Determination of Stability Constants of 2-Hydroxy1-Naphthalidene-2-6-Dimethylaniline Complexes with La3+, Y3+, Pr3+, Nd3+, Dy3+ and Gd3+

Department of Chemistry, Ramnarain Ruia College, Matunga, Bombay-400 019

Manuscript received 10 July 1981, revised 2 February 1982, accepted 23 May 1982

Potentiometric studies on metal complexes of La³⁺, Y³⁺, PO³⁺, Nd³⁺, Dy³⁺ and Gd³⁺ with 2-hydroxy-1-naphthalidene-2',6'-dimethylaniline have been carried out. The proton-ligand dissociation constants (pK₁ and pK₂) of the reagent and the formation constants of its metal complexes have been determined by Bjerrum's method at 25±0.1º and at an ionic strength 0.1M (NaCIO₄) in 75 : 25 percent (v/v) dioxane­water 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.