Effects of external pressure and solvent polarity on inclusion complexations of phenothiazine dyes and trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium with water-soluble p-sulfonatocalix[8]arene in alcohol-water mixtures

摘要

The effects of pressure and solvent were examined for the inclusion complexation of phenothiazine dyes and trans-4-[4-(dimethylamino)styryl]-1-methylpyridinium(St-4Me)with water-soluble beta-suIfonatocalix[8]arene(Calix-S8).Depending on the bulkiness of the guest dyes,external pressures and solvent polarity increase the inclusion equilibrium constants of dyes with Calix-S8.From the pressure dependence of the inclusion equilibria,the reaction volumes for inclusion by Calix-S8 in the alcohol-water mixtures were estimated to be negative values(-19.8 to-5.29 cm~3 mol~(-1)for the phenothiazine dyes and-13.1 to-9.85 cm~3 mol~(-1)for St-4Me).Analysis of the results of the high pressure indicated that the intrinsic volume change related to inclusion into the Calix-S8 cavity plays an important role in the inclusion of Calix-S8,depending on the bulkiness of the guest molecules.Based on ~1H NMR measurements,the structures of the inclusion complexes of Calix-S8 with phenothiazine dyes have been established and the differences in the inclusion behaviors of the phenothiazine dyes and St-4Me are discussed.