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Donor-acceptor (D-A) type organic luminescent materials with intramolecular charge transfer (ICT) mechanism constitute a significant class of fluorescent probes for nerve agents sensing. However, blue-shifted emissions from nerve agents due to the protonation on donor moieties of the probes are still rarely studied and reported so far. Herein, by incorporation of high luminescence and photostability open-shell organic radicals with proton-responsive characteristics, for the first time, we report two D-A type radical-based probes, which enable high sensitivity, selectivity and good reusability nerve agents simulant (diethyl chlorophosphite, DCP) vapor detection via an uncommon blue-shift emission response. Specifically, the sensing mechanism is ultimately deciphered to be the DCP induced protonation of the donor of the radicals, whereas present fully reversal D-A electronic structure models and the nature of the doublet excited states. This sensing system offers new insights into the rational design and utility of luminescent radicals for more broad applications. [Display omitted] • Two D-A type organic luminescent radical-based film probes were constructed. • Exposure of the probes to DCP vapors leads to rarely emission blue shift responses. • The film probes exhibited rapid response and low LODs for DCP vapor detection. • The blue-shifted mode is attributed to the reversal D-A electronic structure. [ABSTRACT FROM AUTHOR]

A kind of organic-inorganic hybrid silica nanoparticles loaded with 1,8-naphthalimide borate ester (NIB@SiO 2) was used to detect trace hydrogen peroxide (H 2 O 2) vapor via turn-off mechanism. The detailed studies showed that utilizing silica nanoparticles can improve the adsorption properties and hydrophilicity of the sensing film, accelerate the deboronation reaction between the sensing material and H 2 O 2, and then shorten the response time successively, which is always the disturbing challenge for this deboronation-type fluorescent probe to H 2 O 2 vapor. The fluorescence of NIB@SiO 2 film was quenched greatly under H 2 O 2 saturated vapor within 5 s at room temperature and limit of detection (LOD) was estimated to be 184 ppt, which are among the best reported results. Thus, this study provides an ultrafast and highly sensitive organic-inorganic hybrid fluorescent probe to H 2 O 2 vapor, moreover, a new design strategy for promising H 2 O 2 fluorescent probe is revealed. [Display omitted] • A new hybrid material (NIB@SiO 2) was successfully prepared with blue fluorescence. • The probe showed a rapid, intense fluorescence quenching to H 2 O 2 vapor. • The adsorption properties and hydrophilicity of silica nanoparticles are conducive to film detection. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new hybrid material (NIPy-SiO 2) was successfully prepared with blue fluorescence. • NIPy-SiO 2 was used as "turn-on" fluorescent film probe to nerve agent simulants. • The probe showed distinct fluorescence quenching behaviors upon exposure to acids. Here, 1,8-naphthalimide-pyridine functionalized hybrid SiO 2 nanoparticles (SiO 2 NPs) are successfully prepared and applied as the fluorescent film probe for Organophosphorus (OP)-based nerve agent (Sarin, Soman and Tabun) simulants. By using this novel fluorescent film probe, not only the highly selective fluorescence "turn-on" signals for nerve agent simulants are obtained, but also the bedeviling false-positive interferences mineral acids are discriminated exhaustively by their fluorescence "turn-off" response. Hereby, this study demonstrates a novel platform for multiform nerve agent simulants detection and provide an effective strategy for the identification between nerve agent simulants and acids. [ABSTRACT FROM AUTHOR]

• The new fluorescence material, DB-WCZ , served as a turn-off type fluorescent film probe to H 2 O 2 vapor with high sensitivity and selectivity. • The quenching rate of DB-WCZ films toward H 2 O 2 can play up to 62% in 120 sand the fluorescent detection limit of DB-WCZ can be as low as 2.2 ppb. • The sensing mechanism was studied in detail and proved to be attributed to the deboronation of DB-WCZ. Because of the increasing use in improvised explosives and serious influences on the public society, peroxide-based explosives are vital targets for detection. Herein, we reported two new fluorescent compounds, DB-WCZ and DB-W , served as turn-off type fluorescent film probes to H 2 O 2 (a typical substitute for TATP) vapor. Both of DB-WCZ and DB-W are fluorene-pyrene compounds linked two borate ester units. The deboronation was contributed to the fluorescence quenching during the H 2 O 2 detecting process. Compared with DB-W , DB-WCZ film shows higher selectivity and sensitivity to H 2 O 2 vapor. The quenching rate can play up to 62% in 120 s and the fluorescent detection limit of DB-WCZ can be as low as 2.2 ppb, which might be due to the pendent carbazole units to DB-WCZ to form the porous microstructures and benefit the diffusion of H 2 O 2 vapor. [ABSTRACT FROM AUTHOR]

