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Title: New Ligand Design Provides Delocalization and Promotes Strong Absorption throughout the Visible Region in a Ru(II) Complex

Abstract

The new Ru(II)–anthraquinone complex [Ru(bpy) 2(qdpq)](PF 6) 2 (Ru-qdpq; bpy = 2,2'-bipyridine; qdpq = 2,3-di(2-pyridyl)naphtho[2,3-f]quinoxaline-7,12-quinone) possesses a strong 1MLCT Ru → qdpq absorption with a maximum at 546 nm that tails into the near-IR and is significantly red-shifted relative to that of the related complex [Ru(bpy) 2(qdppz)](PF 6) 2 (Ru-qdppz; qdppz = naphtho[2,3-a]dipyrido[3,2-h:2',3'-f]phenazine-5,18-dione), with λ max = 450 nm. Ru-qdppz possesses electronically isolated proximal and distal qdppz-based excited states; the former is initially generated and decays to the latter, which repopulates the ground state with τ = 362 ps. In contrast, excitation of Ru-qdpq results in the population of a relatively long-lived (τ = 19 ns) Ru(dπ) → qdpq(π*) 3MLCT excited state where the promoted electron is delocalized throughout the qdpq ligand. Ultrafast spectroscopy, used together with steady-state absorption, electrochemistry, and DFT calculations, indicates that the unique coordination modes of the qdpq and qdppz ligands impart substantially different electronic communication throughout the quinone-containing ligand, affecting the excited state and electron transfer properties of these molecules. As a result, these observations create a pathway to synthesize complexes with red-shifted absorptions that possess long-lived, redox-active excited states that are useful for various applications, including solar energy conversion and photochemotherapy.

Authors:
 [1]; ORCiD logo [1]; ORCiD logo [1]
  1. The Ohio State Univ., Columbus, OH (United States). Department of Chemistry and Biochemistry
Publication Date:
Research Org.:
The Ohio State Univ., Columbus, OH (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1430217
Grant/Contract Number:  
SC0010542
Resource Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 140; Journal Issue: 1; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Whittemore, Tyler J., White, Travis A., and Turro, Claudia. New Ligand Design Provides Delocalization and Promotes Strong Absorption throughout the Visible Region in a Ru(II) Complex. United States: N. p., 2017. Web. doi:10.1021/jacs.7b09389.
Whittemore, Tyler J., White, Travis A., & Turro, Claudia. New Ligand Design Provides Delocalization and Promotes Strong Absorption throughout the Visible Region in a Ru(II) Complex. United States. doi:10.1021/jacs.7b09389.
Whittemore, Tyler J., White, Travis A., and Turro, Claudia. Wed . "New Ligand Design Provides Delocalization and Promotes Strong Absorption throughout the Visible Region in a Ru(II) Complex". United States. doi:10.1021/jacs.7b09389. https://www.osti.gov/servlets/purl/1430217.
@article{osti_1430217,
title = {New Ligand Design Provides Delocalization and Promotes Strong Absorption throughout the Visible Region in a Ru(II) Complex},
author = {Whittemore, Tyler J. and White, Travis A. and Turro, Claudia},
abstractNote = {The new Ru(II)–anthraquinone complex [Ru(bpy)2(qdpq)](PF6)2 (Ru-qdpq; bpy = 2,2'-bipyridine; qdpq = 2,3-di(2-pyridyl)naphtho[2,3-f]quinoxaline-7,12-quinone) possesses a strong 1MLCT Ru → qdpq absorption with a maximum at 546 nm that tails into the near-IR and is significantly red-shifted relative to that of the related complex [Ru(bpy)2(qdppz)](PF6)2 (Ru-qdppz; qdppz = naphtho[2,3-a]dipyrido[3,2-h:2',3'-f]phenazine-5,18-dione), with λmax = 450 nm. Ru-qdppz possesses electronically isolated proximal and distal qdppz-based excited states; the former is initially generated and decays to the latter, which repopulates the ground state with τ = 362 ps. In contrast, excitation of Ru-qdpq results in the population of a relatively long-lived (τ = 19 ns) Ru(dπ) → qdpq(π*) 3MLCT excited state where the promoted electron is delocalized throughout the qdpq ligand. Ultrafast spectroscopy, used together with steady-state absorption, electrochemistry, and DFT calculations, indicates that the unique coordination modes of the qdpq and qdppz ligands impart substantially different electronic communication throughout the quinone-containing ligand, affecting the excited state and electron transfer properties of these molecules. As a result, these observations create a pathway to synthesize complexes with red-shifted absorptions that possess long-lived, redox-active excited states that are useful for various applications, including solar energy conversion and photochemotherapy.},
doi = {10.1021/jacs.7b09389},
journal = {Journal of the American Chemical Society},
number = 1,
volume = 140,
place = {United States},
year = {2017},
month = {12}
}

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Cited by: 9 works
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Figures / Tables:

Figure 1 Figure 1: Schematic representation of Ru(II) complexes.

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Works referencing / citing this record:

Long-lived MLCT states for Ru( ii ) complexes of ferrocene-appended 2,2′-bipyridines
journal, January 2019

  • Barnsley, Jonathan E.; Findlay, James A.; Shillito, Georgina E.
  • Dalton Transactions, Vol. 48, Issue 41
  • DOI: 10.1039/c9dt02025j

The odd–even effect of alkyl chain in organic room temperature phosphorescence luminogens and the corresponding in vivo imaging
journal, January 2019

  • Yang, Jie; Gao, Heqi; Wang, Yunsheng
  • Materials Chemistry Frontiers, Vol. 3, Issue 7
  • DOI: 10.1039/c9qm00108e

Long-lived MLCT states for Ru( ii ) complexes of ferrocene-appended 2,2′-bipyridines
journal, January 2019

  • Barnsley, Jonathan E.; Findlay, James A.; Shillito, Georgina E.
  • Dalton Transactions, Vol. 48, Issue 41
  • DOI: 10.1039/c9dt02025j

The odd–even effect of alkyl chain in organic room temperature phosphorescence luminogens and the corresponding in vivo imaging
journal, January 2019

  • Yang, Jie; Gao, Heqi; Wang, Yunsheng
  • Materials Chemistry Frontiers, Vol. 3, Issue 7
  • DOI: 10.1039/c9qm00108e

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