New multicomponent reactions involving an isocyanide, terminal or internal alkynes, and endohedral metallofullerene (EMF) Lu 3 N@C 80 yield metallofulleroids which are characterized by mass-spectrometry, HPLC, and multiple 1D and 2D NMR techniques. Single crystal studies revealed one ketenimine metallofulleroid has ordered Lu 3 N cluster which is unusual for EMF monoadducts. Computational analysis, based on crystallographic data, confirm that the endohedral cluster motion is controlled by the position of the exohedral organic appendants. Our findings provide a new functionalization reaction for EMFs, and a potential facile approach to freeze the endohedral cluster motion at relatively high temperatures.

The electrocatalytic properties of some endohedral fullerenes for hydrogen evolution reactions (HER) were recently predicted by DFT calculations. Nonetheless, the experimental catalytic performance under realistic electrochemical environments of these 0D-nanomaterials have not been explored. Here, for the first time, we disclose the HER electrocatalytic behavior of seven M 3 N@2n (2n = 68, 78, and 80) fullerenes (Gd 3 N@I h (7)-C 80 , Y 3 N@I h (7)-C 80 , Lu 3 N@I h (7)-C 80 , Sc 3 N@I h (7)-C 80 , Sc 3 N@D 5h (6)-C 80 , Sc 3 N@D 3h (5)-C 78 , and Sc 3 N@D 3 (6140)-C 68 ) using a combination of experimental and theoretical techniques. The non-IPR Sc 3 N@D 3 (6140)-C 68 compound exhibited the best catalytic performance toward the generation of molecular hydrogen, exhibiting an onset potential of −38 mV vs RHE, a very high mass activity of 1.75 A•mg −1 at −0.4 V vs RHE, and an excellent electrochemical stability, retaining 96% of the initial current after 24 h. The superior performance was explained on the basis of the fused pentagon rings, which represent a new and promising HER catalytic motif.

Previous characterizations of diactinide endohedral metallofullerenes (EMFs) Th 2 @C 80 and U 2 @C 80 have shown that although the two Th 3+ ions form a strong covalent bond within the carbon cage, the interaction between the U 3+ ions is weaker and described as an "unwilling" bond. To evaluate the feasibility of covalent U−U bonds, which are neglected in classical actinide chemistry, we have first investigated the formation of smaller diuranium EMFs by laser ablation using mass spectrometric detection of dimetallic U 2 @C 2n species with 2n ≥ 50. DFT, CASPT2 calculations, and MD simulations for several fullerenes of different sizes and symmetries showed that thanks to the formation of strong U(5f 3 )-U(5f 3 ) triple bonds, two U 3+ ions can be incarcerated inside the fullerene. The formation of U−U bonds competes with U−cage interactions that tend to separate the U ions, hindering the observation of short U−U distances in the crystalline structures of diuranium endofullerenes as in U 2 @C 80 . Smaller cages like C 60 exhibit the two interactions, and a strong triple U−U bond with an effective bond order higher than 2 is observed. Although 5f−5f interactions are responsible for the covalent interactions at distances close to 2.5 Å, overlap between 7s6d orbitals is still detected above 4 Å. In general, metal ions within fullerenes should be regarded as templates in cage formation, not as statistically confined units that have little chance of being observed.

In this work, two new C70 isomers α and β bis(2-(thiophen-2-yl)ethyl)-C70-fullerene mono-adducts (DTC70) were synthesized, characterized and used as electron transporting materials (ETMs) in perovskite solar cells (PSCs).