3⁃五唑基吡啶及其衍生物作为N_(5)^(-)离子前体的理论研究  

A Theoretical Study on 3⁃Pentazolylpyridine and its Derivatives as the Precursors of N_(5)^(-) ion

作　　者：袁万里 江毕涛 章冲[1] 孙呈郭[1] 高超 胡炳成[1] 杜杨[1] YUAN Wan-li;JIANG Bi-tao;ZHANG Chong;SUN Cheng-guo;GAO Chao;HU Bing-cheng;DU Yang(School of Chemistry and Chemical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学化学与化工学院,江苏南京210094

出　　处：《含能材料》2022年第12期1237-1244,共8页Chinese Journal of Energetic Materials

基　　金：国家自然科学基金(21903044,11972178,21975128)。

摘　　要：高能五唑离子盐的合成是含能材料领域的研究热点,五唑阴离子的制备是合成高能五唑离子盐的关键步骤。为了拓宽五唑阴离子的来源,寻求稳定性更好,性能更优的五唑阴离子前体,采用密度泛函理论计算研究了3‑五唑基吡啶及其衍生物的桥连C—N键和五唑环的稳定性。结果表明:除—OH、—OMe、—N(Me)_(2)对位取代物外,3‑五唑基吡啶及其—NO_(2)、—CN、—NF_(2)对位取代,—NO_(2)、—CN、—NF_(2)、—OH、—OMe、—N(Me)_(2)间位取代,—NO_(2)、—CN、—NF_(2)、—OH、—OMe、—N(Me)_(2)对位和间位双取代物的桥连C—N键断裂所需的能量E_(a1)均小于苯基五唑,说明这些化合物比苯基五唑更易于得到五唑阴离子。—OMe、—N(Me)_(2)对位取代,—OMe、—N(Me)_(2)间位和对位双取代物的五唑环破裂的能垒E_(a2)与苯基五唑相当,说明这些化合物的五唑环具有较好的稳定性。—N(Me)_(2)间位取代物的E_(a1)和E_(a2)的差值ΔE最小,说明该化合物在切断桥连C—N键获得N_(5)^(-)离子过程中,最易维持五唑环的稳定。相比于苯基五唑,—N(Me)_(2)间位取代和双取代的3‑五唑基吡啶具有较低的ΔE_(a1)、较高的ΔE_(a2)和较低的ΔE,说明其具有替代苯基五唑作为五唑阴离子前体的潜力。The preparations of high‑energy pentazolate salts is a research hotspot in the field of energetic materials.The prepara‑tion of pentazolate anion is a key step in the preparations of high‑energy pentazolate salts.However,as the important precursors for pentazolate anion,the stability of existing arylpentazoles is generally not high.In order to develop new precursors of pentazo‑late anion with better properties,18 substituted derivatives of PyN_(5) with the electron‑withdrawing and electron‑donating groups,i.e.,R‑PyN_(5)(R=-NO_(2),-CN,-NF_(2),-OH,-OMe,-N(Me)_(2)),were designed and studied by using the density functional theory method.The bond dissociation energy(EBD),and the activation energy(E_(a1))of the bridged C—N bond and the activation energy(E_(a2))of the cracking of the N_(5) ring were calculated,and the stability of the bridged C—N bond and pentazolate ring were discussed.E_(a1) of all molecules is smaller than EBD,indicating that the breakage of the bridged C—N bond is more likely to follow the path _(2) rather than path 1.E_(a2) of all molecules is smaller than E_(a1),indicating that the stability of the N_(5) ring is the key factor to determine the stability of the arylpentazoles.Compared with PhN_(5),—N(Me)_(2) meta‑substituted and bis‑substituted compounds have lower E_(a1),higher Ea_(2) and lowerΔE(E_(a2)-E_(a1)).Therefore,—N(Me)_(2) meta‑substituted and bis‑substituted compounds are the most potential precursors of N_(5)^(-)ion for replacing PhN_(5).

关 键 词：五唑阴离子前体 密度泛函理论 稳定性 

分 类 号：TJ55[兵器科学与技术—军事化学与烟火技术]