Cyanide Sensor Research Articles

A One‐Pot Synthesized Chemodosimetric Chemosensor for Highly Sensitive Cyanide Ion Detection in Aqueous Media and from Tobacco Smoke

AbstractA sustainable future world consistently attributes to the development of eco‐friendly methods and materials for detection and elimination of toxic substances from the environment. While addressing the issues, pyrazole carbonitrile derived Schiff base PYR−TZ has been designed and employed for colorimetric and turn on fluorometric cyanide ion sensing. PYR−TZ demonstrated high cyanide ion (CN−) sensitivity with a 1 : 1 binding stoichiometry in aqueous solution. By preventing intramolecular charge transfer, the PYR−TZ sensor demonstrated excellent selectivity towards CN, which caused a color transition from colorless to yellow and impressive “turn‐on” fluorescence emission. The detection thresholds for CN− are 6.5 nm for absorbance spectra and 0.396 nm emission spectra, respectively. Under typical ecological and physiological settings (pH 1–12), the PYR−TZ sensor can function as an effective chemical sensor for detecting the CN− ions. Additionally, the sensor can find CN in tobacco commercial products like cigarettes and cigars. PYR−TZ is a great cyanide sensor probe that has a number of benefits, which includes simple synthesis, distinct color and emission change, a high degree of selectivity, lesser limit of detection, reversibility, and good anti‐interference ability to analyze solution and tobacco commercial things, together with fluorescence imaging. The theoretical optimized structure and electronic transitions were confirmed by DFT and TDDFT studies. On the basis of theoretical and experimental calculations (DFT), the mechanism of the metal ion complex is postulated.

A Quick, Highly Selective and Sensitive Colorimetric and Fluorimetric Sensor for Cyanide Ion.

A newly developed diindolium moiety has been synthesized and structurally investigated by employing a number of spectroscopic methods like NMR and HRMS in order to serve as a cyanide sensor DI. The interaction between DI and the CN- ion causes a noticeable color shift from pink to colorless, making it easy to detect CN- ions with the naked eye. Besides, the sensor exhibited fluorescence color change from orange to light blue under UV lamp. Sensor DI has remarkable selectivity and sensitivity in distinguishing between CN- and a wide range of interfering anions. The sensing mechanism of sensor DI towards CN- ion involves the nucleophilic addition process of CN- to the electron deficient indolium moiety. The detection limit of cyanide ion by sensor DI is calculated to be 1.4 × 10- 7 M by UV-visible and 8.2 × 10- 8 M by fluorescence technique which are lower than the limit set by WHO. The application of sensor DI for cyanide ion is utilized by making test kit and by taking different sources of water to test the presence of cyanide ion.

Unveiling the unique properties of carbon nitride (C6N8) monolayer as a novel flexible sensor for hydrogen cyanide and hydrogen fluoride: A DFT study

Surge for the advancement of sensor that accurately and selectively detect toxic materials particularly cyanides and fluorides, is expanding every day. Herein, we analyze the sensing ability of carbon nitride (C6N8) monolayer for precise detection of hydrogen cyanide (HCN) and hydrogen fluoride (HF) using DFT approach. Interaction energy analysis reveals that HF binds strongly to C6N8 monolayer which is probably due to chemical bond formation whereas, HCN adsorbed to the surface by weak van der Waals forces. The atom in molecules (AIM), the density of states (DOS), non-covalent interaction (NCI), molecular electrostatic potential (MEP), electron localization function (ELF), frontier molecular orbitals (FMO), and QNBO were used to gain a thorough understanding of the complexation of HCN and HF with monolayer. HCN and HF analytes with C6N8 monolayer exhibit slight variations in band gap energy in FMO analysis (4.206 to 4.267 eV) indicating weak NCIs. Furthermore, MEP map demonstrate that more charge transfer is occurred from the C6N8 monolayer towards HF@C6N8 resulting in a strong ionic bonding. In addition, the existence of non-covalent interactions among complexes confirmed by NCI-RDG and QTAIM analysis. A short recovery period for HCN@C6N8 (1.677 × 10−7 s) makes desorption process simpler. Appreciable selectivity of monolayer towards analytes and prospects of all findings will provide an experimentalist with practical suggestions to build highly sensitive sensors for HCN and HF using C6N8 monolayer.

