Cyanide Research Articles

Synthesis and Spectroscopic Characterization of Selected Water-Soluble Ligands Based on 1,10-Phenanthroline Core.

Water-soluble ligands based on a 1,10-phenanthroline core are relatively poorly studied compounds. Developing efficient and convenient syntheses of them would result in new interesting applications because of the importance of 1,10-phenanthrolines. In this manuscript, we describe novel and practical ways to introduce a carboxyl and, for the first time, a phenol and dithiocarboxyl group under mild reaction conditions. This strategy enables highly efficient and practical synthesis of suitable organosulfur compounds with high added value, high chemoselectivity, and a broad substrate range. We present the selective conversion of a hydroxydialdehyde in the form of 10-hydroxybenzo[h]quinoline-7,9-dicarbaldehyde into its derivative, unique hydroxydicarboxylic acid, by an oxidation procedure, giving 10-hydroxybenzo[h]quinoline-7,9-dicarboxylic acid. A similar procedure resulted in the formation of 9-methyl-1,10-phenanthroline-2-carboxylic acid by oxidation of commercially available neocuproine. An alternative method of obtaining 1,10-phenanthroline derivatives possessing carboxylic acid group can be based on the hydrolysis of ester or nitrile groups; however, this synthesis leads to unexpected products. Moreover, we apply Perkin condensation to synthesize a vinyl (or styryl) analog of 1,10-phenanthroline derivatives with phenol function. This reaction also demonstrates a new, simple, and efficient strategy for converting methyl derivatives of 1,10-phenanthroline. We anticipate that the new way of converting methyl will find wide application in chemical synthesis.

Onset of Nitriles Hydration with an Environmentally Benign Catalyst: in-Water versus on-Water Conditions.

The reaction yield of nitriles hydration using a catalyst depends on the aqueous medium. Using ab initio molecular dynamics, we probed whether "in-water" (in bulk medium) or "on-water" (at the interface with vacuum) conditions can change the onset of the reaction. Investigating a hydrogen-bond mediated mechanism, the lifetimes of the intermolecular interaction between benzonitrile and choline in the two protocols were compared, and the diffusion of the hydroxide anion around the cyano group was discussed.

Synthesis and characterization of chemosensor: Investigation of cyanide sensing and study as live cell imaging

Chemosensor A , (E)-(4-(2-((2-hydroxynaphthalene-1-yl)methylene)hydrazinyl)benzonitrile has been synthesized by condensation of 4-cyanophenylhydrazine hydrochloride with 2-hydroxy-1-naphthaldehyde in ethanol solvent at ∼80°C. The chemosensor A , has been characterized by FT-IR, ESI-MS and 1H-NMR spectroscopic techniques. The chemosensor A has been investigated for selective cyanide ion sensing ability through UV–visible and fluorescence spectra. Further the chemosensor A was also employed as live cell imaging reagent for intra-cellular detection of cyanide ion in SW480 cells.

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Azepine ring is a prominent structural scaffold in biologically significant molecules. This study demonstrates a Ni(II)‐catalyzed alkyne functionalization/cyclization cascade reaction of alkyne‐tethered malononitriles, involving intermolecular regioselective arylation of the alkynes and desymmetrizing addition onto the nitrile group, to access azepine derivatives. This strategy introduces an all‐carbon quaternary stereocenter and an unprotected imine functionality simultaneously to the azepine scaffold, showing great promise for subsequent transformations. More details are discussed in the article by Liu et al. on page 873—878.image

Improved thermoelectric properties by copolymerization of conducting with insulating monomers on carbon nanotubes

