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Recently, 4-(pyrrol-1-yl)pyridine has been found to act as a supramolecular chemodosimeter, sensing nitrite ions in an aqueous solution with naked eye detection and a low limit of detection of 0.330 ppm. This work explores the anion-sensing properties of related derivatives, 4-(2,5-dimethyl-pyrrol-1-yl)pyridine and 4-(2,4-dimethyl-pyrrol-1-yl)pyridine, and provides a comparison with the parent compound. These molecules are determined to be effective sensors for nitrite ions with limits of detection of 1.06 ppm and 1.05 ppm, respectively. The high sensitivity and selectivity to nitrite remain even in the presence of competing anions such as SO32−, NO32−, PO43−, SO42−, Cl−, F−, I−, Br−, AcO−, and CN−. Analogous to the 4-(pyrrol-1-yl)pyridine system, the sensing mechanism appears to be the result of changes in the supramolecular aggregate system upon the interaction of an anion; this is further explored through dynamic light scattering, the Tyndall effect, and NMR spectroscopy. The two methylated derivative systems reported herein, 4-(2,5-dimethyl-pyrrol-1-yl)pyridine and 4-(2,4-dimethyl-pyrrol-1-yl)pyridine, are shown to affect the size of the supramolecular system and provide further insight into the unique mechanism of action. [ABSTRACT FROM AUTHOR]

Different spectroscopic techniques and Density Functional Theory (DFT)/Time-Dependent Density Functional Theory (TDDFT) calculations have been employed to investigate the dual channel CN− detection behaviour of the developed chemo-dosimeter (AK3). The CN− with AK3 reaction triggered a colour change from pale yellow to colourless and enhanced fluorescence. UV–Vis, fluorescence, 1H & 13C NMR and mass techniques coupled with theoretical calculations (Mulliken charges, dihedral angles) revealed that the CN− sensing process mechanism involves deprotonation of the N–H group followed by nucleophilic addition reaction. Detailed TD-DFT calculations showed that the relaxation of excited electrons from LUMO and to two different ground states is responsible for the weak/moderate fluorescence of AK3. Nucleophilic addition of CN− to the C-atom of the CH = CH bridge terminated the π-conjugation between donor and acceptor regions, reduced the coplanarity, decreased the ICT transition and consequently enhanced the fluorescence of the probe. The practical utility of the probe was demonstrated by detecting cyanide in food materials and determining CN− in environmental water samples. [ABSTRACT FROM AUTHOR]

A new colorimetric and fluorescence turn‐on chemodosimeter for selective detection of GSH over Cys and Hcy with 34‐fold enhancement in emission intensity is reported. Probe 1 exhibited ultra‐sensitivity toward GSH with 0.125 nM detection limit and successfully displayed GSH detection in MCF‐7 live cells. The mechanism of sensing is established by density functional theoretical calculations. [ABSTRACT FROM AUTHOR]

Sensors play a critical role in the detection and monitoring of various substances present in our environment, providing us with valuable information about the world around us. Within the field of sensor development, one area that holds particular importance is the detection of small molecules. Small molecules encompass a wide range of organic or inorganic compounds with low molecular weight, typically below 900 Daltons including gases, volatile organic compounds, solvents, pesticides, drugs, biomarkers, toxins, and pollutants. The accurate and efficient detection of these small molecules has attracted significant interest from the scientific community due to its relevance in diverse fields such as environmental pollutants monitoring, medical diagnostics, industrial optimization, healthcare remedies, food safety, ecosystems, and aquatic and terrestrial life preservation. To meet the demand for precise and efficient monitoring of small molecules, this summary aims to provide an overview of recent advancements in sensing and quantification strategies for various organic small molecules including Hydrazine, Glucose, Morpholine, Ethanol amine, Nitrosamine, Oxygen, Nitro-aromatics, Phospholipids, Carbohydrates, Antibiotics, Pesticides, Drugs, Adenosine Triphosphate, Aromatic Amine, Glutathione, Hydrogen Peroxide, Acetone, Methyl Parathion, and Thiophenol. The focus is on understanding the receptor sensing mechanism, along with the electrical, optical, and electrochemical response. Additionally, the variations in UV–visible spectral properties of the ligands upon treatment with the receptor, fluorescence and absorption titration analysis for limit of detection (LOD) determination, and bioimaging analysis are discussed wherever applicable. It is anticipated that the information gathered from this literature survey will be helpful for the perusal of innovation regarding sensing strategies. [ABSTRACT FROM AUTHOR]

Recently, 4-(pyrrol-1-yl)pyridine has been found to act as a supramolecular chemodosimeter, sensing nitrite ions in an aqueous solution with naked eye detection and a low limit of detection of 0.330 ppm. This work explores the anion-sensing properties of related derivatives, 4-(2,5-dimethyl-pyrrol-1-yl)pyridine and 4-(2,4-dimethyl-pyrrol-1-yl)pyridine, and provides a comparison with the parent compound. These molecules are determined to be effective sensors for nitrite ions with limits of detection of 1.06 ppm and 1.05 ppm, respectively. The high sensitivity and selectivity to nitrite remain even in the presence of competing anions such as SO32−, NO32−, PO43−, SO42−, Cl−, F−, I−, Br−, AcO−, and CN−. Analogous to the 4-(pyrrol-1-yl)pyridine system, the sensing mechanism appears to be the result of changes in the supramolecular aggregate system upon the interaction of an anion; this is further explored through dynamic light scattering, the Tyndall effect, and NMR spectroscopy. The two methylated derivative systems reported herein, 4-(2,5-dimethyl-pyrrol-1-yl)pyridine and 4-(2,4-dimethyl-pyrrol-1-yl)pyridine, are shown to affect the size of the supramolecular system and provide further insight into the unique mechanism of action.

In this study, we prepared a 3D aerogel, PAN-C 3 N 4 , using polyacrylonitrile (PAN) and C 3 N 4 as raw materials through a hydrothermal method. Subsequently, a layer of COFs (FT) was grown on its surface. We modeled its structure and compared it with experimental PXRD patterns to obtain the possible final crystal structure. Afterward, through functionalization with butyne, we prepared a 3D aerogel composite, PAN-C 3 N 4 @FT@Butyne, which can be applied to the adsorption of both mercury(II) and elemental mercury vapor. In a short span of time (25 min), the maximum adsorption capacities of mercury(II) and elemental mercury vapor were found to be as high as 830.1 mg/g and 463 mg/g, respectively. Importantly, in the fixed-bed column study, the influence of flow rate and initial concentration of mercury(II) was evaluated through breakthrough curves, yielding an adsorption capacity of 25.48 mg/g. Meanwhile, the application of the fixed bed column for industrial wastewater treatment displayed exceptional adsorptive capabilities, reduced the concentration of mercury (II) from 10.0 mg/L to less than 1.76 μg/L, significantly below the permissible limit for drinking water (2 μg/L). In addition, PAN-C 3 N 4 @FT@Butyne can be utilized as a chemodosimeter to detect mercury(II) in solution within a mere 5 s, with a detection limit of 0.1 ppb. Furthermore, COFs (BT) were cultivated within the PAN-C 3 N 4 matrix as a control group, thereby demonstrating the widespread applicability of this strategy. [Display omitted] [ABSTRACT FROM AUTHOR]

