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Villy Sundström in the snow by the sea.

Villy Sundström

Professor emeritus

Villy Sundström in the snow by the sea.

Excited-State Proton-Transfer Processes of DHICA Resolved: From Sub-Picoseconds to Nanoseconds

Author

  • Alice Corani
  • Alessandro Pezzella
  • Torbjörn Pascher
  • Thomas Gustavsson
  • Dimitra Markovitsi
  • Annemarie Huijser
  • Marco d'Ischia
  • Villy Sundström

Summary, in English

Excited-state proton transfer has been hypothesized as a mechanism for UV energy dissipation in eumelanin skin pigments. By using time resolved fluorescence spectroscopy, we show that the previously proposed, but unresolved, excited-state intramolecular proton transfer (ESIPT) of the eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA) occurs with a time constant of 300 fs in aqueous solution but completely stops in methanol. The previously disputed excited-state proton transfer involving the 5- or 6-OH groups of the DHICA anion is now found to occur from the 6-OH group to aqueous solvent with a rate constant of 4.0 x 10(8) s(-1).

Department/s

  • Chemical Physics

Publishing year

2013

Language

English

Pages

1383-1388

Publication/Series

The Journal of Physical Chemistry Letters

Volume

4

Issue

9

Document type

Journal article

Publisher

The American Chemical Society (ACS)

Topic

  • Atom and Molecular Physics and Optics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1948-7185