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Journal of Chemistry
Volume 2015, Article ID 165295, 9 pages
http://dx.doi.org/10.1155/2015/165295
Research Article

Synthesis of Novel Fluorescent Sensors Based on Naphthalimide Fluorophores for the Highly Selective Hg2+-Sensing

1Department of Chemistry, Faculty of Science, Silpakorn University, Nakhon Pathom 73000, Thailand
2Department of Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
3Chemistry Program, Faculty of Science and Technology, Nakhon Pathom Rajabhat University, Nakhon Pathom 73000, Thailand

Received 27 November 2014; Revised 15 January 2015; Accepted 26 January 2015

Academic Editor: Pedro Derosa

Copyright © 2015 Yordkhuan Tachapermpon et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

With an aim to develop the new sensors for optical detection of Hg2+ ions, two novel fluorometric sensors were designed and successfully prepared using 2-(3-(2-aminoethylsulfanyl)propylsulfanyl)ethanamine and one or two N-methylnaphthalimide moieties (1 and 2). Sensor 1 was obtained via N-alkylation, N-imidation and a one-pot nucleophilic aromatic substitution, and N-formylation of the amine, while sensor 2 was prepared via N-alkylation, N-imidation, and nucleophilic aromatic substitution. The characterization, including 1H NMR, 13C NMR, and mass spectrometry, was then performed for 1 and 2. The Hg2+-binding behaviors of the sensors were investigated in terms of sensitivity and selectivity by fluorescence spectroscopy. Sensor 1 especially provided the reversible and highly Hg2+-selective ON-OFF fluorescence behavior by discriminating various interfering ions such as Pb2+, Co2+, Cd2+, Mn2+, Fe2+, K+, Na+, and in particular Cu2+ and Ag+ with a detection limit of 22 ppb toward Hg2+ ions.