Nitrogen-15 Magnetic Resonance Research Articles

Subsecond Three-Dimensional Nitrogen-15 Magnetic Resonance Imaging Facilitated by Parahydrogen-Based Hyperpolarization.

Magnetic resonance imaging (MRI) provides unique information about the internal structure and function of living organisms in a non-invasive way. The use of conventional proton MRI for the observation of real-time metabolism is hampered by the dominant signals of water and fat, which are abundant in living organisms. Heteronuclear MRI in conjunction with the hyperpolarization methods does not encounter this issue. In this work, we polarized 15N nuclei of [15N1]fampridine (a drug used for the treatment of multiple sclerosis) to the level of 4% in nuclear magnetic resonance (NMR) experiments and 0.7% in MRI studies using spin-lock-induced crossing combined with signal amplification by reversible exchange. Consequently, three-dimensional 15N MRI of the hyperpolarized 15N-labeled drug was acquired in 0.1 s with a signal-to-noise ratio of 70. In addition, the NMR signal enhancements for 15N-enriched fampridine and fampridine with a natural abundance of 15N nuclei were compared and an explanation for their difference was proposed.

Systematic series of azacycl[3.3.3]azines of varying nitrogen content: Nitrogen-15 magnetic resonance spectra

Nitrogen-15 NMR spectra were obtained for a systematic series of azacycl[3.3.3]azines: 1,3,4,6,7,9-hexaaza-,1,3,4,6,7-pentaaza-,1,3,4,6-tetraaza-, 1,3,4,6,8-pentaaza-, and 1,3,6-triazacycl[3.3.3]azine. The magnetic resonance data were compared with other physical and spectroscopic properties available for the series relative to the diminishing number of peripheral nitrogens in alternating positions. The properties of 1,3,4,6,8-pentaazacycl[3.3.3]azine, which has a peripheral 1,4-diazine-type nitrogen, are distinct from those of the rest of the series.

Phosphorus-31, nitrogen-15, and nitrogen-14 nuclear magnetic resonance spectra of α-tetraphosphorus trisulphide isothiocyanates

Phosphorus-31 n.m.r. spectra of α-P4S3(NCS)2(1), α-P4S3(NCS)Cl (2), and α-P4S3(NCS)I (3) have been measured both for natural-abundance 14N isotopomers [(1a), (2a), and (3a)] and completely 15N-containing isotopomers [(1b), (2b), and (3b)] over a range of temperatures. Assignment and computer fitting of spectra of the 15N compounds has yielded accurate values of 31P–31P and 31P–15N coupling constants, and has allowed their variation with temperature to be studied. Measurement of 15N n.m.r. spectra [compounds (1b) and (3b)] has allowed the signs of the31P–15N couplings to be confirmed. A 14N T1 relaxation study of α-P4S3(14NCS)2(1a) showed a normal relaxation rate, and abnormal broadening in the 31P n.m.r. spectra of the 14N compounds was ascribed instead to the influence of abnormally large 1JPN coupling constants in the scalar coupling relaxation mechanism. Large 31P–15N coupling constants are reported for phosphorus(III) isothiocyanates, and for α-P4S3 derivatives. Similarly, large values of 1J(31P–13C) for α-P4S3(13CN)(12CN), and of the secondary isotope shifts 1Δ[31P(37/35Cl)] for α-P4S3(15NCS)Cl (2b) and α-P4S3Cl2, are reported.

