Photosensitized generation of singlet molecular oxygen by aryloxazinones

摘要: Abstract The photophysical properties, the capacity to produce singlet molecular oxygen by sensitization and photostability of a series 20 aryloxazinones one quinoxalinone have been evaluated using combination methods including steady-state time-resolved spectroscopic techniques. photophysics aryloxazinone derivatives consequently its is very dependent on structure. Benzoxazinone substituted in para position 2-phenyl group ( 1 )–( 3 ) low fluorescence quantum yields moderate yields. Inclusion electron donors groups 7 aromatic fused moiety heterocyclic ring 4 6 ), increases significantly emission from excited state with concomitant diminution ability oxygen. An exception corresponds 7-methoxy-2-phenylbenzoxazinone able generate larger quantities photodecompose less than 2% under large energy doses aerobic irradiation conditions. In general, 2-methyl naphthoxazinones 17 are more fluorescent compounds corresponding benzo series, Exceptions 13 9-methoxy-2-methyl 14 that efficiently, however, appreciable decomposition. most promising be employed as sensitizers anthracene like 3-phenyl-2H-naphtho[2,3-b][1,4]-oxazin-2-one 19 1-methyl-3-phenylquinoxalin-2(1H)-one 21 ). These photostable absence presence donor additives irradiation, accomplishing all requisites good sensitizer high yields, almost independently solvent polarity.