460-19-5

The adsorption and decomposition of C2N2 and CH3NH2 on Rh(111) have been studied by using temperature-programmed desorption (TPD) and Auger electron spectroscopy (AES).Both molecules adsorb readily on Rh(111) at 300 K and totally decompose.At very low cov

Pulsed laser photolysis of C2N2 at 193 nm has been used as a source of CN radicals in both the ν = 0 and ν =1 levels.Individual rovibronic levels of these radicals were measured as a function of time with a tunable dye laser.From these measurements the rate constants for the reaction of each of these vibrational levels with Hz, O2, CO, CO2, N2, HCN, C2N2, and CH4 have been determined.Some enhancement in the rate constant with vibrational energy which could not be ascribed to quenching was observed for O2, CH4, and H2.Only vibrational quenching was observed for HCN, N2, CO2, CO, and C2N2.In the CO case the vibrational quenching rate appears to be significantly enhanced by complex formation during the quenching process.

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The kinetics and mechanism of the decomposition of the tetracyanocuprate(II) ion (CuII(CN)42-) have been investigated by ESR measurements.Aqueous solutions of potassium cyanide with a small amount of copper(I) cyanide were electrolyzed in a cell the platinum anode of which was set in the resonant cavity of an ESR spectrometer.Since CuII(CN)42-, which is formed as an intermediate, gives a definite ESR spectrum, its concentration in the anode compartment is estimated from the intensity of the first-derivative spectrum at a fixed magnetic field.From the decay curves of the ESR intensity after the steady-state electrolysis currents have been switched off, a rate equation for the decomposition of CuII(CN)42- is derived; v = k0II(CN)42->2/->2, where k0 is calculated to be 74 mol*dm-3*s-1 at 25 deg C.This rate equation is also confirmed by ESR measurements during steady-state electrolysis, where the value of k0 = 60 mol*dm-3*s-1 is obtained.On the basis of the kinetics, two possible mechanisms are proposed: the formation of CuII(CN)3-, followed by the rate-determining bimolecular reaction of CuII(CN)3- to give 2CuI(CN)2- + (CN)2 (Mechanism A), and the formation of a binuclear complex, CuII2(CN)62-, followed by the rate-determining decomposition of CuII2(CN)62- to give 2CuI(CN)2- + (CN)2 (Mechanism B).The kinetics and the mechanism are compared with those of the chemical reaction between the copper(II) ion and the cyanide ion.

Thermal decomposition of hexaamminecobalt(III) hexacyanoferrate(III) (1) and hexaamminecobalt(III) hexachloroferrate(III) (2) in air as well as in nitrogen atmosphere was studied by using Moessbauer spectroscopy, TGA, DTA, IR spectroscopy, and magnetic susceptibility measurement. 1, when heated in air, is stable up to 200 deg C and then converted into hexacyanoferrate(II) and finally to ferrites; in inert atmosphere iron metal and carbides are formed above 400 deg C. 2 in air is reduced to iron(II) species and finally to ferrites; in inert atmosphere ligand exchange takes place forming cobalt(II) chloride.A mechanism is proposed for the decompositions of 1 and 2.

Auricyanide [Au(CN)4]- interaction with biologically important thiols, thioether and selenoether were carried out and monitored using 1H, 13C NMR and UV spectroscopy. These ligands include l-cysteine, glutathion

Photocatalytic aerobic oxidation of alcohols for the direct synthesis of esters has received significant attention in recent years, but the relatively low efficiency and selectivity under visible light irradiation is the main challenge for their practical applications. Here, surface acidic sites were imparted onto metal-free heterogeneous photocatalysts by the protonation of carbon nitride (HMCN) to promote the activity for the esterification reaction through further adsorption and activation of the intermediate aldehyde. The activation of the substrate could be remarkably modulated through tuning the acidic sites on the surface of the photocatalyst, leading to a controllable reactivity of the catalytic reaction. The one-pot process for the direct aerobic oxidative esterification of alcohol exhibits high efficiency and selectivity under mild and additive-free conditions and the apparent quantum yield (AQY) of the photocatalytic esterification reaction is 0.41% at 420 nm. Moreover, a scalable photocatalytic process by the merging of a continuous flow system with the heterogeneous HMCN photocatalyst is demonstrated, combining high catalytic efficiency and stability at ambient temperatures and being promising for larger-scale applications.

