查看更多>>摘要：Developing multi-stimuli-responsive chromic materials has been intensively pursued as smart materials for rewritable paper, smart windows and anti-counterfeiting applications. Herein, a metastable-state photoacid, a protonated-merocyanine form of a spiropyran, was incorporated into a zirconium(IV)-based UiO-topological metal organic framework (MOF) material (form PAH-MOF) for multi-stimuli-responsive chromic materials. Photoacid on the framework of PAH-MOF adopts a stable merocyanine form. And PAH-MOF shows multistimuli-responsive chromism towards heating, different solvents and acids. Despite the PAH-MOF being photo-inactive in the solid state, the acidified PAH-MOF suspensions exhibit excellent visible light induced photochromism in water and ethanol. In addition, a distinct fluorescence change along with the color change is recognized, revealing a potential application in anti-counterfeiting. Our findings will help better understand the effects of MOFs on isomerization of spiropyran derivatives.
查看更多>>摘要：As reservoirs of neutral lipids for energy storage to drive energy-demanding processes, lipid droplets (LDs) play an important role in regulating numerous cellular functions. In addition, LDs are crucial in the progression of some diseases, such as cancer, atherosclerosis, fatty liver disease, hyperlipidemia, diabetes, and neurodegeneration. In clinical diagnosis and biomedical research, fluorescence bioimaging of LDs for the dynamic localization and real-time analysis is commonly utilized. The aggregation-induced emission luminogens (AIEgens) are promising candidates for LD imaging owing to their high signal-to-noise (S/N) ratio, "lit up" character, excellent photostability, and good biocompatibility. In this review, the design principles and various kinds of AIEgens (reactive AIEgens, red/NIR emission AIEgens, two-photon AIEgens, AIE + ESIPT based luminogens, organoboron materials and other AIEgens) for LDs imaging, LDs dynamic detection, and imaging of other lipidrich organisms are summarized. We anticipate that this review can stimulate further expanding more AIEgens for LDs imaging and detection.
查看更多>>摘要：Two type luminophore 1 and 2, with the same triphenylamine (TPA) and malonitrile-functionalized 1,3-diaryl pyrazole (MDP) units but with different pi-conjugated spacer, were designed and synthesized. The crystals solid-state emission behavior and mechanical stimuli-responsive fluorescence characteristics of 1 and 2 were investigated. Interestingly, the fluorophores 1 and 2 exhibited yellow-green and yellow crystals solid-state fluorescent, respectively. Furthermore, 1 and 2 also exhibited obvious mechanochromic fluorescence behavior with repeated four cycles. Compared to 1 with an 80 nm red-shift, 2 is more sensitive to mechanical stimuli and exhibits a large red-shift emission of 85 nm. The powder XRD experiments demonstrated that the mechanochromic fluorescence behavior of 1 and 2 were related to the morphology transformation from crystalline state to amorphous state. In addition, based on the MDP moiety as I- receptor, 1 and 2 were qualified for sensing of I with low limit of detection (89.0 nM, 149.9 nM). The biosensing of I- based on the better detection performance of the probe 1 was achieved in A549 cells and zebrafish. These results certify the great potential of MDP as a strong electron-deficient unit for designing D-A type mechanochromic fluorescence materials and biosensors for the detection of I- in organism.
