The X-ray crystallographic study of the reaction of bis(2-thienyl)ditelluride with tetrakis(triphenylphosphine)platinum or -palladium

The oxidative addition of dithienyl ditelluride to [Pt(PPh3)4] in dichloromethane results in the formation of a trinuclear complex [Pt3Te2(Th)(PPh3)5]Cl (Th=2-thienyl, C4H3S) (1) as well as a mononuclear complex [PtCl(Th)(PPh3)2] that have been identified and structurally characterized by X-ray crystallography and 31P-NMR spectroscopy. The analogous reaction involving [Pd(PPh3)4] forms a mixture of several products. In dichloromethane [Pd6Cl2Te4(TeTh)2(PPh3)6] (2) can be isolated and its X-ray structure determined. In toluene [Pd6Te4(TeTh)4(PPh3)6] (3) is formed. Both 2 and 3 have a similar hexanuclear framework which has previously been reported for [Pd6Te6(PEt3)8] in the literature. These products indicate that the cleavage of both TeTe and CTe bonds as well as the choice of the solvent play an important role in the oxidative addition. The trinuclear and hexanuclear complexes can be considered to be formed from an initial mononuclear addition product. The reaction pathways are compared to those involved in the reaction of Th2Se2 and [M(PPh3)4] (M=Pt, Pd).