[LNTH]

I've been reading about Cobalt C-H activation reactions and wondering about the oxidation states.

In high valent Co(III) C-H activations Cp*Co complexes are largely used.

In most papers, I see [Cp*Co(CO)I2] and [Cp*CoCl2}2] (dimeric complex) as pre-catalyst turning into a cationic complex with AgSbF6 additives, or in some cases cationic Co as [Cp*Co(C6H6)][B(C6F5)4]2 is used.

I know that Cp* can give 5 or 6 electrons and Iodine sometimes give 2 or 1 electrons but in this case, considering the 18e rule, how can I count electrons and figure out Co oxidation states?

[chenbeier]

The oxidation state is only driven by the anions.

[Cp*Co(CO)I2]  Co²⁺ becuse 2 I^-
[Cp*CoCl2}2] (dimeric complex) Co²⁺ because of 2 Cl^-
[Cp*Co(C6H6)][B(C6F5)4]2 Co²⁺ because 2 [B(C₆F₅)₄]^-

Cp, C₆H₆ and CO, are neutral ligands.