No abstract

No abstract

ALEXEI N. PANKRATOV, INNA M. UCHAEVA, and ALEXANDER N. STEPANOV. Can. J. Chem. 71, 674 (1993) The oxidation of phenothiazine in dilute solutions of sulphuric acid leads to the corresponding cation radical. Using a potentiometric technique, a pK, value of 5.72 ? 0.05 was determined for phenothiazine. The kinetics has been studied and participation of both protonated and unprotonated oxidant in the oxidation reaction has been confirmed. Using a voltammetric technique with a rotating disk electrode, the anodic oxidation of phenothiazine was shown to be a oneelectron diffusion-controlled process. A quantum chemical explanation was found for the direction of phenothiazine protonation and the absence of a dimerization stage of oxidation.ALEXEI N. PANKRATOV, INNA M. UCHAEVA et ALEXANDER N. STEPANOV. Can. J . Chem. 71, 674 (1993) L'oxydation de la phknothiazine, en solutions dilukes d'acide sulfurique, conduit au cation radical. Faisant appel a une technique potentiomktrique, on a dttermink un pK, de 5,72 * 0,05 pour la phenothiazine. On a ktudi6 la cinttique de la reaction et on a dCmontr6 que l'oxydant proton6 aussi bien que le non proton6 participent a la r6action d'oxydation. Faisant appel a la technique de voltamp6romttrie avec une tlectrode a disque tournant, on a dCmontr6 que l'oxydation anodique est une rkaction impliquant un klectron dans un processus contr616 par la diffusion. On a expliquk la direction de la protonation de la phenothiazine et I'absence d'ktape de dimkrisation durant I'oxydation.[Traduit par la rkdaction]

By means of the PM3 method it has been shown that the protonation of 2-, 3 4-methoxyanilines, 4-methylthioaniline, 2-, 3-, 4-aminobenzoic acids, 2 3-, 4-nitroanilines in the gaseous phase proceeds via the amine nitrogen atom. The same result, attributed to the aqueous medium, was obtained for 4-methoxyaniline, 4-aminobenzoic acid and 4-nitroaniline.

By the PM3 method, standard values of entropy, heats and Gibbs energies of formation and dipole moments of the molecules have been computed for a series of inorganic and organic antimony compounds.Linear dependences P exper = bP theor (where P is any of the mentioned properties) have been stated, allowing a priori evaluation of thermodynamic characteristics and molecular dipole moments of Sb-containing substances. It has been concluded that triphenylstibinedichloride in benzene solution, as well as triphenylstibinehydroxychloride in dioxane medium, exist in the form of trigonal bipyramid with two axial chlorine and oxygen atoms.