Modulation of Photo-Signal Based on Molecular Recognition by Steroid Cyclophane in Liquid Assembly

Abstract The binding of a fluorescent probe (TNS) in aqueous mixtures of a steroid cyclophane and an artificial lipid was spectrophotometrically investigated. When the content of the steroid cyclophane is dominant ([lipid]/[cyclophane] = 0.1), the fluorescent maximum of the bound TNS is 433 nm. At the [lipid]/[cyclophane] ratio of 5, the fluorescence maximum is ca. 409 nm, indicating that the host cavity provided a more hydrophobic environment. A large excess of lipid reversed the fluorescence maximum up to 426 nm, i.e., the host cavity became hydrophilic again. The change in emission maxima of the bound TNS is modulated by the hydrophobic-hydrophilic cavity conversion.