Na7I2(OH)5: Ein Hydroxidiodid im System NaOH/NaI

Na₇I₂(OH)₅: A Hydroxide Iodide in the System NaOH/NaI The pseudobinary system NaOH/NaI is investigated by X-ray methods. The crystal structure of the compound Na₇I₂(OH)₅ was solved by single crystal data: Na₇I₂(OH)₅: P4/nmm, Z = 2, a = 7.748(2) Å, c = 10.260(3) Å, Z(F_o) = 443 with (F_o)² ≥ 3σ(F_o)², Z(parameter) = 28, R/R_w = 0.044/0.059 Na₇I₂(OH)₅ crystallizes in a new type of structure which contains puckered layers of ∞²[Na₇(OH)₅²⁺] connected via iodide ions.     

Bis(2‐chloro‐N‐methyl­pyridinium) iodide triiodide

The title compound, 2C₆H₇ClN⁺·I^?·I₃^?, crystallizes with undulating layers of chains containing alternate iodide and triiodide anions formed from iodine and the heterocyclic iodide salt.     

碱金属碘化物与冠醚或穴醚的配合物中I3-和I-的氧化还原行为及其在染料敏化纳米薄膜太阳电池中的应用研究

本文利用超微铂电极和循环伏安法研究了在碱金属碘化物与冠醚或穴醚配合物的3-甲氧基丙腈(MePN)溶液中I₃^-和I^-的氧化还原行为。发现I₃^-和I^-在其中的表观扩散系数与阳离子有关，且I₃^-的表观扩散系数符合以下规律：1,2-二甲基-3-丙基咪唑阳离子(DMPI⁺)> [Na(¯¯15-C-5]⁺ > [K(¯¯18-C-6]⁺ > [Na(¯¯2.2.1-cryptand]⁺，I^-的表观扩散系数则为：[Na(¯¯2.2.1-cryptand]⁺> [Na(¯¯15-C-5]⁺ ≈[K(¯¯18-C-6]⁺> DMPI⁺。比较了由上述配合物和1,2-二甲基-3-丙基咪唑碘(DMPII)组成的染料敏化纳米薄膜太阳电池(DSC)的光伏性能，结果表明由上述配合物组成的DSC，其短路电流略高于DMPII，填充因子略低于DMPII，这与I^-和I₃^-在其中的表观扩散系数的大小是相一致的。此外，电解质溶液中的溶剂对DSC的光电转换效率也有较大影响，以MePN为溶剂，含DMPII的DSC的光电转换效率要高于[K(¯¯18-C-6]I，而以乙腈为溶剂，两者的光电转换效率并没有明显的差别。     

Mapping the Interactions of I2, I., I−, and I+ with Alkynes and Their Roles in Iodocyclizations

A combination of experiment and theory has been used to explore the mechanisms by which molecular iodine (I₂) and iodonium ions (I⁺) activate alkynes towards iodocyclization. Also included in the analysis are the roles of atomic iodine (I ^. ) and iodide ion (I^?) in mediating the competing addition of I₂ to the alkyne. These studies show that I₂ forms a bridged I₂–alkyne complex, in which both alkyne carbons are activated towards nucleophilic attack, even for quite polarized alkynes. By contrast, I⁺ gives unsymmetrical, open iodovinyl cations, in which only one carbon is activated toward nucleophilic attack, especially for polarized alkynes. Addition of I₂ to alkynes competes with iodocyclization, but is reversible. This fact, together with the capacity of I₂ to activate both alkyne carbons towards nucleophilic attack, makes I₂ the reagent of choice (superior to iodonium reagents) for iodocyclizations of resistant substrates. The differences in the nature of the activated intermediate formed with I₂ versus I⁺ can also be exploited to accomplish reagent‐controlled 5‐exo/6‐endo‐divergent iodocyclizations.     

