D–π–A chalcone analogue as metal ions selective turn-on-off-on fluorescent chemosensor with cellular imaging and corrosion protection

Abstract

Novel naked eye optical chemosensor containing thiazole ring, namely; (2E,4E)-5-(4-(dimethylylamino)phenyl)-1-(thiazol-2-yl)penta-2,4-dien-1-one, DMAPTP was developed. The solvatochromic response was explored in different solvents of various polarities. The dipole moments in the ground (µg) and excited (µe) states were determined. The large excited state dipole moment demonstrates the excited state's stability in polar solvents. In an ethanolic solution, the sensing response and selectivity of the investigated chemosensor to various metal ions such as Na+, K+, Ca2+, Ba2+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Al3+, Hg2+, and Pb2+ were evaluated. The spectral changes suggest that DMAPTP is strongly complexed with the metal ions used. The ground and excited state binding constants, as well as the quenching constants, have been determined. The mechanism of fluorescence quenching was identified as static quenching due to the formation of a non-fluorescent ground state complex using the Stern-Volmer plot. DMAPTP can also be used as a powerful chemosensor, identifying all of the metal ions studied with high sensitivity and selectivity for Fe3+ ions. DMAPTP can serve as a Turn-on-off-on chemosensor, as well as a metallochromic predictor in complexometric titration. This is indicated by the ability of EDTA to decompose the formed complex with the formation of the stable metal-EDTA complex, which leads to fluorescence recovery. The analytical parameters, such as selectivity, sensitivity, and detection limit, were chosen. The fluorescence imaging experiments in living cells demonstrated the biological chemosensing applications of DMAPTP to Fe3+ ions. Furthermore, weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy, and scanning electron microscopy techniques were used to investigate DMAPTP as a corrosion inhibitor for carbon steel in 1.0 M HCl. The collected data reveal that as DMAPTP concentrations increased, its inhibition performance increased as well. On the basis of strong adsorption of inhibitor molecules on the surface of carbon steel and the formation of large protection films, the inhibition efficiencies were determined.