Preface ........................................................ xi
Author ......................................................... xv
Chapter 1 General Principles of Pulsed NMR and NMR Techniques .. 1
1.1 Early History of NMR in the Solid State .................... 2
1.2 Nuclei in the External Magnetic Field ...................... 3
1.3 Effects of Radio Frequency Pulses .......................... 9
1.4 From Macroscopic Magnetization to Nuclear Relaxation
and Shapes of NMR Signals ................................. 12
1.4.1 Common Representations of Molecular Motions and
Their Influence on NMR ............................. 14
1.4.2 Contribution of Molecular Mobility to Spin-Spin
and Spin-Lattice Nuclear Relaxation ................ 17
1.5 Parameters Characterizing Nuclei in the External
Magnetic Field ............................................ 20
1.5.1 Chemical Shift ..................................... 20
1.5.2 Spin-Spin Coupling ................................. 22
1.5.3 Quadrupolar Coupling ............................... 24
1.6 Introducing NMR Equipment and NMR Experiments ............. 26
1.6.1 Magnets and NMR Probes ............................. 28
1.6.2 Homogeneity of the External Magnetic Field and
Digital Resolution in NMR Spectra .................. 30
1.6.3 Dead Time of NMR Spectrometers: Intensity of
Signals and Distortion of Baselines in NMR
Spectra ............................................ 30
1.7 Main Principles of Two-Dimensional NMR .................... 32
1.8 Enhancement of Sensitivity in NMR ......................... 34
References ................................................ 35
Chapter 2 On Amorphous Materials as Potential Objects in
Solid-State NMR Studies: Common and Key Problems ............... 37
2.1 Hybrid Materials .......................................... 38
2.2 Polymer Solids ............................................ 40
2.3 Systems Based on Nanostructures ........................... 41
2.4 Wood and Wood Components .................................. 42
2.5 Glasses ................................................... 44
2.6 Zeolites .................................................. 45
2.1 and the CRC Press Web site at http://www.crcpress.com
2.7 Design of Porous and Layered Molecular Systems ............ 47
2.7.1 General Problems in Structural Characterizations
of Amorphous Porous Materials ...................... 48
2.7.2 Some Key Structural Issues in Characterizations
of Amorphous Materials Modified by Metal Ions
and Methods for Structure Solution ................. 50
References ................................................ 54
Chapter 3 Features of Solid-State NMR: Diamagnetic Materials .. 57
3.1 From Isotropic Chemical Shifts to Magnetic Shielding
Tensors ................................................... 57
3.1.1 Visualization of Chemical Shift Tensors and
Determination of Their Orientations ................ 62
3.2 Nuclei with a Spin of 1/2 ................................. 66
3.3 Quadrupolar Nuclei in Solids .............................. 70
3.3.1 Two Categories of Quadrupolar Nuclei ............... 72
3.4 Detection of NMR Signals in Solids: Common Aspects ........ 73
3.4.1 Wide-Line NMR ...................................... 73
3.4.2 Direct Excitation .................................. 74
3.4.3 Cross-Polarization ................................. 76
3.4.4 Cross-Polarization with Quadrupolar Nuclei ......... 79
3.5 High-Power Decoupling ..................................... 81
3.6 Multi-Quantum NMR Experiments ............................. 83
3.7 Dipolar Recoupling NMR Techniques ......................... 85
3.8 Sideband Manipulations .................................... 90
3.9 Zero-Field Solid-State NMR Experiments .................... 92
3.10 Solid-State NMR Imaging ................................... 94
References ..................................................... 96
Chapter 4 Practice of Multinuclear NMR in Diamagnetic
Solids: General Information and Examples of Applications ....... 99
4.1 Structural Information by Increasing the Spectral
Resolution in Multinuclear Solid-State NMR ................ 99
4.1.1 Spectral Resolution for Nonquadrupolar Nuclei ..... 100
4.1.2 Signal Assignments ................................ 102
4.1.3 Resolving Quadrupolar Nuclei ...................... 104
4.2 Probing Proximities of Nuclei and Measurements of
Internuclear Distances in Diamagnetic Solids ............. 106
4.3 31P Solid-State NMR ...................................... 11l
4.4 Solid-State NMR of Halogen Nuclei and Oxygen ............. 116
4.5 Solid-State NMR of Oxide Materials: Nuclei 51V, 93Nb,
and 181Ta ................................................ 123
4.6 Solid-State 13C NMR: Wood and Wood Products .............. 127
4.7 2H NMR in Solids at Deuterium Natural Abundance .......... 129
4.8 Between Solution- and Solid-State NMR: Nanoparticles
and Suspensions .......................................... 131
References .................................................... 137
