Synthesis of the anion [Ru3H(µ3-PPh)(CO)9]– and its reactions with complexes of Re, Rh, Ir, Cu, Ag, and Au to give heterometallic clusters containing a triruthenium unit: crystal structures of the complexes [Ru3Rh2(µ4-PPh)(CO)13(PEt3)] and [Ru3{µ-Au(PMe2Ph)}(µ-H)(µ3-PPh)(CO)9]

Abstract

Deprotonation of [Ru₃H₂(µ₃-PPh)(CO)₉] with base gives the anion [Ru₃H(µ₃-PPh)(CO)₉]^– which has been isolated as its [N(PPh₃)₂]⁺ salt. This anion reacts with cationic complexes of Re, Rh, Ir, and Au, and with [{Cul(PEt₃)}₄] and [{Agl(PEt₃)}₄], to give heterometallic complexes containing a triruthenium unit. With Re, Rh, Ir, Cu, Ag, and Au, tetranuclear complexes are obtained and structures in which the heterometal atom (M′) either bridges one edge of [M′= Cu, Ag, or Au] or caps the Ru₃ triangle [M′= Re, Rh, or Ir] are proposed. In the case of the gold complex, [Ru₃{µ-Au(PMe₂Ph)}(µ-H)(µ₃-PPh)(CO)₉], this proposal has been confirmed by an X-ray analysis. This complex crystallises in space group P2₁/c with a= 8.805(3), b= 20.195(7), c= 16.683(6)Å, β= 100.62(2)°, and Z= 4. The structure was solved by a combination of direct methods and Fourier-difference techniques, and refined by blocked-cascade least squares to R= 0.067 for 1 398 unique diffractometer data with F > 5σ(F). The reaction of the triruthenium anion with [Rh(CO)₃(PR₃)₂]⁺(R = Et or Ph) gives, in addition to the tetranuclear complexes, the pentanuclear complexes [Ru₃Rh₂(PPh)(CO)₁₃(PR₃)]. An X-ray analysis of the complex with R = Et reveals a square-pyramidal array of metal atoms with a µ₄-PPh ligand capping two of the Ru and the two Rh atoms to give an overall distorted octahedral geometry. This complex crystallises in space group C2/c with a= 20.257(5), b= 9.679(3), c= 34.726(5)Å, β= 90.24(2)°, and Z= 8. The structure was solved using the same techniques as for the Ru₃Au complex and refined to R= 0.034 for 4 708 diffractometer data with F > 6σ(F).