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Excited state intramolecular single proton transfer mechanism of pigment yellow 101 in solid state: Experiment and DFT calculation
摘要： To investigate fluorescence mechanism of Pigment Yellow 101 (P. Y. 101) in solid state, three aromatic aldehyde azines (1-3) including P. Y. 101 have been synthesized and compared with each other. Results indicated that P. Y. 101 prepared by solvothermal method is actually the mixture of two polymorphs, whose molecular packing mode can be transformed into each other by recrystallizing or external stimuli such as pressure and grinding. The ESIPT properties of 1-3 were investigated by DFT/TD-DFT calculations and time-correlated single photon counting (TCSPC) technique. Both experimental and theoretical results revealed that the dual fluorescence properties of P. Y. 101 in solid state are ascribed to the excited-state intramolecular single proton transfer fluorescence emissions of two structurally different polymorphs rather than the results of the sequential or concerted excited-state intramolecular double proton transfers, which provide a potential valuable tool for developing multistimuli-responsive luminescent materials.
关键词： Aromatic aldehyde azines,DFT calculation,P. Y. 101,Excited-state intramolecular proton transfer,Polymorphs
更新于2025-11-19 16:56:35
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SwissKnife-Inspired Multifunctional Fluorescence Probes for Cellular Organelle Targeting Based on Simple AIEgens
摘要： Facile, efficient and mass production of aggregation-induced emission (AIE) luminogens (AIEgens) with excited-state intramolecular proton transfer (ESIPT) characteristics was achieved by one-step condensation reaction of 2-(hydrazonomethyl)phenol with benzaldehydes. The function of as-prepared AIEgens could be tuned easily by varying the functional group carrying on the phenyl ring of benzaldehyde just like Swiss knife handle. The suitable distance and angle of intramolecular hydrogen bond in these AIEgens endowed them with ESIPT properties, intense solid-state luminescence and large Stokes shifts (155?169 nm). These AIEgens could not only serve as biological probes showing specific targeting to lipid droplets, endoplasmic reticulum and lysosomes, respectively, but also generate reactive oxygen species upon visible light irradiation to make them promise for photodynamic therapy.
关键词： Fluorescence probes,Aggregation-induced emission,Excited-state intramolecular proton transfer,Photodynamic therapy,Organelle-targeting
更新于2025-09-23 15:23:52
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Electronically-tuned 2-(2′-Hydroxyphenyl)-4-pyrenylthiazole through Bond Energy Transfer Donor-Acceptor Couples: Sensing and Biological Applications
摘要： A novel pyrene-conjugated 2-(20-hydroxyphenyl)thiazole probe (HPTP, 1) was prepared, and its photophysical and sensing properties were investigated and compared to those of four model compounds. HPTP effectively detects CN? and glycerol in DMSO, with “turn off” at 425 nm and “turn on” at 495 nm. The sensing ability of 1 towards CN? ions in DMSO, mediated by the hydrogen bonding-induced disaggregation of aggregates, resulted in the quenching of ESIPT emission at 425 nm. By contrast, in a DMSO–glycerol mixed medium, the aggregate size increased together with the increased degree of intermolecular π–π interactions between two pyrene units located on adjacent molecules, and resulted in partial inhibition of energy/charge transfer from the pyrene unit to the thiazole unit in the excited state. Excitation energy transfer with increased photostability of the ESIPT core was effectively demonstrated in Candida albicans cell lines.
关键词： Glycerol,Pyrene,CN?,Excited state intramolecular proton transfer,2-(2’-Hydroxyphenyl)thiazole,Aggregation-induced emission
更新于2025-09-23 15:21:01
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Mechanochromism induced through the interplay between excimer reaction and excited state intramolecular proton transfer
摘要： Excited-state intramolecular proton transfer (ESIPT) and excimer formation are unimolecular and bimolecular reactions, respectively. The coupling between these two reactions has been rarely observed. Here we show the interplay between ESIPT and excimer formation in CF3-HTTH (2,2′-(thiazolo[5,4-d]thiazole-2,5-diyl)bis(4-(trifluoromethyl)phenol) solid crystal, resulting in the extensively broad multiple emissions spanning from 420 to 750 nm. Comprehensive structural, time-resolved spectroscopic, and two-photon microscopic studies of CF3-HTTH in crystal lattice unveil the pre-equilibrium ESIPT between the normal (N*) and tautomer (T*) form, for which the slow population decay and well-ordered lattice packing facilitate excimeric (E*) formation, rendering N* (460 nm), T* (520 nm) and E* (600 nm) triple emissions. In contrast, the lower degree of packing on the solid surface prohibits excimer formation, showing only the ESIPT process. The correlation between luminescence properties and packing structure sheds light on the corresponding mechanochromic effect based on molecular solid architecture and provide new insight into the aggregation-induced properties.
