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Reparametrization and/or Determination of Hammett, Inductive, Mesomeric and AISE substituent constants for five Substituents: N+(CH3)3. CH2N+(CH3)3, CH2Py+, CH2SO2CH3 and PO(OCH3)2.
Authors: Pícha Jan | Cibulka Radek | Liška František | Pařík Patrik | Pytela Oldřich
Year: 2004
Type of publication: článek v odborném periodiku
Name of source: Collection of Czechoslovak Chemical Communications
Publisher name: Ústav organické chemie a biochemie AV ČR
Place: Praha
Page from-to: 2239-2252
Titles:
Language Name Abstract Keywords
cze Reparametrizace a určení Hammettových, induktivních, mesomerních a AISE substitučních konstant pro pět substituentů N+(CH3)3. CH2N+(CH3)3, CH2Py+, CH2SO2CH3 and PO(OCH3)2. Nevyplněno Dissociation constants, Benzoic acids, Substituent effects, Hammett equation, AISE, Quarternaly ammonium salts, Sulfones, Phosphonates
eng Reparametrization and/or Determination of Hammett, Inductive, Mesomeric and AISE substituent constants for five Substituents: N+(CH3)3. CH2N+(CH3)3, CH2Py+, CH2SO2CH3 and PO(OCH3)2. Ten meta and para substituted benzoic acid with substituents N+(CH3)3, CH2N+(CH3)3, CH2Py+, CH2SO2CH3 a PO(OCH3)2 were synthesized. Dissociation constants of these acids were determined in five solvents (water, ethanol, methanol, N,N-dimethylformamide, dimethylsulfoxide). Dissociation constants of benzoic acid derivatives with other substituents H, CH3, NHCOCH3, OCH3, F, Cl, Br, I, COCH3, CN, NO2, SO2CH3 were taken from the literature (calibration set). Substituent constants sigma_m, sigma_p, sigma_I, sigma_R a sigma_i for substituents N+(CH3)3, CH2N+(CH3)3, CH2Py+, CH2SO2CH3 a PO(OCH3)2 were calculated by nonlinear and PLS (partial least square, method with latent variables) calibration in three correlation models using calibration set. Nonlinear regression appears more suitable and more universal in comparison with PLS calibration. The advantage of nonlinear regression is independence on missing data in the solvent, evaluation of precision (standard deviation), the accessibility of necessary software, and easy calculation. However, on the contrary of PLS calibration, this procedure fails in calculation of substituent constants with description of properties of substituents (substituent constants sigma_I, sigma_R). The obtained values of substituent constants are in good agreement with those published in the literature. Dissociation constants, Benzoic acids, Substituent effects, Hammett equation, AISE, Quarternaly ammonium salts, Sulfones, Phosphonates

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