Cyanide Research Articles

Attraction between Like Charged Ions in Ionic Liquids: Unveiling the Enigma of Tetracyanoborate Anions.

Intermolecular interactions in ionic liquids are mainly governed by Coulombic forces. Attraction between cations has been previously observed and was attributed to dispersion interactions between nonpolar moieties, hydrogen bonding, or π stacking. In this study, we present the intriguing behavior of tetracyanoborate anions in ionic liquids that, unlike their dicyanamide and tricyanomethanide counterparts, form dimers in both solid and liquid phases. A joint simulation and experimental study uncovers the origin of such anion-anion attraction: stabilization by induction and dispersion forces between several cyano groups, which is strong enough to overcome electrostatic repulsion. These findings open up new opportunities in the rational design of ionic liquids, where interactions between ions of the same charge can be controlled and fine-tuned by the presence of cyano groups.

Dicyanostilbene‐Derived Highly Sensitive Two‐Photon Fluorescence Temperature Probe for Live Cell Imaging

AbstractA novel two‐photon fluorescence temperature‐sensitive probe (SP) with the push‐pull electronic architecture (Donor‐π‐Acceptor, D‐π‐A) derived from dicyanostilbene was developed. Its linearly dependent coefficients (R2) between the emission intensity of SP and temperature reached 0.998 and 0.999 in one‐ and two‐photon fluorescence (OPF and TPF), respectively, and corresponding function expressions were IF=−0.0144T+1.2751 (OPF) and IF=−0.0152T+1.2970 (TPF). Its maximum two‐photon excitation wavelength (λmax2) is 750 nm, and the corresponding maximum two‐photon absorption cross‐section (δmax) is 1550 GM. DFT (Density Functional Theory) Calculation demonstrated that the electron cloud densities of two nitrogen atoms (N29 and N31) on two cyano groups are 15.9 and 16.0 times higher than that of nitrogen atom on 9‐carbazolyl group (N13), respectively. This fully indicates that the electron cloud of nitrogen atom on 9‐carbazolyl group is highly delocalized to the fluorophore matrix. SP can be used for live cell imaging and detect cell temperature to diagnose disease within physiological temperature range with excellent photostability and without cytotoxicity.

Selective sensing of cyanide ions: impact of molecular design and assembly on the response of π-conjugated acylhydrazone compounds.

This study investigates the sensing properties of two distinct compounds, denoted as 1 and 2, featuring acylhydrazone units. Spectroscopic analyses reveal the disruption of the supramolecular assembly upon binding with cyanide ions, consequently due to the hydrogen bonding interaction with acylhydrazone units. This leads to a ratiometric, color-changing response of both the compounds specifically towards cyanide ions. The investigation sheds light on the reversible nature of the cyanide-probe interaction and highlights the potential for reusability in cyanide ion detection. Moreover, compound 1, distinguished by its long alkyl chains, displays a superior response to CN- ions (∼4-fold larger signal), in contrast to compound 2. However, interference was observed from other basic anions, such as F- and AcO-. The research suggests the dominating role of supramolecular assembly, intermolecular interaction, and local hydrophobic environment around the binding sites on the analytical performance of the probe molecules. The findings underscore the significance of structural design and molecular assembly in dictating the selectivity and sensitivity of compounds, offering valuable insights for the development of efficient sensor systems in diverse real-world applications.

The half-life of cyanide in the blood of the marine fish, Amphiprion clarkii after cyanide exposure

Cyanide fishing continues to be used in the Indo-Pacific region to capture live reef fish for use by the live fish food and marine aquarium trades. The deliberate release of this broad-spectrum poison in reef environments is one of many anthropogenic threats to coral reefs today. Although this capture method is illegal in most countries, regulating its use is challenging due to the difficulty in determining whether a fish was captured using cyanide. A reliable method to test if marine fish have been caught using cyanide has long been the goal of the marine aquarium trade, but to date no test has been validated on fish with known cyanide (CN) exposure. Additionally, there are little to no toxicokinetic data on CN metabolism following CN exposure for marine fish. In this study, we exposed 38 specimens of Amphiprion clarkii to cyanide (50 ppm for 45 s) and measured the concentration of cyanide in their blood over time to characterize the detoxification process. CN was isolated from the blood by microdiffusion and derivatized to the highly fluorescent ẞ-isoindole and then quantified by HPLC. The half-life of cyanide in the blood of the marine fish A. clarkii was found to be 3.1 ± 2.0 hrs. CN levels were seen to be slightly above control levels 1 day post exposure and below control levels 3 days post exposure suggesting that any test for CN exposure by measuring cyanide must be conducted soon after exposure. To our knowledge, this is the first direct measurement of cyanide in the blood of a marine fish following CN exposure.

