Organic Iodides Research Articles

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.

Uncertainty quantification study on gas phase iodine release from Fukushima Daiichi accident in unit 3

A significant amount of radioactive iodine was release to the environment during the accident in the Fukushima Daiichi nuclear power plant. In this numerical study, we used the IMPAIR 2.2 code to simulate the iodine release during containment venting from the suppression chamber gas space and drywell leakage from unit 3 of the power plant. The IMPAIR code was coupled to the Dakota software and uncertainty quantification study and sensitivity analysis of the simulations was performed. The results indicated that both molecular iodine and organic methyl iodide were formed in the water volumes of the plant, where it was transferred to the gas phase of the modeled structures. The sensitivity analysis indicated that the water pH was the most sensitive parameter on the gaseous iodine formation and release during the venting or leakage periods. Additionally, the water pH was shown to affect the speciation of the gas phase iodine. Overall, the simulations performed in this work showed that iodine volatilized from the contaminated water phase in the suppression chamber and the drywell of Fukushima Daiichi unit 3 have an important contribution to the iodine source term to the environment.

Mixed-Halide Double Perovskite Cs2 AgBiX6 (X=Br, I) with Tunable Optical Properties via Anion Exchange.

Lead‐free double perovskites, A2M+M′3+X6, are considered as promising alternatives to lead‐halide perovskites, in optoelectronics applications. Although iodide (I) and bromide (Br) mixing is a versatile tool for bandgap tuning in lead perovskites, similar mixed I/Br double perovskite films have not been reported in double perovskites, which may be due to the large activation energy for ion migration. In this work, mixed Br/I double perovskites were realized utilizing an anion exchange method starting from Cs2AgBiBr6 solid thin‐films with large grain‐size. The optical and structural properties were studied experimentally and theoretically. Importantly, the halide exchange mechanism was investigated. Hydroiodic acid was the key factor to facilitate the halide exchange reaction, through a dissolution–recrystallization process. In addition, the common organic iodide salts could successfully perform halide‐exchange while retaining high mixed‐halide phase stability and strong light absorption capability.

Highly radiation resistant room temperature organic perovskite halide (FAPbI3) crystal for direct detection of gamma-ray photons down to nano curie activity

We report a simple room temperature gamma (-ray detector with electrical read out made using as-grown highly textured crystals of organic perovskite halide formamidium lead iodide (FAPI) prepared by solution method. The detector uses electronics that measure resistance changes, similar to those used in optical detectors. Although it does not have energy resolution, the detector can be used as a quick tool to detect the presence of -ray in wide energy range, from the 100 to the 1250 keV range, with noise limited sensitivity capable of detecting activity down to 50 nCi. The FAPI detector has a reasonable and has been tested for shelf-life of at least six months. The crystal detector was found to have stability toward long term sustained exposure to -ray making it useful in applications needing such long exposure. Also, a proof of concept has been established toward wearable, low cost, portable solid state gamma ray detectors using paper electronics based halide perovskites.

Near-Infrared Artificial Synapses for Artificial Sensory Neuron System.

The computing based on artificial neuron network is expected to break through the von Neumann bottleneck of traditional computer, and to greatly improve the computing efficiency, displaying a broad prospect in the application of artificial visual system. In the specific structural layout, it is a common method to connect the discrete photodetector with the artificial neuron in series, which enhances the complexity of signal recognition, conversion and storage. In this work, organic small molecule IR-780 iodide is inserted into the memory device as both the charge trapping layer and near-infrared (NIR) photoresponsive film. Through electrical and optical regulation, artificial synaptic functions including short-term plasticity, long-term plasticity, and spike rate dependence are realized. In the established artificial sensory neuron system, NIR optical pulses can significantly improve the spiking rate. Moreover, the spiking neural networks are further constructed by simulation for handwritten digit classification. This research may contribute to the development of light driven neural robots, optical signal encryption, and neural computing.

Finkelstein Reaction in Non-polar Organic Solvents: A Streamlined Synthesis of Organic Iodides

Finkelstein Reaction in Non-polar Organic Solvents: A Streamlined Synthesis of Organic Iodides

In Silico Tuning of the Pore Surface Functionality in Al-MOFs for Trace CH3I Capture.

