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The smallest borafullerene U@C27B has been synthesized using a laser vaporization cluster source. The U atom, placed in the middle of the cage and interacting with all the 28 atoms, is formally described as highly oxidized U(vi).

New multicomponent reactions involving an isocyanide, terminal or internal alkynes, and endohedral metallofullerene (EMF) Lu3 N@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 Lu3 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 M3N@2n (2n = 68, 78, and 80) fullerenes (Gd3N@Ih(7)-C80, Y3N@Ih(7)-C80, Lu3N@Ih(7)-C80, Sc3N@Ih(7)-C80, Sc3N@D5h(6)-C80, Sc3N@D3h(5)-C78, and Sc3N@D3(6140)-C68) using a combination of experimental and theoretical techniques. The non-IPR Sc3N@D3(6140)-C68 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.

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). Our results show that the α isomer improves both the Jsc and FF values of the devices, when compared to the results for the β-isomer and to those for phenyl-C70-butyric acid methyl ester (PC71BM), used as control. Devices based on α-DTC70 achieved a power conversion efficiency (PCE) of 15.9%, which is higher than that observed with PC71BM (15.1%).

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

The functionalization of endohedral metallofullerenes by halogenation has not been previously reported and remains a challenging endeavor in carbon nanoscience. In this work, we show that halogenation of endohedral metallofullerenes is predicted to be feasible based on thermodynamic grounds by means of DFT computations, combined with in situ experimental investigations. Computed bond energies for the chlorination, fluorination and hydrogenation of endohedral metallofullerenes that span a range of cage sizes are found to be comparable to those of known halogenated and hydrogenated empty fullerenes. Therefore, we propose that new forms of functionalized metallofullerenes should be synthesized under appropriate experimental conditions, despite many prior unsuccessful attempts. Indeed, we experimentally show for the first time that M@C2n (M = metal) metallofullerenes and the prototypical Sc3N@C80 clusterfullerene can be fluorinated by two different routes under the typical ‘harsh’ gas phase conditions of metallofullerene plasma synthesis, and at lower extents that could avoid cage degradation. The combination of halogenation and metal encapsulation offers the potential to create new radical-quenched, functionalized endohedral metallofullerenes that possess stable, large-gap carbon cages. These results open new avenues for the synthesis and stabilization of encapsulated molecular nanocarbons.

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 C72(11188) with C2v symmetry, which is topologically linked to the only IPR isomer of C70, 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 C2v-C72(11188) is found to take four chlorines, whereas cage C1-C74(14049) is observed to capture 10 of them, eve...

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.

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

Fullerenes that encapsulate clusters of atoms represent a fundamental interest in chemistry, materials, and carbon science due to their unique properties and nanoscale structures. Numerous cages that feature a combination of carbon, metal, and heteroatom-based clusters have been discovered since, for example, Sc3NC@C80 was first reported. Nanocarbon reactions that underlie formation of such compounds, however, are not well understood. Here, we experimentally investigate intramolecular reactions of metallofullerenes in the gas phase by means of laser-based techniques, analyzed by high magnetic field Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. A variety of structurally defined clusterfullerene cages (e.g., Sc3N@C68, Sc3N@C78, etc.) are probed under energetic conditions to decipher reactions that may lead to encapsulation of C atoms, as well as clusterfullerenes that include metal-loss products. An aim of the present work is to identify mechanistic processes and principles that guide formation of metallofullerenes that entrap carbon, metal, and heteroatom-based clusters.

We have observed new mechanistic insight into the formation of metallic nitride clusterfullerenes from doped graphite by use of laser-based plasma synthesis techniques, analyzed by ultrahigh resolution 9.4 tesla Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. These online chemical sampling techniques provide a route to investigate underexplored nanocarbon reactions that take place under the harsh conditions of metallofullerene synthesis, and are expected to be applicable to macroscopic production methods. Here, we report efforts to form various clusterfullerenes by laser vaporization and extend these techniques as new avenues for investigation of exohedral functionalization (e.g., fluorination of Sc3N@C80) and heteroatom-doping of endohedral fullerenes. This work was supported by NSF Division of Materials Research through DMR-11-57490 and the State of Florida.