The replacement of one hydrido-ligand in [(η-C5H5)NiOs3(µ-H)3(CO)9] by MPPh3+(M = Cu or Au). Crystal structure of [(η-C5H5)NiOs3(µ-H)2-(µ-AuPPh3)(CO)9], the first gold–nickel–osmium cluster

Abstract

Abstraction by NaH in tetrahydrofuran of one hydride ligand of [(η-C₅H₅)NiOs₃(µ-H)₃(CO)₉](3) leads to the anion [(η-C₅H₅)NiOs₃(µ-H)₂(CO)₉]^–, which upon reaction with M(PPh₃) Cl (M = Au or Cu) leads to the pentametallic clusters [(η-C₅H₅)NiOs₃(µ-H)₂(µ-MPPh₃)(CO)₉][M = Au, (1); M = Cu, (2)]. The structure of (1) has been determined by X-ray methods. Crystals are triclinic, space group P with Z= 2 in a unit cell of dimensions a= 13.923(3), b= 14.213(4), c= 9.544(4)Å, α= 93.81(4), β= 105.48(2), γ= 102.83(2)°. The structure has been solved from diffractometer data by direct and Fourier methods and refined by full-matrix least squares to R= 0.055 for 2 867 observed reflections. The structure of (1) can be derived from that of (3) by replacing one of the three equivalent hydride ligands by AuPPh₃⁺. The metal cluster can be described as a NiOs₃ tetrahedron with an Os–Os edge bridged by an Au atom.