Aluminum (Al)-based metal–organic frameworks (MOFs) have been shown to have good stability toward γ irradiation, making them promising candidates for durable adsorbents for capturing volatile radioactive nuclides. In this work, we studied a series of existing Al-MOFs to capture trace radioactive organic iodide (ROI) from a gas composition (100 ppm CH3I, 400 ppm CO2, 21% O2, and 78% N2) resembling the off-gas composition from reprocessing the used nuclear fuel using Grand canonical Monte Carlo (GCMC) simulations and density functional theory (DFT) calculations. Based on the results and understanding established from studying the existing Al-MOFs, we proceed by functionalizing the top-performing CAU-11 with different functional groups to propose better MOFs for ROI capture. Our study suggests that extraordinary ROI adsorption and separation capability could be realized by −SO3H functionalization in CAU-11. It was mainly owing to the joint effect of the enhanced pore surface polarity arising from −SO3H functionalization and the μ-OH group of CAU-11.

A DFT study of iodine interaction with nuclear reactor cooling system surfaces under severe accident conditions

A severe nuclear accident can lead to the release of radiotoxic iodine compounds in either aerosol form (e.g. metal iodides or iodine oxides) or gaseous form (e.g. organic iodide as CH3I or inorganic as I2) species. 131I is particularly dangerous because of its possible absorption by the human body especially by the thyroid. Gaseous iodine is mainly formed in the nuclear containment building, is dispersed in the case of outside releases and may contribute in short term to long-distance contamination. Metallic iodide species are mainly formed at high temperature and partly condensed on the walls of the reactor coolant system (RCS), the rest being either deposited on the RCS or transported to the containment building. In this paper, we study theoretically, in severe accidental conditions, the adsorption of the metallic iodides on the surface of the primary circuit which is composed of Fe or Cr oxides. At high coverage, AgI and CdI2 form networks on the surfaces of the RCS whereas at low coverage the molecules are isolated. This study, setting out from the stable adsorbates, investigates the chemical mechanisms leading to the iodine re-vaporization. The formation of I2(g) from adsorbed AgI or CdI2 is thermodynamically and kinetically possible on over-oxidized chromium surfaces. On alternative surfaces, the co-adsorption of an oxidant, OH● issued from the steam radiolysis, is necessary to form I2(g). This study tends to show that delayed releases of gaseous iodine are likely to happen from the deposited iodide.

Efficient Dual-Band White-Light Emission with High Color Rendering from Zero-Dimensional Organic Copper Iodide.

Broad-band white-light emissions from organic-inorganic lead halide hybrids have attracted considerable attention in energy-saving solid-state lighting (SSL) applications. However, the toxicity of lead in these hybrids hinders their commercial prospects, and the low photoluminescence quantum yields (PLQYs) cannot meet the requirements for efficient lighting. Here, we report a highly efficient dual-band white-light emission from organic copper iodide, (C16H36N)CuI2, which exhibits a high PLQY of 54.3% and excellent air stability. The single-crystalline (C16H36N)CuI2 possesses a unique zero-dimensional (0D) structure, in which the isolated [Cu2I4]2- dimers are periodically embedded in the wide band gap organic framework of C16H36N+. This perfect 0D structure can cause significant quantum confinement and strong electron-phonon coupling, which contributes to efficient emissions from self-trapped excitons (STEs). Photophysical studies revealed the presence of two self-trapped emitting states in [Cu2I4]2- dimers, whose populations are highly sensitive to the temperature that governs the molecular environment for [Cu2I4]2- dimers and the thermal activation energy of STEs. An ultraviolet (UV) excited white light-emitting diode fabricated using this single-phase white-light emitter exhibits a high color rendering index (CRI) of 78. The new material provides a promising emitter, having a high PLQY and a high CRI simultaneously, for SSL and display applications.

