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.