Syntheses, Structures, and Physical Properties of Three Novel Metal−Organic Frameworks Constructed from Aromatic Polycarboxylate Acids and Flexible Imidazole-Based Synthons

Three novel interesting coordination polymers, [Cd 3 (SIP) 2 (bbi) 5 ·3H 2 O] n ( 1 ), [Co 3 (SIP) 2 (bix) 4 (2H 2 O)·2H 2 O] n ( 2 ), and [Cd(2,5-pydc) 2 (bix) 1.5 ·H 2 O] n ( 3 ) (SIP = 5-sulfoisophthalic acid monosodium salt; bbi = 1,1‘-(1,4-butanediyl)bis(imidazole); bix = 1,4-bis(imidazol-1-ylmethyl)-benzene; 2,5-pydc = pyridine-2,5-dicarboxylic acid), have been isolated under hydrothermal conditions and structurally characterized. Polymer 1 has a 3D complicated framework comprised of an infinite 1D ladder-like chain and 2D layer structure. Polymer 2 features a 3D hydrated framework with uncoordinated water molecules trapped in the pores. Polymer 3 is a 2D infinite layer framework, which is further interconnected by hydrogen-bond interactions to lead to a 3D supramolecular architecture. Compounds 1 and 3 exhibit medium-strong fluorescent emissions in the solid state at room temperature and could be significant in the field of photoactive materials.