Search

A crystalline aluminum iodate acid salt has been synthesized from aluminum particles dissolved in iodic acid solution. The precipitate from solution is aluminum iodate hexahydrate [Al(H2O)6](IO3)3(HIO3)2, as confirmed by X-ray diffraction (XRD) analysis. The method of synthesis first dissolves iodine oxide in water, creating an IO3− solution with pH

The reinvestigation of the EDA–HIO3–H2O system using a different stoichiometric ratio gives rise to a new iodate salt C2H10N2(IO3)2.HIO3 denoted as EBIMIA. In this study, we reported the structural properties of ethylenediammonium bis iodate mono iodic acid using X-ray powder and single crystal diffraction at room temperature. The Hirshfeld and the potential energy surface analysis reveal that I⋯O and N–H⋯O are the most noticeable interactions that took place inside the crystal and contribute to the cohesion and stability of the synthesized compound. The DSC measurement shows that this iodate salt undergoes two structural phase transitions, the first occurs at T = 290 K while the second occurs at T = 363 K. However, the dielectric analysis confirms only the second transition because it lies in the studied temperature domain 338–413K. Besides, the impedance data obey a circuit model consisting of a parallel combination of a bulk resistance and CPE. The frequency dispersion of the conductivity follows Jonscher’s law and the charge carrier transport may be interpreted using the correlation barrier hopping mechanism (CBH). Finally, the electronic properties and the vibrational analysis of this novel iodate salt are studied using DFT and compared to the experimental data given by the FT-IR, Raman and UV–visible spectroscopies.

In coastal regions, intense bursts of particles are frequently observed with high concentrations of iodine species, especially iodic acid (IA). However, the nucleation mechanisms of IA, especially in polluted environments with high concentrations of sulfuric acid (SA) and ammonia (A), remain to be fully established. By quantum chemical calculations and atmospheric cluster dynamics code (ACDC) simulations, the self-nucleation of IA in clean coastal regions and that influenced by SA and A in polluted coastal regions are investigated. The results indicate that IA can form stable clusters stabilized by halogen bonds and hydrogen bonds through sequential addition of IA, and the self-nucleation of IA can instantly produce large amounts of stable clusters when the concentration of IA is high during low tide, which is consistent with the observation that intense particle bursts were linked to high concentrations of IA in clean coastal regions. Besides, SA and A can stabilize IA clusters by the formation of more halogen bonds and hydrogen bonds as well as proton transfers, and the binary nucleation of IA-SA/A rather than the self-nucleation of IA appears to be the dominant pathways in polluted coastal regions, especially in winter. These new insights are helpful to understand the mechanisms of new particle formation induced by IA in clean and polluted coastal regions.

The formation of oriented nanostructures of iodic acid (HIO3) on track-etched membranes has been studied. The study has shown that the method of forced filtration of supersaturated crystallization solutions through track membrane pores can be used to grow needlelike faceted microcrystals that have the cross size and preferential growth direction corresponding to those of the pores.

Metal iodates with a lone-pair containing I(V) in an asymmetric coordination geometry can form a diversity of unusual structures, including non-centrosymmetric (NCS) structures with promising second-order nonlinear optical (NLO) properties. They have wide transparent wavelength regions (0.4–12 μm), large second harmonic generation (SHG) coefficients (>10 × KDP for many iodates) and high optical-damage thresholds (4–50 GW cm −2 ) as well as good thermal stability (usually >400 °C). In this review, the structures and second-order NLO properties of metal iodates will be discussed. Under reaction media with a high concentration of iodic acid, the iodate groups can be condensed into binuclear or polynuclear iodate anions, these compounds are able to display large SHG responses. The introduction of other lone pair containing cations into the iodate system is also an effective strategy to design new NCS materials. The combination of d 0 transition-metal cations with iodate groups afforded a large number of NCS metal iodates with anionic structures ranging from 0D clusters, 1D chains, 2D layers to 3D networks. These NCS materials can display excellent second-order NLO properties when the polarizations from both types of the asymmetric units are aligned properly. As for the iodates of d 8 -transition metal ion with a square planar TMO 4 geometry, the cis TM(IO 3 ) 4 unit in which the four iodate groups are located at the same side of the TMO 4 plane favors the formation of NCS structures whereas the trans - one in which the four iodate groups being located at both sides of the TMO 4 square plane prefers to a centrosymmetric structure. NCS structures with good SHG properties can also be found in other mixed metal iodate systems.

