Chromium Tricarbonyl and Chromium Benzene Complexes of Graphene, Their Properties, Stabilities, and Inter-Ring Haptotropic Rearrangements - A DFT Investigation

Abstract : The structures, electronic properties, stabilities, mechanisms, and activation barriers of the intramolecular inter‐ring haptotropic rearrangements (η6,η6‐IRHRs) of chromium tricarbonyl and chromium benzene complexes of graphene were modeled by DFT calculations. All of the above calculated characteristics are in good agreement with the experimental data for related complexes with ultralarge, large, and medium‐sized polyaromatic ligands (PALs). Generally η6,η6‐IRHRs between isomer complexes with organometallic groups (OMGs) in different positions in graphene ligand proceeds via η3‐transition states with activation barriers considerably lower (<25 kcal/mol) than those of the corresponding rearrangements in medium‐sized PALs (>30 kcal/mol). This could be explained by the reduction of electron density and the increase of electron mobility inside graphene molecules, which weaken metal–ligand bonds and facilitate rearrangements.