A Photoswitchable Triple Chemosensor for Cyanide Anion Based on Dicyanovinyl‐Functionalized Dithienylethene

Abstract

The development of new sensors for the accurate detection of cyanide anion has attracted more and more attention due to their potential applications in environmental and biological systems. Here, two novel near‐infrared (NIR) photochromic compounds 1a and 1b, which were modified by the dicyanovinyl fragment with cyanide recognition function, have been developed. Surprisingly, 1a presented an unprecedented triple sensing performance for cyanide anion (colorimetric‐fluorescent‐colorimetric), which can be utilized as a potential precision sensor for CN– in environmental and biological systems. Although 1b did not show triple detection behavior for CN–, it could recognize CN– and F– synchronously and selectively by naked eyes. Moreover, their NIR photochromic behaviors could be modulated by the cyanide anion. Their sensing mechanism for CN– or F– was confirmed by absorption spectral studies, NMR titration, and DFT calculations.

Isatin as a simple, highly selective and sensitive colorimetric sensor for fluoride anion

“…As isatin 1 is a colored compound,its potential in anion recognition/sensing was first monitored by naked eye experiments. This method of sensing is highly valued due to its low cost and easy detection without the help of any instrument or equipment [29,[42][43][44][45][46]. Interestingly, the addition of one equivalent of Fˉ anion to the solution of isatin 1 resulted in a dramatic color change from pale yellow to violet, clearly visible to the naked eye.…”

“…This diversity of function of the fluoride anion, both the benefits and perniciousness, makes its detection of considerable interest. In this context, organic colorimetric chemosensors are of particular importance due to their simplicity [29,[42][43][44][45][46]. Color changes visible to the naked eye are preliminarily used as signals for detection of anions without any equipment being required.…”

“…However, the synthesis of such chemosensors usually requires expensive reagents, and long or tedious synthetic processes, making them less applicable. Therefore, the development of a cheap, non-corrosive, environment friendly, safe, selective, and sensitive chemosensor remains attractive [42,43].…”

“…Apart from its applications in medicinal chemistry [47], it has been extensively employed as a signaling unit in various receptors [51,52] and some of its derivatives have also been investigated as chemosensors for anion detection [53,54]. Careful analysis of its features reveals that isatin 1 has an acidic NH group and intense color which are prime requirements for a chemosensor [29,[42][43][44][45][46]. The interesting structure combined with our recent interest in isatin-derived compounds [55][56][57][58][59] and in developing chemosensors [6,60] motivated us to investigate the behavior of commercially available isatin as an anion sensor.…”

Aldehyde-substituted acceptor-DTE-acceptor-type dithienylethene as a versatile building block for near-infrared photochromic materials

“…12 Thus, there is a need to develop near-infrared (NIR) photochromic materials which are triggered by visible light for future applications in optoelectronics and photopharmacology. [13][14][15][16] In the past few decades, significant progress has been made in visible-light-controlled photochromic compounds. 17,18 The most commonly used method to achieve visible light switches is to extend the π-conjugation system, [19][20][21] which can reduce the highest occupied molecular orbital and the lowest unoccupied molecular orbital (HOMO-LUMO) energy gap of the ring-opened isomer and hence achieve NIR photochromic activity.…”