Similar linearity for all metal cations with ligand 1 was obtained.A regular absorbance increase was detected for Co2+ in the spectrophotometric titration with ligand 1 at 206 nm.
Because of their nearly insoluble nature in water under the abovementioned conditions very small quantities of 124-triazole ligand are sufficient to perform the spectrophotometric titrations according to Buschmann's method which is more appropriate for the determination of complex stability constants in aqueous solutions in comparison to fast and simple Valeur's method for which the ligand should be soluble in a proper solvent.
Before the spectrophotometric titration, carbonate-free potassium hydroxide solutions were prepared under a nitrogen atmosphere.
In this study, the pKa values of MNF and PNF have been determined precisely with spectrophotometric titrations in various MeCN-water binary mixtures.
Spectrophotometric titrations were carried out in the same conditions as for potentiometric titrations.
The spectrophotometric titrations were carried out in DMSO/[H.sub.2]O (5/95) solution with ligand and metal concentration of 1 x [10.sup.-5] M at 25 [+ or -] 1[degrees]C and ionic strength 0.1 M KCl.