Showing papers on "Iodide published in 2012"
TL;DR: In this paper, high blue fluorescent graphitic carbon nitride quantum dots (g-CNQDs) were synthesized by a simple microwave mediated method from formamide (HCONH2) and the fluorescence emission was found to be strongly dependent on solvent, pH, and excitation wavelengths; the life time of the emission decreases with increasing polarity of the solvent.
Abstract: Highly blue fluorescent graphitic carbon nitride quantum dots (g-CNQDs) were synthesized by a simple microwave mediated method from formamide (HCONH2). The fluorescence emission of g-CNQDs is found to be strongly dependent on solvent, pH as well as on excitation wavelengths; the life time of the emission decreases with increasing polarity of the solvent. These quantum dots are highly sensitive and selective florescent probes for mercuric ions in aqueous media due to the “superquenching” of fluorescence. The complex formation of Hg2+ ions with the CNx sheet involving π delocalized electron moieties of the latter, in fact, is responsible for the quenching of fluorescence. The addition of iodide ions abstracts the bound Hg2+ forming HgI2 and gives back the fluorescence characteristic of g-CNQDs. Thus, g-CNQDs can play a dual role for selective and sensitive detection of mercuric ions as well as iodide ions in aqueous media via “ON–OFF–ON” fluorescence response.
384 citations
TL;DR: A new nanocrystalline sensitizer with the chemical formula (CH3CH2NH3)PbI3 is synthesized by reacting ethylammonium iodide with lead iodide, and its crystal structure and photovoltaic property are investigated.
Abstract: A new nanocrystalline sensitizer with the chemical formula (CH3CH2NH3)PbI3 is synthesized by reacting ethylammonium iodide with lead iodide, and its crystal structure and photovoltaic property are investigated. X-ray diffraction analysis confirms orthorhombic crystal phase with a = 8.7419(2) A, b = 8.14745(10) A, and c = 30.3096(6) A, which can be described as 2 H perovskite structure. Ultraviolet photoelectron spectroscopy and UV-visible spectroscopy determine the valence band position at 5.6 eV versus vacuum and the optical bandgap of ca. 2.2 eV. A spin coating of the CH3CH2NH3I and PbI2 mixed solution on a TiO2 film yields ca. 1.8-nm-diameter (CH3CH2NH3)PbI3 dots on the TiO2 surface. The (CH3CH2NH3)PbI3-sensitized solar cell with iodide-based redox electrolyte demonstrates the conversion efficiency of 2.4% under AM 1.5 G one sun (100 mW/cm2) illumination.
245 citations
TL;DR: It is proposed that ammonium iodide plays a dual role to provide iodide and nitrogen atom of the cyano moiety in the cyanation of aromatic boronic acids and boronate esters.
Abstract: The cyanation of aromatic boronic acids, boronate esters, and borate salts was developed under copper-mediated oxidative conditions using ammonium iodide and DMF as the source of nitrogen and carbon atom of the cyano unit, respectively. The procedure was successfully extended to the cyanation of electron-rich benzenes, and regioselective introduction of a cyano group at the arene C–H bonds was also achieved. The observation that the reaction proceeds via a two-step process, initial iodination and then cyanation, led us to propose that ammonium iodide plays a dual role to provide iodide and nitrogen atom of the cyano moiety.
188 citations
TL;DR: 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.
Abstract: 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. 1H NMR and fluorescence spectroscopic titration experiments with a variety of anions in the competitive CD3OD/D2O (9:1) aqueous solvent mixture demonstrated the bromo- and syn...
185 citations
TL;DR: In this article, the effect of iodide ion additives was also studied by using electrochemical techniques, and the results showed that amido-imidazoline derivative inhibited corrosion of steel and the extent of its inhibition was concentration dependent.
160 citations
TL;DR: In this paper, the gold-and palladium-catalysed cross-coupling reactions were investigated on two substrates containing an aryl iodide and an allenoate ester.
