A Pyrazolo Imine‐based Colorimetric and Turn‐on Fluorescent Sensor Probe for Determination of Hg²⁺ Ion and its Application in Test Paper Strips

Abstract

In this work, we synthesized diethylamino substituted pyrazolo imine (3) fluorescent probe for recognition of Hg2+ion.The sensor probe 3 can detect Hg2+ by colorimetric method, and there is a 10‐fold enhancement in fluorescence response. When the fluorescent probe bound with Hg2+ ion, turn‐on fluorescence was observed via the coordination. Probe 3 has an excellent selectivity toward Hg2+ in the CH3CN/H2O (8:2, v/v) solution with low limit of detection and high binding association constant of 551 parts per billion (ppb) and 6.6067 × 106 m−1 for 3+Hg2+, respectively. Furthermore, the formation of 3+Hg2+ complex with 1:1 binding mode was evidenced by Job's plot, 1H NMR spectroscopy and Mass analysis. In addition, probe 3 is a feasible option to detect Hg2+ in various sources of water samples. Bio‐imaging experiments have demonstrated that probe 3 can be used to monitor Hg2+ in Escherichia coli bacterial cell. The sensor 3 was also used for paper strip application to detect Hg2+ ion.

A Comprehensive Review on Cu‐Catalysed Aerobic Oxidation of Amines to Imines

“…[101] A fluorescent sensor based on a cross-reactive aliphatic imine receptor has also been investigated recently. [102][103][104][105] It is predicted that MOFs based on imines will be used as chiral catalysts.…”

Research Progress in Mercury Ion Fluorescence Probes Based on Organic Small Molecules

“…席夫碱类探针中的 N、O、S 杂原子也可与 Hg 2 ＋ 配 位 [32] , 用于检测 Hg 2 ＋ [33] . 目前, 已经有许多席夫碱类荧 光探针通过醛 [34] 或酮 [35] 与伯胺的简单且高产率的反应 获得. 席夫碱化合物与金属离子配位后发生的"Turn On"型荧光响应, 常通过抑制 C＝N 异构化获得 [36] .…”

A high-performance fluorescent and ratiometric colorimetric detection of Cu2+ in practice

“…[14][15][16] The results suggest that there are different ways to improve the optical activity of these organic sensors with superior sensing performance, i.e., extending the p-conjugated length, introducing push and pull electronic structure, strengthening molecular planarity, modifying donor and acceptor, or optimizing bridging groups. 17,18 It is well known that Cu 2+ , a vital of trace metal element in biological systems, plays a key role in human and biological systems. 19,20 However, more or less Cu 2+ in the body will lead to a series of diseases, such as Alzheimer's disease, Parkinson's disease, neutropenia, Wilson's disease, myelopathy, and Menkes syndrome.…”

“…14–16 The results suggest that there are different ways to improve the optical activity of these organic sensors with superior sensing performance, i.e ., extending the π-conjugated length, introducing push and pull electronic structure, strengthening molecular planarity, modifying donor and acceptor, or optimizing bridging groups. 17,18…”