Two-electron/24-center (2e/24c) bonding in novel diradical pi-dimers

摘要

A series of diradical pi-dimers 2 with interesting pancake-shaped 2e/24c pi-pi bonding character were designed and investigated based on the famous phenalenyl (PLY) pi-dimer with 2e/12c pi-pi bonding character. The position of stronger interaction between two layers of radicals was found by the Wiberg bond index (WBI) maximum component. Further, the different contributions of the interaction energy were analyzed quantitatively by energy decomposition analysis (EDA). Among these new diradical pi-dimers, 2(180) has the smallest layer distance and the largest interaction between two layers of radicals. The unusual PLY analogues can provide new insights into the unique features of two-electron/multicenter (2e/mc) pi-pi bonding.