Staff directory Inhar Imaz

Inhar Imaz

CSIC Research Scientist
inhar.imaz(ELIMINAR)@icn2.cat
Supramolecular NanoChemistry and Materials

ORCID: 0000-0002-0278-1141

Publications

2024

Metal- and covalent-organic framework mixed matrix membranes for CO2 separation: A perspective on stability and scalability
Shan, Meixia; Geng, Xiumei; Imaz, Inhar; Broto-Ribas, Anna; Ortin-Rubio, Borja; Maspoch, Daniel; Ansaloni, Luca; Peters, Thijs A; Tena, Alberto; Boerrigter, Marcel E; Vermaas, David A Journal Of Membrane Science; 691: 122258. 2024. 10.1016/j.memsci.2023.122258.
Metal- and covalent-organic framework mixed matrix membranes for CO2 separation: A perspective on stability and scalability
Shan, Meixia; Geng, Xiumei; Imaz, Inhar; Broto-Ribas, Anna; Ortin-Rubio, Borja; Maspoch, Daniel; Ansaloni, Luca; Peters, Thijs A; Tena, Alberto; Boerrigter, Marcel E; Vermaas, David A Journal Of Membrane Science; 691: 122258. 2024. 10.1016/j.memsci.2023.122258.
Modulation of the Dynamics of a Two-Dimensional Interweaving Metal-Organic Framework through Induced Hydrogen Bonding
Fernandez-Serinan, Pilar; Roztocki, Kornel; Safarifard, Vahid; Guillerm, Vincent; Rodriguez-Hermida, Sabina; Juanhuix, Judith; Imaz, Inhar; Morsali, Ali; Maspoch, Daniel Inorganic Chemistry; 63 (12): 5552 - 5558. 2024. 10.1021/acs.inorgchem.3c04522.
Modulation of the Dynamics of a Two-Dimensional Interweaving Metal-Organic Framework through Induced Hydrogen Bonding
Fernandez-Serinan, Pilar; Roztocki, Kornel; Safarifard, Vahid; Guillerm, Vincent; Rodriguez-Hermida, Sabina; Juanhuix, Judith; Imaz, Inhar; Morsali, Ali; Maspoch, Daniel Inorganic Chemistry; 63 (12): 5552 - 5558. 2024. 10.1021/acs.inorgchem.3c04522.
Regioswitchable Bingel Bis-Functionalization of Fullerene C70 via Supramolecular Masks
Iannace, Valentina; Sabria, Clara; Xu, Youzhi; von Delius, Max; Imaz, Inhar; Maspoch, Daniel; Feixas, Ferran; Ribas, Xavi Journal Of The American Chemical Society; 146 (8): 5186 - 5194. 2024. 10.1021/jacs.3c10808.
Regioswitchable Bingel Bis-Functionalization of Fullerene C70 via Supramolecular Masks
Iannace, Valentina; Sabria, Clara; Xu, Youzhi; von Delius, Max; Imaz, Inhar; Maspoch, Daniel; Feixas, Ferran; Ribas, Xavi Journal Of The American Chemical Society; 146 (8): 5186 - 5194. 2024. 10.1021/jacs.3c10808.

2023

A mesoporous Zr-based metal-organic framework driven by the assembly of an octatopic linker
Ortin-Rubio, B; Perona-Bermejo, C; del Pino, JA; Carmona, FJ; Gandara, F; Navarro, JAR; Juanhuix, J; Imaz, I; Maspoch, D Chemical Communications; 59 (50): 7803 - 7806. 2023. 10.1039/d3cc01831h. IF: 4.900
A mesoporous Zr-based metal-organic framework driven by the assembly of an octatopic linker
Ortin-Rubio, B; Perona-Bermejo, C; del Pino, JA; Carmona, FJ; Gandara, F; Navarro, JAR; Juanhuix, J; Imaz, I; Maspoch, D Chemical Communications; 59 (50): 7803 - 7806. 2023. 10.1039/d3cc01831h. IF: 4.900
Assembly of Covalent Organic Frameworks into Colloidal Photonic Crystals
Fonseca, J; Meng, LX; Moronta, P; Imaz, I; Lopez, C; Maspoch, D Journal Of The American Chemical Society; 145 (37): 20163 - 20168. 2023. 10.1021/jacs.3c06265. IF: 15.000
Assembly of Covalent Organic Frameworks into Colloidal Photonic Crystals
Fonseca, J; Meng, LX; Moronta, P; Imaz, I; Lopez, C; Maspoch, D Journal Of The American Chemical Society; 145 (37): 20163 - 20168. 2023. 10.1021/jacs.3c06265. IF: 15.000
Hf/porphyrin-based metal-organic framework PCN-224 for CO2 cycloaddition with epoxides
Carrasco, S; Orcajo, G; Martinez, F; Imaz, I; Arenas-Esteban, D; Maspoch, D; Bals, S; Calleja, G; Horcajada, P Materials Today Advances; 19: 100390. 2023. 10.1016/j.mtadv.2023.100390. IF: 10.000
Hf/porphyrin-based metal-organic framework PCN-224 for CO2 cycloaddition with epoxides
Carrasco, S; Orcajo, G; Martinez, F; Imaz, I; Arenas-Esteban, D; Maspoch, D; Bals, S; Calleja, G; Horcajada, P Materials Today Advances; 19: 100390. 2023. 10.1016/j.mtadv.2023.100390. IF: 10.000
Improvement of carbon dioxide electroreduction by crystal surface modification of ZIF-8
Zhang, T; Liu, H; Han, X; Biset-Peiro, M; Yang, YH; Imaz, I; Maspoch, D; Yang, B; Morante, JR; Arbiol, J Dalton Transactions; 52 (16): 5234 - 5242. 2023. 10.1039/d3dt00185g. IF: 4.000
Improvement of carbon dioxide electroreduction by crystal surface modification of ZIF-8
Zhang, T; Liu, H; Han, X; Biset-Peiro, M; Yang, YH; Imaz, I; Maspoch, D; Yang, B; Morante, JR; Arbiol, J Dalton Transactions; 52 (16): 5234 - 5242. 2023. 10.1039/d3dt00185g. IF: 4.000
Interfacial phenomena in nanotechnological applications for water remediation
Esplandiu Egido, María José Reference Module In Chemistry, Molecular Sciences And Chemical Engineering; 2023. 10.1016/B978-0-323-85669-0.00066-0.
Interfacial phenomena in nanotechnological applications for water remediation
Esplandiu Egido, María José Reference Module In Chemistry, Molecular Sciences And Chemical Engineering; 2023. 10.1016/B978-0-323-85669-0.00066-0.
Isoreticular Contraction of Metal-Organic Frameworks Induced by Cleavage of Covalent Bonds
Yang, YH; Fernández-Seriñán, P; Imaz, I; Gándara, F; Handke, M; Ortín-Rubio, B; Juanhuix, J; Maspoch, D Journal Of The American Chemical Society; 145 (31): 17398 - 17405. 2023. 10.1021/jacs.3c05469. IF: 15.000
Isoreticular Contraction of Metal-Organic Frameworks Induced by Cleavage of Covalent Bonds
Yang, YH; Fernández-Seriñán, P; Imaz, I; Gándara, F; Handke, M; Ortín-Rubio, B; Juanhuix, J; Maspoch, D Journal Of The American Chemical Society; 145 (31): 17398 - 17405. 2023. 10.1021/jacs.3c05469. IF: 15.000
Molecular Layer Deposition of Zeolitic Imidazolate Framework-8 Films
Smets, J; Cruz, AJ; Rubio-Gimenez, V; Tietze, ML; Kravchenko, DE; Arnauts, G; Matavz, A; Wauteraerts, N; Tu, M; Marcoen, K; Imaz, I; Maspoch, D; Korytov, M; Vereecken, PM; De Feyter, S; Hauffman, T; Ameloot, R Chemistry Of Materials; 2023. 10.1021/acs.chemmater.2c03439. IF: 8.600
Molecular Layer Deposition of Zeolitic Imidazolate Framework-8 Films
Smets, J; Cruz, AJ; Rubio-Gimenez, V; Tietze, ML; Kravchenko, DE; Arnauts, G; Matavz, A; Wauteraerts, N; Tu, M; Marcoen, K; Imaz, I; Maspoch, D; Korytov, M; Vereecken, PM; De Feyter, S; Hauffman, T; Ameloot, R Chemistry Of Materials; 2023. 10.1021/acs.chemmater.2c03439. IF: 8.600
Monolithic Zirconium-Based Metal-Organic Frameworks for Energy-Efficient Water Adsorption Applications
Camur, C; Babu, R; del Pino, JAS; Rampal, N; Perez-Carvajal, J; Hugenell, P; Ernst, SJ; Silvestre-Albero, J; Imaz, I; Madden, DG; Maspoch, D; Fairen-Jimenez, D Advanced Materials; 35 (23) 2023. 10.1002/adma.202209104. IF: 29.400
Monolithic Zirconium-Based Metal-Organic Frameworks for Energy-Efficient Water Adsorption Applications
Camur, C; Babu, R; del Pino, JAS; Rampal, N; Perez-Carvajal, J; Hugenell, P; Ernst, SJ; Silvestre-Albero, J; Imaz, I; Madden, DG; Maspoch, D; Fairen-Jimenez, D Advanced Materials; 35 (23) 2023. 10.1002/adma.202209104. IF: 29.400
Multifunctional, Hybrid Materials Design via Spray-Drying: Much more than Just Drying
Wintzheimer, S; Luthardt, L; Cao, KLA; Imaz, I; Maspoch, D; Ogi, T; Bück, A; Debecker, DP; Faustini, M; Mandel, K Advanced Materials; 35 (47): e2306648. 2023. 10.1002/adma.202306648. IF: 29.400
Multifunctional, Hybrid Materials Design via Spray-Drying: Much more than Just Drying
Wintzheimer, S; Luthardt, L; Cao, KLA; Imaz, I; Maspoch, D; Ogi, T; Bück, A; Debecker, DP; Faustini, M; Mandel, K Advanced Materials; 35 (47): e2306648. 2023. 10.1002/adma.202306648. IF: 29.400
Net-clipping as a top-down approach for the prediction of topologies of MOFs built from reduced-symmetry linkers
Ortin-Rubio, B; Rostoll-Berenguer, J; Vila, C; Proserpio, DM; Guillerm, V; Juanhuix, J; Imaz, I; Maspoch, D Chemical Science; 14 (45): 12984 - 12994. 2023. 10.1039/d3sc04406h. IF: 8.400
Net-clipping as a top-down approach for the prediction of topologies of MOFs built from reduced-symmetry linkers
Ortin-Rubio, B; Rostoll-Berenguer, J; Vila, C; Proserpio, DM; Guillerm, V; Juanhuix, J; Imaz, I; Maspoch, D Chemical Science; 14 (45): 12984 - 12994. 2023. 10.1039/d3sc04406h. IF: 8.400
Retrosynthetic Analysis Applied to Clip-off Chemistry: Synthesis of Four Rh(II)-Based Complexes as Proof-of-Concept
Broto-Ribas, A; Ruiz-Relaño, S; Albalad, J; Yang, YH; Gándara, F; Juanhuix, J; Imaz, I; Maspoch, D Angewandte Chemie (International Ed. Print); 62 (48): e202310354. 2023. 10.1002/anie.202310354. IF: 16.600
Retrosynthetic Analysis Applied to Clip-off Chemistry: Synthesis of Four Rh(II)-Based Complexes as Proof-of-Concept
Broto-Ribas, A; Ruiz-Relaño, S; Albalad, J; Yang, YH; Gándara, F; Juanhuix, J; Imaz, I; Maspoch, D Angewandte Chemie (International Ed. Print); 62 (48): e202310354. 2023. 10.1002/anie.202310354. IF: 16.600
Self-assembly of colloidal metal-organic framework (MOF) particles
Fonseca, J; Meng, LX; Imaz, I; Maspoch, D Chemical Society Reviews; 52 (7): 2528 - 2543. 2023. 10.1039/d2cs00858k. IF: 46.200
Self-assembly of colloidal metal-organic framework (MOF) particles
Fonseca, J; Meng, LX; Imaz, I; Maspoch, D Chemical Society Reviews; 52 (7): 2528 - 2543. 2023. 10.1039/d2cs00858k. IF: 46.200
Stepwise assembly of heterometallic, heteroleptic "triblock Janus-type" metal-organic polyhedra
von Baeckmann, C; Ruiz-Relano, S; Imaz, I; Handke, M; Juanhuix, J; Gandara, F; Carne-Sanchez, A; Maspoch, D Chemical Communications; 59 (23): 3423 - 3426. 2023. 10.1039/d2cc06815j. IF: 4.900
Stepwise assembly of heterometallic, heteroleptic "triblock Janus-type" metal-organic polyhedra
von Baeckmann, C; Ruiz-Relano, S; Imaz, I; Handke, M; Juanhuix, J; Gandara, F; Carne-Sanchez, A; Maspoch, D Chemical Communications; 59 (23): 3423 - 3426. 2023. 10.1039/d2cc06815j. IF: 4.900

2022

Antibacterial Films Based on MOF Composites that Release Iodine Passively or Upon Triggering by Near-Infrared Light
Han X., Boix G., Balcerzak M., Moriones O.H., Cano-Sarabia M., Cortés P., Bastús N., Puntes V., Llagostera M., Imaz I., Maspoch D. Advanced Functional Materials; 32 (19, 2112902) 2022. 10.1002/adfm.202112902. IF: 18.808

Multidrug-resistant bacteria have become a global health problem for which new prophylactic strategies are now needed, including surface-coatings for hospital spaces and medical equipment. This work reports the preparation and functional validation of a metal-organic framework (MOF) based composite for the triggered controlled release of iodine, an antimicrobial element that does not generate resistance. It comprises beads of the iodophilic MOF UiO-66 containing encapsulated gold nanorods (AuNRs) coated with a silica shell. Irradiation of the AuNRs with near-infrared light (NIR) provokes a photothermal effect and the resultant heat actively liberates the iodine. After validating the performance of this composite, it is integrated into a polymer for the development of antibacterial films. This work assesses the adsorption of iodine into these composite films, as well as its passive long-term release and active light-triggered. Finally, this work validates the antibacterial activity of the composite films in vitro against gram-positive and gram-negative bacteria. The findings will surely inform the development of new prophylactic treatments. © 2022 Wiley-VCH GmbH.

View abstract
Antibacterial Films Based on MOF Composites that Release Iodine Passively or Upon Triggering by Near-Infrared Light
Han X., Boix G., Balcerzak M., Moriones O.H., Cano-Sarabia M., Cortés P., Bastús N., Puntes V., Llagostera M., Imaz I., Maspoch D. Advanced Functional Materials; 32 (19, 2112902) 2022. 10.1002/adfm.202112902. IF: 18.808

Multidrug-resistant bacteria have become a global health problem for which new prophylactic strategies are now needed, including surface-coatings for hospital spaces and medical equipment. This work reports the preparation and functional validation of a metal-organic framework (MOF) based composite for the triggered controlled release of iodine, an antimicrobial element that does not generate resistance. It comprises beads of the iodophilic MOF UiO-66 containing encapsulated gold nanorods (AuNRs) coated with a silica shell. Irradiation of the AuNRs with near-infrared light (NIR) provokes a photothermal effect and the resultant heat actively liberates the iodine. After validating the performance of this composite, it is integrated into a polymer for the development of antibacterial films. This work assesses the adsorption of iodine into these composite films, as well as its passive long-term release and active light-triggered. Finally, this work validates the antibacterial activity of the composite films in vitro against gram-positive and gram-negative bacteria. The findings will surely inform the development of new prophylactic treatments. © 2022 Wiley-VCH GmbH.

View abstract
Clip-off Chemistry: Synthesis by Programmed Disassembly of Reticular Materials**
Yang Y., Broto-Ribas A., Ortín-Rubio B., Imaz I., Gándara F., Carné-Sánchez A., Guillerm V., Jurado S., Busqué F., Juanhuix J., Maspoch D. Angewandte Chemie - International Edition; 61 (4, e202111228) 2022. 10.1002/anie.202111228. IF: 15.336

Bond breaking is an essential process in chemical transformations and the ability of researchers to strategically dictate which bonds in a given system will be broken translates to greater synthetic control. Here, we report extending the concept of selective bond breaking to reticular materials in a new synthetic approach that we call Clip-off Chemistry. We show that bond-breaking in these structures can be controlled at the molecular level; is periodic, quantitative, and selective; is effective in reactions performed in either solid or liquid phases; and can occur in a single-crystal-to-single-crystal fashion involving the entire bulk precursor sample. We validate Clip-off Chemistry by synthesizing two topologically distinct 3D metal-organic frameworks (MOFs) from two reported 3D MOFs, and a metal-organic macrocycle from metal-organic polyhedra (MOP). Clip-off Chemistry opens the door to the programmed disassembly of reticular materials and thus to the design and synthesis of new molecules and materials. © 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH

View abstract
Clip-off Chemistry: Synthesis by Programmed Disassembly of Reticular Materials**
Yang Y., Broto-Ribas A., Ortín-Rubio B., Imaz I., Gándara F., Carné-Sánchez A., Guillerm V., Jurado S., Busqué F., Juanhuix J., Maspoch D. Angewandte Chemie - International Edition; 61 (4, e202111228) 2022. 10.1002/anie.202111228. IF: 15.336

Bond breaking is an essential process in chemical transformations and the ability of researchers to strategically dictate which bonds in a given system will be broken translates to greater synthetic control. Here, we report extending the concept of selective bond breaking to reticular materials in a new synthetic approach that we call Clip-off Chemistry. We show that bond-breaking in these structures can be controlled at the molecular level; is periodic, quantitative, and selective; is effective in reactions performed in either solid or liquid phases; and can occur in a single-crystal-to-single-crystal fashion involving the entire bulk precursor sample. We validate Clip-off Chemistry by synthesizing two topologically distinct 3D metal-organic frameworks (MOFs) from two reported 3D MOFs, and a metal-organic macrocycle from metal-organic polyhedra (MOP). Clip-off Chemistry opens the door to the programmed disassembly of reticular materials and thus to the design and synthesis of new molecules and materials. © 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH

View abstract
Coloration in Supraparticles Assembled from Polyhedral Metal-Organic Framework Particles
Wang J., Liu Y., Bleyer G., Goerlitzer E.S.A., Englisch S., Przybilla T., Mbah C.F., Engel M., Spiecker E., Imaz I., Maspoch D., Vogel N. Angewandte Chemie - International Edition; 61 (16, e202117455) 2022. 10.1002/anie.202117455. IF: 15.336

Supraparticles are spherical colloidal crystals prepared by confined self-assembly processes. A particularly appealing property of these microscale structures is the structural color arising from interference of light with their building blocks. Here, we assemble supraparticles with high structural order that exhibit coloration from uniform, polyhedral metal–organic framework (MOF) particles. We analyse the structural coloration as a function of the size of these anisotropic building blocks and their internal structure. We attribute the angle-dependent coloration of the MOF supraparticles to the presence of ordered, onion-like layers at the outermost regions. Surprisingly, even though different shapes of the MOF particles have different propensities to form these onion layers, all supraparticle dispersions show well-visible macroscopic coloration, indicating that local ordering is sufficient to generate interference effects. © 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

View abstract
Coloration in Supraparticles Assembled from Polyhedral Metal-Organic Framework Particles
Wang J., Liu Y., Bleyer G., Goerlitzer E.S.A., Englisch S., Przybilla T., Mbah C.F., Engel M., Spiecker E., Imaz I., Maspoch D., Vogel N. Angewandte Chemie - International Edition; 61 (16, e202117455) 2022. 10.1002/anie.202117455. IF: 15.336

Supraparticles are spherical colloidal crystals prepared by confined self-assembly processes. A particularly appealing property of these microscale structures is the structural color arising from interference of light with their building blocks. Here, we assemble supraparticles with high structural order that exhibit coloration from uniform, polyhedral metal–organic framework (MOF) particles. We analyse the structural coloration as a function of the size of these anisotropic building blocks and their internal structure. We attribute the angle-dependent coloration of the MOF supraparticles to the presence of ordered, onion-like layers at the outermost regions. Surprisingly, even though different shapes of the MOF particles have different propensities to form these onion layers, all supraparticle dispersions show well-visible macroscopic coloration, indicating that local ordering is sufficient to generate interference effects. © 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

View abstract
Metal-Organic Frameworks: Why Make Them Small?
Wang, JM; Imaz, I; Maspoch, D Small Structures; 3 (1) 2022. 10.1002/sstr.202100126. IF: 11.343
Metal-Organic Frameworks: Why Make Them Small?
Wang, JM; Imaz, I; Maspoch, D Small Structures; 3 (1) 2022. 10.1002/sstr.202100126. IF: 11.343
Synthesis of the two isomers of heteroleptic Rh12L6L′6 metal-organic polyhedra by screening of complementary linkers
Broto-Ribas A., Gutiérrez M.S., Imaz I., Carné-Sánchez A., Gándara F., Juanhuix J., Maspoch D. Chemical Communications; 2022. 10.1039/d2cc03220a.

We have synthesised and characterised the two possible isomers of heteroleptic trigonal antiprismatic M12L6L′6 MOPs by screening reactions of rhodium acetate with different pairs of complementary dicarboxylate linkers. The resulting 12 new MOPs (eight of isomer A + four of isomer B) are microporous in the solid state, exhibiting Brunauer-Emmett-Teller (BET) surface areas as high as 770 m2 g−1 © 2022 The Royal Society of Chemistry.

View abstract
Synthesis of the two isomers of heteroleptic Rh12L6L′6 metal-organic polyhedra by screening of complementary linkers
Broto-Ribas A., Gutiérrez M.S., Imaz I., Carné-Sánchez A., Gándara F., Juanhuix J., Maspoch D. Chemical Communications; 2022. 10.1039/d2cc03220a.

We have synthesised and characterised the two possible isomers of heteroleptic trigonal antiprismatic M12L6L′6 MOPs by screening reactions of rhodium acetate with different pairs of complementary dicarboxylate linkers. The resulting 12 new MOPs (eight of isomer A + four of isomer B) are microporous in the solid state, exhibiting Brunauer-Emmett-Teller (BET) surface areas as high as 770 m2 g−1 © 2022 The Royal Society of Chemistry.

