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Long-term continuous imaging of endogenous HClO burst is of great importance for the elucidation of various physiological or pathological processes. However, most of the currently reported HClO probes have failed to achieve this goal due to their insufficient photobleaching resistance under a laser source. Herein, a highly stable ratiometric probe, HFTC-HClO 1, which is capable of continuously monitoring endogenous HClO burst over a long period of time, has been judiciously developed. Briefly, the de novo development of HFTC-HClO 1 mainly involved three main steps: (1) novel coumarins (HFTC 1–5) were designed and synthesized; (2) the most stable scaffold, HFTC 3, was selected through dye screening and cell imaging validation; and (3) based on HFTC 3, three candidate HClO probes were constructed, and HFTC-HClO 1 was finally selected due to its superior sensing properties toward HClO. Furthermore, HFTC-HClO 1 can quantitatively measure HClO levels in various real samples with excellent recovery (>90.4%), and the use of HFTC-HClO 1-coated test strips for qualitative analysis of HClO in real samples was also achieved. In addition, the application of HFTC-HClO 1 for long-term continuous monitoring of intracellular HClO burst was successfully demonstrated. Significantly, HFTC-HClO 1 was able to visualize HClO generated in the rheumatoid arthritis mouse model.

Highly toxic phosgene, diethyl chlorophosphate (DCP) and volatile acyl chlorides endanger our life and public security. To achieve facile sensing and discrimination of multiple target analytes, herein, we presented a single fluorescent probe (BDP-CHD) for high-throughput screening of phosgene, DCP and volatile acyl chlorides. The probe underwent a covalent cascade reaction with phosgene to form boron dipyrromethene (BODIPY) with bright green fluorescence. By contrast, DCP, diphosgene and acyl chlorides can covalently assembled with the probe, giving rise to strong blue fluorescence. The probe has demonstrated high-throughput detection capability, high sensitivity, fast response (within 3 s) and parts per trillion (ppt) level detection limit. Furthermore, a portable platform based on BDP-CHDwas constructed, which has achieved high-throughput discrimination of 16 analytes through linear discriminant analysis (LDA). Moreover, a smartphone adaptable RGB recognition pattern was established for the quantitative detection of multi-analytes. Therefore, this portable fluorescence sensing platform can serve as a versatile tool for rapid and high-throughput detection of toxic phosgene, DCP and volatile acyl chlorides. The proposed “one for more” strategy simplifies multi-target discrimination procedures and holds great promise for various sensing applications.

An ER-targeted fluorescent probe was presented for the HOCl detection in cisplatin-stimulated cancer cells.

A fluorescent chemosensor has been developed for discriminative detection of phosgene and a nerve agent mimic diethyl chlorophosphate (DCP), which was comprised of an anthracene-carboxyimide fluorophore and o-phenylenediamine (OPD) reaction site. Upon phosphorylation of OPD, the chemosensor displays an obvious fluorescence turn-on response toward DPC at 588 nm with instant response and a low detection limit (88 nM). By contrast, the chemosensor exhibits a colorimetric and fluorescence enhancement response at 500 nm toward phosgene with fast response (<2 min), high selectivity, and a low detection limit (72 nM). Furthermore, chemosensor-loaded test membrane was fabricated for real-time, portable and efficient discriminative detection of trace amounts of gaseous phosgene and DCP vapor with different optical responses.

A high brightness red fluorescent probe (S-BODIPY) has been developed for the sensitive and specific imaging of HClO/ClO–in vitro and in vivo. This probe exhibits some distinctive features such as excellent resistance to photobleaching, a high fluorescence brightness, high selectivity, as well as a good biocompatibility. Upon oxidation of the thio-ether group into sulfoxide, the probe showed a noticeable ratiometric fluorescence response toward ClO–with fast response (within 30 s) and a low detection limit (59 nM). The probe demonstrated the successful imaging of exogenous and endogenous HClO/ClO–in living HeLa cells, zebrafish, and mice with high signal-to-noise ratios. S-BODIPYallows for the real-time monitoring the level of ClO–in living cells by ratiometric fluorescence imaging, opening up exciting prospects to develop red and even near-infrared BODIPYs with high brightness and good photostability for in vivo imaging.

In this review, we have summarized the recent progress of Michael addition-based fluorescent probes for SO2and its derivatives in the design strategies, sensing performances, detection mechanisms and applications.

A coumarin-based fluorescent probe was prepared for rapid and visual detection of benzoyl peroxide. The probe could quantitatively determine benzoyl peroxide with fast response (<6 min), high sensitivity, and low limit of detection (163 nM). The probe exhibited good response toward benzoyl peroxide with a significant color change from blue to yellow along with fluorescence color alteration from red to blue. The probe determined benzoyl peroxide in real food samples (wheat flour, noodle, and dumpling flour) with good recoveries (90–114%). Furthermore, the probe was prepared into a paper-based test kit to determine benzoyl peroxide (30–100 μM) in real food samples with noticeable color and fluorescence change.

In this work, we reported an anthracene carboxyimide-based chemosensor (AC-Phos) for colorimetric and ratiometric fluorescence detection of highly toxic phosgene, which displayed rapid response (<5 min) toward phosgene with a high selectivity and a low detection limit (2.3 nM). Furthermore, a facile testing membrane with a polystyrene immobilizing chemosensor has been fabricated for real-time visualizing of gaseous phosgene.

