The recent successful preparation of infinitene has sparked widespread attention due to its aesthetic appeal and synthetic challenge. Spectroscopic measurements and follow-up computational investigations suggest that infinitene holds fundamental significance and potential applications in chiroptics, optoelectronics, asymmetric synthesis, and supramolecular chemistry. However, unlike other looped polyarenes enriched with sizes and shapes, the infinitene molecule seems, so far, the only known example of this fascinating new form of nanocarbons, whose further exploitation would be considerably limited because of the lack of molecular diversity. Here, we introduce a whole new family of generalized infinitenes with different sizes and topologies. Three types of infinitene structures are rationally designed by joining two units of coronene, kekulene, or their extended analogs. The constructed molecules of varying sizes, each with a large number of possible topoisomers, are systematically studied by DFT calculations. Comprehensive analysis using a simple energy decomposition model uncovers that the stability of infinitenes is governed by the interplay among π delocalization, steric strain, and π–π stacking. While the first two factors are crucial to the stability of smaller infinitenes, the latter is the primary stabilizing interaction for larger infinitenes. Most importantly, we show that larger-sized infinitenes are actually the energetically most favorable form among all known looped polyarenes; their substantial thermodynamic stability surpassing that of circulenes, various carbon nanobelts, and kekulene-like macrocycles renders them promising targets for synthesis. The simulated ¹H NMR, UV–vis, and circular dichroism spectra along with optical rotations for the most stable infinitene species may help their identification in future synthetic efforts.

中文翻译：

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无限烯作为最稳定的环芳烃形式：π 离域、应变和 π-π 堆积之间的相互作用

最近成功制备的无限烯因其美学吸引力和合成挑战而引起广泛关注。光谱测量和后续计算研究表明，无限烯在手性光学、光电子学、不对称合成和超分子化学中具有重要意义和潜在应用。然而，与其他尺寸和形状丰富的环状聚芳烃不同，无限烯分子到目前为止似乎是这种迷人的新型纳米碳的唯一已知例子，由于缺乏分子多样性，其进一步开发将受到相当大的限制。在这里，我们介绍了一个全新的具有不同大小和拓扑结构的广义无穷大系列。通过连接两种晕烯、凯库烯、或他们的扩展类似物。通过 DFT 计算系统地研究了不同大小的构造分子，每个分子都有大量可能的拓扑异构体。使用简单能量分解模型的综合分析表明，无穷大的稳定性受 π 离域、空间应变和 π-π 堆积之间的相互作用控制。虽然前两个因素对较小无穷大的稳定性至关重要，但后者是较大无穷大的主要稳定相互作用。最重要的是，我们表明，在所有已知的环状聚芳烃中，更大尺寸的无穷大实际上是能量上最有利的形式；它们的热力学稳定性超过了环烯、各种碳纳米带和类似凯库烯的大环化合物，这使它们成为有希望的合成目标。模拟的¹ H NMR、UV-vis 和圆二色光谱以及最稳定的无穷大物种的旋光度可能有助于在未来的合成工作中识别它们。