SYNTHESIS AND STRUCTURE OF Ru(CO)4. THE CONFORMATION OF THE TRIMETHYL PHOSPHITE LIGAND IN COMPLEXES.

Article abstract of DOI:10.1016/S0022-328X(00)93389-8

Two methods of preparation of Ru(CO)4 from Ru3(CO)12 and P(OCH3)3 are described.The crystal structure of the compound has been determined from three-dimensional X-ray data collected by counter methods.The space group is P2₁/c with cell dimensions a 13.225(3), b 7.704(3), c 13.278(4) Angstroem and β 109.82(2)^o.Intensity data for 1879 observed reflections were refined by conventional methods to R=0.044.The structure shows that the phosphite ligand does not have three fold symmetry.From a comparison of the infrared spectrum in the carbonyl region of Ru(CO)4 with that of the corresponding P(OCH2)3CC2H5 derivative it is concluded that the asymmetry of the ligand is maintained on the infrared time scale.The 13C and 1H NMR spectra however indicate the methyl groups are all equivalent on the NMR time scale, even at -120 deg C.The NMR study also indicated there is rapid exchange of the axial and equatorial carbonyl groups in solution.