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Title: Artificial Photosynthetic Reaction Center Exhibiting Acid-Responsive Regulation of Photoinduced Charge Separation

Abstract

Charge separation (CS) is the primary light-driven reaction in photosynthesis whereas onphotochemical quenching (NPQ) is a photoprotective regulatory mechanism employed by many photosynthetic organisms to dynamically modulate energy flow within the photosynthetic apparatus in response to fluctuating light conditions. Activated by decreases in lumen pH produced during periods of high photon flux, NPQ induces rapid thermal dissipation of excess excitation energy. As a result, the rate of CS decreases, thereby limiting the accumulation of potentially deleterious reactive intermediates and byproducts. In this article, a molecular triad that functionally mimics the effects of NPQ associated with an artificial photosynthetic reaction center is described. Steady-state absorption and emission, time-resolved fluorescence, and transient absorption spectroscopies have been used to demonstrate a 1 order of magnitude reduction in the CS quantum yield via reversible protonation of an excited-state-quenching molecular switch moiety. As in the natural system, the populations of unquenched and quenched states and therefore the overall yields of CS were found to be dependent on acid concentration.

Authors:
 [1];  [1];  [2];  [1];  [1];  [1]
  1. Arizona State Univ., Tempe, AZ (United States). School of Molecular Sciences
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Biophysics and Integrated Bioimaging Division; Univ. of California, Berkeley, CA (United States). Dept. of Chemistry and QB3 Inst.
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1378341
DOE Contract Number:
AC03-76F000098; AC02-05CH11231; FG02-03ER15393
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry; Journal Volume: 120; Journal Issue: 40
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Pahk, Ian, Kodis, Gerdenis, Fleming, Graham R., Moore, Thomas A., Moore, Ana L., and Gust, Devens. Artificial Photosynthetic Reaction Center Exhibiting Acid-Responsive Regulation of Photoinduced Charge Separation. United States: N. p., 2016. Web. doi:10.1021/acs.jpcb.6b07609.
Pahk, Ian, Kodis, Gerdenis, Fleming, Graham R., Moore, Thomas A., Moore, Ana L., & Gust, Devens. Artificial Photosynthetic Reaction Center Exhibiting Acid-Responsive Regulation of Photoinduced Charge Separation. United States. doi:10.1021/acs.jpcb.6b07609.
Pahk, Ian, Kodis, Gerdenis, Fleming, Graham R., Moore, Thomas A., Moore, Ana L., and Gust, Devens. Fri . "Artificial Photosynthetic Reaction Center Exhibiting Acid-Responsive Regulation of Photoinduced Charge Separation". United States. doi:10.1021/acs.jpcb.6b07609.
@article{osti_1378341,
title = {Artificial Photosynthetic Reaction Center Exhibiting Acid-Responsive Regulation of Photoinduced Charge Separation},
author = {Pahk, Ian and Kodis, Gerdenis and Fleming, Graham R. and Moore, Thomas A. and Moore, Ana L. and Gust, Devens},
abstractNote = {Charge separation (CS) is the primary light-driven reaction in photosynthesis whereas onphotochemical quenching (NPQ) is a photoprotective regulatory mechanism employed by many photosynthetic organisms to dynamically modulate energy flow within the photosynthetic apparatus in response to fluctuating light conditions. Activated by decreases in lumen pH produced during periods of high photon flux, NPQ induces rapid thermal dissipation of excess excitation energy. As a result, the rate of CS decreases, thereby limiting the accumulation of potentially deleterious reactive intermediates and byproducts. In this article, a molecular triad that functionally mimics the effects of NPQ associated with an artificial photosynthetic reaction center is described. Steady-state absorption and emission, time-resolved fluorescence, and transient absorption spectroscopies have been used to demonstrate a 1 order of magnitude reduction in the CS quantum yield via reversible protonation of an excited-state-quenching molecular switch moiety. As in the natural system, the populations of unquenched and quenched states and therefore the overall yields of CS were found to be dependent on acid concentration.},
doi = {10.1021/acs.jpcb.6b07609},
journal = {Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry},
number = 40,
volume = 120,
place = {United States},
year = {Fri Sep 16 00:00:00 EDT 2016},
month = {Fri Sep 16 00:00:00 EDT 2016}
}