Synthesis and spectral properties of the complexes of cobalt(II), nickel(II), copper(II), zinc(II), and cadmium(II) with 2-(thiomethyl-2′- benzimidazolyl)-benzimidazole

Abstract Synthesis of 2‐(thiomethyl‐2′‐benzimidazolyl)benzimidazole (L) and its metal complexes of the formulae ML2(ClO4)2 · xH2O (M = Co, x = 3; M = Ni, Zn, or Cd, x = 2; M = Cu, x = 1) and MLBr2 (M = Co, Ni, Cu, Zn, or Cd) are described. They have been characterized by measuring physical properties, IR, NMR, and electronic spectral studies. The electronic spectral and magnetic moment data suggest an octahedral geometry for the cobalt(II) and nickel(II) perchlorate complexes, a tetrahedral geometry for the cobalt(II) and nickel(II) bromo complexes and a pseudo tetrahedral geometry for the copper(II) perchlorate and copper(II) bromide complexes. Based on elemental analyses, conductivity measurements and IR and NMR spectral studies, a six‐coordinate geometry for cadmium perchlorate complex and various four‐coordinate geometries for zinc perchlorate and bromo complexes of cadmium and zinc have been proposed.