Selective complexation of uranium(III) over cerium(III) by 2,6-bis(5,6-dialkyl-1,2,4-triazin-3-yl)pyridines:: 1H NMR and X-ray crystallography studies

Addition of 2,6-bis(5,6-dialkyl-1,2,4-triazin-3-yl)pyridines (btp) to UI3 and CeI3 in anhydrous pyridine gave the 1:3 complexes [M(btp)(3)]I-3, the terdentate nitrogen ligand being completely selective for U-III over Ce-III, as shown by H-1 NMR competition experiments, crystal structures of analogous btp complexes of U-III and Ce-III revealed that the U-N bond distances are significantly shorter than the corresponding Ce-N distances.