Ammonium Iodide Research Articles

Synthesis of polysubstituted pyridines from oxime acetates using NH4I as a dual-function promoter.

Pyridine formation with oxime acetates as the building blocks under metal-free conditions is described. Ammonium iodide has proved to be a highly efficient promoter for oxime N-O bond reduction and subsequent condensation reactions, whereby it played a dual-function role in the transformation. While the three-component reaction of oxime acetates, benzaldehydes, and 1,3-dicarbonyls proceeded well with the assistance of a stoichiometric amount of ammonium iodide, the condensation of oximes and acroleins was enabled by using a catalytic initiator to afford substituted pyridines. By this protocol, substituted pyridine products were generated in moderate to excellent yields with tolerance towards a broad range of functional groups.

Superplastic forming of shells from sheet blanks with thermally unstable coatings

The article is devoted to superplastic forming of non-uniformly heated sheet blanks from aluminum alloy AMg6M. To create an uneven temperature field over the surface of the blank, coatings made of sublimated substances were used from at temperatures 50…150°C below the superplastic forming temperature (450°C for AMg6M alloy). An aqueous solute of chloride and ammonium iodide having a sublimation temperature at normal pressure and a latent heat of conversion equal to 338 and 404°C, 330 and 355kJ/kg, respectively, was sprayed onto the central zones of the blanks. Superplastic forming of shells was carried out in two modes: 1) with simultaneous sublimation of the coating; 2) with the beginning of the sublimation of the coating upon reaching the height, which is formed by the workpiece, equal to 20-30% of the final shell height. The experiments showed a decrease in the thickness of the shells to be formed up to 4-10% on the working surface of the shells (without taking into account their flange zones) and the savings of sublimate during superplastic forming in the second mode. The optimal subliming coating for AMg6M alloy was ammonium chloride.

Four-component quinazoline synthesis from simple anilines, aromatic aldehydes and ammonium iodide under metal-free conditions

Substituted quinazoline derivatives were selectively prepared from anilines, aromatic aldehydes and NH4I under metal-free conditions.

Influence of Tetra Alkyl Ammonium Cation on Thermo-Physical Properties of N,N-Dimethyl Formamide with 1,4-Dioxane at Different Temperatures

Ultrasonic technique, transport properties and related acoustical parameters of 1,4-dioxane and N,N-dimethyl formamide were prepared of different % compositions at variable temperatures using tetra alkyl ammonium iodide salts (R4NI) of 0.14 M, to investigate inter-ionic interactions, molecular interactions, molecular rearrangement, molecular association etc. The densities were measured by using magnetic float densitometer. Transport properties provide a deep and meaningful insight of various interactions taking place between the binary liquid mixtures with salts. We have observed the influence of small as well as large alkyl chain length (R4N+), and extract the information with respect to various kinds of intermolecular interactions such as dipole-dipole, dipole-induced dipole, solute-solvent, dispersive type and H-bonding interaction between the components. Such observations in the presence of specific molecular interactions of binary solutions and structural effects were analyzed on the basis of measured and derived thermo-dynamical parameters.

Systematic structure control of ammonium iodide salts as feasible UCST-type forward osmosis draw solutes for the treatment of wastewater

Systematic structure control of ammonium iodide salts is designed using novel UCST-type forward osmosis draw solutes for wastewater treatment.

Development of pma/pvac-tpai-bmii solid polymer electrolytes for application in dye sensitized solar cell

Electrolyte film of poly(methyl acrylate) (PMA) and poly(vinyl acetate) (PVAc) with composition of 90:10 and 20 wt.% of tetrapropyl ammonium iodide (TPAI) at different of 1-butyl-3- methyl imidazoliumiodide (BMII) concentration were prepared by solution casting technique. Highest conductivities achieve at 5wt.% of BMII is 1.2 x 10-11 S cm-1. Effects of temperature of this sample on the dielectric properties was studied by impedance spectroscopy. The dielectric constant, εr and dielectric loss, εi increased with increasing temperature. Charge carrier relaxation time was extracted from the electrical modulus spectra. It was found that the relaxation time decreased with temperature. The ac conductivity was observed to obey the Jonscher’s Universal Power Law. The correlated barrier hopping model (CBH) was used to interpret the conduction mechanism of the present electrolyte system. Electrolyte films were sandwiched between titanium dioxide photoanode and platinum counter electrode for dye-sensitized solar cells (DSSCs) assembly. The solar cell with 5wt.% showed highest efficiency of 4.62% with maximum short circuit current density(Jsc) of 10.04 mAcm-2, open circuit voltage (Voc) 0.70 V and fill factor, ff of 66.04%.

