Rigid rod spaced fullerene as building block for nanoclusters

By using phenylacetylene based rigid-rod linkers (PhA), we have successfully synthesized two fullerene derivatives, C60–PhA and C60–PhA–C60. The absorption spectral features of C60, as well as that of the phenylacetylene moiety are retained in the monomeric forms of these fullerene derivatives, ruling out the possibility of any strong interaction between the two chromophores in the ground state. Both the fullerene derivatives form optically transparent clusters, absorbing in the UV-Vis region; this clustering leads to a significant increase in their molar extinction coefficients. TEM characterization of the C60–PhA showed large spherical clusters, with sizes ranging from 150–350 nm, while an elongated wire-type structure was observed for the bisfullerene derivative (C60–PhA–C60). AFM section analysis studies of isolated nanoclusters of C60–PhA–C60, deposited on mica, indicate that smaller clusters associate to form larger nanostructures.