Amine magnetic resonance studies

The 15N magnetic resonance studies of the pyrimidine bases or their derivatives are scarce. Roberts et al.BB have measured the 1H and 15N magnetic resonance spectra of a number of pyrimidines including uracil and 1-methylcytosine. The most important result of this study was the elucidation of the dominant tautomeric structures of uracil and proto-nated 1-methylcytosine as the diketo, 32, and keto-amine form, 7, respectively (cf. Sections II and IV and the spectrum of 1-methylcytosine hydrochloride labeled only in the amino group62). In the case of uracil,85 the two 15N-bonded protons gave two doublets centered at 10.78 and 10.96 ppm (measured downfield from internal tetramethyl-... 

Further evidence for the relatively weakly basic character of th j aziridme nitrogen atom wae provided by a proton magnetic resonance study of a series of cyolic amines,1 1 and measurements of the basicity of cyclic and branched amines toward the Lewis acid trimethylboron. ... 

Merlic, CA. and Adams, B. (1992) Molybdenum-95 nuclear magnetic resonance studies on molybdenum carbonyl complexes of isonitriles and amines./. Organomet. Chem., 431, 313-325. 

N. J. Greenfeld, M. Hussain and J. Lenard (1987). Effect of growth state and amines on cytoplasm and vacuolar pH, phosphate and polyphosphate levels in Saccharomyces cerevisiae a 31P nuclear magnetic resonance study. Biochim. Biophys. Acta, 926, 205-214. 

Adcock, W. Abeywickrema, A. N. Substituent effects in the bicyclo[2.2.2]octane ring system. A carbon-13 and fluorine-19 nuclear magnetic resonance study of 4-substituted bicyclo[2.2.2]oct-l-yl fluorides, / Org. Chem 1982,47,2957-2966. Laube, T Ha, T. K. Detection of hyperconjugative effects in expaimentaUy dete-mined structures of neutral molecules, J. Am. Chem. Soc. 1988,110, 5511-5517. Rozeboom, M. D. Houk, K. N. Stereospecific alkyl group effects on amine lone-pair ionization potentials Photoelectron spectra of alkylpiperidines, / Am Chem Soc. 1982,104,1189-1191. 

Knowles, P. F., Lowe, D. J., Peters, J., Thomeley, R. N. F., and Yadav, K. D. S., 1983, Kinetic and magnetic resonance studies on amine oxidases, in iThe Coordination Chemistry of Metallo-Enzymesi Edited by Bertini, I., Drago, R. S., and Luchinat, C. Reidel publishers, 159nl76. 

Magnetic Resonance Studies of Polytertiary Amine Chelated Alkali Metal Compounds... 

Rekharsky MV, Mayhew MP, Goldberg RN, Ross PD, Yamashoji Y, Inoue Y, A Thermodynamic and nuclear magnetic resonance study of the reaction of a- and y -cyclodextrin with acids, aliphatic amines, and cyclic alcohols, J. Phys. Chem. B 1997 101 87-100. 

Wtmg Y, Guo X., Greenbaum S., liu J., Amine K. Solid Electrolyte Interphase Formation on Lithium-Ion Electrodes A Li Nuclear Magnetic Resonance Study, Electrochem. Solid State Lett. 2001,4, A68-A70. 

Nuclear magnetic resonance studies were also made of Schiff bases obtained from amines and aliphatic /9-diketones. These compounds can exist in any of three tautomeric forms, the keto-imine (10), the keto-enamine (11) and the enol-imine (12) . It was found that in... 

J.E. Sarneski, H.L. Surprenant, F.K. Molen, Ch.N. Reilley, Chemical shifts and protonation shifts in carbon-13 nuclear magnetic resonance studies of aqueous amines, Anal. Chem. 1975,47, 2116. 

Slejko, F.L., Drago, R.S. and Brown, D.G. (1972) Failure of some commonly accepted spectroscopic-enthalpy correlations for chloroform adducts. J. Am. Chem. Soc., 94,9210-9216. Wong, K.F. and Ng, S. (1975) Nuclear magnetic resonance study of the hydrogen bonding of chloroform with aliphatic tertiary amines and ethers. J. Chem. Soc., Faraday Tram. II, 71, 622-630. 

In humans, the focus has been on pretreatment and posttreatment changes in platelets, lymphocytes, and amine metabolites in the body fluids of depressed patients (17). Although direct studies have not been possible, magnetic resonance spectroscopy allows for the noninvasive study of neurochemical changes in the human brain associated with depression and recovery, including investigations of the mechanism of action of ECT ( 18). 

In this Sect, we describe the starting material impurities and their effect on the processing and cure reactions of TGDDM-DDS epoxies. The cure reactions are characterized by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) studies. The BF3 amine catalysts used to accelerate the cure of TGDDM-DDS epoxies are characterized by nuclear magnetic resonance (NMR) spectroscopy studies. 

Abstract—The nature of the product of the reaction between an aminated silane and carbon dioxide was re-examined with the aid of simple model compounds, several amines, and several aminosilanes. Since the reaction products previously proposed include the amine bicarbonate and a carbamate derived from the amine, ammonium bicarbonate and ammonium carbamate were studied as models for the anions. Carbon dioxide adducts of neat model amines were prepared and studied. Results from a variety of techniques are summarized. Among the most useful was Fourier transform infrared (FTIR) spectroscopy of fluorolube mulls. FTIR spectra were distinctive and assignments characteristic of the two species were extracted from the spectral data. Comparisons of these assignments with the products of the reaction between carbon dioxide and various amines were made. The results indicate that alkylammonium carbamates are the principal product. Nuclear magnetic resonance (NMR) spectra in D20 indicated much dissociation and were not helpful in defining the products. 

Evidence for the interaction between tributylamine and BN nanotubes has been obtained by nuclear magnetic resonance spectroscopy. We have studied the H and 13C NMR spectra of tributylamine-functionalized BN nanotubes in comparison with the spectra of tributylamine. We observe a small increase in the H chemical shift by 0.02 ppm in the amine-BN adduct. In the case of nC NMR spectra, we observe a significant increase in the chemical shifts of the y and S carbons by 0.4 ppm and a decrease in the chemical shift of the P carbon atom by 0.3 ppm. The chemical shift of the acarbon is also higher in the amine-BN adduct by 0.1 ppm. The changes in the H and L1C spectra of tributylamine found on interaction with BN are comparable to those reported in the literature for similar complexes.17,18... 

Measuring the acidity of the Bronsted and Lewis acid sites is problematic. The adsorption and desorption of various amines has been used, but there is some disagreement about what it means.160 Some workers prefer to use isopropylamine, which desorbs only from Bronsted sites. Solid-state nuclear magnetic resonance (NMR) has also been used in the study of reactions on zeolites.161 Many zeolites crystallize into crystals that are too fine for conventional X-ray analysis. A new method that uses synchrotron X rays on microcrystalline powders promises to make it much easier to determine the structures of zeolites and related materials.162... 

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