Investigation of Large Polychloride Anions: [Cl11]−, [Cl12]2−, and [Cl13]−

For decades the chemistry of polyhalides was dominated by polyiodides and more recently also by an increasing number of polybromides. However, apart from a few structures containing trichloride anions and a single report on an octachloride dianion, [Cl₈]^2?, polychlorine compounds such as polychloride anions are unknown. Herein, we report on the synthesis and investigation of large polychloride monoanions such as [Cl₁₁]^? found in [AsPh₄][Cl₁₁], [PPh₄][Cl₁₁], and [PNP][Cl₁₁]?Cl₂, and [Cl₁₃]^? obtained in [PNP][Cl₁₃]. The polychloride dianion [Cl₁₂]^2? has been obtained in [NMe₃Ph]₂[Cl₁₂]. The novel compounds have been thoroughly characterized by NMR spectroscopy, single‐crystal Raman spectroscopy, and single‐crystal X‐ray diffraction. The assignment of their spectra is supported by molecular and periodic solid‐state quantum‐chemical calculations.     

Ionic Association of the Ionic Liquids [C4mim][BF4], [C4mim][PF6], and [Cnmim]Br in Molecular Solvents

Considering the ionic nature of ionic liquids (ILs), ionic association is expected to be essential in solutions of ILs and to have an important influence on their applications. Although numerous studies have been reported for the ionic association behavior of ILs in solution, quantitative results are quite scarce. Herein, the conductivities of the ILs [C_nmim]Br (n=4, 6, 8, 10, 12), [C₄mim][BF₄], and [C₄mim][PF₆] in various molecular solvents (water, methanol, 1‐propanol, 1‐pentanol, acetonitrile, and acetone) are determined at 298.15 K as a function of IL concentration. The conductance data are analyzed by the Lee–Wheaton conductivity equation in terms of the ionic association constant (K_A) and the limiting molar conductance (Λ_m⁰). Combined with the values for the Br^? anion reported in the literature, the limiting molar conductivities and the transference numbers of the cations and [BF₄]^? and [PF₆]^? anions are calculated in the molecular solvents. It is shown that the alkyl chain length of the cations and type of anion affect the ionic association constants and limiting molar conductivities of the ILs. For a given anion (Br^?), the Λ_m⁰ values decrease with increasing alkyl chain length of the cations in all the molecular solvents, whereas the K_A values of the ILs decrease in organic solvents but increase in water as the alkyl chain length of the cations increases. For the [C₄mim]⁺ cation, the limiting molar conductivities of the ILs decrease in the order Br^?>[BF₄]^?>[PF₆]^?, and their ionic association constants follow the order [BF₄]^?>[PF₆]^?>Br^? in water, acetone, and acetonitrile. Furthermore, and similar to the classical electrolytes, a linear relationship is observed between ln K_A of the ILs and the reciprocal of the dielectric constants of the molecular solvents. The ILs are solvated to a different extent by the molecular solvents, and ionic association is affected significantly by ionic solvation. This information is expected to be useful for the modulation of the IL conductance by the alkyl chain length of the cations, type of anion, and physical properties of the molecular solvents.     

Synthesis and Characterization of 5‐Cyanotetrazolide‐Based Ionic Liquids

New salts based on imidazolium, pyrrolidinium, phosphonium, guanidinium, and ammonium cations together with the 5‐cyanotetrazolide anion [C₂N₅]^? are reported. Depending on the nature of cation–anion interactions, characterized by XRD, the ionic liquids (ILs) have a low viscosity and are liquid at room temperature or have higher melting temperatures. Thermogravimetric analysis, cyclic voltammetry, viscosimetry, and impedance spectroscopy display a thermal stability up to 230 °C, an electrochemical window of 4.5 V, a viscosity of 25 mPa s at 20 °C, and an ionic conductivity of 5.4 mS cm^?1 at 20 °C for the IL 1‐butyl‐1‐methylpyrrolidinium 5‐cyanotetrazolide [BMPyr][C₂N₅]. On the basis of these results, the synthesized compounds are promising electrolytes for lithium‐ion batteries.     