Background: Tranexamic acid and etamsylate drugs belong to a group of antifibrinolytics. Tranexamic Acid (TRA) is the most potent antifibrinolytic lysine analogue used in a broad spectrum of peri-and postoperative interventions and bleeding disorders. The administration of TRA is associated with a reduction in bleeding due to its inhibitory effect on clot breakdown (fibrinolysis). Etamsylate (ESL) is a haemostatic agent that appears to maintain the stability of the capillary wall and correct abnormal platelet adhesion. It is given for the prophylaxis and control of haemorrhages from small blood vessels. Objective: Two simple and sensitive spectrophotometric methods are described for the determination of tranexamic acid (TRA) and etamsylate (ESL) drugs in pure form and pharmaceutical preparations. Materials and Methods Method (A) is used for the determination of TRA and based on condensation reaction of the primary amino group of TRA with salicylaldehyde reagent (SA) (Schiff base formation) producing a yellow coloured product which is measured spectrophotometrically at 400 nm. Method (B) is utilized for the determination of ESL and based on the oxidation-reduction reaction of ESL using iodic acid (HIO3). The liberated iodine was extracted in chloroform and the absorbance of the red coloured product is measured spectrophotometrically at 510 nm. For method A and B, different variables affecting the reactions were studied and optimized. Results: Under the optimum conditions, linear relationships with good correlation coefficients 0.9989 and 0.9959 were found between the absorbance and the concentration of the drug in the range from 5 to 500 and 2.5 to 275 μg mLG 1 for ESL and TRA drugs, respectively. The limit of detection (μg mLG 1 ), limit of quantification (μg mLG 1 ) and molar absorptivity (L molG 1 cmG 1 ) values were found to be 1.442, 4.80 and 5.39×10 2 for TRA drug and 2.20, 7.25 and 3.0×10 2 for ESL drug, respectively. Conclusion: The method was applied for determination of the investigated drugs in tablets. The method was validated and can be suggested for routine analysis of both drugs.

Alfred Ditte (1843–1908), a student of Henri Sainte-Claire Deville, carried on a large number of important researches in the areas of mineralogy, chemistry, and thermodynamics, in particular, vanadium and its compounds, properties of aluminum, alumina, and aluminates, the Leclanché cell, dissociation mechanism, and iodic acid and iodates.

International audience; In this paper, the mechanism of the HOIO2 + OH → products reaction is investigated using quantum chemistry tools. Two pathways are considered: HOIO2 + OH → OIO2 + H2O and HOIO2 + OH → OIO + H2O2. The potential energy surfaces are calculated at the CCSD(T)/CBS(D,T)//B3LYP/aug-cc-pVTZ level of theory. The OH radical was found to attack iodic acid from either the frontside (TSHabs) or the topside (TSOHabs), subsequently leading to H- or OH-transfer channels. Reaction enthalpies and standard Gibbs free reaction energies at 298 K are provided. The values indicate that only the HOIO2 + OH → OIO2 + H2O channel is exothermic and exergonic. Theoretical prediction of the kinetic parameters is performed within the framework of the transition state theory (TST) and variational transition state theory (VTST). The rate constants (in cm³ molecule–1 s–1) for temperatures from 250 to 2500 K are kHabs(T) = 1.76 × 10–22T2.39 exp(−3.5 (kJ mol–1)/RT) and kOHabs(T) = 3.16 × 10–21T2.57 exp(−96.2 (kJ mol–1)/RT). The HOIO2 + OH overall reaction is significantly dominated by the HOIO2 + OH → OIO2 + H2O channel for tropospheric temperatures. The main outcomes of this work are as follows: (i) The lifetime of iodic acid toward its removal by OH radicals is extremely long (1336 years), enabling its transportation to different locations around the Earth (marine, polar, and continental), as confirmed by recent field measurements; other possible loss pathways under clear sky (gas phase) and cloudy (aqueous phase) conditions could reduce its atmospheric lifetime. (ii) The thermochemical properties of the OIO2 radical are provided: ΔfH298 K° = 168.3 kJ mol–1, S298 K° = 301.45 J mol–1 K–1, and Cp(300 K) = 65.82 J mol–1 K–1.

