Facile Synthesis of Anhydrous Rare-Earth Trichlorides from their Oxides in Chloridoaluminate Ionic Liquids.

Wide applications of anhydrous rare-earth (RE) trichlorides RECl3 in organometallic chemistry, for the synthesis of optical and magnetic materials, and as catalysts require a facile approach for their synthesis. The known methods use or produce toxic substances, are complicated and have limited reliability and upscaling. It has been shown that task-specific ionic liquids (ILs) can dissolve many metal oxides without special reaction conditions at moderate temperature, making the metals accessible to downstream chemistry. Using imidazolium chloridoaluminate ILs, pure crystalline anhydrous RECl3 (RE=La-Nd, Sm-Dy) can be synthesized in one step from RE oxides in high yield. The Lewis acidic IL acts as solvent and reaction partner. The by-product [Al4 O2 Cl10 ]2- , which was detected spectroscopically, remains in solution. The reacted IL can be removed quantitatively by washing. ILs with various imidazolium cations and AlCl3 content and the effect of temperature and reaction time were tested.

Critical Investigation of Betaine Hydrochloride-Based Deep Eutectic Solvent for Ionometallurgical Metal Production.

The applicability of a deep eutectic solvent (DES) consisting of betainium hydrochloride, urea and glycerol is examined with respect to ionometallurgical metal extraction and compared with the ionic liquid (IL) betainium bis(trifluoromethylsulfonyl)imide ([Hbet][NTf2 ]). The DES dissolves numerous metal oxides, where not only betaine and chloride act as stabilizing ligands, but also nascent ammonia seems to be essential. From such solutions, cobalt, copper, zinc, tin, lead, and even vanadium can be electrodeposited, demonstrating the feasibility of ionometallurgy. However, repeated recycling of the DES is not conceivable. NMR spectroscopy and mass spectrometry identify numerous decomposition reactions taking place at 60 °C already. The by-products that are formed not only make recycling more difficult, but also pose a toxicity problem. The opportunities and obstacles of DESs and ILs for their application in ionometallurgy are critically discussed. It is shown that a thorough understanding of the underlying chemical processes is critical.

Cobalt Deposition from Ionothermally Dissolved Cobalt Oxides.

Owing to the environmental problems of numerous metal production processes, there is a growing need for more energy-efficient approaches. Cobalt is considered a strategic element that is extracted not only from ores but also from spent Li-ion batteries. One promising new approach is ionometallurgy, which is the extraction of metal oxides by ionic liquids (ILs). This study concerns new investigations into ionometallurgical processing of CoO, Co3 O4 , and LiCoO2 in the IL betainium bis(trifluoromethylsulfonyl)imide, [Hbet][NTf2 ]. Three crystal structures of cobalt-betaine complex compounds and combined spectroscopic and diffraction studies provide insights into the dissolution process. In addition, an optimized dissolution procedure for metal oxides is presented, avoiding the previously reported decomposition of the IL. Subsequent cobalt electrodeposition is only possible from cationic complex species, highlighting the importance of a thorough understanding of the complex equilibria. The presented method is also compared to other recently reported approaches.

Processing Gray Selenium in Phosphonium-Based Ionic Liquids.

The dissolution of gray selenium in tetraalkylphosphonium acetate ionic liquids was investigated by UV-vis, NMR, and Raman spectroscopy as well as quantum chemical calculations and electrochemical methods. Acetate anions and tetraalkylphosphonium cations facilitate the formation and stabilization of oligoselenides Sen2- and cationic Se species in the ionic liquid phase. Chemical exchange of selenium atoms was demonstrated by variable-temperature 77Se NMR experiments. Additionally, uncharged cycloselenium molecules exist at high selenium concentrations. Upon dilution with ethanol, amorphous red selenium precipitates from the solution. Moreover, crystalline Se1-xTex solid solutions precipitate when elemental tellurium is added to the mixture as confirmed by powder X-ray diffraction and Raman spectroscopy.