View abstract

2021

A three-shell supramolecular complex enables the symmetry-mismatched chemo- and regioselective bis-functionalization of C60
Ubasart E., Borodin O., Fuertes-Espinosa C., Xu Y., García-Simón C., Gómez L., Juanhuix J., Gándara F., Imaz I., Maspoch D., von Delius M., Ribas X. Nature Chemistry; 13 (5): 420 - 427. 2021. 10.1038/s41557-021-00658-6. IF: 24.427

Molecular Russian dolls (matryoshkas) have proven useful for testing the limits of preparative supramolecular chemistry but applications of these architectures to problems in other fields are elusive. Here we report a three-shell, matryoshka-like complex—in which C60 sits inside a cycloparaphenylene nanohoop, which in turn is encapsulated inside a self-assembled nanocapsule—that can be used to address a long-standing challenge in fullerene chemistry, namely the selective formation of a particular fullerene bis-adduct. Spectroscopic evidence indicates that the ternary complex is sufficiently stable in solution for the two outer shells to affect the addition chemistry of the fullerene guest. When the complex is subjected to Bingel cyclopropanation conditions, the exclusive formation of a single trans-3 fullerene bis-adduct was observed in a reaction that typically yields more than a dozen products. The selectivity facilitated by this matryoshka-like approach appears to be a general phenomenon and could be useful for applications where regioisomerically pure C60 bis-adducts have been shown to have superior properties compared with isomer mixtures. [Figure not available: see fulltext.] © 2021, The Author(s), under exclusive licence to Springer Nature Limited.

View abstract
A three-shell supramolecular complex enables the symmetry-mismatched chemo- and regioselective bis-functionalization of C60
Ubasart E., Borodin O., Fuertes-Espinosa C., Xu Y., García-Simón C., Gómez L., Juanhuix J., Gándara F., Imaz I., Maspoch D., von Delius M., Ribas X. Nature Chemistry; 13 (5): 420 - 427. 2021. 10.1038/s41557-021-00658-6. IF: 24.427

Molecular Russian dolls (matryoshkas) have proven useful for testing the limits of preparative supramolecular chemistry but applications of these architectures to problems in other fields are elusive. Here we report a three-shell, matryoshka-like complex—in which C60 sits inside a cycloparaphenylene nanohoop, which in turn is encapsulated inside a self-assembled nanocapsule—that can be used to address a long-standing challenge in fullerene chemistry, namely the selective formation of a particular fullerene bis-adduct. Spectroscopic evidence indicates that the ternary complex is sufficiently stable in solution for the two outer shells to affect the addition chemistry of the fullerene guest. When the complex is subjected to Bingel cyclopropanation conditions, the exclusive formation of a single trans-3 fullerene bis-adduct was observed in a reaction that typically yields more than a dozen products. The selectivity facilitated by this matryoshka-like approach appears to be a general phenomenon and could be useful for applications where regioisomerically pure C60 bis-adducts have been shown to have superior properties compared with isomer mixtures. [Figure not available: see fulltext.] © 2021, The Author(s), under exclusive licence to Springer Nature Limited.

View abstract
Assembly of Colloidal Clusters Driven by the Polyhedral Shape of Metal-Organic Framework Particles
Liu Y., Wang J., Imaz I., Maspoch D. Journal of the American Chemical Society; 143 (33): 12943 - 12947. 2021. 10.1021/jacs.1c05363. IF: 15.419

Control of the assembly of colloidal particles into discrete or higher-dimensional architectures is important for the design of myriad materials, including plasmonic sensing systems and photonic crystals. Here, we report a new approach that uses the polyhedral shape of metal-organic-framework (MOF) particles to direct the assembly of colloidal clusters. This approach is based on controlling the attachment of a single spherical polystyrene particle on each face of a polyhedral particle via colloidal fusion synthesis, so that the polyhedral shape defines the final coordination number, which is equal to the number of faces, and geometry of the assembled colloidal cluster. As a proof of concept, we assembled six-coordinated (6-c) octahedral and 8-c cubic clusters using cubic ZIF-8 and octahedral UiO-66 core particles. Moreover, we extended this approach to synthesize a highly coordinated 12-c cuboctahedral cluster from a rhombic dodecahedral ZIF-8 particle. We anticipate that the synthesized colloidal clusters could be further evolved into spherical core-shell MOF@polystyrene particles under conditions that promote a higher fusion degree, thus expanding the methods available for the synthesis of MOF-polymer composites. ©

View abstract
Assembly of Colloidal Clusters Driven by the Polyhedral Shape of Metal-Organic Framework Particles
Liu Y., Wang J., Imaz I., Maspoch D. Journal of the American Chemical Society; 143 (33): 12943 - 12947. 2021. 10.1021/jacs.1c05363. IF: 15.419

Control of the assembly of colloidal particles into discrete or higher-dimensional architectures is important for the design of myriad materials, including plasmonic sensing systems and photonic crystals. Here, we report a new approach that uses the polyhedral shape of metal-organic-framework (MOF) particles to direct the assembly of colloidal clusters. This approach is based on controlling the attachment of a single spherical polystyrene particle on each face of a polyhedral particle via colloidal fusion synthesis, so that the polyhedral shape defines the final coordination number, which is equal to the number of faces, and geometry of the assembled colloidal cluster. As a proof of concept, we assembled six-coordinated (6-c) octahedral and 8-c cubic clusters using cubic ZIF-8 and octahedral UiO-66 core particles. Moreover, we extended this approach to synthesize a highly coordinated 12-c cuboctahedral cluster from a rhombic dodecahedral ZIF-8 particle. We anticipate that the synthesized colloidal clusters could be further evolved into spherical core-shell MOF@polystyrene particles under conditions that promote a higher fusion degree, thus expanding the methods available for the synthesis of MOF-polymer composites. ©

View abstract
Engineering covalent organic frameworks in the modulation of photocatalytic degradation of pollutants under visible light conditions
Jiménez-Almarza A., López-Magano A., Cano R., Ortín-Rubio B., Díaz-García D., Gomez-Ruiz S., Imaz I., Maspoch D., Mas-Ballesté R., Alemán J. Materials Today Chemistry; 22 (100548) 2021. 10.1016/j.mtchem.2021.100548. IF: 8.301

Mixtures of triphenylamine (TPA) and phenyl phenothiazine (PTH) fragments have been incorporated into a series of extended polyimine structures that have been applied in the photodegradation of pollutants of different nature under visible light irradiation. Results obtained revealed that materials containing PTH as the sole photoactive unit resulted in the most active photocatalytic material in the degradation of polybrominated diphenyl ether-1 and Sudan Red III. In contrast, the covalent organic framework containing only TPA acted as the best photocatalyst for the degradation of Methylene Blue. These different trends are related to the versatility of PTH moiety to trigger both photoredox and energy transfer processes, while TPA is only an effective energy transfer catalyst. © 2021 Elsevier Ltd

View abstract
Engineering covalent organic frameworks in the modulation of photocatalytic degradation of pollutants under visible light conditions
Jiménez-Almarza A., López-Magano A., Cano R., Ortín-Rubio B., Díaz-García D., Gomez-Ruiz S., Imaz I., Maspoch D., Mas-Ballesté R., Alemán J. Materials Today Chemistry; 22 (100548) 2021. 10.1016/j.mtchem.2021.100548. IF: 8.301

Mixtures of triphenylamine (TPA) and phenyl phenothiazine (PTH) fragments have been incorporated into a series of extended polyimine structures that have been applied in the photodegradation of pollutants of different nature under visible light irradiation. Results obtained revealed that materials containing PTH as the sole photoactive unit resulted in the most active photocatalytic material in the degradation of polybrominated diphenyl ether-1 and Sudan Red III. In contrast, the covalent organic framework containing only TPA acted as the best photocatalyst for the degradation of Methylene Blue. These different trends are related to the versatility of PTH moiety to trigger both photoredox and energy transfer processes, while TPA is only an effective energy transfer catalyst. © 2021 Elsevier Ltd

View abstract
Heterogeneous catalysts with programmable topologies generated by reticulation of organocatalysts into metal-organic frameworks: The case of squaramide
Broto-Ribas A., Vignatti C., Jimenez-Almarza A., Luis-Barrera J., Dolatkhah Z., Gándara F., Imaz I., Mas-Ballesté R., Alemán J., Maspoch D. Nano Research; 14 (2): 458 - 465. 2021. 10.1007/s12274-020-2779-8. IF: 8.897

A well-established strategy to synthesize heterogeneous, metal-organic framework (MOF) catalysts that exhibit nanoconfinement effects, and specific pores with highly-localized catalytic sites, is to use organic linkers containing organocatalytic centers. Here, we report that by combining this linker approach with reticular chemistry, and exploiting three-dimensioanl (3D) MOF-structural data from the Cambridge Structural Database, we have designed four heterogeneous MOF-based catalysts for standard organic transformations. These programmable MOFs are isoreticular versions of pcu IRMOF-16, fcu UiO-68 and pillared-pcu SNU-8X, the three most common topologies of MOFs built from the organic linker p,p’-terphenyldicarboxylic acid (tpdc). To synthesize the four squaramide-based MOFs, we designed and synthesized a linker, 4,4’-((3,4‐dioxocyclobut‐1‐ene‐1,2‐diyl)bis(azanedyil))dibenzoic acid (Sq_tpdc), which is identical in directionality and length to tpdc but which contains organocatalytic squaramide centers. Squaramides were chosen because their immobilization into a framework enhances its reactivity and stability while avoiding any self-quenching phenomena. Therefore, the four MOFs share the same organocatalytic squaramide moiety, but confine it within distinct pore environments. We then evaluated these MOFs as heterogeneous H-bonding catalysts in organic transformations: a Friedel-Crafts alkylation and an epoxide ring-opening. Some of them exhibited good performance in both reactions but all showed distinct catalytic profiles that reflect their structural differences. [Figure not available: see fulltext.]. © 2020, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.

View abstract
Heterogeneous catalysts with programmable topologies generated by reticulation of organocatalysts into metal-organic frameworks: The case of squaramide
Broto-Ribas A., Vignatti C., Jimenez-Almarza A., Luis-Barrera J., Dolatkhah Z., Gándara F., Imaz I., Mas-Ballesté R., Alemán J., Maspoch D. Nano Research; 14 (2): 458 - 465. 2021. 10.1007/s12274-020-2779-8. IF: 8.897

A well-established strategy to synthesize heterogeneous, metal-organic framework (MOF) catalysts that exhibit nanoconfinement effects, and specific pores with highly-localized catalytic sites, is to use organic linkers containing organocatalytic centers. Here, we report that by combining this linker approach with reticular chemistry, and exploiting three-dimensioanl (3D) MOF-structural data from the Cambridge Structural Database, we have designed four heterogeneous MOF-based catalysts for standard organic transformations. These programmable MOFs are isoreticular versions of pcu IRMOF-16, fcu UiO-68 and pillared-pcu SNU-8X, the three most common topologies of MOFs built from the organic linker p,p’-terphenyldicarboxylic acid (tpdc). To synthesize the four squaramide-based MOFs, we designed and synthesized a linker, 4,4’-((3,4‐dioxocyclobut‐1‐ene‐1,2‐diyl)bis(azanedyil))dibenzoic acid (Sq_tpdc), which is identical in directionality and length to tpdc but which contains organocatalytic squaramide centers. Squaramides were chosen because their immobilization into a framework enhances its reactivity and stability while avoiding any self-quenching phenomena. Therefore, the four MOFs share the same organocatalytic squaramide moiety, but confine it within distinct pore environments. We then evaluated these MOFs as heterogeneous H-bonding catalysts in organic transformations: a Friedel-Crafts alkylation and an epoxide ring-opening. Some of them exhibited good performance in both reactions but all showed distinct catalytic profiles that reflect their structural differences. [Figure not available: see fulltext.]. © 2020, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.

View abstract
Heterogeneous Microscopic Dynamics of Intruded Water in a Superhydrophobic Nanoconfinement: Neutron Scattering and Molecular Modeling
Wolanin J., Michel L., Tabacchioni D., Zanotti J.M., Peters J., Imaz I., Coasne B., Plazanet M., Picard C. Journal of Physical Chemistry B; 125 (36): 10392 - 10399. 2021. 10.1021/acs.jpcb.1c06791. IF: 2.991

With their strong confining porosity and versatile surface chemistry, zeolitic imidazolate frameworks—including the prototypical ZIF-8—display exceptional properties for various applications. In particular, the forced intrusion of water at high pressure (∼25 MPa) into ZIF-8 nanopores is of interest for energy storage. Such a system reveals also ideal to study experimentally water dynamics and thermodynamics in an ultrahydrophobic confinement. Here, we report on neutron scattering experiments to probe the molecular dynamics of water within ZIF-8 nanopores under high pressure up to 38 MPa. In addition to an overall confinement-induced slowing down, we provide evidence for strong dynamical heterogeneities with different underlying molecular dynamics. Using complementary molecular simulations, these heterogeneities are found to correspond to different microscopic mechanisms inherent to vicinal molecules located in strongly adsorbing sites (ligands) and other molecules nanoconfined in the cavity center. These findings unveil a complex microscopic dynamics, which results from the combination of surface residence times and exchanges between the cavity surface and center. © 2021 American Chemical Society

View abstract
Heterogeneous Microscopic Dynamics of Intruded Water in a Superhydrophobic Nanoconfinement: Neutron Scattering and Molecular Modeling
Wolanin J., Michel L., Tabacchioni D., Zanotti J.M., Peters J., Imaz I., Coasne B., Plazanet M., Picard C. Journal of Physical Chemistry B; 125 (36): 10392 - 10399. 2021. 10.1021/acs.jpcb.1c06791. IF: 2.991

With their strong confining porosity and versatile surface chemistry, zeolitic imidazolate frameworks—including the prototypical ZIF-8—display exceptional properties for various applications. In particular, the forced intrusion of water at high pressure (∼25 MPa) into ZIF-8 nanopores is of interest for energy storage. Such a system reveals also ideal to study experimentally water dynamics and thermodynamics in an ultrahydrophobic confinement. Here, we report on neutron scattering experiments to probe the molecular dynamics of water within ZIF-8 nanopores under high pressure up to 38 MPa. In addition to an overall confinement-induced slowing down, we provide evidence for strong dynamical heterogeneities with different underlying molecular dynamics. Using complementary molecular simulations, these heterogeneities are found to correspond to different microscopic mechanisms inherent to vicinal molecules located in strongly adsorbing sites (ligands) and other molecules nanoconfined in the cavity center. These findings unveil a complex microscopic dynamics, which results from the combination of surface residence times and exchanges between the cavity surface and center. © 2021 American Chemical Society

View abstract
Macroscopic Ultralight Aerogel Monoliths of Imine-based Covalent Organic Frameworks
Martín-Illán J.Á., Rodríguez-San-Miguel D., Castillo O., Beobide G., Perez-Carvajal J., Imaz I., Maspoch D., Zamora F. Angewandte Chemie - International Edition; 60 (25): 13969 - 13977. 2021. 10.1002/anie.202100881. IF: 15.336

The use of covalent organic frameworks (COFs) in practical applications demands shaping them into macroscopic objects, which remains challenging. Herein, we report a simple three-step method to produce COF aerogels, based on sol-gel transition, solvent-exchange, and supercritical CO2 drying, in which 2D imine-based COF sheets link together to form hierarchical porous structures. The resultant COF aerogel monoliths have extremely low densities (ca. 0.02 g cm−3), high porosity (total porosity values of ca. 99 %), and mechanically behave as elastic materials under a moderate strain (<25–35 %) but become plastic under greater strain. Moreover, these COF aerogels maintain the micro- and meso-porosity of their constituent COFs, and show excellent absorption capacity (e.g. toluene uptake: 32 g g−1), with high removal efficiency (ca. 99 %). The same three-step method can be used to create functional composites of these COF aerogels with nanomaterials. © 2021 Wiley-VCH GmbH

View abstract
Macroscopic Ultralight Aerogel Monoliths of Imine-based Covalent Organic Frameworks
Martín-Illán J.Á., Rodríguez-San-Miguel D., Castillo O., Beobide G., Perez-Carvajal J., Imaz I., Maspoch D., Zamora F. Angewandte Chemie - International Edition; 60 (25): 13969 - 13977. 2021. 10.1002/anie.202100881. IF: 15.336

The use of covalent organic frameworks (COFs) in practical applications demands shaping them into macroscopic objects, which remains challenging. Herein, we report a simple three-step method to produce COF aerogels, based on sol-gel transition, solvent-exchange, and supercritical CO2 drying, in which 2D imine-based COF sheets link together to form hierarchical porous structures. The resultant COF aerogel monoliths have extremely low densities (ca. 0.02 g cm−3), high porosity (total porosity values of ca. 99 %), and mechanically behave as elastic materials under a moderate strain (<25–35 %) but become plastic under greater strain. Moreover, these COF aerogels maintain the micro- and meso-porosity of their constituent COFs, and show excellent absorption capacity (e.g. toluene uptake: 32 g g−1), with high removal efficiency (ca. 99 %). The same three-step method can be used to create functional composites of these COF aerogels with nanomaterials. © 2021 Wiley-VCH GmbH

View abstract
Millimeter-Shaped Metal-Organic Framework/Inorganic Nanoparticle Composite as a New Adsorbent for Home Water-Purification Filters
Boix G., Han X., Imaz I., Maspoch D. ACS Applied Materials and Interfaces; 13 (15): 17835 - 17843. 2021. 10.1021/acsami.1c02940. IF: 9.229

Heavy-metal contamination of water is a global problem with an especially severe impact in countries with old or poorly maintained infrastructure for potable water. An increasingly popular solution for ensuring clean and safe drinking water in homes is the use of adsorption-based water filters, given their affordability, efficacy, and simplicity. Herein, we report the preparation and functional validation of a new adsorbent for home water filters, based on our metal-organic framework (MOF) composite containing UiO-66 and cerium(IV) oxide (CeO2) nanoparticles. We began by preparing CeO2@UiO-66 microbeads and then encapsulating them in porous polyethersulfone (PES) granules to obtain millimeter-scale CeO2@UiO-66@PES granules. Next, we validated these granules as an adsorbent for the removal of metals from water by substituting them for the standard adsorbent (ion-exchange resin spheres) inside a commercially available water pitcher from Brita. We assessed their performance according to the American National Standards Institute (ANSI) guideline 53-2019, "Drinking Water Treatment Units - Health Effects Standard". Remarkably, a pitcher loaded with a combination of our CeO2@UiO-66@PES granules and activated carbon at standard ratios met the target reduction thresholds set by NSF/ANSI 53-2019 for all the metals tested: As(III), As(V), Cd(II), Cr(III), Cr(VI), Cu(II), Hg(II), and Pb(II). Throughout the test, the modified pitcher proved to be robust and stable. We are confident that our findings will bring MOF-based adsorbents one step closer to real-world use. © 2021 American Chemical Society.

View abstract
Millimeter-Shaped Metal-Organic Framework/Inorganic Nanoparticle Composite as a New Adsorbent for Home Water-Purification Filters
Boix G., Han X., Imaz I., Maspoch D. ACS Applied Materials and Interfaces; 13 (15): 17835 - 17843. 2021. 10.1021/acsami.1c02940. IF: 9.229

Heavy-metal contamination of water is a global problem with an especially severe impact in countries with old or poorly maintained infrastructure for potable water. An increasingly popular solution for ensuring clean and safe drinking water in homes is the use of adsorption-based water filters, given their affordability, efficacy, and simplicity. Herein, we report the preparation and functional validation of a new adsorbent for home water filters, based on our metal-organic framework (MOF) composite containing UiO-66 and cerium(IV) oxide (CeO2) nanoparticles. We began by preparing CeO2@UiO-66 microbeads and then encapsulating them in porous polyethersulfone (PES) granules to obtain millimeter-scale CeO2@UiO-66@PES granules. Next, we validated these granules as an adsorbent for the removal of metals from water by substituting them for the standard adsorbent (ion-exchange resin spheres) inside a commercially available water pitcher from Brita. We assessed their performance according to the American National Standards Institute (ANSI) guideline 53-2019, "Drinking Water Treatment Units - Health Effects Standard". Remarkably, a pitcher loaded with a combination of our CeO2@UiO-66@PES granules and activated carbon at standard ratios met the target reduction thresholds set by NSF/ANSI 53-2019 for all the metals tested: As(III), As(V), Cd(II), Cr(III), Cr(VI), Cu(II), Hg(II), and Pb(II). Throughout the test, the modified pitcher proved to be robust and stable. We are confident that our findings will bring MOF-based adsorbents one step closer to real-world use. © 2021 American Chemical Society.

