Electrical,optical and photoelectrochemical studies on a solid PEO-polymer electrolyte doped with low viscosity ionic liquid

Solid polymer electrolyte (PEO:KI:I₂) membranes doped with low viscosity (34 cP at 25 °C) ionic liquid EMImTFSI (1-ethyl 3-methylimidazolium bis(trifluoromethylsulfonyl)imide) showing plasticizing effect as well as improved dye sensitized solar cell efficiency have been reported first time. Apart from ionic conductivity enhancement due to large number of free charge carriers provided by ionic liquid (IL) it assist in reducing cystallinity of polymer electrolyte matrix which was confirmed by polarized optical microscopy (POM). Cyclic voltammetry was carried out to study the reactions of iodide, iodine and IL in polymer electrolyte matrix.     

Reactions of a Polyhalide Ionic Liquid with Copper,Silver, and Gold

The reactions of copper, silver, and gold with the imidazolium-based polyhalide ionic liquid (IL) [C₆C₁Im][Br₂I] were investigated by using X-ray photoelectron spectroscopy (XPS), weight-loss measurements, and gas-phase mass spectrometry. All three Group 11 metals are strongly corroded by the IL at moderate temperatures to give a very high content of dissolved Cu^I, Ag^I, and Au^I species. The IL–metal solutions are stable against contact with water and air. The replacement of imidazolium with inorganic sodium cations decreased metal corrosion rates by orders of magnitude. Our results clearly indicate metal oxidation by iodide from dibromoiodide anions to form molecular iodine and anionic [Br-M^I-Br]⁻ (M=Cu, Ag, Au) complexes stabilized by imidazolium counterions. From experiments with a trihalide IL with imidazolium methylated at the 2-position, we ruled out the formation of imidazole–carbene as a cause of the observed corrosion. In contrast to Group 11 metals, molybdenum is inert against the trihalide IL, which is attributed to surface passivation.     

一种新型有机硅离子液体电解液在超级电容中的应用

设计合成了一种新型有机硅室温离子液体(SiN1IL), 并对其化学结构和电化学窗口进行表征, 通过与具有高介电常数的丙烯碳酸酯(PC)/低粘度的乙腈(AN)匹配组成电解液, 其离子电导率达到商业实际应用的要求(19.6 mS·cm^-1). 对以活性炭(AC)为对称电极的超级电容器的电化学性能测试表明, SiN1IL 基电解液与活性炭有很好的界面相容性, 其高倍率充放电、阻抗性能优于商用四乙基四氟硼酸铵(Et₄NBF₄)/PC 电解液, 在电流密度为1000 mA·g^-1的条件下, 工作电压为2.7 V, 其比电容为108 F·g^-1.     

Synthesis and Structure of Trimethylplatinum(IV) Iodide Complex of 4'-(4-Methoxyphenyl)-2,2':6',2'-terpyridine Ligand and its Halogen Bonding Property

The synthesis and structural characterization of a new trimethylplatinum(IV) iodide complex of 4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine ligand L, {PtMe₃IL} ( 1 ) is reported. The X-ray crystal structure shows that the terpyridine ligand L binds the platinum(IV) metal center in bidentate fashion, which is well supported by the ¹H NMR spectrum of 1 . The complex 1 upon crystallization with 1,4-diiodotetrafluorobenzene (DITFB) forms the halogen bonded complex 1a ( 1· DITFB). The structural investigation shows that 1a exhibits the halogen bonding interaction in which the non-coordinated pyridyl nitrogen acts as halogen bond acceptors by forming I ··· N interaction with iodine atom of DITFB. In addition iodine atom of complex 1 also acts as weak halogen bond acceptor.     

Interactions between a dsDNA Oligonucleotide and Imidazolium Chloride Ionic Liquids: Effect of Alkyl Chain Length,Part I

Ionic liquids (ILs) have become nearly ubiquitous solvents and their interactions with biomolecules has been a focus of study. Here, we used the fluorescence emission of DAPI, a groove binding fluorophore, coupled with molecular dynamics (MD) simulations to report on interactions between imidazolium chloride ([Im_n,1]⁺) ionic liquids and a synthetic DNA oligonucleotide composed entirely of T/A bases (7(TA)) to elucidate the effects ILs on a model DNA duplex. Spectral shifts on the order of 500–1000 cm⁻¹, spectral broadening (~1000 cm⁻¹), and excitation and emission intensity ratio changes combine to give evidence of an increased DAPI environment heterogeneity on added IL. Fluorescence lifetimes for DAPI/IL solutions yielded two time constants 0.15 ns (~80% to 60% contribution) and 2.36–2.71 ns for IL up to 250 mM. With DNA, three time constants were required that varied with added IL (0.33–0.15 ns (1–58% contribution), ~1.7–1.0 ns (~5% contribution), and 3.8–3.6 ns (94–39% contribution)). MD radial distribution functions revealed that π-π stacking interactions between the imidazolium ring were dominant at lower IL concentration and that electrostatic and hydrophobic interactions become more prominent as IL concentration increased. Alkyl chain alignment with DNA and IL-IL interactions also varied with IL. Collectively, our data showed that, at low IL concentration, IL was primarily bound to the DNA minor groove and with increased IL concentration the phosphate regions and major groove binding sites were also important contributors to the complete set of IL-DNA duplex interactions.     

