Effect of Conducting Salts in Ionic Liquid Electrolytes for Enhanced Cyclability of Sodium-Ion Batteries.

The electrochemical performance of ionic liquid electrolytes containing different sodium salts dissolved in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPTFSI) evaluated in a half-cell configuration using spherical P2-NaCoMnO (NCO) cathodes are reported. Among the various electrolytes investigated, sodium bis(fluorosulfonyl)imide (NaFSI) (0.5 M) in BMPTFSI shows the best electrochemical performance with a significant improvement in cycling stability (90% capacity retention after 500 cycles at 50 mA g in a half cell versus Na metal anode) compared with conventional NaClO (1 M) in ethylene carbonate/propylene carbonate electrolytes (39% retention after 500 cycles).

Influence of substituents on cation-anion contacts in imidazolium perrhenates.

A series of imidazolium perrhenates with different substituents at the imidazolium ring were synthesised and characterised, including single crystal X-ray diffraction. The effect of the substitution pattern on the state of aggregation of the compounds, the charge delocalisation and the ion pairing interaction via hydrogen bonds was studied. Particularly the substitution at the C2 position of the imidazolium ring was shown to be crucial to fine-tune the ion contacts.

Catalytic epoxidation by perrhenate through the formation of organic-phase supramolecular ion pairs.

Organic-phase supramolecular ion pair (SIP) host-guest assemblies of perrhenate anions (ReO4(-)) with ammonium amide receptor cations are reported. These compounds act as catalysts for the epoxidation of alkenes by aqueous hydrogen peroxide under biphasic conditions and can be recycled several times with no loss in activity.

Cycloaddition of carbon dioxide and epoxides using pentaerythritol and halides as dual catalyst system.

The combination of pentaerythritol with nucleophilic halide salts such as nBu4NI is used as a dual catalyst system for the cycloaddition of carbon dioxide (CO2) with a broad range of organic epoxides yielding the respective cyclic carbonates. Due to synergistic effects of the organocatalysts, excellent yields and selectivities could be achieved under mild reaction conditions. Moreover, the nontoxic, cost-efficient, and readily available system is easily recyclable without significant loss of reactivity, representing an exceptional sustainable approach for the fixation of CO2.

Cleavage of C-O bonds in lignin model compounds catalyzed by methyldioxorhenium in homogeneous phase.

Methyldioxorhenium (MDO)-catalyzed C-O bond cleavage of a variety of lignin β-O-4-model compounds yields phenolic and aldehydic compounds in homogeneous phase under mild reaction conditions. MDO is in situ generated by reduction of methyltrioxorhenium (MTO) and is remarkably stable under the applied reaction conditions allowing its reuse for least five times without significant activity loss. Based on the observed and isolated intermediates, 17 O- and 2 H-isotope labeling experiments, DFT calculations, and several spectroscopic studies, a reaction mechanism is proposed.