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

被引:40
|
作者
Corani, Alice [1 ]
Pezzella, Alessandro [2 ]
Pascher, Torbjorn [1 ]
Gustavsson, Thomas [3 ]
Markovitsi, Dimitra [3 ]
Huijser, Annemarie [1 ]
d'Ischia, Marco [2 ]
Sundstrom, Villy [1 ]
机构
[1] Lund Univ, Dept Chem Phys, S-22100 Lund, Sweden
[2] Univ Naples Federico II, Dept Chem Sci, I-80126 Naples, Italy
[3] CEA Saclay, CEA DSM IRAMIS SPAM CNRS, Lab Francis Perrin, URA 2453, F-91191 Gif Sur Yvette, France
来源
基金
欧洲研究理事会; 瑞典研究理事会;
关键词
GREEN FLUORESCENT PROTEIN; 5,6-DIHYDROXYINDOLE-2-CARBOXYLIC ACID; INDOLE-2-CARBOXYLIC ACID; SOLVATION DYNAMICS; STRUCTURAL-CHANGES; EUMELANIN; WATER; MECHANISM; SOLVENT; KEY;
D O I
10.1021/jz400437q
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
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).
引用
收藏
页码:1383 / 1388
页数:6
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