Temperature dependence of the microstructure of 1-butyl-3-methylimidazolium tetrafluoroborate in aqueous solution

Many applications of ionic liquids (ILs) are closely related with their microstructure in mixtures. For example, morphology and pore size of the MCM-41 prepared in aqueous ILs are greatly dependent on the aggregation behavior of the ILs in water. Therefore, the study on the microstructure of ILs in aqueous solutions is of great importance. In this work, ¹H NMR, dynamic light scattering and attenuated total reflection infrared spectroscopy have been used to investigate the temperature effect on the structures of aqueous 1-butyl-3-methylimidazolium tetrafluoroborate ([C₄mim][BF₄]) solutions. It was shown that the size of the IL aggregates becomes larger with decreasing temperature. When the system temperature is below the upper critical solution temperature (UCST) of the binary mixture at about 4 °C, the aggregate size of the IL is larger than 1000 nm. Additionally, the two-dimensional IR results reveal that at low IL concentrations, H₂O can interact with [BF₄]⁻ prior to the CH groups of the imidazolium ring, whereas cation and anion of the IL tend to form aggregate at high IL concentrations. With the decrease of temperature, the interactions between cation and anion of the IL become stronger, but those between the IL and water become weaker, thereby resulting in the growth of the aggregate of cation with anion of the IL. This result may give a reasonable explanation for the origin of the UCST behavior of aqueous [C₄mim][BF₄] solution.     

Photolytic cage effect of iodine in gases at high pressures

The photolysis of iodine has been studied in the gas phase using laser flash photolysis at 6943 A. The dependence of the quantum yield on the pressure has been investigated in the range 0.1–1000 atm for several inert gases. For Kr, Xe, O₂, CO₂, CH₄, C₂H₆ and C₃H₈ a decrease of the quantum yield with increasing pressure was obtained; for He, Ne, Ar and H₂ no effect could be observed. These results may correspond to a photolycitc cage effect of iodine in the gas phase analogous to that known from the liquid phase.     

Determining the chromophore in the amylopectin–iodine complex by theoretical and experimental studies

A partial hydrolysis of amylose followed by the addition of iodine provides a spectrum almost identical to that of the amylopectin–iodine (API) complex suggesting the involvement of smaller “amylose-like” units in the API complex. Our theoretical studies on different polyiodine and polyiodide species suggest that a nearly linear I₄ unit stabilized within the cavity of a small “amylose-like” helix is responsible for the characteristic API spectrum. Since there are 2.75 anhydroglucose residues (AGU) for every iodine atom in the amylose–iodine (AI) complex and a structural similarity exists between the API and the AI (amylose–iodine) complexes, we identify (C₆H₁₀O₅)₁₁I₄ to be the chromophore in the API complex. © 1994 John Wiley & Sons, Inc.     

Breaking Mass Transport Limitations by Iodized Polyacrylonitrile Anodes for Extremely Fast-Charging Lithium-Ion Batteries

The fast-charging capability of rechargeable batteries is greatly limited by the sluggish ion transport kinetics in anode materials. Here we develop an iodized polyacrylonitrile (I-PAN) anode that can boost the bulk/interphase lithium (Li)-ion diffusion kinetics and accelerate Li-ion desolvation process to realize high-performance fast-charging Li-ion batteries. The iodine immobilized in I-PAN framework expands ion transport channels, compresses the electric double layer, and changes the inner Helmholtz plane to form LiF/LiI-rich solid electrolyte interphase layer. The dissolved iodine ions in the electrolyte self-induced by the interfacial nucleophilic substitution of PF₆⁻ not only promote the Li-ion desolvation process, but also reuse the plated/dead Li formed on the anode under fast-charging conditions. Consequently, the I-PAN anode exhibits a high capacity of 228.5 mAh g⁻¹ (39 % of capacity at 0.5 A g⁻¹ delivered in 18 seconds) and negligible capacity decay for 10000 cycles at 20 A g⁻¹. The I-PAN||LiNi_0.8Co_0.1Mn_0.1O₂ full cell shows excellent fast-charging performance with attractive capacities and negligible capacity decay for 1000 cycles at extremely high rates of 5 C and 10 C (1 C=180 mA g⁻¹). We also demonstrate high-performance fast-charging sodium-ion batteries using I-PAN anodes.     

