Towards Alternatives to Anodic Water Oxidation: Basket-Handle Thiolate FeIII Porphyrins for Electrocatalytic Hydrocarbon Oxidation

Selective electrocatalytic oxidation of hydrocarbons to alcohols, epoxides or other (higher value) oxygenates should in principal present a useful complementary anodic half-cell reaction to cathodic generation of fuels from water or CO2 viz. an alternative to oxygen evolution. A series of new basket-handle thiolate FeIII porphyrins have been synthesised and shown to mediate anodic oxidation of hydrocarbons, specifically adamantane hydroxylation and cyclooctene epoxidation. We compare yields obtained by electrochemical and chemical oxidation of the thiolate porphyrins and benchmark their behaviour against that of FeIII tetraphenyl porphyrin chloride and its tetrapentafluorophenyl analogue.