A Rare and Exclusive Endoperoxide Photoproduct Derived from a Thiacalix[4]arene Crown‐Shaped Derivative Bearing a 9,10‐Substituted Anthracene Moiety

Abstract

A rare and exclusive endoperoxide photoproduct was quantitatively obtained from a thiacalix[4]arene crown-shaped derivative upon irradiation at λ=365 nm; the structure was unambiguously confirmed by (1) H/(13) C NMR spectroscopy and X-ray crystallography. The prerequisites for the formation of the endoperoxide photoproduct have also been discussed. Furthermore, the photochemical reaction rate could be greatly enhanced in the presence of the thiacalix[4]arene platform because it served as a host to capture oxygen.

An Unprecedented Photochemical Reaction for Anthracene‐Containing Derivatives

“…The photolysis reaction prerequisites were also discussed. According to our recent work and that of others, anthracene‐containing derivatives ( R1 , R2 , R3 , R4 and R5 ; Figure ), bearing different linkers between the anthracene moiety and a thiacalix[4]arene or other platform, only gave the conventional photodimerization or endoperoxide photoproducts upon UV irradiation. To our knowledge, there are no reports relating to such a photolyzable photochemical phenomenon based on anthracene‐containing derivatives as observed herein.…”

“…The opportunity for the cycloaddition of 1 O 2 on the electron‐rich carbon atoms of the central anthracene ring was decreased. On the other hand, the photochemical reaction rate could be greatly enhanced in the presence of thiacalix[4]arene platform because it served as a host to capture oxygen . Finally, the whole photolysis process is proposed as shown in Scheme .…”

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

“…Normally, anthracene and its derivatives prefer to react with oxygen under UV irradiation to afford EPOs, which further undergo a thermolysis or decomposition process with an uncontrollable reaction pathway. − Here, to investigate the electronic effect on the kinetics of the photoinduced domino reaction, these hexa-aryl substituted anthracenes, compounds 2 , were irradiated (λ ex = 365 nm, 6 W) in CDCl 3 at 25 °C and tracked by 1 H NMR spectroscopy.…”

“…Anthracene is a representative member of the polycyclic aromatic hydrocarbons (PAHs), which is receiving great attention because of their potential application in both academic and industrial fields, e.g., organic semiconductors , and optical information storage. , Unlike common PAH members, such as pyrene or perylene, the distinguishing characteristics of anthracene and its homologues are that they prefer to undergo a photoinduced [4 + 2] cycloaddition reaction with singlet oxygen ( 1 O 2 ) under irradiation, leading to endoperoxides (EPO). , This further evolves into a competition between reconversion (to the parent acene) and decomposition. − Thus, anthracenes can be widely utilized as high-efficiency trapping-releasing singlet oxygen agents for potential applications as high-performance photodynamic therapy agents (PDT), fluorescent probes, and molecular switches, as well as in lithography …”

“…The mechanism of the photoinduced cycloaddition reaction of anthracene with oxygen has been exhaustively studied. , Typically, photooxygenation of anthracenes occurs to give the corresponding 9,10-endoperoxides (EPOs), which further reform the parent anthracenes and undergo release of singlet oxygen (O 2 (a 1 Δ g )) through a cycloreversion process (Scheme ). , On the other hand, photolysis of EPO can lead to decomposition to quinones by a multistep cleavage process.…”