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Infrared emission from the ν2 bending mode and ν3 C-H stretching mode of HCN have been observed following 193 nm pulsed excimer laser photolysis of 1,3,5-triazine.Using a simple harmonic oscillator analysis, the number of ν2 bending quanta produced in HCN from photolysis of sym-triazine was found to be 70 times larger than the number of ν3 C-H stretching quanta.The combination of a high density of bending vibrational states in HCN and favorable geometry changes which occur in going from 1,3,5-triazine to three HCN molecules, appear to give an unusually pure distribution which maximizes vibrational energy in the HCN bending mode.

UV photolysis of small molecules embedded in rare-gas matrices is examined. We demonstrate that photolysis can be self-limited when products absorb the photolysing radiation. As a result of the rising absorption, in-situ detected luminescence of the photolysis product saturates faster than its concentration. In particular, the present study supports the conclusion that 193 nm photolysis of hydrogen-containing species in Xe matrices produces hydrogen atoms in amounts comparable with the other dissociating part of the precursor. Also, we show that 193 nm radiation activates mobility of hydrogen atoms in annealing, accelerating photochemical processes related to hydrogen mobility.

The mechanism of Ni removal from Si O2 -covered Si specimens by HCN aqueous solutions has been investigated by means of total reflection X-ray fluorescence spectroscopy and X-ray photoelectron spectroscopy measurements. Ni contaminants on the Si O2 surface are present in the form of SiO-NiOH. The removal mechanism consists of two steps, i.e., an initial fast process followed by a slow process. The rate-determining steps of both the processes are of the first order with respect to the concentration of cyanide ions (C N-). The fast and slow processes are tentatively attributed to the removal of SiO-NiOH on terraces and in sub-nanometer pores, respectively. The cleaning ability of the HCN aqueous solutions is much better than ammonia aqueous solutions, because of high reactivity to form nickel-cyanide complex ions and avoidance of readsorption of Ni (CN) 4 2- complex ions in the solutions.

The NH3--HCN complex has been observed and characterized in an argon matrix.It is a strongly bonded complex with C3v geometry.New absorptions attributable to perturbed vibrations in each submolecule have been observed, especially a new red-shifted absorption νc3(CH) for the perturbed C-H stretching fundamental with blue-shifted absorptions assigned to νc1(CN), νc2(HCN), and νc2(NH3).A low-frequency absorption assigned to the librational motion of HCN in the complex was also observed and agrees well with calculated results.Comparison with the gas-phase spectrum shows that the matrix interaction stabilizes the complex.Spectra for the higher order 1:2 NH3--(HCN)2 complexes are presented, assigned, and compared to NH3--HCN and (HCN)2.

Reaction of conjugated enynones,1,5-diarylpent-2-en-4-yn-1-ones, with malononitrile and sodium alkoxides in the corresponding alcohols at room temperature for 3–23 h results in the formation of two types of compounds (E)-/(Z)-6-aryl-4-(2-arylethenyl)-2-alkoxypyridine-3-carbonitriles (substituted nicotinonitriles), as the major reaction products in yields up to ca. 40–80%, and 6-aryl-4-arylethynyl-2-alkoxypyridines, as the minor reaction products in yields of 5–17%. Plausible mechanism of this complex and multistep reaction is discussed. The obtained pyridines possess fluorescent properties.

The infrared spectra of the HCN monomer, linear (HCN)2 and cyclic (HCN)3 were measured using a low-temperature matrix isolation technique. Linear (HCN)2 and cyclic (HCN)3 were produced by the photolysis of s-tetrazine and s-triazine respectively. Vibrational analyses of the infrared bands for the C-H stretching, the C-N stretching and H-C-N bending modes were performed with the aid of ab initio calculations; geometrical optimization was carried out using the density functional theory (DFT) method with a 6-31++G** basis set.

The results of a detailed study of the primary and secondary reactions of carbon cluster ions, Cn(1+) (3=20), with HCN are used as a probe of the structures of small carbon cluster ions.The experiments were performed in a Fourier transform ICR mass spectrometer (FTMS), using direct laser vaporization of graphite to form the carbon cluster ions.The only ionic products observed for the HCN reactions were CnX(1+) (primary reaction product) and CnXY(1+) (secondary reaction product) where X and Y = H, CN, or HCN.Radiative association is an important reaction channel.Products resulting from fragmentation of the reactant carbon cluster ion were not observed.Evidence for two structural forms of the n = 7-9 cluster ions is presented.The anomalous behavior of C7(1+) is interpreted by an isomerization mechanism.Low-energy collision-induced dissociation studies of the primary product ions support a mechanism of carbene insertion into the H-CN bond and formation of covalently bonded products.In contrast, the HCN associates weakly with most primary product ions.

The C-N stretch mode of several small nitriles was analyzed by measuring vibrational Stark effects. Conjugated and unconjugated nitriles as well as mono- and dinitriles were immobilized in frozen 2-methyl-tetrahydrofuran glass and examined in externally applied electric fields using FTIR. Room temperature absorption spectra of several nitriles (butyronitrile, hydrogen cyanide, valeronitrile, and deuterated aceonitrile) showed no concentration dependent effects between 2.4 mM and 0.8 M. Difference dipole moments, Δμ, equivalent to the linear Stark tuning rate, were 0.01/f-0.04/f Debye (0.2/f-0.7/f/cm(/MV/cm)) for most samples, with aromatic compounds toward the high end and symmetric dinitriles toward the low end. Most quadratic Stark effects were small and negative, while transition polarizabilities were positive and had a significant effect on Stark line shapes. For aromatic nitriles, transition dipoles and Δμ values agreed with Hammett numbers. Symmetric dinitrile Δμ values decreased monotonically with increasing conjugation of the connecting bridge, likely due to improved mechanical coupling and, to a lesser extent, an increased population of inversion symmetric conformations. Δμ values were close to those expected from bond anharmonicity and ab initio predictions.

The production of gaseous hydrocarbons, nitriles, amines, and hydrazines in a continuous-flow microwave plasma discharge excited in a 20% C2H2+80% N2 mixture at a pressure of 20 Torr is reported. The product analysis was made by Li+ ion attachment mass spectrometry. A variety of N-containing organics (identified as HCnN (n=1-7), NC(CC)nCN (n=0-2), NC(CH2)nCN (n=0-6), CnH2n-1NH2 (n=0-6), CnH2n+1N(H)NH2 (n=0-5), etc.) were formed and these were tentatively assigned to nitriles, amines, and hydrazines. The mass-spectral analysis exhibited progressions differing by 14 mass units. Reaction schemes were proposed to explain the formation of some molecules.

The kinetics of the CN + CH3Br reaction were studied using transient infrared laser absorption spectroscopy to detect CN reactants and HCN products. This reaction has a rate constant of k = (2.20 ± 0.6) × 10-12 exp (453 ± 98/T) cm3 molecule-1 s-1 over the range 298-523 K. Hydrogen abstraction to produce HCN + CH2Br is only a minor reaction product, with a branching fraction of 0.12 ± 0.02. Other product channels, including BrCN + CH3, CH2CN + HBr, CH3CN + Br are likely. An upper limit of 0.01 was established for the HBr yield. These results are in qualitative agreement with recent ab initio calculations.

