Mục lục
Foreword xiii
Preface xv
Foreword xvii
1 Introductory NMR Concepts 1
1.1 Historical Aspects 1
1.2 Basic Description of NMR Spectroscopy 5
1.2.1 Nuclear Spins and Nuclear Zeeman Effect 8
1.2.2 Spin Ensembles 11
1.2.3 Single Pulse Experiment, Bloch Equations, and Fourier Transformation 17
1.2.4 Populations and Coherences 27
1.3 Liquid-state NMR Spectroscopy: Basic Concepts 29
1.3.1 Chemical Shift 29
1.3.2 Indirect Spin–Spin Coupling and Spin Decoupling 32
1.3.3 Nuclear Spin Relaxation 38
1.3.4 Nuclear Overhauser Effect 44
1.4 Liquid-state NMR Spectroscopy: Some Experiments 47
1.4.1 Relaxation Experiments 47
1.4.2 Insensitive Nuclei Enhanced by Polarization Transfer 53
1.4.3 2D NMR Spectroscopy 53
1.4.4 Chemical Exchange 57
1.5 Solid Materials and NMR Spectroscopy 63
References 69
2 Mathematical and Quantum-mechanical Tools 73
2.1 Definitions and Basic Concepts 73
2.1.1 Operators and Functions 73
2.1.2 Eigenvalue Equations 74
2.1.3 Eigenstates and Superposition States: Pure and Mixed Ensembles 75
2.1.4 Nuclear Spin and Angular Momentum 76
2.2 Rotations and Frame Transformations 77
2.2.1 Active and Passive Transformations 78
2.2.2 Rotation Operators 78
2.2.3 Rotation Matrices and Euler Angles 79
2.3 Time-Independent Features: Energy Levels and Related Aspects 81
2.3.1 Time-Independent Schrödinger Equation and Spin Hamiltonians 81
2.3.2 Time-Independent Perturbation Theory 81
2.3.3 Matrix Representation of Operators and Density Matrix Theory 83
2.3.3.1 Isolated Nucleus with Spin 1/2 84
2.3.3.2 Isolated Nucleus with Spin 1 87
2.3.3.3 Pair of Coupled Nuclei with Spin 1/2 87
2.3.4 Spin Temperature 89
2.4 Dealing with Time Dependence 90
2.4.1 Time-Dependent Schrödinger and Liouville–von Neumann Equations 90
2.4.2 Average Hamiltonian Theory 91
References 93
3 Nuclear Spin Interactions 95
3.1 Introduction 95
3.2 Interactions with External Magnetic Fields 97
3.3 Internal Interactions 100
3.3.1 Shielding or Chemical Shift Interaction 100
3.3.2 Knight Shift Interaction 105
3.3.3 Quadrupolar Interaction 106
3.3.4 Dipolar Coupling 112
3.3.5 Indirect Spin–Spin (J) Coupling 116
3.3.6 Paramagnetic Coupling 117
References 119
4 Broadline NMR Spectroscopy 121
4.1 Introductory Remarks 121
4.2 Finite Pulse Duration and Adiabatic Pulses 133
4.2.1 Finite Pulse Duration: Excitation Profile and Spectral Distortions 133
4.2.2 Adiabatic Pulses 138
4.3 Inhomogeneous and Homogeneous Line Broadening Mechanisms 141
4.4 Dilute Spin-1/2 Nuclei 142
4.4.1 Broadline NMR Spectra 142
4.4.2 Cross-polarization 149
4.4.2.1 Pulse Sequence and Hartmann–Hahn Conditions 149
4.4.2.2 CP Explained by AHT 151
4.4.2.3 CP Explained by the Thermodynamic Model 157
4.4.2.4 CP Dynamics 160
4.4.2.5 CP-related Techniques 167
4.4.3 Heteronuclear Spin Decoupling 169
4.4.3.1 CWHeteronuclear Spin Decoupling Explained by AHT 171
4.4.3.2 Beyond CW: Off-resonance Effects and Pulse Decoupling Schemes 172
4.4.4 Echo Experiments 176
4.5 Abundant Spin-1/2 Nuclei 184
4.5.1 Broadline NMR Spectra 184
4.5.2 Spin Diffusion 187
4.5.2.1 Fick’s Equation of Diffusion 187
4.5.2.2 The Goldman–Shen Experiment 189
4.5.2.3 Influence of Spin Diffusion on Spin-Lattice Relaxation Times 191
