CATALYTIC EFFECTS ON KINETICS OF THE STONE-WALES ISOMERIZATIONS: COMPUTATIONS OF THE N AND CN CASES

摘要

The Stone-Wales rearrangement has for long time been considered as a plausible, albeit hypothetical, mechanism for fullerene annealing and isomerizations. In the view of recently applied catalyst, KCN, for incorporation of noble gases in fullerenes, CN radical is studied here computationally as a possible catalytic species acting in kinetics of the Stone-Wales fullerene transformation. The computations are performed on the PM3 optimized bowl-shaped model C_(34)H_(12) to which the CN radical is attached by its C or N atom. The activation energies are evaluated at the UPM3, UHF/6-31G*, UB3LYP/6-31G*, ROB3LYP/6-31G*, ROHF/6-31G**, and ROB3LYP/6-31G** levels. However, the reduction of the kinetic barrier owing to the catalyst action is rather modest so that a free N atom, neutral or charged, still remains a more efficient option. Small amounts of nitrogen are indeed always present during fullerene synthesis, especially from He gas. However, effects of charged CN species and possibly also of potassium atom should similarly be checked.