Results 151 to 160 of about 300,019 (196)

Hammett constants of some (Trialkylsilyl)alkyl groups

Bulletin of the Academy of Sciences of the USSR Division of Chemical Science, 1961
1. The results confirm that in various phenylsilanes silicon can occur in the Si−(V) state on account of free 3d orbitals. 2. The specific effect of a silicon atom on β-functional groups is clearly determined by the specific character of the structure of these compounds together with the induction effects of the silyl and functional ...
E. A. Chernyshev, N. G. Tolstikova
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Constant no more: reevaluating Hammett constants through spin-crossover

Inorganic Chemistry Frontiers
The spin-crossover phenomenon helped re-evaluate the existing Hammett constants that incorrectly classify electron-withdrawing and electron-donating groups to explain and predict magnetic behaviours, chemical reactivity and beyond.
Igor Nikovskiy, Dmitry Aleshin, Aleksei Anisimov, Valentin Novikov, Yulia Nelyubina   +4 more
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Hammett constants of the pyrroline-2, 5-dione ring

Chemistry of Heterocyclic Compounds, 1976
The electronic effect of the pyrroline-2,5-dione ring on the benzene ring in the case of N-aryl compounds is close to the effect exerted by halogens. The overall electron-acceptor effect depends markedly on the nature of the solvent. The electron-donor effect of conjugation is small.
V. D. Romanenko, N. N. Kalibabchuk, A. A. Rositskii, V. G. Zalesskaya, V. E. Didkovskii, S. V. Iksanova   +5 more
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Hammett analysis of absolute carbene addition rate constants

Tetrahedron Letters, 1983
Abstract Absolute rate constants were determined for the additions of 5 5 -X-substituted ArCCl (X=CF 3 , Cl, H, CH 3 , CH 3 O) to tetramethylethylene, trimethylethylene, trans-pentene, and 1-hexene; good Hammett correlations were obtained with ϱ = +1.4 – 1.6.
R.A. Moss, L.A. Perez, N.J. Turro, I.R. Gould, N.P. Hacker   +4 more
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An Estimate of the Hammett Reaction Constant for the Basicities of Substituted Benzophenones

Nature, 1966
HAMMETT reaction constants ρ for the basicities of several series of carbonyl compounds are known and have been found to correlate linearly with the infra-red frequencies of the carbonyl bond1. This constant is not available for monosubstituted benzophenones (that is, substituted in one ring only), because the basicities of only a few of them have been
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Linear 13C-H coupling constant-Hammett sigma-constant relations in substituted benzaldehydes

Journal of Chemical & Engineering Data, 1972
benzaldehydes, measuring the CI3 -H coupling constant of the aldehydic proton. As expected, the greater ability of the trigonal carbon atom to transmit the electronic effects of substituent X to this proton is reflected in the much greater sensitivity of the Cl3-H coupling constant to the electronic nature of X. Again excellent linear J-a relationships
Claude H. Yoder, Charles D. Schaeffer, Ronald E. Hess   +2 more
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Correlation of stability constants of metal complexes with hammett's σ-factor

Journal of Inorganic and Nuclear Chemistry, 1966
Abstract A parameter is derived on thermodynamical grounds, which measures the variations in the stability of the metal complexes formed with a series of aromatic ligands, when the basicity of these ligands is altered by changes in substituents. This parameter is shown to be a linear function of Hammett's σ-factor for the substituents, using several
J.J.R.Fraústo da Silva, J.Gonçalves Calado   +1 more
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Do Hammett constants model electronic properties in QSARs?

Science of The Total Environment, 1991
Abstract A set of 22 alkylated or halogenated phenols was subjected to a comparative analysis of the solution acidity as expressed by p K a , the respective σ Hammett substituent constants and the gas-phase acidity. Quantum chemical calculations within the PM3 model lead to the anion ionization potential as an intrinsic acidity scale for the phenols,
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Solvent Effect on the Hammett Reaction Constant of Substituted Benzoic Acids

Australian Journal of Chemistry, 1993
Potentiometric titration has been used to measure dissociation constants of 13 monosubstituted benzoic acids in nitromethane, benzonitrile , acetonitrile , propylene carbonate, acetone, N,N-dimethylformamide, dimethyl sulfoxide, methanol and formamide.
H Bartnicka, I Bojanowska, MK Kalinowski
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⁷⁷Se NMR spectroscopy as a sensitive probe for Hammett σ constants.

The Journal of organic chemistry, 2015
Herein we showcase the use of a combination of (1)H, (13)C, and (77)Se NMR spectroscopy as a sensitive tool for correlation analysis. A series of substituted O-aryl selenocarbamates [ArOC(Se)N(CH3)2] and Se-aryl selenocarbamates [ArSeC(O)N(CH3)2] have been investigated by means of (1)H, (13)C, and (77)Se NMR spectroscopy.
Anne, Sørensen, Brian, Rasmussen, Michael, Pittelkow   +2 more
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