Form Of Iodide Research Articles

Coupled transformation pathways of iron minerals and natural organic matter related to iodine mobilization in alluvial-lacustrine aquifer

The complex of natural organic matter (NOM) and iron minerals in sediment is the main host and source of groundwater iodine. However, the transformation pathways of the complex remain unclear. The groundwater and sediment from the Hetao Basin were collected in this study to analyze multi-isotopes, NOM molecular characteristics, and iron mineral phases. The results showed that high-iodine groundwater was mainly observed in the discharge area, where biodegradation of NOM, sulfate reduction and methanogenesis occurred. Compared to the shallow clayey sediments, the confined sandy sediments had lower iodine content, a lower fraction of crystalline iron oxides, and a higher fraction of carbonate associated Fe(II) minerals, suggesting that the release of sediment iodine in the aquifer is related to the transformation of sediment Fe(III) hydroxides/oxides. Moreover, the molecular features of high-iodine groundwater NOM and sandy sediment NOM were characterized by a higher proportion of refractory compounds, suggesting that the reductive transformation of sediment Fe(III) hydroxides/oxides is fueled by degradable organic compounds. The microbial Fe-reducing and/or sulfate-reducing processes cause the enrichment of groundwater iodine in the form of iodide via the transformation of iodine species. These findings provide new insights into the genesis of high-iodine groundwater.

Effect of iodine species on biofortification of iodine in cabbage plants cultivated in hydroponic cultures

Iodine is an essential trace element in the human diet because it is involved in the synthesis of thyroid hormones. Iodine deficiency affects over 2.2 billion people worldwide, making it a significant challenge to find plant-based sources of iodine that meet the recommended daily intake of this trace element. In this study, cabbage plants were cultivated in a hydroponic system containing iodine at concentrations ranging from 0.01 to 1.0 mg/L in the form of potassium iodide or potassium iodate. During the experiments, plant physiological parameters, biomass production, and concentration changes of iodine and selected microelements in different plant parts were investigated. In addition, the oxidation state of the accumulated iodine in root samples was determined. Results showed that iodine addition had no effect on photosynthetic efficiency and chlorophyll content. Iodide treatment did not considerably stimulate biomass production but iodate treatment increased it at concentrations less than 0.5 mg/L. Increasing iodine concentrations in the nutrient solutions increased iodine content in all plant parts; however, the iodide treatment was 2–7 times more efficient than the iodate treatment. It was concluded, that iodide addition was more favourable on the target element accumulation, however, it should be highlighted that application of this chemical form in nutrient solution decreased the concetrations of selected micoelement concentration comparing with the control plants. It was established that iodate was reduced to iodide during its uptake in cabbage roots, which means that independently from the oxidation number of iodine (+ 5, − 1) applied in the nutrient solutions, the reduced form of target element was transported to the aerial and edible tissues.

A "Pincer" Type of Acridine-Triazole Fluorescent Dye for Iodine Detection by Both 'Naked-Eye' Colorimetric and Fluorometric Modes.

Iodine, primarily in the form of iodide (I-), is the bioavailable form for the thyroid in the human body. Both deficiency and excess intake of iodide can lead to serious health issues, such as thyroid disease. Selecting iodide ions among anions has been a significant challenge for decades due to interference from other anions. In this study, we designed and synthesized a new pincer-type acridine-triazole fluorescent probe (probe 1) with an acridine ring as a spacer and a triazole as a linking arm attached to two naphthol groups. This probe can selectively recognize iodide ions in a mixed solvent of THF/H2O (v/v, 9/1), changing its color from colorless to light yellow, making it suitable for highly sensitive and selective colorimetric and fluorescent detection in water systems. We also synthesized another molecular tweezer-type acridine-triazole fluorescent probe (probe 2) that exhibits uniform detection characteristics for iodide ions in the acetonitrile system. Interestingly, compared to probe 2, probe 1 can be detected by the naked eye due to its circulation effect, providing a simple method for iodine detection. The detection limit of probe 1 is determined to be 10-8 mol·L-1 by spectrometric titration and isothermal titration calorimetry measurements. The binding stoichiometry between probe 1 and iodide ions is calculated to be 1:1 by these methods, and the binding constant is 2 × 105 mol·L-1.

