High Precision Measurement of Isotope Effects on Noncovalent Host-Guest Interactions

Isotope effects (IEs) are a powerful tool for examining the reactivity of, and interactions between, molecules. Recently, secondary IEs have been used to probe the nature of noncovalent interactions between guest and host molecules in supramolecular systems. While these studies can provide valuable...

Full description

Saved in:
Bibliographic Details
Published in:Journal of the American Chemical Society 2009-06, Vol.132
Main Authors: Mugridge, Jeffrey S., Bergman, Robert G., Raymond, Kenneth N.
Format: Article
Language:English
Subjects:
ACCURACY
AMINES
CARBOXYLIC ACIDS
ISOTOPE EFFECTS
PH VALUE
PHENOLS
PROBES
TITRATION
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Isotope effects (IEs) are a powerful tool for examining the reactivity of, and interactions between, molecules. Recently, secondary IEs have been used to probe the nature of noncovalent interactions between guest and host molecules in supramolecular systems. While these studies can provide valuable insight into the specific interactions governing guest recognition and binding properties, IEs on noncovalent interactions are often very small and difficult to measure precisely. The Perrin group has developed an NMR titration method capable of determining ratios of equilibrium constants with remarkable precision. They have used this technique to study small, secondary equilibrium isotope effects (EIEs) on the acidity of carboxylic acids and phenols and on the basicity of amines, measuring differences down to thousandths of a pK{sub a} unit. It occurred to us that this titration method can in principle measure relative equilibrium constants for any process which is fast on the NMR timescale and for which the species under comparison are distinguishable by NMR. Here we report the application of this method to measure very small EIEs on noncovalent host-guest interactions in a supramolecular system.
ISSN:0002-7863
1520-5126