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Time-resolved studies using 100 fs laser pulses generate CN radicals photolytically in solution and probe their subsequent reaction with solvent molecules by monitoring both radical loss and product formation. The experiments follow the CN reactants by transient electronic spectroscopy at 400 nm and monitor the HCN products by transient vibrational spectroscopy near 3.07 μm. The observation that CN disappears more slowly than HCN appears shows that the two processes are decoupled kinetically and suggests that the CN radicals rapidly form two different types of complexes that have different reactivities. Electronic structure calculations find two bound complexes between CN and a typical solvent molecule (CH2Cl2) that are consistent with this picture. The more weakly bound complex is linear with CN bound to an H atom through the N atom, and the more strongly bound complex has a structure in which the CN bridges Cl and H atoms of the solvent. Fitting the transient absorption data with a kinetic model containing two uncoupled complexes reproduces the data for seven different chlorinated alkane solvents and yields rate constants for the reaction of each type of complex. Depending on the solvent, the linear complex reacts between 2.5 and 12 times faster than the bridging complex and is the primary source of the HCN reaction product. Increasing the Cl atom content of the solvents decreases the reaction rate for both complexes.

Rationale: Cystic fibrosis (CF) patients are known to produce cyanide (CN-) although challenges exist in determinations of total levels, the precise bioactive levels, and specificity of its production by CF microflora, especially P. aeruginosa. Our objective was to measure total CN- levels in CF sputa by a simple and novel technique in P. aeruginosa positive and negative adult patients, to review respiratory tract (RT) mechanisms for the production and degradation of CN-, and to interrogate sputa for post-translational protein modification by CN- metabolites. Methods: Sputa CN- concentrations were determined by using a commercially available CN- electrode, measuring levels before and after addition of cobinamide, a compound with extremely high affinity for CN-. Detection of protein carbamoylation was measured by Western blot. Measurements and main results: The commercial CN- electrode was found to overestimate CN- levels in CF sputum in a highly variable manner; cobinamide addition rectified this analytical issue. Although P. aeruginosa positive patients tended to have higher total CN- values, no significant differences in CN- levels were found between positive and negative sputa. The inflammatory oxidant hypochlorous acid (HOCl) was shown to rapidly decompose CN-, forming cyanogen chloride (CNCl) and the carbamoylating species cyanate (NCO-). Carbamoylated proteins were found in CF sputa, analogous to reported findings in asthma. Conclusions: Our studies indicate that CN- is a transient species in the inflamed CF airway due to multiple biosynthetic and metabolic processes. Stable metabolites of CN-, such as cyanate, or carbamoylated proteins, may be suitable biomarkers of overall CN- production in CF airways.

The quantitative photofragment fluorescence spectroscopy, using the synchrotron radiation as an exciting light source, was applied to study the Rydberg and high-lying valence states of ClCN observed as congested structures in the vacuum ultraviolet region. The absolute cross-section and quantum yield for the CN(B2Σ+-X 2Σ+) emission produced in the photodissociation process of ClCN were determined in the wavelength range 105-145 nm (69 000-95 200 cm-1). The quantum yield for the CN(B2Σ+) production takes a maximum value of ?0.13 at ?84 000 cm-1. The emission of CN(B 2Σ+-X2Σ+) transition was found to be partially polarized with respect to the direction of the electric vector of the excitation synchrotron radiation. The polarization anisotropy of this emission, which depends on the symmetry of absorption transitions into the photodissociative states of ClCN was measured as a function of exciting wavelength. The relative cross-section for the production of CN(A2Π(i)-X2Σ+) emission was also determined. Based on the measured photochemical properties of the high-energy electronic states, the observed bands of the Rydberg and intravalence transitions are assigned. (C) 2000 Elsevier Science B.V.

