Ammonium Iodide Research Articles

Metal‐Free Synthesis of Coumarin‐fused Pyrimidines from 4‐Aminocoumarins via Pseudo Four‐component Reaction

AbstractAn efficient pseudo four‐component procedure for the construction of chromeno[4,3‐d]pyrimidin‐5‐ones, a type of coumarin‐fused pyrimidines, from 4‐aminocoumarins, two molecules of aromatic aldehydes and ammonium iodide under metal‐free conditions is developed. The coumarin‐pyrimidine hybrids readily undergo sequential hydrolysis and alkylation to give all‐carbon substituted pyrimidines in excellent yields. One‐pot synthesis of pyrimidines from readily available 4‐aminocoumarins and other commodity chemicals is exemplified.

Влияние соли бария на кинетику осаждения, морфологию и состав химически осажденных пленок PbS

Thin films of lead sulfide obtained by various physicochemical methods are widely used as IR detectors, ion-selective sensors, sensors of temperature and humidity, in solar radiation converters due to a high absorption coefficient in the infrared spectrum of 1-3 μm. Researchers note technological simplicity, the absence of high temperatures and vacuum, as well as the possibility of light doping of lead sulfide films during their production by chemical bath deposition from aqueous media. In the present work, we studied the kinetics of hydrochemical deposition of the solid PbS phase from the ammonium citrate reaction mixture. The introduction of barium chloride BaCl2 into the reactor in the concentration range from 0.5∙10-5 to 5∙10-3 mol/l has led to an increase in the induction deposition period from 5 to 30 minutes. In this work, polycrystalline films of individual lead sulfide were synthesized, as well as PbS layers doped with iodine and additionally barium with salt content in the last mixtures from 0.5∙10-5 to 5∙10-3 mol/l. The film thickness varied from 350 to 210 nm. An elemental EDX analysis of the obtained PbS films was performed. For the main components contained in the layers (Pb and S), insignificant non-stoichiometry in composition was established. The morphology of films of PbS during their doping with iodine and barium undergoes significant changes. Thus, if an individual PbS is formed from particles whose average size is 250 nm, then introduction of ammonium iodide into the solution leads to the appearance of grains with an average size of 150-200 nm, and adding the barium salt results a slight increase in the grain size up to 150-300 nm. The share of nanoparticles in these layers is 1-4%. The histograms of the distribution of particles in the films, both for individual and doped PbS, are monomodal.

Гидрохимический синтез пленок халькогенидов металлов. Часть 41. Влияние ионов Sr2+ на кинетику осаждения, состав и морфологию тонких пленок PbS

Lead sulphide thin films are one of the most sensitive materials in the visible and near-IR spectral ranges (0.4-3.0 μm) and due to this, they are widely used in optoelectronics. One of the most promising methods for the synthesis of this semiconductor material is chemical bath deposition from aqueous solutions. At the same time, doping additives used to improve the properties of the deposited films. In this paper, we consider the effect of strontium cations Sr2+ on the deposition kinetics of the solid lead sulfide phase, as well as on the thickness, morphology and elemental composition of chemically produced PbS films. According to the results of the study of the precipitation kinetics of PbS(Sr) solid phase, it was found that the introduction of strontium chloride into the reactor inhibits the formation of PbS solid phase during the deposition of PbS films and contributes to a significant increasing of the induction period of its formation. Polycrystalline films of lead sulfide were synthesized by hydrochemical precipitation from the ammonium-citrate reaction mixture with the addition of ammonium iodide and strontium chloride on substrates of glass and glass. The thickness of the films obtained decreased from 400 nm for individual PbS to 350 nm for doped with iodine PbS (I). The thickness reduced from 300 to 150 nm with an increase in the content of strontium chloride in the reaction mixture from 5∙10-5 to 5∙10-3 mol/l. The EDX analysis has observed that PbS, PbS(I) and PbS(I,Sr) films have deficient in sulfur, the iodine content decreases from 1.4 to 1.0 at.% when strontium enters in the semiconductor structure. Electron microscopy has shown that adding ammonium chloride to the reactor leads to crushing of crystallites with a clear edges and an average size of grains for individual PbS film from 300 nm up to ~150 nm. The minimum salt content of strontium (5∙10-5 mol/l) increases by ~2 times the proportion of nanoparticles forming the PbS (I, Sr) film, and at the maximum concentration (5∙10-3 mol/l) their content is slightly reduced from 14 to 11%.