ChemInform Abstract: A COMPARATIVE MULTINUCLEAR PROTON, CARBON‐13, AND NITROGEN‐15 MAGNETIC RESONANCE STUDY OF ORGANIC THIOCYANATES AND ISOTHIOCYANATES

Chemischer InformationsdienstVolume 16, Issue 24 Physical Organic Chemistry ChemInform Abstract: A COMPARATIVE MULTINUCLEAR PROTON, CARBON-13, AND NITROGEN-15 MAGNETIC RESONANCE STUDY OF ORGANIC THIOCYANATES AND ISOTHIOCYANATES M. GIFFARD, M. GIFFARDSearch for more papers by this authorJ. COUSSEAU, J. COUSSEAUSearch for more papers by this authorG. J. MARTIN, G. J. MARTINSearch for more papers by this author M. GIFFARD, M. GIFFARDSearch for more papers by this authorJ. COUSSEAU, J. COUSSEAUSearch for more papers by this authorG. J. MARTIN, G. J. MARTINSearch for more papers by this author First published: June 18, 1985 https://doi.org/10.1002/chin.198524046AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume16, Issue24June 18, 1985 RelatedInformation

Nitrogen-14 Magnetic Resonance Studies of the Exchange of Solvent Pyridine on Bis(β-diketonato)bis(pyridine)nickel(II) and -cobalt(II) Complexes

Abstract The analysis of linewidth and shift data of the nitrogen-14 magnetic resonance gave the following activation parameters for the exchange reaction of pyridine (py) on CoA2(py)2 (A=acac, tfa, and tta) and Ni(acac)2(py)2 with a pyridine molecule as bulk solvent: ΔH\eweq=41.4, 51.1, 48.3, and 47.2 kJ mol−1, ΔS\eweq=18, 17, 3, and 10 JK−1 mol−1, and k1 (298K)=2.9×106, 5.3×104, 2.9×104, and 1.3×105 s−1. Here acac=acetylacetonate, tfa=trifluoroacetylacetonate and tta=thenoyltrifluoroacetonate. The electron-withdrawing power of substituent groups on the β-diketonate rings was correlated with more favorable activation of the exchange, that is, the stronger electron withdrawal causes less dissociative activation. This explains qualitatively even the negative ΔS\eweq values observed for similar pyridine exchange in the cases of Co(hfa)2(py)2 (hfa=hexafluoroacetylacetonate) and Ni(tta)2(py)2.

The exchange of pyridine on bis-pyridine adducts of square-planar nickel(II) complexes containing dithiocarbamate, xanthate, dithiophosphate and monothioacetylacetonate ligands. A nitrogen-14 magnetic resonance study

14N n.m.r. has been used to measure the rates of pyridine exchange of a series of bis pyridine adducts of square-planar nickel(II) complexes containing dithiocarbamate, xanthate, dithiophosphate and monothioacetylacetonate ligands. Substantial variations in the lability of the coordinated pyridine are observed, k,, at 298 K varying from about 103 to 107 s-1. In the monothioacetylacetonate series the lability of pyridine decreases as the electron withdrawing power of the substituents increases. Both the lability and the sensitivity to substituent effects are greater than for the analogous acetylacetonate derivatives. The relationship between the intrinsic Lewis acidity of the nickel(II) centre in the parent square-planar complexes as measured by equilibrium constants for bis pyridine adduct formation and the lability of pyridine in the adducts is explored.

Nitrogen-14 magnetic resonance studies of the effect of pressure on the exchange of ammonia in aqueous nickel(II) ammonia solutions

Nitrogen-14 magnetic resonance studies of the effect of pressure on the exchange of ammonia in aqueous nickel(II) ammonia solutions

ChemInform Abstract: NITROGEN‐14 MAGNETIC RESONANCE STUDIES OF THE EFFECT OF PRESSURE AND TEMPERATURE ON THE RATE OF EXCHANGE OF ACETONITRILE SOLVENT ON IRON(II) AND MANGANESE(II) PERCHLORATES