Charge-transfer interactions (CT) between the electron donor gliclazide (GLC) and the π-acceptors 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and tetracyanoethylene (TCNE) were studied in a chloroform solution and in the solid state. The CT complexes were discussed in terms of formation constants (KCT), molar extinction coefficients (εCT), standard reaction quantities (ΔG° ΔH° and ΔS°), oscillator strength (f), transition dipole moment (μEN), and ionization potential (Ip). The limits of detection (LOD) and limits of quantification (LOQ) have also been reported. The stoichiometry of these complexes was found to be in a 1:1 M ratio. The formed solid CT complexes were also synthesized and characterized using electronic methods, FT-IR, 1H and 13C NMR spectroscopy. Thermogravimetric analysis techniques (TGA/DTA) and differential scanning calorimetry (DSC) were used to determine the thermal stability of the synthesized CT complex. The kinetic parameters (ΔG* ΔH* and ΔS*) were calculated from thermal decomposition data using the Coats-Redfern method. Moreover, density functional theory (DFT) studies are discussed for the charge transfer complex GLC-TCNE, using the B3LYP with 6–311++G (d, p) basis set. The harmonic vibrational frequencies were calculated, and the scaled values have been compared with experimental FT-IR spectra. The calculated 1H and 13C NMR chemical shifts using the GIAO method showed good correlations with the experimental data. The theoretical UV–visible spectrum of the compound and the electronic properties, such as HOMO and LUMO energies, were performed using the time-dependent (TD-DFT) approach with CAM-B3LYP, employing the 6–311++G (d, p) basis set, and good agreement with the theoretical and experimental UV–visible data was found.

We have investigated the spectroscopy and reaction of HCN (DCN) adsorbed on Si(100)-2X1 at TS >= 100 K using HREELS, XPS, and UPS.HCN (DCN) formed dimers and/or polymers on the surface at 100 K and higher dosages ( D > 4 langmuirs).The HREEL spectrum obtained after warming 4.5-langmuir HCN dosed surface to 220 K resembles that obtained with a lower HCN dosage (D a peak at 263 meV due to the CN stretching vibration.In the corresponding DCN experiment, the DC=ND stretching mode was observed at 124 meV.Annealing the sample at 560 K appeared to cause the reorientation of the CN radical from an end-on to a side-on adsorption geometry as evidenced by HREELS, UPS, and XPS analyses.At 600-800 K, the breaking of NH and CN bonds occurred on the surface.Above 1000 K, a mixture of silicon carbide and silicon nitride was formed after the complete dissociation of CH, NH, and CN bonds and the desorption of H species.

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The discharge-flow mass spectrometry technique has been used to measure the kinetics of the reaction N + CH3 -> products over the temperature range 200-423 K.The results are as follows (10-11 cm3 s-1): k1(200 K)

Equilibrium thermochemical measurements using the mass-selected ion mobility (MSIM) technique have been utilized to investigate the binding energies and entropy changes of the stepwise association of hydrogen cyanide (HCN) and acetonitrile (CH3CN) molecules with the naphthalene radical cation (C10H8?+) in the gas phase forming the C10H8?+(HCN)n and C10H8?+(CH3CN)n clusters with n = 1-3 and 1-5, respectively. The lowest energy structures of the C10H8?+(HCN)n and C10H8?+(CH3CN)n clusters for n = 1-2 have been calculated using the M062X and ω97XD methods within the 6-311+G?? basis set, and for n = 1-6 using the B3LYP method within the 6-311++G?? basis set. In both systems, the initial interaction occurs through unconventional CHδ+?N ionic hydrogen bonds between the hydrogen atoms of the naphthalene cation and the lone pair of electrons on the N atom of the HCN or the CH3CN molecule. The binding energy of CH3CN to the naphthalene cation (11 kcal mol-1) is larger than that of HCN (7 kcal mol-1) due to a stronger ion-dipole interaction resulting from the large dipole moment of CH3CN (3.9 D). On the other hand, HCN can form both unconventional hydrogen bonds with the hydrogen atoms of the naphthalene cation (CHδ+?NCH), and conventional linear hydrogen bonding chains involving HCN?HCN interactions among the associated HCN molecules. HCN molecules tend to form externally solvated structures with the naphthalene cation where the naphthalene ion is hydrogen bonded to the exterior of an HCN?HCN chain. For the C10H8?+(CH3CN)n clusters, internally solvated structures are favored where the acetonitrile molecules are directly interacting with the naphthalene cation through CHδ+?N unconventional ionic hydrogen bonds. In both the C10H8?+(HCN)n and C10H8?+(CH3CN)n clusters, the sequential binding energy decreases stepwise to about 6-7 kcal mol-1 by three HCN or CH3CN molecules, approaching the macroscopic enthalpy of vaporization of liquid HCN (6.0 kcal mol-1).

The mechanism of CN bond formation from CH3 and NH3 fragments adsorbed on Pt(111) was investigated with reflection absorption infrared spectroscopy (RAIRS), temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). The surface chemistry of carbon-nitrogen coupling is of fundamental importance to catalytic processes such as the industrial-scale synthesis of HCN from CH4 and NH3 over Pt. Since neither CH4 nor NH3 thermally dissociate on Pt(111) under ultrahigh vacuum (UHV) conditions, the relevant surface intermediates were generated through the thermal decomposition of CH 3I and the electron-induced dissociation of NH3. The presence of surface CN is detected with TPD through HCN desorption as well as with RAIRS through the appearance of the vibrational features characteristic of the aminocarbyne (CNH2) species, which is formed upon hydrogenation of surface CN at 300 K. The RAIRS results show that HCN desorption at a??500 K is kinetically limited by the formation of the CN bond at this temperature. High coverages of Cads suppress CN formation, but the results are not influenced by the coadsorbed I atoms. Cyanide formation is also observed from the reaction of adsorbed N atoms and carbon produced from the dissociation of ethylene. ? 2005 American Chemical Society.

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The hexacyanotitanate salt, [Et4N]3[Ti(CN)6]·4MeCN, has been prepared by addition of tetraethylammonium cyanide to the titanium(III) triflate salt Ti(O3SCF3)3(MeCN)3. The orange crystalline product has been characterized by X-ray diffraction, and the d1 anion is only slightly distorted from ideal O(h) symmetry. The anion resides on a center of symmetry and is characterized by the following parameters: Ti-C = 2.195(2), 2.197(3), and 2.213(3) A?; C-N (av) = 1.141(4) A?; C-Ti-C (cis) = 88.01(9), 88.02(9), 89.02(9), and 89.78(9)°; C-Ti-C (trans) = 180°. In addition to the crystallographic study, details of the IR (ν(CN) = 2071 cm-1), EPR, and UV-vis spectra (Δ(o) = 22800 cm-1) are given. Crystal data for [Et4N]3[Ti(CN)6]·4MeCN are as follows: monoclinic, space group I2/a, a = 18.171(6) A?, b = 12.200(4) A?, c = 20.989(5) A?, β = 91.17(2)°, V = 4652(2) A?3, Z = 4, wR2 = 0.2054 for 3831 data, 27 restraints, and 318 parameters.

