Addition Of CN Research Articles

Azobenzene–Hemicyanine Conjugated Polymeric Chemosensor for the Rapid and Selective Detection of Cyanide in Pure Aqueous Media

A water-soluble polymeric probe was designed and synthesized that can be used for the colorimetric selective detection of cyanide ions in pure aqueous media. In particular, P1, a water-soluble random terpolymer (P1) of N,N′-dimethylacrylamide, 2-((E)-4-((E)-(4-((2-(acryloyloxy)ethyl)(methyl)amino)phenyl)diazenyl)styryl)-1,3,3-trimethyl-3H-indol-1-ium (M1), and N-(4-benzoylphenyl)acrylamide was synthesized via traditional free-radical polymerization. Upon the addition of CN− ions to a P1 solution, a macroscopically detectable color change of the solution from brick red to light yellow took place, which was associated with a low limit of analyte detection (1.23 μM). Notably, P1 exhibited excellent selectivity toward CN− over other anions and biothiols, which may be present in the medium. Such highly selective colorimetric response to CN− by P1 originated from the nucleophilic attack of CN− anions onto the electron-deficient polarized CN bonds of P1's indolium moieties, resulting in the perturbation of the intramolecular charge transfer process occurring within the probe via destruction of the polymer's extended π-conjugation. P1 was also immobilized on a quartz slide by spin coating and then exposed to ultraviolet light. The resulting polymeric film displayed a rapid response to CN− consisting in a distinct color change, extending the scope of the usefulness of P1 as a cyanide-ion probe beyond the solution phase. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 124–131

Reaction of GaIIIClPc, SnIVCl2TPP and BIIIClSubPc with cyanide anions: reduction of macrocycles vs. formation of cyano-containing macrocyclic anions.

The reaction of GaIIIClPc, SnIVCl2TPP and BIIIClSubPc containing phthalocyanine (Pc), tetraphenylporphyrin (TPP) and subphthalocyanine (SubPc) macrocycles with cyanide in the presence of cryptand[2.2.2] under anaerobic conditions yields crystalline salts in which cyano anions substitute chloride anions at GaIII, SnIV or BIII, as well as reducing the macrocycles or adding one or two CN- to them. The reaction of GaIIICl(Pc2-) with CN- yields {crypt(K+)}{GaIIICN(Pc˙3-)}˙-·0.5C6H4Cl2 (1) in which the Pc2- macrocycle is reduced to Pc˙3-. Such reduction could probably occur through the addition of CN- to Pc2- forming {GaIII(CN)[Pc(CN)]3-}- which can decompose further interacting with an excess of CN-. As a result, Pc˙3- and cyanogene anions are formed. The interaction of SnIVCl2(TPP2-) with CN- is accompanied by the addition of CN- to the meso-carbon atom of porphyrin forming diamagnetic TPP(CN)3- macrocycles in {crypt(K+)}{SnIV(CN)2[TPP(CN)]3-}- (2). Salt 2 shows a strong NIR absorption band with the maximum at 854 nm whose intensity is comparable with that of the Soret band. The interaction of BIIICl(SubPc2-) with three equivalents of CN- is accompanied by the addition of two CN- to carbon atoms of SubPc2- closest to meso-nitrogen atoms forming {BIII(CN)[SubPc(CN)2]4-}2-. Most probably these dianions transfer electrons to C6H4Cl2 producing the {BIII(CN)[SubPc(CN)2]˙3-}˙- radical anions which form σ-bonded diamagnetic dianions in {crypt(K+)}2{BIII(CN)[SubPc(CN)2]}22-·3C6H4Cl2 (3). The remaining carbon atom closest to the meso-nitrogen atom is involved in this dimerization. According to the calculations, the energy of the C-CN bond is minimal for {GaIII(CN)[Pc(CN)]3-}- enabling further transformation of these anions to {GaIIICN(Pc˙3-)}˙- in 1, whereas cyano-containing anions in 2 and 3 with higher energy of this bond are stable towards the elimination of CN. Optical and magnetic properties of 1-3 together with their crystal and molecular structures are presented. The possible ways of the formation of 1-3 are discussed based on DFT calculations.

