Six novel benzimidazole‐based D‐π‐A compounds 4 a–4 f were concisely synthesized by attaching different donor/acceptor units to the skeleton of 1,3‐bis(1H‐benzimidazol‐2‐yl)benzene on its 5‐position ...through an ethynyl link. Due to the twisted conformation and effective conjugation structure, these dual‐state emission (DSE) molecules show intense and multifarious photoluminescence, and their fluorescence quantum yields in solution and solid state can be up to 96.16 and 69.82 %, respectively. Especially, for excellent photostability, obvious solvatofluorochromic and extraordinary wide range of solvent compatibility, DSE molecule 4 a is a multifunctional fluorescent probe for the visual detection of nitroaromatic compounds (NACs) with the limit of detection as low as 10−7 M. The quenching mechanism has been proved as the results of photoinduced electron transfer and fluorescence resonance energy transfer processes. Importantly, probe 4 a can sensitively detect NACs not only in real water samples, but also on 4 a‐coated strips and 4 a@PBAT thin films.
Novel benzimidazole‐based D‐π‐A fluorophores are rationally designed and concisely synthesized. Six compounds 4 a–4 f, as dual‐state emission (DSE) materials, exhibit excellent photostability, solvatofluorochromic and extraordinary wide range of solvent compatibility. Among them, the DSE material 4 a is not only reasonably developed as a multifunctional fluorescent probe for sensitive detection of nitroaromatic compounds (NACs) in aqueous system, but also processed into test strips and thin films for visual detection of NACs.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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•Five benzoxazole-based dual-state emission luminogens are concisely synthesized.•All designed DSEgens 4a-4e show solvatochromism, AIE effect and large Stokes shift.•Compound 4e ...displays splendid sensitivity towards nitroaromatic explosives (NAEs).•4e induces a turn-off response through multiple interactions after binding to NAEs.•Fluorophore 4e can be processed as portable tool for NAEs visualization detection.
Dual-state emission luminogens (DSEgens) as fluorophores emit efficiently in solution and solid forms have gained increasing concern in the field of chemical sensing. Recent efforts by our group led to the identification of DSEgens as an easy-to-visualize nitroaromatic explosives (NAEs) detection platform. However, none of the previously studied NAEs probes show effective improvement in sensitivity. Here, we designed a series of benzoxazole-based DSEgens through multiple strategies driven by theoretical calculations, revealing their improved detecting performance on NAEs. Compounds 4a-4e exhibit thermal- and photo-stability, large Stokes shift as well as sensitivity solvatochromism (except for 4a and 4b). A subtle balance between rigid conjugation and distorted conformation endows these D-A type fluorophores 4a-4e with DSE properties. Furthermore, 4d and 4e show aggregation-induced emission phenomenon caused by distorted molecular conformation and restricted intramolecular rotation. Interestingly, DSEgen 4e displays anti-interference and sensitivity towards NAEs with a detection limit of 10-8 M. It can be applied for expedient and distinct visual identification of NAEs not only in solution but also on filter paper and film, supporting this new DSEgen as reliable NAEs chemoprobe.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A highly efficient and operationally simple method for the synthesis of β-sulfinyl alkenylsulfones through a BF3·OEt2-promoted reaction of alkynes and sodium sulfinates is developed, successfully ...avoiding the complicated anhydrous treatment before the reaction and greatly simplifying the reaction conditions. As a facile and selective route to the targets, it features good functional group compatibility, mild conditions, easily available starting materials, and excellent yields. Notably, the trace water in solvent plays a key role in promoting the reaction, which provides a more practical pathway for the utilization of the BF3·OEt2 catalytic system.
In the absence of a metal catalyst and under the promotion of sodium bicarbonate, an eco‐friendly and practical protocol for the synthesis of vinyl thiocyanate derivatives through the reaction of ...3,4‐dihalo‐2(5H)‐furanones with KSCN at room temperature has been developed. This method has a broad substrate scope and is suitable for gram‐scale synthesis (up to 5 g). Importantly, it can also be used to synthesize vinyl selenocyanate derivatives.
