Verifying the PCP-rule by five-center bond indices

Abstract

According to the recently discovered PCP-rule, the (stabilizing) energy-effect of the cyclic conjugation in the 5-membered ring of acenaphthylene- and fluoranthene-type polycyclic conjugated hydrocarbons increases with the number of phenyl–cyclopentadienyl (PCP) fragments present in the molecule. It is now shown that the validity of the PCP-rule is also supported by the 5-center bond indices, an independent quantitative theoretical measure of cyclic conjugation in 5-membered rings.

Keywords

• acenaphthylene-type hydrocarbons
• fluoranthene-type hydrocarbons
• PCP-rule
• multicenter bond index
• cyclic conjugation