Organometallic Chemistry of New Carbon Materials IV. Structure and Dynamic Behavior of Group 6 Metal Tricabonyl Complexes of Graphene and Perforated Graphene: A DFT Study

The mechanism of inter-ring haptotropic rearrangements (IRHR) was investigated by DFT for tricarbonyl η6-complexes of group 6 metals (M = Cr, Mo, W) of coronene (I-M), kekulene (II-M) and a model graphene (III-M). The computed η6,η6-IRHR activation barriers in the middle size PAHs I-M, and II-M were calculated to be substantially lower than in the case of complexes of relatively small size PAHs such as naphthalene chromium tricarbonyl (ΔG# ≈ 20-25 kcal mol–1 vs. ≈ 30 kcal mol–1). The barrier is further lowered in the case of the model graphene complex III-Cr (ΔG# ≈ 13 kcal mol–1). An even lower barrier is found for III-Mo (ΔG# ≈ 10 kcal mol–1), whereas it slightly increases for III-W (ΔG# ≈ 14 kcal mol–1).