Nuclear magnetic resonance spectroscopy complexes

We saw in Chapter 12 that mass spectrometry gives a molecule s formula and infrared spectroscopy identifies a molecule s functional groups. Nuclear magnetic resonance spectroscopy does not replace either of these techniques rather, it complements them by "mapping" a molecule s carbon-hydrogen framework. Taken together, mass spectrometry, JR, and NMR make it possible to determine the structures of even very complex molecules. 

Theng BKG, Newman RH, Whitton JS (1998) Characterization of an alkylammonium-montmorillonite-phenanthrene intercalation complex by carbon-13 nuclear magnetic resonance spectroscopy. Clay Miner 33 221-229... 

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. 

Keywords High-pressure studies Magnetic susceptibility Mossbauer and Nuclear Magnetic Resonance spectroscopy Pyrazolylborate complexes Pyrazolylmethane complexes... 

Bilia, A. R., Bergonzi, M. C., Mazzi, G., and Vincieri, F. F. (2001). Analysis of plant complex matrices by use of nuclear magnetic resonance spectroscopy St. John s wort extract. /. Agric. Food Chem. 49, 2115-2124. 

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... 

Nuclear magnetic resonance spectroscopy is the most powerful technique for the determination of the structure of intermolecular complexes in solution... 

Hunger and Wang provide an account of advances in the characterization of solid catalysts in the functioning state by nuclear magnetic resonance spectroscopy. Examples include investigations of zeolite-catalyzed reactions with isotopic labels that allow characterization of transition states and reaction pathways as well as characterization of organic deposits, surface complexes, and reaction intermediates formed in catalyst pores. 

The spectral properties of ethylene oxides are among the most important, not only for the information derivable from them concerning tbe intimate structure of the three-merabered oxide ring, but also in connexion with the detection and identification of this function in complex molecules of unknown constitution, e.g. natural product. The present review is concerned with the following three types of gpectroBoopy A) infrared spectroscopy, ( ) ultraviolet spectroscopy, and ( 7) nuclear magnetic resonance spectroscopy,... 

The coupling of LC (liquid chromatography) with NMR (nuclear magnetic resonance) spectroscopy can be considered now to be a standard analytical technique. Today, even more complex systems, which also include mass spectrometry (MS), are used. The question arises as to how such systems are handled efficiently with an increasing cost and a decreasing availability of skilled personal. LC-NMR and LC-NMR/MS combine the well-established techniques of LC, NMR and MS. For each of those techniques, various automation procedures and software packages are available and used in analytical laboratories. However, due to the necessary interfacing of such techniques, completely new demands occur and additional problems have to overcome. 

Wheat starch lysophospholipid forms tiny liposomes in water that could readily be transported into the interior of a starch granule during its development. Solid-state nuclear magnetic resonance spectroscopy suggests that the phospholipids in wheat starch are predominantly complexed with amylose in an amorphous form in the granules.354-356... 

Amazaki TY, Hinck AP, Wang XY, Nicholson LK, Torchia DA, Wingfield P, Stahl SJ, Kaufman JD, Chang CH, Domaille PJ, Lam PY, Three-dimensional solution structure of the HIV-1 protease complexed with DMP323, a novel cyclic urea-type inhibitor, determined by nuclear magnetic resonance spectroscopy, Protein Sci., 5 495-506, 1996. 

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