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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%).

In this work, two new C(70) isomers, α and β bis(2-(thiophen-2-yl)ethyl)-C(70)-fullerene mono-adducts (DTC(70)), 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 J(sc) and FF values of the devices, when compared to the results for the β-isomer and to those for phenyl-C(70)-butyric acid methyl ester (PC(71)BM), used as control. Devices based on α-DTC(70) achieved a power conversion efficiency (PCE) of 15.9%, which is higher than that observed with PC(71)BM (15.1%).

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

Since the discovery of buckminsterfullerene in 1985,1 intensive research has been devoted to this family of closed-cage carbon nanostructures. Endohedral metallofullerene La@C60 was already detected the same year and La@C82 was isolated few years later.2 In 1999, the synthesis, isolation and characterization of the first clusterfullerene Sc3N@C80 using the Krätschmer-Huffman method was a milestone in the field of endohedral metallofullerenes (EMF).3 The characteristic structural and electronic properties of EMFs, as well as their reactivity, have been extensively analyzed by experimental and theoretical groups.4 In particular, different rules to predict the relative stability of fullerene cages, based on the ionic model, were proposed.5 A different way to modify the properties of fullerenes is by replacing a carbon atom in the caged network with a heteroatom. The resulting heterofullerene shows distinct electronic structure and, therefore, properties from the all-carbon cage precursor. Nitrogen-doped heterofullerenes have received much more attention and investigation than boron-doped heterocages.6 Few years ago, Dunk et al. reported facile gas-phase formation of C59B by atom exchange resulting from exposure of C60 to boron vapor by means of a pulsed laser vaporization cluster source, which was the first report of borafullerene formation directly from pristine C60.7 Recent application of this technique to endohedral monometallofullerenes and clusterfullerenes at the National High Magnetic Field Laboratory in Florida lead to the formation of boron-doped EMFs with exciting electronic properties. We here analyze the characteristic electronic structure of observed B-doped metalloheterofullerenes, rationalize their stabilities and discuss about their properties. References Kroto, H. W.; Heath, J. R.; O’Brien, S. C.; Curl, R. F.; Smalley, R. E. Nature 1985, 318, 162-163. a) Heath, J. R.; O’Brien, S. C.; Zhang, Q.; Liu, Y.; Curl, R. F.; Kroto, H. W.;Tittel, F. K.; Smalley, R. E. J. Am. Chem. Soc. 1985, 107, 7779-7780; (b) 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. 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. a) Rodríguez-Fortea, A.; Balch, A. L.; Poblet, J. M. Chem. Soc. Rev. 2011, 40, 3551-3563; b) Popov, A. A.; Yang, S.; Dunsch, L. Chem. Rev. 2013, 113, 5989-6113. a) Rodríguez-Fortea, A.; Alegret, N.; Balch, A. L.; Poblet, J. M., Nature Chem. 2010, 2, 955-961; b) Garcia-Borràs M., Osuna S., Swart M., Luis J.M., Solà M. Angew. Chem. Int.. Ed. 2013, 52, 9275-9278; c) Wang, Y.; Díaz-Tendero, S.; Martín, F. and Alcamí, M. J. Am. Chem. Soc., 2016, 138, 1551-1560. Lamparth, I.; Nuber, B.; Schick, G.; Skiebe, A.; Grosser, T.; Hirsch, A. Angew. Chem. Int. Ed. Engl. 1995, 34, 2257. Dunk, P. W.; Rodríguez-Fortea, A.; Kaiser, N. K.; Shinohara, H.; Poblet, J. M.; Kroto, H. W. Angew. Chem. Int. Ed. 2013, 52, 315-319.

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.

Computational chemistry has helped so far not only to understand the regioselectivity of a wide variety of chemical functionalizations on C60 and endohedral metallofullerenes (EMFs), but also to disclose in many cases their reaction mechanisms. In this communication we will show the recent progress on our group related to different topics, as (1) the prediction of halogenation and hydrogenation of EMFs confirmed by experiments; and (2) the analysis of stereoselective reactions on C60 hexaadducts, as well as other related systems.