Synthesis and characterization of coumarin derivatives for chemosensor application via experimental and theoretical approaches

Abstract

Coumarin-based fluorescence probes are potential candidates for selective sensing of explosive materials and toxins. In this present study, we designed and developed novel coumarin derivatives with minor modifications from coumarin and sesamol by a simple condensation method. Moreover, the prepared coumarin derivatives, such as 6BMC and 7BMC were characterized by different spectroscopic analyses. The photophysical properties were analyzed through steady-state absorption and fluorescence spectral studies. The substitution of a methyl group strongly affects the non-radiative deactivation as a result, the hyperconjugation increases for 7BMC than 6BMC. The fluorescence probe was used to detect numerous nitroaromatic compounds and demonstrated a rapid, highly selective, and sensitive fluorescence 'Turn Off' response to picric acid (PA) in a THF/H₂O solution, among other nitroaromatics. The fluorescence "Turn Off" response in the presence of PA is due to the photoinduced electron transfer, as proven by lifetime measurements and DFT analysis. The calculated limit of detection is 0.36 and 0.57 μM for 6BMC and 7BMC, respectively. The findings indicate that the coumarin derivatives are efficient probes for selective sensing of picric acid at a micromolar level.