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7,8‐Dimethoxy‐3‐methyl‐1,10‐ethylenealloxazinium chloride (1a) was found to be a superior photooxidation catalyst among substituted ethylene‐bridged flavinium salts (R=7,8‐diMeO, 7,8‐OCH2O‐, 7,8‐diMe, H, 7,8‐diCl, 7‐CF3 and 8‐CF3). Selection was carried out based on structure vs catalytic activity and properties relationship investigations. Flavinium salt 1a proved to be robust enough for practical applications in benzylic oxidations/oxygenations, which was demonstrated using a series of substrates with high oxidation potential, i. e. 1‐phenylethanol, ethylbenzene, diphenylmethane and diphenylmethanol derivatives substituted with electron‐withdrawing groups (Cl or CF3). The unique capabilities of 1a can be attributed to its high photostability and participation via a relatively long‐lived singlet excited state, which was confirmed using spectroscopic studies, electrochemical measurements and TD‐DFT calculations. This allows the maximum use of the oxidation power of 1a, which is given by its singlet excited state reduction potential of +2.4 V. 7,8‐Dichloro‐3‐methyl‐1,10‐ethylenealloxazinium chloride (1 h) can be used as an alternative photocatalyst for even more difficult substrates. [ABSTRACT FROM AUTHOR]

Fluoroquinolone antibiotics are widely used in the treatment of various infectious diseases in humans and animals. These compounds are sensitive to light and undergo photodegradation in the solid and liquid state to form a number of products which have been identified by chromatographic and spectroscopic methods. The fluoroquinolones in aqueous and organic solvents are degraded on exposure to UV and sunlight by a number of pathways depending on the reaction conditions including medium, wavelength and intensity of light and duration of exposure of the solution. The present review deals with the identification of the photoproducts, photodegradation pathways and mechanism of photodegradation of various fluoroquinolones. [ABSTRACT FROM AUTHOR]

Keywords: Aerobic oxidation; Electron transfer; Photochemistry; Photoredox catalysis; Spectroscopy EN Aerobic oxidation Electron transfer Photochemistry Photoredox catalysis Spectroscopy 4283 4283 1 09/23/21 20210921 NES 210921 The B front cover picture b , prepared by Dr D. Prukala, illustrates ethylene-bridged 7,8-dimethoxyflavinium salt excited with blue light. Front Cover Picture: Robust Photocatalytic Method Using Ethylene-Bridged Flavinium Salts for the Aerobic Oxidation of Unactivated Benzylic Substrates (Adv. Aerobic oxidation, Electron transfer, Photochemistry, Photoredox catalysis, Spectroscopy. [Extracted from the article]

Review: 164 refs. [ABSTRACT FROM AUTHOR]