Clusters of Bis- and Tris-Fullerenes

Bis- and tris-fullerene derivatives [bis-(C 60 ) and tris-(C 60 )] form suspendable clusters in mixed solvents (80% acetonitrile and 20% toluene). These clusters are optically transparent and exhibit interesting nanostructures with sizes ranging from 100 nm to 1 μm and shapes varying from elongated wires to entangled spheres. Ground- and excited-state properties of the clusters of the mono-, bis-, and tris-fullerene derivatives are compared with the corresponding properties of their monomeric forms through steady-state and time-resolved transient absorption spectroscopy. The singlet excited-state quenching of bis- and tris-fullerene derivatives by N -methylphenothiazine (NMP) occurs with rate constants of 5.5 × 10 9 and 5.3 × 10 9 M - 1 s - 1, respectively. The charge separation in these clustered fullerene derivatives is probed by monitoring the formation and decay of the C 60 radical anion and the radical cation of NMP. An increase in the number of fullerene moieties in the molecule helps in the formation of ordered cluster aggregates and this has a beneficial effect in stabilizing the electron-transfer products.