Direct Asymmetric Ruthenium-Catalyzed Reductive Amination of Alkyl–Aryl Ketones with Ammonia and Hydrogen

The asymmetric ruthenium-catalyzed reductive amination employing ammonia and hydrogen to primary amines is described. Here we demonstrate the capability of our catalyst to perform a chemo- and enantioselective process while using simple ammonia gas as a reagent, one of the most attractive and industrially relevant nitrogen sources. The presence of a catalytic amount of ammonium iodide was essential for obtaining good yields and enantioselectivities. The mechanism of this reaction was investigated by DFT and we found a viable pathway that also explains the trend and magnitude of enantioselectivity through the halide series in good agreement with the experimental data. The in-depth investigation of substrate conformers during the reaction turned out to be crucial in obtaining an accurate prediction of the enantioselectivity. Furthermore, we report the crystallographic data of the chiral [Ru(I)H(CO)((S,S)-f-binaphane)(PPh3)] complex, which we identified as the most efficient catalyst in our investigation.

Key parameters of two typical intercalation reactions to prepare hybrid inorganic–organic perovskite films**Project supported by the International Cooperation Project of the Ministry of Science and Technology, China (Grant No. 2014DFE60170), the National Natural Science Foundation of China (Grant Nos. 61474065 and 61674084), Tianjin Research Key Program of Application Foundation and Advanced Technology, China (Grant No. 15JCZDJC31300), Key Project in the

A star hybrid inorganic–organic perovskite material selected as an outstanding absorbing layer in solar cells benefits from multiple preparation techniques and excellent photoelectric characteristics. Among numerous synthetic processes, uniform, compact, and multi-stack perovskite thin films can be manufactured using vacuum deposition. During sequential vacuum deposition, the penetration ability of the organic molecules cannot be effectively controlled. In addition, the relationship between the thickness of the inorganic seeding layer and the organic molecule concentration for optimized devices using an evaporation–solution method is unclear. In this work, we prepared high-quality perovskite films by effectively controlling the penetration ability and chemical quantity of organic methyl ammonium iodide by monitoring the evaporation pressure and time. Thus, a device efficiency of over 15% was achieved with an all-vacuum prepared perovskite film. For the evaporation–solution method, we reacted different thicknesses of inorganic lead iodine with various concentrations of the organic molecule solution. The inorganic layer thickness and organic molecule concentration showed a linear relationship to achieve an optimum perovskite film, and an empirical formula was obtained. This work noted the key parameters of two intercalation reactions to prepare perovskite films, which paves a way to deliver a device that enables multi-layered structures, such as tandem solar cells.

The Influence of CH3NH3I/ Pbi2 Ratio on The Absorption and Electrical Characteristics of Perovskite/Polymer Solar Cell

In this paper, we report a simple solution processed perovskite/polymer solar cell using CH 3 NH 3 PbI 3 as an absorber, PCBM (6,6 phenyl C61-butyric acid methyl ester) as an electron transport layer, and PEDOT:PSS (poly (3,4-ethylene dioxy thiophene):poly(styrene sulfonate)) as a hole transport layer. The absorber solution was prepared by mixing of CH 3 NH 3 I (methyl ammonium iodide) with PbI 2 (lead iodide) in DMF (dimethyl formamide) solvent. The absorber, electron transport, and hole transport layers are deposited by spin coating of the solutions. In order to obtain the optimum optical and electrical characteristics, the mixture of CH 3 NH 3 I and PbI 2 are varied by the molar ratio of 1:1, 1:3, and 3:1, respectively. Because of CH 3 NH 3 PbI 3 layer degrades, the fabricated cells have low performance. However, the cell using a molar ratio of 1:1 CH 3 NH 3 I and PbI 2 gives the best electrical characteristics, results in an open circuit voltage of 0.04 V, a short circuit current density of 0.08 mA/cm 2 , and a power conversion efficiency of 0.002 %.

