An Air-Stable Organic Radical from a Controllable Photoinduced Domino Reaction of a Hexa-aryl Substituted Anthracene

Air-stable organic radicals and radical ions have attracted great attention for their far-reaching application ranging from bioimaging to organic electronics. However, because of the highly reactive nature of organic radicals, the design and synthesis of air-stable organic radicals still remains a challenge. Herein, an air-stable organic radical from a controllable photoinduced domino reaction of a hexa-aryl substituted anthracene is described. The domino reaction involves a photoinduced [4 + 2] cycloaddition reaction, rearrangement, photolysis, and an elimination reaction; H-1/C-13 NMR spectroscopy, high resolution mass spectrometry, single-crystal X-ray diffraction, and EPR spectroscopy were exploited for characterization. Furthermore, a photoinduced domino reaction mechanism is proposed according to the experimental and theoretical studies. In addition, the effects of employing push and pull electronic groups on the controllable photoinduced domino reaction were investigated. This article not only offers a new blue emitter and novel air-stable organic radical compound for potential application in organic semiconductor applications, but also provides a perspective for understanding the fundamentals of the reaction mechanism on going from anthracene to semiquinone in such anthracene systems.

Automated summary

A stable organic radical was synthesized through a controllable photoinduced domino reaction from hexa-aryl substituted anthracene. The mechanism of the photoinduced domino reaction was proposed based on experimental and theoretical studies, and the effects of using push and pull electronic groups in the controlled reaction were investigated. This research provides a new blue emitter and air-stable organic radical compound for potential applications in organic semiconductor devices while offering insights into the reaction mechanism from anthracene to semiquinone.