NMR Spectroscopy Using Liquid Crystal Solvents

PrefaceAcknowledgmentsChapter 1. Liquid Crystals 1.1 Introduction 1.2 Classification of Mesophases 1.2.1. The Nematic Mesophase 1.2.2. The Cholesteric Mesophase 1.2.3. Smectic Mesophases 1.3 Effect of Magnetic Fields on Liquid Crystals 1.4 Quantitative Description of Liquid Crystals Ordered by a Magnetic Field 1.5 Nuclear Resonance Spectra of Solutes Dissolved in Liquid Crystals References Chapter 2. The Nuclear Spin Hamiltonian for Partially Oriented Molecules 2.1 Introduction 2.2 The Zeeman Term 2.3 Indirect Spin-Spin Coupling 2.4 Dipolar Coupling 2.5 Nuclear Quadrupole Interaction 2.6 Total Anisotropic Spin-Spin Coupling ReferencesChapter 3. Analysis of NMR Spectra of Partially Oriented Molecules 3.1 Introduction 3.2 Magnetic Equivalence 3.3 Classification of Spin Systems 3.4 Spin Systems Having Analytical Solutions 3.4.1. An 3.4.2. AB 3.4.3. AB2 3.4.4. AB3 3.4.5. AA'A''A''' 3.4.6. AA'BB' 3.4.7. AA'XX' 3.4.8. AA'A''A'''A'''' 3.4.9. A3A3' 3.4.10. AA'A''A'''A''''A''''' 3.5 Analysis of Spin Systems Using the X Approximation 3.6 Computer Analysis 3.7 Multiple Solutions 3.8 Errors on Parameters Determined From Computer Analysis ReferencesChapter 4. Determination of the Structure of Rigid Molecules 4.1 Introduction 4.2 Relationship between Dipolar Coupling Constants and Structure 4.3 Vibrational Averaging 4.3.1. Introduction 4.3.2. The Effective Structure 4.4 Example of Rz Structures Determined by NMR 4.4.1. Benzene 4.4.2. Benzene-dl 4.4.3. Pyridine-l5N 4.4.4. Fluorinated Aromatic Compounds 4.4.5. p-Cyclopentadienyl Compounds 4.4.6. Cyclobutadiene Iron Tricarbonyl 4.4.7. Cyclopropane 4.4.8. Cyclopentadiene 4.4.9. p-Allyl Rhenium Tetracarbonyl 4.5 Effect of the Liquid Crystal Phase on the Structure of Solutes 4.5.1. Tetrahedral Molecules 4.5.2. Acetylene 4.5.3. Norbornadiene 4.5.4. Methyl Fluoride 4.5.5. Difluoroethylenes 4.6 Molecular Complexes 4.7 Computational Methods 4.8 Survey of Results ReferencesChapter 5. Studies of Internal Motion 5.1 Introduction 5.2 Averaging of Dipolar Couplings 5.2.1. Rotation between Symmetry Related Configurations 5.2.2. Rotation or Exchange between Structures with Symmetry Relationships 5.2.3. Calculation of Rotational Probabilities 5.3. Determination of Barrier Heights 5.3.1. Dependent Internal Rotos 5.4 Comparison Between Structures Determined by NMR and Microwave Spectroscopy for a Molecule with Internal Rotation 5.5 Averaging of Dipolar Couplings Over Ring Puckering Motion 5.6 Valence Isomerisation 5.7 Survey of Results ReferencesChapter 6. NMR Spectra From Quadrupolar Nuclei 6.1 Introduction 6.2 Spectra of Nuclei With I=l 6.2.1. A Single Nucleus 6.2.2. A Single Deuterium Coupled to other Nuclei 6.2.3. Two Deuterium Nuclei 6.2.4. Three Nuclei A3 with Symmetry 6.3 Relationship between qzz and Components of q in a Molecule-Fixed Axis System 6.4 Determination of Quadrupole Coupling Constants 6.4.1. Introduction 6.4.2. Examples of Determination of Quadrupole Coupling Constants 6.5 Survey of Results 6.5.1. Deuterium 6.5.2. Nitrogen 6.6 Determination of Orientation From Quadrupole Coupling Constants 6.6.1. Solute Orientation 6.6.2. Orientation of Pure Liquid Crystals ReferencesChapter 7. Anisotropy in Nuclear Spin-Spin Coupling 7.1 Introduction 7.2 Theory of Spin-Spin Coupling 7.2.1. The Hamiltonian 7.2.2. Methods of Calculation 7.2.3. Expressions for Jnn, in the Sum Over States Method 7.