Platinum(II), palladium(II) and gold(III) complexes containing 1,1,4-trisubstituted thiosemicarbazide dianion ligands

Abstract

Reactions of cis-[PtCl₂(PPh₃)₂] or [PdCl₂(PPh₃)₂] with Ph₂N---NHC(S)NHPh and excess triethylamine, in refluxing methanol gave the complexes [M{SC(=NPh)NNPh₂}(PPh₃)₂] containing thiosemicarbazide dianion ligands. An analogous gold(III) complex containing the cyclo-aurated anilinopyridine ligand was also synthesised. A single crystal X-ray diffraction study was carried out on the complex [Pt{SC(=NPh)NNPh₂}(PPh₃)₂] which confirmed the bonding of the thiosemicarbazide dianion ligand via sulfur and the nitrogen bearing the NPh₂ substituent. In contrast, reaction of Ph₂N---NHC(S)NHMe with cis-[PtCl₂(PPh₃)₂] and excess triethylamine gave the complex [Pt{SC(=NNPh₂)NMe}(PPh₃)₂], containing a Pt---NMe group, characterized spectroscopically.