Herein we present the synthesis and characterization of di-tertiary butyl substituted (pseudo-)halogen bismuthanes tBu2BiX (X = Cl (1), Br (2), I (3), CN (4), N3 (5), SCN (6)). These compounds were obtained via different reaction paths. Compound 1 was obtained by a Grignard reaction of BiCl3 with two equivalents of tBuMgCl, whereas compounds 2, 3, 4 and 6 were synthesised by a oxidative addition/reductive elimination pathway starting from tBu3Bi and X2 (X = Br, I, CN, SCN). Finally, azide 5 was obtained by the reaction of 1 and NaN3. Secondary bonding interactions in the solid state within all the investigated compounds (1-6) cause additional stabilisation. Starting from tBu2BiCl, the completely tbutyl substituted ternary interpnictogen compound tBu2Bi(tBuP)SbtBu2 (7) was synthesized through the reaction with [tBu2SbP(tBu)Li(Et2O)]2. All new compounds were characterized by means of X-ray diffraction and mass spectrometry as well as NMR and IR spectroscopy.

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

Targeted as an example of a compound composed of a carbon atom together with two stable neutral leaving groups, 7-isocyano-7-azadibenzonorbornadiene, CN2A (1, A = C14H10 or anthracene) has been synthesized and spectroscopically and structurally characterized. The terminal C atom of 1 can be transferred: mesityl nitrile oxide reacts with 1 to produce carbon monoxide, likely via intermediacy of the N-isocyanate OCN2A. Reaction of 1 with [RuCl2(CO)(PCy3)2] leads to [RuCl2(CO)(1)(PCy3)2] which decomposes unselectively: in the product mixture, the carbide complex [RuCl2(C)(PCy3)2] was detected. Upon heating in the solid state or in solution, 1 decomposes to A, N2 and cyanogen (C2N2) as substantiated using molecular beam mass spectrometry, IR and NMR spectroscopy techniques.

When performed in the presence of cyanide and at pH smaller than 5, the RuO4-mediated oxidation of secondary amines Bn-NH-R (1a-b; R=Me, Et) gave mainly 1-cyanoformamidines Bn-NR-C(=NH)-CN (2a-b) and their hydrolysis products Bn-NR-COCN (3a-b), Bn-NR-CN (4a-b), Bn-NR-CONH2 (5a-b). Carboxamides 5a-b can result also directly from 1a-b. (Chemical Equation Presented).

Reactions of laser-ablated U atoms with (CN)2 produce UNC, U(NC)2, and U(NC)4 as the major products, identified from their Ar matrix infrared spectra and precursors partially and fully substituted with 13C and 15N. Mixed isotopic multiplets substantiate product stoichiometries. Band positions and quantum chemical calculations verify the isocyanide bonding. This journal is

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

A dielectric gaseous compound which exhibits the following properties: a boiling point in the range between about ?20° C. to about ?273° C.; non-ozone depleting; a GWP less than about 22,200; chemical stability, as measured by a negative standard enthalpy of formation (dHf0); a toxicity level such that when the dielectric gas leaks, the effective diluted concentration does not exceed its PEL; and a dielectric strength greater than air.

The reactions of cyanogen with Te6[AsF6]4 and Te4[AsF6]2 in SO2 solutions yield Te6[AsF6]4.1.5C2N2 (1) and Te4[A

[Zn(NCCN)6][AsF6]2 (1) was prepared either by dissolving [Zn(SO2)6](Te6)[AsF 6]6 in a SO2/(CN)2 mixture, or by the reaction of [Zn(AsF6/sub

Aminocyanophthalocyanine derivatives of the formula PcM.(CN).(NH3), in which PcM represents: wherein each R independently represents a substituent; each n independently represents an integer from 0 to 4; and M represents Co, Fe, Mn or Cr; also claimed is a process for preparation of aminocyanophthalocyanine cobalt derivatives and the use of the derivatives to obtain conductive polymers.

The preparation of Se(CN)4 was attempted by the reaction of SeF4 with Me3SiCN at low temperatures. However, selenium tetracyanide could not be detected by NMR spectroscopy; instead, the decomposition product Se(CN)2/

The photochemistry of CO(CN)2 in cryogenic matrixes has been investigated employing pulsed laser excitation at 193 nm. During irradiation, the parent molecule, the intermediate, and the final photoproducts were monitored by IR spectroscopy. Four new species were identified including the isocyano isomer of the parent NCC(O)-NC, cyanogen NCCN, isocyanogen CNCN, and CO according to spectroscopic features and ab initio calculations. After prolonged irradiation, the only remaining species were CO and the two isomers NCCN and CNCN. A reaction scheme is proposed which is in agreement with the first dissociation step being a branching of the decay path into the radical channel to CN + OCCN and the molecular channel to CO + (CN)2. The caged radicals of the former reaction either recombine to the parent molecule and its isomer which are both photolyzed again or they react directly to the stable and final products.

The so far unknown lead tricyanomethanide, Pb[C(CN)3] 2, was obtained from a saturated aqueous solution of PbCl2 and solid AgC(CN)3. Its IR spectrum and thermal behaviour are described. The crystal structure was determined by single-crystal X-ray diffraction (trigonal, P31m, Z = 3, a = 1414.4(5), c = 409.02(6) pm, R 1 = 0.0249, wR2 = 0.0527). Two crystallographically independent ninefold coordinated Pb atoms are connected by planar tricyanomethanide ions in two distinct bridging coordination modes. The Pb-N distances range between 254 and 293 pm.

The adsorption of HCN and the reaction of HCN with NO2 over Na-, and Ba-Y,FAU zeolite catalysts were investigated using in situ FTIR and TPD/ TPR spectroscopies. Both catalysts adsorb HCN molecularly at room temperature, and the strength of ads

The adsorption geometry of CN on Cu(111), both with and without predosing with oxygen, has been investigated using N K-edge near-edge X-ray absorption fine structure (NEXAFS) and C 1s and N 1s scanned-energy mode photoelectron diffraction (PhD). The NEXAFS shows clearly that adsorbed onto clean Cu(111) the C-N axis is closely parallel to the surface, but in the presence of coadsorbed oxygen the average orientation has the axis tilted by 25° away from the surface; this confirms a much earlier report of an oxygen-induced reorientation of CN on this surface based on vibrational spectroscopy. The PhD data show very weak modulations which are rather insensitive to the emission geometry, clearly implying a high degree of disorder or a local adsorption site well-removed from any position of high point group symmetry. The best-fit structure corresponds to the CN lying slightly displaced from the three-fold coordinated hollow sites but with the C and N atoms having single Cu atom nearest neighbours at distances of 1.98±0.05 and 2.00±0.05 A? respectively.

Information on azimuthal molecular orientation as well as on the tilt of the C-N molecular axis on the Pd(110) surface was derived by combining angle-dependent NEXAFS and full-solid-angle PED measurements. NEXAFS data and PED yield independent and consistent conclusions, indicating a nearly parallel CN adsorption on Pd(110), with preferential azimuthal orientation of the C-N molecular axis along the [001] direction. Furthermore, the presence of a 25° tilt of the C-N axis from the surface plane was found with the C atoms closer to the surface than N ones. While the near-parallel bonding geometry of CN found by previous ARUPS data was confirmed, the azimuthal orientation of the bond axis contradicted the conclusions based on the interpretation of photoemission data.

The adsorption of cyanogen on clean and oxygen pre-treated graphite supported copper films, and a polycrystalline copper surface, and the co-adsorption of cyanogen and oxygen on graphite supported copper films, and a polycrystalline copper surface has been studied using X-ray photoelectron spectroscopy. Cyanogen dissociates on the copper surfaces at 300 K, yielding an adsorbed cyano group, CN(a). On the oxygen pre-treated copper surface cyanogen reacts quantitatively with the adsorbed oxygen at 300 K to form a surface cyanate species, NCO. On annealing to 600 K this species decomposes, leaving only N adatoms and residual adsorbed CN on the surface. The co-adsorption of cyanogen and oxygen from a cyanogen-oxygen mixture enhances the formation of NCO to the extent that all available surface oxygen is consumed to form NCO on annealing at 450 K. In the absence of available atomic surface oxygen NCO does not decompose at temperatures up to 600 K. NCO and NCO2 are shown to be the intermediates in the oxidation of cyanogen on copper films and a polycrystalline copper foil.

New results are presented on the thermal stability of the primary explosive, the potassium salt of 4,6-dinitrobenzofuroxan (KDNBF) and on the mechanism of its decomposition. The new work complements and extends previous work done in our laboratory. The thermal decomposition of KDNBF has now been studied using a wide variety of experimental techniques: differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), accelerating rate calorimetry (ARC), heat flow calorimetry (HFC) and simultaneous thermogravimetry-differential thermal analysis (TG-DTA). The latter technique is coupled in our laboratory to FTIR and mass spectrometers to provide a very powerful method where the reaction products, the mass change and the temperature difference between the sample and reference can be monitored simultaneously as the material is decomposed. The results demonstrate that the decomposition takes place by a multi-step exothermic process directly from the solid state. The initial decomposition process does not appear to depend on the nature of the atmosphere, or the total pressure. The main gaseous product of the decomposition is carbon dioxide, with water, nitrous oxide and cyanogen also being formed. Kinetic parameters measured for the decomposition using a number of different techniques are in good agreement over eight orders of magnitude. An average of the available data gives: ln(k/min-1) = (41.2 ± 5.7) - ((170 ± 22) kJ mol-1)/RT. Although sensible Arrhenius data were generated, it was demonstrated that the mechanism of the decomposition is far from simple. For example, if KDNBF is thermally aged, its onset temperature can be decreased significantly, demonstrating that substantial changes to the material can occur well below its apparent decomposition temperature. The sensitivity of KDNBF to impact, friction and electrostatic discharges was also established. The results are compared to those available in the literature for KDNBF and for other primary explosives. Crown Copyright

Kinetic studies of X- exchange on [AuX4]- square-planar complexes (where X=Cl- and CN-) were performed at acidic pH in the case of chloride system and as a function of pH for the cyanide one. Chloride NMR study (330-365 K) gives a second-order rate law on [AuCl4]- with the kinetic parameters: (k2Au,Cl)298=0.56±0.03 s-1mol-1kg; ΔH2?Au,Cl=65.1±1 kJmol-1; ΔS2?Au,Cl=-31.3±3 Jmol-1K-1 and ΔV2?Au,Cl=-14±2 cm3mol-1. The variable pressure data clearly indicate the operation of an Ia or A mechanism for this exchange pathway. The proton exchange on HCN was determined by 13C NMR as a function of pH and the rate constant of the three reaction pathways involving H2O, OH- and CN- were determined: k0HCN,H=113±17 s-1, k1HCN,H=(2.9±0.7)×109 s-1mol-1kg and k2HCN,H=(0.6±0.2)×106 s-1mol-1kg at 298.1 K. The rate law of the cyanide exchange on [Au(CN)4]- was found to be second order with the following kinetic parameters: (k2Au,CN)298=6240±85 s-1mol-1kg, ΔH2?Au,CN=40.0±0.8 kJmol-1, ΔS2?Au,CN=-37.8±3 Jmol-1K-1 and ΔV2?Au,CN=+2±1 cm3mol-1. The rate constant observed varies about nine orders of magnitude depending on the pH and HCN does not act as a nucleophile. The observed rate constant of X- exchange on [AuX4]- are two or three orders of magnitude faster than the Pt(II) analogue.

The interaction of cyanogen with graphite and graphite supported copper film surfaces was investigated using x-ray photoelectron spectroscopy (XPS). It was found that on both the surfaces an Al Kα x-ray source induced a modification of condensed cyanogen overlayers. The results suggested that modification was x-ray induced polymerization formed via an indirect mechanism involving secondary electrons from the substrate.

Single crystals of M(SCN)2 (M = Eu, Sr, Ba) have been obtained via metathesis of NaSCN and MCl2 (M = Eu, Sr, Ba) at 340°C. The isotypic crystal structures of the thiocyanates M(SCN)2 (C2/c, Z = 4, Eu: a = 979.3(2), b = 660.8(1), c = 815.7(2) pm, β = 91.58(3)°, Rall = 0.0245, Sr: a = 985.5(2), b = 662.9(2), c = 819.6(2) pm, β = 91.29(3)°, Rall = 0.0435, Ba: a = 1018.8(2), b = 687.2(1), c = 852.2(1) pm, β = 92.43(2)°, Rall = 0.0392) contain alternating layers of M2+ and SCN-. According to M(SCN)4/4(NCS)4/4 M2+ is eight-coordinated by four sulfur and four nitrogen atoms forming a square antiprism. Thermal investigations show that the compounds melt without decomposition. Vibrational spectroscopic investigations are presented and discussed. WILEY-VCH Verlag GmbH, 2001.

The first known paramagnetic, tetrahedral cyanide complex, [MnII(CN)4]2-, is formed by the photoinduced decomposition of [MnIV(CN)6]2- in nonaqueous solutions or by thermal decomposition in the solid state. In acetonitrile or dichloromethane, photoexcitation into the ligand-to-metal charge transfer band (λmax = 25 700 cm-1, ε = 3700 cm-1 M-1) causes the homolytic cleavage of cyanide radicals and reduction of MnIV. Free cyanide in dichloromethane leads to the isolation of polycyanide oligomers such as [C12N12]2- and [C4N4]-, which was crystallographically characterized as the PPN+ salt C40H30N5P2: monoclinic space group = 12/a, a = 18.6314(2) A, b = 9.1926(1) A, c = 20.8006(1), β = 106.176(2)°, Z = 4]. In the solid state MnIV-CN bond homolysis is thermally activated above 122 °C, according to differential scanning calorimetry measurements, leading to the reductive elimination of cyanogen. The [MnII(CN)4]2- ion has a dynamic solution behavior, as evidenced by its concentration-dependent electronic and electron paramagnetic spectra, that can be attributed to aggregation of the coordinatively and electronically unsaturated (four-coordinate, 13-electron) metal center. Due to dynamics and lability of [MnII(CN)4]2- in solution, its reaction with divalent first-row transition metal cations leads to the formation of lattice compounds with both tetrahedral and square planar local coordination geometries of the metal ions and multiple structural and cyano-linkage isomers. α-MnII[MnII(CN)4] has an interpenetrating sphalerite- or diamond-like network structure with a unit cell parameter of a = 6.123 A (P43m space group) while a β-phase of this material has a noninterpenetrating disordered lattice containing tetrahedral [MnII(CN)4]2-. Linkage isomerization or cyanide abstraction during formation results in α-MnII[CoII(CN)4] and MnII[NiII(CN)4] lattice compounds, both containing square planar tetracyanometalate centers. α-MnII[CoII(CN)4] is irreversibly transformed to its β-phase in the solid state by heating to 135 °C, which causes a geometric isomerization of [CoII(CN)4]2- from square planar (vCN = 2114 cm-1, S = 1/2) to tetrahedral (vCN = 2158 cm-1, S = 3/2) as evidenced by infrared and magnetic susceptibility measurements. MnII[NiII(CN)4] is the only phase formed with NiII due to the high thermodynamic stability of square planar [NiII(CN)4]2-.

