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Title: Exciton Delocalization in Indolenine Squaraine Aggregates Templated by DNA Holliday Junction Scaffolds

Abstract

Exciton delocalization plays a prominent role in the photophysics of molecular aggregates, ultimately governing their particular function or application. DNA is a compelling scaffold in which to template molecular aggregates and promote exciton delocalization. As individual dye molecules are the basis of exciton delocalization in molecular aggregates, their judicious selection is important. Motivated by their excellent photostability and spectral properties, here we examine the ability of squaraine dyes to undergo exciton delocalization when aggregated via a DNA Holliday junction (HJ) template. A commercially available indolenine squaraine dye was chosen for the study given its strong structural resemblance to Cy5, a commercially available cyanine dye previously shown to undergo exciton delocalization in DNA HJs. Three types of DNA-dye aggregate configurations—transverse dimer, adjacent dimer, and tetramer—were investigated. Signatures of exciton delocalization were observed in all squaraine-DNA aggregates. Specifically, strong blue shift and Davydov splitting were observed in steady-state absorption spectroscopy and exciton-induced features were evident in circular dichroism spectroscopy. Strongly suppressed fluorescence emission provided additional, indirect evidence for exciton delocalization in the DNA-templated squaraine dye aggregates. To quantitatively evaluate and directly compare the excitonic Coulombic coupling responsible for exciton delocalization, the strength of excitonic hopping interactions between the dyes were obtained bymore » simultaneous fitting the experimental steady-state absorption and CD spectra via a Holstein-like Hamiltonian in which, following the theoretical approach of Kühn, Renger, and May, the dominant vibrational mode is explicitly considered. The excitonic hopping strength within indolenine squaraines was found to be comparable to that of the analogous Cy5 DNA-templated aggregate. The squaraine aggregates adopted primarily an H-type (dyes oriented parallel to each other) spatial arrangement. Extracted geometric details of dye mutual orientation in the aggregates enabled close comparison of aggregate configurations and the elucidation of the influence of dye angular relationship on excitonic hopping interactions in squaraine aggregates. Furthermore, these results encourage the application of squaraine-based aggregates in next generation systems driven by molecular excitons.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Boise State Univ., ID (United States)
  2. SETA BioMedicals, LLC, Urbana, IL (United States)
Publication Date:
Research Org.:
Boise State Univ., ID (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
OSTI Identifier:
1670511
Grant/Contract Number:  
SC0020089
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
The Journal of Physical Chemistry B
Additional Journal Information:
Related Information: SUPPORTING INFORMATIONExciton Delocalization in Indolenine Squaraine Aggregates Templated byDNA Holliday Junction Scaffolds1Olga A. Mass; 1Christopher K. Wilson; 1Simon K. Roy; Matthew S. Barclay; 1Lance K. Patten;2Ewald A. Terpetschnig; *1,3Jeunghoon Lee; *1Ryan D. Pensack; *1,4Bernard Yurke;*1,4William B. Knowlton.1Micron School of Materials Science & Engineering, 3Department of Chemistry andBiochemistry, 4Department of Electrical & Computer Engineering, Boise State University, Boise,Idaho 83725, United States2SETA BioMedicals, LLC, 2014 Silver Court East, Urbana, IL 61801, United States; Journal ID: ISSN 1520--6106
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Exciton delocalization; Indolenine Squaraine dye-DNA aggregates; DNA Holliday junctions; Davydov splitting; H-type packing Scaffolds

Citation Formats

Mass, Olga, Wilson, Christopher, Roy, Simon, Barclay, Matthew, Patten, Lance, Terpetschnig, Ewald, Lee, Jeunghoon, Pensack, Ryan, Yurke, Bernard, and Knowlton, William. Exciton Delocalization in Indolenine Squaraine Aggregates Templated by DNA Holliday Junction Scaffolds. United States: N. p., 2020. Web. doi:10.1021/acs.jpcb.0c06480.
Mass, Olga, Wilson, Christopher, Roy, Simon, Barclay, Matthew, Patten, Lance, Terpetschnig, Ewald, Lee, Jeunghoon, Pensack, Ryan, Yurke, Bernard, & Knowlton, William. Exciton Delocalization in Indolenine Squaraine Aggregates Templated by DNA Holliday Junction Scaffolds. United States. https://doi.org/10.1021/acs.jpcb.0c06480
Mass, Olga, Wilson, Christopher, Roy, Simon, Barclay, Matthew, Patten, Lance, Terpetschnig, Ewald, Lee, Jeunghoon, Pensack, Ryan, Yurke, Bernard, and Knowlton, William. Thu . "Exciton Delocalization in Indolenine Squaraine Aggregates Templated by DNA Holliday Junction Scaffolds". United States. https://doi.org/10.1021/acs.jpcb.0c06480.
@article{osti_1670511,
title = {Exciton Delocalization in Indolenine Squaraine Aggregates Templated by DNA Holliday Junction Scaffolds},
author = {Mass, Olga and Wilson, Christopher and Roy, Simon and Barclay, Matthew and Patten, Lance and Terpetschnig, Ewald and Lee, Jeunghoon and Pensack, Ryan and Yurke, Bernard and Knowlton, William},
abstractNote = {Exciton delocalization plays a prominent role in the photophysics of molecular aggregates, ultimately governing their particular function or application. DNA is a compelling scaffold in which to template molecular aggregates and promote exciton delocalization. As individual dye molecules are the basis of exciton delocalization in molecular aggregates, their judicious selection is important. Motivated by their excellent photostability and spectral properties, here we examine the ability of squaraine dyes to undergo exciton delocalization when aggregated via a DNA Holliday junction (HJ) template. A commercially available indolenine squaraine dye was chosen for the study given its strong structural resemblance to Cy5, a commercially available cyanine dye previously shown to undergo exciton delocalization in DNA HJs. Three types of DNA-dye aggregate configurations—transverse dimer, adjacent dimer, and tetramer—were investigated. Signatures of exciton delocalization were observed in all squaraine-DNA aggregates. Specifically, strong blue shift and Davydov splitting were observed in steady-state absorption spectroscopy and exciton-induced features were evident in circular dichroism spectroscopy. Strongly suppressed fluorescence emission provided additional, indirect evidence for exciton delocalization in the DNA-templated squaraine dye aggregates. To quantitatively evaluate and directly compare the excitonic Coulombic coupling responsible for exciton delocalization, the strength of excitonic hopping interactions between the dyes were obtained by simultaneous fitting the experimental steady-state absorption and CD spectra via a Holstein-like Hamiltonian in which, following the theoretical approach of Kühn, Renger, and May, the dominant vibrational mode is explicitly considered. The excitonic hopping strength within indolenine squaraines was found to be comparable to that of the analogous Cy5 DNA-templated aggregate. The squaraine aggregates adopted primarily an H-type (dyes oriented parallel to each other) spatial arrangement. Extracted geometric details of dye mutual orientation in the aggregates enabled close comparison of aggregate configurations and the elucidation of the influence of dye angular relationship on excitonic hopping interactions in squaraine aggregates. Furthermore, these results encourage the application of squaraine-based aggregates in next generation systems driven by molecular excitons.},
doi = {10.1021/acs.jpcb.0c06480},
url = {https://www.osti.gov/biblio/1670511}, journal = {The Journal of Physical Chemistry B},
issn = {1520--6106},
number = ,
volume = ,
place = {United States},
year = {2020},
month = {10}
}

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