Synthesis, spectroscopic and electrochemical characterisation of binuclear dioxomolybdenum complexes derived from disalicylaldehyde succinoyldihydrazone

The diamagnetic dioxomolybdenum (VI) complexes [(MoO2)2(L).(H2O)2] where H4L = H4slsh have been isolated in solid state from the reaction of MoO2(acac)2 and disalicylaldehyde succinoyldihydrazone (H4L) in 3:1 molar ratio in ethanol at higher temperature. The reaction of the complex with electron donor bases gives diamagnetic molybdenum(VI) complexes having composition [(MoO2)2(L)(A)2]·H2O (where A = pyridine (py, 2), 2-picoline (2-pic, 3), 3-picoline (3-pic, 4), 4-picoline (4-pic, 5). The composition of the complexes have been established by analytical, thermo-analytical data. The structure of the molybdenum (VI) complexes has been established by mass, electronic, IR, 1H NMR and CV spectral studies. The dihydrazone is coordinated to the metal centres in staggered configuration in all the complexes. The electronic spectra of the complexes are dominated by strong charge transfer bands. All of the complexes involve six coordinated molybdenum centre with octahedral arrangement of donor atoms.