Phenolic Compounds and Antioxidant Properties of Fermented Beetroot Juices Enriched with Different Additives.

Fermented beetroot juice is a beverage obtained from the fermentation of beetroot, most commonly red beet (Beta vulgaris L. var. conditiva). Nowadays, this product is increasingly recognised as a functional food with potentially beneficial health properties. It has been suggested to have antioxidant, anti-inflammatory, anticancer, antihypertensive, immunomodulatory, and probiotic effects, among others. Moreover, with the increasing popularity of the drink, newer variants are appearing in the food market, obtained by modifying the traditional recipe, adding other raw materials, herbs, and spices. Therefore, the aim of this study was to evaluate and compare the antioxidant potential and phytochemical composition of the selected fermented beetroot juices in different flavour variants available in the Polish food market. The study material consisted of six fermented beetroot juices: traditional, with garlic, with horseradish, with acerola, without salt, and iodized. The obtained results showed that the addition of acerola, horseradish, garlic, salt, and iodine in the form of sodium iodide and potassium iodide influenced the composition and properties of fermented beetroot juice. The most promising product in terms of potentially beneficial health properties related to the prevention of free radical diseases was fermented beetroot juice without salt (FRAP-5663.40 µM Fe (II)/L, ABTS-96.613%, TPC-760.020 mg GAE/L, TFC-221.280 mg RE/L). Iodized fermented beetroot juice had the highest vitamin C content-51.859 mg/100 mL. However, all the products tested were characterised by a significant content of biologically active substances with antioxidant properties and showed a high antioxidant potential. Moreover, all the fermented beetroot juices were rated positively in terms of flavour intensity, sweetness, acidity, colour, and overall acceptability. They can, therefore, be a good source of antioxidants in the daily diet.

The Antioxidant Properties of Selected Varieties of Pumpkin Fortified with Iodine in the Form of Potassium Iodide and Potassium Iodate.

This study aimed to investigate the use of selected pumpkin varieties as carriers of potassium iodide (KI) and potassium iodate (KIO3) at different concentrations (2.3, 0.23, and 0.023 mg/100 g). It was hypothesized that the concentrations and form of iodine fortification in pumpkins affect the antioxidant activity of pumpkins. The results showed a high recovery of the introduced iodine in all pumpkin varieties after drying, as well as high iodine stability during storage, especially for KIO3. However, statistical analysis confirmed a relationship between the forms and concentration of iodine and the ABTS cation radical and the DPPH radical test results. In the systems with iodine concentration at 0.023 and 0.23 mg/100 g, the antioxidant activity did not change. However, for all pumpkin varieties fortified with a KIO3 concentration at 3.9 mg/100 g (2.3 mg/100 g of iodine), a statistically significant decrease in free-radical scavenging was confirmed. Therefore, for maximum effectiveness in pumpkin's free-radical scavenging indices, it is suggested to introduce iodine in the form of KI and KIO3, but in controlled concentrations. However, KIO3 should be added at a maximum amount of 0.39 mg/100 g.

Silver ions immobilized on thiourea/formaldehyde resin for solid phase extraction of iodide ions from aqueous solution

