Triptycene Walled Glycoluril Trimer: Synthesis and Recognition Properties

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Host-Guest Chemistry

Background:

• Cucurbit[n]urils (CB[n]) are macrocyclic hosts with a unique structure and strong binding affinities.
• Developing acyclic CB[n]-type hosts with tailored properties is crucial for expanding their applications.
• Triptycene units can impart unique structural and solubility characteristics to host molecules.

Purpose of the Study:

• To synthesize and characterize a novel acyclic CB[n]-type host molecule.
• To evaluate the host's solubility, self-association behavior, and complexation properties.
• To elucidate the structural features and solid-state packing of the new host.

Main Methods:

• Synthesis of the acyclic CB[n]-type host (1).
• Solubility measurements in aqueous solution.
• Isothermal titration calorimetry (ITC) for complexation thermodynamics.
• Proton nuclear magnetic resonance (¹H NMR) spectroscopy to probe complex geometry.
• Single crystal X-ray diffraction for structural analysis.

Main Results:

• A new acyclic CB[n]-type host (1) with triptycene sidewalls was successfully synthesized.
• Host 1 demonstrated good water solubility (≈ 3 mM) and low self-association (K_s = 480 M⁻¹).
• Structural analysis confirmed the host's conformation and solid-state packing.

Conclusions:

• The synthesized acyclic host offers a promising platform for supramolecular chemistry.
• Its favorable solubility and low self-association are advantageous for complexation studies.
• The triptycene sidewalls contribute to the unique structural and packing properties of the host.