查看更多>>摘要：Developing multitask smart materials is in high demand and remains challenging in the organic fluorophore research field. In this work, we designed and synthesized a series of tetraphenylethylene modified fluorophores (TPEN, TPEH, TPEF, TPEIZ, TPECN) with D-pi-A configuration and various terminal substituents, whose packing structures in the solid state were finely manipulated and revealed by single-crystal structure analysis. These materials showed excellent aggregation-induced emission (AIE) and mechanofluorochromism (MFC) properties. The fluorescence peaks of TPEH, TPEF, TPEIZ and TPECN were gradually red-shifted with the change of solid fluorescence quantum yields (Phi(F)) under grinding, derived by the different molecular conformation and packing between crystalline and amorphous states. Notably, thanks to the high sensitivity to force, TPEH and TPEF exhibited high-contrast turn-on MFC property with obviously increase of Phi(F). Meanwhile, TPEF achieved the quantitative detection of pressure in turn-on modal due to the special molecular packing induced by the F atom. Additionally, TPEH, TPEF, TPEIZ and TPECN were applied for the detection of picric acid (PA) and the limit of detection for the four materials was 7.58 mu M, 458 nM, 634 nM and 4.62 mu M, respectively. The mechanism was attributed to the synergistic effects of coulombic forces and protonation/hydrogen bonding interactions and the photoinduced electron transfer (PET) process. This work provides a new scope for rational design of highly sensitive multitask smart materials for low-pressure and PA detection.
查看更多>>摘要：Though a small number of binders and probes towards human telomeric multimeric G-quadruplexes have been reported to use the tumor detection and therapy in recent years, their detection in visible region and medium antitumor activity limit the development in the research of antitumor drugs. Here, three new malachite green (MG) dimers 1a~c with the different-length polyether linkers have been synthesized to study their NIR visualization towards human telomeric dimeric G-quadruplexes (G2T1) and antitumor activity. The linkers of these dimers could optimize the imaging and binding selectivity for G2T1. Dimer 1c with the longest polyether linker showed higher binding and stabilization towards G2T1 over monomeric G-quadruplexes and ds DNA. More importantly, dimer 1c exhibited selective NIR imaging towards G2T1 in vitro and in cells. In addition, dimer 1c also showed excellent cytotoxicity (IC50 < 1.0 mu M). This study is one of the few research reports on G2T1 probes combined with NIR imaging and the excellent antitumor activity. It gives us to provide a new idea to develop the antitumor drugs with high efficiency and the less side effect by controlling the drug delivery under the guidance of NIR imaging towards G2T1.
查看更多>>摘要：In this work, a novel approach to realizing the electrically induced coloration of polymer-stabilized cholesteric liquid crystal (LC) films with broadband reflection capability for smart windows was reported. Only starting common materials and an established preparation method were used. The polymer-stabilized cholesteric LC films with broadband reflection capability were prepared via the method of polymerization-induced pitch gradient. After doping with a commercial ionic liquid which served as the supporting electrolyte in the system, the initial broadband reflection capability of the polymer-stabilized cholesteric LCs film was not damaged, and the film can change into a colored state from a colorless state under a low direct current (DC) voltage. The color of the polymer-stabilized cholesteric LCs also can gradually disappear after the removal of the field despite the slow response rate. The as-prepared polymer-stabilized cholesteric LCs in this work not only can be applied in the energy-saving smart windows and thermal management for buildings, but also presented the performance of electrically induced coloration under a low voltage. This work is expected to provide a creative approach for the preparation of electrochromic energy-saving smart windows.
查看更多>>摘要：We have designed and synthesized three thermally activated delayed fluorescent (TADF) emitters as 2-phenypyrimidine (PPM)-10H-spiro[acridan-9,9 '-fluorene] (SPAc) hybrids, collectively named X-SPAc-PPM, featured an asymmetrical D-A-D molecular architecture, through the para-/ortho-, para-/meta-, and para-/ortho- positions of the phenyl spacer in SPAc with PPM unit. The effect of the hybrid connection at ortho-, meta-, or para-positions on the different properties of pyrimidine derivatives is detailed discussed. The investigation suggests that the localization of the HOMO has the preferential choice tendency in asymmetric X-SPAc-PPM, and following the order of para-position arms, ortho-position arms, which adjust effectively the intramolecular charge transfer (ICT) character between SPAc and PPM unit. As a result, three isomers have the smaller Delta EST of 0.05-0.16 eV, and exhibit obvious TADF character. In addition, p,m-SPAc-PPM endowed its OLED device with impressive performance, including the maximum external quantum efficiency around 25.1%, and reduced efficiency roll-offs. The smaller Delta EST, over 25% EQE, and lower efficiency roll-offs of three isomeric X-SPAc-PPM emitters further prove the great potential of asymmetrical design strategy with the same donor for highly efficient TADF devices.
