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EXCITED STATE PROPERTIES OF ∝aL‐TERTHIENYL and RELATED MOLECULES
Author(s) -
Reyftmann J. P.,
Kagan J.,
Santus R.,
Morliere P.
Publication year - 1985
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.1751-1097.1985.tb03439.x
Subject(s) - photochemistry , thiophene , quantum yield , triplet state , chemistry , cyclohexane , singlet oxygen , fluorescence , flash photolysis , excited state , indole test , molecule , porphyrin , oxygen , organic chemistry , reaction rate constant , kinetics , physics , quantum mechanics , nuclear physics
— The photophysical and photochemical properties of thiophene derivatives have been studied by fluorescence and by 353 nm laser flash spectroscopy. α‐Terthienyl and its derivatives show a moderate fluorescence quantum yield (less than 0.1) in cyclohexane, ethanol, or TritonX–100 micelles. An additional thiophene ring increases this value to 0.2 in ethanol or micelles. The transient triplet state of the six thiophenes is characterized by strong absorptions (ε⋍ 50000 M ‐1 cm ‐1 ) in the visible region. These triplet states are very long lived. They react with oxygen, producing singlet oxygen very efficiently because of their high quantum yield of triplet formation (0.1 to 0.3). They do not react with excellent hydrogen or electron donors such as indole, N‐acetyl tryptophanamide or cysteine. The hydrophobic thiophenes investigated are, therefore, Type II photodynamic agents almost exclusively.