Six-coordinate ruthenium(II) complexes containing both formate and alkenyl ligands. Crystal structure of Ru(O<inf>2</inf>CH)(CO)(HCCHPh)(PPh<inf>3</inf>)<inf>2</inf>

The formate complexes Ru(O2CH)(CO)(RCCHR′)(PPh3)2 have been obtained in qantitative yield from the reaction of the unsaturated complexes Ru(CO)Cl(RCCHR′)(PPh3)2 with sodium formate in CH2Cl2/MeOH mixtures. The synthesized complexes contain the formate ligand η2-coordinated to metal. The structure of the complex Ru(O2CH)(CO)(HCCHPh)(PPh3)2 has been established by an X-ray diffraction study. The molecule consist of an distorted octahedral ruthenium atom coordinated by two PPh3 ligands in the axial positions and the other ligands in the equatorial plane. The η2-coordinated formate ligand is not symmetric, and has CO distances of 1.21(2) and 1.43(2) Å. © 1991.