Transparent and flexible photodetectors based on CH3NH3PbI3 perovskite nanoparticles

Transparent and flexible photodetectors (PDs) based on CH3NH3PbI3 perovskite nanoparticles (NPs) were fabricated by using co-evaporation of methyl ammonium iodide and lead iodide. X-ray diffraction patterns and high-resolution transmission electron microscopy images demonstrated the formation of perovskite NPs. The optical transmittance of the perovskite NPs/glass was above 80% over the entire range of visible wavelengths, indicative of high transparency. The PDs based on CH3NH3PbI3 perovskite NPs were sensitive to a broad range of visible light from 450 to 650nm. The currents in the PDs under exposure to red, green, and blue light-emitting diodes were enhanced to 5, 10, and 20 times that of the PD in the dark, respectively. The rise and the decay times of the PDs were 50 and 120μs. The current in the perovskite NP PD on a polyethylene terephthalate substrate was enhanced by approximately 69% when the NP PD was exposed to a blue LED emitting at a wavelength of 459nm. Despite multiple bending, the transparent and flexible PDs based on methyl ammonium iodide and lead iodide NPs showed reproducibility and high stability in performance.

Importance of PbI2 morphology in two-step deposition of CH3NH3PbI3 for high-performance perovskite solar cells**Project supported by the National Natural Science Foundation of China (Grant No. 61404007) and the Beijing Talents Fund, China (Grant No. 2015000021223ZK38).

Controlling the morphology of the perovskite film is an effective way to improve the photoelectric conversion efficiency of solar cell devices. In this work, we study the influence of the crystallization condition on PbI2 morphology and the performances of resulting perovskite solar cells. The PbI2 morphologies and coverage rates under different formation conditions such as solvent effect, slow crystallization at room temperature and substrate-preheating, are found to be of crucial importance for preparing high-quality perovskite. The generation of loosely packed disk-like PbI2 film with interpenetrating nanopores promotes the penetration of methyl ammonium iodide (MAI), leading to a better crystallinity of the perovskite film, and a best repeatable power conversion efficiency of 11.59% is achieved when methyl ammonium lead triiodide (CH3NH3PbI3, MAPbI3) is employed. In addition, an excellent device is also obtained with an efficiency of more than 93% to remain after working for 43 days.

Ammonium iodide-mediated regioselective chalcogenation of chromones with diaryl disulfides and diselenides

ABSTRACTA metal-free method for the synthesis of 3-chalcogenyl-chromones/quinolones from chromones/quinolones and diorganyl dichalcogenides using ammonium iodide under air was developed. This approach allowed the preparation of a wide range of 3-selenyl- and 3-sulfenyl-chromones/quinolones in good to excellent yields.

A colorimetric and fluorescent chemosensor for detection of Hg2+ using counterion exchange of cationic polydiacetylene

In this study, a colorimetric and fluorescent chemosensor for mercury ions (Hg2+) was developed. Cationic polydiacetylene (PDA) vesicles with a quaternary ammonium cation and iodide as a counterion show a blue-to-red color transition; the color change is accompanied by a fluorescence enhancement in selective response to Hg2+ ions because of a perturbation of the ene–yne conjugated backbone induced by counterion exchange. It allows for selective detection of Hg2+ with the naked eye and the sensor is used to determine Hg2+ concentrations in tap water samples.

Investigation of photovoltaic properties of nanostructure indoline dye-sensitised solar cells using changes in assembling materials