Abstract: Two substrates containing an aryl iodide and an allenoate ester were prepared and the gold-induced cycloisomerisation to vinylgold(I) species and their proto-deauration as well as the intramolecular palladium-catalysed cross-coupling reactions were investigated. Switching to catalytic amounts of gold and palladium and stoichiometric amounts of silver did indeed furnish the product of a cycloisomerisation/intramolecular cross-coupling. Control experiments revealed that silver cannot substitute for gold or palladium in these reactions, but a different palladium catalyst in a different oxidation state also afforded the cycloisomerisation/intramolecular cross-coupling products in only slightly reduced yields. By ICP analysis the palladium was shown to contain gold only at the sub-ppm level. This shows how carefully results obtained with such systems have to be interpreted. Then a series of allylic and benzylic o-alkynylbenzoates were investigated in gold- and palladium-catalysed reactions. For esters of benzyl alcohol and cinnamyl alcohol no palladium co-catalyst was needed for the conversion. All reagents were thoroughly checked for palladium traces by ICP analysis in order to thoroughly exclude a gold/palladium co-catalysis. Optimisation of the gold complex, counter ion and solvent showed that gold(I) isonitrile pre-catalysts and silver triflate as activator in dioxane are suitable to convert a number of substrates with aryl, alkyl and even cyclopropyl substituents. Crossover experiments proved an intermolecular allyl transfer.
156 citations
TL;DR: 2-Methoxyphenyl)-1,3-dimethyl-1H-benzoimidazol-3-ium iodide (o-MeO-DMBI-I) can be stored and handled in air for extended periods without degradation and is thus promising for various organic electronic devices.
Abstract: 2-(2-Methoxyphenyl)-1,3-dimethyl-1H-benzoimidazol-3-ium iodide (o-MeO-DMBI-I) was synthesized and employed as a strong n-type dopant for fullerene C(60), a well-known n-channel semiconductor. The coevaporated thin films showed a maximum conductivity of 5.5 S/cm at a doping concentration of 8.0 wt% (14 mol%), which is the highest value reported to date for molecular n-type conductors. o-MeO-DMBI-I can be stored and handled in air for extended periods without degradation and is thus promising for various organic electronic devices.
149 citations
TL;DR: It is concluded that infectious activity is lost following direct contact with the solid-state surface of cuprous compounds, but not ROS or copper ions, and that Cu(2)O adsorbed and denatured more proteins than CuO, which suggests the difference of the inhibitory activity between Cu( 2)O and CuO.
148 citations
TL;DR: The promise and progress of replacing the ubiquitous triiodide/iodide electrolyte with cobalt poly-pyridine complex redox shuttles in dye-sensitized solar cells, DSSCs, are focused on.
Abstract: This article focuses on the promise and progress of replacing the ubiquitous triiodide/iodide electrolyte with cobalt poly-pyridine complex redox shuttles in dye-sensitized solar cells, DSSCs. Issues which require further research will also be presented.
140 citations
TL;DR: This review aims to provide a summary of research into bromide and iodide removal from drinking water sources and compared Halide removal techniques, and areas for future research have been identified.
127 citations
TL;DR: In this paper, the transformation and reaction kinetics of iodide and iodate added to soil in relation to soil properties were investigated, using solid phase fractionation coupled with solution phase speciation (HPLC-ICPMS).
TL;DR: In this paper, the synergistic action caused by iodide ions on the corrosion inhibition of mild steel in 1M H 2 SO 4 by leaves and stem extracts of Sida acuta was studied using weight loss and hydrogen evolution methods at 30-60°C.
TL;DR: The process of free chlorine exposure followed by ammonia addition revealed that the formation of iodo-trihalomethanes (I-THMs), especially iodoform, was greatly reduced by an increase of free chlorine exposure and an increased of the Br(-)/I(-) ratio.
