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Title: Morphological Control of Chromophore Spin State in Zinc Porphyrin–Peptide Assemblies

Abstract

Self-assembled peptide micelles and fibers demonstrate unique control over the photophysical properties of the bound, light-activated chromophore, zinc protoporphyrin IX, (PPIX)Zn. Micelles encapsulate either a mixture of uncoordinated and coordinated (PPIX)Zn or all coordinated depending on the ratio of peptide/porphyrin. As the ratio increases toward a 1:1 micelle/porphyrin ratio, providing the chromophore with a discrete coordination environment reminiscent of unstructured proteins, the micelles favor triplet formation. Fibers, however, promote a linear array of porphyrin molecules that dictates exciton hopping and excimer formation at ratios as high as 60:1, peptide/porphyrin. However, even in fibers, the formation of the triplet species increases with increasing peptide/porphyrin ratio due to increased spatial separation between neighboring chromophores facilitating intersystem crossing. Full characterization of the micelles structures and comparison to the fibers lead to the comparison with natural systems and the ability to control the excited populations that have utility in photocatalytic processes. In addition, the incorporation of a second chromophore, heme, yields an electron transfer pathway in both micelles and fibers that highlights the utility of the peptide assemblies when engineering multichromophore arrays as inspired by natural, photosynthetic proteins.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1607373
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 142; Journal Issue: 1; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Fry, H. Christopher, Solomon, Lee A., Diroll, Benjamin T., Liu, Yuzi, Gosztola, David J., and Cohn, Hannah M. Morphological Control of Chromophore Spin State in Zinc Porphyrin–Peptide Assemblies. United States: N. p., 2019. Web. doi:10.1021/jacs.9b09935.
Fry, H. Christopher, Solomon, Lee A., Diroll, Benjamin T., Liu, Yuzi, Gosztola, David J., & Cohn, Hannah M. Morphological Control of Chromophore Spin State in Zinc Porphyrin–Peptide Assemblies. United States. https://doi.org/10.1021/jacs.9b09935
Fry, H. Christopher, Solomon, Lee A., Diroll, Benjamin T., Liu, Yuzi, Gosztola, David J., and Cohn, Hannah M. Mon . "Morphological Control of Chromophore Spin State in Zinc Porphyrin–Peptide Assemblies". United States. https://doi.org/10.1021/jacs.9b09935. https://www.osti.gov/servlets/purl/1607373.
@article{osti_1607373,
title = {Morphological Control of Chromophore Spin State in Zinc Porphyrin–Peptide Assemblies},
author = {Fry, H. Christopher and Solomon, Lee A. and Diroll, Benjamin T. and Liu, Yuzi and Gosztola, David J. and Cohn, Hannah M.},
abstractNote = {Self-assembled peptide micelles and fibers demonstrate unique control over the photophysical properties of the bound, light-activated chromophore, zinc protoporphyrin IX, (PPIX)Zn. Micelles encapsulate either a mixture of uncoordinated and coordinated (PPIX)Zn or all coordinated depending on the ratio of peptide/porphyrin. As the ratio increases toward a 1:1 micelle/porphyrin ratio, providing the chromophore with a discrete coordination environment reminiscent of unstructured proteins, the micelles favor triplet formation. Fibers, however, promote a linear array of porphyrin molecules that dictates exciton hopping and excimer formation at ratios as high as 60:1, peptide/porphyrin. However, even in fibers, the formation of the triplet species increases with increasing peptide/porphyrin ratio due to increased spatial separation between neighboring chromophores facilitating intersystem crossing. Full characterization of the micelles structures and comparison to the fibers lead to the comparison with natural systems and the ability to control the excited populations that have utility in photocatalytic processes. In addition, the incorporation of a second chromophore, heme, yields an electron transfer pathway in both micelles and fibers that highlights the utility of the peptide assemblies when engineering multichromophore arrays as inspired by natural, photosynthetic proteins.},
doi = {10.1021/jacs.9b09935},
journal = {Journal of the American Chemical Society},
number = 1,
volume = 142,
place = {United States},
year = {Mon Dec 09 00:00:00 EST 2019},
month = {Mon Dec 09 00:00:00 EST 2019}
}

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