Diversified Excited‐State Relaxation Pathways of Donor–Linker–Acceptor Dyads Controlled by a Bent‐to‐Planar Motion of the Donor. Issue 42 (17th August 2020)

• Record Type: Journal Article
• Authors: Sun, Guangchen; Wei, Yu‐Chen; Zhang, Zhiyun; Lin, Jia‐An; Liu, Zong‐Ying; Chen, Wei; Su, Jianhua; Chou, Pi‐Tai; Tian, He
• Is Part Of: Angewandte Chemie international edition. Volume 59:Issue 42(2020)
• Page Start: 18611
• Page End: 18618
• Publication Date: 2020-08-17
• Subjects: donor–linker–acceptor dyads -- electron transfer -- energy transfer -- fluorescence -- photoinduced structural planarization; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202005466
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Herein, we introduce the cyclic 8π‐electron (C8π) molecule N, N ′‐diaryl‐dihydrodibenzo[ a, c ]phenazine (DPAC ) as a dual‐functional donor to establish a series of new donor–linker–acceptor (D–L–A) dyads DLA1 –DLA5 . The excited‐state bent‐to‐planar dynamics of DPAC regulate the energy gap of the donor, while the acceptors A1 –A5 are endowed with different energy gaps and HOMO/LUMO levels. As a result, the rate and efficiency of the excited‐state electron transfer vs. energy transfer can be finely harnessed, which is verified via steady‐state spectroscopy and time‐resolved emission measurements. This comprehensive approach demonstrates, for the first time, the manifold of excited‐state properties governed by bifunctional donor‐based D–L–A dyads, including bent‐to‐planar, photoinduced electron transfer (PET) from excited donor to acceptor (oxidative‐PET), fluorescence resonance energy transfer (FRET), bent‐to‐planar followed by electron transfer (PFET), and PET from donor to excited acceptor (reductive‐PET). Abstract : A bent/planar dual‐channel donor was introduced to establish new donor–linker–acceptor (D–L–A) dyads in which the excited‐state bent‐to‐planar structure relaxation of the donor can be used as a clock to harness the electron/energy‐transfer processes. Several new D–L–A structures were designed and synthesized by tuning the energy gaps and frontier‐orbital levels of the acceptors.