Formation and Surface Behavior of Pt and Pd Complexes with Ligand Systems Derived from Nitrile-functionalized Ionic Liquids Studied by XPS

We studied the formation and surface behavior of Pt(II) and Pd(II) complexes with ligand systems derived from two nitrile-functionalized ionic liquids (ILs) in solution using angle-resolved X-ray photoelectron spectroscopy (ARXPS). These ligand systems enabled a high solubility of the metal complexes in IL solution. The complexes were prepared by simple ligand substitution under vacuum conditions in defined excess of the coordinating ILs, [C₃CNC₁Im][Tf₂N] and [C₁CNC₁Pip][Tf₂N], to immediately yield solutions of the final products. The ILs differ in the cationic head group and the chain length of the functionalized substituent. Our XPS measurements on the neat ILs gave insights in the electronic properties of the coordinating substituents revealing differences in donation capability and stability of the complexes. Investigations on the composition of the outermost surface layers using ARXPS revealed no surface affinity of the nitrile-functionalized chains in the neat ILs. Solutions of the formed complexes in the nitrile ILs showed homogeneous distribution of the solute at the surface with the heterocyclic moieties preferentially orientated towards the vacuum, while the metal centers are rather located further away from the IL/vacuum interface.     

Speciation of Rare‐Earth Metal Complexes in Ionic Liquids: A Multiple‐Technique Approach

The dissolution process of metal complexes in ionic liquids was investigated by a multiple‐technique approach to reveal the solvate species of the metal in solution. The task‐specific ionic liquid betainium bis(trifluoromethylsulfonyl)imide ([Hbet][Tf₂N]) is able to dissolve stoichiometric amounts of the oxides of the rare‐earth elements. The crystal structures of the compounds [Eu₂(bet)₈(H₂O)₄][Tf₂N]₆, [Eu₂(bet)₈(H₂O)₂][Tf₂N]₆?2H₂O, and [Y₂(bet)₆(H₂O)₄][Tf₂N]₆ were found to consist of dimers. These rare‐earth complexes are well soluble in the ionic liquids [Hbet][Tf₂N] and [C₄mim][Tf₂N] (C₄mim=1‐butyl‐3‐methylimidazolium). The speciation of the metal complexes after dissolution in these ionic liquids was investigated by luminescence spectroscopy, ¹H, ¹³C, and ⁸⁹Y NMR spectroscopy, and by the synchrotron techniques EXAFS (extended X‐ray absorption fine structure) and HEXS (high‐energy X‐ray scattering). The combination of these complementary analytical techniques reveals that the cationic dimers decompose into monomers after dissolution of the complexes in the ionic liquids. Deeper insight into the solution processes of metal compounds is desirable for applications of ionic liquids in the field of electrochemistry, catalysis, and materials chemistry.     

Towards a Molecular Understanding of Cation–Anion Interactions—Probing the Electronic Structure of Imidazolium Ionic Liquids by NMR Spectroscopy,X‐ray Photoelectron Spectroscopy and Theoretical Calculations

Ten [C₈C₁Im]⁺ (1‐methyl‐3‐octylimidazolium)‐based ionic liquids with anions Cl^?, Br^?, I^?, [NO₃]^?, [BF₄]^?, [TfO]^?, [PF₆]^?, [Tf₂N]^?, [Pf₂N]^?, and [FAP]^? (TfO=trifluoromethylsulfonate, Tf₂N=bis(trifluoromethylsulfonyl)imide, Pf₂N=bis(pentafluoroethylsulfonyl)imide, FAP=tris(pentafluoroethyl)trifluorophosphate) and two [C₈C₁C₁Im]⁺ (1,2‐dimethyl‐3‐octylimidazolium)‐based ionic liquids with anions Br^? and [Tf₂N]^? were investigated by using X‐ray photoelectron spectroscopy (XPS), NMR spectroscopy and theoretical calculations. While ¹H NMR spectroscopy is found to probe very specifically the strongest hydrogen‐bond interaction between the hydrogen attached to the C² position and the anion, a comparative XPS study provides first direct experimental evidence for cation–anion charge‐transfer phenomena in ionic liquids as a function of the ionic liquid’s anion. These charge‐transfer effects are found to be surprisingly similar for [C₈C₁Im]⁺ and [C₈C₁C₁Im]⁺ salts of the same anion, which in combination with theoretical calculations leads to the conclusion that hydrogen bonding and charge transfer occur independently from each other, but are both more pronounced for small and more strongly coordinating anions, and are greatly reduced in the case of large and weakly coordinating anions.     

