Carbodiphosphorane as an Electron-Donating Ligand for Gold Nanoclusters

A variety of organic ligands such as thiolates, phosphines, alkynyls, <i>N</i>-heterocyclic carbenes, and halides have been widely used to protect gold nanoclusters (AuNCs). The ligands not only determine the stability and solubility but also affect the physicochemical properties of AuNCs. In this regard, the exploration of new ligands is important to further expand the range of properties. In this work, we successfully applied carbodiphosphoranes, known as unique ligands with σ and π donor capabilities, to protect small (<2 nm) AuNCs. X-ray photoelectron spectroscopy and theoretical calculations indicate that AuNCs are negatively charged by electron donation from carbodiphosphorane. These results suggest that novel electron-rich AuNCs can be synthesized by using carbodiphosphoranes as ligands.