Nuclear Magnetic Resonance Spectroscopy

by Nelson, John H.

• ISBN13: 9780130334510
• ISBN10: 0130334510
• Edition: 1st
• Format: Paperback
• Copyright: 2002-07-08
• Publisher: Prentice Hall

Summary

This is the only how-to volume that investigates the spectroscopy of a variety of nuclides other thanH andC in depth. It contains extensive reference material and numerous problems, most of which include real spectra. It is written to provide users with the knowledge necessary to choose the most appropriate experiment to obtain the best quality spectra with the ability to fully interpret the data. The book covers basic theory of NMR spectroscopy, spectrum measurement, the chemical shift and examples for selected nuclei, symmetry and NMR spectroscopy, spin-spin coupling and NMR spin systems, typical magnitude of selected coupling constants, nuclear spin relaxation, the nuclear overhauser effect, editingC NMR spectra, two-dimensional NMR spectroscopy, dynamic NMR spectroscopy, lanthanide shift reagents (LSR), NMR of solids. For NMR spectroscopists and analytical chemists.

Table of Contents

Most chapters end with an Additional Reading section.
1. Basic Theory of NMR Spectroscopy.

Nuclear Spin. Interaction of Nuclear spins with Magnetic Fields. Precession and Larmour Frequency. Nuclear Energy Levels and Relaxation. The Rotating Frame of Reference. The Bloch Equations.

2. Measurement of the Spectrum-Instrumentation.

Fundamental Components of an NMR Spectrometer. The Magnet. The Transmitter Coil. The Receiver Coil. The Sample. Obtaining a Spectrum. Continuous-Wave Experiments. Fourier Transform Experiments. Detecting the Signal and Digitizing the Data. Processing the Signal. The Fourier Transformation Process. Double and Triple Resonance. Homonuclear Decoupling. Heteronuclear Decoupling. Pulse Sequences. Signal-to-Noise Ratio.

3. The Chemical Shift and Examples for Selected Nuclei.

General Considerations. Protein Chemical Shifts. Carbon Chemical Shifts. Boron Chemical Shifts. Nitrogen Chemical Shifts. Flourine Chemical Shifts. Phosphorous Chemical Shifts. Platinum Chemical Shifts.

4. Symmetry and NMR Spectroscopy.

Introduction. Spin-System Designation.

5. Spin-Spin Coupling and NMR Spin Systems.

General considerations. Quantum Mechanics and NMR Spectroscopy.

6. Typical Magnitude of Selected Coupling Constants.

General Considerations. Vicinal ( 3JHH) Couplings. Geminal ( 2JHH) Couplings. Long Range H—H Couplings.  1JCH Couplings.  2JCH and  3JCH Couplings.  nJCC Couplings.  nJNH and  3JNC Couplings.  nJFX Couplings.  nJPX Couplings.

7. Nuclear Spin Relaxation.

Introduction. Different Types of Relaxation. Microscopic Origin of Relaxation. Different Types of Relaxation Mechanisms. Experimental Behavior of Nuclear Relaxation. Experimental Measurement of Relaxation Times. The  13C Nucleus and Its Dominant Relaxation Mechanisms.

8. The Nuclear Overhauser Effect.

Introduction. Experimental Measurement.

9. Editing  13C NMR Spectra.

Introduction. Attached-Proton Test (APT). Distortionless Enhancement by Polarization Transfer (DEPT).

10. Two-Dimensional NMR Spectroscopy.

Introduction. The Basic Two-Dimensional NMR Experiment. Graphical Presentation of 2D NMR Spectra. Two-Dimensional I-Resolved Spectroscopy. Two-Dimensional Correlated Spectroscopy. Two-Dimensional Exchange Spectroscopy (NOESY and EXSY). The Two-dimensional INADEQUATE Experiment. HMQC and HMBC Spectra. Data Acquisition and Processing Parameters in 2D NMR Spectroscopy.

11. Dynamic NMR Spectroscopy.

Introduction. Determination of Exchange Rates. Coalescence Temperatures and Rate Constants at Coalescence. Complete Line-Shape Analysis. Activation Parameters. Equilibrium Thermodynamics. Examples of Dynamic Processes Studied by NMR Spectroscopy.

12. Lanthanide Shift Reagents (LSR).

Introduction. Theory of Shift Reagent-Substrate Interaction. Contact and Depolar Interactions. Dtermination of Molecular Geometry. Chiral Lanthanide-Shift Reagents. Practical Considerations.

13. NMR of Solids.

Introduction. Proton Dipolar Broadening. Chemical-Shift Anisotropy. Magic-Angles Spinning. Cross Polarization. Recapitualization. Crystallographic Equivalence, Chemical-Shift Equivalence, and Magnetic Equivalence in CP/MAS NMR Spectra. Molecular Motion in the Solid State.

14. Problems.

Problems.

Appendix A: Selected Values of Longitudinal Relaxation Times for Some Nuclei.
Index.

Excerpts

It is probably safe to say that NMR spectroscopy is the most broadly utilized spectroscopic technique presently available for obtaining detailed information on chemical systems at the molecular level. Although there are a number of excellent books on NMR spectroscopy, most of the textbooks focus on 1 H and 13 C NMR spectroscopy and discuss other nuclei only briefly or not at all. Because Fourier Transform (FT) spectrometers are now generally available in both academic and industrial settings, the synthetic chemist can, and often does, routinely investigate the spectroscopy of a variety of nuclides. Moreover, some of the fundamental principles are best illustrated by considering the properties and spectra of nuclei other than 1 H and 13 C.This book was written as a textbook for senior undergraduate and graduate students who need a reasonably thorough discussion of the subject at an introductory level. It contains a fair amount of chemical-shift and coupling-constant data for seven of the more widely studied nuclides ( 1 H, 11 B, 13 C, 15 N, 19 F, 31 P, and 195 Pt), but is not a compendium of such data. References to compendia are given in the appropriate places in the text. The book is largely empirical, but the theoretical basis for most of the more important aspects is presented. I have attempted to explain each of the various experiments at a level such that the reader can ascertain which among several alternatives would be the best experiment to use. The practitioner should always ask, "What information do I want to obtain?" Then the best, and hopefully easiest, experiments can be chosen to provide that information most expeditiously.Since students often learn this type of material best by solving problems, a large number of practice problems have been included. The majority of them involve actual spectra. The problems have been chosen to represent the concepts discussed in the book, but, of course, are biased by my own interests. An answer book containing detailed solutions is available.Some figures have been taken from the literature, and acknowledgments are given in the appropriate captions. I wish to thank Dr. George A. Gray of Varian Associates, Mr. Lewis W. Cary and Dr. Stephan E. Boiadjiev of the University of Nevada, and Professor Roderick E. Wasylishen of Dalhousie University for several of the spectra reproduced herein. I am also grateful to the many students at UNR who have endured the various forms of this book in my classes. I appreciate their comments, their insightful and probing questions, and their encouragement to complete the book.