Ni2+ Ion Sensing by a Semicarbazone Derivative of Piperidin-4-one: A Spectrofluorimetric Study

Nickel ions are toxic to the environment and they are also relevant in biology. Fluorescence sensing is a sensitive method and metal sensing can be carried out employing cheaper and easy-to-synthesize molecules that possess fluorescence emission. Therefore, the development of newer and simply-synthesized chemosensor molecules for nickel ions in aqueous media is required. We report, in this paper, a simple semicarbazone derivative of a piperidin-4-one as a nickel ion sensor in water. The compound forms a 1:1 stoichiometric complex with nickel ions. The association constant value is 4.04 × 104 mol-1 dm3. The nickel ion-selectivity of the compound is explored employing UV-Vis and fluorescence spectroscopy. Ni2+ ion-chelation enhances the fluorescence of the chemosensor molecule. The Ni2+ detection limit of the chemosensor was 1 × 10-7 mol dm-3. The compound also forms a 1:2 inclusion complex with β-cyclodextrin. The structure of the complex is proposed. Host: guest complex formation of β-cyclodextrin with the piperidin-4-one derivative results in the interference of the host molecule with the chelation of Ni2+ ions. As an extension of the application of the piperidin-4-one derivative, we demonstrate the Ni(II) ion filtration by incorporating the compound with a polysulfone film.