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A safe, fast procedure for the formation of chlorine azide and its trapping by 1,2-addition reaction on olefins is described. ClN3 was generated in situ from NaN3 and NaOCl in the presence of acetic acid, hosted in an organic phase to avoid decomposition and exposed to various alkenes. A copper-catalyzed click reaction then afforded triazoles from the resulting addition products. Telescoping of both reactions was enabled by an in-line workup and subsequent liquid–liquid separation.

The kinetics of eighteen positive ions with chlorine azide (ClN3) have been studied using a selected ion flow tube (SIFT). These measurements allowed for the estimation of both the ionization energy, >930 kJ mol−1 (>9.6 eV), and the proton affinity, 713 ± 41 kJ mol−1, of chlorine azide. Reaction rate constants have been determined. Product ions have been identified, and quantified when synthetic complications allowed. In addition, general reaction trends have been observed. A reaction coordinate diagram for the novel reaction of N+ with ClN3 is discussed.

High-resolution synchrotron-radiation-based photoionization mass spectrometry was applied to study the dissociative photoionization of ClN 3 under collision-free molecular beam conditions at ionization energies between 10 and 17 eV. No parent ion (ClN 3 + ) could be detected under our experimental conditions. This suggests that the ground and excited states of ClN 3 + are weakly bound or repulsive, a conclusion supported by electronic structure calculations also reported here. We recorded photoionization yield spectra at m / z = 49, 42, 35 and 14 from which we extracted the appearance potentials for NCl + , N 3 + , Cl + , and N + . The appearance potential of NCl + (10.17 ± 0.02 eV) observed here is close to the previously reported ionization potential of ClN 3 obtained form photoelectron spectroscopy. Using the theoretically calculated binding energy of ClN 3 + (0.2 eV), we derive an estimate of the adiabatic ionization potential of ClN 3 = 9.97 ± 0.02 eV. The measured appearance potentials for N 3 + , Cl + , and N + provide three independent determinations of the Cl–N bond energy in ClN 3 , which agree within their respective error limits. The observations of this work are consistent with a new value of the N–Cl bond energy in ClN 3 , D 0 (Cl–N 3 ) = 1.86 ± 0.05 eV, 0.3 eV lower than previously reported values, which are however experimentally derived upper limits. The bond energy reported here is consistent with high level ab initio (CCSD(T)) electronic structure calculations extrapolated to the complete basis set limit, which yield a value: D 0 (Cl–N 3 ) = 1.87 eV.

A biphasic media in the presence of olefinic compounds dissolved in the organic layer or in the absence of an organic layer avoids the formation of the explosive gaseous ClN3.

The in situ preparation and trapping of chlorine azide provided a versatile one-pot method for the azidochlorination of alkenes. Gaseous ClN3 generated from sodium azide, hypochlorite, and acetic acid can be explosive if isolation is attempted. Instead, we generated the reagent in biphasic media in the presence of olefinic compounds dissolved in the organic layer or evenly emulsified throughout the solution in the absence of organic solvent. Under these conditions, ClN3 is created slowly and trapped immediately at the aqueous-organic interface. The resulting safe and reliable procedure provided 1,2-azidochloride derivatives of a variety of substrates, with evidence for both polar and radical mechanisms. Minor impurities characterized in the product mixtures indicated the presence of alternative reaction pathways deriving primarily from radical intermediates.

The primary reaction products from 248-nm chlorine azide photolysis are identified in a collision-free experiment. In contrast to all previous reports, the radical channel producing Cl + N3 (95 � 3%) is seen to dominate the photochemistry. The molecular channel producing NCl + N2 (5 � 3%) was also observed. 2004 Elsevier B.V. All rights reserved.

The method of velocity map imaging was applied to study the photodissociation dynamics of ClN3 near 235 nm under collision-free conditions. Derived kinetic energy distributions of state-selected Cl (2PJ) provide a medium-resolution energy spectrum of the N3 fragment. Markedly bimodal distributions are observed that suggest simultaneous formation of the linear-N3 (X 2Π) isomer as well as an energetic form of N3, consistent with recent theoretical predictions of a cyclic isomer, resembling an isosceles triangle. Angular distributions of the photofragments indicate that 21A‘ ← 11A‘ excitation is the most important pathway to photoproducts. Branching ratio measurements between the dominant spin−orbit excited-state Cl* (2P1/2) and the spin−orbit ground-state Cl (2P3/2) showed Cl*/Cl ≈ 0.8/0.2. The branching ratio between linear-N3 and cyclic-N3 formation was determined to be ≈ 0.8/0.2.

