2,4,5-Triaryl imidazole probes for the selective chromo-fluorogenic detection of Cu(II). Prospective use of the Cu(II) complexes for the optical recognition of biothiols

Abstract

a b s t r a c tThe sensing behaviour toward metal cations and biothiols of two 2,4,5-triarylimidazole probes (3a and 3b) is tested in acetonitrile and in acetonitrile-water. In acetonitrile the two probes present charge-transfer absorption bands in the 320-350 nm interval. Among all cations tested only Cu(II) is able to induce bathochromic shifts of the absorption band in the two probes, which is reflected in marked colour changes. Colour modulations are ascribed to the formation of 1:1 Cu(II)-probe complexes in which the cation interacts with the imidazole acceptor heterocycle. Besides, the two probes present intense emission bands (at 404 and 437 nm for 3a and 3b respectively) in acetonitrile that are quenched selectively by Cu(II). Probe 3a is soluble in acetonitrile-water 1:1 (v/v) and Cu(II) also induces bathochromic shifts of the absorption bands. Moreover, the emission bands of probe 3a in this mixed aqueous solutions is quenched in the presence of Cu(II). The potential use of the 1:1 complex formed between 3a and Cu (II) for the chromo-fluorogenic detection of biothiols (GSH, Cys and Hcy) in aqueous environments is also tested. At this respect, addition of GSH, Cys and Hcy to acetonitrile-water 1:1 v/v solutions of 3a-Cu(II) complex induces a hypsochromic shift of the visible band (reflected in a bleaching of the solutions) with a marked emission increase at 470 nm. (M.M.M. Raposo), rmaez@ qim.upv. es (R. Martínez-Máñez).

A Selective and Reversible Fluorescent Probe for Cu2+ and GSH Detection in Aqueous Environments

“…Biothiols are molecules that play a fundamental role in living systems and a key role in a variety of biological processes in the body [9–11] . However, some fluorescent thiol probes were still difficult to distinguish GSH/Cys/Hcy as a result of their similar structure [12,13] . For now, using Cu 2+ complexes as a fluorescent probe may be one of the most promising methods for detection of biothiols [14–18] …”

Lysosome-Targeting Fluorescence Sensor for Sequential Detection and Imaging of Cu2+ and Homocysteine in Living Cells

“… 19 , 20 In recent decades, a mass of fluorescence sensors has been developed to identify Hcy from other amino acids, especially structurally similar mercaptoamino acids such as Cys and GSH 21 − 27 by taking advantage of distinctive redox property of Hcy 21 − 23 or nucleophilic reactions based on −SH and/or −NH 2 of Hcy. 24 − 27 To date, however, only a few sensors can sequentially sense Cu 2+ and Hcy 18 , 28 − 38 that usually operated in a mixed medium of organic solvent and water 18 , 28 , 29 , 31 , 32 , 34 , 35 and suffer from the interference from other analytes ( Table S1 ). 28 − 32 , 34 , 36 , 37 Besides, there are rare sensors available for continuous imaging of Cu 2+ and Hcy in living cells.…”

“…Fluorescence sensors are regarded as the most charming method to real-time monitor and track biological species through combining with the laser confocal imaging technology due to its simplicity, sensitivity, and high temporal and spatial resolution. , In recent decades, a mass of fluorescence sensors has been developed to identify Hcy from other amino acids, especially structurally similar mercaptoamino acids such as Cys and GSH − by taking advantage of distinctive redox property of Hcy − or nucleophilic reactions based on −SH and/or −NH 2 of Hcy. − To date, however, only a few sensors can sequentially sense Cu 2+ and Hcy ,− that usually operated in a mixed medium of organic solvent and water ,,,,,, and suffer from the interference from other analytes (Table S1). − ,,, Besides, there are rare sensors available for continuous imaging of Cu 2+ and Hcy in living cells . Thus, it is still urgently needed to develop bifunctional fluorescence sensors for the simultaneous detection of Cu 2+ and Hcy with high sensitivity and selectivity in a prefect aqueous solution and living cells.…”

Construction of a Quinoline‐based Sequential Functioning Chromogenic Sensor for Copper(II) Ion and Biothiols: Its Application to Test Strips

“…Especially, the sensors for relay sensing of metal ions and biothiols have attracted much attention 31–33 . Unlike the detection methods for biothiols based on covalent interaction accompanying long response time, relay detection methods have been usually studied by utilizing a high affinity between metal ions and thiols with fast response time 34–39 . Hence, we focused on developing a sequential functioning sensor for detecting metal ion like Cu 2+ and biological thiols (GSH, Cys, and Hcy) by using a chromophore.…”