Treatment of an aqueous solution of Na[B(CN)4] with an acidic cation exchange resin leads to a solution of the strong tetracyanoboronic acid. Evaporation of the solution at room temperature yields colourless single crystals of [H5O2][B(CN)4] (P4n2, a = 9.5830(2) A, c = 14.25440(3) A, Z = 1). Further drying of [H 5O2][B(CN)4] (mp. 115 °C) in vacuum at 50 °C gives polycrystalline [H3O][B(CN)4] (P6 3mc, a = 8.704(1) A, c = 6.152(1) A, Z = 2), which is thermally stable up to 145 °C The anhydrous polycrystalline acid H[B(CN)4] is formed quantitatively by reacting Me 3SiNCB(CN)3 with gaseous HCl. This acid starts to decompose at 190 °C with loss of HCN. All three acids were further characterized by vibrational spectroscopy, and elemental analysis.

Considerable attention has been focused on developing a synthetic route to a carbon-nitrogen material with mechanical and thermal properties comparable or superior to those of diamond. To date, no substance with the desired C3N4 stoichiometry in a silicon-nitride crystal lattice has been reported. One of the principal difficulties in the pursuit of ultrahard carbon-nitrogen (CN) solids is the characterization of amorphous CN samples. We describe a solid-state NMR study of a paracyanogen-like solid utilizing 13C-15N adiabatic-passage Hartmann-Hahn cross-polarization (APHH-CP) to perform dipolar filtering and show that this method is well-suited for recoupling 13C-15N in network solids. In addition, high-frequency electron paramagnetic resonance (EPR) indicates a density of electron spins of approximately 1 × 1017 e-/cm3. We conclude by discussing how NMR and EPR data may be useful for optimizing CN-polymer samples as potential precursors for ultrahard carbon nitrogen solids.

We measured the mobility of excess electrons in the polar hydrogen cyanide gas (D=2.985 D) at low densities as a function of density and temperature by the so-called pulsed Townsend method. Experiments were performed at 294 and 333 K in the gas number density range 1.23×1017≤n≤3.61×1018 cm-3. We found a strong density dependence of the zero-field density-normalized mobility (μn). Only about 10% of the observed density variation can be qualitatively explained by coherent and incoherent multiple scattering effects. With increasing gas density an increasing number of linear HCN dimers is formed which due to the high dipole moment (D=6.552 D) represent much stronger electron scatterers than the HCN monomers. It was found that the dimers may be only in part responsible for the observed density effect. Therefore, we consider a transport process where short-lived dipole-bound electron ground states (lifetime ≥12 ps) as quasilocalized states are involved. For comparison the electron mobility in saturated 2-aminoethanol vapor with a dipole moment of similar size (D=3.05 D) does not show any anomalous density behavior in the temperature range 298≤T≤435 K. In contrast to this the electron mobility in saturated but also in nonsaturated CH3CN gas (D=3.925 D) shows a density behavior similar to that in HCN.

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The rate constants for the reactions of CN radicals with methane, ethane, propane, cyclopropane, isobutane, and neopentane have been measured over a temperature range from 275 to 455 K.Laser photolysis was used to produce the radicals and time delayed laser induced fluorescence was used to follow the radical concentration as a function of time.The temperature dependence of the observed rate constant could be fitted with a three-parameter Arrhenius plot.The activation energies that were observed were all small and in some cases they were negative.Time resolved ir emission was used to follow the formation of the HCN(0n2) and HCN (0n'1) product emission.The time dependence of the relative emission intensities, as well as computer modeling of the decay curves, suggest that vibrational population inversion occurs for all of the hydrocarbons studied except methane and cyclopropane.These observations are discussed in terms of the current theories for these type of reactions.

The kinetics of the reaction of isobutane with N(4S) have been studied as a function of reactant concentration and temperature from 300 to 550 K.The initial rate of consumption of N(4S) was second order in N(4S) and first order in isobutane.The initiation step which best describes the results is N + N + i-C4H10 -> N2 + CH3 + 2-C2H7 and its rate constant fits the expression k = 2.26 * 1017 exp(-3890/T) dm6 mol-2 s-1 A mechanism is proposed for the reaction which quantitatively accounts for the consumption of N(4S) and the production of HCN as a function of both temperature and time.HCN arises in this mechanism from reactions of N(4S) with CH3, 2-C3H7 and other alkyl radicals formed in subsequent reactions.

Tetramethylammonium cyanosulfite decomposes in SO2 at -70°C to give HCN, [(CH3)4N]+HSO4- ·SO2 and [(CH3)4N+]2S2O 72-·2 SO2. A reaction sequence for the decomposition is discussed. The formed salts are characterized by infrared, Raman spectroscopy, and single crystal X-ray diffraction. [(CH3)4N]+HSO4- ·SO2 crystallizes in the monoclinic space group P21/n with a = 709.2(1) pm, b = 1479.7(1) pm, c = 989.6(1) pm, β = 90.86(1)° and four formula units per unit cell. [(CH3)4N+]2S2O 72-·2 SO2 crystallizes in the monoclinic space group P21/n with a = 1212.9(1) pm, b = 1970.1(1) pm, c = 1773.8(1) pm, β = 109.42(1)° and eight formula units per unit cell.

Organophosphorus compounds (OPCs) have gained tremendous interest in the past decades due to their wide applications ranging from synthetic chemistry to materials and biological sciences. We describe herein a practical and versatile approach for the trans

Despite the significant achievements related to the C3 functionalization of indoles, cyanoalkylation reactions continue to remain rather limited. We herein report on the formal C3 cyanoalkylation of indoles with cyanohydrins in the presence of a tris(pentafluorophenyl)borane (B(C6F5)3) catalyst. It is noteworthy that cyanohydrins are used as a cyanoalkylating reagent in the present reaction, even though they are usually used as only a HCN source. Mechanistic investigations revealed the unique reactivity of the B(C6F5)3 catalyst in promoting the decomposition of a cyanohydrin by a Lewis acidic activation through the coordination of the cyano group to the boron center. In addition, a catalytic three-component reaction using indoles, aldehydes as a carbon unit, and acetone cyanohydrin that avoids the discrete preparation of each aldehyde-derived cyanohydrin is also reported. The developed methods provide straightforward, highly efficient, and atom-economic access to various types of synthetically useful indole-3-acetonitrile derivatives containing α-tertiary or quaternary carbon centers.