PurposeThe purpose of this paper is to study assembling parameters in dye-sensitised solar cells (DSSCs) performance. For this end, 3a,7a-dihydroxy-5ß-cholanic acid (cheno) are selected as anti-aggregation agent and two solutions, namely, tetrabutyl ammonium iodide and (PMII)IL used as electrolyte.Design/methodology/approachA series of organic dyes were selected using N-substituents carbazole as electron donor group and acrylic acid and cyanoacrylic acid as electron acceptor groups. Absorption properties of purified dyes were studied in solution and on photoelectrode substrate. DSSCs were prepared in the presence of anti-aggregation agent and different electrolyte to determine the photovoltaic performance of each dyes.FindingsThe results showed that all organic dyes form J-aggregation on the photoanode substrate in the absence of anti-aggregation agent and the amounts of aggregation were reduced in the presence of anti-aggregation agent. DSSCs were fabricated in the presence of anti-aggregation agent. The photovoltaic properties were improved using tetrabutyl ammonium iodide as electrolyte. The maximum power conversion efficiency was achieved for D12 in the presence of cheno and tetrabutyl ammonium iodide as anti-aggregation agent and electrolyte, respectively.Social implicationsOrganic dye attracts more and more attention due to low cost, facile route synthesis and less hazardous.Originality/valueThe effect of anti-aggregation agent and electrolyte on DSSCs performance was investigated for the first time.

Fabrication and characterization of mixed lead halide thin films for perovskite solar cells

ABSTRACTRecently, a new class of perovskite was introduced as a light harvesting material that shows strong absorption in a broad region of the visible spectrum, good electron and hole conductivity, and delivers high open circuit voltages in photovoltaic devices. Perovskite solar cells consist of CH3NH3PbX3 loaded on a mesoporous TiO2 layer in conjunction with the hole transporting material between the two electrodes. Optimizing the efficiency of perovskite solar cells is important for light harvesting devices. One approach to improving the efficiency is to increase the charge collection; the electron diffusion length and recombination lifetime influence the performance of perovskite solar cells. In this study, the influence of PbCl2 content in a PbI2 solution of N,N-dimethylformamide (DMF) on the absorption, crystal phase, and morphology of lead halide thin films was systematically investigated and the photovoltaic performance of the corresponding planar perovskite solar cells was evaluated. The planar perovskite solar cell based on the 300-nm-thick methyl ammonium iodide (CH3NH3I):PbI2:PbCl2 (4 M:1.25 M:0.75 M) thin film exhibited the optimum photoelectric conversion efficiency of 6.3% along with an open-circuit voltage of 0.66 V, a short-circuit photocurrent density of 19.60 mA cm−2, and a fill factor of 58.3%.

Polyacrylonitrile gel polymer electrolyte based dye sensitized solar cells for a prototype solar panel

Polyacrylonitrile (PAN) based gel polymer electrolytes (GPE) were prepared using lithium iodide (LiI), 1-butyl-3-methylimidazolium iodide (BMII) and tetrapropyl ammonium iodide (TPAI). The LiI mass fraction in the electrolyte was varied while keeping the masses of other components constant in order to enhance the solar cell performance. The addition of 4.61wt.% LiI in the GPE increased the electrolyte room temperature ionic conductivity from (2.32±0.02) to (3.91±0.04) mScm−1. The increase in conductivity with the addition of LiI salts was attributed to the increase in diffusion coefficient, mobility and number density of charge carriers as determined from Nyquist plot fitting. The incorporation of LiI salts in PAN-based GPE has enhanced the efficiency of the DSSC as expected. The best cell performance was obtained with an electrolyte containing 4.61wt.% LiI sandwiched between a single mesoporous layer of TiO2 soaked in N3 dye sensitizer and a platinum counter electrode, which showed a power conversion efficiency (PCE) of (5.4±0.1) % with a short circuit current density (Jsc) of (21.0±1.1)mAcm−2, an open circuit voltage (Voc) of (0.48±0.02)V and a fill factor (FF) of (53.4±0.9) %. The DSSCs with 4.61wt.% of LiI have been used to fabricate prototype solar panels for operating small devices. The panels were assembled using a number of cells, each having an area of 2cm×2cm, connected in series and parallel. The panel, consisting of a set of eight cells in series which was connected in parallel with another set of eight cells in series, produces an average power conversion efficiency of (3.7±0.2)% with a maximum output power of (17.1±0.9) mW.

A Domino Azidation/C-H Amination Approach toward Trifluoromethyl Substituted Imidazoles.

