Thermodynamic study of the complexes of calix[4]naphthalenes with [60]fullerene in different solvents

Abstract

Calix[4]naphthalenes are a class of molecules which possess deeper cavities than those of the analogous calix[4]arenes. Preliminary data obtained for the complexation of [60]fullerene (“C60”) with the C4-symmetrical endo-calix[4]naphthalene 3 and its tert-butyl-substituted derivative 4 show that they form supramolecular 1∶1 complexes with C60 in benzene, toluene or CS2 solution with relatively high association equilibrium constants (Kassoc). Reported herein are thermodynamic parameters and additional Kassoc determined for the complexation of C60 and calix[4]naphthalenes 3 and 4 which show that both a solvophobic effect and π–π interactions are major driving forces for the complexation process.