Assessment of electrostatic discharge sensitivity of nitrogen-rich heterocyclic energetic compounds and their salts as high energy-density dangerous compounds:A study of structural variables

Nitrogen-rich heterocyclic energetic compounds(NRHECs)and their salts have witnessed widespread synthesis in recent years.The substantial energy-density content within these compounds can lead to potentially dangerous explosive reactions when subjected to external stimuli such as electrical discharge.Therefore,developing a reliable model for predicting their electrostatic discharge sensitivity(ESD)becomes imperative.This study proposes a novel and straightforward model based on the presence of specific groups(-NH_(2) or-NH-,-N=N^(+)-O^(-)and-NNO_(2),-ONO_(2) or-NO_(2))under certain conditions to assess the ESD of NRHECs and their salts,employing interpretable structural parameters.Utilizing a comprehensive dataset comprising 54 ESD measurements of NRHECs and their salts,divided into 49/5 training/test sets,the model achieves promising results.The Root Mean Square Error(RMSE),Mean Absolute Error(MAE),and Maximum Error for the training set are reported as 0.16 J,0.12 J,and 0.5 J,respectively.Notably,the ratios RMSE(training)/RMSE(test),MAE(training)/MAE(test),and Max Error(training)/Max Error(test)are all greater than 1.0,indicating the robust predictive capabilities of the model.The presented model demonstrates its efficacy in providing a reliable assessment of ESD for the targeted NRHECs and their salts,without the need for intricate computer codes or expert involvement.

Two Novel Nitrogen-rich Energetic Coordination Compounds M_2(DAT)_5(H_2O)_3(TNR)_2(M = Zn and Co):Synthesis,Characterization,Thermal Properties and Sensitivity

Two novel energetic coordination compounds Zn2（DAT）5（H2O）3（TNR）2 and Co2（DAT）5（H2O）3（TNR）2 were synthesized and their structures were characterized by elemental analysis and FT-IR spectroscopy.The crystal structures were determined by single-crystal X-ray diffraction.The results reveal that the compounds have similar molecular structures and the crystals belong to the triclinic system,space group P with a = 11.491（3）,b = 13.564（3）,c = 15.496（3） ,V = 2180.4（8） 3,C17H28 Zn2N36O19,Mr = 1203.02 g·mol-1,Dc = 1.832 g·cm-3,μ（MoKα） = 1.221 mm-1,F（000） = 1223,Z = 2,R = 0.0596 and wR = 0.1514 for 11289 observed reflections（I 〉 2σ（I）） for Zn2（DAT）5（H2O）3（TNR）2 and a = 11.5291（13）,b = 13.4894（15）,c = 15.4852（17） ,V = 2164.8（4） 3,C17H28Co2N36O19,Mr = 1190.14 g·mol-1,Dc = 1.826 g·cm-3,μ（MoKα） = 0.888 mm-1,F（000） = 1211,Z = 2,R = 0.0576 and wR = 0.1431 for 11218 observed reflections（I 〉 2σ（I）） for Co2（DAT）5（H2O）3（TNR）2,respectively.The thermal decomposition characteristics of the com-pounds were investigated using differential scanning calorimetry and thermal gravimetry-diffediffer-rential thermal gravimetry.The results of thermal decomposition processes were similar for the two compounds.Both undergo four-step decomposition after the loss of coordinated H2O molecules.The final solid residues for the two DAT complexes were the corresponding metal oxides.The kinetic parameter of the first exothermic process of the compounds was studied by applying the Kissinger and Ozawa-Doyle methods.The thermodynamic parameters of the activation could be calculated.Sensitivity tests revealed that Co2（DAT）5（H2O）3（TNR）2 was more sensitive than Zn2（DAT）5（H2O）3（TNR）2.