A number of experiments have been performed in an effort to better understand the photoinitiated chain decomposition of ClN3. Discharge-flow methods were used to determine the rate of energy exchange between vibrationally excited N2 (a likely chain carrier) and ClN3. The rate constant for energy transfer from N2(v=1) to ClN3 was found to be (2.0 ± 1.0) × 10-13 cm3 s-1 at 300 K. This process is thought to excite the ν2 mode in ClN3 with the release of 281 cm-1 of excess energy. Experiments were also performed in which the decomposition of ClN3 was initiated by photolysis with a pulsed KrF laser at 249 nm, with subsequent observation of the time dependence of the densities of ClN3, electronically excited NCl(a1Δ), and vibrationally excited ClN3(ν2). A kinetic model for the ClN3 decomposition was assembled based on reactions with NCl(a1Δ) and N2(ν).

Kinetic measurements of NCl(a1Δ) metastables produced by the photolysis of chlorine azide (ClN3) at 193 nm are reported. High NCl(a1Δ) density (>1015 molecules/cm3) production facilitates measurements of the NCl(a1Δ) + NCl(a1Δ) self-annihilation rate. A gas phase transient chemical titration scheme is used to calibrate absolute NCl(a1Δ) density. The NCl(a1Δ) bimolecular rate coefficient at room temperature is (7.2 ± 0.9 × 10-12 cm3/(molecule s) and has a magnitude very critical to the development of an NCl(a1Δ) + I(2P3/2) → I*(2P1/2) + NCl(X3Σ-) chemical laser. Despite the large value of the self-annihilation rate, intense I*(2P1/2) emission via transfer from NCl(a1Δ) is strongly observed when mixtures of CH2I2 and ClN3 are photolyzed at 193 nm. Unlike the analogous O2(a1Δ) + I(2P3/2) energy transfer system, the relatively large NCl(a1Δ) bimolecular rate constant suggests that NCl(a1Δ) transport times must be short and will require small chemical mixing regions for efficient lasing. In addition, the 300 K...

International audience; We report the first time-resolved study of the photochemistry of chlorine azide (ClN3) by femtosecond velocity-map imaging (fs-VMI). The dissociation dynamics are initiated at 4.6 eV and the photofragments are detected by multiphoton ionization using an intense laser field centered at 803 nm. A dissociation time of 262 ± 38 fs was measured from the rising time of the co-fragments N3 and Cl. The time dependency of the angular distribution of N3, which converges from β2 ∼ 2 to β2 = 1.61 ± 0.07 in 170 ± 45 fs, reveals the parallel nature of the transition dipole moment.

