FLUORESCENT DETECTION OF IODIDE IONS USING COUMARIN DERIVATIVES: INSIGHTS INTO ELECTRON TRANSFER MECHANISM

Abstract

Sensitive and reliable detection of iodide ion (I⁻) is of considerable importance due to its vital role in environmental, biological, and industrial systems. In the present study, the iodide ion sensing capabilities of three the structurally different coumarin derivatives namely, 6-chloro-4-(4-methoxyphenoxymethyl)-chromen-2-one (S1), 1-(4-methoxyphenoxymethyl)-benzo[f]chromen-3-one (S2), and 6-methoxy-4-(4-methoxyphenoxymethyl)-chromen-2-one (S3) are systematically investigated in dimethyl sulfoxide (DMSO) at room temperature. Steady-state and time-resolved fluorescence spectroscopic techniques are employed to evaluate these interactions. Fluorescence experiments through incremental addition of iodide ions revealed the quenching of coumarin derivatives fluorescence, and analysis was carried out using Stern–Volmer plots to examine the mechanism. The change in Gibbs free energy change (ΔG⁰), is estimated to explore the role of photoinduced electron transfer (PET). In addition, the capabilities of investigated coumarin derivatives for rapid and visual detection of iodide ion is examined by solution mode detection method. This study provides a comprehensive assessment of coumarin-based fluorophores as sensing platforms for iodide ion detection.