▎ 摘　　要

We claim, on the basis of experimental and theoretical grounds, that pyrene cannot serve as a model for graphene for the purpose of edge-functionalization, as previously reported on the basis of direct Friedel-Crafts acylation of pyrene in polyphosphoric acid. Pyrene has been shown to undergo, at the most, Friedel-Crafts tetraacylation, at positions 1, 3, 6, and 8. Furthermore, pyrene has not undergone any Friedel-Crafts acylations at positions 2, 4, 5, 7, 9 and 10. We show, using DFT calculations (B3LYP/6-31G(d) and M06/6-31G(d)) that the regioselective Friedel-Crafts acylation of pyrene is kinetically controlled and is not thermodynamically controlled. The relative stabilities (Delta G(298), kJ/mol) of the sigma-complexes of monobenzoylpyrenes (sigma-BzPYH(+)) are 1 sigma-BzPYH(+) (0.0) >4 sigma-BzPYH(+) (37.5) >2 sigma-BzPYH(+) (53.1). The most stable sigma-complexes of dibenzoylpyrenes are also protonated at position 1 (1 sigma,3Z-, 1 sigma,4Z-, 1 sigma,6Z-, 1 sigma,8Z-, 1 sigma,9Z-and 1 sigma,10Z-Bz(2)PYH(+)). 2-BzPY and 2,7-Bz(2)PY, which are the most stable isomers in their respective series, are not formed in the Friedel-Crafts benzoylation of pyrene. The introduced electron-withdrawing acyl groups at positions 1, 3, 6, and 8 deactivate further acylation(s) of the pyrene ring system at ortho and peri positions, preventing the formation of, e.g., Bz(n)PY with n > 4. DFT calculations of bisanthene (BA) show that the preferred kinetically controlled products of mono- and dibenzoylations of bisanthene are 7-BzBA and 7,14-Bz(2)BA, respectively. The formation of neighboring peri and ortho acyl substituents at pyrene and bisanthene may be prohibited, due to considerable overcrowding.