View abstract
Photoredox Heterobimetallic Dual Catalysis Using Engineered Covalent Organic Frameworks
López-Magano A., Ortín-Rubio B., Imaz I., Maspoch D., Alemán J., Mas-Ballesté R. ACS Catalysis; 11 (19): 12344 - 12354. 2021. 10.1021/acscatal.1c03634. IF: 13.084

The functionalization of an imine-based layered covalent organic framework (COF), containing phenanthroline units as ligands, has allowed the obtention of a heterobimetallated material. Photoactive Ir and Ni fragments were immobilized within the porous structure of the COF, enabling heterogeneous light-mediated Csp3-Csp2cross-couplings. As radical precursors, potassium benzyl- and alkoxy-trifluoroborates, organic silicates, and proline derivatives were employed, which brings out the good versatility ofIr,Ni@Phen-COF. Moreover, in all the studied cases, an enhanced activity and stability have been observed in comparison with analogous homogenous systems. © 2021 American Chemical Society

View abstract
Photoredox Heterobimetallic Dual Catalysis Using Engineered Covalent Organic Frameworks
López-Magano A., Ortín-Rubio B., Imaz I., Maspoch D., Alemán J., Mas-Ballesté R. ACS Catalysis; 11 (19): 12344 - 12354. 2021. 10.1021/acscatal.1c03634. IF: 13.084

The functionalization of an imine-based layered covalent organic framework (COF), containing phenanthroline units as ligands, has allowed the obtention of a heterobimetallated material. Photoactive Ir and Ni fragments were immobilized within the porous structure of the COF, enabling heterogeneous light-mediated Csp3-Csp2cross-couplings. As radical precursors, potassium benzyl- and alkoxy-trifluoroborates, organic silicates, and proline derivatives were employed, which brings out the good versatility ofIr,Ni@Phen-COF. Moreover, in all the studied cases, an enhanced activity and stability have been observed in comparison with analogous homogenous systems. © 2021 American Chemical Society

View abstract
Synthesis of Polycarboxylate Rhodium(II) Metal–Organic Polyhedra (MOPs) and their use as Building Blocks for Highly Connected Metal–Organic Frameworks (MOFs)
Grancha T., Carné-Sánchez A., Zarekarizi F., Hernández-López L., Albalad J., Khobotov A., Guillerm V., Morsali A., Juanhuix J., Gándara F., Imaz I., Maspoch D. Angewandte Chemie - International Edition; 60 (11): 5729 - 5733. 2021. 10.1002/anie.202013839. IF: 15.336

Use of preformed metal-organic polyhedra (MOPs) as supermolecular building blocks (SBBs) for the synthesis of metal-organic frameworks (MOFs) remains underexplored due to lack of robust functionalized MOPs. Herein we report the use of polycarboxylate cuboctahedral RhII-MOPs for constructing highly-connected MOFs. Cuboctahedral MOPs were functionalized with carboxylic acid groups on their 12 vertices or 24 edges through coordinative or covalent post-synthetic routes, respectively. We then used each isolated polycarboxylate RhII-MOP as 12-c cuboctahedral or 24-c rhombicuboctahedral SBBs that, upon linkage with metallic secondary building units (SBUs), afford bimetallic highly-connected MOFs. The assembly of a pre-synthesized 12-c SBB with a 4-c paddle-wheel SBU, and a 24-c SBB with a 3-c triangular CuII SBU gave rise to bimetallic MOFs having ftw (4,12)-c or rht (3,24)-c topologies, respectively. © 2020 Wiley-VCH GmbH

View abstract
Synthesis of Polycarboxylate Rhodium(II) Metal–Organic Polyhedra (MOPs) and their use as Building Blocks for Highly Connected Metal–Organic Frameworks (MOFs)
Grancha T., Carné-Sánchez A., Zarekarizi F., Hernández-López L., Albalad J., Khobotov A., Guillerm V., Morsali A., Juanhuix J., Gándara F., Imaz I., Maspoch D. Angewandte Chemie - International Edition; 60 (11): 5729 - 5733. 2021. 10.1002/anie.202013839. IF: 15.336

Use of preformed metal-organic polyhedra (MOPs) as supermolecular building blocks (SBBs) for the synthesis of metal-organic frameworks (MOFs) remains underexplored due to lack of robust functionalized MOPs. Herein we report the use of polycarboxylate cuboctahedral RhII-MOPs for constructing highly-connected MOFs. Cuboctahedral MOPs were functionalized with carboxylic acid groups on their 12 vertices or 24 edges through coordinative or covalent post-synthetic routes, respectively. We then used each isolated polycarboxylate RhII-MOP as 12-c cuboctahedral or 24-c rhombicuboctahedral SBBs that, upon linkage with metallic secondary building units (SBUs), afford bimetallic highly-connected MOFs. The assembly of a pre-synthesized 12-c SBB with a 4-c paddle-wheel SBU, and a 24-c SBB with a 3-c triangular CuII SBU gave rise to bimetallic MOFs having ftw (4,12)-c or rht (3,24)-c topologies, respectively. © 2020 Wiley-VCH GmbH

View abstract

2020

Biomimetic Synthesis of Sub-20 nm Covalent Organic Frameworks in Water
Franco C., Rodríguez-San-Miguel D., Sorrenti A., Sevim S., Pons R., Platero-Prats A.E., Pavlovic M., Szilágyi I., Ruiz Gonzalez M.L., González-Calbet J.M., Bochicchio D., Pesce L., Pavan G.M., Imaz I., Cano-Sarabia M., Maspoch D., Pané S., De Mello A.J., Zamora F., Puigmartí-Luis J. Journal of the American Chemical Society; 142 (7): 3540 - 3547. 2020. 10.1021/jacs.9b12389. IF: 14.612

Covalent organic frameworks (COFs) are commonly synthesized under harsh conditions yielding unprocessable powders. Control in their crystallization process and growth has been limited to studies conducted in hazardous organic solvents. Herein, we report a one-pot synthetic method that yields stable aqueous colloidal solutions of sub-20 nm crystalline imine-based COF particles at room temperature and ambient pressure. Additionally, through the combination of experimental and computational studies, we investigated the mechanisms and forces underlying the formation of such imine-based COF colloids in water. Further, we show that our method can be used to process the colloidal solution into 2D and 3D COF shapes as well as to generate a COF ink that can be directly printed onto surfaces. These findings should open new vistas in COF chemistry, enabling new application areas. Copyright © 2020 American Chemical Society.

View abstract
Biomimetic Synthesis of Sub-20 nm Covalent Organic Frameworks in Water
Franco C., Rodríguez-San-Miguel D., Sorrenti A., Sevim S., Pons R., Platero-Prats A.E., Pavlovic M., Szilágyi I., Ruiz Gonzalez M.L., González-Calbet J.M., Bochicchio D., Pesce L., Pavan G.M., Imaz I., Cano-Sarabia M., Maspoch D., Pané S., De Mello A.J., Zamora F., Puigmartí-Luis J. Journal of the American Chemical Society; 142 (7): 3540 - 3547. 2020. 10.1021/jacs.9b12389. IF: 14.612

Covalent organic frameworks (COFs) are commonly synthesized under harsh conditions yielding unprocessable powders. Control in their crystallization process and growth has been limited to studies conducted in hazardous organic solvents. Herein, we report a one-pot synthetic method that yields stable aqueous colloidal solutions of sub-20 nm crystalline imine-based COF particles at room temperature and ambient pressure. Additionally, through the combination of experimental and computational studies, we investigated the mechanisms and forces underlying the formation of such imine-based COF colloids in water. Further, we show that our method can be used to process the colloidal solution into 2D and 3D COF shapes as well as to generate a COF ink that can be directly printed onto surfaces. These findings should open new vistas in COF chemistry, enabling new application areas. Copyright © 2020 American Chemical Society.

View abstract
Dynamic porous coordination polymers built-up from flexible 4,4′-dithiodibenzoate and rigid N-based ligands
Jarrah N., Troyano J., Carné-Sánchez A., Imaz I., Tangestaninejad S., Moghadam M., Maspoch D. Dalton Transactions; 49 (37): 13142 - 13151. 2020. 10.1039/d0dt02411b. IF: 4.174

Herein we report the design, synthesis, structural characterisation and functional testing of a series of Cu(ii) coordination polymers containing flexible 4,4′-dithiodibenzoate ligand (4,4′-DTBA), with or without auxiliary N-donor ligands. Reaction of Cu(ii) with 4,4′-DTBA yielded a 1D coordination polymer (1) based on Cu(ii) paddlewheel units connected by 4,4′-DTBA, to form cyclic loop chains with intramolecular voids that exhibit reversible structural transformations upon subsequent solvent exchange in methanol to afford a new, crystalline, permanently-porous structure (1′). However, when the same reaction was run with pyridine, it formed a porous 2D coordination polymer (2). We have attributed the difference in dimensionality seen in the two products to the coordination of pyridine on the axial site of the Cu(ii) paddle-wheel, which forces flexible 4,4′-DTBA to adopt a different conformation. Reactions in the presence of 4,4′-bipyridine (4,4′-bpy) afforded two new, flexible, 2D coordination polymers (3 4). Lower concentrations of 4,4′-bpy afforded a structure (3) built from 1D chains analogous to those in 1 and connected through 4,4′-bpy linkers coordinated to the axial positions. Interestingly, 3 showed reversible structural transformations triggered by either solvent exchange or thermal treatment, each of which yielded a new crystalline and permanently porous phase (3′). Finally, use of higher concentrations of 4,4′-bpy led to a coordination polymer (4) based on a distorted CuO3N2 trigonal bipyramid, rather than on the Cu(ii) paddlewheel. The connection of these motifs by 4,4′-DTBA resulted in a zig-zag 1D chain connected through 4,4′-bpy ligands to form a porous 2D network. Interestingly, 4 also underwent reversible thermal transformation to yield a microporous coordination polymer (4′). © The Royal Society of Chemistry.

View abstract
Dynamic porous coordination polymers built-up from flexible 4,4′-dithiodibenzoate and rigid N-based ligands
Jarrah N., Troyano J., Carné-Sánchez A., Imaz I., Tangestaninejad S., Moghadam M., Maspoch D. Dalton Transactions; 49 (37): 13142 - 13151. 2020. 10.1039/d0dt02411b. IF: 4.174

Herein we report the design, synthesis, structural characterisation and functional testing of a series of Cu(ii) coordination polymers containing flexible 4,4′-dithiodibenzoate ligand (4,4′-DTBA), with or without auxiliary N-donor ligands. Reaction of Cu(ii) with 4,4′-DTBA yielded a 1D coordination polymer (1) based on Cu(ii) paddlewheel units connected by 4,4′-DTBA, to form cyclic loop chains with intramolecular voids that exhibit reversible structural transformations upon subsequent solvent exchange in methanol to afford a new, crystalline, permanently-porous structure (1′). However, when the same reaction was run with pyridine, it formed a porous 2D coordination polymer (2). We have attributed the difference in dimensionality seen in the two products to the coordination of pyridine on the axial site of the Cu(ii) paddle-wheel, which forces flexible 4,4′-DTBA to adopt a different conformation. Reactions in the presence of 4,4′-bipyridine (4,4′-bpy) afforded two new, flexible, 2D coordination polymers (3 4). Lower concentrations of 4,4′-bpy afforded a structure (3) built from 1D chains analogous to those in 1 and connected through 4,4′-bpy linkers coordinated to the axial positions. Interestingly, 3 showed reversible structural transformations triggered by either solvent exchange or thermal treatment, each of which yielded a new crystalline and permanently porous phase (3′). Finally, use of higher concentrations of 4,4′-bpy led to a coordination polymer (4) based on a distorted CuO3N2 trigonal bipyramid, rather than on the Cu(ii) paddlewheel. The connection of these motifs by 4,4′-DTBA resulted in a zig-zag 1D chain connected through 4,4′-bpy ligands to form a porous 2D network. Interestingly, 4 also underwent reversible thermal transformation to yield a microporous coordination polymer (4′). © The Royal Society of Chemistry.

View abstract
Enzyme-Powered Porous Micromotors Built from a Hierarchical Micro- And Mesoporous UiO-Type Metal-Organic Framework
Yang Y., Arqué X., Patiño T., Guillerm V., Blersch P.-R., Pérez-Carvajal J., Imaz I., Maspoch D., Sánchez S. Journal of the American Chemical Society; 142 (50): 20962 - 20967. 2020. 10.1021/jacs.0c11061. IF: 14.612

Here, we report the design, synthesis, and functional testing of enzyme-powered porous micromotors built from a metal-organic framework (MOF). We began by subjecting a presynthesized microporous UiO-type MOF to ozonolysis, to confer it with mesopores sufficiently large to adsorb and host the enzyme catalase (size: 6-10 nm). We then encapsulated catalase inside the mesopores, observing that they are hosted in those mesopores located at the subsurface of the MOF crystals. In the presence of H2O2 fuel, MOF motors (or MOFtors) exhibit jet-like propulsion enabled by enzymatic generation of oxygen bubbles. Moreover, thanks to their hierarchical pore system, the MOFtors retain sufficient free space for adsorption of additional targeted species, which we validated by testing a MOFtor for removal of rhodamine B during self-propulsion. © 2020 American Chemical Society.

View abstract
Enzyme-Powered Porous Micromotors Built from a Hierarchical Micro- And Mesoporous UiO-Type Metal-Organic Framework
Yang Y., Arqué X., Patiño T., Guillerm V., Blersch P.-R., Pérez-Carvajal J., Imaz I., Maspoch D., Sánchez S. Journal of the American Chemical Society; 142 (50): 20962 - 20967. 2020. 10.1021/jacs.0c11061. IF: 14.612

Here, we report the design, synthesis, and functional testing of enzyme-powered porous micromotors built from a metal-organic framework (MOF). We began by subjecting a presynthesized microporous UiO-type MOF to ozonolysis, to confer it with mesopores sufficiently large to adsorb and host the enzyme catalase (size: 6-10 nm). We then encapsulated catalase inside the mesopores, observing that they are hosted in those mesopores located at the subsurface of the MOF crystals. In the presence of H2O2 fuel, MOF motors (or MOFtors) exhibit jet-like propulsion enabled by enzymatic generation of oxygen bubbles. Moreover, thanks to their hierarchical pore system, the MOFtors retain sufficient free space for adsorption of additional targeted species, which we validated by testing a MOFtor for removal of rhodamine B during self-propulsion. © 2020 American Chemical Society.

View abstract
Green synthesis of imine-based covalent organic frameworks in water
Martín-Illán J.Á., Rodríguez-San-Miguel D., Rodríguez-San-Miguel D., Franco C., Imaz I., Maspoch D., Maspoch D., Puigmartí-Luis J., Zamora F., Zamora F., Zamora F., Zamora F. Chemical Communications; 56 (49): 6704 - 6707. 2020. 10.1039/d0cc02033h. IF: 5.996

Dynamic covalent bonds have been advantageously used to direct the synthesis of crystalline porous covalent organic frameworks (COFs). Unlike the standard synthetic protocols that involve harsh conditions, this work provides a high-yield "one-pot"green synthesis of imine-based COFs in water. Additionally, this aqueous synthesis can be performed under microwave conditions, considerably reducing the reaction time. © The Royal Society of Chemistry.

View abstract
Green synthesis of imine-based covalent organic frameworks in water
Martín-Illán J.Á., Rodríguez-San-Miguel D., Rodríguez-San-Miguel D., Franco C., Imaz I., Maspoch D., Maspoch D., Puigmartí-Luis J., Zamora F., Zamora F., Zamora F., Zamora F. Chemical Communications; 56 (49): 6704 - 6707. 2020. 10.1039/d0cc02033h. IF: 5.996

Dynamic covalent bonds have been advantageously used to direct the synthesis of crystalline porous covalent organic frameworks (COFs). Unlike the standard synthetic protocols that involve harsh conditions, this work provides a high-yield "one-pot"green synthesis of imine-based COFs in water. Additionally, this aqueous synthesis can be performed under microwave conditions, considerably reducing the reaction time. © The Royal Society of Chemistry.

View abstract
MOF-Beads Containing Inorganic Nanoparticles for the Simultaneous Removal of Multiple Heavy Metals from Water
Boix G., Troyano J., Garzón-Tovar L., Camur C., Bermejo N., Yazdi A., Piella J., Bastus N.G., Puntes V.F., Imaz I., Maspoch D. ACS Applied Materials and Interfaces; 12 (9): 10554 - 10562. 2020. 10.1021/acsami.9b23206. IF: 8.758

Pollution of water with heavy metals is a global environmental problem whose impact is especially severe in developing countries. Among water-purification methods, adsorption of heavy metals has proven to be simple, versatile, and cost-effective. However, there is still a need to develop adsorbents with a capacity to remove multiple metal pollutants from the same water sample. Herein, we report the complementary adsorption capacities of metal-organic frameworks (here, UiO-66 and UiO-66-(SH)2) and inorganic nanoparticles (iNPs; here, cerium-oxide NPs) into composite materials. These adsorbents, which are spherical microbeads generated in one step by continuous-flow spray-drying, efficiently and simultaneously remove multiple heavy metals from water, including As(III and V), Cd(II), Cr(III and VI), Cu(II), Pb(II), and Hg(II). We further show that these microbeads can be used as a packing material in a prototype of a continuous-flow water treatment system, in which they retain their metal-removal capacities upon regeneration with a gentle acidic treatment. As proof-of-concept, we evaluated these adsorbents for purification of laboratory water samples prepared to independently recapitulate each of two strongly polluted rivers: the Bone (Indonesia) and Buringanga (Bangladesh) rivers. In both cases, our microbeads reduced the levels of all the metal contaminants to below the corresponding permissible limits established by the World Health Organization (WHO). Moreover, we demonstrated the capacity of these microbeads to lower levels of Cr(VI) in a water sample collected from the Sarno River (Italy). Finally, to create adsorbents that could be magnetically recovered following their use in water purification, we extended our spray-drying technique to simultaneously incorporate two types of iNPs (CeO2 and Fe3O4) into UiO-66-(SH)2, obtaining CeO2/Fe3O4@UiO-66-(SH)2 microbeads that adsorb heavy metals and are magnetically responsive. Copyright © 2020 American Chemical Society.

View abstract
MOF-Beads Containing Inorganic Nanoparticles for the Simultaneous Removal of Multiple Heavy Metals from Water
Boix G., Troyano J., Garzón-Tovar L., Camur C., Bermejo N., Yazdi A., Piella J., Bastus N.G., Puntes V.F., Imaz I., Maspoch D. ACS Applied Materials and Interfaces; 12 (9): 10554 - 10562. 2020. 10.1021/acsami.9b23206. IF: 8.758

Pollution of water with heavy metals is a global environmental problem whose impact is especially severe in developing countries. Among water-purification methods, adsorption of heavy metals has proven to be simple, versatile, and cost-effective. However, there is still a need to develop adsorbents with a capacity to remove multiple metal pollutants from the same water sample. Herein, we report the complementary adsorption capacities of metal-organic frameworks (here, UiO-66 and UiO-66-(SH)2) and inorganic nanoparticles (iNPs; here, cerium-oxide NPs) into composite materials. These adsorbents, which are spherical microbeads generated in one step by continuous-flow spray-drying, efficiently and simultaneously remove multiple heavy metals from water, including As(III and V), Cd(II), Cr(III and VI), Cu(II), Pb(II), and Hg(II). We further show that these microbeads can be used as a packing material in a prototype of a continuous-flow water treatment system, in which they retain their metal-removal capacities upon regeneration with a gentle acidic treatment. As proof-of-concept, we evaluated these adsorbents for purification of laboratory water samples prepared to independently recapitulate each of two strongly polluted rivers: the Bone (Indonesia) and Buringanga (Bangladesh) rivers. In both cases, our microbeads reduced the levels of all the metal contaminants to below the corresponding permissible limits established by the World Health Organization (WHO). Moreover, we demonstrated the capacity of these microbeads to lower levels of Cr(VI) in a water sample collected from the Sarno River (Italy). Finally, to create adsorbents that could be magnetically recovered following their use in water purification, we extended our spray-drying technique to simultaneously incorporate two types of iNPs (CeO2 and Fe3O4) into UiO-66-(SH)2, obtaining CeO2/Fe3O4@UiO-66-(SH)2 microbeads that adsorb heavy metals and are magnetically responsive. Copyright © 2020 American Chemical Society.

View abstract
Molecular Approach for Engineering Interfacial Interactions in Magnetic/Topological Insulator Heterostructures
Cuxart M.G., Valbuena M.A., Robles R., Moreno C., Bonell F., Sauthier G., Imaz I., Xu H., Nistor C., Barla A., Gargiani P., Valvidares M., Maspoch D., Gambardella P., Valenzuela S.O., Mugarza A. ACS Nano; 14 (5): 6285 - 6294. 2020. 10.1021/acsnano.0c02498. IF: 14.588

Controlling interfacial interactions in magnetic/topological insulator heterostructures is a major challenge for the emergence of novel spin-dependent electronic phenomena. As for any rational design of heterostructures that rely on proximity effects, one should ideally retain the overall properties of each component while tuning interactions at the interface. However, in most inorganic interfaces, interactions are too strong, consequently perturbing, and even quenching, both the magnetic moment and the topological surface states at each side of the interface. Here, we show that these properties can be preserved using ligand chemistry to tune the interaction of magnetic ions with the surface states. By depositing Co-based porphyrin and phthalocyanine monolayers on the surface of Bi2Te3 thin films, robust interfaces are formed that preserve undoped topological surface states as well as the pristine magnetic moment of the divalent Co ions. The selected ligands allow us to tune the interfacial hybridization within this weak interaction regime. These results, which are in stark contrast with the observed suppression of the surface state at the first quintuple layer of Bi2Se3 induced by the interaction with Co phthalocyanines, demonstrate the capability of planar metal-organic molecules to span interactions from the strong to the weak limit. © 2020 American Chemical Society.

View abstract
Molecular Approach for Engineering Interfacial Interactions in Magnetic/Topological Insulator Heterostructures
Cuxart M.G., Valbuena M.A., Robles R., Moreno C., Bonell F., Sauthier G., Imaz I., Xu H., Nistor C., Barla A., Gargiani P., Valvidares M., Maspoch D., Gambardella P., Valenzuela S.O., Mugarza A. ACS Nano; 14 (5): 6285 - 6294. 2020. 10.1021/acsnano.0c02498. IF: 14.588

Controlling interfacial interactions in magnetic/topological insulator heterostructures is a major challenge for the emergence of novel spin-dependent electronic phenomena. As for any rational design of heterostructures that rely on proximity effects, one should ideally retain the overall properties of each component while tuning interactions at the interface. However, in most inorganic interfaces, interactions are too strong, consequently perturbing, and even quenching, both the magnetic moment and the topological surface states at each side of the interface. Here, we show that these properties can be preserved using ligand chemistry to tune the interaction of magnetic ions with the surface states. By depositing Co-based porphyrin and phthalocyanine monolayers on the surface of Bi2Te3 thin films, robust interfaces are formed that preserve undoped topological surface states as well as the pristine magnetic moment of the divalent Co ions. The selected ligands allow us to tune the interfacial hybridization within this weak interaction regime. These results, which are in stark contrast with the observed suppression of the surface state at the first quintuple layer of Bi2Se3 induced by the interaction with Co phthalocyanines, demonstrate the capability of planar metal-organic molecules to span interactions from the strong to the weak limit. © 2020 American Chemical Society.

View abstract
Net-Clipping: An Approach to Deduce the Topology of Metal-Organic Frameworks Built with Zigzag Ligands
Ortín-Rubio B., Ghasempour H., Guillerm V., Morsali A., Juanhuix J., Imaz I., Maspoch D., Maspoch D. Journal of the American Chemical Society; 142 (20): 9135 - 9140. 2020. 10.1021/jacs.0c03404. IF: 14.612

Herein we propose a new approach for deducing the topology of metal-organic frameworks (MOFs) assembled from organic ligands of low symmetry, which we call net-clipping. It is based on the construction of nets by rational deconstruction of edge-transitive nets comprising higher-connected molecular building blocks (MBBs). We have applied net-clipping to predict the topologies of MOFs containing zigzag ligands. To this end, we derived 2-connected (2-c) zigzag ligands from 4-c square-like MBBs by first splitting the 4-c nodes into two 3-c nodes and then clipping their two diagonally connecting groups. We demonstrate that, when this approach is applied to the 17 edge-transitive nets containing square-like 4-c MBBs, net-clipping leads to generation of 10 nets with different underlying topologies. Moreover, we report that literature and experimental research corroborate successful implementation of our approach. As proof-of-concept, we employed net-clipping to form three new MOFs built with zigzag ligands, each of which exhibits the deduced topology. © 2020 American Chemical Society.

View abstract
Net-Clipping: An Approach to Deduce the Topology of Metal-Organic Frameworks Built with Zigzag Ligands
Ortín-Rubio B., Ghasempour H., Guillerm V., Morsali A., Juanhuix J., Imaz I., Maspoch D., Maspoch D. Journal of the American Chemical Society; 142 (20): 9135 - 9140. 2020. 10.1021/jacs.0c03404. IF: 14.612

Herein we propose a new approach for deducing the topology of metal-organic frameworks (MOFs) assembled from organic ligands of low symmetry, which we call net-clipping. It is based on the construction of nets by rational deconstruction of edge-transitive nets comprising higher-connected molecular building blocks (MBBs). We have applied net-clipping to predict the topologies of MOFs containing zigzag ligands. To this end, we derived 2-connected (2-c) zigzag ligands from 4-c square-like MBBs by first splitting the 4-c nodes into two 3-c nodes and then clipping their two diagonally connecting groups. We demonstrate that, when this approach is applied to the 17 edge-transitive nets containing square-like 4-c MBBs, net-clipping leads to generation of 10 nets with different underlying topologies. Moreover, we report that literature and experimental research corroborate successful implementation of our approach. As proof-of-concept, we employed net-clipping to form three new MOFs built with zigzag ligands, each of which exhibits the deduced topology. © 2020 American Chemical Society.

