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Six ionic liquids based on the 1-butyl-3-methylimidazolium cation have been studied. As anions Cl-, Br-, I-, [NCS]-, [N(CN)2]-, and [BF4]- were selected. The electrical conductivities were determined between 173 and 393 K based on impedance measurements in the frequency range from 0.1 to 107 Hz. The electrical conductivity increases, whereas the glass transition temperature, the fragility, and the low temperature activation energy decrease with increasing anion size. The results can be understood from the changing anion-cation interaction strength with changing anion size and from the energy landscape interpretation of the glass transition dynamics. [ABSTRACT FROM AUTHOR]

PX3 compounds (X=Cl, Br, I) in imidazolium halide ionic liquids combine with the anion Z (Z=Cl, Br, I) of the solvent to form [PX3Z]− complex anions. These anions have a sawhorse shape in which the lone pair of the phosphorus atom fills the third equatorial position of the pseudotrigonal bipyramid. Theoretical results show that this association remains incomplete due to strong hydrogen bonding with the cations of the ionic liquid, which competes with the phosphorus trihalide for interaction with the Z− anion. Temperature‐dependent 31P NMR experiments indicated that the P−Z binding is weaker at higher temperature. Both theory and experiment evidence dynamic exchange of the halide anions at the phosphorus atom, together with continuous switching of the ligands at the phosphorus atom between equatorial and axial positions. Detailed knowledge of the mechanism of the spontaneous exchange of halogen atoms at phosphorus trihalides suggests a way to design novel, highly conducting ionic‐liquid mixtures. Dynamic halide exchange: Phosphorus trihalides PX3 form [PX4]− anions in 1,3‐dialkyl imidazolium halide ionic liquids (HMIM in scheme). The dynamic exchange of the anions at the phosphorus atom shows typical characteristics of a Grotthuss‐like diffusion mechanism and potentially offers a way to design highly conducting materials. [ABSTRACT FROM AUTHOR]

The seven-member alicyclic secondary amine, azepane, has been used as starting material to synthesise a new family of room temperature ionic liquids. Such useful transformations of this coproduct of diamine production processes, generated in large amounts in the polyamide industry, would mitigate its disposal, which usually involves combustion. Reaction of azepane with 1-bromoalkanes or 1-bromoalkoxyalkanes produced the corresponding tertiary amines with good selectivity; further quaternisation reactions with the appropriate methylating agents yielded quaternary azepanium salts, [Rmazp]X (R = alkyl or alkoxyalkyl; X− = I−, [CF3CO2]− or [OTf]−; Tf = (trifluoromethyl)sulfonyl). Analogous [NTf2]− salts have also been produced by metathetic reactions. Liquid temperature ranges are significantly affected by the nature of the anion and the substituents on the azepanium cation core; for example, [CF3CO2]− or [OTf]− salts based on cations with alkyl substitution are solids, whereas those with alkoxyalkyl substitution are liquids at ambient temperature. The crystal structures of [C4mazp][CF3CO2], [C4mazp]I and [C6mazp][NTf2] (C4 = butyl, C6 = hexyl) are reported. The effects of the structural features of cations and anions on density, viscosity and conductivity data are discussed. The presence of ether linkages in the cationic side chains causes a marked decrease in viscosities and an increase in conductivities. Cyclic voltammetry showed that azepanium ionic liquids exhibit extremely wide electrochemical windows, thus becoming promising and safe alternatives to electrolytes based on volatile organic compounds. [ABSTRACT FROM AUTHOR]

lmidazolium, pyridinium, pyrrolidinium, piperidinium, morpholinium, and quaternary ammonium bis(trifluoromethyl- sulfonyl)imide salts were functionalized with a carboxyl group. These ionic liquids are useful for the selective dissolution of metal oxides and hydroxides. Although these hydrophobic ionic liquids are immiscible with water at room temperature, several of them form a single phase with water at elevated temperatures. Phase separation occurs upon cooling. This thermomorphic behavior has been investigated by [sup1]H NMR, and it was found that it can be attributed to the temperature-dependent hydration and hydrogen-bond formation of the ionic liquid components. The crystal structures of four ionic liquids and five metal complexes have been determined. [ABSTRACT FROM AUTHOR]

Ionic liquids containing the hexafluoroacetylacetonate anion are immiscible with water and they exhibit strong metal-complexing ability. [ABSTRACT FROM AUTHOR]

