Hg(II)-Mediated Intramolecular Cyclization Reaction in Aqueous Media and Its Application as Hg(II) Selective Indicator

Abstract

The Hg(II)-specific intramolecular cyclization reaction of ethynyl phenols was carried out for the first time in semiaqueous media at ambient temperature. The reaction unit (ethynyl phenol) was coupled with a malononitrile derivative (signal unit), which afforded the chromogenic Hg(II) indicator 7. The reaction of the chromogenic Hg(II) indicator 7 was further optimized in DMSO/water (3:7, v/v) (10 mM PBS buffer, pH = 7.0). Compound 7 displays a color change from blue to pale yellow in the presence of Hg(II).

Tuned Cd2+ Selectivity: Showcase of Electronic and Regio-Effect of π-Extended Di-2-Picolylamine-Substituted Quinoline-Based Tolans

“…These similar values obtained from two different titration methods supported the validity of the constants. In addition, the limit of detection (LOD) for Cd 2+ was calculated using the 3σ method (σ = 1.039, m = 1.97 × 10 7 M −1 ) [7] and found to be 158 nM (Figure S4 in the ESI). To further investigate the binding mode of Cd 2+ with 2b, 1 H NMR titration of 2b (2.0 mM) was performed with Cd 2+ in CD 3 CN (Figure S9 in the ESI).…”

“…Recently, our group recognized the fluorescent dye properties of some tolan derivatives without the help of conjugation with other types of dyes. These tolans can function as switches [3,4], sensors [5][6][7], and β-turn mimics [8] depending on various installed motifs. They also exhibit a range of fluorescence quantum yields.…”

Mercury(II) Chloride

“…8 The use of a malononitrile derivative as an electronwithdrawing group has led to the development of a Hg(II) selective indicator that displays a color change from blue to pale yellow.…”

“…Besides novel mercuration reactions with organic substrates, [3][4][5][6][7] HgCl 2 has been extensively used in a variety of cyclization reactions, forming both carbocycles and heterocycles. [8][9][10] Its use as inorganic thiophile has led to the formation of several new products from organosulfur reactants, especially thiocarbonyl compounds. [11][12][13][14][15][16] Finally, the synthesis of mercury(II) alkynyls, mainly from HgCl 2 , and their use as building blocks for supramolecular structures has been reviewed.…”

Preparation of highly sensitive sensors based on polystyrene microspheres for the detection and removal of Hg2+ ions

“…In many studies, it can be seen that kinds of chemosensors have been developed as fluorescent sensor for detecting Hg 2+ ions. For example, Atta et al reported a specific intramolecular cyclization of Hg 2+ of reaction of ethynyl phenols to act as an Hg 2+ ions indicator. Chen et al reported a new fluorescent chemosensor for double signaling behaviors for Hg 2+ ions and Ag + ions in aqueous solution, which was based on the chromophore of naphthalimide and thioether‐rich crown as receptor.…”