The inclusion complexation of new methylene blue (NMB) with cucurbituril (CB) was studied spectrophotometrically. It was found that CB forms a 1:1 inclusion complex with NMB in alcohol-water mixtures and the structure of the inclusion complex has been established by 1H-NMR measurements. We have determined the association constants of CB with NMB under high pressures. The association constants of CB increase as the external pressure and solvent polarity increase. Pressure dependence experiments enabled us to calculate the reaction volume for inclusion of CB to range from -15.8 to -10.8 cm3 mol-1. From analyses of the high-pressure results, the volume change caused by water and/or alcohol molecules repelled from the CB cavity in the alcohol-water mixtures was evaluated, which is indicative of the presence of water and/or alcohol molecules in the CB cavity in the alcohol-water mixtures. The volume of molecules repelled from the CB cavity plays an important role in the volume change upon inclusion.
- Inclusion complexation
- Pressure effect
- Solvent effect
ASJC Scopus subject areas
- Physical and Theoretical Chemistry