Electrochemical Bromide Sensing with a Halogen Bonding [2]Rotaxane

Abstract

The selective electrochemical sensing of heavy halides, such as bromide, over more charge‐dense counterparts, like chloride, using mechanically‐interlocked structures remains a formidable challenge. Using the active‐metal templation methodology, the first redox‐active ferrocene‐appended rotaxane containing an all‐halogen bonding anion binding cavity was synthesised. 1H NMR binding studies in aqueous–organic solvent media demonstrated a marked recognition bias for heavy halides, facilitating the selective redox sensing of bromide over chloride to be demonstrated for the very first time with an interlocked host molecule.

Enhanced voltammetric anion sensing at halogen and hydrogen bonding ferrocenyl SAMs

“…[2][3][4] More recently, halogen bonding (XB) has emerged as a potent noncovalent interaction to drive anion recognition, often displaying enhanced anion selectivity and binding strength in comparison to HB analogues. 5,6 This has also been exploited in electrochemical anion sensors in solution, [7][8][9][10][11] and, very recently, at receptive interfaces. [12][13][14] The surface-immobilisation of (redox-active) receptors is relevant to the development of real-life relevant sensors, [15][16][17][18] enabling facile sensor reuse, and sensing both under flow and in (aqueous) solvent media in which many synthetic receptors are not natively soluble.…”

Anion templated crystal engineering of halogen bonding tripodal tris(halopyridinium) compounds

“…[1][2][3][4][5] Notably, halogen bond donor groups have been used to prepare strong and selective anion receptors that function in highly competitive media, 6 including pure water. [7][8][9] As well as their use in anion recognition, halogen bond donors 10 have been used in anion binding catalysis [11][12][13] and to template the selfassembly of a range of supramolecular architectures, including helices/helicates, [14][15][16][17] interlocked molecules, [18][19][20][21] and frameworks. 22,23 As well as these architectures, several halogen bonded capsules have been reported.…”

Squaramide—Naphthalimide Conjugates as “Turn-On” Fluorescent Sensors for Bromide Through an Aggregation-Disaggregation Approach

“…Nyokong and co-workers reported the use of GSH-capped quantum dots (QDs) covalently linked to a nickel tetraamino-phthalocyanine complex where the covalent binding of the QDs to the Ni complex induced fluorescence quenching before with introduction of Br– restoring the fluorescence (Adegoke and Nyokong, 2013). Most recently, Beer and co-workers developed a redox-active ferrocene functionalized rotaxane with a halogen bonding anion binding site that was capable of selective Br − sensing over Cl − in the presence of water as measured by 1 H NMR and electrochemical measurements (Lim and Beer, 2019).…”