Understanding the exohedral reactivity of metallofullerenes is crucial for its application in various fields. By systematically controlling the trapped species inside the fullerene its reactivity can be tamed. In this work we report the preferential position of 3d metal atoms inside the C36 cage and their effect on exohedral reactivity in comparison with the neutral and the dianionic cage. The Diels‐Alder (DA) reaction between butadiene and all non‐equivalent [5‐5], [6‐5] and [6‐6] C‐C bonds on the fullerene cage was considered for the analysis, by using density functional theory at the S12g/TZ2P level including COSMO solvation model to elucidate the complete mechanistic pathways. Our results indicate that the preferential position of the metal ion is at the position close to the upper hexagon, and that the general trend in the reactivity of bonds follows the order [5‐5] > [6‐5] > [6‐6]. Moreover, the encapsulation of metal atoms further enhances the reactivity of these bonds, by distorting the system and delocalizing the LUMOs all over the cage.

中文翻译：

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内面金属富勒烯 C36 的外面 Diels-Alder 反应性


了解金属富勒烯的外嵌反应性对于其在各个领域的应用至关重要。通过系统地控制富勒烯内部捕获的物质，可以抑制其反应性。在这项工作中，我们报告了 C36 笼内 3d 金属原子的优先位置以及与中性和双阴离子笼相比它们对外面反应性的影响。通过使用密度泛函分析，考虑了丁二烯与富勒烯笼上所有非等价的[5-5]、[6-5]和[6-6] C-C键之间的狄尔斯-阿尔德(DA)反应。 S12g/TZ2P 水平的理论，包括 COSMO 溶剂化模型，以阐明完整的机制途径。我们的结果表明，金属离子的优先位置位于靠近上六边形的位置，并且键的反应性的总体趋势遵循以下顺序：[5-5] > [6-5] > [6-6 ]。此外，金属原子的封装通过扭曲系统并使整个笼子上的 LUMO 离域，进一步增强了这些键的反应性。