Cationic Copper Hydride Clusters Arising from Oxidation of (Ph3P)6Cu6H6

Transfer of the first electron from (Ph3P)6Cu6H6 to Cp*2Fe+ is fast (k > 106 L·mol–1·s–1). Transfer of a second electron to the same oxidant has a much lower thermodynamic driving force and is considerably slower, with k = 9.29(4) × 103 L·mol–1·s–1. The second oxidation leads to the formation of [(Ph3P)6Cu6H5]+. The structure of [(Ph3P)6Cu6H5]+ has been confirmed by its conversion back to (Ph3P)6Cu6H6 and by microanalysis; X-ray diffraction shows that the complex is a bitetrahedron in the solid state. [(Ph3P)6Cu6H5]+ can also be prepared by treating (Ph3P)6Cu6H6 with MeOTf. With less than 1 equiv of Cp*2Fe+ as oxidant, (Ph3P)6Cu6H6 gives [(Ph3P)7Cu7H6]+ as the major product; X-ray diffraction shows a Cu6 octahedron with one face capped by an additional Cu. [(Ph3P)7Cu7H6]+ can also be prepared by treating (Ph3P)6Cu6H6 with [Cu(CH3CN)4]+ (along with 1 equiv of Ph3P), and can be converted back to (Ph3P)6Cu6H6 with base/H2.