Selective and efficient tripodal receptors for competitive solvent extraction and bulk liquid membrane transport of Hg2+
ABSTRACT A series of tripodal receptors that are different from each other in their end groups were synthesized. The extraction ability and the transport rate of these receptors were evaluated for transition metal ions (Fe(3+), Ni(2+), Cu(2+), Zn(2+) and Hg(2+)). The receptor bearing pyridyl nitrogens extracted Hg(2+) from a buffered aqueous medium containing a mixture of metal ions and transported it into an organic phase with a complete selectivity over the other metal ions. This receptor was effectively used for transporting Hg(2+) from aqueous buffered source phase to aqueous receiving phase through a chloroform membrane.
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ABSTRACT: The clear connection between molecular structures of N-substituted picolinamides and extraction behaviour has been rationalized by highlighting the relationship between intramolecular hydrogen bonding and rotational isomerism. To this aim aromatic pyridine-2,6-dicarboxamides 1a-1c with N-substitution and their analogues 3a and 3b containing intramolecular hydrogen bonds were designed and synthesized. The results from the liquid-liquid extraction towards some representative transition metal picrates including Ag+, Hg2+, Pb2+, Cd2+, Zn2+, Cu2+, Co2+ and Ni2+ salts demonstrated that the higher selectivity and efficiency towards Hg2+ (88.6-95.4%) over other metal cations stem mainly from N-substitution via disruption of intramolecular H-bonding. X-ray structural analysis, and ordinary and variable-temperature proton and carbon NMR experiments provided supporting information for expounding the difference in extraction ability among these ligands, particularly the importance of N-substitution that leads to the formation of rotamers affecting the extraction process.RSC Advances 01/2014; 4(56):29702. DOI:10.1039/C4RA02030H · 3.71 Impact Factor
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ABSTRACT: In this work, three types of molecularly imprinted polymers (MIP) containing atenolol selective sites were prepared by the methods of bulk polymerization, precipitation polymerization and suspension polymerization in silicon oil. Then, the MIP particles were used as the carrier elements in a bulk liquid membrane (BLM). Atenolol transport capabilities of different MIPs were compared with those of their relevant non imprinted polymers (NIP). It was shown that both nano- and micro-sized MIPs, obtained from suspension polymerization in silicon oil and precipitation polymerization, respectively, could transport atenolol more effective than the relevant NIPs. However, the nano-sized MIP was better than the micro-sized MIP for transportation of atenolol. Furthermore, the bulky MIP was not proper atenolol carrier in the BLM, since its transportation characteristic was similar to that of its relevant NIP. Moreover, the selectivity of the BLM containing different kinds of the MIPs obeyed the order of nano-MIP > micro-MIP > bulky MIP. The nano-MIP was adopted as the best atenolol carrier among the tested MIP-based carriers and then the effect of different factors on its transportation efficiency was evaluated. A kinetic model was proposed for the transportation of atenolol through the nano-MIP based BLM. It was found that the extraction of atenolol from the source to the membrane control the separation rate.Separation and Purification Technology 04/2012; 90:83–91. DOI:10.1016/j.seppur.2012.02.005 · 3.07 Impact Factor
European Journal of Pain Supplements 09/2011; 5(1):135-136. DOI:10.1016/S1754-3207(11)70463-1