Iodine has been found to have considerable effects on tropospheric photochemistry, which in turn affects climate by lowering ozone's radiative forcing and air quality by lowering extreme O3 concentrations in polluted areas. The majority of the iodine that naturally occurs in the water is in the form of aqueous iodide and iodate. To extract iodide from the aqueous solution, thiourea-formaldehyde resin (TF) was prepared by condensation polymerization and then loaded with Ag(I) ions (Ag-TF). TF resin was characterized by a specific surface area close to 111.3 m2 g−1, and nitrogen and sulphur content of 20.57 and 10.01 mmol g−1, respectively. After calculation of the adsorbed amount of Ag(I) ions, the prepared Ag-TF adsorbent was introduced for the solid phase extraction of iodide anions under various operational parameters of pH (e.g., 1.6 – 10.7), adsorbent dose (e.g., 0.5 – 5.0 g L−1), primary iodide concentrations (e.g., 0.075 – 3.96 mmol L−1), and residence time (e.g., 5 – 400 min), and sonication time (e.g., 5–45 min). The findings revealed that the adsorption of iodide onto as-produced TF adsorbent was matched with the Langmuir model with a prominent loading capacity of 1.26 mmol g−1, under an optimized pH value of 2.7. The study of uptake kinetics investigates the influence of the mode of agitation; comparing more specifically the performance of mechanical agitation with those obtained with ultrasonication (at frequencies of 37 and 80 kHz). The ultra-sonication treatment decreased interestingly the adsorption equilibrium time from 400 min to only 45 min. Overall, the present study illustrates the susceptibility of Ag-TF adsorbent as a promising material for the efficient elimination of I− anions from an aqueous medium.

ПЕРСПЕКТИВА ПРИМЕНЕНИЯ ГИБРИДНОГО ПОРОШКОВОГО МАТЕРИАЛА AgI-SiO2 В СОСТАВЕ ПРОТИВОГРАДОВОГО РАКЕТНОГО ТОПЛИВА

The work proposes new hybrid powder materials as sediment-converting reagents used in geoengineering technologies (technologies for artificial precipitation management). Hybrid powder materials AgI-SiO2 are mesophase mesoporous silicon dioxide with silver iodide. They were obtained through the “Paste Formation” process, which involves constant mixing of an aqueous condensed suspension of silicon dioxide of various types with the sequential addition of silver nitrate and potassium iodide. The characteristic features of the synthesized AgI-SiO2 hybrids were studied using instrumental methods of analysis: structural, textural and rheological parameters. The influence of hybrid powder material AgI-SiO2 (HPs) on the efficiency of anti-hail rocket fuel is shown using the TERRA software system for modeling phase and chemical equilibrium at high temperatures. It is certain that using HPs AgI-SiO2 as part of anti-hail rocket fuel leads to an increase in the amount of condensed phase, including active forms of silver iodide. This active form of AgI is required for the implementation of ice formation processes in the cloud. An increase in the amount of the β-form of AgI in the composition of the initial HPs was shown compared to pure silver iodide using X-ray phase (XRF) analysis and differential scanning calorimetry. It was established that silver iodide in the hybrid has greater thermal stability, as evidenced by the characteristic peaks of crystalline forms. HPs AgI-SiO2 will improve the efficiency of anti-hail rocket fuel by increasing the number of ice formation and condensation centers, because they exhibit several mechanisms of action on atmospheric moisture. The synthesized hybrid powders meet the requirements of the regulatory documents in force in the Russian Federation

Iodine supplementation through its biofortification in Brassica species depending on the type of soil.

Iodine is an essential microelement for humans and its deficiency leads to iodine deficiency disorder (IDD) which is a common problem faced by people in hilly areas. Biofortification of iodine is an option to overcome the IDD problem. Herein, we investigated the iodine uptake and accumulation in the edible portion of vegetables such as Brassica napus (BNP) and Brassica pekinensis (BPK) which were grown on two different soils such as sandy soil (SS) and silty loam soil (SLS) with different concentrations of iodine application (used in sodium iodide form) such as 0ppm, 50ppm, and 100ppm. The concentration of iodine was determined by the oxidation of iodide, and nutrients were examined by double acid digestion. Different concentrations of iodine were noticed in silty loam and sandy soils, roots, and shoots of BNP and BPK, while the concentration follows the order: soils > roots > shoots. Iodine concentrations in the roots of BNP and BPK ranged from 46 to 223.7μg/g which shows a strong correlation with other soil nutrients. Moreover, a large amount of iodine was lost due to the leaching. It is concluded that the biofortification of iodine increases its concentration in Brassica species. This work provides a reference for the iodine biofortification in plant species which will be helpful to control IDD.

