By means of density functional theory calculations, the encapsulation capabilities of a series of azobenzen-containing photoresponsive nanoring hosts (labeled as host 1, 2, 3, 4, 5 and 6 according to the number of the azo unit, respectively) for fullerene C₆₀ were surveyed. Interestingly and abnormally, it is found that the host 5, of which the diameter is only 1.218 nm, can form stable full inclusion complex with C₆₀. However, irrespective of their cavity sizes (11.98 ~ 12.94 Å) of the hosts, the structures 1 ~ 4 and 6 were all disable to form inclusion complex with C₆₀. In this paper, the group-number-composition-selective full inclusion host-guest interaction of the azobenzene-containing nanorings with fullerene C₆₀ is firstly presented. The calculated interaction energies, together with the detection and visualization of the weak interaction regions, provided evidences for the host-guest binding based on relative strong repulsion interaction in the full inclusion complex. Analysis on the frontier orbital feature of the host-guest systems suggests that under the electron excited condition, the chemical activity may be transferred from host 5 to guest C₆₀ by formation of the floating host-guest complex, and the chemical reactivity of the host 5 can be passivated via formation of the full inclusion host-guest complex. Additionally, UV–vis–NIR and ¹H NMR spectra of the hosts before and after the formations of the complexes have been simulated and discussed qualitatively, which may be helpful for further experimental investigations in future.

中文翻译：

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含偶氮苯的光响应纳米环与富勒烯 C60 的成分选择性全包合主客体相互作用

通过密度泛函理论计算，一系列含偶氮苯的光响应纳米环主体（根据偶氮单元的数量分别标记为主体1、2、3、4、5和6 ）对富勒烯C的包封能力对₆₀人进行了调查。有趣且异常地发现，直径仅为1.218 nm的主体5可以与C ₆₀形成稳定的全包合物。然而，无论主体的空腔大小（11.98 ~ 12.94 Å）如何，结构1  ~ 4 和6_{均不能与C 60}形成包合物。本文首次提出了含偶氮苯纳米环与富勒烯C _{60的基团数组成选择性全包合主客体相互作用。}计算的相互作用能，以及弱相互作用区域的检测和可视化，为基于全包合物中相对强排斥相互作用的主客体结合提供了证据。对主客体系统前沿轨道特征的分析表明，在电子激发条件下，通过形成浮动的主客体复合物，以及主体的化学反应性，化学活性可能从主体5转移到客体C _{60 。}5可以通过形成完全包含的主客体复合物来钝化。此外，对配合物形成前后主体的紫外-可见-近红外和^{1 H NMR 光谱进行了模拟和定性讨论，这可能有助于未来的进一步实验研究。}