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

Abstract

Polynuclear [MoO 2{SalTSC-4-Me}] n ( I), [MoO 2{VanTSC-4-Me}] n ( II) and mononuclear [MoO 2{SalTSC-4-Me}(CH 3OH)] ( 1a), [MoO 2{VanTSC-4-Me}(CH 3OH)] ( 2a) and [MoO 2{VanTSC-4-Me}(H 2O)] · CH 3CN ( 2b) complexes have been prepared by the reaction of the [MoO 2(acac) 2] (acetylacetonate ligand, acac −, C 5H 7O 2 −) with 1 (salicylaldehyde 4-methylthiosemicarbazone ligand, C 6H 4(OH)CH:NNC(SH)NHCH 3H 2SalTSC-4-Me) or 2 (3-methoxy-salicylaldehyde 4-methylthiosemicarbazone, CH 3OC 6H 3(OH)CH:NNC(SH)NHCH 3, H 2VanTSC-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 1H, 13C 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 1H, 13C NMR spectroscopy and X-ray crystallography. Molecules of both ligands are found to be in the thioketo tautomeric form.