Hydrogen bond in o-phosphorus-substituted benzoic acids

Author(s):  
E. I. Matrosov ◽  
N. A. Bondarenko ◽  
E. N. Tsvetkov ◽  
M. I. Kabachnik
Author(s):  
Hiroyuki Ishida

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.


1960 ◽  
Vol 38 (5) ◽  
pp. 728-735 ◽  
Author(s):  
W. F. Forbes ◽  
A. R. Knight ◽  
D. L. Coffen

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.


1999 ◽  
Vol 64 (10) ◽  
pp. 1617-1628 ◽  
Author(s):  
Oldřich Pytela ◽  
Ondřej Prusek

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.


1994 ◽  
Vol 59 (9) ◽  
pp. 2029-2041
Author(s):  
Oldřich Pytela ◽  
Taťjana Nevěčná

The kinetics of decomposition of 1,3-bis(4-methylphenyl)triazene catalyzed with 13 substituted benzoic acids of various concentrations have been measured in 25 vol.% aqueous methanol at 25.0 °C. The rate constants observed (297 data) have be used as values of independent variable in a series of models of the catalyzed decomposition. For the catalytic particles were considered the undissociated acid, its conjugated base, and the proton in both the specific and general catalyses. Some models presumed formation of reactive or nonreactive complexes of the individual reactants. The substituent effect is described by the Hammett equation. The statistically best model in which the observed rate constant is a superposition of a term describing the dependence on proton concentration and a term describing the dependence on the product of concentrations of proton and conjugated base is valid with the presumption of complete proton transfer from the catalyst acid to substrate, which has been proved. The behaviour of 4-dimethylamino, 4-amino, and 3-amino derivatives is anomalous (lower catalytic activity as compared with benzoic acid). This supports the presumed participation of conjugated base in the title process.


2009 ◽  
Vol 74 (1) ◽  
pp. 29-42 ◽  
Author(s):  
Vilve Nummert ◽  
Mare Piirsalu ◽  
Signe Vahur ◽  
Oksana Travnikova ◽  
Ilmar A. Koppel

The second-order rate constants k (in dm3 mol–1 s–1) for alkaline hydrolysis of phenyl esters of meta-, para- and ortho-substituted benzoic acids, X-C6H4CO2C6H5, have been measured spectrophotometrically in aqueous 0.5 and 2.25 M Bu4NBr at 25 °C. The substituent effects for para and meta derivatives were described using the Hammett relationship. For the ortho derivatives the Charton equation was used. For ortho-substituted esters two steric scales were involved: the EsB and the Charton steric (υ) constants. When going from pure water to aqueous 0.5 and 2.25 M Bu4NBr, the meta and para polar effects, the ortho inductive and resonance effects in alkaline hydrolysis of phenyl esters of substituted benzoic acids, became stronger nearly to the same extent as found for alkaline hydrolysis of C6H5CO2C6H4-X. The steric term of ortho-substituted esters was almost independent of the media considered. The rate constants of alkaline hydrolysis of ortho-, meta- and para-substituted phenyl benzoates (X-C6H4CO2C6H5, C6H5CO2C6H4-X) and alkyl benzoates, C6H5CO2R, in water, 0.5 and 2.25 M Bu4NBr were correlated with the corresponding IR stretching frequencies of carbonyl group, (ΔνCO)X.


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