115383-22-7Relevant articles and documents
Structure and properties of the Fullerene Dimer C140 produced by pressure treatment of C70
Lebedkin, Sergei,Hull, William E.,Soldatov, Alexander,Renker, Burkhard,Kappes, Manfred M.
, p. 4101 - 4110 (2000)
A [2+2] cycloaddition cap-to-cap C70 dimer with C2h, molecular symmetry was synthesized in high yield by pressure treatment of polycrystalline C70 at 1 GPa and 200 °C. It was separated from unreacted monomers by chromatography and characterized by 13C NMR, Raman, and infrared spectroscopy, and other methods. Remarkably, only one isomer was produced out of the five possible [2+2] cycloaddition products which have equally low formation energies according to semiempirical modeling calculations. The dimer obtained is the one favored when C70 molecules adopt an ordered packing with parallel D5 axes. The intercage bonding in C140, its thermal stability, and intercage vibrational modes are similar to those found for the C60 dimer, C120. Both dimers photodissociate to the monomers in solution, probably via excited triplet states. The UV absorption and fluorescence properties of C140 are not very different from those of C70, suggesting only weak electronic interactions between the two cages of C140. In comparison, the pressure-induced dimerization of C60, under the conditions used for C70, results mainly in C60 oligomers and polymeric chains, but the dimer C120 could be isolated at low yield when short reaction times (≤5 min) were used.
The chemical retro-Bingel reaction: Selective removal of bis(alkoxycarbonyl)methano addends from C60 and C70 with amalgamated magnesium
Moonen, Nicolle N. P.,Thilgen, Carlo,Echegoyen, Luis,Diederich, Francois
, p. 335 - 336 (2000)
Bis(alkoxycarbonyl)methano addends are removed from C60 and C70 derivatives by reaction with amalgamated magnesium in dry THF; this facile and selective retro-Bingel reaction, which leaves pyrrolidine rings fused to C60 intact, opens up the possibility of using bis(alkoxycarbonyl)methano addends as protecting and reversible directing groups in the regioselective multiple functionalization of fullerenes.
Unimolecular dissociations of C70+ and its noble gas endohedral cations Ne@C70+ and Ar@C70 +: Cage-binding energies for C2 loss
Cao, Baopeng,Peres, Tikva,Cross, R. James,Saunders, Martin,Lifshitz, Chava
, p. 10257 - 10263 (2005)
The energetics and dynamics of unimolecular decompositions of C 70+ and its noble gas endohedral cations, Ne@C 70+ and Ar@C70+, have been studied using tandem mass spectrometry techniques. The high-resolution mass-analyzed ion kinetic energy (HR-MIKE) spectra for the unimolecular reactions of C 70+, Ne@C70+, and Ar@C 70+ were recorded by scanning the electrostatic analyzer and using single-ion counting that was achieved by combination of an electron multiplier, amplifier/discriminator, and multichannel analyzer. These cations dissociate unimolecularly via loss of a C2 unit, and no endohedral atom is observed as fragment. The activation energies for C2 evaporation from Ne@C70+ and Ar@C70+ are lower than those for elimination of the endohedral noble gas atoms. The kinetic energy release distributions (KERDs) for the C2 evaporation have been measured and, by use of the finite heat bath theory (FHBT), the binding energies for the C2 emission have been deduced from the KERDs. The C2 evaporation energies increase in the order ΔEvap(C70+) vap(Ne@C70+) vap(Ar@C70+), but no big difference in the cage binding was observed for C70+, Ne@C70 +, and Ar@C70+, indicating incorporations of the Ne and Ar atoms into C70 contribute a little to the stability of C70 toward C2 loss, which is in good agreement with theoretical calculations but contrasts with the findings in their C60 analogues and in metallofullerenes that the decay energies of the filled fullerenes are much higher than those of the corresponding empty cages.
