An anionic chromogenic chemosensor based on 4–(4–nitrobenzylideneamine)–2,6–diphenylphenol for selective detection of cyanide in acetonitrile–water mixtures

Abstract

4-(4-Nitrobenzylideneamine)-2,6-diphenylphenol 3a was synthesized and studied as an anionic chromogenic chemosensor. Solutions of 3a in acetonitrile are colorless but turn blue under deprotonation. From the various anions added to the solutions of 3a only CN-, F-, and with less intensity CH 3 COOand H 2 PO 4-, led to colored solutions. With the addition of up to 2.4% (v/v) of water, of all the anions used only CNwas able to act as a base and cause a change in the color of the solution. A model was used to explain the results, based on two 3a:anion stoichiometries, 1:1 and 1:2.

Nitro-Substituted 4-[(Phenylmethylene)imino]phenolates: Solvatochromism and Their Use as Solvatochromic Switches and as Probes for the Investigation of Preferential Solvation in Solvent Mixtures

“…The synthesized compounds have the potential to be applied as probes in the investigation of binary solvent mixtures and other systems, such as surfactants in aqueous medium and the micropolarity of cyclodextrins, besides their possible applications as anionic chromogenic chemosensors. , In addition, the data presented herein indicate the possibility to synthesize programmed perichromic dyes (as shown by dye 3d ) that can be designed with stored information to be read by its solvation shell, which is translated into a sharp change in the optical signal with very subtle changes in the composition of the medium . The authentic solvatochromic switch demonstrated by the behavior of 3d in alcohol/water mixtures is of interest in relation to the synthesis of other systems, aimed at the design of smart materials that undergo changes in their optical properties, which are triggered by alterations in their microenvironment.…”

“…Compound 2c was prepared by means of a procedure described recently. 38 Compound 2d was prepared by a procedure similar to that described for 2b, but using ethanol (5 mL) as the solvent, as well as 2,4-dinitrobenzaldehyde (0.100 g, 0.51 mmol) and 4-amino-2,6diphenylphenol (0.133 g, 0.51 mmol). The precipitate formed after freezing overnight was filtered off under vacuum, washed with iced ethanol, and recrystallized three times from ethanol.…”

“…The motivation for this study came from the results of our previous research involving compounds able to act as chromogenic chemosensors for anions in solution. We studied 4-[[(4-nitrophenyl)methylene]imino]-2,6-diphenylphenol (2c) in acetonitrile and in acetonitrile/water mixtures 38 and discovered that this compound, when deprotonated, colors solutions and that the color changes depend on the percentage of water in the medium. 38 Thus, herein, we describe the UV− vis spectral behavior of 3a−d in pure solvents and potential applications of these compounds as probes to investigate binary solvent mixtures and as solvatochromic switches.…”

“…We studied 4-[[(4-nitrophenyl)methylene]imino]-2,6-diphenylphenol (2c) in acetonitrile and in acetonitrile/water mixtures 38 and discovered that this compound, when deprotonated, colors solutions and that the color changes depend on the percentage of water in the medium. 38 Thus, herein, we describe the UV− vis spectral behavior of 3a−d in pure solvents and potential applications of these compounds as probes to investigate binary solvent mixtures and as solvatochromic switches. The data obtained are discussed on the basis of dye−solvent, dye−dye, and solvent−solvent interactions.…”

Switchable Optical Probes for Simultaneous Targeting of Multiple Anions

“…Considering this fundamental difference, several groups had achieved simultaneous detection of multiple anions merely varying the polarity of the host medium. Some of the recent examples ( 53‐64 ) based on this strategy have been shown in Table …”