Chapter 5 Dynamics in Diamagnetic Materials from Solid-
State NMR: Methods, Measurements, and Analysis ................ 139
5.1 Variable-Temperature Solid- State NMR Experiments and a
Line-Shape Analysis ...................................... 141
5.1.1 Dynamics in Polymeric Materials from a Line-
Shape Analysis .................................... 143
5.2 Molecular Mobility from the Solid-State NMR Relaxation ... 145
5.2.1 Measurements of Relaxation Times and Errors of
the Measurements .................................. 145
5.2.2 How Molecular Motions Affect Nuclear Relaxation ... 149
5.2.2.1 Correlation Time Distribution versus
Single Correlation Time .................. 151
5.2.3 Relaxation Approaches: Methodology and Examples ... 153
5.3 One- and Two-Dimensional Exchange Solid-State
NMR Spectroscopy ......................................... 156
5.4 Molecular Mobility from the Cross-Polarization NMR
Experiments .............................................. 158
5.5 Molecular Mobility from Magnetic Relaxation Dispersion
Experiments .............................................. 160
References .................................................... 163
Chapter 6 Strategies in Solid-State Multinuclear NMR:
Studies of Diamagnetic Porous Materials ....................... 165
6.1 Porosity of Materials from NMR ........................... 165
6.1.1 NMR Cryoporometry ................................. 168
6.1.2 NMR Relaxometry ................................... 171
6.1.3 NMR Behavior of Gases in Pore Spaces .............. 173
6.2 Structural Features of Silica Lattice and Surface
by Solid-State 1H 29Si, 27Al, and 17O NMR Spectra ........ 176
6.2.1 Distribution of Diamagnetic Metal Ions from
Solid-State NMR ................................... 181
6.3 Molecular Mobility in Diamagnetic Porous Materials ....... 186
References .................................................... 189
Chapter 7 Paramagnetic Effects in Solid-State NMR ............ 191
7.1 Theoretical Aspects ...................................... 193
7.1.1 Chemical Shifts and Magnetic Shielding Tensors
in the Presence of Unpaired Electrons ............. 193
7.2 Nuclear Relaxation in the Presence of Unpaired
Electrons ................................................ 197
7.2.1 Spin Diffusion .................................... 198
7.2.2 Nuclear Relaxation via Nucleus-Electron Dipolar
and Contact Interactions .......................... 199
7.3 Practical Consequences from the Theory of Paramagnetic
Effects .................................................. 200
7.4 1H, 31P, 13C, 2H,29Si, 51Li, and 6Li NMR Spectra of
Paramagnetic Solids ...................................... 205
7.5 51V and 55Mn NMR Spectra of Paramagnetic Solids .......... 210
7.5.1 Analyzing the Nature of Metal Ions by Their
Direct Observation in Solid-State NMR Spectra ..... 212
7.6 Special NMR Techniques for Observations of "Invisible"
Target Nuclei ............................................ 215
7.7 Relaxation Measurements and Relaxation Times in
Paramagnetic Solids ...................................... 217
7.7.1 Solid-State T1 Measurements ....................... 224
7.7.2 Spin-Spin Relaxation Times and Anomalies in
Solid-State T2 Measurements ....................... 225
References .................................................... 228
Chapter 8 Strategy in NMR Studies of Amorphous Porous
Paramagnetic Materials ........................................ 231
8.1 Intense Sideband Patterns in MAS NMR Spectra of
Paramagnetic Amorphous Materials and Their Analysis ...... 231
8.2 Direct Detection of the Nuclei Closest to Paramagnetic
Ions in Porous Materials by the Hahn-Echo Mapping
NMR Experiments .......................................... 236
8.3 NMR Relaxation Approaches to Structure of Porous
Amorphous Paramagnetic Silica-Based Materials: From
Experiments to Models and Interpretations ................ 240
8.3.1 Factors Affecting Relaxation Times in Porous
Solids ............................................ 241
8.3.2 Spin-Lattice Relaxation Times in Porous Silica-
Based Materials and Concentrations of
Paramagnetic Ions ................................. 242
8.3.3 29Si Spin-Lattice and Spin-Spin Relaxation
in Static and Spinning Porous Amorphous
Paramagnetic Silica-Based Materials ............... 243
8.3.4 T1 Criteria for Locations of Paramagnetic Ions:
Relaxation of Isotropic Resonances ................ 247
8.3.5 T1 Criteria Based on Relaxation of Sideband
Patterns in MAS Spectra of Porous Paramagnetic
Materials ......................................... 251
8.3.6 BMS Effects and NMR Relaxation of Sideband
Patterns in MAS Spectra of Porous Paramagnetic
Materials ......................................... 254
Protocol for Quantification of "Invisible Nuclei" in MAS NMR .. 255
8.5 Concluding Remarks ....................................... 256
References .................................................... 257
Index ......................................................... 259
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