Phenanthroimidazole and dicyanovinyl-substituted triphenylamine for the selective detection of CN−: DFT calculations and practically applications

A novel CN− selective fluorescent turn-on sensor (TPMN) possessing triphenylamine and phenanthroimidazole as signaling units and dicyanovinyl unit for the binding site was designed and synthesized. TPMN exhibited a drastic change in its emission spectra with about 13-fold fluorescence enhancement when treated with CN−, while other tested anions could not arouse the fluorescence enhancement. The experimental and theoretical calculation results showed that this increase in fluorescence intensity of TPMN in presence of CN− is due to the large decrease in the ICT effect by the addition of CN− ion to β-carbon of the dicyanovinyl moiety. TPMN could selectively detect CN− with a detection limit of 0.23 μM among the common anions. The CN−-binding mode was well-characterized to be 1:1 by using Job’s plot with an association constant of 5.36 (logKa). Besides, the possible utilization ofTPMN was successively tested in water samples and test kits.

Synthesis and the Effect of Anions on the Spectroscopy and Electrochemistry of Mono(dimethyl sulfoxide)-Ligated Cobalt Corroles.

A new series of cobalt A3-triarylcorroles were synthesized and the compounds examined as to their electrochemical and spectroscopic properties in CH2Cl2 or dimethyl sulfoxide (DMSO) containing 10 different anions added to the solution in the form of tetrabutylammonium salts. The investigated anions were PF6-, BF4-, HSO4-, ClO4-, Br-, I-, Cl-, OAc-, F-, OTs-, and CN-, all but three of which were found to facilitate reduction of the cobalt corrole in dilute CH2Cl2 solutions, as determined by a combination of UV-vis spectroscopy and spectroelectrochemistry. The synthesized corroles are represented as (Ar)3CorCo(DMSO), where Ar is a meso-phenyl group containing one of 10 different electron-donating or -withdrawing substituents. The axial DMSO ligand was found to dissociate in dilute (10-5 M) CH2Cl2 solutions, but this was not the case at the higher electrochemical concentration of 10-3 M, where the investigated corroles exhibit a rich redox reactivity, undergoing up to five reversible one-electron-transfer reactions under the different solution conditions. The reversible half-wave potentials for generation of the singly oxidized corroles varied by over 1.0 V with a change in the electron-donating or -withdrawing meso-phenyl substituents and type of anion added to the solution, ranging from E1/2 = 0.83 V in one extreme to -0.42 V in the other. Much smaller shifts in the potentials (on the order of ∼210 mV) were observed for the reversible first reduction as a function of changes of the anion and/or corrole substituents, with the only exception being in the case of CN-, where the E1/2 values in CH2Cl2 ranged from +0.08 V in solutions containing 0.1 M TBAClO4 to >-1.8 V upon the addition of CN-.

An Imidazo[1,2‐a]pyridine Derivative That Enables Selective and Sequential Sensing of Cu2+ and CN− Ions in Aqueous and Biological Samples

AbstractWe report a triazole appended imidazopyridine based chemosensor (probe 1) for sequential detection of Cu2+ and CN− ions using fluorometry. Probe 1 is fluorescent in aqueous acetonitrile (H2O‐CH3CN, 1:1, v/v) when common metal ions are present, but the fluorescence is quenched when Cu2+ is present. The binding mechanism, quantitative determination and the mode of interaction of Cu2+ with probe 1 are explained using fluorescence spectroscopy, electrospray ionization mass spectrometry and Density Functional Theory (DFT) calculations. The observed detection limit for Cu2+ is found to be (18.17×10−6 M) and it is comparable with those reported for other Cu2+ chemosensors. Further, the 1–Cu2+ complex formation is found to be reversible, and this property has been successfully exploited for the quantitative determination of CN− ions in aqueous acetonitrile. Addition of CN– leads to a complete recovery of fluorescence from 1–Cu2+ complex, permitting the real time detection with the lower limit of detection of CN− being 33.57×10−6 M. The observed experimental results are supported by DFT calculations. A possible application of 1–Cu2+ in fluorescence imaging of Rhizoctonia solani mycelia cells, contaminated with CN− ions, is also represented.

