Anion Control Selectivity of Neutral N4-Type Schiff Base Extractants Towards Transition Metal Ions

Document Type: Research Article

Authors

Phase Equilibria Research Laboratory, Department of Chemistry, Faculty of Science, Zanjan University, P.O. Box 45195-313, Zanjan, I. R. IRAN

Abstract

Two N4-type Schiff base ligands named N,N'-bis(2-pyridylmethylidene)-1,2-diiminoethane (L1) and N,N'-bis(2-pyridylmethylidene)-1,3-diiminopropane (L2) have been synthesized by the reaction of pyridine-2-carbaldehyde with ethylenediamine and propylenediamine, respectively. The binding abilities of L1 and L2 in dichloromethane towards Cu2+, Cd2+, Co2+, Ni2+, Zn2+ and Pb2+ ions were evaluated by performing competitive extraction experiments on the mixtures containing theses ions from aqueous picrate and nitrate media as a function of the aqueous phase pH. The results show a pronounced selectivity of the ligands towards copper and cadmium ions among the tested metal ions. It is shown that the copper/cadmium selectivity of the ligands is profoundly influenced by the nature of anions accompanying the extracted complexes. In fact, the ligands are more efficient complexing agent for cadmium ions in the presence of nitrate and acetate anions, whereas this selectivity changes towards copper ions in the presence of picrate, perchlorate and thiocyanat ions.  

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[1] Rydberg J., Musikas C., Choppin G.R., "Principles and Practice of Solvent Extraction", MarcelDekker,New York(1992).

[2] Emadi D., Yaftian M.R., Rayati S.,N,N'-Bis(1'-Hydroxy -2'- Acetonaphthone) Propylenediamine: Synthesis, Extractive Properties and Use as an Ionophore in a Cu(II)-Selective Potentiometric Sensor, Turk. J. Chem., 31, p. 423 (2007).

[3] Rouhollahi A., Zolfonoun E., Salavati Niasari M., Effect of Anionic Surfactant on Transport of Copper(II) Through Liquid Memnrane Containing a New Synthesis Schiff Base, Sep. Purif. Technol., 54, p. 28 (2007).

[4] Shemirani F., Dehghan Abkenar S., Mirroshandel
A.A., Salavati Niasari M., Rahnama Kozania R., Absorption Spectrometry After Cloud-Point Extraction, Anal. Sci. 19, p. 1453 (2003).

[5] Fathi S.A.M., Yaftian M.R., Enrichment of Trace Amounts of Copper(II) Ions in Water Samples Using Octadecyl Silica Disks Modified by a Schiff Base Ionophore Prior to Flame Atomic Absorption Spectrometric Determination, J. Hazard. Mater., 164, p. 133 (2009).

[6] Oshima S., Hirayama N., Kubono K., Kokusen H., Honjo T., Ion-Pair Extraction Behavior of Divalent Transition Metal Cations as Charged Complexes with N,N'- Bis(2-Pyridylmethylidene) -1,2-Diiminoethane and its Analogues, Anal. Chim. Acta 441, p. 157 (2001).

[7] Oshima S., Hirayama N., Kubono K., Kokusen H., Honjo T., Structural Control of Schiff Base Ligands for Selective Extraction of Copper(II), Anal. Sci. 18, p. 1351 (2002).

[8] Oshima S., Hirayama N., Kubono K., Kukosen H., Honjo T., Ion-Pair Extaction Behavior of Divalent Metal Cations Using Neutral Di-Schiff Base Ligands Derived from 1,2-Cyclohexanediamine and O-Phenylenediamine, Talanta, 59, p. 867 (2003).

[9] Dietz M.L., Stepinski D.C., Anion Concentration-Dependent Partitioning Mechanism in the Extraction of Uranium Into Room-Temperature Ionic Liquids, Talanta, 75, p. 598 (2008).

[10] Yaftian M.R., EshraghiM.E., Hassanzadeh L., Extractive Properties on Tri-N-Octylphosphine Oxide Towards Thorium (IV) and Europium(III) Ions from Nitrate Media, Iran. J. Chem Chem. Eng., 22, p. 71 (2003).

[11] Takeda Y., Yasui A., Morita M., Katsuta Sh., Extraction of Sodium and Potassium Perchlorates with Benzo-18-Crown-6 Into Various Organic Solvents. Quantitative Elucidation of Anion Effects on the Extraction-Ability and Selectivity for Na+ and K+, Talanta, 56, p. 505 (2002).

[12] Yaftian M.R., Rayati S., Safarbali R., Torabi N., Khavasi H.R., Tansition Met. Chem., 32, p. 374 (2007).

[13] Pilehvari Z., Yaftian M.R., Rayati S., Parinejad M., A Novel Wire-Type Lead-Selective Electrode Based on Bis (1'-Hydroxy -2'- Acetonaphthone) -2,2'-Diiminodiethylamine, Ann. Chim., 97, p. 747 (2007).

[14] Skoog D.A., West D.M., Holler F.J., "Fundamentals of Analytical Chemistry",Saunders,New York(1992).