Results 121 to 130 of about 576,075 (159)
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Hammett's Sigma Constants in Certain Electrophilic Reactions
Journal of Organic Chemistry, 1952J C Martin
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A Theoretical Treatment of Hammett's Sigma Constants
Recueil Des Travaux Chimiques Des Pays-Bas, 1953AbstractA theoretical treatment is given of the connection between the structure and the position of a substituent S and the value of σs, from the Hammett equation: log ks/ko = ρ · σs. The theory is based on a wave mechanical calculation of the effect of S on the localisation energy of a reaction. The equations derived make it possible to calculate σs,
F L J Sixma
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Linear 13C-H Coupling Constant-Hammett Sigma-Constant Relations in Substituted Benzaldehydes
Journal of Chemical & Engineering Data, 1972benzaldehydes, 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 +2 more
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1953
Abstract : The relative acidities of 8 m- and p-substituted thiophenols were obtained to determine the conjugative ability of the MeSO2 was significantly larger than that from BzOH, but smaller than that from phenols or anilines. This indicated the possibility of varying degrees of resonance interactions (involving an expansion of the s valence shell ...
HARRY M. ANDERSEN, F.G. BORDWELL
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Abstract : The relative acidities of 8 m- and p-substituted thiophenols were obtained to determine the conjugative ability of the MeSO2 was significantly larger than that from BzOH, but smaller than that from phenols or anilines. This indicated the possibility of varying degrees of resonance interactions (involving an expansion of the s valence shell ...
HARRY M. ANDERSEN, F.G. BORDWELL
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Journal of Physical Organic Chemistry, 2004 AbstractFor monosubstituted benzenes (Ph‐Z), Linderberg et al. demonstrated the validity of the equation ΔCEBE ≈ κσ, where ΔCEBE is the difference between the core‐electron binding energies (CEBE) of a specific carbon in monosubstituted benzene derivatives (Ph‐Z) and that of unsubstituted benzene (Ph‐H), κ is related to the reaction constant and σ is ...
Takahata Y.
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, 2001 Density Functional Theory (DFT) calculations show that there is a linear correlation between NICS values (aromaticity criterion) and experimental Hammett (Brown) constants (σp+), together with other computed parameters for p-substituted benzyl cations. ©
Iňaki Morao, I. H. Hillier
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Quantum chemical topology (QCT) descriptors as substitutes for appropriate Hammett constants.
Organic and biomolecular chemistry, 2005 A technique called quantum topological molecular similarity (QTMS) was recently proposed [J. Chem. Inf. Comput. Sc., 2001, 41, 764] in order to construct a variety of medicinal, ecological and physical organic QSAR/QSPRs, based on modern ab initiowave ...
P. J. Smith, P. Popelier
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Environmental Science and Technology, 2022
In this study, a representative redox mediator, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), and its para-substituted derivatives (TEMPOs: 4-hydroxyl-TEMPO, 4-acetylamino-TEMPO, and 4-amino-TEMPO) significantly accelerated the abatement of trace organic
Honglong Zhang +5 more
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In this study, a representative redox mediator, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), and its para-substituted derivatives (TEMPOs: 4-hydroxyl-TEMPO, 4-acetylamino-TEMPO, and 4-amino-TEMPO) significantly accelerated the abatement of trace organic
Honglong Zhang +5 more
semanticscholar +1 more source