Transition metal complexes of 2-formylpyridinethiosemicarbazone (HFpyTSC) and X-ray crystal structures of [Pd(FpyTSC)(PPh 3)]PF 6 and [Pd(FpyTSC)(SCN)

Abstract

The syntheses of five new complexes of the 2-formylpyridinethiosemicarbazone ligand (HFpyTSC) with Pd(II) and Rh(III) ions are described, viz., [Pd(FpyTSC)(PPh 3)]PF 6, [Pd(FpyTSC)(SCN)], [Pd(FpyTSC)Br], [Pd(HFpyTSC) 2]Br 2 and [Rh(FpyTSC)(PPh 3) 2Cl]ClO 4. The formulation of the complexes is discussed in terms of their elemental analyses and IR, Raman, NMR ( 1H, 13C and 31P), mass and electronic spectra. The X-ray crystal structures of [Pd(FpyTSC)(PPh 3)]PF 6 and [Pd(FpyTSC)(SCN)] show that the HFpyTSC ligand coordinates to the central Pd(II) ion in a planar conformation through the pyridyl nitrogen, the azomethine nitrogen and the deprotonated thiol sulphur atom. Thus, HFpyTSC is a versatile ligand that usually acts as a mononegative tridentate ligand bonding through N py, N C N and C–S − while, in the case of [Pd(HFpyTSC) 2]Br 2, it behaves as a neutral bidentate ligand via N C N and C S.