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