Direct preparation of radioactive fullerenes as a tracer for applications

The C60 and C70 fullerenes were irradiated by high-energy gamma-rays and charged particles. The irradiated samples were dissolved in CS2 and/or toluene and filtered to remove insoluble by-products. Finally, radioactive fullerenes and products labeled with 11C or 13N were isolated and detected in the liquid phase by radiochromatography. It was found that (1) not only 11C or 13N radioactive monomer fullerenes but also their dimers (trimers and, possibly, tetramers) were produced by recoil implantation process following nuclear reaction and (2) the radioactive fullerene labeled with 11C yields has led to high yields.