Cyclopentadienyl-ruthenium and -osmium chemistry. Part 14. The reaction between chloro(cyclopentadienyl)bis(triphenylphosphine)-ruthenium and trifluoroacetonitrile: crystal structure of [RuNHC(CF3)NC(CF3)NH{P(OMe)3}(η-C5H5)]

Abstract

The reaction between CF₃CN and [RuCl(PPh₃)₂(η-C₅H₅)] affords [[graphic omitted]H(PPh₃)(η-C₅H₅)]; exchange with P(OMe)₃ gives the corresponding trimethyl phosphite complex, whose structure has been determined by X-ray diffraction methods. The complex contains a planar metallocycle in which the ruthenium atom is bonded on both sides to NH, then through C(CF₃) to a lone nitrogen atom. The co-ordination around the metal atom is octahedral (with C₅H₅ occupying three sites) and the orthogonality is preserved despite the requirements of the ring geometry. The bonds within the ring are delocalised to give effective mirror symmetry across the Ru…N vector, with mean bond lengths: Ru–NH, 2.078(5); HN–C(CF₃), 1.287(8); (CF₃)C–N, 1.339(9); and C–CF₃, 1.514(11)Å. The angles at N(H) and C(CF₃) adjust to accommodate these rather varied bond lengths, but the angle at the unique N atom remains 120°. Within the cyclopentadienyl ring the Ru–C distances vary between 2.15 and 2.27 Å, the longer ones being trans to the Ru–P bond.