TY - JOUR A1 - Mullan, Thomas A1 - Maschio, Lorenzo A1 - Saalfrank, Peter A1 - Usvyat, Denis T1 - Reaction barriers on non-conducting surfaces beyond periodic local MP2 BT - Diffusion of hydrogen on alpha-Al2O3 (0001) as a test case JF - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr N2 - The quest for "chemical accuracy" is becoming more and more demanded in the field of structure and kinetics of molecules at solid surfaces. In this paper, as an example, we focus on the barrier for hydrogen diffusion on a alpha-Al2O3 (0001) surface, aiming for a couple cluster singles, doubles, and perturbative triples [CCSD(T)]-level benchmark. We employ the density functional theory (DFT) optimized minimum and transition state structures reported by Heiden, Usvyat, and Saalfrank [J. Phys. Chem. C 123, 6675 (2019)]. The barrier is first evaluated at the periodic Hartree-Fock and local Moller-Plesset second-order perturbation (MP2) level of theory. The possible sources of errors are then analyzed, which includes basis set incompleteness error, frozen core, density fitting, local approximation errors, as well as the MP2 method error. Using periodic and embedded fragment models, corrections to these errors are evaluated. In particular, two corrections are found to be non-negligible (both from the chemical accuracy perspective and at the scale of the barrier value of 0.72 eV): the correction to the frozen core-approximation of 0.06 eV and the CCSD(T) correction of 0.07 eV. Our correlated wave function results are compared to barriers obtained from DFT. Among the tested DFT functionals, the best performing for this barrier is B3LYP-D3. Y1 - 2022 U6 - https://doi.org/10.1063/5.0082805 SN - 0021-9606 SN - 1089-7690 VL - 156 IS - 7 PB - AIP Publishing CY - Melville ER - TY - JOUR A1 - Yue, Yanhua A1 - Melani, Giacomo A1 - Kirsch, Harald A1 - Paarmann, Alexander A1 - Saalfrank, Peter A1 - Campen, Richard Kramer A1 - Tong, Yujin T1 - Structure and Reactivity of a-Al2O3(0001) Surfaces: How Do Al-I and Gibbsite-like Terminations Interconvert? JF - The journal of physical chemistry / publ. weekly by the American Chemical Society. C, Energy, materials, and catalysis N2 - The alpha-Al2O3(0001) surface has been extensively studied because of its significance in both fundamental research and application. Prior work suggests that in ultra-high-vacuum (UHV), in the absence of water, the so-called Al-I termination is thermodynamically favored, while in ambient, in contact with liquid water, a Gibbsite-like layer is created. While the view of the alpha- Al2O3(0001)/H2O(l) interface appears relatively clear in theory, experimental characterization of this system has resulted in estimates of surface acidity, i.e., isoelectric points, that differ by 4 pH units and surface structure that in some reports has non-hydrogen-bonded surface aluminol (Al-OH) groups and in others does not. In this study, we employed vibrational sum frequency spectroscopy (VSFS) and density functional theory (DFT) simulation to study the surface phonon modes of the differently terminated alpha-Al2O3(0001) surfaces in both UHV and ambient. We find that, on either water dosing of the Al-I in UHV or heat-induced dehydroxylation of the Gibbsite-like in ambient, the surfaces do not interconvert. This observation offers a new explanation for disagreements in prior work on the alpha-Al2O3(0001)/liquid water interface -different preparation methods may create surfaces that do not interconvert-and shows that the surface phonon spectral response offers a novel probe of interfacial hydrogen bonding structure. Y1 - 2022 U6 - https://doi.org/10.1021/acs.jpcc.2c03743 SN - 1932-7447 SN - 1932-7455 VL - 126 IS - 31 SP - 13467 EP - 13476 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Tarazona Lizcano, Natalia Andrea A1 - Machatschek, Rainhard Gabriel A1 - Balcucho, Jennifer A1 - Castro-Mayorga, Jinneth Lorena A1 - Saldarriaga, Juan Francisco A1 - Lendlein, Andreas T1 - Opportunities and challenges for integrating the development of sustainable polymer materials within an international circular (bio)economy concept JF - MRS energy & sustainability : science & technology & socio-economics & policy N2 - The production and consumption of commodity polymers have