Nuclear magnetic resonance multiplets

H. S. Gutowsky, D. W. McCall and C. P. Slichter, Nuclear magnetic resonance multiplets in... 

Something of scientific interest (among numerous other applications, Pascal s triangle is used to predict nuclear magnetic resonance [NMR] multiplet splitting patterns) has been created from the repeated application of a simple rule. 

Nuclear magnetic resonance spectrum (deuteriochloroform-solvent, internal tetramethylsilane reference) multiplet at... 

Spin-spin coupling The interaction between the spin magnetic moments of different electrons and/or nuclei. It causes, e.g. the multiplet pattern in nuclear magnetic resonance spectra. 

The nuclear magnetic resonance (n.m.r.) spectra of aldose dithioacetals dissolved in pyridine-d5 or dimethyl sulfoxide-d6 generally exhibit extensively overlapping multiplets under which most of the sugar-proton resonances lie. Peracetylation of the dithioacetal, how-... 

GMP 5 - guanosine monophosphate, 5 - CMP 5 - cytosine monophosphate. HPLC high - pressure liquid chromatography NMR nuclear magnetic resonance, s = singlet, d doublet, t triplet, q = quartet, m multiplet, NOE nuclear Overhauser effect, CD circular dichroism. tn trimethylene diamine, dien diethylene-triamine. CPK models Corey - Pauling - Koltun atomic models. 

Fig. 8-9. The 11B nuclear magnetic resonance spectrum of Bi0HJ4. The assignment is shown at the top circled numbers give intensities of the multiplets. The inset shows the appearance of a portion of the spectrum of 2-iodo-Bi0Hi3.

The instructor or a laboratory assistant will record the NMR spectrum of the reaction mixture. Submit a sample vial containing the mixture for this spectroscopic determination. The spectrum will also contain integration of the important peaks (Technique 26, "Nuclear Magnetic Resonance Spectroscopy"). Compare the integral of the downfield peaks of the alkyl halide multiplets. The relative heights of these integrals correspond to the relative amounts of each halide in the mixture. 

The following abbreviations are used d = doublet t = triplet q = quartet m = multiplet. Data not obtained by the author are from (a) Levy, G. C. Lichter, R. L. Nelson, G. L. Carbon-13 Nuclear Magnetic Resonance Spectroscopy, 2nd edition, Wiley-Interscience, New York, 1980, and (b) Jackman, L. M. Sternhell, S. Applications of Nuclear Magnetic Resonance Spectroscopy in Organic Chemistry, 2nd edition, Pergamon, Oxford, UK, 1969. 

Lin RC, Davis EJ (1974) Malic enzymes of rabbit heart mitochondria. J Biol Chem 249 3867-3875 London RE, Kollman VH, Matwiyoff NA (1975a) The quantitative analysis of carbon-carbon coupling in the C nuclear magnetic resonance spectra of molecules biosynthesized from " C enriched precusors. J Am Chem Soc 97 3565-3573 London RE, Matwiyoff NA, Kollman VH (1975b) Differential nuclear overhauser enhancement for i C siglet and multiplet resonances of a carboxyl carbon. J Magn Res 18 555-557... 

A measurement method that is often used to determine the C-labeling of metabolites is 2D [ C. H] correlation nuclear magnetic resonance spectroscopy (COSY). This method yields relative intensities of multiplets in the NMR spectra that correspond to the relative amounts of groups of isotopomers in which the observed atom is C-labeled and the adjacent carbon atoms in the carbon backbone are either C-labeled or not (Szyperski, 1995). If the compound of which the labeling pattern is measured was synthesized by a microorganism growing on a mixture of uniformly C-labeled and naturally labeled carbon substrate, then the relative intensities of NMR fine structures can be calculated from the fractions of molecules that stem from one or more substrate molecule(s) in the feed medium. This is done using so-called probability equations (Szyperski, 1995) that require as input the fraction of uniformly C-labeled medium substrate and the fraction of naturally C-labeled carbon. 

FT-NMR,411 homotopic, 419 integration, 423 multiplet, 423 n + 1 rule, 425 nuclear magnetic resonance (NMR) spectroscopy, 404 shielding, 406 spin-spin splitting, 424 upheld, 409... 

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