Diversified Excited‐State Relaxation Pathways of Donor–Linker–Acceptor Dyads Controlled by a Bent‐to‐Planar Motion of the Donor

Abstract

Herein, we introduce the cyclic 8p-electron (C8p) molecule N,N'-diaryl-dihydrodibenzo[a,c]phenazine (DPAC) as a dual-functional donor to establish a series of new donorlinker-acceptor (D-L-A) dyads DLA1-DLA5. The excitedstate 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-toplanar, 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).

A Bright Deep-Red AIEgen with Locked Noncoplanar Conformation for Lipid Droplet-Specific Imaging

“…3,4 Therefore, precisely tuning the conformation is highly desirable but exceptionally challenging based on the fact that "easy to change" can also be described as "hard to control". 5,6 Among those properties that are strictly related to conformation, 7,8 fluorescence holds its unique features such as low energy consumption, stimuli responsiveness, and non-invasiveness exhibiting broad applications in electroluminescence devices, 9,10 chemo/bio-sensors, 11,12 and bioimaging etc. 13,14 The luminescence property of a single molecule generally relies on the excited state features such as energy level distribution, intersystem crossing, and exciton decay pathway etc.…”