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Abstract A novel rhodamine-based Schiff base derivative was obtained via the simple condensation of substituted formyl-1H-pyrrole and rhodamine 6G hydrazone. Fluorescence resonance energy transfer enabled the subsequent use of the derivative as a naked-eye colorimetric and ratiometric fluorescent sensor for Cu2+ in semi-aqueous solution, and the existence of the morpholine group enabled the further application of the sensor in imaging Cu2+ in the lysosomes of HeLa cells. Graphical Abstract Unlabelled Image Highlights • A novel pyrrole-rhodamine hydrazone has been synthesised from the commercial intermediate of sunitib. • The hydrazone acts as a colorimetric and ratiometric fluorescent probe for Cu2+ in semi-aqueous solution. • The probe has been used for imaging of Cu2+ in the lysosomes of HeLa cells. [ABSTRACT FROM AUTHOR]

A novel ‘D-π-A’ sensor 1 has been designed and prepared via the condensation reaction of 3‑ethyl‑2‑methyl‑1,3‑benzothiazol‑3‑ium iodide and 5‑nitro‑ o ‑vanillin. Upon treatment with cyanide, sensor 1 exhibited a significant near-infrared (NIR) fluorescence quenching at 663 nm. The MS, IR, 1 H NMR and DFT methods confirmed that the response of 1 to cyanide is due to the nucleophilic addition reaction, which results in the inhibition of the Intramolecular Charge Transfer (ICT) process in the sensor. Furthermore, sensor 1 was used for the determination of CN − in HeLa cells. [ABSTRACT FROM AUTHOR]

A simple chemosensor, namely, N -((quinolin-8-yl)methylene)acetohydrazide ( 1 ) was synthesized and used as an off–on fluorescence sensor, which exhibits high selectivity toward Zn 2 + in aqueous media. The probe has large Stokes shift of > 200 nm, and its detection limit for Zn 2 + is 89.3 nM. The binding process was confirmed through UV–vis absorption analysis, fluorescence measurements, mass spectroscopy study, 1 H NMR spectra and density functional theory calculation. The crystal structures of Zn 2 + , Ni 2 + , and Cu 2 + complexes based on 1 were determined through X-ray crystallographic analysis. The fluorescent probe was then applied to monitor intracellular Zn 2 + in HeLa cells. [ABSTRACT FROM AUTHOR]

A coumarin-based sensor C1 , namely 3-acetoacetylcoumarin was designed, synthesized and applied for hydrazine detection. Hydrazinolysis of the chemosensor gives a fluorescent coumarin-pyrazole product C1 − N 2 H 4 [3-(3-methyl-1H-pyrazol-5-yl)coumarin], and thus resulting in a prominent fluorescence off-on response toward hydrazine under physiological conditions. The probe is highly selective toward hydrazine over cations, anions and other biologically/environmentally abundant analytes. The detection limit of the probe is 3.2 ppb. The sensing mechanism was supported by 1 H NMR, IR, MS and DFT calculation. The application of the fluorescent probe in monitoring intracellular hydrazine in glioma cell line U251 was also demonstrated. [ABSTRACT FROM AUTHOR]

Two bis(pyrrol-2-yl-methyleneamine) chemo-sensors, 1, 3- and 1, 4-bis[3,4-dimethyl-5-ethyloxy -carbonyl-pyrrol-2-yl-methyleneamine]benzene (H 2 L 1 and H 2 L 2 , respectively) have been synthesized and characterized, which exhibit high selectivity as off-on fluorescence sensors toward Zn 2 + in CH 3 CN/H 2 O (9:1, v /v) solution. The detection limits of both sensors are at the parts per million level. Moreover, the probes H 2 L 1 and H 2 L 2 could sense Zn 2 + by “naked eye” with a color change from colorless to yellow, and from yellow to dark yellow, respectively. To test the practical use of the probes, the determination of Zn 2 + in real water samples was also evaluated. [ABSTRACT FROM AUTHOR]

