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Addition of silyl and germylmethyl azides ( 1 ) to fullerene C 60 at 50 °C through [2+3] cycloaddition led to the formation of the triazoline adducts ( 2 ). Subsequently, heating 2 at 100 °C in the solid state, caused N 2 extrusion producing two different isomers, [5,6]-azafulleroid ( 3 ) and [6,6]-aziridinofullerene ( 4 ). The 13 C NMR spectrum of 3 had an absence of resonances in the aliphatic region for the fullerene C 60 cage, showing a fulleroid with C S symmetry. In contrast, 4 exhibited one sp 3 resonance in the aliphatic region for the fullerene C 60 cage, indicative of an aziridinofullerene with C 2V symmetry. However, MALDI-TOF mass characterization was hampered because ion peaks corresponding to the bis-adduct are detected in positive ion mode measurements, whereas the ion peaks [M−N 2 ] − for 2a as well as [M] − for 3a and 4a are observed in negative ion measurements. In an effort to obtain X-ray data, silyl and germylphenyl groups were introduced to form intermolecular complexes with fullerene C 60 . The X-ray structures of 3c and 3d revealed a strong enhancement of homoconjugation in the bridged annulene moiety based on POAV analysis. The X-ray structures of 3c , d and 4c were confirmed with the detection of silyl and germylphenyl-C 60 interactions, similar to dimethoxyphenyl-C 60 interactions. |
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