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A novel oxime-based fluorescent chemosensor (E)-2-(4′-(7,8,13,14-tetrahydrodibenzo[a,i]phenanthridin-5-yl)-[1,1′-biphenyl]-4-yl)ethen-1-ol (PBO) has been developed for the fluorimetric detection of hypochlorite ion (OCl−). On account of the optical behavior of the sensor PBO, distinctive spectral alterations in the presence of OCl− were detected. Furthermore, an obvious fluorescent color change from cyan to blue was also observed. An explicit linear relationship was found between the fluorimetric ratio of PBO and the concentration of OCl−. The detection limit (LOD) of PBO was evaluated to be 8 nM. The optical response was caused by the nucleophilic attack of OCl− on the imine group of the PBO probe, which stimulates intramolecular charge transfer. NMR titration investigation verified the detection mechanism. The PBO probe causes a quick spectral response towards OCl−, within 10 seconds. Furthermore, the practical utility of PBO was investigated through test paper analysis. The detection of OCl− in various water samples was also explored. The fluorescence bio-imaging experiment indicates the potential ability of the sensor PBO to detect OCl− in live E. coli cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • Imidazole derived new chemosensor for selective detection of CN− ions. • Sensor BMA responds rapidly toward cyanide ions with a low LOD (7.87 nM). • The detection mechanism of BMA with CN− has been studied extensively. • The sensor BMA can detect cyanide ions in live cells and food samples. On account of the supreme toxicity of CN− ions in the physiological systems, it is essential to develop a sensitive chemosensor to detect cyanide ions. Herein, we designed a new 5-(3-(4,5-diphenyl-1H-imidazol-2-yl)-2-hydroxybenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (BMA) sensor, which exhibits tremendous colorimetric as well as fluorometric behaviour towards CN− ions. This could be due to the nucleophilic attack of CN− ions on the dione-vinyl site, which induces intramolecular charge transfer (ICT) capabilities. The cyanide recognition mechanism of BMA was verified by optical experiments such as UV–visible and fluorescence spectroscopy, NMR, and mass analysis. Moreover, the structural characterization was done by 1H NMR titration and HRMS analysis, and the molecular orbital interactions were studied by TDDFT calculations. The sensor BMA exhibited a rapid response towards CN− ions (10 sec) with low detection limit (7.87 nM), great pH stability in the physiologically applicable pH range (6–12) and had good sensitivity and selectivity towards CN− ions. Encouraged by these detection properties, we successfully used sensor BMA to determine CN− ions in real water and food samples. To validate the colorimetric behavior of the sensor BMA , test paper strip experiments were carried out in the laboratory. We also extensively studied the effect of the sensor in Escherichia coli (E.coli) bacterial cells. [ABSTRACT FROM AUTHOR]

A new colorimetric, fluorescent chemosensor 2-(benzo[ d ]thiazol-2-yl)-3-(3-(benzo[ d ]thiazol-2-yl)-4-hydroxyphenyl)acrylonitrile (DBTH) with a D-π-A framework has been developed for the detection of cyanide anion (CN−). DBTH can display a high degree of selectivity and sensitivity towards CN− relative to a wide variety of competing anions. DBTH undergoes a color change from colorless to brown after reaction with CN− because of a strong blue shift in the absorption peak at 353 nm. The interaction between blue-fluorescent DBTH and CN− results in a significant decrease in fluorescence. The nucleophilic addition of CN− is the cause of the optical response of DBTH to CN−. The hypothesized mechanism was supported by 1H NMR titrations, mass spectroscopy, and DFT calculations. The detection limit of the probe is (colorimetrically 8.4 nM and fluorometrically 8.9 nM), which is less than the threshold of 1.9 μM set by the World Health Organization (WHO) for CN− ions in an aqueous solution. DBTH coated test kits were developed for on-site detection of cyanide ion that have the added benefit of being solid-supported chemosensors. [Display omitted] • A new chemosensor (DBTH) for the highly selective and sensitive detection of CN− was developed. • The receptor shows distinct colorimetric and fluorescence "on-off "changes upon the addition of CN−. • The sensing mechanism between the receptor and CN− was given in clear detail. • DBTH had a detection limit of (Colorimetrically 8.4 nM and fluorometrically 8.9 nM) towards CN−. • DBTH- coated test strips were developed for quick detection of CN− ions on-site. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new 1,3 propane dithiol substituted naphthalimide based "turn-on" fluorescence sensor for detection of Hg2+ was developed. • TNA was also spiked to detect Hg2+ ion in various environmental water samples. • The present sensor probe was successfully utilized to detect Hg2+ ion in biological cell using fluorescence bio-imaging. • The obtained detection limit (LOD) for Hg2+ is found to be 3.3 nM. This work represents a napthalimide derived fluorescent sensor for the selective and sensitive detection of Hg2+ utilizing the thioacetal group as a sensing unit. The immense selectivity of 6-(4-(1,3-dithian-2-yl)phenyl)-2-(2-morpholinoethyl)-1H benzo[de]isoquinoline-1,3(2H)-dione (TNA) has been investigated in ACN: H 2 O (8:2) system and the rapid response towards Hg2+ was found to be 10 s. In detecting Hg2+, TNC exhibits a blue emission (λ max = 429 nm), and the limit of detection was evaluated to be 3.3 nM. The sensing mechanism describes that the Hg2+ induces colorless to blue fluorescence-enhancement at 429 nm originated from the de-thiolation of an aldehyde. This stimulates the ICT process of TNA which resulted in the enhancement in fluorescence. Moreover, the sensor ligand was effectively applied for imaging Hg2+ in E-coli live cells. [ABSTRACT FROM AUTHOR]

A new Intramolecular charge transfer (ICT) based fluorescent sensor for recognizing Th 4+ ions has been successfully designed and developed. Sensor probe of 2-methyl-4-(4-(7,8,13,14-tetrahydrodibenzo[a,i]phenanthridin-5-yl)phenyl)but-3-yn-2-ol (1a) and 5-(4-ethynylphenyl)-7,8,13,14-tetrahydrodibenzo[a,i]phenanthridine (1b) selectively determined Th 4+ ion with an instant color change from colorless to blue in CH 3 CN:H 2 O (9:1) solvent system. The detection limit (1a : 3.4 × 10−8 M and 1b: 1.4 × 10−8 M) for Th 4+ ion was below the U.S Environmental Protection Agency's (EPA) permissible level in drinking water. In addition, 1a was applied to quantify thorium ions in natural water samples. The present sensor probe could detect thorium ions in biological cells using fluorescence bio-imaging with different emission channels. The detailed sensing mechanisms of 1a and 1b for Th 4+ ion have been investigated from NMR titrations, FTIR, Electrospray ionization (ESI)-Mass, and theoretical calculation techniques. [Display omitted] • New hydroxy and ethynyl substituted phenanthridine-based "turn-on" fluorescence sensor for detection of thorium ions were developed • Probe 1a was also tested to detect thorium ion in environmental water samples • The present sensor probes were successfully applied to detect thorium ion in biological cell using fluorescence bio-imaging • Sensor probes 1a-b -based test paper strips were used to detect efficiently thorium ion in water under UV lamp at 365 nm • The low detection limit sensors of 1a-b for thorium ion are 34 nM and 14 nM respectively [ABSTRACT FROM AUTHOR]

Aggregation-induced emission (AIE) active 3-(3-(benzo[d]thiazol-2-yl)-2-hydroxyphenyl)-2-(4'-(diphenylamino)-[1,1′-biphenyl]-4-yl)acrylonitrile (BTPA) has been designed and synthesized herein, with the goal of detecting CN− ions at a low-level in semi–aqueous medium. The deliberate addition of the electron-deficient alkene BTPA increased its sensitivity and selectivity to CN− ions, with a better detection limit of 6.4 nM, unveiling the next-generation approach to creating sophisticated CN− ions selective chemosensors. The ESI-MS and NMR spectra analyses provided strong support for the structures of the chemosensors, while the UV–Vis, photoluminescence, and 1H-NMR titration experiments provided support for the sensing efficiencies. Subsequently, PVDF/BTPA electrospun nanofibers have been effectively produced as functional films. These nanofiber films exhibit outstanding mechanical strength, photo/thermal stability, and optical responsiveness to CN− ions, making them a potential choice for on-field emerging contaminant detection. [Display omitted] • A conjugation extended Triphenylamine functionalized benzothiazole based ratiometric probe for the CN− ion has been developed. • The sensor probe recognizes CN− ions with good selectivity and a LOD of 6.4 nM. • The sensor is capable of detecting CN-ions in realistic water, portable polymer film and food samples. • The BTPA exhibits excellent properties such as AIE property and solvatochromism. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel imidazole derived bithiophene benzothiazole based sensor for the detection of Al3+ ions was developed. • The sensor DIBT effectively detect Al3+ ions with low LOD (13.7 nM). • Sensor DIBT was employed for the practical application in pharmaceutical samples. • The sensor DIBT can track Al3+ ions in live cells. Owing to the extensive application of aluminium ions (Al3+) in numerous industrial platforms, it is vital to design a chemosensor for the selective detection of Al3+ ions. Hence, we have attempted to introduce new imidazole appended bithiophene benzothiazole-based fluorescent sensor 2-(5′-(4,5-diphenyl-1H-imidazol-2-yl)-[2,2-bithiophen]-5-yl)benzo[d]thiazole (DIBT) , for the fluorescence ratiometric recognition of Al3+ ions in an aqueous medium (acetonitrile/water 8:2 v/v). We employed Job's plot experiments to study the mode of complexation of the sensor DIBT with Al3+ ions. The ratio of binding stoichiometry of the