Efficient synthesis of α-amino-vinylphosphine oxides from alkyl nitriles via manganese-catalyzed phosphinoenamination.

A protocol for the synthesis of α-amino-vinylphosphine oxides by phosphinoenamination reaction between alkyl nitriles and phosphine oxides was developed. The combination of Mn(OAc)2 as a Lewis acid and guanidine as a Lewis base was found to be an efficient catalytic system for this reaction. A series of alkyl nitriles and phosphine oxides are compatible with this conversion, furnishing the desired products in up to 95% yield under mild conditions. Furthermore, this method demonstrates the capability of gram-scale synthesis.

Au nanoparticle-catalyzed double hydrosilylation of nitriles by diethylsilane.

We present the first example of Au-catalyzed reduction of nitriles into primary amines. In contrast to monohydrosilanes which are completely unreactive, diethylsilane (a dihydrosilane) is capable of reducing aryl or alkyl nitriles into primary amines under catalysis by Au nanoparticles supported on TiO2, via a smooth double hydrosilylation pathway. The produced labile N-disilylamines are readily deprotected by HCl in Et2O to form the hydrochloric salts of the corresponding amines in very good to excellent yields. The catalyst is recyclable and reusable at least in 5 consecutive runs.

Ambipolar conjugated ladder polymers by room-temperature Knoevenagel polymerization.

Two soluble conjugated ladder polymers (cLPs), decorated with multiple electron-poor species (i.e., cyano groups, fused pentagons, and N-heterocyclic rings), have been synthesized from the newly developed tetraketo-functionalized double aza[5]helicene building blocks using a single-step Knoevenagel polycondensation strategy. This facile approach features mild conditions (e.g., room temperature) and high efficiency, allowing us to quickly access a nonalternant ladder-like conjugated system with the in situ formation of multicyano substituents in the backbone. Analysis by 1H NMR, FT-Raman, and FT-IR spectra confirms the successful synthesis of the resulting cLPs. The combination of theoretical calculations and experimental characterizations reveals that the slightly contorted geometry coupled with a random assignment of trans- and cis-isomeric repeating units in each main chain contributes to improving the solubility of such rigid, multicyano nanoribbon systems. Apart from outstanding thermal stability, the resulting cLPs exhibit attractive red fluorescence, excellent redox properties, and strong π-π interactions coupled with orderly face-on packing in their thin-film states. They are proven to be the first example of ambipolar cLPs that show satisfactory hole and electron mobilities of up to 0.01 and 0.01 cm2 V-1 s-1, respectively. As we demonstrate, the Knoevenagel polycondensation chemistries open a new window to create complex and unique ladder-like nanoribbon systems under mild reaction conditions that are otherwise challenging to achieve.

Silver ion-regulated reliable and rapid detection technique for alkaline phosphatase based on surface-enhanced Raman spectroscopy.

The primary characteristics of a clinical assay are its accuracy and speed. For alkaline phosphatase (ALP) monitoring in medical treatment, a rapid, reliable surface-enhanced Raman scattering (SERS) detection technique was designed based on the controlled "hot spot" effect caused by the mediation of silver ions (Ag+). Consisting of functionalized Au nanoparticles (NPs), Ag+, and the enzyme substrate 2-phospho-L-ascorbic acid triso-dium salt (AAP), the fabricated detection technique can achieve a reliable clinical assay for ALP detection in human serum within several minutes. Herein, due to the coordination interaction of Ag+ and the cyano group (-CN), Ag+ can coordinate with p-mercaptobenzonitrile (MBN) modified on the surface of Au NPs, leading to the connection of adjacent Au NPs in a controllable manner to form a chain structure, in which the SERS signal of MBN at 2228 cm-1 in the Raman silent region would be highly amplified. Under the enzymatic biocatalysis of ALP, AAP was converted into ascorbic acid (AA). AA triggered the reduction of Ag+ into Ag0, resulting in a decrease in the concentration of Ag+. Meanwhile, the decrease in the SERS intensity of MBN was well-controlled and was recognized with the increased amounts of ALP. Based on this, the SERS detection technique for ALP was established. The limit of detection (LOD) for the detection of ALP was as low as 1.23 pg mL-1 (0.005 U L-1). Because of all these characteristics and its ultrahigh stability, this SERS detection technique is an important point-of-care candidate for the reliable, efficacious, and highly sensitive detection of ALP.

