10.1016/j.tet.2012.04.061
The research presents a novel synthetic method for creating linear, diastereomerically pure fullerene triads, which are compounds consisting of two fullerene cages linked by an organic spacer. The purpose of this study is to develop a versatile and efficient route for synthesizing these triads, which have potential applications in molecular electronics, artificial photosynthetic systems, and supramolecular chemistry. The key chemicals used include fullerene C60 and C70, N,N'-dicyclohexylcarbodiimide (DCC) for activation, and various dicarboxylic acids and fulleropyrrolidines as precursors. The method involves functionalizing fullerene cages via a Prato reaction to form pyrrolidine rings, followed by a DCC-activated amidation reaction to link the fullerene cages. The study concludes that the yield of the coupling reaction is maximized in o-dichlorobenzene at high concentrations of the reactant fullerene nucleophile, while more polar solvents or lower concentrations favor the formation of unwanted side-products. The resultant triads exhibit good solubility in common organic solvents, enabling detailed characterization by NMR, IR, UV-vis spectroscopy, and MALDI-TOF mass spectrometry. This method allows for the flexible introduction of different fullerene cages and spacers, providing a wide range of symmetric and asymmetric fullerene structures without forming diastereomeric mixtures.