In the present work, development of carbon nanotube (CNT)/poly(conducting-co-insulating monomer) structures was proposed to improve the thermoelectric (TE) performance in CNT/polyaniline (PANI) composites. To check the validity of this idea, we prepared multiwalled carbon nanotube (MWNT)/poly(aniline-co-acrylonitrile) composites by in-situ inverted emulsion copolymerization, and applied secondary doping with camphorsulfonic acid in m-cresol medium prior to the investigation of TE properties. The samples were characterized by FT-IR, UV–Vis, 1H NMR, DSC, GPC, CHNS elemental analysis, intrinsic viscosity, SEM, XRD, electrical resistance, Seebeck coefficient, thickness, and Hall measurements. We report that nitrile groups were hydrolyzed during the polymerization reactions to provide a polymer structure exhibiting aniline, acrylamide, acrylic acid, and glutarimide groups. Further, the poly(aniline-co-acrylonitrile) that prepared in the present work were random copolymers. Importantly, we found that 30 % MWNT/70 % poly(90ANI-co-10AN) composite exhibited a 63 % higher power factor (PF) of 5.48 μW/mK2 (σ: 225 S/cm, S: 15.6 μV/K) at 35 °C than that of 30 % MWNT/70 % PANI, which exhibited a PF of about 3.37 μW/mK2 (σ: 238 S/cm, S: 11.9 μV/K). This was ascribed to the decrease of carrier concentration together with the increase of carrier mobility in the 30 % MWNT/70 % poly(90ANI-co-10AN) composite as compared to the 30 % MWNT/70 % PANI.

Cryogenic to high temperature measurements in gas flows by femtosecond laser-induced CN luminescence

Temperature is a crucial parameter of gas flow fields. Here, we present a novel thermometry technique for gas flow based on femtosecond laser-induced cyano (CN) luminescence. Specifically, a femtosecond laser with a central wavelength of 267 nm is used to induce CN violet emissions in a nitrogen flow seeded with a trace amount of methane. The spectral peak of CN B2Σ+- X2Σ+ (0,0) transitions shift to longer wavelengths with increasing temperatures, and the concentration of methane does not influence this spectral shift. The calibration curve of the spectral peak position and the temperature ranging from 93 to 1028 K is obtained through the experiment, and the curve exhibits a nearly linear trend in the low-temperature regime, and an uncertainty of 3.6 % at 173 K is obtained. The technique's wide temperature measurement capability makes it suitable for gas flow temperature measurements, particularly in environments with significant temperature variations, such as wind tunnels.

Excited state dipole moments of two dicyanobenzene isomers from thermochromic shifts and ab initio calculations

The excited state dipole moments of two positional isomers of dicyanobenzene have been determined from thermochromic shifts of the absorption and fluorescence emission spectra in ethyl acetate solution and compared to the results of ab initio calculations. We found that the dipole moments of excited states from thermochromic shifts closely resemble the ab initio values of the isolated molecule, while the results of conductor-like screening model (COSMO) using the same wave function model as for the isolated molecule, shows considerable deviations from the experimental values. It is shown that the dipole moments of the two cyano groups add up vectorially for both the ground and excited states.

An ultra-photosensitive viologen-based hybrid crystalline material with unconventional transfer pathways

Viologen units are widely used in UV/X-ray detection, photoelectric detection, intelligent anti-counterfeiting, and inkless printing owing to their excellent photo-induced electron transfer (PET). In the previous research, the traditional electron transfer channel types of highly photosensitive viologen-based PET materials were mostly O/X … N (X=Cl, Br, I). In this work, we synthesized a photochromic 0-dimensional supramolecular, [Cd1.5(m-CBbpy)(Cl)4(DMA)]n (1). The electron transfer type of 1 is unconventional Cl⋯H–C, which has an ultra-sensitive response to UV and indoor light. (after 0.3 s under 135.2 mW cm−2 Xe lamp, UV absorption can reach 1/3 of the light saturation; after 20 min under indoor light, the color of 1 turned blue). This is because by introducing more Cl− as electron donors, the cyano group (–CN) on the m-CBbpy·Cl ligand enhances the electron acceptance ability, and the charge interaction formed by Cl− and m-CBbpy+ assists electron transfer (ET). In addition, 1 has amine chemochromism, electrochromism, and wide photocurrent response from 375 to 1850 nm. Therefore, 1 is an excellent material for light/amine/electrical stimulation response and a candidate material for photoelectric detection in the UV–Vis-SWIR region. And it provided clues for developing highly photosensitive viologen material.

Coumarin Linked Cyanine Dye for the Selective Detection of Cyanide Ion in Environmental Water Sample.

