REACTIONS OF C-60 AND C-70 WITH CYCLOPENTADIENE

The kinetics of addition of cyclopentadiene to fullerene C60 and fullerene C70 have been studied in the temperature range 291-354 K by high-pressure liquid chromatography. The rate of addition of cyclopentadiene to fullerene C60 is about 7 times as fast as the rate of addition to fullerene C70 at 293 K. The activation energies for the two reactions are 29 and 67 kJ mol-1, respectively, and reflect the increased electron density in bonds adjoined to two hexagonal rings (C6-C6 bonds) in C60 relative to C70. The log A frequency factor for the reaction of C70 with cyclopentadiene is over twice that for C60 because of the presence of a greater proportion of C6-C6 bonds.