Phosphorus(III) Cations Supported by a PNP Pincer Ligand and Sub‐Stoichiometric Generation of P4 from Thermolysis of a Nickel Insertion Product

Neutral, mono‐, and dicationic phosphorus(III) compounds are accessible with a supporting PNP pincer ligand (PNP=[4‐Me‐2‐iPr₂P‐C₆H₃)₂N]). Reaction of (PNP)H with PCl₃ and nBu₃N furnished (PNP)PCl₂ ( 1 ), which displays a highly temperature‐dependent structure in solution. Synthesis and characterization by NMR spectroscopy and X‐ray crystallography of Cl/Br‐scrambled derivatives, a monocationic derivative [(PNP)PCl][HCB₁₁H₁₁] ( 4 ), and the dicationic derivatives [(PNP)P][OTf]₂ ( 5 ), [(PNP)P][B(C₆F₅)₄]₂ ( 6 ), [(PNP)P][B₁₂Cl₁₂] ( 7 ) established that 1 not only undergoes several fluxional processes in solution but also possesses a temperature‐dependent ground state structure. Reaction of 1 with a Ni⁰ source initially leads to a phosphine–phosphinidene complex, followed by thermal generation of P₄.     

DFT Study of the Geometrical and Electronic Structures of Geminal Dicationic Ionic Liquids 1,3‐Bis[3‐methylimidazolium‐1‐yl]hexane Halides

In this work, the geometrical and electronic properties of the mono cationic ionic liquid 1‐hexyl‐3‐methylimidazolium halides ([C₆(mim)]⁺_X^?, X=Cl, Br and I) and dicationic ionic liquid 1,3‐bis[3‐methylimidazolium‐1‐yl]hexane halides ([C₆(mim)₂X₂], X=Cl, Br and I) were studied using the density functional theory (DFT). The most stable conformer of these two types ionic liquids (IL) are determined and compared with each other. Results show that in the most stable conformers, in both monocationic ILs and dicationic ILs, the Cl^? and Br^? anions prefer to locate almost in the plane of the imidazolium ring whereas the I^? anion prefers nearly vertical location respect to the imidazolium ring plan. Comparison of hydrogen bonding and ionic interactions in these two types of ionic liquids reveals that these ionic liquids can be formed hydrogen bond by Cl^? and Br^? anion. The calculated thermodynamic functions show that the interaction of cation — anion pair in the dicationic ionic liquids are more than monocationic ionic liquids and these interactions decrease with increasing the halide anion atomic weight.     

Non‐Ideal Mixing Behaviour of Hydrogen Bonding in Mixtures of Protic Ionic Liquids

Ionic liquids (ILs) attract interest in science and technology as a result of their unique properties. Binary and ternary mixtures of ILs significantly increase the number of possible cation/anion combinations, resulting in targeted physical and chemical properties. In this work, we study the mixing behaviour of two protic ILs: triethyl ammonium methylsulfonate [Et₃NH][CH₃SO₃] and triethylammonium triflate [Et₃NH][CF₃SO₃]. We find a characteristic deviation from ideal mixing by means of low‐frequency infrared spectroscopy. By using molecular dynamics simulations, we explain this behaviour as being the result of different strengths of anion/cation hydrogen bonding. This non‐ideality of non‐random H‐bond mixing is also reflected in macroscopic properties such as the viscosity. Mixing suitable ILs may, thus, result in new ILs with targeted physical properties.     