View abstract
Spray-Drying Synthesis of MOFs, COFs, and Related Composites
Troyano J., Çamur C., Garzón-Tovar L., Carné-Sánchez A., Imaz I., Maspoch D., Maspoch D. Accounts of Chemical Research; 53 (6): 1206 - 1217. 2020. 10.1021/acs.accounts.0c00133. IF: 20.832

ConspectusMetal-organic frameworks (MOFs) and covalent organic frameworks (COFs) are among the most attractive porous materials today. They exhibit outstanding porosity for countless applications such as gas storage, CO2 capture, gas separation, sensing, drug delivery, and catalysis. Moreover, researchers have recently begun to combine MOFs or COFs with other functional materials to obtain composites that boast the respective strengths, and mitigate the respective weaknesses, of each component, enabling enhanced performance in many of the aforementioned applications. Accordingly, development of methods for fabrication of MOFs, COFs, and related composites is important for facilitating adoption of these materials in industry. One promising synthetic technique is spray-drying, which is already well-integrated in manufacturing processes for diverse sectors. It enables rapid, continuous and scalable production of dry microspherical powders in a single step, leading to lower fabrication costs and shorter production times compared to traditional methods.In this Account, we outline our ongoing work on spray-drying synthesis of crystalline porous MOFs, COFs, and related composites. Versatile and tunable, spray-drying can be adapted to perform reactions involving coordination and covalent chemistry for the synthesis of micrometer spherical beads/superstructures of MOFs and COFs. Likewise, MOF- and COF-based composites can be synthesized using similar conditions as those for pure MOFs or COFs, through the simple introduction of additional functional materials into the feed precursor solution or colloid. Interestingly, spray-drying can also be done in water, thus providing the basis for its use as a scalable green method for industrial fabrication of these materials. To date, spray-drying has already been scaled up for pilot production (kilogram scale) of MOFs. © 2020 American Chemical Society.

View abstract
Spray-Drying Synthesis of MOFs, COFs, and Related Composites
Troyano J., Çamur C., Garzón-Tovar L., Carné-Sánchez A., Imaz I., Maspoch D., Maspoch D. Accounts of Chemical Research; 53 (6): 1206 - 1217. 2020. 10.1021/acs.accounts.0c00133. IF: 20.832

ConspectusMetal-organic frameworks (MOFs) and covalent organic frameworks (COFs) are among the most attractive porous materials today. They exhibit outstanding porosity for countless applications such as gas storage, CO2 capture, gas separation, sensing, drug delivery, and catalysis. Moreover, researchers have recently begun to combine MOFs or COFs with other functional materials to obtain composites that boast the respective strengths, and mitigate the respective weaknesses, of each component, enabling enhanced performance in many of the aforementioned applications. Accordingly, development of methods for fabrication of MOFs, COFs, and related composites is important for facilitating adoption of these materials in industry. One promising synthetic technique is spray-drying, which is already well-integrated in manufacturing processes for diverse sectors. It enables rapid, continuous and scalable production of dry microspherical powders in a single step, leading to lower fabrication costs and shorter production times compared to traditional methods.In this Account, we outline our ongoing work on spray-drying synthesis of crystalline porous MOFs, COFs, and related composites. Versatile and tunable, spray-drying can be adapted to perform reactions involving coordination and covalent chemistry for the synthesis of micrometer spherical beads/superstructures of MOFs and COFs. Likewise, MOF- and COF-based composites can be synthesized using similar conditions as those for pure MOFs or COFs, through the simple introduction of additional functional materials into the feed precursor solution or colloid. Interestingly, spray-drying can also be done in water, thus providing the basis for its use as a scalable green method for industrial fabrication of these materials. To date, spray-drying has already been scaled up for pilot production (kilogram scale) of MOFs. © 2020 American Chemical Society.

View abstract
Structural Deterioration of Well-Faceted MOFs upon H2S Exposure and Its Effect in the Adsorption Performance
Reljic S., Broto-Ribas A., Cuadrado-Collados C., Jardim E.O., Maspoch D., Imaz I., Silvestre-Albero J. Chemistry - A European Journal; 26 (71): 17110 - 17119. 2020. 10.1002/chem.202002473. IF: 4.857

The structural deterioration of archetypical, well-faceted metal–organic frameworks (MOFs) has been evaluated upon exposure to an acidic environment (H2S). Experimental results show that the structural damage highly depends on the nature of the hybrid network (e.g., softness of the metal ions, hydrophilic properties, among others) and the crystallographic orientation of the exposed facets. Microscopy images show that HKUST-1 with well-defined octahedral (111) facets is completely deteriorated, ZIF-8 with preferentially exposed (110) facets exhibits a large external deterioration with the development of holes or cavities in the mesoporous range, whereas UiO-66-NH2 with (111) exposed facets, and PCN-250 with (100) facets does not reflect any sign of surface damage. Despite the selectivity in the external deterioration, X-ray diffraction and gas adsorption measurements confirm that indeed all MOFs suffer an important internal deterioration, these effects being more severe for MOFs based on softer cations (e.g., Cu-based HKUST-1 and Fe-based PCN-250). These structural changes have inevitable important effects in the final adsorption performance for CO2 and CH4 at low and high pressures. © 2020 Wiley-VCH GmbH

View abstract
Structural Deterioration of Well-Faceted MOFs upon H2S Exposure and Its Effect in the Adsorption Performance
Reljic S., Broto-Ribas A., Cuadrado-Collados C., Jardim E.O., Maspoch D., Imaz I., Silvestre-Albero J. Chemistry - A European Journal; 26 (71): 17110 - 17119. 2020. 10.1002/chem.202002473. IF: 4.857

The structural deterioration of archetypical, well-faceted metal–organic frameworks (MOFs) has been evaluated upon exposure to an acidic environment (H2S). Experimental results show that the structural damage highly depends on the nature of the hybrid network (e.g., softness of the metal ions, hydrophilic properties, among others) and the crystallographic orientation of the exposed facets. Microscopy images show that HKUST-1 with well-defined octahedral (111) facets is completely deteriorated, ZIF-8 with preferentially exposed (110) facets exhibits a large external deterioration with the development of holes or cavities in the mesoporous range, whereas UiO-66-NH2 with (111) exposed facets, and PCN-250 with (100) facets does not reflect any sign of surface damage. Despite the selectivity in the external deterioration, X-ray diffraction and gas adsorption measurements confirm that indeed all MOFs suffer an important internal deterioration, these effects being more severe for MOFs based on softer cations (e.g., Cu-based HKUST-1 and Fe-based PCN-250). These structural changes have inevitable important effects in the final adsorption performance for CO2 and CH4 at low and high pressures. © 2020 Wiley-VCH GmbH

View abstract
Supramolecular Fullerene Sponges as Catalytic Masks for Regioselective Functionalization of C60
Fuertes-Espinosa C., García-Simón C., Pujals M., Garcia-Borràs M., Gómez L., Parella T., Juanhuix J., Imaz I., Maspoch D., Costas M., Ribas X. Chem; 6 (1): 169 - 186. 2020. 10.1016/j.chempr.2019.10.010. IF: 19.375

Isomer-pure poly-functionalized fullerenes are required to boost the development of fullerene chemistry in all fields. On a general basis, multi-adduct mixtures with uncontrolled regioselectivity are obtained, and the use of chromatographic purification is prohibitively costly and time consuming, especially in the production of solar cells. Single-isomer poly-functionalized fullerenes are only accessible via stoichiometric, multistep paths entailing protecting-unprotecting sequences. Herein, a nanocapsule is used as a supramolecular tetragonal prismatic mask to exert full control on the reactivity and the equatorial regioselectivity of Bingel-Hirsch cyclopropanation reactions of a confined C60 guest. Thus, equatorial bis-, tris-, and tetrakis-C60 homo-adducts are exclusively obtained in a stepwise manner. Furthermore, isomer-pure equatorial hetero-tetrakis-adducts or hetero-Th-hexakis-adducts are synthesized at will in one-pot synthesis for the first time. This work provides a synthetically valuable path to produce a plethora of new pure-isomer poly-functionalized C60-based compounds as candidates for testing in solar cell devices and biomedical applications. Video Abstract: The supramolecular mask protocol is a significant step forward for the regioselective functionalization of fullerenes. The exquisite ability to form pure-isomer poly-functionalized C60 adducts, overcoming tedious and non-practical chromatographic separations, allows for their direct testing in solar cell prototypes. Furthermore, the supramolecular mask strategy can be applied to C70 or higher fullerenes, opening a plethora of poly-functionalized fullerene derivatives to be synthesized and tested. Moreover, apart from the nucleophilic cyclopropanations reported herein, the protocol is currently being expanded to Diels-Alder (DA), 1,3-dipolar cycloadditions and PC60BM-type cyclopropanations, thus enabling a variety of regioselective functionalization reactions. This supramolecular mask strategy can help the discovery of the next generation of improved solar cells (organic or perovskite based) or new drug candidates. An unprecedented and straightforward supramolecular mask strategy to prepare exclusively equatorial bis-, tris-, and tetrakis-cyclopropanated-C60 Bingel-Hirsch derivatives is reported. By taking advantage of the high affinity for fullerene of tetragonal prismatic supramolecular cages, a highly stable C60⊂1a·(BArF)8 host-guest complex is submitted to Bingel-Hirsch cyclopropanation reaction conditions. Regioselectivity is strictly dictated by the four cross-shaped apertures of the nanocapsule in a controlled fashion. Moreover, stepwise-cyclopropanated adducts up to tetrakis additions are obtained in excellent yields and purities. © 2019 Elsevier Inc.

View abstract
Supramolecular Fullerene Sponges as Catalytic Masks for Regioselective Functionalization of C60
Fuertes-Espinosa C., García-Simón C., Pujals M., Garcia-Borràs M., Gómez L., Parella T., Juanhuix J., Imaz I., Maspoch D., Costas M., Ribas X. Chem; 6 (1): 169 - 186. 2020. 10.1016/j.chempr.2019.10.010. IF: 19.375

Isomer-pure poly-functionalized fullerenes are required to boost the development of fullerene chemistry in all fields. On a general basis, multi-adduct mixtures with uncontrolled regioselectivity are obtained, and the use of chromatographic purification is prohibitively costly and time consuming, especially in the production of solar cells. Single-isomer poly-functionalized fullerenes are only accessible via stoichiometric, multistep paths entailing protecting-unprotecting sequences. Herein, a nanocapsule is used as a supramolecular tetragonal prismatic mask to exert full control on the reactivity and the equatorial regioselectivity of Bingel-Hirsch cyclopropanation reactions of a confined C60 guest. Thus, equatorial bis-, tris-, and tetrakis-C60 homo-adducts are exclusively obtained in a stepwise manner. Furthermore, isomer-pure equatorial hetero-tetrakis-adducts or hetero-Th-hexakis-adducts are synthesized at will in one-pot synthesis for the first time. This work provides a synthetically valuable path to produce a plethora of new pure-isomer poly-functionalized C60-based compounds as candidates for testing in solar cell devices and biomedical applications. Video Abstract: The supramolecular mask protocol is a significant step forward for the regioselective functionalization of fullerenes. The exquisite ability to form pure-isomer poly-functionalized C60 adducts, overcoming tedious and non-practical chromatographic separations, allows for their direct testing in solar cell prototypes. Furthermore, the supramolecular mask strategy can be applied to C70 or higher fullerenes, opening a plethora of poly-functionalized fullerene derivatives to be synthesized and tested. Moreover, apart from the nucleophilic cyclopropanations reported herein, the protocol is currently being expanded to Diels-Alder (DA), 1,3-dipolar cycloadditions and PC60BM-type cyclopropanations, thus enabling a variety of regioselective functionalization reactions. This supramolecular mask strategy can help the discovery of the next generation of improved solar cells (organic or perovskite based) or new drug candidates. An unprecedented and straightforward supramolecular mask strategy to prepare exclusively equatorial bis-, tris-, and tetrakis-cyclopropanated-C60 Bingel-Hirsch derivatives is reported. By taking advantage of the high affinity for fullerene of tetragonal prismatic supramolecular cages, a highly stable C60⊂1a·(BArF)8 host-guest complex is submitted to Bingel-Hirsch cyclopropanation reaction conditions. Regioselectivity is strictly dictated by the four cross-shaped apertures of the nanocapsule in a controlled fashion. Moreover, stepwise-cyclopropanated adducts up to tetrakis additions are obtained in excellent yields and purities. © 2019 Elsevier Inc.

View abstract

2019

A MOF@COF Composite with Enhanced Uptake through Interfacial Pore Generation
Garzón-Tovar L., Pérez-Carvajal J., Yazdi A., Hernández-Muñoz J., Tarazona P., Imaz I., Zamora F., Maspoch D. Angewandte Chemie - International Edition; 58 (28): 9512 - 9516. 2019. 10.1002/anie.201904766. IF: 12.257

Herein, we describe a new class of porous composites comprising metal–organic framework (MOF) crystals confined in single spherical matrices made of packed covalent-organic framework (COF) nanocrystals. These MOF@COF composites are synthesized through a two-step method of spray-drying and subsequent amorphous (imine-based polymer)-to-crystalline (imine-based COF) transformation. This transformation around the MOF crystals generates micro- and mesopores at the MOF/COF interface that provide far superior porosity compared to that of the constituent MOF and COF components added together. We report that water sorption in these new pores occurs within the same pressure window as in the COF pores. Our new MOF@COF composites, with their additional pores at the MOF/COF interface, should have implications for the development of new composites. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
A MOF@COF Composite with Enhanced Uptake through Interfacial Pore Generation
Garzón-Tovar L., Pérez-Carvajal J., Yazdi A., Hernández-Muñoz J., Tarazona P., Imaz I., Zamora F., Maspoch D. Angewandte Chemie - International Edition; 58 (28): 9512 - 9516. 2019. 10.1002/anie.201904766. IF: 12.257

Herein, we describe a new class of porous composites comprising metal–organic framework (MOF) crystals confined in single spherical matrices made of packed covalent-organic framework (COF) nanocrystals. These MOF@COF composites are synthesized through a two-step method of spray-drying and subsequent amorphous (imine-based polymer)-to-crystalline (imine-based COF) transformation. This transformation around the MOF crystals generates micro- and mesopores at the MOF/COF interface that provide far superior porosity compared to that of the constituent MOF and COF components added together. We report that water sorption in these new pores occurs within the same pressure window as in the COF pores. Our new MOF@COF composites, with their additional pores at the MOF/COF interface, should have implications for the development of new composites. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
A MOF@COF Composite with Enhanced Uptake through Interfacial Pore Generation (2)
Garzón?Tovar, Luis; Pérez?Carvajal, Javier; Yazdi, Amirali; Hernández?Muñoz, Jose; Tarazona, Pedro; Imaz, Inhar; Zamora, Félix; Maspoch, Daniel Angewandte Chemie; 131 (28): 9612 - 9616. 2019. 10.1002/ange.201904766.
A MOF@COF Composite with Enhanced Uptake through Interfacial Pore Generation (2)
Garzón?Tovar, Luis; Pérez?Carvajal, Javier; Yazdi, Amirali; Hernández?Muñoz, Jose; Tarazona, Pedro; Imaz, Inhar; Zamora, Félix; Maspoch, Daniel Angewandte Chemie; 131 (28): 9612 - 9616. 2019. 10.1002/ange.201904766.
Colloidal metal-organic framework particles: The pioneering case of ZIF-8
Troyano J., Carné-Sánchez A., Avci C., Imaz I., Maspoch D. Chemical Society Reviews; 48 (23): 5534 - 5546. 2019. 10.1039/c9cs00472f. IF: 40.443

The production of metal-organic frameworks (MOFs) in the form of colloids has brought a paradigm shift in the design of new functional porous materials. Along with their intrinsic interest as porous solids, and contrary to their bulk powder counterparts, colloidal MOF particles can additionally be dispersed, shaped, functionalized, transformed and assembled in a controlled manner, conferring them further properties and applications. In this regard, zeolitic imidazolate framework-8 (ZIF-8) has become a pioneering MOF constituent of colloidal science. Today, the understanding of the role of synthetic parameters, learned after one decade of research, enables the production of monodisperse colloidal ZIF-8 particles with tunable dimensions and morphologies, offering the opportunity to develop new functional materials and composites with novel and promising functionalities. This tutorial review provides a useful guide to prepare ZIF-8 in its colloidal form, covering the published studies on the synthesis of homogeneous ZIF-8 particles with controlled size and shape. In addition, we present the most relevant advances in the development of colloidal ZIF-8 hybrid single-particles, reflecting the great potential and rapid development of this interdisciplinary research field. Finally, we highlight how formulation of ZIF-8 as colloids has led to the emergence of novel physicochemical phenomena that are useful for practical applications. This review aims at promoting the development of MOFs as colloids, taking ZIF-8 as a pioneering and successful case that clearly shows the benefits of bridging MOF chemistry and colloidal science. This journal is © The Royal Society of Chemistry.

View abstract
Colloidal metal-organic framework particles: The pioneering case of ZIF-8
Troyano J., Carné-Sánchez A., Avci C., Imaz I., Maspoch D. Chemical Society Reviews; 48 (23): 5534 - 5546. 2019. 10.1039/c9cs00472f. IF: 40.443

The production of metal-organic frameworks (MOFs) in the form of colloids has brought a paradigm shift in the design of new functional porous materials. Along with their intrinsic interest as porous solids, and contrary to their bulk powder counterparts, colloidal MOF particles can additionally be dispersed, shaped, functionalized, transformed and assembled in a controlled manner, conferring them further properties and applications. In this regard, zeolitic imidazolate framework-8 (ZIF-8) has become a pioneering MOF constituent of colloidal science. Today, the understanding of the role of synthetic parameters, learned after one decade of research, enables the production of monodisperse colloidal ZIF-8 particles with tunable dimensions and morphologies, offering the opportunity to develop new functional materials and composites with novel and promising functionalities. This tutorial review provides a useful guide to prepare ZIF-8 in its colloidal form, covering the published studies on the synthesis of homogeneous ZIF-8 particles with controlled size and shape. In addition, we present the most relevant advances in the development of colloidal ZIF-8 hybrid single-particles, reflecting the great potential and rapid development of this interdisciplinary research field. Finally, we highlight how formulation of ZIF-8 as colloids has led to the emergence of novel physicochemical phenomena that are useful for practical applications. This review aims at promoting the development of MOFs as colloids, taking ZIF-8 as a pioneering and successful case that clearly shows the benefits of bridging MOF chemistry and colloidal science. This journal is © The Royal Society of Chemistry.

View abstract
Highly Strained, Radially ?-Conjugated Porphyrinylene Nanohoops
Xu Y., Gsänger S., Minameyer M.B., Imaz I., Maspoch D., Shyshov O., Schwer F., Ribas X., Drewello T., Meyer B., Von Delius M. Journal of the American Chemical Society; 141 (46): 18500 - 18507. 2019. 10.1021/jacs.9b08584. IF: 14.695

Small ?-conjugated nanohoops are difficult to prepare, but offer an excellent platform for studying the interplay between strain and optoelectronic properties, and, increasingly, these shape-persistent macrocycles find uses in host-guest chemistry and self-assembly. We report the synthesis of a new family of radially ?-conjugated porphyrinylene/phenylene nanohoops. The strain energy in the smallest nanohoop [2]CPT is approximately 54 kcal mol-1, which results in a narrowed HOMO-LUMO gap and a red shift in the visible part of the absorption spectrum. Because of its high degree of preorganization and a diameter of ca. 13 Å, [2]CPT was found to accommodate C60 with a binding affinity exceeding 108 M-1 despite the fullerene not fully entering the cavity of the host (X-ray crystallography). Moreover, the ?-extended nanohoops [2]CPTN, [3]CPTN, and [3]CPTA (N for 1,4-naphthyl; A for 9,10-anthracenyl) have been prepared using the same strategy, and [2]CPTN has been shown to bind C70 5 times more strongly than [2]CPT. Our failed synthesis of [2]CPTA highlights a limitation of the experimental approach most commonly used to prepare strained nanohoops, because in this particular case the sum of aromatization energies no longer outweighs the buildup of ring strain in the final reaction step (DFT calculations). These results indicate that forcing ring strain onto organic semiconductors is a viable strategy to fundamentally influence both optoelectronic and supramolecular properties. © 2019 American Chemical Society.

View abstract
Highly Strained, Radially ?-Conjugated Porphyrinylene Nanohoops
Xu Y., Gsänger S., Minameyer M.B., Imaz I., Maspoch D., Shyshov O., Schwer F., Ribas X., Drewello T., Meyer B., Von Delius M. Journal of the American Chemical Society; 141 (46): 18500 - 18507. 2019. 10.1021/jacs.9b08584. IF: 14.695

Small ?-conjugated nanohoops are difficult to prepare, but offer an excellent platform for studying the interplay between strain and optoelectronic properties, and, increasingly, these shape-persistent macrocycles find uses in host-guest chemistry and self-assembly. We report the synthesis of a new family of radially ?-conjugated porphyrinylene/phenylene nanohoops. The strain energy in the smallest nanohoop [2]CPT is approximately 54 kcal mol-1, which results in a narrowed HOMO-LUMO gap and a red shift in the visible part of the absorption spectrum. Because of its high degree of preorganization and a diameter of ca. 13 Å, [2]CPT was found to accommodate C60 with a binding affinity exceeding 108 M-1 despite the fullerene not fully entering the cavity of the host (X-ray crystallography). Moreover, the ?-extended nanohoops [2]CPTN, [3]CPTN, and [3]CPTA (N for 1,4-naphthyl; A for 9,10-anthracenyl) have been prepared using the same strategy, and [2]CPTN has been shown to bind C70 5 times more strongly than [2]CPT. Our failed synthesis of [2]CPTA highlights a limitation of the experimental approach most commonly used to prepare strained nanohoops, because in this particular case the sum of aromatization energies no longer outweighs the buildup of ring strain in the final reaction step (DFT calculations). These results indicate that forcing ring strain onto organic semiconductors is a viable strategy to fundamentally influence both optoelectronic and supramolecular properties. © 2019 American Chemical Society.

View abstract
Phase Transfer of Rhodium(II)-Based Metal-Organic Polyhedra Bearing Coordinatively Bound Cargo Enables Molecular Separation
Grancha T., Carné-Sánchez A., Hernández-López L., Albalad J., Imaz I., Juanhuix J., Maspoch D. Journal of the American Chemical Society; 141 (45): 18349 - 18355. 2019. 10.1021/jacs.9b10403. IF: 14.695

The transfer of nanoparticles between immiscible phases can be driven by externally triggered changes in their surface composition. Interestingly, phase transfers can enhance the processing of nanoparticles and enable their use as vehicles for transporting molecular cargo. Herein we report extension of such phase transfers to encompass porous metal-organic polyhedra (MOPs). We report that a hydroxyl-functionalized, cuboctahedral Rh(II)-based MOP can be transferred between immiscible phases by pH changes or by cation-exchange reactions. We demonstrate use of this MOP to transport coordinatively bound cargo between immiscible layers, including into solvents in which the cargo is insoluble. As proof-of-concept that our phase-transfer approach could be used in chemical separation, we employed Rh(II)-based MOPs to separate a challenging mixture of structurally similar cyclic aliphatic (tetrahydrothiophene) and aromatic (thiophene) compounds. We anticipate that transport of coordinatively bound molecules will open new avenues for molecular separation based on the relative coordination affinity that the molecules have for the Rh(II) sites of MOP. Copyright © 2019 American Chemical Society.

