2015, Knorr, Anne, Ludwig, Ralf

Direct spectroscopic evidence for H-bonding between like-charged ions is reported for the ionic liquid, 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate. New infrared bands in the OH frequency range appear at low temperatures indicating the formation of H-bonded cation-cation clusters similar to those known for water and alcohols. Supported by DFT calculations, these vibrational bands can be assigned to attractive interaction between the hydroxyl groups of the cations. The repulsive Coulomb interaction is overcome by cooperative hydrogen bonding between ions of like charge. The transition energy from purely cation-anion interacting configurations to those including cation-cation H-bonds is determined to be 3–4 kJmol−1. The experimental findings and DFT calculations strongly support the concept of anti-electrostatic hydrogen bonds (AEHBs) as recently suggested by Weinhold and Klein. The like-charge configurations are kinetically stabilized with decreasing temperatures.

2011, Surkus, Annette-Enrica, Junge, Henrik

[no abstract available]

2014, Steinfeldt, Norbert

[no abstract available]

2014, Martin, Andreas, Wohlrab, Sebastian

[no abstract available]

2020, Shen, Huidong, Peppel, Tim, Strunk, Jennifer, Sun, Zhenyu

Photocatalytic CO2 reduction to produce valuable chemicals and fuels using solar energy provides an appealing route to alleviate global energy and environmental problems. Searching for photocatalysts with high activity and selectivity for CO2 conversion is the key to achieving this goal. Among the various proposed photocatalysts, metal-free materials, such as graphene, nitrides, carbides, and conjugated organic polymers, have gained extensive research interest for photocatalytic CO2 reduction, due to their earth abundance, cost-effectiveness, good electrical conductivity, and environmental friendliness. They exhibit prominent catalytic activity, impressive selectivity, and long durability for the conversion of CO2 to solar fuels. Herein, the recent progress on metal-free photocatalysis of CO2 reduction is systematically reviewed. Opportunities and challenges on modification of nonmetallic catalysts to enhance CO2 transformation are presented. Theoretical calculations on possible reduction mechanisms and pathways as well as the potential in situ and operando techniques for mechanistic understanding are also summarized and discussed. Based on the aforementioned discussions, suitable future research directions and perspectives for the design and development of potential nonmetallic photocatalysts for efficient CO2 reduction are provided. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

2014, Martin, Andreas, Meier, Dietrich

[no abstract available]

2012, Kugler, Michael, Baumann, Franz-Erich, Fehrenbacher, Ulrich, Fridag, Dirk, Köckritz, Angela, Petrat, Frank-Martin, Tübke, Beatrice, Walter, Guido

[no abstract available]

2019, Schneekönig, Jacob, Junge, Kathrin, Beller, Matthias

The asymmetric transfer hydrogenation of ketones using isopropyl alcohol (IPA) as hydrogen donor in the presence of novel manganese catalysts is explored. The selective and active systems are easily generated in situ from [MnBr(CO)5] and inexpensive C 2-symmeric bisoxalamide ligands. Under the optimized reaction conditions, the Mn-derived catalyst gave higher enantioselectivity compared with the related ruthenium catalyst.

2011, Neumann, M., Nöske, R., Bach, G., Glaubauf, T., Bartoszek, M., Strauch, P.

An efficient, reliable and low-cost procedure to determine the silicon content in plant material is presented which allows to monitor the agricultural aspects like growth and yield. The presented procedure consists of a hydrochloric acid pre-treatment and a subsequent thermal oxidation. The method is compared to other processes like dissolution in hydrofluoric acid combined with ICP OES, energy-dispersive X-ray fluorescence spectroscopy (EDXRF) or aqua regia treatment.

2013, LIKAT

[no abstract available]