Ultrafast Dynamics of Photochemical Nitrile Imine Formation

The chemical reactivity of nitrile imines is great utility in organic synthesis with applications rapidly expanding into the materials and life sciences. Yet, our understanding electronic molecular structures remains incomplete elementary mechanism their photoinduced generation entirely unknown. Here, femtosecond infrared spectroscopy after 266 nm-excitation 2,5-diphenyltetrazole has been carried out to temporally resolve formation structural relaxation dynamics nascent diphenylnitrile imine liquid solution under ambient conditions. infrared-spectroscopic evolution interpreted by an initial sequence intersystem crossings within 250 fs followed cleavage N2 a structurally relaxed on adiabatic ground-state singlet surface few tens picoseconds. spectrum supports notion “floppy” molecule whose equilibrium character ranges from fully propargylic allenic room temperature solution.