Synthesis and Structure of a Cyclic Complex of Digold Sulfide Au₂S and of Related Compounds

Abstract 1,4‐Bis(diphenylphosphanylmethyl)benzene ( 1 ) was converted into its bis[chlorogold(I)] complex [ 1 · (AuCl) 2 ] upon treatment with two equivalents of chloro(dimethyl sulfide)‐gold(I). The reaction of 1 · (AuCl) 2 with one equivalent of silver tetrafluoroborate afforded a cyclic di[gold(I)]chloronium tetrafluoroborate [ 1 · Au 2 Cl + BF ‐ 4 ]. Substitution of chloride in 1 · (AuCl) 2 by sodium methanethiolate in wet chloroform, gave the bis[methylthiogold(I)] complex 1 · (AuSMe) 2 ], while with sodium sulfide a cyclic complex 1 · Au 2 S was obtained. Reaction of 1 · (AuCl) 2 with two equivalents of AgBF 4 followed by treatment with diphenyldisulfide or sodium methanethiolate yielded the cyclic methyl/phenylsulfonium tetrafluoroborates 1 · Au 2 SPh + BF ‐ 4 and 1 · Au 2 SMe + BF ‐ 4 , respectively. All compounds were identified on the basis of their analytical and spectroscopic data. The crystal structures of 1 · (AuCl) 2 , 1 · (AuSMe) 2 , and 1 · Au 2 S have been determined. The Au 2 S complex has a cyclic structure with a narrow Au‐S‐Au angle of 86.7(1)° indicating a significant intraannular Au…Au interaction.