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The Cope Rearrangement of 1,5-Dimethylsemibullvalene-2(4)-d1: Experimental Evidence for Heavy-Atom Tunneling.

Authors :
Schleif, Tim
Mieres ‐ Perez, Joel
Henkel, Stefan
Ertelt, Melanie
Borden, Weston Thatcher
Sander, Wolfram
Source :
Angewandte Chemie. Aug2017, Vol. 129 Issue 36, p10886-10889. 4p.
Publication Year :
2017

Abstract

As an experimental test of the theoretical prediction that heavy-atom tunneling is involved in the degenerate Cope rearrangement of semibullvalenes at cryogenic temperatures, monodeuterated 1,5-dimethylsemibullvalene isotopomers were prepared and investigated by IR spectroscopy using the matrix isolation technique. As predicted, the less thermodynamically stable isotopomer rearranges at cryogenic temperatures in the dark to the more stable one, while broadband IR irradiation above 2000 cm−1 results in an equilibration of the isotopomeric ratio. Since this reaction proceeds with a rate constant in the order of 10−4 s−1 despite an experimental barrier of Ea=4.8 kcal mol−1 and with only a shallow temperature dependence, the results are interpreted in terms of heavy-atom tunneling. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00448249
Volume :
129
Issue :
36
Database :
Academic Search Index
Journal :
Angewandte Chemie
Publication Type :
Academic Journal
Accession number :
124787503
Full Text :
https://doi.org/10.1002/ange.201704787