Complexes of cobalt(II), nickel(II) and copper(II) with ortho- and para-phenylenediamine derivatives

Cobalt(II), nickel(II) and copper(II) complexes with BOP-H-2 (dibenzoinlidene-o-phenylenediamine) and BPP-H-2 (dibenzoinlidene-p-phenylenediamine) of general formulae [M(H2L)X-2], [M-2(H2L)(2)X-4], [M(L)] and [M-2(L)(2)] (where M = Co, Ni, Cu; X = Cl or NO3; H2L and L are the neutral and dibasic forms of the ligands) have been prepared by the reaction of the corresponding metal salts with the two ligands in neutral and basic media. The complexes were characterised by elemental analysis, electrical conductance, magnetic susceptibility and spectral measurements. The studies revealed two different actions of the ligands, neutral tetradentate in neutral medium giving hexacoordinated metal atoms with octahedral geometry and dibasic tetradentate in alkaline solution giving tetrahedral and square planar structures. (C) 1998 Elsevier Science Ltd. All rights reserved.