A cyanoethylene-containing diarylethene derivative: AIEE, photochromism, and dual sensing cyanide ions

An aldehyde-containing diarylethene parent react with the benzothiazole acetonitrile which results in a photochromic aggregation-induced emission enhancement (AIEE) molecule. The title compound emits bright yellow fluorescence (λem = 578 nm) in the solid state, which is contrast to many diarylethene derivatives having serious aggregation-caused quenching (ACQ). Further studies showed the title compound as colorimetric and fluorescent sensing cyanide sensor based on nucleophilic addition reaction with rapid response, excellent selectivity, and high sensitivity. Moreover, practical applications studied showed the title compound is convenient to detect for cyanide ion in food and actual water samples.

A Novel Colorimetric and Fluorometric Dual-Channel Chemosensor based on A Conjugated Perylene-Benzothiazole System for Highly Selective Detection of Cyanide in Aqueous Media.

A novel cyanine compound based on the conjugated perylene-benzothiazole system (PBI) as a colorimetric and fluorometric dual-channel sensor for cyanide (CN- ) detection was synthesized and characterized via UV-vis and fluorescence spectroscopy. PBI exhibited a high sensitivity and rapid optical response for CN- due to the intramolecular charge transfer (ICT) mechanism. The detection limit of PBI for CN- was 1.15×10-7 M in the mixture of DMSO/H2 O (1 : 1, v/v). Moreover, probe PBI demonstrated high selectivity and sensitivity for CN- over other common anions, including Cl- , Br- , F- , I- , AcO- , ClO4 - , HSO4 - , SO4 2- , NO2 - , NO3 - and SCN- . This work provided a simple and effective approach to trace the toxic CN- ion with rapid response, high selectivity, and sensitivity that is possibly applied in environmental control and agricultural management.

New dual-responsive fluorescent sensor for hypochlorite and cyanide sensing and its imaging application in live cells and zebrafish

Excessive levels of cyanide (CN−) and hypochlorite (ClO−) anions are the significant threats to the human health and the environment. Thus, great efforts have been to design and synthesize molecular sensors for the simple, instantaneous and efficient detecting environmentally and biologically important anions. Currently, developing a single molecular sensor for multi-analyte sensing is still a challenging task. In our present work, we developed a new molecular sensor (3TM) based on oligothiophene and Meldrum's acid units for detecting cyanide and hypochlorite anions in biological, environmental and food samples. The detecting ability of 3TM has been examined to various testing substances containing amino acids, reactive oxygen species, cations and anions, showing its high selectivity, excellent sensitivity, short response time (ClO−: 30 s, CN−: 100 s), and broad pH working range (4–10). The detection limits were calculated as 4.2 nM for ClO− in DMSO/H2O (1/8, v/v) solution and 6.5 nM for CN− in DMSO/H2O (1/99, v/v) solution. Sensor 3TM displayed sharp turn-on fluorescence increasement (555 nm, 435 nm) and sensitive fluorescence color changes caused by CN−/ClO−, which is ascribed to the nucleophilic addition and oxidation of ethylenic linkage by cyanide and hypochlorite, respectively. Moreover, sensor 3TM was applied for hypochlorite and cyanide detecting in real-world water, food samples and bio-imaging in live cells and zebrafish. To our knowledge, the developed 3TM sensor is the seventh single-molecular sensor for simultaneous and discriminative detecting hypochlorite and cyanide in food, biological and aqueous environments using two distinct sensing modes.

