Unveiling Moisture Detection, Selective Sensing of Zn²⁺ ion, Antibacterial Analysis of 2-Amino Thiazole-Based Schiff...

Development fluorescence chemosensor for selectively detection of a particular analyte intriguing tuning environmental, biological and pharmaceutical applications. In this regard, a simple and cost-effective Schiff base molecular probe, namely, (E)-3-((thiazol-2-ylimino)methyl)-4 H-chromen-4-one (L) was designed. The molecular probe (L) was used to detect trace amounts of water in DMSO. Upon addition of water, to the DMSO solution of L, the fluorescence emission band decreased significantly, this phenomenon suggests that the quenching in fluorescence emission was attributed to the formation of aggregates, indicating characteristics of aggregation-caused quenching-emission (ACQE). On the other hand, the probe (L) was selectively sensing Zn²⁺ ions over other metal ions. The change in emission band (blue shifted ~ 68 nm) is due to supersession of photo-induced electron transfer (PET) and inhibition of -C = N isomerisation. Using the Benesi-Hilderbrand plot, the binding stoichiometry is found to be 1:1. Theoretical calculations (DFT and TDDFT) have been explored to find the binding mechanism of the formation of the complex. Using four clinical drug-resistant microorganisms, the disc diffusion technique was used to perform the antibacterial test of L and L-Zn²⁺. The highest ZOI of these is seen in B. subtilis and S. aureus, which had diameters of 13 mm and 15 mm in L-Zn²⁺ and 10 mm and 12 mm in L and lowest ZOI was found in E. coli and K. pneumoniae with 12 mm and 11 mm in L-Zn²⁺ and 8 mm and 6 mm in L. Even at the lowest dose in both samples, the MIC and MBC analyses verify that there is around 99.9% inhibition.