Li, Wenhui and Li, Jiayu and Kurganskii, Ivan and Ye, Kaiyue and Zhang, Xue and Zhao, Jianzhang and Li, Ming-De and Dick, Bernhard and Fedin, Matvey (2025) Photophysical properties of perylenebisimide derivatives studied by time-resolved transient optical and electron paramagnetic resonance spectroscopy. JOURNAL OF CHEMICAL PHYSICS, 163 (16): 164304. ISSN 0021-9606, 1089-7690
Full text not available from this repository. (Request a copy)Abstract
We studied the intersystem crossing (ISC) of the neutral, monoanionic, and dianionic forms of two perylenebisimide PBI derivatives with twisted pi-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 tau(T) = 3.6 mu s), 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 pi-conjugation framework of a molecular structure does not necessarily induce ISC, and excited state energy level matching of S-1/T-n 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.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | TRIPLET EXCITED-STATE; RADICAL-ANIONS; BODIPY DERIVATIVES; SINGLET OXYGEN; BISIMIDE; PHOTOSENSITIZERS; REDUCTION; DELOCALIZATION; RE(BPY)(CO)(3); PHOTOOXIDATION; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry III - Physical Chemistry (Molecular Spectroscopy and Photochemistry) > Prof. Dr. Bernhard Dick |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 23 Apr 2026 12:42 |
| Last Modified: | 23 Apr 2026 12:42 |
| URI: | https://pred.uni-regensburg.de/id/eprint/67529 |
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