An economical and green approach to the synthesis of naphthyl derivative for detection of l‐carnitine (3‐hydroxy‐4‐N‐trimethyl‐aminobutyrate) is practically important. We developed a naphthyl derivative as a probe showing 'turn‐on' response towards l‐carnitine selectively at pH 7.2 through ICT mechanism with a good limit of detection (LOD) of 0.126 μM. Using Job's plot for determining the binding stoichiometry, it was found that probe could form a more stable complex (1:1) with carnitine. The binding constant (K) between probe and carnitine was calculated as 8 × 107 M−1 using the Benesi–Hildebrand plot. The binding interaction of the probe with l‐carnitine was confirmed by nuclear magnetic resonance titrations, Fourier‐transform infrared spectroscopy, photo physical studies and density functional theory calculations. Meanwhile, the probe can be used to quantitatively detect carnitine in food samples. [ABSTRACT FROM AUTHOR]

A novel near-infrared (NIR) fluorescent probe (SWJT-9) was designed and synthesized for the detection of hypochlorite anion (ClO−) using a diaminomaleonitrile group as the recognition site. SWJT-9 had large Stokes shift (237 nm) and showed an excellent NIR fluorescence response to ClO− with the color change under the visible light. It showed a low detection limit (24.7 nM), high selectivity, and rapid detection (within 2 min) for ClO−. The new detection mechanism of SWJT-9 on ClO− was confirmed by 1H NMR, MS spectrum, and the density functional theory (DFT) calculations. In addition, the probe was successfully used to detect ClO− in HeLa cells. [ABSTRACT FROM AUTHOR]

Selective optical detection of highly toxic nerve agents and their mimics like diethyl cyanophosphate (DCNP) is of paramount importance for armed forces and first responders in order to decide the suitable medical countermeasures. The reported optical chemical sensors for DCNP suffered from poor selectivity due to their single point covalent interaction with analyte. To overcome this limitation, we herein, report a novel protocol utilizing a ditopic chemodosimeter which, in presence of tetrabutylammonium hydroxide (TBAOH), underwent dual interaction with reactive subunits of DCNP, viz., electrophilic phosphorus and cyanide, to induce unique changes in its fluorescence as well as colorimetric properties. Other interfering analytes could not trigger the similar optical response in the sensing probe due to the absence of electrophilic phosphorus and cyanide. A truth table was constructed to reveal that only DCNP but not other analytes could induce changes in both fluorescence as well as colorimetric properties of sensing probe. The linearity range of the proposed method was found to be 30–70 μM while chromogenic limit of detection (LOD) was calculated to be 99 nM which are comparable to the reported methods. Thus, use of indigenously available 2‐hydroxy‐1‐naphthaldehyde as sensing probe without requiring further chemical manipulation represented a significant improvement over the literature methods for DCNP sensing. [ABSTRACT FROM AUTHOR]

A new fluorescent (TMCD) probe has been developed for the detection of hypochlorous acid (HClO) with sensitive response toward HClO. The probe color changes from green to yellow during the addition of HClO following PET OFF mechanism. The chemodosimeter promoted a selective response to hypochlorous acid compared to other ROS and RNS with a detection limit at 89 nM. The binding mechanism of probe with guest molecules has been confirmed by NMR spectroscopy, Mass spectroscopy and DFT calculations. Research highlights: The sensor TMDC was synthesized by a simple method with high yield. The sensor colorimetric and fluorimetrically detection of HClO very easily in aqueous medium. The probe was easily recognized toxic ROS form of HClO compare than other ROS. The HClO detection of limit 89nM in aqueous medium was reported. [ABSTRACT FROM AUTHOR]

[Display omitted] • New three Re(I) tricarbonyl complexes were obtained and fully characterized. • Axial Br- ligand abstraction was confirmed by FT-IR and UV–vis in acetonitrile. • Complex 1 and 2 acts as turn-off and turn-on chemodosimeter, respectively, for Hg2+. • Reaction between Hg2+ with 1 or 2 leads to the formation of cationic derivatives. Three new rhenium phenanthroline tricarbonyl complexes were synthesized and fully characterized to examine changes in their photophysical properties and spectroscopic behavior in the presence of metal ions. To achieve this, the complexes were designed with modifications in both the phenanthroline and the axial ligand. The 4,7–dichloro–1,10–phenanthroline (Cl 2 phen) precursor was functionalized with two units of 1–aza–15–crown–5 (1A15C5) to obtain the complex [Re((A15C5) 2 phen)(CO) 3 Br] (1) with the aim to study the spectroscopic perturbations induced by the binding of the metal ions by this receptor. Interestingly, the rhenium complex 1 shows a particular behavior towards Hg(II) and Pb(II), as a result of the halide abstraction assisted by these metal ions. Additionally, in the presence of Cu(II) the interaction and coordination/binding with the macrocycle cavities is also presumed. The chemical reaction assisted by Hg(II) was confirmed by changes in the absorption, emission and FT–IR spectra of [Re(Cl 2 phen)(CO) 3 Br] (2) in presence of the heavy metal ion. These obtained profiles had similar patterns to the ones shown by the cationic complex [Re(Cl 2 phen)(CO) 3 (CH 3 CN)]PF 6 (3). As final confirmation, this last complex was also studied in the presence of metal ions and its spectra remained unaltered. [ABSTRACT FROM AUTHOR]

A molecular probe 3 containing phenyl substituted imidazolyl unit and diaminomaleonitrile (DAMN) moiety has been synthesized and characterized. Photophysical and electrochemical behavior probe 3 were studied in partial aqueous medium (ACN/H 2 O, 9.5:0.5 v/v). Probe 3 upon interaction with different class of ions showed sensitivity for Cu2+, ClO− and CN− ions with different response time and reaction rates due to variation in intramolecular charge transfer (ICT) process. Both Cu2+ and ClO− ions displayed enhanced emission due to hydrolysis of imine bond to form compound 2 in the medium whereas, with CN− fluorescence quenching was observed due to the deprotonation of –OH/–NH 2 functions. The kinetic and optical behavior of the probe suggested that interaction occurred in two steps with Cu2+ (complexation and hydrolysis; abs k 1 , 2 , 3 (Cu 2+) = 1.17, 0.74 and 0.06 s−1) and ClO− (hydrolysis and deprotonation; abs k 1 , 2 (ClO −) = 3.0 and 0.60 s−1) ions while CN− (abs k 1 , 2 (CN −) = 2.13 and 1.66 s−1) induces deprotonation in one step. The interaction of probe 3 with ClO− was relatively fast than with Cu2+/CN− ions. Job's plot analysis between probe 3 and ions revealed a 1:1 (Cu2+/ClO−) and 1:2 (CN−) ratio stoichiometry with good limit of detection (nM) and binding affinity (LOD, 17; K Cu 2+ = 3.23 × 106 M−1; LOD , 18.5; K ClO − = 5.23 × 105 M−1 and LOD , 23.2; K CN − = 5.50 × 109 M−2) respectively. Probe 3 displayed a naked–eye sensitive fluorescence response to detect tested ions on test paper strips and good recovery percentage of ions in real water sample analysis. [Display omitted] • An ICT based Probe 3 showed selectivity for Cu2+, ClO− and CN− ions in a partial aqueous medium. • The hydrolysis of imine bond of probe 3 in the presence of Cu2+ and ClO− ion rejuvenate aldehyde derivative. • DFT calculations were carried out to understand the behavior of probe 3 tested ions. • The analytical application of probe 3 with Cu2+, ClO− and CN− ions was demonstrated. [ABSTRACT FROM AUTHOR]

