Calix[4]arene Based Highly Efficient Fluorescent Sensor for Au(3+) and I(.).

Area of Science:

• Supramolecular Chemistry
• Analytical Chemistry
• Sensing Technology

Background:

• Calixarene derivatives are versatile platforms for molecular recognition.
• Development of selective sensors for environmentally relevant ions is crucial.
• Fluorogenic and chromogenic sensing offer sensitive detection methods.

Purpose of the Study:

• To synthesize and characterize a novel calixarene derivative (C4NSB).
• To investigate the ion-binding properties of C4NSB for selective cation and anion sensing.
• To evaluate the sensing performance, including selectivity, sensitivity, and stoichiometry.

Main Methods:

• Synthesis of 5,11,17,23-tetratertbutyl-25,27-bis((2hydroxynaphthylimino)1,2-ethylenediaminecarbonylmethoxy)-26,28 dihydroxycalix[4]arene (C4NSB).
• Spectroscopic analysis (fluorescence and UV-Vis) to probe ion binding.
• Investigation of selectivity in the presence of competing ions and characterization using FT-IR spectroscopy.

Main Results:

• C4NSB exhibits a 'turn-off' fluorescence response and high chromogenic selectivity for Au(3+) and I(-).
• The receptor demonstrates selectivity even in the presence of various competing ions.
• Low limits of detection (LOD) were achieved: 1.5 × 10⁻⁵ M for Au(3+) and 4.5 × 10⁻⁶ M for I(-).
• Stoichiometric (1:1) complex formation with binding constants of 8.0 × 10² M⁻¹ for Au(3+) and 15.6 × 10² M⁻¹ for I(-) were determined.

Conclusions:

• C4NSB is a highly selective and sensitive sensor for Au(3+) and I(-) ions.
• The calixarene derivative shows potential for practical applications in ion detection.
• The study highlights the utility of functionalized calixarenes in developing advanced sensing materials.