A thiophene built chalcone as fluorescent chemosensor for silver ions and their applications in strip-paper, ointments, and bio-imaging

Abstract

A simple thiophene based chalcone as fluorescent receptor (ADC) was synthesized by Claisen Schmidt condensation method upon linking 2-acetyl thiophene (1) and N,N-dimethylamino benzaldehyde (2). The synthesized receptor is well characterized by NMR, IR, and mass spectroscopic techniques. The ADC receptor was examined for the detection of metal ions, in which it had a noticeable blue shifted fluorescence enhancement for Ag+ ions. Upon binding towards Ag+ ions, the photoinduced electron transfer (PET) process is inhibited via intramolecular charge transfer (ICT) process taking place. The binding stoichiometry of ADC + Ag+ complexation ratio is noted to be 2:1, which was further confirmed by jobs plot method, 1H NMR titration, IR spectral analysis, and DFT studies. The limit of detection (LOD) and limit of quantification (LOQ) was found to be 4.98 µm and 6.36 µm respectively. Additionally, ADC showed color changes upon binding with Ag+ ions in strip paper, cotton swab test through UV-365 nm illumination. Moreover, ADC was successfully utilized for the practical applications of Ag+ ion detection in water samples, ointment and bacterial cell lines.