The magneto-optical phenomenon known as Faraday rotation involves the rotation of plane-polarized light as it passes through an optical medium in the presence of an external magnetic field oriented parallel to the direction of light propagation. Faraday rotators find applications in optical isolators and magnetic-field imaging technologies. In recent years, organic thin films comprised of polymeric and small-molecule chromophores have demonstrated Verdet constants, which measure the magnitude of rotation at a given magnetic field strength and material thickness, that exceed those found in conventional inorganic crystals. We report herein the thin-film magnetic circular birefringence (MCB) spectra and maximum Verdet constants of several commercially available and newly synthesized phthalocyanine and porphyrin derivatives. Five of these species achieved maximum Verdet constant magnitudes greater than 105 deg T-1 m-1 at wavelengths between 530 and 800 nm. Notably, a newly reported zinc(II) phthalocyanine derivative (ZnPc-OT) reached a Verdet constant of -33 × 104 deg T-1 m-1 at 800 nm, which is among the largest reported for an organic material, especially for an optical-quality thin film. The MCB spectra are consistent with resonance-enhanced Faraday rotation in the region of the Q-band electronic transition common to porphyrin and phthalocyanine derivatives, and the Faraday A-term describes the electronic origin of the magneto-optical activity. Overall, we demonstrate that phthalocyanines and porphyrins are a class of rationally designed magneto-optical materials suitable for applications demanding large Verdet constants and high optical quality.

A catalytic enantioselective Strecker reaction of isatin-derived N-unsubstituted ketimines directly afforded the N-unprotected α-aminonitriles with a tetrasubstituted carbon stereocenter in up to 99% ee without requiring protection/deprotection steps. One-pot Strecker reactions from the parent carbonyl compounds were also realized with comparable yields and enantioselectivities. Direct transformations of the N-unprotected α-aminonitrile products streamlined the synthesis of unnatural amino acid derivatives and achieved the shortest one-pot stereoselective routes to a biologically active compound reported to date.

The trapping of classical hydrogen pseudohalides (HX, X = pseudohalogen = CN, N3, NCO, NCS, and PCO) utilizing a phosphorus-centered cyclic biradicaloid, [P(μ-NTer)]2, is reported. These formal Br?nsted acids were generatedin situas gases and passed over the trapping reagent, the biradicaloid [P(μ-NTer)]2, leading to the formation of the addition product [HP(μ-NTer)2PX] (successful for X = CN, N3, and NCO). In addition to this direct addition reaction, a two-step procedure was also applied because we failed in isolating HPCO and HNCS addition products. This two-step process comprises the generation and isolation of the highly reactive [HP(μ-NTer)2PX]+cation as a [B(C6F5)4]?salt, followed by salt metathesis with salts such as [cat]X (cat = PPh4,n-Bu3NMe), which also gives the desired [HP(μ-NTer)2PX] product, with the exception of the reaction with the PCO?salt. In this case, proton migration was observed, finally affording the formation of a [3.1.1]-hetero-propellane-type cage compound, an OC(H)P isomer of a HPCO adduct. All discussed species were fully characterized.

Nitrosation of cyanamide leads to unstable E/Z-cyanodiazohydroxides that easily deprotonate to E/Z-cyanodiazotates. Pursuing observations of E. Drechsel 145 years ago, the structure and reactivity of those products was determined, mainly in aqueous solution. Depending on the pH, three different thermal decomposition pathways give either N2O + HCN or N2 + HNCO. They were evaluated experimentally and by quantum mechanical calculations.

The invention relates to a process for producing a product gas comprising acetonitrile and/or hydrogen cyanide from a feed stream comprising ammonia and methanol over a solid catalyst comprising a support, a first metal and a second metal on the support, wherein the first metal and the second metal are in the form of a chemical compound, wherein the first metal is Fe, Ru or Co and the second metal is Sn, Zn, or Ge. The pressure is ambient pressure or higher and the temperature lies in a range from about 400° C. to about 700° C. Thus, the process for producing acetonitrile and/or hydrogen cyanide from ammonia and methanol may be catalyzed by a single catalyst and may be carried out in a single reactor. The invention also relates to a catalyst, a method for activating a catalyst and use of a catalyst for catalysing production of acetonitrile and/or hydrogen cyanide from ammonia and methanol.

Complexes formed by interaction of E(C6F5)3 (E = B, Al, Ga, In) with excess of acetonitrile (AN) were structurally characterized. Quantum chemical computations indicate that for Al(C6F5)3 and In(C6F5)3 the formation of a complex of 1:2 composition is more advantageous than for B(C6F5)3 and Ga(C6F5)3, in line with experimental observations. Formation of the solvate [Al(C6F5)3·2AN]·AN is in agreement with predicted thermodynamic instability of [Al(C6F5)3·3AN]. Tensimetry study of B(C6F5)3·CH3CN reveals its stability in the solid state up to 197 °C. With the temperature increase, the complex undergoes irreversible thermal decomposition with pentafluorobenzene formation.

The present invention relates to a process for producing a compound of the formula (I) comprising at least the process step: a) reacting a compound of the formula (II) with hydrogen and water in the presence of at least one homogeneous transition metal catalyst TMC 1.

Reducing greenhouse gas and pollutant emissions is one of the most stringent priorities of our society to minimize their dramatic effects on health and environment. Natural gas (NG) engines, in particular at lean conditions, emit less CO2 in comparison to combustion engines operated with liquid fuels but NG engines still require emission control devices for NOx removal. Using state-of-the-art technologies for selective catalytic reduction (SCR) of NOx with NH3, we evaluated the interplay of the reducing agent NH3 and formaldehyde, which is always present in the exhaust of NG engines. Our results show that a significant amount of highly toxic hydrogen cyanide (HCN) is formed. All catalysts tested partially convert formaldehyde to HCOOH and CO. Additionally, they form secondary emissions of HCN due to catalytic reactions of formaldehyde and its oxidation intermediates with NH3. With the present components of the exhaust gas aftertreatment system the HCN emissions are not efficiently converted to non-polluting gases. The development of more advanced catalyst formulations with improved oxidation activity is mandatory to solve this novel critical issue.

The present invention relates to catalyst compositions containing a mixed oxide catalyst of formula (I) or formula (II) as described herein, their preparation, and their use in a process for ammoxidation of various organic compounds to their corresponding nitriles and to the selective catalytic oxidation of excess NH3 present in effluent gas streams to N2 and/or NOx.

A continuous process for the on-demand generation, separation, and reaction of hydrogen cyanide (HCN) using membrane separation technology was developed. The inner tube of the reactor is manufactured from a gas-permeable, hydrophobic fluoropolymer (Teflon AF-2400) membrane. HCN is formed from aqueous reagents within the inner tube and then diffuses through the membrane into an outer tubing containing organic solvent. This technique enabled the safe handling of HCN for three different organic transformations without the need for distillation.

Evolution of hydrogen cyanide (HCN) during amino acid activation using the reagent combination ethyl cyano(hydroxyimino)acetate (Oxyma)/diisopropylcarbodiimide (DIC) is observed under ambient conditions (20 °C) in N,N-dimethylformamide (DMF). Concentration versus time profiles obtained by 1H NMR spectroscopy in the presence and absence of amino acids indicate that HCN is formed upon addition of DIC to the reaction mixture and that HCN evolution continues to occur even after amino acid activation is complete when Oxyma and DIC are used in excess amounts relative to the amino acid. A mechanism for the reaction between Oxyma and DIC is proposed, and evidence for its validity was gathered by NMR spectroscopy.

