35745-45-0Relevant academic research and scientific papers
Rearrangements of the Isomeric Tolylmethylenes
Chapman, Orville L.,Johnson, Jeffery W.,Mahon, Robert J. Mc,West, Paul R.
, p. 501 - 509 (2007/10/02)
We present evidence for a mechanism in which the isomeric tolylmethylenes interconvert via methylcycloheptatetraene intermediates.Photolysis (>470 nm) of diazo compounds 1-4, matrix isolated in argon at 10 K, generates triplet tolylmethylenes 8-11.Photoly
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.