Chemischer InformationsdienstVolume 13, Issue 24 Organoelement Compounds ChemInform Abstract: NITROGEN-14 MAGNETIC RESONANCE STUDIES OF THE EFFECT OF PRESSURE AND TEMPERATURE ON THE RATE OF EXCHANGE OF ACETONITRILE SOLVENT ON IRON(II) AND MANGANESE(II) PERCHLORATES M. J. SISLEY, Search for more papers by this authorY. YANO, Search for more papers by this authorT. W. SWADDLE, Search for more papers by this author M. J. SISLEY, Search for more papers by this authorY. YANO, Search for more papers by this authorT. W. SWADDLE, Search for more papers by this author First published: June 15, 1982 https://doi.org/10.1002/chin.198224296AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume13, Issue24June 15, 1982 RelatedInformation

Nitrogen-14 magnetic resonance studies of the effect of pressure and temperature on the rate of exchange of acetonitrile solvent on iron(II) and manganese(II) perchlorates

Nitrogen-14 magnetic resonance studies of the effect of pressure and temperature on the rate of exchange of acetonitrile solvent on iron(II) and manganese(II) perchlorates

ChemInform Abstract: NITROGEN‐14 MAGNETIC RESONANCE STUDIES OF THE EFFECT OF PRESSURE ON THE EXCHANGE OF ACETONITRILE SOLVENT ON NICKEL(II) AND COBALT(II)

Chemischer InformationsdienstVolume 12, Issue 5 Physical Organic Chemistry ChemInform Abstract: NITROGEN-14 MAGNETIC RESONANCE STUDIES OF THE EFFECT OF PRESSURE ON THE EXCHANGE OF ACETONITRILE SOLVENT ON NICKEL(II) AND COBALT(II) Y. YANO, Y. YANOSearch for more papers by this authorM. T. FAIRHURST, M. T. FAIRHURSTSearch for more papers by this authorT. W. SWADDLE, T. W. SWADDLESearch for more papers by this author Y. YANO, Y. YANOSearch for more papers by this authorM. T. FAIRHURST, M. T. FAIRHURSTSearch for more papers by this authorT. W. SWADDLE, T. W. SWADDLESearch for more papers by this author First published: February 3, 1981 https://doi.org/10.1002/chin.198105075AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume12, Issue5February 3, 1981 RelatedInformation

Nitrogen-14 magnetic resonance studies of the effect of pressure on the exchange of acetonitrile solvent on nickel(II) and cobalt(II)

Nitrogen-14 magnetic resonance studies of the effect of pressure on the exchange of acetonitrile solvent on nickel(II) and cobalt(II)

Nitrogen-15 magnetic resonance spectroscopy. Natural-abundance spectra of isomeric homooligopeptides of L-norvaline and L-valine to the tetramers

The ^(15)N NMR shifts of chemically and optically pure N- and C-protected homooligopeptides derived from L-norvaline and L-valine to the tetramers have been determined at the natural-abundance level of ^(15)N by using the Fourier-transform technique. The shift effects produced by increasing the chain length and temperature, as well as changing the solvent from a hydrogen-bonding donor to a hydrogen-bonding acceptor and replacing the linear side chain (as in the norvaline peptides) by a β branched side chain (as in the valine peptides), are discussed.

ChemInform Abstract: NITROGEN‐15 MAGNETIC RESONANCE SPECTROSCOPY. NATURAL‐ABUNDANCE SPECTRA OF SECONDARY AMIDES

Chemischer InformationsdienstVolume 9, Issue 34 Physical Organic Chemistry ChemInform Abstract: NITROGEN-15 MAGNETIC RESONANCE SPECTROSCOPY. NATURAL-ABUNDANCE SPECTRA OF SECONDARY AMIDES P. W. WESTERMAN, P. W. WESTERMANSearch for more papers by this authorJ. D. ROBERTS, J. D. ROBERTSSearch for more papers by this author P. W. WESTERMAN, P. W. WESTERMANSearch for more papers by this authorJ. D. ROBERTS, J. D. ROBERTSSearch for more papers by this author First published: August 22, 1978 https://doi.org/10.1002/chin.197834058Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume9, Issue34August 22, 1978 RelatedInformation

