Influence of denticity and combined soft–hard strategy on the interaction of picolinic-type ligands with NpO₂⁺

Abstract

The denticity of the ligands and the combined hard–soft donor strategy work cooperatively in the coordination of NpO2+ with ligands.

Unusually Kinetically Inert Monocationic Neptunyl Complex with a Fluorescein-Modified 1,10-Phenanthroline-2,9-dicarboxylate Ligand: Specific Separation and Detection in Gel Electrophoresis

“…Both the Wiberg binding index (WBI), determined by an NBO analysis, and the results of a QTAIM analysis showed that the bonds between NpO 2 + and PDA were highly ionic (see the Supporting Information for details). This finding is in good agreement with the result reported by Ling et al The results of the CDA indicate unique molecular orbitals composed of the π orbital in Np=O, and f or d orbitals in Np significantly overlapping with the π orbital of PDA (Figures c and S5). For example, HOMO-18 (the 18th molecular orbital lower than HOMO) is composed of HOFO-5 of NpO 2 + (fragment orbital originated from the π orbital in NpO 2 + ) and HOFO-10 of PDA (originated from the π orbital); HOMO-10 is originated from the f orbital of NpO 2 + (HOFO-2) and the π orbital of carboxylate in PDA (HOFO-4).…”

“…Although the origin of the unique inertness of the NpO 2 + − L1 complex is not clear at this stage, it is unlikely that the electrostatic interaction is the predominant factor of this remarkably high kinetic stability. While Ling et al reported that the "hard-soft" donors in PDA provide thermodynamic stability to the neptunyl complex based on molecular orbital calculations, 39 an electronic factor of this kind would affect kinetic stability, as was found in our results.…”

“…The SDD, which treats the 60 core electrons (small core) as the potential to simplify the relativistic effect of heavy atoms, has often been used for transition metals , and UO 2 2+ complexes . The multiplicity ( S ) of the Np­(V)­O 2 + –PDA complex was set to 3. − Since no spin contamination was observed, ⟨ S 2 ⟩ in the ground state was equivalent to S ( S + 1), which is identical to the theoretical value. This suggested that the calculation was correctly performed.…”

Nanomechanics of Lignin–Cellulase Interactions in Aqueous Solutions

“…All geometry optimization and frequency calculations were carried out at the Hartree–Fock MP2 energy level by using the Gaussian 09 program . Two combined basis sets were employed to handle all atoms, one with the basis set 6-31+G­(d) for geometry optimization and frequency calculations and another with the larger basis set 6-311++G­(d,p) to refine energies using the single-point energy calculation . Frequency analysis was performed to confirm the optimized stationary point as a true minimum.…”

“…45 Two combined basis sets were employed to handle all atoms, one with the basis set 6-31+G(d) 46 for geometry optimization and frequency calculations and another with the larger basis set 6-311++G(d,p) to refine energies using the singlepoint energy calculation. 47 Frequency analysis was performed to confirm the optimized stationary point as a true minimum. The solvent effect of water was taken into account with the polarizable continuum model.…”