Results 131 to 140 of about 1,896 (172)

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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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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Solvent effect on the hammett reaction constant for the electroreduction of substituted benzophenones

Journal of Physical Organic Chemistry, 1992
AbstractSolvent effects on the Hammett ρ value for the cathodic reduction of substituted benzophenones were determined. The electrochemistry of a series of 11 compounds was studied in acetonitrile, acetone, dimethyl sulphoxide, propylene carbonate, N,N‐dimethylformamide, N,N‐dimethylacetamide, N,N‐diethylformamide and hexamethylphosphoric triamide. The
Jan S. Jaworski, Marcin Malik, Marek K. Kalinowski   +2 more
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Hammett-Taft constants of substituted 2- and 4-quinazolinyl groups

Bulletin of the Academy of Sciences of the USSR Division of Chemical Science, 1991
From the chemical shifts of the meta- and para-carbon atoms of the phenyl group in phenylquinazolines the σI and σR0 constants of 2- and 4-quinazolinyl groups were determined. Correlation equations which enable us to calculate the σ constants of various substituted 2- and 4-quinazolinyl groups are proposed.
S. G. Baram, O. P. Shkurko, V. P. Mamaev
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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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Towards the unification of the substituent (position) constants in Hammett-Streitwieser equation

Tetrahedron, 1972
Abstract An extension of position constants in the Hammett-Streitwieser equation (HSE) is given. An analogy of interactions between electron repelling group Y and attacking electrophylic agent as well as between electron attracting group and attacking nucleophylic agent is postulated to explain wide applicability of the HSE both the unsubstituted and
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Temperature Dependence of Hammett Reaction Constants

The Journal of Chemical Physics, 1957
A. Fischer, J. Vaughan
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Hammett substituent constants in 2-phenylbenzotriazole

Collection of Czechoslovak Chemical Communications, 1969
I. Čepčiansky, J. Majer
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A Web Tool for Calculating Substituent Descriptors Compatible with Hammett Sigma Constants**

Chemistry Methods, 2022
Peter Ertl
exaly