Spectrophotometric Study in Complexation of Samarium (III) with 3-(2-Hydroxy-3-Sulfo-5-(Chlorophenylhydrazo) Pentane-2,4-Dione in the Presence of Surfactants
Aim. To explore the interaction of samarium with 3-(2-hydroxy-3-sulfo-5-(chlorophenylhydrazo) pentane-2,4-dione in the presence and in the absence of a cetylpyridinium surfactant (cetylpyridinium chloride CPCl, cetylpyridinium bromide CPBr, cetyltrimethylammonium bromide CTABr). Methods. The conductivity of the complexes was studied by conductometric titration. We used the curve intersection method to calculate the stability constant of the complex. Results. The stability constants of homogeneous and mixed ligand complexes of samarium (III) were calculated. According to calculations lgb<sub>1</sub>(SmR)=7,26±0,05; lgb<sub>1</sub>(SmR-CPCl)=9,24±0,04; lgb<sub>1</sub>(SmR-CPBr)=9,41±0,05; lgb<sub>1</sub>(SmR- CTABr)=9,88±0,04. Conclusions. Comparison of the electrical conductivity of homogeneous and mixed ligand complexes of samarium (III) at pH 6 shows that mixed-ligand complexes are more stable than the binary ones.