A new series of low-melting ammonium salts based on the [nido-7,8-C2B9H12]– anion have been synthesized and characterized, and their physicochemical properties including spectroscopic properties, thermal properties, surface properties, solubility, density, viscosity, electrochemical properties, and tribological properties have been studied in detail. In comparison with previously reported carborane-derivatized imidazolium or pyridinium salts, these diether-functionalized ammonium salts display lower phase transition temperatures (Tg = –76 to –57 °C), and four exist as liquids at room temperature due to their flexible alkoxy chains. TGA analysis revealed that the weight loss rates of these carborane-derivatized low-melting salts were ca. 30–80 wt.-% after thermal decomposition, which is different from the traditional RTILs. SEM images showed that the resulting residue had hollow reticular shell morphology, and XPS and XRD analyses indicate that the main components of the skeleton are B2O3 and amorphous carbon. This provides a new strategy for preparing new inorganic porous materials by thermal decomposition of these low-melting salts.

Keywords: Ionic liquids / Carboranes / Boron / Carbon / Raman spectroscopy / IR spectrocsopy

★★★☆☆ Liu SM,Chen ZJ,Zhang QH,et al. Carborane-derivatized Low-melting Salts With Ether-functionalized Cations—preparation And Properties[J]. Eur. J. Inorg. Chem.,2011:1910–1920.

The direct production of methyl, ethyl and n-butyl carbamates (MC, EC and BC) from NH3, CO2 and alcohols could efficiently be catalyzed by V2O5, and ca. 11–25% yields with 98% selectivity for alkyl carbamates could be obtained. The catalyst could be recycled six times without obvious decrease in catalytic activity. XRD and XPS analysis showed that in-situ produced (NH4)2V3O8 was the catalytically active species.

Keywords: Carbon dioxide; Vanadium(V)-oxide catalyst; Fixation; Alkyl carbamates

★★★☆☆ Catalysis Communications 12 (2011) 1224–1227

Electrowetting of ionic liquids (ILs) in different alkane ambient and at different temperatures were studied under different AC voltages. The performance of IL-based electrowetting at elevated temperatures and that at room temperature was compared. It turns out that the electrowetting of ILs at elevated temperatures resulted in faster response and lower operation voltage. Furthermore, the relationship between the structure of the ion and the contact angle change was specifically investigated and theoretically explained. Finally, the properties of IL-based electrowetting in different alkane ambient were studied. It was demonstrated that the long length of the alkyl chain guaranteed a smaller contact angle under the same applied voltage. All the experimental results showed attractive features involving wide operating temperatures and in particular high stability, fast response, and good reversibility at elevated temperatures. The performance of IL-based electrowetting could be further improved through an optimal choice of an ambient phase or a rational design and synthesis of ionic liquids.

Keywords: electrowetting; ionic liquids; temperature; alkanes ambient; AC voltage; response time

★★★☆☆ Hu XD,Zhang SG,Lu XJ,et al. On The Performance Of Thermostable Electrowetting Agents[J]. Surf. Interface Anal.,2011.

Electrocapillarity is the basis of modern electrowetting. And room temperature ionic liquids, an increasingly important set of electrolytes and organic salts that are liquid at room temperature, are considered a novel class of electrowetting agents, because of non-significant vapor pressure, nonflammability, good thermal stability, and a wide useable temperature range. In this paper, a simple device has been fabricated to investigate the electrocapillarity of ionic liquids. It shows attractive features involving wide operating temperature and in particular high stability, fast response and good reversibility at high temperatures. Besides, electrocapillarity of ionic liquids is strongly dependent on power supply frequency. In particular, high frequency, stable, reversible and wide height of rise modulations were obtained. The phenomenon of ionic liquids-based electrocapillarity was found to be affected by the structure and physicochemical properties of ionic liquids such as density, surface tension, alkyl carbon chain length of cation, type of the anion, etc., and the efficiency could be further improved through optimal choice of ambient phase or rational design and synthesis of ionic liquids.

Keywords: Electrocapillarity, ionic liquids, height of rise, response time, high temperature, AC electric fields

★★★☆☆ Hu XD,Zhang SG,Qu C,et al. Electrically Switchable Capillarity Of Ionic Liquids[J]. J. Adhesion Sci. Technol.,2011,0:1-10.

We demonstrated an infrared variable focus ionic liquids lens using electrowetting, which could overcome the problems caused by use of water, e.g., evaporation and poor thermostability, while keeping good optical transparency in visible light and near-infrared region. Besides, the type of lens (convex or concave) could be tuned by applied voltage or refractive index of ILs used, and the transmittance was measured to exceed 90% over the spectrum of visible light and near-infrared. We believe this infrared variable focus ionic liquids lens has a great application prospect in both visible light and infrared image systems.

