Determination of Stability Constants of 2-Hydroxy-1-Naphthalidene-2'-Methyl-4'-Nitro-Aniline Complexes with Y3+, La3+, Pr3+, Nd3+, Gd3+ and Dy3+

Department of Chemistry, Ramnarain Ruia College, Bombay-100 019

Manuscript received 2 January 1979, revised 24 January 1980, accepted 26 July 1980

"Potentiometric studies have been carried out on metal complexes of Y³⁺, La³⁺, Pr³⁺, Nd³⁺, Gd³⁺ and Dy³⁺ with 2-hydroxy-1-naphthalidene-2'-methyl-4'-nitroaniline. The dissociation constants (pK₁+pK₂) of the reagent and the formation constants of its metal complexes have been determined by Bjerrum method at 25°±0.1° and at an ionic strength 0.1M 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.