Theoretical design of new bridge-ring insensitive high energy compounds by selected normal Diels-Alder reactions between NH_(2)-substituted oxazoles and NO_(2)/NF_(2)/NHNO_(2)-substituted ethylenes/acetylenes

In this work,NH_(2)-substituted oxazoles and NO_(2)/NF_(2)/NHNO_(2)-substituted ethylenes/acetylenes were designed and used as dienes and dienophiles,respectively,in order to develop new bridge-ring insensitive high energy compounds through the Diels-Alder reaction between them.The reaction type,reaction feasibility and performance of reaction products were investigated in detail theoretically.The results showed that dienes most possibly react with dienophiles through the HOMO-diene controlled normal Diels-Alder reaction at relatively low energy barrier.Tetranitroethylene could react with the designed dienes much more easily than other dienophiles,and was employed to further design 29 new bridge-ring energetic compounds.Due to high heat of formation,density and oxygen balance,all designed bridge-ring energetic compounds have outstanding detonation performance,16 of them have higher energy than HMX(1,3,5,7-tetranitro-1,3,5,7-tetrazocine)and 2 others even possess comparative energy with the representative of high energy compounds CL-20(2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane).The predicted average h50 value of these bridge-ring energetic compounds is 83 cm,showing their low impact sensitivity.The NH2 groups could obviously impel the proceeding of Diels-Alder reactions,but would slightly decrease the energy and sensitivity performance.In all,the new designed bridge-ring compounds have both high energy and low sensitivity,and may be produced through Diels-Alder reactions at relatively low energy barrier.This paper may be helpful for the theoretical design and experiment synthesis of new advanced insensitive high energy compounds.

Synthesis and Crystal Structure of 3,4-Bis(azidoacetamino)furazan

Bis(azidoacetamino)furazan (DAZAF) was synthesized and characterized by elemental analysis, IR, 1H NMR and MS as an energetic compound. The crystal structure of the title compound was determined by single-crystal X-ray diffraction with the following data: C6H6N10O3, monoclinic, P21/n, Z = 4, a = 8.402(3), b = 15.146(3), c = 9.247(3) ? ?= 111.09(2)? V = 1098.0(6) 3, Mr = 266.18, Dc = 1.610 g/cm3, F(000) = 544, ?=1.34 cm-1, R = 0.037 and wR = 0.044 for 2136 observed reflections (I > 2(I)). Intra- and inter-molecular hydrogen bonds were identified between the O and H atoms of two intramolecular acetylamino groups and two intermolecular acetylamino groups, respectively.

Synthesis and Structure of a Mn(Ⅱ)-triazolyl Coordination Polymer Consisting of Dinuclear Units

The reaction of bis（1,2,4-triazolyl-4-yl） （btr） and MnClO4-6H20 gave rise to a Mn（II） complex comprised of unprecedented dinuclear Mn（II） units, {[Mn2（btr）s（H20）5]- （ClO4）4（H20）2]n （1）. Single-crystal X-ray diffraction analysis revealed that 1 crystallizes in the monoclinic space group C2/c. btr adopts two types of bridging modes. One serves as μ-N1 ：N2 bridge through one triazolyl ring of btr forming a dinuclear Mn（II） unit, and the other adopts an exo-bidentate mode using two nitrogen atoms from each triazolyl ring and links the dinuclear units into a 2D cationic layer. ClO4 acts as a counter anion and does not take part in coordination. Interestingly, 2D layers are packed in an ABCABC mode. ClO4- and uncoordinated water molecules locate between the adjacent layers, and extensive hydrogen bonds further stabilize the whole framework.