Rapid and sensitive determination of Pb2+ in water using chromogenic reagent patterned on nail polish modified filter paper

The current strategy extends the analytical utility of colorimetric spot assay for developing a simple one-step determination of Pb2+ in environmental water samples using the chromogenic reagent 2-(5-Bromo-2-pyridylazo)-5-(diethylamino)phenol (5-Br-PADAP). The established assay was executed on Whatman filter paper modified with commercially available nail polish (NP). Goniometry analysis revealed that the surface of NP modified cellulose surface harbored hydrophobic character (θ ~111º). Scanning electron microscopy (SEM) and surface profilometry techniques satisfactorily recognized the changes in the morphology as well as the roughness upon surface modification. Under the optimized parameters, the assay could be concluded in less than 10 min upon formation of red-colored Pb-PADAP chelate. The figures of merits of the developed method were as follows; limit of detection (LOD=0.01 μg/mL), and linear dynamic range (LDR=0.5–10.0 μg/mL). The estimated assay sensitivity of the developed assay for Pb2+ determination corresponds to 11.4 ΔI/µg/mLPb2+/cm2. In addition to visual detection, data was also quantitated through scoring color intensity of the assay using image analysis software. Selectivity of the assay towards Pb2++ was greatly improved through addition of CN−, I− and F− that would eliminate the interference from most common diverse ions. The developed assay was satisfactorily extended for trace determination of Pb2+ in tap and wastewater samples. The reputable assay has several advantages; inexpensive modification/platform, low reagent/analyte volume requirement, improved specificity and simple read-out. Hence, the recognized assay can be widely implemented for point-of-use application especially in regions dealing with lead toxicity and limited laboratory facilities.

Bithiophene triarylborane dyad: An efficient material for the selective detection of CN− and F− ions

A new fluorescent chemosensor based on bithiophene coupled dimesitylborane (BMB‐1) was synthesized and characterized. BMB‐1 was used for colorimetric and turn‐on fluorescent sensing of cyanide (CN−) and fluoride (F−) ions, in the presence of other competitive anions in an aqueous (CH3CN–H2O) medium. BMB‐1 showed a hypsochromic shift (blue shift) with addition of CN− and F− ions in absorption studies. The lower detection level of CN− and F− ions is 1.37 × 10−9 and 1.75 × 10−9 M, respectively. The BMB‐1 binding mechanism is based on the nucleophilic addition of CN− and F− ions in the internal charge transfer transition of bithio moiety to the boranylmesitylene unit, and the color changes were observed under UV light. This result is further confirmed by Fourier transform infrared spectroscopy, mass spectrometry and density functional theory calculations. Also, the BMB‐1 probe is found to be a good adsorbent for the removal of F− ions in real water samples using the adsorption technique.

A novel uracil-based chemosensor for sequential detection of copper (II) and cyanide ions and its application in real samples

A simple uracil based chemosensor (UraCS) has been developed for sequential detection of Cu2+ and CN− in aqueous acetonitrile solution. The sensor UraCS showed a high selectivity, high sensitivity and quick response to copper ions in the presence of other competing cations including Cd2+, Fe2+, Hg2+, Al3+, Ni2+, Ba2+, Ca2+, Cr3+, Co2+, Zn2+, Cu2+, Pb2+, Ag+, Fe3+ and K+. In the presence of Cu2+, UraCS provided a distinct color change from colorless to dark yellow forming a complex with a 2:1 stoichiometry and reverse color change after addition of CN‾ to the probe containing UraCS-Cu2+ complex. More importantly, the results confirmed that the UraCS has widely linear detection range of 3.0 to 150 μM toward Cu2+ ions. The calculated limit of detection for Cu2+ ions was low as 0.28 μM. Moreover, interaction of UraCS with Cu2+ causes a significant fluorescence quenching at 378 nm. UraCS-Cu2+ complex could be successfully applied to detect cyanide ions via Cu2+ displacement approach. The free UraCS was recovered after adding the CN‾ ions in a few seconds due to the formation of the stable copper cyanide complex Cu(CN)x. The DFT calculation was also performed for better understanding of the Cu2+ sensing mechanism. Furthermore, chemosensor UraCS was successfully utilized in the preparation of test strips and supported silica gel for the detection of Cu2+ and CN− ions from aqueous environment and real water samples.

