Extraction and Complexation of Trivalent Americium and Lanthanides by an Asymmetric Picolinic Acid-derived Tridentate N,O-hybrid ligand

The extraction and complexation of trivalent americium (Am) and lanthanides (Ln) using an asymmetric picolinic acid-derived tridentate N,O-hybrid ligand, 6-(dioctylcarbamoyl)picolinic acid (DOAPA), have been studied through both experimental and theoretical methods. DOAPA exhibits effective and fast extraction of Am(III) and Ln(III). The extraction is driven by favorable enthalpy change. Slope analysis, absorption spectroscopy and NMR titration indicate that both Am(III) and Ln(III) coordinate with DOAPA to form complexes of a 1 : 3 stoichiometry (metal to ligand). Meanwhile, luminescence and mass spectral studies suggest that three deprotonated tridentate DOAPA ligands (L