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

N B Khadke; A A Patil; D Y Patil; A V Borhade

doi:10.1007/s10895-019-02385-1

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

J Fluoresc. 2019 Jul;29(4):837-843. doi: 10.1007/s10895-019-02385-1. Epub 2019 Jul 15.

Authors

N B Khadke¹, A A Patil², D Y Patil², A V Borhade³

Affiliations

¹ Science Department, Government Residential Women's Polytechnic College, Latur, 413512, India.
² Department of Applied Science and Mathematics, K. K. W Institute of Engineering Education and Research, Nashik,, 422003, India.
³ Department of Applied Science and Mathematics, K. K. W Institute of Engineering Education and Research, Nashik,, 422003, India. ashokborhade2007@yahoo.co.in.

PMID: 31309389
DOI: 10.1007/s10895-019-02385-1

Abstract

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 CH₃CN:H₂O (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 × 10⁴ M^-1, 1.05× 10⁴ M^-1 and 1.05× 10⁴ 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.

Keywords: Binding constant; DFT; Fluorescent chemosensor; Zn (II) detection.