Rotating-disc electrode studies of the anodic oxidation of iodide in concentrated iodine + iodide solutions

The anodic oxidation of iodide on platinum in concentrated iodine + iodide solutions has been investigated using a rotating disc electrode. The conventional limiting diffusion current, which is produced by the diffusion of iodide ions towards the electrode, was not observed due to the formation of an iodine film on the electrode. On the other hand, the steady-state anodic current after a current/time transient is the genuine limiting diffusion current in the anodic oxidation due to diffusion of iodine species from the electrode surface towards the bulk solution. Thus, the dissolution-diffusion control mechanism of the iodine film is confirmed. This is interesting as a typical example of an anodic process in a redox system governed by diffusion of the anodic product species from the electrode surface towards the bulk solution. When an iodine film is formed on the electrode, the maximum driving force of the iodine species is Δm_I2,max, which is defined as the extent of unsaturation of the iodine, and the limiting current of the anodic oxidation of iodide is always directly proportional to Δm_I2,max, regardless of the forms of iodine species in the solution, which may be I₂, I⁻₃, i₅⁻, etc. δm_I2,max is clearly determined by the solution composition and temperature, and it is different in definition and value from the usual degree of unsaturation of iodine.     

Eine neue und unerwartete Form des Dodecaiodid-Ions I122–: Darstellung und Kristallstruktur des Bis[kalium(dibenzo-18-krone-6)]dodecaiodids [K(C20H24O6)]2I12

Studies of Polyhalides. 32. A New and Unforeseen Shape of the Dodecaiodide Ion I₁₂^2–: Preparation and Crystal Structure of Bis[potassium(dibenzo-18-crown-6)]dodecaiodide [K(C₂₀H₂₄O₆)]₂I₁₂ Particularly iodine rich polyiodides tend to form extended iodine nets by multiply concatenating iodide or triiodide ions through iodine molecules. Therefore the discovery of a not ramified, nearly isolated dodecaiodide ion I₁₂^2– in the new compound [K(C₂₀H₂₄O₆)]₂I₁₂ seems to be unexpected. This ion may be described as an extraordinary long fragment of the triiodide-iodine chain (I₃^– · I₂)_∞.     

Untersuchungen an Polyhalogeniden. XXVII. Über Tetra(n-propyl)ammoniumpolyiodide (n-Pr4N)In mit n = 3, 5, 7: Darstellung und strukturelle Charakterisierung eines Triiodids (n-Pr4N)I3, eines Pentaiodids (n-Pr4N)I5 und eines Heptaiodids (n-Pr4N)I7

Studies of Polyhalides. 27. On Tetra(n-propyl)ammonium Polyiodides (n-Pr₄N)I_n with n = 3, 5, 7: Preparation and Crystal Structures of a Triiodide (n-Pr₄N)I₃, a Pentaiodide (n-Pr₄N)I₅, and a Heptaiodide (n-Pr₄N)I₇ [(n-C₃H₇)₄N]I₃, [(n-C₃H₇)₄N]I₅ and [(n-C₃H₇)₄N]I₇ have been prepared by the reaction of tetra(n-propyl)ammoniumiodide [(n-C₃H₇)₄N]I with iodine I₂ in ethanol. Their crystal structures have been determined by single crystal X-ray diffraction methods. The triiodide is built up from layers of the quarternary ammonium ions n-Pr₄N⁺ and from two independent differently packed centrosymmetric triiodide ions I₃^? which alternate with each other along [100]. The pentaiodide ion forms slightly puckered almost squared nets perpendicular [001] of iodide ions which are connected with four iodine molecules by secondary bonds. The meshes from twelve iodine atoms include the cations. The centrosymmetric Z-shaped heptaiodide ion is built up from a linear symmetric triiodide ion and two iodine molecules forming twisted rope ladders along [001] which are separated by stacks of cations.     

Untersuchungen an Polyhalogeniden. XXII [1]. Dimethyldiphenylammoniumpolyiodide (Me2Ph2N)In mit n = 3, 13/3, 6, 8: Darstellung und strukturelle Charakterisierung eines Triiodids (Me2Ph2N)I3, Tridecaiodids (Me2Ph2N)3I13, Dodecaiodids (Me2Ph2N)2I12 und Hexadecaiodids (Me2Ph2N)2I16

