Metal Iodine Research Articles

Molecular Level Insights into the Chemical Reactivity of Metal Porphyrins and Iodine at the Solution/Solid Interface

Highly oxidized metalloporphyrins (MP) exhibit unusual electronic properties and unique reactivities and are known to serve as intermediates in a number of biological reactions. Of special interest are MP systems that can electronically communicate during the oxidative processes. Model synthetic porphyrins substituted with first row transition metals can react with dihalides and undergo metal oxidation or form MP p-cation radicals. MP dimers that are covalently connected by short alkane or alkene bridges exhibit electronic coupling between the macrocycles which can strongly influence the outcome of the oxidation reaction by dihalides. Metal surfaces also can serve as a conduit for electron transfer and promote cooperative behavior during reactions between adsorbed MP and axial ligands. In this contribution, we present STM experimental results and supporting theoretical calculations of the reactions dynamics of I2 and metal (Co, Zn, and Ni) porphyrins adsorbed on metallic supports. Single molecule level STM imaging was accomplished in-situ under ambient solution conditions. We uncovered unusual surface chemistry and surface modulated cooperativity in the redox reactions. Computations corroborate our experimental findings. The high-resolution images obtained for these reactions at the single molecule level combined with theoretical studies offer insights into surface redox chemistry, surface cooperativity, and surface-driven catalysis.

Activated Opuntia ficus-indica as an efficient adsorbent for iodine and heavy metals Cr(III), Cu(II) and Ni(II) ions uptake for wastewater treatment

Water pollution by heavy metals or iodine is a serious environmental issue that poses a threat to human health and ecosystems. Therefore, there is a need for developing efficient and low-cost methods for removing heavy metals and iodine from water sources. Activated Opuntia ficus-indica (AOFI) has been used for various purposes such as food, medicine, cosmetics, biofuel, and soil stabilization. The aim of this study was to investigate the feasibility of using AOFI as an adsorbent for removing heavy metals; e.g. Cr(III), Pb(II), and Cu(II) and iodine from water. The leaves of AOFI that were collected from Al-Baha city, KSA, were carbonized and characterized using FTIR spectroscopy and TGA analysis. Then uptake experiments were performed to evaluate the effects of various parameters such as pH, contact time, initial concentration, and temperature on the removal uptake by AOFI. Also the thermodynamic and kinetic parameters of the adsorption process had been calculated. The adsorption capacity of AOFI and OFI against iodine, Cr(III), Pb(II), and Cu(II) had been calculated. The results showed that; AOFI has adsorption capacity 1.14, 1.14, and 1.16 times higher than OFI, for Cr(III), Pb(II), and Cu(II), respectively, and 1.05 times higher than OFI, for iodine uptake. The findings indicated that AOFI exhibited remarkable efficacy in the metal ions uptake, achieving uptake efficiency up to 70%. Additionally, AOFI demonstrated notable efficiency in iodine uptake, reaching up to 60%. These results underscore the high uptake efficiency of AOFI for both metal ions and iodine, emphasizing its potential as an effective adsorbent for water treatment applications. This study is novel because it is the first to report the adsorption of heavy metals; such as Cr(III), Pb(II), and Cu(II) and iodine by AOFI.

Fabrication of high-efficiency perovskite solar cells and mini-modules by expanding the processing window with KSCN additive

Perovskite solar cells (PSCs) have garnered significant attention due to their high efficiency and low cost, making them a promising contender for the future of photovoltaic (PV) technology. Stable and controllable preparation of high-efficiency PSCs is crucial for the advancement of perovskite PV technology's industrialization. Herein, we demonstrate an additive-assisted blade-coating technique that boasts a wide air knife pressure window processing, making it ideal for the scalable deposition of perovskite films. KSCN was added to the perovskite precursor to induce an extra endothermic reaction, which effectively reduced the solvent evaporation rate, broadened the processing window, and slowed down the nucleation and crystallization process of the perovskite film. Moreover, the introduction of K+ led to the suppression of the formation of metal Pb0 and iodine vacancies in the film. Therefore, the high-quality perovskite films with full coverage, larger grains, higher crystallinity, fewer defects, as well as large-scale uniformity can be obtained under variable air knife pressure. As a result, power conversion efficiencies of 20.40% for small-area (0.07 cm2) blade-coated PSCs and 17.62% for perovskite solar modules with an active area of 10.00 cm2 were achieved. The proposed blade-coating technique with a wide processing window holds great potential for the commercialization of perovskite PV technology.

