Cobalt(II), nickel(II), and copper(II) complexes of 2-methylimidazole

The preparation and spectral and magnetic properties are reported for complexes of cobalt(II), nickel(II), and copper(II) with 2-methylimidazole (Mlz). The complexes (Mlz)2CoX2(X = Cl, Br, or I), (Mlz)2NiX2(X = Br or I), and (Mlz)2CuX2(X = Cl or Br) have tetrahedral structures whereas (Mlz)2NiCl2 has a polymeric octahedral structure. The structures of the 'inner' complexes (Mlz′)2N (Mlz′= C4H5N2; N = Ni, Co, or Cu) together with that of (Mlz)4CuCl2 are described. The complexes are compared with those of 2-methylpyridine and the differences discussed in terms of steric hindrance and basicity.