Chemistry of methinyl tricobalt enneacarbonyls. Part13. Preparation and structure of phosphite derivatives, and the crystal and molecular structure of [Co3(CMe)(CO)6{P(OMe)3}3

Abstract

Mono-, di-, and tri-substituted tertiary phosphite derivatives of methinyl tricobalt enneacarbonyls have been prepared. These invariably adopt carbonyl non-bridged structures and are inert to ligand dissociation in solution, in contrast to the previously characterised phosphine derivatives. The crystal and molecular structure of the tri-substituted complex [Co3(CMe)(CO)6{P(OMe)3}3] has been determined from X-ray diffractometer data by direct methods. Crystals are monoclinic, space group P21/c with a= 1 618.7(3), b= 1 470.3(3), c= 1 269.5(3) pm, β= 101.86(1)°, and Z= 4. The structure was refined by full-matrix least squares to R= 0.073 for 2 614 observed reflections. The monomeric structure closely resembles that of the parent compound with the three phosphite ligands occupying equatorial positions on the Co3 triangle. The carbonyl groups are all terminal.