Mixed Organic Halide Perovskite Energy Harvester for Solar Cells

Organic- inorganic hybrid perovskite shows promising properties such as optical, electrical, and magnetic. To address issues in the standard methylammonium lead iodide perovskite such as toxicity and stability, lead was replaced with Cu in metal ion part and iodine replaced by chlorine in the anionic position. In this work, methyl ammonium copper chloride (MA2CuCl4) and phenyl ethyl ammonium copper chloride (PEA2CuCl4) were synthesised. Optical and structural property variations of solution obtained by mixing MA2CuCl4 and PEA2CuCl4 in 1:1 ratio was studied. Methylammonium lead iodide has a wide range of applications, particularly in solar cells and photovoltaic systems. Phenylethyl ammonium copper chloride material exhibits both ferroelectric and ferromagnetic properties. Methylammonium copper chloride is hygroscopic and unstable. To increase the stability of the material the organic part can be replaced with higher-order functional groups. Phenylethyl ammonium copper chloride is found to be thermally stable and has more moisture resistance ability compared to methyl ammonium copper chloride. From angle of efficiency, methyl ammonium copper chloride possessed higher performance than phenylethyl ammonium copper chloride, particularly in the field of solar cell perovskites. Uv-vis spectroscopy, FE-SEM, XRD, FTIR characterizations were done.

Metal–iodine batteries: achievements, challenges, and future

This review details past attempts, breakthroughs, and computational/characterization methods in developing metal–iodine batteries along with their key innovations, deficiencies, and possible solutions.

Determination of the microbial and physiochemical composition of branded and unbranded Shea butter

Shea butter samples were randomly obtained from different local markets and supermarkets from two states in Nigeria for the unbranded and branded samples respectively. Isolation and identification of microbial contaminants as well as determination of some physiochemical parameters such as heavy metal levels, saponification and iodine composition for branded and unbranded samples. The Total heterotrophic Fungi count of unbranded samples ranged from 8.50×104 cfu/g to 3.20×107cfu/g while the branded samples showed no significant count, the total heterotrophic bacteria count of unbranded and branded samples ranged from 1.25×106cfu/g to 3.35×108cfu/g, total coliform counts ranged from 1.2×102cfu/g to 2.15×103cfu/g, total Staphylococcus counts of the unbranded and branded samples ranged from 2.71×105 to 3.55×105, The isolated microorganism include: Aspergillus niger (40%), Candida species (30%), Aspergillus fumigatus (10%), Penicillium species (10%) and Blastomyces species (10%). Escherichia coli (26.67%) Pseudomonas species (13.33%), Klebsiella specie (13.33%), Staphylococcus species (26.67%) and Bacillus species (20%). Significant difference was observed in saponification (183.73mgKOH/g and 174.46mgKOH/g) and iodine (40.6I2/100g and 37.94I2/100g) values respectively. Heavy metals present in the branded sample were manganese (Mn), iron (Fe) and zinc (Zn) while iron (Fe) and zinc (Zn) only were present in the unbranded sample. It can also be deduced that shea butter exposed and sold in the local markets and the branded samples which are not properly packaged harbor microbes and this may be harmful to the health of the users mostly newborn and those with injury on their skin. it is recommended that the Shea butter should be properly packaged or covered at sales point in order to reduce microbial re-contamination.

Redox catalysis-promoted fast iodine kinetics for polyiodide-free Na–I2 electrochemistry

Electrochemically reversible I2/I− two-electron conversion and eliminating I3− formation are the ultimate targets for high-performance metal–iodine batteries.

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.

Halogen Bonding Involving I2 and d8 Transition-Metal Pincer Complexes

We systematically investigated iodine–metal and iodine–iodine bonding in van Koten’s pincer complex and 19 modifications changing substituents and/or the transition metal with a PBE0–D3(BJ)/aug–cc–pVTZ/PP(M,I) model chemistry. As a novel tool for the quantitative assessment of the iodine–metal and iodine–iodine bond strength in these complexes we used the local mode analysis, originally introduced by Konkoli and Cremer, complemented with NBO and Bader’s QTAIM analyses. Our study reveals the major electronic effects in the catalytic activity of the M–I–I non-classical three-center bond of the pincer complex, which is involved in the oxidative addition of molecular iodine I2 to the metal center. According to our investigations the charge transfer from the metal to the σ* antibonding orbital of the I–I bond changes the 3c–4e character of the M–I–I three-center bond, which leads to weakening of the iodine I–I bond and strengthening of the metal–iodine M–I bond, facilitating in this way the oxidative addition of I2 to the metal. The charge transfer can be systematically modified by substitution at different places of the pincer complex and by different transition metals, changing the strength of both the M–I and the I2 bonds. We also modeled for the original pincer complex how solvents with different polarity influence the 3c–4e character of the M–I–I bond. Our results provide new guidelines for the design of pincer complexes with specific iodine–metal bond strengths and introduce the local vibrational mode analysis as an efficient tool to assess the bond strength in complexes.