This paper focuses on the thermal behavior of mixtures of ammonium dinitramide (ADN) and amine nitrates. Because some mixtures of ADN and amine nitrate exhibit low melting points and high-energy content, they represent potential liquid propellants for spacecraft. This study focused on the melting behavior and thermal-decomposition mechanisms in the condensed phase of ADN/amine nitrate mixtures during heating. We measured the melting point and exothermal behavior during constant-rate heating using differential scanning calorimetry and performed thermogravimetry–differential thermal analysis–mass spectrometry (TG–DTA–MS) to analyze the thermal behavior and evolved gases of ADN/amine nitrate mixtures during simultaneous heating to investigate their reaction mechanisms. Results showed that the melting point of ADN was significantly lowered upon the addition of amine nitrate with relatively low molecular volume and low melting point. TG–DTA–MS results showed that the onset temperature of the thermal decomposition of ADN/amine nitrates was similar to that of pure ADN. Furthermore, during thermal decomposition in the condensed phase, ADN produced highly acidic products that promoted exothermic reactions, and we observed the nitration and nitrosation of amines from the dissociation of amine nitrates.

Starting from fluoridosilicate precursors in neat cyanotrimethylsilane, Me3Si?CN, a series of different ammonium salts [R3NMe]+ (R=Et, nPr, nBu) with the novel [SiF(CN)5]2? and [Si(CN)6]2? dianions was synthesized in facile, temperature controlled F?/CN? exchange reactions. Utilizing decomposable, non-innocent cations, such as [R3NH]+, it was possible to generate metal salts of the type M2[Si(CN)6] (M+=Li+, K+) via neutralization reactions with the corresponding metal hydroxides. The ionic liquid [BMIm]2[Si(CN)6] (m.p.=72 °C, BMIm=1-butyl-3-methylimidazolium) was obtained by a salt metathesis reaction. All the synthesized salts could be isolated in good yields and were fully characterized.

A tandem radical relay strategy was realized for the first Cu(I)-catalyzed enantioselective phosphinocyanation of styrenes. In this reaction, tBuOOSiMe3 generated in situ from tBuOOH serves as a radical initiator to trigger t-butoxy radical production upon oxidization of L?Cu(I) species via proton-coupled-electron transfer (PCET) pathway, which leads to sequential phosphinoyl radical and benzyl radical formations. The resultant β-cyanodiarylphosphine oxides could be easily converted to a series of chiral ?-amino phosphine ligands.

Alkynyl isocyanates have been postulated as highly reactive intermediates in synthetic chemistry. Herein, the parent molecule HC≡CNCO is isolated for the first time. In sharp contrast to the previously reported short lifetime (ca. 15 s) at room temperature, we found that HC≡CNCO has a lifetime of 55 h in the gas phase (2 mbar, 300 K) with a melting point of ?79.5 °C and vaporization enthalpy (ΔHvap) of 23.1(1) kJ mol?1. Apart from the IR (gas, solid, and matrix), 1H and 13C NMR, and UV/Vis spectroscopic characterization, its photoisomerization with a acylnitrene HC≡CC(O)N and cyanoketene NCC(H)CO has been observed.

In cyanation reactions, the cyanide source is often directly added to the reaction mixture, which restricts the choice of conditions. The spatial separation of cyanide release and consumption offers higher flexibility instead. Such a setting was used for the cyanation of iminium ions with a variety of different easy-to-handle HCN sources such as hexacyanoferrate, acetonitrile or α-amino acids. The latter substrates were first converted to their corresponding nitriles through oxidative decarboxylation. While glycine directly furnishes HCN in the oxidation step, the aliphatic nitriles derived from α-substituted amino acids can be further converted into the corresponding cyanohydrins in an oxidative C-H functionalization. Mn(OAc)2 was found to catalyze the efficient release of HCN from these cyanohydrins or from acetone cyanohydrin under acidic conditions and, in combination with the two previous transformations, permits the use of protein biomass as a non-toxic source of HCN.

A highly labile dimer of hydrogen cyanide, HCN???HCN, was extracted from liquid HCN by adduct formation with the bulky Lewis acid B(C6F5)3, affording HCN???HCN?B(C6F5)3, which was fully characterized. The influence of the solvent (HCN, CH2Cl2, and aromatic hydrocarbons) on the crystallization process was studied, revealing dimer formation when using HCN or CH2Cl2 as solvent, whereas aromatic hydrocarbons led to the formation of monomeric arene??HCN?B(C6F5)3 adducts, additionally stabilized by η6-coordination of the aromatic ring system similar to well-known half-sandwich complexes.

A novel synthetic method for the preparation of perfluoroallyl cyanide CF2[dbnd]CFCF2CN (PFACN) is presented. This includes the addition – elimination reaction of cyanide anion with perfluoroallyl fluorosulfate CF2[dbnd]CF

By milling 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) together, a nano CL-20/RDX co/mixed crystal explosive with a mean particle size of 141.6?nm is prepared from the raw materials, and the co/mixed crystals are characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC) and thermal-infrared spectrometry online (DSC-IR) technology; furthermore, the impact, friction and thermal sensitivity of the samples are tested. The results show that after milling, the morphology of the co/mixed crystal explosive is near-spherical, and the particle size reveals a normal distribution. The milled sample showed the same molecular structure and surface elements as the raw materials, but the XRD test shows that CL-20/RDX has a new crystal phase and the Raman and IR spectra gave a supplementary confirmation for the existence of a cocrystal phase in the milled sample. The activation energy of the thermal decomposition of CL-20/RDX is 206.49 kJ mol?1 higher than that of raw RDX. DSC-IR analysis showed that the thermolysis of CL-20/RDX produces a large amount of CO2 and N2O and a small amount of H2O, NO2 and NO. The mechanical sensitivity of CL-20/RDX is very low. In impact sensitivity tests with a 5 kg hammer, the special height (H50) is 51.43 cm, which is higher than the values of 36.43 cm for raw CL-20 and 9.78 cm for raw RDX. In the friction sensitivity tests, the explosion probability (P) is 56%; however, the thermal sensitivity of CL-20/RDX is higher than that of the raw materials, with its 5 s burst point being only 243.51 °C.

Biocatalysts originating from Badamu (Prunus communis) have been applied to catalyze the asymmetric synthesis of (R)-4-methylsulfanylmandelonitrile, a key building block of thiamphenicol and florfenicol. Here, four hydroxynitrile lyase (HNL) isozymes from Badamu were cloned and heterologously expressed in Pichia pastoris. The biochemical properties and catalytic performances of these isozymes were comprehensively explored to evaluate their efficiency and selectivity in asymmetric synthesis. Among then, PcHNL5 was identified with outstanding activity and enantioselectivity in asymmetric hydrocyanation. Under the optimized mild biphasic reaction conditions, seventeen prochiral aromatic aldehydes were converted to valuable chiral cyanohydrins with good yields (up to 94%) and excellent optical purities (up to >99.9% ee), which provide a facile access to numerous chiral amino alcohols, hypoglycemic agents, angiotension converting enzyme (ACE) inhibitors and β-blockers. This work therefore underlines the importance of discovering the most potent biocatalyst among a group of isozymes for converting unnatural substrates into value-added products. (Figure presented.).

