The influence of ligand configuration, solvent size and solvent polarity on the porous shape and void volume in a series of isomeric or isomorphic porous MOFs

Abstract

This article systematically reports various solvent systems and synthetic methods to induce isomerism and isomorphism in eight isomeric complexes. The “T” shape and “Y” shape configurations of the ligand lead to 1D “rectangle” shaped and “parallelogram” shaped channels in 3D frameworks. A solvent with a larger molar volume or lower solvent polarity is beneficial to construct porous MOFs with larger porous sizes and higher solvent void volumes. Solvent void volumes of 3D MOFs 6-3 > 6-2 > 6-1 > 1 > 4 > 3 corresponding to the coordinated solvent sizes DMP > DMA > DMF > MeOH > H₂O and the coordinated solvent polarities DMP < DMA < DMF (polar aprotic solvents), < MeOH < H₂O (polar protic solvents). It is notable that a suitable temperature and synthesis reactor are also crucial in the synthesis of porous MOFs. The related properties of complexes 1–6 are studied. The complexes which possess higher solvent void volumes are not thermally stable. Magnetic susceptibility measurements indicate that compounds 1–6 exhibit anti-ferromagnetic coupling between adjacent Mn(II) ions.