Annual Reports on NMR Spectroscopy (eBook)

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2015 | 1. Auflage
310 Seiten
Elsevier Science (Verlag)
978-0-12-802332-7 (ISBN)

Infos

Nuclear magnetic resonance (NMR) is an analytical tool used by chemists and physicists to study the structure and dynamics of molecules. 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. - This volume of Annual Reports on NMR Spectroscopy focuses on the analytical tools used by chemists and physicists, taken together with other volumes of this series, an excellent account of progress in NMR and its many applications is provided and anyone using NMR will find interest in this Serial

Inhalt

Front Cover 1
Annual Reports on NMR Spectroscopy 4
Copyright 5
Contents 6
Contributors 8
Preface 10
Chapter 1: Applications of 1H-15N Long-Range Heteronuclear Shift Correlation and 15N NMR in Alkaloid Chemistry 12
1. Introduction 13
2. Previous Reviews 14
3. Experiments and Parametric Considerations 15
3.1. 15N Chemical Shift Referencing 17
3.2. Pulse Width and Gradient Considerations 19
3.3. 15N Chemical Shift Calculation and Prediction 22
3.3.1. Validating 15N Chemical Shift Prediction 26
3.3.2. Setting F1 Spectral Windows 29
3.3.3. Structure Verification Using a 15N Content Data Base 30
3.3.4. Enhancing 15N Chemical Shift Prediction with a ``User Trained´´ Database 31
4. Computer-Assisted Structure Elucidation-The Impact of 15N Data 33
5. Covariance Calculation of 13C-15N Heteronuclear Shift Correlation Spectra 33
6. Applications of Long-Range 1H-15N Heteronuclear Shift Correlation to Alkaloids not Previously Reviewed 36
6.1. Stylissadines A and B-Tetrameric Pyrrole-Imidazole Alkaloids 36
7. Applications of Long-Range 1H-15N Heteronuclear Shift Correlation to Alkaloids 37
7.1. Five- and Six-Membered Ring Alkaloids 38
7.1.1. Characterization of Pyrrole Sulfoxides from Allium Subgenus melanocrommyum 38
7.1.2. Nagelamide T Isolated from Pacific Sponges 38
7.1.3. Characterization of Benzosceptrin C-A Bromopyrrole Alkaloid from the Sponge Agelas sp. 39
7.1.4. An Unusual 1-Phenyl-4-Pyridone Alkaloid from Aspergillus niger 39
7.1.5. Farinomalein-A Maleimide-Bearing Alkaloid from the Entomopathogenic Fungus Paecilomyces farinosus 40
7.1.6. Synthesis of 7-15N-Oroidin 41
7.1.7. Structural Characterization of Donnazoles A and B, Novel Pyrrole-Aminoimidazole Alkaloids from the Marine Sponge A... 41
7.1.8. Characterization of New Cytotoxic Thiadiazole Alkaloids from the Ascidian Polycarpa aurata 42
7.2. Tropane Alkaloids 42
7.3. Indoles, Oxindoles, and Related Alkaloids 43
7.3.1. Total Synthesis of Flustramine C 43
7.3.2. 15N CP-MAS NMR of Stereoisomeric Oxindole Alkaloids from Cat´s Claw (Uncaria tomentosa) 43
7.3.3. Secondary Prenylated Indole Alkaloids from a Marine-Derived Fungus Aspergillus carneus 45
7.3.4. Aplicyanins-Cytotoxic Bromindole Alkaloids 46
7.4. Strychnos Alkaloids 47
7.5. Azindoles 47
7.6. Vinca Alkaloids 47
7.6.1. 15N Measurements for Vinblastine and Vincristine 47
7.7. Other Indole Alkaloids 48
