ChemInform Abstract: THERMOCHEMISTRY OF FLUOROXY COMPOUNDS: A LINEAR CORRELATION BETWEEN OXYGEN-FLUORINE BOND ENERGIES AND FLUORINE-19 CHEMICAL SHIFTS

1984 ◽  
Vol 15 (25) ◽  
Author(s):  
E. GHIBAUDI ◽  
A. J. COLUSSI
Keyword(s):  
Linear Correlation ◽  
Chemical Shifts ◽  
Bond Energies ◽  
Oxygen Fluorine

A LINEAR CORRELATION OF PROTON CHEMICAL SHIFTS IN SOME ALKYL CHLORIDES AND HYDROCARBONS WITH THE OCCUPATION NUMBER OF THE HYDROGEN ORBITALS

1965 ◽  
Vol 43 (12) ◽  
pp. 3188-3192 ◽  
Author(s):  
F. Hruska ◽  
G. Kotowycz ◽  
T. Schaefer
Keyword(s):  
Linear Correlation ◽  
Occupation Number ◽  
Chemical Shifts ◽  
The Self ◽  
Starting Values ◽  
Occupation Numbers ◽  
Self Consistent ◽  
Consistent Group ◽  
Proton Chemical Shifts ◽  
Group Orbital

A linear correlation exists between the proton shifts of some alkyl chlorides and some hydrocarbons and the occupation numbers of the hydrogen 1s orbitals in the C—H bonds. The occupation numbers are those given by the self-consistent group orbital and bond electronegativity method. The application of this correlation to the prediction of starting values for occupation numbers, to the derivation of bond anisotropies in ethylene and acetylene, and to the prediction of hydrogen-bonded shifts of C—H protons is discussed.

scholarly journals pH-Dependent Piecewise Linear Correlation of 1H,31P Chemical Shifts: Application in NMR Identification of Nerve Agent Metabolites in Urine Samples

2018 ◽  
Vol 90 (14) ◽  
pp. 8495-8500 ◽  
Author(s):  
Harri Koskela ◽  
Boban Andjelkovic ◽  
Annette Pettersson ◽  
Marja-Leena Rapinoja ◽  
Marja-Leena Kuitunen ◽  
...  
Keyword(s):  
Linear Correlation ◽  
Chemical Shifts ◽  
Piecewise Linear ◽  
Nerve Agent ◽  
Urine Samples ◽  
Ph Dependent ◽  
Nmr Identification

Phosphinsubstituierte Chelatliganden, XXIII [1] Darstellung und NMR-Spektren von Alkyl-arylphosphinothioformamiden, R(Ph)PC(S)NHMe / Phosphine-Substituted Chelate Ligands, XXIII [1] Synthesis and NMR Spectra of Alkyl-arylphosphinothioformamides, R(Ph)PC(S)NHMe

1987 ◽  
Vol 42 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Udo Kunze ◽  
Rolf Tittmann
Keyword(s):  
Chemical Shift ◽  
Linear Correlation ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Cone Angle ◽  
Coupling Constants ◽  
Methyl Isothiocyanate ◽  
Signal Sets ◽  
The Asymmetry ◽  
C Nmr

Abstract A series of alkyl-arylsubstituted N-methyl phosphinothioformamides, R(Ph)PC(S)NHMe (2 a-g), with varying bulkiness of the alkyl rest was synthesized from the racemic secondary phosphines 1a-g and methyl isothiocyanate. 1H and 13C NMR spectra of 2a−g reveal signal sets of diastereotopic nuclei due to the asymmetry of the molecule. The chemical shift and coupling constants were confirmed by simulation in case of 2b, c. The vicinal 31P−13C couplings of the menthyl and neomenthyl compounds 2f, g show an "anti-Karplus" behaviour (3J(gauche) > 3J(trans)) and allow the conformational assignment of the alicyclic group. The 31P chemical shifts of 2a−d give a linear correlation with the cone angle of the alkyl substituents quoted from literature.