Sawdust Amendment in Agricultural and Pasture Soils Can Reduce Iodine Losses

Iodine loss is common in the soil of hilly regions due to higher precipitation rates and steeper slopes. Iodine deficiency in soil reduces iodine’s bioavailability to fruits and vegetables and consequently may contribute to health complications. However, the iodine retention of soils after the addition of selected organic and inorganic amendments has not been studied. Therefore, a study was carried out to investigate iodine loss during surface runoff. For this purpose, a soil amendment (namely, sawdust, charcoal, wood ash, lime or gypsum) was applied separately to pasture and agricultural soils under natural rainfall conditions. The soil was fertigated with iodine in the form of potassium iodide (KI) at the rate of 200 ppm. Surface runoff was related to soil properties. Results showed that iodine content in surface runoff was linearly related with soil pH (R2 = 0.89, p < 0.05) and inversely related with soil organic carbon (R2 = −0.76, p < 0.05). Soils amended with sawdust had significantly reduced iodine content in runoff. A higher amount of iodine was lost via surface runoff from soil after inorganic amendment. Soil amendments were varied for iodine retention in soil in the order of sawdust > charcoal > wood ash > lime > gypsum. The study results indicated that organic amendments, especially sawdust, improved soil properties and increased the iodine retention capacity of soils.

Reduced Open‐Circuit Voltage Loss of Perovskite Solar Cells via Forming p/p+ Homojunction and Interface Electric Field on the Surfaces of Perovskite Film

AbstractThe severe nonradiative recombination losses limit the further improvement of open‐circuit voltage (Voc) and power conversion efficiency (PCE) of perovskite solar cells (PVSCs). In this work, the 4,4′‐cyclohexylidenebis [N,N‐bis(4‐methylphenyl) benzene amine] is dissolved into the antisolvent to prepare perovskite films, which reduces defects, improves the crystallinity, and induces a p/p+ homojunction on the top surface of perovskite film. Besides, the 2‐thiophenemethylammonium iodide and 2‐thiophenethylammonium iodide form interface electric field and passivate defects on the bottom surface of perovskite film. The p/p+ homojunction and interface electric field enhance the charges’ separation and transportation efficiencies in the bulk perovskite film and at the perovskite/charge transport layer interfaces, which effectively reduces nonradiative recombination losses and Voc loss of PVSCs. Consequently, low Voc loss of 0.348 V is realized, resulting in the increase in Voc from 1.082 to 1.172 V and PCE from19.15% to 23.44%. The optimized PVSCs without encapsulation maintain 88.23% of the original PCE after exposing in the air for 1500 h. This work provides a strategy to reduce the nonradiative recombination losses and Voc loss by forming p/p+ homojunction and interface electric field on the surfaces of perovskite film, which advances the development of high‐performance PVSCs.

Microplastics as vectors of radioiodine in the marine environment: A study on sorption and interaction mechanism

Radioiodine is one of the long-lived fission products and also an important radionuclide released during nuclear accidents, which generates interest in its environmental fate. Its sorption has been studied in a wide range of materials, but no equivalent study exists for microplastics, an emerging environmental vector. Weathering and biofilm formation on microplastics can enhance radioiodine sorption. For the first time, we're reporting how radioiodine interacts with different types of polyethylene derived microplastics (pristine, irradiated, and biofilm developed microplastics). This study revealed that exposure to radiation and the marine environment significantly alters the physico-chemical properties of microplastics. In particular, in marine-exposed samples, a signature of biofilm development was detected. Speciation study indicates that iodine exists in the iodide form in the studied marine environment. The study revealed that, iodide ions attach to biofilm-developed microplastics via electrostatic, ion-dipole, pore filling, and van der Waals interactions. Pore filling, ion-dipole, and van der Waals interactions may cause iodide binding to irradiated microplastics, whereas pore-filling and van der Waals interactions cause iodide binding to pristine microplastics. The distribution coefficient (Kd) of iodine on microplastics is positively correlated with biofilm biomass, which signifies the role of biofilm in radioiodine uptake. The Kd indicates microplastics are potential iodide accumulators and could be a possible vector in the marine system.