5-Chloro-1,2,3,4-thiatriazole has been investigated in the gas phase for the first time by mid-infrared and He I photoelectron spectroscopy. The ground-state geometry has been obtained from quantum chemical calculations at the CCSD(T) and B3LYP levels using aug-cc-pVTZ basis set. Ionization potentials have been determined and the electronic structure has been discussed within the frame of molecular orbital theory. IR and photoelectron spectroscopies, supported by quantum chemical calculations at the B3LYP and SAC-CI levels, provide a detailed investigation into the vibrational and electronic character of the molecule. Thermal stability of 5-chloro-1,2,3,4-thiatriazole has been studied both experimentally and theoretically. Flash vacuum thermolysis of the molecule produces fast quantitatively N2, ClCN, and sulfur. Theoretical calculations at the CCSD(T)//B3LYP level predict competitive decomposition routes, starting either with a retro-cycloaddition reaction leading to N2S and ClCN or with a ring opening to chlorothiocarbonyl azide intermediate, to produce finally N2, S, and ClCN. Calculations also predict that N2S is reactive and decomposes in bimolecular reactions to N2 and S2.

The adsorption and decomposition of cyanogen halides, XCN (X = Br, Cl), on Si(100) is investigated utilizing X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). For submonolayer exposures, XPS indicates that the CN triple bond of XCN remains intact upon adsorption at 100 K. The UPS spectrum contains two peaks assigned to the π-electrons in the CN triple bond. The splitting indicates that some fraction of the XCN molecules adsorbs molecularly at low temperature. XPS analyses of the C 1s photoelectron peak following submonolayer exposure at low temperature suggest a greater fraction of BrCN (60%) adsorbs molecularly than ClCN (40%). XPS and UPS measurements at room temperature show that the X-CN bond breaks, while the CN bond remains intact during room-temperature adsorption on Si(100). Thus, the UPS spectrum of XCN adsorbed at room temperature on Si(100) contains a peak at 6.0 eV due to the unperturbed π electrons of the CN species. Upon annealing a CN-saturated Si(100) surface to higher temperatures, the UPS spectra indicate that the CN bond remains intact until approximately 700 K. Simultaneous changes in the C 1s and N 1s photoelectron peaks are consistent with the idea that CN bond cleavage is correlated with silicon carbide and nitride formation. These results are compared with a previous study of ICN adsorption on Si(100).

An operationally simple oxidation-cyanation method for the synthesis of cyanamides is described. The procedure utilizes inexpensive and commercially available N-chlorosuccinimide and Zn(CN)2 as reagents to avoid direct handling of toxic cyanogen halides. It is demonstrated to be amenable for the cyanation of a variety of primary and secondary amines and aniline derivatives as well as a complex synthetic intermediate en route to verubecestat (MK-8931). Additionally, kinetic measurements and other control experiments are reported to shed light onto the mechanism of this cyanation reaction.

A method for efficiently producing a cyanogen halide with suppressed side effects, and a method for producing a high-purity cyanate ester compound at a high yield includes contacting a halogen molecule with an aqueous solution containing hydrogen cyanide and/or a metal cyanide, so that the hydrogen cyanide and/or the metal cyanide is allowed to react with the halogen molecule in the reaction solution to obtain the cyanogen halide, wherein more than 1 mole of the hydrogen cyanide or the metal cyanide is used based on 1 mole of the halogen molecule, and when an amount of substance of an unreacted hydrogen cyanide or an unreacted metal cyanide is defined as mole (A) and an amount of substance of the generated cyanogen halide is defined as mole (B), the reaction is terminated in a state in which (A):(A)+(B) is between 0.00009:1 and 0.2:1.

