Multinuclear magnetic resonance studies on the interactions of platinum bis(dithiolates) with potentially tridentate phosphine ligands

Abstract

The reactions of platinum(II) dithiolates Pt(S-S) 2 (S-S=S 2P(OEt) 2, S 2CO nPr, S 2CNEt 2) with two potentially tridentate phosphine ligands have been investigated by multinuclear magnetic resonance spectroscopy. The phosphines used were Ph 2PCH 2CH 2P(Ph)CH 2CH 2PPh 2 (P 2P′) and CH 3C(CH 2PPh 2) 3 (P 3). P 2P′ reacts with all the dithiolates to give complexes of the type [(η 3-P 2P′)Pt(S-S)] + which are thought to be square planar. A square planar complex (η 2-P 2P′)Pt(η 2-S 2P{O}OEt) can be identified at low temperature. In contrast, P 3 acts only as a bidentate ligand in these systems to give square planar complexes of the type [(η 2-P 3)Pt(η 2-S-S)] + which are fluxional at room temperature. Various reactions can be carried out with the pendant phosphine, such as reaction with sulfur and methylation, and these stop the ligand exchange reactions.