Switchable Optical Probes for Simultaneous Targeting of Multiple Anions

Abstract

Traditional optical probes primarily work on the concept of one-to-one recognition strategy. Therefore, simultaneous detection of multiple anions is difficult using this kind of sensory systems. Similarly, designing of multiresponsive array-based materials is synthetically challenging as well as difficult to optimize. Thus, researchers across the globe became interested in developing single molecular probes, capable of detecting multiple anions (or anionic biomolecules) by simultaneously activating optically distinguishable output channels. Here, the modes of interaction largely depend on the structural features of the binding sites (cleft size, number of available coordination sites etc.), characteristics of the anions (ionic radius, hydration enthalpy, basicity, coordination number, pk a of corresponding acids etc.) and the microenvironment around the probe molecules (micropolarity, viscosity, dielectric constant etc.) in the host matrix. In this review, we are mostly focusing on the structure-activity relationships of such multiple anions sensing optical probes and their stimuli-responsive properties.

Ppb-level, dual channel sensing of cyanide and bisulfate ions in an aqueous medium: computational rationalization of the ion-dependent ICT mechanism

“…There are two main approaches known for this genre of molecular probes. 3 Sometimes, a single receptor site can bind with multiple analytes and display distinguishable optical signals. The differences in basicity, nucleophilicity, hydration energy etc.…”

Modulation of the Naked‐Eye and Fluorescence Color of a Protonated Boron‐Doped Thiazolothiazole by Anion‐Dependent Hydrogen Bonding

“…As anions are ubiquitous in biological systems and aqueous environments, the development of new anion sensors remains an area of high research interest, in which heterocyclic chromophores play an important part. [3][4][5][6][7] The highly electron-deficient thiazolo [5,4-d]thiazole (TzTz) building block, which is comprised of two 1,3-thiazole units fused at the CÀ C bond, has generated increasing interest in small-molecule and materials chemistry for its highly tunable optoelectronic properties. [8][9][10] Their light-harvesting properties make TzTz-based materials excellent candidates for solar cell applications [11][12][13] and photocatalysis.…”

“…Such colorimetric probes work either by an on‐off fluorescence switch or a chromatic shift of their absorption or emission wavelength as they either bind to or undergo a chemical reaction with the contaminant or biological target of interest. As anions are ubiquitous in biological systems and aqueous environments, the development of new anion sensors remains an area of high research interest, in which heterocyclic chromophores play an important part [3–7] …”

Imidazolium-Modified Bispyrene-Based Fluorescent Aggregates for Discrimination of Multiple Anions in Aqueous Solution

“…Fluorescent sensors have been widely used for detection and discrimination of various analytes as they are termed with high sensitivity, multiple detectable signals, on site and in situ detection. − Compared with the sensors for detection of cations, those for anions are less developed due to the large ionic radius of anions, many types of geometric configurations, and other characteristics of anions. , Most of the reported anion sensors are selective ones for specific anions. Until recently, there are growing reports for sensors distinguishing and identifying different anions. − Anzenbacher et al used biguanides as anion receptors and sensor elements, and developed a three-element sensor array for cross-reactive sensing various anions (halides, carboxylates, and phosphates) through multivalent combination. Moreover, the qualitative and quantitative analysis of anions such as Cl – , AcO – , and PPi were realized by using paper disc method combined with pattern recognition analysis in a mixed solution of DMSO and CHCl 3 .…”