Abstract: Hydroxynitrile lyases (HNLs) are increasingly finding application in the synthesis of enantiomerically pure cyanohydrins which are important intermediates in the production of pharmaceuticals and agrochemicals. Synthesis of enantiopure mandelonitrile was carried out using HNL of wild apricot (Prunus armeniaca L.) [ParsHNL] in aqueous/organic biphasic system. The optimum pH and temperature of the reaction were 4.0 and 15 °C respectively, which are important parameters to suppress the non-enzymatic catalysis. ParsHNL catalyses synthesis of (R)-mandelonitrile in methyl-tbutyl ether (MTBE)/citrate buffer biphasic system with >99% ee. Synthesis of mandelonitrile was carried out in batch reaction at 40?ml scale and finally 2.7 mmoles of (R)-mandelonitrile was recovered which corresponded to 90% molar conversion in 46?h reaction. In fed batch reaction 6.37 mmoles of (R)-mandelonitrile could be produced which corresponds to 91% molar conversion in 46?h. In both reactions, enzyme produces (R)-mandelonitrile with > 99% ee which showed enhanced selectivity as compared to aqueous reaction (96% ee) by ParsHNL. The results showed potential of ParsHNL to synthesize (R)-mandelonitrile in both, batch reaction and fed-batch reaction and can be effectively used in the synthesis of (R)-mandelonitrile. Graphical Abstract: [Figure not available: see fulltext.].

THE CHEMOENZYMATIC reaction of selected aldehydes, namely 2-chlorobenzaldehyde (1a), 4-fluorobenzaldehyde (1b), benzo[d][1,3]dioxole-5-carbaldehyde (1c) and/or 2,3-dihydrobenzo [b] [1,4] dioxine-6-carbaldehyde (1d) with hydrogen cyanide in presence of (R)-oxynitrilase (R)-Pa HNL [EC 4.1.2.10] from almonds, as a chiral catalyst, gave the optically active cyanohydrin enantiomers ( R)-2a-c, respectively. Acetone cyanohydrin (3), was also used, as a transcyanating agent, to give the same products. The racemic cyanohydrins (R,S)-2a-d have been synthesized, as well, by treating compounds 1a-d with aqueous potassium cyanide solution in presence of a saturated solution of sodium metabisulphite (Na2S2O5). The optical purity of cyanohydrins (R)-2a-c was determined through their derivatization with (S)-naproxen chloride (S)-5 to the respective diastereomers (R,2S)-6a-c which were obtained in diastereomeric excess (de) values up to 93 % (1H NMR). Heating compounds (R)-2a,b and / or their racemic analogues (R,S)-2a-c with concentrated hydrochloric acid gave the respective α-hydroxycarboxylic acids 7a-c. Moreover, reduction of cyanohydrins (R,S)-2b,c under different conditions resulted in a hydrodecyanation giving the respective primary alcohols 8a,b. Structures and configurations of the new compounds were confirmed with compatible elementary microanalyses and spectroscopic (IR, 1H NMR, 13C NMR, MS and single crystal X-ray crystallography) measurements. The antimicrobial activity of derivatives 6a-d against four bacterial species (Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa) and two fungi (Aspergillus flavus and Candida albicans) were undertaken. Moreover, compounds (R,2S)-6b, (R,2S)(S,2S)-6b and (R,2S)-6c were screened for their in virto antitumor activity against three human solid cancer cell lines (HCT 116, HepG2 and MCF-7). In general, the tested compounds were found inactive or showed weak activities in comparison with the standard drugs.

New insights on the gas-phase ammoxidation of ethanol to acetonitrile over supported vanadia catalysts were obtained by means of reactivity experiments (in ethanol ammoxidation and oxidation) as well as in situ Raman and DRIFT spectroscopy. It was found that the rate-determining step during the redox process depends on the support type. In the case of V2O5/ZrO2, the V oxidation state under reaction conditions is closer to V5+, whereas with V2O5/TiO2, the reduction of V5+ is faster than the re-oxidation of the corresponding reduced V species by O2; thus, the V oxidation state under steady state conditions is lower than for V2O5/ZrO2. In the latter catalyst, the more oxidized V species is responsible for ammonia activation and reaction with the intermediate acetaldehyde, leading in the end to a better acetonitrile yield than with V2O5/TiO2. It was also found that V2O5/ZrO2 is more selective to acetaldehyde than V2O5/TiO2. With the former catalyst, ethanol is able to reduce V2O5 only to a limited extent. Conversely, V2O5/TiO2 is readily reduced by ethanol but this reduced V species is responsible for an unselective oxidation of the alcohol, giving more CO and CO2.

The use of ionic liquids (ILs) as advanced electrolyte components in electrochemical energy-storage devices is one of the most appealing and emerging options. However, although ILs are hailed as safer and eco-friendly electrolytes, to overcome the limitations imposed by the highly volatile/combustible carbonate-based electrolytes, full-scale and precise appraisal of their overall safety levels under abuse conditions still needs to be fully addressed. With the aim of providing this level of information on the thermal and chemical stabilities, as well as actual fire hazards, herein, a detailed investigation of the short- and long-term thermal stabilities, biodegradability, and combustion behavior of various pyrrolidinium-based ILs, with different alkyl chain lengths, counteranions, and cations, as well as the effect of doping with lithium salts, is described.

A thermally induced topotactic transformation of organic polymeric semiconductors is achieved using similarity of the chemical structures of two C,N,H-containing materials. Namely, the oligomer of 3-amino-1,2,4-triazole (OATA) is transformed into an elect

The invention relates to a methanol or formaldehyde ammoxidizing the method of synthesizing amide. Using methanol or formaldehyde, ammonia and air as the raw materials, in 1-3 gas reactor is continuously carried out in a catalytic reaction, synthesis (C-C) is provided with a carbon-carbon single bond or carbon-carbon-carbon single bond amide (C-C-C) organic compound (called C 2 or C 3 amide, mainly hydroxy acetamide, amino acetamide, diglycolamidic amide, malonamide and nitrilo- three b amide).

Reaction of C63NO2(Ph)2(Py) (1) with o-phenylenediamine and pyridine produces a mixture of C63H4NO2(Ph)2(Py)(N2C6H4) (2) and H2O@2. Compound 2 is a new open-cage fullerene containing a 20-membered heterocyclic orifice, which has been fully characterized by NMR spectroscopy, high-resolution mass spectrometry, and X-ray crystallography. The elliptical orifice of 2 spans 7.45 ? along the major axis and 5.62 ? along the minor axis, which is large enough to trap water and small organic molecules. Thus, heating a mixture of 2 and H2O@2 with hydrogen cyanide and formaldehyde in chlorobenzene affords HCN@2 and H2CO@2, respectively. The1H NMR spectroscopy reveals substantial upfield shifts for the endohedral species (δ=?1.30 to ?11.30 ppm), owing to the strong shielding effect of the fullerene cage.

An enantioselective preparation of O-acetylcyanohydrins has been accomplished by a three-step telescoped continuous process. The modular components enabled an accurate control of two sequential biotransformations, safe handling of an in situ generated hazardous gas, and in-line stabilization of products. This method proved to be advantageous over the batch protocols in terms of reaction time (40 min vs 345 min) and ease of operation, opening up access to reactions which have often been neglected due to safety concerns.

