Kinetic Substituent and Solvent Effects in 1,3-Dipolar Cycloaddition of Diphenyldiazomethanes with Fullerenes C<sub>60</sub> and C<sub>70</sub>: A Comparison with the Addition to TCNE, DDQ, and Chloranil
Kinetics of 1,3-dipolarcycloaddition of a series of meta- and para-substituted diphenyldiazomethanes (DDMs) with fullerenes C60 and C70 as dipolarophiles have been investigated in toluene at 30 °C. Fullerene C60 was ca. 1.5 times more reactive than C70. The rate constants (k) for the primary [3 + 2] additions increased with the increase of the electron-releasing ability of the meta and para substituent
Observation of Both Thermal First-Order and Photochemical Zero-Order Kinetics in the Rearrangement of [6,5] Open Fulleroids to [6,6] Closed Fullerenes
作者:Melvin H. Hall、Huajun Lu、Philip B. Shevlin
DOI:10.1021/ja003042w
日期:2001.2.1
A series of [6,5] open fulleroids with radical stabilizing groups on the methano bridge were synthesized and their rearrangements to the more stable [6,6] closed fullerenes studied. These [6,5] open fulleroids all rearrange both by a zero-order photochemical process and by a higher energy unimolecular pathway involving disrotatory closure to the [6,5] closed fullerene, which subsequently rearranges
Electron-Acceptor-Induced Isomerization of Aryl [6,5] Open Fulleroids to [6,6] Closed Methanofullerenes and the Electrochemical Evaluation of Their Free Energy Difference
作者:Melvin H. Hall、Philip Shevlin、Huajun Lu、Anthony Gichuhi、Curtis Shannon
DOI:10.1021/jo0521706
日期:2006.4.1
aryl substituted [6,5] open fulleroids to [6,6] closed methanofullerenes are accelerated in the presence in of electron acceptors. These [6,5] open fulleroids, facilitated by electron acceptors, rearrange thermally by a zwitteronic-type intermediate, while the photochemical reactions proceed via an excited-state electron-transfer process. The oxidation potentials of these [6,5] open fulleroids and their
In the title compound, C75H14O2, a bis(4-methoxyphenyl)methylene group bridges a 6-6-ring junction of the C-60 sphere, forming a slightly deformed cyclopropane ring. The C-C bond length involved in the cyclopropane ring fusion is 1.635 (4) Angstrom, more than 0.2 Angstrom longer than that at the 6-6-ring junction of C-60. The elongation of this C-C bond leads to a slight deformation of the C-60 framework, especially a shortening of two C-C bonds in equatorial positions.
Selective Electrolytic Removal of Bis(alkoxycarbonyl)methano Addends from C60 Bis-adducts and Electrochemical Stability of C70 Derivatives
作者:Roland Kessinger、Nicolette S. Fender、Lourdes E. Echegoyen、Carlo Thilgen、Luis Echegoyen、François Diederich
group in the construction of multiple adducts of C60 with unusual addition patterns. The Bingel-type mono-adduct of C70 10 and the constitutionally isomeric bis-adducts 11, (+/-)-12, and (+/-)-13 were also included in this investigation. A large difference in the electrochemical behavior between C70 bis-adducts and the corresponding C60derivatives was observed. Thus, the intramolecular "walk-on-the-sphere"