Excited-State Photophysics of Hypericin and Its Hexamethoxy Analog: Intramolecular Proton Transfer as a Nonradiative Process in Hypericin
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منابع مشابه
Excited-State Intramolecular H Atom Transfer of Hypericin and Hypocrellin A Investigated by Fluorescence Upconversion
The excited-state intramolecular H atom transfer reaction occurring in hypericin and hypocrellin A is investigated by means of the fluorescence upconversion technique in a variety of solvents. Rising components of ∼10 ps, attributable to intramolecular H atom transfer, are clearly observed in the fluorescence upconversion traces of both hypericin and hypocrellin A. The amplitude of the rising c...
متن کاملRoles of oxygen and photoinduced acidification in the light-dependent antiviral activity of hypocrellin A.
Hypocrellin A displays photoinduced antiviral activity, in particular against the human immunodeficiency virus (HIV), as does its counterpart, hypericin. Although hypocrellin A, like hypericin, executes an excited-state intramolecular proton transfer, it differs from hypericin in two important ways. Unlike hypericin, hypocrellin A absolutely requires oxygen for its antiviral activity. Also, whe...
متن کاملExcited state intramolecular proton transfer (ESIPT) in dihydroxyphenyl anthracenes.
The photochemistry of three 9-(dihydroxyphenyl)anthracenes 6-8 was studied in neat CH(3)CN and selected organic solvents, to investigate excited state intramolecular proton transfer (ESIPT) from the phenol to the anthracene moiety. In D(2)O-CH(3)CN mixtures, the observed deuterium exchange of 6-8 is consistent with water-mediated (formal) ESIPT process from the ortho phenolic OH to the 10'-posi...
متن کاملSolvent Dependence on the Intramolecular Excited-State Proton or Hydrogen Atom Transfer in Hypocrellin
Hypocrellin and its analog, hypericin (Figure 1), are naturally occurring quinones that have been used for centuries as folk medicines in the orient and the occident and that have attracted much interest because of their light-induced toxicity toward the human immunodeficiency virus (HIV).1The structural similarities of hypocrellin and hypericin would seem to suggest that hypocrellin exhibits e...
متن کاملExcited-state intramolecular proton transfer as a fluorescence probe for protein binding-site static polarity.
A fluorescence probe is introduced for protein conformation and binding-site monitoring as the proton-transfer (PT) tautomer fluorescence by using 4-hydroxy-5-azaphenanthrene (HAP) as a prototype. A typical grossly-wavelength-shifted PT fluorescence for HAP is observed in the 600-nm spectral region for this UV-absorbing molecule (absorption onset, 400 nm), for which case PT occurs even in proti...
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ژورنال
عنوان ژورنال: Journal of the American Chemical Society
سال: 1997
ISSN: 0002-7863,1520-5126
DOI: 10.1021/ja962476h