IR diode laser spectroscopy was used to detect the products of HCNO (fulminic acid) photolysis at 193 nm. Six product channels are energetically possible at this photolysis wavelength: O + HCN, H + NCO/CNO, CN + OH, CO + NH, NO + CH and HNCO. In some experiments, isotopically labeled 15N18O, C2D6 or C6H12 reagents were included into the photolysis mixture in order to suppress and/or redirect possible secondary reactions. HCN, OC18O, 15N15NO, CO, DCN and HNCO molecules were detected upon laser photolysis of HCNO/reagents/buffer gas mixtures. Analysis of the yields of product molecules leads to the following photolysis quantum yields: φ1a (O + HCN) = 0.38 ± 0.04, φ1b (H + (NCO)) = 0.07 ± 0.02, φ1c (CN + OH) = 0.24 ± 0.03, φ1d (CO + NH(a1Δ)) 1e (HNCO) = 0.02 ± 0.01 and φ1f (CH + NO) = 0.21 ± 0.1, respectively.

This paper is in continuation of our previous report which was based on a 532 nm wavelength pulsed photoacoustic (PA) technique with nitro rich energetic materials named 1-(4-methyl-3,5-dinitrophenyl)-1H-1,2,4-triazole (p-Me-DNPT), 1-(4-methoxy-3,5-dinitrophenyl)-1H-1,2,4-triazole (p-OMe-DNPT), and 2,6-dinitro-4-(1H-1,2,4-triazol-1-yl) aniline (p-NH2-DNPT) in the 30-350 °C temperature range. In the present work, the PA fingerprint spectra, thermal stability and efficiency of these compounds as rocket fuel have been evaluated using the fourth harmonic i.e. 266 nm wavelength of 7 ns pulse duration and 10 Hz repetition rate as an excitation source. The entire study is based on the photodissociation process due to the π? ← n electronic transition in NO2 molecules which is initiated inside the PA cell. The result obtained from the PA technique and thermogravimetric-differential thermal analysis (TG-DTA) data confirm the multistep decomposition mechanism. The study also provides the stable thermal quality factor "Q" which is linked to the stability of the compound.

The influence of the position of the methyl substituent in 1- and 2-methyl-substituted 5-aminotetrazoles on the photochemistry of these molecules is evaluated. The two compounds were isolated in an argon matrix (15 K) and the matrix was subjected to in situ narrowband UV excitation at different wavelengths, which induce selectively photochemical transformations of different species (reactants and initially formed photoproducts). The progress of the reactions was followed by infrared spectroscopy, supported by quantum chemical calculations. It is shown that the photochemistries of the two isomers, 1-methyl-(1H)-tetrazole-5-amine (1a) and 2-methyl-(2H)-tetrazole-5-amine (1b), although resulting in a common intermediate diazirine 3, which undergoes subsequent photoconversion into 1-amino-3-methylcarbodiimide (H2N-N=C=N-CH3), show marked differences: formation of the amino cyanamide 4 (H2N-N(CH3)-C=N) is only observed from the photocleavage of the isomer 1a, whereas formation of the nitrile imine 2 (H2N-C-=N+=N-CH3) is only obtained from photolysis of 1b. The exclusive formation of nitrile imine from the isomer 1b points to the possibility that only the 2H-tetrazoles forms can give a direct access to nitrile imines, while observation of the amino cyanamide 4 represents a novel reaction pathway in the photochemistry of tetrazoles and seems to be characteristic of 1H-tetrazoles. The structural and vibrational characterization of both reactants and photoproducts has been undertaken.

A synthesis of (+)-17-epi-methoxy-kauran-3-one, an O-methylated isomer of the natural diterpene 17-hydroxy-kauran-3-one, has been achieved. The strategy is based on a diastereoselective oxidative polycyclization-pinacol tandem process consisting of transforming a functionalized phenol into a compact and complex tetracycle, which represents the main core of kaurane family members. The synthesis also includes an enantioselective Yamamoto's allylation, a diastereoselective Ru-catalyzed hydrocyanation, a ring-closing metathesis and a reductive isomerization process as key steps. The structure of our synthetic substrate was determined through comparison with an O-methylated derivative of the natural compound.

MoVTeNbO catalysts were characterized with XRD, XPS, and FTIR techniques and tested in the ammoxidation of propane. Bismuth-modified MoVTeNbO catalysts showed a higher acrylonitrile yield than the base four-component system. The effect of the reaction mixture composition (C3H8, NH3 and O2) on selectivity towards different products was studied at propane conversion above 80%. The favorable effect of bismuth promoter on the selectivity towards acrylonitrile was explained by suppression of acrylonitrile transformation connected with decreasing acidity of the catalyst.

The solid phase behavior of a series of monosubstituted F-, Cl-, Br-, I-, and CH3- and two 2,4-halogen-disubstituted 2-hydroxy-2-phenylacetic acid (mandelic acid) derivatives was investigated. The study includes detailed information about melting temperature, melting enthalpy, X-ray diffraction data, as well as selected binary phase diagrams of the respective chiral systems. Aside from the known metastable conglomerate 2-chloromandelic acid, evidence for two more metastable conglomerates was found.

Without the addition of any chiral substances, the spontaneous formation of an enantioenriched α-amino nitrile (up to 96% ee), which is a chiral precursor for Strecker amino acid synthesis, has been achieved in combination with conglomerate formation. The frequency of the formation of enantiomorphs exhibits an approximate stochastic distribution, i.e., l-form occurred 21 times and d-form occurred 22 times, which fulfils the conditions necessary for spontaneous absolute asymmetric synthesis.

The bimolecular reactions that follow 267 nm ultraviolet photolysis of ICN in acetonitrile solution have been studied using transient absorption spectroscopy on the picosecond time scale. Time-resolved electronic absorption spectroscopy (TEAS) in the ultraviolet and visible spectral regions observes rapid production and loss (with a decay time constant of 0.6 ± 0.1 ps) of the photolytically generated free CN radicals. Some of these radicals convert to a solvated form which decays with a lifetime of 8.5 ± 2.1 ps. Time-resolved vibrational absorption spectroscopy (TVAS) reveals that the free and solvated CN-radicals undergo geminate recombination with I atoms to make ICN and INC, H atom abstraction reactions, and addition reactions to solvent molecules to make C3H3N2 radical species. These radical products have a characteristic absorption band at 2036 cm-1 that shifts to 2010 cm-1 when ICN is photolyzed in CD3CN. The HCN yield is low, suggesting the addition pathway competes effectively with H atom abstraction from CH3CN, but the delayed growth of the C3H3N2 radical band is best described by reaction of solvated CN radicals through an unobserved intermediate species. Addition of methanol or tetrahydrofuran as a cosolute promotes H atom abstraction reactions that produce vibrationally hot HCN. The combination of TEAS and TVAS measurements shows that the rate-limiting process for production of ground-state HCN is vibrational cooling, the rate of which is accelerated by the presence of methanol or tetrahydrofuran.

