Dual emission and pH based naphthalimide derivative fluorescent sensor for the detection of Bi3+

This paper describes a novel dual emission N-hydroxy 1,8-naphthalimide (NHN) sensor for selective determination of Bi3+ ion and pH. This chemosensor displayed a red shift in absorption spectra and fluorescence enhancement towards highly selective Bi3+ ion in neutral aqueous solution. The binding stoichiometry of NHN with Bi3+ have been determined to be 1: 1 by the job's plot and the binding constant is calculated by Benesi-Hildebrand relation. The effect of beta-cyclodextrin (beta-CD) on NHN is also studied at pH similar to 7. The binding mode of NHN with Bi3+ through carbonyl and the hydroxyl group of NHN is confirmed by FT-IR spectra. The influence of hydroxyl group in naphthalimide as a function of pH and metal ions was studied by UV-vis and fluorescence spectroscopy. Fluorescence emission of naphthalimide varied in a narrow range of pH (5-9) and was only slightly influenced by the addition of metal ions in aqueous solution. (C) 2017 Elsevier B.V. All rights reserved.