Synthesis and Characterization of Dibenzo[<i>a</i>,<i>f</i>]pentalene: Harmonization of the Antiaromatic and Singlet Biradical Character

Mesityl derivatives of the unknown dibenzopentalene isomer dibenzo­[a,f]­pentalene were synthesized. The molecular geometry and physical properties of dibenzo­[a,f]­pentalene were investigated. Dibenzo­[a,f]­pentalene combines a large antiaromatic and appreciable singlet open-shell character, properties not shared by well-known isomer dibenzo­[a,e]­pentalene.针对尚未明确表征的二苯并戊搭烯异构体——二苯并[a,f]戊搭烯（dibenzo[a,f]pentalene）的均三甲苯基（Mesityl）衍生物已完成合成制备。本研究对二苯并[a,f]戊搭烯的分子几何构型与物理性质展开了系统性探究。二苯并[a,f]戊搭烯兼具显著的反芳香性与可观的单重态开壳层特性，而这一独有性质并未在经典异构体二苯并[a,e]戊搭烯（dibenzo[a,e]pentalene）中体现。