MONONUCLEAR AND BINUCLEAR DIOXOMOLYBDENUM(VI) COMPLEXES WITH POLYDENTATE SCHIFF-BASE LIGANDS

Molybdenum, the only metal among the heavier transition elements which has a major role as a trace element in enzymes, forms several mono- and binuclear complexes, which may be termed as classical or Wernerian and also has a rich chemistry of metal-metal bonded compounds, called non-classical or non-Wernerian complexes. In this paper several mono-nuclear complexes of MoO22+ are reported to be formed with the tridentate ligands, H2L (H2L = H2SAE, H2SAP, H2SAPT). In presence of imidazole ligands, the interaction of MoO2(aca)2 and the tridentate ligands form cis-octahedral complexes of the type [MoO2(L)(Im)]. The tetra-, penta and hexadentate ligands H2L - L (H2LL = H2DMED H2DMPD and H2DMDT) react with MoO2(aca)2 to form binuclear and octahedral cis-dioxomolybdenum complexes [(acac)MoO2(L - L)O2Mo(aca)], by the partial replacement of the acac groups from the starting MoO2(acac)2. These complexes have been adequately characterised by ir, nmr (H-1 and C-13), cyclic voltammetric and thermogravimetric measurements.