Cobalt(II) and nickel(II) complexes with 1-methyl-2-pyridin-2-yl-1H- and 1-methyl-2-phenyliminomethyl-1H-benzimidazoles and the closo-decaborate anion

Synthesis of cobalt(II) and nickel(II) complexes with the closo-decaborate anion and benzimidazole derivatives (L1 = C13N3H11, L2 = C15N3H13) of the general formula [ML3][B10H10] (M = Co, Ni) is described. Complexes have been characterized by elemental analysis, IR and UV spectroscopy. The structure of a [Ni(L1)3][B10H10] · 1.797CH3CN single crystal has been determined by X-ray diffraction. The imidazole and pyridine N atoms of three L1 molecules, two of which are disordered, form the distorted octahedral environment of the Ni atom. In the crystal, the majority of complexes [Ni(L1)3]2+ have the meridional configuration. The Ni-N bonds with the imidazole nitrogen atoms (2.010(4)–2.076(3) Å) are shorter than those with the pyridine atoms (2.132(4)–2.179(5) Å). This nonequivalence of the Ni-N bonds is responsible for the low magnetic susceptibility of the compound.