Stability Constant of Pr(III), Nd(III) and Sm(III) Chelates with Some Substituted Pyrazolines

Abstract

The interaction of Pr(III), Nd(III) and Sm(III) metal ions with
3(2-hydroxy-3-iodo-5-methyl-phenyl)-1,5-diphenyl-pyrazoline
(ligand 1); 3(2-hydroxy-3-bromo-5-methyl-phenyl)-1-phenyl-5-( 4-
methoxy-phenyl)-pyrazoline (ligand 2) and 3(2-hydroxyc3-chloro-
5-methyl-phenyl)-5-(4-methoxy-phenyl)-pyrazoline (ligand 3) have
been investigated by pH-metric technique at 0.1 M ionic strength
at 27 ± 0.1 °C in 70% alcohol (methanol)-water mixture. The data
obtained were used to estimate the values of proton-ligand stability
constant (pk) and metal-ligand stability constants (log K). It is
observed that Pr(III), Nd(III) and Sm(III) metal ions formed 1 : 1
and 1 : 2 complexes with all the ligands.