Determination of kinetic transformation of two geometrical isomers of the [Fe (PDT) 3]2+ by high performance liquid chromatography
Zhu, W.; Wu, F.; Huang, T.
Se Pu 26(5): 550-553
2008
ISSN/ISBN: 1000-8713 PMID: 19160751 Document Number: 623992
The kinetic transformation of the two isomers of the [Fe(PDT)3]2+ (PDT: 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine) was studied by high performance liquid chromatography. The transformation between two isomers was proved to be treated kinetically as the first-order reaction. At different reaction temperatures, the linear regression equations between x(e)ln[(x(e) - x(0))/(x(e) - x)] and t(min) were as follows: x(e)ln[(x(e) - x(0))/(x(e) - x)] = 0.082t + 0.729 (r2 = 0.9911, T = 45 degrees C), x(e)ln[(x(e) - x(0))/(x(e) - x)] = 0.049t + 0.598 (r2 = 0.9987, T = 40 degrees C), x(e)ln[(x(e) - x(0))/(x(e) - x)] = 0.022t + 0.586 (r2 = 0.9987, T = 35 degrees C), x(e)ln[(x(e) - x(0))/(x(e) - x)] = 0.012t + 0.591 (r2 = 0.9988, T = 30 degrees C). The activation enthalpy (delta H), activation entropy (delta S), and activation energy (delta Ea) characterizing the kinetic transformation were as follows: delta H = 103.84 kJ x mol(-1), delta S = 271.93 J x mol(-1) x K(-1), delta Ea = 86.74 kJ x mol(-1) (fac-isomer --> mer-isomer); delta H = 106.47 kJ x mol(-1), delta S = 257.65 J x mol(-1) x K(-1), delta Ea = 94.43 kJ x mol(-1) (mer-isomer --> fac-isomer).