A chemodosimeter (1) based on dicyanovinyl with a strong intramolecular charge transfer (ICT) mechanism has been devised for the selective and sensitive detection of cyanide (CN−) in a tetrahydrofuran aqueous solution. In polar solvents, chemodosimeter 1 exhibits robust ICT-induced emission; however, in the solid state, its fluorescence weakens owing to the formation of molecular aggregates prompted by intermolecular π–π interactions. The colorimetric and ratiometric fluorescent changes observed in the chemodosimeter upon exposure to CN− result from the incorporation of CN− at the β-conjugated site of the dicyanovinyl moiety of chemodosimeter 1 , effectively hindering the ICT process. This alteration is supported by 1H NMR titration experiments and density functional theory calculations, which corroborate the cyanide-induced ICT on–off switching mechanism. The detection limit of chemodosimeter 1 (5.8 × 10−7 M) for CN− falls below the maximum allowable level of cyanide in drinking water (1.9 × 10−6 M), as established by the World Health Organization. Test strips utilizing chemodosimeter 1 offer a potential solution for swift and quantitative naked-eye detection of CN− in real-time scenarios. Moreover, chemodosimeter 1 was effectively employed for detecting cyanide in actual environmental water samples. [Display omitted] • A dicyanovinyl-based chemodosimeter was prepared for sensing CN−. • The sensor exhibits colorimetric and ratiometric fluorescence responses to CN−. • An ICT mechanism plays a key role in the sensing properties. [ABSTRACT FROM AUTHOR]

A realistically newly designed Cu2+ ion specific fluorescent chemodosimeter has been synthesized from α,α'-(E , E)-bis(benzylidene)cyclohexanone having a fused spiro-dihydropyran moiety characterized by 2D NMR and X-Ray Crystallographic study. It also demonstrates an irreversible, instant direct visualisation by unaided eye chemosensing property in aqueous buffer (pH 7.4) with a colour change from yellow to orange upto 0.3 × 10−6 M. • A new methodology have been developed for the synthesis of fused spiro-dihydropyran moiety, a fluorescent chemodosimeter from α,α'-(E,E)-bis(benzylidene)cyclohexanone. • Newly formed spiro-dihydropyran moiety has been characterized by 2D NMR and X-Ray Crystallographic study. • It shows 'turn on' fluorescent as well as instant visual sensitivity towards Cu2+ ion at ppm level in aqueous medium. • The oxidative electrocyclic ring opening of the Spiro probe generates 1,6-dicarbonyl compound proved by spectral study. [ABSTRACT FROM AUTHOR]

A novel biothiols-sensitive near-infrared (NIR) fluorescent probe RhDN based on a rhodamine skeleton was developed for early detection of drug-induced hepatotoxicity in living mice. RhDN can be used not only as a conventional large stokes shift fluorescent (FL) probe, but also as a kind of anti-Stokes frequency upconversion luminescence (FUCL) molecular probe, which represents a long wavelength excitation (808 nm) to short wavelength emission (760 nm), and response to Cys/Hcy/GSH with high sensitivity. Compared with traditional FL methods, the FUCL method exhibited a lower detection limit of Cys, Hcy, and GSH in 75.1 nM, 101.8 nM, and 84.9 nM, respectively. We exemplify RhDN for tracking endogenously biothiols distribution in living cells and further realize real-time in vivo bioimaging of biothiols activity in mice with dual-mode luminescence system. Moreover, RhDN has been successfully applied to visualize the detection of drug-induced hepatotoxicity in living mice. Overall, this report presents a unique approach to the development of large stokes shift NIR FUCL molecular probes for in vitro and in vivo biothiols biosensing. A large stokes shift FL and FUCL NIR probe RhDN was for the first time proposed and applied to visualize the detection of drug-induced hepatotoxicity in living mice. [Display omitted] • A facile biothiols-activated FUCL NIR probe RhDN was designed based on rhodamine skeleton. • RhDN represents an anti-Stokes emission at 760 nm with 808 nm excitation. • RhDN showed excellent sensitivity and low detection limit towards different biothiols. • RhDN was successfully used to evaluate drug induced hepatotoxicity in living mice. [ABSTRACT FROM AUTHOR]

[Display omitted] • A BODIPY based chemodosimeter for anion induced naked eye sensing of CO 2. • Mechanism of interaction between the deprotonated probe and CO 2 was studied by NMR titration. • The hydrogel film of the probe act as on site sensor for F−/CN− and CO 2. • F−/CN− anions induced quenching of emission owing to activation of Photo-induced Electron Transfer (PET). • The probe exhibits sensitivity towards CN− in 100% aqueous solution colorimetrically as well as fluorometrically. A BODIPY based chemodosimeter was designed and synthesized for detection of CO 2 gas in presence of F−/CN− ion. The changes were observed in the absorption spectra of the probe and corresponding colour changes were clearly distinguished by naked eye. The mechanism of sensing was studied by NMR titration which reveals that unlike previous reports our probe can detect as well as trap CO 2 through adduct formation. The sensing of CO 2 was also extended to solid state through immobilizing the probe into hydrogel matrix as well as onto silica. Both hydrogel composite and silica loaded with the probe exhibit colour changes upon exposure to CO 2. Also, the practical application of the probe was demonstrated through detection and estimation of dissolved CO 2 in carbonated beverages. Moreover, the probe can detect F− and CN− through two different mechanisms governed by the nucleophilicity of the anion. The type of interaction of the probe with F− and CN− were elucidated with absorption and NMR study. Both the F− and CN− ions induced quenching of emission of the probe owing to activation of PET (Photo-induced Electron Transfer). The anion induced change in fluorescence intensity of the probe was also demonstrated with theoretical study. Moreover, the practical applicability of the probe for CN− sensing was established through sensing of CN− in 100% aqueous solution. [ABSTRACT FROM AUTHOR]

A new receptor based on naphthalene diimide‐benzothiazole (NDI‐1) conjugate was designed and synthesized. The nucleophilic addition of cyanide ion to the NDI‐1 exhibited naked‐eye, a colorimetric change is an optical response. The addition of CN− ion to the NDI‐1 solution display change in red color to green. The UV‐Vis spectroscopy measurements establish for the sensing of CN− in chloroform solution. Moreover, NDI‐1 exhibited high sensitivity and selectivity towards CN− ions in the presence of the interfering other anions such as F−, Cl−, I−, Br−, HSO4−, H2PO4−, OAc−, ClO4− and HCO3−. The detecting mechanism was established by 1H NMR, DFT calculations and Job's plot analysis. Moreover, NDI‐1 exhibited very low limit of detection 85 nM. [ABSTRACT FROM AUTHOR]

We developed a new chromogenic and fluorescent "off–on" 1, 8-naphthalimide-derivated chemosensor 1 based on an F–-triggered desilylation reaction. It showed significant variations in UV/visible absorption (510 nm) and fluorescence emission wavelength (580 nm) for selective detection of fluorides in THF/H2O system (v/v, 50:50). Moreover, chemodosimeter 1-loaded test strips were successfully fabricated todetect fluorides efficiently. [ABSTRACT FROM AUTHOR]

A novel near-infrared (NIR) fluorescent probe (SWJT-9) was designed and synthesized for the detection of hypochlorite anion (ClO−) using a diaminomaleonitrile group as the recognition site. SWJT-9 had large Stokes shift (237 nm) and showed an excellent NIR fluorescence response to ClO− with the color change under the visible light. It showed a low detection limit (24.7 nM), high selectivity, and rapid detection (within 2 min) for ClO−. The new detection mechanism of SWJT-9 on ClO− was confirmed by 1H NMR, MS spectrum, and the density functional theory (DFT) calculations. In addition, the probe was successfully used to detect ClO− in HeLa cells.

