Two‐layer molecular rotors: A zinc dimer rotating over planar hypercoordinate motifs

Abstract

Multi‐layer molecular rotors represent a class of unique combination of topology and bonding, featuring a barrier‐free rotation of one layer with respect to other layers. This emerging fluxional behavior has been found in a few doped boron clusters. Herein, we strongly enrich this intriguing family followed by an effective design strategy, summarized as essential factors: i) considerable electrostatic interactions originated from a strong charge transfer between layers; ii) the absence of strong covalent bonds between layers; and iii) fully delocalized σ/π electrons from at least one layer. We found that planar hypercoordinate motifs consisting of monocyclic boron rings and metals with σ + π dual aromaticity can be regarded as one promising layer, which can support the suspended X2 (X = Zn, Cd, Hg) dimers. By detailed investigations of thermodynamic and kinetic stabilities of 60 species, eventually, MB7X2− and MB8X2 (X = Zn, Cd; M = Be, Ru, Os; Be works only for Zn‐based cases) clusters were verified to be the global‐minimum two‐layer molecular rotors. Especially, their electronic structure analyses vividly confirm the practicability of the electronic structure requirements mentioned above for designing multi‐layer molecular rotors.

Density Functional Study to Investigate the Ability of (ZnS)n (n = 1–12) Clusters Removing Hg0, HgCl, and HgCl2 via Electron Localization Function and Non−Covalent Interactions Analyses

“…The structure with the lowest energy is the global minimum (GM) structure of the cluster. The PBE0/def2−TZVP method [ 38 , 39 ] has been widely used in zinc compounds [ 40 , 41 , 42 , 43 , 44 ]. The structures of (ZnS) n Hg, (ZnS) n HgCl, and (ZnS) n HgCl 2 clusters have been obtained based on the GM structures of (ZnS) n .…”