Oxidation of azafulleroids with peracids regenerated C60 depending on the N-substituents. Alkyl-substituted azafulleroids preferred the oxidation of nitrogen to afford N-oxides as possible intermediates for C60 in moderate yields. Phenyl- and tosyl-substituted azafulleroids rather allowed the oxidation at the carbon cage. Theoretical calculations predicted the order of reactivity of azafulleroids as well as the relative N/C nucleophilicity.
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http://dx.doi.org/10.1039/c5ob00272a | DOI Listing |
Angew Chem Int Ed Engl
November 2023
Hefei National Research Center for Physical Sciences at the Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.
Herein, we report divergent additions of 2,2'-diazidobiphenyls to C and Sc N@I -C . In stark contrast to that of the previously reported bis-azide additions, the unexpected cascade reaction leads to the dearomative formation of azafulleroids 2 fused with a 7-6-5-membered ring system in the case of C . In contrast, the corresponding reaction with Sc N@I -C switches to the C-H insertion pathway, thereby resulting in multiple isomers, including a carbazole-derived [6,6]-azametallofulleroid 3 and a [5,6]-azametallofulleroid 4 and an unusual 1,2,3,6-tetrahydropyrrolo[3,2-c]carbazole-derived metallofullerene 5, whose molecular structures have been unambiguously determined by single-crystal X-ray diffraction analyses.
View Article and Find Full Text PDFChempluschem
December 2018
Institute for Chemical Research, Kyoto University Uji, Kyoto, 611-0011, Japan.
We have studied the efficiency of the C=C double bond cleavage on open-cage fullerene C derivatives by singlet oxygen using four different LED lamps including UV, blue, green, and red radiation. The results indicate that red radiation is the most efficient for this photochemical oxidation owing to the sufficient penetration of the longer-wavelength light. By applying this method to a 2-methoxyethoxymethyl-substituted azafulleroid derivative, we demonstrated the sequential double photooxygenation which provides a symmetric diketo imide derivative having a 15-membered-ring opening via stepwise cleavage of two C=C double bonds.
View Article and Find Full Text PDFSci Rep
June 2018
Deparment of Materials and Thomas Young Centre, Imperial College London, London, SW7 2AZ, UK.
A donor-acceptor system, 4-thiophenyl-azafulleroid (4TPA-C), is investigated at the point of HOMO/LUMO resonance and beyond to understand how negative differential resistance (NDR) features may be observed in such systems. Our previous investigation showed that charge transfer between the occupied and unoccupied states at resonance hindered crossing of the HOMO and LUMO levels, thus preventing the formation of an NDR feature. In this work, it is shown that the negative differential resistance feature of 4TPA-C can be tailored based on the couplings at the metal/molecule interface.
View Article and Find Full Text PDFOrg Lett
December 2016
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
The removal of addends on the fullerene C cage plays an important role in the final stage for synthesizing endohedral fullerenes by the molecular surgery method. We developed a cobalt-mediated reaction to regenerate C from N-substituted C derivatives (aziridinofullerene and azafulleroid). In these reactions, we found the formation of a green monovalent-cobalt complex of C, and its structure was unambiguously determined by X-ray analysis.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2016
State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, P.R. China.
Labile bis-triazoline adducts of C60 are supposed to be the precursors of bis-azafulleroids, but the formation mechanism is still unclear because of the incomplete isolation of the thermolized products and the lack of X-ray structures. A rigid-tethered reagent 1,2-bis(azidomethyl)benzene (1) was used to regioselectively synthesize the labile 1,2,3,4-bis(triazolino)[60]-fullerene (2), the structure of which was determined by single-crystal X-ray crystallography. Further thermolysis of 2 produces four products (3 a-3 d), which were all characterized by X-ray crystallography.
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