Diboryne Nanostructures Stabilized by Multitopic N-Heterocyclic Carbenes: A Computational Study.

Different families of nanomaterials produced from the stabilization of diboryne (B≡B) units by multitopic N-heterocyclic carbenes (NHCs), such as nanowires, nanorings, and nanotents, were studied by computational methods. Density functional theory calculations with and without periodic boundary conditions were applied to estimate the dependence of the electronic and thermochemical properties of different diboryne macromolecules with respect to the nature of the bridging ligand. Our results show that all diboryne nanostructures studied herein are viable candidates for synthesis. The Janus-type multitopic naphthobis(imidazolylidene) (5), anthrobis(imidazolylidene) (10), and pyracenetetrakis(imidazolylidene) (16) compounds are the best candidates for generating diboryne nanowires. A path to covalent organic frameworks, nanocages, and nanotubes from the optimized diboryne nanostructures is also described. Rather than just scientific curiosity, diboryne nanostructures emerge as interesting targets for the synthesis of main-group nanomaterials.