Electrolyte for High-Energy- and Power-Density Zinc Batteries and Ion Capacitors.

Growth of dendrites, limited coulombic efficiency (CE), and the lack of high-voltage electrolytes restrict the commercialization of zinc batteries and capacitors. These issues are resolved by a new electrolyte, based on the zinc(II)-betaine complex [Zn(bet)2 ][NTf2 ]2 . Solutions in acetonitrile (AN) avoid dendrite formation. A Zn||Zn cell operates stably over 10 110 h (5055 cycles) at 0.2 mA cm-2 or 110 h at 50 mA cm-2 , and has an area capacity of 113 mAh cm-2 at 80% depth of discharge. A zinc-graphite battery performs at 2.6 V with a midpoint discharge-voltage of 2.4 V. The capacity-retention at 3 A g-1 (150 C) is 97% after 1000 cycles and 68% after 10 000 cycles. The charge/discharge time is about 24 s at 3.0 A g-1 with an energy density of 49 Wh kg-1 at a power density of 6864 W kg-1 based on the cathode. A zinc||activated-carbon ion-capacitor (coin cell) exhibits an operating-voltage window of 2.5 V, an energy density of 96 Wh kg-1 with a power density of 610 W kg-1 at 0.5 A g-1 . At 12 A g-1 , 36 Wh kg-1 , and 13 600 W kg-1 are achieved with 90% capacity-retention and an average CE of 96% over 10 000 cycles. Quantum-chemical methods and vibrational spectroscopy reveal [Zn(bet)2 (AN)2 ]2+ as the dominant complex in the electrolyte.

High molecular diversity in the functional group of small bacterivorous non-scaled chrysomonad flagellates.

"Spumella"-like flagellates describes similar or even indiscernible colourless non-scaled chrysophytes which are important bacterivores common in different aquatic ecosystems. Recently, phylogenetic analyses revealed a high taxonomic diversity of these flagellates leading to the description of several new genera and species. Our present work on the functional group of pelagic bacterivorous chrysomonads from different water bodies resulted in an extended taxonomic analysis among chrysophytes unveiling yet undescribed genera and species pointing to the high hidden diversity of bacterivores in the pelagial of freshwaters. On the basis of phylogenetic analyses, we describe four new genera Atacamaspumella, Chlorospumella, Pseudapoikia, and Vivaspumella and a new species of the recently described genus Poteriospumella. Beside this, we redescribe the species Ochromonas vasocystis Doflein, 1923 to Poteriospumella vasocystis comb. nov. substantiated on the high sequence similarity with Poteriospumella lacustris Boenigk et Findenig and Poteriospumella maldiviensis nov. sp.

Intrinsic nonlinear dynamics drive single-species systems.

The importance of oscillations and deterministic chaos in natural biological systems has been discussed for several decades and was originally based on discrete-time population growth models (May 1974). Recently, all types of nonlinear dynamics were shown for experimental communities where several species interact. Yet, there are no data exhibiting the whole range of nonlinear dynamics for single-species systems without trophic interactions. Up until now, ecological experiments and models ignored the intracellular dimension, which includes multiple nonlinear processes even within one cell type. Here, we show that dynamics of single-species systems of protists in continuous experimental chemostat systems and corresponding continuous-time models reveal typical characteristics of nonlinear dynamics and even deterministic chaos, a very rare discovery. An automatic cell registration enabled a continuous and undisturbed analysis of dynamic behavior with a high temporal resolution. Our simple and general model considering the cell cycle exhibits a remarkable spectrum of dynamic behavior. Chaos-like dynamics were shown in continuous single-species populations in experimental and modeling data on the level of a single type of cells without any external forcing. This study demonstrates how complex processes occurring in single cells influence dynamics on the population level. Nonlinearity should be considered as an important phenomenon in cell biology and single-species dynamics and also, for the maintenance of high biodiversity in nature, a prerequisite for nature conservation.

