THE CRYSTAL AND MOLECULAR STRUCTURE OF THE VIOLET ISOMER OF (⊘P)2[(CF3)2C2S2] RuCO

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Abstract
The crystal structure and the details of the molecular configuration of the violet isomer of (⊘3 P)2 [(CF3)2 C2 S2] -RuCO were established from three dimensional, single crystal, X-ray diffraction data. This isomer crystallizes in the orthorhombic system, space group D15 2h-Pbca, in a cell whose dimensions are: a = 22.394(8), b = 19.107(6) and c = 17.480(5)Å. The measured and calculated densities are 1.56(2) and 1.56 gm-cm−3 and z = 8 molecules/ unit cell. The shape of the polyhedron of ligands around the central Ru atom is a square pyramid distorted principally by the fact that the Ru—C bond length is shorter than the four bonds to the nearly equidistant phosphorus and sulfur ligands. The dithiolene sulfur atoms occupy adjacent positions in the basal plane; the two triphenylphosphine ligands occupy a basal plane site and the unique axial position while the carbonyl carbon occupies the fourth basal plane site. The two Ru—S bond lengths are 2.298(3) and 2.287(3) Å, while the two Ru—P distances are 2.353(3) and 2.274(3) A in length, the latter being the basal plane Ru—P bond. The Ru—C and C—O bond lengths are 1.849(11) and 1.133(11) Å, respectively. The bonds within the triphenylphosphines are normal and the phenyl rings are planar, nearly equilateral hexagons. The dithiolene ligand has C—S and (ethylene C)—(ethylene C) distances of 1.719(10) and 1.358(12) Å, respectively, which conform more closely to values expected from an unsaturated cis-dithiol than a dithioketone. The closest inter or intramolecular contact between the Ru atom and the phenyl hydrogens is 3.08 A, which is about 0.5 Å longer than the sum of van der Waals' radii. When refinement was complete, the unweighted and weighted R(F) factors, for 2386 observed reflections, were 0.060 and 0.055, with an error of fit of 1.16.