Quantum-chemical calculations of the metallofullerene yields in the X@C74, L@C74, and Z@C82 series

M@C78 (M = U, Th): Inherent Topological Connectivity Existed in Thermodynamically Stable Isomers and the Possibility of an Endohedral Fullerene Containing One Heptagon Ring

“…Numerous previous studies have demonstrated that two electrons are generally transferred from the metal atoms to the fullerene cages for alkaline-earth metal- and some lanthanide metal-based metallofullerenes, while other lanthanide metals and some transition metals such as Sc and Y metals would donate three electrons to the fullerene carbon cages. − In recent years, the experimenters paid attention to actinide-based EMFs, since actinide elements have different physical/chemical properties compared to lanthanide elements due to their active 5f orbitals. However, research on actinide-based EMFs is somehow complex because their electronic structure is quite intriguing.…”

Encapsulation of Monometal Uranium into Fullerenes C2n(2n= 70–74): Important Ionic U4+C2n4–Characters and Covalent U-Cage Bonding Interactions

“…In the case of mono-EMFs, the previous explorations were mainly focused on metal atoms in groups II, III and also the lanthanide-based EMFs for the most fullerene cages. For example, when some rare-earth metals such as Sc, La, Y, Pr, Gd, and Lu are encapsulated, three electrons can transfer from metal to carbon cages. − But for alkaline-earth and other lanthanide metals such as Mg, Ca, Sr, Ba, Sm, Eu, and Yb, two electrons are transferred to fullerenes with the formal structures of M 2+ @C 2 n 2– . − It should be noted that reports on syntheses and characterizations of actinide mono-EMFs are quite limited due to the complicated oxidation state and high radioactivity of the actinide elements until today. In 1992, Smalley and co-workers reported the X-ray photoelectron spectroscopy (XPS) of U@ T d -C 28 , and theoretical calculations indicated that there are four electrons that could be transferred from the uranium atom to this small carbon cage, following calculations and bonding features also verified it by Alvaro Munoz-Castro and co-workers in 2017 .…”