Kinetics and mechanism of substitution of iron(II)–triazine complexes by 1,10-phenanthroline

摘要: The kinetics and mechanism of substitution some iron(II)–triazine complexes, namely \( {\text{Fe}}({\text{PDT}})_{3}^{2 + } \), {\text{Fe}}({\text{PDTS}})_{3}^{4 - {\text{Fe}}({\text{PPDT}})_{3}^{2 \) {\text{Fe}}({\text{PPDTS}})_{3}^{7 (PDT = 3-((2-phenyl)-5,6-diphenyl))-1,2,4-triazine, PDTS 3-(2-pyridyl)-5,6-bis(4-phenylsulfonicacid)-1,2,4-triazine disodium salt, PPDT 3-((4-phenyl-2-pyridyl)-5,6-diphenyl)-1,2,4-triazine PPDTS 3-(4-(4-phenylsulfonicacid)-2-pyridyl)-5,6-bis(4-phenylsulfonicacid)-1,2,4-triazine trisodium salt) by 1,10-phenanthroline (phen) have been studied conventional spectrophotometry in acetate buffers over the pH range 3.6–5.6, following absorbance triazine (tz) complexes at their respective absorption maxima. reactions were carried out under pseudo-first-order conditions, that is, [phen] ≫ [Fe(II)–triazine]. found to be first order both Fe(II)triazine complex phen. rates increase with increasing pH. Plots kobs versus are linear positive intercepts, also plots against 1/[H+] intercepts on rate axes, indicating proceed phen– hydrogen ion–dependent independent paths. From kinetic data obtained 25–55 °C, specific constants thermodynamic parameters computed.