Synthesis and Characterization of a Novel Cobalt Carbonyl N-Heterocyclic Carbene Salt. Crystal Structure of [Co(CO)3(IMes)2]+[Co(CO)4]

The disproportionation of dicobalt octacarbonyl induced by the free carbene 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes) and the X-ray characterization of the cyclohexane solvate of the resulting cobalt carbonyl N-heterocyclic carbene salt, [Co(CO)3(IMes)2]+[Co(CO)4] -·1/4C6H12, is reported. The crystal structure represents the first example of a [Co(CO)3(L)2][Co(CO)4] disproportionate salt reported to date.