The photolysis of four chloro-substituted thiadiazoles (3,4-dichloro-, 3-chloro-and 3-chloro-4-fluoro-1,2,5-thiadiazole; 3,5-dichloro-1,2,4- thiadiazole) and 3,4-dicyano-1,2,5-thiadiazole was investigated in inert solid-argon matrices at cryogenic tempera

The kinetics of reactions of CN with the chlorinated methanes CH3Cl, CH2Cl2, CHCl3 and CCl4 were investigated over the temperature range 298-573 K, using laser induced fluorescence (LIF) spectroscopy. At 298 K, rate constants of 9.0 ± 0.3 × 10-13, 8.8 ± 0.4 × 10-13, 9.0 ± 0.5 × 10-13 and 4.3 ± 0.6 × 10-13 cm3 molecule-1 s-1 were measured, respectively. A small positive temperature dependence was observed, as well as kinetic isotope effects of kH/kD ～ 2.14-2.25. These data along with product detection experiments strongly suggest that hydrogen abstraction dominates these reactions.

The gas-phase generation and spectroscopic identification of nitrile sulfides by thermolysis of 1,2,5-thiadiazole precursors was attempted, but in all cases the thiadiazoles were found to produce sulfur and the corresponding nitrile. This prompted an investigation by ab initio and density functional calculations for the equilibrium geometries, stabilities, and decomposition mechanisms of several nitrile sulfides (XCNS, where X = H, F, Cl, CN, CH3). Equilibrium geometries obtained from calculations at the B3LYP, MPn(n = 2-4), QCISD, QCISD(T), CCSD, and CCSD(T) levels with moderate to large basis sets indicate that the molecules have linear heavy atom geometries. The exception is the fluoro derivative, which is bent with a calculated barrier to linearity of 889 cm-1 (B3LYP/cc-pVTZ). The nitrile sulfides are predicted by the B3LYP method to be stable in the dilute gas phase, whereas in the condensed phase they are suggested to be very unstable due to bimolecular decomposition. The mechanism of this loss process is complicated by various sulfur transfer and cyclization reactions between decomposition intermediates, with the predicted stable products being sulfur, nitriles, and thiadiazoles. The first step of the bimolecular decomposition is either a cycloaddition to thiofuroxan or a sulfur transfer with simultaneous S2 loss to nitriles.

Aqueous solutions containing six model organic-N compounds (glycine, cysteine, asparagine, uracil, cytosine, and guanine) were subjected to chlorination at various chlorine (CI) to precursor (P) molar ratios for 30 min. Chlorine residuals were determined by both DPD/FAS titration and the MIMS (Membrane Introduction Mass Spectrometry) method to evaluate breakpoint chlorination behavior, residual chlorine distributions, and byproducts. DPD/FAS titration was found to yield false-positive measurements of inorganic combined chlorine residuals in all cases. The breakpoint chlorination curve shape was strongly influenced by the structure of the model compound. Cyanogen chloride was found to be present as a byproduct in all cases, and the yield was strongly dependent on the CI:P molar ratio and the structure of the compounds, with glycine being the most efficient CNCI precursor. Six byproducts other than cyanogen chloride were also identified. Free chlorine measurements by DPD/FAS titration and MIMS were in good agreement. This finding, together with the results of previously conducted research, suggests that both methods are capable of yielding accurate measurements of free chlorine concentration, even in solutions that contain complex mixtures of +1-valent chlorine compounds. Aqueous solutions containing six model organic-N compounds (glycine, cysteine, asparagine, uracil, cytosine, and guanine) were subjected to chlorination at various chlorine (Cl) to precursor (P) molar ratios for 30 min. Chlorine residuals were determined by both DPD/FAS titration and the MIMS (Membrane Introduction Mass Spectrometry) method to evaluate breakpoint chlorination behavior, residual chlorine distributions, and byproducts. DPD/FAS titration was found to yield false-positive measurements of inorganic combined chlorine residuals in all cases. The breakpoint chlorination curve shape was strongly influenced by the structure of the model compound. Cyanogen chloride was found to be present as a byproduct in all cases, and the yield was strongly dependent on the Cl:P molar ratio and the structure of the compounds, with glycine being the most efficient CNCl precursor. Six byproducts other than cyanogen chloride were also identified. Free chlorine measurements by DPD/FAS titration and MIMS were in good agreement. This finding, together with the results of previously conducted research, suggests that both methods are capable of yielding accurate measurements of free chlorine concentration, even in solutions that contain complex mixtures of +1-valent chlorine compounds.

