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

A. Corani, A. Pezzella, T. Passcher, T. Gustavsson, D. Markovitsi, Jannetje Maria Huijser, M. D'Ischia, V. Sundström

Research output: Contribution to journalArticleAcademicpeer-review

27 Citations (Scopus)

Abstract

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 × 108 s
Original languageEnglish
Pages (from-to)1383-1388
Number of pages6
JournalJournal of physical chemistry letters
Volume4
Issue number9
DOIs
Publication statusPublished - 2013

Keywords

  • METIS-295650
  • IR-85481

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    Corani, A., Pezzella, A., Passcher, T., Gustavsson, T., Markovitsi, D., Huijser, J. M., ... Sundström, V. (2013). Excited-State Proton-Transfer Processes of DHICA Resolved: From Sub-Picoseconds to Nanoseconds. Journal of physical chemistry letters, 4(9), 1383-1388. https://doi.org/10.1021/jz400437q