An environmental‐friendly protocol enables the synthesis of vinyl thiocyanates and selenocyanates from 3,4‐dihalo‐2(5H)‐furanones, including low‐reactive Csp2‐Cl, substrates in the absence of a metal catalyst and under the promotion of simple inorganic base sodium bicarbonate.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Under microwave assistance, 2,6-bis(benzimidazolyl)-pyridine has been concisely synthesized and further productively converted to the functional molecule BMBPvia accessible N-alkylation reaction. For ...the introduction of alkoxyalkyl chain, this original substance BMBP with better solubility in water exhibits specific fluorescence response toward Zn2+ from colourless to blue in aqueous solution. A sequential detection for picric acid (PA) can be conducted in this following system, showing the high selectivity and sensitivity of quenching over other analogues. On the basis of the comparison with the control BMBB, a cascade sensing mechanism has been disclosed to accelerate the recognition of structure-property relationship, which is fully supported by LC-MS, 1H NMR, lifetime measurement and theoretical calculation. Noteworthily, BMBP is also readily available for practical application not only in quantitative determination of Zn2+ and PA in real water samples, but also in visible detection of two analytes in multiple forms on paper test strips, offering convenient process for low-cost, portable and versatile sensing device.
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•Concise design and synthesis of new fluorescence sensor with good water solubility.•Sequential sensing from Zn2+ to PA with “off-on-off” response in water.•Selective, sensitive and pH-tolerable sensing performance towards two analytes.•Cascade mechanism revealed by MS, 1H NMR, lifetime test and DFT calculation.•Applicable in real water samples and paper strip for sequential detection.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In the absence of metal catalysis and an additive, with ethyl acetate as a solvent at 95 °C under air atmosphere for 2 h, an eco-friendly and practical protocol for the synthesis of 4-ethylpiperazine ...derivatives through a 3,4-dihalo-2(5
H
)-furanone initiated ring-opening reaction of DABCO is developed. Satisfactory reactivity with moderate to excellent yields and 100% atom economy are observed. This potential bioactive synthon promoted ring-opening reaction is not only important for the development of new drugs, but also suitable for other cyclic tertiary amines (
e.g.
1-methylpyrrolidine) with good yields. In addition, due to the newly generated alkyl halide structural unit in the product, its application in one-pot two-step reactions with different kinds of nucleophilic reagents can be achieved as designed.
An environmental friendly protocol for metal/additive-free synthesis of potential bioactive compounds from 3,4-dihalo-2(5
H
)-furanone and DABCO is described.
Metal-free catalyzed intermolecular tandem Michael addition/cyclization has been developed for the synthesis of benzo4,5imidazo1,2-
a
pyridines from α-bromocinnamaldehyde and 2-substituted ...benzimidazoles. The reaction promoted by a simple inorganic base displays moderate to good yields and good functional group tolerance. The optical properties of some typical products have been investigated. We found that, due to the presence of the benzene ring at the C1-position of benzo4,5imidazo1,2-
a
pyridines which restricts intramolecular motion, as a new type of aggregation-induced emission (AIE) luminogen (AIEgen), they show very good solid-state fluorescence with quantum yields up to 88.80%. Importantly, the AIE performance of compound
3b
can be useful to detect the nitroaromatic explosive picric acid (PA) with a detection limit and quenching constant of 42.5 nM and 7.27 × 10
4
M
−M
, respectively.
Metal-free catalyzed intermolecular tandem Michael addition/cyclization is developed for the synthesis of benzo4,5imidazo1,2-
a
pyridines from α-bromocinnamaldehyde. The RIM of the benzene ring at the C1-position makes them a new class of AIE molecules.