Iodoral-Induced Iatrogenic Hypothyroidism

Background: Iodine is essential for the formation of thyroid hormones. Therefore, the thyroid gland is generally able to maintain normal hormone synthesis despite changes in iodine availability. When there is an increase in iodide load, the thyroid gland is able to inhibit the formation of organic iodide via the Wolff-Chaikoff effect (WCE). This prevents the formation of large quantities of thyroid hormones, thus preventing hyperthyroidism1. Continued exposure to excess iodine is also overcome by the “escape” phenomenon and hormone synthesis resumes in a normal fashion2. However, some patients may lack this autoregulation and develop hypothyroidism. Clinical Case: An 86-year-old male with a history of subclinical hypothyroidism initially presented to his PCP for evaluation of cognitive decline. Workup revealed a TSH of 10 mcIU/mL (0.34 – 5.6 mcIU/mL), a normal FT4 and a negative TPOAb. It was subsequently revealed that the patient was started on Iodoral 12.5 mg daily, an iodine/potassium iodide supplement, 1 month prior to presentation by a naturopathic doctor. Prior to all this, his TSH had always ranged between 4 – 6 mcIU/mL for many years. It was recommended that he discontinue Iodoral and repeat thyroid labs in the future. Despite this, the patient continued on varying doses of Iodoral supplementation. Repeat labs obtained 8 months later revealed an elevated TSH of 99 mcIU/mL and a low FT4 of 0.43 ng/mL (0.6 – 2.6 ng/mL). Despite these numbers, he was asymptomatic and did not exhibit any overt signs of hypothyroidism. He was referred to Endocrinology and finally stopped taking Iodoral.7 weeks post-discontinuation, his repeat labs showed a resolution of hypothyroidism and return to his baseline subclinical disease with a TSH of 8.2 mcIU/mL and a normal FT4. A urine iodine/creatinine was normal at 244.2 ug/g (35 – 540 ug/g) indicating that there was no residual iodine excess from the Iodoral. Conclusion: As far as we are aware, we present the first reported case of Iodoral-induced iatrogenic hypothyroidism. As with past cases of iodine-induced hypothyroidism, our patient had underlying thyroid disease in subclinical hypothyroidism which could explain why he was unable to escape from the WCE. The half-life of Iodoral is unknown but it is generally understood that the effects of iodide are reversed between 2 to 4 weeks after withdrawal. Our patient did not repeat his thyroid function tests until 7 weeks post-discontinuation but did demonstrate a return to baseline with no other intervention. Reference: 1. Markou K, Georgopoulos N, Kyriazopoulou V, Vagenakis AG. Iodine-Induced hypothyroidism. Thyroid. 2001 May;11(5):501-10. doi: 10.1089/105072501300176462. PMID: 11396709.2. Torti JF, Correa R. Potassium Iodide. 2020 Oct 12. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan–. PMID: 31194460.

Removal of persistent organic contaminants from wastewater using a hybrid electrochemical-granular activated carbon (GAC) system

A three-dimensional (3D) electrochemical flow-through reactor equipped with GAC packed bed, polarized by the electric field, was evaluated for the removal of persistent organic contaminants from real sewage effluent. The performance of the reactor was investigated for 27 consecutive runs at two anodic current densities, i.e., low current density (LCD) of 15 A m−2, and high current density (HCD) of 100 A m−2. In the HCD experiments, the adsorption ability of saturated GAC was increased, mainly due to the increase in the mesoporosity of GAC. A synergy between electrosorption/adsorption on GAC and electrooxidation was observed in terms of the removal of all target pollutants. DEET presented the highest synergy, ranging from 40% to 57%, followed by iopromide (22–46%), carbamazepine (15–34%) and diatrizoate (4–30%). The addition of GAC decreased the concentrations of toxic chlorate and perchlorate by 2-fold and 10-fold, respectively, due to their electrosorption on GAC. Also, 3D electrochemical system yielded lower concentrations of adsorbable organic iodide (AOI) and adsorbable organic chlorine (AOCl). Thus, addition of low amounts of GAC in electrochemical systems may be a low-cost and simple way of minimizing the formation and final effluent concentrations of toxic halogenated byproducts.

From 1D to 3D: Perovskites within the System HSC(NH2)2I/CH3NH3I/PbI2 with Maintenance of the Cubic Closest Packing.