Halogencyane als Liganden Darstellung und Kristallstruktur des [Fe(NCBr)6](FeBr4)2 · 2 BrCN

Halogencyanogens as Ligands. Preparation and Crystal Structure of [Fe(NCBr)₆](FeBr₄)₂ · 2 BrCN Hexa(bromocyanogen)iron(II) bistetrabromoferrate(III) bromocyanogen(1/2) may be prepared by reaction of FeBr₂ and BrCN. It crystallizes triclinically in the space group P1 with a = 1249.3, b = 823.5, c = 962.2 pm, α = 89.58°, β = 77.72°, γ = 87.79° and Z = 1 formula unit. The salt-like compound is built up by nearly octahedral, only bromocyanogen molecules as ligands containing cations [Fe(NCBr)₆]²⁺, nearly tetrahedral anions [FeBr₄]^? and additional BrCN molecules. The packing of the ions may be compared with the CdCl₂ type. Short Br ?Br contacts between the coordinated BrCN molecules and Br^? ions connect the building units to a ribbon along [111 ] which contains the solvating BrCN molecules, too.     

Elucidating Interactions between DMSO and Chelate‐Based Ionic Liquids

The C?D bond stretching vibrations of deuterated dimethyl sulfoxide ([D₆]DMSO) and the C₂?H bond stretching vibrations of 1,1,1,5,5,5‐hexafluoropentane‐2,4‐dione (hfac) ligand in anion are chosen as probes to elucidate the solvent–solute interaction between chelate‐based ionic liquids (ILs) and DMSO by vibrational spectroscopic studies. The indirect effect from the interaction of the adjacent S=O functional group of DMSO with the cation [C₁₀mim]⁺ and anion [Mn(hfac)₃]^? of the ILs leads to the blue‐shift of the C?D stretching vibrations of DMSO. The C₂?H bond stretching vibrations in hfac ligand is closely related to the ionic hydrogen bond strength between the cation and anion of chelate‐based ILs. EPR studies reveal that the crystal field of the central metal is kept when the chelate‐based ILs are in different microstructure environment in the solution.     

Size Matters! On the Way to Ionic Liquid Systems without Ion Pairing

Several, partly new, ionic liquids (ILs) containing imidazolium and ammonium cations as well as the medium‐sized [NTf₂]^? (0.230 nm³; Tf=CF₃SO₃^?) and the large [Al(hfip)₄]^? (0.581 nm³; hfip=OC(H)(CF₃)₂) anions were synthesized and characterized. Their temperature‐dependent viscosities and conductivities between 25 and 80 °C showed typical Vogel–Fulcher–Tammann (VFT) behavior. Ion‐specific self‐diffusion constants were measured at room temperature by pulsed‐gradient stimulated‐echo (PGSTE) NMR experiments. In general, self‐diffusion constants of both cations and anions in [Al(hfip)₄]^?‐based ILs were higher than in [NTf₂]^?‐based ILs. Ionicities were calculated from self‐diffusion constants and measured bulk conductivities, and showed that [Al(hfip)₄]^?‐based ILs yield higher ionicities than their [NTf₂]^? analogues, the former of which reach values of virtually 100 % in some cases.From these observations it was concluded that [Al(hfip)₄]^?‐based ILs come close to systems without any interactions, and this hypothesis is underlined with a Hirshfeld analysis. Additionally, a robust, modified Marcus theory quantitatively accounted for the differences between the two anions and yielded a minimum of the activation energy for ion movement at an anion diameter of slightly greater than 1 nm, which fits almost perfectly the size of [Al(hfip)₄]^?. Shallow Coulomb potential wells are responsible for the high mobility of ILs with such anions.     

Structural Diversity in Thallium Chemistry. Part V

From thallium(III) bromide solution, the unsubstituted pyridinium cation yields a complex ( 1 ) with the [Tl₂Br₉]^3? anionic stoichiometry. The Raman spectrum and single‐crystal X‐ray crystallographic analysis showed that the salt contains independent [TlBr₄]^? and bromide anions. A variety of mono‐ and disubstituted pyridinium cations were also employed in similar syntheses. The 2‐bromopyridinium cation gave a salt 2 with [TlBr₅]^2? stoichiometry, but the crystal structure revealed very weakly interacting [TlBr₄]^? and bromide anions with a Tl ???Br^? distance of 4.1545(6) Å. The 2‐(ammoniomethyl)pyridinium and 2‐amino‐4‐methylpyridinium cations yielded complexes containing [TlBr₅]^2? ( 3 ) and [TlBr₄]^? ( 4 ) species, respectively, which were confirmed by Raman spectroscopy and X‐ray crystallographic analyses. For 3 , the [TlBr₅]^2? anion has a highly distorted trigonal bipyramidal conformation with one long axial Tl ???Br bond of 3.400(2) Å. Microanalytical results in conjunction with Raman spectra from a further five salts confirmed that they all contain the simple [TlBr₄]^? anion. N? H ???Br Hydrogen bonds clearly influence the nature of the anionic species obtained in these systems.     