Four new Y-shaped D-π-A compounds
3a-3d
with an aryl acetylene moiety bearing two benzothiazole branches were concisely synthesized in two steps. Their photophysical properties in solution and powder ...states have been investigated and further confirmed
via
theoretical calculations. All compounds
3a-3d
show strong solid-state fluorescence, aggregation induced emission and near-infrared fluorescence. And, as anticipated, the modulation of the substituent on the aryl acetylene unit can largely affect the charge density of molecules as well as their fluorescence properties. Noteworthily, compound
3b
with methoxy as an electron-donating group presents significant solvatochromism because of its obvious intramolecular charge transfer effect. In addition, compounds
3a-3d
in the aggregated state (H
2
O/THF, v/v, 9/1) can be developed as a near-infrared fluorescent probe for picric acid (PA). Their limits of detection have been found to be 3.1 × 10
−7
, 6.1 × 10
−8
, 3.3 × 10
−7
and 4.6 × 10
−7
M, respectively. Among them,
3b
is the best design. Based on the results of
1
H NMR, SEM, DLS, lifetime and DFT calculations, aggregation caused quenching and photoinduced electron transfer have been revealed to be responsible for the quenching mechanism of detecting PA. Importantly, probe
3b
has also been successfully used to detect PA not only in real water samples with interferences, but also on
3b
-coated Whatman filter paper strips.
Four new Y-shaped NIR fluorophores are rationally designed and concisely synthesized; of these,
3b
is developed as a practical fluorescent probe for PA.
Under optimized reaction conditions, by directly using the hemostatic drugs 4-aminomethylbenzoic acid (ABA) and tranexamic acid (TA) as separate comonomers of lactic acid (LA), a series of ...copolymers, P(LA-co-ABA) and P(LA-co-TA), respectively, with different molar feed ratios were designed and synthesized via melt polycondensation and used as biobased polymeric sustained-release hemostatic materials. Their structure, properties and morphology were systematically investigated by Fourier transform infrared spectrometer (FTIR), proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), X-ray diffraction (XRD), differential scanning calorimetery (DSC), thermogravimetric (TG), scanning electron microscopy (SEM), water contact angle and degradation tests. The degradation rate within 7 weeks can reach 77%. When the molar feed ratios of ABA and TA are 20% and 10%, respectively, the corresponding copolymers have relatively lower crystallinity and smaller water contact angle and exhibit the best coagulation performance. In addition, these powdery copolymers have good application convenience, can form a degradable protective membrane similar to a blood scab on the wound surface and continuously exert hemostatic effects to promote wound healing, as anticipated.A series of polymeric hemostatic materials are prepared in one-step, by using biobased lactic acid monomers and mature hemostatic drugs (4-aminomethylbenzoic acid or tranexamic acid) through direct melt polycondensation. These materials are powdery with rough and irregular surfaces, and the powder particle size is ~8–30 μm, which is beneficial to the application, immediate hemostasis and scab-bionic membrane forming. Moreover, after the degradation of these materials at 37 °C, more monomers will be released, resulting in a higher efficiency and long-term hemostatic function.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Owing to their much more accessible structural diversity and recognition mechanism, the fluorescent probes with small molecular scaffold are significant, and they have been broadly investigated in ...the cutting edge of materials and biological chemistry. Known as the facile synthesis, expedient structural modification, good molecular stability, admirable fluorescence properties, multiple binding sites and excellent environmental compatibility, the benzazole moieties are under growing attraction in fluorescent probes for efficient detection of different species, such as cations (H+, Al3+, Hg2+, Cu2+, etc.), anions (HSO3−, F−, OH−, CN−, etc.), biomolecules (thiols, amino acids, etc.) and explosives (picric acid and TNT, etc.). In this review, benzimidazole-, benzoxazole- and benzothiazole-based fluorescent probes that have been reported in the recent three years (2017–2019) are refined to elucidate the progress of benzazole-based probes by combining their design strategy, synthetic route, sensing mechanism and applications. We wish that it may afford valuable recommendation to the construction of intelligent and versatile fluorescent probes based on benzazole derivatives.
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•A review for fluorescent probes with respect to benzazole-based molecules in recent three years.•Combination of design, synthesis, sensing mode, fluorescence mechanism and applications is the line of each case.•Provide valuable suggestions on probe design and put forward outlook for the developing trend of molecular probes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