View abstract
Phase Transfer of Rhodium(II)-Based Metal-Organic Polyhedra Bearing Coordinatively Bound Cargo Enables Molecular Separation
Grancha T., Carné-Sánchez A., Hernández-López L., Albalad J., Imaz I., Juanhuix J., Maspoch D. Journal of the American Chemical Society; 141 (45): 18349 - 18355. 2019. 10.1021/jacs.9b10403. IF: 14.695

The transfer of nanoparticles between immiscible phases can be driven by externally triggered changes in their surface composition. Interestingly, phase transfers can enhance the processing of nanoparticles and enable their use as vehicles for transporting molecular cargo. Herein we report extension of such phase transfers to encompass porous metal-organic polyhedra (MOPs). We report that a hydroxyl-functionalized, cuboctahedral Rh(II)-based MOP can be transferred between immiscible phases by pH changes or by cation-exchange reactions. We demonstrate use of this MOP to transport coordinatively bound cargo between immiscible layers, including into solvents in which the cargo is insoluble. As proof-of-concept that our phase-transfer approach could be used in chemical separation, we employed Rh(II)-based MOPs to separate a challenging mixture of structurally similar cyclic aliphatic (tetrahydrothiophene) and aromatic (thiophene) compounds. We anticipate that transport of coordinatively bound molecules will open new avenues for molecular separation based on the relative coordination affinity that the molecules have for the Rh(II) sites of MOP. Copyright © 2019 American Chemical Society.

View abstract
Postsynthetic Covalent and Coordination Functionalization of Rhodium(II)-Based Metal-Organic Polyhedra
Carné-Sánchez A., Albalad J., Grancha T., Imaz I., Juanhuix J., Larpent P., Furukawa S., Maspoch D. Journal of the American Chemical Society; 141 (9): 4094 - 4102. 2019. 10.1021/jacs.8b13593. IF: 14.695

Metal-organic polyhedra (MOP) are ultrasmall (typically 1-4 nm) porous coordination cages made from the self-assembly of metal ions and organic linkers and are amenable to the chemical functionalization of its periphery; however, it has been challenging to implement postsynthetic functionalization due to their chemical instability. Herein, we report the use of coordination chemistries and covalent chemistries to postsynthetically functionalize the external surface of â‰2.5 nm stable Rh(II)-based cuboctahedra through their Rh-Rh paddlewheel units or organic linkers, respectively. We demonstrate that 12 N-donor ligands, including amino acids, can be coordinated on the periphery of Rh-MOPs. We used this reactivity to introduce new functionalities (e.g., chirality) to the MOPs and to tune their hydrophilic/hydrophobic characteristics, which allowed us to modulate their solubility in diverse solvents such as dichloromethane and water. We also demonstrate that all 24 organic linkers can be postsynthetically functionalized with esters via covalent chemistry. In addition, we anticipate that these two types of postsynthetic reactions can be combined to yield doubly functionalized Rh-MOPs, in which a total of 36 new functional molecules can be incorporated on their surfaces. Likewise, these chemistries could be synergistically combined to enable covalent functionalization of MOPs through new linkages such as ethers. We believe that both reported postsynthetic pathways can potentially be used to engineer Rh-MOPs as scaffolds for applications in delivery, sorption, and catalysis. © Copyright 2019 American Chemical Society.

View abstract
Postsynthetic Covalent and Coordination Functionalization of Rhodium(II)-Based Metal-Organic Polyhedra
Carné-Sánchez A., Albalad J., Grancha T., Imaz I., Juanhuix J., Larpent P., Furukawa S., Maspoch D. Journal of the American Chemical Society; 141 (9): 4094 - 4102. 2019. 10.1021/jacs.8b13593. IF: 14.695

Metal-organic polyhedra (MOP) are ultrasmall (typically 1-4 nm) porous coordination cages made from the self-assembly of metal ions and organic linkers and are amenable to the chemical functionalization of its periphery; however, it has been challenging to implement postsynthetic functionalization due to their chemical instability. Herein, we report the use of coordination chemistries and covalent chemistries to postsynthetically functionalize the external surface of â‰2.5 nm stable Rh(II)-based cuboctahedra through their Rh-Rh paddlewheel units or organic linkers, respectively. We demonstrate that 12 N-donor ligands, including amino acids, can be coordinated on the periphery of Rh-MOPs. We used this reactivity to introduce new functionalities (e.g., chirality) to the MOPs and to tune their hydrophilic/hydrophobic characteristics, which allowed us to modulate their solubility in diverse solvents such as dichloromethane and water. We also demonstrate that all 24 organic linkers can be postsynthetically functionalized with esters via covalent chemistry. In addition, we anticipate that these two types of postsynthetic reactions can be combined to yield doubly functionalized Rh-MOPs, in which a total of 36 new functional molecules can be incorporated on their surfaces. Likewise, these chemistries could be synergistically combined to enable covalent functionalization of MOPs through new linkages such as ethers. We believe that both reported postsynthetic pathways can potentially be used to engineer Rh-MOPs as scaffolds for applications in delivery, sorption, and catalysis. © Copyright 2019 American Chemical Society.

View abstract
Size-selective encapsulation of C 60 and C 60 -derivatives within an adaptable naphthalene-based tetragonal prismatic supramolecular nanocapsule
García-Simón C., Monferrer A., Garcia-Borràs M., Imaz I., Maspoch D., Costas M., Ribas X. Chemical Communications; 55 (6): 798 - 801. 2019. 10.1039/c8cc07886f. IF: 6.164

A novel naphthalene-based 5·(BArF) 8 capsule allows for the size-selective inclusion of C 60 from fullerene mixtures. Its size selectivity towards C 60 has been rationalized by its dynamic adaptability in solution that has been investigated by molecular dynamics. Additionally, 5·(BArF) 8 encapsulates C 60 -derivatives such as C 60 -PCBM and N-methylpyrrolidine-C 60 . The latter can be separated from C 60 since 5·(BArF) 8 displays distinct affinity for them. © The Royal Society of Chemistry.

View abstract
Size-selective encapsulation of C 60 and C 60 -derivatives within an adaptable naphthalene-based tetragonal prismatic supramolecular nanocapsule
García-Simón C., Monferrer A., Garcia-Borràs M., Imaz I., Maspoch D., Costas M., Ribas X. Chemical Communications; 55 (6): 798 - 801. 2019. 10.1039/c8cc07886f. IF: 6.164

A novel naphthalene-based 5·(BArF) 8 capsule allows for the size-selective inclusion of C 60 from fullerene mixtures. Its size selectivity towards C 60 has been rationalized by its dynamic adaptability in solution that has been investigated by molecular dynamics. Additionally, 5·(BArF) 8 encapsulates C 60 -derivatives such as C 60 -PCBM and N-methylpyrrolidine-C 60 . The latter can be separated from C 60 since 5·(BArF) 8 displays distinct affinity for them. © The Royal Society of Chemistry.

View abstract
Switching acidic and basic catalysis through supramolecular functionalization in a porous 3D covalent imine-based material
Luis-Barrerra J., Cano R., Imani-Shakibaei G., Heras-Domingo J., Pérez-Carvajal J., Imaz I., Maspoch D., Solans-Monfort X., Alemán J., Mas-Ballesté R. Catalysis Science and Technology; 9 (21): 6007 - 6014. 2019. 10.1039/c9cy01527b. IF: 5.726

Non-covalent inclusion of small acid and base molecules (CH3COOH and NEt3) in an imine structure based on micrometre COF-300 crystals and amorphous nanoparticles results in the facile modulation of their acid-base properties. Such a strategy results in the triggering of acidic/basic catalytic activity of the otherwise inactive materials towards ring-opening epoxide and Knoevenagel condensation reactions. For both reactions, amorphous nanoparticles are better catalysts than micrometre crystals as they exhibit a higher external surface area. The found activities and stability of this supramolecular functionalization are modulated by confinement effects, which are rationalized with the help of DFT calculations. All results obtained suggest that the reactions catalysed by these functionalized materials occur confined to pores closer to the material surface, which makes size-discrimination phenomena possible, and explains the major activity of the nanoparticulated material. © The Royal Society of Chemistry 2019.

View abstract
Switching acidic and basic catalysis through supramolecular functionalization in a porous 3D covalent imine-based material
Luis-Barrerra J., Cano R., Imani-Shakibaei G., Heras-Domingo J., Pérez-Carvajal J., Imaz I., Maspoch D., Solans-Monfort X., Alemán J., Mas-Ballesté R. Catalysis Science and Technology; 9 (21): 6007 - 6014. 2019. 10.1039/c9cy01527b. IF: 5.726

Non-covalent inclusion of small acid and base molecules (CH3COOH and NEt3) in an imine structure based on micrometre COF-300 crystals and amorphous nanoparticles results in the facile modulation of their acid-base properties. Such a strategy results in the triggering of acidic/basic catalytic activity of the otherwise inactive materials towards ring-opening epoxide and Knoevenagel condensation reactions. For both reactions, amorphous nanoparticles are better catalysts than micrometre crystals as they exhibit a higher external surface area. The found activities and stability of this supramolecular functionalization are modulated by confinement effects, which are rationalized with the help of DFT calculations. All results obtained suggest that the reactions catalysed by these functionalized materials occur confined to pores closer to the material surface, which makes size-discrimination phenomena possible, and explains the major activity of the nanoparticulated material. © The Royal Society of Chemistry 2019.

View abstract
Template-Free, Surfactant-Mediated Orientation of Self-Assembled Supercrystals of Metal–Organic Framework Particles
Avci C., Liu Y., Pariente J.A., Blanco A., Lopez C., Imaz I., Maspoch D. Small; 15 (31, 1902520) 2019. 10.1002/smll.201902520. IF: 10.856

Mesoscale self-assembly of particles into supercrystals is important for the design of functional materials such as photonic and plasmonic crystals. However, while much progress has been made in self-assembling supercrystals adopting diverse lattices and using different types of particles, controlling their growth orientation on surfaces has received limited success. Most of the latter orientation control has been achieved via templating methods in which lithographic processes are used to form a patterned surface that acts as a template for particle assembly. Herein, a template-free method to self-assemble (111)-, (100)-, and (110)-oriented face-centered cubic supercrystals of the metal–organic framework ZIF-8 particles by adjusting the amount of surfactant (cetyltrimethylammonium bromide) used is described. It is shown that these supercrystals behave as photonic crystals whose properties depend on their growth orientation. This control on the orientation of the supercrystals dictates the orientation of the composing porous particles that might ultimately facilitate pore orientation on surfaces for designing membranes and sensors. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Template-Free, Surfactant-Mediated Orientation of Self-Assembled Supercrystals of Metal–Organic Framework Particles
Avci C., Liu Y., Pariente J.A., Blanco A., Lopez C., Imaz I., Maspoch D. Small; 15 (31, 1902520) 2019. 10.1002/smll.201902520. IF: 10.856

Mesoscale self-assembly of particles into supercrystals is important for the design of functional materials such as photonic and plasmonic crystals. However, while much progress has been made in self-assembling supercrystals adopting diverse lattices and using different types of particles, controlling their growth orientation on surfaces has received limited success. Most of the latter orientation control has been achieved via templating methods in which lithographic processes are used to form a patterned surface that acts as a template for particle assembly. Herein, a template-free method to self-assemble (111)-, (100)-, and (110)-oriented face-centered cubic supercrystals of the metal–organic framework ZIF-8 particles by adjusting the amount of surfactant (cetyltrimethylammonium bromide) used is described. It is shown that these supercrystals behave as photonic crystals whose properties depend on their growth orientation. This control on the orientation of the supercrystals dictates the orientation of the composing porous particles that might ultimately facilitate pore orientation on surfaces for designing membranes and sensors. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
The Imine-Based COF TpPa-1 as an Efficient Cooling Adsorbent That Can Be Regenerated by Heat or Light
Pérez-Carvajal J., Boix G., Imaz I., Maspoch D. Advanced Energy Materials; 9 (39, 1901535) 2019. 10.1002/aenm.201901535. IF: 24.884

Adsorption-based cooling systems, which can be driven by waste heat and solar energy, are promising alternatives to conventional, compression-based cooling systems, as they demand less energy and emit less CO2. The performance of adsorption-based cooling systems relates directly to the performance of the working pairs (sorbent–water). Accordingly, improvement of these systems relies on the continual discovery of new sorbents that enable greater mass exchange while requiring less energy for regeneration. Here, it is proposed that covalent-organic frameworks (COFs) can replace traditional sorbents for adsorption-based cooling. In tests mimicking standard operating conditions for industry, the imine-based COF TpPa-1 exhibits a regeneration temperature below 65 °C and a cooling coefficient of performance of 0.77 – values which are comparable to those reported for the best metal–organic framework sorbents described to date. Moreover, TpPa-1 exhibits a photothermal effect and can be regenerated by visible light, thereby opening the possibility for its use in solar-driven cooling. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
The Imine-Based COF TpPa-1 as an Efficient Cooling Adsorbent That Can Be Regenerated by Heat or Light
Pérez-Carvajal J., Boix G., Imaz I., Maspoch D. Advanced Energy Materials; 9 (39, 1901535) 2019. 10.1002/aenm.201901535. IF: 24.884

Adsorption-based cooling systems, which can be driven by waste heat and solar energy, are promising alternatives to conventional, compression-based cooling systems, as they demand less energy and emit less CO2. The performance of adsorption-based cooling systems relates directly to the performance of the working pairs (sorbent–water). Accordingly, improvement of these systems relies on the continual discovery of new sorbents that enable greater mass exchange while requiring less energy for regeneration. Here, it is proposed that covalent-organic frameworks (COFs) can replace traditional sorbents for adsorption-based cooling. In tests mimicking standard operating conditions for industry, the imine-based COF TpPa-1 exhibits a regeneration temperature below 65 °C and a cooling coefficient of performance of 0.77 – values which are comparable to those reported for the best metal–organic framework sorbents described to date. Moreover, TpPa-1 exhibits a photothermal effect and can be regenerated by visible light, thereby opening the possibility for its use in solar-driven cooling. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Tuning the supramolecular isomerism of MOF-74 by controlling the synthesis conditions
Gheorghe A., Imaz I., Van Der Vlugt J.I., Maspoch D., Tanase S. Dalton Transactions; 48 (27): 10043 - 10050. 2019. 10.1039/c9dt01572h. IF: 4.052

Supramolecular isomerism of metal-organic frameworks (MOFs) is known for several MOF structures, having direct implications on the properties of these materials. Although the synthesis of MOF isomers is mainly serendipitous in nature, achieving controlled formation of a target framework is highly relevant for practical applications. This work discusses the influence of additives and synthesis conditions on the formation of porous isomers containing Zn2+ as nodes and 2,5-dihydroxy-1,4-benzenedicarboxylate (dobdc4-) as a linker. Using solvent mixtures containing strongly coordinated molecules, e.g. N,N′-dimethylformamide (DMF) and N-methylpyrrolidone (NMP), facilitates the formation of porous structures of type [Zn2(dobdc)(S)x]·yS (S = DMF, NMP) which are built from dinuclear Zn2(O)2(CO2)3 secondary building units (SBUs) consisting of two different edge-sharing polyhedra with the Zn2+ ions in a unsaturated coordinative environment. In the presence of water, the Zn2+ dimers are converted to one-dimensional infinite Zn2+ chains, in which the number of Zn2+-linker bonds increases, therefore giving a hydrolytically more stable coordination environment. The full characterization of the isomers as well as their conversion to the most stable isomer is presented. © 2019 The Royal Society of Chemistry.

View abstract
Tuning the supramolecular isomerism of MOF-74 by controlling the synthesis conditions
Gheorghe A., Imaz I., Van Der Vlugt J.I., Maspoch D., Tanase S. Dalton Transactions; 48 (27): 10043 - 10050. 2019. 10.1039/c9dt01572h. IF: 4.052

Supramolecular isomerism of metal-organic frameworks (MOFs) is known for several MOF structures, having direct implications on the properties of these materials. Although the synthesis of MOF isomers is mainly serendipitous in nature, achieving controlled formation of a target framework is highly relevant for practical applications. This work discusses the influence of additives and synthesis conditions on the formation of porous isomers containing Zn2+ as nodes and 2,5-dihydroxy-1,4-benzenedicarboxylate (dobdc4-) as a linker. Using solvent mixtures containing strongly coordinated molecules, e.g. N,N′-dimethylformamide (DMF) and N-methylpyrrolidone (NMP), facilitates the formation of porous structures of type [Zn2(dobdc)(S)x]·yS (S = DMF, NMP) which are built from dinuclear Zn2(O)2(CO2)3 secondary building units (SBUs) consisting of two different edge-sharing polyhedra with the Zn2+ ions in a unsaturated coordinative environment. In the presence of water, the Zn2+ dimers are converted to one-dimensional infinite Zn2+ chains, in which the number of Zn2+-linker bonds increases, therefore giving a hydrolytically more stable coordination environment. The full characterization of the isomers as well as their conversion to the most stable isomer is presented. © 2019 The Royal Society of Chemistry.

View abstract

2018

A Self-Folding Polymer Film Based on Swelling Metal–Organic Frameworks
Troyano J., Carné-Sánchez A., Pérez-Carvajal J., León-Reina L., Imaz I., Cabeza A., Maspoch D. Angewandte Chemie - International Edition; 57 (47): 15420 - 15424. 2018. 10.1002/anie.201808433. IF: 12.102

Herein, we exploit the well-known swelling behaviour of metal–organic frameworks (MOFs) to create a self-folding polymer film. Namely, we show that incorporating crystals of the flexible MOF MIL-88A into a polyvinylidene difluoride (PVDF) matrix affords a polymer composite film that undergoes reversible shape transformations upon exposure to polar solvents and vapours. Since the self-folding properties of this film correlate directly with the swelling properties of the MIL-88A crystals, it selectively bends to certain solvents and its degree of folding can be controlled by controlling the relative humidity. Moreover, it shows a shape-memory effect at relative humidity values from 60 % to 90 %. As proof of concept, we demonstrate that these composite films can lift cargo and can be used to assemble 3D structures from 2D patterns. Our strategy is a straightforward method for designing autonomous soft materials with folding properties that can be tuned by judicious choice of the constituent flexible MOF. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
A Self-Folding Polymer Film Based on Swelling Metal–Organic Frameworks
Troyano J., Carné-Sánchez A., Pérez-Carvajal J., León-Reina L., Imaz I., Cabeza A., Maspoch D. Angewandte Chemie - International Edition; 57 (47): 15420 - 15424. 2018. 10.1002/anie.201808433. IF: 12.102

Herein, we exploit the well-known swelling behaviour of metal–organic frameworks (MOFs) to create a self-folding polymer film. Namely, we show that incorporating crystals of the flexible MOF MIL-88A into a polyvinylidene difluoride (PVDF) matrix affords a polymer composite film that undergoes reversible shape transformations upon exposure to polar solvents and vapours. Since the self-folding properties of this film correlate directly with the swelling properties of the MIL-88A crystals, it selectively bends to certain solvents and its degree of folding can be controlled by controlling the relative humidity. Moreover, it shows a shape-memory effect at relative humidity values from 60 % to 90 %. As proof of concept, we demonstrate that these composite films can lift cargo and can be used to assemble 3D structures from 2D patterns. Our strategy is a straightforward method for designing autonomous soft materials with folding properties that can be tuned by judicious choice of the constituent flexible MOF. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Aqueous production of spherical Zr-MOF beads: Via continuous-flow spray-drying
Avci-Camur C., Troyano J., Pérez-Carvajal J., Legrand A., Farrusseng D., Imaz I., Maspoch D. Green Chemistry; 20 (4): 873 - 878. 2018. 10.1039/c7gc03132g. IF: 8.586

Porous metal-organic frameworks (MOFs) are attracting great attention from industry, thanks to their myriad potential applications in areas such as catalysis and gas storage. Zr-MOFs (also known as UiO-type MOFs) are especially promising, owing to their large surface areas, high chemical versatility and remarkable hydrothermal, chemical and thermal stabilities. However, among the challenges currently precluding the industrial exploitation of MOFs is the lack of green methods for their synthesis. Herein we describe a continuous-flow spray-drying method for the simultaneous synthesis and shaping of spherical MOF microbeads in a mixture of water and acetic acid. We used this approach to build two archetypical Zr-MOFs: UiO-66-NH2 and Zr-fumarate. By tuning the concentration of acetic acid in water, we were able to produce, by a scalable process, UiO-66-NH2 and Zr-fumarate beads with SBET and water-sorption values comparable to the literature values obtained with other methods. © 2018 The Royal Society of Chemistry.

View abstract
Aqueous production of spherical Zr-MOF beads: Via continuous-flow spray-drying
Avci-Camur C., Troyano J., Pérez-Carvajal J., Legrand A., Farrusseng D., Imaz I., Maspoch D. Green Chemistry; 20 (4): 873 - 878. 2018. 10.1039/c7gc03132g. IF: 8.586

Porous metal-organic frameworks (MOFs) are attracting great attention from industry, thanks to their myriad potential applications in areas such as catalysis and gas storage. Zr-MOFs (also known as UiO-type MOFs) are especially promising, owing to their large surface areas, high chemical versatility and remarkable hydrothermal, chemical and thermal stabilities. However, among the challenges currently precluding the industrial exploitation of MOFs is the lack of green methods for their synthesis. Herein we describe a continuous-flow spray-drying method for the simultaneous synthesis and shaping of spherical MOF microbeads in a mixture of water and acetic acid. We used this approach to build two archetypical Zr-MOFs: UiO-66-NH2 and Zr-fumarate. By tuning the concentration of acetic acid in water, we were able to produce, by a scalable process, UiO-66-NH2 and Zr-fumarate beads with SBET and water-sorption values comparable to the literature values obtained with other methods. © 2018 The Royal Society of Chemistry.

