AN AM1 STUDY OF THE REACTIVITY OF BUCKMINSTERFULLERENE (C-60) IN A DIELS-ALDER MODEL REACTION

The formation of a 'ball-and-chain' model adduct through a Diels-Alder reaction between 2,3-dimethylidene-bicyclo [2.2.2] octane (C10H14) an d buckminsterfullerene (C-60) has been studied theoretically by means of the AM1 semi-empirical method. The different reactivity of the 6-6 and 6-5 ring junctions in C-60 is explained by taking into account the different deformation enthalpies of the 6-6 and 6-5 bonds in the resp ective transition states. The experimental fact involving formation of only the 6-6 product is correctly reproduced by the energy barriers c alculated for the 6-6 and 6-5 ring junction attacks.