A Kinetically Superior Rechargeable Zinc-Air Battery Derived from Efficient Electroseparation of Zinc, Lead, and Copper in Concentrated Solutions.

Zinc electrodeposition is currently a hot topic because of its widespread use in rechargeable zinc-air batteries. However, Zn deposition has received little attention in organic solvents with much higher ionic conductivity and current efficiency. In this study, a Zn-betaine complex is synthesized by using ZnO and betainium bis[(trifluoromethyl)sulfonyl]imide and its electrochemical behavior for six organic solvents and electrodeposited morphology are studied. Acetonitrile allowed dendrite-free Zn electrodeposition at room temperature with current efficiencies of up to 86 %. From acetonitrile solutions in which Zn, Pb, and Cu complexes are dissolved in high concentrations, Zn and Pb/Cu are efficiently separated electrolytically under potentiostatic control, allowing the purification of solutions prepared directly from natural ores. Additionally, a highly flexible Zn anode with excellent kinetics is obtained by using a carbon fabric substrate. A rechargeable zinc-air battery with these electrodes shows an open-circuit voltage of 1.63 V, is stable for at least 75 cycles at 0.5 mA cm-2 or 33 cycles at 20 mA cm-2 , and allows intermediate cycling at 100 mA cm-2 .

Exploration of metal sulfide syntheses and the dissolution process of antimony sulfide in phosphonium-based ionic liquids.

Ionic liquids (ILs), especially task-specific ILs, are capable of dissolving various solids at moderate temperatures without the need for special reaction vessels. Direct synthesis of binary sulfides of B, Bi, Ge, Mo, Cu, Au, Sn, In, Ti, V, Fe, Co, Ga, Ni, Al, Zn, and Sb in [P66614]Cl was tested at 100 °C, i.e. below the melting point of sulfur. Under these conditions, substantial sulfide formation occurred only for nickel (Ni3S4, Ni3S2, NiS) and copper (Cu2S, CuS). Sb showed no formation of crystalline sulfide, but after addition of EtOH, an orange material precipitated which was identified as amorphous metastibnite. Subsequently, the dissolution of antimony sulfide (Sb2S3), the main source of antimony production, in the phosphonium-based ILs [P66614][OAc] and [P66614]Cl at 100 °C was studied in detail. The dissolution proceeds without H2S evolution, and amorphous Sb2S3 can be precipitated from these solutions. Heating Sb2S3 in the Lewis-acidic IL [BMIm]Cl·4.7AlCl3 led to the crystallization of [Sb13S16Cl2][AlCl4]5, which contains a new quadruple heterocubane cation.

Coexistence of Tellurium Cations and Anions in Phosphonium-Based Ionic Liquids.

Elemental tellurium readily dissolves in ionic liquids (ILs) based on tetraalkylphosphonium cations even at temperatures below 100 °C. In the case of ILs with acetate, decanoate, or dicyanamide anions, dark red to purple colored solutions form. A study combining NMR, UV-Vis and Raman spectroscopy revealed the formation of tellurium anions (Ten )2- with chain lengths up to at least n=5, which are in dynamic equilibrium with each other. Since external influences could be excluded and no evidence of an ionic liquid reaction was found, disproportionation of the tellurium is the only possible dissolution mechanism. Although the spectroscopic detection of tellurium cations in these solutions is difficult, the coexistence of tellurium cations, such as (Te4 )2+ and (Te6 )4+ , and tellurium anions could be proven by cyclic voltammetry and electrodeposition experiments. DFT calculations indicate that electrostatic interactions with the ions of the ILs are sufficient to stabilize both types of tellurium ions in solution.

Ionometallurgical Step-Electrodeposition of Zinc and Lead and its Application in a Cycling-Stable High-Voltage Zinc-Graphite Battery.

Ionometallurgy is a new development aiming at the sustainable low-temperature conversion of naturally occurring metal ores and minerals to their metals or valuable chemicals in ionic liquids (ILs) or deep eutectic solvents. The IL betainium bis((trifluoromethyl)sulfonyl)imide, [Hbet][NTf2 ], is especially suited for this process due to its redox-stability and specific-functionalization. The potentiostatic electrodeposition of zinc and lead starting directly from ZnO and PbO, which dissolve in [Hbet][NTf2 ] in high concentrations is reported. The initial reduction potentials of zinc(II) and lead(II) are about -1.5 and -1.0 V, respectively. The ionic conductivity of the solution of ZnO in [Hbet][NTf2 ] is measured and the effect of various temperatures and potentials on the morphology of the deposited material is explored. The IL proves to be stable under the chosen conditions. From IL-solutions, where ZnO, PbO, and MgO have been dissolved, metallic Zn and Pb are deposited under potentiostatic control either consecutively by step-electrodeposition or together in a co-electrodeposition. Using the method, Zn is also deposited on 3D copper foam and assembles into high-voltage zinc-graphite battery. It exhibits a working-voltage up to 2.7 V, an output midpoint discharge-voltage of up to 2.16 V, up to 98.6% capacity-retention after 150 cycles, and good rate performance.

Metal Assisted Synthesis of Cationic Sulfidobismuth Cubanes in Ionic Liquids.

Invited for this month's cover is the group of Michael Ruck at the Technische Universität Dresden (Germany). The cover picture shows the spiro-dicubane Bi7 S8 5+ in the center, accompanied by two Bi4 S4 4+ hetero-cubanes on both sides, which are shown along their threefold axis. These sulfidobismuth polycations were isolated in salts with [AlCl4 ]- and [S(AlCl3 )3 ]2- anions. The starting material was Bi2 S3 , which is generally hard to dissolve but can easily be activated under ionothermal conditions. Moreover, the presence of noble metal ions, such as Ag+ , Au+ or Pt2+ , played a crucial role for the formation of those compounds. This research was performed in the framework of the Priority Program SPP 1708 "Material Synthesis Near Room Temperature" of the German Research Council (DFG). Read the full text of their Full Paper at 10.1002/open.202000246.

Low Temperature Activation of Tellurium and Resource-Efficient Synthesis of AuTe2 and Ag2 Te in Ionic Liquids.

The low temperature syntheses of AuTe2 and Ag2 Te starting from the elements were investigated in the ionic liquids (ILs) [BMIm]X and [P66614 ]Z ([BMIm]+ =1-butyl-3-methylimidazolium; X = Cl, [HSO4 ]- , [P66614 ]+ = trihexyltetradecylphosphonium; Z = Cl- , Br- , dicyanamide [DCA]- , bis(trifluoromethylsulfonyl)imide [NTf2 ]- , decanoate [dec]- , acetate [OAc]- , bis(2,4,4-trimethylpentyl)phosphinate [BTMP]- ). Powder X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy revealed that [P66614 ]Cl is the most promising candidate for the single phase synthesis of AuTe2 at 200 °C. Ag2 Te was obtained using the same ILs by reducing the temperature in the flask to 60 °C. Even at room temperature, quantitative yield was achieved by using either 2 mol % of [P66614 ]Cl in dichloromethane or a planetary ball mill. Diffusion experiments, 31 P and 125 Te-NMR, and mass spectroscopy revealed one of the reaction mechanisms at 60 °C. Catalytic amounts of alkylphosphanes in commercial [P66614 ]Cl activate tellurium and form soluble phosphane tellurides, which react on the metal surface to solid telluride and the initial phosphane. In addition, a convenient method for the purification of [P66614 ]Cl was developed.

Metal Assisted Synthesis of Cationic Sulfidobismuth Cubanes in Ionic Liquids.

