Gold(I) dimethyl- and diphenyl-dithiophosphinate complexes

Abstract

In an attempt to carry out polyauration of dithiophosphinate units, diphenyldithiophosphinic acid, Ph2P(S)SH, was treated with the reagents {[(R′3P)Au]3O}+BF4– to give compounds {Ph2P[SAu(PR′3)]2}+BF4– with R′ = Ph, Me or o-tolyl (o-Tol) (1–3). The symmetrical Au· · ·Au bonded structure of complex 1 was confirmed by a single-crystal X-ray diffraction study. Intercationic contacts are found only between gold and sulfur atoms. The analogous reaction with PhP(S)(SSiMe3)2 gave an unstable product of the composition {PhP[SAu(PPh3)]3}+BF4–4, for which a solution structure with mirror-symmetry is proposed on the basis of low-temperature NMR data. Attempts to polyaurate dimethyldithiophosphinic acid led to cleavage of the P–S bonds with formation of known trigold sulfonium salts. (Phosphine)gold(I) dithiophosphinates Me2P(S)SAu(PR′3) were obtained from Me2P(S)SNa and chloro(phosphine)gold complexes (R′ = Me, Ph or o-Tol, 5–7 respectively). The crystal and molecular structure of compound 5 was determined. In the crystal, the compound forms two crystallographically independent, centrosymmetrical dimers with Au· · ·Au contacts [3.1152(5) and 3.1466(5) A] between ‘crossed’ monomers. With (Me2S)AuCl as a precursor, the product of the reaction with Me2P(S)SNa was [Me2P(S)SAu]28. Compound 8 is a dinuclear complex with an elongated eight-membered ring structure in a chair conformation. The crystal-structure analysis reveals the expected transannular Au· · ·Au contacts [3.1949(9) A], but no intermolecular contacts are discernible.