A coumarin-connected carboxylic indolinium sensor for cyanide detection in absolute aqueous medium and its application in biological cell imaging.

Fluorescent sensor has been noticed in detecting system due to its sensitive, selective, operational simplicity and low cost. We designed a coumarin-connected carboxylic indolium sensor molecule that is water-soluble and cytomembrane-permeable. This infrared (IR) emitter is selectively sensitive towards cyanide detection in aqueous media according to CN- nucleophilic attack on the indole C=N function. Upon the addition of CN- anion, the color of sensor in water varied from blue to colorless by naked eyes and fluorescence quenching was observed by spectroscopic method. This was because the intramolecular charge transfer (ICT) effect occurred when the fluorescent sensor was added with CN-. The minimum detection limit of the sensor's fluorescence response to CN- is 4.44 × 10-7 mol/L. Furthermore, the cytotoxicity test shows the sensor has lower cytotoxicity, and indicates that this sensor can be utilized for practical detection of trace cyanide in wastewater.

A spiropyran-based colorimetric probe for quantitative analysis of cyanide ions in cassava leaves

A synthetic spiropyran derivative (2-(8-(hydroxymethyl)-3′,3′-dimethyl-6-nitrospiro [chromene-2,2′-indolin]-1′-yl)ethanol; SP) was spectroscopically evaluated as a highly selective probe and applied for colorimetric detection of cyanide ion (CN−) in cassava leaves. Upon addition of CN− into a pink solution of SP in THF/H2O (4.5:5.5 v/v, 0.5 mM HEPES at pH 9), a vivid yellow solution of the [MC-CN]− adduct was clearly observed by the naked eye. The spectral change in absorbance of the mixture between SP and CN− was monitored by UV–visible spectroscopy. The adduct formation through nucleophilic addition was confirmed by 1H NMR experiments. Additionally, the results from Job's plot suggested that SP and CN− formed the adduct at a 1:1 stoichiometric ratio with the binding constant of 8 × 104 M−1. The detection limit was determined to be 0.52 μM which is lower than the maximum permissible level of CN− in drinking water (1.9 μM) as approved by WHO. Moreover, the analysis of CN− in cassava leaves using our synthetic SP was demonstrated by both qualitative and quantitative approaches. The average CN− concentration in cassava leaves determined by the SP probe was 204.2 ppm which is comparable to the value obtained from the standard Chloramine-T/Pyridine-barbituric acid colorimetric method (203.6 ppm). The viable paper-test strips of SP were also developed for CN− colorimetric detection.

Controllable and reversible proton transfer for inorganic cyanide visual sensing based on the deprotonation of azo-phenolic hydroxyl group

ABSTRACTMethods for optical detection of inorganic cyanide based on the single molecule sensor with high selectivity and sensitivity have attracted increasing interest recently due to the high toxicity of cyanide ions. In this work, a visual sensor (S1) containing both imidazole NH and azo-phenolic OH was synthesised and characterised. The spectral experimental data indicated that protic aqueous solution facilitated enhancing the selectivity of cyanide ions with the nanomolar-level detection limit in semi-aqueous solution. The visual sensing mechanism arising from the deprotonation of azo-phenolic OH and the enhancement of intramolecular charge transfer could be clearly demonstrated by titration experiments of 1H NMR, HR MS and energy changes between the HOMO−LUMO band gaps. Furthermore, the reversibility and reusability of S1 upon alternating addition of CN− and H+ were studied.

