Calix[4]tube: A Tobular Receptor with Remarkable Potassium Ion Selectivity


  • We thank the Engineering and Physical Sciences Research Council (EPSRC) for use of the mass spectrometry service at University of Swansea and, with the University of Reading, for funds for the image plate system. This work was supported by A. W. E. Aldermaston (fellowships for P. S. and P. D. S.).


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Even after three days the uptake of Li+, Na+, Cs+, and Rb+ ions by the novel calix[4]tube receptor 1 is not significant (<70%), whereas K+ ions are complexes within one hour. This remarkable selectivity for K+ ions is reminiscent of that of potassium channel proteins.