Chen Xuyang, Sun Yuanyuan, Wang Yang
School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China.
J Org Chem. 2022 Aug 19;87(16):10755-10767. doi: 10.1021/acs.joc.2c00970. Epub 2022 Aug 5.
Since its atomically precise synthesis in recent experiments, the carboncone molecule presents a novel example of discrete nanocarbons with promising applications, but little is known yet about its chemical properties. In this work, we present a comprehensive computational study on the hydrogenation of carboncone with a varying number of added H atoms (from 1 to 12). Unlike planar benzenoid hydrocarbons, carboncone prefers that all H atoms be added to its external, convex surface. The previous topology-based model for hydrogenated fullerenes and benzenoid hydrocarbons is shown to be no longer valid for carboncone. We here propose an extended model capable of predicting the hydrogenation regioselectivity for carboncone, which is largely governed by π delocalization. Yet the H···H repulsion at rim sites also plays an important role in adduct stability. Interestingly, some preferred addition patterns can be understood by counting the size of intact π rings upon H addition. These findings may provide insightful guidance to the functionalization of carboncones and related nanocarbons.
自从在最近的实验中实现原子精确合成以来，碳锥分子成为具有潜在应用前景的离散纳米碳的一个新例子，但人们对其化学性质仍知之甚少。在这项工作中，我们对添加不同数量H原子（从1到12）的碳锥氢化进行了全面的计算研究。与平面苯型烃不同，碳锥更倾向于将所有H原子添加到其外部凸表面。先前基于拓扑的氢化富勒烯和苯型烃模型对碳锥不再有效。我们在此提出一个扩展模型，能够预测碳锥的氢化区域选择性，其主要由π离域控制。然而，边缘位置的H···H排斥在加合物稳定性中也起着重要作用。有趣的是，一些优先的加成模式可以通过计算H加成后完整π环的大小来理解。这些发现可能为碳锥及相关纳米碳的功能化提供有见地的指导。