Self-crystallization of C70 cubes and remarkable enhancement of photoluminescence
Park, Chibeom,Yoon, Eunjin,Kawano, Masaki,Joo, Taiha,Choi, Hee Cheul
, p. 9670 - 9675 (2010)
Good solvent, poor solvent: A simple precipitation method enabled the spontaneous formation of homogeneous C70 cube crystals by self-crystallization in cavities of a good solvent (mesitylene) surrounded by a poor solvent (isopropyl alcohol, IPA; see picture). The enormously increased photoluminescence (PL) intensity of the C70 cube crystals relative to that of C70 powder was mainly attributed to the high crystallinity of the cubes. Copyright
Synthesis and properties of fullerene (C70) complexes of 2,6-bis(porphyrin)-substituted pyrazine derivatives bound to a Pd(II) ion
Eda, Yusaku,Itoh, Kennosuke,Ito, Yoshio N.,Fujitsuka, Mamoru,Majima, Tetsuro,Kawato, Toshio
, p. 517 - 523 (2010)
2,6-Bis(porphyrin)-substituted 3,5-dimethylpyrazine and its zinc complex bound C70 to yield 1:1 inclusion complexes, which were characterised by ESI-MS, UV-vis, fluorescence and NMR spectroscopies. Association constants of the C70 complexes were determined by fluorescence and NMR spectral analyses. A decrease in absorbance of the Soret band of the pyrazine derivative by the effect of C70 was observed, suggesting the existence of a charge transfer interaction between C70 and porphyrin. Experimentally reliable values for the association constants were obtained by the NMR method and were about six times larger than those of the corresponding C60 complexes. Palladium complexation of the porphyrin-pyrazine ligand was found to enhance the association with fullerene. The association constant of 2,6-bis(porphyrin-Zn)- substituted 3,5-dimethylpyrazine-Pd(II) complex with C70 was determined to be 8400±900M-1. From the comparison of the association constants, it was found that inclusion room for C70 in the Pd(II) complex was maintained, juxtaposed between porphyrins attached to the opposite sides of the pyrazine ligands.
Synthesis of [70]azafulleroids: Investigations of azide addition to C70
Bellavia-Lund, Cheryl,Wudl, Fred
, p. 943 - 946 (1997)
Treatment of C70 with (2-methoxyethoxy)methyl azide gives rise to three out of a possible six triazoline isomers, showing chemoselectivity as well as regioselectivity. The major product arose from addition of azide to the double bond of C70 possessing the greatest local curvature. Selective thermolysis of the least stable triazoline, the one resulting from addition to the least curved [6,6] double bond, allowed solution of the structure of the three isomers. Thermolysis of the triazoline isomers produced mixtures of C70, azafulleroids, and fulleroaziridines.
CF2-Bridged C60 Fullerene Dimers and their Optical Transitions
Dallas, Panagiotis,Zhou, Shen,Cornes, Stuart,Niwa, Hiroyuki,Nakanishi, Yusuke,Kino, Yasuhiro,Puchtler, Tim,Taylor, Robert A.,Briggs, G. Andrew. D.,Shinohara, Hisanori,Porfyrakis, Kyriakos
, p. 3540 - 3543 (2017/11/22)
Fullerene dyads bridged with perfluorinated linking groups have been synthesized through a modified arc-discharge procedure. The addition of Teflon inside an arc-discharge reactor leads to the formation of dyads, consisting of two C60 fullerenes bridged by CF2 groups. The incorporation of bridging groups containing electronegative atoms lead to different energy levels and to new features in the photoluminescence spectrum. A suppression of the singlet oxygen photosensitization indicated that the radiative decay from singlet-to-singlet state is favoured against the intersystem crossing singlet-to-triplet transition.
Unusual multistep reaction of C70Cl10 with thiols producing C70[SR]5H
Khakina, Ekaterina A.,Peregudov, Alexander S.,Yurkova, Anastasiya A.,Piven, Natalya P.,Shestakov, Alexander F.,Troshin, Pavel A.
, p. 1215 - 1219 (2016/03/01)
We report a reaction of the chlorofullerene C70Cl10 with thiols producing C70[SR]5H with all organic addends attached around one central pentagon at the pole of the C70 cage. This reaction was shown to proceed via a complicated radical pathway, presumably involving addition, substitution, rearrangement, and/or elimination steps. The obtained C70[SR]5H products were shown to be very unstable and undergo quantitative decomposition to pristine C70, RSSR, and RSH at elevated temperatures (e.g., 50 °C). Quantum chemical calculations and NMR spectroscopy data showed that cleavage of organic addends from the fullerene cage could be induced by solvation effects in solution.