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Title: Direct observation of light-driven, concerted electron–proton transfer

Here, the phenols 4-methylphenol, 4-methoxyphenol, and N-acetyl-tyrosine form hydrogen-bonded adducts with N-methyl-4, 4'-bipyridinium cation (MQ +) in aqueous solution as evidenced by the appearance of low-energy, low-absorptivity features in UV-visible spectra. They are assigned to the known examples of optically induced, concerted electron–proton transfer, photoEPT. The results of ultrafast transient absorption measurements on the assembly MeOPhO-H---MQ + are consistent with concerted EPT by the instantaneous appearance of spectral features for MeOPhO·---H-MQ + in the transient spectra at the first observation time of 0.1 ps. The transient decays to MeOPhO-H---MQ + in 2.5 ps, accompanied by the appearance of oscillations in the decay traces with a period of ~1 ps, consistent with a vibrational coherence and relaxation from a higher υ(N-H) vibrational level or levels on the timescale for back EPT.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3]
  1. Univ. of North Carolina at Chapel Hill, Chapel Hill, NC (United States)
  2. Shanxi Univ., Shanxi (China)
  3. Memorial Univ. of Newfoundland, St. John's, NL (Canada)
Publication Date:
Grant/Contract Number:
SC0001011
Type:
Published Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America
Additional Journal Information:
Journal Volume: 113; Journal Issue: 40; Journal ID: ISSN 0027-8424
Publisher:
National Academy of Sciences, Washington, DC (United States)
Research Org:
Univ. of North Carolina at Chapel Hill, Chapel Hill, NC (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; light driven; electron; proton; transfer; photoEPT
OSTI Identifier:
1326239
Alternate Identifier(s):
OSTI ID: 1464947

Gagliardi, Christopher J., Wang, Li, Dongare, Prateek, Brennaman, M. Kyle, Papanikolas, John M., Meyer, Thomas J., and Thompson, David W.. Direct observation of light-driven, concerted electron–proton transfer. United States: N. p., Web. doi:10.1073/pnas.1611496113.
Gagliardi, Christopher J., Wang, Li, Dongare, Prateek, Brennaman, M. Kyle, Papanikolas, John M., Meyer, Thomas J., & Thompson, David W.. Direct observation of light-driven, concerted electron–proton transfer. United States. doi:10.1073/pnas.1611496113.
Gagliardi, Christopher J., Wang, Li, Dongare, Prateek, Brennaman, M. Kyle, Papanikolas, John M., Meyer, Thomas J., and Thompson, David W.. 2016. "Direct observation of light-driven, concerted electron–proton transfer". United States. doi:10.1073/pnas.1611496113.
@article{osti_1326239,
title = {Direct observation of light-driven, concerted electron–proton transfer},
author = {Gagliardi, Christopher J. and Wang, Li and Dongare, Prateek and Brennaman, M. Kyle and Papanikolas, John M. and Meyer, Thomas J. and Thompson, David W.},
abstractNote = {Here, the phenols 4-methylphenol, 4-methoxyphenol, and N-acetyl-tyrosine form hydrogen-bonded adducts with N-methyl-4, 4'-bipyridinium cation (MQ+) in aqueous solution as evidenced by the appearance of low-energy, low-absorptivity features in UV-visible spectra. They are assigned to the known examples of optically induced, concerted electron–proton transfer, photoEPT. The results of ultrafast transient absorption measurements on the assembly MeOPhO-H---MQ+ are consistent with concerted EPT by the instantaneous appearance of spectral features for MeOPhO·---H-MQ+ in the transient spectra at the first observation time of 0.1 ps. The transient decays to MeOPhO-H---MQ+ in 2.5 ps, accompanied by the appearance of oscillations in the decay traces with a period of ~1 ps, consistent with a vibrational coherence and relaxation from a higher υ(N-H) vibrational level or levels on the timescale for back EPT.},
doi = {10.1073/pnas.1611496113},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = 40,
volume = 113,
place = {United States},
year = {2016},
month = {9}
}