Formation Of Molecular Iodine Research Articles

Preparation of Ag/C Nanocomposites Based on Silver Maleate and Their Use for the Analysis of Iodine Ions

In recent decades, metal-containing nanocomposites have attracted considerable attention from researchers. In the present study, a detailed analysis of the preparation of Ag/C nanocomposites through the thermolysis of silver maleate was carried out. Thermolysis products are nanocomposites containing silver nanoparticles (NPs) uniformly distributed in a stabilizing carbon matrix. The composition, structure, and properties of the obtained nanocomposites were studied using IR-spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). This article reports on the possibility of using Ag/C nanocomposites to create new indicator papers that are sensitive to iodide ions in the concentration range of 0.03–1.6 mg/L (0.24–12.6 μM). The developed papers are used in a technique based on the oxidation of iodides with the formation of molecular iodine, which is extracted in an air stream and transferred to a sensitive paper layer containing silver NPs. The interaction of silver NPs with iodine leads to optical changes that can be tracked using a conventional scanner.

Study of the distribution of the coordinating compound C11H12N2O2•(C11H13N2O2)+•NA+•2Н2О•(I4)2- in mice organism by radioisotope method

The paper presents the results of studies on the effect of a new synthesized coordination compound based on an amino acid-tryptophan and iodine compounds on bacterial DNA and the kinetics of its distribution in mice tissues after a single intravenous or oral administration. A radiochemical study of the quantitative content of the coordination compound labeled with iodine-131 in the system of laboratory mice after intravenous and oral administration showed the presence of an isotopic label in the tissues and organs under study. The coordination compound has the ability to accumulate in internal organs and tissues in various concentrations with a further decrease by 24 hours (study period) and clearance of the drug from the body. The effect of a solution of a coordination compound labeled with the 131I isotope on the E. coli culture ATCC 25922 showed that DNA halogenation occurs due to the breakdown of the tryptophan-tetraiodide iodine complex in the cell with the formation of molecular iodine.

Control of optical transparency and infrared laser heating of costal cartilage via injection of iohexol.

Infrared (IR) laser impact has no analogues for rapid and safe cartilage reshaping. For better penetration of radiation optical clearing agents (OCAs) can be applied. In present work, the effect of low-osmolality agent iohexol on costal cartilage is studied. Specifically, it is shown that ½ of total increase of optical transparency occurs in 20 minutes of immersion. Maximally, cartilage transparency on 1560 nm can be increased in 1.5 times. Injection of iohexol results in increased tissue hygroscopicity, lower drying rate and higher percentage of bound water. Effective diffusion coefficients of water liberation at 21°C are (5.3 ± 0.4) × 10-7 and (3.3 ± 0.1) × 10-7 cm2 /s for untreated and iohexol-modified tissue, respectively. Raman spectroscopy of irradiated iohexol solution reveals its photo and thermo-stability under clinically used IR laser energies up to 350 W/cm2 for exposure times of several seconds. At energies higher than 500 W/cm2 [Correction added on 5 September 2018, after first online publication: This unit has been changed] decomposition of iohexol occurs rapidly through formation of molecular iodine and fluorescent residue.

ChemInform Abstract: Electrochemically Promoted Synthesis of Polysubstituted Oxazoles from β‐Diketone Derivatives and Benzylamines under Mild Conditions.

AbstractThe key‐step for the reaction is the formation of molecular iodine in situ.

Towards Controlling Photochemical Reactivity in Small Polyatomic Molecules in Solution: Difluorodiiodomethane

Ultrafast transient absorption and tools of computational photochemistry monitor the efficient formation of molecular iodine from difluorodiiodomethane promoted to the lowest excited state in inert solvents: this requires significantly larger photon energies in the gas-phase.

Electronic structures and reactivities of iodinating agents in the gas phase and in solutions: A density functional study

The electronic and spatial structures of a broad spectrum of neutral compounds with X-Hal (X = N, O, Cl; Hal = Cl, Br, I) bonds and their protonated forms and of different electronic states of triiodide cation, I3 +, were determined from density functional B3LYP/6 311G* quantum chemical calculations. The effects of the structure of these compounds on the parameters of electrophilic reactivity were revealed and the thermochemical characteristics of homolytic and heterolytic X-Hal bond dissociation and of iodine transfer in hydroxyl-containing solvents were calculated. Due to low homolytic bond dissociation energies of X-I, the formation of molecular iodine and triiodide cation I3 + becomes thermodynamically favorable and the cation should act as iodinating agent alternative to acylhypoiodites and N-iodoimides. The solvation effects of MeOH and CH2Cl2 on the X-Hal bond homolysis and heterolysis were determined using the PCM model.