Peroxodisulfate-assisted synthesis of 2-thiocyanato glycals and their transformation to C-2-thio acrylo/aryl nitrile-substituted glycals.

An efficient regioselective method to attach thiocyanato groups at the β-position of enol double bonds in sugar enol ethers using KSCN and potassium persulfate has been developed. The highly regioselective addition of the resulting sugar thiocyanate to electron rich species like terminal alkynes and benzynes under Pd catalysis generated C-2-thio acrylo/aryl nitrile glycals via simultaneous introduction of thio and cyano groups into carbon-carbon triple bonds.

Cyano modified triphenylmethyl radical skeletons: higher stability and efficiency.

We introduced cyano groups to replace chlorine atoms in the tris(2,4,6-trichlorophenyl)methyl (TTM) radical skeleton, resulting in two cyano-modified TTM skeletons. The incorporation of cyano groups effectively suppresses nonradiative transition processes and lowers the frontier molecular orbital energy levels compared to those of the TTM radical. Consequently, enhanced photoluminescence quantum efficiency (PLQE) and a shift towards longer-wavelength emission in solution were achieved. Furthermore, the cyano-modified TTM skeletons exhibited improved stabilities. The development of these two skeletons adds diversity to stable organic luminescent radical skeletons.

Access to cyclohexadiene and benzofuran derivatives via catalytic arene cyclopropanation of α-cyanodiazocarbonyl compounds.

The arene cyclopropanation between diazo compounds and benzene is well known to produce a tautomeric mixture of norcaradiene and cycloheptatriene in favour of the latter species. Nevertheless, previous studies have suggested that the initially formed norcaradiene can be stabilized by a C-7 cyano group with prevention of its 6π-electrocyclic ring opening. According to this feature, a synthetic route to functionalized cyclohexadienes has been designed using α-cyanodiazoacetates and α-diazo-β-ketonitriles as the starting materials, respectively. The Rh2(esp)2-catalyzed arene cyclopropanation of α-cyanodiazoacetates in benzene afforded the expected 7-alkoxycarbonyl-7-cyanonorcaradienes as isolable compounds, which then served as templates for the second cyclopropanation with ethyl diazoacetate or α-cyanodiazocarbonyls to enable the formation of bis(cyclopropanated) adducts. Their subsequent treatment with SmI2 triggered a double ring-opening process, allowing for the generation of 1,4- and/or 1,3-cyclohexadienes as either regio- or diastereomeric mixtures. On the other hand, the norcaradienes generated from phenyl- or methyl-substituted α-diazo-β-ketonitriles were found to undergo an in situ rearrangement to yield dihydrobenzofurans that could be converted to benzofuran derivatives by DDQ oxidation.

Cyano-modified poly(triazine imide) with extended π-conjugation for photocatalytic biological cofactor regeneration

A unique extended π-conjugated system of cyano-modified PTI is strategically developed for biological cofactor regeneration.

Direct transformation of nitriles to cyanide using chloride anion as catalyst.

A simple method is explored for the scission of C-CN bonds into aldehyde and CN- in air. The transformation was mediated by chloride anions. The cyanide anions were extracted from the reaction solution to form (Et4N)2[Zn(CN)4] and (Et4N)2[Ni(CN)4]. A chloride-induced reaction mechanism is proposed based on experimental studies and DFT calculations. This work might guide the study of halogen catalysts for C-C bond cleavage.

A reaction based carbazole-indolium conjugate probe for the selective detection of environmentally toxic ions.

A nucleophilic addition based chemodosimeter was designed and synthesized with a carbazole donor and an indole acceptor. The addition of a cyanide ion to an electron-deficient indole moiety disrupts the acceptor-donor relationship, resulting in noticeable color shifts and spectrum differences in both the absorption and emission profiles. The design has a D-π-A molecular arrangement. Selectivity was investigated in 90% aqueous DMSO solution of probe CI with various anions such as SCN-, PF6-, NO3-, N3-, I-, HSO4-, CN-, H2PO4-, F-, HS-, ClO4-, Cl-, Br-, and AcO-. An intermolecular charge transfer (ICT) band at 506 nm in the UV-visible spectra vanished and the intensity of emission was quenched at 624 nm upon the addition of CN- ions. These outcomes demonstrate the effective nucleophilic addition of cyanide ions to the electron-deficient indole moiety of the probe, resulting in the formation of a new adduct in which the ICT transition is interrupted when π conjugation is blocked. The Job plot, 1H NMR spectroscopy, and HRMS analysis confirmed the formation of a new product. An outstanding response was shown by paper test strips made using probe molecules for the easy detection of cyanide ions in aqueous solutions. Besides, the probe selectively senses cyanide ions in different water samples.

