Construction And Energetic Characteristics Of Nitrogen-rich Cobalt And Copper Compounds Based On The Enhancement Of Energy Density

This paper aims to solve the contradiction between energy and safety of the energetic compounds.From the coordination chemistry point of view,the work of synthesis,preparation and research of energetic compounds were carried out to achieve the energetic compounds with excellent performance.Based on the above consideration,3-(1H-tetrazol-5-yl)-1H-triazole)(H2tztr)was regarded as the ligand,and Co(II)and Cu(II)metal ions were choosed as the coordinated centers in this paper.Five energetic compounds: {[Co(Htztr)2(H2O)2]·2H2O}n(1)? {[Co4(tztr)4(H2O)2]·2H2O}n(2)?{[Co(tztr)]·0.33H2O}n(3)?{[Cu(Htztr)(H2O)]NO3}n(4)and [Cu(H2tztr)2(HCOO)2]n(5)were attained through the hydrothermal method and solution method.In addition,the structure and related physical and chemical properties have been characterized and analyzed in 1-5.1.The X-ray single crystal diffraction technology,element analysis and Fourier transform infrared spectroscopy characterize structure of the compounds 1-5.The structural analysis indicates that ligand H2 tztr presents different coordination modes under the different conditions.In {[Co(Htztr)2(H2O)2]·2H2O}n(1)and [Cu(H2tztr)2(HCOO)2]n(5),the ligands adopt the bidentate chelating mode to coordinate with Co(II)and Cu(II),forming a mononuclear structure,respectively.The difference is that the ligand removes a proton(Htztr-)in 1,while the ligand is unsripped proton(H2tztr)in 5;In {[Co4(tztr)4(H2O)2]·2H2O}n(2),the ligand adopts a bidentate chelating and three monodentate bridging coordination modes connected with Co(II)to form a three-dimensional frame structure,in which the ligand is present in the form of complete deproton(tztr2-);In {[Co(tztr)]·0.33H2O}n(3),the ligand adopts two bidentate chelating and two monodentate bridging coordination modes connected with Co(II)to form a three-dimensional frame structure,where the ligand is present in the form of complete deproton(tztr2-);In {[Cu(Htztr)(H2O)]NO3}n(4),the ligand adopts a bidentate chelating and two monodentate bridging coordination modes coordinated with Cu(II)to form a two-dimensional structure,where the ligand removes a proton(Htztr-).With the change of the coordination modes in the ligand,the structures of compounds 1-5 also change gradually.2.By using the oxygen bomb calorimeter,the constant volume combustion heat of the compounds 1-5 were measured,and the standard mole formation enthalpy were calculated.The standard molar enthalpy of formation of the compounds 1-5 were 2651.53 ± 3.00 k J mol-1?9467.42 ± 0.11 k J mol-1?2494.32 ± 1.01 k J mol-1?1509.59 ± 1.10 k J mol-1 and 5104.67 ± 0.56 k J mol-1,respectively.It is shown that the thermodynamic stability of the compounds is 2,5,1,3 and 4 from low to high.The combination of thermogravimetric method and differential scanning calorimetry(TG-DSC)to study the thermal decomposition behavior of compounds 1-5.The analysis results show that the thermal decomposition temperature of 1-5 are more than 300 oC,and they have the high thermal stability.Using Kissinger's and Ozawa-Doyle's method,the thermodynamic stability of 1-5 were studied under different temperature conditions,and the apparent activation energies were calculated.Due to the higher activation energies in 2 and 3,they have higher thermodynamic stability than 1,4 and 5.3.The constant volume combustion heat of the compounds 1-5 were measured by using the oxygen bomb calorimeter,and the standard mole formation enthalpy and the detonation heat were calculated.The values of detonation heat of 1-5 range from 2.0051 kcal g-1 to 3.3616 kcal g-1.The detonation velocity and detonation pressure were calculated by the Kamlet-Jacobs(K-J)equation.The detonation velocity and detonation pressure were in the range of 8.26-9.17 km s-1 and 29.87-41.77 GPa,respectively.Moreover,the heat of detonation of the compounds 1-5 were calculated by using the density functional theory(DFT)and Linear correlation equation,the values of detonation heat of 1-5 range from 2.1272 kcal g-1 to 3.5663 kcal g-1.The detonation velocity and detonation pressure of 1-5 were calculated by the K-J equation.The detonation velocity and detonation pressure were in the range of 8.38-9.28 km s-1 and 30.77-42.56 GPa,respectively.Compared with two sets of the detonation heat,the similar values indicate that the density functional theory(DFT)is a reliable algorithm.In addition,the test results indicate that the impact sensitivity and friction sensitivity were greater than 40 J and 360 N in 1-5,respectively.