UV-Dissipation Mechanisms in the Eumelanin Building Block DHICA.
(2010) In ChemPhysChem 11(11). p.2424-2431- Abstract
- The UV-dissipative mechanisms of the eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and the 4,7-dideutero derivative (DHICA-d(2)) in buffered H(2)O or D(2)O have been characterized by using ultrafast time-resolved fluorescence spectroscopy. Excitation of the carboxylate anion form, the dominating state at neutral pH, leads to dual fluorescence. The band peaking at lambda=378 nm is caused by emission from the excited initial geometry. The second band around lambda=450 nm is owed to a complex formed between the mono-anion and specific buffer components. In the absence of complex formation, the mono-anion solely decays non-radiatively or by emission with a lifetime of about 2.1 ns. Excitation of the neutral carboxylic... (More)
- The UV-dissipative mechanisms of the eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and the 4,7-dideutero derivative (DHICA-d(2)) in buffered H(2)O or D(2)O have been characterized by using ultrafast time-resolved fluorescence spectroscopy. Excitation of the carboxylate anion form, the dominating state at neutral pH, leads to dual fluorescence. The band peaking at lambda=378 nm is caused by emission from the excited initial geometry. The second band around lambda=450 nm is owed to a complex formed between the mono-anion and specific buffer components. In the absence of complex formation, the mono-anion solely decays non-radiatively or by emission with a lifetime of about 2.1 ns. Excitation of the neutral carboxylic acid state, which dominates at acidic pH, leads to a weak emission around lambda=427 nm with a short lifetime of 240 ps. This emission originates from the zwitterionic state, formed upon excitation of the neutral state by sub-ps excited-state intramolecular proton transfer (ESIPT) between the carboxylic acid group and the indole nitrogen. Future studies will unravel whether this also occurs in larger building blocks and ESIPT is a built-in photoprotective mechanism in epidermal eumelanin. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1625770
- author
- Huijser, Annemarie LU ; Pezzella, Alessandro ; Hannestad, Jonas K ; Panzella, Lucia ; Napolitano, Alessandra ; d'Ischia, Marco and Sundström, Villy LU
- organization
- publishing date
- 2010
- type
- Contribution to journal
- publication status
- published
- subject
- in
- ChemPhysChem
- volume
- 11
- issue
- 11
- pages
- 2424 - 2431
- publisher
- John Wiley & Sons Inc.
- external identifiers
-
- wos:000281061500021
- pmid:20572257
- scopus:84925287392
- pmid:20572257
- ISSN
- 1439-7641
- DOI
- 10.1002/cphc.201000257
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Chemical Physics (S) (011001060)
- id
- 434b512b-14a6-44ad-b0c7-ab24d395fbae (old id 1625770)
- date added to LUP
- 2016-04-01 10:49:21
- date last changed
- 2022-01-26 02:49:39
@article{434b512b-14a6-44ad-b0c7-ab24d395fbae,
abstract = {{The UV-dissipative mechanisms of the eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and the 4,7-dideutero derivative (DHICA-d(2)) in buffered H(2)O or D(2)O have been characterized by using ultrafast time-resolved fluorescence spectroscopy. Excitation of the carboxylate anion form, the dominating state at neutral pH, leads to dual fluorescence. The band peaking at lambda=378 nm is caused by emission from the excited initial geometry. The second band around lambda=450 nm is owed to a complex formed between the mono-anion and specific buffer components. In the absence of complex formation, the mono-anion solely decays non-radiatively or by emission with a lifetime of about 2.1 ns. Excitation of the neutral carboxylic acid state, which dominates at acidic pH, leads to a weak emission around lambda=427 nm with a short lifetime of 240 ps. This emission originates from the zwitterionic state, formed upon excitation of the neutral state by sub-ps excited-state intramolecular proton transfer (ESIPT) between the carboxylic acid group and the indole nitrogen. Future studies will unravel whether this also occurs in larger building blocks and ESIPT is a built-in photoprotective mechanism in epidermal eumelanin.}},
author = {{Huijser, Annemarie and Pezzella, Alessandro and Hannestad, Jonas K and Panzella, Lucia and Napolitano, Alessandra and d'Ischia, Marco and Sundström, Villy}},
issn = {{1439-7641}},
language = {{eng}},
number = {{11}},
pages = {{2424--2431}},
publisher = {{John Wiley & Sons Inc.}},
series = {{ChemPhysChem}},
title = {{UV-Dissipation Mechanisms in the Eumelanin Building Block DHICA.}},
url = {{http://dx.doi.org/10.1002/cphc.201000257}},
doi = {{10.1002/cphc.201000257}},
volume = {{11}},
year = {{2010}},
}