Heteropolynuclear complexes with the ligand Ph2PCH2SPh: theoretical evidence for metallophilic Au-M attractions

Addition of two equivalents of diphenylthiomethylphosphine (PPh2-CH2SPh) to the starting materials Au(tht)2]A (tht = tetrahydrothiophene), AgCF3SO3, or Cu(CH3CN)4]CF3SO3 produces the mononuclear derivatives M(PPh2CH2SPh)2]A (M = Au, A = CF3SO3 (1a); M = Au, A = ClO4 (1b); M = Ag, A = CF3SO3 (4); M = Cu, A = CF3SO3 (5)) which are able to form the heterodinuclear complexes AuM'(PPh2CH2SPh)2](CF3SO3)2 (M' = Ag (2), Cu (3)) with a P-Au-P environment. If the starting gold complex is Au(C6F5)(tht)], reaction with the phosphine produces Au(C6F5)-(PPh2CH2SPh)] (6) from which, by reaction with AgCF3SO3 or Cu(CH3CN)4]CF3SO3, the "snake"-type linear complexes Au2M(C6F5)2-(PPh2CH2SPh)2]CF3SO3 (M = Ag (7), Cu (8)) are obtained. If the silver starting complex is AgCF3CO2, reaction in a 1:1 ratio gives the tetranuclear complex Au2Ag2(C6F5)2(PPh2CH2SPh)2-(CF3CO2)2] (9). When the molar ratio is 1:2 the trinuclear complex AuAg2(C6F5) (CF3CO2)2(PPh2CH2SPh)] (10) is obtained. According to ab initio calculations, the presence of only one gold atom is enough to induce metallophilic attractions in the group congeners, and this effect can be modulated depending on the gold ligand.