Cationic ruthenium systems. Part 3. Preparation and characterization of cationic dienehydridotris(phosphine)ruthenium complexes: the crystal and molecular structure of (η-buta-1,3-diene)tris(dimethylphenylphosphine)hydridoruthenium(II) hexafluorophosphate

Abstract

The stable salts [RuH(diene)L₃][PF₆]{1; diene = cyclo-octa-1,5-diene (cod), hexa-1,3-diene, or buta-1,3-diene, L = PMe₂Ph; diene = cod, L = P(OMe)₃, P[(OCH₂)₃CMe], PPh₂(OMe), PMe₃, or PMePh₂} have been prepared from the salt [RuH(cod)(NH₂NMe₂)₃][PF₆], and have been characterized by i.r., microanalytical, and ¹H n.m.r. measurements. The crystal structure of [RuH(C₄H₆)(PMe₂Ph)₃][PF₆]·ca. 0.5 CH₂Cl₂ has been determined. The yellow crystals are monoclinic, space group P2₁/n, a= 17.85, b= 18.96, c= 10.31 Å, β= 106.1°. The structure has been solved by the heavy-atom method and refined by least squares to R 0.070 for 2 429 observed data collected on a diffractometer using graphite-monochromatized Mo-K_α radiation. The ruthenium has a distorted-octahedral co-ordination geometry. It is bonded to all the carbon atoms of the butadiene molecule; Ru–C 2.14–2.38 Å. The phosphine ligands have a fac configuration; Ru–P 2.28–2.34 Å, P–Ru–P 94–100°. The butadiene moiety is approximately planar, with bond lengths of 1.48, 1.34, and 1.43 Å(estimated standard deviation 0.03 Å). The position of the hydride ligand is not directly observable but can be inferred from the arrangement of the other ligands in the cation.