[Display omitted] • A europium (III) complex bearing 2-hydroxyl-1H-benzimidazole moiety has been developed as a novel probe toward phosgene. • The probe exhibited giant Stokes shift (248 nm), low detection limit (67 nM) and high selectivity for phosgene sensing in solution. • The probe 1 loaded paper test strips could respond to phosgene gas (0–2 ppm) within 2 min. Phosgene (carbonyl chloride, COCl 2) is a widely used colorless gas in organic synthesis. However, its high toxicity sets a severe potential damage of public safety. As the fluorescence method has the advantages of simple operation and real-time detection of phosgene, it is extremely important to develop a fluorescent phosgene probe for public health and safety. This study aimed to present a simple Eu3+ complex (1) with 2-hydroxyl-1 H -benzimidazole moiety as a novel phosgene probe. Probe 1 exhibited characteristic emission of Eu3+ in CH 3 CN solution, which was specifically quenched after encountering phosgene. The change in the solution color from light red to dark could be easily distinguished with the naked eye under a 365 nm ultraviolet lamp. Finally, the test paper with probe 1 was fabricated for effortless, selective, and visual detection of phosgene gas. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple developed fluorescent probe was synthesized for rapid detection of CN– in colorimetric and fluorometric signal channels. • The crystal structure of the probe is reported. • The probe works in DMSO/HEPES (3:7, v/v) solution with large fluorescent emission (595 nm) and large Stokes shifts (145 nm). • The probe has been successfully applied to the imaging of CN− in C6 cells. In this work, a novel probe R was synthesized via Knoevenagel reaction between 3 H -benzo[ f ]chromium-2-formaldehyde and ethyl cyanoacetate for selective detection of CN– in both colorimetric and fluorescent signal channels. The recognition of CN– was through the nucleophilic reaction of CN– to C = C of probe R , which destroys π-conjugation and blocks the ICT effect of the probe, resulting in colorimetric and fluorometric responses. Probe R showed great sensitivity toward CN–, with large fluorescent emission (595 nm) and low detection limit (0.70 μM). Moreover, probe R can detect exogenous CN– in living cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • A deep-red morpholine-functionalized fluorescent probe has been developed. • The crystal structure of the probe is reported. • The probe could monitor ClO− with low detection line (12 nM) in neat aqueous solution. • The probe work with wide pH rang of 1.0–12.0, and the process of quench completed within 10 s. • The probe has been successfully applied to the imaging of ClO− in the lysosomes of living cells and zebrafish. Hypochlorite plays a significant role in physiological processes, particularly regulation of lysosomal functions, and is involved in various diseases. Thus, it is crucial to develop highly sensitive and selective molecule tools to detect HClO in lysosomes. Herein, a novel 2 H -benzo[ h ]chromene-pyridine derivative (1) was synthesized through condensation reaction, which exhibited a notable deep-red emission at 640 nm in pure water. This deep-red emission was specifically quenched by adding ClO−. The response of probe 1 toward ClO− was rapid (within 10 s), sensitive (detection limit of 0.012 μM), and effective over a wide range of pH (1.0–12.0). Due to the existence of morpholine as the lysosome-targeting unit, the probe was successfully utilized to monitor lysosomal ClO−. Moreover, the probe 1 was also applied to detecting ClO− in zebrafish. [ABSTRACT FROM AUTHOR]

Abstract: Six complexes of rare earth nitrates (Ln=La, Sm, Eu, Gd, Tb, Dy) with a new amide type ligand, N-(naphthalen-2-yl)-N-phenyl-2-(quinolin-8-yloxy)acetamide (L) have been prepared and characterized by elemental analysis, conductivity measurements, IR and and 1H NMR spectra. Under excitation, Eu(III) and Sm(III) complexes exhibited strong red emissions. And the luminescence intensity of Sm(III) complex is higher than that of Eu(III) complex. Thus the Eu(III) and Sm(III) complexes are the potential light conversion agent. However, the Tb(III) and Dy(III) complexes cannot exhibit characteristic emissions of terbium and dysprosium ions, respectively. The results of phosphorescence spectrum show that the triplet-state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion. In addition, the luminescence of the Eu(III) complex is also relatively strong in highly diluted tetrahydrofuran solution (2×10−4 mol/L) compared with the powder. This is not only due to the solvate effects but also to the changes of the structure of the Eu(III) complex after being dissolved into the solvents. Furthermore, owing to the co-luminescence effect, the proper La(III) or Gd(III) doped Eu(III) complexes show stronger luminescence than the pure Eu(III) complex. [Copyright &y& Elsevier]