Terpyridyl-based triphenylamine derivatives with aggregation-induced emission characteristics for selective detection of Zn2+, Cd2+ and CN− ions and application in cell imaging

Two terpyridyl triphenylamine derivative luminogens (DTPy-TPA and TPy-TPA) with aggregation-induced emission (AIE) characteristics were designed and synthesized. The number of terpyridyl units of these two compounds has a remarkable effect on the responses towards metal ions. DTPy-TPA with two terpyridyl groups on both sides displayed multi-response to Zn2+ and Cd2+ in THF solution along with distinct absorption and emission spectral changes, and obvious naked-eye color changes. However, TPy-TPA with one terpyridyl phenyl group didn't work. This should be resulted from the formation of supramolecular polymers or oligomers for DTPy-TPA to restrict the intramolecular motions, but dimers for TPy-TPA. Moreover, both of these two compounds in H2O/THF (9:1, v:v) solution could selectively and sensitively detect CN− with distinct fluorescence quenching, which was attributed to the nucleophilic addition of CN− to the α-position of the dicyanovinyl group and thus the free rotation of phenyl groups on TPA. The sensing mechanism of DTPy-TPA or TPy-TPA with CN− was confirmed by 1H NMR titration and Job's plot. Finally, based on their excellent photophysical properties, these two probes were successfully employed to detect CN− in living HEK293 cells using fluorescence bioimaging.

Corrosion Behavior of Bitter Almond Oil During Processing

AbstractThis study aims to explore the corrosion behavior of bitter almond oil (BAO) during processing. Hydrocyanic acid (HCN) and benzoic acid in oil are speculated as the main components that corrode the screw oil expeller. Immersion and simulation corrosion tests are carried out to verify this hypothesis. Immersion test results show that crude BAO (CBAO) containing 5.07 ± 0.06 mg kg−1 benzoic acid and 4.25 ± 0.04 mg kg−1 HCN exhibits corrosive effects on steel. Simulation corrosion test results indicate that the addition of CN− or benzoic acid has significant effect on the corrosion of steel. Specifically, at ≥1 × 104 mg kg−1 benzoic acid concentration or ≥5 mg kg−1 CN− concentration, the mass of steel blocks in oil decreases and the contents of Fe, Zn, Al, and Mg ions in oil increase significantly. Therefore, HCN in CBAO is the main cause of screw oil expeller corrosion in BAO processing and benzoic acid is the secondary cause.Practical Applications: The corrosion behavior of CBAO not only damages the integrity of the screw oil expeller but also increases the dissolution of toxic metals from the components into oil. The study of corrosion has practical value in taking effective measures, such as detoxification before pressing and addition of natural inhibitors, to reduce corrosion and ensure the quality of CBAO. Corrosion study provides the basis for the selection of steel materials of screw oil expeller.

Synergistic effect of fluorescence recovery and enhancement on ultrasensitive visual assay of cyanide anions based on N-Acetyl-L-Cysteine-Capped CdTe quantum dots and carbon dots

Developing a reliable fluorescent nanosensor for cyanide anions (CN−), with the potential to enable visual discrimination by naked eye, is highly sought after yet is limited by low sensitivity and selectivity. Herein based on the synergistic effect of fluorescence recovery and enhancement, a specific dual-emission nano-system was designed for ultrasensitive detection of CN−, by employing carbon dots (peaking at 443 nm) as a reference and N-acetyl-L-cysteine (NALC)-capped CdTe quantum dots (QDs, peaking at 611 nm) as a reporter. The red fluorescence of CdTe QDs is first quenched by Cu2+ primarily with electron transfer. Upon addition of CN−, CN− coordinates with Cu2+ to form [Cu(CN)n](n−1)− complex, causing the Cu2+ to detach from the QDs, and consequently fluorescence recovery. More importantly, the CN− can undergo a nucleophilic addition reaction with the carbonyl group of NALC ligands, inducing 1.3-fold fluorescence enhancement towards the original QDs while the blue fluorescence of carbon dots remains constant. This results the fluorescence intensity ratios (I611/I443) are proportional to the concentrations of CN− in the ranges of 0.02―10 and 15―80 μM, and an ultra-low detection limit down to 10.35 nM is achieved. By using both Cu2+-promoted complexation and addition reaction as recognition units, the present method also showed excellent selectivity for CN− over other coexisting anions. Especially, we have already demonstrated, by spiked tests, the practicability of monitoring the concentration changes of CN− in both environmental water and cassava samples, and further realized visual monitoring of CN− changes in aqueous solution and test paper.

