On the Importance of Electronic Symmetry for Triplet State Delocalization
Abstract
The influence of electronic symmetry on triplet state delocalization in linear zinc porphyrin oligomers is explored by electron paramagnetic resonance techniques. Using a combination of transient continuous wave and pulse electron nuclear double resonance spectroscopies, it is demonstrated experimentally that complete triplet state delocalization requires the chemical equivalence of all porphyrin units. These results are supported by density functional theory calculations, showing uneven delocalization in a porphyrin dimer in which a terminal ethynyl group renders the two porphyrin units inequivalent. When the conjugation length of the molecule is further increased upon addition of a second terminal ethynyl group that restores the symmetry of the system, the triplet state is again found to be completely delocalized. Finally, the observations suggest that electronic symmetry is of greater importance for triplet state delocalization than other frequently invoked factors such as conformational rigidity or fundamental length-scale limitations.
- Authors:
-
- Centre for Advanced Electron Spin Resonance (CAESR), University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
- Department of Chemistry, Duke University, French Family Science Center, 124 Science Drive, Durham, North Carolina 27708, United States
- Department of Physics, Saint Joseph’s University, 5600 City Avenue, Philadelphia, Pennsylvania 19131, United States
- Publication Date:
- Research Org.:
- Duke Univ., Durham, NC (United States); Univ. of Oxford, Oxford (United Kingdom)
- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); European Research Counsel (ERC)
- OSTI Identifier:
- 1355067
- Alternate Identifier(s):
- OSTI ID: 1426483
- Grant/Contract Number:
- SC0001517; 320969
- Resource Type:
- Published Article
- Journal Name:
- Journal of the American Chemical Society
- Additional Journal Information:
- Journal Name: Journal of the American Chemical Society Journal Volume: 139 Journal Issue: 15; Journal ID: ISSN 0002-7863
- Publisher:
- American Chemical Society
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Citation Formats
Richert, Sabine, Bullard, George, Rawson, Jeff, Angiolillo, Paul J., Therien, Michael J., and Timmel, Christiane R. On the Importance of Electronic Symmetry for Triplet State Delocalization. United States: N. p., 2017.
Web. doi:10.1021/jacs.7b01204.
Richert, Sabine, Bullard, George, Rawson, Jeff, Angiolillo, Paul J., Therien, Michael J., & Timmel, Christiane R. On the Importance of Electronic Symmetry for Triplet State Delocalization. United States. https://doi.org/10.1021/jacs.7b01204
Richert, Sabine, Bullard, George, Rawson, Jeff, Angiolillo, Paul J., Therien, Michael J., and Timmel, Christiane R. Tue .
"On the Importance of Electronic Symmetry for Triplet State Delocalization". United States. https://doi.org/10.1021/jacs.7b01204.
@article{osti_1355067,
title = {On the Importance of Electronic Symmetry for Triplet State Delocalization},
author = {Richert, Sabine and Bullard, George and Rawson, Jeff and Angiolillo, Paul J. and Therien, Michael J. and Timmel, Christiane R.},
abstractNote = {The influence of electronic symmetry on triplet state delocalization in linear zinc porphyrin oligomers is explored by electron paramagnetic resonance techniques. Using a combination of transient continuous wave and pulse electron nuclear double resonance spectroscopies, it is demonstrated experimentally that complete triplet state delocalization requires the chemical equivalence of all porphyrin units. These results are supported by density functional theory calculations, showing uneven delocalization in a porphyrin dimer in which a terminal ethynyl group renders the two porphyrin units inequivalent. When the conjugation length of the molecule is further increased upon addition of a second terminal ethynyl group that restores the symmetry of the system, the triplet state is again found to be completely delocalized. Finally, the observations suggest that electronic symmetry is of greater importance for triplet state delocalization than other frequently invoked factors such as conformational rigidity or fundamental length-scale limitations.},
doi = {10.1021/jacs.7b01204},
journal = {Journal of the American Chemical Society},
number = 15,
volume = 139,
place = {United States},
year = {2017},
month = {4}
}
https://doi.org/10.1021/jacs.7b01204
Web of Science
Figures / Tables:

Works referencing / citing this record:
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