Amide cyclodextrin that recognises monophosphate anions in harmony with water molecules

Area of Science:

• Supramolecular Chemistry
• Host-Guest Chemistry
• Chemical Sensing

Background:

• Anion recognition in aqueous environments is challenging due to water molecule interference.
• Synthetic host molecules require sophisticated designs to achieve selectivity in water.

Purpose of the Study:

• To develop a novel macrocycle for precise anion recognition in water.
• To demonstrate selective binding of monophosphate anions.
• To elucidate the distinct binding mechanisms of different phosphate guests.

Main Methods:

• Synthesis of an N-methylpyridinium amide β-cyclodextrin derivative.
• Anion binding studies using NOESY experiments and Isothermal Titration Calorimetry (ITC).
• Molecular Dynamics (MD) simulations to analyze guest-host interactions and hydration.

Main Results:

• The synthesized macrocycle selectively recognized monophosphate anions over sulfonates and carboxylates.
• Two distinct binding modes were observed for phenyl phosphate and adamantyl phosphate.
• Configurational entropy drove phenyl phosphate inclusion, while hydrophobic effects dominated adamantyl phosphate binding.

Conclusions:

• A novel macrocycle design enables precise anion recognition in water via multipoint hydrogen bonding.
• Understanding hydration and guest-specific interactions is crucial for designing functional molecules in aqueous media.
• This work advances the development of synthetic receptors for challenging anion recognition tasks.