Adaptability of Electron-Localization Strategy for Achieving Planar Tetracoordination: Nitrogen versus Carbon

A case study has been performed on the adaptability of electron-localization strategy in designing clusters with planar tetracoordinate nitrogen (ptN) through the detailed comparison between ptN clusters NLi₃E⁺ (E=N, P, As) and their planar tetracoordinate carbon (ptC) counterparts CLi₃E (E=N, P, As). The results revealed that NLi₃E⁺ clusters possessed similar planar geometries to CLi₃E, which are both determined by the existence of a localized π bond. Nevertheless, NLi₃E⁺ clusters possess the obviously higher electronic, thermodynamic, and dynamic stabilities than CLi₃E clusters, as reflected by wider HOMO–LUMO gaps (4.58–4.68 eV versus 2.10–2.74 eV), the overall lower-lying positions on potential energy surfaces verified at the CCSD(T)/aug-cc-pVTZ level, and better rigidity during the molecular dynamic simulations at the PBE/DZVP level. Therefore, our results suggest that electron-localization strategy may be more suitable for designing the clusters, whose central atom possesses relatively higher electronegativity and more favours the localized bond. Due to the good stability, the cationic NLi₃E⁺ clusters designed in this work may be suitable for gas phase generation, mass-selection, and spectroscopic characterization.