Isophthaloyl-Based Selective Fluorescence Receptor for Zn (II) Ion in Semi-Aqueous Medium
作者:N. B. Khadke、A. A. Patil、D. Y. Patil、A. V. Borhade
DOI:10.1007/s10895-019-02385-1
日期:2019.7
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 (Ka) 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.
合成了一种新颖的以异苯二甲酰基为基础的对称(12E,21E)-N1’,N3’-双(2-羟基苯亚甲基)异苯二甲肼受体(1),并通过各种光谱技术对其进行了表征。受体(1)在半水介质中的重组能力进行了评估,显示出在CH3CN:H2O(1:1,v/v)溶液中,对Zn(II)离子的荧光强度显著增强,相较于其他金属离子。使用Job图确定了受体(1)与Zn(II)离子之间的1:2结合化学计量比,并通过应用密度泛函理论(DFT)方法计算了拟合的复合物结构。利用Benesi-Hildebrand图、Scatchard图和Connor图确立了受体(1)与Zn(II)离子的结合常数(Ka),其值分别为1.00×10^4 M−1、1.05×10^4 M−1和1.05×10^4 M−1。受体(1)与Zn(II)离子的检测限(LOD)和定量限(LOQ)分别为0.292 μM和0.974 μM。结合方式是由于光激发电子转移(PET)及Zn(II)离子与受体(1)中的C=N羟基的配位。金属自由受体(1)与Zn(II)离子的电化学分析也确认了复合物的形成。