7.7.1. Structure and Solvent Effects on the 13C and 15N Shifts of Indoloquinoline Alkaloids 48
7.7.2. Synthesis-Driven Mapping of the Dictyodendrin Alkaloids 50
7.7.3. Structural Characterization of Pseudocerosin-An Indolic Azafulvene Alkaloid from the Flatworm Pseudoceros indicus 52
7.7.4. Aspergilazine A-A Diketopiperazine Dimer with a Rare N1-C6 Linkage 53
7.7.5. Indolo[2,3-b]quinoline Alkaloid Derivatives as Potential Anticancer Drugs 53
7.7.6. Mycoleptodiscins-Cytotoxic Alkaloids from an Endophytic Fungus 54
7.8. Carboline and Carbazole-Derived Alkaloids 56
7.8.1. Annomontine and Related Pyrimidine-ß-Carbolines 56
7.8.2. Characterization of the Imidazolyl-ß-Carboline Hyrtiocarboline 57
7.8.3. Opacalines A-C Isolated from a New Zealand Ascidian Pseudodistoma opacum. 57
7.8.4. Establishment of the Absolution Configuration of Eudistomin X 58
7.8.5. Characterization of Indolo[3,2-a]carbazoles from a Deepwater Sponge of the Genus Asteropus 59
7.8.6. Staurosporine 60
7.8.7. Characterization of Hyrtioreticulin F from the Marine Sponge H. reticulatus 60
7.8.8. Characterization of the ß-Carboline Alkaloid Hydroxymetatacarboline D from the Fungus Mycena metata 61
7.8.9. Bromine-Containing Indolocarbazole and Quinolinocarbazole Alkaloids from a Marine Sponge 61
7.9. Quinoline, Isoquinoline, and Related Alkaloids 62
7.9.1. Characterization of Thiazinoquinolinodione Alkaloids 62
7.9.2. Review of Quaternary Protoberberine Alkaloids 63
7.9.3. Covalent Bonding of Azoles to Quaternary Protoberberine Alkaloids 63
7.9.4. Characterization of Pyrrolidinyl Quinoline Alkaloids from Chestnut Honey 64
7.9.5. Characterization of Ceratinadin A-A Quinoline-Containing Bromotyrosine Alkaloid from an Okinawan Marine Sponge 64
7.9.6. Fluorescence Properties of Protopine and Allocryptopine 65
7.9.7. 15N Chemical Shifts of Papaverine Decomposition Products 66
7.10. Pyrimidine, Pyrazine, Quinoxaline, Quinazoline, and Related Alkaloids 68
7.10.1. Prenylated Quinazoline Alkaloids from a Marine-Derived Fungus Aspergillus carneus 68
7.11. Purine, Purine-Derived, and Isomerically Related Alkaloids 68
7.11.1. Nuttingins and Malonganenones-Prenylated Purine Alkaloids 68
7.11.2. Tetrabromostyloguanidine 69
7.11.3. Carteramine A-A Complex Alkaloid Isolated from the Marine Sponge Stylissa carteri 70
7.11.4. Agelasines J, K, and L from a Solomon Islands Marine Sponge 70
7.11.5. Phakellin and Isophakellin Alkaloids 71
7.11.6. Aphrocallistin-An Adenine-Substituted Metabolite of the Hexactinellida Sponge Aphrocallistes beatrix 73
7.12. Benzo[c]phenanthrene Alkaloids 74
7.13. Pyridoacridine, Quinoacridine, and Related Alkaloids 74
7.14. Phenazine Alkaloids 74
7.14.1. Solphenazines A-F-Glycosylated Phenazine Alkaloids from Streptomyces sp. Strain DL-93 75
7.15. Polyketide-Derived Alkaloids 76
7.15.1. Plakoridine C-A Novel Piperidine Alkaloid from an Okinawan Marine Sponge Plakortis sp. 76
7.15.2. Polyketide-Derived Alkaloids from Coniothyrium cereale 76
7.15.3. Sorbicillamine A-A Polyketide Alkaloid Isolated from the Deep-Sea-Derived Fungus Penicillium sp. F23-3 77