been an indispensable part of the development of our modern society. Owing to their adjustable properties and variety of functions, polymer-based materials will continue playing important roles in achieving the Sustainable Development Goals (SDG)s, defined by the United Nations, in key areas such as healthcare, transport, food preservation, construction, electronics, and water management. Considering the serious environmental crisis, generated by increasing consumption of plastics, leading-edge polymers need to incorporate two types of functions: Those that directly arise from the demands of the application (e.g. selective gas and liquid permeation, actuation or charge transport) and those that enable minimization of environmental harm, e.g., through prolongation of the functional lifetime, minimization of material usage, or through predictable disintegration into non-toxic fragments. Here, we give examples of how the incorporation of a thoughtful combination of properties/functions can enhance the sustainability of plastics ranging from material design to waste management. We focus on tools to measure and reduce the negative impacts of plastics on the environment throughout their life cycle, the use of renewable sources for their synthesis, the design of biodegradable and/or recyclable materials, and the use of biotechnological strategies for enzymatic recycling of plastics that fits into a circular bioeconomy. Finally, we discuss future applications for sustainable plastics with the aim to achieve the SDGs through international cooperation.
Leading-edge polymer-based materials for consumer and advanced applications are necessary to achieve sustainable development at a global scale. It is essential to understand how sustainability can be incorporated in these materials via green chemistry, the integration of bio-based building blocks from biorefineries, circular bioeconomy strategies, and combined smart and functional capabilities. KW - biomaterial KW - degradable KW - functional KW - life cycle assessment KW - renewable KW - sustainability Y1 - 2022 U6 - https://doi.org/10.1557/s43581-021-00015-7 SN - 2329-2229 SN - 2329-2237 VL - 9 IS - 1 SP - 28 EP - 34 PB - Springer Nature CY - London ER - TY - JOUR A1 - Halbrügge, Lena A1 - Banerji, Amitabh A1 - Meerholz, Klaus T1 - Hallo Zukunft! BT - gedruckte Elektronik als Hands-on-Experiment für die Lehre in den Naturwissenschaften an (Hoch-)Schulen JF - Chemie konkret : CHEMKON ; Forum für Unterricht und Didaktik N2 - Gedruckte Elektronik ist nicht nur ein aufstrebendes Forschungsfeld, sie wird in naher Zukunft auch eine wesentliche Rolle in unserem Alltag spielen. Gedruckte, elektronische Bauteile können sehr dünn und flexibel sein und somit vielfältig eingesetzt werden. Für die Implementation in der (Hoch-)Schule haben die Autoren eine flexible, lichtemittierende Folie entwickelt, die mit einfachen Materialien und Methoden manuell gedruckt werden kann. N2 - Printed electronics is an emerging research field and is going to play a vital role in our everyday-life in the near future. Printed electronic devices can be very thin and flexible, which makes them feasible for various applications. For the implementation in High Schools and Universities the authors developed a flexible, light emitting foil, which can be printed manually using simple materials and methods. T2 - Hello future! Printed electronics as a hands-on-experiment for teaching science in high schools and universities KW - curriculum innovation KW - experiment KW - electroluminescence KW - semiconductor KW - curriculare Innovation KW - Experiment KW - Elektrolumineszenz KW - Halbleiter Y1 - 2022 U6 - https://doi.org/10.1002/ckon.202200030 SN - 0944-5846 SN - 1521-3730 VL - 29 IS - 51 SP - 355 EP - 361 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Stefancu, Andrei A1 - Nan, Lin A1 - Zhu, Li A1 - Chis, Vasile A1 - Bald, Ilko A1 - Liu, Min A1 - Leopold, Nicolae A1 - Maier, Stefan A. A1 - Cortes, Emiliano T1 - Controlling plasmonic chemistry pathways through specific ion effects JF - Advanced optical materials N2 - Plasmon-driven dehalogenation of brominated purines has been recently explored as a model system to understand fundamental aspects of plasmon-assisted chemical