Quantum Statistical Corrections to Dynamic Nuclear Magnetic Resonance
- 1 January 1999
- journal article
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 283 (5398) , 61-65
- https://doi.org/10.1126/science.283.5398.61
Abstract
A quantum statistical treatment of the chemical exchange between molecular eigenstates or conformations revealed previously unsuspected dynamic terms in the spin Hamiltonian operator that describes fast exchange. These terms resulted from the effect of nuclear spin on rotational and vibrational relaxation. With the traditional theory, an interpretation of new carbon-13 nuclear magnetic resonance measurements of the chemical shift of methylcyclohexane in solution showed fast-exchange equilibrium constants that were inconsistent with the slow-exchange free-energy difference and were spread over a range of 30 percent for the various carbon-13 positions. Modeling of the new terms indicated that they have the correct magnitude and temperature dependence to reconcile these inconsistencies.Keywords
This publication has 15 references indexed in Scilit:
- NMR Motional Averaging in the Isotopically Perturbed Cope RearrangementJournal of the American Chemical Society, 1998
- Reexamination of Motional Averaging in Magnetic ResonanceJournal of Magnetic Resonance, Series A, 1994
- Traditional averaging of NMR parameters in the fast exchange limit is valid!Chemical Physics Letters, 1993
- Complete 13C NMR spectra of the axial forms of methyl‐, ethyl‐ and isopropylcyclohexaneMagnetic Resonance in Chemistry, 1987
- The Kinetic and Mechanistic Evaluation of NMR Spectra. New analytical methods (18)Angewandte Chemie International Edition in English, 1980
- NMR dynamic frequency shifts and the quadrupolar interactionThe Journal of Chemical Physics, 1979
- Problems in Theory and Analysis of Dynamic Nuclear Magnetic Resonance SpectraPublished by Elsevier ,1978
- Calibration of methanol nuclear magnetic resonance thermometer at low temperatureAnalytical Chemistry, 1970
- Chapter 4 The calculation of line shapes by density matrix methodsProgress in Nuclear Magnetic Resonance Spectroscopy, 1967
- Relaxation Effects in Nuclear Magnetic Resonance AbsorptionPhysical Review B, 1948