A facile and efficient way of generating oxygen vacancies in visible light activated one-dimensional iodine doped TiO2 photocatalysts was first reported in this work. A two-step hydrothermal synthesis was used to synthesize TiO2 nanomaterials modified by iodic acid (HIO3) as a dopant. Detailed analysis was conducted to illustrate the intrinsic doping/reaction mechanisms of iodic acid in the modification of the TiO2 matrix. The phase and structure evolution were deduced from X-ray diffraction (XRD), Raman, and scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) was conducted to analyze the generation of oxygen vacancies and the formation of I–O–Ti bonds in the TiO2 lattice. Multi-valences of iodine, due to the reduction of iodic acid, facilitated the generation of oxygen vacancies and 3d state Ti3+ species in the TiO2 lattice. The visible light absorption and enhanced photocatalytic activity of the TiO2 nanomaterials were attributed to existing oxygen vacancies, iodine multi-valences in I–O–Ti bonds, and 3d state Ti3+ sites in the TiO2 lattice. The photocatalytic degradation efficiency under visible light (λ > 400 nm) followed a pseudo first-order kinetic model. Rutile nanowires using a two-step synthesis method produced the highest methylene blue (10 mg L−1) degradation rate constant, Kap, of 7.92 × 10−3 min−1 compared to other synthesized nanomaterials. The Kap value obtained was an order of magnitude greater than commercial P25 (3.87 × 10−4 min−1) and pristine TiO2 nanowires (4.18 × 10−4 min−1). The iodine doped TiO2 photocatalysts can be used in TiO2/light irradiation advanced oxidation processes (AOPs) in water treatment using sunlight or a visible light source, rather than an ultraviolet irradiation source.

The Ritter-type amination of a tertiary C–H bond using iodic acid (HIO3) as an oxidant, in the presence of N-hydroxyphthalimide (NHPI) is reported. This operationally simple method is conducted under metal-free conditions, is scalable, and efficiently provides valuable α-tertiary amine derivatives.

Catalysis of the oxidative processes by iodoarenes has become a promising direction in synthesis. The mechanism, involving the well-known isolable hypervalent iodine species, is generally limited to aromatic iodides, since the corresponding aliphatic species are normally highly unstable. Nevertheless, in this work catalytic amount of several primary, secondary or tertiary iodoalkanes were found to promotes the α-tosyloxylation of a range of ketones with RSO3H, including aliphatic sulfonates. The process, was found to proceed through the oxidative breakdown of the iodoalkane to an inorganic catalytic species (likely IO− or IO2−), thus falling within the previously described catalysis using molecular iodine or inorganic iodides. The catalyst eventually becomes deactivated through the precipitation of an iodine overoxidation product, the structure of which was solved ab initio from the powder diffraction data as a hitherto unreported phase of the iodic acid (HIO3).

Homogeneous nucleation and subsequent cluster growth leads to the formation of new aerosol particles in the atmosphere(1). The nucleation of sulfuric acid and organic vapours is thought to be responsible for the formation of new particles over continents(1,2), whereas iodine oxide vapours have been implicated in particle formation over coastal regions(3-7). The molecular clustering pathways that are involved in atmospheric particle formation have been elucidated in controlled laboratory studies of chemically simple systems(2,8-10), but direct molecular-level observations of nucleation in atmospheric field conditions that involve sulfuric acid, organic or iodine oxide vapours have yet to be reported(11). Here we present field data from Mace Head, Ireland, and supporting data from northern Greenland and Queen Maud Land, Antarctica, that enable us to identify the molecular steps involved in new particle formation in an iodine-rich, coastal atmospheric environment. We find that the formation and initial growth process is almost exclusively driven by iodine oxoacids and iodine oxide vapours, with average oxygen-to-iodine ratios of 2.4 found in the clusters. On the basis of this high ratio, together with the high concentrations of iodic acid (HIO3) observed, we suggest that cluster formation primarily proceeds by sequential addition of HIO3, followed by intracluster restructuring to I2O5 and recycling of water either in the atmosphere or on dehydration. Our study provides ambient atmospheric molecular-level observations of nucleation, supporting the previously suggested role of iodine-containing species in the formation of new aerosol particles(3-7,12-18), and identifies the key nucleating compound.