Revealing the underlying ultrafast dynamics in molecular reaction spectroscopy demands state-of-the-art imaging techniques to follow a molecular process step by step. Femtosecond time-resolved velocity-map imaging is used to study the photodissociation dynamics of chlorine azide (ClN3). Here especially the co-fragments chlorine and N3 are studied on the femtosecond timescale in two excitation energy regions around 4.67 eV and 6.12 eV, leading to the formation of a linear N3 fragment and a cyclic N3 fragment, respectively. This work is the first femtosecond spectroscopy study revealing the formation of cyclic N3. Tetrathiafulvalene (TTF, C6H4S4) electronic relaxation is studied, while scanning the electronic excitation around 4 eV, by time resolved mass and photoelectron spectroscopy. As only few is known about the ion continuum about TTF the imaging photoelectron photoion coincidence (iPEPICO) technique is used in order to disentangle the complex ionic dissociation. The second part of the thesis is based on the generation and application of XUV light pulses by high-order harmonic generation with an intense femtosecond laser pulse in a molecular target. Two types of phase sensitive attosecond spectroscopy experiments were conducted to study the vibrational dynamics of SF6: one using strong field transient grating spectroscopy, where high-order harmonic generation takes place in a grating of excitation, and the second experiment using high-order harmonic interferometry using two intense XUV probe pulses. The temporal dependencies in phase and amplitude reveal the vibrational dynamics in SF6 and demonstrate that high-order harmonic generation is sensitive to the internal excitations. Last but not least, the use of high-order harmonics as a XUV photon source for the velocity-map imaging spectrometer is investigated. Using time-resolved photoelectron imaging, the relaxation dynamics initiated with 15.5 eV in argon and 9.3 eV in acetylene are revealed.; Dans cette thèse, la dynamique de photodissociation de l'azoture de chlore (ClN3) est étudiée dans le domaine temporel par imagerie de vecteur vitesse des photofragments, spécialement du chlore et de N3. Cette imagerie résolue à l'échelle femtoseconde permet d'extraire les temps de dissociation, l'établissement temporel de la balance d'énergie de la réaction ainsi que la conservation des moments. Cette étude a permis de différencier deux domaines d'énergie: l'un menant à la formation d'un fragment N3 linéaire (étude autour de 4.5 eV d'excitation électronique) et le plus intéressant aboutissant à la formation d'un fragment N3 cyclique (autour de 6 eV). Dans une seconde étude, la dynamique de relaxation électronique du tétrathiafulvalène (C6H4S4-TTF) est étudiée autour de 4 eV par spectroscopie de masse résolue en temps ainsi que par spectroscopie de photoélectron. Les seuils d'ionisation dissociative sont extraits d'une détection en coïncidence entre les photoélectrons de seuil et les fragments ionisés réalisée sur rayonnement synchrotron. Les deux dernières expériences sont basées sur la génération d'harmoniques d'ordre élevé dans l'XUV d'une impulsion femtoseconde à 800 nm ou à 400 nm. Dans la première expérience, les harmoniques sont couplées à un imageur de vecteur vitesse en tant que rayonnement secondaire VUV. Par imagerie de photoélectron résolue en temps, nous avons révélé ainsi les dynamiques de relaxation des états de Rydberg initiée par une impulsion femtoseconde XUV à 15.5 eV dans l'argon et à 9.3 eV dans l'acétylène. Dans la seconde expérience, couramment nommée spectroscopie attoseconde, les harmoniques constituent le signal pompe sonde. Deux types de spectroscopie attoseconde ont été réalisés pour étudier la dynamique vibrationnelle de SF6: une expérience en réseau transitoire créé par deux impulsions pompe Raman avec une impulsion sonde intense générant les harmoniques à partir du réseau d'excitation et une expérience d'interférence de deux rayonnement XUV en champ lointain créés par deux impulsions sonde intenses.

