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Determination of Lipophilicity Constants of Sulfonamide Substituents
Journal of Chemical Education, 2001This article describes a simple laboratory activity using reversed-phase thin-layer chromatography (a stationary nonpolar phase and a mobile polar phase). The Rf values determined for sulfonamides by means of reversed-phase thin-layer chromatography are used to calculate the chromatographic parameter Rm and the lipophilicity constants (π) of different ...
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The Journal of Organic Chemistry, 2002
The established rates of glycoside hydrolysis reactions were analyzed using free energy relationship plots based on substituent constants that depend on whether the substituent is axial or equatorial. In all cases good correlations were found when assuming either that the transition state had a charged ring-oxygen atom or that it had a charged anomeric
Bols, M. +2 more
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The established rates of glycoside hydrolysis reactions were analyzed using free energy relationship plots based on substituent constants that depend on whether the substituent is axial or equatorial. In all cases good correlations were found when assuming either that the transition state had a charged ring-oxygen atom or that it had a charged anomeric
Bols, M. +2 more
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Substituent constants for predicting aromatic molecular quadrupole moments
Chemical Physics Letters, 2006Abstract Work in our group has shown a direct relationship between arene–cation binding enthalpies and the aromatic quadrupole moment ( Θ zz ); the more negative the Θ zz value, the greater the arene–cation binding enthalpy. The ability to predict aromatic Θ zz values from the aromatic substitution pattern would therefore allow for the ...
Dianne Tran +3 more
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Substituent effects on hyperfine coupling constants
198827 monosubstituted benzenes OX were measured either as pure liquids or in concentrated solutions. We use toluene as a model case to discuss the observed features and the assignment procedure. Three spectra are shown in Figure 5.1. At 3 kG three pairs of lines are observed (top).
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Induction and resonance constants of butadienyliron tricarbonyl substituents
Bulletin of the Academy of Sciences of the USSR Division of Chemical Science, 1976In dieneiron tricarbonyls the π-electron density in the 1 position of the coordinated butadiene system is higher than in the 2 position, while the σ-electron density is distributed uniformly.
N. S. Nametkin +3 more
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Proton affinity of phosphoryl compounds and ??-substituent constants
Bulletin of the Academy of Sciences of the USSR Division of Chemical Science, 1991Based on the familiar Hammett-type equation pKa=pKa 0- $$\rho \sum\limits_i {\sigma _i ^\Phi } $$ , CNDO/2 calculations, and known literature data, we have obtained a linear dependence of the proton affinity (PA) of phosphoryl compounds XYZPO on the sum of the ...
L. N. Alekseiko +4 more
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A Critical Compilation of Substituent Constants
1978The practical usefulness of a correlation equation as well as its significance in theory strongly depend on its range of validity, not only as it is defined but also as its use is restricted in practice by the number of parameters actually known. Hence the tables of parameters are of primary importance and reflect the actual state of a given field.
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Inductive substituent constants σji from olefinic geminal 1h, 1h nmr coupling constants
Tetrahedron, 1981Abstract Theoretical and experimental arguments are presented supporting the postulate that olefinic NMR coupling constants 2 J HH are insensitive to β-substituent influences on the olefinic π orbital. A new set of substituent constants, σ J I , is proposed to measure directly the inductive substituent effect transmitted by σ-bonds. The previously
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Spectroscopic substituent constants for ligands
Inorganic Chemistry, 1975Luigi G. Marzilli +3 more
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