X-ray crystallographic study of a trinuclear ruthenium organo-metallic complex.
Loading...
Date
1984
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The crystal structure of Ru₃ (C0)₁₀(C₆H₅)₂PN(C₂H₅) P(C₆H₅)₂ (RUC)PNP) has been determined by single crystal X-ray analysis. The crystals are tri-- clinic with space group PĪ. The unit cell of dimensions a = 14,732; b = 12,386; c = 10,982 Å; α = 104,52; β = 100,64; γ = 94,89° contains
two formula units. The unit cell and space group were determined by photographic deJong-Bouman and precession techniques using CuKα radiation. A procedure was developed for more accurate alignment of the crystal for rotating crystal techniques. Intensity data were collected on a Philips PW1100 four-circle diffractometer with MoKα radiation. The positions of the Ru atoms were determined from Patterson syntheses and the remaining
atoms located using successive Fourier synthesis. The structure was refined by blocked full-matrix least-squares methods to a residual of R = 0,0537 for 3538 independent reflections with I > 5σ(I) with 300 parameters in the final refinement. The phenyl rings and the CH₂ and CH₃ moities were refined as rigid groups with H-atoms included at fixed
positions. A difference Fourier synthesis was done and showed no significant peaks. RUCOPNP is derived from Ru₃(CO)₁₂ by substitution of two equatorial carbonyl ligands by the P atoms of a single edge-bridging (C₆H₅)₂PN(C₂H₅)P(
C₆H₅)₂ ligand (PNP). In both complexes the Ru atoms are arranged in a triangle and have distorted octahedral geometry. The introduction of the PNP ligand to the symmetrical parent Ru₃(CO)₁₂ has the following effects:
(a) It causes a contraction of the ligand-bridged Ru-Ru bond distance to 2,798 Å whereas the other Ru-Ru distances are 2,860 and 2,848 Å which are close to the distances in the parent compound; (b) It causes the
adjacent equatorial carbonyl ligands to rotate towards the PNP ligand by 11,4°. (c) It causes considerable deviations of some of the axial carbonyl ligands from the normal to the plane containing the Ru atoms.
Description
Thesis (M.Sc.)-University of Durban-Westville, 1984.
Keywords
Ruthenium., Theses--Physics.