Characterization of Imidazolium Chloride Ionic Liquids Plus Trivalent Chromium Chloride for Chromium Electroplating

A series of mixtures consisting of the ionic liquids (ILs) 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, and 1-hexyl-3-methylimidazolium chloride ([emim]­[Cl], [bmim]­[Cl], and [hmim]­[Cl], respectively) and trivalent chromium chloride have been prepared. Physicochemical and electrochemical properties of these mixtures have been studied and the potential applications of these mixtures for chromium electroplating, as an alternative to the conventional hard chromium electroplating processes using hexavalent chromium baths, have been examined. To optimize the transport properties of the mixtures, different amounts of ultrapure water were added to the Cr­(III) salt–IL mixtures, although the ultimate goal is to reduce or eliminate water. As shown previously for choline chloride/Cr­(III) salt mixtures, we found that the physicochemical and electrochemical properties of the mixtures are affected by the relative water content. Our preliminary electroplating results show that these types of Cr­(III) salt–IL mixtures could be promising alternatives to Cr­(VI) containing baths for chromium electroplating applications with the advantage of avoiding the use of highly toxic hexavalent chromium

Effect of Structure on Transport Properties (Viscosity, Ionic Conductivity, and Self-Diffusion Coefficient) of Aprotic Heterocyclic Anion (AHA) Room-Temperature Ionic Liquids. 1. Variation of Anionic Species

A series of room temperature ionic liquids (RTILs) based on 1-ethyl-3-methylimidazolium ([emim]⁺) with different aprotic heterocyclic anions (AHAs) were synthesized and characterized as potential electrolyte candidates for lithium ion batteries. The density and transport properties of these ILs were measured over the temperature range between 283.15 and 343.15 K at ambient pressure. The temperature dependence of the transport properties (viscosity, ionic conductivity, self-diffusion coefficient, and molar conductivity) is fit well by the Vogel–Fulcher–Tamman (VFT) equation. The best-fit VFT parameters, as well as linear fits to the density, are reported. The ionicity of these ILs was quantified by the ratio of the molar conductivity obtained from the ionic conductivity and molar concentration to that calculated from the self-diffusion coefficients using the Nernst–Einstein equation. The results of this study, which is based on ILs composed of both a planar cation and planar anions, show that many of the [emim]­[AHA] ILs exhibit very good conductivity for their viscosities and provide insight into the design of ILs with enhanced dynamics that may be suitable for electrolyte applications

Effect of Structure on Transport Properties (Viscosity, Ionic Conductivity, and Self-Diffusion Coefficient) of Aprotic Heterocyclic Anion (AHA) Room Temperature Ionic Liquids. 2. Variation of Alkyl Chain Length in the Phosphonium Cation

A series of room-temperature ionic liquids (ILs) composed of triethyl­(alkyl)­phosphonium cations paired with three different aprotic heterocyclic anions (AHAs) (alkyl = butyl ([P₂₂₂₄]⁺) and octyl ([P₂₂₂₈]⁺)) were prepared to investigate the effect of cationic alkyl chain length on transport properties. The transport properties and density of these ILs were measured from 283.15 to 343.15 K at ambient pressure. The dependence of the transport properties (viscosity, ionic conductivity, diffusivity, and molar conductivity) on temperature can be described by the Vogel–Fulcher–Tamman (VFT) equation. The ratio of the molar conductivity obtained from the molar concentration and ionic conductivity measurements to that calculated from self-diffusion coefficients (measured by pulsed gradient spin–echo nuclear magnetic resonance spectroscopy) using the Nernst–Einstein equation was used to quantify the ionicity of these ILs. The molar conductivity ratio decreases with increasing number of carbon atoms in the alkyl chain, indicating that the reduced Coulombic interactions resulting from lower density are more than balanced by the increased van der Waals interactions between the alkyl chains. The results of this study may provide insight into the design of ILs with enhanced dynamics that may be suitable as electrolytes in lithium ion batteries and other electrochemical applications

Switching the Reaction Course of Electrochemical CO₂ Reduction with Ionic Liquids

The ionic liquid 1-ethyl-3-methylimidazolium bis­(trifluoromethylsulfonyl)­imide ([emim]­[Tf₂N]) offers new ways to modulate the electrochemical reduction of carbon dioxide. [emim]­[Tf₂N], when present as the supporting electrolyte in acetonitrile, decreases the reduction overpotential at a Pb electrode by 0.18 V as compared to tetraethylammonium perchlorate as the supporting electrolyte. More interestingly, the ionic liquid shifts the reaction course during the electrochemical reduction of carbon dioxide by promoting the formation of carbon monoxide instead of oxalate anion. With increasing concentration of [emim]­[Tf₂N], a carboxylate species with reduced CO₂ covalently bonded to the imidazolium ring is formed along with carbon monoxide. The results highlight the catalytic effects of the medium in modulating the CO₂ reduction products

Confocal laser images of wild-type, G615V and C201F LDLR localization in transfected HEK-293 cells.

<p>Cells were incubated with tetramethylrhodamine-conjugated concanavalin A at room temperature for 1 hour. Overlays are shown in the right panels with co-localization appearing yellow. Similar results were obtained in 3 separate experiments.</p

The DNA sequencing results of the two FH probands.

<p>(A) The <i>LDLR</i> gene of proband 1. The arrow indicates the G>T missense mutation at position 1907 of the thirteenth exon resulting in a glycine to valine substitution; (B) The <i>LDLR</i> gene of proband 2. The arrow indicates the G>T missense mutation at position 665 of the fourth exon resulting in a cysteine to phenylalanine substitution.</p

Flow cytometric measurements of wild-type and mutant LDLR internalization activity in transfected HEK-293 cells.

<p>The transfected cells were incubated in serum-free media containing 20 μg/ml Dil-LDL at 37°C for 4 hours. The upper-right area of the dot plots represents EGFP and LDLR double positive cells. (A) Transfected with wild-type; (B) Transfected with the G615V mutant LDLR; (C) Transfected with the C201F mutant LDLR; (D) The histogram shows the percentage of fluorescence for each of the mutations relative to wild-type LDLR. The results are representative of the means ± SD for three independent experiments.</p

Confocal laser images of wild-type, G615V and C201F LDLR activity in transfected HEK-293 cells.

<p>Cells were incubated with 1,1′-dioctadecyl-3,3,3′3′-tetramethylindocarbocyanine perchlorate (Dil)-conjugated LDL for 4 hours at 37°C. Overlays are shown in the right panels with co-localization appearing yellow. Similar results were obtained in 3 separate experiments.</p

Flow cytometric measurements of wild-type and mutatant LDLR expression in transfected HEK-293 cells.

<p>The cells were incubated with phycoerythrin (PE)-conjugated mouse monoclonal anti-human LDLR antibody at room temperature for 30 minutes. The upper right area of the dot plots represents EGFP and LDLR double positive cells. (A) Transfected with wild-type; (B) Transfected with the G615V mutant LDLR; (C) Transfected with the C201F mutant LDLR; (D) The histogram shows the percentage of fluorescence for each of the mutations relative to wild-type. The results are representative of the means ± SD for three independent experiments.</p

Clinical features and gene identification results of the probands and their first relatives.

<p>Clinical features and gene identification results of the probands and their first relatives.</p