Hydrogen-bond relations between homoconjugates and heteroconjugates of substituted benzoic acids and benzoates in acetonitrile. Dissociation constants of substituted benzoic acids

1970 ◽  
Vol 92 (24) ◽  
pp. 7025-7030 ◽  
Author(s):  
Izaak M. Kolthoff ◽  
Miran K. Chantooni
Keyword(s):  
Hydrogen Bond ◽  
Dissociation Constants ◽  
Benzoic Acids ◽  
Substituted Benzoic Acids

Chemometric Analysis of Substituent Effects. XII. Application of Relationship Between 2- and 4-Substitution of Benzene Ring to Study ortho Effect in Selected Compounds with Different Reaction Centres

1999 ◽  
Vol 64 (10) ◽  
pp. 1617-1628 ◽  
Author(s):  
Oldřich Pytela ◽  
Ondřej Prusek
Keyword(s):  
Hydrogen Bond ◽  
Benzoic Acid ◽  
Electron Pair ◽  
Dissociation Constants ◽  
Substituent Effects ◽  
Reaction Centre ◽  
Benzoic Acids ◽  
Hydrogen Bond Formation ◽  
Latent Structures ◽  
Substituted Benzoic Acids

Three model compounds have been selected to study the relationship between ortho and para substitution: benzoic acid, phenol, and aniline. Sixteen substituents have been chosen involving also those capable of potential interaction between ortho substituent and the reaction centre. For the combinations given, literature presents 25 pairs of data obtained by measuring a particular process for both the ortho and para substituted derivatives. The missing dissociation constants of 16 ortho substituted benzoic acids in water and ethanol and 16 para substituted benzoic acids in dimethyl sulfoxide and pyridine have been measured by potentiometric titration. The data matrices were submitted to analysis by the methods of projection of latent structures (PLS) and principal component analysis (PCA). It has been found that the substituent effects from ortho and para positions have the same character unless the ortho substituents interact with the reaction centre. Such interactions can change the experimentally found value by as much as 20% of its magnitude. The most significant interaction is a hydrogen bond formation. Out of the three models studied the most extensive interactions are present in benzoic acid, whereas almost none were observed in aniline. The capability of donation of electron pair to a hydrogen bond decreases in the substituent series COCH3 > SO2CH3 > NO2. The capability of donation of proton to a hydrogen bond with electron-pair donor decreases in the substituent series OH > NHCOCH3 ≈ SH > NH2 > SO2NH2.

scholarly journals Role of pK a in establishing the crystal structures of six hydrogen-bonded compounds of 4-methylquinoline with different isomers of chloro- and nitro-substituted benzoic acids

2021 ◽  
Vol 77 (11) ◽  
Author(s):  
Hiroyuki Ishida
Keyword(s):  
Hydrogen Bond ◽  
Shape Index ◽  
Benzoic Acids ◽  
Quinoline Ring ◽  
Nitrobenzoic Acid ◽  
Layer Structures ◽  
Acid And Base ◽  
Short Hydrogen Bond ◽  
Substituted Benzoic Acids ◽  
Hydrogen Bonded

The structures of the six hydrogen-bonded 1:1 compounds of 4-methylquinoline (C10H9N) with chloro- and nitro-substituted benzoic acids (C7H4ClNO4), namely, 4-methylquinolinium 2-chloro-4-nitrobenzoate, C10H10N+·C7H3ClNO4 −, (I), 4-methylquinoline–2-chloro-5-nitrobenzoic acid (1/1), C10H9N·C7H4ClNO4, (II), 4-methylquinolinium 2-chloro-6-nitrobenzoate, C10H9.63N0.63+·C7H3.37ClNO4 0.63−, (III), 4-methylquinolinium 3-chloro-2-nitrobenzoate, C10H9.54N0.54+·C7H3.46ClNO4 0.54−, (IV), 4-methylquinolinium 4-chloro-2-nitrobenzoate, C10H10N+·C7H3ClNO4 −, (V), and 4-methylquinolinium 5-chloro-2-nitrobenzoate, C10H10N+·C7H3ClNO4 −, have been determined at 185–190 K. In each compound, the acid and base molecules are linked by a short hydrogen bond between a carboxy (or carboxylate) O atom and an N atom of the base. The O...N distances are 2.5652 (14), 2.556 (3), 2.5485 (13), 2.5364 (13), 2.5568 (13) and 2.5252 (11) Å, respectively, for compounds (I)–(VI). In the hydrogen-bonded acid–base units of (III) and (IV), the H atoms are each disordered over two positions with O site:N site occupancies of 0.37 (3):0.63 (3) and 0.46 (3):0.54 (4), respectively, for (III) and (IV). The H atoms in the hydrogen-bonded units of (I), (V) and (VI) are located at the N-atom site, while the H atom in (II) is located at the O-atom site. In all the crystals of (I)–(VI), π–π stacking interactions between the quinoline ring systems and C—H...O hydrogen bonds are observed. Similar layer structures are constructed in (IV)–(VI) through these interactions together with π–π interactions between the benzene rings of the adjacent acid molecules. A short Cl...Cl contact and an N—O...π interaction are present in (I), while a C—H...Cl hydrogen bond and a π–π interaction between the benzene ring of the acid molecule and the quinoline ring system in (II), and a C—H...π interaction in (III) are observed. Hirshfeld surfaces for the title compounds mapped over d norm and shape index were generated to visualize the weak intermolecular interactions.

