Construction of 0D, 1D and 2D cobalt(II) complexes containing flexible bis(benzimidazole) and dicarboxylic acid ligands

Abstract

Three complexes {[Co0.5(HL1)(H2O)2]·(tbta)} n (1), [Co0.5(L2)(ndc)0.5] n (2) and [Co(L3)(tp)] n (3) (L1 = 1,3-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H2tbta = tetrabromoterephthalic acid, L2 = 1,4-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H2ndc = 2,6-naphthalenedicarboxylic acid, L3 = 1,3-bis(2-methylbenzimidazol-1-ylmethyl)benzene, H2tp = 1,4-benzenedicarboxylic acid) based on flexible bis(benzimidazole) derivatives have been synthesized under hydrothermal conditions and characterized by physicochemical and spectroscopic methods as well as single-crystal X-ray diffraction analysis. The analysis reveals that complex 1 features a mononuclear structure, which is further assembled into a 2D supermolecular framework via O–H···O hydrogen bond interactions. Complex 2 shows a 1D zigzag chain connected by ndc2− ligands, while 3 exhibits a 2D 4-connected layer and ultimately is extended into a 3D supramolecular network through two kinds of π···π stacking interactions. Moreover, the fluorescence and catalytic properties of the complexes for the degradation of the Congo red azo dye in a Fenton-like process are discussed.