4.5.3 Moment Analysis 192
4.5.4 Echo Experiments for Refocusing the Homonuclear Dipolar Interaction 194
4.5.4.1 Solid Echo 194
4.5.4.2 Magic-sandwich Echo 197
4.6 Quadrupolar Nuclei 200
4.6.1 Broadline NMR Spectra 200
4.6.2 Selective and Non-selective RF Pulses 205
4.6.3 Cross-polarization 209
4.6.4 Echo and Sensitivity Enhancement Experiments 210
4.6.4.1 Quadrupolar Echo 210
4.6.4.2 Solomon and Hahn Echoes 211
4.6.4.3 Quadrupolar Carr–Purcell–Meiboom–Gill 218
4.6.4.4 Other Sensitivity Enhancement Techniques 219
References 224
5 1D High-resolution Solid-state NMR Spectroscopy 227
5.1 Dilute Spin-1/2 Nuclei 227
5.1.1 Sample Rotation 228
5.1.2 Spinning Sideband Suppression 236
5.1.3 Heteronuclear Spin Decoupling and Sample Spinning 244
5.1.4 Cross-polarization and Sample Spinning 257
5.1.5 Basic Pulse Experiments Under MAS Conditions 268
5.1.5.1 Pulse Sequences for the Measurement of Relaxation Times 269
5.1.5.2 Pulse Sequences for Spectral Editing: Distinguishing Components with Different Dynamic Properties 270
5.1.5.3 Pulse Sequences for Spectral Editing: Distinguishing Rare Nuclei With Different Chemical Bonds 271
5.1.5.4 Pulse Sequences for Quantitative Determinations: CP vs SPE 273
5.2 Abundant Spin-1/2 Nuclei 275
5.2.1 Sample Rotation 275
5.2.2 Multiple Pulse Experiments 275
5.2.3 Combined Pulse and Sample Rotation Experiments 282
5.3 Quadrupolar Nuclei 289
5.3.1 Sample Rotation 289
5.3.2 Integer Spin Nuclei 290
5.3.3 Half-integer Spin Nuclei 291
5.3.3.1 CT Spectra 294
5.3.3.2 Double Angle Rotation 297
5.3.3.3 Satellite Transition Spectroscopy 300
5.3.4 Sensitivity Enhancement 301
References 305
6 2D Solid-State NMR Spectroscopy 309
6.1 Basic Concepts 311
6.1.1 Basic Structure of 2D Experiments 311
6.1.2 Need for Recoupling 313
6.1.3 Double (Multiple) Quantum Spectroscopy 316
6.2 Experiments Based on Chemical Shift Anisotropy 317
6.2.1 MAH, MAT, 5-π, and Related Experiments 318
6.2.2 STAG, S3, SASS 321
6.2.3 VACSY 322
6.2.4 TOSS–Reverse TOSS and 2D-PASS 322
6.2.5 CSA Amplification Methods 324
6.2.6 Pulse Sequences Recoupling Chemical Shift Anisotropy 326
6.2.7 Pulse Sequences for Abundant Spin-1/2 Nuclei 326
6.2.8 Rotary Resonance (RR) 328
6.3 Experiments Based on Heteronuclear Dipolar Coupling 329
6.3.1 Heteronuclear Correlation Through Dipolar Interaction 330
6.3.2 Separated Local Field (SLF) 333
6.3.3 Rotary Resonance Recoupling (R3) 337
6.3.4 REDOR 337
6.3.5 REAPDOR and TRAPDOR 348
6.3.6 TEDOR 352
6.3.7 HARDSHIP 354
6.4 Experiments Based on Homonuclear Dipolar Coupling 355
6.4.1 WISE 355
6.4.2 Rotational Resonance (R2) 358
6.4.3 Broadband Homonuclear Dipolar Recoupling 360
6.4.3.1 DRAMA and MELODRAMA 362
6.4.3.2 RFDR and SEDRA 365
6.4.3.3 2Q-HORROR, MSD-HORROR, and DREAM 366
6.4.3.4 BABA 370
6.4.3.5 Symmetry-based Recoupling Schemes: C7 and POST-C7 370
6.4.3.6 Dipolar Truncation and High-order Recoupling Schemes 371
6.4.4 Homonuclear Correlation Through Dipolar Interaction 372
6.5 Experiments Based on J-coupling 375
6.5.1 Heteronuclear Correlation Through J-coupling 376
6.5.2 Homonuclear Correlation Through J-coupling 378
