The inductive constants of the corresponding heterocyclic fragments were calculated on the basis of data on the pKa values obtained by potentiometric titration of derivatives of indole, carbazole, 3-methylcarbazole, tetrahydrocarbazole, 6-methyltetrahydrocarbazole, and phenothiazine. The σR oconstant of the 9-carbazolyl group was also calculated. The enthalpy and entropy of acidic dissociation were calculated from data on the effect of the temperature on the pKa of 9-carbazolylacetic acid. It is shown that the entropy contribution to the free energy of dissociation of 9-carbazolylacetic acid predominates.
ASJC Scopus subject areas
- Organic Chemistry