Determination of stability constants of 2-hydroxy-1-naphthalidene-thiosemicarbazone complexes with Be2+, Y3+, Pr3+, Nd3+, Dy3+, Gd3+ and UO22+

Potentiometric studies have been carried out on metal complexes of Be2+, Y3+, Pr3+, Nd3+, Dy3+, Gd3+ and UO22+ with 2-hydroxy-1 naphthalidene-thiosemicarbazone. The proton-ligand dissociation constants (sub(p)Ksub(1) and sub(p)Ksub(2)) of the reagent and the formation constants of its metal complexes have been determined by Bjerrum's method at 25deg +- 0.1deg and at an ionic strength 0.1 M in 75:25 percent (v/v) dioxan-water medium. The validity of Born's relation was examined by studying the plot of Z2/r vs log k values of rare earth complexes of the ligand. (author)