Spectrophotometric Studies of Ternary Complexes of Erbium to Explore the Hyperchromic Effect with Various Ligands and their use in Microdetermination

Abstract

A comprehensive spectrophotometric study is undertaken for ternary complexes of higher rare earth element Erbium with ethylene diamine tetra acetic acid ( EDTA), hydroxyl ethylene diamine triacetic acid (HEDTA), trans 1, 2, cyclohexane diamine tetra acetic acid (CYDTA) and ethylene glycol bis (2-amino ethylene) N,N1,N11,N1 1 1 tetra acetic acid (EGTA) as primary ligand and the binary ligands used are Maltol, Tiron, Kojic acid and α-Picolinic acid. The ternary complexes shows hyperchromic effect as compare to primary complexes which is exploited to determine the stoichiometry of ternary complexes and it is found to be 1:1:1. The conditional stability constants (Ks1) are corrected using k H values of ligands. The order of stability with the series of ligands in different systems is deduced as EDTA and HEDTA: α Picolinic acid >Tiron> Kojic acid > Maltol and CYDTA and EGTA: α Picolinic acid > Kojic acid > Tiron > Maltol. The % increase in molar coefficients of mixed ligand complexes of Erbium is significant which can facilitates the analytical measurements for its micro determination.