Thorium encapsulated metallofullerenes (Th-EMFs) with external C₇₆, C₈₀, C₈₂, and C₈₆ cages have been synthesized, with the ¹³C-NMR spectrum recorded for Th@C₈₂. Here, we explore computationally the chemical bonding, NMR and spherical aromaticity of Th@C₈₂ and related thorium-encapsulated metallofullerenes. Our results show that these Th-EMFs are new examples of spherical aromatic structures, representing interesting low-symmetry exceptions to the Hirsch 2(N + 1)² rule of spherical aromaticity. Their electronic structures are based on π-electron counts of 80, 84, 86, and 90, respectively, with a shell structure ranging from S²P⁶D¹⁰F¹⁴G¹⁸H²²I⁸ to S²P⁶D¹⁰F¹⁴G¹⁸H²²I¹⁸, where the partially filled I-shell remains as a frontier orbital. Their behavior is comparable to that of the spherical aromatic alkali-C₆₀⁶⁻ phases, which in addition to the favorable endohedral Th-fullerene bonding account for their particular abundance exhibiting the ability to sustain a long-range shielding cone as a result of the favorable metal–cage bonding. This rationalization of such species as neutral spherical aromatic EMFs suggests the possibility of an extensive series of aromatic fullerenes with nuclearity larger than C₆₀ buckminsterfullerene as stable building blocks towards nanostructured metal–organic materials.

中文翻译：

---

Th @ C86，Th @ C82，Th @ C80和Th @ C76：of封装在确定中型内面金属富勒烯的球形芳烃和键合特性中的作用

合成了带有外部C ₇₆，C ₈₀，C ₈₂和C ₈₆笼的包裹的金属富勒烯（Th-EMFs），并记录了Th @ C ₈₂的¹³ C-NMR光谱。在这里，我们以计算方式探索Th @ C ₈₂和相关的metal包裹的金属富勒烯的化学键，NMR和球形芳族化合物。我们的结果表明，这些Th-EMF是球形芳香结构的新示例，代表了Hirsch 2（N +1）^2的有趣的低对称性例外球形芳香性的规则。它们的电子结构分别基于π电子数80、84、86和90，壳结构范围从S ² P ⁶ D ¹⁰ F ¹⁴ G ¹⁸ H ²² I ⁸到S ² P ⁶ D ¹⁰ F ¹⁴ G ¹⁸ H ²² I ¹⁸，其中部分填充的I壳保留为前沿轨道。它们的行为与球形芳香碱C ₆₀ ⁶⁻相当由于有利的金属-笼式键合，其相的丰度表现出能够维持远距离屏蔽锥的能力，这些相除了有利于内面的Th-富勒烯键合外，还具有特殊的丰度。这种物种如中性球形芳族EMF的合理化表明，可能存在一系列核比C ₆₀ buckminsterfullerene大的芳族富勒烯，这是形成纳米结构金属有机材料的稳定基础。