New Energetic Complexes as Catalysts for Ammonium Perchlorate Thermal Decomposition

In this study,four new energetic complexes(1)[Cu(vimi)_(4)]DCA_(2),(2)[Co(vimi)_(4)]DCA_(2),(3)[Ni(vimi)_(4)]DCA_(2),and(4)[Cu(vimi)_(4)]CBH_(2)(vimi:1-vinylimidazole,DCA:dicyanamide anion,CBH:cyanoborohydride anion)were prepared,and their structures were characterized via single-crystal X-ray diffraction,elemental analysis,and Fourier-transform infrared spectroscopy.The catalytic effects of the complexes on ammonium perchlorate thermal decomposition were studied via thermal analysis methods,including differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA).Among the complexes,complex 2 showed the best catalytic performance.The two decomposition peaks in the DSC curve of the pure ammonium perchlorate-low-temperature decomposition(LTD)peak:2950C and high-temperature decomposition(HTD)peak:418℃-were merged into a lower decomposition peak(325℃)in the curve of AP with complex 2.Moreover,the heat released by ammonium perchlorate with complex 2(1661.7 J g^(-1))was significantly higher than that released by the pure ammonium perchlorate(814.5 J g^(-1)).The kinetic parameters calculated using Kissinger's method revealed that the complexes had a significant effect on the activation energy of ammonium perchlorate decomposition(223.5 kJ mol^(-1)),and complex 2 lowered the activation energy to 115.6 kJ mol^(-1).The results indicate that complex 2 is a potential energetic additive for ammonium perchlorate-based solid propellants.

Enhancing energetic performance of metal-organic complex-based metastable energetic nanocomposites by spray crystallization

Energetic metal-organic complexes have been involved in nanothermites as novel oxidants.However,the existing preparation methods often lead to mixing inhomogeneity and small contact area of ingredients,the reactivity and functionality of the novel energetic nanocomposites are still limited.In this work,spray crystallization(SC)method was used to prepare novel energetic nanocomposites,the high-energy metal-organic complex[Ni(CHZ)_(3)](ClO_(4))_(2)(CHZ=1,3-diaminourea)was composited with nanoaluminum(n-Al).Results showed that n-Al/[Ni(CH_(2))_(3)](ClO_(4))_(2)energetic nanocomposites prepared by SC method increased heat release to 2977.6 J/g and peak pressure to 3.91 MPa with higher pressurization rate(1324.06 MPa/s),decreased sensitivity thresholds(>100 mJ)to electrostatic discharge(ESD)and enhanced detonation ability compared with[Ni(CHZ)_(3)](ClO_(4))_(2)alone and physically mixed(PM)n-Al/[Ni(CHZ)_(3)](ClO_(4))_(2).These results proved that it is significant to introduce energetic metal-organic complexes with inherent high energy in new-concept n-Al/energetic metal-organic complexes nanocomposites through SC method for a better performance of its application.

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.

Comparative DFT Study of [Mg(CHZ)_3](ClO_4)_2 and [Mg(CHZ)_3](NO_3)_2(CHZ=Carbohydrazide)

The molecular geometry,electronic structure,thermochemistry and infrared spectra of [Mg（CHZ）3]（ClO4）2 and [Mg（CHZ）3]（NO3）2 were comparatively studied using the Heyd-Scuseria-Ernzerhof（HSE） screened hybrid density functional with 6-31G＊＊ basis set.The experimental results show that the complexes have six-coordinated octahedron feature,and the metal-ligand interactions are predominantly ionic in nature.The calculated heats of formation predict that [Mg（CHZ）3]（NO3）2 is more stable than [Mg（CHZ）3]（ClO4）2.Detailed NBO analyses indicate that the ligand-anion interaction plays an important role in the stability for these two energetic complexes.Moreover,the stretching vibration frequencies of N-H bonds shift to lower wave number compared to the free CHZ ligand,which are caused by the delocalizations from N-H bond orbital to lone-pair electron antibond orbital of magnesium.