View abstract
Boosting Self-Assembly Diversity in the Solid-State by Chiral/Non-Chiral ZnII-Porphyrin Crystallization
Qian W., González-Campo A., Pérez-Rodríguez A., Rodríguez-Hermida S., Imaz I., Wurst K., Maspoch D., Ruiz E., Ocal C., Barrena E., Amabilino D.B., Aliaga-Alcalde N. Chemistry - A European Journal; 24 (49): 12950 - 12960. 2018. 10.1002/chem.201802031. IF: 5.160

A chiral ZnII porphyrin derivative 1 and its achiral analogue 2 were studied in the solid state. Considering the rich molecular recognition of designed metalloporphyrins 1 and 2 and their tendency to crystallize, they were recrystallized from two solvent mixtures (CH2Cl2/CH3OH and CH2Cl2/hexane). As a result, four different crystalline arrangements (1 a,b and 2 a,b, from 0D to 2D) were obtained. Solid-state studies were performed on all the species to analyze the role played by chirality, solvent mixtures, and surfaces (mica and HOPG) in the supramolecular arrangements. By means of combinations of solvents and substrates a variety of microsized species was obtained, from vesicles to flower-shaped arrays, including geometrical microcrystals. Overall, the results emphasize the environmental susceptibility of metalloporphyrins and how this feature must be taken into account in their design. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Boosting Self-Assembly Diversity in the Solid-State by Chiral/Non-Chiral ZnII-Porphyrin Crystallization
Qian W., González-Campo A., Pérez-Rodríguez A., Rodríguez-Hermida S., Imaz I., Wurst K., Maspoch D., Ruiz E., Ocal C., Barrena E., Amabilino D.B., Aliaga-Alcalde N. Chemistry - A European Journal; 24 (49): 12950 - 12960. 2018. 10.1002/chem.201802031. IF: 5.160

A chiral ZnII porphyrin derivative 1 and its achiral analogue 2 were studied in the solid state. Considering the rich molecular recognition of designed metalloporphyrins 1 and 2 and their tendency to crystallize, they were recrystallized from two solvent mixtures (CH2Cl2/CH3OH and CH2Cl2/hexane). As a result, four different crystalline arrangements (1 a,b and 2 a,b, from 0D to 2D) were obtained. Solid-state studies were performed on all the species to analyze the role played by chirality, solvent mixtures, and surfaces (mica and HOPG) in the supramolecular arrangements. By means of combinations of solvents and substrates a variety of microsized species was obtained, from vesicles to flower-shaped arrays, including geometrical microcrystals. Overall, the results emphasize the environmental susceptibility of metalloporphyrins and how this feature must be taken into account in their design. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Metal Acetylacetonates as a Source of Metals for Aqueous Synthesis of Metal-Organic Frameworks
Avci-Camur C., Perez-Carvajal J., Imaz I., Maspoch D. ACS Sustainable Chemistry and Engineering; 6 (11): 14554 - 14560. 2018. 10.1021/acssuschemeng.8b03180. IF: 6.140

Demand continues for environmentally sound, high-yielding processes for the large-scale production of metal-organic frameworks (MOFs). Here we describe the use of metal acetylacetonate complexes as an alternative source of metals for the aqueous synthesis of MOFs. We have synthesized several carboxylate-based Zr(IV)-(UiO-66-NH2, Zr-fumarate, UiO-66-(OH)2, UiO-66-COOH and UiO-66-(COOH)2), Fe(III)-(MIL-88A) and Al(III)-(CAU-10) porous MOFs from their corresponding metal acetylacetonates in good yields (typically >85%) and, in some cases, at room temperature. © 2018 American Chemical Society.

View abstract
Metal Acetylacetonates as a Source of Metals for Aqueous Synthesis of Metal-Organic Frameworks
Avci-Camur C., Perez-Carvajal J., Imaz I., Maspoch D. ACS Sustainable Chemistry and Engineering; 6 (11): 14554 - 14560. 2018. 10.1021/acssuschemeng.8b03180. IF: 6.140

Demand continues for environmentally sound, high-yielding processes for the large-scale production of metal-organic frameworks (MOFs). Here we describe the use of metal acetylacetonate complexes as an alternative source of metals for the aqueous synthesis of MOFs. We have synthesized several carboxylate-based Zr(IV)-(UiO-66-NH2, Zr-fumarate, UiO-66-(OH)2, UiO-66-COOH and UiO-66-(COOH)2), Fe(III)-(MIL-88A) and Al(III)-(CAU-10) porous MOFs from their corresponding metal acetylacetonates in good yields (typically >85%) and, in some cases, at room temperature. © 2018 American Chemical Society.

View abstract
Photothermal Activation of Metal-Organic Frameworks Using a UV-Vis Light Source
Espín J., Garzón-Tovar L., Carné-Sánchez A., Imaz I., Maspoch D. ACS Applied Materials and Interfaces; 10 (11): 9555 - 9562. 2018. 10.1021/acsami.8b00557. IF: 8.097

Metal-organic frameworks (MOFs) usually require meticulous removal of the solvent molecules to unlock their potential porosity. Herein, we report a novel one-step method for activating MOFs based on the photothermal effect induced by directly irradiating them with a UV-vis lamp. The localized light-to-heat conversion produced in the MOF crystals upon irradiation enables a very fast solvent removal, thereby significantly reducing the activation time to as low as 30 min and suppressing the need for time-consuming solvent-exchange procedures and vacuum conditions. This approach is successful for a broad range of MOFs, including HKUST-1, UiO-66-NH2, ZIF-67, CPO-27-M (M = Zn, Ni, and Mg), Fe-MIL-101-NH2, and IRMOF-3, all of which exhibit absorption bands in the light emission range. In addition, we anticipate that this photothermal activation can also be used to activate covalent organic frameworks (COFs). © 2018 American Chemical Society.

View abstract
Photothermal Activation of Metal-Organic Frameworks Using a UV-Vis Light Source
Espín J., Garzón-Tovar L., Carné-Sánchez A., Imaz I., Maspoch D. ACS Applied Materials and Interfaces; 10 (11): 9555 - 9562. 2018. 10.1021/acsami.8b00557. IF: 8.097

Metal-organic frameworks (MOFs) usually require meticulous removal of the solvent molecules to unlock their potential porosity. Herein, we report a novel one-step method for activating MOFs based on the photothermal effect induced by directly irradiating them with a UV-vis lamp. The localized light-to-heat conversion produced in the MOF crystals upon irradiation enables a very fast solvent removal, thereby significantly reducing the activation time to as low as 30 min and suppressing the need for time-consuming solvent-exchange procedures and vacuum conditions. This approach is successful for a broad range of MOFs, including HKUST-1, UiO-66-NH2, ZIF-67, CPO-27-M (M = Zn, Ni, and Mg), Fe-MIL-101-NH2, and IRMOF-3, all of which exhibit absorption bands in the light emission range. In addition, we anticipate that this photothermal activation can also be used to activate covalent organic frameworks (COFs). © 2018 American Chemical Society.

View abstract
Postsynthetic Selective Ligand Cleavage by Solid-Gas Phase Ozonolysis Fuses Micropores into Mesopores in Metal-Organic Frameworks
Guillerm V., Xu H., Albalad J., Imaz I., Maspoch D. Journal of the American Chemical Society; 140 (44): 15022 - 15030. 2018. 10.1021/jacs.8b09682. IF: 14.357

Herein we report a novel, ozone-based method for postsynthetic generation of mesoporosity in metal-organic frameworks (MOFs). By carefully selecting mixed-ligand Zr-fcu-MOFs based on organic ligand pairs in which one ligand has ozone-cleavable olefin bonds and the other ligand is ozone-resistant, we were able to selectively break the cleavable ligand via ozonolysis to trigger fusion of micropores into mesopores within the MOF framework. This solid-gas phase method is performed at room-temperature, and, depending on the cleavable ligand used, the resultant ligand-fragments can be removed from the ozonated MOF by either washing or sublimation. Compared to the corresponding highly microporous starting MOFs, the highly mesoporous product MOFs exhibit radically distinct gas sorption properties. © 2018 American Chemical Society.

View abstract
Postsynthetic Selective Ligand Cleavage by Solid-Gas Phase Ozonolysis Fuses Micropores into Mesopores in Metal-Organic Frameworks
Guillerm V., Xu H., Albalad J., Imaz I., Maspoch D. Journal of the American Chemical Society; 140 (44): 15022 - 15030. 2018. 10.1021/jacs.8b09682. IF: 14.357

Herein we report a novel, ozone-based method for postsynthetic generation of mesoporosity in metal-organic frameworks (MOFs). By carefully selecting mixed-ligand Zr-fcu-MOFs based on organic ligand pairs in which one ligand has ozone-cleavable olefin bonds and the other ligand is ozone-resistant, we were able to selectively break the cleavable ligand via ozonolysis to trigger fusion of micropores into mesopores within the MOF framework. This solid-gas phase method is performed at room-temperature, and, depending on the cleavable ligand used, the resultant ligand-fragments can be removed from the ozonated MOF by either washing or sublimation. Compared to the corresponding highly microporous starting MOFs, the highly mesoporous product MOFs exhibit radically distinct gas sorption properties. © 2018 American Chemical Society.

View abstract
Purification of Uranium-based Endohedral Metallofullerenes (EMFs) by Selective Supramolecular Encapsulation and Release
Fuertes-Espinosa C., Gómez-Torres A., Morales-Martínez R., Rodríguez-Fortea A., García-Simón C., Gándara F., Imaz I., Juanhuix J., Maspoch D., Poblet J.M., Echegoyen L., Ribas X. Angewandte Chemie - International Edition; 57 (35): 11294 - 11299. 2018. 10.1002/anie.201806140. IF: 12.102

Supramolecular nanocapsule 1⋅(BArF)8 is able to sequentially and selectively entrap recently discovered U2@C80 and unprecedented Sc2CU@C80, simply by soaking crystals of 1⋅(BArF)8 in a toluene solution of arc-produced soot. These species, selectively and stepwise absorbed by 1⋅(BArF)8, are easily released, obtaining highly pure fractions of U2@C80 and Sc2CU@C80 in one step. Sc2CU@C80 represents the first example of a mixed metal actinide-based endohedral metallofullerene (EMF). Remarkably, the host–guest studies revealed that 1⋅(BArF)8 is able to discriminate EMFs with the same carbon cage but with different encapsulated cluster and computational studies provide support for these observations. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Purification of Uranium-based Endohedral Metallofullerenes (EMFs) by Selective Supramolecular Encapsulation and Release
Fuertes-Espinosa C., Gómez-Torres A., Morales-Martínez R., Rodríguez-Fortea A., García-Simón C., Gándara F., Imaz I., Juanhuix J., Maspoch D., Poblet J.M., Echegoyen L., Ribas X. Angewandte Chemie - International Edition; 57 (35): 11294 - 11299. 2018. 10.1002/anie.201806140. IF: 12.102

Supramolecular nanocapsule 1⋅(BArF)8 is able to sequentially and selectively entrap recently discovered U2@C80 and unprecedented Sc2CU@C80, simply by soaking crystals of 1⋅(BArF)8 in a toluene solution of arc-produced soot. These species, selectively and stepwise absorbed by 1⋅(BArF)8, are easily released, obtaining highly pure fractions of U2@C80 and Sc2CU@C80 in one step. Sc2CU@C80 represents the first example of a mixed metal actinide-based endohedral metallofullerene (EMF). Remarkably, the host–guest studies revealed that 1⋅(BArF)8 is able to discriminate EMFs with the same carbon cage but with different encapsulated cluster and computational studies provide support for these observations. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Self-assembly of polyhedral metal-organic framework particles into three-dimensional ordered superstructures
Avci C., Imaz I., Carné-Sánchez A., Pariente J.A., Tasios N., Pérez-Carvajal J., Alonso M.I., Blanco A., Dijkstra M., López C., Maspoch D. Nature Chemistry; 10 (1): 78 - 84. 2018. 10.1038/NCHEM.2875. IF: 26.201

Self-assembly of particles into long-range, three-dimensional, ordered superstructures is crucial for the design of a variety of materials, including plasmonic sensing materials, energy or gas storage systems, catalysts and photonic crystals. Here, we have combined experimental and simulation data to show that truncated rhombic dodecahedral particles of the metal-organic framework (MOF) ZIF-8 can self-assemble into millimetre-sized superstructures with an underlying three-dimensional rhombohedral lattice that behave as photonic crystals. Those superstructures feature a photonic bandgap that can be tuned by controlling the size of the ZIF-8 particles and is also responsive to the adsorption of guest substances in the micropores of the ZIF-8 particles. In addition, superstructures with different lattices can also be assembled by tuning the truncation of ZIF-8 particles, or by using octahedral UiO-66 MOF particles instead. These well-ordered, sub-micrometre-sized superstructures might ultimately facilitate the design of three-dimensional photonic materials for applications in sensing. © 2017 Macmillan Publishers Limited, part of Springer Nature.

View abstract
Self-assembly of polyhedral metal-organic framework particles into three-dimensional ordered superstructures
Avci C., Imaz I., Carné-Sánchez A., Pariente J.A., Tasios N., Pérez-Carvajal J., Alonso M.I., Blanco A., Dijkstra M., López C., Maspoch D. Nature Chemistry; 10 (1): 78 - 84. 2018. 10.1038/NCHEM.2875. IF: 26.201

Self-assembly of particles into long-range, three-dimensional, ordered superstructures is crucial for the design of a variety of materials, including plasmonic sensing materials, energy or gas storage systems, catalysts and photonic crystals. Here, we have combined experimental and simulation data to show that truncated rhombic dodecahedral particles of the metal-organic framework (MOF) ZIF-8 can self-assemble into millimetre-sized superstructures with an underlying three-dimensional rhombohedral lattice that behave as photonic crystals. Those superstructures feature a photonic bandgap that can be tuned by controlling the size of the ZIF-8 particles and is also responsive to the adsorption of guest substances in the micropores of the ZIF-8 particles. In addition, superstructures with different lattices can also be assembled by tuning the truncation of ZIF-8 particles, or by using octahedral UiO-66 MOF particles instead. These well-ordered, sub-micrometre-sized superstructures might ultimately facilitate the design of three-dimensional photonic materials for applications in sensing. © 2017 Macmillan Publishers Limited, part of Springer Nature.

View abstract
Sequential Deconstruction-Reconstruction of Metal-Organic Frameworks: An Alternative Strategy for Synthesizing (Multi)-Layered ZIF Composites
Avci C., Yazdi A., Tarrés M., Bernoud E., Bastús N.G., Puntes V., Imaz I., Ribas X., Maspoch D. ACS Applied Materials and Interfaces; 10 (28): 23952 - 23960. 2018. 10.1021/acsami.8b05098. IF: 8.097

Here, we report the synthesis of (multi)-layered zeolitic imidazolate framework (ZIF-8/-67) composite particles via a sequential deconstruction-reconstruction process. We show that this process can be applied to construct ZIF-8-on-ZIF-67 composite particles whose cores are the initially etched particles. In addition, we demonstrate that introduction of functional inorganic nanoparticles (INPs) onto the crystal surface of etched particles does not disrupt ZIF particle reconstruction, opening new avenues for designing (multi)-layered ZIF-on-INP-on-ZIF composite particles comprising more than one class of inorganic nanoparticles. In these latter composites, the location of the inorganic nanoparticles inside each single metal-organic framework particle as well as of their separation at the nanoscale (20 nm) is controlled. Preliminary results show that (multi)-layered ZIF-on-INP-on-ZIF composite particles comprising a good sequence of inorganic nanoparticles can potentially catalyze cascade reactions. Copyright © 2018 American Chemical Society.

View abstract
Sequential Deconstruction-Reconstruction of Metal-Organic Frameworks: An Alternative Strategy for Synthesizing (Multi)-Layered ZIF Composites
Avci C., Yazdi A., Tarrés M., Bernoud E., Bastús N.G., Puntes V., Imaz I., Ribas X., Maspoch D. ACS Applied Materials and Interfaces; 10 (28): 23952 - 23960. 2018. 10.1021/acsami.8b05098. IF: 8.097

Here, we report the synthesis of (multi)-layered zeolitic imidazolate framework (ZIF-8/-67) composite particles via a sequential deconstruction-reconstruction process. We show that this process can be applied to construct ZIF-8-on-ZIF-67 composite particles whose cores are the initially etched particles. In addition, we demonstrate that introduction of functional inorganic nanoparticles (INPs) onto the crystal surface of etched particles does not disrupt ZIF particle reconstruction, opening new avenues for designing (multi)-layered ZIF-on-INP-on-ZIF composite particles comprising more than one class of inorganic nanoparticles. In these latter composites, the location of the inorganic nanoparticles inside each single metal-organic framework particle as well as of their separation at the nanoscale (20 nm) is controlled. Preliminary results show that (multi)-layered ZIF-on-INP-on-ZIF composite particles comprising a good sequence of inorganic nanoparticles can potentially catalyze cascade reactions. Copyright © 2018 American Chemical Society.

View abstract
Single-Crystal-to-Single-Crystal Postsynthetic Modification of a Metal-Organic Framework via Ozonolysis
Albalad J., Xu H., Gándara F., Haouas M., Martineau-Corcos C., Mas-Ballesté R., Barnett S.A., Juanhuix J., Imaz I., Maspoch D. Journal of the American Chemical Society; 140 (6): 2028 - 2031. 2018. 10.1021/jacs.7b12913. IF: 14.357

We describe solid-gas phase, single-crystal-to-single-crystal, postsynthetic modifications of a metal-organic framework (MOF). Using ozone, we quantitatively transformed the olefin groups of a UiO-66-type MOF into 1,2,4-trioxolane rings, which we then selectively converted into either aldehydes or carboxylic acids. © 2018 American Chemical Society.

View abstract
Single-Crystal-to-Single-Crystal Postsynthetic Modification of a Metal-Organic Framework via Ozonolysis
Albalad J., Xu H., Gándara F., Haouas M., Martineau-Corcos C., Mas-Ballesté R., Barnett S.A., Juanhuix J., Imaz I., Maspoch D. Journal of the American Chemical Society; 140 (6): 2028 - 2031. 2018. 10.1021/jacs.7b12913. IF: 14.357

We describe solid-gas phase, single-crystal-to-single-crystal, postsynthetic modifications of a metal-organic framework (MOF). Using ozone, we quantitatively transformed the olefin groups of a UiO-66-type MOF into 1,2,4-trioxolane rings, which we then selectively converted into either aldehydes or carboxylic acids. © 2018 American Chemical Society.

View abstract
Squaramide-IRMOF-16 Analogue for Catalysis of Solvent-Free, Epoxide Ring-Opening Tandem and Multicomponent Reactions
Vignatti C., Luis-Barrera J., Guillerm V., Imaz I., Mas-Ballesté R., Alemán J., Maspoch D. ChemCatChem; 10 (18): 3995 - 3998. 2018. 10.1002/cctc.201801127. IF: 4.674

Tandem and multicomponent one-pot reactions are highly attractive because they enable synthesis of target molecules in a single reaction vessel. However, they are difficult to control, as they can lead to the formation of many undesired side-products. Herein we report the use of metal-organic framework (MOF) pores decorated with organocatalytic squaramide moieties to confine ring-opening epoxide reactions of diverse substrates. Controlled mono-addition or tandem reactions inside the pores yield 1,2-aminoalcohols or 1,2,2′-aminodialcohols, respectively, in good yields. In addition, this squaramide-functionalised MOF enables catalysis of higher-complexity multicomponent reactions such as the catalytic ring-opening of two different epoxides by a single amine to afford 1,2,2′-aminodialcohols. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Squaramide-IRMOF-16 Analogue for Catalysis of Solvent-Free, Epoxide Ring-Opening Tandem and Multicomponent Reactions
Vignatti C., Luis-Barrera J., Guillerm V., Imaz I., Mas-Ballesté R., Alemán J., Maspoch D. ChemCatChem; 10 (18): 3995 - 3998. 2018. 10.1002/cctc.201801127. IF: 4.674

Tandem and multicomponent one-pot reactions are highly attractive because they enable synthesis of target molecules in a single reaction vessel. However, they are difficult to control, as they can lead to the formation of many undesired side-products. Herein we report the use of metal-organic framework (MOF) pores decorated with organocatalytic squaramide moieties to confine ring-opening epoxide reactions of diverse substrates. Controlled mono-addition or tandem reactions inside the pores yield 1,2-aminoalcohols or 1,2,2′-aminodialcohols, respectively, in good yields. In addition, this squaramide-functionalised MOF enables catalysis of higher-complexity multicomponent reactions such as the catalytic ring-opening of two different epoxides by a single amine to afford 1,2,2′-aminodialcohols. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
The photothermal effect in MOFs: Covalent post-synthetic modification of MOFs mediated by UV-Vis light under solvent-free conditions
Espín J., Garzón-Tovar L., Boix G., Imaz I., Maspoch D. Chemical Communications; 54 (33): 4184 - 4187. 2018. 10.1039/c8cc01593g. IF: 6.290

Here, we report the covalent post-synthetic modification (CPSM) of MOFs using the photothermal effect. Specifically, we subjected mixtures of a photothermally active MOF and another reagent to irradiation with a UV-Vis lamp. This caused the MOF to heat up, which in turn caused the other reagent to melt and subsequently react with the functional groups on the walls of the MOF pores. We have exploited this dual function of MOFs as both heater and host for CPSMs to achieve rapid formation of amides from the reaction of representative MOFs (UiO-66-NH2 or MIL-101-NH2-(Al)) with anhydrides under solvent-free conditions. In addition, this approach enables more complex CPSMs in MOFs such as the formation of amides in UiO-66-NH2 by using an aldehyde through a cascade reaction. © 2018 The Royal Society of Chemistry.

View abstract
The photothermal effect in MOFs: Covalent post-synthetic modification of MOFs mediated by UV-Vis light under solvent-free conditions
Espín J., Garzón-Tovar L., Boix G., Imaz I., Maspoch D. Chemical Communications; 54 (33): 4184 - 4187. 2018. 10.1039/c8cc01593g. IF: 6.290

Here, we report the covalent post-synthetic modification (CPSM) of MOFs using the photothermal effect. Specifically, we subjected mixtures of a photothermally active MOF and another reagent to irradiation with a UV-Vis lamp. This caused the MOF to heat up, which in turn caused the other reagent to melt and subsequently react with the functional groups on the walls of the MOF pores. We have exploited this dual function of MOFs as both heater and host for CPSMs to achieve rapid formation of amides from the reaction of representative MOFs (UiO-66-NH2 or MIL-101-NH2-(Al)) with anhydrides under solvent-free conditions. In addition, this approach enables more complex CPSMs in MOFs such as the formation of amides in UiO-66-NH2 by using an aldehyde through a cascade reaction. © 2018 The Royal Society of Chemistry.

View abstract
Zigzag Ligands for Transversal Design in Reticular Chemistry: Unveiling New Structural Opportunities for Metal-Organic Frameworks
Guillerm V., Grancha T., Imaz I., Juanhuix J., Maspoch D. Journal of the American Chemical Society; 140 (32): 10153 - 10157. 2018. 10.1021/jacs.8b07050. IF: 14.357

Herein we describe the topological influence of zigzag ligands in the assembly of Zr(IV) metal-organic frameworks (MOFs). Through a transversal design strategy using reticular chemistry, we were able to synthesize a family of isoreticular Zr(IV)-based MOFs exhibiting the bcu - rather than the fcu - topology. Our findings underscore the value of the transversal parameter in organic ligands for dictating MOF architectures. © 2018 American Chemical Society.

