Recognition Of Iodide Research Articles

Carbon Dot-Gold Nanoparticles Ensemble for Specific Visual Iodide Recognition

Iodide has long been recognized as an effective shape-directing agent for facilitating the growth of anisotropic noble metal nanostructures. However, little attention has been paid to the specific interaction between iodide and metal nanoparticles. In this study, we demonstrate the selective recognition of iodide in solution by the carbon-dot-gold nanoparticles (Cdot-AuNPs) ensemble. Irregularly-shaped AuNPs were generated through the reduction of HAuCl4 by citrate ions and stabilized by Cdot at ambient temperature. Upon the addition of iodide, the color of the solution changed from blue to red with the growth of AuNPs to semi-spherical nanoparticles, as confirmed by transmission electron microscopy. The selectivity test validated that only iodide could induce this specific visual response, highlighting a novel interaction mechanism between iodide and AuNPs. The recognition of iodide by this Cdot-AuNPs ensemble showed good resistance toward many environmentally relevant metal ions, particularly Ca2+, providing potential for the identification of iodide ions in real samples.

Chalcogen Bonding Ion-Pair Cryptand Host Discrimination of Potassium Halide Salts.

A series of chalcogen, halogen and hydrogen bonding heteroditopic macrobicyclic cryptands are reported and their potassium halide ion-pair recognition properties investigated. Saliently, the co-bound potassium cation was determined to be crucial in switching on the bromide and iodide recognition properties of the respective cryptand receptor. Importantly, the nature of the sigma-hole mediated interaction employed in the anion recognition component is demonstrated to significantly augment the ion-pair binding behaviour, markedly so for the halogen bonding analogue. Most notably the incorporation of a chelating chalcogen bonding donor motif significantly improves the selectivity towards KBr over KI, relative to halogen and hydrogen bonding analogues.

Recent Advances in Luminescent Recognition and Chemosensing of Iodide in Water.

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.

Crystal structures, red-shifted luminescence and iodide-anion recognition properties of four novel D-A type Zn(ii) complexes.

Four D-A type Zn(ii) coordination complexes, [Zn(C29H29N3O2)·(CH3OH)]·(CH3OH) (1), Zn2(C74H90N6O4)·(CH3OH) (2), [Zn(C30H28N4O2)·(CH3OH)]·(CH3OH) (3) and [Zn(C38H44N4O2)·(C2H5OH)]·(C2H5OH) (4), were designed, synthesized, and studied. Their fluorescence properties in the solid state and in THF solution were comprehensively analysed based on their single-crystal structures. The results showed that the red-shift of fluorescence emission from complexes 1 to 4 was successfully achieved via the strategy of enhancing intramolecular charge transfer (ICT) effects by increasing the number of electron-pulling and pushing groups gradually. Meanwhile, because of the fluorescence recognition abilities of these four complexes towards iodide anions in THF, they could be regarded as potential fluorescent sensors for I- in this organic solution in the future.

Macroscopic recognition of iodide by polymer appended calix[4]amidocrown resin

ABSTRACTThe current study reveals the synthesis of polymer appended Calix[4]amidocrown-5 with specific binding affinity for iodide at ppm-level. The low detection limits are observed via UV-vis and fluorescence spectroscopy. The time-dependent solution and solid-state 127I NMR studies with 18.8 and 19 ppm shifts, indicate a strong sensing nature of resin towards iodide ion. A significant reduction in surface area and pore volume with higher thermostability of resin after iodide uptake indicated iodide inclusion in the amidocrown cavity. The mechanism of iodide sensing may be governed by noncovalent interactions of NH and OH protons present in amidocrown and phenyl ring as observed in terms of emission enhancement in fluorescence spectroscopy. The binding affinity and stoichiometric determinations are determined by Benesi-Hildebrand and Jobs plots, respectively.

Quinoxaline based redox relay receptor for iodide ions and its application towards real sample analysis and logic gate function

Quinoxaline based azine derivatives (NN1 and NN2) were synthesized from ninhydrin and sensing studies of the receptors were performed with various cations and anions. NN1 and NN2 showed highly selective colour change from orange/yellow to violet/blue respectively for copper ions. Bathochromic shifts of n-π* band of the receptor to d-d transition band of the Cu2+ complex were observed in both the cases. Since anions do not have any straight effect over the receptors, we tried the relay recognition with the copper-receptor in-situ solution with anions. Interestingly, iodide ions selectively regenerated the receptors. It is inferred from the interference studies that no anions have interference over sensing behaviour of the relay recognition of iodide. The receptors showed good binding constants and micromolar detection limit with 1:2 stoichiometric ratio of copper(II) and 1:4 of iodide ions. The relay recognition was selectively applied to quantify iodide ions in common salt and rock salt.

