In Situ Formation of PBiP Ligands upon Complexation of a Mixed Phosphane/Bismuthane with Group 11 Metal Ions.

The behavior of a xanthene derivative with one bismuthane and one phosphane function, Xan(PPh2)(BiPh2), as a ligand toward group 11 metal cations was investigated. It was found that contact with [Cu(MeCN)4]OTf, AgOTf, [Au(PPh3)OTf], in all three cases leads to a transformation of Xan(PPh2)(BiPh2) into a tridentate PBiP system, where a BiPh unit connects two phosphinoxanthyl moieties. In the resulting compounds, [PhBi(Xan(PPh2))2Cu]OTf, 1, [PhBi(Xan(PPh2))2Ag]OTf, 2, and [PhBi(Xan(PPh2))2AuPPh3]OTf, 3, the metal cations are coordinated tetrahedrally by two phosphane donors, one bismuthane donor and a fourth ligand, corresponding to OTf- in case of 1 and 2, or PPh3 in the case of 3. DFT calculations in combination with NBO analysis showed that the bismuth atoms in these PBiP ligands act as σ-donors. 3 thus corresponds to the first known AuI ← BiIII complex. [ABSTRACT FROM AUTHOR]