The Hammett substituent constants and effects of medium

1986 ◽  
Vol 51 (10) ◽  
pp. 2143-2150 ◽  
Author(s):  
Oldřich Pytela ◽  
Miroslav Ludwig ◽  
Miroslav Večeřa
Keyword(s):  
Factor Analysis ◽  
Principal Components Analysis ◽  
Excellent Agreement ◽  
Principal Components ◽  
Solvent Effects ◽  
Dissociation Constants ◽  
Benzoic Acids ◽  
Substituent Constants ◽  
Components Analysis ◽  
Substituted Benzoic Acids

The dissociation constants measured earlier for 35 substituted benzoic acids in seven solvents (water, methanol, ethanol, dimethylformamide, acetonitrile, sulfolane, and acetone) have been submitted to the principal components analysis and the factor analysis to produce sets of the Hammett substituent constants. The solvent effects have been evaluated on the dissociation constants of the substituted benzoic acids and, hence, also on the respective substituent constants. He differences have been compared between the substituent constants determined by the principal components analysis and by the factor analysis, the latter being found to be more suitable. The obtained sets of substituent constants have been confronted with literature data, and an excellent agreement has been found between the σ constants derived from the measurements in water with the sets of primary substituent constants and some other sets.

Dissociation constants of substituted benzoic acids in water and in organic solvents

1986 ◽  
Vol 51 (10) ◽  
pp. 2135-2142 ◽  
Author(s):  
Miroslav Ludwig ◽  
Václav Baron ◽  
Karel Kalfus ◽  
Oldřich Pytela ◽  
Miroslav Večeřa
Keyword(s):  
Potentiometric Titration ◽  
Organic Solvents ◽  
Solvent Effects ◽  
Dissociation Constants ◽  
Point Of View ◽  
Benzoic Acids ◽  
Hammett Equation ◽  
Substituent Constant ◽  
Reaction Constant ◽  
Substituted Benzoic Acids

Potentiometric titration has been used to measure dissociation constants of 38 monosubstituted benzoic acids in water and in 6 organic solvents (methanol, ethanol, dimethylformamide, acetonitrile, sulfolane, acetone). The results have been analyzed and interpreted from the point of view of substituent and solvent effects on the dissociation of the title substrates. It has been proved that solvents affect not only the reaction constant but also the substituent constant of the Hammett equation.

Solvent Effect on the Hammett Reaction Constant of Substituted Benzoic Acids

1993 ◽  
Vol 46 (1) ◽  
pp. 31 ◽  
Author(s):  
H Bartnicka ◽  
I Bojanowska ◽  
MK Kalinowski
Keyword(s):  
Solvent Effect ◽  
Dimethyl Sulfoxide ◽  
Dissociation Constants ◽  
Benzoic Acids ◽  
Hammett Equation ◽  
P Values ◽  
Reaction Constant ◽  
Substituted Benzoic Acids ◽  
Reaction Constants ◽  
Solvent Acidity

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. The reaction constants of the Hammett equation were found to depend on the solvent acidity and basicity expressed by the α and β parameters of Kamlet and Taft. The p values determined earlier in water and ethanol also obey this rule.