★★★☆☆ Hu XD,Zhang SG,Liu Y,et al. Electrowetting Based Infrared Lens Using Ionic Liquids[J]. Appl. Phys. Lett.,2011,99:213505(1-3).

A series of new ionic liquids, based on dialkoxy-functionalized quaternary ammonium cations {side chains: 1 = CH3, 1O1 = CH3OCH2, 1O2 =CH3OC2H4, 2O2 = C2H5OC2H4; cations: [N11,1O1,1O2], [N11,1O1,2O2], [N11,1O2,1O2], [N11,1O2,2O2] and [N11,2O2,2O2]}, with BF4 , (CF3SO2)2N (NTf2) and CH3CO2  (OAc) as counteranions, have been prepared and characterized. Their basic properties, such as spectroscopic characteristics, melting point, glass transition temperature, thermal stability, electrochemical window, density, refractive index, viscosity and conductivity, were measured and comparatively studied. The incorporation of two flexible alkoxy chains makes the quaternary ammonium salts highly qualified to be low-viscous and high-conductive room temperature ILs, and even some of them have significantly better fluidity than the popular imidazolium ILs with a similar molecular weight, e.g. [N11,1O1,2O2]BF4 (151 cP and 2.11 mS cm1, Mw: 249) vs. [HMIm]BF4 (220 cP and 1.2 mS cm1, Mw: 256) at 25 ℃. The electrochemical windows of these ILs were evaluated up to 5.5 V. In addition, the dialkoxy OAc ILs were found to have excellent solvent power for cellulose under mild
conditions, e.g. a solution of 18 wt% microcrystalline cellulose in [N11,2O2,2O2]OAc at 80 ℃. By precipitation with water, the dissolved cellulose (I crystal structure) was regenerated as nanosized cellulose II particles with increased surface area and decreased crystallinity, determined by FE-SEM and XRD.

★★★☆☆ NewJ. Chem., 2011, 35, 1596–1606

This work presents ionic liquid based variable focus lenses using electrowetting, which exhibit excellent performance over a conventional saline based lens such as good tolerance of sharp temperature variation, wide operating temperature range (which is up to 100 ℃) and in particular high stability at high temperatures.

★★★☆☆ Hu XD,Zhang SG,Qu C,et al. Ionic Liquid Based Variable Focus Lenses[J]. Soft Matter,2011,7:5941–5943.

Quinolizinium ionic liquids (salts) featuring an unbranched cation core have been prepared, characterized and found to show extremely high fluorescence quantum yields in solution (Ff > 99%, lem near 334 nm) and bright cyan fluorescence in molten state (lem near 465 nm).

★★★☆☆ J. Mater. Chem., 2011, 21, 8979

A new class of liquid fluorescent organic salts was designed and prepared through via a strategy of ionic liquidization. These new ionic liquid materials exhibited strong green fluorescence and remarkable solvent-dependent photoluminescence under UV irradiation. Their physicochemical properties, especially the fluorescent behaviour, were studied intensively.

★★★☆☆ Zhang QH,Yang BQ,Zhang SG,et al. Ionic Liquidized-naphthalenesulfonamide: Successful Fabrication Of Liquid Fluorescent Materials[J]. J. Mater. Chem.,2011,21:16335-16338.

One kind of novel ionic liquids (ILs) with a tertiary amino moiety and a quaternary ammonium group were synthesized and identified by FT-IR, 1H and 13C NMR. The elemental chemical state and basicity of ILs were determined by XPS and Hammett indicator method, respectively. Then the catalytic performance of these bifunctional catalysts was investigated in one-step synthesis of dimethyl carbonate (DMC) from ethylene oxide (EO), carbon dioxide and methanol. The best catalytic performance with 99% EO conversion and a maximum of 74% DMC selectivity was obtained using [N111,6N11]I as catalyst under optimized reaction conditions. And the catalyst could be reused for several times. Normally, stronger basicity could be obtained by altering the anions with different nucleophilicity in ILs and a better catalytic activity could be achieved correspondingly. A mechanism that both the ring opening of epoxide through nucleophilic attacks and the transesterification play an important role in the reaction was proposed based on experimental results.

Keywords Ionic liquid  Bi-functional  One-step synthesis  Dimethyl carbonate  Carbon dioxide

★★★☆☆ Catal Lett (2011) 141:339–346