INFLUENCE OF TEMPERATURE ON THE STABILITY OF 2-ETHYLIMIDAZOLE AU (III) COMPLEXES
Abstract and keywords
Abstract (English):
This article deals with the complexation of gold (III) with 2-ethylimidazole at a temperature range of 278-328 K by potentiometric titration. The reduction of the Au/[AuCl4]- system potential during the titration process at all temperatures under study indicates a reduction of the equilibrium concentration of [AuCl4]- and their coupling into complexes. The non-linearity of the dependence of E on lgCL is characteristic for the systems in which stepwise complexation occurs. We calculated the common stability constants of the complexes [Au(2-EI)Cl3] and [Au(2-EI)2Cl2]Cl (at 298 K lgβ1 = 6.14±0.06; lgβ2 = 13.18±0.08). The stability of the complexes grows with increasing of temperature. The temperature factor affects the stability of the bisubstituted complex to a greater extent (at a rise in temperature by 50 °C the stability of the bisubstituted complex increases by 2.69 log units, at the same temperature interval the stability of the monosubstituted complex increases by 1.32 log units).

Keywords:
potentiometry, step complexation, gold (III), 2-ethylimidazole, stability constant, temperature factor
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References

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