Use of water in aiding olefin/paraffin (liquid + liquid) extraction via complexation with a silver bis(trifluoromethylsulfonyl)imide salt

This paper describes the extraction of C₅–C₈ linear α-olefins from olefin/paraffin mixtures of the same carbon number via a reversible complexation with a silver salt (silver bis(trifluoromethylsulfonyl)imide, Ag[Tf₂N]) to form room temperature ionic liquids [Ag(olefin)_x][Tf₂N]. From the experimental (liquid + liquid) equilibrium data for the olefin/paraffin mixtures and Ag[Tf₂N], 1-pentene showed the best separation performance while C₇ and C₈ olefins could only be separated from the corresponding mixtures on addition of water which also improves the selectivity at lower carbon numbers like the C₅ and C₆, for example. Using infrared and Raman spectroscopy of the complex and Ag[Tf₂N] saturated by olefin, the mechanism of the extraction was found to be based on both chemical complexation and the physical solubility of the olefin in the ionic liquid ([Ag(olefin)_x][Tf₂N]). These experiments further support the use of such extraction techniques for the separation of olefins from paraffins.     

The Temperature Effect on the Transport Properties of 1-Alkyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide Ionic Liquids

The temperature dependences of specific and equivalent conductivities, viscosity, density, and crystallization temperature are determined for three 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([C _n MeIm] [Tf₂N], n = 2, 3, 4) ionic liquids saturated with water vapor at room temperature. It is established that in the area of positive temperatures, the relationship between viscosity and conductivity obeys the fractional Walden rule with exponents of 0.97, 0.92, and 0.92 for ionic liquids with ethyl-, propyl-, butylradicals, respectively. The temperature dependences of conductivity and viscosity are approximated using the Vogel–Fulcher–Tammann equation (R² > 0.999), and ideal glass transition temperatures T₀ are calculated for the investigated liquids. The obtained values of T₀ depend largely on the chosen range of temperatures. It is shown that [C₂MeIm][Tf₂N] occupies a separate position with regard to [C₃MeIm][Tf₂N] and [C₄MeIm][Tf₂N].     

Synthesis and X-ray structure of a highlyhindered N-functionalized alkyl-cobalt(II) complex trans-[Co{[C(SiMe3)2C5H4N-2}2]

The thermally-stable cobalt(II) dialkyl compound CoR₂ [R = C(SiMe₃)₂C₅H₄N-2] (1) has been prepared by reaction of [{LiR}₂] with cobalt(II) chloride in ether. An X-ray structural study has revealed a centrosymmetric molecular skeleton (for two nearly identical independent molecules) in which a pair of sterically-hindered, functionalized pyridine ligands R⁻ are trans-chelated to the central planar four-coordinate cobalt(II) atom, with mean CoC_α and CoN distances of 2.094(6)Å and 1.919(4) Å respectively, and a C_αCoN angle of 69.6(2)°.     

Vapochromic Ionic Liquids from Metal–Chelate Complexes Exhibiting Reversible Changes in Color,Thermal, and Magnetic Properties

Vapor‐ and gas‐responsive ionic liquids (ILs) comprised of cationic metal‐chelate complexes and bis(trifluoromethanesulfonyl)imide (Tf₂N) have been prepared, namely, [Cu(acac)(BuMe₃en)][Tf₂N] ( 1 a ), [Cu(Bu‐acac)(BuMe₃en)][Tf₂N] ( 1 b ), [Cu(C₁₂‐acac)(Me₄en)][Tf₂N] ( 1 c ), [Cu(acac)(Me₄en)][Tf₂N] ( 1 d ), and [Ni(acac)(BuMe₃en)][Tf₂N] ( 2 a ) (acac=acetylacetonate, Bu‐acac=3‐butyl‐2,4‐pentanedionate, C₁₂‐acac=3‐dodecyl‐2,4‐pentanedionate, BuMe₃en=N‐butyl‐N,N′,N′‐tetramethylethylenediamine, and Me₄en=N,N,N′,N′‐trimethylethylenediamine). These ILs exhibited reversible changes in color, thermal properties, and magnetic properties in response to organic vapors and gases. The Cu^II‐containing ILs are purple and turn blue‐purple to green when exposed to organic vapors, such as acetonitrile, methanol, and DMSO, or ammonia gas. The color change is based on the coordination of the vapor molecules to the cation, and the resultant colors depend on the coordination strength (donor number, DN) of the vapor molecules. The vapor absorption caused changes in the melting points and viscosities, leading to alteration in the phase behaviors. The IL with a long alkyl chain ( 1 d ) transitioned from a purple solid to a brown liquid at its melting point. The Ni^II‐containing IL ( 2 a ) is a dark red diamagnetic liquid, which turned into a green paramagnetic liquid by absorbing vapors with high DN. Based on the equilibrium shift from four‐ to six‐coordinated species, the liquid exhibited thermochromism and temperature‐dependent magnetic susceptibility after absorbing methanol.     

