Piperidine- and 2-(p-tolyl)piperidine-derived DAPhen ligands: the aryl substituent unexpectedly suppresses the extraction efficiency

New piperidine- and 2-(p-tolyl)piperidine-derived phenanthroline diamides were synthesized, and their extraction efficiency toward Eu/Am pair was studied. The introduction of aryl substituent suppresses the extraction efficiency of such ligands from acidic solutions. The experimental results are in good agreement with DFT calculations.