Phenoxazine‐Sensitized CO2‐to‐CO Reduction with an Iron Porphyrin Catalyst: A Redox Properties‐Catalytic Performance Study. Issue 7 (29th March 2022)

• Record Type: Journal Article
• Authors: Kientz, Martin; Lowe, Grace; McCarthy, Blaine G.; Miyake, Garret M.; Bonin, Julien; Robert, Marc
• Is Part Of: ChemPhotoChem. Volume 6:Issue 7(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-29
• Subjects: carbon dioxide reduction -- carbon monoxide -- molecular catalysis -- phenoxazine -- photosensitizers; Photochemistry -- Periodicals; Periodicals; Electronic journals; 541.35
• DOI: 10.1002/cptc.202200009
• Languages: English
• ISSNs: 2367-0932

Abstract

Abstract: We have evaluated six phenoxazine derivatives as visible light photosensitizers for the photochemical reduction of CO2 to CO with an iron porphyrin catalyst in organic media. The phenoxazine core was functionalized with electron‐donating or ‐withdrawing groups to modify the photophysical properties. Both singlet and triplet excited state potentials of the sensitizers spanned several hundred mV range and the ground state oxidation potentials spanned 250 mV. We observed that no correlation can be established between the production of CO and the excited state potential of the phenoxazine, which determines the driving force for electron transfer to the catalyst. On the contrary, a clear correlation can be made between the oxidation potentials of the phenoxazine and the production of CO. This observation indicates that the process was limited by photosensitizer regeneration and highlights the fact that electron transfers not directly related to the catalyst activation could play a key role in homogeneous photocatalytic systems. Abstract : Pumping iron : The amount of carbon monoxide produced from the photochemical catalytic reduction of carbon dioxide by an iron porphyrin catalyst is limited by the electron transfer regenerating the phenoxazine photosensitizer and not by the driving force of the electron transfer between the excited sensitizer and the catalyst.