skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

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

Authors:
; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1326239
Grant/Contract Number:
SC0001011
Resource Type:
Journal Article: 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; Related Information: CHORUS Timestamp: 2017-06-24 19:31:22; Journal ID: ISSN 0027-8424
Publisher:
Proceedings of the National Academy of Sciences
Country of Publication:
United States
Language:
English

Citation Formats

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., 2016. 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 = {},
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
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1073/pnas.1611496113

Citation Metrics:
Cited by: 1work
Citation information provided by
Web of Science

Save / Share:
  • The hexagonal perovskites Ba3BiIr2O9, Ba3BiRu2O9 and Ba4BiIr3O12 all undergo pressure-induced 1% volume collapses above 5 GPa. These first-order transitions have been ascribed to internal transfer of valence electrons between bismuth and iridium/ruthenium, which is driven by external applied pressure because the reduction in volume achieved by emptying the 6s shell of bismuth upon oxidation to Bi5+ is greater in magnitude than the increase in volume by reducing iridium or ruthenium. Here, we report direct observation of these valence transfers for the first time, using high-pressure X-ray absorption near-edge spectroscopy (XANES) measurements. Our data also support the highly unusual “4+” nominalmore » oxidation state of bismuth in these compounds, although the possibility of local disproportionation into Bi3+/Bi5+ cannot be definitively ruled out. Ab initio calculations reproduce the transition, support its interpretation as a valence electron transfer from Bi to Ir/Ru, and suggest that the high-pressure phase may show metallic behavior (in contrast to the insulating ambient-pressure phase).« less
  • Dramatic rate enhancements are observed for the oxidation of phenols, including tyrosine, at indium-tin oxide electrodes modified by the addition of the electron-transfer relays [M II(bpy) 2(4,4'-(HO) 2P(O)CH 2) 2bpy)] 2+ (M = Ru, Os) with clear evidence for the importance of proton-coupled electron transfer and concerted electron-proton transfer.
  • The simultaneous, concerted transfer of electrons and protons—electron-proton transfer (EPT)—is an important mechanism utilized in chemistry and biology to avoid high energy intermediates. There are many examples of thermally activated EPT in ground-state reactions and in excited states following photoexcitation and thermal relaxation. Here we report application of ultrafast excitation with absorption and Raman monitoring to detect a photochemically driven EPT process (photo-EPT). In this process, both electrons and protons are transferred during the absorption of a photon. Photo-EPT is induced by intramolecular charge-transfer (ICT) excitation of hydrogen-bonded-base adducts with either a coumarin dye or 4-nitro-4'-biphenylphenol. Femtosecond transient absorption spectralmore » measurements following ICT excitation reveal the appearance of two spectroscopically distinct states having different dynamical signatures. One of these states corresponds to a conventional ICT excited state in which the transferring H⁺ is initially associated with the proton donor. Proton transfer to the base (B) then occurs on the picosecond time scale. The other state is an ICT-EPT photoproduct. Upon excitation it forms initially in the nuclear configuration of the ground state by application of the Franck–Condon principle. However, due to the change in electronic configuration induced by the transition, excitation is accompanied by proton transfer with the protonated base formed with a highly elongated ⁺H–B bond. Coherent Raman spectroscopy confirms the presence of a vibrational mode corresponding to the protonated base in the optically prepared state.« less