151377-74-1Relevant articles and documents
Photoinduced C-F bond cleavage in some fluorinated 7-amino-4-quinolone- 3-carboxylic acids
Fasani,Barberis Negra,Mella,Monti,Albini
, p. 5388 - 5395 (1999)
The photochemistry of some fluorinated 7-amino-4-quinolone-3-carboxylic acids used in therapy as antibacterials and known to be phototoxic has been investigated in water. All of them undergo heterolytic defluorination, and this appears to be a path for the generation of aryl cations in solution. 6- Fluoro derivatives such as norfloxacin (Φ(dec) = 0.06) and enoxacin (Φ(dec) = 0.13) give the corresponding phenols. Insertion of an electron-donating substituent makes defluorination inefficient; thus, ofloxacin, an 8-alkoxy derivative, is found to be rather photostable (Φ(dec) = 0.001) and reacts in part via a process different from defluorination (degradation of the N-alkyl side chain). With a 6,8-difluoro derivative, lomefloxacin, the reaction is more efficient (? = 0.55) and selective for position 8. Contrary to the previous cases, the aryl cation undergoes insertion in the neighboring N- ethyl group rather than solvent addition (a carbene-like chemistry). With all of the above fluoroquinolones an intensive triplet-triplet absorption is detected and is quenched by sulfite (k(q) = (1-5) x 108 M-1 s-1). Under this condition, reductive defluorination via the radical anion takes place. The relation of the above chemistry to the phototoxicity of these drugs is commented upon briefly.
Visible light-driven photocatalytic degradation of organic pollutants by a novel Ag3VO4/Ag2CO3 p–n heterojunction photocatalyst: Mechanistic insight and degradation pathways
Sun, Haibo,Qin, Pufeng,Wu, Zhibin,Liao, Chanjuan,Guo, Jiayin,Luo, Shuai,Chai, Youzheng
supporting information, (2020/04/28)
In the field of photocatalysis, the construction of a heterojunction system with efficient charge separation at the interface and charge transfer to increase the photocatalyst performance has gained considerable attention. In this study, the Ag3VO4/Ag2CO3 p–n heterojunction is first synthesized using a simple co-precipitation method. The composite photocatalyst with a p-n heterojunction has a strong internal electric field, and its strong driving force can effectively solve the problem of low separation and migration efficiency of photogenerated electron-hole pairs. The optimized Ag3VO4/Ag2CO3 composite can effectively degrade organic pollutants (rhodamine b (RhB), methylene blue (MB), levofloxacin (LVF), and tetracycline). More specifically, the Ag3VO4/Ag2CO3 photocatalyst with a 1:2 mass ratio (VC-12) can remove 97.8percent and 82percent of RhB and LVF within 30 and 60 min, respectively. The LVF degradation rate by VC-12 under visible light irradiation is more than 12.8 and 21.51 times higher than those of pure Ag3VO4 and Ag2CO3, respectively. The excellent photocatalytic activity of the Ag3VO4/Ag2CO3 hybrid system is mainly attributed to the internal electric field that forms in the Ag3VO4/Ag2CO3 p–n heterojunction system, the photogenerated electron hole pairs that separate and facilely migrate, and the specific surface area of VC-12 that is larger than that of the monomer. In addition, the degradation efficiency of VC-12 did not decline significantly after four cycles. In this study, the photocatalytic mechanism for Ag3VO4/Ag2CO3 photocatalysts is explored in detail based on the energy band analysis results, trapping experiment results, and electron spin resonance spectra. Finally, the LVF degradation products are analyzed by liquid chromatography–mass spectrometry, and the potential LVF degradation pathway is identified. The experiments performed in this research therefore lead to new motivation for the design and synthesis of highly efficient and widely applicable photocatalysts for environmental purification.
Photodegradation products of levofloxacin in aqueous solution
Yoshida,Sato,Moroi
, p. 601 - 606 (2007/10/02)
The photodegradation of levofloxacin (DR-3355, CAS 100986-85-4), the S-(-)-isomer of ofloxacin, was investigated. Levofloxacin in aqueous solution was exposed to near ultraviolet light (peak wavelength 352 nm) for 16 h at room temperature. Nine degradation products (P-2-P-10) were isolated from the reaction mixture by preparative high performance liquid chromatography. The structures of these compounds were deduced from their NMR, MS, UV and IR spectra and optical rotations. The elucidated structures showed that all of these degradation products were analogues altered at the N-methylpiperazine moiety of levofloxacin.
