Modern NMR Books tnG,and Wokaun人19g7 ta- 波解为发年史整的块整子 原理)教国际NMR领 instrument called an NMR Spectrometer Rrs0H NMR Spectromet The hox houses the source of the radiofrequeney r
1 31 1. Derome, A. 1987. Modern NMR Techniques for Chemistry Research. Pergamon Press Press, Oxford. 2. Ernst RR., Bodenhausen G., and Wokaun A.. 1987. Principles of Nuclear Magnetic Resonance in One and Two Dimensions. Clarendon Press, Oxford. Modern NMR Books R. R. Ernst及其学生G. Bodenhausen 和A. Wokaun 合作 1987年出版《一维和二维核磁共振原理》，此书与A. Abragam 1961年出版的专著《核磁学原理》被国际NMR领 域称为NMR发展史上的两块里程碑. 32 NMR spectra are acquired on a special instrument called an NMR Spectrometer 33 Bruker 500 MHz NMR Spectrometer 34 Varian 600 MHz NMR Spectrometer 35 Liquid Helium-cooled Magnet 36 The box houses the source of the radiofrequency radiation
2 37 38 39 40 41 42
retically,one may obtain complet e2D NMR dataset er BioSpin 200 ral days af h lor a n the ab sigmals of a dilut 72Mk 园 I prod ions are use of lo
3 43 The technique is challenging to learn but wonderfully powerful for the determination of organic and biochemical structure. 44 900 MHz NMR 伯明翰HWBNMR中心的 900 MHz核磁 谱仪 45 46 Theoretically, one may obtain complete 2D NMR datasets on, say, ca. 1 mg of a natural product of MW ca. 1000 (1 nmol) if several days of acquisition time are available, but few can afford this luxury. A more important limitation for a natural products chemist working with small-molecular mass samples is dynamic range – the ability to detect weak signals of a dilute solution of a natural product from strong background signal (e.g. residual NMR solvent signals or even impurities within the NMR solvent). Dynamic range limitations are ameliorated by the use of low-volume probes in which relatively high sample concentrations can be maintained. 47 5 mm (600 µL), 1.7 mm (35 µL) and 1 mm tubes (7 µL). Right, a gas-tight sample syringe fitted with an extra long needle. Image credit: D. S. Dalisay. Fig. 1 Relative NMR sample tube diameter (OD) and sample volumes. From left to right, Tadeusz F. Molinski. NMR of natural products at the ‘nanomole-scale’. Nat. Prod. Rep., 2010, 27, 321-329. 48 Fig. 1 Approximate time-line and qualitative comparison of recent milestone NMR probe innovations.Mass sensitivity (Sm, linear ‘y’ scale) for 1H NMR of a hypothetical fixed-mass sample as a function of probe fill volume (Vf, note the logarithmic ‘x’ scale) for room temperature probes (red line) and cryoprobes (blue line) at fixed field, Bo. See text for key references. NanoprobeTM is a trademark of Varian Inc
ruker 9 Two Bruker 400 MHz DPX-400 Spectrometers H NMR 核磁共振波谱分析法的特点及应用范围 ntegrate,Enlarge and Prin 的肉分桥用
4 49 Fig.1. Schematic of the setup and probe design for CapNMR spectroscopy. CE=capillary electrophoresis. In CapNMR the sample has to be dissolved in only 5–10 μL of solvent. 50 51 Bruker 700 MHz Avance III Spectrometer with carbon-optimized cryoprobe This instrument is one of the most sensitive carbondetecting magnets in the world - capable of measuring a high quality carbon spectrum on 1000+ molecular weight samples as small as 0.1 mg. 52 Two Bruker 400 MHz DPX-400 Spectrometers 53 (1) NMR是化合物分子结构分析的最重要方法之一。尤其适 用于不能获得单晶的化合物或液体（包括溶液中）的化合物 的构型、构象的结构分析。 (2) 灵敏度比较低。一般要用mg以上的试样作测试，很少作 定性分析。定量分析精确度、准确度较差。 (3) 在化学反应动力学方面有独特的应用。可用于研究分子 内部基团的运动（内旋转），测定反应速度常数，也可以监 视一些化学反应的进行过程。 (4) NMR spectra are capable of supplying information about molecular interactions in solution. When a drug interacts with a receptor in a reversible manner, a number of effects may be observed in the spectra due to the exchange of the molecules between free and bound states. 核磁共振波谱分析法的特点及应用范围 54 Integrate, Enlarge and Print 1H NMR
NMR NMR NMR spectra have heen a major tool for the study of elements bydrogem Additi are the Nature since 1950 :1980s a se Eath of these elements has an i ucleus which ca detected by the s and the a ated Fourier transfo The bow ed the very large e the without the use of NMR Principles For organic structure determination.the two most important types of NMR spectra are the information about the number of bydro vation of atoms pos carbons in a malecule and how those bydrogen NMR sig is strictly linear by proportiona to the amount of atoms in the probe volume.The and carbons are connected tosether as well as information about functional groups.NMR signals are a measure of molar ratios of complements IR for determination of structures molecules,independent of the molecular weight. of organic compounds. NMR Spectrum Disadvantage Compared to conventional methods.NMR An obvious limitation of NMR offers severadch che technique,however,concerns the determination of absolute configuration mples of the ord native form,and performed in a reasonable time which must be achieved by conventiona procedures. without degradation or chemical modification
5 55 NMR spectra have been a major tool for the study of both newly synthesized and natural products isolated from Nature since 1950s. In the 1980s a second revolution occurred. The introduction of reliable superconducting magnets combined with newly developed, highly sophisticated pulse techniques and the associated Fourier transformation provided the chemist with a method suitable to determine the 3-dimensional structure of very large molecules, e.g. biomacromolecules. NMR 56 Organic compounds are composed basically of the elements hydrogen, carbon, phosphorus, nitrogen and oxygen. Additionally, there are the halogens fluorine, chlorine, bromine and iodine and sometimes metal atoms. Each of these elements has an isotopic nucleus which can be detected by the NMR experiment. The low natural abundance of 15N and 17O in nature prevents NMR being routinely applied to these elements without the use of labelled substances, but 1H-, 13C-, 19F- and 31P NMR spectroscopy are daily routine work. NMR 57 For organic structure determination, the two most important types of NMR spectra are the proton and carbon spectra. They give information about the number of hydrogens and carbons in a molecule and how those hydrogens and carbons are connected together as well as information about functional groups. NMR complements IR for determination of structures of organic compounds. NMR 58 The NMR experiment makes the direct observation of atoms possible. The integral of an NMR signal is strictly linear by proportional to the amount of atoms in the probe volume. The signals are a measure of molar ratios of molecules, independent of the molecular weight. Principles 59 Compared to conventional methods, NMR offers several advantages. It is a non-destructive and reproducible technique, which can be applied to samples of the order of few milligrams in their native form, and performed in a reasonable time without degradation or chemical modification. NMR Spectrum 60 An obvious limitation of NMR technique, however, concerns the determination of absolute configuration which must be achieved by conventional procedures. Disadvantage