Detecting and neutralizing Pd2+ ions are a significant challenge due to their cytotoxicity, even at low concentrations. To address this issue, various chemosensors have been designed for advanced detection systems, offering simplicity and the potential to differentiate signals from different analytes. Nonetheless, these chemosensors often suffer from limited emission response and complex synthesis procedures. As a result, the tracking and quantification of residual palladium in biological systems and environments remain challenging tasks, with only a few chemosensing probes available for commercial use. In this paper, a straightforward approach for the selective detection of Pd2+ ions is proposed, which involves the design, synthesis, and utilization of a propargylated naphthalene-derived probe (E)-N'-((2-(prop-2-yn-1-yloxy)naphthalen-1-yl)methylene)benzohydrazide (NHP). The NHP probe exhibits sensitive dual-channel colorimetry and fluorescence Pd2+ detection over other tested metal ions. The detection process is performed through a catalytic depropargylation reaction, followed by an excited state intramolecular proton transfer (ESIPT) process, the detection limit is as low as 11.58 × 10−7 M under mild conditions. Interestingly, the resultant chemodosimeter adduct (E)-N'-((2-hydroxynaphthalen-1-yl)methylene)benzohydrazide (NHH) was employed for the consecutive detection of CN− ions, exhibiting an impressive detection limit of 31.79 × 10−8 M. Validation of both detection processes was achieved through 1H nuclear magnetic resonance and density functional theory calculations. For real-time applications of the NHP and NHH probes, smartphone-assisted detection, and intracellular detection of Pd2+ and CN− ions within HeLa cells were studied. This research presents a novel naphthalene derivative for visually detecting environmentally toxic Pd2+ and CN− ions. The synthesized probe selectively binds to Pd2+, forming a chemodosimeter. It successfully detects CN− ions through colorimetry and fluorimetry, offering a low detection limit and quick response. Notably, it's the first naphthalene-based small molecule to serve as a dual probe for toxic analytes - palladium and cyanide. Moreover, it effectively detects Pd2+ and CN− intracellularly in cancer cells. [Display omitted] • Probe NHP selectively detects Pd2+ and forms chemodosimeter adduct NHH , showing a specific turn-on response to CN- ions. • The "off-on-off" ESIPT process led to the dual-channel detection of Pd2+ and CN− in an ethanol-H 2 O solution. • Consecutive detection, first of Pd2+ and then of CN-, showed naked-eye visibility, rapid response, and a low detection limit. • The study explored both on-site smartphone-based detection and intracellular detection of Pd2+ and CN- within HeLa cells. [ABSTRACT FROM AUTHOR]

• A fluoranthene-based colorimetric and ratiometric fluorescent chemodosimeter (FP) was designed and synthesized for the specific and sensitive detection of hydrazine over other competitive analytes. • The limit of detection of FP was found to be in the micromolar range (4.27 µM). • This chemodosimeter was able to detect hydrazine in the solution phase as well as in the vapor phase. • Theoretical calculations were used to investigate the sensing process. A new and simple fluoranthene-phthalimide conjugate (FP) was synthesized, and employed as a highly efficient hydrazine chemodosimeter in organo-aqueous solution. Based on the Ing-Manske reaction, the chemodosimeter FP showed a fast colorimetric and ratiometric fluorescent response for hydrazine with high sensitivity and selectivity over other competing analytes. The chemodosimeters detection limit for N 2 H 4 was estimated to be 4.27 µM. Theoretical calculations were also executed to validate the experimental findings. Furthermore, the test strips and cotton swab made from the chemodosimeter FP are capable of enabling the quick and easy detection of N 2 H 4 solution and vapour, respectively. [Display omitted] [ABSTRACT FROM AUTHOR]

A novel two-site chemodosimeter (SWJT-4) based on fluorescein skeleton to detect diethyl chlorophosphate (DCP) was designed and synthesized. It is a turn-on fluorescent probe for DCP with good selectivity and obvious color change in aqueous solution. Interestingly, the two oxime groups of SWJT-4 as dual response sites initiated different reactions with DCP to form a cyano group and an isoxazole ring, respectively. The corresponding mechanism was confirmed by 1H NMR, MS and DFT calculation. Moreover, SWJT-4 could be used as a fluorescent test paper to detect DCP vapor.

Simple and easy to engineer metal-sensing molecules that are capable of differentiating metal ions and producing metal-specific signals are highly desirable. Metal ions affect the thermal stability of proteins by increasing or decreasing their resistance to unfolding. This work illustrates a new strategy for designing bivalent fluorescent fusion proteins capable of differentiating metal ions in solution through their distinct effects on a protein's thermal stability. A new dual purpose metal sensor was developed consisting of biotin protein ligase (BirA) from B. pseudomallei (Bp) fused to green fluorescent protein (GFP). When coupled with differential scanning fluorimetry of GFP-tagged proteins (DSF-GTP) for signal-transduction detection, Bp BirA-GFP yields distinct protein unfolding signatures with Zn(II) and Cu(II) ions in aqueous solutions. The limit of detection of the system is ∼1 μM for both metal species. The system can be used in a variety of high-throughput assay formats including for the screening of metal-binding proteins and chelators. Bp BirA-GFP has also the additional benefit of being useful in Cu(II) ion field-testing applications through simple visual observation of a temperature-dependent loss of fluorescence. Bp BirA-GFP is the first example of a protein-based dual purpose Cu(II) and Zn(II) ion sensor compatible with two different yet complementary signal-transduction detection systems. Image 1 • Burkholderia pseudomallei biotin protein ligase senses copper and zinc ions in water. • GFP-tagged biotin protein ligase differentiates between copper and zinc ions. • The assay format allows high-throughput screening of metal chelating agents. • A simple visual in-field water testing format was devised for copper ion detection. • Recommended maximum impurity concentrations of copper are easily detected in water. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new PL and ECL chemodosimeter based on a bifunctional (pba) 2 Ir(dcbpy) for Hcy determination was developed. • The bifunction lies in the aldehyde group, providing active site and together with dicarboxylic acid groups, increasing water solubility. • The reaction between (pba) 2 Ir(dcbpy) and Hcy was confirmed by mass spectrum. • (pba) 2 Ir(dcbpy) can highly discriminate Hcy from cysteine in neural buffer. A photoluminescent (PL) and electrochemiluminescent (ECL) chemodosimeter for homocysteine (Hcy) determination was developed based on a bifunctional cyclometalated iridium(III) complex (pba) 2 Ir(dcbpy). (pba) 2 Ir(dcbpy) was prepared by using 4′-(2-pyridyl)-benzaldehyde (pba) as main ligand and 2,2′-bipyridyl-4,4′-dicarboxylic acid (dcbpy) as ancillary ligand. The existence of aldehyde group on the main ligand and dicarboxylic acid groups on the ancillary ligand endows (pba) 2 Ir(dcbpy) good water solubility. Importantly, the aldehyde group on the main ligand also furnishes the chemodosimetric active site, which could react with Hcy highly in neutral buffer solution based on a unique cyclization reaction with aminoalkylthiol group to produce a binding adduct, enhancing both PL and ECL signal. The photophysical and ECL properties of (pba) 2 Ir(dcbpy) in the absence and presence of Hcy were investigated and the response mechanism of the luminescence enhancement was confirmed by mass spectrum. Both PL and ECL measurements exhibited good linear relationships to the Hcy with the detection of limit at micro-molar level. More significantly, (pba) 2 Ir(dcbpy) possessed a relatively high discriminating ability to differentiate Hcy from structurally related molecule (cysteine) under neutral buffer conditions. The PL and ECL chemodosimeter based on cyclometalated iridium(III) complex with specific active site is universal to the analysis of other targets, thus opening a new avenue for the application of cyclometalated iridium(III) complex in PL and ECL field. [ABSTRACT FROM AUTHOR]

