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Achieving Dual-Emissive and Time-Dependent Evolutive Organic Afterglow by Bridging Molecules with Weak Intermolecular Hydrogen Bonding
摘要： It is discovered that “bridging” traditional persistent room-temperature phosphorescence (pRTP) dibenzofuran moieties by intermolecular hydrogen bonding can induce interesting photophysical properties. The light-emitting material 4-(4-((4-methoxyphenyl)sulfonyl)phenyl)dibenzo[b,d]furan (SOBF-OMe) is synthesized and excitingly shows novel dual-emissive afterglow material properties in which orange pRTP (at ≈580 nm, 627 ms) from the dibenzofuran moiety and another blue ultralong intermolecular charge transfer emission (≈476 nm, 204 ms, with TADF characteristics) can be detected. Due to the different decay lifetimes, the ratio of the two afterglow emission bands continuously changes. Accordingly, the emission colors are unusually tuned gradually from cold-white to orange during the afterglow decay process. The blue afterglow emission, which relates to intermolecular interactions, is sensitive to mechanical stimuli and the afterglow emission properties of SOBF-OMe (single-emissive or dual-emissive) can easily be manipulated by grinding/fuming. This single-component material is a rare example of a light-emitting compound showing dual-emissive and real-time changing afterglow properties in which a rational bridging strategy via weak intermolecular hydrogen bonding is utilized.
关键词： afterglow emission,dual-emissive,thermally activated delayed fluorescence,intermolecular charge transfer,hydrogen bonds
更新于2025-09-19 17:15:36
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Counteranion-Triggered and Excitation-Dependent Chemopalette Effect in a Supramolecular Dual-Emissive System Based on Cu <sub/>3</sub> Pz <sub/>3</sub>
摘要： Three Cu3Pz3-based isostructural complexes (Cu3L3)2(CuX)2 (labeled as 1-ClO4, 1-NO3, and 1-Br, where X = ClO4?, NO3?, and Br?, respectively) were prepared by solvothermal reactions of an angular bifunctional pyridyl?pyrazole ligand, 4-(pyridin-4′-ylthio)-3,5-dimethyl-1H-pyrazole (HL), with Cu(ClO4)2, Cu(NO3)2, and CuBr, respectively. Pyrazolate (Pz) groups are highly specific to form planar trinuclear Cu3Pz3 units. Two Cu3L3 units are further connected by two CuX units through NPy?Cu?NPy (Py = 4-pyridyl) bonds to form an octanuclear chairlike molecule (Cu3L3)2(CuX)2, which then self-assembles through intertrimeric cuprophilicity to construct chainlike supraaggregates featuring two luminophores, [Cu3Pz3]2 and CuPy2X. With different counteranions (ClO4?, NO3?, and Br?), the complexes give off various emissions from red to green upon UV irradiation. 1-ClO4 and 1-NO3 show only low-energy (LE) orange (λemmax = 585 nm) and red (λemmax = 640 nm) emissions, while 1-Br exhibits excitation-dependent (260?360 nm) emissions from yellow to green due to variation in the relative intensities of two resolvable emissions, high energy (HE, λemmax = 520 nm) and LE (λemmax = 630 nm). The dual emissions are assigned to 3CC (LE states) based on excimeric [Cu3Pz3]2 units and 3XLCT/3MLCT (HE states) based on CuPy2X units. This work realizes a chemopalette effect through regulations of the counteranion and excitation energy in a dual-emissive system. It provides valuable insights into the nature of dual-emissive materials and the further investigation of the photophysical mechanism in such a system.
关键词： Cu3Pz3-based complexes,excitation-dependent,dual-emissive system,counteranion-triggered,chemopalette effect
更新于2025-09-04 15:30:14