TY - JOUR A1 - Zänker, Steffen A1 - Scholz, G. A1 - Marquardt, Julien A1 - Emmerling, Franziska T1 - Structural changes in Ba-compounds of different hardness induced by high-energy ball milling – evidenced by 137Ba NMR and X-ray powder diffraction N2 - Changes in the global bulk and local structures, of three different barium compounds (BaZrO3, BaF2, and BaFCl),were induced by mechanical milling and followed using X-ray powder diffraction (PXRD), subsequent microstructure analysis, and 137Ba solid state NMR spectroscopy. Harder materials like BaZrO3 experience significantly higher structural changes upon milling than softer materials like BaF2. Moreover, soft materials with layered structures, like BaFCl, show a pronounced structural change during the milling process. By combining PXRD and solid state NMR, detailed information on the changes to the global and local structures were obtained, which are of interest for mechanochemical synthesis, mechanically treated catalysts or ionic conductors. KW - Mechanochemistry KW - X-ray diffraction KW - Solid state NMR PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-547397 SN - 0044-2313 VL - 648 IS - 10 SP - 1 EP - 8 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54739 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martins, Ines A1 - Al-Sabbagh, Dominik A1 - Bentrup, U. A1 - Marquardt, Julien A1 - Schmid, Thomas A1 - Scoppola, E. A1 - Kraus, Werner A1 - Stawski, Tomasz A1 - de Oliveira Guilherme Buzanich, Ana A1 - Yusenko, Kirill A1 - Weidner, Steffen A1 - Emmerling, Franziska T1 - Formation Mechanism of a Nano-Ring of Bismuth Cations and Mono-Lacunary Keggin-Type Phosphomolybdate N2 - A new hetero-bimetallic polyoxometalate (POM) nano-ring was synthesized in a one-pot procedure. The structure consists of tetrameric units containing four bismuth-substituted monolacunary Keggin anions including distorted [BiO8] cubes. The nano-ring is formed via self-assembly from metal precursors in aqueous acidic medium. The compound (NH4)16[(BiPMo11O39)4] ⋅ 22 H2O; (P4Bi4Mo44) was characterized by single-crystal X-ray diffraction, extended X-ray absorption fine structure spectroscopy (EXAFS), Raman spectroscopy, matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF), and thermogravimetry/differential scanning calorimetry mass spectrometry (TG-DSC-MS). The formation of the nano-ring in solution was studied by time-resolved in situ small- and wide-angle X-ray scattering (SAXS/WAXS) and in situ EXAFS measurements at the Mo−K and the Bi−L3 edge indicating a two-step process consisting of condensation of Mo-anions and formation of Bi−Mo-units followed by a rapid self-assembly to yield the final tetrameric ring structure. KW - Bismuth KW - In situ EXAFS KW - In situ SAXS/WAXS KW - Lacunary Keggin ion KW - Polyoxometalates KW - Self-assembly PY - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-546823 SN - 0947-6539 VL - 28 IS - 27 SP - 1 EP - 7 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beyer, Sebastian A1 - Schürmann, Robin A1 - Feldmann, Ines A1 - Blocki, A. A1 - Bald, Ilko A1 - Schneider, Rudolf A1 - Emmerling, Franziska T1 - Maintaining Stable Zeolitic Imidazolate Framework (ZIF) Templates during Polyelectrolyte Multilayer Coating N2 - Equipping ZIF particles with a polyelectrolyte membrane provides functional groups at their interface, enabling further conjugations necessary for applications such as targeted drug delivery. Previous approaches to coat ZIF particles with polyelectrolytes led to surface corrosion of the template material. This work overcomes previous limitations by performing a Layer-by-Layer (LbL) polyelectrolyte coating onto ZIF-8 and ZIF-67 particles in nonaqueous environment. Using the 2-methylimidazolium salt of polystyrensulfonic acid instead of the acid itself and polyethyleneimine in methanol led to intact ZIF particles after polyelectrolyte coating. This was verified by electron microscopy. Further, zetapotential and atomic force microscopy measurements confirmed a continuous polyelectrolyte multilayer built up. The here reported adaption to the well-studied (LbL) polyelectrolyte selfassembly process provides a facile method to equip ZIF particles with a nanometer thin polyelectrolyte multilayer membrane. KW - Zeolithe KW - Molecular Organic Frameworks KW - MOF KW - ZIF KW - Layer-by-Layer KW - Beschichtung KW - Polyelektrolyt PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-447729 SN - 2215-0382 VL - 22 SP - 14 EP - 17 PB - Elsevier B.V. CY - Amsterdam, NL AN - OPUS4-44772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haferkamp, Sebastian