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.

The synthesis of crystalline Be(CN)2 and Mg(CN)2 has been demonstrated and X-ray diffraction studies indicate simple-cubic structures with four-coordinate metal atoms surrounded by an average of two N and two C atoms. The symmetry of Be(CN)2 is Pn3m, a = 5.339(1) A, Z = 2. The symmetry of Mg(CN)2 is also Pn3m, a = 6.122(1) A, Z = 2. A thallium cyanide with composition Tl(CN)2 was prepared and was shown to have a similar simple-cubic structure with a = 6.660(1) A. On the basis of the X-ray diffraction pattern, IR spectra, and combustion analysis, this material is assigned the formula TlITlIII(CN)4. Crystalline Al(CN)3 with simple-cubic structure has been prepared for the first time. Rietveld refinement indicated that the structure incorporates CN groups with orientational disorder in a Prussian-blue-like octahedral network. 27Al NMR spectroscopy confirmed C,N disorder in cubic Al(CN)3. The symmetry for Al(CN)3 is Pm3m, a = 5.205(1) A.

The interaction of cyanogen with (100) Ni surfaces at room temperature was studied using secondary ion mass spectrometry in a static mode, and photoemission spectroscopies (XPS and UPS). It has been shown that cyanogen is adsorbed on this nickel surface in a dissociative mode: atomic carbon and nitrogen are present on the surface as well as CN fragments. These adsorbed species have been characterized by XPS and UPS. Increasing the temperature in the 400 K range increases the rate of the dissociation reaction of CN into atomic carbon and nitrogen. Moreover carbon is found to dissolved into the bulk for temperatures as low as 475 K. No evidence has been found of a polymerized form of cyanogen molecules on this nickel surface, when the temperature is increased unlike the results obtained for the (111) Ni surface.

The formation and stability of CN adlayers on Rh(110), formed by dissociative adsorption of C2N2 at 373 K, have been studied as a function of coverage and temperature by low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), and thermal desorption spectroscopy (TDS). Two different CN adsorption states have been distinguished by their different C 1s and N 1s XPS core-level binding energies. The CN-I state is exclusively occupied up to a surface coverage of 0.5 monolayers (ML), where a well-ordered c(2 x 2) LEED pattern is observed. The CN-II state becomes additionally populated at higher coverages from 0.5 ML to the saturation coverage of 0.87 ML. At CN saturation, a c(4 x 2) LEED structure is formed. Desorption of CN as molecular C2N2 occurs only for surface coverages >0.5 ML and appears to be mainly derived from the CN-II state. The onset of C-N bond rupture is indicated at ～450-550 K, depending on the CN coverage; the resulting Nad desorbs at ～580 K from the more crowded surface and in the range of ～650-950 K, whereas Cad remains at the Rh surface and cannot be desorbed thermally.

The structure and properties of the thermal decomposition products of Fe[Fe(CN)5NO] · x H2O (x = 5～6) have been studied by Moessbauer and FT-IR spectroscopy, X-ray diffraction and conductivity measurements. The valence state and coordination environment of the iron ions change dramatically when the nitrosyl ligand is eliminated by heat-treatment under vacuum at 200 °C. The dark blue product obtained by heat-treatment under vacuum at 250 °C is characteristic of the mixed-valence state in Prussian blue analogues. The electrical conductivity of the dark blue product is higher by a factor of 103 than that of the starting material because of the mixed-valence state between Fe(III)[Fe(II)(CN)5] and Fe(II)[Fe(III)(CN)5]. Heat-treatment under vacuum at 350°C yields a new product Fe(II)[Fe(II)(CN)4] the crystal structure of which is different from that of the starting material. The electrical conductivity of the decomposition product obtained at 350 °C is about 105 times higher than that of the starting material.