View abstract
Zigzag Ligands for Transversal Design in Reticular Chemistry: Unveiling New Structural Opportunities for Metal-Organic Frameworks
Guillerm V., Grancha T., Imaz I., Juanhuix J., Maspoch D. Journal of the American Chemical Society; 140 (32): 10153 - 10157. 2018. 10.1021/jacs.8b07050. IF: 14.357

Herein we describe the topological influence of zigzag ligands in the assembly of Zr(IV) metal-organic frameworks (MOFs). Through a transversal design strategy using reticular chemistry, we were able to synthesize a family of isoreticular Zr(IV)-based MOFs exhibiting the bcu - rather than the fcu - topology. Our findings underscore the value of the transversal parameter in organic ligands for dictating MOF architectures. © 2018 American Chemical Society.

View abstract

2017

Composite Salt in Porous Metal-Organic Frameworks for Adsorption Heat Transformation
Garzón-Tovar L., Pérez-Carvajal J., Imaz I., Maspoch D. Advanced Functional Materials; 27 (21, 1606424) 2017. 10.1002/adfm.201606424. IF: 12.124

Adsorptive heat transformation systems such as adsorption thermal batteries and chillers can provide space heating and cooling in a more environmental friendly way. However, their use is still hindered by their relatively poor performances and large sizes due to the limited properties of solid adsorbents. Here, the spray-drying continuous-flow synthesis of a new type of solid adsorbents that results from combining metal-organic frameworks (MOFs), such as UiO-66, and hygroscopic salts, such as CaCl2 has been reported. These adsorbents, commonly named as composite salt in porous matrix (CSPM) materials, allow improving the water uptake capabilities of MOFs while preventing their dissolution in the water adsorbed; a common characteristic of these salts due to the deliquescence effect. It is anticipated that MOF-based CSPMs, in which the percentage of salt can be tuned, are promising candidates for thermal batteries and chillers. In these applications, it is showed that a CSPM made of UiO-66 and CaCl2 (38% w/w) exhibits a heat storage capacity of 367 kJ kg−1, whereas a second CSPM made of UiO-66 and CaCl2 (53% w/w) shows a specific cooling power of 631 W kg−1 and a coefficient of performance of 0.83, comparable to the best solid adsorbents reported so far. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Continuous One-Step Synthesis of Porous M-XF6-Based Metal-Organic and Hydrogen-Bonded Frameworks
Guillerm V., Garzón-Tovar L., Yazdi A., Imaz I., Juanhuix J., Maspoch D. Chemistry - A European Journal; 23 (28): 6829 - 6835. 2017. 10.1002/chem.201605507. IF: 5.317

Metal-organic frameworks (MOFs) built up from connecting M-XF6 pillars through N-donor ligands are among the most attractive adsorbents and separating agents for CO2 and hydrocarbons today. The continuous, one-step spray-drying synthesis of several members of this isoreticular MOF family varying the anionic pillar (XF6=[SiF6]2− and [TiF6]2−), the N-donor organic ligand (pyrazine and 4,4′-bipyridine) and the metal ion (M=Co, Cu and Zn) is demonstrated here. This synthetic method allows them to be obtained in the form of spherical superstructures assembled from nanosized crystals. As confirmed by CO2 and N2 sorption studies, most of the M-XF6-based MOFs synthesised through spray-drying can be considered “ready-to-use” sorbents as they do not need additional purification and time consuming solvent exchange steps to show comparable porosity and sorption properties with the bulk/single-crystal analogues. Stability tests of nanosized M-SiF6-based MOFs confirm their low stability in most solvents, including water and DMF, highlighting the importance of protecting them once synthesised. Finally, for the first time it was shown that the spray-drying method can also be used to assemble hydrogen-bonded open networks, as evidenced by the synthesis of MPM-1-TIFSIX. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Core-shell Au/CeO2 nanoparticles supported in UiO-66 beads exhibiting full CO conversion at 100 °c
Yazdi A., Abo Markeb A., Garzón-Tovar L., Patarroyo J., Moral-Vico J., Alonso A., Sánchez A., Bastus N., Imaz I., Font X., Puntes V., Maspoch D. Journal of Materials Chemistry A; 5 (27): 13966 - 13970. 2017. 10.1039/c7ta03006a. IF: 8.867

Hybrid core-shell Au/CeO2 nanoparticles (NPs) dispersed in UiO-66 shaped into microspherical beads are created using the spray-drying continuous-flow method. The combined catalytic properties of nanocrystalline CeO2 and Au in a single particle and the support and protective function of porous UiO-66 beads make the resulting composites show good performances as catalysts for CO oxidation (T50 = 72 °C; T100 = 100 °C) and recyclability. © 2017 The Royal Society of Chemistry.

View abstract
Leucine zipper motif inspiration: A two-dimensional leucine Velcro-like array in peptide coordination polymers generates hydrophobicity
Rodríguez-Hermida S., Evangelio E., Rubio-Martínez M., Imaz I., Verdaguer A., Juanhuix J., Maspoch D. Dalton Transactions; 46 (34): 11166 - 11170. 2017. 10.1039/c7dt02153d. IF: 4.029

Here, we show that the well-known hydrophobic leucine (Leu) zipper motif (also known as the coiled-coil or Leu scissors motif), typically found in proteins, can be used as a source of inspiration in coordination polymers built from Leu-containing dipeptides or tripeptides. We demonstrate that this motif can be extended to form Velcro-like layers of Leu, and that the hydrophobicity of these layers is transferred to coordination polymers, thereby enabling the development of a new type of hydrophobic materials. © 2017 The Royal Society of Chemistry.

View abstract
New synthetic routes towards MOF production at scale
Rubio-Martinez M., Avci-Camur C., Thornton A.W., Imaz I., Maspoch D., Hill M.R. Chemical Society Reviews; 46 (11): 3453 - 3480. 2017. 10.1039/c7cs00109f. IF: 38.618

The potential commercial applications for metal organic frameworks (MOFs) are tantalizing. To address the opportunity, many novel approaches for their synthesis have been developed recently. These strategies present a critical step towards harnessing the myriad of potential applications of MOFs by enabling larger scale production and hence real-world applications. This review provides an up-to-date survey (212 references) of the most promising novel synthetic routes, i.e., electrochemical, microwave, mechanochemical, spray drying and flow chemistry synthesis. Additionally, the essential topic of downstream processes, especially for large scale synthesis, is critically reviewed. Lastly we present the current state of MOF commercialization with direct feedback from commercial players. © The Royal Society of Chemistry 2017.

View abstract
Spray drying for making covalent chemistry II: Synthesis of covalent-organic framework superstructures and related composites
Garzón-Tovar L., Avci-Camur C., Rodríguez-San-Miguel D., Imaz I., Zamora F., Maspoch D. Chemical Communications; 53 (82): 11372 - 11375. 2017. 10.1039/c7cc07052g. IF: 6.319

Here we report a method that combines the spray-drying technique with a dynamic covalent chemistry process to synthesize zero-dimensional, spherical and microscale superstructures made from the assembly of imine-based COF nanocrystals. This methodology also enables the integration of other functional materials into these superstructures forming COF-based composites. © 2017 The Royal Society of Chemistry.

View abstract
Spray drying for making covalent chemistry: Postsynthetic modification of metal-organic frameworks
Garzón-Tovar L., Rodríguez-Hermida S., Imaz I., Maspoch D. Journal of the American Chemical Society; 139 (2): 897 - 903. 2017. 10.1021/jacs.6b11240. IF: 13.858

Covalent postsynthetic modification (PSM) of metal-organic frameworks (MOFs) has attracted much attention due to the possibility of tailoring the properties of these porous materials. Schiff-base condensation betwecn an amine and an aldehyde is one of the most common reactions in the PSM of MOFs. Here, we report the use of the spray drying technique to perform this class of organic reactions, either betwecn discrete organic molecules or on the pore surfaces of MOFs, in a very fast (1-2 s) and continuous way. Using spray drying, we show the PSM of two MOFs, the amine-terminated UiO-66-NH2 and the aldehyde-terminated ZIF-90, achieving conversion efficiencies up to 20 and 42%, respectively. Moreover, we demonstrate that it can also be used to postsynthetically cross-link the aldehyde groups of ZIF-90 using a diamine molecule with a conversion efficiency of 70%. © 2017 American Chemical Society.

View abstract
Systematic study of the impact of MOF densification into tablets on textural and mechanical properties
Dhainaut J., Avci-Camur C., Troyano J., Legrand A., Canivet J., Imaz I., Maspoch D., Reinsch H., Farrusseng D. CrystEngComm; 19 (29): 4211 - 4218. 2017. 10.1039/c7ce00338b. IF: 3.474

Four different metal-organic framework powders (UiO-66, UiO-66-NH2, UiO-67, and HKUST-1) were shaped into tablets. The effect of the applied pressure on porous properties, mechanical resistance and tablet bulk density is reported. We observe a linear relationship between densification and tensile strength for all four studied MOFs, with the slope being MOF-dependent. We also report conditions for improving significantly the volumetric uptake. Finally, we evaluated our tablets' stability over time in the presence of moisture. © 2017 The Royal Society of Chemistry.

View abstract
Tuning the Endocytosis Mechanism of Zr-Based Metal-Organic Frameworks through Linker Functionalization
Orellana-Tavra C., Haddad S., Marshall R.J., Abánades Lázaro I., Boix G., Imaz I., Maspoch D., Forgan R.S., Fairen-Jimenez D. ACS Applied Materials and Interfaces; 9 (41): 35516 - 35525. 2017. 10.1021/acsami.7b07342. IF: 7.504

A critical bottleneck for the use of metal-organic frameworks (MOFs) as drug delivery systems has been allowing them to reach their intracellular targets without being degraded in the acidic environment of the lysosomes. Cells take up particles by endocytosis through multiple biochemical pathways, and the fate of these particles depends on these routes of entry. Here, we show the effect of functional group incorporation into a series of Zr-based MOFs on their endocytosis mechanisms, allowing us to design an efficient drug delivery system. In particular, naphthalene-2,6-dicarboxylic acid and 4,4′-biphenyldicarboxylic acid ligands promote entry through the caveolin-pathway, allowing the particles to avoid lysosomal degradation and be delivered into the cytosol and enhancing their therapeutic activity when loaded with drugs. © 2017 American Chemical Society.

View abstract

2016

A First Cyclodextrin-Transition Metal Coordination Polymer
Xu H., Rodríguez-Hermida S., Pérez-Carvajal J., Juanhuix J., Imaz I., Maspoch D. Crystal Growth and Design; 16 (10): 5598 - 5602. 2016. 10.1021/acs.cgd.6b01115. IF: 4.425

The synthesis, X-ray crystallographic structure, and water uptake measurements of the first coordination polymer made of a cyclodextrin and a transition metal ion (in this case, Cu2+) are shown. This coordination polymer is made by connecting paddle-wheel Cu2+ units through a γ-cyclodextrin functionalized with eight carboxylate groups, is stable in water, and shows selective water-induced reversible structural transformations. © 2016 American Chemical Society.

View abstract
Application of metal and metal oxide nanoparticles at MOFs
Falcaro P., Ricco R., Yazdi A., Imaz I., Furukawa S., Maspoch D., Ameloot R., Evans J.D., Doonan C.J. Coordination Chemistry Reviews; 307: 237 - 254. 2016. 10.1016/j.ccr.2015.08.002. IF: 12.994

Composites based on Metal-Organic Frameworks (MOFs) are an emerging class of porous materials that have been shown to possess unique functional properties. Nanoparticles at MOFs composites combine the tailorable porosity of MOFs with the versatile functionality of metal or metaloxide nanoparticles. A wide range of nanoparticles at MOFs have been synthesised and their performance characteristics assessed in molecular adsorption and separation, catalysis, sensing, optics, sequestration of pollutants, drug delivery, and renewable energy. This review covers the main research areas where nanoparticles at MOFs have been strategically applied and highlights the scientific challenges to be considered for their continuing development. © 2015 Published by Elsevier B.V.

View abstract
Enhanced Spin Tunneling in a Molecular Magnet Mixed with a Superconductor
Tejada J., Zarzuela R., García-Santiago A., Imaz I., Espin J., Maspoch D., Chudnovsky E.M. Journal of Superconductivity and Novel Magnetism; 29 (5): 1133 - 1137. 2016. 10.1007/s10948-016-3474-6. IF: 1.100

We report characterization and magnetic studies of mixtures of micrometer-size ribbons of Mn12 acetate and micrometer-size particles of YBaCuO superconductor. Extremely narrow zero-field spin-tunneling resonance has been observed in the mixtures, pointing to the absence of the inhomogeneous dipolar broadening. It is attributed to the screening of the internal magnetic fields in the magnetic particles by Meissner currents flowing between superconducting grains surrounding the particles. © 2016, Springer Science+Business Media New York.

View abstract
Freezing the Nonclassical Crystal Growth of a Coordination Polymer Using Controlled Dynamic Gradients
Rubio-Martinez M., Imaz I., Domingo N., Abrishamkar A., Mayor T.S., Rossi R.M., Carbonell C., deMello A.J., Amabilino D.B., Maspoch D., Puigmartí-Luis J. Advanced Materials; : 8150 - 8155. 2016. 10.1002/adma.201506462. IF: 18.960

An experiment was conducted to show that diffusion-limited and kinetically controlled growth regimes occurring in microfluidic devices can provide valuable insights into crystallization processes. The microfluidic channels employed in this study were structured in PDMS master form fabricated by standard photolithographic techniques. Before attaching the cured and structured PDMS mould to a glass coverslip through plasma activation, inlet holes connecting the microfluidic channels were punched with a Biopsy puncher. The cross-sectional dimensions of the microchannels were 50 μm into 50 μm for the four input microchannels, and 250 μm into 50 μm for the main reactor channel. The total length of the main reactor channel was 9 mm. Data were indexed, integrated, and scaled using HKL2000 software. The H atoms were included in theoretical positions but not refined. The low max value was due to the data collection process, which was performed in the BM16 line with only a phi scan. The structure was solved by direct methods using the program SHELXS-97. The AFM results suggest that the early stage isolated seeds organize at a single level and in a perpendicular fashion, leading to the final plate-like crystalline morphologies observed in bulk and at an FFR of 0.1.

View abstract
Hetero-bimetallic paddlewheel clusters in coordination polymers formed by a water-induced single-crystal-to-single-crystal transformation
Albalad J., Aríñez-Soriano J., Vidal-Gancedo J., Lloveras V., Juanhuix J., Imaz I., Aliaga-Alcalde N., Maspoch D. Chemical Communications; 52 (91): 13397 - 13400. 2016. 10.1039/c6cc07653j. IF: 6.567

Herein we report a water-induced single-crystal to single-crystal transformation that involves the formation of hetero-bimetallic paddlewheel clusters in coordination polymers. Through this transformation, which involves the cleavage and formation of different coordination bonds, two different Cu(ii)-Zn(ii) and Cu(ii)-Ni(ii) paddlewheel units exhibiting a 1:1 metal ratio were created. © 2016 The Royal Society of Chemistry.

View abstract
Influence of the Amide Groups in the CO2/N2 Selectivity of a Series of Isoreticular, Interpenetrated Metal-Organic Frameworks
Safarifard V., Rodríguez-Hermida S., Guillerm V., Imaz I., Bigdeli M., Tehrani A.A., Juanhuix J., Morsali A., Casco M.E., Silvestre-Albero J., Ramos-Fernandez E.V., Maspoch D. Crystal Growth and Design; 16 (10): 6016 - 6023. 2016. 10.1021/acs.cgd.6b01054. IF: 4.425

Here we report the use of a pillaring strategy for the design and synthesis of three novel amide-functionalized metal-organic frameworks (MOFs), TMUs-22/-23/-24, isoreticular to the recently reported imine-functionalized TMU-6 and TMU-21 MOFs. An extensive study of their CO2 sorption properties and selectivity for CO2 over N2, from single gas sorption isotherms to breakthrough measurements, revealed that not only the incorporation of amide groups but also their accessibility is crucial to obtain enhanced CO2 sorption and CO2/N2 selectivity. Therefore, the MOF with more accessible amide groups (TMU-24) shows a CO2/N2 selectivity value of ca. 10 (as revealed by breakthrough experiments), which is ca. 500% and 700% of the selectivity values observed for the other amide-containing (TMU-22 and TMU-23) and imine-containing (TMU-6 and TMU-21) MOFs. © 2016 American Chemical Society.

View abstract
Introducing asymmetric functionality into MOFs: Via the generation of metallic Janus MOF particles
Ayala A., Carbonell C., Imaz I., Maspoch D. Chemical Communications; 52 (29): 5096 - 5099. 2016. 10.1039/c6cc01098a. IF: 6.567

Herein we report a versatile methodology for engineering metallic Janus MOF particles based on desymmetrization at interfaces, whereby each MOF particle is partially coated with a desired metal. We demonstrate that it enables the fabrication of homogeneous Janus MOF particles according to the MOF (ZIF-8, UiO-66 or UiO-66-SH), the metal (Au, Co or Pt), the MOF particle size (from the micrometer to the submicrometer regime) and the metal-film thickness (from 5 nm to 50 nm) employed. We anticipate that our strategy could be applied to impart new functionalities to MOFs, including asymmetric functionalization, magnetic-guidance and motorization. © The Royal Society of Chemistry 2016.

View abstract
Narrowing the Zero-Field Tunneling Resonance by Decreasing the Crystal Symmetry of Mn12 Acetate
Espín J., Zarzuela R., Statuto N., Juanhuix J., Maspoch D., Imaz I., Chudnovsky E., Tejada J. Journal of the American Chemical Society; 138 (29): 9065 - 9068. 2016. 10.1021/jacs.6b05380. IF: 13.038

We report the discovery of a less symmetric crystalline phase of Mn12 acetate, a triclinic phase, resulting from recrystallizing the original tetragonal phase reported by Lis in acetonitrile and toluene. This new phase exhibits the same structure of Mn12 acetate clusters and the same positions of tunneling resonances on the magnetic field as the conventional tetragonal phase. However, the width of the zero-field resonance is at least 1 order of magnitude smaller - can be as low as 50 Oe - indicating very small inhomogeneous broadening due to dipolar and nuclear fields. © 2016 American Chemical Society.

View abstract
pH-Responsive Relaxometric Behaviour of Coordination Polymer Nanoparticles Made of a Stable Macrocyclic Gadolinium Chelate
Aríñez-Soriano J., Albalad J., Carné-Sánchez A., Bonnet C.S., Busqué F., Lorenzo J., Juanhuix J., Terban M.W., Imaz I., Tóth É., Maspoch D. Chemistry - A European Journal; 22 (37): 13162 - 13170. 2016. 10.1002/chem.201602356. IF: 5.771

Lanthanide-containing nanoscale particles have been widely explored for various biomedical purposes, however, they are often prone to metal leaching. Here we have created a new coordination polymer (CP) by applying, for the first time, a stable GdIIIchelate as building block in order to prevent any fortuitous release of free lanthanide(III) ion. The use of the Gd-DOTA-4AmP complex as a design element in the CP allows not only for enhanced relaxometric properties (maximum r1=16.4 mm−1s−1at 10 MHz), but also for a pH responsiveness (Δr1=108 % between pH 4 and 6.5), beyond the values obtained for the low molecular weight Gd-DOTA-4AmP itself. The CP can be miniaturised to the nanoscale to form colloids that are stable in physiological saline solution and in cell culture media and does not show cytotoxicity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Single-crystal and humidity-controlled powder diffraction study of the breathing effect in a metal-organic framework upon water adsorption/desorption
Aríñez-Soriano J., Albalad J., Vila-Parrondo C., Pérez-Carvajal J., Rodríguez-Hermida S., Cabeza A., Juanhuix J., Imaz I., Maspoch D. Chemical Communications; 52 (45): 7229 - 7232. 2016. 10.1039/c6cc02908f. IF: 6.567

Herein we report a study on water adsorption/desorption-triggered single-crystal to single-crystal transformations in a MOF, by single-crystal and humidity-controlled powder X-ray diffraction and water-sorption measurements. We identified a gate-opening effect at a relative humidity of 85% upon water adsorption, and a gate-closure effect at a relative humidity of 55 to 77% upon water desorption. This reversible breathing effect between the "open" and the "closed" structures of the MOF involves the cleavage and formation of several coordination bonds. © 2016 The Royal Society of Chemistry.

View abstract
Switchable Surface Hydrophobicity–Hydrophilicity of a Metal–Organic Framework
Rodríguez-Hermida S., Tsang M.Y., Vignatti C., Stylianou K.C., Guillerm V., Pérez-Carvajal J., Teixidor F., Viñas C., Choquesillo-Lazarte D., Verdugo-Escamilla C., Peral I., Juanhuix J., Verdaguer A., Imaz I., Maspoch D., Giner Planas J. Angewandte Chemie - International Edition; 55 (52): 16049 - 16053. 2016. 10.1002/anie.201609295. IF: 11.709

Materials with surfaces that can be switched from high/superhydrophobicity to superhydrophilicity are useful for myriad applications. Herein, we report a metal–organic framework (MOF) assembled from ZnIIions, 1,4-benzenedicarboxylate, and a hydrophobic carborane-based linker. The MOF crystal-surface can be switched between hydrophobic and superhydrophilic through a chemical treatment to remove some of the building blocks. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

View abstract
Two-step synthesis of heterometallic coordination polymers using a polyazamacrocyclic linker
Aríñez-Soriano J., Albalad J., Pérez-Carvajal J., Imaz I., Busqué F., Juanhuix J., Maspoch D. CrystEngComm; 18 (22): 4196 - 4204. 2016. 10.1039/c5ce02520f. IF: 3.849

A new macrocyclic linker 1,4,7,10-tetraazacyclododecane-1,7-bis(4-acetamidobenzoic)-4,10-diacetic acid (H4L1) was synthesized and characterized. This linker was used to create two heterometallic coordination polymers following a two-step synthesis. This synthesis consisted of first combining this polyazamacrocyclic linker with Ni(ii) or Mn(ii) ions to obtain the corresponding metallomacrocyclic complexes showing non-coordinated carboxylic groups. In a second step, these metallated macrocycles were used as building units to construct two heterometallic Ni(ii)-Zn(ii) and Mn(ii)-Zn(ii) coordination polymers when combined with Zn(ii) ions. In addition, a third Zn(ii)-Zn(ii) coordination polymer could also be synthesized by direct mixing of H4L1 with Zn(ii) ions. Interestingly, the Mn(ii)-Zn(ii) coordination polymer exhibits a reversible type-I "crystal-to-amorphous transformation" upon water sorption/desorption. © The Royal Society of Chemistry.

