Organic Iodides Research Articles

Simultaneous Electrochemical Exfoliation and Covalent Functionalization of MoS2 Membrane for Ion Sieving.

Transition metal dichalcogenide membranes exhibit good antiswelling properties but poor water desalination property. Here, a one-step covalent functionalization of MoS2 nanosheets for membrane fabrication is reported, which is accomplished by simultaneous exfoliating and grafting the lithium-ion-intercalated MoS2 in organic iodide water solution. The lithium intercalation amount in MoS2 is optimized so that the quality of the produced 2D nanosheets is improved with homogeneous size distribution. The lamellar MoS2 membranes are tested in reverse osmosis (RO), and the functionalized MoS2 membrane exhibits rejection rates of >90% and >80% for various dyes (Rhodamine B, Crystal Violet, Acid Fuchsin, Methyl Orange, and Evans Blue) and NaCl, respectively. The excellent ion-sieving performance and good water permeability of the functionalized MoS2 membranes are attributed to the suitable channel widths that are tuned by iodoacetamide. Furthermore, the stability of the functionalized MoS2 membranes in NaCl and dye solutions is also confirmed by RO tests. Molecular dynamics simulation shows that water molecules tend to form a single layer between the amide-functionalized MoS2 layers but a double layer between the ethanol-functionalized MoS2 (MoS2 -ethanol) layers, which indicates that a less packed structure of water between the MoS2 -ethanol layers leads to lower hydrodynamic resistance and higher permeation.

Efficient and simultaneous capture of iodine and methyl iodide achieved by a covalent organic framework

Radioactive molecular iodine (I2) and organic iodides, mainly methyl iodide (CH3I), coexist in the off-gas stream of nuclear power plants at low concentrations, whereas few adsorbents can effectively adsorb low-concentration I2 and CH3I simultaneously. Here we demonstrate that the I2 adsorption can occur on various adsorptive sites and be promoted through intermolecular interactions. The CH3I adsorption capacity is positively correlated with the content of strong binding sites but is unrelated to the textural properties of the adsorbent. These insights allow us to design a covalent organic framework to simultaneously capture I2 and CH3I at low concentrations. The developed material, COF-TAPT, combines high crystallinity, a large surface area, and abundant nucleophilic groups and exhibits a record-high static CH3I adsorption capacity (1.53 g·g−1 at 25 °C). In the dynamic mixed-gas adsorption with 150 ppm of I2 and 50 ppm of CH3I, COF-TAPT presents an excellent total iodine capture capacity (1.51 g·g−1), surpassing various benchmark adsorbents. This work deepens the understanding of I2/CH3I adsorption mechanisms, providing guidance for the development of novel adsorbents for related applications.

I2 and CH3I capture in a γ-radiation stable metal-organic framework: CAU-21-ODB

Successful capture of radioactive iodine and organic iodide is one of the primary objectives in spent fuel reprocessing process. Common adsorbent like porous zeolite, activated carbon, etc. are been tested for such sequestration since long back. However, low surface area, poor uptake capacity, poor recyclability and low stability encouraged the scientific community to look for alternative. Use of another kind of porous material known as metal organic framework (MOF) is still under investigation. In this study, I2 & CH3I uptake performance of an aluminium based MOF, CAU-21-ODB has been evaluated. The framework has been synthesized with significantly higher yield and characterized employing PXRD, FTIR, Raman, 27Al MAS-NMR, EDX and XPS spectroscopies. The framework has significant thermal as well as radiation stability, > 1.75 ​MGy gamma energy. It can reversibly adsorb 60 ​wt% I2 and 21 ​wt% CH3I with faster kinetics. Recyclability tests indicate that the material can re-adsorb almost 88% and 85% of the initially adsorbed I2 and CH3I, respectively, even at fourth repetitive cycles. Based on experimental findings, it can be presumed that CAU-21-ODB could be a potential adsorbent for radioactive I2 and CH3I under actual off gas scenario.

