Dong Yalu, Peng Panpan, Hu Baoping, Su Hui, Li Shenghua, Pang Siping
School of Materials Science & Engineering, Beijing Institute of Technology, Beijing 100081, China.
Molecules. 2017 Jun 26;22(7):1068. doi: 10.3390/molecules22071068.
High-energy metal-organic frameworks (MOFs) based on nitrogen-rich ligands are an emerging class of explosives, and density is one of the positive factors that can influence the performance of energetic materials. Thus, it is important to design and synthesize high-density energetic MOFs. In the present work, hydrothermal reactions of Cu(II) with the rigid polynitro heterocyclic ligands 5,5'-dinitro-2,2'-3,3'-bi-1,2,4-triazole (DNBT) and 5,5'-dinitro-3,3'-bis-1,2,4-triazole-1-diol (DNBTO) gave two high-density MOFs: [Cu(DNBT)(ATRZ)₃] () and [Cu(DNBTO)(ATRZ)₂(H₂O)₂] (), where ATRZ represents 4,4'-azo-1,2,4-triazole. The structures were characterized by infrared spectroscopy, elemental analysis, ultraviolet-visible (UV) absorption spectroscopy and single-crystal X-ray diffraction. Their thermal stabilities were also determined by thermogravimetric/differential scanning calorimetry analysis (TG/DSC). The results revealed that complex has a two-dimensional porous framework that possesses the most stable chair conformations (like cyclohexane), whereas complex has a one-dimensional polymeric structure. Compared with previously reported MOFs based on copper ions, the complexes have higher density (ρ = 1.93 g cm for complex and ρ = 1.96 g cm for complex ) and high thermal stability (decomposition temperatures of 323 °C for complex and 333.3 °C for complex ), especially because of the introduction of an N-O bond in complex . We anticipate that these two complexes would be potential high-energy density materials.
基于富氮配体的高能金属有机框架材料（MOFs）是一类新兴的炸药，密度是影响含能材料性能的积极因素之一。因此，设计和合成高密度含能MOFs具有重要意义。在本工作中，铜（II）与刚性多硝基杂环配体5,5'-二硝基-2,2'-3,3'-联-1,2,4-三唑（DNBT）和5,5'-二硝基-3,3'-双-1,2,4-三唑-1-二醇（DNBTO）进行水热反应，得到了两种高密度MOFs：[Cu(DNBT)(ATRZ)₃]（）和[Cu(DNBTO)(ATRZ)₂(H₂O)₂]（），其中ATRZ代表4,4'-偶氮-1,2,4-三唑。通过红外光谱、元素分析、紫外可见（UV）吸收光谱和单晶X射线衍射对其结构进行了表征。还通过热重/差示扫描量热分析（TG/DSC）测定了它们的热稳定性。结果表明，配合物具有二维多孔框架结构，具有最稳定的椅式构象（类似于环己烷），而配合物具有一维聚合物结构。与先前报道的基于铜离子的MOFs相比，这些配合物具有更高的密度（配合物的ρ = 1.93 g/cm³，配合物的ρ = 1.96 g/cm³）和高热稳定性（配合物的分解温度为323℃，配合物的分解温度为333.3℃），特别是因为配合物中引入了N-O键。我们预计这两种配合物将是潜在的高能量密度材料。
