Selective C–H bond functionalization with light-driven P450 biocatalysts

The unique photochemical properties of Ru(II)-diimine photosensitizers have enabled light-induced electron transfers in hybrid P450 heme domain enzymes. Rapid quenching of the excited state by soluble molecules generates either a highly oxidative or reductive species depending on the nature of the quencher. Under flash quench oxidative conditions, the heme cofactor of the P450 BM3 enzyme is oxidized to a high-valent ferryl species. Meanwhile, a photogenerated reductive species is able to deliver the necessary electrons to P450 heme active sites and sustain photocatalytic activity in the selective hydroxylation of substrate C–H bonds.