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A novel fluorescent chemosensor based on trimesoyl chloride–rhodamine (TR) was successfully synthesized. Rising chromogenic and fluorogenic spectral enhancements could be observed in trimesoyl chloride–rhodamine (TR) probes when Hg2+ and Fe3+ were added, respectively. TR has shown selectivity for Hg2+ and Fe3+ with high sensitivity due to metal ion complexation induced photophysical "turn-on" signaling responses. The detection limit towards Hg2+ was 2.46 × 10−8 M as determined by the 3σ method. At the same time, fluorogenic spectral enhancements were observed in TR, which exhibits a superior sensitive and selective recognition towards Fe3+ with 4.11 × 10−8 M of the detection limit. The test strips were used for colorimetric and simple detection towards Hg2+, which might finally enable the advancement of the Hg2+ sensor in the field of on-site detection. [ABSTRACT FROM AUTHOR]

In this study, we prepared an efficient chemosensor based on 2,3-diaminophenazine hydrochloride, and it exhibited good dissolvability in water; more importantly, it could act as an efficient chemodosimeter for the selective detection of CN− in pure water. Upon reacting with CN−, 2,3-diaminophenazine hydrochloride (Q1) displayed a remarkable visible and fluorescence response simultaneously with significant changes in both absorption and fluorescence spectra. Furthermore, the absorption and fluorescence detection limits of CN− were 1.95 × 10−7 M and 1.13 × 10−9 M, respectively. For practical applications, test strips based on this chemosensor could serve as convenient CN− detection tools. The chemosensor was also successfully applied to the detection of CN− in plant seeds and several natural water samples. [ABSTRACT FROM AUTHOR]

A water-soluble fluorescent chemosensor (D) based on 1, 8-naphthalimide derivative has been designed and synthesised as a new fluorescent sensor for successive detection of Fe3+and CN−. Fluorescence measurements show that chemosensorDhas excellent fluorescent-specific selectivity and high sensitivity for Fe3+over many other metal ions in pure water. Moreover, the complex ofDand Fe3+(D–Fe3+) displayed high sensitivity for CN−over many other anions in the same medium. Even more important, the recognition of the sensorDfor Fe3+andD–Fe3+complex for CN-could be used successfully in pure water. The test strips based onDandD–Fe3+exhibited good selectivity to Fe3+and CN,-respectively, we believe the test strips could serve as convenient and efficient Fe3+and CN−test kits. [ABSTRACT FROM AUTHOR]

As a novel macrocyclic host, pillar[5]arene can selectively recognise guest molecules in organic solvents. In this study, a fluorescent chemosensor composed of a functionalised-pillar[5]arene and Cu2+metal complex (PN–Cu), which shows good selectivity for CN−anions, has been designed and synthesised. Complexation between PN–Cu and anions has been probed by means of various fluorescence-based methods. PN–Cu, as a turn-on fluorescence chemosensor showed high selectivity towards CN−ions in comparison to other anions, and its detection limit for CN−was calculated as 9.03 × 10−7 M. The PN–Cu sensor can serve as a recyclable component in sensing materials. Moreover, the interaction between the singly functionalised pillar[5]arene and Cu2+has been probed through various tests. Based on the remarkable selectivity of the chemosensor PN–Cu, we propose that it might be used as a potential material for CN−recognition. Scheme 2. The proposed sensing mechanism of PN for copper(II) and cyanide in DMSO. [ABSTRACT FROM PUBLISHER]

Two kinds of fluorescent sensors (G 1 and G 2 ) for Fe 3+ bearing 1H -imidazo [4,5-b] phenazine derivatives have been designed and synthesized. G 1 can display ON-OFF-type fluorescence charged with high selectivity and sensitivity toward Fe 3+ in DMSO solutions. And other cations, including Hg 2+ , Ag + , Ca 2+ , Co 2+ , Ni 2+ , Cd 2+ , Pb 2+ , Zn 2+ , Cr 3+ , and Mg 2+ had no influence on the probing behavior. The detection limit of the sensor G 1 towards Fe 3+ is 2.860 × 10 −7 M. Once combined with Fe 3+ , G 1 displayed high specificity for H 2 PO 4 − . Furthermore, in the situ generated G 1 –Fe 3+ ensemble could recover the enhanced fluorescence upon the addition of H 2 PO 4 − resulting in an ON-OFF-ON sensing with a detection limit of 1.866 × 10 −7 M in the same medium. Notably, this sensor serves as a recyclable component in sensing materials. The reversibility and selectivity of G 1 /G 1 + Fe 3+ toward Fe 3+ /H 2 PO 4 − ions as a sequence dependent molecular keypad lock using the G 1 , Fe 3+ and H 2 PO 4 − as three different chemical inputs. In addition, the test strip based on G 1 was fabricated, which could act as a convenient and efficient Fe 3+ test kit. [ABSTRACT FROM AUTHOR]

