A new carbonaceous nanohoop, [4]cyclopara-1,2-diphenylethylene ([4]CPDPE, composed by four 1,2-diphenylethylene units linked via the para of the phenyls), is designed together with two rational synthesis paths being proposed. The Saturn-like host–guest systems formed with the [4]CPDPE nanoring and fullerene C_60/70 are explored using density functional theory calculations. The results evidence that the geometry mutual matching between [4]CPDPE and C_60/70 is perfect, and the [4]CPDPE⊃C_60/70 complexes could be formed spontaneously with high binding energies. Thermodynamic calculation results show that it essentially prefers to selectively recognize C₇₀ over its smaller cousin C₆₀. More interestingly, the [4]CPDPE nanoring could present the regular ring cylinder and the saddle shapes via configuration transformation between its all-trans form and all-cis form, so as to theoretically realize the fullerene encapsulation and release under photoirradiation. Furthermore, the 2:1 interaction structure ([4]CPDPE₂⊃Dimer-C₆₀) and properties are investigated. Additionally, the ultraviolet–visible (UV–vis) spectra are simulated, and host–guest noncovalent interaction (NCI) regions are investigated based on the electron density and reduced density gradient (RDG), which may be helpful for a deep understanding of the present designed systems in future.

中文翻译：

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基于 C60/70 Bucky Ball 和新设计的 [4]Cyclopara-1,2-diphenylethylene Hoop 的纳米级 Saturn 系统：C70 富勒烯封装释放和选择性识别的策略

设计了一种新的碳质纳米环，[4]cyclopara-1,2-二苯基乙烯（[4]CPDPE，由四个通过苯基的对位连接的 1,2-二苯基乙烯单元组成），并提出了两条合理的合成路径。使用密度泛函理论计算探索了由 [4]CPDPE 纳米环和富勒烯 C _60/70形成的类土星主客体系统。_{结果表明，[4]CPDPE 与 C 60/70}之间的几何相互匹配是完美的，[4]CPDPE⊃C _60/70配合物可以自发​​形成，具有高结合能。热力学计算结果表明，与其较小的表亲 C 60 相比，_它基本上更喜欢选择性地识别 C ₇₀. 更有趣的是，[4]CPDPE纳米环通过其全反式和全顺式的构型转换可以呈现规则的环状圆柱体和马鞍形，从而在理论上实现富勒烯在光辐照下的包封和释放。此外，还研究了2:1 相互作用结构 ([4]CPDPE ₂ ⊃Dimer-C _{60 ) 和性质。}此外，还模拟了紫外-可见 (UV-vis) 光谱，并根据电子密度和约化密度梯度 (RDG) 研究了主客体非共价相互作用 (NCI) 区域，这可能有助于深入了解在未来展示设计的系统。