Electrostatic effects on ionization equilibria: Solvent dependence

1984 ◽  
Vol 49 (1) ◽  
pp. 179-189 ◽  
Author(s):  
Karel Kalfus ◽  
Zdeněk Friedl ◽  
Otto Exner
Keyword(s):  
Gas Phase ◽  
Carboxylic Acids ◽  
Dissociation Constants ◽  
Aprotic Solvents ◽  
Benzoic Acids ◽  
Cavity Model ◽  
Electrostatic Effects ◽  
Solvent Dependence ◽  
Ionization Equilibria ◽  
Substituted Benzoic Acids

Apparent dissociation constants of 3-substituted bicyclo[2,2,2]-octane-1-carboxylic acids I-III and of several substituted benzoic acids were measured in four pure solvents. The results - together with numerous literature data concerning dissociation in other solvents and in the gas phase - were compared with the prediction of the electrostatic theory. The theory fails to reproduce the essential features of the solvent dependence as it predicts generally too small effects and does not differentiate between protic and aprotic solvents. The mentioned goal cannot be achieved by any more sophisticated cavity model or by any other theory as far as it characterizes the solvent only through its bulk permittivity.

Chemometric Analysis of Substituent Effects. VI. A Study of ortho Effect in Dissociation of 2,6-Disubstituted Benzoic Acids

1995 ◽  
Vol 60 (5) ◽  
pp. 829-840 ◽  
Author(s):  
Jiří Kulhánek ◽  
Oldřich Pytela
Keyword(s):  
Latent Variables ◽  
Dissociation Constants ◽  
Additive Model ◽  
Substituent Effects ◽  
Point Of View ◽  
Steric Effects ◽  
Benzoic Acids ◽  
Hammett Equation ◽  
Substituent Constants ◽  
Substituted Benzoic Acids

Ten 2,6-disubstituted benzoic acids have been synthesized containing all possible combinations of the following substituents: CH3, OCH3, Cl, and NO2. The dissociation constants of these acids have been measured by potentiometric titration in methanol, acetone, dimethyl sulfoxide, dimethylformamide, acetonitrile, pyridine, and 1,2-dichloroethane. The experimental data obtained together with the pK values of 2-substituted benzoic acids in the same solvents have been analyzed from the point of view of ortho effect and additivity of disubstitution. The mutual interaction between substituents was found to represent only 0.12% of the variability due to substitution and to contribute to the overall variability of data less than the interaction between the substituent and solvent by a factor of about 13. The analysis of data by the method of multiple linear regression revealed a contribution of steric effects beside the effects transmitted through the aromatic skeleton. The 2- and 6-substituents effects are additive within the validity of the Hammett equation, and an addition of a multiplicative term describing interactions between the substituents is statistically insignificant. Nonlinear regression has been adopted in the additive model with multiplicative term to find the inner substituent constants including all the effects of substituents from ortho position: the term describing the interaction between 2- and 6-substituents is statistically insignificant in this model. An application of the method of conjugated deviations revealed two statistically significant latent variables. The first one explains 91.5% of the variability of data and is connected with the substituent effects transmitted through the aromatic skeleton. The second one explains 7.5% of variability of data and predominantly reflects the steric effects of substituents.

THE STUDY OF HYDROGEN BONDING AND RELATED PHENOMENA BY ULTRAVIOLET LIGHT ABSORPTION: PART III. THE STRENGTH OF THE DIMERIC HYDROGEN BOND IN SUBSTITUTED BENZOIC ACIDS AS A MEASURE OF ELECTRONIC AND STERIC INTERACTIONS

1960 ◽  
Vol 38 (5) ◽  
pp. 728-735 ◽  
Author(s):  
W. F. Forbes ◽  
A. R. Knight ◽  
D. L. Coffen
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Concentration Dependence ◽  
Intramolecular Hydrogen Bond ◽  
Light Absorption ◽  
Benzoic Acids ◽  
Steric Interactions ◽  
Substituted Benzoic Acids ◽  
Intramolecular Hydrogen ◽  
Methoxybenzoic Acid

The strength of the intermolecular (dimeric) hydrogen bond in substituted benzoic acids, as estimated from the observed concentration dependence of the ultraviolet absorption spectra, is found to vary with the nature and the position of the substituent. The effects of a number of substituents on the strength of the dimeric hydrogen bond can be rationalized in terms of the usual electronic and steric interactions. The data indicate that o-methoxybenzoic acid forms a stronger intramolecular hydrogen bond than o-fluorobenzoic acid.

Hydrogen bond in o-phosphorus-substituted benzoic acids

1981 ◽  
Vol 30 (7) ◽  
pp. 1318-1321 ◽  
Author(s):  
E. I. Matrosov ◽  
N. A. Bondarenko ◽  
E. N. Tsvetkov ◽  
M. I. Kabachnik
Keyword(s):  
Hydrogen Bond ◽  
Benzoic Acids ◽  
Substituted Benzoic Acids
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