Revealing the underlying ultrafast dynamics in molecular reaction spectroscopy demands state-of-the-art imaging techniques to follow a molecular process step by step. Femtosecond time-resolved velocity-map imaging is used to study the photodissociation dynamics of chlorine azide (ClN3). Here especially the co-fragments chlorine and N3 are studied on the femtosecond timescale in two excitation energy regions around 4.67 eV and 6.12 eV, leading to the formation of a linear N3 fragment and a cyclic N3 fragment, respectively. This work is the first femtosecond spectroscopy study revealing the formation of cyclic N3. Tetrathiafulvalene (TTF, C6H4S4) electronic relaxation is studied, while scanning the electronic excitation around 4 eV, by time resolved mass and photoelectron spectroscopy. As only few is known about the ion continuum about TTF the imaging photoelectron photoion coincidence (iPEPICO) technique is used in order to disentangle the complex ionic dissociation. The second part of the thesis is based on the generation and application of XUV light pulses by high-order harmonic generation with an intense femtosecond laser pulse in a molecular target. Two types of phase sensitive attosecond spectroscopy experiments were conducted to study the vibrational dynamics of SF6: one using strong field transient grating spectroscopy, where high-order harmonic generation takes place in a grating of excitation, and the second experiment using high-order harmonic interferometry using two intense XUV probe pulses. The temporal dependencies in phase and amplitude reveal the vibrational dynamics in SF6 and demonstrate that high-order harmonic generation is sensitive to the internal excitations. Last but not least, the use of high-order harmonics as a XUV photon source for the velocity-map imaging spectrometer is investigated. Using time-resolved photoelectron imaging, the relaxation dynamics initiated with 15.5 eV in argon and 9.3 eV in acetylene are revealed.; Dans cette thèse, la dynamique de photodissociation de l'azoture de chlore (ClN3) est étudiée dans le domaine temporel par imagerie de vecteur vitesse des photofragments, spécialement du chlore et de N3. Cette imagerie résolue à l'échelle femtoseconde permet d'extraire les temps de dissociation, l'établissement temporel de la balance d'énergie de la réaction ainsi que la conservation des moments. Cette étude a permis de différencier deux domaines d'énergie: l'un menant à la formation d'un fragment N3 linéaire (étude autour de 4.5 eV d'excitation électronique) et le plus intéressant aboutissant à la formation d'un fragment N3 cyclique (autour de 6 eV). Dans une seconde étude, la dynamique de relaxation électronique du tétrathiafulvalène (C6H4S4-TTF) est étudiée autour de 4 eV par spectroscopie de masse résolue en temps ainsi que par spectroscopie de photoélectron. Les seuils d'ionisation dissociative sont extraits d'une détection en coïncidence entre les photoélectrons de seuil et les fragments ionisés réalisée sur rayonnement synchrotron. Les deux dernières expériences sont basées sur la génération d'harmoniques d'ordre élevé dans l'XUV d'une impulsion femtoseconde à 800 nm ou à 400 nm. Dans la première expérience, les harmoniques sont couplées à un imageur de vecteur vitesse en tant que rayonnement secondaire VUV. Par imagerie de photoélectron résolue en temps, nous avons révélé ainsi les dynamiques de relaxation des états de Rydberg initiée par une impulsion femtoseconde XUV à 15.5 eV dans l'argon et à 9.3 eV dans l'acétylène. Dans la seconde expérience, couramment nommée spectroscopie attoseconde, les harmoniques constituent le signal pompe sonde. Deux types de spectroscopie attoseconde ont été réalisés pour étudier la dynamique vibrationnelle de SF6: une expérience en réseau transitoire créé par deux impulsions pompe Raman avec une impulsion sonde intense générant les harmoniques à partir du réseau d'excitation et une expérience d'interférence de deux rayonnement XUV en champ lointain créés par deux impulsions sonde intenses.

The reaction behavior of NaN3, AgN3, and Me3SiN3 towards FNO2, CINO2, NO2SbF6, and NO2BF4 was investigated. At -30°C or below in a solvent-free system sodium azide did not react with CINO2, NO2BF4, or NO2SbF6. Below -30°C silver azide did not react either with neat C1NO2. Treatment of Me3SiN3 with pure C1NO2 led to the formation of C1N3, N2O, and Me3SiOSiMe3. A mechanism for this reaction has been proposed. Pure chlorine azide was isolated by fractional condensation and identified by its low-temperature Raman spectrum (liquid state). The reaction of Cp2Ti(N3)2 with C1NO2 also yielded C1N3 as the only azide-containing reaction product. Treatment of FNO2 with NaN3 at temperatures as low as -78°C always ended in an explosion which was probably due to the formation of FN3 as one of the reaction products. The reaction of NO2SbF6 with NaN3 in liquid CO2 (-55°C· T· -35°C) as the solvent afforded a new azide species which was stable at low temperature in solution only and was investigated by means of low-temperature Raman spectroscopy. The obtained vibrational data give strong evidence for the presence of tetranitrogen dioxide, N4O2, which can be regarded as nitryl azide (NO2N3). The structure and vibrational frequencies of N4O2 were computed ab initio at correlated level (MP2/6-31 + G*). In liquid xenon (-100°C· T· -60°C) NaN3 did not react with NO2SbF6. A previous literature report on the preparation of N4O2 could not be established.

The photodissociation dynamics of chlorine azide (ClN(3)) at the 157 nm region was studied theoretically using the multireference configuration interaction method and the complete active space self-consistent field direct dynamics method. The excitation at the 157 nm region was assigned to the 4 (1)A(')(S(7))--X (1)A(')(S(0)) transition. A likely pathway for the formation of cyclic N(3) after this transition was identified by direct dynamics as follows: ClN(3) excited to 4 (1)A(')(S(7)) dissociates after about 40 fs to excited N(3)(2 (2)A('), with about 44 kcal/mol internal energy) +Cl((2)P). This vibrationally hot N(3)(2 (2)A(')) goes diabatically through a conical intersection with N(3)(1 (2)A(')) at 44 fs onto 1 (2)A('). At 19 fs later and repeatedly after every 55 fs, N(3)(1 (2)A(')) crosses and trickles down via Coriolis coupling to N(3)(2 (2)A(")/ (2)B(1)) state, which has a potential minimum at the cyclic-N(3) structure. Some fraction of N(3)(2 (2)A(")/ (2)B(1)) produced will survive dissociation and will be found as the cyclic N(3), and some other fraction will eventually dissociate to N((2)D)+N(2) over a high barrier found previously.

