New heavy metal ion-selective macrocyclic ligands with mixed-donor atoms and their extractant properties

Abstract

Synthetic procedures for new macrocyclic diamides with N₂S₄O₃- and N₂S₅O₃-donors were given. The corresponding macrocyclic ligands were prepared by reaction of NaBH₄ with the macrocyclic diamides in the presence of boron triflouride ethyl etherate in dry tetrahydrofuran. The solvent extraction method was used to evaluate metal-ion binding properties of the new ligands. The values of the extraction constants (log K _ex) and the complex compositions were determined for the extracted complexes. The solvent extraction experiments suggested that the reduced N₂S₅O₃-donor macrocycle has Ag⁺ selectivity compared to Pb²⁺, Co²⁺, Ni²⁺, Mn²⁺, and Cd²⁺ for chloroform as organic solvent.

Keywords:

• Extraction constant
• Mixed-donors
• Macrocyclic ligand
• Extractability
• Selective extraction

Acknowledgment

This study was supported by the Research Fund of Karadeniz Technical University, Project no: 2004.111.002.6 (Trabzon/Turkey).