A colorimetric and turn-on fluorescent sensor for cyanide and acetate-based Schiff base compound of 2,2′-((1E,11E)-5,8-dioxa-2,11-diazadodeca-1,11-diene-1,12-diyl)bis(4-((E)-phenyldiazenyl)phenol)

A novel Schiff base-based sensor (L) has been designed, synthesized, and developed as a fluorescent and colorimetric sensor for cyanide and acetate. This L exhibited a quick response with rapid sensitivity to CN– and AcO- through a remarkable color change from yellow to red which was detectable by the naked eyes. It also sensed CN– and AcO- in a fluorescent way via an enhancement in fluorescence intensity. The interaction between L and anions (CN– and AcO-) was investigated by using UV–Vis studies, and 1H NMR titration. The theoretical DFT calculations were also employed to support the results, which displayed good agreement with the experimental value acquisition. As the detection limit for cyanide and acetate were 2.1 × 10-9 M and 1.7 × 10-9 M; respectively, low concentrations of these anions could be detectable in the proposed L sensor. In addition, L showed significant reversibility of CN– detection by using Cu2+ as a proper reagent with two different sensing methods including color change and UV–Vis. Last but not least, L could be applied to rapidly detect CN– in a wide range of pH. As a result, the proposed sensor is promising to identify cyanide and acetate in practical applications in medical, biological, and chemical fields.

Organochalcogen substituted dimesityl borane-imidazoles as fluorogenic fluoride and cyanide sensors in aqueous media.

Natural and anthropogenic activities leading to excessive toxic biological anions in water have warranted the development of anion sensors, especially for cyanide (CN-) and fluoride (F-) ions in aqueous media. Herein, a contemporary synthetic route to embed organochalcogen compounds (-SPh and -SePh) in a boron-functionalized imidazole scaffold via metal halogen exchange is reported. Upon methylation, fluorogenic compounds 5-dimesitylboryl-2-phenylthio-1-methylimidazole (7) and 5-dimesitylboryl-2-phenylselone-1-methylimidazole (8) form the corresponding imidazolium salts, 5-dimesitylboryl-2-phenylthio-1-methylimidazolium iodide (9) and 5-dimesitylboryl-2-phenylselone-1-methylimidazolium iodide (10), which are non-luminescent. All of the compounds are thoroughly characterized, and their utility in sensing F-, CN-, and various other biologically relevant halides has been studied through UV-vis and fluorescence spectroscopy. The substrates and products of 1 : 1 binding of anions (F-/CN-) with the compounds have been established by spectroscopy, spectrometry, single-crystal X-ray crystallography, and first principles quantum mechanical theoretical calculations. The superior binding ability and micromolar sensitivity towards CN- ions over other anions in aqueous media were elucidated. The reversibility of compound 7 was also tested and it was found that fluoride binding was reversible while cyanide binding was not.

Efficient cyanide sensing using plasmonic Ag/Fe3O4 nanoparticles.

In the line of our previous studies, we have reported a developed sensitive and selective probe for cyanide detection based on Ag/Fe3O4 nanoparticles (NPs) with an extremely low limit of detection at the level of ng per milliliter. Herein, we report the improvement of the easy-to-make magnetic silver nanoparticle-based sensor system for cyanide determination in an extended calibration range with higher selectivity and precision. As far as our knowledge is concerned, the detectable linear range from 1.0 nM to 160 μM (0.026 ng mL-1 to 4.16 μg mL-1) of the improved simple highly precise technique represents the widest assay that has been reported so far. The method is based on strong enhancement of scattered light of the plasmonic nanoparticles and simultaneously cyanide fluorescence quenching. Although the fluorescence of cyanide is highly selective and precise, its intensity is poor. On the other hand, the strongly enhanced Rayleigh signal has a low repeatability. We proposed a method to remove the interference and obtained an effective factor that is directly proportional to cyanide concentration utilizing both above signals simultaneously. In this work, Ag/Fe3O4 NPs have been synthesized easily using a green preparation method and the NPs were consequently characterized using powder XRD, UV-Vis absorption spectroscopy, transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). A combination of absorption, Rayleigh and fluorescence characteristics were used for detection of cyanide in real samples and an overview of recently reported sensors for cyanide was also provided.