This work describes crystalline phases of the system [HSC(NH2)2]I/(CH3NH3)I/PbI2 and discusses the crystal structures in the context of a common cubic closest packing of organic cations and iodide anions with Pb2+ in all anionic octahedral voids. Ternary boundary phases were (CH3NH3)PbI3 (3D perovskite), [HSC(NH2)2]3PbI5 (1D perovskite), [HSC(NH2)2]PbI3 (NH4CdCl3 type), and [HSC(NH2)2]Pb2I5, with strands of edge-sharing octahedra of the NH4CdCl3 type, which are connected to 2D layers via common corners. Within the system, we identified ribbonlike structures of the general composition [HSC(NH2)2]m+1(CH3NH3)mPbmI4m+1 with m = 2 and 3, representing the transition from 1D to 2D structures. Layered structures with variable thickness were found for the series [HSC(NH2)2](CH3NH3)nPbnI3n+1 with n = 1-3. The color and band gap correlate directly with the pattern of how the PbI6 octahedra are linked. 1D structures are colorless or pale yellow to orange. Layered structures are red to black, depending on the layer thickness. A first laboratory-scale solar cell yielded an efficiency of ∼6% based on the compound with n = 3.

2,3,4,5-Tetraiodopyrrole as a building block for halogen bonding: Formation of supramolecular hybrids with organic iodide salts in solid state

Reactions of tri(n-propyl)ammonium (1) or 1,3,5-trimethylpyridinium (2) iodides with 2,3,4,5-tetraiodopyrrole (TIP) results in formation of hybrids CatI•TIP•xEtOH (X = 0.5 (1) and 0.33 (2), respectively) which feature strong halogen bonding (XB) between I atoms of TIP and iodide anions. DFT calculations reveal that XB energies are up to 4.3 kcal/mol.

Direct Surface Passivation of Perovskite Film by 4-Fluorophenethylammonium Iodide toward Stable and Efficient Perovskite Solar Cells.

Passivating the defective surface of perovskite films is becoming a particularly effective approach to further boost the efficiency and stability of their solar cells. Organic ammonium halide salts are extensively utilized as passivation agents in the form of their corresponding 2D perovskites to construct the 2D/3D perovskite bilayer architecture for superior device performance; however, this bilayer device partly suffers from the postannealing-induced destructiveness to the 3D perovskite bulk and charge transport barrier induced by the quantum confinement existing in the 2D perovskite. Hence, developing direct passivation of the perovskite layer by organic ammonium halides for high-performance devices can well address the above-mentioned issues, which has rarely been explored. Herein, an effective passivation strategy is proposed to directly modify the perovskite surface with an organic halide salt 4-fluorophenethylammonium iodide (F-PEAI) without further postannealing. The F-PEAI passivation largely inhibits the formation of the iodine vacancies and thus dramatically reduces the film defects, resulting in a much slower charge trapping process. Consequently, the F-PEAI-modified device achieves a much higher champion efficiency (21%) than that (19.5%) of the control device, which dominantly results from more efficient suppression of interfacial nonradiative recombination and the subsequent decreased recombination losses. Additionally, the F-PEAI-treated device maintains 90% of its initial efficiency after 720 h of humidity aging owing to the enhanced hydrophobicity and decreased trap states, highlighting good ambient stability. These results provide an effective passivation strategy toward efficient and stable perovskite solar cells.

Functionalized hybrid perovskite nanocrystals with organic ligands showing a stable 3D/2D core/shell structure for display and laser applications

A simple one-pot synthesis of stable red-emitting perovskite nanocrystals involved the addition of Cs-oleate, formamidinium bromide (FABr) and organic ammonium iodide salts (LnI, n = 1–5) to a hot flask containing oleic acid, oleylamine and PbI2.

Dual self-trapped exciton emission of (TBA)2Cu2I4: optical properties and high anti-water stability

We report zero-dimensional organic copper iodide single crystals of (TBA)2Cu2I4 with high anti-water stability, which can be stable in water for 24 hours. Upon photoexcitation, this compound exhibits a cool-white emission.

