Direct observation of 1,2-hydrogen migration in the excited states of alkyl diazo esters by ultrafast time resolved IR spectroscopy

G. Burdzinski (1) , Y. Zhang (2) , P. Selvaraj (2) , M. Sliwa (3) , M.S. Platz (2)

1 Quantum Electronics Laboratory
2 Department of Chemistry
3 LASIRE - Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516

The mechanism of 1,2-H migration process in photoexcited alkyl diazo esters was studied by femtosecond IR transient absorption spectroscopy and theoretical calculations. Two possible processes are discussed: rearrangement in the diazo excited state (RIES) and the intermediacy of singlet carbene species. In chloroform solvent ulrafast IR data show a subpicosecond rise of alkene species indicating the occurrence of the RIES process. Failure in carbene species detection is explained by their absence or very low quantum yield of formation.

Domaines: Chimie théorique et/ou physique

G. Burdzinski, Y. Zhang, P. Selvaraj, M. Sliwa, M.S. Platz. Direct observation of 1,2-hydrogen migration in the excited states of alkyl diazo esters by ultrafast time resolved IR spectroscopy. Journal of the American Chemical Society, 2010, 132, pp.2126 - 2127. ⟨10.1021/ja909687g⟩. ⟨hal-00514776⟩