A metal-organic framework based on Co(II) and 3-aminoisonicotinate showing specific and reversible colourimetric response to solvent exchange with variable magnet behaviour Pajuelo Corral, Oier Rodríguez Diéguez, Antonio Cepeda, Javier CO2 adsorption Solvent-triggered reversible Transformations Colorimetric sensing Single-molecule magnet behaviour MOFs Supplementary data to this article can be found online at https://doi.org/10.1016/j.mtchem.2022.100794. This work has been funded by the Spanish Ministry of Science, Innovation and Universities (MCIU/AEI/FEDER, UE; PGC2018- 102052-A-C22, PGC2018-102052-B-C21 and PID2019-108028GBC21), University of the Basque Country (GIU20/028), Gobierno Vasco/Eusko Jaurlaritza (IT1005-16, IT1291-19) and Junta de Andalucía (FQM-394, B-FQM-734-UGR20). O.P.C. thanks his predoctoral fellowship to UPV/EHU. The authors thank for technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF). A versatile metal-organic system consisting of Co-based compounds that show reversible transformations between a 3D metal-organic framework (MOF) of {[Co(μ-3isoani)2]·DMF}n (1) formula (where 3isoani = 3-aminoisonicotinato and DMF = dimethylformamide) and a 0D monomeric [Co(3isoani)2(H2O)4] (2) complex is reported. These 1 ↔ 2 transformations, triggered by the exposure of the MOF and the monomer-based compound to H2O and DMF, respectively, involve colour changes from purple (in MOF 1) to light brown (in monomeric complex 2), which imbues the system with colourimetric sensing capacity towards these solvents. Despite the high reactivity of the MOF in contact with water, it presents good thermal stability and permanent porosity with a remarkably high CO2 capture capacity at room temperature (3.35 mmol/g), which is further analysed by in situ single-crystal X-ray diffraction. Experimental magnetic properties and CASSCF/NEVPT2 calculations of all compounds reveal distinct slow magnetic relaxations for 3D and 0D compounds. 2022-03-28T10:54:00Z 2022-03-28T10:54:00Z 2022 journal article O. Pajuelo-Corral, S. Pérez-Yáñez, I.J. Vitorica-Yrezabal et al. A metal-organic framework based on Co(II) and 3-aminoisonicotinate showing specific and reversible colourimetric response to solvent exchange with variable magnet behaviour. Materials Today Chemistry 24 (2022) 100794 [https://doi.org/10.1016/j.mtchem.2022.100794] http://hdl.handle.net/10481/73835 10.1016/j.mtchem.2022.100794 eng http://creativecommons.org/licenses/by-nc-nd/3.0/es/ open access Atribución-NoComercial-SinDerivadas 3.0 España Elsevier