Collect. Czech. Chem. Commun. 1985, 50, 2065-2076

Relationships among structure, reactivity towards thiols and basicity of phenylhydrazonopropanedinitriles

Ernest Šturdík, Marián Antalík, Pavol Sulo, Štefan Baláž, Edita Ďurčová and Ľudovít Drobnica

Department of Technical Microbiology and Biochemistry, Slovak Institute of Technology, 812 37 Bratislava


Data required for characterization of reactivity of ortho-, meta-, and para-substituted derivatives by first and second order rate constants were obtained from spectrophotometric investigation of reaction kinetics of phenylhydrazonopropanedinitriles with model thiols. The reactivity has been found to be linearly dependent on Hammett constants of substituents. Similar dependence revealed the basicity characterized by pKa values determined spectrophotometrically. Whilst reactivity and basicity of meta- and para-substituted derivatives is dependent, ortho-substituted derivatives did not obey any simple relation between reactivity and basicity. This finding is important for utilization of ortho-derivatives of phenylhydrazonopropanedinitrile when studying the uncoupling effect of these substances upon oxidative and photosynthetic phosphorylation.