Boosting Energy Storage via Confining Soluble Redox Species onto Solid–Liquid Interface

AbstractAn upswell in the demand for both high energy density and large power density has triggered extensive research in developing next‐generation energy storage systems (ESSs), including redox‐enhanced electrochemical capacitors, metal–sulfur (LiS and NaS) batteries, and metal–iodine (LiI2, NaI2, etc.) batteries, which involve a liquid reaction pathway that decouples the reaction kinetics from the sluggish ion diffusion in the solid phase. Development is plagued at present by the shuttle effects of soluble redox species (SRSs) resulting in poor cycling stability and rapid self‐discharge. Based on the shuttle mechanisms of SRSs, it is crucial to build an atomic or molecular relationship between the electrode surface and SRSs, that is, solid–liquid interface. Here, a timely review of current advances towards the confinement of SRSs in ESSs through solid–liquid interfacial manipulation at the atomic/molecular level is presented. Particularly, the immobilization mechanisms of SRSs around electrode materials within a series of successful examples are highlighted. The corresponding promising research avenues and challenges via interfacial manipulations are also outlined. With this work as a background, new insights into promising strategies that effectively confine the SRSs around electrodes are discussed, with the aim to facilitate vertical leaps in the performance of next‐generation ESSs.

Mild, Efficient, and Highly Regioselective Synthesis of 2,6-Diiodobenzaldehyde Derivatives

An efficient and versatile synthesis of 2,6-diiodobenzaldehydes via highly regioselective metal–iodine exchange (MIE) of 5-substituted 1,2,3-triiodobenzenes is reported. The nature of substituents (R) on the phenyl has a large influence on the reactivity of reaction but not on the regioselectivity. The regioselectivity of the MIE can be controlled by the use of ethyl formate as a formylating agent providing only the internal benzaldehyde derivatives in excellent site-selectivity. The best reactivity and the highest isolated yields were furnished with products bearing electron-rich substituents. Several chemical transformations of the target compound as a valuable precursor in synthesis were also demonstrated providing the desired derivatives in good isolated yields. This report discloses a protocol for the synthesis of 2,6-diiodobenzaldehyde derivatives that is scalable, general in scope, and indeed difficult to be made by other means.

Chemoselective Oxidative Spiroetherification and Spiroamination of Arenols Using I+/Oxone Catalysis.

We developed a chemoselective oxidative dearomative spiroetherification and spiroamination of arenols using I+/oxone catalysis. The intramolecular dearomative C-O and C-N couplings proceeded much more efficiently under slightly acidic conditions to give the corresponding spiro adducts in higher yields compared with previous methods using transition metal or hypervalent iodine catalysts. Control experiments suggested that both hypoiodous acid and iodine might be active species for these reactions.

Easy Access to Crystalline Indolines via Hydrogen Bond Transfer

Several indoline derivatives with specific geometries are biologically active and have inhibitor properties. Many indolines are a key part of natural products. Much attention has been focused on the development of synthetic routes for their easy access. Current synthesis depends largely on metal catalysis, iodine reagents, and Oxone. To date, no synthetic route has been established that is metal‐free, reagent‐free, and environmentally friendly and provides a base for green chemistry. Here, we report the first facile metal‐free and reagent‐free synthesis of indoline derivatives, which could potentially be influential in the design of new biologically active compounds. The synthesis proceeds through intramolecular amination between a urea nucleophile and unactivated alkene. The ring closure occurs in a few hours in the presence of pre‐dried silica gel and gives good yields of indolines products, but in the absence of silica gel, the ring closure occurred overnight with stirring in dry solvent. An electron withdrawing group at the substituted aryl moiety of ureas increases the hydrogen bond donor ability of substrates that mediate the internal proton transfer at the terminal alkene and results in facile amination to give the indoline product with an “in plane” orientation of the carbonyl group and aromatic part of indoline framework. Such orientation in indolines is important for potent biological activities.

Janus triple tripods build up a microporous manifold for HgCl2 and I2 uptake.

To boost the design of microporous solids, we integrated a two-faced shape (as in cucurbiturils and cyclodextrins) into the building blocks of framework materials. Reported herein is a planar tritopic carboxyl linker with secondary tripod donors sprouting off both sides at the core region. The two-faced, barrel-like core region imparts a rugged 3D character to the linker architecture, obviating close packing and creating complex-shaped cavities in an Eu(iii)-carboxylate network. The merits extend beyond the interesting shape of the multiple tripod: e.g., the two sets of sulfur tripods at the barrel region, together with the triazine center, offer a rich array of donors for adsorbing Hg(ii) ions. The microporous solid also removes iodine from vapor and water, and can be easily cycled in column chromatography.