A benzoxazole-coumarin-based probe BOC, was synthesized and validated for its anion sensing ability and found to be effective in recognizing cyanide ions. Upon addition of cyanide, a spontaneous color change was observed that was visible to the naked eye. The sensitization process takes place with nucleophilic addition, and the cyanide ion added to the probe disrupts the intra molecular charge transfer transition (ICT) between the donor and acceptor units, causing the pink colored probe to become yellow. Ultraviolet and fluorescence methods were applied to measure the detection limits of probes with added cyanide ions, which were found to be 3.47 µM and 2.48 nM. The stoichiometry of the probe with the cyanide ion was determined by the Job's method, NMR titration, and mass spectrometry and was found to be in a 1:1 ratio. The results obtained from the visual and UV-visible spectral studies are justified by theoretical calculations. The cyanide-loaded probe induced visual changes, which enabled the development of a test strip for field application, and the prepared strip can be used to detect the ppm level of cyanide in water samples. The developed probe, BOC, can be used to detect cyanide ions in various water samples.

Pre-oxidized and composite strategy greatly boosts performance of polyacrylonitrile/LLZO nanofibers for lithium-metal batteries

The active cyano-group in polyacrylonitrile has severe passivation of lithium anode under larger current density, which restricts the wide application of polyacrylonitrile(PAN) in lithium metal batteries. Herein, in order to address the excessive passivation of lithium metal by PAN, inspired by the pre-oxidation of carbon fibers, PAN was pre-oxidized at 230 °C, which transformed part of the cyano group into a more chemically stable cyclized structure. The electrochemical and mechanical properties of the composite solid electrolyte were effectively improved by introducing the fast ionic conductor Li6.25La3Zr2Al0.25O12 into PAN by electrospinning. The oxidized PAN-based composite solid electrolyte presents high ionic conductivity (3.05 × 10−3 S·cm−1) and high lithium transference number of 0.79 at 25 °C, further contributing to a high electrochemical window (5.3 V). The solid-state batteries assembled by Li||10 wt%-LLZAO@230-oxy-PAN||NCM523 behave superb electrochemical performance, delivering a high initial discharge capacity of 157 mAh g−1 at 0.2 C. After 100 cycles, the capacity retention was 93.3 %, indicating the electrolyte displays great electrochemical stability. This work provides new insights into the structural design of polymer-based high-voltage batteries.

A homogeneous carbon nitride nanomodifier for promoting the water permeation of polyamide desalination membranes

Nanomaterial modification provides an effective way to enhance the separation performance of nanofiltration membranes, but the limited hydrophilicity of conventional nanostructures causes their poor solubility in solvents, affecting the quality of polyamide membranes for performance enhancement. Herein, we explored quasi-water soluble carbon nitride as a homogeneous modifier to improve the nanofiltration performance of polyamide membranes. With sufficient hydroxyl, amino, and cyano groups, the introduced quasi-water soluble carbon nitride significantly enhanced the surface hydrophilicity of the support membrane, resulting in the formation of an ultrathin functional layer for high-efficiency desalination. The high permeation flux of 108.64 L m-2h−1 (4 bar) was even twice and three times higher than those of the pristine polyamide membrane and commercial nanofiltration membranes, with a high Na2SO4 barrier rate of 98.84 % and a Cl-/SO42- selectivity of 76. This work provides an effective way to precisely regulate the structure of nanofiltration membranes for high-performance water purification.

Rapid ion conduction enabled by synergism of oriented liquid crystals and Electron-Deficient boron atoms in multiblock copolymer electrolyte for advanced Solid-State Lithium-Ion battery

