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Article
Excited-State Intramolecular H Atom Transfer of Hypericin and Hypocrellin A Investigated by Fluorescence Upconversion
The Journal of Physical Chemistry A
  • Andrei V. Smirnov, Ames Laboratory
  • K. Das, Iowa State University
  • D. S. English, Iowa State University
  • Z. Wan, Iowa State University
  • George A. Kraus, Iowa State University
  • Jacob W. Petrich, Iowa State University
Document Type
Article
Publication Version
Published Version
Publication Date
9-16-1999
DOI
10.1021/jp992436a
Abstract
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 component is emission wavelength dependent and occurs on the blue edge of the emission spectra. Neither in hypericin nor in hypocrellin A does this fluorescent component exhibit a deuterium isotope effect. This result identifies it with the ∼10 ps component, also lacking a deuterium isotope effect, observed in hypericin in transient absorption measurements monitoring stimulated emission. The clear and complementary observation in fluorescence of the ∼10 ps component in both hypericin and hypocrellin A is a crucial link in refining a unified model of the hypericin and hypocrellin photophysics that we first proposed in J. Phys. Chem. B 1998, 102, 6098.
Comments

Reprinted (adapted) with permission from The Journal of Physical Chemistry A, 103(40); 7949-7957. doi: 10.1021/jp992436a. Copyright 1999 American Chemical Society.

Copyright Owner
American Chemical Society
Language
en
File Format
application/pdf
Citation Information
Andrei V. Smirnov, K. Das, D. S. English, Z. Wan, et al.. "Excited-State Intramolecular H Atom Transfer of Hypericin and Hypocrellin A Investigated by Fluorescence Upconversion" The Journal of Physical Chemistry A Vol. 103 Iss. 40 (1999) p. 7949 - 7957
Available at: http://works.bepress.com/george_kraus/55/