查看更多>>摘要：Carbazole is a weak electron donor suitable to construct blue thermally activated delayed fluorescence (TADF) emitters, but the less repulsion effect of its five-member-ring structure can't guarantee the frontier molecular orbital separation and TADF feature. A group of carbazole-pi-triazine based blue fluorescence emitters is designed by introducing the steric hindrance groups with different electronic properties at the donor or pi-bridge. When electron-withdrawing pyridyl with moderate steric hindrance is introduced to the 1-site of 3,6-Di-tert-butyl-9Hcarbazole, PyBuCz-TRZ and PyBuCz-MeTRZ gain the blue-shifted TADF. The observed charge transfer triplet excited state within the donor ((CTD)-C-3) between carbazole and pyridyl units has different spatial orbital angular momentum and allowed spin-orbit coupling (SOC) with the charge transfer singlet excited state ((CT)-C-1) of the whole molecule from carbazole donor to triazine acceptor, thus, acting as the media state to facilitate efficient multi-channel reverse intersystem crossing (RISC) process. This is the first time to introduce an electronwithdrawing group into the 1-position of carbazole donors to construct TADF molecules, not only achieving the blue-shifted TADF at 455 nm but also improving the external quantum efficiency to 15.3% in organic lightemitting diodes. This donor strategy should be valid to design more blue TADF materials.
查看更多>>摘要：In this study, novel multifunctional durable intelligent hybrid pigments with allochroic, antibacterial, and superhydrophobic properties were facilely fabricated by a cleaner mechanochemical method, in which palygorskite was initially modified with cetyltrimethylammonium bromide to anchor curcumin by semidry grinding, and subsequently coated with organosilanes by one-step modification via semidry grinding. The obtained hybrid pigments were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmittance electron microscopy, EDS mapping, X-ray photoelectron spectroscopy, and the Brunauer-Emmett-Teller method. The density functional theory calculation was also performed to further explore the possible interaction among curcumin and organo-palygorskite. The results confirmed that curcumin was loaded on organo-palygorskite via electrostatic and hydrogen bond interactions. Due to the synergistic effect of the organic modification, the obtained hybrid pigments exhibited excellent antibacterial activity against Staphylococcus aureus with minimal inhibitory concentrations of 0.5 mg/mL. Furthermore, curcumin-loaded organo-palygorskite presented excellent thermal and chemical stability after subsequent modification with organosilanes at different heating temperatures and chemical reagents. The organo-palygorskite/curcumin@polymerized organosilane composites could intelligently monitor fish spoilage in real time based on the reversible allochroic properties of the loaded curcumin. Thus, hybrid pigments are expected to design promising multifunctional food packaging materials with allochroic, antibacterial, and superhydrophobic properties.
查看更多>>摘要：A regioisomer of 2,7-bis(4,6-diphenyl-1,3,5-triazin-2-yl)-9,9' -spirobi[fluorene] (m-SBFTrz), 3,6-bis(4,6-diphenyl-1,3,5-triazin-2-yl)-9,9' -spirobi[fluorene] (p-SBFTrz) was developed as a high triplet energy electron transport material by engineering the substitution position of diphenyltriazine to the spirobifluorene core. The p-SBFTrz showed great potential as an electron transport and exciton blocking materials in various devices such as thermally activated delayed fluorescence organic light-emitting diodes (OLEDs) and phosphorescence OLEDs due to increased triplet energy. A large improvement of the external quantum efficiency was achieved using the p-SBFTrz instead of m-SBFTrz by completely suppressing exciton quenching.
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Elsevier