A1 - Paul, Andrea A1 - Michalchuk, Adam A1 - Emmerling, Franziska T1 - Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation N2 - The transformation of a base-catalyzed, mechano-assisted Knoevenagel condensation of mono-fluorinated benzaldehyde derivatives (p-, m-, o-benzaldehyde) with malonodinitrile was investigated in situ and in real time. Upon milling, the para-substituted product was found to crystallize initially into two different polymorphic forms, depending on the quantity of catalyst used. For low catalyst concentrations, a mechanically metastable phase (monoclinic) was initially formed, converting to the mechanically stable phase (triclinic) upon further grinding. Instead, higher catalyst concentrations crystallize directly as the triclinic product. Inclusion of catalyst in the final product, as evidenced by mass spectrometric analysis, suggests this complex polymorphic pathway may be due to seeding effects. Multivariate analysis for the in situ Raman spectra supports this complex formation pathway, and offers a new approach to monitoring multi-phase reactions during ball milling. KW - Ball milling KW - C-C coupling KW - In situ KW - Mechanochemistry KW - Multivariate data analysis PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-481872 SN - 1860-5397 VL - 15 SP - 1141 EP - 1148 PB - Beilstein Insitut CY - Frankfurt am Main AN - OPUS4-48187 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Radunz, Sebastian A1 - Kraus, Werner A1 - Bischoff, F. A. A1 - Emmerling, Franziska A1 - Resch-Genger, Ute A1 - Tschiche, Harald T1 - Temperature- and Structure-Dependent Optical Properties and Photophysics of BODIPY Dyes N2 - We report on the temperature- and structural-dependent optical properties and photophysics of a set of boron dipyrromethene (BODIPY) dyes with different substitution patterns of their meso-aryl subunit. Single-crystal Xray diffraction analysis of the compounds enabled a classification of the dyes into a sterically hindered and a unhindered group. The steric hindrance refers to a blocked rotational motion of the aryl subunit around the bond connecting this moiety to the meso-position of the BODIPY core. The energy barriers related to this rotation were simulated by DFT calculations. As follows from the relatively low rotational barrier calculated to about 17 kcal/mol, a free rotation is only possible for sterically unhindered compounds. Rotational barriers of more than 40 kcal/mol determined for the sterically hindered compounds suggest an effective freezing of the rotational motion in These molecules. With the aid of temperature-dependent spectroscopic measurements, we could show that the ability to rotate directly affects the optical properties of our set of BODIPY dyes. This accounts for the strong temperature dependence of the fluorescence of the sterically unhindered compounds which show a drastic decrease in fluorescence quantum yield and a significant shortening in fluorescence lifetime upon heating. The optical properties of the sterically hindered compounds, however, are barely affected by temperature. Our results suggest a nonradiative deactivation of the first excited singlet state of the sterically unhindered compounds caused by a conical intersection of the potential energy surfaces of the Ground and first excited state which is accessible by rotation of the meso-subunit. This is in good agreement with previously reported deactivation mechanisms. In addition, our results suggest the presence of a second nonradiative depopulation pathway of the first excited singlet state which is particularly relevant for the sterically hindered compounds. KW - Fluorescence KW - Sensor KW - Switch KW - pH KW - BODIPY KW - Dye KW - Probe KW - Synthesis KW - Photophysics KW - Mechanism PY - 2020 U6 - https://doi.org/10.1021/acs.jpca.9b11859 SN - 1089-5639 VL - 124 IS - 9 SP - 1787 EP - 1797 PB - American Chemical Society AN - OPUS4-50639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chapartegui-Arias, Ander A1 - Villajos Collado, José Antonio A1 - Myxa, Anett A1 - Beyer, Sebastian A1 - Falkenhagen, Jana A1 - Schneider, Rudolf A1 - Emmerling, Franziska T1 - Covalently Fluorophore-Functionalized ZIF‑8 Colloidal Particles as a Sensing Platform for Endocrine-Disrupting Chemicals Such as Phthalates Plasticizers N2 - We present the optical sensing of phthalate Esters (PAEs), a group of endocrine-disrupting chemicals. The sensing takes place as changes in the fluorescence emission intensity of aminopyrene covalently bound to the organic ligands of the