Multi-state Photoswitching in Thienoquinoid-Based Fluorescent Trithiophenes

Nishimura, Rio; Hecht, Stefan; Saito, Shohei et al.

Chemistry - A European Journal, 2026

Number of Access:13（2026-08-12 07:45 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/106011

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Title
Multi-state Photoswitching in Thienoquinoid-Based Fluorescent Trithiophenes
Creator
CreatorName
Nishimura, Rio
CreatorName
Hecht, Stefan
NRID
1000030580071 1000030580071
ORCID
0000-0003-1863-9956 0000-0003-1863-9956
researchmap permalink
read0156671 read0156671
Scopus Author ID
9270732400 9270732400
CreatorName
Saito, Shohei
NRID
1000040468145 1000040468145
ORCID
0000-0001-7270-1234 0000-0001-7270-1234
researchmap permalink
ken1-yamashi ken1-yamashi
Scopus Author ID
35792834600 35792834600
CreatorName
Yamashita, Ken ichi
Subject
conjugation
fluorescence
geometrical isomer
photoisomerization
thienoquinoid
Description
Nishimura R., Hecht S., Saito S., et al. Multi-state Photoswitching in Thienoquinoid-Based Fluorescent Trithiophenes. Chemistry - A European Journal , (2026); https://doi.org/10.1002/chem.71423.
Abstract
Achieving multi-site photoisomerization within a single π-conjugated scaffold while retaining luminescent functionality remains a formidable challenge, as electronic coupling between isomerizable units typically promotes intramolecular energy transfer that suppresses sequential switching, and the additional nonradiative pathways inherent to multiple isomerizable bonds further impede emissive behavior. Herein, we report a methine-bridged trithiophene bearing 2,6-dichlorophenyl substituents, in which two C═C double bonds embedded in a thienoquinoid framework undergo photoisomerization to afford three interconvertible geometrical isomers (ZZ, EZ, and EE). The steric constraint imposed by the ortho-chloro substituents suppresses nonradiative torsional relaxation, yielding a fluorescence quantum yield of 0.40 for the ZZ-isomer in cyclohexane, which decreases upon photoisomerization to the EZ- and EE-isomers—a significant enhancement over the corresponding derivative lacking ortho-substituents on the aryl groups, accompanied by a markedly reduced Stokes shift. The photostationary state composition varies systematically with the irradiation wavelength, primarily reflecting differences in the molar absorption coefficients of the three isomers, thereby enabling wavelength-selective multi-state control over isomer distributions inaccessible under thermodynamic equilibrium. Fluorescence lifetime measurements revealed isomer-dependent excited-state lifetimes, confirming that molecular geometry governs the photophysical properties within this conjugated framework. This study establishes a molecular design strategy for luminescent multi-state photoswitches applicable to multi-level optical information processing.
Publisher
John Wiley and Sons Inc
Source Title
Chemistry - A European Journal
Date of Issued
2026-07-17
Language
English
Handle URL
https://hdl.handle.net/11094/106011
PISSN
09476539
eISSN
15213765
Relation.isIdenticalTo
DOI (Publisher Version)
https://doi.org/10.1002/chem.71423
Access Rights
open access
CopyRight
This article is licensed under a Creative Commons Attribution 4.0 International License.
oaire:version
Version of Record
Category
学術雑誌論文 Journal Article