Iodine binding capacity and iodine binding energy of glycogen

The iodine binding capacity (IBC) of glycogen is around 0.30% (w/w) at 3°C. The amount of iodine complexed comprises about 12.5% of the mass of glycogen that takes part in the glycogen–iodine (GI) complex formation. This suggests involvement of four iodine atoms for every 25 anhydroglucose units (AGU, C₆H₁₀O₅). Since the chromophore is due to the I₄ unit within the helix of 11 AGUs, only 44% of the AGUs (11 out of 25) are involved in the complex formation. The heat of formation of the GI complex is around −40 kJ/mol of I₂ bonded. These results suggest remarkable similarities with those of the amylopectin–iodine (API) complex. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1409–1412, 1997     

A green procedure for the protection of carbonyl compounds catalyzed by iodine in ionic liquid

Aldehydes and ketones are protected with ethylene glycol in the presence of a catalytic amount of iodine in PEG ionic liquid (IL 400) under mild conditions to afford the corresponding ketals in good yields. The recovery of iodine is facilitated by the ionic liquid. The recovered catalyst was reused six times with consistent activity.     

Reactivity of main grouptransmittion metal bonds : III. Reactions of halogens with Ph3SiMn(CO)5 and Ph3SnMn(CO)5

The products of the reaction of Ph₃MMn(CO)₅ (M = Si or Sn) with chlorine, bromine and iodine in tetrachloromethane, have been determined.Ph₃SiMn(CO)₅ does not react with iodine, and the SiMn bond is cleaved by chlorine and by bromine.Ph₃SnMn(CO)₅ reacts in a much more complex manner, PhSn bond cleavage occurring with all three halogens to give mono-, di-, and, with the exception of iodine, tri-halogenated derivatives. Bromine, in high concentration, and iodine also cleave the SnMn bond.     

Microwave Irradiation for the Facile Synthesis of Transition‐Metal Nanoparticles (NPs) in Ionic Liquids (ILs) from Metal–Carbonyl Precursors and Ru‐, Rh‐, and Ir‐NP/IL Dispersions as Biphasic Liquid–Liquid Hydrogenation Nanocatalysts for Cyclohexene

Stable chromium, molybdenum, tungsten, manganese, rhenium, ruthenium, osmium, cobalt, rhodium, and iridium metal nanoparticles (M‐NPs) have been reproducibly obtained by facile, rapid (3 min), and energy‐saving 10 W microwave irradiation (MWI) under an argon atmosphere from their metal–carbonyl precursors [M_x(CO)_y] in the ionic liquid (IL) 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([BMIm][BF₄]). This MWI synthesis is compared to UV‐photolytic (1000 W, 15 min) or conventional thermal decomposition (180–250 °C, 6–12 h) of [M_x(CO)_y] in ILs. The MWI‐obtained nanoparticles have a very small (<5 nm) and uniform size and are prepared without any additional stabilizers or capping molecules as long‐term stable M‐NP/IL dispersions (characterization by transmission electron microscopy (TEM), transmission electron diffraction (TED), and dynamic light scattering (DLS)). The ruthenium, rhodium, or iridium nanoparticle/IL dispersions are highly active and easily recyclable catalysts for the biphasic liquid–liquid hydrogenation of cyclohexene to cyclohexane with activities of up to 522 (mol product) (mol Ru)^?1 h^?1 and 884 (mol product) (mol Rh)^?1 h^?1 and give almost quantitative conversion within 2 h at 10 bar H₂ and 90 °C. Catalyst poisoning experiments with CS₂ (0.05 equiv per Ru) suggest a heterogeneous surface catalysis of Ru‐NPs.     

