Synthesis,Characterization And Properties Of Unsymmetrical Substituted-tetrazine Compounds

Five unsymmetrical substituted tetrazine energetic compounds(or tetrazine compounds with fused rings)were synthesized in this paper and characterized by IR and EA.They are:6-(3,5-dimethyl-1H-pyrazol-1-yl)-3-(hydroxydiazenyl)-[1,2,4]triazolo[4,3-b][1,2,4,5]tetra zine(DPHTTz),1,2-azobis(6-(4-chloro-3,5-dimethyl-1H-pyrazol-1-yl)-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine)(ACDPTTz),3-(1H-1,2,3,4-tetrazol-5-ylamino)-6-(3,5-dimethyl-pyrazol-1-yl)-s-tetrazine(TADPTz),3-(1H-1,2,3,4-tetrazol-5-ylamino)-6-hydrazinyl-s-tetrazine(TAHTz)and 3-amino-6-(1H-tetrazol-5-yl)-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine(ATTTz).Meanwhile,their singal crystals were obtained through appropriate methods.The crystal structures of these five compounds were determined by X-ray singal crystal diffractometer and can be seen as follows:DPHTTz: C8H8N10 O,Orthorhombic,Pna21;ACDPTTz·2DMF: C22H26N20O2Cl2,monoclinic,P21/c;TADPTz: C8H9N11,monoclinic,P21/c;TAHTz·CH3OH: C4H9N11 O,monoclinic,P21/c;3ATTTz·4DMF: C24H40N40O4,triclinic,P-1;Furthermore,the thermal decomposition behaviors of DPHTTz,ACDPTTz,TADPTz,TAHTz and ATTTz were determined by differential scanning calorimetry(DSC)and thermogravimetry(TG)under the condition of non-isothermal.Besides,the Ozawa method,the Kissinger method and the integral methodwere used to caculate the thermal decomposition kinetics parameters and thermal decomposition kinetics equations of DPHTTz,TADPTz,TAHTz and ATTTz.Moreover,the TSADT,Tbe,Tbp,ΔH≠,ΔS≠,ΔG≠ were caculated to evalue the thermal safety of those tetrazine compounds.The detonation velocity and detonation pressure of DPHTTz,TADPTz,TAHTz and ATTTz were also evaluated by nitrogen equivalent equations.Finally,the frontier orbitals,the Mulliken charges and the Mulliken bond orders of above-mentioned compounds were analyzed by Dmol3 in Materials Studio.The results indicate that the fused ring and azo groups can improve the thermal stability of tetrazine compounds.Meanwhile,TAHTz shows the highest detonation properties and ATTTz shows the best thermal stability,both of the two compounds have potential application in new energetic materials.