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Updated: Jul 6, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Enthalpy versus entropy in chlorocarbene/alkene addition reactions
Robert A Moss1, Lei Wang, Min Zhang
1Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, New Brunswick, New Jersey 08903, USA. moss@rutchem.rutgers.edu
Abstract:
We report the first measured activation parameters for the additions of CCl2 and CClF to simple alkenes and demonstrate the existence of enthalpic barriers for CCl2 additions to cyclohexene and 1-hexene. With these two alkenes, additions of PhCCl are "dominated" by entropic contributions to deltaG++ and additions of CCl2 display comparable contributions of deltaH++ and deltaS++, while CClF additions feature dominant enthalpic contributions to deltaG++. Entropic factors, however, control the additions of all three carbenes to the highly reactive alkene, tetramethylethylene. Parallel computational studies are also reported.
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