Aurophilicity at Sulfur Centers. Synthesis and Reactivity of the Complex [S(Au2dppf)]; Formation of Polynuclear Sulfur-Centered Complexes. Crystal Structures of [S(Au2dppf)]·2CHCl3, [(μ-Au2dppf){S(Au2dppf)}2](OTf)2· 8CHCl3, and [S(AuPPh2Me)2(Au2dppf)](ClO4)2·3CH2Cl2

Treatment of [Au 2 Cl 2 (μ-dppf)] (dppf = 1,1‘-bis(diphenylphosphino)ferrocene) with Li 2 S (molar ratio 1:1) in ethanol gives a yellow solid [S(Au 2 dppf)] ( 1 ). The sulfur atom in complex 1 can coordinate several neutral or cationic gold(I) fragments giving the trinuclear neutral [S{Au(C 6 F 5 )}(Au 2 dppf)] ( 2 ) or cationic derivatives [S(AuL)(Au 2 dppf)]ClO 4 [L = CH 2 PPh 3 ( 3 ), PPh 3 ( 4 ), PPh 2 Me ( 5 )]. A pentanuclear complex [Au{S(Au 2 dppf) 2 }]ClO 4 ( 6 ) is obtained by reaction of 2 equiv of complex 1 with 1 equiv of [Au(tht) 2 ]ClO 4, in which the central gold atom is bonded to two sulfur atoms. Treatment of compound 1 with [Au 2 (OTf) 2 (μ-dppf)] (OTf = trifluoromethylsulfonate) in a molar ratio 2:1 affords the hexanuclear complex [(μ-Au 2 dppf){S(Au 2 dppf)} 2 ](OTf) 2 ( 7 ), in which two SAu 3 units are joined through the dppf ligand. The reaction of 1 with 2 equiv of [Au(OClO 3 )PR 3 ] leads to the quadruply bridging derivatives [S(AuPR 3 ) 2 (Au 2 dppf)](ClO 4 ) 2 [PR 3 = PPh 3 ( 8 ), PPh 2 Me ( 9 )]. Crystal structure determinations were performed for complexes 1, 7, and 9 . [S(Au 2 dppf)] ( 1 ) crystallizes in the monoclinic space group P 2/ n, with a = 12.571(4) Å, b = 10.579(4) Å, c = 15.212(4) Å, β = 107.84(3)°, Z = 2, T = −130 °C. [(μ-Au 2 dppf){S(Au 2 dppf)} 2 ](OTf) 2 ( 7 ) is triclinic, P 1̄, with a = 15.177(3), b = 18.408(4), c = 27.894(8) Å, α = 88.83(2), β = 84.46(2), γ = 67.78(2), Z = 2, T = −100 °C. [S(AuPPh 2 Me) 2 (Au 2 dppf)](ClO 4 ) 2 ( 9 ) is triclinic, P 1̄, with a = 13.727(2) Å, b = 15.952(3) Å, c = 17.763(2) Å, α = 71.738(12)°, β = 73.264(14)°, γ = 75.96(2)°, Z = 2, T = −100 °C. All three complexes display short gold(I)−gold(I) interactions.