<scp>Pentagon‐Containing</scp> Doublet Graphene Fragments with <scp>Edge‐Dependent</scp> Spin/Charge Distribution
Zongcheng Gong, Qin Xiang, Ke Li, Zhuofan Xu, Jinlian Hu, Yong Ni, Sota Sato, Zhe Sun
Abstract
Comprehensive Summary The synthesis of stable open‐shell hydrocarbon system comprising of pentagon defects and zigzag edges remains unexplored, which can be considered as model compounds for unraveling the spin‐localized states in graphene edges. With concise synthetic approaches, two π‐extended fluorenyl radicals were synthesized and isolated in their crystalline state. X‐ray crystallographic analysis and studies on the magnetic, optical and electrochemical properties of neutral and charged species have revealed an interesting edge‐dependence of the spin/charge distribution, that is, the spin and charge distribution shifted from the pentagon defects to the zigzag edges with the elongation of conjugation. Such phenomenon was unprecedented for hydrocarbon radicals and can be rationalized by the recovery of Clar Sextets in the dominant resonance structures. Remarkably, one of the radicals exhibited exceptional stability in air‐saturated solutions with the half‐life time up to 260 d, thus providing opportunities for the applications as electronic materials.