Local environment of iodine dissolved as iodate in high-pressure aluminoborosilicate glasses: A I K-edge x-ray absorption spectroscopic study.

The use of high-pressure synthesis conditions to produce I-bearing aluminoborosilicate represents a promising issue for the immobilization of 129I radioisotope. Furthermore, iodine appears to be more solubilized in glasses under its iodate (I5+) form rather than its iodide (I-) form. Currently, the local atomic environment for iodine is poorly constrained for I- and virtually unknown for I5+ or I7+. We used I K-edge x-ray absorption spectroscopy conducted at 20K for determining the local atomic environment of iodine dissolved as I-, I5+, and I7+ in a series of aluminoborosilicate glasses. We determined that I- is surrounded by either Na+ or Ca2+ in agreement with previous studies. The signal collected from EXAFS reveals that I5+ is surrounded invariably by three oxygen atoms forming an IO3 - cluster charge compensated by Na+ and/or Ca2+. The I-O distance in iodate dissolved in glass is comparable to the I-O distance in crystalline compounds at ∼1.8 Å. The distance to the second nearest neighbor (Na+ or Ca2+) is also constant at ∼3.2 Å. This derived distance is identical to the distance between I- and Na+ or Ca2+ in the case of iodide local environment. For one sample containing iodate and periodate, the distinction between the local environment of I5+ and I7+ could not be made, suggesting that both environments have comparable EXAFS signals.

Treatment of Off-Gas Emissions: Kinetics of Silver Mordenite Catalyzed Methyl Iodide Decomposition

Methyl iodide, a common methylation intermediate used in the production of pesticides and pharmaceuticals, is characterized by both acute and chronic toxicity. In the nuclear industry, some of the radio-iodine release occurs in the form of methyl iodide, exacerbating the hazard posed by the chemical. Sorbents containing silver, particularly silver mordenites, have been preferentially investigated for capturing radio-iodine emissions including those of methyl iodide. Literature reports suggest that methyl iodide is catalytically decomposed by silver mordenite into diatomic iodine and hydrocarbons/hydrocarbon derivatives. Continuous column studies utilizing silver mordenite pellets have experienced difficulties obtaining consistent results within a reasonable time when dealing with air streams containing organoiodides at low (∼100 ppb) concentrations. An alternate approach based on utilizing a thin coating of reduced silver mordenite on an inert honeycomb cordierite matrix is described in the present study. This dynamic sorption study was conducted at 170°C with air streams containing methyl iodide at 110-140 ppb concentrations in absence of moisture. The reduction in the silver mordenite mass needed to conduct the investigations resulted in reduced runtimes and successful quantification of the catalytic decomposition of methyl iodide. Kinetics of this decomposition was determined by varying gas residence time and monitoring the methyl iodide conversion. Data analysis using the integral method revealed the reaction rate had a likely first order dependence on methyl iodide concentration with a rate constant of 0.1202 L/g sorbent/s at the operating temperature. Control experiments revealed that sodium mordenite did not exhibit a similar catalytic decomposition behavior.