Stability and Efficiency Enhancement of Perovskite Solar Cells Using Phenyltriethylammonium Iodide

AbstractControlling the perovskite film surface is key to improving both the stability and photovoltaic performance of perovskite solar cells. In particular, surface defects on the perovskite films, which are fundamental issues, must be passivated. This work presents a 2D organic material phenyltriethylammonium iodide (PTEAI) to passivate a 3D (FAPbI3)1−x(MAPbBr3)x perovskite film surface. PTEAI forms a well‐matched conformal layer on the perovskite film, protecting the film surface from moisture by preventing the escape of organic ions from the film. The N+ cations and I− anions in PTEAI form bonds with the locally charged perovskite surface, reducing the surface defect density as well as the impeding non‐radiative recombination while enhancing carrier lifetimes. These PTEAI features facilitate significant enhancements in both the open‐circuit voltage (VOC) and fill factor (FF) of the perovskite solar cells. As a result, the champion PTEAI‐based perovskite solar cell exhibits the highest power conversion efficiency of 20.2% compared with 18.8% by the pristine device. Additionally, the PTEAI‐treated device retains 92% of its initial efficiency after being stored in ambient air at room temperature and a relative humidity of 40–60% for 500 h without encapsulation.

Switchable, Reagent-Controlled C(sp3)-H Selective Iodination and Acetoxylation of 8-Methylquinolines.

An efficient Pd-catalyzed C(sp3)-H selective iodination of 8-methylquinolines is reported herein for the first time. Because of the versatility of organic iodides, the method offers a facile access to various C8-substituted quinolines. By slightly switching the reaction conditions, an efficient C(sp3)-H acetoxylation of 8-methylquinolines has also been enabled. Both approaches feature mild reaction conditions, good tolerance of functional groups, and a broad substrate scope.

Formation of regulated and unregulated disinfection byproducts during chlorination and chloramination: Roles of dissolved organic matter type, bromide, and iodide

Algal blooms and wastewater effluents can introduce algal organic matter (AOM) and effluent organic matter (EfOM) into surface waters, respectively. In this study, the impact of bromide and iodide on the formation of halogenated disinfection byproducts (DBPs) during chlorination and chloramination from various types of dissolved organic matter (DOM, e.g., natural organic matter (NOM), AOM, and EfOM) were investigated based on the data collected from literature. In general, higher formation of trihalomethanes (THMs) and haloacetic acids (HAAs) was observed in NOM than AOM and EfOM, indicating high reactivities of phenolic moieties with both chlorine and monochloramine. The formation of haloacetaldehydes (HALs), haloacetonitriles (HANs) and haloacetamides (HAMs) was much lower than THMs and HAAs. Increasing initial bromide concentrations increased the formation of THMs, HAAs, HANs, and HAMs, but not HALs. Bromine substitution factor (BSF) values of DBPs formed in chlorination decreased as specific ultraviolet absorbance (SUVA) increased. AOM favored the formation of iodinated THMs (I-THMs) during chloramination using preformed chloramines and chlorination-chloramination processes. Increasing prechlorination time can reduce the I-THM concentrations because of the conversion of iodide to iodate, but this increased the formation of chlorinated and brominated DBPs. In an analogous way, iodine substitution factor (ISF) values of I-THMs formed in chloramination decreased as SUVA values of DOM increased. Compared to chlorination, the formation of noniodinated DBPs is low in chloramination.

Hysteresis‐Free Planar Perovskite Solar Module with 19.1% Efficiency by Interfacial Defects Passivation

In few years, perovskite solar devices have reached high efficiency on lab scale cells. Upscaling to module size, effective perovskite recipe and posttreatment are of paramount importance to the breakthrough of the technology. Herein this work, the development of a low‐temperature planar n–i–p perovskite module (11 cm2 aperture area, 91% geometrical fill factor) is reported on, exploiting the defect passivation strategy to achieve an efficiency of 19.1% (2% losses stabilized) with near‐zero hysteresis, that is the most unsolved issue in the perovskite photovoltaic technology. The I/Br (iodine/bromide) halide ion ratio of the triple‐cation perovskite formulation and deposition procedure are optimized to move from small area to module device and to avoid the detrimental effect of dimethyl sulfoxide (DMSO) solvent. The organic halide salt phenethylammonium iodide (PEAI) is adopted as surface passivation material on module size to suppress perovskite defects. Finally, homogeneous and defect‐free layers from cell to module with only 8% relative efficiency losses, high reproducibility, and optimized interconnections are scaled by laser ablation methods. The homogeneity of the perovskite layers and of the full stack was assessed by optical, morphological, and light beam–induced current (LBIC) mapping characterizations.

