Evaluation of an Intramolecular Approach for the Synthesis of the Elusive C58N2 Heterofullerene Family

A new approach towards the synthesis of the elusive heterofullerene C58N2 is presented. The synthetic strategy is based on the intramolecular 1,3‐dipolar cycloaddition of a spacer‐linked azide to a monoazaheterofullerene (C59N) core. Since this cycloaddition can theoretically result in 16 different isomeric products, the design of the spacer moiety was based on extensive molecular modelling. Two fundamental synthetic routes towards suitably functionalized C59N derivatives were designed and carried out. Subsequent one‐pot experiments, each making use of the same conditions as had previously been employed for the introduction of the first nitrogen atom into the fullerene framework, were performed. Immediate analysis by FAB mass spectrometry indicated that up to 20 % of the submitted material indeed gave C58N2 species as fragmentation products. This result not only represents the first strategic synthesis of a C58N2 derivative, but also holds great promise for further efforts directed towards the preparative isolation of a member of the diaza[60]fullerene family. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)