OLi4H3−: A planar tetracoordinate oxygen cluster with dynamic structural fluxionality

The recently reported series of molecular rotors containing planar hypercoordinate carbons is fascinating; their structural fluxionality is driven by multicenter delocalized bonds, similar to boron-based nano-rotors. Herein, we introduce a new cluster with unique fluxional behavior, OLi4H3−, containing a planar tetracoordinate oxygen (ptO) atom. Dynamic simulations show that the ligand Li and H atoms can rotate around the central ptO atom, exhibiting intriguing structural fluxionality even at room temperature. This rotational fluxionality is driven by the dominant electrostatic interaction between Li and O atoms and the supplemented delocalized covalent bonds in peripheral Li–H atoms. By possessing a vertical detachment energy of 4.25 eV, OLi4H3− is the first superhalogen mono-anion with a ptO center. As the global energy minimum, it is expected to be generated and characterized in the photoelectron detachment spectroscopy.