Oxime-based receptors for mono- and disaccharides

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Carbohydrate Chemistry

Background:

• Development of synthetic receptors for selective molecular recognition is crucial in supramolecular chemistry.
• Acyclic receptors offer unique structural flexibility compared to macrocyclic counterparts.
• Understanding host-guest interactions in non-aqueous media is important for various applications.

Purpose of the Study:

• To synthesize and characterize a new series of acyclic oxime-based receptors.
• To investigate the binding properties of these receptors towards neutral sugar molecules.
• To elucidate the binding modes and driving forces involved in receptor-sugar complexation.

Main Methods:

• Synthesis of novel acyclic oxime-based receptors.
• 1H NMR titration experiments to study binding interactions.
• Fluorescence titration assays to quantify binding constants.
• Molecular modeling to predict and rationalize binding modes.

Main Results:

• Receptors 2a and 2b formed strong 1:1 complexes with dodecyl alpha- and beta-maltoside (Ka1 ~ 10^5 M^-1) in chloroform.
• Complexation with beta-glucopyranoside showed 1:1 and 1:2 receptor-monosaccharide stoichiometry (overall binding constant beta2 ~ 10^5 M^-2).
• Binding is stabilized by hydrogen bonding and interactions between sugar C-H bonds and receptor phenyl rings.

Conclusions:

• Acyclic oxime-based receptors demonstrate effective binding of neutral sugars.
• The receptor design allows for tunable binding stoichiometry.
• Synergistic effects of hydrogen bonding and hydrophobic interactions contribute to complex stability.