Synthesis of new

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Analytical Chemistry

Background:

• Calixarenes are versatile macrocyclic hosts with tunable properties.
• Amphiphilic receptors are crucial for self-assembly and molecular recognition.
• Copper-catalyzed azide-alkyne cycloaddition (CuAAC) is a powerful tool for constructing complex molecules.

Purpose of the Study:

• To synthesize novel water-soluble calixarene-based amphiphilic receptors.
• To investigate the self-assembly behavior and aggregation properties of these macrocycles.
• To explore their application in nucleotide sensing.

Main Methods:

• Synthesis of calix[4]arenes with azide functionalities via CuAAC reaction.
• Characterization of macrocycles' aggregation in water using dynamic light scattering and zeta potential measurements.
• Determination of critical aggregation concentrations (CAC) using fluorescence spectroscopy with pyrene and eosin Y probes.
• Nucleotide sensing via dye displacement assay and colorimetric detection using polydiacetylene vesicles.

Main Results:

• Successfully synthesized novel cone-calix[4]arenes bearing azide groups, leading to water-soluble triazolyl amphiphilic receptors.
• Synthesized macrocycles form stable aggregates in water with hydrodynamic diameters of 150-200 nm and positive zeta potentials (+40 to +60 mV).
• Tetraalkyl-substituted macrocycles exhibit significantly lower CAC values (5 µM) compared to dialkyl-substituted ones (160-790 µM).
• Demonstrated nucleotide sensing capabilities, with a preference for adenosine diphosphate (ADP) over adenosine triphosphate (ATP) by disubstituted macrocycles.
• Developed a colorimetric method for naked-eye detection of ADP using polydiacetylene vesicles functionalized with macrocycle 10b, with a detection limit of 0.5 mM.

Conclusions:

• The synthesized calixarene-based receptors self-assemble into stable supramolecular structures.
• The aggregation behavior and nucleotide binding affinity are influenced by the substitution pattern on the macrocycle.
• These novel macrocycles offer a promising platform for sensitive and selective nucleotide detection, including a simple colorimetric assay for ADP.