8. Miscellaneous Alkaloid Structures 78
8.1. Novel Aminoalkaloids from European Mistletoe 78
9. Alkaloid Structures Revised with the Aid of 1H-15N HMBC Data 78
9.1. Revision of the Structure of the ß-Carboline Drymaritin 78
9.2. Revision of the Structures of Diterpenoid Alkaloids from Aconitum carmichaelii 80
10. Conclusions 80
References 81
Chapter 2: Solid-State Covariance NMR Spectroscopy 88
1. Introduction 89
2. Overview of Covariance NMR Spectroscopy 91
3. Applications of Solid-State Covariance NMR Spectroscopy 95
3.1. Inorganic Materials 95
3.2. Biological Solids 98
4. Improvement of Covariance Toward Further Time Saving 102
4.1. Nonuniform Sampling 102
4.2. Accumulation Profile 103
4.3. Alternative States Sampling 103
5. Variants of Solid-State Covariance NMR Spectroscopy 107
5.1. Indirect Covariance 107
5.2. Dual Transformation 110
5.3. Heteronuclear Correlation 113
5.4. Phase Covariance 115
6. Summary 118
Acknowledgments 119
References 119
Chapter 3: Recent Advances in Chlorine, Bromine, and Iodine Solid-State NMR Spectroscopy 126
1. Introduction 127
2. Theory and Modeling 129
2.1. Interactions and Definitions 129
2.2. Second-Order Perturbation Theory versus an Exact Treatment of the Quadrupolar Interaction 130
3. Solid-State Chlorine-35/37 Nuclear Magnetic Resonance 132
4. Solid-State Bromine-79/81 Nuclear Magnetic Resonance 156
5. Solid-State Iodine-127 Nuclear Magnetic Resonance 164
6. Concluding Remarks 169
Acknowledgments 170
References 170
Chapter 4: Recent Advances in Small Molecule NMR: Improved HSQC and HSQMBC Experiments 174
1. Introduction 175
2. The Basic HSQC Experiment 179
3. Speeding-Up HSQC Data Acquisition 181
3.1. ASAP-HSQC Experiment 181
3.2. Non-uniform Sampling 183
3.3. Ultrafast HSQC 184
4. High-Resolved HSQC Using Pure Shift NMR 184
4.1. PS-HSQC Experiments 184
4.2. HOBS-HSQC: Homodecoupled Band-Selective HSQC 187
4.3. SAPS-HSQC: Spectral Aliasing and Pure-Shift NMR 189
5. HSQC Methods for Measuring 1J(CH) 193
5.1. F2-Coupled HSQC Experiments 193
5.1.1. CLIP-HSQC 195
5.1.2. J(HH)-Compensated INEPT: Perfect-HSQC 196
5.1.3. J(CH)-Compensated INEPT: COB-HSQC 199
5.1.4. PIP-HSQC Experiment 201
5.1.5. F2-Coupled Pure Shift HSQC Experiments 202
5.2. F1-Coupled HSQC Experiments 205
5.2.1. BIRD-HSQC Experiment 207
5.2.2. iINEPT Experiment 209
5.3. Strong Coupling Effects in HSQC Experiments 211
6. HSQMBC Experiments for Measuring nJ(CH) 212
6.1. CLIP-HSQMBC 214
6.2. selHSQMBC-IPAP 214
6.3. selHSQMBC-TOCSY 219
6.4. selHSQMBC-COSY-IPAP 221
6.5. HOBS-selHSQMBC 222
6.6. PIP-HSQMBC 224
6.7. Simultaneous Measurement of Multiple Coupling Constants 228
7. Other Methods 230
7.1. Quantitative HSQC 230
7.2. LR-HSQMBC 231
8. Conclusion 233
Acknowledgments 234
References 234
Chapter 5: A Review of 91Zr Solid-State Nuclear Magnetic Resonance Spectroscopy 244
1. Introduction 245
2. Experimental Methods 249
3. Chronological Literature Review 254
3.1. 1964-1990 255
3.2. 1990-2000 265
3.3. 2000-Present (2014) 275
4. Conclusions and Future Outlook 294
Acknowledgments 295
References 296
Subject Index 302

