Gold(I) Complexes of the Geminal Phosphinoborane tBu2PCH2BPh2

In this work, we explored the coordination properties of the geminal phosphinoborane tBu2PCH2BPh2 (2) toward different gold­(I) precursors. The reaction of 2 with an equimolar amount of the sulfur-based complex (Me2S)­AuCl resulted in displacement of the SMe2 ligand and formation of linear phosphine gold­(I) chloride 3. Using an excess of ligand 2, bisligated complex 4 was formed and showed dynamic behavior at room temperature. Changing the gold­(I) metal precursor to the phosphorus-based complex, (Ph3P)­AuCl impacted the coordination behavior of ligand 2. Namely, the reaction of ligand 2 with (Ph3P)­AuCl led to the heterolytic cleavage of the gold–chloride bond, which is favored over PPh3 ligand displacement. To the best of our knowledge, 2 is the first example of a P/B-ambiphilic ligand capable of cleaving the gold–chloride bond. The coordination chemistry of 2 was further analyzed by density functional theory calculations.