Synthesis,Structure, and Physico‐optical Properties of Manganate(II)‐Based Ionic Liquids

Several ionic liquids (ILs) based on complex manganate(II) anions with chloro, bromo, and bis(trifluoromethanesulfonyl)amido (Tf₂N) ligands have been synthesized. As counterions, n‐alkyl‐methylimidazolium (C_nmim) cations of different chain length (alkyl=ethyl (C₂), propyl (C₃), butyl (C₄), hexyl (C₆)) were chosen. Except for the 1‐hexyl‐3‐methylimidazolium ILs, all of the prepared compounds could be obtained in a crystalline state at room temperature. However, each of the compounds displayed a strong tendency to form a supercooled liquid. Generally, solidification via a glass transition took place below ?40 °C. Consequently, all of these compounds can be regarded as ionic liquids. Depending on the local coordination environment of Mn²⁺, green (tetrahedrally coordinated Mn²⁺) or red (octahedrally coordinated Mn²⁺) luminescence emission from the ⁴T(G) level is observed. 1 The local coordination of the luminescent Mn²⁺ centre has been unequivocally established by UV/Vis as well as Raman and IR vibrational spectroscopies. Emission decay times measured at room temperature in the solid state (crystalline or powder) were generally a few ms, although, depending on the ligand, values of up to 25 ms were obtained. For the bromo compounds, the luminescence decay times proved to be almost independent of the physical state and the temperature. However, for the chloro‐ and bis(trifluoromethanesulfonyl)amido ILs, the emission decay times were found to be dependent on the temperature even in the solid state, indicating that the measured values are strongly influenced by nuclear motion and the vibration of the atoms. In the liquid state, the luminescence of tetrahedrally coordinated Mn²⁺ could only be observed when the tetrachloromanganate ILs were diluted with the respective halide ILs. However, for [C₃mim][Mn(Tf₂N)₃], in which Mn²⁺ is in an octahedral coordination environment, a weak red emission from the pure compound was found even in the liquid state at elevated temperatures.     

Kinetic study of the oxidative addition of methyl iodide to Vaska’s complex in ionic liquids

Oxidative addition of methyl iodide to Vaska’s complex in the ionic liquids 1-butyl-3-methylimidazolium triflate [C₄mim][OTf], [C₄mim] bis(trifluormethylsulfonyl)imide [Tf₂N], and N-hexylpyridinium [C₆pyr][Tf₂N] occurred cleanly to give the expected Ir(III) oxidative addition product. Pseudo-first order rate constants were determined for the oxidative addition reaction in each solvent ([Vaska’s] = 0.25 mM, [CH₃I] = 37.5 mM). The observed rate constants under these conditions were 5-10 times slower than the rate seen in DMF. At high methyl iodide concentrations (>23 mM), the expected first order dependence on methyl iodide was not observed. In each ionic liquid, there was no change in the reaction rates within experimental error over the methyl iodide concentration range of 23-75 mM. At lower methyl iodide concentration, a decrease in rate was observed in [C₄mim][Tf₂N] with decreasing concentration of methyl iodide.     

Reactive Half‐Metallocenium Ionic Liquids That Undergo Solventless Ligand Exchange

The piano‐stool half‐metallocenium cations [Fe(C₅R₅)(CO)₂ L ]⁺ (C₅R₅=C₅H₅, C₅Me₅, C₅Me₄Et; L =1‐pentene, nBuCN, MeCN, Me₂S, NH₃, NMe₃, pyridine) provide ionic liquids (ILs) with the bis(trifluoromethanesulfonyl)imide (Tf₂N) anion without introducing long alkyl chains. Their melting points are affected by molecular symmetry, and their thermal stabilities reflect the strength of the metal–ligand bonding. These are reactive liquids that show solventless ligand exchange reactions by gas absorption. The direction of the ligand‐exchange reaction is correlated with the stabilities. Based on the variation of the melting points, these ILs undergo transformations between the liquid and solid phases associated with the reaction.     