metal−organic framework compound ZIF-8. In the presence of PAEs, a quenching of the fluorescence emission is observed. We evaluated strategies to engineer colloidal size distribution of the sensing particles to optimize the sensory response to PAEs. A thorough characterization of the modified ZIF-8 nanoparticles included powder X-ray diffractometry, transmission electron microscopy, high-performance liquid chromatography, and photophysical characterization. The presented capability of the fluorophore-functionalized ZIF-8 to sense PAEs complements established methods such as chromatography-based procedures, which cannot be used on-site and paves the way for future developments such as hand-held quick sensing devices. KW - Sensing KW - MOF PY - 2019 U6 - https://doi.org/10.1021/acsomega.9b01051 VL - 4 IS - 17 SP - 17090 EP - 17097 PB - ACS AN - OPUS4-49562 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grunert, B. A1 - Saatz, Jessica A1 - Hoffmann, Katrin A1 - Appler, F. A1 - Lubjuhn, Dominik A1 - Jakubowski, Norbert A1 - Resch-Genger, Ute A1 - Emmerling, Franziska A1 - Briel, A. T1 - Multifunctional rare-earth element nanocrystals for cell labeling and multimodal imaging N2 - In this work, we describe a simple solvothermal route for the synthesis of Eu3+-doped gadolinium orthovanadate nanocrystals (Eu:GdVO4−PAA) functionalized with poly(acrylic)acid (PAA), that are applicable as cell labeling probes for multimodal cellular imaging. The Eu3+ doping of the vanadate matrix provides optical functionality, due to red photoluminescence after illumination with UV light. The Gd3+ ions of the nanocrystals reduce the T1 relaxation time of surrounding water protons, allowing these nanocrystals to act as a positive MRI contrast agent with a r1 relaxivity of 1.97 mM−1 s−1. Low background levels of Eu3+, Gd3+, and V5+ in biological systems make them an excellent label for elemental microscopy by Laser Ablation (LA)-ICP-MS. Synthesis resulted in polycrystalline nanocrystals with a hydrodynamic diameter of 55 nm and a crystal size of 36.7 nm, which were further characterized by X-ray diffraction (XRD), photoluminescence spectroscopy (PL) and transmission electron microscopy (TEM). The multifunctional nanocrystals were subsequently used for intracellular labeling of both human adipose-derived stem cells (MSCs) and A549 (adenocarcinomic human alveolar basal epithelial) cells. KW - Bioimaging KW - Nanoparticle KW - Multimodal KW - Lanthanide PY - 2018 U6 - https://doi.org/10.1021/acsbiomaterials.8b00495 SN - 2373-9878 VL - 4 IS - 10 SP - 3578 EP - 3587 PB - ACS Publications CY - Washington, USA AN - OPUS4-46244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karafiludis, Stephanos A1 - Kochovski, Z. A1 - Scoppola, E. A1 - Retzmann, Anika A1 - Hodoroaba, Vasile-Dan A1 - ten Elshof, J. E. A1 - Emmerling, Franziska A1 - Stawski, Tomasz Maciej T1 - Nonclassical Crystallization Pathway of Transition Metal Phosphate Compounds N2 - Here, we elucidate nonclassical multistep crystallization pathways of transition metal phosphates from aqueous solutions. We followed precipitation processes of M-struvites, NH4MPO4·6H2O, and M-phosphate octahydrates, M3(PO4)2·8H2O, where M = Ni, Co, or NixCo1–x, by using in situ scattering and spectroscopy-based techniques, supported by elemental mass spectrometry analyses and advanced electron microscopy. Ni and Co phosphates crystallize via intermediate colloidal amorphous nanophases, which change their complex structures while agglomerating, condensing, and densifying throughout the extended reaction times. We reconstructed the three-dimensional morphology of these precursors by employing cryo-electron tomography (cryo-ET). We found that the complex interplay between metastable amorphous colloids and protocrystalline units determines the reaction pathways. Ultimately, the same crystalline structure, such as struvite, is formed. However, the multistep process stages vary in complexity and can last from a few minutes to several hours depending on the selected transition metal(s), their concentration, and the Ni/Co ratio. KW - Non-classical crystallization theory KW - Transition metals KW - Phosphates KW - Amorphous phases KW - Intermediate phases PY - 2023 U6 - https://doi.org/10.1021/acs.chemmater.3c02346 SN - 1520-5002 VL - 35 IS - 24 SP - 10645 EP - 10657 PB - American Chemical Society (ACS) CY - Washington D.C. AN - OPUS4-59135 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bornemann-Pfeiffer, Martin A1 - Wolf, Jakob A1 - Meyer, Klas A1 - Kern, S. A1 - Angelone, D. A1 - Leonov, A. A1 - Cronin, L. A1 - Emmerling, Franziska T1 - Standardization and control of Grignard reactions in a universal chemical synthesis machine using online NMR T1 - Standardisierung und Kontrolle von Grignard-Reaktionen mittels Online-NMR in einer universellen chemischen Syntheseplattform N2 - A big problem with the chemistry literature is that it is not standardized with respect to precise operational parameters, and real time corrections are hard to make without expert knowledge. This lack of context means difficult reproducibility because many steps are ambiguous, and hence depend on tacit knowledge. Here we present the integration of online NMR into an automated chemical synthesis machine (CSM aka. “Chemputer” which is capable of small-molecule synthesis using a universal programming language) to allow automated analysis and adjustment of reactions on the fly. The system was validated and benchmarked by using Grignard reactions which were chosen due to their importance in synthesis. The system was monitored in real time using online-NMR, and spectra were measured continuously during the reactions. This shows that the synthesis being done in the Chemputer can be dynamically controlled in response to feedback optimizing the reaction conditions according to the user requirements. N2 - Ein Problem der chemischen Literatur ist die fehlende Standardisierung bezüglich genauer Bedingungen, auch Echtzeit-Korrekturen sind ohne Expertenwissen nur schwer möglich. Dieser Mangel an Details erschwert experimentelle Reproduzierbarkeit, da Schritte oft mehrdeutig sind und daher von implizitem Wissen abhängen. Hier präsentieren wir die Integration von Online-NMR Spektroskopie in eine automatisierte chemische Syntheseplattform (CSM aka. “Chemputer”, unter Verwendung einer universellen Programmiersprache zur Synthese kleiner Moleküle fähig), um eine automatisierte Analyse und Anpassung von Reaktionen im laufenden Betrieb zu ermöglichen. Das System wurde anhand von Grignard-Reaktionen, die aufgrund ihrer Bedeutung für die Synthese ausgewählt wurden, validiert und einem Härtetest unterzogen. Synthesen wurden in Echtzeit mit Online-NMR überwacht, und die Spektren wurden während der Reaktionen kontinuierlich aufgenommen und analysiert. Dies zeigt, dass der Chemputer dynamisch mittels einer Regelung kontrolliert werden kann, um die Reaktionsbedingungen entsprechend den Anforderungen des Benutzers zu optimieren. KW - Grignard reaction KW - NMR spectroscopy KW - Process analytical technology KW - Process control KW - Grignard-Reaktion KW - NMR-Spektroskopie KW - Prozessanalytik KW - Prozesskontrolle PY - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-531260 SN - 1521-3773 SN - 1433-7851 N1 - Bibliografische Angaben für die deutsche Version: Angewandte Chemie 2021, Jg. 133, S. 1–7, ISSN 0044-8249, ISSN 1521-3757, https://doi.org/10.1002/ange.202106323 - Bibliographic information for the German version: Angewandte Chemie 2021, vol. 133, p. 1–7, ISSN 0044-8249, ISSN 1521-3757, https://doi.org/10.1002/ange.202106323 VL - 60 IS - 43 SP - 1 EP - 6 PB - Wiley-VCH CY - Weinheim AN - OPUS4-53126 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gugin, Nikita A1 - Villajos Collado, José Antonio A1 - Dautain, O. A1 - Maiwald, Michael A1 - Emmerling, Franziska T1 - Optimizing the Green Synthesis of ZIF-8 by Reactive Extrusion Using In Situ Raman Spectroscopy N2 - We report the scale-up of a batch solid synthesis of zeolitic imidazolate framework-8 (ZIF-8) for reactive extrusion. The crystalline product forms in the extruder directly under the mixture of solid 2-methylimidazole and basic zinc carbonate in the presence of a catalytic amount of liquid. The process parameters such as temperature, liquid type, feeding rate, and linker excess were optimized using the setup specifically designed for in situ Raman spectroscopy. Highly crystalline ZIF-8 with a Brunauer–Emmett–Teller (BET) surface area of 1816 m2 g–1 was quantitatively prepared at mild temperature using a catalytic amount of ethanol and a small excess of the linker. Finally, we developed a simple and comprehensive approach to evaluating the environmental friendliness and scalability of metal–organic framework (MOF) syntheses in view of their large-scale production. KW - Mechanochemistry KW - In situ Raman KW - Large-scale processing KW - Metal−organic frameworks KW - Twin-screw extrusion (TSE) PY - 2023 U6 - https://doi.org/10.1021/acssuschemeng.2c07509 SN - 2168-0485 VL - 11 IS - 13 SP - 5175 EP - 5183 PB - ACS Publications AN - OPUS4-57366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -