Optical Chemical Sensing of Iodide Ions: A Comprehensive Review for the Synthetic Strategies of Iodide Sensing Probes, Challenges, and Future Aspects

Abstract

Among several anions, iodide (I−) ions play a crucial role in human biological activities. In it's molecular form (I2), iodine is utilized for several industrial applications such as syntheses of medicines, fabric dyes, food additives, solar cell electrolytes, catalysts, and agrochemicals. The excess or deficiency of I− ions in the human body and environmental samples have certain consequences. Therefore, the selective and sensitive detection of I− ions in the human body and environment is vital for monitoring their overall profile. Amongst various analytical techniques for the estimation of I− ions, optical–chemical sensing possesses the merits of high sensitivity, selectivity, and utilizing the least amount of sensing materials. The distinctive aims of this manuscript are (i) To comprehensively review the development of optical chemical sensors (fluorescent & colorimetric) reported between 2001–2021 using organic fluorescent molecules, supramolecular materials, conjugated polymers, and metal‐organic frameworks (MOFs). (ii) To illustrate the design and synthetic strategies to create specific binding and high affinity of I− ions which could help minimize negative consequences associated with its large size and high polarizability. (iii) The challenges associated with sensitivity and selectivity of I− ions in aqueous and real samples. The probable future aspects concerning the optical chemical detection of I− ions have also been discussed in detail.

Halide Complexes of 5,6‐Dicyano‐2,1,3‐Benzoselenadiazole with 1 : 4 Stoichiometry: Cooperativity between Chalcogen and Hydrogen Bonding

“…[5][6][7][8][9][10][11][12][13][14][15][16] One of the most interesting applications of SBIs is ion recognition, sensing, and transport by neutral compounds; and anion recognition and sensing are more challenging than those of cations. [4,[7][8][9][10][11][12][17][18][19]20] Amongst anions, halides [Hal] À (Hal = F, Cl, Br, I) are essentially important for living beings and their environment. [19] Amongst SBIs used for anions recognition and sensing, hydrogen, [21][22][23] halogen [24][25][26][27][28][29][30][31] and chalcogen [26,[29][30][31][32][33][34][35][36][37][38][39][40]…”

“…[4,[7][8][9][10][11][12][17][18][19]20] Amongst anions, halides [Hal] À (Hal = F, Cl, Br, I) are essentially important for living beings and their environment. [19] Amongst SBIs used for anions recognition and sensing, hydrogen, [21][22][23] halogen [24][25][26][27][28][29][30][31] and chalcogen [26,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] bondings (HB, XB and ChB, respectively), are, perhaps, the most important; [29,42] in the case of chalcogens, they embrace also hypervalent derivatives, e. g. EF 5 (E = S, Se, Te). [49] Combination of anion-and cation-receipting moieties in a single scaffold is possible to provide cooperative ion-pair recognition.…”

Do Phenyl Substituents Affect the Properties of Azobenzocrown Derivatives?

“…[13][14][15][16] Optical sensors based on supramolecular approach are getting more and more recognition due to their simplicity in addition to their accuracy and precision. [17][18][19] The modification of the skeleton of macrocycles can lead to compounds bearing different functionalities and interesting properties. Among them are azomacrocyclic compounds with azo moiety as a part of macroring.…”

“…Macrocyclic compounds, such as crown ethers and other, can be used for the preparation of the selective stationary phases for chromatography and separation techniques, [10–12] new and advanced sensing of various types of analytes [13–16] . Optical sensors based on supramolecular approach are getting more and more recognition due to their simplicity in addition to their accuracy and precision [17–19] . The modification of the skeleton of macrocycles can lead to compounds bearing different functionalities and interesting properties.…”

“…Displacement ellipsoids drawn at 50 % probability level. Selected bond lengths (Å) and angles (°): a) C4À O6 1.2415 (17), N1À N2 1.3158 (17), C1À N1 1.3189(18), N2À C13 1.4038(18), C2À O1À C25 117.77(10); b) C4À O6 1.260(10), N1À N2 1.337 (9), C1À N1 1.319(10), N2À C13 1.400(10), C2À O1À C25 117.3(6). For torsions in the ether linkers see TableS7.…”