以N为中心的阴离子离子液体的合成、表征及应用

首次通过不同阴离子的钾盐和不同的季铵化的咪唑,吡咯溴盐/氯盐进行离子交换,合成了一系列含氰基官能团的阴离子功能化离子液体。通过红外、核磁共振、质谱对离子液体的结构进行表征;通过TGA对离子液体的热稳定性进行测定,结果发现功能化离子液体具有良好的热稳定性,其分解温度在224-289℃范围内。将功能化离子液体[EMIm][N(CN)COC2H5]作为配体应用于无膦配体的Suzuki偶联反应,发现在反应中加入功能化离子液体[EMIm][N(CN)COC2H5]可以使反应收率提高10-20%。     

Expanding the Chemical Space of Benzimidazole Dicationic Ionic Liquids

Benzimidazole dicationic ionic liquids (BDILs) have not yet been widely explored in spite of their potential. Therefore, two structurally related families of BDILs, paired with either bromide or bistriflimide anions and bearing alkyl spacers ranging from C3 to C6, have been prepared. Their thermal properties have been studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), while their electrical properties have been assessed by cyclic voltammetry (CV). TG analysis confirmed the higher stability of the bistriflimide BDILs over the bromide BDILs, with minor variation within the two families. Conversely, DSC and CV allowed for ascertaining the role played by the spacer length. In particular, the thermal behavior changed dramatically among the members of the bistriflimide family, and all three possible thermal behavior types of ILs were observed. Furthermore, cyclic voltammetry showed different electrochemical window (C₃(C₁BenzIm)₂/2Tf₂N < C₄(C₁BenzIm)₂/2Tf₂N, C₅(C₁BenzIm)₂/2Tf₂N < C₆(C₁BenzIm)₂/2Tf₂N) as well as a reduction peak potential, shape, and intensity as a function of the spacer length. The results obtained highlight the benefit of accessing a more structurally diverse pool of compounds offered by dicationic ILs when compared to the parent monocationic ILs. In particular, gains are to be found in the ease of fine-tuning their properties, which translates in facilitating further investigations toward BDILs as designer solvents and catalysts.     

The First Homoleptic Bis(trifluoromethanesulfonyl)amide Complex of Yttrium: [bmim][Y(Tf2N)4]

1‐Butyl‐3‐methylimidazolium tetrakis‐(bis(trifluoromethanesulfonyl)amide)yttrium(III), [bmim][Y(Tf₂N)₄], was obtained from the ionic liquid 1‐butyl‐3‐methylimidazoliumbis(trifluoromethanesulfonyl)amide, [bmim][Tf₂N] and yttrium(III)bis(trifluoromethanesulfonyl)amide, Y(Tf₂N)₃. The crystal structure [monoclinic, C2/c (no. 15), a = 2096.(1), b = 1451.5(1), c = 1608.55(9) pm, β = 109.669(6)°, V = 4608.1(5)·10⁶ pm³, Z = 4, R₁ for 3874 symmetry independent reflections with I₀>2σ(I₀): 0.0438] contains Y^III coordinated by four Tf₂N‐ligands which all adopt a transoid‐conformation with respect to their –CF₃ groups. The oxygen coordination polyhedron around Y^III can be best described as a trigonal dodecahedron.One 1‐butyl‐3‐methylimidazolium cation compensates for the charge of the complex [Y(Tf₂N)₄]^? anion.     

Two dimeric CuII benzoate derivatives solvated with aceto­nitrile

The title compounds, tetrakis(μ‐benzoato‐O:O′)­bis(2,6‐di­amino­pyridine)‐1κN,2κN‐dicopper(II)–aceto­nitrile (1/2), [Cu₂(C₇H₅O₂)₄(C₅H₇N₃)₂]·2C₂H₃N, (I), and bis­(aceto­nitrile)‐1κN,2κN‐tetrakis(μ‐benzoato‐O:O′)­dicopper(II)–aceto­nitrile (1/1.5), [Cu₂(C₇H₅O₂)₄(C₂H₃N)₂]·1.5C₂H₃N, (II), crystallize as aceto­nitrile solvates exhibiting different stability. They have similar molecular structures with discrete dimeric units located at crystallographic inversion centres. The copper ions are bridged by four benzoate groups and neutral N‐donor ligands, viz. 2,6‐di­amino­pyridine in (I) and aceto­nitrile in (II), are coordinated at apical positions. The diverse stability is probably due to hydrogen‐bond interactions of the solvated aceto­nitrile mol­ecules with neighbouring dimers in compound (I).     

