113223-42-0Relevant articles and documents
Reaction between Tl(III)Acetate and 1,3,5-Triarylformazan - A Linear Free Energy Correlation of Oxidative Cyclisation
Balakrishnan, R.,Srinivasan, Vangular S.
, p. 771 - 775 (2007/10/02)
Tl(III) acetate oxidations of 1,3,5-triarylformazans have been studied in 90percent HOAc-10percent H2O (v/v).The oxidative cyclisation exhibits total second order kinetics.For 1 mol of Tl(III)acetate, 1 mol of formazan is consumed, yielding 95percent of tetrazolium salt.The reaction mixture does not initiate acrylonitrile polymerisation.The rate of oxidation is susceptible to polar influence of substituents in the phenyl rings of formazan.From the Hammett correlation (?o, ?p+, ?m), the reaction constants evaluated are -0.81, -0.75 and -0.80 respectively and the negative ρ-values are indicative of an electron deficient transition state.The high negative entropies of activation reveal that the transition state is more ordered, probably cyclic.The thermodynamic parameters have been subjected to Exner treatment and the plot of log kT2 versus log kT1 (T1 2) is linear, yielding the slope (=0.89) of less than unity and the isokinetic temperature calculated therefrom comes out to be 728 K, showing that the detailed structure-activity correlation is probably valid.From the influence of dielectric constant of the medium, it has been concluded that the reactants are dipolar in nature.