The exact mechanisms for new particle formation (NPF) under different boundary layer conditions are not known yet. One important question is if amines and sulfuric acid lead to efficient NPF in the atmosphere. Furthermore, it is not clear to what extent highly oxidized organic molecules (HOM) are involved in NPF. We conducted field measurements at a rural site in central Germany in the proximity of three larger dairy farms to investigate if there is a connection between NPF and the presence of amines and/or ammonia due to the local emissions from the farms. Comprehensive measurements using a nitrate Chemical Ionization-Atmospheric Pressure interface-Time Of Flight (CI-APi-TOF) mass spectrometer, a Proton Transfer Reaction-Mass Spectrometer (PTR-MS), particle counters and Differential Mobility Analyzers (DMAs) as well as measurements of trace gases and meteorological parameters were performed. It is shown that the nitrate CI-APi-TOF is suitable for sensitive measurements of sulfuric acid, amines, a nitrosamine, ammonia, iodic acid and HOM. NPF was found to correlate with sulfuric acid, while an anti-correlation with RH, amines and ammonia is observed. The anti-correlation between NPF and amines could be due to the efficient uptake of these compounds by nucleating clusters and small particles. Much higher HOM dimer (C19/C20 compounds) concentrations during the night than during the day indicate that these HOM do not efficiently self-nucleate as no night-time NPF is observed. Observed iodic acid probably originates from an iodine-containing reservoir substance but the iodine signals are very likely too low to have a significant effect on NPF.

The structures, energetics, and thermodynamic properties of HIO 3 isomers (HOOOI, HOOIO, HOIO 2 , and HIO 3 ) have been computed using CCSD(T)/CBS theoretical method. The spin orbit corrections (SOC) have also been evaluated for the each iodine-containing molecule. The SOC value decreases as the iodine valence increases within the molecule. The results revealed that HOIO 2 was the most stable form and that HOOOI was the next most stable isomer. The standard enthalpies of formation at 298 K have been derived from IO + HO 2 and OH + OIO dissociation pathways. At the CCSD(T)/CBS level on B3LYP geometries, the recommended Δ f H ° 298K is (−95.4 ± 0.3) kJ mol −1 for HOIO 2 , and its computed S ° 298K and C p (300 K) values are respectively 339.12 and 75.28 J mol −1 K −1 . Further, monohydrated and dihydrated complexes of iodic acid have been investigated using DFT and wavefunction methods. Three and six mono- and di-hydrated complexes, respectively, have been identified. The hydrogen bonded complexes (HOIO 2 _1wa and HOIO 2 _2wa) are the lowest lying structures. The thermodynamics of dihydrates have been calculated from the total hydration of iodic acid (HOIO 2 + 2H 2 O). Mono- and di-hydration of iodic acid is a favored process at tropospheric and ambient conditions with the formation of HOIO 2 _1wa and HOIO 2 _2wa at T ⩽ 310 K. The positive Gibbs free energies at high temperatures indicate that gas-phase iodic acid would not be present in a hydrated form inside the nuclear containment building of a pressurized water reactor.

Iodine doped titanium dioxide has been successfully prepared by simple hydrolysis of tetrabutyl titanate in the presence of iodic acid. The adopted method allowed for the production of spherical iodine doped titaniun dioxide nanoparticles with varied amount of iodine content. Analysis by X-ray diffraction, Raman, transmission electron microscopy as well as UV–vis DRS revealed that titanium dioxide nanostructures were doped with iodine which existed in two different valence states I 5+ and I − . The iodine in the form of I 5+ is believed to have doped into the lattice whereas I − was well dispersed on the surface of TiO 2 probably as iodine adducts hence rendering it to be highly absorbing in visible light region. The I-TiO 2 exhibited improved photocatalytic activity toward degradation of acid orange 7 (AO7), methyl orange (MO) and 2,4-dichlorophenol (2,4-DCP) under visible light over the pristine TiO 2 prepared by the same method. High catalytic properties are attributed to iodine doping which led to high specific surface area, absorption in visible region as well as alleviation of charge carrier recombination. The most probable route undertaken in the degradation of AO7 is through indirect oxidation by the hydroxyl radicals.

