Abstract：
:We investigated the effect of the cation-π interaction on the susceptibility of a tryptophan model system toward interaction with singlet oxygen, that is, type II photooxidation. The model system consists of two indole units linked to a lariat crown ether to measure the total rate of removal of singlet oxygen by the indole units in the presence of sodium cations (i.e. indole units subject to a cation-π interaction) and in the absence of this interaction. We found that the cation-π interaction significantly decreases the total rate of removal of singlet oxygen (kT ) for the model system, that is, (kT = 2.4 ± 0.2) × 108 m-1 s-1 without sodium cation vs (kT = 6.9 ± 0.9) × 107 m-1 s-1 upon complexation of sodium cation to the crown ether. Furthermore, we found that the indole moieties undergo type I photooxidation processes with triplet excited methylene blue; this effect is also inhibited by the cation-π interaction. The chemical rate of reaction of the indole groups with singlet oxygen is also slower upon complexation of sodium cation in our model system, although we were unable to obtain an exact ratio due to differences of the chemical reaction rates of the two indole moieties.
journal_name
Photochem Photobioljournal_title
Photochemistry and photobiologyauthors
Arevalo GE,Cagan DA,Monsour CG,Garcia AC,McCurdy A,Selke Mdoi
10.1111/php.13287subject
Has Abstractpub_date
2020-11-01 00:00:00pages
1200-1207issue
6eissn
0031-8655issn
1751-1097journal_volume
96pub_type
杂志文章abstract：:The phototoxic anti-hyperlipoproteinemic drug fenofibrate was found to be photolabile under aerobic and anaerobic conditions. Irradiation under argon of a methanol solution of this drug produced the photoproducts isopropyl 4-(1-[4-chlorophenyl]-1,2-dihydroxy)ethylphenoxyisobutyrate, 1,2-bis(4-chlorophenyl)-1,2bis (4-[...
journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
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更新日期：2017-07-01 00:00:00
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journal_title：Photochemistry and photobiology
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journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：
更新日期：1999-04-01 00:00:00
abstract：:Abstract- Time-resolved transmittance was used to extract in vivo optical properties of leaves of green plants experimentally. In time-resolved transmittance measurements an ultrashort light pulse is directed onto the surface of the object and the transmitted light is measured with a time resolution in the range of pi...
journal_title：Photochemistry and photobiology
pub_type： 杂志文章
doi：10.1111/j.1751-1097.1999.tb03281.x
更新日期：1999-02-01 00:00:00
