Crown Ether Functionalized Barbituric Acid for Colorimetric Determination of Au3+

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ABSTRACT

In this study, we report the successful synthesis of a novel benzo crown ether-functionalized barbituric acid derivative (receptor 3) as a colorimetric probe for detecting Au³⁺ ions in aqueous solutions. The receptor was synthesized using a straightforward Knoevenagel condensation between 4, 4’-diformyl dibenzo-15-crown-5 ether and barbituric acid in methanol at room temperature, yielding the product in good quantities. This receptor demonstrated excellent selectivity and sensitivity towards Au³⁺ ions over other common cations, enabling rapid visual detection without the need for advanced instrumentation. Upon interaction with Au³⁺, receptor 3 caused a distinct color change in the solution from colorless to violet, which could be observed with the naked eye. The detection limit of receptor 3 was calculated to be as low as 2.95×10⁻⁵ molL⁻¹, making it highly suitable for detecting trace amounts of Au³⁺ in real-world applications. The optical properties of the receptor were further characterized using various techniques, confirming its stability and efficacy in aqueous medium (DMSO+H₂O, 1:4 v/v). This newly developed sensor holds significant potential for practical applications, particularly in environmental monitoring and gold ion detection in industrial processes, offering a cost-effective and simple alternative to more complex detection methods.

Significance of the Study:

This study highlights the development of a highly selective and sensitive colorimetric sensor for detecting Au³⁺ ions. The novel benzo crown ether-functionalized barbituric acid derivative offers a simple, cost-effective, and visual detection method without the need for advanced instrumentation. This approach is significant for practical applications in environmental monitoring and industrial processes, where rapid and accurate detection of gold ions is essential. The innovation in detection methodology addresses current limitations in complex and expensive instrumentation, presenting an accessible solution for on-site monitoring.

Summary of the Study:

The research successfully synthesized a new crown ether-functionalized barbituric acid derivative (receptor 3) as a colorimetric probe for detecting Au³⁺ ions. Receptor 3 exhibited remarkable selectivity and sensitivity towards Au³⁺, producing a distinct color change from colorless to violet upon ion interaction, visible to the naked eye. The probe’s detection limit was 2.95 × 10⁻⁵ molL⁻¹ in a DMSO-water solution, proving its efficiency for trace-level detection. This simple and cost-effective sensor offers significant potential for practical applications in environmental and industrial gold ion monitoring.