Effect of iodic acid on the growth and properties of L-arginine phosphate (LAP) single crystals has been studied. The presence of iodic acid in the LAP crystals is confirmed by inductively coupled plasma mass spectrometry (ICP-MS) analysis. The unit cell parameters for pure and iodic acid doped LAP crystals have been estimated using powder X-ray diffraction (XRD) analysis. UV-Visible transmittance spectral studies revealed the transmittance percentage and cut-off wavelengths of pure and doped LAP crystals. Powder second harmonic generation measurement has been carried out for the grown LAP crystals. The dielectric behavior of the grown crystals was analyzed for different frequencies at room temperature.

Zirconium and iodine co-doped titanium dioxide (Zr–I–TiO 2 ) was prepared by the hydrolysis of tetrabutyl titanate, premixed with zirconium nitrate in an iodic acid aqueous solution, followed by calcination in air. The structure and properties of the resultant catalyst powders were characterized by X-ray diffraction, the Brunauer–Emmett–Teller method, X-ray photoelectron spectroscopy, transmission electron microscopy, and UV–vis absorption spectroscopy. The catalytic activity of the catalyst was evaluated by monitoring the photocatalytic decolorization of methyl orange under visible light irradiation. The results showed that the activities of Zr–I–TiO 2 catalysts were higher than that of TiO 2 doped with iodine alone (I–TiO 2 ), and the optimal doping concentration in the Zr–I–TiO 2 calcined at 400 °C was determined to be about 0.05 (molar ratio of Zr:Ti). In addition, the photocatalytic activity of Zr–I–TiO 2 calcined at 400 °C was found to be significantly higher than that calcined at 500 or 600 °C. Based on the physico-chemical characterization, we concluded that the role of zirconium on the I–TiO 2 surface is to increase the number of reactive sites by generating a small crystal size and large surface area. The inhibition of electron–hole pair recombination, by trapping photo-generated electrons with Zr 4+ , did not contribute markedly to the improved photocatalytic activity of Zr–I–TiO 2 .

The synthesis and crystal structure are presented for the ethylenediammonium bis iodate tetra iodic acid. An X-ray investigation has shown that this compound crystallizes in a centrosymmetric monoclinic system, space group P21/c with the lattice parameters: a = 7.2536(2) A, b = 18.5351(5) A, c = 7.5685(2) A, β = 107.937(1)°, V = 968.10(3) A3. The structure was solved from 5281 independent reflections with R 1 = 0.0229 and wR 2 = 0.0428, and refined with 156 parameters. The structure is built up of [(CH2)2(NH3)2]2+ cations connected to the one-dimensional [HIO3]n chains and to the [H2I4O12]2− clusters by a weak N–H···O hydrogen bonds. [100] view of the structure of [C2H10N2] (IO3)2·4HIO3. Hydrogen bonds are represented by broken lines.

This article describes simple and efficient method for the iodination of different aromatic amines, hydroxy aromatic aldehydes, hydroxy acetophenones and phenols using iodine and iodic acid in ethanol as a solvent. Notable advantages include mild reaction condition, no need of catalyst, short reaction time, simple practical procedure, giving excellent yield of the product.

Bromination of alkenes, alkynes, and aromatic amines has efficiently been carried out at room temperature in short reaction times using HIO3/KBr in CH2Cl2/H2O (1:1) to prepare corresponding brominated compounds in excellent yields.

Green, mild and efficient iodination of hydroxylated aromatic aldehydes and ketones using iodine and iodic acid in the solid-state by grinding under solvent-free conditions at room temperature. This method provides several advantages such as environmentally friendly, short reaction times, high yields, non-hazardous and simple work-up procedure.

A combination of iodic acid and potassium iodide has been used for trimethylsilylation of alcohols and phenols in the presence of HMDS and iodination of aromatic amines. The reactions occur very rapidly to provide the products in good to high yields in dichloromethane at room temperature while the use of toxic and corrosive molecular iodine is avoided.

