SYNTHESIS AND CHARACTERIZATION OF COBALT(II) AND COBALT(III) COMPLEXES OF SUBSTITUTED DIBENZOTETRAAZA[14]ANNULENES

The macrocyclic complexes Co(II)L1.2H2O and Co(II)L2 (L1H2 = Bz2Bzo2Me4 [14]hexaeneN4, L2H2 = Bz2Bzo2Me2Ph2[14]hexaeneN4) have been synthesized from free ligands and cobalt(II) acetate tetrahydrate. They reacted with dioxygen in pyridine solution to give the corresponding [Co(III)L(py)2]X complex (where X = BF4-, I-). The new compounds were characterized by elemental analysis, magnetic moments, IR, H-1 NMR and MS data. The steric non-equivalence of the axial sites of the coordinated macrocyclic ligands is discussed on the basis of the H-1 NMR spectra of the cobalt(III) complexes. The new cobalt complexes were found to be efficient catalysts for auto-oxidation of benzenethiol to diphenyl disulphide.