PHOTOELECTROCHEMISTRY OF SOME ORGANOCHROMIUM CARBONYL-COMPOUNDS

The dual photochemical and electrochemical activation of three different organochromium carbonyl species have been studied. For each of [Cr(CO),], trans-[Cr(CO)2(dppe)2]+ [dppe = 1,2-bis(diphenylphosphino)ethane] and [Cr(CO)3(eta6-C6Et6)] the photo-oxidation has been studied and it is demonstrated that the course of the reaction in the presence of light, and its kinetics, may be studied using channel-electrode voltammetry. In the case of [Cr(CO)6] and [Cr(CO)3(eta6-C6Et6)] electron transfer to the electrode follows photochemical reaction and it is shown that the occurrence of photosubstitution in the former, and photofragmentation in the latter modifies the pathway of the electrode reaction. For trans-[Cr(CO)2(dppe)2]+ photochemical reaction is only seen after electro-oxidation and this is demonstrated to lead to a disproportionation reaction.