Chinese Journal of Chromatography

Chinese Journal of Chromatography

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Determination of kinetic transformation of two geometrical isomers of the ［Fe(PDT)3］2+ by high performance liquid chromatography

ZHU Weihuang1, WU Fengchang2, HUANG Tinglin1   

  1. 1.School of Environment and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China; 2.State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, the Chinese Academy of Sciences, Guiyang 550002, China
  • Received:2008-10-27 Revised:2008-10-27 Online:2008-10-27 Published:1983-09-25
  • Contact: WU Fengchang2

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Abstract: 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 xeln［(xe-x0)/(xe-x)］ and t(min) were as follows: xeln［(xe-x0)/(xe-x)］=0.082t+0.729 (r2=0.9911, T=45 ℃), xeln［(xe-x0)/(xe-x)］=0.049t+0.598 (r2=0.9987, T=40 ℃), xeln［(xe-x0)/(xe-x)］=0.022t+0.586 (r2=0.9987, T=35 ℃), xeln［(xe-x0)/(xe-x)］=0.012t+0.591(r2=0.9988, T=30 ℃). The activation enthalpy (ΔH), activation entropy (ΔS), and activation energy (ΔEa) characterizing the kinetic transformation were as follows: ΔH=103.84 kJ·mol-1, ΔS=271.93 J·mol-1·K-1, ΔEa=86.74 kJ·mol-1 (fac-isomer→mer-isomer); ΔH=106.47 kJ·mol-1, ΔS=257.65 J·mol-1·K-1, ΔEa=94.43 kJ·mol-1 (mer-isomer→fac-isomer).

Key words: ｛Fe［3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine］3｝2+, geometrical isomers, kinetic transformation , metal complex, high performance liquid chromatography (HPLC)