关键词： Solid-state emission,Excimer formation,Excited-state intramolecular proton transfer,Molecular packing,Mechanochromism
更新于2025-09-19 17:15:36
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Near-Infrared Organic Single-Crystal Nanolaser Arrays Activated by Excited-State Intramolecular Proton Transfer
摘要： Near-infrared lasing beyond 760 nm is achieved in the organic nanowire arrays made from the ESIPT-active organic molecule of (E)-3-(4-(dimethylamino)phenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one, and the dynamic intramolecular proton transfer process within ～2.5 ps is verified. The single-mode NIR lasing high-quality factor Q of ～2,340 can be achieved from a single nanowire with L = 10 mm, and the multi-mode NIR lasing with the lasing threshold of 2.2 mJ cm?2 can be achieved from a single nanowire with L = 70 mm.
关键词： Organic Single-Crystal,Near-Infrared,Nanolaser Arrays,Excited-State Intramolecular Proton Transfer
更新于2025-09-16 10:30:52
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Laser systems for time-resolved experiments at the Pohang Accelerator Laboratory X-ray Free-Electron Laser beamlines
摘要： Investigation of highly sensitive and selective fluorescent materials for transition metal ions has attracted significant interest because of their important roles in biological and environmental importances. Because the second most plentiful transition metal ion in human body, Zn2+ plays various critical roles in biological functions including neuronal signal transmission, enzymatic regulations, influencing DNA synthesis, and numerous cellular functions. In this respect, sensitive and noninvasive technique to detect free zinc ions, which are spectroscopically silent due to its 3d10 electron configurations, is one of the important research areas. However, most of the reported wavelengths of the chemosensors and their emissions are still lies in blue or green region, and only a few molecules showed red or orange emissions, which are better wavelengths in cellular bioimaging.
关键词： Zn2+ ion,Specific binding,Excited-state intramolecular proton transfer,Thiazole,Chemosensor
更新于2025-09-11 14:15:04
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Highly Fluorescent Liquid Crystals from Excited-State Intramolecular Proton Transfer Molecules
摘要： Fluorescence via excited-state intramolecular proton transfer (ESIPT) provides strong light emission with a large Stokes shift and environment-sensitive unique spectral patterns. Particular systems including 2-(2-hydroxyphenyl) benzothiazole (HBT) serve as efficient solid-state emitters with the ESIPT mechanism and aggregation-induced emission enhancement (AIEE) property, but have not been used for liquid crystalline (LC) materials. Here, rod-shaped fluorescent LCs with ESIPT characters are newly developed based on the HBT motif. The design of the targeted molecules is in line with a simple design principle: a molecule with an alkyl tail, rigid ring, and active HBT core. The LC C6Ph-HBT is highly luminescent in the solid state with an absolute fluorescence quantum yield (ΦFL) up to 0.39 and exhibits anisotropic fluorescence in its nematic LC phase. C6Ph-HBT is miscible up to 6 wt% with a conventional room-temperature (r.t.) nematic LC 4-cyano-4′-pentylbiphenyl (5CB), allowing homogeneous fluorescent r.t. LCs. The LC mixture 5CB/C6Ph-HBT shows ΦFL of 0.26 even in the nonaggregated state, and responds to an electric field with dynamic modulation of not only the optical transparency but also polarized fluorescence. The interplay of highly efficient fluorescence from ESIPT cores and their visible transparency is encouraging for future optical applications of the present molecular systems.
关键词： fluorescence,excited-state intramolecular proton transfer,calamitic mesogens,aggregation-induced emission,liquid crystals
更新于2025-09-10 09:29:36