We present a review of the methods most frequently used for the synthesis of fullerenes and the changes that these methods have experienced since 1985 when Kroto and co-workers discovered C 60 . We also analyze the most important models that explain the mechanism of the formation of fullerenes in carbon soot, as well as the new methodologies that lead to the rational chemical synthesis of fullerenes and of fullerene fragments as precursors.

Density Functional Theory has been used to model the Diels-Alder reactions of the fullerene fragments triindenetriphenilene and pentacyclopentacorannulene with ethylene and 1,3-butadiene. The purpose is to prove the feasibility of using Diels-Alder cycloaddition reactions to grow fullerene fragments step by step, and to dimerize fullerene fragments, as a way to obtain C60. The dienophile character of the fullerene fragments is dominant, and the reaction of butadiene with pentacyclopentacorannulene is favored.

Abstract:The Diels-Alder (DA) reaction provides an attractive route to increase the number of six member rings in substituted Polycyclic Aromatic Hydrocarbons (PAHs). The density functional theory (DFT) B3LYP method has been used in this work to inquire if the substitution of H over the edge of triindenetriphenylene (pristine hemifullerene 1) and pentacyclopentacorannulene (pristine hemifullerene 2), could improve the DA cycloaddition reaction with 1,3-butadiene. The substituents tested include electron-donating (NH2, OMe, OH, Me, i-Pr) and electron-withdrawing groups (F, COOH, CF3, CHO, CN, NO2). The electronic, kinetic and thermodynamic parameters of the DA reactions of the substituted hemifullerenes with 1,3-butadiene have been analyzed. The most promising results were obtained for the NO2 substituent; the activation energy barriers for reactions using this substituent were lower than the barriers for the pristine hemifullerenes. This leads us to expect that the cycloadditions to a starting fullerene fragment will be possible.

De 28 muestrasm de suelo provenientes de cultivos de papa, se aislaron 69 colonias de bacterias diferentes en Caldo Nutritivo con Mancozeb (0,0625mg/ml). Las cepas aisladas, se cultivaron por 24h a 25 grados centigrados en caldo Sales, suplementado con fuentes de carbono (glucosa 0,1%), nitrógeno (nitrato de potasio 0,2%) o sin ellos y mancozeb (Dithane M45 NT) a concentraciones de 0.062mg/ml, seleccionado 3 cepas promisorias, las cuales fueron cultivadasen caldo SGNM por 72h. La cepa de P. putida presento el mejor comportamiento en este medio de cultivo hasta la 72h, indicando posible uso del mancozeb como fuente adicional de cabono. a actividad biológica de la cepa Pseudomonas putida sobre el mancozeb, se determinó utilizando una cepa de bacillus cereus sensible al mancozeb como indicador de concentaciones resiudales de mancozeb en los medios de digestión; se detectó que en 24 horas la cepa de P. putida con una población inicial de 10 cédulas/ml, degradó el mancozeb con una población de P. putida baja, la presenta como promisoria para usos en biorremdiación de usos.

The development of new techniques for the synthesis of fullerenes is needed to reduce the production cost and the availability of those materials.[1-10] In this work we study, using the density functional theory (DFT) and the nudge elastic band (NEB) method, a route to obtain the C60 from two pentacyclopentacorannulene C30H10 fragments. The accessible precursor of C60, is a C60H20 molecule, which is a C60 fullerene wrapped by a double belt of twenty H atoms forming C-H bonds around the equatorial plane of C60 (the poles are occupied by the central pentagons of the two fragments). The proposed C60H20 molecule has a synthetic analogue reported by Boltalina et al.[11] Our theoretical justification for the dimerization of the C30H10 fragments supports the achievable synthetic route for the C60.[12] References. 1.- Diederich, Y. Rubin, Angew. Chem. Int. Ed., 1992, 31, 1101. 2.- T. Scott, Angew. Chem. Int. Ed., 2004, 43, 4994. 3.- M. Tsefrikas, L. T. Scott, Chem. Rev., 2006, 106, 4868. 4.- Mojica, F., J. A. Alonso, J. Phys. Org. Chem., 2013, 26, 526. 5.- T. Scott, M. M. Boorum, B. J. McMahon, S. Hagen, J. Mack, J. Blank, H. Wegner, A. de Meijere, Science, 2002, 295, 1500. 6.- Otero, G. Biddau, C. Sánchez-Sánchez, R. Caillard, M. F. López, C. Rogero, F. J. Palomares, N. Cabello, M. A. Basanta, J. Ortega, J. Méndez, A. M. Echavarren, R. Pérez, B. Gómez-Lor, J. A. Martín-Gago, Nature, 2008, 454, 865. 7.- B. M. Ansems, L. T. Scott, J. Am. Chem. Soc., 2000, 122, 2719. 8.- H. F. Bunz, Y. Rubin, Y. Tobe, Chem. Soc. Rev., 1999, 28,107. 9.- L. Chapman, M. R. Engel, J. P. Springer, J. C. Clardy, J. Am. Chem. Soc., 1971, 93, 6696 10.- T. Scott, M. A. Petrukhina, Preface in Fragments of Fullerenes and Carbon Nanotubes: Designed Synthesis, Unusual Reactions and Coordination Chemistry; L. T. Scott, M. A. Petrukhina, Eds.; John Wiley & Sons Inc., Hoboken, New Jersey, 2012, pp. vii–x. 11.- V. Boltalina, V. Yu. Markov, P. A. Troshin, A. D. Darwish, J. M. Street, and R. Taylor, Angew. Chem. Int. Ed., 2001, 40, 787. 12.- A. Richaud, M. J. López, M. Mojica, J. A. Alonso, F. Méndez. RSC Adv., 2020, 10, 3689-3693. https://doi.org/10.1039/C9RA09804F.

