Dithiophosphinates of gold (I); oxidative addition of Cl2to a neutral, dinuclear gold(I) dithiophosphinate complex, and X-ray crystal structures of [AuS2P(C2H5)2]2, [AuS2PPh2]2, Au2(CH2)2PMe2(S2PPh2), and Au2Cl2[(CH2)2PMe2][S2PPh2]

Abstract

The formation and characterization of dinuclear gold(I) dialkyl- and diaryl-dithiophosphinate complexes of the type [AuS2PR2]2are described. The complexes are readily prepared from the reaction between a chloro–gold(I) starting material and the corresponding dithiophosphinate salt. The structures of the complexes show both the absence (R = Et, 1) and presence (R = Ph, 2a) of intermolecular Au···Au interactions as confirmed by X-ray crystallographic study in the solid state. Reaction between [AuS2PPh2]2and [Au(CH2)2PMe2]2in CH2Cl2solution leads to a ligand transfer reaction to form the hetero-bridged complex [Au2{(CH2)2PMe2S2PPh2}] (3a) in high yield. Additionally, the latter complex reacts with Cl2to form the oxidative addition product [Au2Cl2{(CH2)2PMe2S2PPh2}] (4), the first gold(II) complex with a S-P-S bridging moiety. The X-ray crystal structure of both 3a and 4 exhibit rare boat conformations in the solid state, and 4 has a formal Au(II)—Au(II) single bond of 2.5611(5) Å. Reaction between [AuS2PPh2]2and dppm (dppm = Ph2PCH2PPh2) leads to a sparsely soluble three-coordinate dinuclear gold(I) complex with the molecular formula [Au2{dppmS2PR2}2]n(n = 1 or [Formula: see text]) (5).Key words: dithiophosphinates, ylide, dithiols, gold-gold bond.