Role of hyperconjugation if secondary BETA-deuterium isotope effects
The effect of hyperconjugation of the magnitudes of secondary BETA-deuterium isotope effects has been investigated by ion cyclotron resonance spectroscopy and a b initio molecular orbital theory. Isotope effects measured for ion-molecule equilibria involving formation either of a nonbonded pair of electrons or of a vacant orbital adjacent to a methyl probe have been compared to theoretical calculations which have been restricted to consideration of changes in CH stretching force constants alone. Although this simple theoretical model successfully mirrors the observed BETA effects in the former systems in which the methyl group acts to accept excess electron density, it fails to properly account for the observed effects in those systems where the methyl probe is adjacent to an electron-deficient center. (2 tables)
- Research Organization:
- Univ. of California, Irvine
- OSTI ID:
- 5619632
- Journal Information:
- J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 101:19; ISSN JACSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400202* -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALKYL RADICALS
BETA PARTICLES
CHARGED PARTICLES
DEUTERIUM
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
HYDROGEN ISOTOPES
ION CYCLOTRON RESONANCE SPECTROSCOPY
ION SPECTROSCOPY
ISOTOPE EFFECTS
ISOTOPES
LEPTONS
LIGHT NUCLEI
METHYL RADICALS
MOLECULAR ORBITAL METHOD
NUCLEI
ODD-ODD NUCLEI
RADICALS
SPECTROSCOPY
STABLE ISOTOPES