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

Four novel metal coordination polymers, [Cd(dpa)(H(2)O)](n) (1), [Cd(dpa)(2,2'-bipy)](n) (2), {[Cd(2)(dpa)(2)(4,4'-bipy) 3](4,4'-bipy)(H(2)O)(2)}(n) (3) and [Cd(dpa)(bim)(2)(H(2)O)]}(n) (4) (H(2)dpa = 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. (c) 2010 Elsevier B. V. All rights reserved.