SYNTHESIS AND CHARACTERIZATION OF MOLYBDENUM AND TUNGSTEN COMPLEXES OF 1-ARYL-2,4-DITHIOBIURETS

Several molybdenum and tungsten 1-aryl-2,4-dithiobiuret complexes of the type M2O4L2(H2O)2 [where M = Mo(V) or W(V), LH = 1-phenyl-2,4-dithiobiuret (PDTBH), 1-methylphenyl-2,4-dithiobiuret (MePDTBH), 1-p-methoxyphenyl-2,4,-dithiobiuret (MeOPDTBH) and 1-p-chlorophenyl-2,4,-dithiobiuret (ClPDTBH) have been synthesized and characterized. Molar conductance measurements in DMF show non-ionic behaviour for all complexes. Magnetic susceptibility measurements indicate diamagnetic behaviour of the complexes. On the basis of electronic spectral studies, an octahedral environment around the M(V) ion has been suggested. IR spectral studies, together with electronic spectra, are indicative of dinuclear-type complexes possessing a M2O4 2+ moiety. The complexes were found to be ESR-inactive. A monoanionic bidenate mode of bonding has been inferred on the basis of IR spectral studies. X-ray powder diffraction of the complexes shows their amorphous nature. 1H NMR and 13C NMR spectra of the metal complexes of 1-phenyl-2,4-...