Syntheses, Structures and Photoluminescence of Three Cd(II) Coordination Polymers Based on Flexible Bis(Benzimidazole) and Dicarboxylate Ligands

Three new Cd(II) coordination polymers constructed from two structurally related ligands, 1,1'-(1,3-propane) bis-(2-methylbenzimidazole) (pbmb) and 1,1'(1,4-butanediyl)bis(2-methyl-benzimidazole) (bbmi), have been hydrothermally synthesized: [Cd(pbmb)(hmph)](n) (1), [Cd(pbmb)(chdc)](n) (2) and [Cd(bbmi)(0.5)(chdc)](n) (3), where H2hmph = homophthalic acid and H(2)chdc = 1,4-cyclohexanedicarboxylic acid. These complexes were structurally characterized by elemental analysis, IR, and single crystal X-ray diffraction analyses. Complex 1 possesses a two-dimensional 6(3) honeycombed network structure, which are further extended into a 3D supermolecule framework through weak C-H center dot center dot center dot O hydrogen bonding interactions. 2 displays an infinite 1D loop-like chain structure, which is further assembled into a 2D supramolecular layer via C-H center dot center dot center dot O hydrogen bonding interactions. In complex 3, Cd-II ions are connected by chdc(2-) anions to form a 1D chain containing binuclear clusters, which is further connected by the bbmi exhibiting a 2D (3,4)-connected network with a point symbol of {4(2).6(3).8}{4(2).6}. The thermal and photoluminescence properties of the three complexes were investigated in detail. Graphical Abstract Three Cd(II) coordination polymers constructed by flexible bis-(2-methylbenzimidazole) and dicarboxylate anions co-ligands. These compounds display diverse architectures from 1D to 2D. The various structures indicate that flexible dicarboxylate anions have a remarkable effect on the final structures and topologies. [GRAPHICS] .