1. Generation and Kinetic Studies of High-Valent Metal-Oxo Intermediates
Rui Zhang, Department of Chemistry, Western Kentucky University, Bowling Green, KY 42101
We have successfully developed a new preparation of trans-dioxoruthenium(VI) porphyrin complexes by an extremely easy photochemical approach. We have demonstrated the generality of the methodology in sterically encumbered and unencumbered systems under same conditions, bypassing the limitation observed in chemical methods. We have also demonstrated that the ruthenium(IV)--oxo bisporphyrins catalyzed efficient aerobic oxidation of alkenes and activated hydrocarbons using visible light and atmospheric oxygen. The observed photocatalytic oxidation is ascribed to a photo-disproportionation mechanism to afford a putative porphyrin-ruthenium(V)-oxo species that can be directly observed and kinetically studied by laser flash photolysis methods.