Abstract: The kinetics of iodate formation is a critical factor in mitigation of the formation of potentially toxic and off flavor causing iodoorganic compounds during chlorination. This study demonstrates that the formation of bromine through the oxidation of bromide by chlorine significantly enhances the oxidation of iodide to iodate in a bromide-catalyzed process. The pH-dependent kinetics revealed species specific rate constants of k(HOBr + IO–) = 1.9 × 106 M–1 s–1, k(BrO– + IO–) = 1.8 × 103 M–1 s–1, and k(HOBr + HOI) < 1 M–1 s–1. The kinetics and the yield of iodate formation in natural waters depend mainly on the naturally occurring bromide and the type and concentration of dissolved organic matter (DOM). The process of free chlorine exposure followed by ammonia addition revealed that the formation of iodo-trihalomethanes (I-THMs), especially iodoform, was greatly reduced by an increase of free chlorine exposure and an increase of the Br–/I– ratio. In water from the Great Southern River (with a bromide concen...
TL;DR: In this article, the photocathode of a p-type dye-sensitized solar cell with iodide/triiodide (I−/I3−) or tris(4,4′-bis-tert-butyl-2,2′-bipyridine)cobalt (Co2+/Co3+) as redox mediator, and PMI or PMI-NDI as sensitizer was used as a promising substitute for NiO.
Abstract: CuGaO2 is used here as photocathode in place of NiO for a p-type dye-sensitized solar cell with iodide/triiodide (I−/I3−) or tris(4,4′-bis-tert-butyl-2,2′-bipyridine)cobalt (Co2+/Co3+) as redox mediator, and PMI or PMI-NDI as sensitizer Both photovoltaic characteristics and flat band potentials suggest that CuGaO2 can be viewed as a promising substitute for NiO
TL;DR: The results demonstrated that it is important to examine I-THM formation and speciation at typical Br(-)/I(-) ratios of natural waters, which have often been overlooked in previous investigations, in order to obtain practical and relevant results.
TL;DR: A mechanistic model is formulated in which a 5-iodo-1,2,3-triazole is formed via iodination of a copper(I) triazolide intermediate by the electrophilic triiodide ions (and possibly triethyliodoammonium ions).
Abstract: Mixing copper(II) perchlorate and sodium iodide solutions results in copper(I) species and the electrophilic triiodide ions, which collectively mediate the cycloaddition reaction of organic azide and terminal alkyne to afford 5-iodo-1,4-disubstituted-1,2,3-triazoles. One molar equivalent of an amine additive is required for achieving a full conversion. Excessive addition of the amine compromises the selectivity for 5-iodo-1,2,3-triazole by promoting the formation of 5-proto-1,2,3-triazole. Based on preliminary kinetic and structural evidence, a mechanistic model is formulated in which a 5-iodo-1,2,3-triazole is formed via iodination of a copper(I) triazolide intermediate by the electrophilic triiodide ions (and possibly triethyliodoammonium ions). The experimental evidence explains the higher reactivity of the in situ generated copper(I) species and triiodide ion in the formation of 5-iodo-1,2,3-triazoles than that of the pure forms of copper(I) iodide and iodine.
TL;DR: In this paper, the effect of using a binary iodide salt mixture with different size cations on the efficiency enhancement in dye-sensitized solar cells with polyacrylonitrile (PAN) based gel polymer electrolyte was suggested.