We study the gas-phase pyrolysis of benzyl azide (BA, C6H5CH2N3) using ultraviolet photoelectron spectroscopy (UVPES) and matrix-isolation infrared (IR) spectroscopy, together with electronic structure calculations and Rice-Ramsperger-Kassel-Marcus (RRKM) calculations. It is found that BA decomposes via N2 elimination at ca. 615 K, primarily yielding benzenemethaninime. Other end products include HCN and C6H6. N-Methyleneaniline is not detected, although its formation at higher temperature is foreseen by RRKM calculations.

Azines are important in many extraterrestrial environments, from the atmosphere of Titan to the interstellar medium. They have been implicated as possible carriers of the diffuse interstellar bands in astronomy, indicating their persistence in interstellar space. Most importantly, they constitute the basic building blocks of DNA and RNA, so their chemical reactivity in these environments has significant astrobiological implications. In addition, N and O atoms are widely observed in the ISM and in the ionospheres of planets and moons. However, the chemical reactions of molecular anions with abundant interstellar and atmospheric atomic species are largely unexplored. In this paper, gas-phase reactions of deprotonated anions of benzene, pyridine, pyridazine, pyrimidine, pyrazine, and s-triazine with N and O atoms are studied both experimentally and computationally. In all cases, the major reaction channel is associative electron detachment; these reactions are particularly important since they control the balance between negative ions and free electron densities. The reactions of the azine anions with N atoms exhibit larger rate constants than reactions of corresponding chain anions. The reactions of azine anions with O atoms are even more rapid, with complex product patterns for different reactants. The mechanisms are studied theoretically by employing density functional theory; spin conversion is found to be important in determining some product distributions. The rich gas-phase chemistry observed in this work provides a better understanding of ion-atom reactions and their contributions to ionospheric chemistry as well as the chemical processing that occurs in the boundary layers between diffuse and dense interstellar clouds.

A convenient and efficient procedure has been developed for the synthesis of 1-azidoadamantane, 1-adamantyl isocyanate, and 1-adamantyl isothiocyanate by reaction of 1,3-dehydroadamantane with hydrazoic, isocyanic, and isothiocyanic acids, respectively, under mild conditions. The reaction of 1,3-dehydroadamantane with hydrogen cyanide under analogous conditions gives adamantane-1-carbonitrile in a poor yield which may be improved using hexane as solvent.

Decomposition of the extremely explosive and unstable parent compound of 1-azidoalkynes, HCCN3 (azidoacetylene), was studied in the gas phase, solid argon matrix, and solutions. In the gas phase, this azide decomposes quickly at room temperature with a half-life time (t1/2) of 20 min at an initial pressure (p0) of 0.8 mbar. The decay (p0 = 1.0 mbar) is significantly increased in an atmosphere of O2 with t 1/2 of 3 min, in which HC(O)CN was identified as the trapping product of the cyanocarbene intermediate HCCN. Trapping products of this carbene by solvent molecules (CH2Cl2 and CHCl3) were also found during decomposition of the azide in solution, whereas the reaction with a solution of bromine to form dibromoacetonitrile is interpreted as taking place by nucleophilic attack of the alkyne itself. The intermediary formation of triplet HCCN by flash vacuum pyrolysis and photolysis (255 nm) of the azide in the gas phase and in solid argon matrices, respectively, was confirmed by IR spectroscopy and mutual photo-interconversion of HCCN with isomeric cyclo-C(H)CN (azirinylidene) and HCNC by selective irradiations at 16 K. Although azidoacetylene is highly explosive, it can be irradiated in an argon matrix to generate cyanocarbene. The same species is also formed and analyzed after flash vacuum pyrolysis under relatively mild conditions. Decomposition of the azide in solution is combined with trapping reactions. Copyright

Flash vacuum thermolysis (FVT) of 1-methyl-5-phenyltetrazole (5b), 2-methyl-5-phenyltetrazole (1b), and 3-methyl-5-phenyl-1,3,4-oxadiazol-2(3H)-one (3b) affords the nitrile imine (2b), which rearranges in part to N-methyl-N′-phenylcarbodiimide (7b). Another part of 2b undergoes a 1,4-H shift to the diazabutadiene (13). 13 undergoes two chemically activated decompositions, to benzonitrile and CH2=NH and to styrene and N 2. FVT of 2,2-dimethyl-4-phenyl-oxazol-5(2H)-one (16) at 400 C yields 3-methyl-1-phenyl-2-azabutadiene (18) in high yield. In contrast, FVT of 3,3-dimethyl-2-phenyl-1-azirene (21) at 600 C or 4,4-dimethyl-3-phenyl- isoxazolone (20) at 600 C affords only a low yield of azabutadiene (18) due to chemically activated decomposition of 18 to styrene and acetonitrile. There are two reaction paths from azirene (21): one (path a) leading to nitrile ylide (17) and the major products styrene and acetonitrile and the other (path b) leading to the vinylnitrene (22) and ketenimine (23). The nitrile ylide PhC -=N+=C(CH3)2 (17) is implicated as the immediate precursor of azabutadiene (18). FVT of either 3-phenylisoxazol- 5(4H)one (25) or 2-phenylazirene (26) at 600 C affords N-phenylketenimine (28). The nitrile ylide PhC-=N+=CH2 (30) is postulated as a reversibly formed intermediate. N-Phenylketenimine (28) undergoes chemically activated free radical rearrangement to benzyl cyanide. The mechanistic interpretations are supported by calculations of the energies of key intermediates and transition states.

IR diode laser spectroscopy was used to detect the products of HCNO (fulminic acid) photolysis at 248 nm. Five product channels are energetically possible at this photolysis wavelength: O + HCN, H + (NCO), CN + OH, CO + NH, and HNCO. In some experiments, isotopically labeled 18O2, 15N18O and C2D6 reagents were included into the photolysis mixture in order to suppress and/or isotopically label possible secondary reactions. HCN, OC18O, C18O, NCO, DCN, and NH molecules were detected upon laser photolysis of HCNO/reagents/buffer gas mixtures. Analysis of the yields of product molecules leads to the following photolysis quantum yields: 1a (O + HCN) = 0.39 ± 0.07, 1b (H + (NCO)) = 0.21 ± 0.04, 1c (CN + OH) = 0.16 ± 0.04, 1d (CN + NH(a1Δ)) = 0.19 0.03, and 1e (HNCO) = 0.05 ± 0.02, respectively. The uncertainties include both random errors (1σ) and consideration of major sources of systematic error. In conjunction with the photolysis experiment, the H + HCNO reaction was investigated. Experimental data demonstrate that this reaction is very slow and does not contribute significantly to the secondary chemistry.

The "element effect" in nucleophilic aromatic substitution reactions (SNAr) is characterized by the leaving group order, L = F > NO2 > Cl ≈ Br > I, in activated aryl substrates. A different leaving group order is observed in the subs

The three isomeric pyridyl radicals 2a-c were synthesised using flash vacuum pyrolysis in combination with matrix isolation and characterised by infrared spectroscopy. The IR spectra are in good agreement with spectra calculated using density functional theory methods. The reaction of the pyridyl radicals 2 with molecular oxygen leads to the formation of the corresponding pyridylperoxy radicals 3a-c. The peroxy radicals 3 are photolabile, and irradiation results in syn-anti isomerisation of 3a and 3b and ring expansion of all three isomers of 3.