In recent years, no other technique has gained such significance as NMR spectroscopy. It is used in all branches of science in which precise structural determination is required and in which the nature of interactions and reactions in solution is being studied. Annual Reports on NMR Spectroscopy has established itself as a premier means for the specialist and non-specialist alike to become familiar with new techniques and applications of NMR spectroscopy.
* Provides updates on the latest developments in NMR spectroscopy * Includes comprehensive review articles * Highlights the increasing importance of NMR spectroscopy as a technique for structural determination
In recent years, no other technique has gained such significance as NMR spectroscopy. It is used in all branches of science in which precise structural determination is required and in which the nature of interactions and reactions in solution is being studied. Annual Reports on NMR Spectroscopy has established itself as a premier means for the specialist and non-specialist alike to become familiar with new techniques and applications of NMR spectroscopy. Provides updates on the latest developments in NMR spectroscopy Includes comprehensive review articles Highlights the increasing importance of NMR spectroscopy as a technique for structural determination
Front Cover 1
Annual Reports on NMR Spectroscopy 4
Copyright Page 5
Contents 6
Contributors 8
Preface 10
Chapter 1: 129Xe NMR Studies of Xenon Adsorption 12
1. Introduction 13
2. Basic Approaches of 129Xe NMR Spectroscopy 14
2.1. Chemical shift of adsorbed xenon 14
2.2. Variation of the 129Xe chemical shift due to porosity and temperature 16
2.3. Xenon exchange spectroscopy 19
2.4. NMR of adsorbed species as a probe for metal clusters in porous materials 20
3. Microporous Carbon Materials 21
3.1. Commercially available amorphous carbon materials 22
3.2. Pitch-based activated carbon modified by air oxidation/pyrolysis cycles 25
4. Mesoporous Carbon Materials 29
4.1. Testing the nanoparticles surface: Diamond and onion-like carbon aggregates 29
4.2. Filamentous carbon: Surface, porosity and paramagnetic impurities 31
4.3. Multi-wall carbon nanotubes 37
5. Conclusions 45
References 46
Chapter 2: NMR Studies for Mapping Structure and Dynamics of Nucleosides in Water 50
1. Introduction 51
2. Overview, Trends and Opinions 53
3. Nomenclature and Symbols 54
4. About Stacking of Nucleosides in Water 60
5. Structure in Water 61
5.1. Proton and carbon-13 data 80
5.2. Investigations by other nuclei 102
5.3. Quantum mechanical calculations 109
6. Dynamics in Water 114
6.1. Rotation barrier about the glycosidic bond 114
6.2. Sugar pseudo-rotation barrier 116
6.3. Rotation barrier about the exocyclic hydroxymethyl bond 117
6.4. Rotation barrier about the exocyclic amino bond 117
6.5. Chemical exchange with water 119
6.6. Relaxation time measurements 122
6.7. Diffusion experiments 131
6.8. Microdynamics in water: A tentative interpretation 136
7. Conclusion 139
Acknowledgements 139
References 140
Chapter 3: Time-Domain NMR Applied to Food Products 156
1. Introduction 158
2. History 160
3. Equipment 161
3.1. Magnets 161
3.2. Electronics 162
4. One-Dimensional Relaxometry and Diffusometry 163
4.1. Relaxometry 163
4.2. Diffusometry 164
5. Two-Dimensional NMR Relaxometry and Diffusometry 165
5.1. T1(.)–T2 correlations 165
5.2. T2–D correlations using pulsed-field gradients 166
5.3. T1–T2 and T2–D correlations in inhomogeneous fields 167
5.4. 2D exchange experiments 167
6. Data-Analysis Approaches 168
6.1. Signal processing 168
6.2. Model-driven analysis 168
6.3. Discrete relaxometric and diffusometric decays 172
6.4. Continuously distributed relaxometric and diffusometric decays 173
6.5. Multi-variate data analysis approaches 174
7. Benchtop Time-Domain NMR Applications 174
7.1. Solid fat content 174
7.2. Shelf-life stability of foods 176
7.3. Moisture and fat content 176
7.4. Microstructural features in food emulsions 177
7.5. Functionality of food ingredients 179
7.6. Functionality of heterogeneous food products 188
8. Mobile Time-Domain NMR Applications 196
8.1. Unilateral NMR sensors 196
8.2. Online quality inspection 196
9. Perspectives and Conclusions 197
9.1. Hardware 197
9.2. Fast measurements 197