The chemical synthesis of fullerenes is still a challenge.[1-4] The development of new techniques is needed to reduce the production cost and the availability of those materials.[5-10] In this work we study, using the density functional theory (DFT) and the nudge elastic band (NEB) method, a route to obtain the C60 from two pentacyclopentacorannulene C30H10 fragments. The accessible precursor of C60, is a C60H20 molecule, which is a C60 fullerene wrapped by a double belt of twenty H atoms forming C-H bonds around the equatorial plane of C60 (the poles are occupied by the central pentagons of the two fragments). The proposed C60H20 molecule has a synthetic analogue reported by Boltalina et al.[11] Our theoretical justification for the dimerization of the C30H10 fragments supports the achievable synthetic route for the C60. References. 1.- Diederich, Y. Rubin, Angew. Chem. Int. Ed., 1992, 31, 1101. 2.- T. Scott, Angew. Chem. Int. Ed., 2004, 43, 4994. 3.- M. Tsefrikas, L. T. Scott, Chem. Rev., 2006, 106, 4868. 4.- Mojica, F., J. A. Alonso, J. Phys. Org. Chem., 2013, 26, 526. 5.- T. Scott, M. M. Boorum, B. J. McMahon, S. Hagen, J. Mack, J. Blank, H. Wegner, A. de Meijere, Science, 2002, 295, 1500. 6.- Otero, G. Biddau, C. Sánchez-Sánchez, R. Caillard, M. F. López, C. Rogero, F. J. Palomares, N. Cabello, M. A. Basanta, J. Ortega, J. Méndez, A. M. Echavarren, R. Pérez, B. Gómez-Lor, J. A. Martín-Gago, Nature, 2008, 454, 865. 7.- B. M. Ansems, L. T. Scott, J. Am. Chem. Soc., 2000, 122, 2719. 8.- H. F. Bunz, Y. Rubin, Y. Tobe, Chem. Soc. Rev., 1999, 28,107. 9.- L. Chapman, M. R. Engel, J. P. Springer, J. C. Clardy, J. Am. Chem. Soc., 1971, 93, 6696 10.- T. Scott, M. A. Petrukhina, Preface in Fragments of Fullerenes and Carbon Nanotubes: Designed Synthesis, Unusual Reactions and Coordination Chemistry; L. T. Scott, M. A. Petrukhina, Eds.; John Wiley & Sons Inc., Hoboken, New Jersey, 2012, pp. vii–x. 11.- V. Boltalina, V. Yu. Markov, P. A. Troshin, A. D. Darwish, J. M. Street, and R. Taylor, Angew. Chem. Int. Ed., 2001, 40, 787.

The chemical synthesis of C60 fullerene in the laboratory is still a challenge.

A two-step synthesis of the novel 5,8-dimethyl-7,8-dihydro-5,8-ethanoindolizine-6,9(5H)-dione from 2,3-dimethyl-1,4-benzoquinone is described. The key step of the synthesis of this unusual fused tricyclic system is the intramolecular regiospecific aza-Michael addition of a pyrrole to an activated double bond by reaction with tetrabutylammonium fluoride under mechanochemical conditions.