Quadrupolar interactions in amines as determined by <sup>1</sup>H nuclear magnetic resonance: mono- and dimethylamines

Halliday, James D.; Bindner, P.E.; Padamshi, Shahsultan

doi:10.1139/v84-208

Cited by 8 publications

(4 citation statements)

References 5 publications

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“… a Geometries are optimized MP2/6-31+G(d,p) geometries except where noted; 1 J (C−H) for methyl C−H couplings is the weighted average. b Geometry from ref . c Reference . d Reference . e Reference . f Geometry from ref . g Reference . h Geometry from ref . i Reference . j Reference . k Reference . l Reference . m Reference . n Reference . o Geometry from ref . p Reference . q Reference . …”

Section: Resultsmentioning

confidence: 99%

“…Seventy-one experimentally measured coupling constants − have been reported for the 31 molecules included in this study. These molecules are listed by number in Table , beginning with CH 4 and followed by molecules with C−C single, double, and triple bonds.…”

Section: Resultsmentioning

confidence: 99%

“…SOPPA calculations were performed using Dalton-2 26 on the IQM computers, and the EOM-CCSD calculations were done with ACES II 27 on the Itanium Cluster at the Ohio Supercomputer Center. Seventy-one experimentally measured coupling constants [28][29][30][31][32][33][34][35][36][37][38][39] have been reported for the 31 molecules included in this study. These molecules are listed by number in Table 1, beginning with CH 4 and followed by molecules with C-C single, double, and triple bonds.…”

Section: Methodsmentioning

confidence: 99%

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A Systematic Comparison of Second-Order Polarization Propagator Approximation and Equation-of-Motion Coupled Cluster Singles and Doubles C−C, C−N, N−N, C−H, and N−H Spin−Spin Coupling Constants

2009

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Ab initio one-, two-, and three-bond C-C, C-N, and N-N spin-spin coupling constants, and one-bond C-H and N-H coupling constants have been computed using two different theoretical methods, SOPPA/ (qzp,qz2p) and EOM-CCSD/(qzp,qz2p). Both EOM-CCSD (equation-of-motion coupled cluster singles and doubles) and SOPPA (second-order polarization propagator approximation) coupling constants correlate linearly with experimental data. In the great majority of cases, the computed EOM-CCSD C-C, C-N, N-N, and N-H coupling constants are in better agreement with experimental data than SOPPA values, although both levels of theory provide reasonable estimates of these couplings. EOM-CCSD consistently underestimates one-bond C-H coupling constants by about 10 Hz, and SOPPA values of 1 J(C-H) are in better agreement with experimental data. The performance of SOPPA supports its use in future studies of coupling constants involving C, N, and H in larger chemical and biological systems. † Part of the "Rusell M. Pitzer Festschrift".

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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A Systematic Comparison of Second-Order Polarization Propagator Approximation and Equation-of-Motion Coupled Cluster Singles and Doubles C−C, C−N, N−N, C−H, and N−H Spin−Spin Coupling Constants

2009

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“…spectra of completely anhydrous ammonia, 4,5 ammonium ions in acid solutions, 6 anhydrous dimethylamine, 7 some tetra-alkyl ammonium salts, alkyl isonitriles, trimethyl vinyl ammonium salts, 8 pyrrole 9 and the pyridinium ion 10 in which due to the high symmetry of the electrical gradient at the 14 N nucleus, quadrupolar relaxation is long enough to allow 14 N-1 H coupling to occur. The magnitude of the coupling constant between 14 N and directly bonded hydrogen depends on the hybridisation of the nitrogen and is enhanced with increasing s character of the bond.…”

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confidence: 99%

NMR Evidence for Cationic Behaviour of the Benzotriazole Ring in Novel α-(benzotriazol-1-yl)-N-acylglycines

Khalaj

Pirali

Dowlatabadi

2001

Journal of Chemical Research

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Benzotriazole is a synthetic auxiliary which depending on the nature of the attached groups and the reaction conditions can exist as both cationic or anionic species. 1 In the course of our investigations on the structure-activity relationship of cholecystokinin antagonists, novel acylglycine compounds 1-3 were prepared by condensation of benzotriazole, glyoxylic acid and aromatic amides with the azeotropic removal of water 2 (Scheme 1).The 1 H NMR of these compounds showed a triplet with coupling constant of 51.2 Hz and chemical shift around 7.2 ppm corresponding to one proton which was exchangeable with D 2 O (Fig. 1).Based on these observations it was reasoned that in ([ 2 H 6 ] DMSO) that was used as the solvent for 1 H NMR spectroscopy, acylglycine compounds 1-3 may behave as zwitterions in which the benzotriazole moiety accepts the proton resulting from the ionisation of the carboxyl group (Scheme 1) and the indicating triplet arises from the spin coupling of the 14 N nucleus to a proton.Consistent with our interpretation the triplet resulting from 14 N-1 H spin coupling was absent in 1 H NMR spectrum of the ethyl ester of compound 1 which cannot exist in zwitterionic form.Spin coupling between 14 N and 1 H nuclei is not usually observable because of the rapid quadrupolar relaxation of the 14 N nucleus. 3 However, this pattern of coupling has been reported in ExperimentalMelting points were determined on a Reichert hot plate apparatus and are uncorrected. 1 H and 13 C NMR spectra were recorded on a Varian Unity Plus 400 spectrometer (399.866 MHz for 1 H NMR and 100.556 MHz for 13 C NMR ) using [ 2 H 6 ] DMSO as solvent. Chemical shifts (δ) are reported in p.p.m. related to tetramethyl silane (TMS) as internal

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Solvation of tetraphenylphosphonium dicyanamide

Garbuz¹,

Skopenko²,

Gerasimchuk³

et al. 1988

Theor Exp Chem

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Quadrupolar interactions in amines as determined by ¹H nuclear magnetic resonance: mono- and dimethylamines

Cited by 8 publications

References 5 publications

A Systematic Comparison of Second-Order Polarization Propagator Approximation and Equation-of-Motion Coupled Cluster Singles and Doubles C−C, C−N, N−N, C−H, and N−H Spin−Spin Coupling Constants

A Systematic Comparison of Second-Order Polarization Propagator Approximation and Equation-of-Motion Coupled Cluster Singles and Doubles C−C, C−N, N−N, C−H, and N−H Spin−Spin Coupling Constants

NMR Evidence for Cationic Behaviour of the Benzotriazole Ring in Novel α-(benzotriazol-1-yl)-N-acylglycines

Solvation of tetraphenylphosphonium dicyanamide

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Quadrupolar interactions in amines as determined by 1H nuclear magnetic resonance: mono- and dimethylamines

Cited by 8 publications

References 5 publications

A Systematic Comparison of Second-Order Polarization Propagator Approximation and Equation-of-Motion Coupled Cluster Singles and Doubles C−C, C−N, N−N, C−H, and N−H Spin−Spin Coupling Constants

A Systematic Comparison of Second-Order Polarization Propagator Approximation and Equation-of-Motion Coupled Cluster Singles and Doubles C−C, C−N, N−N, C−H, and N−H Spin−Spin Coupling Constants

NMR Evidence for Cationic Behaviour of the Benzotriazole Ring in Novel α-(benzotriazol-1-yl)-N-acylglycines

Solvation of tetraphenylphosphonium dicyanamide

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Quadrupolar interactions in amines as determined by ¹H nuclear magnetic resonance: mono- and dimethylamines