Synthesis And Characterization Of Bisbenzimidazol Ligands And Their Complexes

The benzimidazole compounds, as one kind of nitrogen-containing heterocyclic compounds, have π-π stacking structure and a plurality of lone pair of electrons, as well as good biological activity. The aromatic polycarboxylic acids and their derivatives are easy to form coordination compounds with various transition metal ions and lanthanoid metal ions, and these complexes often have excellent structures and properties. In this paper, we have designed and synthesized seven transition metal compound complexes with aromatic polycarboxylic acids and bisbenzimidazole ligands by use of hydrothermal synthesis method. These complexes have been characterized structurally by means of elemental analysis, infrared spectroscopy and single-crystal X-ray diffraction analysis.1. Using the hydrothermal synthesis method, five transition metal complexes, [Mn(HO-BDC)(bbop)]n (M1),{[Co2(HO-BDC)(bbop-)2]·2H2O}n (M2), [Ni(HO-BDC)(bbop)]n (M3),{[Ni2(HO-BDC) (bbop-)2]·2H2O}n (M4) and [Cd2(HO-BDC)(bbop-)2]n (M5), have been synthesized by the reaction of 1,3-bis(2-benzimidazolyl)-2-oxa-propane (bbop) and 5-hydroxy isophthalic acid (HO-H2BDC) with the transition metal salts MnCl2·4H2O, CoCl2·6H2O, NiCl2·6H2O and CdCl2·2.5H2O, respectively. Complex M1 crystallized orthorhombic P212121space group. Complexes M2, M4 and M5 crystallized monoclinic C2/c space group. Complex M3 crystallized orthorhombic.Pbca space group. The central ion Mn(II) of M1 is six-coordinated and forms a distorted octahedral geometry. Compound M1 forms a three-dimensional supramolecular structure. The central ions of M2 and M5 are four-coordinated and form tetrahedral coordination environment. Compounds M2 and M5 are two-dimensional network structures. The central ion of M3 is six-coordinated octahedral geometry. Compound M3 forms a two-dimensional network structure. The central ion of M4 is five-coordinated and forms a pyramid geometry. Compound M4 forms a two-dimensional network topology.2. Two transition metal complexes, [Cd(HOABDC)(bbop)]n (M6) and [Sn2(OABDC)2(H2bbop)]n (M7), have been synthesized by the hydrothermal method by the reaction of 1,3-bis(2-benzimidazolyl)-2-oxa-propane (bbop) and 5-oxyacetate isophthalic acid (H3OABDC) with the transition metal salts CdCl2-2.5H2O and SnCl2·2H2O, respectively. Complex M6 crystallized triclinic P1 pace group and M7 crystallized monoclinic P21/n space group. The central ion Cd(Ⅱ) of M6 is six-coordinated and forms an octahedral geometry. Compound M6 is a one-dimensional chain structure. The central ion Sn(Ⅱ) of M7 is three-coordinated. Compound M6 forms a two-dimensional network structure.