Photophysical properties of perylenebisimide derivatives studied by time-resolved transient optical and electron paramagnetic resonance spectroscopy

Photophysical properties of perylenebisimide derivatives studied by time-resolved transient optical and electron paramagnetic resonance spectroscopy Full article

Journal

The Journal of Chemical Physics
ISSN: 0021-9606

Output data

Year: 2025, Volume: 163, Number: 16, Article number : 164304, Pages count : 17 DOI: 10.1063/5.0277710

Tags

Zero field splitting, Transient-absorption spectroscopy, Electron paramagnetic resonance spectroscopy, Photochemistry, Triplet state

Authors

Li Wenhui ¹ , Li Jiayu ² , Kurganskii Ivan ^3,5 , Ye Kaiyue ¹ , Zhang Xue ¹ , Zhao Jianzhang ¹ , Li Ming-De ² , Dick Bernhard ⁴ , Fedin Matvey ^3,5

Affiliations

1	State Key Laboratory of Fine Chemicals, Frontier Science Center of Smart Materials, School of Chemical Engineering, Dalian University of Technology 1 , 2 Ling-Gong Road, Dalian 116024,
2	Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University 2 , Shantou 515063,
3	International Tomography Center, SB RAS Institutskaya Str., 3A, and Novosibirsk State University 3 , Pirogova Str. 2, Novosibirsk 630090,
4	Lehrstuhl für Physikalische Chemie, Institut für Physikalische and Theoretische Chemie, Universität Regensburg, Universitätsstr. 31 4 , D-93053 Regensburg,
5	Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia

We studied the intersystem crossing (ISC) of the neutral, monoanionic, and dianionic forms of two perylenebisimide PBI derivatives with twisted π-conjugation framework in the molecular structure: one is substituted with four chloride atoms (PBI-Cl), whereas the other has a fused dimeric molecular structure (DiPBI). PBI-Cl is highly fluorescent, and no ISC was observed. However, the DiPBI shows efficient ISC (triplet state lifetime τT = 3.6 μs), supported by theoretical computation with the Herzberg–Teller effect taken into account. Time-resolved electron paramagnetic resonance spectra of the triplet state of DiPBI show that the zero field splitting (ZFS) D parameter is 778 MHz, indicating that the electron spin density is delocalized, because the ZFS D is much smaller than the triplet state of the unsubstituted PBI (D = 1303 MHz). No ISC was observed for the dianion [DiPBI]2−, whereas for [PBI-Cl]2, ISC was observed. This result infers that twisting of the π-conjugation framework of a molecular structure does not necessarily induce ISC, and excited state energy level matching of S1/Tn states may play the decisive role in ISC. These studies are helpful to fully exploit the super strong reductivity of photoexcited dianions in photocatalytic redox organic reactions due to the enhanced intermolecular electron transfer based on the long-lived triplet excited state of the dianions.

Li W. , Li J. , Kurganskii I. , Ye K. , Zhang X. , Zhao J. , Li M-D. , Dick B. , Fedin M.
Photophysical properties of perylenebisimide derivatives studied by time-resolved transient optical and electron paramagnetic resonance spectroscopy
The Journal of Chemical Physics. 2025. V.163. N16. 164304 :1-17. DOI: 10.1063/5.0277710 WOS Scopus OpenAlex

Submitted:	Apr 25, 2025
Accepted:	Sep 29, 2025
Published print:	Oct 28, 2025

Web of science:	WOS:001598887700002
Scopus:	2-s2.0-105019176490
OpenAlex:	W4415425010

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