Textauszug

Chapter Two

Solid-State Covariance NMR Spectroscopy

Kazuyuki Takeda    Division of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan

Abstract

Covariance NMR spectroscopy allows acquisition of spin–spin correlation in a more efficient way compared to the traditional two-dimensional Fourier-transformation NMR spectroscopy, leading to reduction in the experimental time or increase in the sensitivity of the spectrum obtainable within a given experimental time. This chapter summarizes recent works on covariance NMR, focusing on its applications to solid-state NMR spectroscopy. In addition to a brief survey of the covariance spectroscopy, an open question of whether “inner-product” spectroscopy is more natural is posted. The usefulness of covariance NMR spectroscopy is presented by exploring its applications to solid-state systems of chemical/biological interest. A number of recent reports to further improve its efficiency or to extend the scope of its applicability are reviewed.

Keywords

Time-saving schemes

Covariance

Indirect covariance

Dual transformation

HETCOR

Phase covariance

1 Introduction

In NMR spectroscopy, the sensitivity has been the issue of general interest. The technological/methodological advances in sensitivity enhancement made so far had enabled one to reveal hitherto inaccessible structural information, strengthening NMR spectroscopy as a means for chemical analysis. Further progress in future is anticipated to push NMR spectroscopy, and thereby science, forward. That is why the sensitivity enhanced NMR continues and will continue to be an active research subject matter in the community.

The strategies toward sensitivity enhancement are diverse. One way is to increase nuclear spin polarization and thereby the macroscopic nuclear magnetization. This can be done straightforwardly either by increasing the static magnetic field or decreasing the sample temperature so as to raise the equilibrium Boltzmann population difference over the Zeeman levels. Recent remarkable magnet technology realized highly homogeneous fields of up to 23.48 T or above, corresponding to the proton resonance frequency that exceeds 1 GHz. Drastic signal enhancement is possible through nuclear hyperpolarization, which can be realized by dynamic nuclear polarization [1], optical pumping [2], and the Haupt effect [3–8].

The NMR sensitivity can also be enhanced by improving the efficiency of signal detection, instead of, or in combination with, nuclear-spin hyperpolarization. By cooling the NMR sample coil down to cryogenic temperatures, the coil resistance can be reduced. As a result, the Q-factor of the resonance circuit increases so that higher signal voltages can be extracted from the nuclear spin system. In addition, the thermal noise is expected to be suppressed as decreasing the temperature, and the overall effect is to enhance the signal-to-noise ratio. Thermal insulation between the coil and the sample was a technical challenge but had been overcome. In practice, it is necessary to cool the preamplifier as well as the sample coil, in order to gain satisfactory enhancement in the sensitivity. Probes incorporating such features are known as cryo probes [9–11] and nowadays commercially available for liquid-state NMR. Cryogenically cooled MRI probes [12, 13] and solid-state magic angle spinning (MAS) probes [14–16] have also been reported.

The detection sensitivity can be optimized by employing application-tailored experimental systems. For cases where NMR spectra of two separate spin species need to be measured one after another, an NMR system with parallel receivers [17, 18] could improve the throughput of research. When the sample of interest is unconventionally tiny, microcoil probes may be the choice [19–24]. For extremely small samples, force detection can be advantageous over the conventional Faraday detection [25–29].

In addition to such physical ways toward sensitivity enhancement, development of acquisition/data-processing methods is also an important trend. The latter has been motivated by the necessity of extracting information of chemical interest within a limited experimental time and with a reasonable cost. So far, a number of approaches have been proposed to reconstruct one-dimensional or multidimensional spectrum from a smaller number of data sets than the previous schemes require. The first example of such time-saving protocols is the maximum entropy method (MEM), which was originally developed in astrophysics [30]. Its application to NMR spectroscopy was first reported by Sibisi and coworkers [31, 32]. MEM soon found wide applications [33–37] and was combined with nonuniform sampling (NUS) scheme [38, 39]. Since then, NUS has attracted considerable interest and has been incorporated into various protocols. Other noteworthy schemes include the Hadamard spectroscopy [40–44], reduced dimensionality [45–50], single scan two-dimensional spectroscopy or ultrafast two-dimensional spectroscopy [51–54], GFT NMR [55–57], covariance spectroscopy [58, 59], recursive multidimensional decomposition [60], compressed sensing [61–66], radial sampling [67], noise and artifact suppression using resampling [68], and so on.

