Nuclear Spin Coupling Research Articles

Phosphorus–phosphorus nuclear spin coupling in tetraorganobiphosphines and some of their derivatives

The signs and magnitudes of 31P–31P and 31P–H spin-coupling constants in tetraorganobiphosphines RR′PPRR′ with Me, Ph, and/or But as substituents, and in their sulphides and selenides RR′P(X)P(X)RR′(X = S or Se), have been determined by 1H-{31P} heteronuclear double resonance. Large variations in 1J(31P-31P) arise as a result of changes in the phosphorus hybridization and/or effective nuclear charge, and smaller variations as a result of changes in the position of rotameric equilibrium in the gauche conformers of the biphosphines.

Nitrogen-15 nuclear magnetic resonance of organophosphorus compounds. Ring size and aziridine methylation effects on nitrogen-15 shifts and nitrogen-15-phosphorus-31 nuclear spin couplings in heterocyclic phosphoramidates

Nitrogen-15 nuclear magnetic resonance of organophosphorus compounds. Ring size and aziridine methylation effects on nitrogen-15 shifts and nitrogen-15-phosphorus-31 nuclear spin couplings in heterocyclic phosphoramidates

Second-order effects of magnetic hyperfine interaction on NMR spectra in theM2CuX4·2H2Ocompounds. II. Fine structure due to indirect coupling of nuclear spins

Second-order effects of magnetic hyperfine interaction on NMR spectra in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>M</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi><mml:mrow><mml:msub><mml:mrow><mml:mi>X</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mi>·</mml:mi><mml:mn>2</mml:mn><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:math>compounds. II. Fine structure due to indirect coupling of nuclear spins

Carbon-13 nuclear magnetic resonance studies of (Z)-5-fluoro-2-methyl-1-{[p-(methylsulfinyl)phenyl] methylene}-1H-indene-3-acetic acid (sulindac) and some related compounds

Carbon-13 nuclear magnetic resonance spectra have been obtained and fully assignee for a number of 2-methyl-1-{[p-(methylthio) or -(methylsulfinyl}phenyl]methylene}-1H-indene-3- acetic acid derivatives, including the potent anti-inflammatory compound sulindac, 1Z. Paired E and Z isomers were studied along with the sulindac sodium salt and ethyl ester in the Z series. Variations in steric crowding in E vs. Z isomers produce chemical shift effects which alternate with the number of intervening bonds. Fluorine substituent effects and 19F nuclear spin coupling to 13C nuclei, second-order features in off-resonance proton-decoupled spectra, and values of long-range 13CH nuclear spin coupling constants have been employed in making a complete set of assignments.

Stereochemical analysis of aromatic oximes. 13C–15N nuclear spin coupling and 13C shieldings as conformational probes

13C nmr chemical shifts and 13C–15N spin couplings over one, two, and three bonds are reported for six aromatic oximes including two benz annelated compounds. Preferred geometries have been calculated via the GEMO program. Fermi contact contributions to carbon–nitrogen coupling have been evaluated and, in general, agreement between experimental and theoretical values is poor. Vicinal 13C–15N couplings are shown to depend on both dihedral angle and oxime valence angle. Oxime carbon chemical shifts do not provide a measure of deviation from planarity between the oxime group and the aromatic ring.The sign of 1JCN in E-benzaldoxime has been determined to be negative.

Oxygen-17 nuclear magnetic resonance spectroscopy: spin coupling to phosphorus-31

The one-bond reduced nuclear spin coupling 1K(PO) is shown by 1H–{17O} INDOR experiments to be negative in (MeO)3P and in (MeO)2PHO.

Calculation of the nuclear spin coupling constant by a variational procedure on a finite part of the second-order perturbed energy

The nuclear spin-spin coupling constant of H-D molecule is calculated using ab initio LCAO MO SCF method using extended basis sets with and without configuration interaction. The essential feature of this calculation is that the delta function arising from the Fermi contact operator is removed by transformation. The perturbation variation theory, then, leads to a minimization of a finite part of the second order energy and a better convergence of the value of the coupling constant is expected. Calculations show that this convergence is improved by the transformation used. Moreover we show that the coupling constants are not very sensitive to the exact behavior of the contact operator near the nucleus provided that these operators are proportional to r N −2 near the nuclei.

