2,6-Bis(1-alkyl-1H-1,2,3-triazol-4-yl)-pyridines: selective lipophilic chelating ligands for minor actinides

Starting from the promising minor actinides (MA) affinity showed by the water-soluble ligands (PyTri-polyols) with the 2,6-bis[1H-1,2,3-triazol-4-yl]-pyridine chelating unit, different attempts were made to functionalize the same N-3-donor set with alkyl chains in the 1-position of triazole nuclei to obtain novel lipophilic extractants endowed with comparable MA selectivity. Solubility in organic diluents was found to be the main limitation to the development of efficient lipophilic ligands, thus resulting in less efficient extractants with respect to their hydrophilic analogues and sometimes impairing the selectivity evaluation. Interestingly, the ethyl hexyl derivative (PTEH) showed adequate extraction capability and a MA selectivity comparable to that of the hydrophilic PyTri family.