Dithiophosphinates of gold(I); oxidative addition of Cl2 to a neutral, dinuclear gold(I) dithiophosphinate complex, and X-ray cristal structures of [AuS2 P(C2H5)2)]2, [AuS2PPh2]2, Au2(CH2)2PMe2(S2PPh2) and Au2Cl2[(CH2)2PMe2][S2PPh2]

Resumen

The formation and characterization of dinuclear gold(I) dialkyl- and diaryl-dithiophosphinate complexes of the type [AuS2PR2]2 are 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]2 and [Au(CH2)2PMe2]2 in CH2Cl2 solution leads to a ligand transfer reaction to form the hetero-bridged complex [Au2{(CH2)2PMe2}{S 2PPh2}] (3a) in high yield. Additionally, the latter complex reacts with Cl2 to form the oxidative addition product [Au2Cl2{(CH2)2PMe2}{S 2PPh2}] (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]2 and dppm (dppm = Ph2PCH2PPh2) leads to a sparsely soluble three-coordinate dinuclear gold(I) complex with the molecular formula [Au2{dppm}{S2PR2}2]n (n = 1 or ∞) (5).