Liquid crystals (LCs) with characteristics of self-orientation have exhibited superiorities in construction of ordered ion channels for rapid Li-ion transport. Herein, reversible addition-fragmentation chain transfer (RAFT) polymerization is employed to synthesize a unique type of boron-containing LCs based ABCBA type multiblock copolymers for the first time. The composite block copolymer electrolytes (BCPEs) are fabricated by introducing the copolymer electrolytes into glass fiber separator via solution-casting method. Noteworthily, LCs can not only provide ordered ion channels for efficient ion conduction, but also ameliorate the mechanical strength. Meanwhile, the nitrile groups with high polarity from LCs are able to further facilitate lithium salt dissociation and reinforce electrochemical stability of the system. Crucially, boron elements with electron deficiency can anchor anions and adsorb impurities to endow BCPEs with boosted ion transport capability and sufficient electrochemical stability. Consequently, the well-designed electrolyte shows high ionic conductivity of 1.13 × 10−4 S cm−1 (30 °C), and broadened electrochemical stability window of 4.85 V. Impressively, the assembled Li/LiFePO4 cells and even Li/LiMnxFe1-xPO4 high-voltage cells exhibit remarkable performances. This work provides a synthetic strategy of structure-controlled polymer electrolyte matrix and illustrates that the BCPEs are definitely a category of satisfactory electrolyte candidate for high-performance solid-state lithium-ion batteries.

Template-Free Synthesis of Boron-Doped Graphitic Carbon Nitride Porous Nanotubes for Enhanced Photocatalytic Hydrogen Evolution.

The photocatalytic activity of g-C3N4 can be enhanced by improving photoinduced carrier separation and exposing sufficient reactive sites. In this study, we synthesized B-doped porous tubular g-C3N4 (BCNT) using a H3BO3-assisted supramolecular self-template method, wherein H3BO3 helped in B-doping, building a porous structure, and maintaining one-dimensional nanotubes. The tubular structure had an ultrathin tube wall and large aspect ratio, which are conducive to the directional transmission and separation of photogenerated carriers; moreover, the abundant pore structure of the tube wall could fully expose the reactive sites. The introduction of B and the cyano group modulated the bandgap of g-C3N4 and elevated the position of the conduction band, thus enhancing the photoreduction ability and effectively improving the hydrogen evolution performance. Consequently, the hydrogen evolution of BCNT-2 (220.8, 53.2 μmol·h-1) was 1.82 and 1.54 times that of ultrathin g-C3N4 nanosheets (CNN, 121.3, 34.6 μmol·h-1) under simulated sunlight and LED lamp irradiation, respectively. Thus, this work provides in-depth insights into the rational design of one-dimensional g-C3N4 nanotubes with high hydrogen evolution activity under visible irradiation.

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.

Cyano-Coordinated Tin Halide Perovskites for Wearable Health Monitoring and Weak Light Imaging.

Low-toxicity tin halide perovskites with excellent optoelectronic properties are promising candidates for photodetection. However, tin halide perovskite photodetectors have suffered from high dark current owing to uncontrollable Sn2+ oxidation. Here, 2-cyanoethan-1-aminium iodide (CNI) is introduced in CH(NH2)2SnI3 (FASnI3) perovskite films to inhibit Sn2+ oxidation by the strong coordination interaction between the cyano group (C≡N) and Sn2+. Consequently, FASnI3-CNI films exhibit reduced nonradiative recombination and lower trap density. The self-powered photodetector based on FASnI3-CNI exhibits low dark current (1.04 × 10-9 A cm-2), high detectivity (2.2 × 1013 Jones at 785nm), fast response speed (2.62 µs), and good stability. Mechanism studies show the increase in the activation energy required for thermal emission and generatedcarriers, leading to a lower dark current in the FASnI3-CNI photodetector. In addition, flexible photodetectors based on FASnI3-CNI, exhibiting high detectivity and fast response speed, are employed in wearable electronics to monitor the human heart rate under weak light and zero bias conditions. Finally, the FASnI3-CNI perovskite photodetectors are integrated with a 32×32 thin-film transistor backplane, capable of ultraweak light (170 nW cm-2) real-time imaging with high contrast, and zero power consumption, demonstrating the great potential for image sensor applications.

Iron-Catalyzed Cyanide-Free Synthesis of Alkyl Nitriles: Oxidative Deconstruction of Cycloalkanones with Ammonium Salts and Aerobic Oxidation.