Chemical Synthesis of Niobium Diboride Nanosheets by a Solid-State Reaction Route

A new process was developed to synthesize niobium diboride (NbB2) nanosheets with the dimension of about 500 nm and thickness of about 10 nm by using metal niobium, iodine and sodium borohydride as starting materials in an stainless steel autoclave at 700°C. Iodine was used to facilitate the exothermic reaction between metal niobium and sodium borohydride and the formation of NbB2. X-ray powder diffraction pattern indicated that the obtained product is hexagonal phase NbB2 with the calculated lattice constants a = 110 A and c = 3.2929 A. The obtained product was also studied by thermogravimetric analysis. It had good oxidation resistance below 400°C in air.

Combustion of energetic iodine-rich coordination polymer – Engineering of new biocidal materials

Development and molecular engineering of new highly-efficient energetic biocidal materials is a significant challenge and of a great importance. Until now this type of materials included mostly halogen-rich nano-thermites and iodine-rich organic materials. So far, no energetic coordination polymers were reported as precursors for combustion-generated biocidal agents. Here, we demonstrate for the first time the synthesis of uniquely-structured three-dimensional energetic coordination polymer (ECP3) containing Zn metal centers and iodine- and nitrogen-rich bridging ligand (2). Upon its combustion, ECP3 is capable of generating gaseous reactive iodine species and elemental iodine-coated ZnO particles. ECP3 presents a novel approach for the design of efficient biocidal agents.

Naturally abundant high-performance rechargeable aluminum/iodine batteries based on conversion reaction chemistry

Optimized structure of discharging products in different metal–iodine batteries and electrochemical performance of aluminum/iodine batteries.

In situ chemical vapor deposition of metals on vapor-grown carbon fibers and fabrication of aluminum-matrix composites reinforced by coated fibers

Aluminum, nickel, silicon, and titanium were deposited onto the surfaces of vapor-grown carbon fibers (VGCFs) using a simple and cost-effective in situ chemical vapor deposition method. This process began with the in situ reaction of metal powders and iodine in heated quartz tubes, leading to the formation of metallic iodide vapors. Aluminum was deposited by annealing at 500 °C, forming almost homogeneous metallic aluminum layers on VGCFs. Aluminum-matrix composites reinforced by aluminum-coated VGCFs were fabricated by powder metallurgy. The tensile strength of these composites was improved by the aluminum-coating treatment. Nickel was deposited by annealing at 600 °C. The coating layer consisted of grains smaller than 5 nm. Molten aluminum was dropped on sheets comprising nickel-coated VGCFs, and the contact angle was measured; the wettability was found to be clearly improved. Composites containing nickel-coated VGCFs were fabricated via hot extrusion of a mixture of Al–7Si alloy and VGCFs at semisolid temperature. Vickers microhardness values of the composites were improved by nickel-coating treatment because of improved interaction of the aluminum matrix and VGCFs at the interface. A metallic silicon-coating layer was formed by annealing at 1100 °C. For titanium coating, the reaction of VGCFs with titanium and conversion of the VGCF surface into titanium carbide was confirmed. In the case of titanium, metallic titanium could be deposited without the use of iodine.

First-Principles Screening of Lead-Free Methylammonium Metal Iodine Perovskites for Photovoltaic Application

Although organo-halide lead perovskite solar cells have achieved outstanding photovoltaic performance in recent years, environmental concern about lead pollutant limits its large-scale commercialization. To address lead-free organo-halide perovskite materials, here we report first-principles screening of different perovskite materials MAXI3 with consideration of all possible (27 in total) divalent metal ions. Ten kinds of perovskite structures are obtained with a nonzero bandgap, and the others are metallic. Among them, five kinds of perovskite materials (MAXI3: X = Pb, Sn, Ge, Cd, Be) have appropriate bandgaps as the light-absorbing material in solar cells, in which MACdI3 and MABeI3 are reported for the first time. Various corresponding experiments have been carried out to confirm our theoretical predictions.

Reduced Graphene Oxide/LiI Composite Lithium Ion Battery Cathodes.

Li-iodine chemistry is of interest for electrochemical energy storage because it has been shown to provide both high power and high energy density. However, Li-iodine batteries are typically formed using Li metal and elemental iodine, which presents safety and fabrication challenges (e.g., the high vapor pressure of iodine). These disadvantages could be circumvented by using LiI as a starting cathode. Here, we present fabrication of a reduced graphene oxide (rGO)/LiI composite cathode, enabling for the first time the use of LiI as the Li-ion battery cathode. LiI was coated on rGO by infiltration of an ethanolic solution of LiI into a compressed rGO aerogel followed by drying. The free-standing rGO/LiI electrodes show stable long-term cycling and good rate performance with high specific capacity (200 mAh g-1 at 0.5 C after 100 cycles) and small hysteresis (0.056 V at 1 C). Shuttling was suppressed significantly. We speculate the improved electrochemical performance is due to strong interactions between the active materials and rGO, and the reduced ion and electron transport distances provided by the three-dimensional structured cathode.