Gold Coordination by Tertiary Phosphane Sulfides

Article abstract of DOI:10.1002/cber.19971300723

Treatment of the ditertiary phosphane sulfides (CH₂)_n[PPh₂S]₂, 1a-1d, n = 1-4, with equivalent amounts of (dimethylsulfide)gold(I) chloride (Me₂S)AuCl affords the dinuclear complexes 2a-2d with an AuCl unit attached to each sulfur atom. The chlorides can be converted into the bromides 3a-3c by metathesis using KBr, or by reacting Id with (tetrahydrothiophene)gold bromide. With [(Ph₃P)Au]⁺ O₃SCF₃^- as the aurating agent for the diphosphane disulfides, the corresponding dicationic products are obtained: {(CH₂)_n[SPPh₂AuPPh₃] ₂}²⁺·2 O₃SCF₃^- (4b-4d, n = 2-4). An excess of the reagents does not lead to polygold clustering at the sulfur atoms, and P-S cleavage occurs instead to give sulfonium salts {S[Au(PPh₃)]₃)⁺ X^-. The reaction of Ph₃PS with equimolar quantities of [(Ph₃P)Au]O₃SCF₃ leads to the cationic 1:1 complex 5, and with an excess of the agent the P-S bond is ruptured. The structures of compounds 4b and 4d were determined by single-crystal X-ray diffraction. The dications have crystallographic centers of inversion, the coordination at the gold atoms is linear [4b: 179.03(3)°; 4d: 175.29(2)°] and the angles at the sulfur atoms are acute [4b: 97.76(4)°; 4d: 96.37(3)°], but there are no short Au-Au contacts. VCH Verlagsgesellschaft mbH,.