Stability Constants and Rate Constants of Intramolecular Redox Decomposition of Cerium(IV) Complexes with Certain Hydroxycarboxylic Acids in Nitrate Medium

Resumo

Composition, stability constants and rate constants of intramolecular redox decomposition of cerium(IV) complexes with anions of quinic \({{\left( {{\text{CHOH}}} \right)}_{3}}{{\left( {{\text{C}}{{{\text{H}}}_{2}}} \right)}_{2}}{\text{C}}\left( {{\text{OH}}} \right)\)COOH, lactic \({\text{C}}{{{\text{H}}}_{3}}{\text{CH}}\left( {{\text{OH}}} \right){\text{COOH,}}\) tartaric \({\text{HOOCCH}}\left( {{\text{OH}}} \right){\text{CH}}\left( {{\text{OH}}} \right){\text{COOH}}\), and citric \({\text{HOOCC}}{{{\text{H}}}_{2}}{\text{C}}\left( {{\text{OH}}} \right)\left( {{\text{COOH}}} \right){\text{C}}{{{\text{H}}}_{2}}{\text{COOH}}\) hydroxycarboxylic acids have been determined by spectrophotometry, photometry, pH and kinetic measurements in nitrate medium in pH range 0–3 at ionic strength \(I = 2\) and \(295.15\) K. A direct linear correlation between stability constant logarithms and negative logarithms of rate constants of intramolecular redox decomposition of the studied complexes, which is absent in sulfate medium, has been revealed. The noted correlation can be considered as appearance of free energy linear relationship principle in coordination chemistry.