Hydrothermal synthesis, crystal structures and photoluminescent properties of four cadmium(II) coordination polymers derived from diphenic acid and auxiliary ligands

Abstract

Four novel metal coordination polymers, [Cd(dpa)(H 2O)] n ( 1), [Cd(dpa)(2,2′-bipy)] n ( 2), {[Cd 2(dpa) 2(4,4′-bipy) 3](4,4′-bipy)(H 2O) 2} n ( 3) and [Cd(dpa)(bim) 2(H 2O)]} n ( 4) (H 2dpa = 2,4′-biphenyl-dicarboxylic acid, 2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine, bim = benzimidazole), have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Single-crystal X-ray analyses reveal that the 2,4′-diphenic acids acts as bridging ligands, exhibiting rich coordination modes to link metal ions: bis-monodentate, bidentate chelating, chelating/bridging, monoatomic bridging and monodentate modes. In addition, the luminescent properties for compound 1– 4 are also investigated in this work.