Phosphorus halides in 1‐alkyl‐3‐methylimidazolium halide ionic liquids form complex anions. The dynamic exchange of the halides in these complexes—observed by theoretical calculations—suggests the possibility of a structural diffusion of the halide anions in the liquid. Accordingly, potential highly conducting solvents are envisioned, in which substitution reactions at molecular halides in halide ionic liquids can be exploited to increase ion mobilities. More information can be found in the Full Paper by O. Hollóczki, et al. on page 16323. [ABSTRACT FROM AUTHOR]

The article reports on the synthesis of the first ionic liquids containing lanthanide that were based on the 1-butyl-3-methylimidazolium cation and lanthanide thiocyanate anions. A metathesis procedure starting from stoichiometric amounts of lanthanide(III) perchlorate, ammonium thiocyanate, and a thiocyanate ionic liquid was used to synthesize the compounds. It claims that most of these liquids are supercooled at room temperature and likewise tend to form glasses upon cooling.

The title compound, [AuIII(C9H10NO2)2][AuIIICl4], contains [AuIII(C9H10NO2)2]+ cations and [AuIIICl4]− anions with each of the gold(III) ions in a typical four-coordinate square-planar geometry. Both gold(III) metal centers are located on inversion centers. [ABSTRACT FROM AUTHOR]

The anionic speciation of chlorostannate (II) ionic liquids, prepared by mixing 1-alkyl-3-methylimidazolium chloride and tin (II) chloride in various molar ratios, XsnCl2, was investigated in both solid and liquid states. The room temperature ionic liquids were investigated by 119Sn NMR spectroscopy, X-ray photoelectron spectroscopy, and viscom-etry. Crystalline samples were studied using Raman spectroscopy, single-crystal X-ray crystallography, and differential scanning calorimetry. Both liquid and solid systems (crystal-lized from the melt) contained [SnCl3]- in equilibrium widi Cl- when XSnCl2 < 0.50, [SnCl3]- in equilibrium with [Sn2Cl5]- when XsnCl2 > 0.50, and only [SnCl3]- when XSnCl2 = 0.50. Tin(II) chloride was found to precipitate when XSncl2 < 0.63. No evidence was detected for the existence of [SnCl4]2- across the entire range of XsnCl2, although such anions have been reported in the literature for chlorostannate (II) organic salts crystallized from organic solvents. Furthermore, the Lewis acidity of the chlorostannate(II)-based systems, expressed by their Gutmann acceptor number, has been determined as a function of the composition, Xsncl2 to reveal Lewis acidity for XSnCl2 > 0.50 samples comparable to the analogous systems based on zinc (II). A change of the Lewis basicity of die anion was estimated using ¹H NMR spectroscopy, by comparison of the measured chemical shifts of the C-2 hydrogen in the imidazolium ring. Finally, compositions containing free chloride anions (XSnCl2 < 0.50) were found to oxidize slowly in air to form a chlorostannate (IV) ionic liquid containing the [SnCl6]2- anion. [ABSTRACT FROM AUTHOR]

The halide derivatives of yttrium ortho-oxomolybdate YX[MoO4] (X = F, Cl) both crystallize in the monoclinic system with four formula units per unit cell. YF[MoO4] exhibits a primitive cell setting (space group P21/c; a = 519,62(2) pm, b = 1225.14(7) pm, c = 663.30(3) pm, β = 112.851(4)°), whereas the lattice of YCl[MoO4] shows face-centering (space group C2/m; a 1019.0?(5) pm, b = 720.67(4) pm, c = 681 .50(3) pm, β = 107.130(4)°). The two compounds each contain crystallographically unique Y3+ cations, which are found to have a coordination environment of six oxide and two halide anions. In the case of YF[MoO4], the coordination environment is seen as square antiprisms, and for YCl[MoO4], trigon-dodecahedra are found. The discrete tetrahedral [MoO4]2- units of the fluoride derivative are exclusively bound by six terminal Y3+ cations, while those of the chloride compound show a 5-fold coordination around the tetrahedra with one edge-bridging and four terminal Y3+ cations. The halide anions in each compound exhibit a coordination number of two, building up isolated planar rhombus-shaped units according to [Y2F2]4+ in YF[MoO4] and [Y2Cl2]4+ in YCl[MoO4], respectively. Both compounds were synthesized at high temperatures using Y2O3, MoO3, and the corresponding yttrium trihalide in a molar ratio of 1:3:1. Single crystals of both are insensitive to moist air and are found to be coarse shaped and colorless with optical band gaps situated in the near UV around 3.78 eV for the fluoride and 3.82 eV for the chloride derivative. Furthermore, YF[MoO4] seems to be a suitable material for doping to obtain luminescent materials because the Eu3+-doped compound shows an intense red luminescence, which has been spectroscopically investigated. [ABSTRACT FROM AUTHOR]