Dicyanogen, NCCN, is generated for spectroscopic investigations on-line from rubeanic acid, mercury(II) cyanide, and cyanogen iodide and studied in the gas phase by two-dimensional Penning and He I photoelectron spectroscopies, as well as ab initio calculations. From spectroscopic data, the interaction between NCCN and He*(23S) atoms is deduced. The interaction potential for the similarly interacting NCCN-Li(22S) system is obtained from ab initio calculations at the CCSD/6-311++G** level. Experimental and calculated results show that the interaction potential is anisotropic around NCCN, is the most attractive in the nitrogen lone electron pair region, and gradually changes into repulsive as the N-C-He*(or Li) angle opens up to 90°. An unusual collision energy dependences of the partial ionization cross sections are observed, which is interpreted by the unusual interaction potential. For assisting experimental data and studying collision dynamics, classical trajectory calculations are performed for the Penning ionization of the NCCN-He*(23S) system. The spectroscopic investigations predict the existence of thermodynamically stable MLi radicals, and the structure and stability of NCCNLi isomers are calculated at the QCISD/6-311++G** level.

The photodissociation of carbonyl cyanide CO(CN)2 at 193 nm was investigated by photofragment translational energy spectroscopy. For all the fragments created (CO, CN, OCCN, NCCN), the kinetic energy distributions were measured and two decay channels identified. The radical decay, CO(CN)2 + hν→OCCN+CN, dominates with a yield of 94%±2% and shows the available energy mainly (82%) channeled into the internal degrees of freedom of the fragments. A fraction of 18%±6% of the nascent OCCN radicals has sufficient energy to spontaneously decay to CO+CN involving a barrier ≤160 kJ/mol. With a yield of 6%±2% the molecular decay produces the fragments CO+NCCN. These fragments acquire a high available energy owing to the formation of the new C-C bond in NCCN. An average fraction of 70% is partitioned into internal fragment energy. Even the fastest fragments are still internally hot, indicating that with the high barrier expected, a substantial exit channel interaction is operative. The isotropic recoil distribution found for the products CN, OCCN, and NCCN further suggests that both the radical and the molecular decay are, on the time scale of a parent rotation, slow and probably indirect.

The vibrational Raman spectra of cyanogen have been obtained in the gas, liquid and solid states. The three Raman active fundamentals, ν1, ν2 and ν4, have been identified in all three phases; whereas the spectra are consistent with D(∞h) molecular symmetry for the gaseous and liquid phases, the solid state spectrum clearly shows the presence of the infrared active and Raman-forbidden ν3 mode. This is possibly indicative of a breakdown of the centro-symmetric structure in the solid state in contradiction of the X-ray diffraction results.

Thermal decomposition of dinitramide onium salts proceeds via the dissociative mechanism when pKa of the base is lower than 5.0 and via the monomolecular decay of the anion at pKa > 7.0. On going from the melt to the solid state, the reaction mechanism does not change, and the rate decreases by 1-2 orders of magnitude. No anomalous effects inherent in dinitramide metal salts in the solid phase are observed during decomposition of onium salts.

Ultraviolet-visible and IR spectroscopy and mass spectrometry have been used to investigate photolysis of the (2-) ion upon irradiation with UV/VIS light in aqueous solutions and in poly(vinyl alcohol) films at 12 and 298 K.Changes in the ν(CN) and ν(NO) bands in the IR and in the d-d and charge-transfer bands in the UV/VIS region were used to monitor the appearance and disappearance of complex ions as a function of photolysis time.Mass spectrometric analysis of the gaseous products released during the irradiation of aqueous solutions revealed NO, HCN, and (CN)2.The combined results showed that the (2-) ion undergoes photoaquation and photoreduction, producing aquacyanoferrate-(III) and -(II) species.The origin of the iron(II) species was shown to be mainly due to the photoreduction of the iron(III) species produced after primary loss of the nitrosyl ligand as molecular NO and not as NO(1+).Subsequent thermal reactions between the iron-(II) and -(III) species led to the formation of mixed-valence compounds, e.g.Prussian blue.A scheme for the photochemical and thermal reactions with CN(.), CN(1-) and NO loss pathways is proposed.The possible implications of the results for the use of (2-) as a vasodilator are discussed.

Ambient light photolysis of gaseous BrCN, ClCN, and ICN results in the production of isocyanogen (NCNC) as the sole CN containing product. The flash vacuum pyrolysis of BrCN (1100°C and E-5 mbar) generates NCNC, NCCN, HOCN, HNCO and the CN radical.