The Optical Band-Gap Evolution in Perovskite-Like Hybrid Iodobismuthates Effected by Nuclearity and Dimension: An Experimental and DFT Calculation Study

Three new perovskite-like hybrid iodobismuthates with two quaternary ammonium cations, namely (BnNEt3)3(Bi2I9) (1) (BnNEt3)4(Bi4I16) (2) and (n-Bu4N)2n(Bi4I14)n (3) (Bn = benzyl, n-Bu = n-butyl), have been synthesized by reacting BiI3 with the quaternary ammonium iodide in molar ratio 2:3 (1), 1:1(2), and 2:1 (3), respectively. All hybrids were characterized by elemental analysis, X-ray diffraction and UV–Vis spectroscopic analysis. Single-crystal X-ray diffraction revealed that hybrids 1 and 2 are di-nuclear and tetra-nuclear cluster structures respectively, while 3 is a polymeric chain structure based on a (Bi4I14) tetra-nuclear cluster unit. Their optical band-gaps have been determined as 2.19 eV(1), 2.16 eV(2), 2.02 eV(3), respectively. The optical band gaps exhibit a structure-related decrease from 1 to 3, in agreement with their color changes and the density functional theory (DFT) calculation results. The DFT calculations also reveal that there is a inversely proportional relationship between the optical Eg and the aggregation degree of the BiI6 octahedra in the hybrid iodobismuthate clusters.

Solvent Engineering of Highly Conductive and Porous Fullerene Ammonium Iodide for Immobilizing Pd Nanoparticles with Enhanced Electrocatalytic Activity Toward Ethanol Oxidation

So far, the application of fullerene derivative support in electrocatalysis has been limited by fullerene’s low electronic conductivity and the difficulty in film morphology control. Although highly conductive (1.5 s m−1) fullerene ammonium iodide (PCBANI) had been demonstrated to be a potential support, the solid self-assembled film is not of benefit for metallic nanoparticle (NP) to exhibit catalytic activity. In this work, we found solvent engineering of pristine PCBANI aggregate could maintain stacked short-range assembly structure and porous morphology. Moreover, PCBANI film fabricated from the optimized DMSO/methanol could immobilize Pd NPs with a uniform size of around 4.8 ± 1.7 nm which was characterized by SEM, TEM, and SAED. The resulting Pd/PCBANI-1-coated electrode exhibits a mass-specific activity for Pd of 3361.0 mA mg−1 at a scan rate of 50 mV s−1 and good stability toward alcohol electrooxidation, which are both significantly higher than that of the Pd/PCBANI-2 fabricated from PCBANI’s acetic acid/methanol dispersion and commercial Pd/C (active carbon). To the best of our knowledge, Pd/PCBANI-1 exhibits almost the highest catalytic activity among the existing fullerene-based Pd nanocatalysts. The high performance of the as-fabricated catalyst is attributed to highly conductive and porous PCBANI support, good dispersibility of Pd NPs on support, and favorable mass transfer.

Surface activities and wetting behavior of fluorocarbon-cationic and hydrocarbon-anionic surfactant mixtures in dilute solutions

The surface activities, adsorption properties, and wettability of perfluoropolyether(3) amide propyl dimethyl ammonium iodide (PFPE-A) and sodium lauryl sulfate (K12) mixtures in dilute solutions were investigated by surface tension, dynamic surface tension, and contact angle measurements. The critical micelle concentration (CMC), surface tension at the CMC (γCMC), maximum surface excess concentration (Γmax), and minimum surface area/molecule (Amin) at the air-water interface were evaluated. The wetting abilities of the binary systems on a low-energy surface were also investigated. The experimental results indicated that the PFPE-A/K12 mixture has a good synergistic effect on the surface tension, and even a small amount of PFPE-A could reduce the surface tension of the latter. The higher the PFPE-A content in the mixture, the greater was the rate of surface tension reduction. The wetting performance of the mixtures was poorer than that of PFPE-A.

