⁹⁹TcO₄⁻: Selective Recognition and Trapping in Aqueous Solution

Abstract

Too hot to handle: Unprecedented affinity and specificity for (99)TcO(4)(-) in aqueous solution was shown with the p-xylyl azacryptand in the hexaprotonated form. A crystal structure of the complex reveals how the anion fits within the cavity of the cage, and the formation of multiple H-bond interactions with protonated amino groups stabilize the adduct.