A Theoretical Ivnestigation of a-Carbon Kinetic Isotope Effects and Their Relationship to the Transition-State Structure of SN2 Reactions
2005 (English)In: J. Org. Chem., no 70, 4022-4027 p.Article in journal (Refereed) Published
The transition structures and a-carbon 12C/13C kinetic isotope for 22 SN2 reactions between methyl chloride and a wide variety of nucleophiles have been calculated using the B1LYP/aug-cc-pVDZ level of theory. Anionic, neutral, and radical anion nucleophiles were used to give a wide range of SN2 transition states so the relationship between the magnitude of the a-carbon kinetic isotope effect and trasition-state structure could be determined. The results suggest that the a-carbon 12C/13C kinetic isotope effects for SN2 reactions will be large (near the experimental maximum) and that the curve relating the magnitude of the KIE to the percent transfer of the a-carbon from the nucleophile to the leaving group in the transition state has a broad maximum. This means very similar KIEs will be found for early, symmetric, and late transition states and that one cannot use the magnitude of these KIEs to estimate transition-state structure.
Place, publisher, year, edition, pages
2005. no 70, 4022-4027 p.
IdentifiersURN: urn:nbn:se:uu:diva-83889DOI: doi:10.1021/jo047987yOAI: oai:DiVA.org:uu-83889DiVA: diva2:111797