14N- und 15N-NMR-Spektroskopie von Diazaphospholen und die lineare Korrelation der chemischen Verschiebung von zweifach koordiniertem N und P / 14N and 15N NMR Spectroscopy of Diazaphospholes and the Linear Correlation of the Chemical Shift of Two-Coordinate N and P

1986 ◽  
Vol 41 (5) ◽  
pp. 553-559 ◽  
Author(s):  
Alfred Schmidpeter ◽  
Bernd Wrackmeyer
Keyword(s):  
Linear Correlation ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
15N Nmr ◽  
Ground State Structure ◽  
Nitrogen And Phosphorus ◽  
System A ◽  
Nmr Study ◽  
15N Nmr Spectroscopy ◽  
Scalar Relaxation

A systematic natural abundance 15N NMR study of diazaphospholes is presented for the first time, giving accurate values for chemical shifts, δN , and coupling constants J(31P15N), J(15N1H ). 14N NMR spectra can be used to predict the magnitude of 1J( 31P14N) if the broadening of the 31P resonance by scalar relaxation is known. The relaxation behaviour of the 14N nuclei corresponds to that found in azoles indicating a comparable electronic ground state structure. The comparison of the chemical shifts, δN, in the diazaphospholes with δN of corresponding triazoles reveals differences which can be traced to the N-P σ-bonds and to the influence o f the phosphorus atom on the π-system. A linear correlation δN/δP exists coordinate nitrogen and phosphorus, respectively.

Correlation Analysis of Curing Agents

1984 ◽  
Vol 57 (4) ◽  
pp. 744-754 ◽  
Author(s):  
E. Morita
Keyword(s):  
Chemical Shift ◽  
Correlation Analysis ◽  
13C Nmr ◽  
Linear Correlation ◽  
Chemical Shifts ◽  
Amino Nitrogen ◽  
Phenyl Group ◽  
Negative Slope ◽  
Nmr Chemical Shift ◽  
Acceleration Rate

Abstract The linear correlation of the pKa to the σ* constants of the substituted phenylthio group indicates the validity of the σ* being equal to the sum of the Hammett's constant of these substituent groups and the σ* of the phenyl group (0.6). The inhibitory activity of the compound LSR depends on the reactivity of BtSSR with BtSH and the general stability of the mixed disulfides which form during the curing process. For BtSSR as accelerators, the Hammett's rule applies to scorch delay time versus σ* constant as the variable with negative slope in the LFER. In benzothiazole-2-sulfenamides, the 13C NMR chemical shift of the carbon at the 2-position of the benzothiazolyl group (C8) is consistently greater than the chemical shift at the carbon adjacent to the amino nitrogen (CN) in the same molecule. It indicates that the electronic distribution at the S-N bond is consistently more positive at the S atom and more negative at the amino nitrogen. The 13C NMR chemical shift at C8 is inversely proportional to the σ* constant of the amino substituents. A wider range of amino substituents is applicable for the correlation analysis with 13C chemical shifts than σ* constants as the variable. When benzothiazole-2-sulfenamides are used as accelerators, two linear relationships with slopes of opposite signs are obtained for the N-substituted phenyl and the N-alkyl sulfenamides, respectively, in the relationship of the scorch delay to the 13C8 chemical shift or the σ* constant. Longer scorch delay was obtained with the pertinent electron-withdrawing phenyl or the sterically hindered alkyl substituents. The more basic amino derivatives give a faster acceleration rate and a higher crosslink efficiency. A significant linear correlation was obtained for scorch delay versus Hammett's σ constant of the phenyl substituents of the N,N′-dithiobisformanilides as vulcanizing agents.

Linear correlation of the barriers to pyramidal inversion of phosphorus with the31P chemical shifts of acylphosphines

1981 ◽  
Vol 30 (8) ◽  
pp. 1438-1445
Author(s):  
I. I. Chervin ◽  
M. D. Isobaev ◽  
Yu. I. �l'natanov ◽  
Sh. M. Shikhaliev ◽  
L. V. Bystrov ◽  
...  
Keyword(s):  
Linear Correlation ◽  
Chemical Shifts ◽  
Pyramidal Inversion

13C N.M.R. STUDIES: PART V. CARBON-13 SPECTRA OF SOME SUBSTITUTED STYRENES

1965 ◽  
Vol 43 (2) ◽  
pp. 510-520 ◽  
Author(s):  
K. S. Dhami ◽  
J. B. Stothers
Keyword(s):  
Linear Correlation ◽  
Carbonyl Compounds ◽  
Chemical Shifts ◽  
Vinyl Carbon ◽  
Polar Substituents

The 15.1 Mc/s 13C n.m.r. spectra of 23 substituted styrenes have been examined and the shieldings of the various carbon nuclei determined. Several meta- and para-substituted derivatives were included to study the effects of polar substituents on the vinyl carbon chemical shifts. In agreement with previous proposals, a linear correlation with the Hammett σ parameter is found for the β-carbon shieldings, but not for those of the α-carbons. Nine ortho-substituted examples and two α-substituted compounds were investigated to compare their chemical shifts with results for related carbonyl compounds. While the 13C data exhibit marked differences in the hindered compounds, the variations differ from those observed in the more polar carbonyl systems.

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