Americium(iii) and europium(iii) solvent extraction studies of amide-substituted triazine ligands and complexes formed with ytterbium(iii)

Abstract

4-Amino-bis(2,6-(2-pyridyl))-1,3,5-triazine L⁴ and several, amide derivatives with hydrophobic alkyl substituents have been synthesised. Solvent extraction studies carried out on Am(III) and Eu(III) with L⁴ and its amide derivatives in synergistic combination with α-bromodecanoic acid, show that these ligands can selectively extract actinides with respect to lanthanides. The structures of [H₂L⁴]·2Cl·2.5H₂O and two amide derivatives have been determined and show respectively the trans, trans; cis, cis; and cis, trans conformations of the adjacent aromatic rings. These observed conformations are in agreement with the results of quantum mechanics calculations on L⁴ and its protonated derivatives. The structures of two Yb complexes with amide derivatives are also reported with stoichiometry [Yb(L)(NO₃)(H₂O)₄]·2NO₃·0.5H₂O and [Yb(L)(NO₃)₃(H₂O)]·2MeCN and show the metal in 9 coordinate environments.