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Cyanide
Kinds of Cyanide Terms modified by Cyanide Selected AbstractsIntegration of continuous-flow sampling with microchip electrophoresis using poly(dimethylsiloxane)-based valves in a reversibly sealed deviceELECTROPHORESIS, Issue 14 2007Michelle W. Li Abstract Here we describe a reversibly sealed microchip device that incorporates poly(dimethylsiloxane) (PDMS)-based valves for the rapid injection of analytes from a continuously flowing stream into a channel network for analysis with microchip electrophoresis. The microchip was reversibly sealed to a PDMS-coated glass substrate and microbore tubing was used for the introduction of gas and fluids to the microchip device. Two pneumatic valves were incorporated into the design and actuated on the order of hundreds of milliseconds, allowing analyte from a continuously flowing sampling stream to be injected into an electrophoresis separation channel. The device was characterized in terms of the valve actuation time and pushback voltage. It was also found that the addition of sodium dodecyl sulfate (SDS) to the buffer system greatly increased the reproducibility of the injection scheme and enabled the analysis of amino acids derivatized with naphthalene-2,3-dicarboxaldehyde/cyanide. Results from continuous injections of a 0.39,nL fluorescein plug into the optimized system showed that the injection process was reproducible (RSD of 0.7%, n,=,10). Studies also showed that the device was capable of monitoring off-chip changes in concentration with a device lag time of 90,s. Finally, the ability of the device to rapidly monitor on-chip concentration changes was demonstrated by continually sampling from an analyte plug that was derivatized upstream from the electrophoresis/continuous flow interface. A reversibly sealed device of this type will be useful for the continuous monitoring and analysis of processes that occur either off-chip (such as microdialysis sampling) or on-chip from other integrated functions. [source] Ligand-Exchange Processes on Solvated Lithium Cations: Acetonitrile and Hydrogen Cyanide,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2007Ewa Pasgreta Abstract Solutions of LiClO4 in solvent mixtures of acetonitrile and water, or acetonitrile and nitromethane, were studied by 7Li NMR spectroscopy. Measured chemical shifts indicate that the Li+ cation is coordinated by four acetonitrile molecules. In the binary water/acetonitrile mixture, water coordinates more strongly to Li+ than acetonitrile such that addition of water immediately leads to the formation of [Li(H2O)4]+. The solvent-exchange mechanism for [Li(L)4]+ (L = CH3CN and HCN) was studied by using DFT calculations (RB3LYP/6-311+G**). This process was found to follow a limiting associative mechanism involving the formation of relatively stable five-coordinate intermediates. The suggested mechanisms are discussed with reference to available experimental and theoretical data. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synthesis of ,-Amino Nitriles from Carbonyl Compounds, Amines, and Trimethylsilyl Cyanide: Comparison between Catalyst-Free Conditions and the Presence of Tin Ion-Exchanged MontmorilloniteEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2010Jiacheng Wang Abstract In the absence of catalysts, the three-component, one-pot synthesis of ,-amino nitriles proceeded using various aldehydes and ketones together with amines and trimethylsilyl cyanide (TMSCN) in high yields under neat conditions at room temperature. The addition order of the reagents had a significant influence on the yields of the desired ,-amino nitriles. In contrast, when tin ion-exchanged montmorillonite (Sn-Mont), prepared by the ion-exchange of sodium montmorillonite (Na-Mont) with a tin tetrachloride solution, was used as a catalyst, the reaction rates significantly increased compared with those without catalysts, and the range of the applicable carbonyl compounds was also extended: structurally diverse aromatic, aliphatic and heteroatom-containing carbonyl compounds, including sterically hindered ketones as well as aliphatic and aromatic amines, were converted into the desired ,-amino nitriles in good to excellent yields with short reaction times under mild