In this work, a highly sensitive and selective mercury fluorescent sensor (E)-1-((5-(4-nitrophenyl)furan-2-yl)methylene) semicarbazone (BI) based on the 5-(4-nitrophenyl)-2-furan and semicarbazide groups was designed, prepared and utilized to monitor mercury ions in aqueous solution. Upon addition of mercury to BI in DMSO/H 2 O (8:2, v/v) HEPES buffer (pH = 7.2) solution, an observable decrease of fluorescent to dim red change occurs that can be monitored by using fluorescence spectroscopy at room temperature. Concomitantly, a remarkably reducing in the emission maximum of BI takes place from 580 (a.u.) to 300 (a.u.). The observations indicate that association of the chemosensor with mercury ions leads to the supramolecular self-assembly breaking and the cooperation reaction occurrence, intra molecular charge density decreased in the chemosensor, the phenomenon likely responsible for the large decrease observed in emission spectra. And the detection limit of BI for the determination of mercury was estimated to be 2.084 × 10 −9 M. Notably, this sensor serves as a recyclable component in sensing materials. The experiment proved that this sensor can be repeated use above 10 times. Therefore, the chemosensor has good application prospect for recognizing and detecting Hg 2+ in the environment. [ABSTRACT FROM AUTHOR]

In this study, we developed a novel chemosensor (ATS) that contains the 5-(4-nitrophenyl)-2-furan group and α-naphthylamine for the dual-channel sensing of mercury ions. Under attack from mercury ions, the probe undergoes a blocked process; moreover, it broke the intramolecular charge transfer (ICT) state of the chemosensor, which can be confirmed by 1H NMR, IR and MS studies. We designed this probe to produce a significant change in the color and fluorescence intensity that can achieve naked eye recognition. The experimental results proved that the 5-(4-nitrophenyl)-2-furan group is a very good chromophore. In addition, the ICT state inhibited the fluorescence of naphthylamine. The fluorescent intensity changed significantly when naphthylamine was released. Moreover, high selectivity experiments revealed that the fluorescent sensor is specific to mercury ions even with interference by high concentrations of other metal ions. The test strips based on ATS were fabricated, which could act as a convenient and efficient mercury ion test kit. [ABSTRACT FROM AUTHOR]

A reversible dual-channel chemosensor ( W ) based on double Schiff-base for ultrasensitive fluorescence detection of Cu 2+ in DMSO solution has been designed and synthesized. Upon the addition of Cu 2+ , the chemosensor W showed visible color changes (from yellow to colorless) and the fluorescence was immediately quenched. The fluorescence spectrum detection limit for Cu 2+ was 4.87 nM, which is much better than most reported fluorescent sensors for Cu 2+ . Interestingly, the sensing behavior was found to be reversible with addition of EDTA, which indicated that W not only could act as a nice candidate for Cu 2+ and EDTA controlled “ON-OFF-ON” fluorescence switch, but was utilized as an ultrasensitive IMPLICATION logic gate at the molecular level. More importantly, ion test strips based on W were fabricated, which could act as convenient and efficient test kits to detect Cu 2+ for “in-the-field” measurement. [ABSTRACT FROM AUTHOR]

In this work, a new phenazine-based derivative ( L-1 ) which based on 2,3-diamino-phenazine and 5-(4-chlorphenyl)-2-furaldehyde was designed to act efficiently in a chemodosimeter approach for the rapid and selective detection of silver ion in aqueous solution over a wide pH range. The addition of Ag + to an aqueous solution of L-1 induced a change in the solution color from yellow to shallow orange and fluorescent quenching, indicating that L-1 could act as an excellent ON−OFF-type fluorescent chemosensor for Ag + . With a detection limit of 3.25 × 10 −7 M, the chemosensor shows great potential to monitor Ag + in environmental analysis systems. Furthermore, this sensor can serve as a recyclable component in sensing materials. These properties make L-1 act as an accurate Ag + controlled ON−OFF−ON fluorescence switch and implication (IMP) function logic gate. In addition, the actual usage of sensor L-1 was further demonstrated by test kits and silica gel plates. Notably, the stoichiometry of the complexes between the sensor and Ag + is indicative of a 2:1 ratio which was determined by a Job's plot yielded from fluorescence titrations. And the mode of interaction between Ag + ions and L-1 has been supported by 1 H NMR spectroscopy and mass spectrometry studies. [ABSTRACT FROM AUTHOR]

