Facile transmetalation of a pyridyl-phosphine ligand from ruthenium to gold and silver

Treatment of [RuCl2(η6-p-cymene){κ1-(P)-PPh2(py-6-tert-amyl)}] (1a) and [RuCl2(η3:η3-C10H16){κ1-(P)-PPh2(py-6-tert-amyl)}] (1b) with [AuCl(SMe2)], in dichloromethane at room temperature, resulted in the formation of the dimethyl sulfide adducts [RuCl2(η6-p-cymene)(SMe2)] (3a) and [RuCl2(η3:η3-C10H16)(SMe2)] (3b), and the Au(I) complex [AuCl{κ1-(P)-PPh2(py-6-tert-amyl)}] (4). Transmetalation of the pyridyl-phosphine PPh2(py-6-tert-amyl) (2) was also observed when dichloromethane solutions of 1a–b were treated with AgSbF6 in the presence of SMe2, the reactions leading to 3a–b and the dinuclear Ag(I) derivative [Ag2{μ-PPh2(py-6-tert-amyl)}2][SbF6]2 (5). In the absence of SMe2 transmetalation of the phosphine to silver was not observed. Instead, the unexpected protonation of the pyridyl group by HF, generated by partial hydrolysis of the SbF6− anion, occurred. Compounds [AuCl{κ1-(P)-PPh2(py-6-tert-amyl)}] (4) and [Ag2{μ-PPh2(py-6-tert-amyl)}2][SbF6]2 (5) were independently synthesized by reacting 2 with [AuCl(SMe2)] and AgSbF6, respectively, and their structures confirmed by means of single-crystal X-ray diffraction techniques, along with those of the protonated species [RuCl2(η6-p-cymene){κ1-(P)-PPh2(pyH-6-tert-amyl)}][SbF6] (6a) and [RuCl2(η3:η3-C10H16){κ1-(P)-PPh2(pyH-6-tert-amyl)}][SbF6] (6b).