Angew. Chem. Int. Ed.http://doi.org/fz59tg (2012)

Technetium-99 is a long-lived radioactive isotope with a half-life of more than 200,000 years and, as the pertechnetate ion (TcO4), is a notable component of spent nuclear fuel. The high solubility of this oxoanion in water means that it can spread quite widely in the environment. The development of molecules that can selectively trap this hazardous species could lead to materials that extract it from nuclear-waste streams. Owing to its radioactivity, much academic research on the design of receptors for TcO4 has used the structurally similar perrhenate ion (ReO4) as an analogue. Those studies that have focused on TcO4 itself have not typically been done in water.