High-pressure study on calcium azide(Ca(N_(3))_(2)):Bending of azide ions stabilizes the structure

The high-pressure structure and elastic properties of calcium azide(Ca(N_(3))_(2))were investigated using in-situ highpressure x-ray diffraction and Raman scattering up to 54 GPa and 19 GPa,respectively.The compressibility of Ca(N_(3))_(2)changed as the pressure increased,and no phase transition occurred within the pressure from ambient pressure up to 54 GPa.The measured zero-pressure bulk modulus of Ca(N_(3))_(2)is higher than that of other alkali metal azides,due to differences in the ionic character of their metal-azide bonds.Using CASTEP,all vibration modes of Ca(N_(3))_(2)were accurately identified in the vibrational spectrum at ambient pressure.In the high-pressure vibration study,several external modes(ext.)and internal bending modes(ν_(2))of azide anions(N_(3)^(-))softened up to~7 GPa and then hardened beyond that pressure.This evidence is consistent with the variation observed in the F_(E)–f_(E)data analyzed from the XRD result,where the slope of the curve changes at 7.1 GPa.The main behaviors under pressure are the alternating compression,rotation,and bending of N_(3)^(-)ions.The bending behavior makes the structure of Ca(N_(3))_(2)more stable under pressure.

Simplified quantitative analysis method and its application in the insitu synthesized copper-based azide chips

Copper-based azide(Cu(N_(3))2 or CuN_(3),CA)chips synthesized by in-situ azide reaction and utilized in miniaturized explosive systems has become a hot research topic in recent years.However,the advantages of in-situ synthesis method,including small size and low dosage,bring about difficulties in quantitative analysis and differences in ignition capabilities of CA chips.The aim of present work is to develop a simplified quantitative analysis method for accurate and safe analysis of components in CA chips to evaluate and investigate the corresponding ignition ability.In this work,Cu(N_(3))2 and CuN_(3)components in CA chips were separated through dissolution and distillation by utilizing the difference in solubility and corresponding content was obtained by measuring N_(3)-concentration through spectrophotometry.The spectrophotometry method was optimized by studying influencing factors and the recovery rate of different separation methods was studied,ensuring the accuracy and reproducibility of test results.The optimized method is linear in range from 1.0-25.0 mg/L,with a correlation coefficient R^(2)=0.9998,which meets the requirements of CA chips with a milligram-level content test.Compared with the existing ICP method,component analysis results of CA chips obtained by spectrophotometry are closer to real component content in samples and have satisfactory accuracy.Moreover,as its application in miniaturized explosive systems,the ignition ability of CA chips with different component contents for direct ink writing CL-20 and the corresponding mechanism was studied.This study provided a basis and idea for the design and performance evaluation of CA chips in miniaturized explosive systems.

Synthesis and characterization of a 1,3-dibutylimidazolium azide([BBIm][N_(3)]) : A promising green energetic ionic liquid

In the pursuit of advancing imidazolium-based energetic ionic liquids (EILs),the current study is devoted to the synthesis and characterization of 1,3-dibutyl-imidazolium azide ([BBIm][N_(3)]),as a novel member in this ionic liquids class.The chemical structure of this EIL was rigorously characterized and confirmed using FTIR spectroscopy,1D,and 2D-NMR analyses.The thermal behavior assessment was conducted through DSC and TGA experiments.DSC analysis revealed an endothermic glass transition at T_(g)=-61℃,followed by an exothermic degradation event at T_(onset)=311℃.Similarly,TGA thermograms exhibited a one-stage decomposition process resulting in 100% mass loss of the sample.Furthermore,the short-term thermal stability of the azide EIL was investigated by combining the non-isothermal TGA data with the TAS,it-KAS,and VYA/CE isoconversional kinetic approaches.Consequently,the Arrhenius parameters(E_(a)=154 kJ·mol^(-1),Log(A/s^(-1))=11.8) and the most probable reaction model g(a) were determined.The observed high decomposition temperatures and the significantly elevated activation energy affirm the enhanced thermal stability of the modified EIL.These findings revealed that[BBIm][N_(3)]EIL can be a promising candidate for advanced energetic material application.

