Reversible Diels-Alder Addition to Fullerenes: A Study of Dimethylanthracene with H-2@C-60

The study of isolated atoms or molecules inside a fullerene cavity provides a unique environment. It is likely to control the outer carbon cage and study the isolated species when molecules or atoms are trapped inside a fullerene. We report the Diels-Alder addition reaction of 9,10-dimethyl anthracene (DMA) to H-2@C-60 while H-1 NMR spectroscopy is utilized to characterize the Diels-Alder reaction of the DMA with the fullerene. Through H-1 NMR spectroscopy, a series of isomeric adducts are identified. The obtained peaks are sharp, precise, and straightforward. Moreover, in this paper, H-2@C-60 and its isomers are described for the first time.