BASIC METALS .16. INTERCONVERSION OF ALKYL-COBALT(III) AND ACYL-COBALT(III) COMPLEXES DERIVED FROM CYCLOPENTADIENYLCARBONYL(TRIMETHYLPHOSPHINE)COBALT(I)

The complex C5H5Co(PMe3CO reacts with alkyl halides to give the acyl complexes C5H5Co(PMe3)(COR)I (R = Me, Et), [C5H5Co(PMe3)(CO)Me]I was shown to be an intermediate in the formation of the acetyl complex, and in solution in more polar solvents the two are in equilibrium, the position of which is dependent upon the solvent polarity. The methyl complex is stable as the PF6 salt in solution, but reacts readily with PPh3 to give [C5H5Co(PMe3)(PPh3)(COMe)PF6. This also exists in solution in equilibrium with the methyl complex and free PPh3, and the equilibrium is almost independent of solvent polarity. With acyl halides, the complexes [C5H5Co(PMe3)(COR)CO]PF6 (R = Me, Et, Ph) are formed. They do not appear to form alkyl complexes under mild conditions. © 1979.