Selective Liquid-Liquid Extraction of Fe(II) and Cd(II) Using N,N’-Pyrazole Bidentate Ligands with Theoretical Study Investigations

Five bidentate pyrazole ligands L1–L5 have been prepared in good yield by condensation of one equivalent of 3,5-dimethyl-1H-pyrazol-1-yl)methanol 1 and 1H-pyrazol-1-yl) methanol 2 with one equivalent of starting material pyrazole derivatives, in refluxed acetonitrile during 4 hours. These compounds were used for extracting different metal ions from aqueous solution using liquid-liquid extraction methodology. The preliminary results show that the new materials present high extraction affinity toward iron and cadmium; for example the compounds L2 and L4 gave a high extraction rate with Fe(II) about 86.03% and 61.55%, respectively, compounds L1 and L5 gave a good extractive affinity for Cd(II) about 56.66% and 42.00%, respectively. For mechanistic discussions a theoretical study has been reported.