Water-soluble host-guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres

A sugar-functionalized water-soluble tribenzotriquinacene derivative bearing six glucose residues, TBTQ-(OG) 6 , was synthesized and its interaction with C 60 - and C 70 -fullerene in co-organic solvents and aqueous solution was investigated by fluorescence spectroscopy and ultraviolet-visible spectroscopy. The association stoichiometry of TBTQ-(OG) 6 ⊂ C 60 and TBTQ-(OG) 6 ⊂ C 70 was found to be 1 : 1 with binding constants of K a = 3.7 × 10 4 M –1 and K a = 8.5 × 10 4 M –1 , respectively. The binding affinity between TBTQ-(OG) 6 and C 60 was further verified by Raman spectroscopy. The geometry of TBTQ-(OG) 6 ⊂ C 60 deduced from DFT calculations indicates that the driving force of the complexation is mainly due to the hydrophobic effect and to host-guest π-π interactions. Hydrophobic surface simulations showed that TBTQ-(OG) 6 ⊂ C 60 forms an amphiphilic supramolecular host-guest complex, which further assembles to microspheres with diameters of 0.3–3.5 μm, as determined by scanning electron microscopy.