Abstract: Dye-sensitized solar cells based on nano-porous TiO2 photo-anode and quasi-solid polymer (or gel) electrolytes are emerging as low cost alternatives to conventional inorganic photovoltaic devices. Although many attempts have been made in order to improve the relatively low power conversion efficiencies of these solar cells, to our knowledge there are very few reports aimed at using a binary system of two different iodide salts toward efficiency enhancement in these cells. In this paper we report for the first time in detail, the effect of using a binary iodide salt mixture with different size cations on the efficiency enhancement in dye sensitized solar cells with polyacrylonitrile (PAN) based gel polymer electrolyte and suggest a possible mechanism for this enhancement, based on short circuit photocurrent which is directly related to the iodide ion concentration [I-]. The gel electrolyte was made of PAN, ethelene carbonate (EC), Propylene carbonate (PC), salt mixture and I-2. The binary iodide salt mixture consists of potassium iodide (KI) and Tetra propyl ammonium iodide (Pr4NI). Although the gel electrolyte with 100% (w/w) KI exhibited the highest overall ionic conductivity at room temperature, it showed the lowest iodide ion (I-) contribution to conductivity. On the other hand, the electrolyte with 100% (w/w) Pr4NI exhibited the lowest overall ionic conductivity but had the highest iodide ion(I-) contribution. The dye-sensitized solar cells of configuration Glass/FTO/TiO2/N-719 Dye/electrolyte/Pt/FTO/glass were fabricated using the gel electrolytes of different salt ratios and with nanoporous TiO2 electrode sensitized with Ruthenium dye (N719). With identical electrolyte compositions, the solar cell with 100% (w/w) KI showed an efficiency of 4.98% and the cell with 100% (w/w) Pr4NI showed an efficiency of 4.47%. However, the cell with the mixed iodide system, 16.6% (w/w) KI + 83.4%(w/w) Pr4NI showed the highest efficiency of 5.36% with maximum short circuit current density (J(SC)) of 13.79 mA cm(-2), open circuit voltage (V-OC) of 679.10 mV and a fill factor of 57.25%. The variation of efficiency (eta) with iodide ion concentration [I-] follows the same trend as the J(SC) which appears to be governed by the iodide ion conductivity of the gel electrolyte. The dependence of the short circuit photocurrent and the open circuit photovoltage on the cation type generally agrees with reported data for related systems. However, the occurrence of a maximum in the solar cell efficiency and short circuit photocurrent at 16.6% (w/w)10 + 83.4% (w/w) Pr4NI salt composition is an important finding. The efficiency enhancement of about 8% achieved by employing the binary iodide mixture in the gel electrolyte instead of a single iodide salt, could be utilized for achieving efficiency enhancement in many dye sensitized solar cell systems based on polymeric, gel or solvent electrolytes.
TL;DR: In this article, a pH sensitive equilibrium was established for polybenzimidazolium hydroxides in AAEMFC, where an ether group was added to the para-position of the 2-phenyl substituent to improve mesomeric stabilization.
TL;DR: An iodide-mediated epitaxial overgrowth of Rh is reported by using the surfaces of well-defined foreign metal crystals as substrates to direct the Rh surface structures and the new role of iodide in the overgrowth could hold the key to future nanoscale control of this important metal's architecture for use in heterogeneous catalysis.
Abstract: Metal nanocrystals (NCs) comprising rhodium are heterogeneous catalysts for CO oxidation, NO reduction, hydrogenations, electro-oxidations, and hydroformylation reactions. It has been demonstrated that control of structure at the nanoscale can enhance the performance of a heterogeneous metal catalyst, such as Rh, but molecular-level control of NCs comprising this metal is less studied compared to gold, silver, platinum, and palladium. We report an iodide-mediated epitaxial overgrowth of Rh by using the surfaces of well-defined foreign metal crystals as substrates to direct the Rh surface structures. The epigrowth can be accomplished on different sizes, morphologies, and identities of metal substrates. The surface structures of the resulting bimetallic NCs were studied using electron microscopy, and their distinct catalytic behaviors were examined in CO stripping and the electro-oxidation of formic acid. Iodide was found to play a crucial role in the overgrowth mechanism. With the addition of iodide, the R...
TL;DR: Terminal alkynes react with aromatic sulfonyl chlorides in the presence of an iron(II) catalyst and a phosphine ligand to give (E)-β-chlorovinylsulfones with 100% regio- and stereoselectivity.
TL;DR: A series of cobalt complexes with various polypyridyl ligands, where the oxidation potential is tuned from 0.17 to 0.34 V vs. ferrocene, are reported, which are used as one-electron redox mediators in dye sensitized solar cells (DSSCs) together with polymer based cathode resulting in an excellent performance.
Abstract: We report a series of cobalt complexes with various polypyridyl ligands, where the oxidation potential is tuned from 0.17 to 0.34 V vs. ferrocene. The highest occupied molecular orbitals (HOMO) of the cobalt complexes were stabilized by adding electron acceptor groups on pyridyl or replacing pyridyl by pyrazole. These complexes are then used as one-electron redox mediators in dye sensitized solar cells (DSSCs) together with polymer based cathode resulting in an excellent performance. The performance of DSSCs using the molecularly engineered cobalt redox shuttle and poly(3,4-alkylthiophenes) based cathode is better than the triiodide/iodide redox shuttle with platinized cathode. The use of high surface area poly(3,4-propylenedioxythiophene) based nanoporous layers allows higher catalytic activity thus minimizing the electrode–electrolyte interface issues.