catena‐Poly[[[N,N′‐bis­(salicyl­idene)propane‐1,3‐diaminato]cobalt(III)]‐μ‐azido] and catena‐poly[[[N,N′‐bis(salicyl­idene)propane‐1,3‐diaminato]cobalt(III)]‐μ‐thio­cyanato]

The two title complexes, catena‐poly[[{2,2′‐[1,3‐propane­diylbis(nitrilo­methyl­idyne)]diphenolato}cobalt(III)]‐μ‐azido], [Co(C₁₇H₁₆N₂O₂)(N₃)]_n, (I), and catena‐poly[[{2,2′‐[1,3‐propane­diylbis(nitrilo­methyl­idyne)]diphenolato}cobalt(III)]‐μ‐thio­cyanato], [Co(C₁₇H₁₆N₂O₂)(NCS)]_n, (II), are isomorphous polynuclear cobalt(III) compounds. In both structures, the Co^III atom is six‐coordinated in an octa­hedral configuration by two N atoms and two O atoms of one Schiff base, and two terminal N or S atoms from two bridging ligands. The [N,N′‐bis­(salicyl­idene)propane‐1,3‐diaminato]cobalt(III) moieties are linked by the bridging ligands, viz. azide in (I) and thio­cyanate in (II), giving zigzag polymeric chains with backbones of the type [–Co—N—N—N—Co]_n in (I) or [–Co—N—C—S—Co]_n in (II) running along the c axis.     

Coordination environment of [UO2Br4] in ionic liquids and crystal structure of [Bmim]2[UO2Br4]

The complex formed by the reaction of the uranyl ion, UO₂²⁺, with bromide ions in the ionic liquids 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmim][Tf₂N]) and methyl-tributylammonium bis(trifluoromethylsulfonyl)imide ([MeBu₃N][Tf₂N]) has been investigated by UV–Vis and U L_III-edge EXAFS spectroscopy and compared to the crystal structure of [Bmim]₂[UO₂Br₄]. The solid state reveals a classical tetragonal bipyramid geometry for [UO₂Br₄]²⁻ with hydrogen bonds between the Bmim⁺ and the coordinated bromides. The UV–Vis spectroscopy reveals the quantitative formation of [UO₂Br₄]²⁻ when a stoichiometric amount of bromide ions is added to UO₂(CF₃SO₃)₂ in both Tf₂N-based ionic liquids. The absorption spectrum also suggests a D_4h symmetry for [UO₂Br₄]²⁻ in ionic liquids, as previously observed for the [UO₂Cl₄]²⁻ congener. EXAFS analysis supports this conclusion and demonstrates that the [UO₂Br₄]²⁻ coordination polyhedron is maintained in the ionic liquids without any coordinating solvent or water molecules. The mean U–O and U–Br distances in the solutions, determined by EXAFS, are, respectively, 1.766(2) and 2.821(2) Å in [Bmim][Tf₂N], and, respectively, 1.768(2) and 2.827(2) Å, in [MeBu₃N][Tf₂N]. Similar results are obtained in both ionic liquids indicating no significant influence of the ionic liquid cation either on the complexation reaction or on the structure of the uranyl species.     

catena‐Poly­[[bis­(quinoxaline‐κN)cobalt(II)]‐di‐μ‐dicyan­amido‐κ2N1:N5] and catena‐poly­[[bis(quinoxaline‐κN)copper(II)]‐di‐μ‐dicyan­amido‐κ2N1:N5]

