Secondary deuterium kinetic isotope effects on the isomerization of the trimethylene diradical to cyclopropane
- Syracuse Univ., NY (United States)
- Univ. of Georgia, Athens, GA (United States)
The trimethylene diradical (1-d{sub 0}) has long been considered a possible or even a likely short-lived reactive intermediate. The precise character of the trimethylene intermediate is of course not revealed unambiguously through the agreement between calculated relative lifetimes and measured lifetimes shown here. The local energetic minimum in the many-dimensional potential energy surface for the trimethylene intermediate is quite shallow, and the diradical may exist in a variety of conformational forms characterized by different C-C-C bond angles and H-C-C-H dihedral angles without any substantial variations in energy. For such a molecular entity, nearly a `twixtyl`, `a molecule or a range of molecular conformations` having no minimum on a potential energy surface but `which operationally behaves as a true intermediate`, isomerization rates and lifetimes may be dictated more by the requirement that various vibrational modes must attain appropriate phase relationships with one another rather than by any all-important activation energy criterion. 26 refs., 3 tabs.
- OSTI ID:
- 420701
- Journal Information:
- Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 44 Vol. 118; ISSN JACSAT; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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