Synthesis and ESIPT Phenomena of A New -Naphthol Derivative, An Experimental and In Silico Study

Abstract

A new derivative based on -naphthol skeleton was successfully synthesized through Knoevenagel condensation as a yellow solid with an overall chemical yield of 28% in two steps. The compound showed maxima of UV/Visible and emission spectra in acetonitrile at 404 nm and 521 nm respectively. Based on spectroscopy data of FTIR, ToF-HRMS, 1H-NMR and 13C-NMR, the product was characterized as 4-((2-hydroxynaphthalene-1-yl)methylene)pyrazolidine-3,5-dion. Chelation experimental study of the compound against various metal ions in acetonitrile exhibited fluorescence enhancement by three folds of magnitude, especially against Al3+ and Mg2+ at emission maxima of 521 nm. The LoD and LoQ of the compound were respectively calculated to be 0.004 mg L-1 and 0.013 mg L-1 for Al3+ and 0.002 mg L-1 and 0.008 mg L-1 for Mg2+. DFT and TD/DFT calculations revealed that the interaction mechanism of the compound with the metal ions was through inhibition of excited-state intramolecular proton transfer (ESIPT).