Syntheses, structures, and properties of two 2-D Cd(II) complexes based on 2-(1H-imidazol-1-methyl)-1H-benzimidazole and polycarboxylate ligands

Abstract

Two 2-D Cd(II) complexes, {[Cd(imb)(bdc)(H2O)]·CH3OH}n (1) and {[Cd(imb)(Hbtc)(CH3OH)]·2H2O·CH3OH}n (2), have been synthesized by reactions of CdCl2·2.5H2O with 2-(1H-imidazol-1-methyl)-1H-benzimidazole (imb) and 1,3-benzenedicarboxylic acid (H2bdc) or 1,3,5-benzenetricarboxylic acid (H3btc). Single-crystal X-ray diffraction shows that 1 possesses an infinite 2-D layered structure in which all the carboxylates chelate Cd(II) and imb bridge Cd(II) ions. Complex 2 also features an infinite 2-D layered structure and imb ligands also bridge Cd(II) ions, but two carboxylates of each 1,3,5-benzenetricarboxylate coordinate to Cd(II) in monodentate or chelating mode, leaving the third one, which is not deprotonated, uncoordinated. IR spectra, fluorescent properties, and thermogravimetric analyses of both complexes have been investigated.