Recent Advances in Luminescent Recognition and Chemosensing of Iodide in Water

Abstract

This Minireview covers the latest developments of chemosensors based on transition-metal receptors and organic fluorophores with specific binding sites for the luminescent detection and recognition of iodide in aqueous media and real samples. In all selected examples within the last decade (made-post 2010), the iodide sensing and recognition is probed by monitoring real-time changes of the fluorescence or phosphorescence properties of the chemosensors. This review highlights effective strategies to iodide sensing from a structural approach where the iodide recognition/sensing process, through supramolecular interactions as coordination bonds, hydrogen bonds, halogen bonds and electrostatic interactions, is transduced into an optical change easily measurable. The selective iodide sensing is an active field of research with global interest due to the importance of iodide in biological, medicinal, industrial, environmental and chemical processes.

Naphthalene‐Coupled Pyridinium Urea Salt in Fluorometric Sensing of Iodide

“…[5c,6] Therefore, the detection and sensing of I À ions is of contemporary interest. [7] The examples in the literature intimate that the receptor for the selective binding of anion essentially requires suitable binding site. [3a-g,i,8] In this context, hydrogen bond donor functionalities like amide, urea, hydroxyl, imidazole À NH etc.…”

“…Moreover, iodide is widely used in the synthesis of various dyes and chemicals where subsequent residual discharge in the environment can cause environmental pollution [5c,6] . Therefore, the detection and sensing of I − ions is of contemporary interest [7] …”

“…Apparently, because of strong basicity, anions form hydrogen bond with such functionalities and alter photophysical properties of the receptor molecules. However, because of lower electronegativity of iodide than other halides and oxo‐anionic species like AcO − , H 2 PO 4 − , HP 2 O 7 3− etc., iodide recognition involving hydrogen‐bonded chemosensors are rare in the literature [5c,7,10] . Moreover, water solvation of the anions makes difficult to recognize anionic species in aqueous medium [9c,11] .…”

Urea-doped carbon dots as fluorescent switches for the selective detection of iodide ions and their mechanistic study

“…Spectro-uorimetry has attracted wide attention due to its advantages of rapid response and high sensitivity. In recent years, many uorescent sensors have been developed for the detection of iodide ions, 10 including benzimidazole derivatives, 11,12 gold (silver) nanoparticle clusters, 13,14 porphyrin derivatives, 15 graphene oxide and graphitic carbon nitride. 16,17 Unfortunately, these uorescent sensors usually either involve complicated organic synthesis or need the help of coordination between iodide and heavy metal ions, which impede their practical applications.…”

Regio and stereochemical probes of iodine interactions in diiodocyclododecanes

“…Herein we aim at investigating the role of organic iodine (any iodine atom bound to carbon in an organic compound) in modulating geometry changes and regio/stereochemical stability when it is incorporated into the cyclododecane framework at the 1,4, 1,5, 1,6, and 1,7 positions. It is worth mentioning that iodide is well‐known in recognition/sensing processes through supramolecular interactions, such as halogen bonding [22], while organic iodine has yet a long way to be explored in this field. Accordingly, state‐of‐the‐art quantum‐chemical calculations within the density functional theory and second‐order perturbation analysis of donor‐acceptor interactions in the natural bond orbitals (NBOs) have been performed.…”