[Display omitted] • AIE-active fluorescent probe was designed for detection of Hg2+. • The reaction-based sensor possesses fast response and excellent selectivity. • The probe in solid state exhibits good sensitivity for Hg2+ in aqueous solution. • LOD of the probe as solid optical sensor was 1 × 10−6 M as discerned by naked eye. • The mechanism of this chemosensor was carefully verified. A new AIE-based luminogen TPES , as a ratiometric fluorescence probe for mercury(II) was readily synthesized. The probe combined the advantages of the outstanding specificity of Hg2+-triggered deprotection reaction of thioketal and the brilliant emission of AIEgens in aggregated state. Once encountered aqueous Hg2+, fluorescent color of TPES in THF-H 2 O (f w = 98%) altered from blue to green rapidly, while other metal cations gave no interference to the probe. And the mechanism of this chemosensor was carefully verified by 1H NMR analysis, FTIR and MS spectra. As expected, TPES exhibits excellent selectivity and sensitivity towards Hg2+ in the solid state. When using filter paper as the solid medium, the fabricated test strips could signify Hg2+ ions with the LOD as 1 × 10−5 M (Hg2+ in aqueous solution), accompanied with a distinct emitting altered from blue to green. Furthermore, by changing the medium from filter paper to silica gel plate, a more significant fluorescence alteration from blue to yellow was achieved, and the LOD was further optimized to 1 × 10−6 M as discerned by naked-eye. [ABSTRACT FROM AUTHOR]

• New chemo-dosimeter selectively and sensitively senses CN− via dual channel responses and Al(III) via CHEF effect. • Mechanism of CN− sensing involves deprotonation of phenolic -OH group followed by nucleophilic addition at imine C-atom. • 1H & 27Al NMR and mass spectral techniques reveal that Al(III) forms a 1:1 octahedral complex [Al(VDP1)(NO 3) 3 (H 2 O)]. • DFT and TD-DFT calculations confirm that weak fluorescence of the probe is due to CT character of the transition therein non-radiative decay dominates. • MTT assay indicates that the probe is less toxic to HeLa cells and could detect intracellular CN− and Al(III) ions by bioimaging. The selective and sensitive dual channel assay of CN− and fluorescence assay of Al(III) are reported using a simple organic probe (VDP1) in aqueous and non-aqueous media. The binding behaviours of these ionic analytes with VDP1 were studied using UV–Vis, fluorescence, (1H, 13C & 27Al) NMR and mass spectral techniques. VDP1 showed a highly selective change of colour and fluorescence enhancement with CN− ion immediately without interference from other anions. The experimental results revealed that the mechanism of CN− detection involves deprotonation of the phenolic -OH group followed by nucleophilic addition at the imine C-atom. The addition of Al(III) was found to enhance the fluorescence of VDP1 significantly through chelation-enhanced fluorescence effect (CHEF) by forming a 1:1 octahedral complex [Al(VDP1)(NO 3) 3 (H 2 O)]. The Density Functional Theory (DFT) and Time-dependent Density Functional Theory (TD-DFT) based theoretical calculations confirmed that the weak fluorescence of VDP1 is due to the charge transfer (CT) character of the transition in which non-radiative decay dominates. The theoretically computed optical properties matched well with that of experimental observations. The limits of detection (LOD) of these ionic analytes were also calculated and found to be much lower than the corresponding recommended limit set by the World Health Organization (WHO). MTT assay indicated that VDP1 is less toxic to HeLa cells and could detect intracellular CN− and Al(III) ions by bioimaging. [ABSTRACT FROM AUTHOR]

The use of a simple fluorescence microscopy-based image analysis method for quantitative gas detection experiments is presented. The method can help study many aspects of gas sensing where visualization and spatially resolved measurements are necessary. In this initial study, the basic parameters of gas sensing such as the sensitivity and responsivity of the microscopy-based image analysis method were compared to, and shown to be better than the more commonly used UV-Vis spectrophotometer-based measurements, for the specific case of detecting NO 2 gas using perylene dye doped PMMA (P-PMMA) thin films and individual nanofibers. A film thickness study was performed to identify that the responsivity and sensitivity of the films are controlled by NO 2 diffusion. • A fluorescence-microscopy based quantitative gas sensing method is presented. • Sensitivity and responsivity better than spectrophotometry-based measurements. • NO 2 detection response times scaled linearly with inverse film thickness. • Response times in films associated with NO 2 diffusion and adsorption kinetics. • First measurements from single nanofibers; 1–2 orders faster response than films. [ABSTRACT FROM AUTHOR]

Luminescent detection of heavy metals continues to be of growing importance considering their increasing inseparable roles in modern day lifestyle. To this end, we report a simple yet interesting thiourea derivative that results in detection of CuII in a turn‐on fashion via a chemodosimetric redox reaction leading to oxidative cyclization of the chemosensor molecule. Elaborate studies with regard to the sensing process have been performed along with the proposal of a plausible cyclization mechanism of the molecule. Furthermore, the probe optically detects HgII, yet another heavy metal of prime importance, discernable even to the naked eye. The occurrence of a coordination complex has been proved by UV/Visible spectroscopic experiments as well as ESI‐mass spectrometry. [ABSTRACT FROM AUTHOR]

Luminescent detection of heavy metals continues to be of growing importance considering their increasing inseparable roles in modern day lifestyle. To this end, we report a simple yet interesting thiourea derivative that results in detection of CuII in a turn‐on fashion via a chemodosimetric redox reaction leading to oxidative cyclization of the chemosensor molecule. Elaborate studies with regard to the sensing process have been performed along with the proposal of a plausible cyclization mechanism of the molecule. Furthermore, the probe optically detects HgII, yet another heavy metal of prime importance, discernable even to the naked eye. The occurrence of a coordination complex has been proved by UV/Visible spectroscopic experiments as well as ESI‐mass spectrometry. [ABSTRACT FROM AUTHOR]

We report here the application of a robust, selective primary amide moiety appended to a fluorescence signalling entity‐ anthracene, the sensing platform, 9‐AM with a view to fluorescent chemosensing of hazardous phosgene gas. The impressively fast (reaction time<1.5 min) detection of phosgene was achieved through the dehydration of the primary amide functionality to a nitrile group. A low detection limit of 5.56 nm ensures applicability of the probe for sensing of minute levels of phosgene well below prescribed safe limits. In addition, TLC sticks impregnated with the probe function as efficient gas phase phosgene sensors with real‐time applicability. [ABSTRACT FROM AUTHOR]

• A new chemodosimeter (DNPS) is introduced for selective detection of H 2 S from biogas and estimation in water. • DNPS can sense H 2 S colorimetrically at micromolar scale both in liquid and gaseous phase. • Reaction mechanism of DNPS with H 2 S was justified by detailed spectroscopic and theoretical analysis. • The probe DNPS can be implied as a potential sensor to the exposure of such harmful gas in our environment. A dansyl-naphthalimide conjugated sulfonamide (DNPS) is reported for the selective colorimetric detection of hydrogen sulfide from biogas at micromolar scale. The chemodosimetric changes of DNPS upon interaction with H 2 S in both liquid and gas phase have been well justified by spectroscopic and theoretical techniques. Potentiality of the probe DNPS can be implied to develop a sensor for quick detection to the exposure of such harmful gas and to protect our environment as well. [ABSTRACT FROM AUTHOR]