Polychloride Monoanions from [Cl3]− to [Cl9]−: A Raman Spectroscopic and Quantum Chemical Investigation

Polychloride monoanions stabilized by quaternary ammonium salts are investigated using Raman spectroscopy and state‐of‐the‐art quantum‐chemical calculations. A regular V‐shaped pentachloride is characterized for the [N(Me)₄][Cl₅] salt, whereas a hockey‐stick‐like structure is tentatively assigned for [N(Et)₄][Cl₂???Cl₃^?]. Increasing the size of the cation to the quaternary ammonium salts [NPr₄]⁺ and [NBu₄]⁺ leads to the formation of the [Cl₃]^? anion. The latter is found to be a pale yellow liquid at about 40 °C, whereas all the other compounds exist as powders. Further to these observations, the novel [Cl₉]^? anion is characterized by low‐temperature Raman spectroscopy in conjunction with quantum‐chemical calculations.     

Polarity Behaviour and Specific Interactions of Imidazolium‐Based Ionic Liquids in Ethylene Glycol

The molecular interactions of the ionic liquids (ILs) 1‐butyl‐3‐methylimidazolium tetrafluoroborate [C₄mim][BF₄], 3‐methyl‐1‐octylimidazolium tetrafluoroborate [C₈mim][BF₄] and 1‐butyl‐3‐methylimidazolium octylsulfate [C₄mim][C₈OSO₃] are investigated in ethylene glycol (EG) over the whole mole fraction range using fluorescence (steady‐state and time‐resolved), Fourier transform infrared and nuclear magnetic resonance (NMR) spectroscopy. The cybotactic region surrounding the pyrene fluorescent probe exhibits peculiar characteristics for different ILs in the EG‐rich region. The extent of solute–solvent interactions is assessed by determining the deviations of experimentally observed vibronic band intensity ratios of peak 1 to peak 3 of pyrene fluorescence (I₁/I₃) from a composite I₁/I₃ value obtained using a preferential solvation model. A distinct vibrational frequency shift for various stretching modes of EG (O? H) or ILs (C? H of ring protons, B? F and S?O of anions) indicates specific interactional preferences of EG toward the IL protons/anion. Splitting of the O? H vibration band of EG at 3000–3700 cm^?1 into three separate bands, and analysis of the changes in location and area of these bands as a function of concentration enable precise determination of the effect of ILs on hydrogen bridges of EG. NMR chemical shifts and their deviations from ideality show multiple hydrogen‐bonding interactions of varying strengths between unlike molecules in the mixtures. A comparison of spectroscopic results with thermodynamic properties shows that the mixing microscopic behaviour of the investigated systems is completely different from the macroscopic behaviour, which is primarily governed by the difference in shape, size and nature of the molecules.     