conditions. Sn-Mont showed a better catalytic activity than proton or other metal ion-exchanged montmorillonites, supported SnO2 catalysts and the previously reported homogeneous or heterogeneous catalysts. The recovered catalyst was reused several times without loss of catalytic performance. Along with the expansion of the interlayer space of Sn-Mont, the strong Brønsted acid and Lewis acid nature of Sn-Mont derived from protons and SnO2 nanoparticles present in the interlayers of Sn-Mont likely played important and cooperative roles in the high catalytic activity. [source] Gold-Nanocluster-Based Fluorescent Sensors for Highly Sensitive and Selective Detection of Cyanide in WaterADVANCED FUNCTIONAL MATERIALS, Issue 6 2010Yanlan Liu Abstract A novel, gold-nanocluster-based fluorescent sensor for cyanide in aqueous solution, which is based on the cyanide etching-induced fluorescence quenching of gold nanoclusters, is reported. In addition to offering high selectivity due to the unique Elsner reaction between cyanide and the gold atoms of gold nanoclusters, this facile, environmentally friendly and cost-effective method provides high sensitivity. With this sensor, the lowest concentration to quantify cyanide ions could be down to 200,×,10,9,M, which is approximately 14 times lower than the maximum level (2.7,×,10,6,M) of cyanide in drinking water permitted by the World Health Organization (WHO). Furthermore, several real water samples spiked with cyanide, including local groundwater, tap water, pond water, and lake water, are analyzed using the sensing system, and experimental results show that this fluorescent sensor exhibits excellent recoveries (over 93%). This gold-nanocluster-based fluorescent sensor could find applications in highly sensitive and selective detection of cyanide in food, soil, water, and biological samples. [source] Kinetics and Mechanism of the Demetallation of Macrocyclic Nickel(II) Complexes by CyanideHELVETICA CHIMICA ACTA, Issue 3 2005Liselotte Siegfried The kinetics and the mechanism of the cyanide-induced demetallation of a series of Ni2+ complexes with macrocyclic ligands of different ring size (12- to 14-membered; see 1,4) and steric constraints was studied. Although the rates differ by almost five orders of magnitude when compared to each other under fixed experimental conditions (pH,10.5, [CN,]=10,2,M), all reactions proceed through the relatively rapid formation of cyano adducts [Ni(CN)nL] (n=1, 2), which then react with additional CN, or HCN to give the final products. Of paramount importance for the reaction rate is the geometry and configuration of the cyano adducts [Ni(CN)nL] (n=1,2). cis -Dicyano derivatives with a folded macrocycle react faster than trans -compounds. In the case of (1,4,8,11-tetraazacyclotetradecane)nickel(2+) ([Ni (4)]2+), which gives a trans- dicyano adduct, the base-catalyzed N-inversion necessary to obtain the cis- dicyano derivative becomes rate determining at high CN, concentrations. [source] A Remarkable Titanium-Catalyzed Asymmetric Strecker Reaction using Hydrogen Cyanide at Room TemperatureADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2010Balamurugan Ramalingam Abstract Close to perfect enantioselectivity (up to 98% ee) is obtained for the formation of amino nitriles using hydrogen cyanide (HCN) as the cyanide source at room temperature for the first time. In an operationally simple process, the catalyst generated from a partially hydrolyzed titanium alkoxide (PHTA) and (S)- N -salicyl-,-amino alcohol ligand, catalyzes the cyanation of imines in a short reaction time. [source] Asymmetric meso -Epoxide Ring-Opening with Trimethylsilyl Cyanide Promoted by Chiral Binuclear Complexes of Titanium.ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009Dichotomy of CC versus CN Bond Formation Abstract In the presence of chiral catalysts derived from the same chiral hexadentate ligand and aluminium, zinc or titanium ions, the reaction between cyclohexene oxide and trimethylsilyl cyanide can be controlled to give predominantly either the nitrile (up to 99% ee) or the isonitrile product (up to 94% ee). The metal ion, ligand stereochemistry and base concentration all play a role in determining the product ratio. [source] Construction of Recombinant Escherichia coli Catalysts which Simultaneously Express an (S)-Oxynitrilase and Different Nitrilase Variants for the Synthesis of (S)-Mandelic Acid and (S)-Mandelic Amide from Benzaldehyde and CyanideADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009Olga Sosedov Abstract Recombinant Escherichia coli strains were constructed which simultaneously expressed the genes encoding the (S)-oxynitrilase from cassava (Manihot esculenta) together with the wild-type or a mutant variant of the arylacetonitrilase from Pseudomonas fluorescens EBC191 in a single organism under the control of a rhamnose-inducible promoter. The whole cell catalysts obtained converted benzaldehyde and potassium cyanide in aqueous media at pH,5.2 mainly to (S)-mandelic acid and/or (S)-mandelic amide and synthesized only low amounts of the corresponding (R)-enantiomers. The conversion of benzaldehyde and potassium cyanide (KCN) by a whole-cell catalyst simultaneously expressing the (S)-oxynitrilase and the wild-type nitrilase resulted in a ratio of (S)-mandelic acid to (S)-mandelic amide of about 4:3. This could be explained by the strong nitrile hydratase activity of the wild-type nitrilase with (S)-mandelonitrile as substrate. The relative proportion of (S)-mandelic amide formed in this system was significantly increased by coexpressing the (S)-oxynitrilase with a carboxy-terminally truncated variant of the nitrilase. This whole-cell catalyst converted benzaldehyde and KCN to mandelic amide and mandelic acid in a ratio of about 9:1. The ee of the (S)-mandelic amide formed was calculated to be >95%. [source] Molecular control of ethylene production by cyanide in Arabidopsis thalianaPHYSIOLOGIA PLANTARUM, Issue 2 2000Jennifer McMahon Smith Although cyanide has long been recognized as a co-product of ethylene synthesis, little attention has been given to its potential physiological and molecular roles. In the present work, the long-term effects of cyanide on growth and development were observed in Arabidopsis thaliana. Two days after a single 20-min application of cyanide, plants demonstrated visible signs of stress. Long-term detrimental effects on growth and photosynthetic capabilities were noted, including low chlorophyll accumulation and stunted growth. Because of the relationship between cyanide and ethylene production, we chose to evaluate the results of cyanide treatment on genes encoding proteins involved in ethylene synthesis. We have found that only the 1-aminocyclopropane-1-carboxylic acid (ACC) synthase gene, ACS6, is rapidly activated in response to cyanide treatment, while other ACS genes were unaffected. This same gene has previously been shown to be transcriptionally activated in response to touch and other environmental stimuli. Cyanide was capable of activating ACS6 transcription within 10 min of treatment, and the amount of transcript correlated positively with the cyanide dosage. Due to the toxic nature of cyanide, plant in vivo concentrations are generally maintained lower than 10 ,M, but can increase under certain stresses. In the present work, we observed that physiologically relevant concentrations as low as 1 ,M HCN, considered metabolically ,safe', were capable of initiating ACS6 transcription. ACS6 transcripts were not substantially reduced as a result of multiple cyanide treatments, which is in contrast with the effects of mechanical stimulation on transcription. Our results suggest a relationship between cyanide production during ethylene synthesis and the molecular control of ethylene synthesis. This work corresponds with earlier experiments that have demonstrated that ethylene and cyanide can elicit some similar physiological responses. It is possible that cyanide may play an active role in ethylene regulation under conditions where rapid cyanide accumulation occurs. Since cyanide can rapidly activate ethylene synthesis, it is possible that it is involved in the positive-feedback regulation of ethylene that occurs in some plant tissues. [source] Semi-quantitative tests of cyanide in foods and excreta of Three Hapalemur species in MadagascarAMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2010Nayuta Yamashita Abstract Three sympatric Hapalemur species (H. g. griseus, H. aureus, and H. (Prolemur) simus) in Ranomafana National Park, Madagascar are