Kinetics of the Diels-Alder reaction between C60 and acenes

The kinetics of the Diels-Alder reactions between C-60 and the linear acenes anthracene and tetracene are studied in toluene, in the temperature range 22-63 degreesC. It is observed that tetracene reacts much more readily with C-60 than does anthracene. The different reactivities of anthracene and tetracene towards C-60 correlate with the respective aromaticity loss upon cycloaddition, as previously predicted theoretically. The two monoadducts also display different kinetics as regards the dissociation back to the reagents. In the studied temperature range, tetracene monoadduct decomposition by retro-Diels Alder reaction is negligible, while the anthracene monoadduct is unstable above room temperature. (C) 2004 Elsevier B.V. All rights reserved.