Electronic band gap on graphene induced by interaction with hydrogen cyanide. An DFT analysis

The interaction of cyanide (HCN) with graphene (SGL) is studied using the Density Functional Theory in the van der Waals scheme, using an exchange and correlation functional with the Berland and Hyldgaard (BH) parametrization and non-local norm conserving pseudopotentials. 12 geometric configurations of HCN-SGL system are analyzed in detail. Our results show that the bonding HCN-SGL produces a charge redistribution and localized states into the conduction and valence bands of graphene monolayer. Also, the HCN-SGL interaction induces an energy gap in graphene, which is robust under electric fields, whose value depends both on the cyanide orientation respect to monolayer as the cyanide’s atom interacting with the monolayer. This results guide the potential use of graphene as a cyanide sensor, given the changes in resistivity of the monolayer, as well as the development of electronic nano-devices that require strong localized states in the presence of electronic fields.

Molecular simulations of CRANADs to disclose a specific cyanide sensor in aqueous media

Chemical pollutants are the major contaminants in natural water samples and can be introduced either through natural processes or as a result of human activities. Some of the cations and anions such as cyanide, lead, mercury, and arsenic are toxic even at extremely low concentrations. The fatal effects of cyanide ions on the ecosystem have led to extensive research in the advancement of methods for rapid and specific detection of cyanide. We already reported the theoretical and experimental studies on the specific cyanide sensing capacity of the curcuminoid-BF2 complex, CRANAD-1. However, the theoretical investigation of the sensing mechanism of these types of CRANADs pointed out the key structural features which are capable of generating a better fluoroprobe for the rapid detection of cyanide in aqueous media even in trace quantities. Herein, we designed a novel selective and efficient fluorescent probe for cyanide detection based on these features. The DFT (Density Functional Theory) approach explores the significance of the probe in the quantitative detection of cyanide concentration in natural water samples. A comprehensive examination of the binding energies of the designed CRANADs in presence of various anions such as CN−, F−, Cl−, Br−, AcO−, SO42−and NO3− were carried out using the B3LYP level of density functional theory using SDD and 6-311++G** basis sets. Theλmaxabsorption values, FMO (Frontier Molecular Orbital), ESP (Electrostatic potential) plots and NBO (Natural Bond Orbital) analysis reveal the better cyanide sensing ability of the D–A–D (Donor-Acceptor–Donor) type CRANAD scaffold.

Bis-BODIPY-based fluoride and cyanide sensor mediated by unconventional deprotonation of C−H proton

A novel bis-BODIPY-based colorimetric and fluorescent sensor (BODIPY-NN) for F− and CN− recognition with high selectivity and high sensitivity is reported. The designed sensor, BODIPY-NN, was synthesized by a one-step click reaction of azido-BODIPY with N,N′-dipropargylbenzene-1,2-diamine. The BODIPY-NN sensor displays a marked color change from pink to colorless and a remarkable turn-off fluorescence behavior exclusively toward F− and CN− ions. Analysis of 1H, 13C, 19F, 11B NMR and mass spectra, together with theoretical calculations, provides insight into the mechanism of anion binding to BODIPY-NN. The sensing mechanism was found to be unconventional deprotonation at pseudo-benzylic carbons attached to BODIPY cores in the presence of F− and CN− ions, to form the less highly conjugated BODIPY moieties, thereby displaying fluorescence quenching. Addition of water in the BODIPY-NN + F− system regenerates the sensor with restoration of its spectroscopic properties. In contrast, the CN− ions permanently disrupt the BODIPY moieties by nucleophilic displacement at the central boron atoms, which is irreversible upon addition of water. The detection limits for F− and CN− in THF are 83 and 72 nM, respectively. In particular, BODIPY-NN embedded in cetyltrimethylammonium micelles can be used as colorimetric detection of CN− ions in aqueous media.

Colorimetric and selective turn-on fluorescent sensor for cyanide via aggregation-induced enhanced emission (AIEE)

Colorimetric and selective turn-on fluorescent sensor for cyanide via aggregation-induced enhanced emission (AIEE)

Designing Low-Molecular-Weight Organogelator as a Dual-Channel Cyanide Sensor Based on Gelation-Induced Enhanced Emission

Designing Low-Molecular-Weight Organogelator as a Dual-Channel Cyanide Sensor Based on Gelation-Induced Enhanced Emission

A molecular probe layer modified organic thin film transistor on flexible platform for next generation cyanide sensor

Organic thin film transistor (OTFT) based cyanide (CN−) sensor can be of an intense interest due to its simple operation, high sensitivity, system on chip (SoC) integration capacity and applicability towards environmental safety. So, mechanical flexibility of such sensors can extend them to conformable, bio-compatible and wearable applications. In our recent work, a novel OTFT based highly sensitive and mechanically flexible platform was developed to detect CN− in aqueous medium. The sensor was fabricated on a flexible polyethylene terephthalate (PET) substrate by simple spin coating and operated at a very low voltage of −3 V. For the sensing element, a chemically active dansyl-dervatized-triazole linked glucopyranosyl conjugate (DTGC) was used as a molecular probe on the semiconducting poly (3-hexylthiophene) P3HT layer in the device structure. The fabricated sensor was characterized electrically while using an aqueous solution of tetrabutylammonium cyanide (TBAC) as an analyte. Significant changes in device characteristics including 0.4 V shift in threshold voltage, 0.2 cm2v−1s−1 increment in mobility and 2 μA increase in drain current were observed for the OTFT based sensor with presence of CN− analyte. The concentration of the CN− was then varied and thus the minimum detection limit was found to be 1 μM. The sensor also exhibited excellent mechanical flexibility with its stable operation even up to a bending with 5 mm of bending radius. The sensing mechanism of the developed sensor has been explained through the possible charge transfer phenomena from the host semiconductor due to a chemical reaction between the probe layer and the analyte. The sensititvity and chemical reactivity of the molecular probe to the CN− were further confirmed from the microscopic studies and the change in the visual appearance (colour) of the probe with the presence of aqueous CN−.

Rapid and Highly Selective BODIPY Based Turn‐Off Colorimetric Cyanide Sensor**

AbstractCyanide ion (CN− ion) is one of the most harmful inorganic pollutants wasted by various industrial processes. Although some spectroscopic methods are being used, these methods need advanced instrumentation and have high detection limits. Because of this, rapid, low‐cost and sensitive methods are highly required to detect CN− ion. Chemosensor application is one of the most useful methods for selective detection of the target analyte. BODIPY (boradiazaindacene) dyes are one of the promising candidates for these types of applications because of the unique optical and photophysical properties. Here, we report the first application of the meso‐formyl‐BODIPY dye‐based, rapid and naked‐eye CN− ion sensor application depending on the reaction of CN− ion and aldehyde functionality of the meso‐formylated BODIPY derivative (BODIPY‐BAL). Absorption and emission experiments were successfully conducted. Additionally, colorimetric tests were performed in solution and on test strips. The limit of detection of the chemosensor was calculated as 10.4 μM. Real sample experiments in seawater were also performed and CN− ion was detected at 50 μM concentration, which is the limit level of CN− ion concentration causes acute effects determined by the U.S. Environmental Protection Agency (EPA).