reactions. Here, it is shown that divalent Ca2+ ions strongly bridge the adsorption of bromoadenine (Br-Ade) to Ag surfaces. Such ion-mediated binding increases the molecule's adsorption energy leading to an overlap of the metal energy states and the molecular states, enabling the chemical interface damping (CID) of the plasmon modes of the Ag nanostructures (i.e., direct electron transfer from the metal to Br-Ade). Consequently, the conversion of Br-Ade to adenine almost doubles following the addition of Ca2+. These experimental results, supported by theoretical calculations of the local density of states of the Ag/Br-Ade complex, indicate a change of the charge transfer pathway driving the dehalogenation reaction, from Landau damping (in the lack of Ca2+ ions) to CID (after the addition of Ca2+). The results show that the surface dynamics of chemical species (including water molecules) play an essential role in charge transfer at plasmonic interfaces and cannot be ignored. It is envisioned that these results will help in designing more efficient nanoreactors, harnessing the full potential of plasmon-assisted chemistry. KW - chemical interface damping KW - Hofmeister effect KW - hydration layer KW - plasmonic chemistry KW - specific ion effects KW - surface-enhanced Raman scattering Y1 - 2022 U6 - https://doi.org/10.1002/adom.202200397 SN - 2195-1071 VL - 10 IS - 14 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Schürmann, Robin A1 - Titov, Evgenii A1 - Ebel, Kenny A1 - Kogikoski Junior, Sergio A1 - Mostafa, Amr A1 - Saalfrank, Peter A1 - Milosavljević, Aleksandar R. A1 - Bald, Ilko T1 - The electronic structure of the metal-organic interface of isolated ligand coated gold nanoparticles JF - Nanoscale Advances N2 - Light induced electron transfer reactions of molecules on the surface of noble metal nanoparticles (NPs) depend significantly on the electronic properties of the metal-organic interface. Hybridized metal-molecule states and dipoles at the interface alter the work function and facilitate or hinder electron transfer between the NPs and ligand. X-ray photoelectron spectroscopy (XPS) measurements of isolated AuNPs coated with thiolated ligands in a vacuum have been performed as a function of photon energy, and the depth dependent information of the metal-organic interface has been obtained. The role of surface dipoles in the XPS measurements of isolated ligand coated NPs is discussed and the binding energy of the Au 4f states is shifted by around 0.8 eV in the outer atomic layers of 4-nitrothiophenol coated AuNPs, facilitating electron transport towards the molecules. Moreover, the influence of the interface dipole depends significantly on the adsorbed ligand molecules. The present study paves the way towards the engineering of the electronic properties of the nanoparticle surface, which is of utmost importance for the application of plasmonic nanoparticles in the fields of heterogeneous catalysis and solar energy conversion. Y1 - 2022 U6 - https://doi.org/10.1039/d1na00737h SN - 2516-0230 VL - 4 IS - 6 SP - 1599 EP - 1607 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Michaelis, Vivien A1 - Aengenheister, Leonie A1 - Tuchtenhagen, Max A1 - Rinklebe, Jörg A1 - Ebert, Franziska A1 - Schwerdtle, Tanja A1 - Buerki-Thurnherr, Tina A1 - Bornhorst, Julia T1 - Differences and interactions in placental manganese and iron transfer across an in vitro model of human villous trophoblasts JF - International journal of molecular sciences N2 - Manganese (Mn) as well as iron (Fe) are essential trace elements (TE) important for the maintenance of physiological functions including fetal development. However, in the case of Mn, evidence suggests that excess levels of intrauterine Mn are associated with adverse pregnancy outcomes. Although Mn is known to cross the placenta, the fundamentals of Mn transfer kinetics and mechanisms are largely unknown. Moreover, exposure to combinations of TEs should be considered in mechanistic transfer studies, in particular for TEs expected to share similar transfer pathways. Here, we performed a mechanistic in vitro study on the placental transfer of Mn across a BeWo b30 trophoblast layer. Our data revealed distinct differences in the placental transfer of Mn