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AN ESR STUDY OF THE VISIBLE LIGHT PHOTOCHEMISTRY OF GILVOCARCIN V
Author(s) -
ALEGRIA ANTONIO E.,
KRISHNA C. MURALI,
ELESPURU ROSALIE K.,
RIESZ PETER
Publication year - 1989
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.1751-1097.1989.tb04104.x
Subject(s) - chemistry , photochemistry , singlet oxygen , quantum yield , photodissociation , radical , spin trapping , adduct , singlet state , oxygen , nitrosobenzene , excited state , catalysis , organic chemistry , fluorescence , physics , quantum mechanics , nuclear physics
Photolysis of gilvocarcin (GV) at 405 nm in argon saturated dimethylsulfoxide (DMSO) or 50% DMSO‐water solutions in the presence of the sodium salt of 3,5‐dibromo‐2,6‐dideutero‐4‐nitrosobenzene sulfonic acid (DBNBS‐d 2 ) generates the CH 3 ‐DBNBS‐d 2 spin adduct. It is postulated that this spin adduct is produced by photoreduction of DMSO by GV and the consequent formation and trapping of the generated methyl radicals. Gilvocarcin V also photoreduces oxygen and methyl viologen with quantum yields of 0.019 and 0.0012 respectively. The quantum yield for singlet oxygen formation by GV in DMSO, determined by measuring the rate of production of the nitroxyl radical produced by the reaction of 2,2,6,6‐tetramethylpiperidinol with singlet oxygen, was found to be 0.15. Thus, GV photochemistry proceeds by both Type I and Type II pathways which could contribute to the reported GV phototoxicity in biological systems.