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

34 Citations (Scopus)


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
Issue number9
Publication statusPublished - 2013


  • METIS-295650
  • IR-85481


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