TY - JOUR A1 - Usmani, Shirin A1 - Stephan, Ina A1 - Huebert, Thomas A1 - Kemnitz, E. T1 - Nano metal fluorides for wood protection against fungi N2 - Wood treated with nano metal fluorides is found to resist fungal decay. Sol−gel synthesis was used to synthesize MgF2 and CaF2 nanoparticles. Electron microscopy images confirmed the localization of MgF2 and CaF2 nanoparticles in wood. Efficacy of nano metal fluoride-treated wood was tested against brown-rot fungi Coniophora puteana and Rhodonia placenta. Untreated wood specimens had higher mass losses (∼30%) compared to treated specimens, which had average mass loss of 2% against C. puteana and 14% against R. placenta, respectively. Nano metal fluorides provide a viable alternative to current wood preservatives. KW - Brown-rot fungi KW - Coniophora puteana KW - Fluoride nanoparticles KW - Fluorolytic sol−gel KW - Rhodonia placenta KW - SEM wood characterization KW - Wood protection PY - 2018 DO - https://doi.org/10.1021/acsanm.8b00144 SN - 2574-0970 VL - 2018 SP - 1 EP - 6 PB - American Chemical Society (ACS) CY - Washington DC, US AN - OPUS4-44730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Breitfeld, Steffen A1 - Scholz, G. A1 - Emmerling, Franziska A1 - Kemnitz, E. T1 - BaF-benzenedicarboxylate: the first mechanochemical N2 - Anewbariumcoordination polymer, BaF-benzenedicarboxylate (BaF(p-BDC)0.5), with fluorine directly coordinated to the metal cation, was prepared by mechanochemical synthesis routes. Phase-pure BaF-benzenedicarboxylate was synthesized by milling starting either from barium hydroxide or from Barium acetate as sources for barium cations. In both cases, the second reactant was 1,4-benzenedicarboxylic acid (H2(p-BDC)). Ammonium fluoride was used as fluorinating agent directly at milling. This is the first mechanochemical synthesis of coordination polymers where fluorine is directly coordinated to the metal cation. Following the second possibility, barium acetate fluoride (Ba(OAc)F) is formed as ntermediate product after milling, and the new coordination polymer is accessible only after washing with water and dimethyl sulfoxide. The new compound BaF(p-BDC)0.5 was characterized by X-ray powder diffraction, FTIR-, and 19F, 1H-13C CP MAS NMR spectroscopies, DTA-TG, and elemental Analysis. KW - Milling KW - MOF PY - 2018 DO - https://doi.org/10.1007/s10853-018-2331-3 SN - 0022-2461 VL - 53 IS - 19 SP - 13682 EP - 13689 PB - Springer AN - OPUS4-45677 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Usmani, S. A1 - Voss, L. A1 - Stephan, Ina A1 - Hübert, Thomas A1 - Kemnitz, E. T1 - Improved Durability of Wood Treated with Nano Metal Fluorides against Brown-Rot and White-Rot Fungi N2 - Low-water soluble metal fluorides such as magnesium fluoride (MgF2) and calcium Fluoride (CaF2) were evaluated for decay protection of wood. Initially, the biocidal efficacy of nano metal fluorides (NMFs) against wood destroying fungi was assessed with an in-vitro agar test. The results from the test showed that agar medium containing MgF2 and CaF2 was more efficient in preventing fungal decay than stand-alone MgF2 or CaF2. These metal fluorides, in their nanoscopic form synthesized using fluorolytic sol-gel synthesis, were introduced into the sapwood of Scots pine and beech wood and then subjected to accelerated ageing by leaching (EN 84). MAS 19F NMR and X-ray micro CT images showed that metal fluorides were present in treated wood, unleached and leached. Decay resistance of Scots pine and beech wood treated with NMFs was tested against Wood destroying fungi Rhodonia placenta and Trametes versicolor in accordance with EN 113. Results revealed that mass losses were reduced to below 3% in wood treated with the combination of MgF2 and CaF2. It is concluded that NMFs provide full protection to wood even after it has been leached and can be used as wood preservatives in outdoor environments. KW - Nanoparticles KW - Fluoride KW - Wood protection KW - Fluorolytic sol-gel synthesis KW - Brown-rot fungi KW - White-rot fungi KW - Basidiomycetes PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543877 DO - https://doi.org/10.3390/app12031727 VL - 12 IS - 3 SP - 1 EP - 11 PB - MDPI AN - OPUS4-54387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guo, Y. A1 - Lippitz, Andreas A1 - Saftien, P. A1 - Unger, Wolfgang A1 - Kemnitz, E. T1 - Tuning the surface properties of novel ternary iron(III) fluoride-based catalysts using the template effect of the matrix N2 - Sol–gel prepared ternary FeF3–MgF2 materials have become promising heterogeneous catalysts due to their porosity and surface Lewis/Brønsted acidity (bi-acidity). Despite the good catalytic performance, nanoscopic characterisations of this type of material are still missing and the key factors controlling the surface properties have not yet been identified, impeding both a better understanding and further development of ternary fluoride catalysts. In this study, we characterised the interaction between the bi-acidic component (FeF3) and the matrix (MgF2) on the nano-scale. For the first time, the formation pathway of FeF3–MgF2 was profiled and the template effect of MgF2 during the synthesis process was discovered. Based on these new insights two novel materials, FeF3–CaF2 and FeF3–SrF2, were established, revealing that with decreasing the atomic numbers (from Sr to Mg), the ternary fluorides exhibited increasing surface acidity and surface area but