Abstract Submitted to the    NANOTUBE'04 Conference:

One-dimensional molecular arrays assembled inside nanotubes exhibit functional properties different to the bulk crystal and promise to find many applications ranging from catalysis to quantum computing. We discovered that single-walled carbon nanotubes can be efficiently filled with fullerenes in supercritical fluids at temperatures as low as 30-50 deg. C. Despite the low solubility of fullerenes in supercritical fluids the nanotube filling was particularly effective in supercritical carbon dioxide producing Cn@SWNT structures in 70% yield at 50 deg. C. This method was applied for functionalized and endohedral fullerenes C61(COOEt)2, Er3N@C80, and N@C60. We demonstrate that this method allows insertion of thermally unstable molecules which would be impossible to insert in nanotubes using standard techniques. We discuss the advantages of using supercritical fluids as compared to conventional solvents and propose the mechanism for fullerene encapsulation at low temperatures.