COMPLEXATION OF IRON(III) WITH TSC AND FTSC IN H2SO4 SOLUTIONS OF VARIABLE COMPOSITION

Abstract

The process of complex formation of iron (III) with thiosemicarbazide and 1-formyl-3-thiosemicarbazide in H2SO4 solutions of various concentrations was studied using the potentiometric method. The stability constants of the resulting complexes were calculated, and the ionization constants of the ligands were estimated under the same conditions. It was shown that the stepwise nature of complex formation does not depend on the concentration of hydrogen ions. However, the stability of the complexes decreases with increasing pH. A study of the complex formation of iron(III) with thiosemicarbazide and its acyl derivative showed that there are both similarities and differences in the nature of complex formation. Both ligands react with iron(III) in a stepwise manner, forming stable complexes. With increasing temperature, the stability of the complexes increases. Changing the ionic strength of the solution and the concentration of H2SO4 equally affect the stability of the complexes. At the same time, moving from thiosemicarbazide to 1-formyl-3-thiosemicarbazide, the number of particles formed in the solution decreases, and the stability of the complexes decreases.