Extraction of actinyls: Systematic computational investigation on the complexation between actinyls and 2,2’- (Trifluoroazanediyl) bis (N,N’-dimethylacetamide)

Alkyl-substituted diglycolamides have been extensively studied for their ability to separate radioactive elements during the reprocessing of spent nuclear fuel. Herein, the stable structures, nuclear magnetic resonance (NMR) spectra, and interaction characteristics of the complexation between actinyls and 2,2’-(trifluoroazanediyl) bis (N,N’-dimethylacetamide) (CF 3 ABDMA) were elucidated through density functional theory (DFT) calculations. The predicted An–Oc bond lengths of ∼2.40 Å and An–N bonds of ∼2.80 Å confirm a stable tridentate coordination mode. Quantum theory of atoms in molecules and multiple interaction analysis methods were employed to elucidate the interaction mechanism between AnO₂ 2 ⁺ and ligands. The CF 3 ABDMA ligand coordinates to AnO₂ 2 ⁺ in a tridentate manner via the central nitrogen and two oxygen atoms, with actinide atoms exhibiting weak covalent interactions with these nitrogen and oxygen atoms. Energy decomposition analysis of electrostatic interaction magnitudes indicates the following trend for the complexes: UO₂ 2 ⁺(L)₂ (∼ –272 kcal mol -1 ) > NpO₂ 2 ⁺(L)₂ (∼ –270 kcal mol -1 ) > PuO₂ 2 ⁺(L)₂ (∼ –265 kcal mol -1 ). This trend is consistent with results from interaction analyses, where electrostatic interactions contribute to complex stabilization.