ChemInform Abstract: STUDIES OF PHOSPHORUS‐PHOSPHORUS NUCLEAR‐SPIN COUPLING IN SPECIES WITH PHOSPHORUS‐NITROGEN BONDS

Chemischer InformationsdienstVolume 8, Issue 49 Physical Organic Chemistry ChemInform Abstract: STUDIES OF PHOSPHORUS-PHOSPHORUS NUCLEAR-SPIN COUPLING IN SPECIES WITH PHOSPHORUS-NITROGEN BONDS I. J. COLQUHOUN, I. J. COLQUHOUNSearch for more papers by this authorW. MCFARLANE, W. MCFARLANESearch for more papers by this author I. J. COLQUHOUN, I. J. COLQUHOUNSearch for more papers by this authorW. MCFARLANE, W. MCFARLANESearch for more papers by this author First published: December 6, 1977 https://doi.org/10.1002/chin.197749056AboutPDF 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. Volume8, Issue49December 6, 1977 RelatedInformation

Carbon‐13 n.m.r. of the 8‐phosphabicyclo[3.2.1]octane system

Abstract13C Chemical shifts and 13C31P nuclear spin coupling constants have been determined for 26 8‐phosphabicyclo[3.2.1]octane derivatives, namely phosphines, phosphine oxides, phosphine sulphides and one phosphonium salt. The influence of the phosphorus configuration on δ and 2J(PC) values was examined and other factors influencing the 2J(PC) coupling constant are discussed.

Nitrogen-15 and oxygen-17 nuclear magnetic resonance of organophosphorus compounds. Experimental and theoretical determinations of nitrogen-15-phosphorus-31 and oxygen-17-phosphorus-31 nuclear spin coupling constants

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNitrogen-15 and oxygen-17 nuclear magnetic resonance of organophosphorus compounds. Experimental and theoretical determinations of nitrogen-15-phosphorus-31 and oxygen-17-phosphorus-31 nuclear spin coupling constantsGeorge A. Gray and Thomas A. AlbrightCite this: J. Am. Chem. Soc. 1977, 99, 10, 3243–3250Publication Date (Print):May 1, 1977Publication History Published online1 May 2002Published inissue 1 May 1977https://doi.org/10.1021/ja00452a007RIGHTS & PERMISSIONSArticle Views110Altmetric-Citations54LEARN 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 (866 KB) Get e-Alerts Get e-Alerts

Studies of phosphorus–phosphorus nuclear-spin coupling in species with phosphorus–nitrogen bonds

1 H-{31P} double-resonance experiments have been used to study 34 organophosphorus spacies with a P–N–P skeleton. The geminal 31P–31P coupling constant is large and positive in derivatives of three-co-ordinate phos-phorus and is increased by bulky or electronegative substituents on phosphorus. The results for several pairs of diastereoisomers, and also the temperature dependence, indicate a strong conformational dependence of the coupling which is related to the relative orientation of the lone pairs on phosphorus. In spacies with at least one four-coordinate phosphorus atom this last feature is absent, and the coupling constant is much smaller.

Theoretical calculations of nuclear spin coupling of phosphorus to carbon and hydrogen by the finite perturbation method

AbstractFinite perturbation calculations using CNDO/2 wave functions are presented for the determination of 31P13C and 31P1H couplings. The calculations were carried out on 46 molecules and a comparison with experimental values is given. The groups of compounds considered were phosphonium cations, phosphine oxides, alkylidenephosphoranes, phosphine sulfides, phosphoranes and phosphines. With the exception of phosphines, the finite perturbation approach reproduces the experimental couplings with fair accuracy. It is found that there is a good correlation with the calculated 1J(P, C) and the phosphorus 3s‐carbon 2s bond orders for tetra‐ and pentavalent phosphorus compounds. This lends support to the growing body of evidence for the direct relationship of the magnitude of 1J(P, C) and percent s character in the hybrid orbital on the carbon comprising the PC bond. The finite perturbation technique was also used to explore the effects of geometrical changes on PC and PH couplings. Finally, the effect of deleting d orbitals on phosphorus is discussed briefly.

