Isophthaloyl-Based Selective Fluorescence Receptor for Zn (II) Ion in Semi-Aqueous Medium

• Published in: Journal of fluorescence 2019-07, Vol.29 (4), p.837-843
• Main Authors: Khadke, N. B., Patil, A. A., Patil, D. Y., Borhade, A. V.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Aqueous solutions; Binding; Biochemistry; Biological and Medical Physics; Biomedical and Life Sciences; Biomedicine; Biophysics; Biotechnology; Density functional theory; Electrochemical analysis; Electron transfer; Fluorescence; Hydroxyl groups; Original Article; Stoichiometry; Zinc; Zinc coordination
• ISSN: 1053-0509; 1573-4994
• DOI: 10.1007/s10895-019-02385-1

A novel Isophthaloyl-based symmetrical (12E,21E)-N1’,N3’-bis(2-hydroxybenzylidene) isophthalohydrazide , receptor (1) was synthesized and characterized using various spectroscopic technique. The reorganization ability of receptor (1) was evaluated in semi-aqueous medium and shows significant enhancement in fluorescence intensity for Zn (II) ion over various metal ions in CH 3 CN:H 2 O (1:1, v / v ). The 1:2 binding stoichiometry between receptor (1) and Zn (II) ion was established using Job’s plot and the proposed complex structure was calculated by applying Density Functional Theory (DFT) method. The binding constant ( K a ) of receptor (1) with Zn (II) ion was established with the Benesi-Hildebrand plot, Scatchard and Connor’s plot and the values are 1.00 × 10 4  M −1 , 1.05× 10 4  M −1 and 1.05× 10 4  M −1 respectively. The limit of detection ( LOD ) and limit of quantification ( LOQ ) of receptor (1) and Zn (II) ion was 0.292 μM and 0.974 μM respectively. The binding mode was due to photo-induced electron transfer (PET) and the coordination of Zn (II) ion with C = N hydroxyl group of receptor (1). Electrochemical analysis of metal free receptor (1) and with Zn (II) ion also confirmed the formation of complex.