DITHIOLATES AS BRIDGING LIGANDS IN DINUCLEAR AND TRINUCLEAR GOLD COMPLEXES - X-RAY STRUCTURES OF [AU2(3,4-S2C6H3CH3)(PPH3)2], [AU2(1,3-S2C6H4)(PPH3)2], [AU3(3,4-S2C6H3CH3)(PPH3)3]CLO4, AND [AU(PPH2ME)2][AU(3,4-S2C6H3CH3)2]

The reaction of [AuCl(AsPh3)] with potassium 1,2-benzenedithiolate or 3,4-toluenedithiolate (2:1 ratio) leads to [Au2(S-S)(AsPh3)]n [S-S = 1,2-S2C6H4 (1), 3,4-S2C6H3CH3 (2)] but with 1,3-benzenedithiolate the homoleptic [Au2(1,3-S2C6H4)]n(3) is obtained. Other dinuclear complexes have been prepared by reacting 1-3 with phosphines, namely [Au2(S-S)(PR3)2] [S-S = 1,2-S2C6H4 (4, 5), 3,4-S2C6H3CH3 (6, 7), 1,3-S2C6H4(8, 9); PR3 = PPh3, PPh2-Me]. The reaction of [Au2(S-S)(PPh3)2] (4 and 6) with equimolecular amounts of [Au(PPh3)(acetone)] ClO4 affords the trinuclear complexes [Au3(S-S)(PPh3)3] ClO4 [S-S = 1,2-S2C6H4 (10) and 3,4-S2C6H3CH3 (11)]. Gold-(I)/gold(III) complexes [Au(PR3)2][Au(3,4-S2C6H3CH3)2] [PR3 = PPh3 (12), PPh2Me (13)] have been obtained as byproducts in the preparation of 6 and 7. X ray structure determinations were performed for complexes 6, 8, 11 and 13. Complex 6 crystallizes in the space group P2(1), monoclinic, with a = 10.771(4) angstrom, b = 10.726(3) angstrom, c = 16.752(6) angstrom, beta = 101.02(3)-degrees, and Z = 2. Compound 8 crystallizes in space group Fdd2, orthorhombic, with a = 31.182(8) angstrom, b = 46.537(12) angstrom, c = 8.782(3) angstrom, and Z = 16. Complex 11 crystallizes in space group C2/c, monoclinic, with a = 39.583(8) angstrom, b = 11.347(3) angstrom, c = 31.703(7) angstrom, beta = 120.66(2)-degrees, and Z = 8. Compound 13 crystallizes in space group C2/c, monoclinic, with a = 17.890(7) angstrom, b = 11.038(6) angstrom, c = 20.817(11) angstrom, beta = 110.96(3)-degrees, and Z = 4. Short Au...Au contacts (ca. 3 angstrom) are observed in 6 and 11 (intramolecular) and 8 (intermolecular). Complexes 6 and 11 also display intramolecular Au-S contacts of ca. 2.6-2.7 angstrom, leading to an increase of coordination number (to 3) at Au(1) in 6 and Au(2) in 11.