Comparison of the electrophilic and free-radical addition of halogens with hexafluoro-1,3-butadiene and 1,3-butadiene

Ionic and photochemical reaction of chlorine (Cl₂), bromine (Br₂) and iodine monochloride (ICl) to hexafluoro-1,3-butadiene (1) and 1,3-butadiene (2) were carried out under conditions that would provide product distributions under controlled ionic or free-radical conditions. Product distributions for ionic reaction of Cl₂ and Br₂ with 1 are similar and suggest a weakly-bridged halonium ion species. Theoretical calculations support weakly-bridged chloronium and bromonium ions for both dienes 1 and 2. There are more of the 1,4-dihalo-2-butene products from ionic halogenation of 1 than 2 which correlates with the greater charge density on carbon-4 of halonium ions from 1. Ionic and free-radical reactions of ICl with 1 give 8 and 2% of 3-chloro-4-iodohexafluoro-1-butene and 4-chloro-3-iodohexafluoro-1-butene, respectively. The minor cis-1,4-dihalo-2-butene products from 1 and 2 are reported when formed.     

A density functional study on the formation of charge transfer complexes between alkaloids and iodine monochloride

The formation of charge-transfer (CT) complexes between N-methyl-6,7-methylenedioxy-tetrahydro-4-isoquinolone (MMDTIQ, the model molecule of alkaloids) and iodine monochloride has been studied with the density functional B3LYP method. The competition for ICl between n-donor(s) and π-donor in the same molecule has been compared for the first time. The results indicate that the electron-donating ability of various donor sites decreases in the following order: amino nitrogen>carbonyl oxygen>etheric oxygen≈aromatic ring. Complexes with a stoichiometry of 1:1 to 1:5 (MMDTIQ–ICl) might form. Among complexes with a given stoichiometry, the one in which the phenyl ring is involved in the binding is always the least stable. According to these results, in order to ensure an alkaloid iodinated, the amount of ICl should be far beyond that of alkaloids and a low polar solvent should be used, which is quite in agreement with our recent experimental results.     

Natural zeolitic material of the clinoptilolite type doped with iodine and its ions

The aim of this study was the preparation of natural zeolitic materials doped with iodine and its ions. Natural zeolite from an East Slovakian deposit was used. The content of iodine in the zeolitic products depended on the experimental conditions used for the preparation. The products and their intermediates obtained at 100, 200, 400 and 900°C were identified.     

Molecular and crystal structure of nido-9-C5H5N-11-I-7, 8-C2B9H10: Supramolecular architecture based on hydrogen bonds X-H⋯I (X = B, C)

A single crystal X-ray diffraction study of a new iodine-containing cluster compound 9-(pyridine)-11-iodo-decahydro-7,8-dicarba-nido-undecaborane [9-C₅H₅N-11-I-7,8-C₂B₉H₁₀] has been performed. Crystal data: C₇H₁₅B₉NI, M = 337.39, monoclinic, space group P2₁/c, unit cell parameters: a = 9.348(1) Å, b = 11.159(1) Å, c = 13.442(2) Å, β = 98.13(1)°, V = 1388.1(5) ų, Z = 4, d _calc = 1.614 g/cm³, T = 295 K, F(000) = 648, μ = 2.276 mm^?1. The structure was solved by a direct method and refined in the full-matrix anisotropic approximation (isotropic for hydrogen atoms) to final agreement factors R ₁ = 0.0254, wR ₂ = 0.0454 for 2437 I _hkl ≥ 2σ_I from 3590 measured I _hkl (an Enraf-Nonius CAD-4 diffractometer, λMoK _α , graphite monochromator, θ/2θ-scanning). The molecules are joined into a supramolecular assembly by hydrogen bonds X-H?I (X = B, C).     

Encapsulating property of ap-t-butylcalix[6]arene derivative: Formation of charge-transfer complexes of alkadienes with iodine in the presence of octopus-type calix[6]arene

This paper deals with the ability ofp-tert-butylcalix[6]arene derivative1, which has six 3,6,9-trioxadecyl substituents at the phenolic oxygens, to encapsulate CT complexes of alkadienes with iodine. By adding I₂ to alkadienes in CH₂Cl₂ in the presence of1, the absorbance at 363 nm, which was ascribed to I ₃ ^– ion, increased in the order: 1,5-hexadiene<1,9-decadiene 1,7-octadiene. The reactivity features of the CT complexes in the presence of1 are discussed.     

Iodine(III)-mediated aromatic amidation vs olefin amidohydroxylation. The amide N-substituent makes the difference

A series of N-methoxy- and N-para-methoxyphenylacetamides simultaneously substituted at the α position by a benzyl and an allyl group have been treated with phenyliodine(III)bis(trifluoroacetate) to generate stabilized N-acylnitrenium intermediates. It has been observed that, when starting from N-methoxy substituted amides, such intermediates are intramolecularly trapped by nucleophilic arene rings to render the quinolinone skeleton. Alternatively, under the same reaction conditions, N-para-methoxyphenylamides afford pyrrolidinone derivatives through an olefin amidohydroxylation process.     

Der erste Polyiodokomplex – Triethylsulfoniumtriiodomercurat(II)-tris(diiod), (Et3S)[Hg2I6]1/2 · 3 I2

The First Polyiodo Complex – Triethylsulfoniumtriiodomercurate(II)-tris(diiodine), (Et₃S)[Hg₂I₆]_1/2 · 3 I₂ After Raman spectroscopic investigation of the system HgI₂/Et₃SI_x, x = 3, 5, 7, triethylsulfoniumtriiodomercuratetris(diiodine), (Et₃S)[Hg₂I₆]_1/2 · 3 I₂ was synthesized by reacting of HgI₂ and liquid Et₃SI₇. The compound crystallizes at room temperature triclinically in the space group P1 with a = 879.4(7), b = 1 209.1(5), c = 1 291.5(5) pm, α = 96.16(3)°, β = 103.82(6)°, γ = 99.05(5)° and Z = 2. The crystal structure is composed of disordered Et₃S⁺ cations, the centrosymmetric complex anion [HgI_2/2I₂]₂^2? and three connecting iodine molecules I₂.     

The Selection of the Optimal Impregnation Conditions of Vegetable Matrices with Iodine

This study aimed to determine the use of selected vegetables (pumpkin, cauliflower, broccoli, carrot) as carriers of potassium iodide (KI) and potassium iodate (KIO₃) by determining changes in iodine content under various conditions of impregnation as the degree of hydration, impregnated sample temperature, and impregnation time. The influence of these conditions on iodine contents in vegetables after their fortification and storage (21 °C/230 days) was analyzed. The results showed that all selected vegetables could be efficient iodine carriers. However, the conditions of the impregnation process are crucial for fortification efficiency, particularly the degree of hydration and the temperature of the impregnated samples before drying. The results showed that the lowest iodine content was in samples fortified at 4 °C and 1:4 hydration. On the other hand, the highest reproducibility of iodine was for the following fortification conditions: temperature of −76 °C and hydration of 1:1. The studies confirmed the higher stability of iodine in KIO₃ form compared to KI. To increase recovery of the introduced iodine in the product after drying, using the conditioning step at 4 °C is not recommended. We recommend freezing vegetables immediately after the impregnation process     

碘、氟、硅与人体健康的关系

碘、氟、硅是人体必需微量元素,它们的摄入量对人体健康起着重要作用。对碘、氟、硅的缺乏与疾病之间的关系进行了讨论,并对其治疗和防治方法作了介绍。