Abstract: Three new aryl amide type ligands, N-(phenyl)-2-(quinolin-8-yloxy)acetamide (L1), N-(benzyl)-2-(quinolin-8-yloxy)acetamide (L2) and N-(naphthalene-1-yl)-2-(quinolin-8-yloxy)acetamide (L3) were synthesized. With these ligands, three series of lanthanide(III) complexes were prepared: [Ln(L1)2(NO3)2]NO3, [Ln(L2)2(NO3)2(H2O)2]NO3·H2O and [Ln(L3)2(NO3)2(H2O)2]NO3·H2O (Ln=La, Sm, Eu, Gd). The complexes were characterized by the elemental analyses, molar conductivity, 1H NMR spectra, IR spectra and TG–DTA. The fluorescence properties of complexes in the solid state and the triplet state energies of the ligands were studied in detail, respectively. It was found that the Eu(III) complexes have bright red fluorescence in solid state. The energies of excited triplet state for the three ligands are 20325cm−1 (L3), 21053cm−1 (L2) and 22831cm−1 (L1), respectively. All the three ligands sensitize Eu(III) strongly and the order of the emission intensity for the Eu(III) complexes with the three ligands is L3 >L2 >L1. It can be explained by the relative energy gap between the lowest triplet energy level of the ligand (T) and 5D1 of Eu(III). This means that the triplet energy level of the ligand is the chief factor, which dominates Eu(III) complexes luminescence. [Copyright &y& Elsevier]

[Display omitted] • A benzo[ h ]chromenen-based acetylhydrazone probe 1 containing a toluene sulfonamide group is reported. • Probe 1 showed rapid response (less than 30 s), low detection limit (0.34 μM) and high selectivity for ClO− detection. • Probe 1 can specifically image endogenous and exogenous ClO− in the endoplasmic reticulum of HeLa cells and zebrafish. Hypochlorite (ClO−) is a ROS that plays a crucial role in the immune system in the body. As the largest organelle in the cell, the endoplasmic reticulum (ER) manages various life activities. Thus, a simple hydrazone-based probe was designed, which provided a fast turn-on fluorescent response toward ClO−. With a terminal p -toluenesulfonamide group as the endoplasmic reticulum (ER)-specific site, probe 1 was mainly accumulated at ER of living cells, and could be used for imaging endogenous and exogenous HClO in cells and zebrafishes. [ABSTRACT FROM AUTHOR]

Abstract A rhodamine hydrazone 1 bearing coumarin moiety was designed and prepared. Compound 1 exhibited high selectivity toward Co2+ and trivalent metal ions with fluorescence enhancement in CH 3 OH solution. However, 1 selectively responded to Al3+ in nearly pure H 2 O media and was further applied to monitor Al3+ in live cells. Moreover, 1 could also act as a colorimetric probe toward Cu2+ in either CH 3 OH or H 2 O solution. In addition, sensor 1 displayed aggregation-induced ratiometric emission (AIRE) activities in mixed H 2 O/CH 3 OH solution. Graphical Abstract Unlabelled Image Highlights • A rhodamine hydrazone sensor bearing coumarin moiety with aggregation induced ratiometric emission has been developed. • The sensor could detect Al3+ in H 2 O solution with fluorescence enhancement. • The sensor has been used for imaging of Al3+ in living cells. • The sensor could recognize Co2+ and trivalent metal ions based on different 'turn-on' emission. • The sensor is a colorimetric probe toward Cu2+ in either CH 3 OH or aqueous solution. [ABSTRACT FROM AUTHOR]