Influences of steric bulkiness in hydrotris(pyrazolyl)borate ligands on ethylene polymerization reaction

Manganese(II) complex catalysts with hydrotris(pyrazolyl)borate ligands have been examined on their catalytic performance in ethylene polymerization and ethylene/1‐hexene copolymerization. The activities of [Mn(L6)(Cl)(NCMe)] ( 1 ) and [Mn(L10)(Cl)] ( 2 ) activated by Al(i‐Bu)₃/[Ph₃C][B(C₆F₅)₄] for ethylene polymerization go up to 326 and 11 kg mol (cat^?1) h^?1, respectively, (L6^? = hydrotris(3‐phenyl‐5‐methyl‐1‐pyrazolyl)borate anion, L10^? = hydrotris(3‐adamantyl‐5‐isopropyl‐1‐pyrazolyl)borate anion). In particular, for ethylene/1‐hexene copolymerization, complex 1 gives high‐molecular‐weight poly(ethylene‐co‐1‐hexene)s with the highest M_w of 439,000 in manganese olefin polymerization catalyst systems. Moreover, the 1‐hexene incorporation by complex 1 seems more efficient than that by [Mn(L3)(Cl)] ( 4 ) (L3^? = hydrotris(3‐tertiary butyl‐5‐isopropyl‐1‐pyrazolyl)borate anion). In this work, we demonstrated that the coordination geometry and coordination number are also important factors for ethylene polymerization reaction as well as steric hindrances and ligand frameworks in our manganese(II) catalysts. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5720–5727, 2009     

Synthesis of Pyrazolo[3,4‐d]pyrimidin‐4‐ones Catalyzed by Br?nsted‐acidic Ionic Liquids as Highly Efficient and Reusable Catalysts

A convenient and efficient method for the synthesis of pyrazolo[3,4‐d]pyrimidin‐4‐ones via heterocyclization reaction of 5‐amino‐1H‐pyrazole‐4‐carboxamides with triethyl orthoesters using two Br?nsted‐acidic ionic liquids, 3‐methyl‐1‐(4‐sulfonic acid)butylimidazolium hydrogen sulfate [MIM⁺(CH₂)₄SO₃H][HSO₄^?] or N‐(4‐sulfonic acid)butyl triethylammonium hydrogen sulfate [Et₃N⁺(CH₂)₄SO₃H][HSO₄^?], as efficient homogeneous catalysts under solvent‐free conditions is described.     

Preparation and Structural Characterization of [CpRu(1,10-phenanthroline)(CH3CN)][X] and Precursor Complexes (X=PF6, BArF,TRISPHAT-N)

Cationic [Ru(η⁵-C₅H₅)(CH₃CN)₃]⁺ complex, tris(acetonitrile)(cyclopentadienyl)ruthenium(II), gives rise to a very rich organometallic chemistry. Combined with diimine ligands, and 1,10-phenanthroline in particular, this system efficiently catalyzes diazo decomposition processes to generate metal-carbenes which undergo a series of original transformations in the presence of Lewis basic substrates. Herein, syntheses and characterizations of [CpRu(Phen)(L)] complexes with (large) lipophilic non-coordinating (PF₆⁻ and BAr_F⁻) and coordinating TRISPHAT-N⁻ anions are reported. Complex [CpRu(η⁶-naphthalene)][BAr_F] ( [1][BAr_F] ) is readily accessible, in high yield, by direct counterion exchange between [1][PF₆] and sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBAr_F) salts. Ligand exchange of [1][BAr_F] in acetonitrile generated stable [Ru(η⁵-C₅H₅)(CH₃CN)₃][BAr_F] ( [2][BAr_F] ) complex in high yield. Then, the desired [CpRu(Phen)(CH₃CN)] ( [3] ) complexes were obtained from either the [1] or [2] complex in the presence of the 1,10-phenanthroline as ligand. For characterization and comparison purposes, the anionic hemilabile ligand TRISPHAT−N (TTN) was introduced on the ruthenium center, from the complex [3][PF₆] , to quantitatively generate the desired complex [CpRu(Phen)(TTN)] ( [4] ) by displacement of the remaining acetonitrile ligand and of the PF₆⁻ anion. Solid state structures of complexes [1][BAr_F] , [2][BAr_F] , [3][BAr_F] , [3][PF₆] and [4] were determined by X-ray diffraction studies and are discussed herein.     

