Ab Initio Molecular Dynamics Study of Sodium NMR Chemical Shifts in the Methylamine Solution of [Na+ [2.2.2]cryptand Na–]

2020 
The sodium anion (Na–) was once thought to behave like a ‘genuine’ anion, with both the [Ne] core and the 3s valence shell interacting very weakly with their environments. In the present work, following a recent study of the surprisingly small quadrupolar line widths of Na–, NMR shielding calculations were carried out for the Na– /Na+ [2.2.2]cryptand system solvated in methylamine, based on ab-initio molecular dynamics simulations, followed by detailed analyses of the shielding constants. The results confirm that Na– does not act like a quasi-free ion that interacts only weakly with its surroundings. Rather, the filled 3s shell of Na– interacts strongly with its chemical environment, but only weakly with the ion’s own core and the nucleus, and it isolates the core from the chemical environment. As a consequence, the Na– ion appears in NMR experiments like a free ion.
    • Correction
    • Source
    • Cite
    • Save
    • Machine Reading By IdeaReader
    48
    References
    2
    Citations
    NaN
    KQI
    []