Applications of NMR spectroscopy

Application of NMR spectroscopy to heterocyclic chemistry has developed very rapidly during the past 15 years, and the technique is now used almost as routinely as H NMR spectroscopy. There are four main areas of application of interest to the heterocyclic chemist (i) elucidation of structure, where the method can be particularly valuable for complex natural products such as alkaloids and carbohydrate antibiotics (ii) stereochemical studies, especially conformational analysis of saturated heterocyclic systems (iii) the correlation of various theoretical aspects of structure and electronic distribution with chemical shifts, coupling constants and other NMR derived parameters and (iv) the unravelling of biosynthetic pathways to natural products, where, in contrast to related studies with " C-labelled precursors, stepwise degradation of the secondary metabolite is usually unnecessary. 

G. Binsch, Top. Stereochem. 3 97 (1968) F. G. Riddell, Nucl. Magn. Reson. 12 246 (1983) J. Sandstrom, Dynamic NMR Spectroscopy Academic Press, New %rk, 1982 J. L. Marshall, Nuclear Magnetic Resonance, Veilag Chemie, Deerfield Beach, Florida, 1983 M. Oki, Applications of Dynamic NMR to Organic Chemistry, VCH Publishers, Deerfield Beach, Florida, 1985 Y. Takeuchi and A. P. Marchand, eds.. Applications of NMR Spectroscopy in Stereochemistry and Corformationol Analysis, VCH Publishers, Deerfield Beach, Florida, 1986. 

The application of NMR spectroscopy to tacticity determination of synthetic polymers was pioneered by Bovey and Tiers.9 NMR spectroscopy is the most used method and often the only technique available for directly assessing tacticity of polymer chains. "2 7 8 0JI The chemical shift of a given nucleus in or attached to the chain may be sensitive to the configuration of centers three or more monomer units removed. Other forms of spectroscopy (e.g. TR spectroscopy l2 lJ) are useful with some polymers and various physical properties (e.g. the Kerr effect14) may also be correlated with tacticity. 

Bhacca, N., Williams, D. Application of NMR Spectroscopy in Organic Chem., Moscow, Mir Publishers 1966, (Russ. Transl.)... 

The optically active Schiff bases containing intramolecular hydrogen bonds are of major interest because of their use as ligands for complexes employed as catalysts in enantioselective reactions or model compounds in studies of enzymatic reactions. In the studies of intramolecularly hydrogen bonded Schiff bases, the NMR spectroscopy is widely used and allows detection of the presence of proton transfer equilibrium and determination of the mole fraction of tautomers [21]. Literature gives a few names of tautomers in equilibrium. The OH-tautomer has been also known as OH-, enol- or imine-form, while NH tautomer as NH-, keto-, enamine-, or proton-transferred form. More detail information concerning the application of NMR spectroscopy for investigation of proton transfer equilibrium in Schiff bases is presented in reviews.42-44... 

In the next pages, a brief overview of known application of NMR spectroscopy for assessing interactions between small molecules and polymers is reported with the aim of underlying the importance of NMR in this research area. 

Heidemann D (1994) In Colombet P, Grimmer AR (eds) Application of NMR spectroscopy to cement science. Gordon and Breach Science, Reading, p 77... 

In respect of radiation effects in polymers, the primary application of NMR spectroscopy is in chemical analysis to determine the changes in chemical structure which may occur on exposure. 

Silverstein, R.M. and G.C. Basler, Spectrometric Identification of Organic Compounds, New York Wiley, 1968. Jackman, L.M. and S. Stemhell, Applications of NMR Spectroscopy in Organic Chemistry, London, Pergamon Press, 1969. 

In this review, chemical shifts and coupling constants of simple dienes will first be summarized, and the theory of chemical shift for dienes and polyenes will then be reviewed. Finally, the recent applications of NMR spectroscopy to a variety of polyenes and dienes and specific systems (allenes, solitons and fullerenes) will be reviewed. 

Although we have tried to cover the literature on standard data as much as possible, our emphasis have been focused on new developments of application of NMR spectroscopy to dienes and polyenes. Readers who seek more basic data rather than recent advances are advised to consult books and journal articles dealing with this topic. 

The application of NMR spectroscopy to the study of the conformational structure of chromatographic stationary phases over the past 25 years is the topic of several reviews [145-147], The commonly measured nuclei of the stationary-phase are... 

A particularly important application of NMR spectroscopy is the structural characterisation of polymers. While initial attempts were made using NMR, the wide... 

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