Synthesis and Characterization of an Unsymmetric Salicylaldimine Ligand Derived from 1-(2-Aminoethyl) piperazine and Investigation of Its Analytical Properties for the Extraction and Preconcentration of some Divalent Cations

Abstract

The synthetic, structural, spectroscopic and analytical properties of steric hindered Schiff-base ligand [N-(3,5-di-tert-butylsalicylaldimine)-1-(2-Aminoethyl) piperazine (HL)] and its mononuclear Cu(II), Co(II) and Ni(II) complexes are described. The new unsymmetric steric hindered Schiff base ligand containing a donor set of NONO was prepared by the reaction of 1-(2-Aminoethyl) piperazine with 3,5-di-tert-butylsalicylaldehyde. Certain metal complexes of this ligand were synthesized by treating an ethanolic solution of the ligand with an equimolar amount of metal salts. The ligand and its metal complexes were characterized by FT-IR, UV-Vis, H-1 NMR, elemental analysis, molar conductivity and magnetic susceptibility techniques. The reaction of this ligand in a 1: 2 mole ratio with metal acetate afforded mononuclear metal complexes. The molar conductivity (Lambda(M)) values of the metal complexes of Ni(II), Co(II) and Cu(II) were in the range of 6.4 to 9.8 Omega(-1) cm(2) mol(-1) at room temperature. Preconcentration and separation of Cu2+ from aqueous solution using N-(3,5-di-tert-butylsalicylaldimine)-1-(2-Aminoethyl) piperazine (HL) as a new extractant were studied. The extraction experiments were carried out at various pHs. While Cu2+ showed the highest extractability and selectivity at pH 7.0, extractions of Co2+ and Ni2+ were unsuccessful due to precipitate formation.