Diphenylpolyene-cholesterol conjugates as fluorescent probes for microheterogeneous media

• Cholesterol was covalently linked to donor–acceptor diphenylpolyenes.
• Photophysical studies establish remarkable intramolecular charge transfer behaviour.
• Probing microenvironments of micelles revealed bi-exponential decay profile indicating preferential interaction.

Extrinsically conjugated fluorescent diphenylpolyene cholesterol derivatives are synthesized and spectroscopic investigations in homogeneous and aqueous micellar solutions are described. The emission of these cholesterol conjugates reveals characteristic intra-molecular charge transfer (ICT) behaviour in homogeneous solvents with a mono-exponential decay. Spectroscopic evidence in micellar aqueous solutions reveals a bi-exponential decay. This indicates the presence of two preferred locations of the cholesterol conjugated diphenylpolyenes sites of lower polarity and interfacial sites. The sensitivity of these fluorophores was utilized to determine the critical micelle concentrations.

Figure optionsDownload as PowerPoint slide