An inverse reactivity-selectivity relationship. Kinetic nitrogen isotope effects on methyl transfer to pyridines

Journal Article · Wed Oct 20 00:00:00 EDT 1982 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00385a062· OSTI ID:6447467

Kurz, J L ^[1]; Seif El-Nasr, M M

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1. Washington Univ., St. Louis, MO

This paper reports that values of the /sup 14/N//sup 15/N rate constant ratio for methyl transfer to alkyl-substituted pyridines decrease (become more inverse) as CH/sub 3/X becomes more reactive and may also decrease as the pyridine becomes more reactive. These changes in K/sub 14//K/sub 15/ demonstrate increasing selectivity for /sup 15/N in preference to /sup 14/N as reactivity increases and thus are in violation of the reactivity-selectivity principle. However, these observed changes in K/sub 14//K/sub 15/ are consistent with a very recent prediction that such ''anti-Hammond'' effects should result from changes in quantum mechanical mixing of configurations in the transition state and should dominate the more familiar effects of structural perturbations of the free energy surface.

• OSTI ID: 6447467
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 104:21; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400302* -- Organic Chemistry-- Isotope Effects-- (-1987)
AZINES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
HETEROCYCLIC COMPOUNDS
ISOTOPE EFFECTS
ISOTOPES
KINETICS
LIGHT NUCLEI
METHYLATION
NITROGEN 14
NITROGEN 15
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
REACTION KINETICS
STABLE ISOTOPES