Complexes of 2-aminobenzimidazole with cobalt(II) and nickel(II)

Abstract

2-Aminobenzimidazole (abi) has been used to prepare (i) pseudotetrahedral complexes with cobalt or nickel of the types M(abi)₂X₂(M = Co, X = Cl, Br, I, NCS, and MeCOO; M = Ni, X = Br), [Et₄N][M(abi)X₃](M = Co, X = Cl, Br, and I; M = Ni, X = Br), Co(abi)₂I₂,2Me₂CO, Co(abi)SO₄,Me₂CO, Ni(abi)₂Cl₂,2H₂O, Ni(abi)₂I₂,3H₂O, and Co(abi – H)₂;(ii) square-planar complexes of nickel of the type Ni(abi)₄X₂(X = Cl, Br, I, NO₃, ClO₄, and ½SO₄); and (iii) distorted octahedral complexes Ni(abi)Br₂,H₂O, Ni(abi)₄(NCS)₂, Ni(abi)₃(NCS)₂, and Ni(abi)₂-(MeCOO)₂. The complex Ni(abi)₄(BF₄)₂ appears to have metal atoms in both square-planar and tetrahedral environments. These conclusions are based on electronic and i.r. spectral data and on magnetic moments of the complexes.