Self-consistent molecular orbital calculations of nuclear spin coupling constants in organosilicon compounds; trimethylsilyl systems

Finite perturbation calculations of carbon-silicon nuclear spin coupling constants in trimethylsilyl compounds have been carried out using an INDO scheme extended to the second row. Generally good agreement with experimental values is noted. Correlations between coupling constants and certain parameters related to hybridization and electron distribution are discussed.

The calculation of nuclear spin coupling constants from LCAO–SCF–Xα wavefunctions

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Nitrogen-15 nuclear magnetic resonance of organophosphorus compounds. Experimental determination and SCF-MO finite perturbation calculation of nitrogen-15-phosphorus-31 nuclear spin coupling constants in tris(dimethylamino)phosphine, -phosphine sulfide, and -phosphine oxide

Nitrogen-15 nuclear magnetic resonance of organophosphorus compounds. Experimental determination and SCF-MO finite perturbation calculation of nitrogen-15-phosphorus-31 nuclear spin coupling constants in tris(dimethylamino)phosphine, -phosphine sulfide, and -phosphine oxide

Die metall-kohlenstoff-bindung in carben- und carbin-komplexen. aussagen der 183W 13C-kopplungen

The nuclear spin coupling constants 1 J( 183W 13C) and in some cases 2 J( 183W 13C) and 3 J( 183W 13C) are determined for 10 tungsten carbene and 9 tungsten carbyne complexes. 1 J is of analytical importance, being characteristically greater for WC than for WC bonds. This is due to different hybridisation at the carbon atom, and provides information about bond angles and polarities of WC and WCR units. Substituents R and R' in (CO) 5WCRR' and X(CO) 4WCR as well as the halogens X lead to minor changes in 1 J. These changes are comparable to those of 1 J( 13C 1H) in correspondingly substituted methanes. Unexpectedly 1 J in_ creases with X = Cl, Br, I. 2 J( 183W 13C) though being much smaller than 1 J reflects different hydridisation at the β carbon atom.

The signs of nuclear spin coupling constants in some trifluoromethyl derivatives of platinum and of gold

The signs and magnitudes of 3J(31P ⋯1H), 3J(31P ⋯19F), and other coupling constants have been determined by multiple-resonance methods in methyl and trifluromethyl derivatives of platinum(II), platinum (IV), gold(I), and gold (III). Whilst 3J(31P ⋯1H) is more negative when the coupling path is trans than when it is cis, the converse is true of 3J(31P ⋯19F). The coupling fall into ranges which are sufficiently distinct to permit their diagonistic use, and their origin is discussed in terms of the bonding in the complexes.

Fluorine nuclear spin coupling constants in fluoro-substituted furans

In order to assist experimental assignments in olefinic and aromatic fluorine compounds, fluorine nuclear coupling constants have been obtained from the first-order self-consistent perturbation theory equation with the INDO molecular orbital approximation in a series of fluoro-substituted furans. There is a clear distinction between the magnitudes and signs for the four fluorine coupling positions; the importance of the orbital and spin-dipolar contributions is very clear. Tentative signs are suggested for all the coupling constants.

Thermomagnetic torque in hydrogen isotopes

The thermomagnetic torque has been measured in parahydrogen and ortho and normal deuterium for pressures from 0.10 to 2.0 torr and temperatures from 100 to 370 K. Since the torque depends on the precession of the molecular rotational magnetic moment around the field direction, coupling of the molecular nuclear spin to the rotational moment can affect the torque. Evidence of spin coupling effects is found for the torque in both deuterium modifications. In para hydrogen the torque at all temperatures and pressures exhibits behavior expected of a gas of zero nuclear spin molecules. Additionally, earlier data for hydrogen deuteride and for normal hydrogen from 105 to 374 K are evaluated and discussed. The high pressure limiting values of torque peak heights and positions for all these gases are compared with theory.

Phosphorus-nitrogen nuclear spin coupling in representative organo-phosphorus compounds

Phosphorus-nitrogen nuclear spin coupling in representative organo-phosphorus compounds