9.3. In situ measurements 198
9.4. Enhancing information yield from the time-domain 198
Acknowledgement 198
References 198
Chapter 4: From Helical Jump to Chain Diffusion: Solid-State NMR Study of Chain Dynamics in Semi-Crystalline Polymers 210
1. Introduction 211
2. NMR Strategies for Probing Chain Dynamics in Solid Polymeric Materials 211
2.1. Spin–lattice relaxation measurement 212
2.2. Probing motionally modulated/averaged NMR interaction 212
2.3. Longitudinal spin exchange experiment 214
3. Helical Jump and Chain Diffusion in Semi-Crystalline Polymers 215
3.1. Helical jump in polymer crystals 216
3.2. Chain diffusion in semi-crystalline polymers and its influencing factors 219
3.3. The correlation between helical jump and chain diffusion 229
Acknowledgements 234
References 234
Subject Index 236
Color Plates 244
3. Nomenclature and Symbols
Figure 2 Chemical structure of the most common purine nucleosides (Pus). |
Figure 3 Chemical structure of the most common pyrimidine nucleosides (Pys). |
Figure 4 (A) The torsion angle ? in uridine U and the definition of the torsion angles ? 0, ? 1, ? 2, ? 3 and ? 4 in the ribose ring. (B) Conformational model for the glycosidic torsion angle ? in nucleosides for Pys (O 2) and for Pus (N 3) showing the anti and syn ranges and denoting the four symmetric quadrants (dashed lines). |
- ? The glycosidic linkage torsion angle ?, O4??C1??N1?C2 (?, Pys) and O4??C1??N9?C4 (?, Pus), is pictured in Figure 4A , Section 5.1.1.1 , for U. According to this definition, the syn conformation is in the range ? = 0 ± 90°, whereas the anti conformation is in the range ? = 180 ± 90° ( Figure 4B ).
- ? The pseudo-rotation of the furanose ring or sugar puckering mode is illustrated in Figure 5A , with the two most common states of the ribose cycle, the C2? endo (referred to as 2E, or S-type) and the C3? endo (referred to as 3E, or N-type) represented in Figure 5B . Endocyclic torsion angles of the sugar are denoted ? 0 to ? 4, P is the pseudo-rotation phase angle and ? m is the maximum torsion angle which describes the maximum out-of-plane pucker, according to the usual convention. 41 , and 73 They are exemplified on U in Figure 4A .
Figure 5 (A) The pseudo-rotational wheel of the ribose sugar in nucleosides. The dashed angle represents the phase angle of 36°. Envelope E and twist T alternate every 18°. After rotation by 180°, the mirror image of the starting position is found as schematised for the North position and the South position in the hatched part. (B) Schematic representation of the ribose equilibrium between the two states N and S: C3?, endo ( 3E, N) ? C2?, endo (2E, S). P = 0° and P = 180° are the phases along the pseudo-rotation cycle. - ? The three main rotamers in staggered conformations gg, gt and tg as obtained by rotation about the exocyclic C4? ?C5? bond in the ribose moiety are drawn in Figure 6 , as Newman projections about this bond.
Figure 6 Newman projections showing the three main staggered conformations about the C4?–C5? exocyclic bond.
- (a) C-Nucleosides such as pseudo-uridine (? uridine, symbolised as ?U hereafter) which occurs ubiquitously as a minor component in various tRNAs. 85 , 86 , and 87 and a large number of C-analogues which have been the cornerstone of antiviral and anticancer chemotherapy over the past three decades. 72 , 86 , 87 , and 88
- (b)
- (c)
- (d)
- (e)
- (f)
- (g) 5?- O-Amino-2?-deoxy-nucleosides which are building blocks for antisense oligonucleotides and have recently gained much attention for their usefulness in antisense therapy. 102
- (h) ?-Nucleosides which are conformational enantiomers of the common nucleosides with the anomeric carbon C1? in an inverted configuration and are found in vitamin B-12 and in arabino-nucleosides which differ from their ribo analogues in the altered configuration at C2? and exhibit broad antiviral activity against DNA-containing viruses as well as against RNA tumour viruses. 103
Erscheint lt. Verlag | 12.4.2010 |
---|---|
Sprache | englisch |
Themenwelt | Naturwissenschaften ► Chemie ► Analytische Chemie |
Naturwissenschaften ► Physik / Astronomie ► Elektrodynamik | |
Technik | |
ISBN-10 | 0-12-381354-9 / 0123813549 |
ISBN-13 | 978-0-12-381354-1 / 9780123813541 |
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