Chemically Reactive Species Remain Alive inside Carbon Nanotubes: A Density Functional Theory Study
Chemically Reactive Species Remain Alive inside Carbon Nanotubes: A Density Functional Theory Study
复制标题
化学反应物质在碳纳米管内保持活性：密度泛函理论研究
DOI：
10.1039/c0cp00796j
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发表时间：
2011
影响因子：
3.3
通讯作者：
T.
中科院分区：
文献类型：
--
作者：
Yumura;T.
利用密度泛函理论（DFT）分析了不同直径碳纳米管主体内烷基客体自由基的行为。在这里，假定内部的烷基自由基是由它们的前体分解形成的，前体被纳入管中。DFT计算表明，内部烷基自由基倾向于与纳米管壁分离存在（分离形式），而不是与管壁形成内部共价键（结合形式）。使自由基远离内壁更有可能使体积更大的自由基在直径更小的管内。分离形式优于束缚形式的一个关键是，束缚形式由于与内壁形成键而获得弱吸引力。由于内表面的惰性而产生的弱吸引力，被主客耦合引起的管和自由基变形所引起的不稳定所抵消。能量平衡的论点说明，内壁的惰性使烷基自由基在管内保持活性并保持其反应性。这些发现可以帮助我们理解实验结果，即在客人被激活后，试管内的化学反应会进行。
The behavior of alkyl guest radicals inside carbon nanotube hosts with different diameters is analyzed using density functional theory (DFT) calculations. Here the inner alkyl radicals are assumed to be formed by decomposition of their precursors, which had been incorporated into the tubes. DFT calculations show that inner alkyl radicals prefer to exist separately from the nanotube wall (separate form) rather than forming an inner covalent bond with the wall (bound form). Keeping a radical apart from the inner wall is more likely for a more bulky radical inside a smaller diameter tube. A key to the preference for the separate forms over the bound forms is that the bound forms gain a weak attraction due to the formation of a bond with the inner wall. The weak attraction, ascribed to the inertness of the inner surface, is counteracted by destabilization due to deformations of a tube and radical induced by guest–host coupling. The energy balance argument illuminates that the inertness of the inner wall makes an alkyl radical species remain alive inside a tube and retain its reactivity. These findings can help us to understand experimental results where chemical reactions inside a tube proceed after guests are activated.