Photofragment translational spectroscopy was used to identify the primary and secondary reaction pathways in 193 nm photodissociation of chlorine azide (ClN(3)) under collision-free conditions. Both the molecular elimination (NCl+N(2)) and the radical bond rupture channel (Cl+N(3)) were investigated and compared with earlier results at 248 nm. The radical channel strongly dominates, just as at 248 nm. At 193 nm, the ClN(3) (C (1)A(")) state is excited, rather than the B (1)A(') state that is accessed at 248 nm, resulting in different photofragment angular distributions. The chlorine translational energy distribution probing the dynamics of the radical bond rupture channel shows three distinct peaks, with the two fastest peaks occurring at the same translational energies as the two peaks seen at 248 nm that were previously assigned to linear and "high energy" N(3). Hence, nearly all the additional photon energy relative to 248 nm appears as N(3) internal excitation rather than as translational energy, resulting in considerably more spontaneous dissociation of N(3) to N(2)+N.

We report on an H(D)-atom Rydberg tagging experiment for H(D)N(3) photolysis providing detailed dynamical information on the wavelength dependence of the H(D) + N(3) channel. We observe subtle yet striking changes in the photochemical dynamics as the photolysis energy passes through approximately 5.6 eV. In addition to producing linear azide with an average of approximately 40% of available energy appearing as translation, a second H(D)-atom producing channel grows in above this energy releasing only about 15%. An observed (inverse) isotope effect suggests that statistical decomposition on S(0) is unimportant. High level ab initio quantum chemical calculations reveal a transition state to cyclization of the N(3) moiety in H(D)N(3) on the first excited singlet (S(1)) surface that is close in energy to the experimentally observed threshold energy for this "slow channel". Furthermore, the translational energy release of the "slow channel" is energetically consistent with cyclic-N(3) formation. This work provides the clearest presently available insights into how ring closure can occur in azide photochemistry.

Measurements of NCl(a) kinetics are being carried out in support of the effort to develop an NCl(a) driven iodine laser. Photolysis of ClN 3 has been used as a radical source in several previous kinetic studies, as this produces high yields of NCl(a). It had been assumed that NCl(a) was a primary photoproduct. Measurements made under collision-free conditions now indicate that NCl(a) is a minor product, and that Cl and N 3 are produced with a branching fraction of 0.95. In the present study we show that NCl(a) is efficiently produced by secondary photochemical reactions when ClN 3 is photolyzed at moderate pressures. The implications of this finding for kinetic studies that rely on phot olytic NCl(a) generation are considered. The effect of temperature on NCl(a) quenching rate constants is being investigated because the NCl(a)/I laser operates at elevated te mperatures (>400 K). Quenching by H 2 , HCl, Cl 2 , and O 2 in the temperature range from 295-460 K has been examined in the present study. Keywords: All gas-phase iodine laser, nitrogen chloride, chlorine azide photolysis, energy transfer kinetics.

Electron attachment to chlorine azide (ClN(3)) was studied using a flowing-afterglow Langmuir-probe apparatus. Electron attachment rates were measured to be 3.5x10(-8) and 4.5x10(-8) cm(3) s(-1) at 298 and 400 K, respectively, with an estimated 35% absolute accuracy. Cl(-) was the sole ion product of the attachment reaction; weak ion signals were observed for other anions and attributed to impurities and secondary ion-molecule reactions. Assuming a relative uncertainty of +/-10% for these data, an activation energy for the attachment reaction may be given as 24+/-10 meV.