A nitrogen-rich covalent organic framework for simultaneous dynamic capture of iodine and methyl iodide

<h2>Summary</h2> The capture of radioiodine species during nuclear fuel reprocessing and nuclear accidents is crucial for nuclear safety, environmental protection, and public health. Previously reported emerging materials for iodine uptake cannot outperform commercial zeolites and active carbon under the practical dynamic scenario. Herein, we present a new design philosophy aiming at significantly enhanced specific host-guest interactions and obtain a nitrogen-rich covalent organic framework material by introducing a bipyridine group into the building block for the simultaneous capture of both iodine gas through enhanced electron-pair effect and organic iodide via the methylation reaction. These efforts give rise to not only an ultrahigh uptake capacity of 6.0 g g⁻¹ for iodine gas and a record-high value of 1.45 g g⁻¹ for methyl iodide under static sorption conditions but also, more importantly, a record-high iodine loading capability under dynamic conditions demonstrated from the breakthrough experiments.

Suppressed Lattice Disorder for Large Emission Enhancement and Structural Robustness in Hybrid Lead Iodide Perovskite Discovered by High‐Pressure Isotope Effect

AbstractThe soft nature of organic–inorganic halide perovskites renders their lattice particularly tunable to external stimuli such as pressure, undoubtedly offering an effective way to modify their structure for extraordinary optoelectronic properties. Here, using the methylammonium lead iodide as a representative exploratory platform, it is observed that the pressure‐driven lattice disorder can be significantly suppressed via hydrogen isotope effect, which is crucial for better optical and mechanical properties previously unattainable. By a comprehensive in situ neutron/synchrotron‐based analysis and optical characterizations, a remarkable photoluminescence (PL) enhancement by threefold is convinced in deuterated CD3ND3PbI3, which also shows much greater structural robustness with retainable PL after high peak‐pressure compression–decompression cycle. With the first‐principles calculations, an atomic level understanding of the strong correlation among the organic sublattice and lead iodide octahedral framework and structural photonics is proposed, where the less dynamic CD3ND3+ cations are vital to maintain the long‐range crystalline order through steric and Coulombic interactions. These results also show that CD3ND3PbI3‐based solar cell has comparable photovoltaic performance as CH3NH3PbI3‐based device but exhibits considerably slower degradation behavior, thus representing a paradigm by suggesting isotope‐functionalized perovskite materials for better materials‐by‐design and more stable photovoltaic application.

Memristive Organic Bismuth Iodides for Neuromorphic Computing with High Performance

We report here synthesis of memristive organic bismuth iodide and its application to neuromorphic computing. AxBiyIx+3y (A = organic monovalent cation) thin films are prepared by spin coating, where structural dimensionality and electrical properties are found to depend on composition. The solid solution synthesized by mixing 2 dimensional (2D) composition with 0 dimensional (0D) one exhibits bipolar switching behavior, where electrical conductivity is significantly lowered as compared to the individual 2D and 0D phase. In addition, activation energy for resistive switching is also substantially lowered by mixing the dimensionality. Memristor is coupled with transistor (1t-1r system), which results in the resistance of 60 MΩ for writing and the operating voltage of 0.6 V alongside linear and symmetric weight update and selectivity. This indicates that the organic bismuth iodide is highly promising for large scale neural network. Furthermore, a crossbar array prepared based on the synthesized organic bismuth iodide shows linear and symmetric weight update. Simulation using MNIST (Modified National Institute of Standards and Technology) data set based on single-layer perceptron model confirms that average of accuracy rate of the synthesized organic bismuth iodide in the crossbar array is close to ideal rate accuracy.

Decarboxylative Halogenation of Organic Compounds.

Decarboxylative halogenation, or halodecarboxylation, represents one of the fundamental key methods for the synthesis of ubiquitous organic halides. The method is based on conversion of carboxylic acids to the corresponding organic halides via selective cleavage of a carbon–carbon bond between the skeleton of the molecule and the carboxylic group and the liberation of carbon dioxide. In this review, we discuss and analyze major approaches for the conversion of alkanoic, alkenoic, acetylenic, and (hetero)aromatic acids to the corresponding alkyl, alkenyl, alkynyl, and (hetero)aryl halides. These methods include the preparation of families of valuable organic iodides, bromides, chlorides, and fluorides. The historic and modern methods for halodecarboxylation reactions are broadly discussed, including analysis of their advantages and drawbacks. We critically address the features, reaction selectivity, substrate scopes, and limitations of the approaches. In the available cases, mechanistic details of the reactions are presented, and the generality and uniqueness of the different mechanistic pathways are highlighted. The challenges, opportunities, and future directions in the field of decarboxylative halogenation are provided.