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The thermal decomposition of benzotrifuroxane proceeds through cleavage of the C-C and O-N(O) bonds of the furoxane ring with formation of dinitriloxodifuroxanyl.

We report the results of a room temperature selected ion flow tube study of reactions of HCN+ and HNC+. Electron impact on HCN was found to produce a mixture of HCN+ and HNC+ isomers. HCN+ was found to be isomerized efficiently to HNC+ by reaction with CO or with CO2, and isomerization is expected to occur for any other species M having a proton affinity PA(CN at C) a forth and back proton transfer mechanism. A monitor gas technique was used to distinguish between the isomers. With CF4, HCN+ was reactive (k = 1.2 × 10-9 cm3 s-1) and HNC+ unreactive. With SF6 both isomers react at the collision rate but HCN+ yields only SF5+ as the product ion whereas HNC+ yields only HNCF+. Thermodynamic data established in this work include Δr(HNC+) ≤ 1373 kJ mol-1, and hence PA(CN at N) ≥ 595 kJ mol-1.

A convenient laboratory scale preparation of cyanogen has been developed.This new method generates cyanogen from the pyrolysis of diacetylglyoxime which can be easily prepared from glyoxime.

Piperidinium hexathiocyanatochromate(III), (pipH)3[Cr(NCS)6], was synthesized using the molten salt pipHSCN and was found to contain nitrogen-bonded thiocyanate. The (pipH)3[Cr(NCS)6] decomposes in the range 250

The adsorption and decomposition of CH3NO2 and C2H5NO2 on Rh(111) and C2H5NO2 an Pt(111) have been studied by using temperature-programmed desorption (TPD) and Auger electron spectroscopy (AES).TPD following adsorption of CH3NO2 on Rh(111) produces comple

Absolute rate constants were obtained for CN (X 2Σ+) radical reactions with HCN, BrCN and CH3CN. The CN radical relative concentration was followed by laser-induced fluorescence (LIF) with a cw ring dye laser on the A 2Π-X 2Σ+ (4, 0) band at 621.5 nm. CN radicals were generated by laser photolysis of ICN at 266 nm. The following Arrhenius parameters were obtained over the temperature range 296-578 K: CN+HCN, k=10-11.41±0.15 exp[-(670±100)/T] cm3 s-1; CN+BrCN, k=10-10.7±0.4 × exp[-(1340±330)/T] cm3 s-1; CN+CH3CN, k=10-10.19±0.10 exp[-(1190±70)/T] cm3 s-1. The rates meas and that of Szekely et al. for CN+HCN could be well fitted by the form, k=10-16.20T1.57 exp (-50/T) cm3 s-1 over the range 300-3000 K, allowing extrapolation to the combustion temperature regime. The measured rates and those of Kayes and Levitt and Clark et al. for the CN+BrCN reaction could be fitted by the form, k=10-14.18T1.16 exp(-940/T) cm3 s-1 the temperature range 300-3000 K. In addition, the non-linearity of these data over a wide range of temperature could be satisfactorily accounted for by transition-state theory calculations for both of these reactions.

The new compound K can be prepares by addition of one formula unit of iodine to a concentrated aqueous solution of two mole equivalents of potassium cyanide.It crystallizes in the monoclinic space group C2/m with a = 736.4, b = 451.4, c = 908.0 pm, β = 92.56 deg and Z = 2.The crystal structure has been refined to Rf = 0.020 for 301 observed reflections.The structure may be described as a layer-like package of cations K(+) and trihalide-analogous anions (-).The anions are strictly linear at the I atoms (symmetry 2/m) and nearly linear at the C atoms with φ(I-C-N) = 178.6 deg and d(I-C) = 229.8, d(C-N) = 112.9 pm.The cation is surrounded by a slightly distorted octahedron of nitrogen atoms with d(K***N) = 284.8, 292.6 pm. - Keywords: Potassiumdicyanoiodate, Cyanogen Compound, Polypseudohalide, Pseudotrihalide, Crystal Structure