[Display omitted] • A morpholine-containing sensor for the ratiometric fluorescent detection of SO 2 has been developed. • The sensor could have dual-response for SO 2 and viscosity. • The sensor could be utilized to detect SO 2 and viscosity in the lysosomes of living C6 glioma cells. The changes in sulfur dioxide and viscosity of lysosomes are significant indicators in physiological processes and the cell microenvironment. This study aimed to synthesize a hemicyanine-based probe for simultaneous detection of SO 2 and viscosity. The probe could not only rationally detect sulfur dioxide in a semi-aqueous solution with high sensitivity (limit of detection = 0.78 μM) and fast response (within 30 s) but also monitor viscosity via fluorescence emission enhancement at 580 nm. Further, the dual-response probe was successfully used to image SO 2 and viscosity in the lysosomes of living cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel dual-excitation ratiometric fluorescent probe for the specific detection of ONOO– was designed and synthesized. • Probe 1 showed fast response toward ONOO– with high selectivity and sensitivity. • Probe 1 can specifically image endogenous and exogenous ONOO– in living cells and zebrafish. Peroxynitrite (ONOO−) is a highly reactive oxygen species that plays a critical role in many physiological and pathological processes of cell function. This study aimed to propose a ratiometric fluorescent probe BDHCA derived from coumarin for determining the ONOO− level. ONOO− could specifically induce oxidative cleavage of the conjugated C = C double bond in probe BDHCA , providing a fluorescent ratiometric output. The response of probe BDHCA to ONOO− was selective, fast, and highly sensitive, with a detection limit of 50.3 nM. Biological imaging experiments suggested that probe BDHCA could be used to image ONOO− in living RAW264.7 cells and zebrafish. [ABSTRACT FROM AUTHOR]

[Display omitted] • A quinoline-based sensor for the ratiometric detection of HSO 3 − in an almost pure aqueous solution has been developed. • The sensor could be utilized to detect endogenous and exogenous HSO 3 − in the lysosomes of living C6 glioma cells. • The sensor could detect HSO 3 − in real water samples with good application value. A lysosome-targeting ratiometric fluorescent probe was synthesized for detecting sulfite based on sulfite-triggered nucleophilic addition reaction. Due to the specific reaction, the fluorescence intensity ratio (I 530 / I 390) of the probe in an almost aqueous solution (0.5% DMSO) changed significantly after the addition of HSO 3 −, corresponding to the change in the fluorescence color of the solution from green to blue. The recognition was conducted using high-resolution mass spectrometry, proton nuclear magnetic resonance, and density functional theory calculations. The fluorescent probe could be utilized to quantitatively monitor HSO 3 − in lysosomes of living C6 glioma cells and real-water samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel developed fluorescent probe was synthesized for subsequen detection of Al3+and PPi. • The fluorescent sensing properties can be achieved in almost 100% aqueous medium. • The detection limits of the probe 1 for Al3+ and PPi were 35.7 and 76.0 nM, respectively. • Probe 1 was successfully applied to the detection of Al3+ and PPi in lysosomes of HeLa cells. A simple hydrazone probe (1) was designed and synthesized for the successive detection of Al3+ and pyrophosphate (PPi) in almost 100% buffer environment. The probe provided O 2 N donor set for chelation with Al3+, leading to a distinct fluorescence boost at 510 nm. The in-situ formed 1 -Al3+ complex detected PPi with an "on-off" behavior. The detection limits for Al3+ and PPi were 35.7 nM and 76 nM, respectively. Benefiting from the existence of morpholine as lysosome-targeting group, probe 1 was successfully applied to the detection of Al3+ and PPi in lysosomes. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) spectroscopy of single-cell suspensions obtained from fresh specimens of breast cancer tissue and normal breast tissue by mechanical enzymatic digestion was obtained and analysed, which is different from most Raman studies using breast cancer cell lines. Random forest classification was implemented to develop effective diagnostic algorithms for the classification of SERS of different typed cells. We first examined the SERS spectra of the primary breast cancer single cell and normal epithelial single cell obtained by flow sorting cytometry due to their biomarkers of CD326+/CD45−. Comparison analyses on their SERS spectra disclose that the nucleic acid and protein levels of the primary breast cancer single cell are higher than those of the normal epithelial single cell, while the lipids are at a relatively lower level. An important finding is that the cholesterol, palmitic acid, and sphingomyelin in the cancer cell profiles exhibit stronger than those of normal cells, while the glycans are at a relatively lower level. Furthermore, the standard deviation (SD) of the normal epithelial single cell is larger than that of the breast cancer cell, and the SD of the primary breast cancer single cell is more obvious than that of the normal epithelial cells. In addition, the prospective application of an algorithm to the dataset results in an accuracy of 78.2%, a precision of 75.5%, and a recall of 66.7%. The breast cancer diagnostic model laid a solid foundation for judgment of breast-conserving surgical margins and early diagnosis of breast cancer. Unlabelled Image • The cells were obtained from patient's tissue by mechanical enzymatic digestion. • RF was implemented to classify of the breast cancer and the normal single cell. • The SD of the normal epithelial cells is larger than that of the cancer cells. • The cholesterol, palmitic acid and sphingomyelin in the cancer exhibit stronger. • The nucleic acid, protein levels of the cancer cell are higher than the normal cell. [ABSTRACT FROM AUTHOR]

