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.