N–I co-doped TiO 2 nanoparticles were prepared by hydrolysis method, using ammonia and iodic acid as the doping sources and Ti(OBu) 4 as the titanium source. The prepared catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and ultraviolet–visible diffuse reflection spectroscopy (UV–vis DRS). XRD spectra show that N–I–TiO 2 samples calcined at 673 K for 3 h are of anatase structure. XPS analysis of N–I–TiO 2 samples indicates that some N atoms replace O atoms in TiO 2 lattice, and I exist in I 7+ , I − and I 5+ chemical states in the samples. UV–vis DRS results reveal that N–I–TiO 2 had significant optical absorption in the region of 400–600 nm. The photocatalytic activity of catalysts was evaluated by monitoring the photocatalytic degradation of methyl orange (MO). Compared with P25 and mono-doped TiO 2 , N–I–TiO 2 powder shows higher photocatalytic activity under both visible-light ( λ > 420 nm) and UV–vis light irradiation. Furthermore, N–I–TiO 2 also displays higher COD removal rate under UV–vis light irradiation.

This work focuses on the structure, morphology and photocatalytic performance of pure TiO2 and IO3--doped TiO2 nanoparticles. The photocatalytic activity IO3--doped TiO2 nanoparticles in the decomposition of monocrotophos (MCP) are illustrated and discussed in comparison with standard Degussa P-25. Furthermore, IO3--doped TiO2 showed high relative photonic efficiency compared with some of the commercial photocatalysts. The obtained results show a significant dependence of the degradation performance on IO3--doped TiO2 nanoparticles’s structural, morphological and composition properties. In particular, smaller particle size, large surface area and the formation of mixed phases of TiO2 by the addition of iodic acid have a beneficial influence to enhance the photocatalytic activity of IO3--doped TiO2 nanoparticles for the degradation as well as mineralization of MCP.

2-Pentafluorophenyl hydrazono alkylphosphonates and phosphine oxides 1 are converted to the corresponding phosphorylated azoalkenes 2 in excellent yields (86–94%) upon treatment with a suspension of iodic acid in dichloromethane at room temperature.

Using high-level ab initio calculations and excited state ab initio molecular dynamics simulations, we show that hydrated iodic acids release hydrogen radicals and/or hydrogen molecules as well as iodine radicals upon excitation. Its photoreaction process involving charge transfer to the solvent takes place in four steps: 1) hydration of the acid, 2) charge transfer to water upon excitation of hydrated acid, 3) detachment of the neutral iodine atom, and 4) detachment of the hydrogen radical. The iodine detachment process from excited hydrated hydro-iodic acids is exothermic and the detachment of hydrogen radicals from hydrated hydronium radicals is spontaneous if the initial kinetic energy of the cluster is high enough to get over the activation barrier of the detachment. The complete release of the radicals can be understood in terms of kinetics. This study shows how the hydrogen and halogen radicals are dissociated and released from their hydrated acids. Simple experiments corroborate our predicted mechanism for the release of hydrogen molecules from iodic acid in water by ultraviolet light.

We determined apparent molar volumes Vϕ at 298.15 ⩽ (T/K) ⩽ 368.15 and apparent molar heat capacities Cp,ϕ at 298.15 ⩽ (T/K) ⩽ 393.15 for aqueous solutions of HIO3 at molalities m from (0.015 to 1.0) mol · kg−1, and of aqueous KIO3 at molalities m from (0.01 to 0.2) mol · kg−1 at p = 0.35 MPa. We also determined Vϕ at the same p and at 298.15 ⩽ (T/K) ⩽ 368.15 for aqueous solutions of KI at m from (0.015 to 7.5) mol · kg−1. We determined Cp,ϕ at the same p and at 298.15 ⩽ (T/K) ⩽ 393.15 for aqueous solutions of KI at m from (0.015 to 5.5) mol · kg−1, and for aqueous solutions of NaIO3 at m from (0.02 to 0.15) mol · kg−1. Values of Vϕ were determined from densities measured with a vibrating-tube densimeter, and values of Cp,ϕ were determined with a twin fixed-cell, differential temperature-scanning calorimeter. Empirical functions of m and T were fitted to our results for each compound. Values of Ka, ΔrHm, and ΔrCp,m for the proton ionization reaction of aqueous HIO3 are calculated and discussed.