decreasing pore size. These systematic changes gave rise to a panel of catalysts with tuneable surface and bulk properties either by changing the matrix alkaline earth metal fluoride or by adjusting their ratios to Fe or both. The template effect of the alkaline earth metal fluoride matrix was identified as the most probable key factor determining the surface properties and further influencing the catalytic performance in ternary fluoride based catalysts, and paves the way to targeted design of next-generation catalysts with tunable properties. KW - Catalysis KW - Surface analysis KW - XPS PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-327410 DO - https://doi.org/10.1039/c4dt03229b SN - 1477-9226 SN - 1477-9234 SN - 1364-5447 VL - 44 IS - 11 SP - 5076 EP - 5085 PB - RSC CY - Cambridge AN - OPUS4-32741 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 - TY - JOUR A1 - Krüger, Hannes A1 - Kemnitz, E. A1 - Hertwig, Andreas A1 - Beck, Uwe T1 - Transparent MgF2-films by sol-gel coating: Synthesis and optical properties N2 - Dielectric, anti-reflective or high reflective systems consist of low and high refractive index layers. Common systems are oxides. The preparation of low refractive index MgF2-films of optical quality by means of an anhydrous low temperature sol–gel synthesis is presented. The MgF2-sol is prepared by spin-coating on silicon and glass substrates. Various film thicknesses between 20 nm and 435 nm have been deposited. It has been shown that the thickness increase is proportional to the number of coating steps. The deposited MgF2-films consist of 10 nm to 20 nm large nanoparticles and have smooth surfaces with an average roughness (Ra) of (1.7 ± 0.3) nm. The optical constants n and k of the films are in agreement with the literature data of bulk-MgF2. KW - Sol-gel KW - Nano-MgF2 KW - Spin coating KW - Optical properties KW - Nanoparticles PY - 2008 DO - https://doi.org/10.1016/j.tsf.2007.10.126 SN - 0040-6090 VL - 516 IS - 12 SP - 4175 EP - 4177 PB - Elsevier CY - Amsterdam AN - OPUS4-17375 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Hannes A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Kemnitz, E. T1 - Low temperature sol-gel metal oxide and fluoride layer stacks for optical applications N2 - MgF2 and TiO2 single layers and layer stacks were produced by a spin-coating sol-gel process. The final temperature treatment was carried out at 100 °C. The layers were deposited onto silicon and fused silica substrates and were analysed by means of atomic force microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, ellipsometry, and UV-vis transmission spectroscopy. MgF2 and TiO2 single layers have morphological and optical properties comparable with physical vapour deposited layers. By using spectroscopic mapping ellipsometry, a good inter- and intra-sample homogeneity was confirmed. Multiple deposition steps result in a linear increase of layer thickness. Various films were deposited with thicknesses between 25 nm and 350 nm. It was shown that the low temperature sol-gel process results in films of optical quality. Anti-reflective and high reflective layer stacks consisting of MgF2 and TiO2 were designed and can be produced now by a sol-gel process, whereas the MgF2 layers in the layer stacks contains also traces of MgF2-2xOx. KW - Magnesium fluoride KW - Titanium oxide KW - Sol-gel KW - Spin-coating KW - Optical properties KW - Optical layer stacks KW - MgF2 KW - TiO2 PY - 2010 DO - https://doi.org/10.1016/j.tsf.2010.06.025 SN - 0040-6090 VL - 518 IS - 21 SP - 6080 EP - 6086 PB - Elsevier CY - Amsterdam AN - OPUS4-21516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - König, R. A1 - Scholz, G. A1 - Kemnitz, E. T1 - Crystalline aluminium hydroxy fluorides: Structural insights obtained by high field solid state NMR and 27Al chemical shift trend analysis T2 - Gesellschaft Deutscher Chemiker CY - Regensburg, Germany DA - 2008-09-22 PY - 2008 AN - OPUS4-17956 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - König, R. A1 - Scholz, G. A1 - Kemnitz, E. T1 - Crystalline aluminium hydroxyl fluorides: Structural insights obtained by high-field solid state NMR and 27Al chemical shift trend analysis T2 - Gesellschaft Deutscher Chemiker CY - Regensburg, Germany DA - 2008-09-22 PY - 2008 AN - OPUS4-17957 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Hannes A1 - Kemnitz, E. A1 - Hertwig, Andreas A1 - Beck, Uwe T1 - Moderate temperature sol-gel deposition of magnesium fluoride films for optical UV-applications: A study on homogeneity using spectroscopic ellipsometry N2 - Thin films of MgF2 have been deposited on silicon wafers in optical quality with a novel sol-gel deposition process at temperatures as low as 100 °C. The properties of the fluoride layers are compared to bulk MgF2 with respect to the optical constants. By employing spectroscopic mapping ellipsometry, the uniformity of the thickness of fluoride layers is confirmed to be within acceptable limits for optical applications. The optical constants are close to the bulk data. High-quality low-index films of suitable and homogeneous thickness have already been produced on a laboratory scale. KW - 78.20.-e KW - 78.66.Li KW - 78.68.+m KW - 81.20.Fw PY - 2008 DO - https://doi.org/10.1002/pssa.200777856 SN - 1862-6300 SN - 0031-8965 VL - 205 IS - 4 SP - 821 EP - 824 PB - Wiley-VCH CY - Berlin AN - OPUS4-17330 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -