Molecular Recognition in an Aqueous Medium Using Water-Soluble Prismarene Hosts

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry

Background:

• Prismaranes are macrocyclic compounds with unique structural properties.
• Water-soluble derivatives are desirable for various applications, including host-guest chemistry.

Purpose of the Study:

• To synthesize novel water-soluble prismarenes (n=5 and 6) with anionic carboxylato groups.
• To investigate the binding properties and thermodynamics of these hosts with ammonium guests.

Main Methods:

• Synthesis of water-soluble prismarenes.
• Nuclear Magnetic Resonance (NMR) spectroscopy.
• Isothermal Titration Calorimetry (ITC).

Main Results:

• Successful synthesis of water-soluble prism[5]arene and prism[6]arene.
• Pentamer complexation with ammonium guests is enthalpically driven by secondary interactions.
• Hexamer complexation thermodynamics are influenced by guest charge and size.

Conclusions:

• The synthesized prismarenes represent a new class of water-soluble hosts.
• The binding mechanisms differ between the pentamer and hexamer, highlighting the effect of macrocycle size and rigidity.