Studies of Polyhalides. 22. On Dimethyldiphenylammoniumpolyiodides (Me₂Ph₂N)I_n with n = 3, 13/3, 6, and 8: Preparation and Crystal Structures of a Triiodide (Me₂Ph₂N)I₃, Tridecaiodide (Me₂Ph₂N)₃I₁₃, Dodecaiodide (Me₂Ph₂N)₂I₁₂, and Hexadecaiodide (Me₂Ph₂N)₂I₁₆ The new compounds [(CH₃)₂(C₆H₅)₂N]I₃, [(CH₃)₂(C₆H₅)₂N]₃I₁₃, [(CH₃)₂(C₆H₅)₂N]₂I₁₂ and [(CH₃)₂(C₆H₅)₂N]₂I₁₆ have been prepared by the reaction of dimethyldiphenylammonium iodide [(CH₃)₂(C₆H₅)₂N]I with iodine I₂ in ethanol. Their crystal structures have been determined by single crystal X-ray diffraction methods. The structure of the triiodide may be described as a layerlike packing of pairs of nearly linear symmetric anions and tetraedral cations. The tridecaiodide forms zig-zag chains of iodide ions and iodine molecules with the iodide ion also weakly coordinated by two pentaiodide groups. The dodecaiodide is built from two pentaiodide-groups, which are bridged by an iodine molecule and connected with secondary bonds forming double chains. The hexadecaiodide ion forms layers built up from two heptaiodide groups and one iodine molecule. Thus the dimethyldiphenylammonium cation stabilizes a unique series of polyiodides of extraordinary composition and structure.     

Novel Antimony Complexes: [Ph4Sb]4 +[Sb4I16]4− · 2Me2C=O and [Ph4Sb]3 +[Sb5I18]3−

The [Ph₄Sb]₄ ⁺[Sb₄I₁₆]^4– · 2Me₂C=O and [Ph₄Sb]₃ ⁺[Sb₅I₁₈]^3– complexes were synthesized by reacting tetraphenylstibonium salts Ph₄SbX (X = I, OSO₂C₆H₄Me-4) with antimony triiodide in acetone. According to X-ray diffraction data, their tetra- and pentanuclear anions [Sb₄I₁₆]^4– and [Sb₅I₁₈]^3– have cyclic and linear structure, respectively.     

Nonlinear dynamics in the oxidations of substituted thioureas I: The reaction of 4‐methyl‐3‐thiosemicarbazide with acidic iodate [1]

The substituted thiourea, 4‐methyl‐3‐thiosemicarbazide, was oxidized by iodate in acidic medium. In high acid concentrations and in stoichiometric excess of iodate, the reaction displays an induction period followed by the formation of aqueous iodine. In stoichiometric excess of methylthiosemicarbazide and high acid concentration, the reaction shows a transient formation of aqueous iodine. The stoichiometry of the reaction is: 4IO + 3CH₃NHC(S)NHNH₂ + 3H₂O → 4I⁻ + 3SO + 3CH₃NHC(O)NHNH₂ + 6H⁺ (A). Iodine formation is due to the Dushman reaction that produces iodine from iodide formed from the reduction of iodate: IO + 5I⁻ + 6H⁺ → 3I₂(aq) + 3H₂O (B). Transient iodine formation is due to the efficient acid catalysis of the Dushman reaction. The iodine produced in process B is consumed by the methylthiosemicarbazide substrate. The direct reaction of iodine and methylthiosemicarbazide was also studied. It has a stoichiometry of 4I₂(aq) + CH₃NHC(S)NHNH₂ + 5H₂O → 8I⁻ + SO + CH₃NHC(O)NHNH₂ + 10H⁺ (C). The reaction exhibits autoinhibition by iodide and acid. Inhibition by I⁻ is due to the formation of the triiodide species, I, and inhibition by acid is due to the protonation of the sulfur center that deactivates it to further electrophilic attack. In excess iodate conditions, the stoichiometry of the reaction is 8IO + 5CH₃NHC(S)NHNH₂ + H₂O → 4I₂ + 5SO + 5CH₃NHC(O)NHNH₂ + 2H⁺ (D) that is a linear combination of processes A and B. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 193–203, 2000     

Convective Instability of the Limiting Current of the Triiodide Reduction in a Vertical Channel

The instability of the limiting current of the cathodic reaction is studied in the I^– ₃–I^–/Pt system with excess of potassium iodide at the electrode situated at the bottom of a vertical cylindrical channel. Dependence of parameters of the oscillation process on the concentration of electroactive and supporting ions and solution viscosity is analyzed. The deceleration of the transport processes in solutions containing glycerol is shown to be due to a considerable decrease in the triiodide ion diffusion coefficient.     

