By the common Soxhlet extraction with 1,2,4-trichlorobenzene a mere 8
mass % of virgin fullerene soot can be dissolved. The extracted soot w
as subjected to a reactive extraction with 5-hexadecanamido-1,3-dihydr
o-2-benzothiophene 2,2-dioxide (4), an ortho-quinodimethane precursor.
Through an irreversible Diels-Alder cycloaddition an additional 12 ma
ss % was solubilized. Mass spectrometry, vapour pressure osmometry and
elemental analysis indicate that the soluble material consists of mul
tiple adducts of fullerenes C-60-C-418.