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Time‐Resolved Near Infrared Studies on Singlet Oxygen Production by the Photosensitizing 2‐Arylpropionic Acids *
Author(s) -
Peña Daniel,
Martí Cristina,
il Santi,
Martínez Luis A.,
Miranda Miguel A.
Publication year - 1997
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1997.tb01930.x
Subject(s) - chemistry , naproxen , singlet oxygen , ketoprofen , nabumetone , carboxylate , acetonitrile , photochemistry , deprotonation , singlet state , medicinal chemistry , nonsteroidal , stereochemistry , organic chemistry , oxygen , chromatography , excited state , medicine , ion , physics , alternative medicine , pathology , nuclear physics , pharmacology
— Time‐resolved near infrared emission studies have been carried out on a series of nonsteroidal anti inflammatory 2‐arylpropionic acids, in order to assess their ability to photosensitize the production of singlet molecular oxygen O 2 (1Δ g ). Benoxaprofen, naproxen, tiaprofenic acid, suprofen, ketoprofen and carprofen showed quantum yields for this process (φΔ) in the range 0.2‐0.7 in acetonitrile. Deprotonation of the propionic acid moiety in mixtures of acetonitrile‐ethanol (4:1) basified with KOH produced a systematic decrease in φ Δ for all compounds with the exception of naproxen. This effect was even more dramatic in D 2 O‐based phosphate buffer, where no singlet oxygen could be detected for benoxaprofen, ketoprofen or carprofen. The above results are consistent with the occurrence of competing photochemical reactions of 2‐arylpropionic acids in different media and particularly with the enhanced photodecarboxylation from the carboxylate anions.