Results 121 to 130 of about 3,044 (143)

Exploring the Electronic Influence on Coordination Complexes formed from appended Pyrrolidine Azothioformamide Ligands and Copper(I) salts. [PDF]

J Mol Struct
Tiwari L, Heiden ZM, Waynant KV.
europepmc   +1 more source

Estimation of Hammett sigma constants from calculated atomic charges using partial least squares regression

Journal of Chemometrics, 1996
Hammett constants describe the electronic donating or withdrawing capabilities of a given substituent. Since Hammett constants represent information of an electronic nature, their values are to be linked with atomic charges and orbital-derived parameters of the atoms of the substrate bearing the substituent.
Pierre Genix, Hervé Jullien, Rémi Le Goas   +2 more
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Molecular Quantum Similarity Measures from Fermi Hole Densities:  Modeling Hammett Sigma Constants

Journal of Chemical Information and Modeling, 2006
A new approach, based on the use of fragment Quantum Self-Similarity Measures (MQS-SM) as descriptors of electronic substituent effect in aromatic series, was proposed. The novelty of this approach consists of the fact that the corresponding MQS-SM are not derived, as usual, from ordinary density functions (DF) but from the so-called domain averaged ...
Xavier, Gironés, Robert, Ponec
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Simple Quantum Chemical Parameters as an Alternative to the Hammett Sigma Constants in QSAR Studies

Quantitative Structure-Activity Relationships, 1997
AbstractThe Hansch‐Fujita correlation analysis proved to be one of the major breakthroughs in the process of understanding relation between molecular properties and biological activity. In this approach the Hammett σ constants are used to characterize electronic effects of substituents. Experimentally determined σ constants have, despite their numerous
Peter Ertl
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Nitrogen-15 magnetic resonance spectroscopy. Correlation of the 15N-H coupling constants in aniline derivatives with Hammett .sigma. constants

Journal of the American Chemical Society, 1969
T, Axenrod, P S, Pregosin, M J, Wieder, G W, Milne   +3 more
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Hammett's Sigma Constants in Certain Electrophilic Reactions

The Journal of Organic Chemistry, 1952
D. E. Pearson, J. F. Baxter, J. C. Martin   +2 more
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Intramolecular Hydrogen Bonding. II. The Determination of Hammett Sigma Constants by Intramolecular Hydrogen Bonding in Schiff's Bases

Journal of the American Chemical Society, 1959
A. W. Baker, A. T. Shulgin
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Notes- Hammett Sigma Constants for m-and p-Benzoyl Groups

The Journal of Organic Chemistry, 1961
William White, Robert Schlitt, Donald Gwynn   +2 more
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Nuclear magnetic resonance studies of the bonding in aromatic systems. Correlation of Hammett sigma constants with methyl13C-H coupling constants and chemical shifts

Journal of the American Chemical Society, 1969
Claude H. Yoder, Richard H. Tuck, Ronald E. Hess   +2 more
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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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