Template synthesis of copper azide primary explosive through Cu2O@HKUST-1 core-shell composite prepared by “bottle around ship” method

Copper azide(CA), as a primary explosive with high energy density, has not been practically used so far because of its high electrostatic sensitivity. The Cu2O@HKUST-1 core-shell structure hybrid material was synthesized by the “bottle around ship” methodology in this research by regulating the dissolution rate of Cu2O and the generation rate of metal-organic framework(MOF) materials. Cu2O@HKUST-1 was carbonized to form a Cu O@porous carbon(CuO@PC) composite material. CuO@PC was synthesized into a copper azide(CA) @PC composite energetic material through a gas-solid phase in-situ azidation reaction.CA is encapsulated in PC framework, which acts as a nanoscale Faraday cage, and its excellent electrical conductivity prevents electrostatic charges from accumulating on the energetic material’s surface. The CA@PC composite energetic material has a CA content of 89.6%, and its electrostatic safety is nearly 30times that of pure CA(1.47 mJ compared to 0.05 mJ). CA@PC delivers an outstanding balance of safety and energy density compared to similar materials.

Fabrication of electrostatic safety copper azide film with in situ growing MOF

Due to its extremely low electrostatic sensitivity,copper azide primary explosive is greatly limited in practical applications.In this study,a composite film with Cu-MOF in-situ growth on carbon nanofilm was prepared by electrospinning and solvothermal methods,and CNF@Cu-N3film with electrostatic safety was obtained by carbonization and azide later.Its electrostatic sensitivity(E50)was greatly increased from 0.05 mJ of raw materials to 4.06 mJ,and still maintained a good detonation performance which could successfully detonate the CL-20 secondary explosive.This is mainly due to the synergistic effect of the carbon film and the MOF structure,which greatly improves the conductivity of the entire system and the uniform distribution of copper particles,providing a new preparation strategy for metal azide film that is suitable for the micro-initiator device.

Research Progress of Nano Copper Azide

The development trend of miniaturization, chipization, integration, and intelligence of new energetic devices has put forward higher requirements for primary explosives, and the toxicity of lead-containing initiating explosives has also caused increasing concerns. Nano copper azide, due to its green and high-energy characteristics, has attracted increasing interest from researchers in recent years. The research progress of Nano copper azide energetic materials is summarized from the design and preparation of composite energetic materials, and the analysis of sensitivity changes. On this basis, the key points to realize its application prospects are discussed: Develop the preparation method of carbon material modification and the combination of processing and forming to prepare new composite materials to make up for their overly sensitive defects, while giving full play to their advantages of high energy density. By comparing the existing research progress of Nano copper azide, we can understand its performance parameters more systematically, and guide the further application of Nano copper azide. .

Synthesis of Two Furazano Azides

bis(azidomethyl) 3,3′ bis(1,2,4 oxadiazole)(Ⅰ) and bis(azidoacetamino) oxazofurazan(Ⅱ) were synthesized. The structures of these two compounds have been identified by IR, 1H NMR, MS and elemental analysis. Azido groups were introduced into furazan derivatives and energetic materials of high nitrogen content and high enthalpy of formation can be obtained. The densities of compound Ⅰ and Ⅱ are relatively high. Compound Ⅰ is an azide of lower melting point, it is hopeful to be applied as energetic plastic additives.

Structural Dynamics of Phenyl Azide in Light-Absorbing Excited States： Resonance Raman and Quantum Mechanical Calculation Study

The excited state structural dynamics of phenyl absorbing S2（A＇）, S3（A＇）, and S6（A＇） states were troseopy and complete active space self-consistent and the UV absorption bands were assigned on azide （PhN3） after excitation to the light studied using the resonance Raman specfield calculations. The vibrational spectra the basis of the Fourier transform （FT）- Raman, FT-infrared measurements, the density-functional theory computations and the normal mode analysis. The A-, B-, and C-bands resonance Raman spectra in cyclohex- ane, acetonitrile, and methanol solvents were, respectively, obtained at 273.9, 252.7, 245.9, 228.7, 223.1, and 208.8 nm excitation wavelengths to probe the corresponding structural dynamics of PhN3. The results indicated that the structural dynamics in the S2 （A＇）, S3（A＇）, and S6（A＇） states were significantly different. The crossing points of the potential energy surfaces, S2S1（1） and S2S1（2）, were predicted to play a key role in the low-lying excited state decay dynamics, in accordance with Kasha＇s rule, and NT=N8 dissociation. Two decay channels initiated from the Franck-Condon region of the S2（A＇） state were predicted： the radiative S2,min→S0 radiative decay and the S2→S1 internal conversion through the crossing points S2S1 （1）/S2S1（2）.

Substitution Reactions by Azide and Thiocyanide Anions in Room Temperature Ionic Liquids

Conducted in the ionic liquids, activated and inactivated halides, acyl chlorides, tosylate, and bezotriazolyl acylates were converted to corresponding azide and thiocyanide compounds in high yields under mild conditions.