TL;DR: The particular sensing mechanism was found to be affinity-induced ratiometric and enhanced fluorescence (abbreviated to AIREF), which has rarely been reported previously and may provide an alternative strategy for devising nanoparticle-based sensors.
Abstract: The recently emerging gold nanoclusters (GNC) are of major importance for both basic science studies and practical applications. Based on its surface-induced fluorescence properties, we investigated the potential use of Au25(SG)18 (GSH: glutathione) as a fluorescent iodide sensor. The current detection limit of 400 nM, which can possibly be further enhanced by optimizing the conditions, and excellent selectivity among 12 types of anion (F−, Cl−, Br−, I−, NO3−, ClO4−, HCO3−, IO3−, SO42−, SO32−, CH3COO− and C6H5O73−) make Au25(SG)18 a good candidate for iodide sensing. Furthermore, our work has revealed the particular sensing mechanism, which was found to be affinity-induced ratiometric and enhanced fluorescence (abbreviated to AIREF), which has rarely been reported previously and may provide an alternative strategy for devising nanoparticle-based sensors.
TL;DR: In this article, the binding constants of Lawsone (2-hydroxy-1,4-naphthoquinone) were analyzed in both water and acetonitrile.
Abstract: Lawsone (2-hydroxy-1,4-naphthoquinone), the essential component of henna, is used as a sensitive colorimetric and electrochemical sensor for anions such as cyanide, acetate, fluoride and dihydrogen phosphate (DHP) in acetonitrile. These anions cause a color change in Lawsone's solution from yellow to orange-red. Other anions, such as chloride, bromide, iodide, perchlorate, do not show a significant change. Cyanide changes the color of Lawsone in water:acetonitrile (95:5) solution significantly while acetate causes a slight color change. On the other hand, hydrogen sulfate anion fades the yellow color of the solution. Job's plots show a 1:1 host:guest complex in acetonitrile for cyanide, acetate and fluorides and 1:2 for DHP. In water/acetonitrile the stoichiometry is 1:1 for host:anion. The binding constants show strong binding with cyanide and acetate in both solvent systems.
TL;DR: A simple and reliable fluorescent DNA logic gate is developed by utilizing graphene oxide as a signal transducer and mercury ions and iodide as mechanical activators.
TL;DR: Polymer supported nanoparticles of copper(I) iodide were used as a new, efficient and recyclable catalyst for the regioselective multicomponent synthesis of 1,4-disubstituted-1H-1,2,3-triazoles from α-halo ketones, sodium azide and terminal alkynes in water as discussed by the authors.
TL;DR: The measurement of the electron lifetime while independently varying free iodine or I3– concentrations, finds the lifetime is correlated with free-iodine concentration and independent of I3- concentration, which supports the hypothesis that electron recombination to the electrolyte occurs predominantly by iodine reduction rather than reduction of triiodide.
Abstract: Electron transfer from TiO2 to iodine/iodide electrolytes proceeds via reduction of either I3– or uncomplexed I2 (free iodine), but which route predominates has not previously been determined. By measurement of the electron lifetime while independently varying free iodine or I3– concentrations, we find the lifetime is correlated with free-iodine concentration and independent of I3– concentration. This trend supports the hypothesis that electron recombination to the electrolyte occurs predominantly by iodine reduction rather than reduction of triiodide.
TL;DR: In this paper, a three-dimensional (3D) porous coordination polymer, [Pb(4-bpdh)(NO3)(H2O)]n (HMTI-1), has been synthesized under microwave-irradiation (MW) of identical reaction mixtures of Pb(II) salt and 2,5-bis (4-pyridyl)-3,4-diaza-2, 4-hexadiene (4bpdH) at different powers.
