The kinetics of addition of cyclopentadiene to fullerene C60 and fulle
rene C70 have been studied in the temperature range 291-354 K by high-
pressure liquid chromatography. The rate of addition of cyclopentadien
e 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 elect
ron 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 C7
0 with cyclopentadiene is over twice that for C60 because of the prese
nce of a greater proportion of C6-C6 bonds.