Cyanogen chloride was condensed at 12 K with HF in excess argon, producing two 1:1 complexes of the form ClHN--HF (1) and HF--ClCN (2).Increasing the HF concentration produced a 1:2 complex, ClCN--(HF)2, while increasing the ClCN concentration produced a 2:1 complex, ClCN--HF--ClCN.The HF submolecule stretching frequency for the major primary 1:1 complex (1) was observed at 3597 cm-1, and a single HF liberational mode appeared at 602 cm-1.These fundamentals are comparable to the HF modes for alkyl cyanide complexes.In sharp contrast, the second 1:1 complex (2), which is similar to the HF--ClF and HF--Cl2 complexes, displayed a HF stretching frequency at 3912 cm-1.Similarresults were obtained for cyanogen bromide and cyanogen iodide complexes with hydrogen fluoride and deuterium fluoride.In addition, the photolysis of hydrogen cyanide and fluorine produced the complex FCN--HF with no evidence for a complex analogous to 2.The HF stretching and liberational modes for this complex were observed at 3662 and 553 cm-1, respectively.Similarly, the reaction between cyanogen and HF formed only the NCCN--HF complex.The HF modes for this complex were observed at 3757 and 460 cm-1, which indicate a weaker interaction than found for the cyanogen halides and HF.

Reactions of hydrocarbon and carbon/nitrogen ions with diacetylene and of the diacetylene radical cation with various molecules have been examined with a view to molecular growth by ion-molecule reaction.Measurements were performed with a Selected-Ion Flow Tube (SIFT) apparatus at 296 +/- 2 K of the rate constants and product distributions for the reactions of C+, CH3+, C2H2+, C3H+, CN+, C2N+, and C2N2+ with C4H2 and of C4H2+ with H2, CO, C2H2, C2N2, and C4H2.Condensation and association reactions which build up the carbon content of the ion were observed to compete with charge transfer.For the reactions of CN+ and C2N2+ with C4H2 this growth involved the addition of cyanide to the carbon chain.The kinetics of protonation of diacetylene were also investigated.It was possible to bracket the proton affinity of diacetylene between the known proton affinities of HCN and CH3OH with a value for PA(C4H2) = 177 +/- 5 kcal mol-1, which results in a heat of formation for C4H3+ of 305 +/- 5 kcal mol-1.Numerous secondary association reactions were observed to form adduct ions in helium buffer gas at total pressures of a few tenths of a Torr with rates near the collision rate.This was the case for C6H4+ (C4H2+*C2H2), C7H5+ (C3H3+*C4H2), C8H4+ (C4H2+*C4H2), C8H5+ (C4H3+*C4H2), C9H3+ (C5H+*C4H2), C9H4+(C5H2+*C4H2), C9H5+ (C5H3+*C4H2), C10H4+ (C6H2+*C4H2), C10H5+ (C6H3+*C4H2), C11H7+ (C3H3+*(C4H2)2), C12H6+ (C4H2+*(C4H2)2), C9H3N+ (HC5N+*C4H2), and C10H4N+ (C2N+*(C4H2)2) where the reactants are indicated in parentheses.The observed high rates of association imply the formation of chemical bonds in the adduct ions but the structures of these ions were not resolved experimentally.In most instances there seems little basis for preferring acyclic over cyclic adduct ions.

A systematic study about the electrochemical behaviour of the cyanide ions in molten dimethylsulfone medium at 127 degC using several electrodes has been carried out.The oxydation of cyanide ions on a platinum electrode in this medium leads to cyanogen which is a electrochemically inactive species in molten dimethylsulfone.The anodic oxydation at a silver electrode in the presence of cyanide ions give two waves.The first one is due to the formation of Ag(CN)2(1-) complex, and the second one is due to the formation of a solid product, Ag(CN).These electrochemical reactions are useful to determine the cyanide ions by a stripping chatodic method in the concentration level of 0.05 ppm.The anodic oxydation of gold amalgamated electrode in the presence of cyanide ions give several waves not well defined and finally the Hg(CN)2 complex.

Photoluses of HCN, C2H2, and mixtures were accomplished including various ratios of HCN/C2H2 and time periods.The photolysis of HCN yielded (CN)2, CH4, NH3, CH3NH2, (NH)2, and a brown polymer.The products from C2H2 were diacetylene (C4H2), C2H4, C6H6, vinylacetylene, phenylacetylene, and a polymer.Products from a relatively low HCN/C2H2 ratio (5:1) where 90percent of the light is absorbed by C2H2 were similar to those of C2H2 except for the additional formation of acrylonitrile (C2H3CN).At relatively higher ratios of HCN/C2H2 where 37-56percent of the light is absorbed by HCN, cyanoacetylene (C2HCN) was formed in addition to the foregoing products and the C4H2 substantially reduced.The proposed principal path for formation of C4H2 is attack of C2H. on C2H2, while for C2H3CN the principal path is attack of C2H3. on HCN.The proposed principal path for production of C2HCN is via CN. attack on C2H2.Several products from HCN are proposed to be the result of progressive H atom addition.Other products from C2H2 and HCN are the result of radical-radical recombination.We believe these results could have relevance to Jovian atmosphere chemistry and formation of several molecules found in interstellar space.