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, [Cd3(SIP)2(bbi)5·3H2O]n (1), [Co3(SIP)2(bix)4(2H2O)·2H2O]n (2), and
[Cd(2,5-pydc)2(bix)1.5·H2O]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.