ABSTRACT
Carbon nanohorns (CNHs), an alternative of nanotubes with conical
tips and high purity due to the absence of metal impurities, are
assembled in a secondary spherical hyperstructure. Similar with
nanotubes, CNHs are insoluble in all solvents. In this chapter,
the most significant developments on the functionalization and
solubilization of CNHs are presented. Selected examples from the
recent literature have been collected and together with some
original as well as established methodologies are discussed. Among
these, 1,3-dipolar cycloadditions, aryl diazonium addition, Bingel
cyclopropanation, amination, as well as oxidation and subsequent
condensation reactions have been widely applied to covalently
modify the outer skeleton or conical tips of CNHs. Furthermore,
CNHs have been non-covalently functionalized with the aid of
polymer wrapping and π−π stacking interactions with pyrenes or porphyrins. Finally, emphasis is placed on some potential
applications of CNH-based hybrid materials, especially for drug
delivery and photovoltaics.