TRANSITION-METAL COMPLEXES WITH HYDRAZIDES AND HYDRAZONES .7. DIOXOMOLYBDENUM(VI) COMPLEXES OF SALICYLALDEHYDE P-HYDROXYBENZOYLHYDRAZONE AND THEIR THERMAL-STABILITY

Several new complexes of dioxomolybdenum(VI) of the general formula [M oO2(L)S], where L is the dianion of salicylaldehyde p-hydroxybenzoylhy drazone and S denotes H2O, MeOH, py, PPh(3), DMSO or DMF, were synthes ized and characterized by elemental analysis, electronic UV-VIS and IR spectra, thermal analysis, molar conductivity and magnetic susceptibi lity measurements. Salicylaldehyde p-hydroxybenzoylhydrazone participa tes in the coordination as a tridentate ligand with the ONO set of don or atoms. The complexes contain a cis-MoO2 group and are of octahedral geometry. Complexes of the MoO(2)L type were also prepared by synthes is in CHCl3 solution and by isothermal heating of[MoO2(L)S] complexes. The MoO(2)L complex synthesized in CHCl3 solution has most probably a pentacoordinated structure while the complex obtained by isothermal h eating of [MoO2(L)S] has a polymeric hexacoordinated structure.