Wang Luoxin, Zou Hantao, Yi Changhai, Xu Jie, Xu Weilin
Key Laboratory of Green Processing and Functional Textiles of New Textile Materials (Wuhan Textile University), Ministry of Education, Luxiang, Wuhan 430073, P.R. China.
J Nanosci Nanotechnol. 2011 Apr;11(4):3298-305. doi: 10.1166/jnn.2011.3742.
Chemical reactivity and molecular structure of energetic materials may be significantly changed when they are confined inside carbon nanotubes (CNTs). The ONIOM calculations were carried out to investigate the molecular structures and the N-N bond decomposition of nitramide (NA) and methylnitramine (MNA) confined inside armchair single-walled CNTs with different diameter. Results showed that confinement in CNT(6, 6) and CNT(7, 7) had no evident influence on the structure of NA and MNA. However, the structures of NA and MNA within CNT(5, 5) were altered significantly with respect to the structures of the isolated NA and MNA. Compared with NA, MNA showed stronger interaction with these CNTs studied. By analyzing the potential energy curve along the N-N bond, we found that the energy barriers of the N-N bond decomposition for the NA and MNA are decreased by 11.6 and 10.8 kcal/mol, respectively, due to the confinement of CNT(5, 5). Confinement in CNT(6, 6) resulted in a slight decrease in the activation energy. Confinement in CNT(7, 7) did not affect the thermal decomposition of NA and MNA. We conclude that the N-N bond dissociation of NA and MNA can be promoted by confinement in a CNT with small diameter.
当含能材料被限制在碳纳米管（CNT）内部时，其化学反应性和分子结构可能会发生显著变化。进行了ONIOM计算，以研究限制在不同直径的扶手椅型单壁碳纳米管内的硝酰胺（NA）和甲基硝胺（MNA）的分子结构和N-N键分解情况。结果表明，限制在CNT(6, 6)和CNT(7, 7)中对NA和MNA的结构没有明显影响。然而，相对于孤立的NA和MNA的结构，CNT(5, 5)内的NA和MNA的结构发生了显著变化。与NA相比，MNA与所研究的这些碳纳米管表现出更强的相互作用。通过分析沿N-N键的势能曲线，我们发现由于CNT(5, 5)的限制，NA和MNA的N-N键分解的能垒分别降低了11.6和10.8 kcal/mol。限制在CNT(6, 6)中导致活化能略有降低。限制在CNT(7, 7)中不影响NA和MNA的热分解。我们得出结论，限制在小直径的碳纳米管中可以促进NA和MNA的N-N键解离。