Crystal and molecular structure of diphenyliodonium triiodide

A new salt diphenyliodonium triiodide (C₁₂H₁₀I₄) was obtained. The [C₁₂H₁₀I⁺][I₃⁻] compound was isolated as red brown crystals and studied by single-crystal X-ray diffraction. The structure of diphenyliodonium triiodide consists of separate, virtually linear I₃⁻ anions and C₁₂H₁₀I⁺ cations. Strong intermolecular anion-anion (I₃⁻…I₃⁻) and anion-cation (I₃⁻…I⁺) interactions in the crystal structure leads to a change in the symmetry of triiodide ions. The complex formation in the system organic cation iodide-elementary iodine was studied by spectrophotometry. The complex composition was found (1: 1), and the stability constant of the complex in chloroform was determined (loggB = 3.91).     

Radiation effects on gaseous iodine at very low concentrations</p> </p>

Summary Exploratory experiments have been carried out to investigate the effects of gamma-radiation on iodine aerosols under various chemical conditions. The results indicate that iodide ions (I^-) in aerosol can be readily oxidized to I₂ and HIO, and some iodide ions may be converted to organic iodine when organic additives are present in the KI solution from which the aerosol is generated. The results also suggest that the chemical transformation of irradiated iodine aerosol depends on the chemical environment both carrier gas and iodide solution.</p> </p>     

Über die Decamethylferroceniumpolyiodide [(Me5C5)2Fe]Ix mit x = 3, 5 und 6,5. Darstellung und strukturelle Charakterisierung eines Triiodids (DMFc)I3, eines Pentaiodids (DMFc)I5 und eines Hexacosaiodids (DMFc)4I26

Studies on Polyhalides. 30 On Decamethylferriciniumpolyiodides [(Me₅C₅)₂Fe]I_x with x = 3, 5, 6.5: Preparation and Crystal Structures of a Triiodide (DMFc)I₃, a Pentaiodide (DMFc)I₅ and a Hexacosaiodide (DMFc)₄I₂₆ Decamethylferrocene (DMFc) may be oxidized by iodine analogous to ferrocene (Fc) to the decamethylferrocenium ion (DMFc)⁺ and precipitated as the crystalline solids decamethylferrocenium triiodide (DMFc)I₃, decamethylferrocenium pentaiodide (DMFc)I₅ and tetracisdecamethylferrocenium hexacosaiodide (DMFc)₄I₂₆. The two compounds with higher iodine content are new. These are characterized by X-ray diffraction methods on single crystals. The structures are built up from complex cations of expected geometry and isolated or remarkably connected polyiodide ions. Decamethylferrocenium triiodide C₂₀H₃₀FeI₃ crystallizes monoclinically in C2/m with a = 1489.9(4) pm, b = 1133.0(2) pm, c = 765.9(3) pm, β = 111.76(3)° and Z = 2. The crystal structure follows the CsCl-type and contains isolated triiodide ions of the linear symmetric form. Decamethylferrocenium pentaiodide C₂₀H₃₀FeI₅ crystallizes monoclinically in P2₁/c with a = 1130.0(2) pm, b = 1442.6(1) pm, c = 1716.6(2) pm, β = 96.62(1)° and Z = 4. The crystal structure may be deduced from the primitiv quadratic bundle of alternating cationic and anionic rods. It contains exceptionally isolated somewhat opened out pentaiodide ions. Tetrakisdecamethylferrocenium hexacosaiodide (C₂₀H₃₀Fe)₄I₂₆ crystallises monoclinically in P2₁/n with a = 1331.3(8) pm, b = 1319.4(4) pm, c = 3564(2) pm, β = 90.84(5)° and Z = 2. The crystal structure of this compound with unusual composition may be described as an inclusion compound with channels for the cations. The outstanding anionic grating may be derived from the primitive cubic lattice of iodide ions with iodine bridges on all edges by removing systematically 1/12 of the iodine molecules.     

Isolierte I102−‐Ringe,ein neues Strukturelement in der Polyiodid‐Chemie

The novel compound bis(1,4,7,10‐tetraoxa­cyclo­do­decane)­cadmium(II) decaiodide, [Cd(C₈H₁₆O₄)₂]I₁₀, contains the [Cd(12‐crown‐4)₂]²⁺ complex cation, triiodide ions and iodine mol­ecules. Two triiodide ions and two iodine mol­ecules form isolated twisted I₁₀^2? rings. The geometry of the complex cation is as expected, e.g.d(Cd—O) = 2.366 (4) and 2.394 (4) Å.     

