Dissociation of substituted benzenesulphonamides in water, methanol and ethanol

Ludwig, Miroslav; Pytela, Oldřich; Kalfus, K.; Večeřa, M.

doi:10.1135/cccc19841182

Cited by 18 publications

(17 citation statements)

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“…From the infrared spectral data of the investigated compounds only the wavenumbers of the asymmetric SO 2 vibration, n as ðSO 2 Þ and the arithmetic mean of the symmetric and asymmetric NH 2 stretching vibrations, nðNH 2 Þ were found to correlate with the dissociation constants, the Hammett substituent constants, the PM3 S¼ ¼O bond orders and the oxygen atom charge densities; Eqs. (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). This is in accordance with a previous observation [13] that for several organic compounds containing SO 2 groups only the wavenumbers of the n as ðSO 2 Þ but not for the, n s ðSO 2 Þ vibration correlate satisfactorily with the s substituent constants.…”

Section: Resultsmentioning

confidence: 99%

“…However, there is no systematic investigation of substituent effects on these chemical shifts. The most systematic approach to the study of substituent effects on both IR and NMR spectral data of substituted benzenesulfonamides can be found in the paper of De Benedetti et al [1] Recently, dissociation constants of substituted benzenesulfonamides in various solvents have been measured and treated by the Hammett equation [10][11][12]. The dissociation constants determined in three selected solvents were taken as a measure of the acidity of the benzenesulfonamide system and used in our further investigation.…”

Section: Introductionmentioning

confidence: 99%

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Structure-Reactivity-Spectra Correlations for Substituted Benzenesulfonamides

Perjéssy

Kolehmainen²,

Fabian

et al. 2002

Sulfur Letters

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The infrared absorption bands of the S¼ ¼O and NÀ ÀH stretching vibrations as well as the natural abundance 13 C and the 17 O NMR chemical shifts were measured for fifteen substituted benzenesulfonamides in CDCl 3 and acetone-d 6 . For the unsubstituted compound the natural abundance 33 S NMR chemical shift was also measured in acetone-d 6 PM3 charge densities and bond orders were calculated for the completely optimised geometry. Mutual correlations are reported between the wave numbers of the asymmetric SO 2 stretching vibration, the arithmetic means of symmetric and asymmetric NH 2 stretching vibrations, Hammett s or s þ substituent constants, dissociation constants, 1 H, 13 C, 15 N and 17 O NMR chemical shifts as well as the PM3 S¼ ¼O and NÀ ÀH bond orders and hydrogen, nitrogen and oxygen atom charge densities. The results of the correlation analysis showed that the factors determining the electronic structure and controlling the dissociation equilibria, the IR and NMR spectral properties of substituted benzenesulfonamides must be the same.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structure-Reactivity-Spectra Correlations for Substituted Benzenesulfonamides

Perjéssy

Kolehmainen²,

Fabian

et al. 2002

Sulfur Letters

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“…The dissociation constants of all the substances at 25°C in methanol (MeOH), acetonitrile (AN), N,N-dimethylformamide (DMF), and pyridine (Py) were determined by potentiometric titrations using TITRALAB 3 automatic titrator (Radiometer). The method of measurement and the electrode arrangement used were the same as in our previous paper 10 . Each measurement was repeated three to five times.…”

Section: Methodsmentioning

confidence: 99%

Effect of para Substitution on Dissociation of N-Phenylbenzenesulfonamides

Mansfeld

Pařík

Ludwig

2004

Collect. Czech. Chem. Commun.

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The reaction of substituted anilines and benzenesulfonyl chlorides has been used to prepare 49 substituted N-phenylbenzenesulfonamides of general formula 4-X-C 6 H 4 SO 2 NHC 6 H 4 -Y-4′. Their purity was checked by elemental analysis. The substituents X and Y include H, CH 3 , CH 3 O, Cl, Br, CN, and NO 2 . The dissociation constants of all compounds were determined by potentiometric titration in methanol, acetonitrile, N,N-dimethylformamide, and pyridine. The obtained dissociation constants, pK HA , were correlated with various sets of substituent constants. It was found that the effects of substituents X and Y on the dissociation are best described by using the Hammett equation with σ p constants and the Yukawa-Tsuno equation with σ p -and σ p constants, respectively. This result confirms the direct conjugation of Y substituent with the reaction centre. The explained variability using the additive model was above 96% in all the solvents used. The data also provided information about the transmission effect of the SO 2 group. The average dissociation constants were further processed by the latent variables methods, principal components and conjugated deviations analyses.

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“…pK a values of sulfonamides were determined both by potentiometric titrations [21][22][23][24] and also by UV-spectroscopic analysis [30]. But for quinolines UV-spectroscopic determination were applied most often [49,50].…”

Section: Introductionmentioning

confidence: 99%

“…Determination of acidity constants could be performed with the experimental procedures based on potentiometric titration [20][21][22][23][24][25][26][27], spectroscopic determination (UV-VIS [20,25,26,[28][29][30][31][32], NMR [33,34] and even EPR [35]), chromatography (RP HPLC [36][37][38][39]) and capillary electrophoresis [25,[40][41][42][43][44][45][46][47][48]. pK a values of sulfonamides were determined both by potentiometric titrations [21][22][23][24] and also by UV-spectroscopic analysis [30].…”

Section: Introductionmentioning

confidence: 99%