and Fe. While placental permeability to Fe showed a clear inverse dose-dependency, Mn transfer was largely independent of the applied doses. Concurrent exposure of Mn and Fe revealed transfer interactions of Fe and Mn, indicating that they share common transfer mechanisms. In general, mRNA and protein expression of discussed transporters like DMT1, TfR, or FPN were only marginally altered in BeWo cells despite the different exposure scenarios highlighting that Mn transfer across the trophoblast layer likely involves a combination of active and passive transport processes. KW - manganese KW - iron KW - placental transfer KW - TE interactions KW - BeWo b30 KW - trophoblasts Y1 - 2022 U6 - https://doi.org/10.3390/ijms23063296 SN - 1422-0067 VL - 23 IS - 6 PB - MDPI CY - Basel ER - TY - JOUR A1 - Crovetto, Andrea A1 - Kojda, Danny A1 - Yi, Feng A1 - Heinselman, Karen N. A1 - LaVan, David A. A1 - Habicht, Klaus A1 - Unold, Thomas A1 - Zakutayev, Andriy T1 - Crystallize It before It diffuses BT - kinetic stabilization of thin-film phosphorus-rich semiconductor CuP2 JF - Journal of the american chemical society N2 - Numerous phosphorus-rich metal phosphides containing both P-P bonds and metal-P bonds are known from the solid-state chemistry literature. A method to grow these materials in thin-film form would be desirable, as thin films are required in many applications and they are an ideal platform for high-throughput studies. In addition, the high density and smooth surfaces achievable in thin films are a significant advantage for characterization of transport and optical properties. Despite these benefits, there is hardly any published work on even the simplest binary phosphorus-rich phosphide films. Here, we demonstrate growth of single-phase CuP2 films by a two-step process involving reactive sputtering of amorphous CuP2+x and rapid annealing in an inert atmosphere. At the crystallization temperature, CuP2 is thermodynamically unstable with respect to Cu3P and P-4. However, CuP2 can be stabilized if the amorphous precursors are mixed on the atomic scale and are sufficiently close to the desired composition (neither too P poor nor too P rich). Fast formation of polycrystalline CuP2, combined with a short annealing time, makes it possible to bypass the diffusion processes responsible for decomposition. We find that thin-film CuP2 is a 1.5 eV band gap semiconductor with interesting properties, such as a high optical absorption coefficient (above 10(5) cm(-1)), low thermal conductivity (1.1 W/(K m)), and composition-insensitive electrical conductivity (around 1 S/cm). We anticipate that our processing route can be extended to other phosphorus-rich phosphides that are still awaiting thin-film synthesis and will lead to a more complete understanding of these materials and of their potential applications. Y1 - 2022 U6 - https://doi.org/10.1021/jacs.2c04868 SN - 0002-7863 SN - 1520-5126 VL - 144 IS - 29 SP - 13334 EP - 13343 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Lepre, Enrico A1 - Heske, Julian A1 - Nowakowski, Michal A1 - Scoppola, Ernesto A1 - Zizak, Ivo A1 - Heil, Tobias A1 - Kühne, Thomas D. A1 - Antonietti, Markus A1 - Lopez-Salas, Nieves A1 - Albero, Josep T1 - Ni-based electrocatalysts for unconventional CO2 reduction reaction to formic acid JF - Nano energy N2 - Electrochemical reduction stands as an alternative to revalorize CO2. Among the different alternatives, Ni single atoms supported on carbonaceous materials are an appealing catalytic solution due to the low cost and versatility of the support and the optimal usage of Ni and its predicted selectivity and efficiency (ca. 100% towards CO). Herein, we have used noble carbonaceous support derived from cytosine to load Ni subnanometric sites. The large heteroatom content of the support allows the stabilization of up to 11 wt% of Ni without the formation of nanoparticles through a simple impregnation plus calcination approach, where nickel promotes the stabilization of C3NOx frameworks and the oxidative support promotes a high oxidation state of nickel. EXAFS analysis points at nickel single atoms or subnanometric clusters coordinated by oxygen in the material surface. Unlike the wellknown N-coordinated Ni single sites