Silver nanoclusters with enhanced fluorescence and specific ion recognition capability triggered by alcohol solvents: a highly selective fluorimetric strategy for detecting iodide ions in urine.

Alcohol solvents especially isopropanol were demonstrated for the first time to endow silver nanoclusters (AgNCs) in water with dramatically enhanced red fluorescence. More importantly, the specific iodide recognition capability of the AgNCs could thus be obtained towards a highly selective fluorimetric assay for detecting iodide ions in urine.

Corrigendum: Iodide Recognition and Sensing in Water by a Halogen-Bonding Ruthenium(II)-Based Rotaxane.

Corrigendum: Iodide Recognition and Sensing in Water by a Halogen-Bonding Ruthenium(II)-Based Rotaxane.

Iodide Recognition and Sensing in Water by a Halogen-Bonding Ruthenium(II)-Based Rotaxane.

The synthesis and anion‐recognition properties of the first halogen‐bonding rotaxane host to sense anions in water is described. The rotaxane features a halogen‐bonding axle component, which is stoppered with water‐solubilizing permethylated β‐cyclodextrin motifs, and a luminescent tris(bipyridine)ruthenium(II)‐based macrocycle component. 1H NMR anion‐binding titrations in D2O reveal the halogen‐bonding rotaxane to bind iodide with high affinity and with selectively over the smaller halide anions and sulfate. The binding affinity trend was explained through molecular dynamics simulations and free‐energy calculations. Photo‐physical investigations demonstrate the ability of the interlocked halogen‐bonding host to sense iodide in water, through enhancement of the macrocycle component’s RuII metal–ligand charge transfer (MLCT) emission.

Nanohybrid Chemosensor for the Simultaneous Detection of Fluoride and Iodide in Aqueous System and Its Utility in Real Samples

AbstractA nanohybrid chemosensor for specific, selective and simultaneous recognition of iodide and fluoride was prepared through decoration of silver nanoparticles onto Schiff‐Base based organic nanoparticles. The developed chemosensor showed specific recognition ability for this analytes at low concentrations with detection limits at 690 nM for fluoride and 11 nM for iodide in two different regions of DPV profiles. Theoretical calculations based in Density Functional Theory were performed, which supports experimental results by demonstrating the binding selectivity of nanohybrids with I− and F−. The proposed sensor was also used for real sample analysis and results were verified using some standard literature method.

Nanomolar Detection of Iodide in Aqueous Medium Using Organic-Inorganic Hybrid Nanoparticles: Application in Urine Analysis.

Imine-linked pyridine-coupled (ILPC) receptors have been synthesised and characterised. The absorption and fluorescence properties of these receptors have been explored through a combination of experimental and theoretical studies. The ILPC receptors are processed into organic nanoparticles (ONPs) and then decorated with gold nanoparticles (AuNPs) for the selective recognition of iodide. The selective recognition behaviour is authenticated with the changes in fluorescence spectra, low detection limit (1.4 nM) and no interference in aqueous systems. The present investigation represents the first example of nanomolar detection of iodide in aqueous medium using organic-inorganic hybrid nanoparticles (ONPs-AuNPs). The probe has been utilised successfully for the detection of iodide content in urine samples.

Fluorescent organic nanoparticles of dihydropyrimidone derivatives for selective recognition of iodide using a displacement assay: application of the sensors in water and biological fluids.

Fluorescent organic nanoparticles (FON's) derived from dihydropyrimidone derivatives (1-4) were developed and evaluated for their sensor properties. Nano-aggregates of compound 3 and 4 resulted in sensors. Nano-aggregates of compound 3 showed enhancement in the monomer peaks of the pyrene moiety after the addition of mercury. Nano-aggregates of compound 4 resulted in quenching of intensity upon addition of Hg(2+). On the other hand, no sensor activity was recorded for nano-aggregates of compounds 1 and 2. Further, the complex of nano-aggregates of 3 and mercury (3·Hg(2+)) recognised iodide ions by showing quenching in monomer and excimer emission with a detection limit of 0.2 nM in aqueous medium; however the resultant metal complex 4·Hg(2+) does not show any anion sensing activity. Receptor 3·Hg(2+) has a highly sensitive and selective response toward I(-) ions. Therefore, the iodide content of tap water, urine and blood serum is monitored using this sensor and it is found that the sensor can detect a range of iodide in tap water, urine and blood serum. To the best of our knowledge, the system represents the first example of iodide recognition using FONs.