Extraction of Palladium(II) and Platinum(IV) from Hydrochloric Acid Solutions with Trioctylammonium Nitrate Ionic Liquid without Dilution

The fundamental properties and extraction capability of an ionic liquid (IL), trioctylammonium nitrate ([HTOA][NO₃]), for Pd^II and Pt^IV, are investigated. At room temperature, [HTOA][NO₃] is a solid (melting point: 30.7 °C), but it becomes a liquid (melting point: 16.7 °C) when saturated with water. Water-saturated [HTOA][NO₃] exhibits a viscosity of 267.1 mPa·s and an aqueous solubility of 2.821?×?10^?4 mol·dm^?3 at 25 °C, and can be used as an extraction solvent without dilution. [HTOA][NO₃] exhibits an extremely high extraction capability for Pd^II and Pt^IV in dilute hydrochloric acid (0.1–2 mol·dm^?3 HCl); the distribution ratio reaches 3 × 10⁴ for both the metals. From electrospray ionization mass spectrometry analysis, the species extracted in the IL phase are [PdCl₃]^? and [PdCl₂(NO₃)]^? for Pd^II and [PtCl₆]^2? and [PtCl₅]^? for Pt^IV. A majority of the other transition metals are considerably less or marginally extracted into [HTOA][NO₃] from a 0.1 mol·dm^?3 hydrochloric acid solution. The extraction capacity of [HTOA][NO₃] is greater than that of other hydrophobic ILs such as [HTOA]Cl and bis(trifluoromethanesulfonyl)imide-based ILs. The metals extracted into the IL phase are quantitatively back-extracted using an aqueous solution containing thiourea and nitric acid. By controlling the thiourea concentration and shaking time, Pd^II and Pt^IV are mutually separated to some extent in the back extraction process. The IL phase used for the back extraction can be reused for the forward extraction of these metals after scrubbing it with an aqueous nitric acid solution.     

The physicochemical properties of some imidazolium-based ionic liquids and their binary mixtures

The density, viscosity and conductivity of ionic liquids (ILs), 1-octyl-3-methylimidazolium tetrafluoroborate ([omim][BF4]), 1-octyl-3-methylimidazolium chloride ([omim][Cl]), 1-hexyl-3-methylimidazolium tetrafluoroborate ([hmim] BF4]), 1-hexyl- 3-methylimidazolium chloride ([hmim][Cl]), 1-hexyl-3-methylimidazolium hexafluorophosphate ([hmim][PF6]), and the [omim][BF4] + [omim][Cl], [hmim][BF4] + [hmim][Cl], and [hmim][PF6] + [hmim][Cl] binary mixtures were studied at dif- ferent temperatures. It was demonstrated that the densities of both the neat ILs and their mixtures varied linearly with temper- ature. The density sensitivity of a binary mixture is between those of the two components. The excess molar volumes (VE) of [hmim][BF4] + [hmim][Cl] and [hmim][PF6] + [hmim][Cl] mixtures are positive in the whole composition range. For [omim][BF4] + [omim][Cl], the VE is also positive in the [omim][Cl]-rich region, but is negative in the [omim][BF4]-rich re- gion. The viscosity or conductivity of a mixture is in the intermediate of those of the two neat ILs. For all the neat ILs and the binary mixtures studied, the order of conductivity is opposite to that of the viscosity. The Vogel-Tammann-Fulcher (VTF) equations can be used to fit the viscosity and conductivity of all the neat ILs and the binary mixtures. The neat ILs and their mixtures obey the Fractional Walden Rule very well, and the values of the Walden slopes are all smaller than unit, indicating obvious ion associations in the neat ILs and the binary mixtures.     

