Nuclear magnetic resonance spectroscopy compounds

Present day techniques for structure determination in carbohydrate chemistry are sub stantially the same as those for any other type of compound The full range of modern instrumental methods including mass spectrometry and infrared and nuclear magnetic resonance spectroscopy is brought to bear on the problem If the unknown substance is crystalline X ray diffraction can provide precise structural information that m the best cases IS equivalent to taking a three dimensional photograph of the molecule... 

Nuclear Magnetic Resonance Spectroscopy of Organofluorine Compounds... 

The presence of iminium salts can be detected by chemical means or by spectroscopic methods. The chemical means of detecting iminium salts are reactions with nucleophiles and are the subject of this review. The spectroscopic methods are more useful for rapid identification because with the large number of model compounds available now the spectroscopic methods are fast and reliable. The two methods that are used primarily are infrared and nuclear magnetic resonance spectroscopy. Some attempts have been made to determine the presence of iminium salts by ultraviolet spectroscopy, but these are not definitive as yet (14,25). 

The tautomerism of 2- and 3-aminothiophenes was mentioned by Hartough in his review of thiophenes/ but the first definite evidence became available in 1961 when Hoffman and Gronowitz showed conclusively by nuclear magnetic resonance spectroscopy that these compounds both exist in the amino form. In agreement with this finding, 3-aminothiophene generally behaves as an aromatic amine. ... 

Determining the structure of an organic compound was a difficult and time-consuming process in the 19th and early 20th centuries, but powerful techniques are now available that greatly simplify the problem. In this and the next chapter, we ll look at four such techniques—mass spectrometry (MS), infrared (IR) spectroscopy, ultraviolet spectroscopy (UV), and nuclear magnetic resonance spectroscopy (NMR)—and we U see the kind of information that can be obtained from each. 

Noth, H., and Wrackmeyer, B. (1978) Nuclear Magnetic Resonance Spectroscopy of Boron Compounds, Springer-Verlag, New York. 

Fluorine compounds-Spectra. 2. Nuclear magnetic resonance spectroscopy. I. Title. QD412.F1D65 2009 547. 02—dc22... 

Laughlin et al. [122] analysed chloroform extracts of tributyltin dissolved in seawater using nuclear magnetic resonance spectroscopy. It was shown that an equilibrium mixture occurs which contains tributyltin chloride, tributyl tin hydroxide, the aquo complex, and a tributyltin carbonate species. Fluorometry has been used to determine triphenyltin compounds in seawater [123]. Triph-enyltin compounds in water at concentrations of 0.004-2 pmg/1 are readily extracted into toluene and can be determined by spectrofluorometric measurements of the triphenyltin-3-hydroxyflavone complex. 

Partington, P., Feeney, J. and Burgen, A. S. V. The conformation of acetylcholine and related compounds in aqueous solutions as studied by nuclear magnetic resonance spectroscopy. Mol. Pharmacol. 8 269-277,1972. 

Non-specific sum parameter analysis [12,13], which is still used today, failed [14,15] in the analyses of some of these compounds. Chromatographic methods in combination with non-substance specific detectors, e.g. colorimetric and photometric [5] or with substance specific detectors such as IR (infrared spectroscopy), NMR (nuclear magnetic resonance spectroscopy) or MS (mass spectrometry), are applied increasingly nowadays. 

H. Noth, B. Wrackmeyer, Nuclear Magnetic Resonance Spectroscopy of Boron Compounds, in NMR - Basic Principles and Progress, P. Diehl, E. Fluck, R. Kosfeld, eds., Vol. 14, Springer Verlag, Berlin-Heidelberg-New York, 1978. 

Hyphenated analytical techniques such as LC-MS, which combines liquid chromatography and mass spectrometry, are well-developed laboratory tools that are widely used in the pharmaceutical industry. Eor some compounds, mass spectrometry alone is insufficient for complete structural elucidation of unknown compounds nuclear magnetic resonance spectroscopy (NMR) can help elucidate the structure of these compounds (see Chapter 20). Traditionally, NMR experiments are performed on more or less pure samples, in which the signals of a single component dominate. Therefore, the structural analysis of individual components of complex mixtures is normally time-consuming and less cost-effective. The... 

Analytical aspects of organolithium compounds 5. Nuclear magnetic resonance spectroscopy and magnetic titrations... 

The hyphenation of capillary electromigration techniques to spectroscopic techniques which, besides the identification, allow the elucidation of the chemical structure of the separated analytes, such as mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR) has been widely pursued in recent years. Such approaches, combining the separation efficiency of capillary electromigration techniques and the information-rich detection capability of either MS or NMR, are emerging as essential diagnostic tools for the analysis of both low molecular weight and macromolecular compounds. 

Nuclear magnetic resonance spectroscopy, 46 161-162, see also specific compounds of alkyne-substituted clusters... 

E. Ackerstaff, B.R. Pfiug, J.B. Nelson, Z.M. Bhujwalla, Detection of increased choline compounds with proton nuclear magnetic resonance spectroscopy subsequent to malignant transformation of human prostatic epithelial cells. Cancer Res. 61(9) (2001) 3599-3603. 

R.L. Frost, R.W. Parker, J.V. Hanna, Detection of the pesticide compound-1080 (sodium monofluoroacetate) using F-19 nuclear magnetic-resonance spectroscopy. Analyst 114 (1989) 1245-1248. 

Kosir, I.J. and Kidric, J., Use of modern nuclear magnetic resonance spectroscopy in wine analysis determination of minor compounds, Anal Chim. Acta, 458, 77, 2002. 

Hodson, J., The Estimation of the Photodegradation of Organic Compounds by Hydroxyl Radical Reaction Rate Constants Obtained from Nuclear Magnetic Resonance Spectroscopy Chemical Shift Data, Chemosphere, 17, 2339-2348 (1988). 

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