Speciation of the ternary complexes formed between copper(II), salicylic acid and the amino acids serine, threonine, methionine and phenylalanine

Abstract

ABSTRACT In this work, we present the speciation of the ternary complexes formed between copper(II), salicylic acid (H2Sal) and the amino acids: serine (HSer, HL), threonine (HThr, HL), methionine (HMet HL) and phenylalanine (HPhe, HL) studied in aqueous solution at 25°C using 1.0 mol.dm−3 KNO3 as the ionic medium. The analysis of the potentiometric data using the least squares computational programLETAGROP indicates the formation of the ternary complexes Cu(Sal)(L)− and Cu(Sal)(L)(OH)2- were L indicates the amino acid under study. The species distribution diagrams as a function of pH were briefly discussed. The stability of the ternary complexes compared to the binary ones were evaluated in terms of ∆ log K”, log X and % R.S.