known to eat bamboo food parts that contain cyanide. How these lemurs avoid cyanide poisoning remains unknown. In this study, we tested for the presence/absence of cyanide in bamboo lemur foods and excreta to (1) document patterns of cyanide consumption among species with respect to diet, (2) identify routes of elimination of cyanide from the gastrointestinal tract, and (3) determine whether cyanide is absorbed from the diet. We tested 102 food, urine, and fecal samples for hydrogen cyanide (HCN) during two "pre-dry" seasons (April 2006, May 2007) using commercially available Cyantesmo test strips. The test strips changed color in the presence of HCN, and we recorded color change on a scale of 0 (no change) to 5 (cobalt) at preset intervals with a final score taken at 24,hr. We detected cyanide in bamboo food parts and urine of all three Hapalemur species. Time to color change of the test strips ranged from almost instantaneous to >12,hr incubation. Of the foods tested, only bamboo contained cyanide, but results differed among bamboo species and plant parts of the same species. Specifically, branch shoot and culm pith of the giant bamboo produced strong, immediate reactions to the test paper, whereas parts of liana bamboos produced either weak or no color change. Cyanide was present in almost all urine samples but rarely in fecal samples. This suggests that dietary cyanide is absorbed in the gastrointestinal tract of the Hapalemur species and excreted, at least in part, by the kidneys. Samples from H. griseus exhibited lower, though still detectable, cyanide levels compared with H. simus and H. aureus. Differences among lemur species appear to be related to the specific bamboo parts consumed. Am. J. Primatol. 72:56,61, 2010. © 2009 Wiley-Liss, Inc. [source] ChemInform Abstract: Palladium-Catalyzed Cyanation Reaction of Aryl Halides Using K4[Fe(CN)6] as Nontoxic Source of Cyanide under Microwave Irradiation.CHEMINFORM, Issue 43 2010Abdol R. Hajipour No abstract is available for this article. [source] ChemInform Abstract: One-Portion Synthesis of 2-Acetoxy Carbonyl Compounds from Aldehydes by Using an Acetylated Masked Acyl Cyanide.CHEMINFORM, Issue 38 2009Hisao Nemoto Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Direct Catalytic Asymmetric Addition of Allyl Cyanide to Ketones.CHEMINFORM, Issue 27 2009Ryo Yazaki Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: One-Pot Synthesis of ,-Siloxy Esters Using a Silylated Masked Acyl Cyanide.CHEMINFORM, Issue 14 2009Hisao Nemoto Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Synthesis of N-Allylideneamines and Their Use for the Double Nucleophilic Addition of Ketene Silyl (Thio)acetals and Trimethylsilyl Cyanide.CHEMINFORM, Issue 4 2009Isao Mizota Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Ruthenium-Catalyzed Oxidative Cyanation of Tertiary Amines with Molecular Oxygen or Hydrogen Peroxide and Sodium Cyanide: sp3 C,H Bond Activation and Carbon,Carbon Bond Formation.CHEMINFORM, Issue 51 2008Shun-Ichi Murahashi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Niobium(V) Chloride Catalyzed Synthesis of ,-Aminonitriles with Simultaneous Reaction of Aldehydes, Amines and Trimethylsilyl Cyanide.CHEMINFORM, Issue 47 2008Anjoy Majhi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Catalytic Enantioselective Conjugate Addition of Cyanide to Enones.CHEMINFORM, Issue 38 2008Yuta Tanaka Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Tetraaryl-1,3-dioxolane-4,5-dimethanols as Catalysts for the Addition of Trimethylsilyl Cyanide to Benzaldehyde and the Oxirane Ring.CHEMINFORM, Issue 22 2008Yu. N. Belokon Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Iodine-Catalyzed Three-Component Strecker-Type Synthesis of ,-Aminonitriles from Aldehydes, Amines and Tributyltin Cyanide.CHEMINFORM, Issue 23 2006Hong-She Wang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Asymmetric Addition of Trimethylsilyl Cyanide to Ketones Catalyzed by Al(salen)/triphenylphosphine Oxide.CHEMINFORM, Issue 17 2006Sung Soo Kim Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Ruthenium-Catalyzed Oxidative Cyanation of Tertiary Amines with Hydrogen Peroxide and Sodium Cyanide.CHEMINFORM, Issue 7 2006Shun-Ichi Murahashi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF. [source] Theoretical