A morpholine-functionalized pyrrole-cyanine probe was synthesized via a simple condensation reaction in high yield. This probe exhibits high selectivity toward ClO− on fluorescence and UV–vis spectra in neat aqueous solution. The strong green emission of the probe solution was quenched and the yellow color faded immediately upon the addition of ClO−. The detection limit of the probe for ClO− was 0.165 μM. The mechanism of hypochlorite-induced C C breakage was supposed on the basis of EIS-MS, NMR, and density functional theory (DFT) calculation. Finally, the probe was utilized to image ClO− in lysosomes of living cells. Unlabelled Image • A morpholine functionalized pyrrole-cyanine probe has been developed. • The probe could detect ClO− in 100% aqueous solution on both fluorescence and UV–vis spectra. • The probe has been applied for imaging lysosomal ClO− in living cells. [ABSTRACT FROM AUTHOR]

An efficient and stable fluorescent sensor is described for the detection and imaging of thiols. It is making use of silicon quantum dots (SiQDs) which can be rapidly prepared. They were characterized by transmission electron microscopy, X-ray power diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometry. The SiQDs have an absorption maximum at 300 nm and displayed blue-green fluorescence with excitation/emission maxima at 410/480 nm. A mixture of SiQDs and 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) exhibits strong fluorescence emission which however is quenched within 30 s of incubation with thiols. This is assumed to be due to an inner filter effect caused by the reaction of DTNB and thiols. The following thiols were tested: cysteine, homocysteine, and glutathione. The sensor has a linear response in the 3–100 μM thiol concentration range, and the LODs are between 0.80 and 0.96 μM. The sensor displays low cytotoxicity and was applied to fluorescence imaging of MCF-7 cells and Hela cells where it demonstrated excellent biocompatibility. Unlabelled Image • A sensor based on silicon quantum dots was in response to thiols. • Response time of 30 s with excellent selectivity towards thiols was achieved. • The sensor was effective for thiols detection in fetal bovine serum samples. • The sensor was applied in intracellular thiols imaging in living cells. [ABSTRACT FROM AUTHOR]

A simple chemosensor, 6-(1H-pyrrol-2-yl)-5,6-dihydro-benzo[4,5]imidazo[1,2-c]quinazoline (1), was synthesized via simple nucleophilic addition reaction coupled with Schiff base condensation. The probe 1 is aggregation-induced emission-active and could be used as an on–off fluorescence sensor toward Cu2+ in H 2 O/CH 3 CN (99.5%, v/v) solution. Furthermore, the resultant Cu2+ complex selectively responded to pyrophosphate (PPi) among various anions based on fluorescent on–off signal. In addition, the probe could be used for detecting Cu2+ and PPi in HeLa cells. Image 1 • A quite simple pyrrole-quinazoline-based fluorescent probe for Cu2+ and pyrophosphate has been developed. • The crystal structures of the probe and its Cu2+ complex were reported. • The probe is an aggregation-induced emission enhancement active compound. • The probe has been used for imaging of Cu2+ and pyrophosphate in living cells. [ABSTRACT FROM AUTHOR]

