Studies On Tetrazolate Energetic Complexes Of Transition Metals: Preparation And Properties

In order to study new energetic complexes and to develop new primary explosives satisfying the ammunition’s need for miniaturization and modernization,bivalent transition metals Mn（II）、Co（II）、Ni（II）、Cu（II）、Zn（II）、Cd（II）were chosen as center to be coordinated by different ligands:methyl carbazate（MCZ,N%=31.1%）,1-methyl-5-amine-1H-tetrazole（MAT,N%=70.7%）,5,5’-bi-1H-tetrazole（H₂BT,N%=81.1%）and et al.Three serials of energetic complexes of different anions（Cl O₄^-,BT^-,and N₃^-）were prepared for first time.The result indicates that no complexes with Cu（II）as center show largest potential to be used as primary explosives.All the energetic complexes were fully characterized by single crystal X-ray diffraction,elemental analysis,and FT-IR spectroscopy.Furthermore,the thermal stabilities,sensitivities and detonation performance were studied by particular methods.The initiating abilities of some copper-centered complexes for RDX were investigated.[Cu₄（MAT）₂（N₃）₈（H₂O）]_n（21）poccesses the strongest initiating ability.So the synthesis process of[Cu₄（MAT）₂（N₃）₈（H₂O）]_n（21）was optimized.The main contents of the researches are as follows:（1）Six transition metal complexes using 5,5’-bi-1H-tetrazole anions(BT^2-)as outer were designed and synthesized,of which five crystals were gotten:[Mn（H₂O）₆]（HBT）₂·H₂O（1）,[Cu（H₂O）BT]_n（4）,[Zn（H₂O）₂BT]_n（5）,[Cd（H₂O）₂BT]_n（6）.[Cu（TAGH）（HBTA）（H₂O）Cl]Cl·2H₂O（7）was synthesized as comparison.The complexes were fully characterized by single crystal X-ray diffraction,elemental analysis,and FT-IR spectroscopy.And their thermal properties were investigated through differential scanning calorimetry（DSC）and thermogravimetry（TG）.The non-isothermal kinetics parameters and thermodynamic parameters were calculated by specific methods.Besides,impact sensitivities,friction sensitivities,and 5s explosive points were measured.The 5s explosive points of the complexes were between 172?C～414?C.None of（1）～（7）can initiate crystallized RDX.All the complexes except for[Cu（H₂O）BT]_n（4）(H₅₀=34cm;FS:100%)are insensitive towards impact and friction.（2）Nine transition metal complexes using perchloric（Cl O₄^-）as anions[Mn（MCZ）₃]（Cl O₄）₂（8）,[Co（MCZ）₃]（Cl O₄）₂·0.27H₂O（9）,[Ni（MCZ）₃]（Cl O₄）₂·0.18H₂O（10）,[Cu（MCZ）₂（Cl O₄）₂]（11）,[Zn（MCZ）₃]（Cl O₄）₂·0.45H₂O（12）,[Cd（MCZ）₃]（Cl O₄）₂（13）,[Cu（M-AT）₄（H₂O）₂]（Cl O₄）₂（14）,[Cu（H₂BTM）₂（H₂O）₂]（Cl O₄）₂（15）,[Ni（H₂BTE）₂（H₂O）₂]（Cl O₄）₂·2H₂O（16）was designed and prepared,in which the ligands are methyl carbazate（MCZ）,bis（tetrazol-5-yl）ethane（H₂BTE）,bis（tetrazol-5-yl）methane（H₂BTM）.All the co-mplexes were fully characterized by single crystal X-ray diffraction,elemental analysis,and FT-IR spectroscopy.And their thermal properties were investigated through differential scanning calorimetry（DSC）and thermogravimetry（TG）.The non-isothermal kinetics parameters and thermodynamic parameters were calculated by specific methods.Besides,impact sensitivities,friction sensitivities,and 5s explosive points were measured.The 5s explosive points of the complexes were between 177?C～261?C.None of（8）～（16）can initiate crystallized RDX.The order of their impact sensitivities are（15）>（13）>（11）>（16）>（10）>（14）>（9）>（8）>（12）,the friction sensitivities are（11）/（13）>（15）>（14）/（16）>（10）>（9）>（12）>（8）.（3）Seven transition metal complexes using azides（N₃^-）as anions and1-methyl-5-amine-1H-tetrazole（MAT）as ligands were designed and synthesized success-fully,of which four crystal structures were gotten:Mn（MAT）₂（N₃）₂]_n（17）,{[Co₃（MAT）₄（N₃）₂]·2H₂O}_n（18）,[Cu₂（MAT）₂（N₃）₄]_n（20）,[Cu₄（MAT）₂（N₃）₈（H₂O）]_n（21）.Besides,a new ethanediamine（en）complex using azides（N₃^-）as anions[Cu₁₀（en）₄（N₃）₂₀]_n（24）was synthesized.The complexes were fully characterized by single crystal X-ray diffraction,elemental analysis,and FT-IR spectroscopy.The non-isothermal kinetics parameters and thermodynamic parameters were calculated by specific methods.Besides,impact sensitivities,friction sensitivities,and 5s explosive points were measured.And their thermal properties were investigated through differential scanning calorimetry（DSC）and thermogravimetry（TG）.The5s explosive points of the complexes were between 214?C～379?C.Only copper-centered complexes have impact sensitivities,the order of which are（21）>（20）>（24）.And the order of the friction sensitivities are（21）>（24）>（20）>（17）>（18）.Only[Cu₄（MAT）₂（N₃）₈（H₂O）]_n（21）can initiate crystallized RDX successfully.（4）Since[Cu₄（MAT）₂（N₃）₈（H₂O）]_n（21）shows the enormous potential as primary explosives,the synthesis process of it was optimized.Eight common surfactants CMC-Na,PAM,HJ,T40、T60,T80,S80 and SDBS were tried to study their affect to the properties such as productive rate and crystal form of the products.The results indicated that the order of their effects is S80>T60>T40>CMC-Na>T80>PAM>HJ>SDBS.Finally,the products using S80 as additive were fully characterized by EA,PXRD and FT-IR.The impact sensitivity,friction sensitivity and electrostatic sensitivity were measured.The initiating ability of compound 21 was tested again,which shown 10mg of compound 21 can initiate RDX successfully.The research data lay the foundation of its further application.（5）Comparing the three types of anions,the complexes using Cl O₄^-as anions have higher impact sensitivities and friction sensitivities,while the complexes using BT^2-as anions show higher thermal stability.As for the complexes using N₃^-as anions,they usually have medium impact sensitivities,friction sensitivities and thermal stability.Complexes using Cu（II）as center ions show the potential as new primary explosives.[Cu₂（MAT）₂（N₃）₄]_n（20）poccesses stronger initiating ability than NHN primary explosive.[Cu₄（MAT）₂（N₃）₈（H₂O）]_n（21）have as strong initiating ability as lead azide（LA）.These studies provide the possibilities to developing new primary explosives through modifying copper azide（CA）on molecular level with complexation.