The electrochemical preparation of [Au9(PPh3)8]+. A comparative study of the structures and properties of [Au9(PPh3)8]+ and [Au9(PPh3)8]3+

[Au9L8]PF6 (L = PPh3) deposits on the cathode during the coulometric two-electron reduction of [Au9L8](PF6)3 in acetonitrile at constant potential (−0.60 V relative to an Ag/AgCl electrode). X-ray crystal structure determination shows a centred cubic arrangement of the 9 Au atoms in the cluster. Physical data, including (solid state) 31P[1H]NMR and 197Au Mossbauer data, are provided and compared with those of [Au9L8]3+.