Ultrafast Vibrational Spectroscopy of Photochemical High-Valent Iron Formation

The light-induced formation of a super-oxidized iron complex via dinitrogen cleavage from a ferric azido-iron precursor is measured by femtosecond UV/Vis-pump mid-infrared-probe spectroscopy. The spectro-temporal evolution is indicative of two photooxidation pathways: (i) a prompt N2-dissociation directly on the optically prepared excited state of the precursor and (ii) a delayed N2-elimination from the vibrationally hot ground state.