An aggregation-induced emission (AIE)- and intramolecular charge transfer (ICT)-based probe 1 (7‑hydroxy‑3‑(3‑methyl‑isoxazol‑5‑yl)‑chromen‑2‑one) that is highly selective for N 2 H 4 has been synthesized, exhibiting a 'turn-on' response toward N 2 H 4 in CH 3 CN/H 2 O solution. The detection limit of the probe was 2.90 ppb, which was evidently lower than the threshold limit value (10 ppb) recommended by the Environmental Protection Agency. Notably, the sensor could be used for the detection of N 2 H 4 in living cells. Unlabelled Image • A simple coumarin-based fluorescent sensor for hydrazine in either solution or aggregation states has been developed. • The sensor is an aggregation induced emission (AIE) active compound. • The probe could act as a fluorescent turn-on sensor toward hydrazine. • The probe has been applied in monitoring hydrazine in living cell. [ABSTRACT FROM AUTHOR]

Abstract A simple asymmetric hydrazone 1 based on salicylaldehyde was designed and prepared, and exhibited an evident aggregation-induced emission (AIE) at a long wavelength of 570 nm in aqueous medium. Probe 1 can selectively sense Al3+ in CH 3 OH solution through the chelation-enhanced fluorescence mechanism and also recognize Cu2+ via fluorescence quenching in H 2 O solution through the Cu2+-induced assembly of aggregates. In addition, the probe can be applied for detecting Cu2+ in biological samples. Graphical Abstract Unlabelled Image Highlights • A simple Schiff base-based fluorescent sensor for Cu2+ in aggregation states has been developed. • The sensor could also detect Al3+ in CH 3 OH solution with fluorescence enhancement. • The sensor is an aggregation induced emission active compound with emission at a long wavelength of 570 nm. • The sensor has been used for imaging of Cu2+ in living cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • An indene-chalcone-based fluorescence probe with lysosome-targeting has been developed. • The crystal structure of the probe was reported. • The probe could monitor carboxylesterase (CEs) with a short response time (20 min), low detection limit (1.3 × 10−4 U/mL) and large stokes shift (155 nm). • The probe has been successfully applied to the imaging of endogenous CEs in the lysosomes of living cells and zebrafish. An indene-chalcone-based fluorescence probe 1 was synthesized and characterized. Under physiological conditions (containing 5% DMSO), probe 1 showed satisfactory stability with a low background signal and recognized carboxylesterases (CEs) based on the catalytic hydrolysis of ester groups, releasing a significant green fluorescence. Probe 1 presents several features including a short response time (within 20 min), low detection limit (1.3 × 10−4 U/mL) and large stokes shift (over 155 nm). Notably, commercial lysosomal dye co-staining experiments illustrated the lysosomal localization function of 1 , with the probe also being used for cell and zebrafish imaging of endogenous CEs. [ABSTRACT FROM AUTHOR]

