MULTINUCLEAR NMR. EDITED BY JOAN MASON The Open University Milton Keynes, Buckinghamshire, England PLENUM PRESS NEW YORK AND LONDON

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1 MULTINUCLEAR NMR EDITED BY JOAN MASON The Open University Milton Keynes, Buckinghamshire, England PLENUM PRESS NEW YORK AND LONDON

2 CONTENTS Chapter 1 Introduction 1 Joan Mason Chapter 2 The Parameters of NMR Spectroscopy Cynthia J. Jameson and Joan Mason 1. Nuclear Properties of the Elements and the Resonance Condition 3 2. The Nucleus in a Chemical Environment The Chemical Shift and the Shielding Tensor Dipolar (D) Coupling Indirect Spin-Spin (/) Coupling Electric Quadrupole Coupling Relaxation The Larmor Precession and the Bloch Equations The Fourier Transform Technique Multipulse and Multiple Resonance Techniques Double Resonance Experiments Techniques for Signal Enhancement Techniques in Aid of Spectral Analysis and Assignment Oriented Systems High Resolution NMR Techniques for Solids Experimental Determination of Tensor Components of <x, J, D, and q The NMR Time Scale Physical Effects on the NMR Parameters Medium and Temperature Effects Isotope Effects Effects of Paramagnetic Substances 44 References 46 Chapter 3 The Chemical Shift Cynthia J. Jameson and Joan Mason 1. Nuclear Magnetic Shielding and the Chemical Shift The Absolute Shielding Te'nsor The Diamagnetic and Paramagnetic Contributions to Shielding The Relationship between a p and the Nuclear Spin-Rotation Constant.. 53 xi

3 XU CONTENTS 1.4. Molecular Symmetry and Nuclear Magnetic Shielding Absolute Shielding Scales Experimental Methods of Determining the Shielding Anisotropy Theoretical Description Computational Schemes Relativistic Effects Approximate Calculations and Models Patterns of Chemical Shifts Chemical Shift Ranges of the Nuclei Scaling of Chemical Shifts General Factors in the Shielding of Main-Group and Transition Metal Nuclei Dependence of Nuclear Shielding on Charge Density, Oxidation State, and Substituent Electronegativity Correlations with Electronic Excitation and Ionization Energies Substituent Effects Correlations of Chemical Shifts with Other Molecular Properties Nuclear Quadrupole Coupling Constants Van Vleck Paramagnetism, and the Electronic' g Tensor Spin-Spin Coupling Constants and Relaxation Times Bond Properties Shifts in Paramagnetic Systems Effects of Intermolecular Interactions and Intramolecular* Dynamics Medium Effects Rovibrational Averaging and Isotope Effects Dynamic Processes: Fluxional, Conformational and Exchange Equilibria 82 References 83 Chapter 4 Spin-Spin Coupling Cynthia J. Jameson 1. General Considerations Mechanisms of Spin-Spin Coupling Anisotropy of the Spin-Spin Coupling Methods of Determining Signs of Coupling Constants Empirical Patterns of Coupling Constants Signs and General Magnitudes of "K(XY) Structural Factors Affecting l K Structural Factors Affecting the Sign and Magnitude of 2 K Structural Factors Affecting the Sign and Magnitude of 3 K Effects of Intermolecular Interactions and Intramolecular Dynamics on Spin- Spin Coupling Averaging via Rotameric Equilibria and Intramolecular Rearrangement Isotope Effects Chemical Exchange and Medium Effects Theoretical Description Computational Schemes 113