Methanediol dehydrates to give formaldehyde, which reacts rapidly and reversibly with monochloramine to form N-chloroaminomethanol. Under drinking water conditions, N-chloroaminomethanol undergoes a relatively slow decomposition that eventually leads to the formation of cyanogen chloride (ClCN) in apparently stoichiometric amounts. The following reaction sequence is proposed: CH2(OH)2 ? CH2O + H2O; CH2O + NH2Cl ? CH2(OH)NHCl; CH2(OH)NHCl → CH2NCl + H2O; CH2NCl → HCl + HCN; CN- + NH2Cl + H+ → ClCN + NH3. These reactions were studied at 25.0°C and an ionic strength of 0.10 M (NaClO4). Stopped-flow photometry was used to monitor rapid, reversible reactions, and photometry was used to study relatively slow decomposition reactions. Equilibrium and rate constants for the addition of formaldehyde to monochloramine were (6.6 ± 1.5) x 105 M-1 and (2.8 ± 0.1) x 104 M-1 s-1, respectively. The dehydration of N- chloroaminomethanol was catalyzed by both H+ and OH-, with respective rate constants of 277 ± 7 and 26.9 ± 5.6 M-1 s-1. Under characteristic drinking water conditions, the decay of N-chloroaminomethanol is the rate- limiting step. N-Chloromethanimine, formed by the dehydration of N- chloroaminomethanol, had a decomposition rate constant of (6.65 ± 0.06) x 10-4 s-1. At the relatively high methanediol concentrations used in this study, the intermediary N-chlorodimethanolamine was formed by the rapid and reversible reaction of N-chloroaminomethanol with formaldehyde. N- Chlorodimethanolamine then decayed relatively slowly. The following reaction sequence is proposed: CH2(OH)NHCl + CH2O ? {CH2(OH)}2NCl; {CH2(OH)}2NCl → CH2NCl + CH2O + H2O. The equilibrium and rate constants for the addition of formaldehyde to N-chloroaminomethanol were (9.5 ± 2.5) x 104 M-1 and (3.6 ± 0.1) x 103 M-1 s-1, respectively. The decomposition of N-chlorodimethanolamine was catalyzed by OH-, with a rate constant of 19.2 ± 3.7 M-1 s-1. N-Chlorodimethanolamine would not be present under typical drinking water treatment conditions. Methanediol dehydrates to give formaldehyde, which reacts rapidly and reversibly with monochloramine to form N-chloroaminomethanol. Under drinking water conditions, N-chloroaminomethanol undergoes a relatively slow decomposition that eventually leads to the formation of cyanogen chloride (ClCN) in apparently stoichiometric amounts. The following reaction sequence is proposed: CH2(OH)2qqCH2O+H2O; CH2O+NH2ClqqCH2(OH)NHCl; CH2(OH)NHCl→CH2NCl+H2O; CH2NCl→HCl+HCN; CN-+NH2Cl+H+→ClCN+NH3. These reactions were studied at 25.0 °C and an ionic strength of 0.10 M (NaClO4). Stopped-flow photometry was used to monitor rapid, reversible reactions, and photometry was used to study relatively slow decomposition reactions. Equilibrium and rate constants for the addition of formaldehyde to monochloramine were (6.6±1.5)×105 M-1 and (2.8±0.1)×104 M-1 s-1, respectively. The dehydration of N-chloroaminomethanol was catalyzed by both H+ and OH-, with respective rate constants of 277±7 and 26.9±5.6 M-1 s-1. Under characteristic drinking water conditions, the decay of N-chloroaminomethanol is the rate-limiting step. N-Chloromethanimine, formed by the dehydration of N-chloroaminomethanol, had a decomposition rate constant of (6.65±0.06)×10-4 s-1. At the relatively high methanediol concentrations used in this study, the intermediary N-chlorodimethanolamine was formed by the rapid and reversible reaction of N-chloroaminomethanol with formaldehyde. N-Chlorodimethanolamine then decayed relatively slowly. The following reaction sequence is proposed: CH2(OH)NHCl+CH2Oqq{CH2(OH)}2NCl; {CH2(OH)}2NCl→CH2NCl+CH2O+H2O. The equilibrium and rate constants for the addition of formaldehyde to N-chloroaminomethanol were (9.5±2.5)×104 M-1 and (3.6±0.1)×103 M-1 s-1, respectively. The decomposition of N-chlorodimethanolamine was catalyzed by OH-, with a rate constant of 19.2±3.7 M-1 s-1. N-Chlorodimethanolamine would not be present under typical drinking water treatment conditions.