Sodium metabisulfite (Na2S2O5) is widely used as a bleaching agent and food preservative. However, excess of S2O52−can irritate and damage the human body. In this study, we report a colorimetric and ratiometric fluorescent probe for visual detection of S2O52−. The probe can quantitatively determine S2O52−with high specificity and sensitivity, fast response (<30 s) as well as a low detection limit (6.8 nM). A 1,4-Michael addition reaction was proposed for the sensing mechanism of this probe, which was confirmed by 1H NMR and HR-MS spectra. The probe has been successfully utilized to determine S2O52−in food with good recovery, from the remarkable colorimetric and ratiometric fluorescence changes. The probe was also employed to visualize S2O52−in live cells. Furthermore, the probe has been successfully prepared into a portable kit for real-time visual detection of S2O52−in food. Therefore, this probe has great potential application for the detection of S2O52−in food and living cells.

A colorimetric and ratiometric fluorescent probe was developed for the detection of sulfite in sugar. The probe underwent a Michael addition reaction with sulfite, which resulted in significant changes in fluorescence ratios. The probe displayed a fast response (within 30 s) and high selectivity towards sulfite over other anions and bio-thiols. The fluorescence intensity ratios were linearly related to the concentration of SO32−ranging from 0 to 15 μM, and the limit of detection was determined to be as low as 12 nM. The probe was employed to determine the concentration of sulfite in sugar with good recovery.

Der Transportmechanismus von mittels Platin‐Katalysator aktiviertem Sauerstoff wurde mit einem System aus Nanopartikeln‐Schichten (Sandwichstruktur) untersucht. Die Ergebnisse zeigen, dass die aktivierte Sauerstoffspezies über die Gasphase transportiert wird, und dass der bisher allgemein akzeptierte Oberflächentransport (Spillover) vernachlässigbar ist. Allerdings ist die Lebensdauer der aktivierten Sauerstoffspezies sehr begrenzt. Aus Versuchen mit räumlich getrennten Pt‐ und C‐Schichten wurde die Lebensdauer auf 65 ms abgeschätzt. Der Abbau der aktivierten Sauerstoffspezies erfolgt vermutlich über die Anlagerung an andere Gasmoleküle oder an Wände. Die Identifizierung des dominanten Transportmechanismus und Quantifizierung der katalytischen Wirkung könnte wertvolle Hinweise für die Optimierung des Designs von katalytisch beschichteten Dieselrußpartikelfiltern geben.

The intramolecular electrophilic or thermal cyclization of arylene ethynylene precursors recently became a powerful method for the synthesis of new polycyclic aromatic hydrocarbons (PAHs). In this work, we investigated in detail the synthesis and intramolecular cyclization reaction of a series of peri‐ethynylene naphthalene oligomers in which the ethynylene units are fixed in close proximity within the naphthalene framework. The high reactivity of these precursors led to simultaneous thermal cyclization reactions, even during their syntheses. Electrophilic cyclizations with iodine were also undertaken. Several new PAHs containing five‐membered rings, for example, indeno[2,1‐a]phenalene, acenaphtho[1,2‐a]pyrene, and benzo‐ or naphtho‐annulated fluoranthene derivatives, were synthesized and their structures were unambiguously determined by X‐ray crystallographic analysis. Plausible mechanisms were proposed and it was demonstrated that oligomers most probably underwent intramolecular domino cyclization via either radical or cationic intermediates. The photophysical and electrochemical properties of these new PAHs were investigated and some of them displayed amphoteric redox behavior, due to the existence of five‐membered rings.

Die katalytische Oxidation von Kohlenstoffpartikeln ist u. a. bei der Regenerierung von Dieselruß‐Partikelfiltern von Bedeutung. Besteht zwischen Katalysator und Kohlenstoffpartikeln kein direkter Kontakt, so ist ein Transportschritt der aktivierten Sauerstoffatome notwendig (Oxygen‐Spillover). Die Reichweite der aktivierten Sauerstoffatome an Nanopartikel‐Schichtsystemen wurde untersucht. Die Partikelschichten bestanden aus einer ca. 20 μm dicken Platin‐Katalysatorschicht und einer ca. 300 μm dicken Kohlenstoffschicht, die durch eine inerte SiO2‐Partikelschicht mit variabler Dicke getrennt waren. Bei moderaten Umsätzen (< 40 %), die noch ohne substantielle Änderungen der Struktur der C‐Partikelschicht ablaufen, wurde eine Reichweite von ca. 160 μm gefunden. Die Reichweite der oxidierenden Spezies kann einen Ausgangspunkt bei der geometrischen Gestaltung von effizienteren katalytisch imprägnierten Rußpartikelfiltern bilden.

Meat’s freshness is closely related to food safety and human health and has received increasing attention nowadays. To on-site visually screen meat freshness in a fast and non-destructive manner, we rationally constructed a series of fluorescent probes (JDCN, JDNS, and JDPY) with distinct electron-withdrawing substitution groups based on julolidine-fused coumarin. These probes underwent an aza-Michael addition followed by an elimination reaction with cadaverine to generate a colorimetric and ratiometric fluorescence response, and their sensing performance was rationally enhanced by improving the electron-withdrawing strength of substitution groups. Particularly, JDCNwith a dicyanovinyl group as the reaction site exhibited outstanding sensing performance including rapid response (∼60 s), high selectivity, and low detection limit (14 nM). Furthermore, JDCNwas fabricated into test kits to detect cadaverine vapor with a high-contrast fluorescence change from red to green. Based on two-color visualization of cadaverine vapor, on-site non-contact and non-destructive monitoring of meat freshness was successfully achieved. The good sensing performance rendered JDCNtest kits a promising real-time fluorescence screening platform for rapid, non-destructive, and accurate evaluation of meat freshness.