Co(II), Ni(II) and Cu(II) complexes of some new azocoumarin derivatives

The 3d transition metal ion [Co(II), Ni(II) and Cu(II)] complexes of some new azocoumarin derivatives have been isolated and characterized by elemental analysis, conductance, electronic and IR spectra. These dyes express a high tendency towards complex formation with the monovalent anion of L-1-L-4 and the neutral molecules of L-5 coordinated to the metal ion as bidentate ligands. The molecular formula of the 1 : 1 complexes is suggested to be [MLCl(H2O)(3)]X or [MLCl2(H2O)(2)], respectively. The different bands observed in the visible spectra of ethanolic solutions of the complexes have been assigned to the possible electronic transition type (L --> MCT and d-d). It is suggested that the complexes studied have a distorted octahedral geometry.