Excited-state symmetry breaking is an ultrasensitive tool for probing microscopic electric fields.

Microscopic electric fields are increasingly found to play a pivotal role in catalysis of enzymatic and chemical reactions. Currently, the vibrational Stark effect is the main experimental method used to measure them. Here, we demonstrate how excited-state symmetry breaking can serve as a much more sensitive tool to assess these fields. Using transient infrared spectroscopy on a quadrupolar probe equipped with nitrile groups we demonstrate both its superior sensitivity and that it does not suffer from the notorious hydrogen-bond induced upshift of the C[triple bond, length as m-dash]N stretch frequency. In combination with conventional ground-state infrared absorption, excited-state symmetry breaking can be used to disentangle even weak specific hydrogen bond interactions from general field effects. We showcase this capability with the example of weak C-H hydrogen bonds in polar aprotic solvents. Additionally, we reveal for the first time symmetry breaking driven not by solvent but by the entropy of the pendant side chains of the chromophore. Our findings not only enhance our understanding of symmetry-breaking charge-transfer phenomena but pave the way toward using them in electric field sensing modality.

An antiviral oligomerized linear thiopeptide with a nitrile group from soil-derived Streptomyces sp. CPCC 203702.

A new linear thiopeptide, bernitrilecin (1), was isolated from Streptomyces sp. CPCC 203702. Compound 1 is the first example of a nitrile-bearing thiopeptide. Its structure and absolute configuration were elucidated by extensive analysis of spectroscopic data and Marfey's method. The biosynthesis of the nitrile unit for 1 was proposed to be through oxidations, decarboxylation, and dehydration. Compound 1 exhibited significant anti-influenza A virus activity with the IC50 value of 16.7 μM.

Shortening CN⋯Br–Csp3 halogen bonds via π-stacking

An extremely short N⋯Br distance between a nitrile group and a Csp3-linked bromine atom was encountered in the solid-state and rationalized by DFT calculations, which emphasized the role of π-stacking for bringing both partners at close proximity.

Facile Synthesis of Electron-deficient Epoxides Adjacent to Ester and Cyanide Groups

Abstract: The addition of camphor and oxone® during the epoxidation led to the synthesis of seven novel epoxides. Since the tri-substituted double bond of -cyano-cinnamates has been epoxidized, the reaction is easier to carry out and cleaner, producing a high yield of epoxides. Several molecules with industrial applications will result from the selective ring opening of epoxides.

Electrochemical lithium storage of a biactive organic molecule containing cyano and imine groups.

With an electron-deficient rigid planar structure and excellent π-π stacking ability, hexaazatriphenylene (HAT) and its derivatives are widely used as basic building blocks for constructing covalent organic frameworks (COFs), components of organic light-emitting diodes and solar cells, and electrode materials for lithium-ion batteries (LIBs). Here, a HAT derivative, hexaazatriphenylenehexacarbonitrile, is explored as an anode material for LIBs. The HAT anode exhibited high initial reversible capacities of 672 mA h g-1 at 100 mA g-1 and 550 mA h g-1 at 400 mA g-1 and stable cycling with a capacity of 503 mA h g-1 after 1000 cycles at 400 mA g-1 corresponding to a capacity retention of 91.5%. Furthermore, the lithium storage mechanism and the cause of the first irreversible capacity loss of the HAT anode were investigated by X-ray photoelectron spectroscopy (XPS) analysis and density functional theory (DFT) calculations. We have carried out a series of analyses on the mechanism of initial capacity loss. This study provides new insight on initial capacity loss and provides valuable insights into the molecular design and the electrochemical properties of HAT-based anode materials.

Visible-light-induced C-H alkylation of 2-amino-1,4-naphthoquinones.

Simple and practical strategies for visible-light-induced C-H alkylation of 2-amino-1,4-naphthoquinones with cyclobutanone oxime esters and hydroxamic acid derivatives have been developed under mild and redox-neutral conditions. These two reactions can be carried out at room temperature and obtain a variety of 2-amino-1,4-naphthoquinone derivatives with cyano and amide groups. Moreover, the cyanoalkylation reaction of 2-amino-1,4-naphthoquinones can proceed smoothly in the absence of photocatalysts.