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

Abstract

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; 1H/13C 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.

Syntheses and crystal structures of a nitro–anthracene–isoxazole and its oxidation product

“…A search in the same database for the 10-hydroxy anthrone fragment resulted in 59 hits, of which 10 structures had an aromatic ring at the 10-position, namely refcodes COBWEY (Barker et al, 2019), DULVUB (Skrzat & Roszak, 1986), ELULII (Stepovik et al, 2015), EVETIL (Mao et al, 2021), JAYPAA (Roszak et al, 1990), MOTJIQ (Chen et al, 2015), MOTKEN (Chen et al, 2015), QAJPUQ (Forensi et al, 2020), SAMNEC (Hoffend et al, 2013) and WOKYIH (Pullella et al, 2019). The anthrone unit in these 10 structures are either essentially planar or in a shallow boat conformation.…”

Photochemical Dimerization of Plakinidine B Leads to Potent Inhibition of the E3 Ubiquitin-Protein Ligase CBL-B

“…After 2 h irradiation with white light, ABDA was completely consumed and partially converted to two γ-lactone derivatives 4 and 5 (Figure D and S11). It is reasonable to hypothesize that 4 and 5 were formed through a similar anthracene endoperoxide degradation pathway as previously described with the participation of a key zwitterion intermediate a (Figure S12). Finally, the 2 -sensitized photosynthesis of singlet oxygen ( 1 O 2 ) was confirmed by indirect detection and quantification of 1 O 2 by electron paramagnetic resonance (EPR) using a 1 O 2 -specific spin trap 2,2,6,6-tetramethyl-4-piperidone (4-Oxo-TEMP) .…”