Azobenzene–Hemicyanine Conjugated Polymeric Chemosensor for the Rapid and Selective Detection of Cyanide in Pure Aqueous Media

ABSTRACTA water‐soluble polymeric probe was designed and synthesized that can be used for the colorimetric selective detection of cyanide ions in pure aqueous media. In particular, P1, a water‐soluble random terpolymer (P1) of N,N′‐dimethylacrylamide, 2‐((E)‐4‐((E)‐(4‐((2‐(acryloyloxy)ethyl)(methyl)amino)phenyl)diazenyl)styryl)‐1,3,3‐trimethyl‐3H‐indol‐1‐ium (M1), and N‐(4‐benzoylphenyl)acrylamide was synthesized via traditional free‐radical polymerization. Upon the addition of CN− ions to a P1 solution, a macroscopically detectable color change of the solution from brick red to light yellow took place, which was associated with a low limit of analyte detection (1.23 μM). Notably, P1 exhibited excellent selectivity toward CN− over other anions and biothiols, which may be present in the medium. Such highly selective colorimetric response to CN− by P1 originated from the nucleophilic attack of CN− anions onto the electron‐deficient polarized CN bonds of P1's indolium moieties, resulting in the perturbation of the intramolecular charge transfer process occurring within the probe via destruction of the polymer's extended π‐conjugation. P1 was also immobilized on a quartz slide by spin coating and then exposed to ultraviolet light. The resulting polymeric film displayed a rapid response to CN− consisting in a distinct color change, extending the scope of the usefulness of P1 as a cyanide‐ion probe beyond the solution phase. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 124–131

A novel fluorescent sensor based on 4-(diethylamino)-2-(hydroxy)-phenyl imine functionalized naphthalimide for highly selective and sensitive detection of CN– and Fe3+

In this work, a novel sensor molecule HB1, based on a 4-(diethylamino)-2-(hydroxy)-phenyl imine functionalized naphthalimide derivative, was successfully designed and synthesized. Interestingly, the HB1 showed fluorescence identification ability for CN– in DMSO/H2O (8:2, v/v) solution. After addition of CN– into the HB1 solution, the fluorescence intensity of HB1 solution could be enhanced obviously. The anti-disturbance experiments demonstrated that other anions could not interfere in the detection of CN–. On the other hand, HB1 was capable of dual-channel (absorption and fluorescence) detection of Fe3+ in DMSO solution. With the addition of various metal ions into the HB1 solution, only Fe3+ induced the fluorescence emission of HB1 solution quenching and the colour change, and other metal ions could not interfere in the detection of Fe3+. The limits of detection (LODs) of HB1 for CN– and Fe3+ were 6.30 × 10−8 and 3.95 × 10−8 mol/L, respectively. Importantly, the real sample experiment was carried out by detecting CN– in bitter almonds. Additionally, ion test strips based on HB1 were fabricated, which could act as convenient and efficient test kits for detecting CN– and Fe3+.

Rational design of a colorimetric and fluorescence turn-on chemosensor with benzothiazolium moiety for cyanide detection in aqueous solution.

A novel colorimetric and fluorescence turn-on chemosensor TBB with benzothiazolium moiety has been explored, which exhibited the high selectivity for cyanide ion (CN-) in THF-H2O (2:8, v/v) mixture. The aqueous solution of sensor TBB was scarcely emissive. In the presence of CN- ion, the nucleophilic addition of CN- with the benzothiazolium CN bond of TBB produced the new species TBB-CN, consequently resulting in the intense orange-red emission by aggregation-induced emission (AIE) effect. Meanwhile, the color of solution was changed from orange-yellow to light yellow. The sensing mechanism was verified by Mass spectrometry, NMR analysis and DFT calculations.

