%0 Journal Article
%T <br>
%A 乔成芳
%A 吕磊
%A 周春生
%A 夏正强
%A 许文风
%A 陈三平
%A 高胜利
%J 物理化学学报
%D 2020
%R 10.3866/PKU.WHXB201905085
%X 溶剂分子的存在会严重降低能量金属-有机框架(EMOFs)材料的爆热和稳定性，开发无溶剂的EMOFs已成为制备高能量密度材料的有效策略。本文将高能的2, 3-二(5-1H-四唑基)吡嗪(H2DTPZ)配体与银离子作用在水热条件下制备了一例无溶剂的EMOF [Ag2(DTPZ)]n (1) (含氮量: 32.58%)，并借助元素分析、红外光谱、X射线衍射以及热分析等技术对其组成和结构进行了表征。化合物1中，DTPZ2？配体构型高度扭转并以八齿配位模式桥联Ag+离子形成三维框架结构(ρ = 2.812 g？cm？3)，配体大的位阻效应和强的配位能力有效阻止了溶剂分子与金属配位或占据框架空腔；同时，不同配体四唑环间强的π-π堆积作用(质心-质心距离为0.34461(1) nm)，使得化合物1呈现高的热稳定性(Te = 619.1 K, Tp = 658.7 K)。热分析研究表明化合物1分解主要发生一步快速失重并伴有剧烈的放热，呈现出潜在的含能特质。通过差示扫描量热(DSC)技术对化合物1的热分解过程进行了非等温热动力学分析(基于Kissinger和Ozawa-Doyle方法)并获得了相应热动力学参数(活化能Ea = 272.1 kJ·mol？1，Eo = 268.9 kJ·mol？1；lgA =19.67 s？1)。进一步基于升温速率趋于0时的分解峰温和外延起始温度，计算得到了相关热力学参数(活化焓ΔH≠ = 266.9 kJ·mol-1，活化熵ΔS≠ = 125.4 J·mol？1·K？1，活化自由能ΔG≠ = 188.3 kJ·mol？1)以及热爆炸临界温度(Tb = 607.1 K)和自加速分解温度(TSADT = 595.8 K)，结果表明该化合物具有良好的热安全性，其分解属非自发的熵驱动过程。借助精密转动弹热量计测定了化合物1的恒容燃烧能(Qv)并计算得其标准摩尔生成焓为(2165.99 ± 0.81) kJ·mol？1。爆轰和安全性能测试表明，化合物1对撞击和摩擦均不敏感，爆热值达10.15 kJ·g？1，远高于常见硝铵类炸药奥克托金(HMX)、黑索金(RDX)和2, 4, 6-三硝基甲苯(TNT)，是一例有前景的高能钝感含能材料。<br>Solvent molecules can significantly reduce the heat of detonation and stability of energetic metal-organic framework (EMOF) materials, and the development of solvent-free EMOFs has become an effective strategy to prepare high-energy density materials. In this study, a solvent-free EMOF, [Ag2(DTPZ)]n (1) (N% = 32.58%), was synthesized by reacting a high-energy ligand, 2, 3-di(1H-tetrazol-5-yl)pyrazine (H2DTPZ), with silver ions under hydrothermal conditions, and it was structurally characterized by elemental analysis, infrared spectroscopy, X-ray diffraction, and thermal analysis. In 1, the DTPZ2？ ligands that adopted a highly torsional configuration bridged the Ag+ ions in an octadentate coordination mode to form a three-dimensional framework (ρ = 2.812 g？cm？3). The large steric effect and strong coordination ability of DTPZ2？ effectively prevented the solvent molecules from binding with the metal centers or occupying the voids of 1. Moreover, the strong π-π stacking interactions [centroid-centroid distance = 0.34461(1) nm] between the tetrazole rings in different DTPZ2？ ligands provided a high thermal stability to the framework (Te = 619.1 K, Tp = 658.7 K). Thermal analysis showed that a one-step rapid weight loss with intense heat release primarily occurred during the decomposition of 1, suggesting potential energetic characteristics. Non-isothermal thermokinetic analyses (based on the Kissinger and Ozawa-Doyle methods) were performed using differential scanning calorimetry to obtain the thermoanalysis kinetic parameters of the thermodecomposition of 1 (Ea = 272.1 kJ·mol？1, Eo = 268.9 kJ·mol？1; lgA =19.67 s？1). The related
%U http://www.whxb.pku.edu.cn/CN/Y2020/V36/I6/1905085