A Molecular Swan: Naphthalene-hydrazone-based π···hole-coupled electron-deficient naked-eye selective colorimetric cyanide sensor

A Molecular Swan: Naphthalene-hydrazone-based π···hole-coupled electron-deficient naked-eye selective colorimetric cyanide sensor

A isophorone based colorimetric and ratiometric probe: Synthesis and rapid detection of cyanide in aqueous medium and its application in bioimaging

A simple colorimetric and fluorescent sensor for cyanide based on phenolic substituted dicyanoisophorone derivative (2) has been synthesized. The absorption spectra of chemosensor 2 showed large bathochromic shift (ca. 240 nm) upon titration with CN− while the solution color changed from yellow to green. The absorption ratios (A685/A446) responses of chemosensor 2 showed a favorable linear relationship with the CN− concentration and the detection limitation had been calculated to be 0.15 μM. Meanwhile, the fluorescence intensity of 2 can be quenched upon reacting with CN− over other anions. More importantly, chemosensor 2 can react instantaneously with cyanide in aqueous solution, and to visualize CN− in living HeLa cells by means of dramatic decrease of fluorescence intensity. Thus, the present sensor could be applicable in detecting cyanide ion both in natural water samples and biological systems conveniently.

Naked-eye colorimetric and turn-on fluorescent Schiff base sensor for cyanide and aluminum (III) detection in food samples and cell imaging applications

A new efficient Schiff base sensor SB3 for fluorescent and colorimetric “naked-eye” “turn-on” sensing of cyanide anion (CN–) with excellent sensitivity and selectivity was developed. The 4,4'-(perfluoropropane-2,2-diyl)bisphenol group and two phenyl groups were covalently linked by two C = N bonds to extend the conjugation length. The four hydroxyl groups can improve the water solubility of the SB3 sensor. The SB3 sensor exhibited high specificity towards CN− by interrupting its intramolecular charge transfer, resulting in a color change and remarkable “turn-on” green fluorescence emission. The sensing mechanism is caused by the nucleophilic addition of CN– toward imine groups of the SB3 sensor, leading to breaks of the conjugation, fluorescent spectral changes, and color change. It was confirmed by 1H NMR titration and Mass spectra. The detection limits for CN– and Al3+obtained by fluorescence spectrum are 0.80 µM and 0.25 µM, respectively. The SB3 sensor can act as an efficient chemical sensor for detecting the CN– and Al3+ ions under common environmental and physiological conditions (pH 5–12). Besides, the sensor can also detect CN− in food materials (such as sprouting potatoes and cassava flour) and imaging CN−in living cells with strong “turn-on” fluorescence at 490 nm. SB3 is an excellent CN– sensor that exhibits some advantages, including easy synthesis, distinct fluorescence and color change, high selectivity, low detection limit, and good anti-interference ability to analyze solution and food samples, together with fluorescence cell imaging.

Pyrene-Hydrazone-π···Hole Coupled Turn-on Fluorescent and Naked- Eye Colorimetric Sensor for Cyanide: Role of Homogeneous π-Hole Dispersion in Anion Selectivity.

A pyrene based probe associated with π···hole - hydrazone as one of the recognizing elements is synthesized and its turn in to a selective colorimetric and turn-on fluorescent sensor, (L3) for cyanide anion. This chemo sensor show high selectivity towards cyanide anion through photo electron transfer (PET) mechanism. The binding strength and sensitivity of the chemo sensor L3 towards cyanide are found to be 2.0 X 104, and 4.44 x 10-4 respectively. We have compared this high selectivity of the receptor towards cyanide, with our previously reported receptors L1 and L2. The detailed UV-Vis, Emission, 1H-NMR, IR spectroscopic and Molecular Electrostatic Potential (MEP) studies reveals that the homogeneous π···hole dispersion in the aromatic ring governing the selectivity of the receptor towards cyanide anion. Such a positive π···hole homogeneous dispersion is missing in the case of sensor L2, instead we have polarized π···hole dispersion towards 2ndand 4thposition of di-nitrophenyl chromophoric unit in L2.