Important effects of relative humidity on the formation processes of iodine oxide particles from CH3I photo-oxidation

In this work, laboratory chamber experiments of gas-phase methyl iodide photolysis in the presence of ozone at three relative humidity conditions were performed to study the formation and physico-chemical properties of iodine oxide particles. The obtained results revealed significant morphological changes of iodine oxide particles that were observed to depend on relative humidity. The formed iodine oxide particles under dry conditions were supposed to be agglomerates of fine hygroscopic crystals. On the other hand, a humid atmosphere was observed to favor the formation of isomeric, tetragonal and orthorhombic hygroscopic crystals potentially composed of HIO3 likely formed from progressive hydration of iodine oxide clusters. This process leads to a release of molecular iodine, I2, which may indicate a potential role of I2O4 in the particles’ evolution processes. The obtained results on the iodine oxides’ behavior are important to the nuclear power plant safety industry since many of the organic iodides that may be released during a major nuclear power-plant accident contain radioactive isotopes of iodine that are known to have lethal or toxic impacts on human health.

Efficient organic iodide capture by a mesoporous bimetallic-organic framework

Release of radioactive organic iodide into atmosphere without any treatment will seriously endanger the environment and life safety. However, removal of radioactive organic iodides is challenging due to their extremely low concentration combined with harsh operational conditions such as high humidity and acidic conditions. Here, we report the generation of mesopores from a metal-organic framework, enabling a record adsorption of >2.8 g/g at room temperature and >0.87 g/g at 423 K toward CH3I under dynamic conditions as demonstrated by breakthrough experiments. Even under humid and acidic conditions, its adsorption performance is maintained. The complete removal of CH3I (expressed by retention time) using this material under humid and acidic conditions is as long as 100 min/g, suggesting its potential application in sequestrating radioactive organic iodide. The excellent adsorption performance is mainly due to (1) physical adsorption and (2) the methylation reaction between pyrazole-4-carboxylic acid and CH3I.

An overview on metal Oxide-based materials for iodine capture and storage

• Sources and reactions of various iodine species are summarized. • Metal oxide-based adsorbents’ potential abilities for iodine capture are discussed. • Metal oxides can form stable oxyiodide forms for long-term radioidine storage. • Silver and Bismuth oxides show better performance for iodine capture and storage. • Metalloid oxides are used as low-sintering temperature additives to limit iodine loss during storage. Long-lived 129 I, short-lived 131 I, and organic iodides released from nuclear plants are volatile and harmful to the ecosystem. For operational safety, and sustainable development of nuclear industries, effective means of trapping various iodine radioisotopes are of great concern. Wet scrubbing methods are often combined with adsorbents to entrap radioiodine species effectively, and thus the search for materials with high performance is still needed. Metal oxides are believed to be potential candidates for real applications. In this review, we documented the metal oxide-based materials for volatile radioactive iodine capture, with limitations on operating conditions, adsorption capacities, and long-term immobilization. Advantages, shortcomings of various metal oxides toward iodine capture, and metal oxide additives for a low-sintering temperature of iodide waste forms have been elucidated for helping in the long-term future development of efficient materials for iodine capture and storage.

Iridium-Catalyzed Hydroiodination and Formal Hydroamination of Olefins with N-Iodo Reagents and Molecular Hydrogen: An Umpolung Strategy.

We herein report a convenient method to convert olefins to organic iodides and amines using an Ir/ZhaoPhos catalyst, molecular hydrogen, and an electrophilic iodine(I) reagent. High yields and regioselectivities were obtained under mild conditions. In addition, basic workup with potassium carbonate leads to C-N products. Control experiments and DFT calculations tentatively excluded the pathway involving the in situ formation of HI. Instead, a catalytic cycle involving the hydrogenation of the haliranium ion intermediate was proposed.

On the Speciation of Iodine in Marine Aerosol.

We have compiled and analyzed a comprehensive data set of field observations of iodine speciation in marine aerosol. The soluble iodine content of fine aerosol (PM1) is dominated by soluble organic iodine (SOI; ∼50%) and iodide (∼30%), while the coarse fraction is dominated by iodate (∼50%), with nonnegligible amounts of iodide (∼20%). The SOI fraction shows an equatorial maximum and minima coinciding with the ocean “deserts,” which suggests a link between soluble iodine speciation in aerosol and ocean productivity. Among the major aerosol ions, organic anions and non‐sea‐salt sulfate show positive correlations with SOI in PM1. Alkali cations are positively correlated to iodate and negatively correlated with SOI and iodide in coarse aerosol. These relationships suggest that under acidic conditions iodate is reduced to HOI, which reacts with organic matter to form SOI, a possible source of iodide. In less acidic sea‐salt or dust‐rich coarse aerosols, HOI oxidation to iodate and reaction with organic matter likely compete.