Ground-state (N(S4)) nitrogen reactions with chloroform-h and chloroform-d were studied by using the VLPR technique at room temperature.Relative N atom concentrations were monitored via mass spectrometry, and their absolute values were determined by the chemical titration reaction with nitric oxide.It was possible to obtain a more accurate rate constant for the bimolecular reaction: N + NO ---> N2 + O, kNO = (2.4 +/- 0.2) x 10-11 cm3 molecule-1 s-1 at298 K.N atom decay in the presence of CHCl3 and CDCl3 was found to have an apparent induction period and to have a large isotope effect.Chemiluminescence signals emitted from the reactor in the range 300-600 nm were also observed, and identified as coming from the excited CN radical.The detailed study of reaction products, intermediates, N atom decay kinetics, and chemiluminescence signals are interpreted by slow reaction of Cl atoms with CHCl3 followed by fast branching chain reactions of N atoms with the intermediate radicals.A successful numerical simulation of the experimental results supports the suggested chain branching mechanism.The following rate constants were estimated from the experimental results: k1(N + CHCl3 ---> NCl + CHCl2), 1.00 x 10-16, k2(N + NCl ---> N + Cl), 2.57 x 10-11, k3(Cl + CHCl3 ---> HCl + CCl3), 3.70 x 10-14, k3D(Cl + CDCl3 ---> DCl + CCl3),0.95 x 10-14, k4(N + CHCl2 ---> HCN + 2Cl), 1.98 x 10-11, k5(N + CCl3 ---> ClCN + 2Cl), 1.67 x 10-11, k6(N + ClCN ---> CCl + N2), 1.00 x 10-14, and k7(N + CCl ---> CN(B2Σu+) + Cl), 5.70 x 10-13, all in the units of cm3 molecule-1 s-1.

The rate expression for OCl- oxidation of CN- is -d[OCl-]/dt = (k1 + k2/[OH-])[CN-][OCl-], where k1 is 310 M-1 s-1 and k2 is 583 s-1 (25.0°C, μ = 1.00 M). The observed inverse [OH-] dependence is due to the great reactivity of HOCl, which is 3.9 × 106 times more reactive than OCl- with CN-. The proposed mechanism with HOCl is OCl- + H2O ?k-3k3 HOCl + OH- HOCl + CN- →k4 CNCl + OH- CNCl + 2OH- → OCN- + Cl- + H2O where k4 is 1.22 × 109 M-1 s-1, on the basis of pKa = 7.47 for HOCl at μ = 1.00 M, 25.0°C. At high CN- concentration the HOCl reaction becomes so fast that proton-transfer reactions from H2O to OCl- and from HCN to OCl- OCl- + HCN ?k-5k5 HOCl + CN- contribute to the rate, where the values for k3 and k-3 are 9 × 103 s-1 and 1.9 × 1010 M-1 s-1 and the values for k5 and k-5 are 2.2 × 107 M-1 s-1 and 6.6 × 108 M-1 s-1. Rate constants for Cl+ transfer from HOCl to nucleophiles decrease in value by 10 orders of magnitude with CN- ≥ SO32- > I- ? Br- ? Cl-, in accord with the decrease of anion nucleophilicity.

