Isotope effects on isotope effects. Failure of the rule of geometric mean as evidence for tunneling

Journal Article · Wed Jun 08 04:00:00 EDT 1988 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00220a084· OSTI ID:7200377

Amin, M; Price, R C; Saunders, Jr, W H

The authors showed in earlier work that secondary ..beta..-tritium isotope effects in eliminations from 2-arylethyl derivatives are often larger than expected on the basis of rehybridization of the C-H(T) bond from sp/sup 3/ to sp/sup 2/ as the system progresses along the reaction coordinate. They suggested that a contribution of tunneling to the secondary isotope effect could be responsible for this discrepancy and presented calculations showing that a significant tunnel correction results when the bending motions of the non-transferred hydrogen are coupled with the stretching motion of the transferred hydrogen. The calculations also predict that the tunnel correction to the secondary tritium isotope effect should be diminished when the transferred atom is deuterium rather than protium. They report here experimental evidence that this is indeed the case.

• Research Organization: Univ. of Rochester, NY (USA)
• OSTI ID: 7200377
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 110:12; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ALKOXY RADICALS
AMMONIUM COMPOUNDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
ELECTRONIC STRUCTURE
ETHOXY RADICALS
EXPERIMENTAL DATA
HYDROGEN ISOTOPES
INFORMATION
ISOTOPE EFFECTS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
RADICALS
RADIOISOTOPES
REACTION KINETICS
TRITIUM
TRITIUM COMPOUNDS
TUNNEL EFFECT
YEARS LIVING RADIOISOTOPES