Time-Resolved Observation of Sequential Bond Cleavage in a Gas-Phase Azoalkane

Article abstract of DOI:10.1021/ja00285a009

The gas-phase photodissociation of an unsymmetrical azoalkane, 3-(methylazo)-3-methyl-1-butene, was studied with time-resolved coherent anti-Stokes Raman spectroscopy (CARS) to probe for product formation.Appearance kinetics were measured for all three primary photoproducts.The results indicate a two-step dissociation mechanism in which the 1,1-dimethylallyl fragment is formed within 2 ns of excitation, whereas the methyl radical and N2 are formed through decay of reaction intermediate having a lifetime of 12 +/- 2 ns.These findings mark the first direct demonstration of a stepwise homolysis mechanism for an azoalkane.