The interaction of 4-sulfonatocalix[6]arene (SCX6) macrocycle with 1-alkyl-3-methylimidazolium type of ionic liquids possessing dodecyl, tetradecyl, or hexadecyl substituent was studied in aqueous solution at 298 K. Host-guest complexation promoted the spontaneous self-assembly into nanoparticles of 7:1 ionic liquid:SCX6 stoichiometry. Positively charged and stable nanoparticles were produced in solutions of 7-200-fold excess of ionic liquid as compared to the amount of SCX6. The negatively charged nanoparticles formed in solutions having 2-7 ionic liquid:SCX6 molar ratios evolved into larger species. The stability of the nanoparticles increased with the lengthening of aliphatic chain of the ionic liquid. Cryo-TEM experiments showed dense particles generally with spherical shape and multilayered structure, which has been confirmed by small-angle neutron scattering.

Inclusion of 6-methoxy-1-methylquinolinium (C 1 MQ) in the cavity of cucurbit [7]uril (CB7) was studied by absorption, fluorescence, NMR and isothermal calorimetric methods in aqueous solution at 298 K. The free C 1 MQ exhibited dual-exponential fluorescence decay kinetics due to the two torsional isomers differing in the orientation of the methoxy moiety relative to the heterocyclic ring. The enthalpy-driven encapsulation of the heterocycle in CB7 led to very stable 1:1 complex with a binding constant of (2.0±0.4)×10 6 M −1. The rate of C 1 MQ−CB7 complex dissociation was found to be comparable to the NMR timescale.Because the methoxy moiety is oriented outward from the host, its s-cis−s-trans isomerization is slightly affected by the confinement. Inclusion complex formation significantly slowed down the photoinduced electron transfer from I − and N 3 − to the singletexcited C 1 MQ, but did not preclude the reaction because long distance electron transfer occurred through the wall of CB7 macrocycle. Due to the large difference in the quenching rate constant for free and encapsulated forms, C 1 MQ is an excellent probe for the study of the inclusion of nonfluorescent compounds in CB7 in the presence of Cl − or Br − .

The effect of temperature and NaCl concentration variations on the self-assembly of 1-methyl-3-tetradecylimidazolium (C 14 mim + ) and 4-sulfonatocalix[6]arene (SCX6) was studied by dynamic light scattering and isothermal calorimetric methods at pH 7. Inclusion complex formation promoted the self-assembly to spherical nanoparticles (NP), which transformed to supramolecular micelles (SM) in the presence of NaCl. Highly reversible, temperatureresponsive behavior was observed, and the conditions of the NP−SM transition could be tuned by the alteration of C 14 mim + :SCX6 mixing ratio and NaCl concentration. The association to SM was always exothermic with enthalpy independent on the amount of NaCl.In contrast, NPs were produced in endothermic process at low temperature, and the enthalpy change became less favorable upon increase of NaCl concentration. The NP formation was accompanied by negative molar heat capacity change, which further diminished when NaCl concentration was raised.