Sorting out which radioactive isotope of an element can be used.
Sorting out which radioactive isotope of an element can be used, for example, as a probe in medical diagnostics is one thing, but then being able to selectively extract that isotope is another problem altogether. The only radioactive rare earth element that is man-made - promethium - has an isotope (147Pm) that is important as an X-ray source for bone mineral determination.
Researchers in China have for the first time found a way of selectively recognising and extracting 147Pm from an acidic solution of Pm(iii) ions.
They have made a molecule with a cavity that is the perfect size to accommodate this isotope. This three-legged analogue of a macromolecule can accommodate a number of different sized lanthanide ions, but when it came to extracting them from solution, 147Pm was by far the most popular.
Weisheng Liu from Lanzhou University explains the significance of his tripodal recognition molecule, ’this result provides new information for [the] design of excellent separation reagents of promethium and other rare earth elements’.
W Liu et al., Dalton Trans., 2004, 640 <MAN>b312381b</MAN>