Allosteric and Chelate Cooperativity in Divalent Crown Ether/Ammonium Complexes with Strong Binding Enhancement

Area of Science:

• Supramolecular Chemistry
• Computational Chemistry
• Thermodynamics

Background:

• Crown ethers and ammonium ions form complexes with significant binding interactions.
• Understanding cooperativity effects is crucial for designing advanced molecular systems.

Purpose of the Study:

• To investigate thermodynamic and computational aspects of cooperativity in crown ether/ammonium complexes.
• To elucidate the impact of structural modifications on binding affinity and cooperativity.

Main Methods:

• Isothermal titration calorimetry (ITC) for thermodynamic analysis.
• Density Functional Theory (DFT) calculations with implicit solvent models.
• Large-scale molecular dynamics (MD) simulations with explicit solvent.

Main Results:

• Observed binding constants up to 2×10^6 M⁻¹ indicate strong multivalent binding enhancements.
• Chelate cooperativity effects were significant, amplified by structural modifications.
• Exchange of ether oxygen with methylene groups substantially increased binding and cooperativity.

Conclusions:

• Detailed thermodynamic and computational insights into binding mechanisms were achieved.
• Understanding these effects facilitates the rational design of supramolecular architectures.
• The study provides a foundation for constructing complex systems using multivalent building blocks.