Novel Soft–Hard Donor Ligand, NTAamide, for Mutual Separation of Trivalent Actinoids and Lanthanoids

New reagent, N,N,N′,N′,N′′,N′′-hexaoctylnitrilotriacetamide (NTAamide(C8)), was synthesized and examined for actinoid and lanthanoid extractions. NTAamide(C8) has one N atom and three carbonyl oxygen atoms in the central frame, and may show hybrid bonds between hard O and soft N donors. It was found that NTAamide can extract Am(III) and Cm(III) from diluted HNO3 with small D(Ln). This result suggests that the N-donor makes stronger complexes with Am(III) and Cm(III) than Ln(III) at low HNO3.