Fabrication and Electrocatalytic Performance of Graphene-fullerene Ammonium Iodide Composite Supported Pd Nanocatalyst for Ethanol Oxidation†

Fabrication and Electrocatalytic Performance of Graphene-fullerene Ammonium Iodide Composite Supported Pd Nanocatalyst for Ethanol Oxidation†

Combination of high and low temperature carbon pastes to fabricate counter electrode of perovskite solar cell

The high cost, complicated synthesis and coating process of organic hole-transporting materials such as Spiro-OMeTAD, as well as their negative effect on the stability of the device, are the principal impediments for the commercialization of perovskite solar cells. To overcome these obstacles, the attentions increased toward developing hole-transporting material-free perovskite solar cells. In the present work, perovskite solar cell was fabricated by combining two kinds of carbon counter electrodes, including one layer of mesoscopic carbon paste mixed with terpineol and covered by one layer of carbon paste mixed in ethyl-acetate. The crucial difference between two layers lies in their sintering temperature. Also, different thicknesses for the first carbon layer, as well as the effect of dipping time in methyl ammonium iodide were examined. Following the photovoltaic characterization, the achieved optimized efficiency of the hole-conductor-free perovskite solar cell was 11.82 ± 2.07%. Besides, the thickness of the carbon, layer that affects the conductivity and fill factor, and the appropriate contact between perovskite and carbon counter electrode are considered here as two important parameters in optimizing the efficiency of hole-conductor-free perovskite solar cell.

Self-Catalyzed Living Radical Polymerization Using Quaternary-Ammonium-Iodide-Containing Monomers

Self-catalyzed living radical polymerization using quaternary ammonium iodide (QAI)-containing monomers is reported. The monomer contains a polymerizable methacrylate or acrylate moiety and QAI as a catalytic moiety at the side chain. Several (functional) methacrylates and acrylates were successfully copolymerized with QAI-containing monomers without additional catalysts, generating QAI-containing copolymers. The obtained QAI-containing polymers were further used as catalytic macroinitiators, enabling self-catalyzed block polymerizations of various monomers without additional catalysts. This self-catalyzed living radical polymerization was also used to prepare a QAI-containing polymer brush on a solid surface. This technique is attractive for its wide range of amenable monomers and metal-free nature. The obtained QAI-containing polymers may find biomedical and antibacterial applications.

Synchronization iodine surface modification and lattice doping porous carbon nitride for photocatalytic hydrogen production

Reaction active surface area and energy band structure determine the visible-light photocatalytic property of semiconductor catalyst such as graphitic carbon nitride (CN). Herein, synchronization iodine surface modified and doped porous carbon nitride (CNI) was prepared. The self-assembly precursors from urea and ammonium iodide were firstly obtained by liquid nitrogen-assisted rapid re-crystallization and lyophilization technology. After the heat treatment of above precursors, CNI was easily synthesized. Compared with bulk CN, CNI shows large specific surface area (57.59 m2 g−1), due to freeze-drying treatment and thermal decomposition of ammonium iodide. As electron donors, iodine species can enrich the electron density in the carbon nitride network and tune the electronic band structure. It is important the surface iodine modification can bound the positive charge holes to inhibit the recombination of photogenerated carriers. As a result, CNI exhibits prompted photocatalytic hydrogen evolution rate of 114.0 μmol h−1 under visible-light irradiation (λ > 420 nm), better than that of bulk CN. This work may provide a promising rapid method for designing another porous and effective semiconductor photocatalysts.

Iodine(III)-Mediated, Controlled Di- or Monoiodination of Phenols.

An oxidative procedure for the electrophilic iodination of phenols was developed by using iodosylbenzene as a nontoxic iodine(III)-based oxidant and ammonium iodide as a cheap iodine atom source. A totally controlled monoiodination was achieved by buffering the reaction medium with K3PO4. This protocol proceeds with short reaction times, at mild temperatures, in an open flask, and generally with high yields. Gram-scale reactions, as well as the scope of this protocol, were explored with electron-rich and electron-poor phenols as well as heterocycles. Quantum chemistry calculations revealed PhII(OH)·NH3 to be the most plausible iodinating active species as a reactive "I+" synthon. In light of the relevance of the iodoarene moiety, we present herein a practical, efficient, and simple procedure with a broad functional group scope that allows access to the iodoarene core unit.

BiOCl/AgCl-BiOI/AgI quaternary nanocomposite for the efficient photodegradation of organic wastewaters and pathogenic bacteria under visible light