4 CONTENTS Xlll 4.2. Relative Importance of the Fermi Contact, Spin Dipolar and Orbital Terms Relativistic Effects Approximate Calculations and Models 118 References 123 Chapter 5 Relaxation and Related Time-Dependent Processes Oliver Howarth 1. Importance Definitions Macroscopic Definition of 7\ and T 2 : Bloch Equations Microscopic Interpretation Nuclear Overhauser Enhancement Relaxation in the Rotating Frame: T lp Microscopic Theory Spin-Lattice Relaxation Spin-Spin Relaxation Dependence of Spectral Density upon Frequency The Static Part V More Complete Treatments Specific Mechanisms, Dipole-Dipole Relaxation Scalar Interactions Shielding Anisotropy Spin-Rotation Interactions Electric Quadrupole Interactions Methods of Measurement \ Measurements Nuclear Overhauser Enhancement Measurements T 2 Measurement, and Other Uses of Spin Echoes Line Broadening Due to Chemical Exchange Ti in the Presence of Chemical Exchange, Paramagnetic Interactions Kinetics Paramagnetic Contributions to T t and T Two-Dimensional NMR Shift-Correlation Experiments /-Resolved Two-Dimensional Spectroscopy 167 References 168 Chapter 6 Hydrogen and Its Isotopes: Hydrogen, Deuterium, and Tritium J. W. Akitt 1. Introduction Experimental Techniques 172

5 XIV CONTENTS 3. Hydrogen or the Proton, or Protium Strong or Weak Hydrogen Bonds Ionic Solvation Chemical Shifts of Adducts Hydrogen on Carbon Hydride Protons Dynamic Processes ' Deuterium Deuterium NMR in Isotropie Liquids Deuterium NMR of Liquid Crystalline Phases Deuterium NMR in Solids and Heterogeneous Systems Tritium 184 References 185 Chapter 7 The Alkali and Alkaline Earth Metals: Lithium, Sodium, Potassium, Rubidium, Cesium, Beryllium, Magnesium, Calcium, Strontium, and Barium J. W. Akitt 1. Introduction to Groups I and II Experimental Techniques Aqueous Solutions of Simple Salts Nuclear Relaxation Chemical Shifts Mixed and Nonaqueous Solutions of Simple Salts Nuclear Relaxation Chemical Shifts Complexes Between the Cations and Various Types of Ligands Complexes with Low-Molecular-Weight Compounds Complexes with Synthetic Polymerie Ligands Complexes with Biopolymers Cations in Liquid Crystals Group I and II Metal Organic Compounds Lithium Organic Compounds Beryllium Covalent Compounds 215 References 215 Chapter 8 Boron John D. Kennedy 1. Nuclear Properties and General Considerations Trigonal and Tetrahedral Compounds Chemical Shifts Coupling Constants Relaxation Studies 231

6 CONTENTS XV 3. Polyhedral Boron-Containing Species General Considerations Boron Chemical Shifts Coupling Constants Relaxation Times Polyhedral Species Nuclei Other than Boron Fluxionality 252 References 253 Chapter 9 Aluminum, Gallium, Indium, and Thallium J. W. Akitt 1. The Nuclear Properties of AI, Ga, and In, the Quadrupolar Nuclei Aluminum Operational Techniques Aluminum-27 NMR Parameters Some Observations on the Parameters Gallium Operational Techniques Gallium-69 and Gallium-71 NMR Parameters Indium Indium-115 NMR Parameters Thallium 285 References 287 Chapter 10 Carbon 293 Brian E. Mann Chapter 11 Silicon, Germanium, Tin, and Lead John D. Kennedy and W. McFarlane 1. Introduction Experimental Aspects Chemical Shifts Isotope Effects Solvent and Temperature Effects Chemical Shift Patterns Factors Influencing Shielding Chemical Shifts in Specific Classes of Compound Coupling Constants One-Bond Couplings Two-Bond Couplings Three-Bond Couplings 325