DIBT + Al3+ complex was found to be 1:1. The mode of binding was further verified using the 1H NMR titration experiments and HRMS analysis. The detection limit of DIBT with Al3+ was found to be 13.7 nM. We performed DFT and TD-DFT calculations to get in-depth insights into the mechanical aspects. The chelation-enhanced fluorescence type sensor DIBT was analyzed for its practical application in real water and pharmaceutical samples. The sensor DIBT can effectively track Al3+ ions in live Escherichia coli (E-coli) bacterial cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • A phosphinine containing sensor for the ratiometric fluorescent detection of Hg2+ has been developed. • Paper kit-based recognition was established. • The sensing mechanism of Hg2+ was clearly explained by 1H NMR and HPLC titrations. • The sensor could be utilized to detect Hg2+ in living cells. Due to its great toxicity to the bio-aquatic environment, developing highly selective and sensitive probes for the detection of mercury ions in solutions as well as in living cells is a major problem. To detect Hg2+ ions in organic semi-aqueous solutions, we created a fluorescent probe called 4-(1, 3-dithian-2-yl)-1,1-diphenyl- λ 5-phosphinine-2,6-dicarbonitrile (DDPD) with optical behaviour. Through the Hg2+-promoted deprotection process of thioacetals, which was followed by considerable changes in fluorescence colour and spectral pattern, the probe DDPD selectively detected Hg2+ ions in a broad pH range with a detection limit of 56 nM. Specifically, DDPD can be used to qualitatively identify Hg2+ ions using test strips made of Whatman filter paper and also in HeLa cells it can identify Hg2+ ions and image them using fluorescent microscopy. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new piperazine-based phenanthridine sensor probe was synthesized and characterized. • The fluorescence revealed that 5a is a superior selective sensor towards Th4+ ion in the presence of other competitive metal cations. • The kinetic study realized the detection of Th4+ ions in 15 s. • The limit of detection value is as low as 2.76 nM for Th4+ ion. • Probe 5a has been investigated for test paper strips applications as well as Th4+ ion analysis in real water samples. A benzhydrylpiperazine-based phenanthridine (5a) moiety has been developed as a ratiometric fluorescence and colorimetric probe for the detection of Th4+ ion. After the addition of Th4+ ion, probe 5a was immediately color-altered from blue to yellow fluorescence with an emission maximum at 560 nm. Probe 5a showed superior selectivity and sensitivity towards Th4+ ions over the other competitive metal ions. This sensor probe exhibited a lower detection limit (2.76 nM). Then through the 1H NMR titration experiment, it was confirmed that the benzhydrylpiperazine moiety of 5a was chelated with Th4+ ion. However, probe 5a was utilized for the detection of Th4+ ion in real water samples and monazite sand. Most importantly, the application of this sensor probe 5a for the recognition of Th4+ ion in E. coli cells had been successful. [ABSTRACT FROM AUTHOR]

Biological toxicity and dangerous environmental pollution are inevitable when the level of Th4+ and Fe3+ exceeds the safety threshold. To address these problems, in this study, we report a dual-emission response chemosensor, HQCA , for rapid, sensitive, and selective detection of Th4+ and Fe3+ via colorimetric and fluorescence turn-on strategy. The absolute fluorescent "turn off" of HQCA , due to photoinduced electron transfer (PET), was immediately turned on with yellow fluorescence over the exposure to Th4+/Fe3+. The sensing capability of HQCA toward Th4+ and Fe3+ was studied in solution, and paper strips were fabricated with HQCA. Our results indicate excellent sensitivity and selectivity. Additionally, the value of emission intensity of HQCA had an excellent linear relationship with the concentration of Th4+/Fe3+, and the limit of detection (LOD) was found to be very low compared to reported methods and WHO norms. The interaction mechanism between HQCA and Th4+/Fe3+ was studied via Job's plot analysis, 1H NMR, Mass, and FT-IR analysis. Emission analysis of HQCA in the pH region 1–9 indicated that HQCA could successfully detect Th4+/Fe3+ in the pH region of 3–9. More importantly, the viability of HQCA to detect Th4+/Fe3+ ions were successfully tested in various water bodies and human serum albumin. [Display omitted] • A new and efficient 10-hydroxybenzo[h] quinoline-based (HQCA) colorimetric fluorescent sensor was designed and synthesized. • Calorimetric and fluorescent analysis revealed that HQCA showed high selectivity and sensitivity towards Th4+ and Fe3+ions. • The detection limit was found to be 2.1 nM and 3.3 nM for Th4+ and Fe3+, respectively. • HQCA was successfully fabricated into test papers and applied for the detection of Th4+ and Fe3+ ions. • Real-time analysis of Th4+/Fe3+ was executed in various water samples and human serum albumin. [ABSTRACT FROM AUTHOR]