Journal
TETRAHEDRON
Volume 63, Issue 19, Pages 4184-4189Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.tet.2007.02.105
Keywords
calixarenes; crown compounds; molecular recognition
Categories
Ask authors/readers for more resources
Di -ionizable calix[4]arene-1,2-crown-4 ethers in the cone conformation were synthesized and their conformation and regioselectivity verified by NMR spectroscopy. These new ligands exhibited high Ba2+ selectivity in competitive solvent extraction of alkaline earth metal cations from aqueous solutions into chloroform. The selectivity order was Ba2+>> Sr2+ >Ca2+> Mg2+ with Ba2+/Sr2+ selectivity exceeding 100. The ligands also exhibited high extraction ability for Pb2+ and for, Hg2+ in single species extraction. With variation of proton-ionizable groups, which are oxyacetic acid moieties and N-(X)sulfonyl oxyacetamide units with X=methyl, phenyl, 4-nitrophenyl, and trifluoromethyl, 'tunable' ligand acidity was obtained. (C) 2007 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available