[Display omitted] • The first oral-administration near-infrared fluorescence molecular (NS-V) for detection the variation of viscosity was established. • The probe NS-V was developed on the basis of naphthalene and pyridine benzyl chloride salt, and emitted at NIR region (710 nm). • The robust probe NS-V possesses a large Stokes shift (∼262 nm in MeCN) and high signal-to-noise ratio. • The new probe NS-V can elucidate the variations of mitochondrial viscosity in abnormal state cells. • The robust probe NS-V was realized in situ visualization the changes of viscosity in gastritis mice, for the first time. Gastritis is one of the most common digestive disorders and affecting millions of people worldwide. Recent investigations discovered that abnormal viscosity changes in organisms are associated with an increasing number of diseases that cannot be cured or managed. However, the relationship between gastritis and viscosity has not been explored so far due to lacking the suitable tools for in situ detecting the variations of viscosity in stomach. Herein, we developed a new oral-administration fluorescent probe (NS-V) for in situ elucidation of gastritis viscosity variations, for the first time. Based on the TICT mechanism, the probe employs naphthalene as the fluorescence platform, the rotatable single bond as the viscosity sensitive site, N, N -dimethyl as the strong electron donating moiety and the pyridine salt as the strong withdrawing group to enlarge the π-conjugated system to prolong the emission wavelength. Interestingly, NS-V revealed a good fluorescence response for viscosity at the NIR region from a silent "off" state to "on" and demonstrated high sensitivity, large Stokes shift (262 nm in MeCN), and high signal-to-noise ratio. In addition, NS-V could elucidate the altered mitochondrial viscosity in inflammatory cells. More importantly, utilizing these satisfactory features of NS-V , we discovered a significant increase in viscosity in the gastritis mice. Notably, with the assistance of the oral fluorescence molecule, in vivo and in situ visualizing for the first time revealed the positive correlation between viscosity and gastritis. This work provides an important basis for the diagnosis of gastritis and the robust probe developed in this work possesses a potential application in diagnosis of gastritis without any pain. [ABSTRACT FROM AUTHOR]

The detections of explosives and chemical warfare agents (CWAs) are always important for global security. In this study, a simple donor (D)- acceptor (A) type small organic fluorescent triazole-based molecule (T1) is reported. T1 is composed of a central 4 H -1, 2, 4-triazole (TAZ) "core" and three external triphenylamine (TPA) groups. Its spin-coating films can realize the multi-analyte fluorescent prober to detect DNT (2, 4-dinitrotoluene), hydrogen peroxide (H 2 O 2 , the substitute for triacetone triperoxide (TATP)) and diethylchlorophosphate (DCP, the substitute for Sarin) vapors. Additionally, the combination of the triple sensing mechanism in the different channels affords three distinct sets of output-signal responses, these three hazardous compounds could be identified rapidly with high sensitivity and selectivity: fluorescence turn-off response to DNT, fluorescence turn-on response to H 2 O 2 and fluorometric-colorimetric dual-channel response to DCP. T1 fluorescent probe is highly advantageous for concurrently monitoring various hazardous target substances and simultaneously possessing the desirable sensitivity and selectivity, excellent reusability. Hereby, this study provides a prototype method to build novel multifunctional fluorescent probes to explosives and CWAs. ga1 • A small organic molecule (T1) as multifunctional fluorescent probe to detect multiple hazardous analytes. • T1 probe shows rapid response, excellent reusability, high sensitivity and selectivity to DNT, TATP and Sarin substitute gas. • T1 films show fluorescence turn-off response to DNT vapor. • T1 films exhibit fluorescence turn-on response to H 2 O 2 vapor. • T1 films display colorimetric-fluorometric dual channel response to DCP vapor. [ABSTRACT FROM AUTHOR]

• A novel conjugated polymer (P1) as probe to detect Sarin substitute DCP. • P1 is used as a dual-channel probe to DCP solution and the LOD is as low as 2.3 nM. • P1 film presents rapid response, high sensitivity and selectivity to DCP vapour. • P1 filter paper strip is used to detect DCP vapour and the LOD is as low as 0.7 ppb. • P1 realizes the properties recovery by adding water in solution and in gas phase. A novel 4 H -1, 2, 4-triazole (TAZ)-based conjugated polymer (P1) is reported as highly efficient probe to Sarin substitute Diethylchlorophosphate (DCP) both in solution and in gas phase, which featured rapid response, high sensitivity and selectivity and good reusability. The chemosensor displays obvious fluorometric and colorimetric dual-channel responses toward DCP solution and the limit of detection (LOD) is as low as 2.3 nM. Upon the exposure to DCP vapour, P1 film shows an instantaneous fluorescent red-shifted response (from 440 nm to 500 nm), accompanying the emission colour changes from blue to green. Furthermore, its filter paper strip is prepared for in-situ and real-time practical detection of DCP vapour. Even more remarkably, semiquantitative fluorescence cards based on P1 filter paper strips are also developed to visually detect DCP vapour and the LOD is as low as 0.7 ppb. What should be noted is that this chemosensor could realize the fluorescence/colour recovery by adding water not only in solution but also in gas phase, which endows this chemosensor promising application prospect. [ABSTRACT FROM AUTHOR]