6393-09-5Relevant articles and documents
Evidence of hydrogen migration in an alkylphenyldiazirine excited state
Zhang, Yunlong,Kubicki, Jacek,Platz, Matthew S.
supporting information; experimental part, p. 3182 - 3184 (2010/09/16)
(Figure Presented) Ultrafast photolysis (350 nm) of alkylphenyldiazirines promotes the diazirine to the S1 excited state. Solvent and substituent effects on the excited state lifetimes indicate that the S 1 state is highly polarized and undergoes a [1,2]-H shift in concert with nitrogen extrusion in cyclohexane.
Direct Spectroscopic Observation of Intramolecular Hydrogen Shifts in Carbenes
McMahon, Robert J.,Chapman, Orville L.
, p. 683 - 692 (2007/10/02)
Triplet o-tolylmethylene (13a) decays thermally to singlet o-xylylene (14a) in an argon matrix at temperatures as low as 4.6 K.The thermal, intramolecular -hydrogen shift has been observed directly by IR and UV spectroscopy.The carbene disappearance kinetics follow the standard (time)1/2 dependence, due to multiple reaction sites in the matrix.The small temperature dependence and non-Arrhenius behavior of the rate implicate a tunneling mechanism.In contrast, triplet 1-phenylethylidene (17a) is thermally stable in argon or xenon matrices at 10 K.Warming 17a to 65 K in a xenon matrix produces styrene (18a).The intramolecular -hydrogen shift has been observed directly by IR spectroscopy.The carbene disappearance kinetics show apparent first-order behavior.We estimate an upper limit of ca. 4.7 kcal/mol for the singlet-triplet energy gap in 17a.
