EPR of photoexcited triplet-state acceptor porphyrins

Abstract: The photoexcited triplet states of porphyrin architectures are of significant interest in a wide range of fields including molecular wires, nonlinear optics, and molecular spintronics. Electron paramagnetic resonance (EPR) is a key spectroscopic tool in the characterization of these transient paramagnetic states singularly well suited to quantify spin delocalization. Previous work proposed a means of extracting the absolute signs of the zero-field splitting (ZFS) parameters, D and E, and triplet sublevel populations by transient continuous wave, hyperfine measurements, and magnetophotoselection. Here, we present challenges of this methodology for a series of meso-perfluoroalkyl-substituted zinc porphyrin monomers with orthorhombic symmetries, where interpretation of experimental data must proceed with caution and the validity of the assumptions used in the analysis must be scrutinized. The EPR data are discussed alongside quantum chemical calculations, employing both DFT and CASSCF methodologies. Despite some success of the latter in quantifying the magnitude of the ZFS interaction, the results clearly provide motivation to develop improved methods for ZFS calculations of highly delocalized organic triplet states

Location
Deutsche Nationalbibliothek Frankfurt am Main
Extent
Online-Ressource
Language
Englisch
Notes
The journal of physical chemistry. C, Nanomaterials and interfaces. - 125, 21 (2021) , 11782-11790, ISSN: 1932-7455

Event
Veröffentlichung
(where)
Freiburg
(who)
Universität
(when)
2022
Creator
Redman, Ashley J.
Moise, Gabriel
Richert, Sabine
Peterson, Erin J.
Myers, William K.
Therien, Michael J.
Timmel, Christiane R.

DOI
10.1021/acs.jpcc.1c03278
URN
urn:nbn:de:bsz:25-freidok-2305754
Rights
Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
Last update
25.03.2025, 1:44 PM CET

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Associated

Time of origin

  • 2022

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