Naphthoimidazolium based ratiometric fluorescent probes for F− and CN−, and anion-activated CO2 sensing

The results of the current study show that fluoride and cyanide recognition by two naphthoimidazolium derivatives can be applied to CO2 sensing. Among various anions, only fluoride and cyanide promote changes in absorption and fluorescence wavelegnth maxima of the naphthoimidazolium derivative in CH3CN. The changes are attributed to (C–H)+--anion- ionic hydrogen bonding interactions between the conjugated imidazolium salts and these anions. Especially important is the observations that the fluorescence emission maxima of the naphthoimidazolium derivative at 465 nm undergo hysochromic shifts to 375 nm upon addition of fluoride and cyanide exclusively. The naphthoimidazolium derivatives undergo highly selective changes in their fluoerecence maximum from 465 nm to 375 nm upon addition of CN− even when 2% water is present in the CH3CN solution. Moreover, exposure of the solution of CN− activated naphthoimidazolium derivative to CO2 promotes a red shift of emission maximum back to 465 nm. The results demonstrate that the naphthoimidazolium derivatives can be utilized for anion activated ratiometric sensing of CO2.

Novel cyanide supramolecular fluorescent chemosensor constructed from a quinoline hydrazone functionalized-pillar[5]arene.

Herein, we report a simple and novel approach for the design of fluorescent chemosensor through the self-assembly of functionalized monomer molecules. According to these approach, a novel supramolecular fluorescent chemosensor (SPMS) was successfully constructed by self-assembly of a quinoline hydrazone functionalized pillar[5]arene monomer PM. Interestingly, upon the addition of CN-, the solution of SPMS instantly shows dramatic fluorescent enhancement and emitting bright blue emission. Meanwhile, the fluorescence quantum yields show distinct increase from 0.0582 of SPMS to 0.3952 of SPMS + CN-. The detection limit (LOD) of SPMS for CN- is 9.70 × 10-8 M, which indicated high sensitivity. Moreover, the SPMS is selective for CN- even in the presence of other anions, the fluorescent detection process of SPMS for CN- was not interfered by other competitive anions (F-, Cl-, Br-, I-, N3-, OH-, SCN-, HSO4-, AcO-, H2PO4- and ClO4-). Notably, in the CN- sensing process, the self-assembly structure of the supramolecular chemosensor SPMS didn't show any disassembly. This work provides a novel approach for instant detection of CN- through a self-assembled supramolecular fluorescent chemosensor in aqueous system. Moreover, the test strips based on SPMS were fabricated, which could serve as convenient and efficient CN- test kits.

A dual-function colorimetric probe based on Carbazole-Cyanine dyad for highly sensitive recognition of cyanide and hypochlorous acid in aqueous media

A dual-function colorimetric probe (Cz-Cy7) with an electron-donating carbazole tethered at the central position of heptamethine cyanine was designed and synthesized, and the performance on CN− and HClO detection were systematically investigated. With the addition of CN−, Cz-Cy7 exhibited remarkable changes in both UV–vis and fluorescence spectra with a good linear relationship to CN− concentration, and a discernible color change under daylight was observed. The limit of detection for CN− was found to be 9.1 nM in DMF and 0.09 μM in DMF/H2O. Meanwhile, Cz-Cy7 exhibited a highly sensitive response to HClO in the presence of other ROS (reactive oxygen species) based on the sensing mechanism of oxidative cleavage of olefinic C = = C bond. The limit of detection for HClO was evaluated to be 14 nM in PBS buffer solution (containing 50% CH3CN). More importantly, the probe Cz-Cy7 showed good recovery and analytical precision in real water samples for both CN− and HClO detection, indicating it was feasible and reliable for practical application. Moreover, the test strips loaded with Cz-Cy7 were fabricated and validated to be a portable tool for the efficient detection of CN− and HClO by the naked eye.