TY - JOUR A1 - Conrad, R. A1 - Klose, M. A1 - Noll, Matthias A1 - Kemnitz, D. A1 - Bodelier, P.L.E. T1 - Soil type links microbial colonization of rice roots to methane emission N2 - Most of the methane (CH4) emission from rice fields is derived from plant photosynthates, which are converted to CH4. Rice cluster I (RC-1) archaea colonizing the rhizosphere were found to be the methanogens responsible for this process. Hence, RC-1 methanogens seem to play a crucial role in emission of the greenhouse gas CH4. We determined the community composition and activity of methanogens colonizing the roots of eight different rice cultivars after growth on both Italian rice soil and river bank soil, which contained different communities of methanogenic archaea. The community composition was analyzed by terminal restriction fragment length polymorphism and cloning/sequencing of the archaeal 16S rRNA gene and the mcrA gene coding for a subunit of the methyl coenzyme M reductase. When grown on rice field soil, the methanogenic community of the different rice cultivars was always dominated by RC-1 methanogens. In contrast, roots were colonized by Methanomicrobiales when grown on river bank soil, in which RC-1 methanogens were initially not detectable. Roots colonized with Methanomicrobiales compared with RC-1 exhibited lower CH4 production and CH4 emission rates. The results show that the type of methanogens colonizing rice roots has a potentially important impact on the global CH4 cycle. KW - Gene sequence KW - Methane emission KW - Methanomicrobiales KW - Methyl coenzyme M reductase KW - Ribosomal RNA KW - Rice cluster I KW - Rice cultivar KW - Rice field soil KW - Rice root KW - Terminal restriction fragment length polymorphism PY - 2008 DO - https://doi.org/10.1111/j.1365-2486.2007.01516.x SN - 1354-1013 SN - 1365-2486 VL - 14 IS - 3 SP - 657 EP - 669 PB - Blackwell Science CY - Oxford AN - OPUS4-16517 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - König, R. A1 - Scholz, G. A1 - Scheurell, K. A1 - Heidemann, D. A1 - Buchem, I. A1 - Unger, Wolfgang A1 - Kemnitz, E. T1 - Spectroscopic characterization of crystalline AIF3 phases N2 - A comprehensive spectroscopic characterization of all known crystalline AlF3 phases (α-, β-, η-, κ-, θ-AlF3) is presented for the first time in this study. Beside their X-ray diffraction powder patterns, which were already published in the literature, 27Al and 19F MAS NMR, FT IR and XPS spectroscopic techniques were applied for all phases in a consistent manner. For all phases prepared the utilization of 27Al satellite transition (SATRAS) NMR allowed to determine the quadrupolar parameters of the aluminium sites including their distributions. In addition, η-AlF3 was isolated with high phase purity and characterized following a new preparation path different from those known so far in the literature. KW - Crystalline aluminium fluorides KW - Solid state NMR KW - FT IR KW - XPS PY - 2010 DO - https://doi.org/10.1016/j.jfluchem.2009.10.015 SN - 0022-1139 SN - 1873-3328 VL - 131 IS - 1 SP - 91 EP - 97 PB - Elsevier CY - Amsterdam AN - OPUS4-20991 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meißner, G. A1 - Dirican, D. A1 - Jäger, Christian A1 - Braun, T. A1 - Kemnitz, E. T1 - Et3GeH versus Et3SiH: controlling reaction pathways in catalytic C–F bond activations at a nanoscopic aluminum chlorofluoride† N2 - Catalytic C–F bond activation reactions of mono- and polyfluoroalkanes at Lewis acidic amorphous aluminum chlorofluoride (ACF) are presented. The hydrogen sources Et3GeH or Et3SiH control the selectivity of the conversions. The immobilization of Et3GeH at ACF resulted in catalytic dehydrohalogenation reactions to yield olefins under very mild conditions. In contrast, if Et3SiH is immobilized at ACF, C–C coupling occured and the formation of Friedel–Crafts products was observed. MAS NMR spectroscopic studies revealed information about the surface binding of the substrates. KW - Vapor-phase hydrofluorination KW - Carbon-fluorine bonds KW - Vinyl fluoride KW - Phosphine-ligands KW - Room-temperature KW - Building-blocks KW - Etal-complexes KW - Germylium ions KW - Lewis-acids KW - Hydrodefluorination PY - 2017 DO - https://doi.org/10.1039/c7cy00845g SN - 2044-4753 SN - 2044-4761 VL - 7 IS - 15 SP - 3348 EP - 3354 PB - The Royal Society of Chemistry AN - OPUS4-41836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -