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.     

Triphilic pentablock copolymers with perfluoroalkyl segment in central position

Adding perfluoroalkyl (PF) segments to amphiphilic copolymers yields triphilic copolymers with new application profiles. Usually, PF segments are attached as terminal blocks via Cu(I) catalyzed azide-alkyne cycloaddition (CuAAC). The purpose of the current study is to design new triphilic architectures with a PF segment in central position. The PF segment bearing bifunctional atom transfer radical polymerization (ATRP) initiator is employed for the fabrication of triphilic poly(propylene oxide)-b-poly(glycerol monomethacrylate)-b-PF-b-poly(glycerol monomethacrylate)-b-poly(propylene oxide) PPO-b-PGMA-b-PF-b-PGMA-b-PPO pentablock copolymers by a combined ATRP and CuAAC reaction approach. Differential scanning calorimetry indicates the PF-initiator to undergo a solid–solid phase transition at 63°C before the final crystal melting at 95°C. This is further corroborated by polarized optical microscopy and X-ray diffraction studies. The PF-initiator could successfully polymerize solketal methacrylate (SMA) under typical ATRP conditions producing well-defined Br-PSMA-b-PF-b-PSMA-Br triblock copolymers that are then converted into PPO-b-PSMA-b-PF-b-PSMA-b-PPO pentablock copolymer via CuAAC reaction. Subsequently, acid hydrolysis of the PSMA blocks afforded water soluble well-defined triphilic pentablock copolymers PPO-b-PGMA-b-PF-b-PGMA-b-PPO with fluorophilic central segment, hydrophilic middle blocks, and lipophilic outer blocks. The triphilic block copolymers could self-assemble, depending upon the preparatory protocol, into spherical and filament-like phase-separated nanostructures as revealed by transmission electron microscopy.     

Complex powers of classical SG-pseudodifferential operators

Abstract Under a suitable ellipticity condition, we show that classical SG-pseudodifferential operators of nonnegative order possess complex powers. We show that the powers are again classical and derive an explicit formula for all homogeneous components. Keywords: Complex power, Weighted symbols, Noncompact manifolds     

<Emphasis Type="Italic">J/Ψ</Emphasis>production

For more than 25 yearsJΨ production has helped to sharpen our understanding of QCD. In proton induced reaction some observations are rather well understood while others are still unclear. The current status of the theory ofJΨ production will be sketched, paying special attention to the issues of formation time andJΨ re-interaction in a nuclear medium.     

Tribute to Endre Csáki and Pál Révész

Summary This article provides a glimpse of some of the highlights of the joint work of Endre Csáki and Pál Révész since 1979. The topics of this short exploration of the rich stochastic milieu of this inspiring collaboration revolve around Brownian motion, random walks and their long excursions, local times and additive functionals, iterated processes, almost sure local and global central limit theorems, integral functionals of geometric stochastic processes, favourite sites--favourite values and jump sizes for random walk and Brownian motion, random walking in a random scenery, and large void zones and occupation times for coalescing random walks.