Study of Complex Formation Between 18-Crown-6 and Pb2+, Tl+ and Cd2+ Cations in Binary Aqueous/Non-aqueous Solvents Using Polarographic Techniques (DPP and SWP) |
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| Authors: | Gholamhossein Rounaghi Mahmood Chamsaz Azizollah Nezhadali |
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| Institution: | (1) Department of Chemistry, Ferdowsi University of Mashhad, Mashhad, Iran |
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| Abstract: | The complexation of Pb2+, Tl+ and Cd2+ cationsby 18-crown-6 was studied in water/propanol (H2O/PrOH),water/acetonitrile (H2O/AN) and water/dimethylformamide(H2O/DMF) binary systems at 20 °C using squarewave polarography (SWP) and differential pulse polarography (DPP).It was confirmed that the stoichiometry of each of the complexes formed between 18C6 and the respective cations is 1 : 1. The formation constants of the complexes were found to increase with increasing concentration of the non-aqueous solvent. In all cases, a stability order of Pb2+ > Tl+ > Cd2+ was observed. In general,the stabilities of individual complexes were found to decrease as the binary solvent mixture varied from H2O/AN to H2O/PrOH to H2O/DMF. |
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| Keywords: | 18-Crown-6 lead(II) thallium(I) cadmium(II) Mixed-solvent Polarography |
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