Research Projects

Dioxygen, a crucial molecule for survival, plays a crucial role in biological processes and is considered the greenest oxidant. Triplet O₂ is unreactive due to its high negative reduction potential, but nature can overcome spin state barriers by involving metalloenzymes that can directly react with it. Iron-containing metalloenzymes, both heme and non-heme, can catalyze selective oxidation reactions through the formation of highly reactive iron-oxygen intermediates. Biomimetic functional models have been developed to generate such intermediates using different chemical oxidants, O₂ with an electron and proton donor, or water as an oxygen source. Light irradiation can provide a clean and mild reaction condition for organic transformations. Photoredox catalysis operates on the principle of activating reactants through photo-induced electron transfer. This study proposes photocatalytic activation of O₂ by non-heme iron(II) complexes, which are less explored in literature. The authors propose using a series of non-heme iron(II) complexes supported by tetradentate and pentadentate aminopyridine ligands containing varying substituents to activate O₂ and generate iron-oxygen intermediates in the presence of electron and proton donors. Organic amines will be used as stoichiometric sacrificial electron donors and viologen salts as electron mediators. Upon visible light irradiation, the iron(II)-catalysts, photosensitizer, and electron mediator will activate O₂ and generate high-valent iron-oxygen intermediates for the oxidation of different organic substrates. Photocatalytic efficiency will be affected by different substituents on the ligands, photosensitizers, and irradiation wavelength.