Iron-based catalysts for light-driven water oxidation

Our project

Very recently mononuclear iron complexes with tetraazadentate ligands have been reported to be active water oxidation catalysts. Iron is a very attractive metal to use for water oxidation catalysis based on its availability and non-toxicity. The reported catalysts uses a strong chemical oxidant, cerium(IV) and has a relatively large over-potential for water oxidation.

We have used polypyridyl ligands to make mononuclear iron catalysts for water oxidation. Based on a ligand system already reported for a cobalt-based water oxidation catalyst we have identified a mononuclear iron complex that can be driven by light energy using a photosensitizer and electron acceptor as described above for the cobalt catalysts. Interestingly the ligand appears to not be as innocent as originally thought and we have indications that the ligand takes active part in the catalysis by opening a binding site for a water molecule. Together with Marcus Lundberg’s group at Theoretical Chemistry we are investigating this system using DFT calculations.