Iodide-induced shuttling of a halogen- and hydrogen-bonding two-station rotaxane.

The first example of utilizing halogen-bonding anion recognition to facilitate molecular motion in an interlocked structure is described. A halogen-bonding and hydrogen-bonding bistable rotaxane is prepared and demonstrated to undergo shuttling of the macrocycle component from the hydrogen-bonding station to the halogen-bonding station upon iodide recognition. In contrast, chloride-anion binding reinforces the macrocycle to reside at the hydrogen-bonding station.

Iodide‐Induced Shuttling of a Halogen‐ and Hydrogen‐Bonding Two‐Station Rotaxane

AbstractThe first example of utilizing halogen‐bonding anion recognition to facilitate molecular motion in an interlocked structure is described. A halogen‐bonding and hydrogen‐bonding bistable rotaxane is prepared and demonstrated to undergo shuttling of the macrocycle component from the hydrogen‐bonding station to the halogen‐bonding station upon iodide recognition. In contrast, chloride‐anion binding reinforces the macrocycle to reside at the hydrogen‐bonding station.

Halotriazolium axle functionalised [2]rotaxanes for anion recognition: investigating the effects of halogen-bond donor and preorganisation.

The anion-templated synthesis of three novel halogen-bonding 5-halo-1,2,3-triazolium axle containing [2]rotaxanes is described, and the effects of altering the nature of the halogen-bond donor atom together with the degree of inter-component preorganisation on the anion-recognition properties of the interlocked host investigated. The ability of the bromotriazolium motif to direct the halide-anion-templated assembly of interpenetrated [2]pseudorotaxanes was studied initially; bromide was found to be the most effective template. As a consequence, bromide anion templation was used to synthesise the first bromotriazolium axle containing [2]rotaxane, the anion-binding properties of which, determined by (1) H NMR spectroscopic titration experiments, revealed enhanced bromide and iodide recognition relative to a hydrogen-bonding protic triazolium rotaxane analogue. Two halogen-bonding [2]rotaxanes with bromo- and iodotriazolium motifs integrated into shortened axles designed to increase inter-component preorganisation were also synthesised. Anion (1) H NMR spectroscopic titration experiments demonstrated that these rotaxanes were able to bind halide anions even more strongly, with the iodotriazolium axle integrated rotaxane capable of recognising halides in aqueous solvent media. Importantly, these observations suggest that a halogen-bonding interlocked host binding domain, in combination with increased inter-component preorganisation, are requisite design features for a potent anion receptor.

Silver nanoplates-based colorimetric iodide recognition and sensing using sodium thiosulfate as a sensitizer

A colorimetric method for the recognition and sensing of iodide ions (I−) has been developed by utilizing the reactions between triangular silver nanoplates (TAg-NPs) and I− in the presence of sodium thiosulfate (Na2S2O3). Specifically, I− together with Na2S2O3 can induce protection of TAg-NPs owing to the formation of insoluble AgI, as confirmed by the high-resolution transmission electron microscopy (HRTEM). In the absence of Na2S2O3, the etching reactions on TAg-NPs were observed not only by I− but also other halides ions. The Na2S2O3 plays as a sensitizer in this system, which improved the selectivity and sensitivity. The desired colorimetric detection can be achieved by measuring the change of the absorption peak wavelength corresponding to localized surface plasmon resonance (LSPR) with UV–vis spectrophotometer or recognized by naked eye observation. The results show that the shift of the maximum absorption wavelength (Δλ) of the TAg-NPs/Na2S2O3/I− mixture was proportional to the concentration of I− in the range 1.0×10−9–1.0×10−6molL−1. Moreover, no other ions besides I− can induce an eye discernible color change as low as 1.0×10−7molL−1. Finally, this method was successfully applied for I− determination in kelp samples.

Boehmite Supported Pyrene Polyamine Systems as Probes for Iodide Recognition

New organic–inorganic fluorescent probes made by attaching the tripodal polyamine (tris(2-aminoethyl))amine (tren), propylamine, or diethylenetriamine functionalized with pyrene as a fluorophore to an γ-aluminum oxohydroxide matrix have been prepared and studied both in solution and supported on the surface of boehmite nanoparticles. Both kinds of systems have been revealed as sensitive and selective fluorescence turn-off chemosensors for iodide in aqueous solution with an estimated detection limit that reaches 36 ppb. The recognition characteristics and photophysical properties of these molecules are essentially preserved when they are grafted to the surface of the particles. Since the nanoparticles are stable over a wide pH window and they can be easily recovered by centrifugation and filtration, these systems present the advantage that can be repeatedly used for the detection of iodide.

