Chemosensors based on N-heterocyclic dyes: advances in sensing highly toxic ions such as CN⁻ and Hg²⁺

Abstract

This review considers the most recent advances in sensing highly toxic ions such as CN− and Hg2+. Specifically, probes bearing N-heterocyclic compounds for their proven versatility for applications in the development of chemosensors are analyzed.

Ecological and Economic Efforts in the Development of Molecular Sensors for the Optical Detection of Cyanide Ions

“…Notably, using 1-pyrenecarboxaldehyde as the starting material leads to probes with the best environmental (energy, RME, SGA, and NTC) and economic (PRMC, NTC, and energy) performance of the probes. In contrast, other pyrene-based probes exhibited higher PRMC and energy values (19) and even NTC (20). However, significant improvements need to be made regarding the solubility and inorganic CN À speciation of this family of probes.…”

“…During the last decade, many molecular probes have been developed to detect cyanide based on nucleophilic attack reactions on an electrophilic center of the recognizing unit of the probe. [19,20,[23][24][25] To reduce the number to a manageable quantity, we selected the molecular probe to be analyzed using the following criteria: organic-based probes, small (250-700 uma), good sensitivity, broad research on the fluorophore (accounting for different receptors) and recently published (2011-present).…”

“…In this respect, organic chemistry can provide countless prospects for designing new cyanide sensors, and many complete and diverse reviews about this topic have been published recently. [14][15][16][17][18][19][20] Notably, molecular probes for cyanide have recently attracted much attention in unconventional computing systems because programable logic devices have been constructed for changing encrypted information into optical signals. [21,22] To the best of our knowledge, none of these works have contemplated the economic and ecological implications of this research.…”

“…Apropos CN À sensing, the nucleophilic addition reaction occurs on an azomethine, carbonyl, iminium, or πdeficient alkene electron-withdrawing group (EWG), whereas in its recognition as a base, deprotonating from phenols, hydrazones, or NH-heterocycles occurs (Figure 1a). [14][15][16][17][18][19][20] This contribution will challenge the environmental and economic efforts of cyanide sensing research by discussing five families of organic probes based on small molecules and includes sensing performance, sustainability features, and typical applications. According to the structural group of the respective probe family, we divide them into the following groups: triphenylamine (TPA), boron dipyrrolomethane (BODI-PY), coumarin, pyrene, and pyrazolo [1,5-a]pyrimidine (PP) derivatives (Figure 1b).…”

Influence of Steric Effect on the Pseudo-Multicomponent Synthesis of N-Aroylmethyl-4-Arylimidazoles

“…The imidazole core is one of the most common among nitrogen-containing pharmaceuticals [8] and has been found to exhibit anti-inflammatory [9], antifungal [10], and antitumor activity [11], among other effects (Figure 1). Moreover, it presents applications in catalysis [12], materials science [13], agrochemicals [14], and chemosensors [15]. Thus, the methods for imidazole synthesis are extensive and can be classified in three general ways: (i) cyclocondensation reactions (the most usual), (ii) a scaffold approach, and (iii) multicomponent reactions (MCRs) [2,7,[16][17][18][19][20][21][22].…”