Photofragmentation translational spectroscopy was used to identify the primary and secondary reaction pathways in the KrF laser (248 nm) photodissociation of chlorine azide (ClN(3)) under collision-free conditions. Both the molecular channel producing NCl (X (3)Sigma,a (1)Delta) + N(2) and the radical channel producing Cl ((2)P(J)) + N(3) were analyzed in detail. Consistent with previously reported velocity map ion imaging experiments [N. Hansen and A. M. Wodtke, J. Phys. Chem. A 107, 10608 (2003)] a bimodal translational energy distribution is seen when Cl atoms are monitored at mz = 35(Cl(+)). Momentum-matched N(3) counterfragments can be seen at mz = 42(N(3) (+)). The characteristics of the observed radical-channel data reflect the formation of linear azide radical and another high-energy form of N(3) (HEF-N(3)) that exhibits many of the characteristics one would expect from cyclic N(3). HEF-N(3) can be directly detected by electron-impact ionization more than 100 mus after its formation. Products of the unimolecular dissociation of HEF-N(3) are observed in the mz = 14(N(+)) and mz = 28(N(2) (+)) data. Anisotropy parameters were determined for the primary channels to be beta = -0.3 for the NCl forming channel and beta = 1.7 and beta = 0.4 for the linear N(3) and HEF-N(3) forming channels, respectively. There is additional evidence for secondary photodissociation of N(3) and of NCl.

A numerical integration method was used to solve the mathematical system corresponding to the mechanism of the reaction of Cl atoms with chlorine azide, N 3 Cl. The identification of calculated kinetic curves of the species involved in the mechanism with the experimental curves led to the determination of rate constants of the following secondary reactions: (2) Cl + N 3 → NCl + N 2 (3) N 3 + N 3 → 3N 2 (4) NCl + NCl → N 2 + Cl 2 At 298K, the rate constants were found to be k 2 : 0.75 – 1.5 × 10 −11 , k 3 : 5 – 8 × 10 −11 , and k 4 : 0.5 – 1 × 10 −11 (units are cm 3 molecule −1 sec −1 ).

Experiments directed toward elucidating the nature of fragments produced by the photodissociation of ClN3 have been performed. The utlraviolet absorption spectrum of this molecule exhibits three features between 300 and 170 nm, with λmax = 250, 205, and

UCl6, fur das eine verbesserte Darstellungsvorschrift angegeben wird, last sich mit Chloridionen zum Hexachlorouranat(V) und mit wasserstoffhaltigen Losungsmitteln wie H2CCl2 zu Uranpentachlorid reduzieren. Mit Chlorazid bildet es die Uranchloridazide UCl5N3 und UCl4(N3)2, die sich jedoch nur in schlechter Ausbeute als Gemisch isolieren lassen, weil sie mit dem Losungsmittel weiterreagieren. Ist das Losungsmittel H2CCl2 oder 1,2-Dichlorathan, so entsteht dabei NH4UCl6 als Hauptprodukt; mit CCl4 als Losungsmittel wird das Triazidocarbenium-Salz [C(N3)3]UCl6 in hoher Ausbeute erhalten. Der Reaktionsweg zu diesen Endprodukten verlauft uber Zwischenstufen, die IR-spektroskopisch identifiziert werden konnten. Das Infrarotspektrum von UCl5N3 und UCl4(N3)2 wird mitgeteilt, auserdem werden Angaben zur Kristallstruktur von [C(N3)3]UCl6 gemacht. About the Chemistry of Uranium Hexachloride and Uranium Pentachloride Azide UCl6, for which an improved method of preparation is given, can be reduced with chloride ions to give hexachlorouranate(V) and with solvents containing hydrogen such as H2CCl2 to give uranium pentachloride. With chlorine azide the uranium chloride azides UCl5N3 and UCl4(N3)2 are formed, but they can only be obtained in low yields as a mixture because of their reactivity towards the solvent used. With H2CCl2 or 1.2-dichloroethane as solvent, NH4UCl6 is the main product; with CCl4 as solvent, the triazidocarbenium salt [C(N3)3]UCl6 is formed with high yield. Intermediates of the reaction path to these products could be identified by I. R. spectroscopy. The infrared spectra of UCl5N3 and UCl4(N3)2 are reported and data about the crystal structure of [C(N3)3]UCl6 are given.

The photolysis of ClN 3 at 272 and 300 nm results in prompt emission between 600 and 900 nm from two different species which most probably are different states (either electronic or vibrational) of ClN. One state, at present still unidentified, has a radiative lifetime of 26 ± 5 μs and is quenched by Cl 2 with a rate constant of (7.5 ± 2) × 10 −12 cm 3 molecule −1 S −1 . The other state, tentatively identified as the b 1 Σ + state, has a radiative lifetime of 0.25 ± 0.05 ms and is quenched by Cl 2 with a rate constant of (1.5 ± 0.5) × 10 −13 cm 3 molecule −1 s −1 .