Even though these methods make full use of mathematics and may look formidable to NMR researchers majoring in chemistry, they are all valuable in the sense that they lifted up the limitation of NMR spectroscopy, enabling us to gain such chemical information that has not been accessible so far. In particular, the idea of covariance NMR, put forth by Brüschweiler and Zhang in solution NMR [58], has lead to a number of recent applications. The purpose of this review is to summarize recent works on covariance NMR, focusing on its applications to solid-state NMR spectroscopy. In Section 2, we overview the concept of covariance NMR, leaving at the end of the section an open question on what the author call “inner-product” NMR spectroscopy. Section 3 introduces applications of covariance NMR to solid-state systems of chemical/biological interest. In Section 4, we review sampling schemes that make the time-saving covariance NMR spectroscopy further time saving. Section 5 is devoted to describe various variants of covariance NMR spectroscopy.

2 Overview of Covariance NMR Spectroscopy

In this section, we take a brief look at what the covariance NMR spectroscopy is. For more detailed and complete description, the reader may refer to the pioneering paper published by Brüschweiler [59].

The main arena in which covariance NMR is used is two-dimensional (2D) correlation spectroscopy [69]. For a simple example, let us consider a three-spin system consisting of spins A, B, and C, as schematically depicted in Fig. 1A, and suppose that spins A and B are relatively close to each other, whereas spin C is at a distance so that J/dipolar interactions are effective only between A and B. One can employ the conventional 2D Fourier transform (2D-FT) NMR to obtain a 2D spectrum that looks like the one in Fig. 1B, where the cross-peak tells the existence of the correlation, and thereby the spatial proximity, between the relevant spins. Such information is very useful, as it provides structure constraint that can be used for studies of higher-order structure of biomolecules.

Figure 1 (A) A schematic drawing of a system of three spins labeled 1, 2, and 3. When spin 1 and spin 2 have correlation while spin 3 is isolated, the cross-peak between 1 and 2 appears, as depicted in (B).

One possible and frequent problem with 2D-FT is that relatively a large number of data arrays need to be acquired, since the spectral resolution along the indirect dimension is determined by the number of the data arrays. In particular, when the signal-to-noise ratio of the individual free induction decays (FIDs) is low, as is often the case, signal averaging over many times is necessary for each evolution time, making the overall experimental time even longer. It is not unusual for one to spend several days or more just to obtain a single 2D-FT spectrum. However, in order to improve the throughput of research, it is highly desirable to employ more efficient ways that can be used to extract the necessary information sooner.

In covariance NMR spectroscopy, pulse sequences to be used are the same as those in 2D-FT, but much fewer amounts of data sets along the indirect dimension suffice to produce a 2D spectrum similar to that obtained with 2D-FT.

Covariance is a concept in statistics, giving a measure of how much a pair of variables change in a correlated way. To explain the idea proposed by Brüschweiler of applying the covariance processing to NMR, let us suppose that we have an array of one-dimensional spectra obtained with incremented evolution time, as schematically described in Fig. 2. In this example, we have a homonuclear system of three spins, labeled with i, j, and k. For peak i and peak j, the ways that the peak amplitudes change with the...

Produkt-Details

• Erscheint lt. Verlag: 26.2.2015
• Mitarbeit: Herausgeber (Serie): Graham A. Webb
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Chemie ► Analytische Chemie
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Elektrodynamik
• Themenwelt: Technik
• ISBN-10: 0-12-802332-5 / 0128023325
• ISBN-13: 978-0-12-802332-7 / 9780128023327