Reaction of triphenylphosphine with the anionic cluster [HRu3(CO)11]- revisited: Isolation, crystal structure, and isomerization of [NEt4][HRu3(CO)8(PPh3)(PPhC 6H4)]

Article abstract of DOI:10.1021/om00106a011

The reaction of the cluster anion [HRu₃(CO)₁₁]^- with PPh₃ in refluxing THF results in the formation of the orthometalation product [HRu₃(CO)₈(PPh₃)(PPhC₆H ₄)]^- (3). The cluster anions [HRu₃(CO)₁₀(PPh₃)]^- (1) and [Ru₃(CO)₉(PPh₃)]^2- (2) are supposed to be intermediates in this reaction. The protonation of 3 yields the neutral cluster H₂Ru₃(CO)₈(PPh₃)(PPhC ₆H₄) (4); however, the deprotonation of 4 with potassium selectride gives anion 5, an isomer of 3, differing in the position of the hydride bridge. The structure of 3 was determined by a single-crystal X-ray analysis of the tetraethylammonium salt. Crystals are monoclinic, space group P2₁, with the unit-cell parameters a = 13.250 (4) ?, b = 14.467 (4) ?, c = 12.667 (8) ?, β = 99.97 (2)°, and Z = 2. The structure was solved from diffractometer data by direct and Fourier methods and refined by full-matrix least squares to R = 0.0576 and R_w = 0.0697 for 1339 observed reflections [I ≥ 2σ(I)]. The longest edge of the triangular cluster is bridged by the hydride. The orthometalated phosphinidene ligand interacts with the three metal atoms: the phosphorus bridges two ruthenium atoms, while the third Ru atom is bonded to a carbon atom of the phosphinidene ligand.