The reaction kinetics of chlorine atoms with chlorine azide, N3Cl, was studied at pressures near 1 torr in a discharge flow reactor coupled to a quadrupole mass spectrometer adapted to the analysis of free radicals. The rate constant of the initial step: Cl+N3ClN3+Cl2 (1) was found to be k1=2.3×10−11 exp (−1100/RT) cm3 molecule−1 sec−1 between 300 and 657 K. N3, NCl and NCl2 free radicals, produced from the Cl+N3Cl reaction, were detected by mass spectrometry. The mass spectrometric study of these radicals and the determination of stoichiometry showed evidence for the secondary reactions of N3, NCl and N3Cl. The rate constant of the reaction: NCl+Cl2NCl2+Cl (5) was determined as k5=(1.0±0.2)×10−12 cm3 molecule−1 sec−1 at room temperature. The thermal decomposition of N3Cl was studied between 600 and 850 K in the same flow reactor heated isothermically. The NCl radical was mass spectrometrically detected as an intermediate of the decomposition. Kinetic data were obtained showing at least partly heterogeneous character of the decomposition. All these results made it possible to discuss some aspects of the mechanism of the explosive decomposition of N3Cl and more especially of the initial stage of this decomposition.

The 15N NMR spectra of HN3 and CIN3 solutions were recorded under triply labelled conditions. The chemical shifts and coupling constants are discussed with respect to the structure and in relation to other isoelectronic compounds.

SbCl5 und Chlorazid reagieren in der Gasphase unter Bildung des in Benzol dimer loslichen, explosiven Antimontetrachloridazids, [SbCl4N3]2. Nach dem IR-Spektrum (33 bis 4000 cm−1) sowie Teilen des RAMAN-Spektrums enthalt die Molekel einen ebenen Sb–N-Vierring (Symmetrie D2h). Mit Pyridin wird der Ring gespalten, wobei das in Benzol monomer losliche Addukt SbCl4N3 · Py entsteht, dessen IR-Spektrum mit dem des SbCl5. Py verglichen wird. Die N-Atome von N3 und Pyridin besetzen die trans-Positionen des oktaedrisch umgebenen Antimons. SbCl5 vapour and chlorine azide react under formation of the explosive antimony tetrachloride azide [SbCl4N3]2. According to the IR spectrum (33-4000 cm−1) and parts of the RAMAN spectrum the molecules possess planar, fourmembered Sb-N rings (symmetry D2h) · With pyridine, ring fission to monomeric SbCl4N3. pyridine occurs, whose IR spectrum is compared with that of SbCl5. pyridine, showing that the azide and pyridine groups occupy trans-positions around the octahedrally surrounded Sb.

Bei der Reaktion von Diathylaluminiumchlorid mit Chlorazid bei 25–30 °C entsteht trimeres Athylaluminiumchloridazid, [C2H5AlClN3]3. Die Verbindung stellt eine olige, farblose, sehr hygroskopische und im Vakuum destillierbare Flussigkeit dar, die sich langsam unter Bildung von Athylaluminiumdichlorid und Athylaluminiumdiazid zersetzt. Nach dem Schwingungsspektrum (IR und RAMAN) liegt ein uber die α-N-Atome der Azidogruppen verknupfter AlN-Sechsring vor (Symmetrie C3v). The reaction of diethylaluminiumchloride with chlorine azide at 25–30 °C leads to the trimeric ethylaluminiumchloridazide [C2H5AlClN3]3. This compound is an oily, colourless, and very hygroscopic liquid which can be distilled in vacuo, but slowly decomposes by formation of ethylaluminiumdichloride and ethylaluminiumdiazide. The vibrational spectrum (IR und RAMAN) indicates a structure consisting of a six-membered AlN-ring (symmetry C3v).

The dialkylmetal azides [(CH3)2AlN3]3, [(C2H5)2GaN3]3, [(C2H5)2,InN3]2 and [(C2H5)2TI]+N−3 were prepared from the corresponding metal trialkyls and chlorine azide. Their properties are given and their structures were determined from their vibrational spectra (IR and Raman). The trimeric azides of Al and Ga form planar six-membered metal-nitrogen rings (symmetry D3h), the dimeric azide of indium probably forms a planar four-membered In2N2-ring and the structure of diethylthallium azide is ionic.