Sheet-like BiOCl/AgCl-BiOI/AgI quaternary nanocomposites were prepared by a facile single-step co-precipitation method using 1-methyl-3-(oxiran-2ylmethyl)-1H-imidazolium-3-chloride ([MOYI]Cl) ionic liquid (IL) and tetrabuthyl ammonium iodide (TBAI) as Cl and I sources and template agents as well. The products were comprehensively characterized by X-ray diffraction powder (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Diffuse Reflectance Spectroscopy (DRS), nitrogen adsorption-desorption isotherms (BET), and Fourier Transform Infrared spectroscopy (FTIR). The XRD pattern well confirmed the presence of BiOX and AgX (X = Cl and I) crystalline phases in the structure. In addition, the SEM micrographs and TEM image indicated that the sample had sheet-like morphology and the thickness was below 100 nm. Photoactivity of the sample was evaluated by photodegradation of Acid Blue 92 (AB92, an azo dye) and 3-methyl-4-nitrophenol (3M4N, from the semivolatile organic compounds (SVOCs) family) aqueous solutions. According to the results, the product was incredibly efficient for the removal of the contaminants during 120 min of the reaction time. Antibacterial experiments were also conducted and the obtained results showed that the prepared nanostructure had high capacity to decrease the concentration of both gram-negative (E. coli) and gram-positive (S. aureus) pathogenic bacteria after 5 h of the treatment time.

Phase equilibrium measurement and modeling approach to quaternary ammonium salts with and without monoethylene glycol for carbon dioxide hydrates

This experimental work evaluates the thermodynamic hydrate inhibition behavior of three quaternary ammonium salts (QAS) namely tetra ethyl ammonium iodide (TEAI), tetra methyl ammonium bromide (TMAB) and tetraethyl ammonium bromide (TEAB) for carbon dioxide (CO2) hydrates. The Hydrate Liquid Vapor Equilibrium (HLVE) data for CO2 are evaluated through T-cycle method at different temperature (275–283 K) and pressure (2.0–3.50 MPa) conditions in the presence and absence of 5 and 10 wt% aqueous QAS and QAS + MEG solutions. Among all the considered compounds, the inhibition effect of TMAB was found to be the best in pure as well as in mixture with MEG therefore, extended further for 1 wt% also along with 5 and 10 wt%. The inhibition effect including average suppression temperature (ΔŦ) and dissociation enthalpies (ΔHdiss) for hydrate formation are also calculated for the systems taken into consideration. Additionally, a thermodynamic model offered by Dickens and Quinby-Hunt has been used for the prediction of HLVE temperatures of CO2 gas for the considered systems. The results obtained from experimental and modeling data indicate that pure QAS and their mixtures with MEG perform efficiently as thermodynamic hydrate inhibitor for CO2 gas. Therefore, the use of these compounds in thermodynamic inhibition of CO2 hydrates systems can lead towards their application in flow assurance strategies.

High-Detectivity Perovskite Light Detectors Printed in Air from Benign Solvents

Summary Here, we propose a simple and low-temperature approach for the synthesis of methylammonium lead halide perovskite inks based on sub-micrometer-sized particles with tunable band gap. The particles allow the formulation of inks in benign solvents, such as propan-2-ol, and the printing of the photoactive layers of planar photoconductors with scalable, large-area coating techniques under ambient conditions. When surface traps are passivated with [6,6]-phenyl-C61-butyric acid methyl ester fullerene (PCBM), a high photoconductive gain (exceeding 200 in the blue) and reduced noise produce record-high specific detectivities exceeding 7 × 1013 cmHz0.5/W and gain-bandwidth product values of 7.5 × 106 Hz. Given the extreme simplicity of the presented device architecture and the straightforward processing, yielding printable light detectors rivalling established technologies, the present work promises a short-term deployment of printed perovskite detectors in a multitude of opto-electronic applications.

Electrochemical Dehydrogenative Coupling of Alcohols with Hydrogen Phosphoryl Compounds: A Green Protocol for P−O Bond Formation

AbstractThis study reports the environment‐friendly electrochemical transformation of structurally diverse phosphorus compounds and alcohol into phosphonates in the presence of ammonium iodide as electrolyte and redox catalyst in acetonitrile at ambient temperature. This method for P−O bond formation exhibits remarkable features, such as transition metal‐ and oxidant‐free conditions. A reliable mechanism is proposed after control and cyclic voltammetry experiments.magnified image

High‐Performance Perovskite Solar Cells with Enhanced Environmental Stability Based on a (p‐FC6H4C2H4NH3)2[PbI4] Capping Layer

AbstractSupported by the density functional theory (DFT) calculations, for the first time, a fluorinated aromatic cation, 2‐(4‐fluorophenyl)ethyl ammonium iodide (FPEAI), is introduced to grow in situ a low dimensional perovskite layer atop 3D perovskite film with excess PbI2. The resulted (p‐FC6H4C2H4NH3)2[PbI4] perovskite functions as a protective capping layer to protect the 3D perovskite from moisture. In the meantime, the thin layer facilitates charge transfer at the interfaces, thereby reducing the nonradiative recombination pathways. Laser scanning confocal microscopy unveils visually the distribution of the 2D perovskite layer on top of the 3D perovskite. When employing the 3D–2D perovskite as the absorbing layer in the photovoltaic cells, a high power conversion efficiency of 20.54% is realized. Superior device performance and moisture stability are observed with the modified perovskite over the whole stability test period.

