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]I3, the terdentate nitrogen ligand being completely selective for UIII over CeIII, as shown by 1H NMR competition experiments; crystal structures of analogous btp complexes of UIII and CeIII revealed that the U–N bond distances are significantly shorter than the corresponding Ce–N distances.