Role of alkalis on the incorporation of iodine in simple borosilicate glasses

To understand the influence of alkali elements on the incorporation mechanisms and incorporation limit of iodine in borosilicate glasses used for nuclear waste immobilization, series of model glasses with different alkali contents (22 or 35 mol% Na2O, or 22 mol% of a mixture of alkalis: Na substituted by Li, K and Cs) were loaded with iodine (from 1 000 to 10 000 ppm at. under the form of iodide) at 1100 °C. When the incorporation limit of iodine was reached, alkali iodide crystals were observed (e.g., NaI). For oversaturated samples containing two alkalis, iodide crystals were analyzed and it was found that crystals are enriched in the heavier one of the two relative to bulk composition. Crystal-free glasses were studied by Electron Probe Micro-Analysis to measure the incorporation limit of iodine. A complex variation of incorporation limit was found. Initial substitution of Na by other alkalis (<50%) leads to a decrease in I incorporation limit, this decrease being smallest for Li and largest for Cs. For substitution >50%, only the potassium-bearing system could be studied. In this case, the incorporation limit was non-linear and passed through a minimum for a substitution of ∼75%. Glass structure was determined by X-Ray absorption spectroscopy and Nuclear Magnetic Resonance, providing evidence for local I environments rich in alkalis. It is concluded that high alkali content and high concentrations of Na2O are particularly favorable for iodine incorporation.

The influence of iodide on glass transition temperature of high‐pressure nuclear waste glasses

AbstractThe glass transition temperature (Tg) is a key parameter to investigate for application in nuclear waste immobilization in borosilicate glasses. Tg for several glasses containing iodine (I) has been measured in order to determine the I effect on Tg. Two series of glass composition (ISG and NH) containing up to 2.5 mol% I and synthesized under high pressure (0.5 to 1.5 GPa) have been investigated using differential scanning calorimetry (DSC). The I local environment in glasses has been determined using X‐ray photoelectron spectroscopy and revealed that I is dissolved under its iodide form (I−). Results show that Tg is decreased with the I addition in the glass in agreement with previous results. We also observed that this Tg decrease is a strong function of glass composition. For NH, 2.5 mol% I induces a decrease of 24°C in Tg, whereas for ISG, 1.2 mol% decreases the Tg by 64°C. We interpret this difference as the result of the I dissolution mechanism and its effect on the polymerization of the boron network. The I dissolution in ISG is accompanied by a depolymerization of the boron network, whereas it is the opposite in NH. Although ISG corresponds to a standardized glass, for the particular case of I immobilization it appears less adequate than NH considering that the decrease in Tg for NH is small in comparison to ISG.

Iodine Redistribution During Trauma, Sepsis, and Hibernation: An Evolutionarily Conserved Response to Severe Stress.

Objective:We performed these studies to learn how iodine in the form of free iodide behaves during stress.Design:Prospective observational trial using samples obtained from human trauma patients and retrospective observational study using remnant samples from human sepsis patients and arctic ground squirrels. Preclinical interventional study using hind-limb ischemia and reperfusion injury in mice.Setting:Level I trauma center emergency room and ICU and animal research laboratories.Subjects:Adult human sepsis and trauma patients, wild-caught adult arctic ground squirrels, and sexually mature laboratory mice.Interventions:Ischemia and reperfusion injury was induced in mice by temporary application of tourniquet to one hind-limb. Iodide was administered IV just prior to reperfusion.Measurements and Main Results:Free iodide was measured using ion chromatography. Relative to iodide in plasma from normal donors, iodide was increased 17-fold in plasma from trauma patients and 26-fold in plasma from sepsis patients. In arctic ground squirrels, iodide increases over three-fold during hibernation. And during ischemia/reperfusion injury in mice, iodide accumulates in ischemic tissue and reduces both local and systemic tissue damage.Conclusions:Iodide redistributes during stress and improves outcome after injury. Essential functions of iodide may have contributed to its evolutionary selection and be useful as a therapeutic intervention for human patients.

Facile Synthesis of Antimicrobial Aloe Vera-"Smart" Triiodide-PVP Biomaterials.