Two new complexes, [Co(C₂N₃)₂(C₈H₆N₂)₂], (I), and [Cu(C₂N₃)₂(C₈H₆N₂)₂], (II), are reported. They are essentially isomorphous. Complex (I) displays distorted octahedral geometry, with the Co atom coordinated by four dicyan­amide nitrile N atoms [Co—N = 2.098 (3) and 2.104 (3) Å] in the basal plane, along with two monodentate quinoxaline N atoms [Co—N = 2.257 (2) Å] in the apical positions. In complex (II), the Cu atom is surrounded by four dicyan­amide nitrile N atoms [Cu—N = 2.003 (3) and 2.005 (3) Å] in the equatorial plane and two monodentate quinoxaline N atoms [Cu—N = 2.479 (3) Å] in the axial sites, to form a distorted tetragonal–bipyramidal geometry. The metal atoms reside on twofold axes of rotation. Neighbouring metal atoms are connected via double dicyan­amide bridges to form one‐dimensional infinite chains. Adjacent chains are then linked by π–π stacking interactions of the quinoxaline mol­ecules, resulting in the formation of a three‐dimensional structure.     

Thermophysical properties and thermodynamic phase behavior of ionic liquids

The thermal stability of many tested ionic liquids (ILs) was investigated by the TGA and DTA curves over the wide temperature range from 200 to 780 K. The TGA curves have mainly a sigmoid shape, which can be split into three segments. The thermal decomposition of the samples was higher than 500 K. For the ammonium salts, C₂BF₄, or C₂PF₆, or C₂N(CN)₂, or C₄Br, the temperatures of the decompositions were 583.5, 556.1, 545.1 and 525.3 K, respectively. Generally, it was found that the temperature of decomposition of investigated ionic liquid is strongly depended on the type of cation and the anion. Phase equilibria and thermophysical constants were measured also for the dialkoxy-imidazolium ILs, [(C₄H₉OCH₂)₂IM][BF₄], [(C₈H₁₇OCH₂)₂IM][Tf₂N], [(C₁₀H₂₁OCH₂)₂IM][Tf₂N] and for pyridinium IL, [Pyr][BF₄].The characterization and purity of the compounds were obtained by the elemental analysis, water content (Fisher method) and differential scanning microcalorimetry (DSC) analysis. From (DSC) method, the melting points, the enthalpies of fusion, the temperatures and enthalpies of solid-solid phase transitions and the half C_p temperatures of glass transition of all investigated ionic liquids were measured.The phase equilibria of these salts with common popular solvents: water, or alcohols or n-alkanes, or aromatic hydrocarbons have been measured by a dynamic method from 290 K to the melting point of IL, or to the boiling point of the solvent in the whole mole fraction range, x from 0 to 1.These salts mainly exhibit simple eutectic systems with immiscibility in the liquid phase with upper critical solution temperatures (UCST), not only with aromatic hydrocarbons, cycloalkanes and n-alkanes but also with longer chain alcohols. For example the C₂BF₄ salt show simple eutectic system with water and simple eutectic systems with immiscibility in the liquid phase with upper critical solution temperature with alcohols.The solid-liquid phase equilibria, SLE curves were correlated by means of the different G^Ex models utilizing parameters derived from the SLE. The root-mean-square deviations of the solubility temperatures for all calculated data depend on the particular system and the equation used.     

Microscopic Diffusion Dynamics of Silver Complex‐Based Room‐Temperature Ionic Liquids Probed by Quasielastic Neutron Scattering

Quasielastic neutron scattering is used to probe the microscopic diffusion dynamics of the hydrogen‐bearing cations of two different silver complex‐derived room‐temperature ionic liquids, [Ag(propylamine)₂⁺][Tf₂N^?] (Tf=trifluoromethanesulfonyl) and [Ag(1‐pentene)⁺][Tf₂N^?]. In the temperature range from 300 to 340 K, analysis of the scattering momentum transfer dependence of the data provides evidence for three distinct diffusion components. The slowest component describes the long‐range cationic translational diffusion. A possible link between the microscopic diffusion parameters and the structural features of the cations comprising these two ionic liquids is discussed.     

Clemizoledichlorocobalt(II)

The structure of di­chloro­[1‐(p‐chloro­benzyl)‐2‐(1‐pyrrol­idinyl­methyl‐N)‐1,3‐benz­imidazole‐N³]­cobalt(II), [Co­Cl₂(C₁₉­H₂₀ClN₃)], contains a mol­ecule of clemizole bound in a bidentate manner to cobalt through its imidazole and pyrrolidinyl N atoms, with significantly different Co—N distances of 1.976 (5) and 2.126 (5) Å, respectively. The geometry around cobalt is distorted tetrahedral, with significantly different Co—Cl distances of 2.217 (2) and 2.233 (2) Å, and the pyrrolidinyl ring is disordered.