Fullerenes have the characteristic of a hollow interior, and this unique feature triggers intuitive inspiration to entrap atoms, ions or clusters inside the carbon cage in the form of endohedral fullerenes. In particular, upon entrapping an otherwise unstable metal cluster into a carbon cage, the so-called endohedral clusterfullerenes fulfil the mutual stabilization of the inner metal cluster and the outer fullerene cage with a specific isomeric structure which is often unstable as an empty fullerene. A variety of metal clusters have been reported to form endohedral clusterfullerenes, including metal nitrides, carbides, oxides, sulfides, cyanides and so on, making endohedral clusterfullerenes the most variable and intriguing branch of endohedral fullerenes. In this review article, we present an exhaustive review on all types of endohedral clusterfullerenes reported to date, including their discoveries, syntheses, separations, molecular structures and properties as well as their potential applications in versatile fields such as biomedicine, energy conversion, and so on. At the end, we present an outlook on the prospect of endohedral clusterfullerenes.

中文翻译：

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当金属簇遇到碳笼时：内面簇富勒烯

富勒烯具有中空内部的特征，这种独特的特征触发了直观的灵感，以内嵌富勒烯的形式将原子，离子或团簇捕获在碳笼中。特别地，在将原本不稳定的金属簇捕获到碳笼中时，所谓的内面簇富勒烯通过特定的异构体结构实现内部金属簇和外部富勒烯笼的相互稳定，该异构体通常作为空的富勒烯是不稳定的。据报道，有各种各样的金属团簇形成内表面的富勒烯，包括金属的氮化物，碳化物，氧化物，硫化物，氰化物等，使内表面的簇富勒烯成为内表面富勒烯变化最大，最引人入胜的分支。在这篇评论文章中，我们对迄今为止报道的所有类型的内面簇聚富勒烯进行详尽的综述，包括它们的发现，合成，分离，分子结构和性质，以及它们在生物医学，能量转换等通用领域中的潜在应用。最后，我们对内面簇状富勒烯的前景提出了展望。