Fig. 1: Resonance models for the organoactinide compounds.
From: Actinide inverse trans influence versus cooperative pushing from below and multi-center bonding
Panels a and b represent proposed structures for the \({{{{{{{\rm{{:}}}N}}}}}}{({{{{{{{{\rm{R}}}}}}}}}^{{{{{{{{\rm{a}}}}}}}}})}_{3}{-}{{{{{{{\rm{An}}}}}}}}{-}{{{{{{{\rm{Y}}}}}}}}\) and \({{{{{{{\rm{X}}}}}}}}{-}{{{{{{{{\rm{U}}}}}}}}}^{{{{{{{{\rm{VI}}}}}}}}}{({{{{{{{{\rm{R}}}}}}}}}^{{{{{{{{\rm{b}}}}}}}}})}_{3}{-}{{{{{{{\rm{O}}}}}}}}\) compounds, respectively. Actinides emphasized by green color. The trans-interaction is emphasized by purple color, and blue is used for better readability of the panels. The purple arrow represents the proposed axial electronic stabilization via ITI by the Namine in the TRENTIPS ligand. Panels c and d show the dominant Lewis structures 1 and 2 for \({({{{{{{{{\rm{R}}}}}}}}}^{{{{{{{{\rm{a}}}}}}}}})}_{3}{{{{{{{\rm{N}}}}}}}}{-}{{{{{{{{\rm{U}}}}}}}}}^{{{{{{{{\rm{VI}}}}}}}}}{-}{{{{{{{\rm{N}}}}}}}}\) and \({{{{{{{\rm{Me}}}}}}}}{-}{{{{{{{{\rm{U}}}}}}}}}^{{{{{{{{\rm{VI}}}}}}}}}{({{{{{{{{\rm{R}}}}}}}}}^{{{{{{{{\rm{b}}}}}}}}})}_{3}{-}{{{{{{{\rm{O}}}}}}}}\) compounds analyzed by natural bond orbital (NBO) natural resonance theory (NRT). Panels e and f show isosurfaces (±0.03 atomic units in red/blue) of selected natural localized molecular orbitals (NLMOs, from DFT/B3LYP calculations) for \({({{{{{{{{\rm{R}}}}}}}}}^{{{{{{{{\rm{a}}}}}}}}})}_{3}{{{{{{{\rm{N}}}}}}}}{-}{{{{{{{{\rm{U}}}}}}}}}^{{{{{{{{\rm{VI}}}}}}}}}{-}{{{{{{{\rm{N}}}}}}}}\) and \({{{{{{{\rm{Me}}}}}}}}{-}{{{{{{{{\rm{U}}}}}}}}}^{{{{{{{{\rm{VI}}}}}}}}}{({{{{{{{{\rm{R}}}}}}}}}^{{{{{{{{\rm{b}}}}}}}}})}_{3}{-}{{{{{{{\rm{O}}}}}}}}\), respectively, with the corresponding AO contributions (some AO hybrids are labeled with subscripts; e.g., 2sp indicates a 2s-rich hybrid with secondary 2p contributions). Hydrogens are omitted from the structures for clarity.
