Metal–organic frameworks with pyridyl- and carboxylate-containing ligands: syntheses, structures and properties

Abstract

Assembly reactions of pyridyl- and carboxylate-containing ligand 5-(isonicotinamido)isophthalic acid (H₂INAIP) with corresponding metal salts result in formation of six new coordination polymers, namely {[Mn(INAIP)(DMF)]·0.5DMF}_n (1), {[Mn(INAIP)(H₂O)₂]·4H₂O}_n (2), {[Co(INAIP)(H₂O)]·2H₂O}_n (3), {[Co(INAIP)(bpy)_0.5]}_n (4), {[Co(INAIP)(Him)(H₂O)]·H₂O}_n (5), and {[Cu(INAIP)(Him)(H₂O)]·H₂O}_n (6) (DMF = N,N-dimethylformamide, bpy = 4,4′-bipyridine, Him = imidazole). The results of single-crystal X-ray diffraction analysis indicate that 1 is a two-fold interpenetrated three-dimensional (3D) framework with sra topology, complexes 2, 5 and 6 have two-dimensional (2D) network structure with (6,3) topology, while 3 and 4 have infinite 2D bi-layer structure with different topologies. Complex 3 exhibits a 4-connected network with the Schläfli symbol (4³·6³), and 4 displays a (4,5)-connected net with Schläfli symbol (4³·5²·6)(4³·5⁵·6²). The magnetic and adsorption properties of the complexes were investigated.