The Photochemistry of Ch3I in Various Matrices at Low Temperature

The photodissociation of methyl iodide in various matrices at low temperature was studied. The observed Raman spectra excited by 514.5 nm laser radiation showed that there were two different photolytically produced iodine species isolated in the matrices after illumination by a medium pressure mercury lamp. One species which was dominant at lower iodine concentrations and exhibited a progression with an ωe of 201 cm^?1, belonged to the matrix isolated iodine monomer (I₂). The other species, which was dominant at higher iodine concentrations with an ω_e of approximately 180 cm^?1, belonged to the iodine aggregate ((I₂)_n). Five progressions of resonance Raman or resonance fluorescence of these two species were also observed in the other matrices. The iodine aggregate in the methyl iodide matrix at 77 K was formed in a crystalline structure, while the photolytically generated iodine aggregate from CH₃I/Ar (2/3) matrix at 10 K, after illumination with a mercury lamp, was in amorphous form. The rearrangement of photolytically produced iodine aggregate in methyl iodide matrix was observed as a function of the duration of illumination. Local heating effects of the laser radiation might induce the iodine monomer to aggregate in matrices. The photodissociation mechanism of methyl iodide in matrices is also proposed.     

Excessive Iodine Enabled Ultrathin Inorganic Perovskite Growth at the Liquid-Air Interface

The liquid-air interface offers a platform for the in-plane growth of free-standing materials. However, it is rarely used for inorganic perovskites and ultrathin non-layered perovskites. Herein the liquid-air interfacial synthesis of inorganic perovskite nanosheets (Cs₃Bi₂I₉, Cs₃Sb₂I₉) is achieved simply by drop-casting the precursor solution with only the addition of iodine. The products are inaccessible without iodine addition. The thickness and lateral size of these nanosheets can be adjusted through the iodine concentration. The high volatility of the iodine spontaneously drives precursors that normally stay in the liquid to the liquid-air interface. The iodine also repairs in situ iodine vacancies during perovskite growth, giving enhanced optical and optoelectronic properties. The liquid-air interfacial growth of ultrathin perovskites provides multi-degree-of-freedom for constructing perovskite-based heterostructures and devices at atomic scale.     

Reaction of (diacetoxyiodo)benzene with excess of trifluoromethanesulfonic acid. A convenient route to para-phenylene type hypervalent iodine oligomers

Reaction of (diacetoxyiodo)benzene [PhI(OAc)₂] in trifluoromethanesulfonic acid (TfOH) resulted in oligomerization of PhI(OAc)₂. Quenching with NaBr gave the bromide salts of hypervalent iodine oligomers that were determined by thermolysis with KI to be a para phenylene type of oligomers. Neutralization of the reaction mixture of PhI(OAc)₂ and TfOH with aqueous NaHCO₃ yielded the triflate salts of iodine oligomers. Furthermore, quenching the reaction mixture with aromatic substrates afforded arylated iodine oligomers. These iodine oligomers were found to be 3-4 of the number average degree of polymerization (P_n) by GC analysis of the thermolysis products and ¹H NMR analysis. The major products, trimer and tetramer, were synthesized independently.     

Verflüchtigung von Spaltproduktjod aus Festem UCl4

It is possible to volatilize about 95% (at temperatures between 200°C and 600°C) of the iodine, which has been produced by irradiating solid UCl₄ with thermal neutrons. The delay times for iodine are decreasing from 2 hrs (at 200°C) to 7 sec (at 600°C). The release of the iodine is improved by using an inert carrier gas. When adding AgCl to the UCl₄ before irradiation is carried out, the release of iodine is suppressed at temperatures lower than 400°C. The adding of KI leads to a more rapid release of iodine at low temperatures.      

Darstellung neuer Halogeno-kohlenoxid-Komplexe des Eisens

The dicarbonyl complex Fe(CO)₂(TP)I₂ is obtained by CO-substitution of Fe(CO)₄I₂ with 1,1.1-tris(diphenylphosphinomethylene)ethane (TP), in which the tridentate phosphorus ligand functions only bidentate. By a further reaction with iodine the tetraiodo complex Fe(CO)₂(TP)I₄ is formed, in which ever two iodine atoms are bonded to the metal and to the phosphorus. The same compound type is also formed by the oxydation of the trigonal-bipyramidally configurated Fe(CO₂)TP with the halides chlorine, bromine and iodine in a molar ratio 1:2.     

Vernetzte Gleichgewichte: Verhalten von lod gegenüber Petrolether,Wasser und Kaliumiodid

Because of the formation of KI₃, potassium iodide increases the extraction rate of iodine from petroleum ether into water. Nernst's constant of the distribution of iodine in the system water/petroleum ether (KN = 34.1 ± 4.6) and the equilibrium constant of the formation of KI₃ from iodine and potasium (K_K = 820 ± 203 1 · mol⁻¹) are determined by titration of I₂ or KI₃ in the separated organic and aqueous layers with thiosulfate standard solution. Aspects of environmental protection are an integral part of the experiments,e.g. iodine and petroleum ether are recycled.