Enhanced conductivity of bacterial cellulose films reinforced with NH4I-doped graphene oxide

ABSTRACTBacterial cellulose (BC) films reinforced with reduced graphene oxide (RGO) platelets were investigated to assess their potential application as solid polymeric electrolytes. BC-RGO composites were further doped with NH4I at different concentrations to evaluate the effect of NH4I doping on the conductivity. Scanning electron microscopy images confirmed that GO addition did not alter BC coherent three-dimensional morphology. Electrochemical impedance spectroscopy studies revealed that the ionic conductivity increased with the ammonium iodide salt concentration. The highest conductivity found was 1.32 × 10−4 S/cm for the samples doped with 5% NH4I, suggesting that BC-RGO can be a promising candidate for electrochemical applications.

Photoexcitation of self-n-doped fullerene ammonium halides: The role of halide ion and a possible synergistic dual-redox cycle mechanism within their aggregate

Halide ion’s doping of fullerene core is crucial on the properties of highly conductive self-n-doped fullerene ammonium halides, which are a kind of promising electron transport material for photovoltaics. Herein, to understand their photoexcited electron transfer (ET) property, antimicrobial photodynamic inactivation (aPDI) activities of these materials were tested based on their unique electronic structure and bacterial electrokinesis. We observed that illuminated self-n-doped fullerene ammonium iodides (PCBANI and PCBDANI) could exhibit significant improvement of activity against two important plant pathogenic fungi, Sclerotinia sclerotiorum and Fusarium graminearum as electron donor, compared with that in dark. Through comprehensive studies, such as aPDI activity, hyphal cell morphology, ultrafast transient absorption spectroscopy, solid state nuclear magnetic resonance (ssNMR), level of total cellular reactive oxygen species (ROS), we verified that not ROS but I radical’s oxidative stress is responsible for the improved aPDI activity. Moreover, the photobiological activity of self-n-doped fullerene ammonium halides is dependent on the reducing capacity of halide anions. The ET rate from anion to an excited fullerene core decreased successively from I– to Br– and then Cl–, illustrating that the generation rate of I radical species was the fastest and consistent with the high activity of fullerene ammonium iodides. Remarkably, adding potassium iodide did not enhance PCBANI’s antifungal activity. These results disclose that the unique electronic structure of iodide and fullerene core in self-n-doped PCBANI aggregates are critical for its aPDI activity. Consequently, we propose a possible dual-redox cycles mechanism involving photoexcited fullerene radical anions and I radical species in self-n-doped fullerene ammonium iodide aggregate to exhibit sustainable aPDI activity. This work reveals that halide ions play an equally important role as fullerene core in photoexcited ET property of self-n-doped fullerene ammonium halides.

Organocatalyzed cross-dehydrogenative coupling for C(sp3)–O bonds formation: a rapid access to α-aminoxyl isochromans

Tetrabutyl ammonium iodide catalyzed cross-dehydrogenative coupling reaction between α-C(sp3)–H of isochromans and N-hydroxyphathalimide has been achieved using tert-butylhydroxyperoxide as the terminal oxidant. This method offers rapid access to prevalent α-aminoxyl isochroman architectures. A diverse of synthetic isochromans was tolerated with this protocol, giving the corresponding product in moderate to good yields.

Novel porous organocatalysts for cycloaddition of CO2 and epoxides.

Three classes of organosilicas (DMO, OMOs and PMOs) containing immobilized multi-hydroxyl bis-(quaternary ammonium) iodide salts were prepared and tested in the cycloaddition of CO2 and epoxides. Owing to its higher surface area, pore volume and optimum nucleophilicity of the iodide ion, OMO-2 with two hydroxyl groups was found to be the most active catalyst. For substrates that are easy to activate such as propylene oxide, 1,2-epoxybutane and epichlorohydrin, excellent yields and selectivities were obtained under mild reaction conditions (0.5 MPa CO2, 50 °C and 10–15 h). Moreover, OMO-2 showed very good catalytic properties (yield ≥ 93% and selectivity ≥ 98%), and excellent chemical and textural stability in the synthesis of 1,2-butylene carbonate over 5 cycles.