Reversible Photooxygenation of Anthracene Carboxyimide for Singlet Oxygen Formation: Mechanistic Study and Efficient Nitrite Detection

Abstract

Polycyclic aromatic endoperoxides are important sources of singlet oxygen ( 1 O 2 ) and their formation from polyacenes is well established. Anthracene carboxyimides are of particular interest as they exhibit excellent antitumor activity and possess unique photochemical properties. However, the photooxygenation of the synthetically versatile anthracene carboxyimide moiety has not been reported due to its competing [4 + 4] photodimerization reaction. Herein, we describe the reversible photo-oxidation of an anthracene carboxyimide. X-ray crystallographic analysis surprisingly revealed the formation of a racemic mixture of chiral hydroperoxides, rather than the expected endoperoxide. The photoproduct undergoes both photo-and thermolysis to form 1 O 2 . Activation parameters were derived for the thermolysis and the mechanisms of photooxygenation and thermolysis are discussed. The anthracene carboxyimide also showed high selectivity and sensitivity for nitrite anions in acidic aqueous media and possessed stimuli-responsive behaviour.

Carbohydrate‐Functionalized Anthracene Carboximides as Multivalent Ligands and Bio‐Imaging Agents

“…ACI s show anti‐cancer activity [36] and are used as starting materials for the synthesis of fluorescent dyes [35,37] . The photophysical properties of ACI s are tunable, depending on the substituent and this property finds applications in cell imaging, [38,39] sensing, [40–43] photodynamic therapy [44] and stimuli‐responsive materials [45,46] …”

“…[35,37] The photophysical properties of ACIs are tunable, depending on the substituent and this property finds applications in cell imaging, [38,39] sensing, [40][41][42][43] photodynamic therapy [44] and stimuli-responsive materials. [45,46] A study of the carbohydrate-conjugates of ACI is undertaken in the present study. Combining the photochemical and photophysical features of ACIs, through conjugation with biologically relevant carbohydrates, provides a facile route to monitor the specific carbohydrate-protein interactions, as well as, reducing the cytotoxicity of ACIs.…”

Porphyrin–anthracene covalent organic frameworks for sustainable photosterilization

“…Endoperoxides (EPOs) have interesting thermodynamic and photochemical properties and have been acknowledged as the most important chemical sources of 1 O 2 . 14,15 For example, polycyclic aromatic derivatives such as anthracene and naphthalene can capture 1 O 2 to form corresponding EPOs, and the obtained EPOs can further release 1 O 2 efficiently through the thermal cycloreversion reactions without side reactions. [16][17][18][19][20][21] It has also been reported that EPOs can produce 1 O 2 , which leads to cell death through a process similar to apoptosis.…”