7 XVI CONTENTS 5. Relaxation Behavior Miscellaneous and Solid State Work 327 References 328 Chapter 12 Nitrogen Joan Mason 1. Nitrogen NMR Spectroscopy Nitrogen Referencing Medium Effects Solid State Measurements in High Resolution Isotope Effects and Tracer Studies N NMR Spectroscopy N Relaxation and NOE Factors Sensitivity Enhancement N NMR Spectroscopy N Quadrupolar Relaxation Patterns of Nitrogen Shielding Nitrogen NMR Criteria of Structure Inorganic Azines and Azenes Coordination Shifts Nitrogen Spin-Spin Coupling Dynamics Biomolecules 362 References 362 Chapter 13 Phosphorits to Bismuth Keith R. Dixon 1. Phosphorus Introduction Spin Lattice Relaxation (7^) Chemical Shifts Coupling Constants Arsenic-75, Antimony-121,123 and Bismuth References 398 Chapter 14 Oxygen H. C. E. McFarlane and W. McFarlane 1. Introduction Experimental Aspects Chemical Shifts Spin Coupling 408

8 CONTENTS XV11 5. Relaxation Behavior Applications The Solid State 412 References 412 Chapter 15 Sulfur, Selenium, and Tellurium H. C. E. McFarlane and W. McFarlane 1. Introduction Sulfur Selenium and Tellurium Chemical Shifts Coupling Constants Relaxation Behavior Applications 431 References 432 Chapter 16 Fluorine Cynthia J. Jameson F NMR Measurements F Chemical Shifts Absolute Shielding Scale Empirical Patterns of 19 F Nuclear Shielding Anisotropy of the 19 F Shielding Tensor Spin-Spin Coupling Involving 19 F F Relaxation 445 References 445 Chapter 17 The Quadrupolar Halides: Chlorine, Bromine and lodine J. W. Akitt 1. Introduction Experimental Techniques NMR Parameters Covalent Compounds Ionic Solutions 455 References 458 Chapter 18 The Noble Gases Cynthia J. Jameson 1. Introduction Xe NMR Studies of Bonding and Structure of Xenon Compounds 463

9 Will CONTENTS Xe Chemical Shifts Spin-Spin Coupling to Xenon Probing Nonspecific Intermolecular Interactions with Noble Gas Nuclei Medium Shifts Relaxation Times 473 References 475 Chapter 19 Early Transition Metals, Lanthanides and Actinides Dieter Rehder 1. Introduction Group Illb Scandium Yttrium Lanthanum The Lanthanides Actinium and the Actinides Group IVb: Titanium, Zirconium, and Hafnium Group Vb Vanadium Niobium Tantalum Group VIb Chromium Molybdenum Tungsten Group Vllb Manganese Technetium Rhenium 512 References 512 Chapter 20 Group VIII Transition Metals R. J. Goodfellow 1. Introduction Observation Relaxation Behavior Methods of Observation Chemical Shifts Evaluation of Chemical Shifts Results Theoretical Approaches Empirical Correlations Effects of the Molecular Environment and Isotopes 548

10 CONTENTS XIX 4. Spin-Spin Coupling Sign Determinations 552 References 554 Chapter 21 Post-Transition Metals, Copper to Mercury R. J. Goodfellow 1. Introduction Observation Cu and 65 Cu Zn Ag and 109 Ag m Cd and 113 Cd Au Hg and 201 Hg Chemical Shifts Results Discussion Spin-Spin Coupling Sign Determinations 584 References 584 Chapter 22 NMR Spectroscopy in Bioinorganic Chemistry Henry W. E. Rattle 1. Introduction Some Examples of Biological Applications: Isotope Shifts in 31 P NMR Sodium Transport Through Membranes Using 23 Na Resonance Active Site Interactions in Fluorine-Labeled a-chymotrypsin Cd Studies of Alkaline Phosphatase P NMR in Living Tissue Ion Binding to Cytochrome c Studied by Nuclear Magnetic Quadrupole Relaxation Deuterium Label Studies of Membranes Direct Determination of Correlation Times in Enzyme Complexes Involving Monovalent Cations and Paramagnetic Centers 600 Index of Reviews 601 References 603 Chapter 23 Biomedical NMR Joan Mason 1. Biomedical NMR NMR Imaging 606

11 XX CONTENTS 3. Localized NMR Spectroscopy Further Applications 611 References 613 Symbols and Abbreviations 615 SI Units and Fundamental Constants 619 Appendix: NMR Properties of the Elements 623 Index 631 i