Fullerene skeleton modification has been investigated through selective cleavage of the fullerene carbon-carbon bonds under mild conditions. Several cage-opened fullerene derivatives including three [59]fullerenones with an 18-membered-ring orifice and one [59]fullerenone with a 19-membered-ring orifice have been prepared starting from the fullerene mixed peroxide 1, C60(OOtBu)6. The prepositioned tert-butyl peroxy groups in 1 serve as excellent oxygen sources for formation of hydroxyl and carbonyl groups. The cage-opening reactions were initiated by photoinduced homolysis of the tBu-O bond, followed by sequential ring expansion steps. A key step of the ring expansion reactions is the oxidation of adjacent fullerene hydroxyl and amino groups by diacetoxyliodobenzene (DIB). Aminolysis of a cage-opened fullerene derivative containing an anhydride moiety resulted in multiple bond cleavage in one step. A domino mechanism was proposed for this reaction. Decarboxylation led to elimination of one carbon atom from the C60 cage and formation of [59]fullerenones. The cage-opened [59]fullerenones were found to encapsulate water under mild conditions. All compounds were characterized by spectroscopic data. Single-crystal structures were also obtained for five skeleton-modified derivatives including two water-encapsulated fulleroids.

Thermolysis of the fullerene hexaadduct C(60)(OO(t)Bu)(6) results in cleavage of two O-O bonds and elimination of two tert-butoxy groups to form two isomeric products with the formula C(60)(O)(2)(OO(t)Bu)(4) in comparable yields. The two oxygen atoms exist as two epoxy groups in one isomer 3, and as an epoxy and an ether group in the other isomer 2. Addition of hydroxylamine to 2 opens both the epoxy and the ether moieties to give a cage-opened keto-ketoxime derivative.

Norfullerenes are fullerene-like compounds (fulleroids) resulting from partial deletion of fullerene skeleton carbons. The one carbon less norfullerene C59(O) 3 derivatives having three carbonyl groups on the rim of the orifice are prepared through peroxide-mediated reactions. A key step involves a novel PCl 5 initiated rearrangement of a hydroxyl amine adduct. Decarboxylation serves as the carbon removal step.

The isolated cyclopentadiene moiety in a fullerene multi-adduct derivative reacts readily with dienophiles to form [4 + 2] cycloaddition products.

Repeated acid catalyzed epoxide opening and oxidation of the resulting diol with diacetoxyiodobenzene led to two 10-membered orifices on C(60) cage.

Equilibrium deuterium isotope effects for exchange of hydroxyl deuterons and protons among tert-butanol, phenol, ethanethiol, diethylamine, and ethanol were measured by using NMR and also calculated theoretically. Deuterated ethanol could be used as a probe for measuring equilibrium isotope effects (EIE) for hydroxyl exchange; tert-butanol, phenol, ethanethiol, diethylamine, and pyrrole were used as five representive examples. A procedure called the "one-atom isotope effect" was used to save time in the calculations.

Fullerene derivatives Q 1145 Switched Role of Fullerene in the Diels-Alder Reaction: Facile Addition of Dienophiles to the Conjugated Fullerene Diene Moiety. -(YAO, J.; XIAO, Z.; ZHANG, J.; YANG, X.; GAN, L.; ZHANG*, W.-X.; Chem. Commun. (Cambridge) 2009, 4, 401-403; Coll. Chem. Mol. Eng., Peking Univ., Beijing 100871, Peop. Rep. China; Eng.) -M. Paetzel 24-088

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