A sustainable, cyanide-free synthesis of alkyl nitriles via the aerobic oxidative deconstruction of unstrained cycloalkanones with ammonium salts has been developed. Using inexpensive and stable ammonium salts as the nitrogen source, a variety of alkyl nitriles containing a distal carbonyl group were obtained in good yields under visible-light-promoted iron catalysis. This protocol is characterized by mild conditions, abundant and environmentally benign materials, and high atom and step economy with minimal waste generation. The primary mechanism study revealed that 1O2 is likely to be involved in this reaction.

Amino-Acid-Encoded Bioinspired Supramolecular Self-Assembly of Multimorphological Nanocarriers.

Supramolecular self-assembly has emerged as an efficient tool to construct well-organized nanostructures for biomedical applications by small organic molecules. However, the physicochemical properties of self-assembled nanoarchitectures are greatly influenced by their morphologies, mechanical properties, and working mechanisms, making it challenging to design and screen ideal building blocks. Herein, using a biocompatible firefly-sourced click reaction between the cyano group of 2-cyano-benzothiazole (CBT) and the 1,2-aminothiol group of cysteine (Cys), an amino-acid-encoded supramolecular self-assembly platform Cys(SEt)-X-CBT (X represents any amino acid) is developed to incorporate both covalent and noncovalent interactions for building diverse morphologies of nanostructures with bioinspired response mechanism, providing a convenient and rapid strategy to construct site-specific nanocarriers for drug delivery, cell imaging, and enzyme encapsulation. Additionally, it is worth noting that the biodegradation of Cys(SEt)-X-CBT generated nanocarriers can be easily tracked via bioluminescence imaging. By caging either the thiol or amino groups in Cys with other stimulus-responsive sites and modifying X with probes or drugs, a variety of multi-morphological and multifunctional nanomedicines can be readily prepared for a wide range of biomedical applications.

A Chromogenic Probe for Detection of Biologically Important Anions and its Implications for Designing Molecular Logic Gates.

Detection of fluoride (F-), acetate (AcO-), and cyanide (CN-) anions is vital from the biological and environmental aspects. In the present contributions, we have introduced a simple Salen-type chromogenic sensor, BEN, to detect these biologically important anions. Changes in UV-visible absorption spectra and color of BEN solution from very pale yellow to pink color are similar for each of these anions and found to be reversible only in the case of F- ions in attendance of HSO4- ions. The estimated limit of detection of BEN solution for detecting F-, AcO-, and CN- anions is found to be below the micromolar (μM) concentration level. Our fabricated handy paper test kit is suitable for qualitatively naked-eye detection of the anions. An immediate quantitative estimation of these important anions is possible using our BEN employing a smartphone, avoiding any costly experimental setup.

Synthesis, crystal structure investigation and computational studies binding of (7S,8R)-7-acetyl-8-(4-chlorophenyl)-3-(ethylthio)-1,6-dimethyl-7,8-dihydroisoquinoline-4-carbonitrile with monoamine oxidase B

This work reports the preparation of a new dihydroisoquinoline derivative whose structure was characterized by IR, NMR (1H, 13C), MS and verified through single-crystal X-ray analysis. The mean planes of the acetyl and 4-chlorophenyl groups in the title molecule are nearly perpendicular to that of the pyridine ring. In the crystal, π-stacking and C—H···O hydrogen bond interactions involving the pyridine ring and the nitrile group of an adjacent molecule form the full 3-D structure. Hirshfeld surface (HS) analysis shows the topology of the molecules in the crystal packing. Fingerprint (FP) diagrams show the percentage contribution of several intermolecular interactions where H‧‧‧H interactions have a significant contribution (46%). The DFT study reveals a low HOMO-LUMO gap and significant charge transfer is indicated by the natural bonding orbitals (NBO) and frontier molecular orbital (FMO) analyses. Non-covalent interactions and bond characteristics were investigated using the quantum theory of atom in the molecule (QTAIM) and ELF analysis. FMO analysis was used to calculate the HOMO-LUMO energy gap and orbital energies. Using the DFT method, parameters such as global reactivity were calculated. Using the implicit solvent model, properties such as optical and nonlinear optical (NLO) were characterized in the solvent (water) phase and gas phase. The affinity of the title molecule for Monoamine Oxidase B was examined using molecular docking and molecular dynamics studies and these results showed good binding of the target molecule.

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.