A novel fluorescent chemosensor based on trimesoyl chloride–rhodamine (TR) was successfully synthesized. Rising chromogenic and fluorogenic spectral enhancements could be observed in trimesoyl chloride–rhodamine (TR) probes when Hg2+ and Fe3+ were added, respectively. TR has shown selectivity for Hg2+ and Fe3+ with high sensitivity due to metal ion complexation induced photophysical "turn-on" signaling responses. The detection limit towards Hg2+ was 2.46 × 10−8 M as determined by the 3σ method. At the same time, fluorogenic spectral enhancements were observed in TR, which exhibits a superior sensitive and selective recognition towards Fe3+ with 4.11 × 10−8 M of the detection limit. The test strips were used for colorimetric and simple detection towards Hg2+, which might finally enable the advancement of the Hg2+ sensor in the field of on-site detection. [ABSTRACT FROM AUTHOR]

A turn-on fluorescent chemosensor ( H - 1 ) for cyanide anions based on dihydroxy phenazine was designed and synthesised. The sensor H - 1 exhibits high sensitivity and good selectivity for cyanide in pure water. The CN − response mechanism involves a hydrogen bonding and deprotonation process in the sensor, which induced prominent fluorescence enhancement. The detection limit of the sensor toward CN − is 5.65 × 10 −7 M, and other anions had nearly no influence on the probing behavior. In addition, test strips based on the sensor were fabricated, which also exhibit a good selectivity to CN − in water. Notably, this sensor was successfully applied to detect CN − in food samples, which proves a very simple and selective platform for on-site monitoring of CN − in agriculture samples. [ABSTRACT FROM AUTHOR]

A chemosensor (CS) was designed and synthesized by simple method. Dual-channel instant detection of CN − was achieved under acidic conditions. It showed an immediate visible color change from yellow to colorless and blue fluorescence appearance when CN − was added. Colorimetric and fluorometric methods showed the detection limits of CN − were 3.9×10 −8 and 3.1×10 −9 M, respectively. The mechanism of chemosensor reactions with CN − ion was examined using 1 H NMR spectroscopy, FTIR spectroscopy, and DFT calculations. Test strips, which served as convenient and efficient CN − test kits, were fabricated based on the sensor. [ABSTRACT FROM AUTHOR]

Herein, by rationally introducing multi-interactions sites, a new rhodamine derivative BT was successfully designed and constructed. The BT can further self-assemble into a stable supramolecular organogel BTG and exhibits strong pink-white aggregation-induced emission (AIE). Interestingly, the BTG exhibits selective and ultrasensitive sensing property for Cu2+. The limit of lowest detection (LOD) of BTG for Cu2+ is approximately 0.829 nM. By adding Cu2+ into the BTG , a no fluorescence Cu2+ coordinated metallogel BTG-Cu formed. Due to the competitive coordination of Hg2+, the BTG-Cu exhibits promising sensing properties for Hg2+, such as high selectivity and ultra-sensitivity, fluorescence turn-on response, instant response to Hg2+ (<2s), and the limit of lowest detection (LOD = 0.567 nM). In addition, the xerogel of BTG and BTG-Cu were able to remove Cu2+ and Hg2+ from diluted aqueous solution at an adsorption rate of 99.02% and 99.46%, respectively. The thin films based on BTG and BTG-Cu were prepared, which can act as not only a supramolecular fluorescent material but a simple and efficient tool for detecting Cu2+ and Hg2+, respectively. [Display omitted] • Novel supramolecular organogel BTG with AIE effect was constructed. • The rhodamine-based sensor BTG shows ultrasensitivity for Cu2+. • The metallogel BTG-Cu can carry out ultrasensitive detection of Hg2+. • The BTG and BTG-Cu can adsorb and separate Cu2+ and Hg2+ from aqueous solution with nice adsorption property. • The film based on BTG-Cu act as a smart fluorescent display material. [ABSTRACT FROM AUTHOR]