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).

Combination of Two Colorless Fluorophores for Full-Color Red-Green-Blue Luminescence

“…Considering that different polarities and viscosities of various environments may cause uneven mixing of the mixture system composed of DPAC and DSA, a single-molecule DLA was further synthesized by covalently connecting DPAC and DSA. 48 This molecule showed obvious dual-emission characteristics, and the blue emission peak had a considerable solvation effect (Figure 6), which are similar to the rules of the previous mixture in Figure 5. According to the change of CIE coordinates corresponding to the emission wavelength of DLA in different solvents (Figure S8), the CIE coordinates corresponding to the single-molecule DLA fluorescence emission in various polar solvents also had a wide distribution.…”

Dual Emission: Classes, Mechanisms, and Conditions

“…[17] Interestingly,t he slow planarization in ESCE compounds has been recently used to dynamically regulate energy/electron transfer processes in D-A dyads with DPAC as the donor moiety. [122] 3.5. Twisted Intramolecular Charge Transfer (TICT)…”

Heterogeneous Fluorescent Organohydrogel Enables Dynamic Anti‐Counterfeiting

“…Compared with the MCMA (5.19 eV), DEAN (4.61 eV) acts as the donor occupying high position of highest occupied molecular orbital (HOMO), indicating the possibility of electron transfer from naphthalimide moieties to merocyanine moieties. [23] The PL mapping spectrum (Figure 2D) reveals that there is only a green emission center in the p(DMA-DEAN)/p(SMA-SPMA) organohydrogel (left). Relatively, UV light (365 nm) triggered ring-opening process of spiropyran moieties leads the emergence of red emission centers and the weakening of green emission centers in the organohydrogel (right).…”