A benzimidazole-based chromogenic anion receptor

Area of Science:

• Supramolecular Chemistry
• Anion Recognition
• Organic Synthesis

Background:

• Anion sensing is crucial in various chemical and biological processes.
• Developing selective and sensitive anion receptors remains a significant challenge.
• Benzimidazole derivatives offer promising scaffolds for molecular recognition.

Purpose of the Study:

• To design and synthesize a novel benzimidazole-based receptor for selective anion recognition.
• To investigate the binding mechanism and selectivity of the receptor towards halide anions.
• To explore the potential of the receptor as a colorimetric sensor for fluoride.

Main Methods:

• Synthesis of benzimidazole-based receptor 1.
• Single crystal X-ray diffraction for structural confirmation.
• (1)H NMR and UV-visible spectroscopy for anion-binding studies.
• Colorimetric analysis for fluoride detection.

Main Results:

• The synthesized benzimidazole-based receptor 1 was structurally confirmed.
• Receptor 1 demonstrated highly selective recognition of fluoride (F-) over other halide anions (Cl-, Br-, I-).
• Selective fluoride recognition is attributed to strong hydrogen-bond interactions and geometric matching.
• A dramatic color change from light-yellow to red was observed upon fluoride binding, indicating a potential colorimetric sensor.
• The color change remained consistent even in the presence of a large excess of other halides.

Conclusions:

• A novel benzimidazole-based anion receptor has been successfully synthesized and characterized.
• The receptor exhibits excellent selectivity for fluoride ions, driven by hydrogen bonding and structural complementarity.
• The compound functions as an effective colorimetric sensor for fluoride, showing a distinct visual response.
• This work contributes to the development of advanced materials for selective anion detection.