Photoswitchable Supramolecular Systems Based on Carboxyl Derivatives of Thiacalix[4]arene and Their Complexes with Zn(II) and Tb(III) Ions

Self-Organization and Physicochemical Properties of Aqueous Solutions of the Sodium Salt of Azosulphonate Calix[4]arene

“…It is in these concentration intervals that ε first increases from 27900 to 48700 (1.5•10 -5 and 1•10 -5 M, respectively), maintaining constancy to 5•10 -6 M, and then non-monotonously falling to 39230 at 1•10 -6 M. Thus, the nonlinear change in optical absorbance in the dispersed system of macrocycle 1 in the region of 1•10 -6 -1.5•10 -5 M is a consequence of the process of rearrangement of the dispersed phasemolecular-water domains. It was previously shown [6] that under UV irradiation with a wavelength of 254 nm (8 mV) of solutions of thiacalix [4]arenes in the stereoisomeric form of 1,3-alternate, containing an azoaryl group, photoisomerization around N=N bond occurs in a 30 minutes period. To study the photoisomerization of the azo-group in macrocycle 1, which is in the cone conformation, the solutions of this compound were irradiated under similar conditions [5] in the concentration range 1•10 -3 -1•10 -5 M. Comparison of the UV spectra of the solutions and the size distributions by intensity before and after irradiation throughout the studied range of concentrations and irradiation time did not reveal significant differences.…”

“…[1][2][3][4][5] In the last decade, much attention has been paid to the study of the synthesis methods, properties and applications of azosulfonate calix [4] arenes (ASC) and their derivatives. [6,7] Water-soluble ASC are promising compounds that may have photo-switching properties, [8,9] which allows managing the self-organization and physicochemical properties of the substance in solution. However, the processes of self-organization and physicochemical properties of ASC solutions have not been systematically studied in a wide range of concentrations.…”