Graphene sheet-starch platform based on the groove recognition for the sensitive and highly selective determination of iodide in seafood samples

The functionalization of graphene nanosheets was realized using a simple starch mixture to achieve a highly selective recognition of iodide, thereby surmounting the complicated reactions possibly leading to low yield during functionalization. The groove recognition for starch to iodide, a novel recognition model, was established. The starch-to-graphene nanosheet mass ratio of 3:2 produced an optimal current signal. The recognition and measurement procedures were conducted in different cells, respectively. These procedures improved the selectivity and sensitivity, and overcame the possibility of interference from coexisting ions. Under optimal conditions, the graphene sheet-starch electrode was immersed in a recognition cell at pH 2.0 for 10min, afterward, in a measurement cell at pH 1.0 for quantitative analysis, resulting in the highest current signals obtained. The quantitative electrochemical measurements yielded a mean value of 214.6mg/kg in actual samples of commercially available seafood sample, whereas the spectrophotometric measurements produced a mean value of 226.7mg/kg. If the spectrophotometric value for the seafood sample is accurate, the percentage error for the electrochemical method is only 5.3%. Therefore, the electrochemical method is reliable for qualitative iodide measurements. The groove recognition was highlighted to elucidate the specific selectivity.

The pH-dependent interaction of silver nanoparticles and hydrogen peroxide: A new platform for visual detection of iodide with ultra-sensitivity

Considering the significance and urgency for the recognition and sensing of anions specifically, especially those of biological relevance, herein, a simple and reliable colorimetric iodide sensor that based on pH-dependent interaction of silver nanoparticles (AgNPs) and H2O2 was developed. In acidic medium, AgNPs reacted with H2O2 to produce Ag+ and powerful oxidizing species. The powerful oxidizing species could etch AgNPs seriously. While, iodide acted as an antioxidant could protect AgNPs from oxidation-etching by the powerful oxidizing species. In neutral and alkaline medium, the reaction of AgNPs and H2O2 mainly produce Ag+. The existence of iodide could complex with Ag+, forming AgI, which paved the way for aggregation of AgNPs. Based on the different responses of iodide to these different products of the reaction between H2O2 and AgNPs in solutions with different pH, iodide with concentrations down to 1nM in acidic medium, 6nM in neutral medium, and 100nM in alkaline medium could be detected by naked-eye. More importantly, urinary iodide had been detected successfully. This simple and speedy method, which also exhibited remarkable selectivity and outstanding sensitivity, not only innovated the field of iodide recognition but also opened up a novel insight of the application of AgNPs.

Fluorescent Charge-Assisted Halogen-Bonding Macrocyclic Halo-Imidazolium Receptors for Anion Recognition and Sensing in Aqueous Media

The synthesis and anion binding properties of a new family of fluorescent halogen bonding (XB) macrocyclic halo-imidazolium receptors are described. The receptors contain chloro-, bromo-, and iodo-imidazolium motifs incorporated into a cyclic structure using naphthalene spacer groups. The large size of the iodine atom substituents resulted in the isolation of anti and syn conformers of the iodo-imidazoliophane, whereas the chloro- and bromo-imidazoliophane analogues exhibit solution dynamic conformational behavior. The syn iodo-imidazoliophane isomer forms novel dimeric isostructural XB complexes of 2:2 stoichiometry with bromide and iodide anions in the solid state. Solution phase DOSY NMR experiments indicate iodide recognition takes place via cooperative convergent XB-iodide 1:1 stoichiometric binding in aqueous solvent mixtures. (1)H NMR and fluorescence spectroscopic titration experiments with a variety of anions in the competitive CD(3)OD/D(2)O (9:1) aqueous solvent mixture demonstrated the bromo- and syn iodo-imidazoliophane XB receptors to bind selectively iodide and bromide respectively, and sense these halide anions exclusively via a fluorescence response. The protic-, chloro-, and anti iodo-imidazoliophane receptors proved to be ineffectual anion complexants in this aqueous methanolic solvent mixture. Computational DFT and molecular dynamics simulations corroborate the experimental observations that bromo- and syn iodo-imidazoliophane XB receptors form stable cooperative convergent XB associations with bromide and iodide.