Formation of molecular iodine by photodissociation of CF 2I 2 at 193 nm

Difluorodiiodomethane CF 2I 2 has been studied by photofragment translational energy spectroscopy at 193 nm. The analysis of the TOF spectra revealed three decay pathways: a three-body decay CF 2I 2+ hν → CF 2+I+I (75%) and two distinctly different molecular decays CF 2I 2+ hν → CF 2+I 2 (21%) followed by a complete secondary decay of I 2 to I+I, and CF 2I 2+ hν → CF 2+I 2 (4%) producing stable iodine molecules. The latter involves electronic product excitation consistent with CF 2 in its first excited singlet state. The measured anisotropic recoil distributions are in agreement with these processes and indicate absorption at 193 nm to prepare mainly an electronic state of A 1 symmetry.

KINETICS OF NUCLEOPHILIC ATTACK ON COORDINATED ORGANIC MOIETIES. PART 32.* SYNTHETIC AND MECHANISTIC STUDIES OF THE REACTION OF IODINE ION WITH [(η5-DIENYL)Fe(CO)3]+CATIONS (DIENYL = C6H7, 2-MeOC6H6, C7H9)

The reactions between I− and the cations [(η5-dienyl)Fe(CO)3)]+ (dienyl = C6H7, 2-MeOC6H6, or C7H9) provide a rare example in which attack occurs at each of the hydrocarbon, carbonyl and metal centres. In the case of the C6H7 and 2-MeOC6H6 complexes ring adduct formation predominates, whereas with the more sterically crowded C7H9 substrate the dominant pathway is CO ligand substitution. A minor organometallic product formed in CH3NO2 and acetone solvents is believed to be the novel acyl iodide adduct [(η5-dienyl)Fe(CO)2(COI)]. However, in CH3CN this latter species is not observed. Concomitant formation of molecular iodine occurs, which is converted to I3 − in the presence of the large excess of I− employed. This suggests that a single electron transfer (SET) mechanism is operating, involving initial transfer of one electron from the I− to the dienyl cations and the formation of iodine radicals. Kinetic studies in various solvents, showing the general rate law Rate = k[Fe][I−], are consistent with rate-determining initial electron transfer followed by rapid reaction between the radicals formed to give the observed products.

Formation of molecular iodine during oxidation of iodide by the peroxidase/H 2O 2 system : Implications for antithyroid therapy

The first step in the biogenesis of thyroid hormones is the oxidation of iodides taken up by the thyroid gland. Oxidation of I − by the H 2O 2/peroxidase system leads to the formation of iodinium ions I + which bond to thyroglobulin by electrophilic substitution. However, it is not clear whether I − is transformed directly to I + or whether it passes through a molecular iodine intermediate. This latter possibility is indicated by the oxidation potentials of the reactions. I 2 can be detected in vitro from the formation of I 3 − ions, although this has yet to be confirmed in vivo. The present study was designed to determine, albeit indirectly, whether this reaction occurs in vivo. If I 2 is produced, it may form charge transfer complexes with numerous drugs. We also investigated the action of various drugs on lactoperoxidase and assessed their antithyroid activity in the rat by assay of plasma levels of T 3, T 4, and TSH. We found a good correlation between the value of K c , the formation constant of the complex of the drug with molecular iodine, and the antithyroid activity in vivo. This correlation was observed in four different classes of compound. The possibility that molecular iodine is produced in the thyroid gland has implications for antithyroid therapy.

Characteristics of the electron beam pumped iodine monofluoride laser

Electron beam pumping of Ar/CF 3 I/NF 3 mixtures yields optical pulse lengths \sim0.5 \mu s from iodine monofluoride. Laser efficiency in this system is ∼0.04 percent. Laser performance is limited by the formation of molecular iodine. The formation of molecular iodine in the excited state (I* 2 ) reduces the number of iodine atoms available to form IF*. In the ground state, molecular iodine (I 2 ) absorbs the IF* laser emission at 485 and 491 nm.