Study on the Equilibria of Chelate Formation and the Ion-association of Anionic Chelate of Germanium(IV) with 4-Nitrocatechol and 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium Cation

Resumo

The complex formation and the ion-association of the ion-pair formed between the anionic chelate of molybdenum(VI)‒3,5-dinitrocatechol (3,5-DNC) with the cation of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) in the liquid–liquid extraction system Mo(VI)‒3,5-DNC‒MTT‒H₂O‒CHCl₃ was studied by spectrophotometry. The optimum conditions for the chelate formation and extraction of the ion-associated complex Mo(VI)‒3,5-DNC‒MTT were established. The molar ratio of the components in the ion-associated complex Mo(VI)–3,5-DNC–MTT was determined by independent methods. The association process in aqueous phase and the extraction equilibria were investigated and quantitatively characterized. The following key constants of the processes were calculated: association constant, distribution constant, extraction constant and recovery factor. Based on this, a reaction scheme, a general formula and a structural formula of the complex were suggested.