Aromaticity and reactivity of acenes and phenylenes series

Abstract

The behavior of a homologous series of polycyclic aromatic hydrocarbons, the linear acenes, poses many unsolved problems. The interesting topic of debate in linear acenes is the evolution of aromaticity when going from the outer to inner rings. Anthracene, which has contrasting inner and outer rings, exhibits opposite results as to whether the central ring is the most or least aromatic according to some aromatic indexes. Recently, we defined the center ring is more aromatic than the outer one for anthracene by the combination method between asymmetric Kekulé structures (CMAK). This was also indicated by the index of deviation from aromaticity (IDA). The behavior of the aromaticity of the central ring for linear acenes was characterized by the CMAC. On the other hand, anthracene is protonated, adds bromine, and undergoes Diels-Alder reactions at the center ring. To study the reactivity and aromaticity for linear acenes and [n]phenacenes, we calculated the hydrogen addition energy for these compounds. In this conference, we will propose the reactivity points of these compounds from the hydrogen addition energy.