Role of Solvent, pH, and Molecular Size in Excited-State Deactivation of Key Eumelanin Building Blocks: Implications for Melanin Pigment Photostability.

Magdalena Gauden; A Pezzella; L Panzella; M Neves-Petersen; E Skovsen; S Petersen; K Mullen; A Napolitano; M d'Ischia; Villy Sundström

doi:10.1021/ja806345q

Role of Solvent, pH, and Molecular Size in Excited-State Deactivation of Key Eumelanin Building Blocks: Implications for Melanin Pigment Photostability.

Magdalena Gauden, A Pezzella, L Panzella, M Neves-Petersen, E Skovsen, S Petersen, K Mullen, A Napolitano, M d'Ischia, Villy Sundström

Chemical Physics

Research output: Contribution to journal › Article › peer-review

Abstract

Ultrafast time-resolved fluorescence spectroscopy has been used to investigate the excited-state dynamics of the basic eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA), its acetylated, methylated, and carboxylic ester derivatives, and two oligomers, a dimer and a trimer in the O-acetylated forms. The results show that (1) excited-state decays are faster for the trimer relative to the monomer; (2) for parent DHICA, excited-state lifetimes are much shorter in aqueous acidic medium (380 ps) as compared to organic solvent (acetonitrile, 2.6 ns); and (3) variation of fluorescence spectra and excited-state dynamics can be understood as a result of excited-state intramolecular proton transfer (ESIPT). The dependence on the DHICA oligomer size of the excited-state deactivation and its ESIPT mechanism provides important insight into the photostability and the photoprotective function of eumelanin. Mechanistic analogies with the corresponding processes in DNA and other biomolecules are recognized.

Original language	English
Pages (from-to)	17038-17043
Journal	Journal of the American Chemical Society
Volume	130
Issue number	50
DOIs	https://doi.org/10.1021/ja806345q
Publication status	Published - 2008

Bibliographical note

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)

Subject classification (UKÄ)

Atom and Molecular Physics and Optics

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10.1021/ja806345q

Cite this

Gauden, M., Pezzella, A., Panzella, L., Neves-Petersen, M., Skovsen, E., Petersen, S., Mullen, K., Napolitano, A., d'Ischia, M., & Sundström, V. (2008). Role of Solvent, pH, and Molecular Size in Excited-State Deactivation of Key Eumelanin Building Blocks: Implications for Melanin Pigment Photostability. Journal of the American Chemical Society, 130(50), 17038-17043. https://doi.org/10.1021/ja806345q

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title = "Role of Solvent, pH, and Molecular Size in Excited-State Deactivation of Key Eumelanin Building Blocks: Implications for Melanin Pigment Photostability.",

abstract = "Ultrafast time-resolved fluorescence spectroscopy has been used to investigate the excited-state dynamics of the basic eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA), its acetylated, methylated, and carboxylic ester derivatives, and two oligomers, a dimer and a trimer in the O-acetylated forms. The results show that (1) excited-state decays are faster for the trimer relative to the monomer; (2) for parent DHICA, excited-state lifetimes are much shorter in aqueous acidic medium (380 ps) as compared to organic solvent (acetonitrile, 2.6 ns); and (3) variation of fluorescence spectra and excited-state dynamics can be understood as a result of excited-state intramolecular proton transfer (ESIPT). The dependence on the DHICA oligomer size of the excited-state deactivation and its ESIPT mechanism provides important insight into the photostability and the photoprotective function of eumelanin. Mechanistic analogies with the corresponding processes in DNA and other biomolecules are recognized.",

author = "Magdalena Gauden and A Pezzella and L Panzella and M Neves-Petersen and E Skovsen and S Petersen and K Mullen and A Napolitano and M d'Ischia and Villy Sundstr{\"o}m",

note = "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)",

year = "2008",

doi = "10.1021/ja806345q",

language = "English",

volume = "130",

pages = "17038--17043",

journal = "Journal of the American Chemical Society",

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Gauden, M, Pezzella, A, Panzella, L, Neves-Petersen, M, Skovsen, E, Petersen, S, Mullen, K, Napolitano, A, d'Ischia, M & Sundström, V 2008, 'Role of Solvent, pH, and Molecular Size in Excited-State Deactivation of Key Eumelanin Building Blocks: Implications for Melanin Pigment Photostability.', Journal of the American Chemical Society, vol. 130, no. 50, pp. 17038-17043. https://doi.org/10.1021/ja806345q

TY - JOUR

T1 - Role of Solvent, pH, and Molecular Size in Excited-State Deactivation of Key Eumelanin Building Blocks: Implications for Melanin Pigment Photostability.

AU - Gauden, Magdalena

AU - Pezzella, A

AU - Panzella, L

AU - Neves-Petersen, M

AU - Skovsen, E

AU - Petersen, S

AU - Mullen, K

AU - Napolitano, A

AU - d'Ischia, M

AU - Sundström, Villy

N1 - 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)

PY - 2008

Y1 - 2008

N2 - Ultrafast time-resolved fluorescence spectroscopy has been used to investigate the excited-state dynamics of the basic eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA), its acetylated, methylated, and carboxylic ester derivatives, and two oligomers, a dimer and a trimer in the O-acetylated forms. The results show that (1) excited-state decays are faster for the trimer relative to the monomer; (2) for parent DHICA, excited-state lifetimes are much shorter in aqueous acidic medium (380 ps) as compared to organic solvent (acetonitrile, 2.6 ns); and (3) variation of fluorescence spectra and excited-state dynamics can be understood as a result of excited-state intramolecular proton transfer (ESIPT). The dependence on the DHICA oligomer size of the excited-state deactivation and its ESIPT mechanism provides important insight into the photostability and the photoprotective function of eumelanin. Mechanistic analogies with the corresponding processes in DNA and other biomolecules are recognized.

AB - Ultrafast time-resolved fluorescence spectroscopy has been used to investigate the excited-state dynamics of the basic eumelanin building block 5,6-dihydroxyindole-2-carboxylic acid (DHICA), its acetylated, methylated, and carboxylic ester derivatives, and two oligomers, a dimer and a trimer in the O-acetylated forms. The results show that (1) excited-state decays are faster for the trimer relative to the monomer; (2) for parent DHICA, excited-state lifetimes are much shorter in aqueous acidic medium (380 ps) as compared to organic solvent (acetonitrile, 2.6 ns); and (3) variation of fluorescence spectra and excited-state dynamics can be understood as a result of excited-state intramolecular proton transfer (ESIPT). The dependence on the DHICA oligomer size of the excited-state deactivation and its ESIPT mechanism provides important insight into the photostability and the photoprotective function of eumelanin. Mechanistic analogies with the corresponding processes in DNA and other biomolecules are recognized.

U2 - 10.1021/ja806345q

DO - 10.1021/ja806345q

M3 - Article

SN - 1520-5126

VL - 130

SP - 17038

EP - 17043

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 50

ER -

Role of Solvent, pH, and Molecular Size in Excited-State Deactivation of Key Eumelanin Building Blocks: Implications for Melanin Pigment Photostability.

Abstract

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