The microwave spectra of four isotopic species of chlorine azide, ClN3, have been observed in the frequency range 26–48 GHz. From the measured values of the rotational constants, the molecule has been deduced to be planar with the following internuclear parameters: r(Cl–N(1)) = 1.745 ± 0.005 A, r(N(1)–N(2)) = 1.252 ± 0.010 A, r(N(2)–N(3)) = 1.133 ± 0.010 A, ∠ClN(1)N(2) = 108°40′ ± 30′, ∠N(1)N(2)N(3) = 171°56′ ± 30′, with Cl and N(3) trans. Values for the chlorine quadrupole coupling constants were obtained for all isotopic species, and for the most abundant, 35Cl14N3, were transformed into the principal field gradient axis system. The values obtained are consistent with the deduced structure.

By reaction of gaseous chlorine azide with SnCl4, TiCl4 and VOCl3 at 0°C the crystalline, hygroscopic, explosive Azidechlorides SnCl3N3, TiCl3N3 and VOCl3N3 respectively can be obtained in good yields. Infra-red spectra show these compounds to be island-structures with great degree of nonpolar MN3-bondings (M = Sn, Ti symmetry C3v; M = V symmetry Cs). By interaction of solvents TiCl3N3 and VOCl2N3 split off N2 and Cl2 and the well-defined nitride-compounds TiNCl and VON are obtainable.

The He(I) PE spectrum of the title compound 1 has been obtained. Based on quantum mechanical calculations, the ionization potentials have been assigned to molecular orbitals. Good correlation was obtained with the corresponding ionization potentials of chlorine azide (2), bromine azide (3), hydrazoic acid (4), and methyl azide (5). The low stability of 1 is apparent from its electronic structure.

Publisher Summary This chapter discusses the chemistry of the halogen azides. Fluorine azide is best prepared from dry hydrazoic acid and fluorine in the gas phase. Decomposition reactions of the fluorine azide are avoided when the reactants are diluted with N 2 . Because in this reaction chlorine azide is produced in high concentrations locally, explosions can occur. For preparative purposes, the most convenient method is the reaction of chlorine gas, diluted with nitrogen, with an aqueous solution of sodium azide. Solutions of bromine azide in hexane, carbon tetrachloride, and other inert solvents are obtained from silver azide and bromine when the suspension contains some dry sodium sulfate, to avoid decomposition of the BrN 3 by traces of water. For preparative purposes, solutions of bromine azide in dichloromethane or pentane can be prepared by addition of bromine to an agitated two-phase system held at 0°C, the aqueous phase of which consists of sodium azide and 30% HC1.

Publisher Summary This chapter discusses the chemistry of the halogen azides. Fluorine azide is best prepared from dry hydrazoic acid and fluorine in the gas phase. Decomposition reactions of the fluorine azide are avoided when the reactants are diluted with N 2 . Because in this reaction chlorine azide is produced in high concentrations locally, explosions can occur. For preparative purposes, the most convenient method is the reaction of chlorine gas, diluted with nitrogen, with an aqueous solution of sodium azide. Solutions of bromine azide in hexane, carbon tetrachloride, and other inert solvents are obtained from silver azide and bromine when the suspension contains some dry sodium sulfate, to avoid decomposition of the BrN 3 by traces of water. For preparative purposes, solutions of bromine azide in dichloromethane or pentane can be prepared by addition of bromine to an agitated two-phase system held at 0°C, the aqueous phase of which consists of sodium azide and 30% HC1.

The He(I) PE spectrum of the title compound 1 has been obtained. Based on quantum mechanical calculations, the ionization potentials have been assigned to molecular orbitals. Good correlation was obtained with the corresponding ionization potentials of chlorine azide (2), bromine azide (3), hydrazoic acid (4), and methyl azide (5). The low stability of 1 is apparent from its electronic structure.

The electronic structure of the ground states of chlorine isocyanate and chlorine azide is investigated using ab initio LCAO–MO–SCF calculations with a moderately large basis. The difference in strength of the Cl—N bond for the two compounds is found to be caused by a greater contribution from the N s orbital of the azide. The calculations also show that the total charge on chlorine in these compounds is positive.