Density Functional Calculations of C–NO_2 Bond Dissociation Energies for Nitroalkanes Molecules

Bond dissociation energies for the removal of nitrogen dioxide group in some nitroalkane energetic materials have been calculated by using the three hybrid density functional theory （DFT） methods B3LYP, B3PW91 and B3P86 with 6-31g^＊＊ and 6-311g^＊＊ basis sets. The computed BDEs have been compared with the available experimental results. It is found that the B3P86 method with 6-31g^＊＊ and 6-311g^＊＊ basis sets can obtain satisfactory bond dissociation energies （BDEs）, which are in extraordinary agreement with the experimental data. Considering the smaller mean absolute deviation and maximum difference, the reliable B3P86/6-311g^＊＊ method was recommended to compute the BDEs for the removal of nitrogen dioxide group in the nitroalkane energetic materials. Using the method, the BDEs of 8 other nitroalkane energetic materials have been calculated and the maximum difference from experimental value is 1.76 kcal.mo1^-1 （for the BDE of tC4Hg-NOz）, which further proves the reliability of B3P86/6-311g^＊＊ method. In addition, it is noted that the BDEs of C-NO2 bond change slightly for main chain nitroalkane compounds with the maximum difference of only 3.43 kcal mo1^-1.

新型高氮含能化合物Zn(5-NATZ)_2(H_2O)_4的晶体结构(英文)

Tetrazole-based nitrogen-rich compounds are energetic materials due to their high enthalpy of formation,high density and easy to achieve balance of oxygen.5-nitraminotetrazolate(5-NATZ) has been proved to possess excellent energetic properties among the simple tetrazole compounds and its metal complexes were thought to be promising energetic materials.In this paper,a novel nitrogen-rich energetic compound of Zn(5-NATZ)2(H2O)4 was synthesized and determined by X-ray single crystal diffraction technology.

Nitration of 2,2'-Dinitro-4,4'-biphenyldicarboxylic Acid at High Concentration of Sulfuric and Nitric Acids

Nitration of 4,4＇-biphenyldicarboxylic acid（BPDC） was studied and an aromatic carboxylic acid containing four nitro groups was synthesized and characterized through elemental analysis and IR spectra.Crystal structure of TNBPDC（TNBPDC = 2,2＇,6,6＇-tetranitro-4,4＇-biphenyl dicarboxylic acid） was determined by X-ray single-crystal diffraction.The title compound（C20H20N6O14,Mr = 600.42） crystallizes in tetragonal,space group I41/a with a = 9.8774（1）,b = 9.8774（1）,c = 25.335（7） ,V = 2471.7（8） 3,Z = 4,Dc = 1.613 g/cm3,F（000） = 1240,μ（MoKα） = 0.142 mm-1,T = 294（2） K,the final R = 0.0797 and wR = 0.2177 for 554 observed reflections with I〉 2σ（I）.In this crystal,there exist a number of H-bonds which link the molecules to form a three-dimensional infinite network structure.The thermal decomposition of the title compound has been carried out through DSC and TG-DTG analyses at a heating rate of 10 ℃/min.The results indicate that the compound has high heat-resistant stability.

Three New Compounds Based on 4,4＇-Azo-l,2,4-triazol-5-one： Synthesis, Crystal Structure and Thermal Properties

A series of guanidine salts of 4,4＇-azo-l,2,4-triazol-5-one with guanidine（1）, aminoguanidine（2）, diaminoguanidine（3） and triaminoguanidine（4） was prepared. Compounds 2--4 were characterized by infrared（IR） spectroscopy, elemental analysis and single-crystal X-ray diffraction. Thermal decomposition processes of compounds 1--4 were investigated by differential scanning calorimetry（DSC）, and all the compounds showed good thermal stability up to 190 ℃. Moreover, these four guanidine salts are more unstable with the increasing number of amino groups. Thermal stability parameters（Te,0 and Tb）and thermodynamic functions（△S≠, △H≠ and △G≠） for compounds 1-4 were calculated. The constant-volume combustion heats（AcU） for compounds 2--4 were determined and tended to increase with the increase of the number of amino groups. The calculated standard molar enthalpies of forma- tion（△ρH0m） of compounds 2-4 are -541.04, -178.67 and-83.08 kJ/mol, respectively. The impact sensitivities results indicate that these four energetic salts are less sensitive than 1,3,5-trinitrotriazacyccohexane（RDX） and 1,3,5,7- tetranitrotetraqza-cyclo-octane（HMX）.