Synthesis of five new molybdenum(VI) thiosemicarbazonato complexes. Crystal structures of salicylaldehyde and 3-methoxy-salicylaldehyde 4-methylthiosemicarbazones and their molybdenum(VI) complexes

Polynuclear [MoO2{SalTSC-4-Me}](n) (1), [MoO2{VanTSC-4-Me}](n) (II) and mononuclear [MoO2{SaITSC-4-Me}(CH3OH)] (1a), [MoO2{VanTSC-4-Me}(CH3OH)] (2a) and [MoO2{VanTSC-4-Me}(H2O)]center dot CH3CN (2b) complexes have been prepared by the reaction of the [MoO2(acac)(2)] (acetylacetonate ligand, acac(-), C5H7O2-) with 1 (salicylaldehyde 4-methylthiosemicarbazone ligand, C6H4(OH)CH:NNC(SH)NHCH3, H(2)VanTSC-4-Me) or 2 (3-methoxy-salicylaidehyde 4-methylthiosemicarbazone, CH3OC6H3(OH)CH:NNQSH)NHCH3, H2VanTSC-4-Me) in acetonitrile or in dry methanol. All complexes have been characterized by means of chemical analyses, thermogravimetric analyses, IR spectroscopy and some of them by H-1, C-13 NMR spectroscopy and X-ray crystallography. In all mononuclear complexes molybdenum atom is coordinated by two terminal oxo-oxygen atoms, by ONS atoms from the ligand molecule and by an oxygen atom from methanol (in 1a and 2a) or water (in 2b) molecules. Ligands 1 and 2 have been characterized by means of H-1, C-13 NMR spectroscopy and X-ray crystallography. Molecules of both ligands are found to be in the thioketo tautomeric form. (c) 2005 Elsevier Ltd. All rights reserved.