A Web Tool for Calculating Substituent Descriptors Compatible with Hammett Sigma Constants [PDF]
Chemistry–Methods, 2021 Electron donating or accepting power of organic substituents is an important parameter affecting many properties of parent molecules, most notably their reactivity and pKa of ionizable groups. These substituent properties are usually described by Hammett sigma constants obtained by measuring ionization of substituted benzoic acids ...
P. Ertl
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Determination of Hammett Sigma Constants by Intramolecular Hydrogen Bonding [PDF]
Nature, 1958 THE extensive literature that exists concerning Hammett's σ-constants has been subjected to several recent reviews, including a compilation and examination of available data1, a discussion of the significance and limitations of the concepts involved2, and an attempt to deduce best values and probable errors for the σ-values3.
A T Shulgin
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Donor Strengths Determination of Pnictogen and Chalcogen Ligands by the Huynh Electronic Parameter and Its Correlation to Sigma Hammett Constants [PDF]
Chemistry - A European Journal, 2019 Abstract The suitability and accuracy of the Huynh electronic parameter (HEP) was further tested to reveal remote substituent effects in pyridines, which are located five or six bonds away from the reporter probe.
Jia Nuo Leung +2 more
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Sigma Hole Potentials as Tools: Quantifying and Partitioning Substituent Effects. [PDF]
J Phys Chem A, 2023 Empirical substituent constants, such as the Hammett parameters, have found important utility in organic and other areas of chemistry. They are useful both in predicting the impact of substitutions on chemical processes and in rationalizing after-the ...
Donald KJ, Pham N, Ravichandran P.
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DFT study, and natural bond orbital (NBO) population analysis of 2-(2-Hydroxyphenyl)-1-azaazulene tautomers and their mercapto analouges [PDF]
Scientific ReportsTheoretical research on the keto-enol tautomerization of 2-(2-Hydroxyphenyl)-1-aza azulene (2HPhAZ) and its thiol-thione (2MPhAZ) analouge has been performed using the density functional B3LYP method with the 6–311 + + G(2d,2p) basis set in gas and ...
Shimaa Abdel Halim +3 more
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Resonance Effect in Hammett Relationship. II. Sigma Constants in Electrophilic Reactions and their Intercorrelation [PDF]
Bulletin of the Chemical Society of Japan, 1959 Yasuhide Yukawa, Yuho Tsuno
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Determination and structural correlation of pKBH+ for meta- and para- substituted benzamides in sulfuric acid solutions [PDF]
Journal of the Serbian Chemical Society, 2006 The protonation of some meta and para substituted benzamides in sulfuric acid solutions was studied by UV spectroscopy in the 190–350 nm region. Principal component analysis was applied to separate the effect of protonation from the medium effect.
EMIL POPOVSKI, GORAN STOJKOVIC
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The Substituent Effect on the Radical Scavenging Activity of Apigenin
Molecules, 2018 Flavonoids widely found in natural foods are excellent free radical scavengers. The relationship between the substituent and antioxidative activity of flavonoids has not yet been completely elucidated. In this work, the antioxidative activity of apigenin
Yan-Zhen Zheng +3 more
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Synthesis, IR and NMR spectral correlations in some symmetrical diimines
Bulletin of the Chemical Society of Ethiopia, 2014 A series of diimines have been synthesized by coupling of diamine with substituted benzaldehydes. The purities of these diimines were checked by their analytical and spectroscopic data. The spectral frequencies νCN (cm-1), NMR chemical shifts (δ, ppm) of
G. Thirunarayanan
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Chemosphere, 2003 The rate constants for hydroxyl radical reaction toward a set of nitroaromatic substrates kS, have been measured at 25 degrees C using competition experiments in the UV/H2O2 process. For a given pair of substrates S1 and S2, the relative reactivity beta (
F. G. García Einschlag +2 more
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