Nitrogen-15 magnetic resonance spectroscopy. Natural-abundance spectra of secondary amides

The ^(15)N chemical shifts of 17 N-alkyl- and N-arylethanamides have been determined at the natural-abundance level of ^(15)N using Fourier-transform methods. The shift effects produced by several substituent groups are compared with corresponding substituent effects in amino acids, amino acid derivatives, and dipeptides. The results show that N-alkylethanamides are not especially good models for predicting ^(15)N shifts in dipeptides. The sensitivity of the ^(15)N shift of N-arylethanamides to electronic effects, as reflected in the Hammett p constant, is less than that of the ^(15)N shift in para-substituted benzenamines.

Nitrogen-15 magnetic resonance spectroscopy. Effect of paramagnetic relaxation reagents on the 15N chemical shifts of pyridines

The acetylacetonate complexes of chromium and iron, used as paramagnetic relaxation reagents to shorten the T 1 values of methylpyridine 15N nuclei, appear to affect the chemical shifts to an extent comparable to the substituent effects. The effect is attributed largely to changes in bulk paramagnetic susceptibility when the chemical shifts are measured with respect to an external reference, hence are eliminated by using an internal reference and an external lock. At higher concentrations of the transition metal complex, specific interactions with components of the solution probably play a role.

Nitrogen-15 magnetic resonance spectroscopy. Natural-abundance nitrogen-15 spectra of some 2-amino-2-deoxy-D-hexose derivatives.

The nitrogen-15 nuclear magnetic resonance spectra of some 2-amino-2-deoxj D-hexose drochlorides and 2-acetamido-2-deoxy-D-hexoses and N-benzoyl-D-glucosamine are reported. The differences in chemical shifts for the various hexopyranose structures are discussed in terms of steric, stereoelectronic, and hydrogen-bonding effects. These model compounds were used to study substituent effects related to amino sugar containing polysaccharides and antibiotics.

Nitrogen-15 magnetic resonance spectroscopy. Applicability of nitromethane as an internal chemical shift reference

The 15N resonance position of nitromethane is influenced over a narrow range by choice of solvent, and nitromethane as solvent affects the resonance positions of a variety of nitrogen compounds. Limitations are hence imposed on the use of this substance as a chemical shift standard. Nitromethane 15N signals can be obtained within reasonable periods of time both with and without added paramagnetic complexes, making the material practically useful under both types of measurement conditions.

Nitrogen-15 magnetic resonance of glycine

Nitrogen-15 magnetic resonance of glycine

Effect of magnesium coordination on the carbon-13 and nitrogen-15 magnetic resonance spectra of chlorophyll a. Relative energies of nitrogen n.pi.* states as deduced from a complete assignment of chemical shifts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffect of magnesium coordination on the carbon-13 and nitrogen-15 magnetic resonance spectra of chlorophyll a. Relative energies of nitrogen n.pi.* states as deduced from a complete assignment of chemical shiftsS. G. Boxer, G. L. Closs, and J. J. KatzCite this: J. Am. Chem. Soc. 1974, 96, 22, 7058–7066Publication Date (Print):October 1, 1974Publication History Published online1 May 2002Published inissue 1 October 1974https://doi.org/10.1021/ja00829a038RIGHTS & PERMISSIONSArticle Views315Altmetric-Citations79LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Lability of coordinated acetonitrile in nickel(II) complexes. Nitrogen-14 magnetic resonance study

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLability of coordinated acetonitrile in nickel(II) complexes. Nitrogen-14 magnetic resonance studyStephen F. Lincoln and Robert John WestCite this: J. Am. Chem. Soc. 1974, 96, 2, 400–404Publication Date (Print):January 1, 1974Publication History Published online1 May 2002Published inissue 1 January 1974https://doi.org/10.1021/ja00809a013RIGHTS & PERMISSIONSArticle Views108Altmetric-Citations15LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (573 KB) Get e-Alerts Get e-Alerts