• An orange emitting sensor (R1) (>600 nm) with D-π-A architecture is synthesized. • The emission from R1 is retained in solid state, due to a careful molecular design. • R1 could detect CN− ion selectively without interference of other anions. • Sensing mechanism of CN− ion was well demonstrated. • Solid state sensing of CN− ion was achieved by preparing a test kit. Designing fluorescent molecular probes with longer wavelength emission (above 600 nm) features towards exclusive detection of CN− ion is highly challenging and rarely found in the field of fluorescent sensors. The contribution here reports a unique chemodosimetric design approach for selective sensing of CN− ion, in both solution and solid states. Towards this, we have utilized an orange emitting fluorescent probe (R1) (λ emission > 600 nm), where the fluorophore is threaded by a fluorene derivative. The bulky fluorine unit regulate the interaction between the fluoropore units to minimize aggregation caused quenching (ACQ). Upon introducing CN− ion, even in the presence of several other ions, intramolecular charge transfer (ICT) from the donor (phenothiazine) to the acceptor (cyanovinyl unit) was completely blocked in the covalently threaded fluorescent moiety and as a result the fluorescence was completely quenched. More importantly, the present system retained its fluorescence properties in the solid state and hence was utilized to detect CN− ion in the solid state through fluorescence quenching mechanism, which enabled the fabrication of a test kit for on-site analysis of CN− ion. DFT and TD-DFT calculations towards validating the experimental results were also performed in order to study the changes caused in the electronic properties of R1 before and after complexation with CN− ion. [ABSTRACT FROM AUTHOR]

Simple pyrene-based chemosensors 1 to 3, were synthesized from pyrene-1-carboxaldehyde and they were characterized using various spectroscopic techniques like UV–Vis, FT-IR, Mass, 1H NMR and 13C NMR. Among synthesized receptors, the receptor 1 shows high selectivity towards Hg2+ ions. Further, the high selectivity of receptor 1 towards Hg2+ ions in the presence of various other interfering metal ions like Ni2+, Zn2+, Mn2+, Co2+, Cu2+, Cr3+, Fe3+, Al3+, Ag+, Fe2+, Cd2+, Mg2+, Pb2+, Ca2+, Na+, K+ was confirmed by UV–Vis and fluorescence methods. The detection limit for Hg2+ ions was found to be 0.270 μM. The chemodosimetric irreversible hydrolysis of the receptor 1 in the presence of Hg2+ was studied by UV/Vis, fluorescence, FT-IR, LC-MS, 1H NMR and theoretical DFT study. Further, the real life applications of receptor 1 for the determination of Hg2+ ions were demonstrated by UV–Vis method. Unlabelled Image • New colorimetric/fluorescent chemodosimeter for Hg2+ ions was reported. • Receptor 1 showed sensitive response towards Hg2+ ions at μM detection limit. • Receptor 1 has the advantage to be a dual channel chemosensor. • The hydrolysis of imine by Hg2+ ions was confirmed by various spectroscopic methods. • The receptor 1 could be used for real-life application. [ABSTRACT FROM AUTHOR]

A NIR‐emitting fluorescent probe using phenothiazine and 1,3‐dimethylbarbituric acid (PMB) connected through methylene bridge was developed in a two‐step simple chemical reaction. The fluorescent probes were highly reactive towards various primary amines and the reaction was accompanied by the changes in the optical and fluorescent properties of the PMB characteristic to the amine and thereby can have the potential to be used as a sensor for amines. In addition to the ratiometric changes in the fluorescence intensity corresponding to the PMB before and after reaction with an amine, the emission spectral maximum is specific to the analyte. For, example 1,4‐diaminobenzene, 4‐methoxyaniline, aniline, hydrazine, ethylamine, ethylenediamine respectively shows the maximum at 532, 546, 555, 484, 497, and 488 nm and this unique feature originated due to the involvement of the analyte in the extended π‐conjugation with the probe. Sensor strips prepared using PMB coated filter paper were able to sense the volatile amine gases with shorter response time. Analysis of the strips using the CIELAB 1976 color coordinates provides different signals for hydrazine, aniline, propylamine, and ethylamine gases. The applicability of the sensor was further ascertained by monitoring the decomposition of skin used for leather processing and also proteins engineered with an amino‐functionalized unnatural amino acid. [ABSTRACT FROM AUTHOR]

Abstract Fluoride recognition and sensing via artificial receptors have attracted a great deal of attention since it plays an important and indispensable role in biological and environmental processes. Herein, a novel colorimetric and fluorescent chemodosimeter (3-triisopropylsilylflavone 1) based on 3-hydroxyflavone framework has been rationally designed and synthesized for selective recognition towards fluoride. As confirmed by UV–vis and fluorescence techniques, the fluorescent probe 1 exhibited a highly sensitive and selective as well as rapidly responsive (20 s) recognition towards fluoride with a large Stokes shift of 180 nm. The detection limit was deduced to be 0.68 μM, which is much lower than the limit concentration level in drinking water specified by USEPA. The distinctive sensing mechanism is attributed to fluoride-triggered desilylation reaction on the cleavage of Si O bonds, leading to the strong excited-state intramolecular proton transfer emission of 3-hydroxyflavone. In addition, test strips experiment based on the sensor demonstrated the excellently practical feasibility of 1 to sense fluoride even in ppm level. Moreover, the probe is cell permeable and can be capable of reliably detecting fluoride in living cells. Graphical abstract The first colorimetric and fluorescent chemodosimeter based on 3-hydroxyflavone framework has been rationally designed and synthesized for selective recognition towards fluoride in the field of flavone chemistry. Image 1 Highlights • A novel fluorescent chemodosimeter 1 for selective recognition towards fluoride has been designed and synthesized. • It presents the first chemodosimeter for selectiverecognition towards fluoride in the field of flavone chemistry. • The probe 1 exhibited a highly sensitive and selective as well as a rapidly responsive recognition towards fluoride. • The probe 1 is cell permeable and can be capable of reliably detecting fluoride in living cells. [ABSTRACT FROM AUTHOR]

Naked-eye colored chemo dosimeters based on symmetrical calix[4]azo dye conjugates A1–3 are synthesized and characterized. Calix[4]azo dye conjugates exhibit high selectivity and sensitivity in detection of Fe2+, Ni2+, Co2+, and Cr3+ ions, and the highest sensitivity is determined for Cu2+. For the rapid monitoring of Cu2+ ions a simple paper test strip system is developed. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A model chemodosimeter specific to Hydrazine was synthesized. • Re-assignment of Red shifted emission in deprotected HBT and protected HBT. • Ratiometry observed from HBT based chemodosimeters are reported to be due to ESIPT reappearance. • Spectroscopic analysis revealed anion of HBT is formed rather than returning of ESIPT. Abstract The -OH group protected 2-(hydroxyphenyl) benzothiazole (HBT) based ratiometric chemodosimeters have previously been reported to undergo regeneration of excited state intramolecular proton transfer (ESIPT) process upon deprotection. In the current work it is demonstrated for the first time that generation of anion of HBT leads to the optical changes in these types of chemodosimeters rather than regeneration of HBT by using a Hydrazine specific chemodosimeter based on substituted HBT. [ABSTRACT FROM AUTHOR]