6.6 Experiments Based on Quadrupolar Interaction 380
6.6.1 Nutation 380
6.6.2 DAH and DAS 381
6.6.3 MQMAS 384
6.6.4 STMAS 388
References 391
7 Molecular Dynamics by Solid-State NMR 397
7.1 Experimental Observables and Motional Timescales 399
7.1.1 Spectral Lineshapes 399
7.1.1.1 High-Resolution Spectra 400
7.1.1.2 Powder Spectra 401
7.1.1.3 Spectra Acquired by “Exchange” Experiments 403
7.1.2 Relaxation Times in Solids 404
7.1.2.1 Spin–Spin Relaxation Times 406
7.1.2.2 Spin–Lattice Relaxation Times of Abundant Nuclei 409
7.1.2.3 Spin–Lattice Relaxation Times of Rare Nuclei 410
7.1.2.4 Dipolar and Quadrupolar Spin–Lattice Relaxation Times 411
7.1.2.5 Theory of Relaxation 412
7.1.3 Absolute Frequency Regimes 416
7.2 Motional Models 419
7.2.1 Models for Lineshape Analysis 419
7.2.2 Spectral Densities 422
7.2.3 Dependence of Correlation Times on Temperature 423
7.3 Broadline Experiments 424
7.3.1 Acquisition of 1D Spectra 425
7.3.2 Measurement of Relaxation Times 426
7.3.2.1 Spin–Spin Relaxation Times, FID Analysis, and DQ Techniques 426
7.3.2.2 Spin–Lattice Relaxation Times 432
7.3.3 Other Techniques 435
7.3.3.1 Stationary Stimulated Echo 436
7.3.3.2 2D Exchange 436
7.3.3.3 Spin Alignment 437
7.4 High-Resolution Experiments 438
7.4.1 Acquisition of 1D and 2D Spectra 438
7.4.1.1 1D Chemical Exchange 438
7.4.1.2 Line Broadening from Interferences 439
7.4.1.3 Lineshapes from 2D Experiments 440
7.4.2 Measurement of Relaxation Times 440
7.4.2.1 Abundant Nuclei 440
7.4.2.2 Rare Nuclei 441
7.4.3 Other Techniques 442
7.4.3.1 2D Chemical Exchange 442
7.4.3.2 1D and 2D Exchange of Spinning Sidebands 442
7.4.3.3 CODEX 443
References 444
8 Application of SSNMR to Selected Classes of Systems 447
8.1 Pharmaceuticals 447
8.1.1 Introduction 447
8.1.2 Polymorphs, Solvates, and Salts 449
8.1.3 Molecular Complexes and Cocrystals 454
8.1.4 NMR Crystallography 456
8.1.5 Molecular Dynamics 459
8.1.6 Disordered and Amorphous Forms 461
8.1.7 Identification of API Forms in Formulations 461
8.1.8 Miscibility and Interactions in Drug Formulations and Dispersions 463
8.2 Polymeric Materials 465
8.2.1 Introduction 465
8.2.2 Primary Structure 466
8.2.3 Secondary and Tertiary Structure 466
8.2.4 Phase Properties 470
8.2.4.1 Polymorphism 470
8.2.4.2 Heterophasicity 470
8.2.4.3 Phase Transformations 474
8.2.5 Interfaces and Domain Dimensions 474
8.2.6 Molecular Dynamics 479
8.2.6.1 Motions in Glassy and Crystalline Phases 480
8.2.6.2 Motions in Rubbers and Melts 481
8.3 Inorganic and Organic–Inorganic Materials 485
8.3.1 Introduction 485
8.3.2 Inorganic Systems 486
8.3.2.1 Silicates 486
8.3.2.2 Zeolites 489
8.3.2.3 Aluminophosphates 491
8.3.2.4 Amorphous Materials: Cements, Geopolymers, and Glasses 493
8.3.3 Organic–Inorganic Materials 497
8.3.3.1 Organometallic Complexes 497
8.3.3.2 Metal–Organic Frameworks 500
8.3.3.3 Organically Modified Fillers and Polymer/Filler Composites 502
8.4 Liquid Crystals and Model Membranes 507
8.4.1 Introduction 507
8.4.2 Mesogens and Mesophases 507
8.4.3 SSNMR Techniques for Investigating Mesophases 511
8.4.4 Orientational Order 515
8.4.5 Phase Structure 519
8.4.6 Molecular Dynamics 523
References 525
Index 531