Peculiar properties of sodium lodide in alcohols,acetone, and alcohol-water mixtures at lower temperatures

The enthalpies of solution of sodium iodide in methanol, ethanol and acetone and in mixtures of methanol and ethanol with water were measured over wide ranges of electrolyte concentration and temperature. Standard enthalpies of solution, transfer enthalpies of NaI from alcohols to alcohol-water mixtures, and temperature coefficients of enthalpies of solution have been calculated. Thermodyanmic characteristics of solution and solvation of the Na⁺ and I^– ions in acetone and ethanol were determined at 243–298 K. It is noted that at lower temperatures the disruption of solvent structure by ions is a local effect. The presence of negative solvation of the Na⁺ and I^– ions in alcohol-water mixtures at lower temperatures is demonstrated.     

Complex structure tri- and polyiodides of iodocyclization products of 2-allylthioquinoline

Iodocyclization products of 2-allylthioquinoline are obtained in the form of polyiodides with different stoichiometric compositions. X-ray crystallography data are analyzed for two different crystal structures of 1-iodomethyl-1,2-dihydro[1,3]thiazolo[3,2-a]quinolinium polyiodides: triiodide C₁₂H₁₁INS⁺I ₃ ^? and complex polyiodide 2(C₁₂H₁₁INS⁺I ₃ ^? )·I₂. A comparison is made of the nonbonding interactions of dihydrothiazoloquinolinium with atoms of the triiodide anion and complex polyiodide to show the crystal structure features attributed to the participation of molecular iodine.     

Studies on ion exchange equilibria and kinetics VI. Prediction of ion exchange equilibria of UO 2 2+ −Na+−H+ ternary system

Experimental data are reported for the ion exchange equilibria of the binary systems UO ₂ ²⁺ –H⁺, UO ₂ ²⁺ –Na⁺ and Na⁺–H⁺, and of the ternary system UO ₂ ²⁺ –Na⁺–H⁺ on a strong acid cation exchange resin 001X7 at 25 °C. It is found that the equilibria for any pairs of ions are essentially the same in binary and ternary mixtures and that the prediction method proposed by our laboratory for SO ₂ ^2– –Cl^––NO ₃ ^– -201X7 strong base anion exchange resin system is also applicable to the ternary system studied in this paper. The predictions of the ternary system UO ₂ ²⁺ –Na⁺–H⁺ based solely on the binary data without using resin phase activity coefficients are consistent with the experimental data.     

Zur Struktur zweier Isothiazolium‐Polyiodide (C19H16FeNS)I5 und (C15H12NS)2I8

On the Structure of Two Isothiazolium Polyiodides (C₁₉H₁₆FeNS)I₅ and (C₁₅H₁₂NS)₂I₈ By oxidation of 3‐phenylamino thiopropenones with iodine two isothiazolium polyiodides were obtained, whose structures have been determined by X‐ray structure analysis. 2‐Phenyl‐5‐ferrocenyl‐isothiazolium pentaiodide(C₁₉H₁₆FeNS)I₅ forms a layer structure with isothiazolium cations and polyiodide anions. The polyiodide layers contain pentaiodide ions I₅^–, triiodide ions I₃^– and iodine molecules I₂. Bis(2,5‐diphenyl‐isothiazolium) octaiodide (C₁₅H₁₂NS)₂I₈ also forms a layer structure with isothiazolium cations and polyiodide anions. The polyiodide layers are built up by octaiodide ions I₈^2–, pentaiodide ions I₅^– and triiodide ions I₃^–.     

High-capacity NO2 denuder systems operated at various temperatures (298–473?K)

In this study, we investigated several coatings for high-temperature, high-capacity, and high-efficiency denuder-based NO₂ removal, with the scope to face the harsh conditions and requirements of automotive exhaust gas sampling. As first coating, we propose a potassium iodide (KI)/polyethylene glycol coating with a high removal efficiency (ε?>?98?%) for about 2?h and 50?ppm NO₂ at room temperature (298?K). At elevated temperatures (423?K), the initial capacity (100?ppmh) is decreased to 15?ppmh. Furthermore, this is the first proposal of the ionic liquid methyl-butyl-imidazolium iodide ([BMIm⁺][I^?]) as denuder coating material. At room temperature, this ionic liquid exhibits far greater capacity (300?ppmh) and NO₂ removal efficiency (ε?>?99.9?%) than KI. Nevertheless, KI exhibits a slightly (~10?%) higher capacity at elevated temperatures than [BMIm⁺][I^?]. Both coatings presented are suitable for applications requiring selective denuding of NO₂ at temperatures up to 423?K.