Selective azo dye-based colorimetric chemosensor for F^-, CH₃COO^- and PO₄³

Area of Science:

• Analytical Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Developing effective anionic receptors remains a significant challenge in chemistry.
• Hydrogen bonding interactions are crucial for selective analyte recognition.
• Azobenzene derivatives offer potential as versatile chemosensors.

Purpose of the Study:

• To evaluate the anion recognition properties of 2-(4-hydroxiazobenzene)benzoic acid (HABA).
• To investigate the use of HABA as a selective chemosensor for specific anions.
• To determine the sensitivity and detection limits of HABA for target anions.

Main Methods:

• Spectrophotometric titrations (UV-Vis) were employed to study the interactions between HABA and various anions.
• Proton Nuclear Magnetic Resonance (¹H NMR) titrations were used to confirm binding interactions and association constants.
• The chromophore's spectral changes were analyzed to quantify anion binding.

Main Results:

• HABA exhibited significant interactions with fluoride, acetate, and phosphate anions.
• UV-Vis spectroscopy showed a distinct spectral shift upon anion binding, indicating chelation.
• Association constants were determined, and ¹H NMR confirmed hydrogen bonding interactions, particularly via the carboxylic acid group.

Conclusions:

• HABA is a sensitive and selective chemosensor for fluoride, acetate, and phosphate.
• The compound effectively utilizes hydrogen bonding for anion recognition.
• HABA demonstrates a low limit of detection, making it suitable for detecting low concentrations of these anions.