Antibiotic resistance is an eminent threat for the survival of mankind. Nosocomial infections caused by multidrug resistant microorganisms are a reason for morbidity and mortality worldwide. Plant-based antimicrobial agents are based on synergistic mechanisms which prevent resistance and have been used for centuries against ailments. We suggest the use of cost-effective, eco-friendly Aloe Vera Barbadensis Miller (AV)-iodine biomaterials as a new generation of antimicrobial agents. In a facile, one-pot synthesis, we encapsulated fresh AV gel with polyvinylpyrrolidone (PVP) as a stabilizing agent and incorporated iodine moieties in the form of iodine (I2) and sodium iodide (NaI) into the polymer matrix. Ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), x-ray diffraction (XRD), microstructural analysis by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) verified the composition of AV-PVP-I2, AV-PVP-I2-NaI. AV, AV-PVP, AV-PVP-I2, AV-PVP-I2-NaI, and AV-PVP-NaI were tested in-vitro by disc diffusion assay and dip-coated on polyglycolic acid (PGA) sutures against ten microbial reference strains. All the tested pathogens were more susceptible towards AV-PVP-I2 due to the inclusion of “smart” triiodides with halogen bonding in vitro and on dip-coated sutures. The biocomplexes AV-PVP-I2, AV-PVP-I2-NaI showed remarkable antimicrobial properties. “Smart” biohybrids with triiodide inclusions have excellent antifungal and promising antimicrobial activities, with potential use against surgical site infections (SSI) and as disinfecting agents.

Silver-iodine association in Hanford nuclear waste

The Hanford Site in the United States has over 200 million liters of alkaline nuclear waste. Radioactive iodine is frequently the limiting radionuclide for disposing of the waste in a repository due to the assumption of high solubility. There has been minimal actual data on the speciation of iodine, however. This study dissolved soluble salts from a Hanford waste sample to concentrated insoluble species and then searched for iodine-species using Scanning Electron Microscopy. Silver-iodine associations were found in the sample using Energy Dispersive Spectroscopy, indicating that this iodine was in the form of silver iodide or iodate. These silver bearing species have relatively low water solubility, which may limit the release of iodine to the environment.

A Bis-organosilyl-Functionalized Wells-Dawson Polyoxometalate as a Platform for Facile Amine Postfunctionalization.

The development of modular platforms that can undergo postfunctionalization reactions permits coupling of inorganic clusters with different organic functionalities, thereby expanding the range of key physicochemical properties that are relevant for applications in different areas of science. In this work, a novel hybrid Wells-Dawson polyoxometalate (POM) platform was developed and successfully used for postfunctionalization via a nucleophilic substitution reaction. Two new halogen-functionalized bis-organosilyl Wells-Dawson POMs TBA6[α2-P2W17O61{O(SiC3H6-X)2}] (X = Cl or I) were synthesized, and their coupling with amine substrates was explored in a one-step postfunctionalization reaction. The iodide form of the POM has proven to be much more reactive, and its reaction with a range of primary and secondary amines resulted in a series of new bis-substituted Wells-Dawson POMs with the general formula TBA6[α2-P2W17O61{O(SiC3H6-NR1R2)2}]. Coupling of 18 amines with R1 and R2 groups, which exhibited a wide variety in terms of both chemical nature and bulkiness, was achieved under mild conditions via a catalyst-free approach. Using Na2CO3 as a base in acetonitrile solutions at 55 °C resulted in hybrid products that were obtained in high purity and good yields, after a simple isolation and purification procedure.

Co-evaporation as an optimal technique towards compact methylammonium bismuth iodide layers

The most studied perovskite-based solar cells reported up to date contain the toxic lead in its composition. Photovoltaic research and development towards non-toxic, lead-free perovskite solar cells are critical to finding alternatives to reduce human health concerns associated with them. Bismuth-based perovskite variants, especially in the form of methylammonium bismuth iodide (MBI), is a good candidate for the non-toxic light absorber. However, the reported perovskite variant MBI thin films prepared by the solution process so far suffers from poor morphology and surface coverage. In this work, we investigate for the first time the optoelectronic, crystallographic and morphological properties of MBI thin films prepared via thermal co-evaporation of MAI and BiI3. We find by modifying the precursor ratio that the layer with pure MBI composition lead to uniform, compact and homogeneous layers, broadening the options of deposition techniques for lead-free based perovskite solar cells.