High Resolution NMR

Preface to Second Edition

Preface to First Edition

Acknowledgments


1. Introduction


1.1 Historical


1.2 High Resolution NMR


2. The Theory of NMR


2.1 Nuclear Spin and Magnetic Moment


2.2 Classical Mechanical Description of NMR


2.3 Quantum Mechanical Description of NMR


2.4 Effect of the Boltzmann Distribution


2.5 Spin—Lattice Relaxation


2.6 Line Widths


2.7 Saturation


2.8 Macroscopic Magnetization


2.9 The Bloch Equations: Nuclear Induction


2.10 The Rotating Frame of Reference


2.11 Adiabatic Passage; Ringing

Problems


3. Instrumentation and Techniques


3.1 Basic NMR Apparatus


3.2 Requirements for High Resolution NMR


3.3 Modulation and Phase Sensitive Detection


3.4 Field/Frequency Control


3.5 Signal/Noise and Size of Sample


3.6 Fourier Transform Methods


3.7 Intensity Measurements


3.8 References


3.9 Magnetic Susceptibility Measurements


3.10 Frequency Calibration


3.11 Control of Sample Temperature


3.12 Useful Solvents


3.13 Sampling Techniques


3.14 Micro Techniques

Problems


4. Chemical Shifts


4.1 The Origin of Chemical Shifts


4.2 Reference Compounds


4.3 Chemical Shift Scales


4.4 Magnetic Susceptibility Correction


4.5 Empirical Correlations of Chemical Shifts


4.6 Theory of Chemical Shifts


4.7 Effect of Electron Density


4.8 Magnetic Anisotropy and Chemical Shifts


4.9 Ring Currents


4.10 Nuclei Other Than Hydrogen


4.11 Carbon-13


4.12 Tabulations of Chemical Shifts and Spectra


4.13 Empirical Estimation of Chemical Shifts


4.14 Isotope Effects on Chemical Shifts


4.15 Paramagnetic Species


4.16 Lanthanide Shift Reagents

Problems


5. Electron-Coupled Spin—Spin Interactions


5.1 Origin of Spin—Spin Coupling


5.2 Coupling between Groups of Equivalent Nuclei


5.3 First-Order Analysis


5.4 Signs of Coupling Constants


5.5 Theory of Spin—Spin Coupling


5.6 Some Observed Coupling Constants


5.7 Correlation of Coupling Constants with Other Physical Properties


5.8 Tabulations of Coupling Constants

Problems


6. The Use of NMR in Structure Elucidation


6.1 A Systematic Approach to the Interpretation of NMR Spectra


6.2 Some Features of Carbon-13 Spectra


6.3 Structure Elucidation of Polymers

Problems


7. Analysis of Complex Spectra


7.1 Notation


7.2 Energy Levels and Transitions in an AX System


7.3 Quantum Mechanical Formalism


7.4 Nuclear Spin Basis Functions


7.5 The Spin Hamiltonian


7.6 The Two-Spin System without Coupling


7.7 Factoring the Secular Equation


7.8 Two Coupled Spins


7.9 Selection Rules and Intensities


7.10 The AB Spectrum


7.11 Spectral Contributions from Equivalent Nuclei


7.12 Symmetry of Wave Functions


7.13 Summary of Rules for Calculating Spectra


7.14 The Three-Spin System: ABC


7.15 The A2B System


7.16 The A3B System; Subspectral Analysis


7.17 The ABX System


7.18 Analysis of an ABX Spectrum


7.19 Relative Signs of JAX and JBx in an ABX Spectrum


7.20 ABX Patterns; Deceptively Simple Spectra


7.21 “Virtual Coupling”


7.22 The AB'BB' and AA'XX' Systems


7.23 Other Complex Spectra


7.24 Aids in the Analysis of Complex Spectra


7.25 Carbon-13 Satellites


7.26 Effects of Molecular Asymmetry


7.27 Polymer Configuration


7.28 Use of Liquid Crystals as Solvents

Problems


8. Relaxation


8.1 Molecular Motions and Processes for Relaxation in Liquids


8.2 Nuclear Magnetic Dipole Interactions


8.3 Relaxation via Chemical Shift Anisotropy


8.4 Spin—Rotation Relaxation


8.5 Electric Quadrupole Relaxation


8.6 Scalar Relaxation


8.7 Relaxation by Paramagnetic Substances


8.8 Some Chemical Applications


8.9 Measurement of Relaxation Times

Problems


9. Theory and Application of Double Resonance


9.1 Notation and Terminology


9.2 Experimental Techniques


9.3 Theory of Double Resonance


9.4 The Nuclear Overhauser Effect


9.5 Structure Elucidation


9.6 Location of “Hidden” Lines


9.7 Determination of Chemical Shifts


9.8 Relative Signs of Coupling Constants


9.9 Determination of Energy Level Arrangements


9.10 “High Resolution” Spectra in Solids

Problems


10. Pulse Fourier Transform Methods


10.1 RF Pulses and the Free Induction Decay


10.2 Fourier Transformation of the FID


10.3 Instrumental Requirements


10.4 Data Processing in the Computer


10.5 Sensitivity Enhancement by Time Averaging


10.6 Measurement of Relaxation Times


10.7 Two-Dimensional FT-NMR

Problems


11. Exchange Processes: Dynamic NMR


11.1 Spectra of Exchanging Systems


11.2 Theory of Chemical Exchange


11.3 Collapse of Spin Multiplets


11.4 More Complete Theories of Exchange


11.5 Double Resonance and Pulse Techniques


11.6 CIDNP

Problems


12. Solvent Effects and Hydrogen Bonding


12.1 Medium Effects on Chemical Shifts


12.2 Solvent Effects on Coupling Constants


12.3 Solvent Effects on Relaxation and Exchange Rates


12.4 Hydrogen Bonding

Problems


13. Use of NMR in Quantitative Analysis


13.1 Advantages of NMR in Quantitative Analysis


13.2 Drawbacks and Problems in the Use of NMR in Quantitative Analysis


13.3 Some Analytical Uses of NMR


14. Contemporary Developments in NMR


14.1 Solids


14.2 Multinuclear NMR


14.3 Biochemical Studies


14.4 NMR Imaging

References

Appendix A General NMR References

Appendix B Nuclear Spins, Magnetic Moments, and Resonance Frequencies

Appendix C Proton and Carbon-13 NMR Spectra of “Unknowns”

Appendix D Answers to Selected Problems

Index