Abstract: A three-dimensional (3D) porous coordination polymer, [Pb(4-bpdh)(NO3)(H2O)]n (HMTI-1), has been synthesized under microwave-irradiation (MW) of identical reaction mixtures of Pb(II) salt and 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene (4-bpdh) at different powers. The microwave synthesis of HMTI-1 has been compared to its conventional synthesis. It has been found that by using MW synthesis HMTI-1 can be obtained in a much shorter synthesis time with improved yield and physical properties. Compound HMTI-1 is stable up to 300 °C in the static atmosphere of nitrogen and useful for loading and unloading of guests. In this compound, we successfully loaded the porous crystals and nano-HMTI-1 with I2 by suspending them in a solution of I2 in cyclohexane. The delivery of I2 from HMTI-1⊃3I2 performed in ethanol, a nonaromatic solvent, at room temperature was determined by UV/vis spectroscopy. A comparison of adsorption and desorption rates of iodide between nano and bulk compounds was also conducted.
TL;DR: Diarylalkynes are chemo- and stereoselectively hydromagnesiated in high yields at room temperature with an iron species generated in situ from FeCl(2)and EtMgBr, and the resulting alkenylmagnesium compounds are a platform for further functionalization as a one-pot reaction.
Abstract: Diarylalkynes are chemo- and stereoselectively hydromagnesiated in high yields at room temperature with an iron species generated in situ from FeCl2and EtMgBr. Functional groups such as bromide, iodide, amine, phenoxide, and alkene are well tolerated. Under similar conditions, diynes are chemo-, regio-, and stereoselectively hydromagnesiated. The resulting alkenylmagnesium compounds are a platform for further functionalization as a one-pot reaction.
TL;DR: The conduction of iodide ions in quasi-solid-state polymer electrolytes and the performance of dye sensitized solar cells containing such electrolytes can be enhanced by incorporating iodides having appropriate cations, as well as the predominantly ionic behaviour of the electrolytes was established from the dc polarization data.
Abstract: Quasi-solid-state dye-sensitized solar cells have drawn the attention of scientists and technologists as a potential candidate to supplement future energy needs. The conduction of iodide ions in quasi-solid-state polymer electrolytes and the performance of dye sensitized solar cells containing such electrolytes can be enhanced by incorporating iodides having appropriate cations. Gel-type electrolytes, based on PAN host polymers and mixture of salts tetrahexylammonium iodide (Hex4N+I−) and MgI2, were prepared by incorporating ethylene carbonate and propylene carbonate as plasticizers. The salt composition in the binary mixture was varied in order to optimize the performance of solar cells. The electrolyte containing 120% Hex4N+I− with respect to weight of PAN and without MgI2 showed the highest conductivity out of the compositions studied, 2.5 × 10−3 S cm−1 at 25 °C, and a glass transition at −102.4 °C. However, the electrolyte containing 100% Hex4N+I− and 20% MgI2 showed the best solar cell performance highlighting the influence of the cation on the performance of the cell. The predominantly ionic behaviour of the electrolytes was established from the dc polarization data and all the electrolytes exhibit iodide ion transport. Seven different solar cells were fabricated employing different electrolyte compositions. The best cell using the electrolyte with 100% Hex4N+I− and 20% MgI2 with respect to PAN weight showed 3.5% energy conversion efficiency and 8.6 mA cm−2 short circuit current density.
TL;DR: A carbazole-thiosemicarbazone-Hg(2+) ensemble-based fluorogenic probe for detection of iodide in aqueous media is reported and the first fluorescent sensor for iodide anions was constructed based on the displacement approach.
Abstract: A carbazole–thiosemicarbazone–Hg2+ ensemble-based fluorogenic probe for detection of iodide in aqueous media is reported. The first fluorescent sensor for iodide anions was constructed based on the displacement approach. An ‘ensemble’ is able to selectively sense iodide over other anions followed by the release of 9-(butane-1-yl)-9H-carbazole-3,6-dihydrazinecarbothioamide to give a remarkable change of fluorescence turn-on signal at pH 7.4 under aqueous media. The practical use of an ‘ensemble’ was demonstrated by its application to the detection of iodide in the living cells.