Highly active binuclear Cu(Ⅱ) catalyst bearing an unsymmetrical bipyridine-pyrazole-amine ligand for the azide-alkyne cycloaddition reaction

Ligands containing NH groups often show special characteristics.In this paper,a well-defined dinuclear Cu（II） complex bearing an unsymmetrical bipyridine-pyrazole-amine ligand was synthesized by the condensation of N–H to release H2O.Using sodium L-ascorbate as a reductant,the binuclear complex showed excellent activity in 1,3-dipolar cycloaddition reactions between alkynes and azides to obtain 1,4-disubstituted triazoles in 95%–99% isolated yields.

Synthesis and Crystal Structure of an Azide Bridged Binuclear Zinc(Ⅱ) Dimer Containing Taurine Schiff Base [Zn_2(C_8H_9N_2O_3S)_2·(N_3)_2·(H_2O)_2]_2·_2H_2O

The title complex [Zn2L2（N3）2（H2O）2]·2H2O （L = N-（2-pyridylmethylidene） taurine） has been synthesized in a methanol-water solution. The crystal belongs to monoclinic, space group P2 1/C with a = 15.8064（10）, b = 10.5015（5）, c = 17.3193（11） ,A, β= 111.314（2）°, V = 2678.2 （3） ,A ^3 C16H26N10O10S2Zn2, Mr = 713.33, Z = 4, DC = 1.769 g/cm^3, μ = 2.017 mm^-1 and F（000） = 1456. The asymmetric unit consists of two half-molecules of the complex and two water molecules. Four N and two O atoms form the coordination environment of each Zn atom, resulting in a distorted octahedral configuration. The two halves of each independent dimer are related by a crystallographic inversion centre, which lies at the centre of the ring formed by two Zn atoms and the coordinating atoms of the two azide anions. The average separation of Zn（Ⅱ）...Zn（Ⅱ） is 3.322 A. The molecules are linked by O-H...O hydrogen bonds, generating an interesting zigzag infinite chain structure in the ac plane.

THE REACTION OF BENZOYL SUBSTITUTED HETEROCYCLIC KETENE AMINALS WITH ARYL AZIDES.A FACILE APPROACH TO SYNTHSIZE 1,5-DIARYL-4-(2-IMIDAZOLINYL)-1,2,3-TRIAZOLES

Heterocyclic ketene aminals 1 react with aryl azides 2 to give the titled compounds 3,and in some cases also with the formation of fused heterocycles 4.

Dense copper azide synthesized by in-situ reaction of assembled nanoporous copper microspheres and its initiation performance

Copper azide with high density was successfully synthesized by in-situ reaction of nanoporous copper(NPC)precursor with HN_(3) gaseous.NPC with pore size of about 529 nm has been prepared by electroless plating using polystyrene(PS)as templates.The copper shells thickness of NPC was controlled by adjusting the PS loading amount.The effects of copper shell on the morphology,structure and density of copper azide were investigated.The conversion increased from 87.12%to 95.31%when copper shell thickness decrease from 100 to 50 nm.Meanwhile,the density of copper azide prepared by 529 nm NPC for 24 h was up to 2.38 g/cm^(3).The hollow structure of this NPC was filled by swelling of copper azide which guaranteed enough filling volume for keeping the same shape as well as improving the charge density.Moreover,HNS-IV explosive was successfully initiated by copper azide with minimum charge thickness of 0.55 mm,showing that copper azide prepared has excellent initiation performance,which has more advantages in the application of miniaturized explosive systems.

Synthesis, Crystal Structure and Characterization of Energetic Monovalent Copper Azide Complex: [Cu_2(dmpz)(N_3)_2]_n

A novel cuprous azide complex with the formula of [Cu2（dmpz）（N3）2]n（1, dmpz： 2,6-dimethylpyrazine） has been synthesized through hydrothermal synthesis with the reducibility of H3PO3 and structurally characterized by single-crystal X-ray diffraction method. Single-crystal X-ray diffraction analysis reveals the title complex represents a three-dimensional network structure featuring 2D [Cu N3]n plane units bridged by bridging dmpz ligands to form a 3D network. Research results reveal that 1 has lower impact sensitivity and friction sensitivity, which may be expected to become insensitive energetic material and have potential applications. Crystal data： monoclinic, space group C2/c, a = 17.8599（15）, b = 8.2889（5）, c = 14.8076（14） A, β = 113.2580（10）o, V = 2014.0（3） A3, Z = 8, S = 1.025, the final R = 0.0303, w R = 0.0825 for 1460 observed reflections with I 2σ（I） and R = 0.0386, wR = 0.0870 for all reflections. In addition, elemental analysis, IR, and sensitivity characterization are presented.

