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).

New multicomponent reactions involving an isocyanide, terminal or internal alkynes, and endohedral metallofullerene (EMF) Lu3N@C80 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 Lu3N 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.

No abstract

Halogenation has been one of the most used strategies to explore the reactivity of empty carbon cages. In particular, the higher reactivity of non-IPR fullerenes, i.e., those fullerenes that do not satisfy the isolated pentagon rule (IPR), has been used to functionalize and capture these less stable fullerenes. Here, we have explored the stability of the non-IPR isomer C(11188) with C symmetry, which is topologically linked to the only IPR isomer of C, as well as its reactivity to chlorination. DFT calculations and Car-Parrinello molecular dynamics simulations suggest that chlorination takes places initially in nonspecific sites, once carbon cages are formed. When the temperature in the arc reactor decreases sufficiently, Cl atoms are trapped on the fullerene surface, migrating from not-so-favored positions to reach the most favored sites in the pentalene. We have also discussed why cage C-C(11188) is found to take four chlorines, whereas cage C-C(14049) is observed to capture 10 of them, even though these two fullerenes are closely related by a simple C insertion.

Endohedral metallofullerenes (EMF), i.e. fullerenes that contain metal atoms or metal clusters in their inner void space, have been intensively studied since the isolation of La@C82.1 In 1999, the synthesis and characterization of the first clusterfullerene Sc3N@C80 using the Krätschmer-Huffman method was a milestone in the field of EMF.2 Since this pioneering work, many EMF have been obtained and characterized,3 among them actinide endofullerenes,4 as for example the dimetallic U2@C80.5 In this compound, the metal-metal distance from X-ray diffraction was found to be ranged between 3.46 and 3.79 Å, quite a long bond distance to suppose the presence of a strong metal-metal bond, as observed previously for dimetallic (lanthanide)2@C2n. This experimental confirmation of a weak U-U bonding interaction in a molecular structure is certainly very encouraging, but we were wondering whether it is possible to isolate a compound with a strong U-U bond or not. In this communication we analyze the characteristic electronic structure of a family of endohedral actinidofullerenes related to U2@C80 and discuss about the challenging task of synthesizing new systems showing strong actinide-actinide interaction in the confined space of a fullerene. References 1. Chai, Y.; Cuo, T.; Jin, C.; Haufler, R. E.; Felipe Chibante, L. P.; Fure, J.; Wang, L.; Alford, J. M.; Smalley, R. E. J. Phys. Chem. 1991, 95, 7564-7568. 2. Stevenson, S.; Rice, G.; Glass, T.; Harich, K.; Cromer, F.; Jordan, M. R.; Craft, J.; Hadju, E.; Bible, R.; Olmstead, M. M.; Maitra, K.; Fisher, A. J.; Balch, A. L.; Dorn, H. C., Nature 1999, 401, 55. 3. Popov, A. A.; Yang, S.; Dunsch, L. Chem. Rev. 2013, 113, 5989-6113. 4. a) Wang, Y.; Morales-Martínez, R. et al.J. Am. Chem. Soc., 2017, 139, 5110-5116; b) Cai, W. C.; Morales-Martínez, R. et al. Chem. Sci. 2017, 8, 5282-5290; c) Cai, W.; Abella, L. et al.J. Am. Chem. Soc., 2018, 140, 18039-18050. 5. Zhang, X.; Wang, Y.; Morales-Martínez, R.; Zhong, J.; de Graaf, C.; Rodríguez-Fortea, A.; Poblet, J. M.; Echegoyen, L.; Feng, L.; Chen, N. J. Am. Chem. Soc., 2018, 140, 3907-3915.