Bi2 S3 was dissolved in the presence of either AuCl/PtCl2 or AgCl in the ionic liquids [BMIm]Cl ⋅ xAlCl3 (BMIm=1-n-butyl-3-methylimidazolium; x=4-4.3) through annealing the mixtures at 180 or 200 °C. Upon cooling to room temperature, orange, air-sensitive crystals of [BMIm](Bi4 S4 )[AlCl4 ]5 (1) or Ag(Bi7 S8 )[S(AlCl3 )3 ]2 [AlCl4 ]2 (2) precipitated, respectively. 1 did not form in the absence of AuCl/PtCl2 , suggesting an essential role of the metal cations. X-ray diffraction on single-crystals of 1 revealed a monoclinic crystal structure that contains (Bi4 S4 )4+ heterocubanes and [AlCl4 ]- tetrahedra as well as [BMIm]+ cations. The intercalation of the ionic liquid was confirmed via solid state NMR spectroscopy, revealing unusual coupling behavior. The crystal structure of 2 consists of (Bi7 S8 )5+ spiro-dicubanes, [S(AlCl3 )3 ]2- tetrahedra triples, isolated [AlCl4 ]- tetrahedra, and heavily disordered silver(I) cations. No cation ordering took place in 2 upon slow cooling to 100 K.

Resource-Efficient Low-Temperature Synthesis of Microcrystalline Pb2 B5 O9 X (X = Cl, Br) for Surfaces Studies by Optical Second Harmonic Generation.

Optically nonlinear Pb2 B5 O9 X (X = Cl, Br) borate halides are an important group of materials for second harmonic generation (SHG). Additionally, they also possess excellent photocatalytic activity and stability in the process of dechlorination of chlorophenols, which are typical persistent organic pollutants. It would be of great interest to conduct in situ (photo-) catalysis investigations during the whole photocatalytic process by SHG when considering them as photocatalytic materials. In order to get superior photocatalytic efficiency and maximum surface information, small particles are highly desired. Here, a low-cost and fast synthesis route that allows growing microcrystalline optically nonlinear Pb2 B5 O9 X borate halides at large quantities is introduced. When applying the ionothermal growth process at temperatures between 130 and 170 °C, microcrystallites with an average size of about 1 µm precipitate with an orthorhombic hilgardite-like borate halide structure. Thorough examinations using powder X-ray diffraction and scanning electron microscopy, the Pb2 B5 O9 X microcrystals are indicated to be chemically pure and single-phased. Besides, the Pb2 B5 O9 X borate halides' SHG efficiencies are confirmed using confocal SHG microscopy. The low-temperature synthesis route thus makes these borate halides a highly desirable material for surface studies such as monitoring chemical reactions with picosecond time resolution and in situ (photo-) catalysis investigations.

One-pot resource-efficient synthesis of SnSb powders for composite anodes in sodium-ion batteries.

SnSb alloy, which can be used as an anode in a sodium-ion cell, was synthesized following a resource-efficient route at low temperature. This one-pot approach greatly reduces the energy consumption and maximizes the efficient use of raw materials. The reaction of elemental tin and antimony in the ionic liquid (IL) trihexyltetradecylphosphonium chloride ([P66614]Cl) at 200 °C led to a microcrystalline powder of single-phase SnSb within 10 h with very high yield (95%). Liquid-state nuclear magnetic resonance spectroscopy revealed that the IL remains essentially stable during the reaction. It was recovered almost quantitatively by distilling off the organic solvent used for product separation. Composites of SnSb powder and carbon nanotubes (CNTs) were fabricated by a simple ball milling process. Electrochemical measurements demonstrate that the Na‖SnSb/CNTs cell retains close to 100% of its initial capacity after 50 cycles at a current of 50 mA g-1, which is much better than the Na‖SnSb cell. The greatly increased capacity retainability can be attributed to the conductive network formed by CNTs inside the SnSb/CNTs electrode, providing 3D effective and fast electronic pathways during sodium intercalation and de-intercalation.