[Display omitted] • A water-soluble merocyanine-based fluorescent probe has been developed. • The probe could monitor H 2 S via ratiometric fluorescent signal in neat aqueous solution. • The probe is sensitive toward H 2 S with a detection limit of 0.81 nM. • The probe has been successfully applied to imaging H 2 S in the lysosomes of zebrafish. Hydrogen sulfide (H 2 S) has been recently regarded as one of the most important gasotransmitters in the metabolic system, while abnormal H 2 S concentration is associated with various diseases. Although numerous fluorescent probes have been developed for the detection of cellular H 2 S, only a few of them can monitor lysosomal H 2 S with ratiometric fluorescent output. Here, we developed a water-soluble probe 1 toward H 2 S by introducing 2,4-dinitrophenyl ether into a novel merocyanine-based dye. As expected, H 2 S induced an obvious red-shift of the probe from 520 nm to 580 nm in neat aqueous solution, and this fluorescent ratiometric response is highly selective and sensitive (with the detection limit of 0.81 nM), rapid (within 10 s), and effective in a wide pH range (2.0–10.0). In particular, the probe was successfully applied for tracing H 2 S in the lysosomes of living cells and in zebrafish. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple Schiff-based sensor of far-red fluorescent AIRE for Zn2+ was synthesized. • The resultant Zn2+ complex showed good reversibility when adding PPi in an almost aqueous media. • The sensor could be utilized to detect exogenous Zn2+ and PPi in HeLa cells. A simple Schiff-base fluorescent chemosensor (1) was synthesized by the reaction of 3-amino-pyrazine-2-carbohydrazide and 7-diethylamino-3-formylcoumarin; the sensor 1 displayed a notable green emission at 524 nm in DMSO and an aggregation-induced ratiometric emission (AIRE) at 555 nm in an almost buffered aqueous media (0.5% DMSO content). The AIRE of 1 was quenched following binding to Zn2+ ions, while the fluorescence emission in the far-red region was evidently enhanced at 628 nm. Notably, the ratiometric signal output could be utilized to specifically distinguish Zn2+ among various metal ions. Moreover, the 1 -Zn2+ complex was effectively employed as a fluorescent ratiometric chemosensor for pyrophosphate (PPi) detection. The detection limit was 3.52 μM and 2.45 μM for Zn2+ and PPi, respectively. The binding mechanism was evaluated by 1H NMR, ESI-MS, single-crystal X-ray diffraction, TEM, time-resolved fluorescence spectrophotometry, and density functional theory studies. Overall, owing to its sensitive fluorescence behavior, cell imaging studies demonstrated that this sensor is capable of sensing Zn2+ and PPi in living cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The probe realized the relay detection of Cu2+ and H 2 S in an almost neat aqueous solution through fluorescence and UV–vis spectra. • The probe exhibits a high fluorescence quantum yield (ϕ = 0.48), a short response time (<30 s), and. • Low detection limits for Cu2+ (26 nM) and H 2 S (88.5 nM). • The probe has been applied for bioimaging of Cu2+ and H 2 S in lysosomes of living cells. A new morpholine functionalized coumarin-based fluorescent probe 1 was easily synthesized. The probe realized the sequentially detecting of Cu2+ and H 2 S in the HEPES buffer solution (20 mM, pH = 5.0). It made a turn-off fluorescence response to Cu2+ by using a complex formation with a 2:1 binding mode, and the resulting complex was able to detect H 2 S according to the displacement approach with a turn-on fluorescence response. The detecting limits of probe 1 for Cu2+ and 1 –Cu2+ system for H 2 S were calculated to be 26 nM and 88.5 nM, respectively. This "on-off-on" recognition process was demonstrated by ultraviolet–visible spectroscopy, fluorescence spectroscopy, using proton nuclear magnetic resonance studies, electrospray ionization mass spectroscopy, single crystal X-ray diffraction, and using density functional theory calculations. In addition, both cell imaging and co-staining experiments showed that the probe could be utilized to visually detect Cu2+ and H 2 S in lysosomes. [ABSTRACT FROM AUTHOR]

A quinoline-based hydrazone, namely, bis((quinolin-8-yl)methylene)carbonohydrazide (1), has been designed and synthesized, which could be used as a dual probe for selective recognition of Co2+ and Zn2+ by monitoring changes in absorption and fluorescence spectral pattern, respectively. The detection limits of 1 for these two ions are 0.21 and 0.66 μM, respectively. The complex formation between 1 and Co2+/Zn2+ is responsible for the detection process, as confirmed through several spectral methods and DFT calculations. The application of the as-synthesized sensor is demonstrated in Zn2+ imaging in living cells. Unlabelled Image • A bis-hydrazone sensor bearing quinoline moiety has been developed. • The sensor could detect Zn2+ in semi-aqueous solution based on turn-on fluorescent signal. • The sensor acts as a colorimetric probe toward Co2+. • The crystal structures of the probe and its Zn2+ complex are reported. • The sensor has been used for imaging of Zn2+ in living cells. [ABSTRACT FROM AUTHOR]