Abstract A new promising rhodamine based colorimetric and fluorometric chemosensor, RDV has been designed and synthesized for specific detection of Hg2+ ion. It acts as highly selective "turn-on" fluorescent chemosensor for Hg2+ ion without interference from other competitive metal ions in aqueous acetonitrile medium. The drastic color change with addition of Hg2+, from colorless to pink, indicates RDV can acts as "naked-eye" indicator for Hg2+. The Hg2+ promoted selective hydrolysis of appended vinyl ether group in RDV followed by Hg2+ chelated complex formation with concomitant opening of spirolactam ring is the plausible sensing mechanism. The detailed absorption, fluorescence, 1H NMR, 13C NMR and mass spectrometry confirms the proposed sensing mechanism. The limit of detection (LOD) of Hg2+ by RDV is 136 nM indicating the high sensitivity towards Hg2+. The RDV shows consistent spectroscopic response in biological pH range 4–10. In addition to explore practical applicability of RDV , its paper strips have been made and used to detect Hg2+ in pure water solution up to 10 ppm level. Furthermore, the potential application of RDV for the sensing of Hg2+ in real water samples (tap water and drinking waters from different sources) were also monitored and demonstrated. Graphical Abstract A rhodamine appended vinyl ether probe (RDV) for selective Hg2+ recognition has been synthesized which gives "turn ON" emission response for Hg2+ ion in aqueous medium over other metal ions in a chemodosimetric approach. The LOD is 136 nM. RDV has been explored for paper strip application as well as Hg2+ analysis from real water samples. Unlabelled Image Highlights • A rhodamine appended vinyl ether probe (RDV) for selective Hg2+ recognition has been synthesized. • RDV gives "turn ON" emission response for Hg2+ ion in aqueous medium over other metal ions in a chemodosimetric approach. • The LOD value is as low as 136 nM. • RDV has been explored for paper strip application as well as Hg2+ analysis from real water samples. [ABSTRACT FROM AUTHOR]

In the present work the photophysical properties of a chemodosimeter, 2‐[4'‐(N,N'‐dimethylamino‐biphenyl)‐4‐methylene]‐iminophenol, 5 has been explored to recognize Cu2+ ion selectively through naked eye sensitive fluorescence "turn‐on" response. The observed fluorescence enhancement (∼58 fold) and rise in quantum yield (34%) with rapid response time is attributed to the hydrolysis of aldimine function in the presence of copper. The cell imaging studies showed that chemodosimeter, 5 is well‐suited to detect Cu2+ intracellularly. Additionally, the "Off–On" switching behavior of 5 has been utilized to mimic the function of a sequential logic circuit at molecular level. The photophysical properties of chemodosimeter exhibiting high slectivity for Cu2+ through fluorescence "turn‐on" response in solution and live cell. [ABSTRACT FROM AUTHOR]

The environmental pollution aspect, especially pollution of mercury ions (Hg2+), has become a worldwide dilemma as it poses a serious risk to the health of organisms and the environment. Even low concentrations of Hg2+ may be harmful to human well-being and give rise to a series of related diseases. Therefore, the methods for real-time, accurate, and low-cost detection of Hg2+ have high medical and practical value. Among the many analytical methods for detecting Hg2+, chemodosimeters stand out in terms of their characteristics of being extremely specific, low-cost, user-friendly, and in-situ real-time detection. In recent years, researchers have been working on the development of reactive organic small-molecule chemodosimeters for the determination of Hg2+ in the environment and living organisms. These chemodosimeters selectively detect Hg2+ through reactive recognition groups, so the selection of recognition groups is very important. Compared with other recognition groups, sulfur-containing recognition groups are often selected as recognition groups for Hg2+ detection because of their high selectivity, good reactivity, and excellent photophysical regulatory performance. Unfortunately, the reactive mercury ions organic small-molecule chemodosimeters containing sulfur recognition groups have not been summarized systematically. Therefore, the paper reviews the progress of research of reactive mercury ions organic small-molecule chemodosimeters containing sulfur recognition groups in the past decade, and introduces the response mechanism, performance, and practical application of these chemodosimeters in greater depth. We aim the present review to encourage researchers to design and synthesize more excellent organic small-molecule chemodosimeters for Hg2+ assays, contributing to their development and prevention of Hg2+ pollution. • The sulfur-containing recognition groups used for mercury ions detection are systematically reviewed. • This paper reviews the application of reactive fluorescent chemodosimeters containing sulfur recognition groups for mercury ions. • Specific challenges in the application of fluorescent chemodosimeters containing sulfur recognition groups are outlined. [ABSTRACT FROM AUTHOR]

Peroxynitrite (ONOO−), as a strong oxidative biomolecule, is considered a potential biomarker of drug-induced liver injury (DILI) that could disturb biochemistry processes and cause a great variety of liver diseases. However, it remains a significant challenge to discover quickly and track accurately ONOO− in vivo environments even if these active substances have aggravated liver damage. Herein, we developed a peroxynitrite-activable mitochondria-targeted phosphorescent chemodosimeter (Ru-Mit) for DILI monitoring, which was designed by covalently linking ruthenium(II) complex with the strong electron-withdrawing malononitrile moiety. In the presence of ONOO−, the chemodosimeter hard to be oxidized exhibited excellent turn-on phosphorescent response at 610 nm with a longer lifetime (∼ 300 ns). The sensing mechanism indicated the malononitrile group in Ru-Mit was removed via the hydrolysis of C=C bond, accompanied by the change of electronic structure and the enhancement of radiative transitions. Further, reliable signals are capable of not only imaging exogenous and endogenous ONOO− in mitochondria, but also visualizing APAP-induced and tolcapone-induced ONOO− generation in HepG2 cells by confocal luminescence imaging. This work might provide a new molecular platform to design and develop ONOO− probes, and it might be used as a practical tool to detect ONOO− for the pathogenesis research of DILI. [Display omitted] • A mitochondria-targeted phosphorescent chemodosimeter (Ru-Mit) is synthesized for detection of ONOO−. • Ru-Mit displays excellent turn-on phosphorescent response towards ONOO− at 610 nm with large Stokes shift (150 nm). • Ru-Mit exhibits fast response to ONOO− (within 60 s) and long phosphorescence lifetime (342 ns). • The phosphorescent chemodosimeter is applied for monitoring ONOO− during drug-induced liver injury in HepG2 cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • An AIE active chemodosimeter ACH was designed and synthesized. • The chemodosimeter exhibited high specificity and excellent sensitivity for Hg2+. • The novel probe showed mega Stokes shift (157 nm). • The detection limit of probe ACH was as low as 5.67 × 10−8 M for Hg2+. • It can be successfully applied to the detection of Hg2+ in real water samples. An aggregation-induced emission (AIE) active anthracene-based fluorescent chemodosimeter, anthracene-9-carbaldehyde hydrazone (ACH), was synthesized via a facile one-step reaction from anthracene-9-carbaldehyde (AC) and hydrazine monohydrate. The structure of probe ACH was completely characterized by a variety of methods, including MS, 1H NMR, 13C NMR, FT-IR, and elemental analysis. The probe ACH showed high specificity and excellent sensitivity for Hg2+ in MeOH-water (9/1, v/v) solution, which exhibited an obvious fluorescence "turn-on" change with a mega Stokes shift of 157 nm (λ Ex = 256 nm, λ Em = 413 nm) and a low detection limit of 5.67 × 10−8 M. Studies of the sensing mechanism indicated that the fluorescence "turn-on" response was presumably owing to the Hg2+-promoted hydrolysis reaction of ACH to provide the intensely fluorescent AC. It was worth noting that the reaction-based probe could be successfully used to detect the concentration of Hg2+ in real water samples and distinguish Hg2+ on the filter papers and TLC plates. We expect this work can stimulate the emergence of preferable fluorescent chemodosimeter for practical application. [ABSTRACT FROM AUTHOR]

Hypochlorite anion (ClO−) is a widely-used disinfectant and a microbicidal agent in the immune system. Accurate detection of ClO− in environmental and biological samples by simply prepared chemosensors/chemodosimeters is important. Herein, we report that a naphthalimide–sulfonylhydrazine conjugate with an imine (C=N) linker, prepared via simple condensation, acts as an effective fluorescent chemodosimeter for ClO−. The molecule exhibits a weak emission, but ClO−-selective cleavage of its C=N bond creates a strong green emission. Ab initio calculation showed that the emission enhancement by ClO− originates from the suppression of intramolecular electron transfer from the photoexcited naphthalimide through the C=N linker. This response enables selective and sensitive detection of ClO− at physiological pH range (7–9) and allows fluorometric ClO− imaging in the presence of cells.

