Iron complexes are promising alternatives to precious-metal photosensitizers, but rapid excited-state relaxation often limits their reactivity. This seminar will discuss a recent study that combines ligand design and organization within micelles to promote electron transfer from a short-lived upper excited state of an iron(II) complex. Spectroscopic and electrochemical evidence for this pathway will be examined, along with the limitations of the proposed mechanism. The study highlights how both excited-state energy and reaction kinetics determine whether absorbed light can drive a chemical reaction.

Ghosh, A.; Pfund, B.; Yarranton, J. T.; Lien, Y.-J.; McCusker, J. K. Kinetics vs Thermodynamics: Engineering Photoredox Reactivity from an Upper Excited State of Feᴵᴵ. J. Am. Chem. Soc. 2026, 148, 23879–23890.