An Adaptive Cholic Acid Dimer for Selective Encapsulation.

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Host-Guest Chemistry

Background:

• Bile acids are natural molecules with potential for synthetic modification.
• Developing novel host molecules is crucial for molecular recognition and encapsulation.
• Understanding host-guest interactions informs the design of new functional materials.

Purpose of the Study:

• To synthesize a novel cleft-type cholic acid dimer.
• To characterize the dimer's structure and guest-binding capabilities.
• To investigate the dimer's interactions with polar and nonpolar guests.

Main Methods:

• Six-step synthesis of the cholic acid dimer.
• Structural elucidation using FTIR, 1D NMR (¹H, ¹³C, DEPT135), 2D NMR (COSY, HSQC, HMBC), and ESI-MS(+).
• Host-guest complexation studies using UV-Vis absorption, in silico simulations, molecular modeling, and steady-state fluorescence.

Main Results:

• Successful synthesis and full structural characterization of the cleft-type cholic acid dimer.
• The dimer demonstrated the ability to entrap both polar and nonpolar guests.
• Moderately stable 1:1 host-guest complexes were formed with Cresol Red sodium salt and pyrene.
• Guest binding interactions were primarily dynamic or collisional in aqueous environments.

Conclusions:

• A novel cholic acid dimer with adaptable binding pockets was successfully synthesized.
• The dimer exhibits potential for molecular recognition and encapsulation of diverse guests.
• The study provides insights into the binding mechanisms and stability of bile acid-derived host molecules.