Abstract A di-orthometallated triphenyl phosphite iridium complex Ir(dttpit)(phen)Cl (dttpitH 2 = tris (2, 4-di-tert-butylphenyl) phosphite, phen = phenanthroline), has been synthesied and characterized. The crystal structure was determined by X-ray crystallography. The photoluminescence spectrum of Ir(dttpit)(phen)Cl in CH 3 CN shows emission maximum at 528 nm. In 0.01 wt% PMMA films, its quantum yields and lifetime are 0.16 and 1.78 μs, respectively. The emission of Ir(dttpit)(phen)Cl at 528 exhibits 1393% enhance upon addition of Ag+ in CH 3 CN/H 2 0. The ratio of Ir(dttpit)(phen)Cl responding to Ag+ is 1:1, and the limit of detection is 0.13 μM. Ir(dttpit)(phen)Cl is a highly selective chemosensor for Ag+ over other metal ions. The interaction between the chlorine atom and Ag+ is responsible for the highly selective and sensitive phosphorescent senor for Ag+. Graphical abstract A di-orthometallated triphenyl phosphite iridium complex Ir(dttpit)(phen)Cl has been synthesized and fully characterized. The phosphorescence behaviour of Ir(dttpit)(phen)Cl toward different metal cations have also be studied which indicating a strong phosphorescence enhance by Ag+. The interaction ratio with Ag+ is 1:1. Unlabelled Image Highlights • An iridium complex with di-orthometallated triphenyl phosphite has been synthesized. • Ir(dttpit)(phen)Cl is a 'turn-on' phosphorescent chemodosimeter probe for Ag+. • The detection mechanism has been proved. [ABSTRACT FROM AUTHOR]

A simple, nontoxic, bio‐friendly, fluorescent chemodosimeter based on 2,4‐dinitrobenzene and thio‐rhodamine was designed and synthesized for the detection of toxic hypochlorite with high selectivity and sensitivity. First time, the oxidation property of the hypochlorite ion was applied on a hydrazide system (Ar−NH−N<). Practical utility of the sensor was proved through simple and fast visual detection of hypochlorite. Absorption and emission spectra exhibited the fast sensing capability of the sensor towards hypochlorite. The nontoxic, bio‐friendly properties of the sensor in living cells increased its real time practical applicability as it was successfully applied for in‐vitro detection of toxic hypochlorite in living cells. A simple, nontoxic, bio‐friendly, fluorescent chemodosimeter was developed for the detection of toxic hypochlorite. The oxidation property of the hypochlorite ion was applied on a hydrazide system. The sensor was practically applied for hypochlorite detection in living cells as well as fast visual sensing. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Two strategies were used to overcome aggregation caused quenching effect in the design of fluorescence chemodosimeters. • Salicylicaldehyde hydrazone derivatives were facilely prepared for the detection of pH with ratiometric fluorescence changes. • The sensors exhibited multiple-fluorescence emissions. • The emission wavelengths of the sensors in alkaline solution are far away from that in acidic solution. Abstract Fluorescent chemodosimeters based on organic molecules have been widely used in sensing applications. However, the study of ratiometric fluorescent organic chemodosimeters is not thoroughly. The major problem is their poor solubility in aqueous solutions, resulting in notorious aggregation caused quenching (ACQ) effect. In this work, two different strategies were used to overcome the ACQ effect and a series of ratiometric fluorescent pH chemodosimeters (1 – 3) were developed. In alkaline condition, 1 – 3 underwent deprotonation processes, producing 1a – 3a with negative charges to avoid the formation of aggregations. While in acidic condition, 1 – 3 underwent bimolecular condensation reactions, resulting in the formation of salicylaldehyde azine (SAA) derivatives (1b – 3b). SAA derivatives, a kind of classic aggregation-induced emission (AIE) luminogens which exhibit intense emission in their aggregated states, can effectively overcome the ACQ effect. This work provides a new approach for designing aqueous solution available ratiometric fluorescence chemodosimeters based on organic molecules. [ABSTRACT FROM AUTHOR]

Graphical abstract A new naphthalimide platform based indolium ion functionalized colorimetric as well as fluorometric chemodosimeter (L) has been synthesized which selectively sense CN− ion in aqueous media through nucleophilic addition of CN − in L with low detection limit. Highlights • Novel colorimetric chemodosimeter L is synthesised and characterised. • Visual detection of CN− ion is observed in aqueous media. • Nucleophilic addition of CN− ion in L makes the sensing process irreversible. • L exhibits high sensitivity and selectivity towards CN− ion. Abstract A naphthalimide platform based indolium ion functionalized colorimetric as well as fluorometric chemodosimeter (L) has been synthesized and characterized. This can selectively sense cyanide (CN−) in aqueous medium with a low limit of detection (approximately 0.5 μM), which is around four times lower than the value of 1.9 μM set by WHO. The UV–vis and PL studies have been carried out in 40% aqueous-acetonitrile medium which shows a significant change in the visible region allowing naked eye colorimetric detection of CN¯. The mass spectrometry and 1H NMR spectroscopy are used to characterize the corresponding cyanide adduct which has also been corroborated by time-dependent density functional theory (TD-DFT) during the establishment of the sensing mechanism. [ABSTRACT FROM AUTHOR]

A fluorescent chemodosimeter ( TPAII-2 ) for Hg 2+ was designed with four sulphur atoms in its trigger based on a multisulphite strategy and a control sensor ( TPAII-1 ) was synthesized according to the common design with the deprotection of dithiol. Compared to TPAII-1 , TPAII-2 displayed optimizing selectivity towards Hg 2+ over Ag + , one of the most interference species with strong sulphophile affinity. Further studies indicated the TPAII-2 still maintained the fast detection rate (<2 min) and high sensitivity (detection limited = 15 nM) in HEPES (contain 1% DMSO as cosolvent). As far as we known, sensors based on the deprotection of dithiol were still seldom reported in such solution because of their poor sensing actions in bulk of the aqueous. At last, TPAII-2 was utilized to monitor the Hg 2+ in Hela cells, which evidenced TPAII-2 could maintain the excellent sensing properties in more complex circumstance. More importantly, this recognizing method provided a powerful platform for sensing Hg 2+ in complex systems and highlighted the designing strategy combing the advantages from both coordination-based and reaction-based fluorescent sensors. [ABSTRACT FROM AUTHOR]

Based on Hg 2+ -promoted deprotection reaction of thioketal, a type of thioketal decorated conjugated polymer ( PTS ) with the feature of aggregation induced emission enhancement (AIEE) was successfully synthesized as fluorescent turn on probe for Hg 2+ . With the introduction of trace aqueous Hg 2+ , fluorescence of PTS in THF-H 2 O mixture (water fraction of 98%) exhibited significant enhancement. The response was very fast with good selectivity towards Hg 2+ due to the specific chemical reaction. Other common metal ions (Ag + , Cr 3+ , Al 3+ , Fe 3+ , Ca 2+ , Ni 2+ , Co 2+ , Pb 2+ , Cu 2+ , Zn 2+ , Mg 2+ , Fe 2+ , Mn 2+ , Cd 2+ , Ba 2+ , Li + , Na + and K + ) gave nearly no disturbance to the sensing process. Furthermore, the detection limit of Hg 2+ reached 2.3 × 10 −7  mol L −1 for this sensing system. [ABSTRACT FROM AUTHOR]