Si6C18: A bispentalene derivative with two planar tetracoordinate carbons

Abstract

Abstract Here we show that substituting the ten protons in the dianion of a bispentalene derivative (C 18 H 10 2− ) by six Si 2+ dications produces a minimum energy structure with two planar tetracoordinate carbons (ptC). In Si 6 C 18 , the ptCs are embedded in the terminal C 5 pentagonal rings and participate in a three‐center, two‐electron (3c‐2e) Si‐ptC‐Si σ‐bond. Our exploration of the potential energy surface identifies a triphenylene derivative as the putative global minimum. Nevertheless, robustness to Born–Oppenheimer molecular dynamics (BOMD) simulations at 900 and 1500 K supports bispentalene derivative kinetic stability. Chemical bonding analysis reveals ten delocalized π‐bonds, which, according to Hückel's 4 n + 2 π‐electron rule, would classify it as an aromatic system. Magnetically induced current density analysis reveals the presence of intense local paratropic currents and a weakly global diatropic current, the latter agreeing with the possible global aromatic character of this specie.