Synthesis and characterization of chromone-based ligand and its fluorescence property towards Zn2+

Abstract

Zinc (Zn) is a type of element that are commonly found in the Earth’s environment and may be originated either naturally from the environment or produced by human activities. Zn has been identified as a hazardous metal which can give harmful effects to human health and Earth’s environment. Therefore, it is very important to develop a simplest method which does not require laborious work in order to detect Zn metal ions. Ligand of AFCMSH was synthesized by the mean of reflux reaction between 2-amino-3-formylchromone (AFC) and 4methylbenzenesulfonylhydrazide (MSH). The molecular structure of the ligand in the ground state was optimized using density functional theory (DFT/B3LYP) method with 6-311G(d,p) basis set. Characterization of ligand was conducted using spectroscopic techniques such as Fourier Transform Infra-Red spectroscopy (FT-IR), Gas Chromatography Mass Spectrometry (GC-MS), Nuclear Magnetic Resonance spectroscopy (NMR) and Ultraviolet-visible spectroscopy (UV-VIS). Meanwhile the fluorescence property of ligand in the presence of metal cations was recorded using Fluorescence Spectrophotometer. Ligand shows almost no fluorescence property in the presence of various metal ions except for Zn2+ ion when observed under UV light. Interestingly, ligand exhibits a remarkable fluorescence response by giving yellow-green fluorescence with strong fluorescence intensity in the emission spectrum at 501nm at excitation of 375 nm upon addition of one equivalent of Zn2+.