Mechanism of complexation of the phenothiazine dye methylene blue with fullerene C60

The complexation of fullerene C₆₀ with the aromatic dye methylene blue (MB) in aqueous solution was studied. Spectrophotometric titration revealed a reasonably strong interaction between C₆₀ and MB molecules with an equilibrium constant K = 2110 L/mol and the binding of up to five dye molecules with the surface of C₆₀. The energy analysis of the MB-C₆₀ system showed that the intermolecular and hydrophobic interactions were dominant in the energy profile of the complexation, and while the electrostatic factor played an insignificant role.