Understanding the Light-driven Generation of Metallonitrenes for Unsensitized Nitrogen Atom Transfer Photocatalysis

• Applicants: Professorin Dr. Vera Krewald; Professor Dr. Biprajit Sarkar; Professor Dr. Sven Schneider; Professor Dr. Peter Vöhringer
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 404522842

This project proposes a joint synthetic, spectroscopic and computational approach to unravel the complex photophysics and photochemistry of the light-driven transformation of azide complexes to metallonitrene species, i.e. complexes with singly bonded, atomic nitrogen ligands with subvalent, N-centered biradical character (LnM–N:). For this purpose, octahedral, tervalent group 9 and square-planar, divalent group 10 azide complexes with electronic singlet ground states will be used as model platforms. These systems enable to separately probe in a rational way the roles of the energetics of relevant singlet and triplet excited states, the intersystem crossing, and the conformational dynamics by means of ultrafast pump-probe spectroscopy with UV-vis and mid-IR detection in combination with quantum chemical calculations. Electronic and structural predictors for the photochemical formation of metallonitrenes, as well as models for the (electronic) structures and reactivity of the photoproducts will be developed by experimental and computational methods. These will serve as guidelines for the development and mechanistic elucidation of photocatalytic nitrogen atom transfer protocols via metallonitrene key intermediates that lead to unprecedented C–H amination, C=C aziridination and C=C/C=N metathesis reactions.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2102: Light Controlled Reactivity of Metal Complexes
• International Connection: Austria
• Cooperation Partner: Professorin Dr. Leticia González