Hybrid Organic Lead Iodides: Role of Organic Cation Structure in Obtaining 1D Chains of Face-Sharing Octahedra vs 2D Perovskites

Hybrid Organic Lead Iodides: Role of Organic Cation Structure in Obtaining 1D Chains of Face-Sharing Octahedra vs 2D Perovskites

2D perovskite or organic material matter? Targeted growth for efficient perovskite solar cells with efficiency exceeding 24%

Defects at the surface and grain boundaries at the interface between perovskite and electron transport layer (ETL) induce severe non-radiative recombination, detrimental to device's performance and stability. Organic materials are often used for surface passivation, but most works ascribed the great passivation ability to the formed two-dimensional (2D) perovskite. Here, we demonstrated that the organic halide salt hexaneammonium iodide (HAI) targets growth at grain boundaries and plays a critical role in suppressing the charge recombination instead of forming quasi-2D or 2D perovskite to passivate the surface defects. Moreover, the HAI invested the perovskite films with superhydrophobicity, enhancing the moisture resistance and preventing the diffusion of Li+ into perovskite films. As a result, boosting the efficiency of PSCs from 22.38% to 24.07% (certified efficiency of 23.59%) with a voltage deficit of 0.35 V. The surface treatment also enhances the operational stability of perovskite solar cells (PSCs), unencapsulated devices maintain 81.4% of their initial efficiency for 200 h under continuous light irradiation in the N2 atmosphere.

Construction of diverse C–S/C–Se bonds via nickel catalyzed reductive coupling employing thiosulfonates and a selenosulfonate under mild conditions

A nickel-catalyzed reductive cross coupling between organic iodides and thiosulfonates and a selenosulfonate under mild conditions is disclosed.

Highly efficient synthesis of diselenides and ditellurides catalyzed by polyoxomolybdate-based copper

A polyoxomolybdate-based copper-catalyzed synthesis of diselenides and ditellurides from organic iodides and elemental selenium or tellurium in moderate to excellent yields is developed.

Stable organic lead iodides with three-dimensional crystallographic and electronic structures showing high photoresponse

3D lead iodide perovskite analogs display both high stability and quasi-isotropic photoresponse, consistent with both 3D crystallographic and electronic structures.

Photoredox Activation of Organozinc Reagents: Barbier-Type Reaction of Alkyl Halides with α-(Trifluoromethyl)styrenes.

Organozinc reagents may be activated under blue light irradiation using an organic photocatalyst to generate alkyl radicals. The radicals are trapped by α-(trifluoromethyl)styrenes leading to gem-difluorinated products after elimination of fluoride. The reaction can be conveniently performed under Barbier conditions starting from organic iodides and bromides and elemental zinc.

Single‐Component White‐Light Emitters with Excellent Color Rendering Indexes and High Photoluminescence Quantum Efficiencies

AbstractBroadband white‐light emissions from low‐dimensional organic metal halides have received great attention for applications in energy‐efficient lighting and displays. However, the simultaneous realization of excellent color rendering indexes (CRIs) and high photoluminescence quantum efficiencies (PLQEs) in single‐component white‐light emitters remains a great challenge. Here, a unique 0D organic copper iodide (TPA)CuI2 (TPA = tetrapropylammonium) is developed, in which the edge‐sharing double trigonal planar [Cu2I4]2− dimers are surrounded by the organic cations TPA+, forming core/shell structures at the molecular level. These organic copper iodide single crystals exhibit a dual‐band white‐light emission covering the entire visible spectrum with a high PLQE of 84.4% and an excellent CRI of 91.3. In addition, (TPA)CuI2 nanocrystals are successfully synthesized and exhibit optical properties similar to those of the single‐crystal counterparts. Detailed photophysical studies reveal that the dual‐band emission originates from two self‐trapped emitting states in [Cu2I4]2− dimers, whose populations are strongly dependent on the temperature. The promising applications of (TPA)CuI2 as efficient and high CRI phosphors are demonstrated by a white‐light light‐emitting diode with a Commission Internationale de l'Eclairage coordinate of (0.31, 0.33).

Bismuth(III) Iodide Complexes with 1-Ethyl-4-Dimethylaminopyridinium: Structure, Thermal Stability, and Optical Properties

Polynuclear bismuth(III) iodide complexes with 1-ethyl-4-dimethylaminopyridinium (1-EtDMAP)4[Bi8I28] (1) and (1-EtDMAP)BiI4 (2) have been obtained by the reactions of bismuth(III) iodide with an organic iodide salt cations in organic solvents and characterized by X-ray diffraction. The optical properties and thermal stability of the obtained compounds have been studied.