N-Alkyl enamines can be transformed into 2,4,5-trisubsituted imidazoles by reacting with (diacetoxyiodo)benzene and TMSN3 under the catalysis of a copper salt such as Cu(OAc)2. Tetrabutyl ammonium iodide was also capable of promoting the reaction. The transformation from N-alkyl enamines into 2,4,5-trisubsituted imidazoles took place in a domino azidation/intramolecular C(sp3)-H amination pattern. The present reaction provides a new efficient method for the preparation of 4-(trifluoromethyl) imidazoles.

Investigation of cationized triblock and diblock poly(ε-caprolactone)-co-poly(ethylene glycol) copolymers for oral delivery of enoxaparin: In vitro approach.

The anionic drugs such as proteins, peptides or polysaccharides are generally administered via invasive route causing patient incompliance and high cost of hospitalization. The development of biomaterials for non-invasive delivery of those drugs has gained much attention, especially for oral delivery. However, they have limitation due to non-biocompatibility and poor drug bioavailability. In this study, the novel poly(ε-caprolactone)-co-poly(ethylene glycol) copolymers grafted with propargyltrimethyl ammonium iodide, a small cationic ligand, were introduced to use as a carrier for oral delivery of enoxaparin, a highly negatively charged drug. The study showed that these cationized copolymers could achieve high enoxaparin entrapment efficiency, protect drug release in an acidic environment and enhance enoxaparin permeability across Caco-2 cells, the intestinal cell model. These characteristics of the cationized copolymers make them a potential candidate for oral delivery of anionic drugs for biomaterial applications.

Insights into the phosphatidylcholine and phosphatidylethanolamine biosynthetic pathways in Leishmania parasites and characterization of a choline kinase from Leishmania infantum.

The protozoan parasite Leishmania infantum is a causative agent of the disease visceral leishmaniasis, which can be fatal if not properly treated. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) biosynthesis pathways are attractive targets for new antileishmanial compounds since these Leishmania cell membrane phospholipids are important for parasite morphology and physiology. In this work we observed Leishmania synthesize PC and PE from extracellular choline and ethanolamine, respectively, suggesting the presence of CDP-choline and CDP-ethanolamine pathways. In addition, Leishmania converted PE to PC, indicating the parasite possesses phosphatidylethanolamine N-methyltransferase (PEMT) activity. The first step in the biosynthesis of PC or PE requires the phosphorylation of choline or ethanolamine by a kinase. We cloned the gene encoding a putative choline/ethanolamine kinase from Leishmania infantum and expressed and purified the encoded recombinant protein. The enzyme possesses choline kinase activity with a Vmax of 3.52μmol/min/mg and an apparent Km value of 0.089mM with respect to choline. The enzyme can also phosphorylate ethanolamine in vitro, but the apparent Km for ethanolamine is 850-fold greater than for choline. In an effort to probe requirements for small molecule inhibition of Leishmania choline kinase, the recombinant enzyme was evaluated for the ability to be inhibited by novel quaternary ammonium salts. The most effective inhibitor was N-iodomethyl-N,N,-dimethyl-N-(6,6-diphenyl hex-5-en-1-yle) ammonium iodide, denoted compound C6. In the presence of 4mM compound C6, the Vmax/Km decreased to approximately 1% of the wild-type catalytic efficiency. In addition, in Leishmania cells treated with compound C6 choline transport was inhibited.

Metal‐Free Amine‐Mediated Oxidative Synthesis of Polysubstituted Imidazoles from Aryl Methyl Ketones, Ammonium Iodide or Benzylamine, and Hydrogen Peroxide

AbstractA hydrogen peroxide (H2O2)‐promoted amine‐mediated oxidative coupling reaction between aryl methyl ketones and ammonium iodide leading to (4 or 5)‐aryl‐2‐benzoyl‐imidazole analogs has been developed; these analogs show highly potent antiproliferative activity and can be further developed as promising antitumor agents. This methodology features a one‐step process, metal‐free conditions, high atom economy, good functional group tolerance, and the use of economic and simple starting materials and oxidant. Moreover, the reaction can be scaled up without significant decrease of the yield. Furthermore, 1,2,4‐trisubstituted imidazoles, which are synthetically and pharmaceutically valuable compounds, are produced in the presence of benzylamine. A reasonable mechanism is proposed based on some control experiments.