Reduction of Azides to Amines with New Metal /Lewis Acid Systems in H_2O or Aqueous EtOH

The azides were reduced to the corresponding amines by two new metal/Lewis acid systems in water or in aqueous EtOH in yields ranging from 80%-95%. The reaction rates were faster in water than in aqueous EtOH in most cases. All 16 azides with different functional groups were well reduced to the corresponding amines in excellent yields and reaction rates.

Synthesis and Structural Characterization of Bis(2,2'-bpy)bis(azide)cobalt(Ⅲ)nitrate dihydrate

The title complex [CoIII(2, 2?bpy)2(N3)2]種O3?H2O was obtained by an auto-oxidization reaction of cobalt nitrate with 2, 2-bpy and sodium azide in aqueous solution at room temperature, and violet single crystals were prepared in ethanol solution. The structure was determined by X-ray crystallography. The crystal is of triclinic, space group P ?with a = 8.285(4), b = 11.990(8), c = 12.596(7) ? a = 86.630(3), b = 86.280(5), g = 71.130(10)? C20H20CoN11O5, Mr = 553.40, Z = 2, V = 1180.6(12) ?, F(000) = 568, Dc = 1.557 g/cm3, m = 0.784 mm-1, R = 0.0403 and wR = 0.1008. The title complex consists of a [CoⅢ(2, 2?bpy)2(N3)2]+ cation, a NO3- anion and two lattice water molecules. The center CoⅢ ion coordinated by two chelating 2, 2?bpy ligands and two terminal azide groups with a CoN6 coordination environment exhibits a distorted octahedral geometry.

Synthesis and Crystal Structure of a Three-dimensional Mn(Ⅱ) Coordination Polymer with 3-(Pyrazin-2-yloxy)-pyridine and Azide Anion as Mixed Bridge Ligand

A three-dimensional coordination polymer [Mn2（μ1.3-N3）4（μ-PP）2]n （PP = 3-（pyrazin-2-yloxy）-pyridine） has been synthesized with 3-（pyrazin-2-yloxy）-pyridine and azide anion as mixed bridge ligand, and its crystal structure was determined by X-ray crystallography. The crystal data： triclinic system, space group P1, with a = 6.794（4）, b = 9.885（6）, c = 9.947（6） A, α = 64.170（6）, β= 84.190（8）, γ= 85.319（8）°, V = 597.7（6）A^3, Z = 1, C18H14Mn2N18O2, Mr = 624.35, Dc = 1.735 g/cm^3, F（000） = 314 and μ = 1.117 mm^-1. In the crystal, the azide anion acts as a bridge ligand and makes adjacent Mn（Ⅱ） ions connect into a two-dimensional sheet on the ab plane, then 3-（pyrazin-2-yloxy）-pyridine serves as a bidentate bridge ligand to connect neighboring sheets along

Sonochemical Behavior of Aqueous Solutions of Iodide, Bromide and Azide

The sonolysis of azide solutions was investigated. The main product isnitrogen, which is formed in the reaction of N_3^- with OH radicals in the millimolar concentrationrange. At higher azide concentration, additional nitrogen is formed as hydrogen atoms are scavenged.Ammonia and hydrazine are minor products of the N_3^- sonolysis. Solutions of iodide and bromideare also irradiated under pH conditions where reactions of the products, i.e., hydrogen per oxideand iodide (or bromide) do not occur. The total yield of the products as well as the hydrogen yieldis independent of the solute concentration. The results are understood in terms of the competitionof the OH + OH and the OH + solute reactions. A local concentration of 4 X 10^(-3) mol/L of the OHradicals in an interfacial region between the cavitation bubbles and the liquid is derived from thedata obtained.

A New Approach to 2,3-Dihydro-1H-1,5-Benzodiazepines from the Reaction of o-Nitrophenylazide with α,β-Unsaturated Ketones Promoted by Samarium Diiodide

o-Nitrophenylazide was reduced by SmI2 in anhydrous THF at room temperature to produce active intermediate 2 (samarium amide), "living" double-anion in situ which reacted smoothly with α，β-unsaturated ketones to afford 2,3-dihydro-1H-1,5-benzodiazepines in good yields under mild and neutral conditions.

Density Functional Study on the Vibrational Frequencies of Hydrazoic Acid and Methyl Azide

Harmonic vibrational frequencies of hydrazoic acid and methyl azide are calculated using HF. MP2 methods and five popular density functional (DFT) methods and compared with experimental results. Of these seven methods, BLYP reproduces the observed frequencies most satisfactorily, while the results in HF and MP2 are worse. These indicate the BLYP calculation is a very promising approach for understanding the observed spectral features.