Studies on the Reactivity of [Ge9]4− towards [Fe(cot)(CO)3]: Synthesis and Characterization of [Ge8Fe(CO)3]3− and of the Anionic Organometallic Species [Fe(cot)(CO)3]−

Reaction of cyclooctatetraene (COT) iron(II) tricarbonyl, [Fe(cot)(CO)₃], with one equivalent of K₄Ge₉ in ethylenediamine (en) yielded the cluster anion [Ge₈Fe(CO)₃]^3? which was crystallographically‐characterized as a [K(2,2,2‐crypt)]⁺ salt in [K(2,2,2‐crypt)]₃[Ge₈Fe(CO)₃]. The chemically‐reduced organometallic species [Fe(η³‐C₈H₈)(CO)₃]^? was also isolated as a side‐product from this reaction as [K(2,2,2‐crypt)][Fe(η³‐C₈H₈)(CO)₃]. Both species were further characterized by EPR and IR spectroscopy and electrospray mass spectrometry. The [Ge₈Fe(CO)₃]^3? cluster anion represents an unprecedented functionalized germanium Zintl anion in which the nine‐atom precursor cluster has lost a vertex, which has been replaced by a transition‐metal moiety.     

Ionic thermo‐responsive copolymer with multi LCST values: easy and fast LCST‐change through anion exchange

An ionic thermo‐responsive copolymer with multiple lower critical solution temperatures (multi‐LCSTs) has been developed, and the multi‐LCSTs were easily changeable according to the various counter anion types. The multi‐LCST values were achieved by introducing an ionic segment with an imidazolium moiety within the p‐NIPAAm polymer chain to produce poly(NIPAAm‐co‐BVIm) copolymers, [p‐NIBIm]⁺[Br]^?, and changing the counter anion type to produce [p‐NIBIm]⁺[X]^? (X = Cl, AcO, HCO₃, BF₄, CF₃SO₃, PF₆, SbF₆). The as‐prepared temperature‐responsive copolymers were physicochemically characterized via proton nuclear magnetic resonance spectroscopy (¹H‐NMR), Fourier‐transform infrared, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. Their various LCST values, micelle sizes, and surface charges were determined using an Ultraviolet‐visible spectrophotometer and a Zeta (ξ) sizer, which were fitted with temperature and stirring control. The copolymers showed a broad LCST spectrum between 39°C and 52°C. The Zeta (ξ) potential values at a pH = 7 decreased from about +9.7 for [p‐NIBIm]⁺[X]^? (X = Cl ≈ Br) to about +2.0 mV for [p‐NIBIm]⁺[X]^? (X = PF₆ ≈ SbF₆). The micelle size (or volume) of the copolymers with different anionic species gradually increased from 181.2 nm (or 2.49 × 10^?17 cm^?3) for [p‐NIBIm]⁺[Br]^? to 229.2 nm (or 5.04 × 10^?17 cm^?3) for [p‐NIBIm]⁺[CF₃SO₃]^?, showing a clear effect of the anion on the micelle size (or volume) at a constant temperature, such as body temperature. The fact that the most important physicochemical properties for the thermo‐responsive copolymers, such as the LCST value, micelle size (or volume), and surface charge, could be easily controlled only through the anion exchange suggests these are highly applicable as ionic thermo‐responsive copolymers in a drug (or gene, protein) delivery system. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of Dimethyl Carbonate on the Dynamic Properties and Ionicities of Ionic Liquids with [MIII(hfip)4]− (M=B,Al) Anions

Several ionic liquids (ILs) comprising [B(hfip)₄]^? [hfip=OCH(CF₃)₂] or [Al(hfip)₄]^? anions and imidazolium or ammonium cations were prepared and mixed with up to 270 mol % of dimethyl carbonate (DMC). The viscosities, conductivities, and self‐diffusion constants of these mixtures and, where possible, of the neat ILs were measured and compared with common [NTf₂]^? based ILs and their mixtures with DMC. A tremendous decrease of the viscosities and a likewise increase of the conductivities and diffusion constants can be achieved for all classes of ILs. However, the order of the conductivities is partially reversed in the diffusion data. This is probably due to the low dielectric constant of DMC and the, thus, favored ion pairing, as evidenced, for example, by the calculated ionicities. Altogether, our data show that the chemically robust, but high‐melting and more viscous [B(hfip)₄]^? ILs might be candidates for electrolytes when mixed with suitable molecular solvents.