View abstract

2015

Engineering Homochiral Metal-Organic Frameworks by Spatially Separating 1D Chiral Metal-Peptide Ladders: Tuning the Pore Size for Enantioselective Adsorption
Stylianou K.C., Gõmez L., Imaz I., Verdugo-Escamilla C., Ribas X., Maspoch D. Chemistry - A European Journal; 21 (28): 9964 - 9969. 2015. 10.1002/chem.201501315. IF: 5.731

The reaction of the chiral dipeptide glycyl-L(S)-glutamate with CoII ions produces chiral ladders that can be used as rigid 1D building units. Spatial separation of these building units with linkers of different lengths allows the engineering of homochiral porous MOFs with enhanced pore sizes, pore volumes, and surface areas. This strategy enables the synthesis of a family of isoreticular MOFs, in which the pore size dictates the enantioselective adsorption of chiral molecules (in terms of their size and enantiomeric excess). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

View abstract
Lanthanide-organic framework nanothermometers prepared by spray-drying
Wang Z., Ananias D., Carné-Sánchez A., Brites C.D.S., Imaz I., Maspoch D., Rocha J., Carlos L.D. Advanced Functional Materials; 25 (19): 2824 - 2830. 2015. 10.1002/adfm.201500518. IF: 11.805

Accurate, noninvasive, and self-referenced temperature measurements at the submicrometer scale are of great interest, prompted by the ever-growing demands in the fields of nanotechnology and nanomedicine. The thermal dependence of the phosphor's luminescence provides high detection sensitivity and spatial resolution with short acquisition times in, e.g., biological fluids, strong electromagnetic fields, and fast-moving objects. Here, it is shown that nanoparticles of [(Tb0.914Eu0.086)2(PDA)3(H2O)]·2H2O (PDA = 1,4-phenylenediacetic acid), the first lanthanide-organic framework prepared by the spray-drying method, are excellent nanothermometers operating in the solid state in the 10-325 K range (quantum yield of 0.25 at 370 nm, at room temperature). Intriguingly, this system is the most sensitive cryogenic nanothermometer reported so far, combining high sensitivity (up to 5.96 ± 0.04% K-1 at 25 K), reproducibility (in excess of 99%), and low-temperature uncertainty (0.02 K at 25 K). One of the most sensitive cryogenic thermometers (5.96% K-1 at 25 K) reported so far is described, consisting of lanthanide (Tb3+, Eu3+) organic framework nanoparticles prepared by spray-drying, exhibiting an excellent reproducibility (>99%) and low-temperature uncertainty (0.02 K at 25 K). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

View abstract
Optimised room temperature, water-based synthesis of CPO-27-M metal-organic frameworks with high space-time yields
Garzón-Tovar L., Carné-Sánchez A., Carbonell C., Imaz I., Maspoch D. Journal of Materials Chemistry A; 3 (41): 20819 - 20826. 2015. 10.1039/c5ta04923g. IF: 7.443

The exceptional porosity of Metal-Organic Frameworks (MOFs) could be harnessed for countless practical applications. However, one of the challenges currently precluding the industrial exploitation of these materials is a lack of green methods for their synthesis. Since green synthetic methods obviate the use of organic solvents, they are expected to reduce the production costs, safety hazards and environmental impact typically associated with MOF fabrication. Herein we describe the stepwise optimisation of reaction parameters (pH, reagent concentrations and reaction time) for the room temperature, water-based synthesis of several members of the CPO-27/MOF-74-M series of MOFs, including ones made from Mg(ii), Ni(ii), Co(ii) and Zn(ii) ions. Using this method, we built MOFs with excellent BET surface areas and unprecedented Space-Time Yields (STYs). Employing this approach, we have synthesised CPO-27-M MOFs with record BET surface areas, including 1279 m2 g-1 (CPO-27-Zn), 1351 m2 g-1 (CPO-27-Ni), 1572 m2 g-1 (CPO-27-Co), and 1603 m2 g-1 (CPO-27-Mg). We anticipate that our method could be applied to produce CPO-27-Ni, -Mg, -Co and -Zn with STYs of 44 kg m-3 per day, 191 kg m-3 per day, 1462 kg m-3 per day and a record 18720 kg m-3 per day, respectively. © The Royal Society of Chemistry.

View abstract
Post-Synthetic Anisotropic Wet-Chemical Etching of Colloidal Sodalite ZIF Crystals
Avci C., Ariñez-Soriano J., Carné-Sánchez A., Guillerm V., Carbonell C., Imaz I., Maspoch D. Angewandte Chemie - International Edition; 54 (48): 14417 - 14421. 2015. 10.1002/anie.201507588. IF: 11.261

Controlling the shape of metal-organic framework (MOF) crystals is important for understanding their crystallization and useful for myriad applications. However, despite the many advances in shaping of inorganic nanoparticles, post-synthetic shape control of MOFs and, in general, molecular crystals remains embryonic. Herein, we report using a simple wet-chemistry process at room temperature to control the anisotropic etching of colloidal ZIF-8 and ZIF-67 crystals. Our work enables uniform reshaping of these porous materials into unprecedented morphologies, including cubic and tetrahedral crystals, and even hollow boxes, by an acid-base reaction and subsequent sequestration of leached metal ions. Etching tests on these ZIFs reveal that etching occurs preferentially in the crystallographic directions richer in metal-ligand bonds; that, along these directions, the etching rate tends to be faster on the crystal surfaces of higher dimensionality; and that the etching can be modulated by adjusting the pH of the etchant solution. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

View abstract
Protecting metal-organic framework crystals from hydrolytic degradation by spray-dry encapsulating them into polystyrene microspheres
Carné-Sánchez A., Stylianou K.C., Carbonell C., Naderi M., Imaz I., Maspoch D. Advanced Materials; 27 (5): 869 - 873. 2015. 10.1002/adma.201403827. IF: 17.493

A one-step, alternative, rapid, and scalable spray-drying (SD) synthesis of metal-organic frameworks (MOF)@polymer composites with enhanced hydrolytic stabilities was reported. SD was used to encapsulate preformed MOF crystals in a polymeric matrix to generate microscale MOF@polymer spheres. For proof-of-concept Hong-Kong University of Science and Technology-1 (HKUST-1) was chosen as the water-sensitive MOF, and polystyrene (PS) as the organic polymer. The synthesis of HKUST-1@PS began with preparation of a stable colloidal suspension of HKUST-1 crystals and a solution of PS in dichloromethane (DCM). This mixture was atomized using a two-fluid nozzle. After 40 min of continuous spraying, 1.7 g of a blue powder was recovered. The sample was then washed with ethanol and dried at 120°C under vacuum. This product was analyzed through field-emission scanning electron microscopy (FESEM), which indicated that it comprised smooth microspheres of HKUST-1@PS composites and did not contain any free HKUST-1. X-ray powder diffraction (XRPD) analysis of these spheres revealed a perfect match with the HKUST-1 pattern. The exclusive presence of microspheres and the match in XRPD patterns evidenced that HKUST-1 crystals were indeed entrapped within the polymeric matrix of PS.

View abstract
Resonant spin tunneling in randomly oriented nanospheres of Mn12 acetate
Lendínez S., Zarzuela R., Tejada J., Terban M.W., Billinge S.J.L., Espin J., Imaz I., Maspoch D., Chudnovsky E.M. Physical Review B - Condensed Matter and Materials Physics; 91 (2, 024404) 2015. 10.1103/PhysRevB.91.024404. IF: 3.736

We report measurements and theoretical analysis of resonant spin tunneling in randomly oriented nanospheres of a molecular magnet. Amorphous nanospheres of Mn12 acetate have been fabricated and characterized by chemical, infrared, TEM, x-ray, and magnetic methods. Magnetic measurements have revealed sharp tunneling peaks in the field derivative of the magnetization that occur at the typical resonant field values for the Mn12 acetate crystal in the field parallel to the easy axis. Theoretical analysis is provided that explains these observations. We argue that resonant spin tunneling in a molecular magnet can be established in a powder sample, without the need for a single crystal and without aligning the easy magnetization axes of the molecules. This is confirmed by reanalyzing the old data on a powdered sample of nonoriented micron-size crystals of Mn12 acetate. Our findings can greatly simplify the selection of candidates for quantum spin tunneling among newly synthesized molecular magnets. © 2015 American Physical Society.

View abstract
Synthesis, culture medium stability, and in vitro and in vivo zebrafish embryo toxicity of metal-organic framework nanoparticles
Ruyra A., Yazdi A., Espín J., Carné-Sánchez A., Roher N., Lorenzo J., Imaz I., Maspoch D. Chemistry - A European Journal; 21 (6): 2508 - 2518. 2015. 10.1002/chem.201405380. IF: 5.731

Metal-organic frameworks (MOFs) are among the most attractive porous materials available today. They have garnered much attention for their potential utility in many different areas such as gas storage, separation, catalysis, and biomedicine. However, very little is known about the possible health or environmental risks of these materials. Here, the results of toxicity studies on sixteen representative uncoated MOF nanoparticles (nanoMOFs), which were assessed for cytotoxicity to HepG2 and MCF7 cells in vitro, and for toxicity to zebrafish embryos in vivo, are reported. Interestingly, there is a strong correlation between their in vitro toxicity and their in vivo toxicity. NanoMOFs were ranked according to their respective in vivo toxicity (in terms of the amount and severity of phenotypic changes observed in the treated zebrafish embryos), which varied widely. Altogether these results show different levels of toxicity of these materials; however, leaching of solubilized metal ions plays a main role. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

View abstract
Two New Adenine-Based Co(II) Coordination Polymers: Synthesis, Crystal Structure, Coordination Modes, and Reversible Hydrochromic Behavior
Burneo I., Stylianou K.C., Rodríguez-Hermida S., Juanhuix J., Fontrodona X., Imaz I., Maspoch D. Crystal Growth and Design; 15 (7): 3182 - 3189. 2015. 10.1021/acs.cgd.5b00218. IF: 4.891

We report the synthesis of two new three-dimensional coordination polymers (CPs) based on Co(II), adenine, and aromatic tetracarboxylate linkers. Adenine exhibits bidentate binding modes in both CPs, coordinating through the N3 and N9 sites in a first compact CP and through the more rare N3 and N7 sites in a second open, flexible, and H2O-responsive CP. These differences together with an analysis of the extended coordination structures made of adenine reported in the Cambridge Structural Database illustrate the rich coordination versatility of adenine as a building block for CPs. Although the latter CP is nonporous to N2 or CO2, it shows a reversible and detectable color change from pink to purple, and vice versa, upon hydration and dehydration, respectively. (Graph Presented). © 2015 American Chemical Society.

View abstract

2014

Localized, stepwise template growth of functional nanowires from an amino acid-supported framework in a microfluidic chip
Puigmartí-Luis, J.; Rubio-Martínez, M.; Imaz, I.; Cvetkovic, B.Z.; Abad, L.; Pérez Del Pino, A.; Maspoch, D.; Amabilino, D.B. ACS Nano; 8 (1): 818 - 826. 2014. 10.1021/nn4054864. IF: 12.033
Metal-organic frameworks: From molecules/metal ions to crystals to superstructures
Carné-Sánchez, A.; Imaz, I.; Stylianou, K.C.; Maspoch, D. Chemistry - A European Journal; 20 (18): 5192 - 5201. 2014. 10.1002/chem.201304529. IF: 5.696
Sponge-like molecular cage for purification of fullerenes
García-Simón, C.; Garcia-Borràs, M.; Gómez, L.; Parella, T.; Osuna, S.; Juanhuix, J.; Imaz, I.; Maspoch, D.; Costas, M.; Ribas, X. Nature Communications; 2014. 10.1038/ncomms6557. IF: 10.742
The influence of the enantiomeric ratio of an organic ligand on the structure and chirality of metal-organic frameworks
Burneo, I.; Stylianou, K.C.; Imaz, I.; Maspoch, D. Chemical Communications; 50 (89): 13829 - 13832. 2014. 10.1039/c4cc06190j. IF: 6.718

2013

A spray-drying strategy for synthesis of nanoscale metal-organic frameworks and their assembly into hollow superstructures
Carné-Sánchez, A.; Imaz, I.; Cano-Sarabia, M.; Maspoch, D. Nature Chemistry; 5: 203 - 211. 2013. 10.1038/nchem.1569. IF: 21.757
Dual-Template synthesis of one-dimensional conductive nanoparticle superstructures from coordination metal-peptide polymer crystals
Rubio-Martínez, M.; Puigmartí-Luis, J.; Imaz, I.; Dittrich, P.S.; Maspoch, D. Small; 9 (24): 4160 - 4167. 2013. 10.1002/smll.201301338. IF: 7.823
Extended H-bond networks based on guanidinium H-donors and [Zr(A) 4]4- H-acceptor units: Modulation of the assemblage and guest accessible volume by chemical design (A = oxalate, dihydrobenzoquinonate, chloranilate)
Mouchaham, G.; Roques, N.; Duhayon, C.; Imaz, I.; Sutter, J.-P. New Journal of Chemistry; 37: 3476 - 3487. 2013. 10.1039/c3nj00520h. IF: 2.966
Femtolitre chemistry assisted by microfluidic pen lithography
Carbonell, C. ; Stylianou, K. C. ; Hernando, J.; Evangelio, E. ; Barnett, S. A.; Nettikadan, S. ; Imaz, I.; Maspoch, D. Nature Communications; 4: 2173. 2013. 10.1038/ncomms3173. IF: 10.015
Relaxometry studies of a highly stable nanoscale metal-organic framework made of Cu(II), Gd(III), and the macrocyclic DOTP
Carné-Sánchez, A.; Bonnet, C.S.; Imaz, I.; Lorenzo, J.; Tóth, E.; Maspoch, D. Journal of the American Chemical Society; 135 (47): 17711 - 17714. 2013. 10.1021/ja4094378. IF: 10.677
Self-assembled tetragonal prismatic molecular cage highly selective for anionic Ï€ guests
GarcÃa-SimÃ³n, C.; Garcia-BorrÃ s, M.; GÃ³mez, L.; Garcia-Bosch, I.; Osuna, S.; Swart, M.; Luis, J.M.; Rovira, C.; Almeida, M.; Imaz, I.; Maspoch, D.; Costas, M.; Ribas, X. Chemistry - A European Journal; 19: 1445 - 1456. 2013. 10.1002/chem.201203376. IF: 5.831
Tetradihydrobenzoquinonate and tetrachloranilate Zr(IV) complexes: Single-crystal-to-single-crystal phase transition and open-framework behavior for K4Zr(DBQ)4
Imaz, I.; Mouchaham, G.; Roques, N.; Brandès, S.; Sutter, J.-P. Inorganic Chemistry; 52: 11237 - 11243. 2013. 10.1021/ic401474f. IF: 4.593

2012

Three-dimensional porous metal-radical frameworks based on triphenylmethyl radicals
Datcu, A.; Roques, N.; Jubera, V.; Maspoch, D.; Fontrodona, X.; Wurst, K.; Imaz, I.; Mouchaham, G.; Sutter, J.-P.; Rovira, C.; Veciana, J. Chemistry - A European Journal; 18: 152 - 162. 2012. 10.1002/chem.201102278.

2011

Controlling the length and location of in situ formed nanowires by means of microfluidic tools
Kuhn, P.; Puigmartí-Luis, J.; Imaz, I.; Maspoch, D.; Dittrich, P.S. Lab on a Chip - Miniaturisation for Chemistry and Biology; 11: 753 - 757. 2011. 10.1039/c0lc00270d.
Coordination polymer nanofibers generated by microfluidic synthesis
Puigmartí-Luis, J.; Rubio-Martínez, M.; Hartfelder, U.; Imaz, I.; Maspoch, D.; Dittrich, P.S. Journal of the American Chemical Society; 133: 4216 - 4219. 2011. 10.1021/ja110834j.
Metal-biomolecule frameworks (MBioFs)
Imaz, I.; Rubio-Martínez, M.; An, J.; Solé-Font, I.; Rosi, N.L.; Maspoch, D. Chemical Communications; 47: 7287 - 7302. 2011. 10.1039/c1cc11202c.
Nanoscale metal-organic materials
Carné, A.; Carbonell, C.; Imaz, I.; Maspoch, D. Chemical Society Reviews; 40: 291 - 305. 2011. 10.1039/c0cs00042f.
Single-crystal metal-organic framework arrays
Carbonell, C.; Imaz, I.; Maspoch, D. Journal of the American Chemical Society; 133: 2144 - 2147. 2011. 10.1021/ja2002428.
Three-dimensional open-frameworks based on LnIII ions and open-/closed-Shell PTM ligands: Synthesis, structure, luminescence, and magnetic properties
Datcu, A.; Roques, N.; Jubera, V.; Imaz, I.; Maspoch, D.; Sutter, J.-P.; Rovira, C.; Veciana, J. Chemistry - A European Journal; 17: 3644 - 3656. 2011. 10.1002/chem.201002993.

2010

Coordination polymer particles as potential drug delivery systems
Imaz, I.; Rubio-Martínez, M.; García-Fernández, L.; García, F.; Ruiz-Molina, D.; Hernando, J.; Puntes, V.; Maspoch, D. Chemical Communications; 46: 4737 - 4739. 2010. 10.1039/c003084h.
Effect of crystalline disorder on quantum tunneling in the single-molecule magnet Mn12 benzoate
Carbonera, C.; Luis, F.; Campo, J.; Sánchez-Marcos, J.; Camón, A.; Chaboy, J.; Ruiz-Molina, D.; Imaz, I.; Van Slageren, J.; Dengler, S.; González, M. Physical Review B - Condensed Matter and Materials Physics; 81: 014427-1 - 014427-10. 2010. 10.1103/PhysRevB.81.014427.
Formation of metal-bioorganic nanofibres on a microchip
Hartfelder, U.; Puigmartí-Luis, J.; Imaz, I.; Maspoch, D.; Dittrich, P.S. European Cells and Materials; 20: 103. 2010. .
Towards nanowire sensors on a microfluidic platform: In-situ formation, positioning and sizing of nanowire bundles
Kuhn, P.; Puigmartí-Luis, J.; Imaz, I.; Maspoch, D.; Dittrich, P.S. European Cells and Materials; 20: 58. 2010. .

2009

Amino acid based metal-organic nanofibers
Imaz, I.; Rubio-Martínez, M.; Saletra, W.J.; Amabilino, D.B.; Maspoch, D. Journal of the American Chemical Society; 131: 18222 - 18223. 2009. 10.1021/ja908721t.
Metal-organic spheres as functional systems for guest encapsulation
Imaz, I.; Hernando, J.; Ruiz-Molina, D.; Maspoch, D. Angewandte Chemie - International Edition; 48: 2325 - 2329. 2009. .

2008

Catechol derivatives as fluorescent chemosensors for wide-range pH detection
Evangelio, E.; Hernando, J.; Imaz, I.; Bardají, G.G.; Alibés, R.; Busqué, F.; Ruiz-Molina, D. Chemistry - A European Journal; 14: 9754 - 9763. 2008. 10.1002/chem.200800722.
Magnetic behaviour of Mn12 single-molecule magnet nanospheres
Carbonera, C.; Imaz, I.; Maspoch, D.; Ruiz-Molina, D.; Luis, F. Inorganica Chimica Acta; 361: 3951 - 3956. 2008. 10.1016/j.ica.2008.03.037.
Nanosized trigonal prismatic and antiprismatic CuII coordination cages based on tricarboxylate linker
Anna Company; Nans Roques; Mireia Güell; Veronica Mugnaini; Laura Gómez; Inhar Imaz; Angela Datcu; Miquel Solà; Josep M. Luis; Jaume Veciana; Xavi Ribas and Miquel Costas Dalton Transactions; 1: 1679 - 1682. 2008. 10.1039/B800027C .
Octanuclear {Co6W2} aggregate versus mixed valence {Co}3 cluster in the assembling of Co(phen)2Cl2 (phen = 1,10-phenanthroline) with octacyano metallates: a case of non-isotructurality between {W(CN)8}4- and {Nb(CN)8}4-
Thengarai S. Venkatakrishnan; Inhar Imaz; Jean-Pascal Sutter Inorganica Chimica Acta; 361: 3710 - 3713. 2008. 10.1016/j.ica.2008.03.104.
Single-molecule magnet behaviour in metal-organic nanospheres generated by simple precipitation of Mn12O12 clusters
Imaz, I.; Luis, F.; Carbonera, C.; Ruiz-Molina, D.; Maspoch, D. Chemical Communications; : 1202 - 1204. 2008. 10.1039/b716071b.
Synthesis and structure of iron (III) and iron (II) complexes in S(4)P(2) environment created by Diethyldithiocarbamate and 1,2-bis(diphenylphosphino)ethane chelation: Investigation of the electronic structure of the complexes by Mossbauer and magnetic
Tanmay K. Jana; Dhurjati P. Kumar; Rabindranath Pradhan; Subhajit Dindaa; Pradip N. Ghosh; Corine Simonnet; Jérome Marrot; Inhar Imaz; Alain Wattiaux; Léopold Fournès; Jean-Pascal Sutter; Francis Sécheresse; Ramgopal Bhattacharyya Inorganica Chimica Acta; 362: 3583 - 3594. 2008. 10.1016/j.ica.2009.04.007.
Valence-tautomeric metal-organic nanoparticles
Imaz, I.; Maspoch, D.; Rodríguez-Blanco, C.; Pérez-Falcón, J.M.; Campo, J.; Ruiz-Molina, D. Angewandte Chemie - International Edition; 47: 1857 - 1860. 2008. 10.1002/anie.200705263.

2007

New insights into the thermal stability of Mn12 clusters: The case of complex [Mn12O12(O2CCCH) 16(H2O)4]·3H2O and its thermolysis derived [Mn3(O2CCCH)6(H 2O)4]·2H2O complex
Gómez-Segura, J.; Campo, J.; Imaz, I.; Wurst, K.; Veciana, J.; Gerbier, P.; Ruiz-Molina, D. Dalton Transactions; : 2450 - 2456. 2007. 10.1039/b700298j.
New insights into the thermal stability of Mn12 clusters: The case of complex [Mn12O12(O2CC[triple bond, length as m-dash]CH)16(H2O)4]·3H2O and its thermolysis derived [Mn3(O2CC[triple bond, length as m-dash]CH)6(H2O)4]·2H2O complex
Jordi Gómez-Segura; Javier Campo; Inhar Imaz; Klaus Wurst; Jaume Veciana; Philippe Gerbiere; Daniel Ruiz-Molina Dalton Transactions; 2007. .
New insights into the thermal stability of Mn12clusters: The case of complex [Mn12O12(O2CCºCH)16 (H2O)4 ]*3H2O and its thermolysis derived [Mn3(O2CCºCH)6(H2O)4]*2H2O complex
Gómez-Segura J.; J. Campo; I. Imaz; K. Wurst; J. Veciana; P. Gerbier; D. Ruiz-Molina Journal of the Chemical Society - Dalton Transactions; 31: 2450 - 2456. 2007. .

2006

A new hexaferrocene complex with a [M3(Î¿3-O)] 7+ core
Mereacre, V.; Nakano, M.; Gómez-Segura, J.; Imaz, I.; Sporer, C.; Wurst, K.; Veciana, J.; Turta, C.; Ruiz-Molina, D.; Jaitner, P. Inorganic Chemistry; 45: 10443 - 10445. 2006. 10.1021/ic061322s.