Host-guest interaction of tryptophane with acid-functionalized calix[4]pyrrole: a fluorescence-based study

Area of Science:

• Supramolecular Chemistry
• Analytical Chemistry
• Chemical Sensing

Background:

• Calix[4]pyrroles are versatile platforms for developing host-guest molecular sensors.
• Flexible functionalization of calix[4]pyrroles allows tailoring receptors for specific applications.
• Acid functionalization can enhance ligand solubility and host-guest interactions.

Purpose of the Study:

• To investigate the binding behavior of an acid-functionalized calix[4]pyrrole derivative (TACP) with various amino acids.
• To explore the potential of TACP as a fluorescent molecular sensor for amino acid detection.
• To confirm the binding interactions through computational and spectroscopic methods.

Main Methods:

• Synthesis and characterization of the acid-functionalized calix[4]pyrrole derivative (TACP).
• Fluorescence spectroscopy to monitor binding events with different amino acids.
• Determination of limit of detection (LOD) and limit of quantitation (LOQ).
• Computational docking studies and Nuclear Magnetic Resonance (NMR) complexation studies.

Main Results:

• TACP demonstrated significant fluorescence enhancement specifically in the presence of tryptophan.
• No considerable fluorescence changes were observed with other tested amino acids.
• The ligand-amino acid complex exhibited a 1:1 stoichiometry.
• LOD and LOQ values were determined to be 25 µM and 22 µM, respectively.
• Binding phenomena were validated by docking and NMR studies.

Conclusions:

• Acid functionalization of calix[4]pyrroles enhances their utility as molecular sensors.
• TACP shows high selectivity and sensitivity for tryptophan detection.
• This approach holds promise for developing advanced molecular sensors for amino acid analysis.