A New Interpretation of Chlorine Leaving Group Kinetic Isotope Effects; A Theoretical Approach
2004 (Swedish)In: J. Org. Chem., Vol. 69, 4900-4905 p.Article in journal (Refereed) Published
The chlorine leaving group kinetic isotope effects (KIEs) for the SN2 reactions between methyl chloride and a wide range of anionic, neutral, and radical anion nucleophiles were calculated in the gas phase and, in several cases, using a continuum solvent model. In contrast to the expected linear dependence of the chlorine KIEs on the Ca-CI bond order in the transition state, the KIEs fell in a very small range (1.0056-1.0091), even though the Ca-CI transition state bond orders varied widely from approximately 0.32 to 0.78, a range from reactant-like to very product-like. This renders chlorine KIEs, and possibly other leaving-group KIEs, less useful for studies of reaction mechanisms than commonly assumed. A partial explanation for this unexpected relationship between the Ca-CI transition state bond order and the magnitude of the chlorine KIE is presented.
Place, publisher, year, edition, pages
2004. Vol. 69, 4900-4905 p.
IdentifiersURN: urn:nbn:se:uu:diva-69912OAI: oai:DiVA.org:uu-69912DiVA: diva2:97823