Investigations of Uranyl,Ligand Bonding: Four- and Five-Coordinate Uranyl Cyanide, Isocyanide, Carbonyl, and Hydroxide ComplexesCHEMINFORM, Issue 24 2005Jason L. Sonnenberg Abstract For Abstract see ChemInform Abstract in Full Text. [source] Enantioselective Addition of Trimethylsilyl Cyanide to Aldehydes Catalyzed by Bifunctional BINOLAM-AlCl versus Monofunctional BINOL-AlCl Complexes.CHEMINFORM, Issue 9 2005Jesus Casas Abstract For Abstract see ChemInform Abstract in Full Text. [source] Enantioselective Strecker Reactions Between Aldimines and Trimethylsilyl Cyanide Promoted by Chiral N,N,-Dioxides.CHEMINFORM, Issue 5 2004Zhigang Jiao Abstract For Abstract see ChemInform Abstract in Full Text. [source] Double Nucleophilic Addition of Ketene Silyl (Thio)acetals and Trimethylsilyl Cyanide to ,,,-Unsaturated Aldimines Promoted by Aluminum Chloride.CHEMINFORM, Issue 45 2003Makoto Shimizu Abstract For Abstract see ChemInform Abstract in Full Text. [source] Enzymatic Introduction of Cyanide into Imine for Constructing Optically Active Compound by (R)-Oxy-nitrilase in Almond Meal.CHEMINFORM, Issue 12 2003Teckheon Lee Abstract For Abstract see ChemInform Abstract in Full Text. [source] Toxicity Assessment of Cyanide and Tetramethylene Disulfotetramine (Tetramine) Using Luminescent Bacteria Vibrio-qinghaiensis and PbO2 Electrochemical SensorCHINESE JOURNAL OF CHEMISTRY, Issue 2 2007Wei Liu Abstract The toxicities of cyanide and tetramethylene disulfotetramine (tetramine) were evaluated by two methods of luminescent bacteria and PbO2 electrochemical sensor. Vibrio-qinghaiensis, a kind of luminescent bacteria, can produce bioluminescence and the bioluminescence was decreased with the addition of toxicants. The toxicities of cyanide and tetramine were expressed as 10 min-EC50 value, which was the concentration of chemical that reduces the light output by 50% after contact for 10 min. Nano PbO2 modified electrode, a rapid toxicity determination method was also described in this work. By the PbO2 modified electrode, the current responses of Escherichia coli (E. coli) were changed with the addition of toxicants. The value of 10 min-EC50 was also provided with the PbO2 electrochemical sensor. Compared with the 10 min-EC50 and detection limits (38.38 and 0.60 µg/mL for cyanide, 0.24 and 0.02 µg/mL for tetramine) with luminescent bacteria, the PbO2 sensor provided a simple and convenient method with lower 10 min-EC50 and detection limits (26.37 and 0.52 µg/mL for cyanide, 0.21 and 0.01 µg/mL for tetramine) and fast response time. [source] Synthesis and Structure Determination of Selenium(IV) CyanidesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 30 2008Stefanie Fritz Abstract The reaction of SeF4 with Me3SiCN did not result in thepreparation of the designated Se(CN)4 but Se(CN)F3 and Se(CN)2F2 were obtained as first known selenium(IV)cyanide compounds and characterized by their NMR spectra. Se(CN)2F2 was crystallized as 1,2-dimethoxyethane solvate as well as the corresponding tellurium compound Te(CN)2F2 with very similar structures. NMR spectroscopic data of some more miscellaneous tellurium cyanides and the crystal structures of solvates of Se(CN)2 and oxygen-bridged TeO(CN)2 are presented. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Chain-Like Tetra-, Penta- and Heptanuclear Cyanide-Bridged Complexes by Attachment of Organometallic Cyanides to M2, M3 and M5 UnitsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 20 2003Tianlu Sheng Abstract Attachment of the "ligands" [Cp(dppe)Fe-CN], [Cp(PPh3)2Ru-CN], [Cp(CO)2Fe-CN] and [(CO)5M-CN],, (where M = Cr, Mo, W) to the polymetallic centres [Ru2(OAc)4]+, [Co3(dpa)4]2+ and [Ni5(tdpa)4]2+ yielded two tetra-, three penta- and five heptanuclear complexes with chain-like linear arrangements of the metal ions and the bridging cyanide ligands, as proved by the structure determination of [Ni5(tdpa)4{Cp(dppe)2Fe-CN}2](PF6)2. IR and CV data show that the Ru2, Co3 and Ni5 centres of these complexes withdraw electron density from the external organometallic units. This prevents electronic interactions between the two terminal metal ions, yet allows multistep one- and two-electron redox processes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] | ||||||||||||||||||||||||||||||||||