Reactions of TeF5Cl with the nitrogen nucleophiles LiN=C(CF3)2, ((CH3)3Si)2NH, and (CH3)3SiNR2, where R=CH3, C2H5, result in the reduction of the tellurium to Te(IV) and chlorination of the respective nucleophile.Analogous results are obtained in the reaction of TeF5Cl with (CH3)3SiCN, C6F5Li, and C6F5SLi.In the case of (CH3)3SiNR2, the new adducts (TeF4)2*NR2Cl are obtained in high yield.These compounds have been identified through their infrared, 1H, 19F, and 125Te NMR, and mass spectra as well as by elemental analysis.

A systematic search for the unknown molecule selenoformaldehyde, H2C=Se, starts with the precalculation of its ionization pattern from ab-initio-PNO-CI and CEPA wave functions.The selenium precursors H3CSeSeCH3, H3CSeCN, H3CSeCl, and (H2CSe)3 are pyrolyzed in a flow system under PE spectroscopic real-time analysis: Applying "computerized spectra stripping" to the PE spectra of the pyrolysis mixtures, an ionization pattern can be extracted which correlates satisfactorily with the quantum chemical prediction for H2C=Se.To further support the assignment, selenoacetaldehyde, CH3CH=Se, and selenocarbonyl difluoride, F2C=Se, are prepared by thermal monomerization of 3 and (F2CSe)2, respectively.

Cyanogen chloride was formed by the reactions of aromatic amino acids such as phenylalanine, tyrosine, tryptophan and histidine with hypochlorous acid in the presence of ammonium ion.It was found that the formation of cyanogen chloride was due to cleavage of the aromatic rings of the aromatic amino acids by chloramine.Keywords - cyanogen chloride; chloramine; aromatic amino acid; ammonium ion; hypochlorous acid

A moderately stable hexacoordinated sulfur(VI) compound with four different kinds of ligands, CF3SF2(CN)2Cl, results when CF3SF4Cl is reacted with (CH3)3SiCN.The latter compound also gives F2S(CN)2 and (CF3)2S(CN)2 with SF4 and (CF3)2SF2, respectively.These tetracoordinated sulfur(IV) compounds decompose rapidly at 25 deg C but are stable at lower temperatures.With OSCl2 and SCl2, the white solids OS(CN)2 and S(CN)2 result.This provides a new, convenient route to S(CN)2. - Keywords: (Trifluoromethyl)chlorodicyanodifluorosulfur(VI), Dicyanodifluorosulfur(IV), Dicyanobis(trifluormethyl)sulfur(IV), Thionyl Cyanide

Treatment of perfluoro-2-azapropene with bis(bistrifluoromethylamino-oxy)mercury(II) yields the new mercurial (CF3)N>2Hg (11), chlorinolysis of which provides the N-chloroamine CF3NClCF2ON(CF3)2 (16); pyrolysis of the mercurial (11) gives a complex mixture containing the imine CF3N=CFON(CF3)2 (12) and material tentatively identified as >2O.The N-chloro-compound (16) reacts with hydrogen chloride and silver cyanide to provide the corresponding amine CF3NHCF2ON(CF3)2 and the related imine (12).The latter product, together with the di-substituted analogue (CF3)2NCF2N=CFON(CF3)2, can also be procured by treating perfluoro-2-azapropene with a caesium fluoride-NN-bistrifluoromethylhydroxylamine adduct.This reagent also attacks perfluoro-1-azacyclohexene to yield perfluoro- and perfluoro-, and similarly effects nucleophilic substitution in pentafluoropyridine to provide 4-(bistrifluoromethylamino-oxy)-2,3,5,6-tetrafluoropyridine.The mercurial 2Hg attacks the alkyliminocarbonyl chloride Me3CN=CCl2 to give the bistrifluoromethylamino-oxy-derivatives Me3CN=CCl and Me3CN=C2.

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