selectivity towards CO2 reduction, O-coordinated-Ni single sites (ca. 7 wt% of Ni) reduced CO2 to CO, but subnanometric clusters (11 wt% of Ni) foster the unprecedented formation of HCOOH with 27% Faradaic efficiency at - 1.4 V. Larger Ni amounts ended up on the formation of NiO nanoparticles and almost 100% selectivity towards hydrogen evolution. KW - CO 2 reduction reaction KW - Noble carbon KW - Ni-O4 electrocatalysts KW - Formic acid Y1 - 2022 U6 - https://doi.org/10.1016/j.nanoen.2022.107191 SN - 2211-2855 SN - 2211-3282 VL - 97 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mei, Shilin A1 - Siebert, Andreas A1 - Xu, Yaolin A1 - Quan, Ting A1 - Garcia-Diez, Raul A1 - Bär, Marcus A1 - Härtel, Paul A1 - Abendroth, Thomas A1 - Dörfler, Susanne A1 - Kaskel, Stefan A1 - Lu, Yan T1 - Large-Scale Synthesis of Nanostructured Carbon-Ti4O7 Hollow Particles as Efficient Sulfur Host Materials for Multilayer Lithium-Sulfur Pouch Cells JF - Batteries & supercaps N2 - Applications of advanced cathode materials with well-designed chemical components and/or optimized nanostructures promoting the sulfur redox kinetics and suppressing the shuttle effect of polysulfides are highly valued. However, in the case of actual lithium-sulfur (Li-S) batteries under practical working conditions, one long-term obstacle still exists, which is mainly due to the difficulties in massive synthesis of such nanomaterials with low cost and ease of control on the nanostructure. Herein, we develop a facile synthesis of carbon coated Ti4O7 hollow nanoparticles (Ti4O7) using spherical polymer electrolyte brush as soft template, which is scalable via utilizing a minipilot reactor. The C Ti4O7 hollow nanoparticles provide strong chemical adsorption to polysulfides through the large polar surface and additional physical confinement by rich micro- & mesopores and have successfully been employed as an efficient sulfur host for multilayer pouch cells. Besides, the sluggish kinetics of the sulfur and lithium sulfide redox mechanism can be improved by the highly conductive Ti4O7 via catalyzation of the conversion of polysulfides. Consequently, the C-Ti4O7 based pouch cell endows a high discharge capacity of 1003 mAhg(-1) at 0.05 C, a high-capacity retention of 83.7% after 100 cycles at 0.1 C, and a high Coulombic efficiency of 97.5% at the 100th cycle. This work proposes an effective approach to transfer the synthesis of hollow Ti4O7 nanoparticles from lab- to large-scale production, paving the way to explore a wide range of advanced nanomaterials for multilayer Li-S pouch cells. KW - lithium-sulfur batteries KW - pouch cell KW - spherical polyelectrolyte brushes (SPB) KW - Ti4O7 Y1 - 2022 U6 - https://doi.org/10.1002/batt.202100398 SN - 2566-6223 VL - 5 IS - 6 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Tung, Wing Tai A1 - Maring, Janita A. A1 - Xu, Xun A1 - Liu, Yue A1 - Becker, Matthias A1 - Somesh, Dipthi Bachamanda A1 - Klose, Kristin A1 - Wang, Weiwei A1 - Sun, Xianlei A1 - Ullah, Imran A1 - Kratz, Karl A1 - Neffe, Axel T. A1 - Stamm, Christof A1 - Ma, Nan A1 - Lendlein, Andreas T1 - In vivo performance of a cell and factor free multifunctional fiber mesh modulating postinfarct myocardial remodeling JF - Advanced Functional Materials N2 - Guidance of postinfarct myocardial remodeling processes by an epicardial patch system may alleviate the consequences of ischemic heart disease. As macrophages are highly relevant in balancing immune response and regenerative processes their suitable instruction would ensure therapeutic success. A polymeric mesh capable of attracting and instructing monocytes by purely physical cues and accelerating implant degradation at the cell/implant interface is designed. In a murine model for myocardial infarction the meshes are compared to those either coated with extracellular matrix or loaded with induced cardiomyocyte progenitor cells. All implants promote macrophage infiltration and polarization in the epicardium, which is verified by in vitro experiments. 6 weeks post-MI, especially the implantation of the mesh attenuates left ventricular adverse remodeling processes as shown by reduced infarct size (14.7% vs 28-32%) and increased wall thickness (854 mu m vs 400-600 mu m), enhanced angiogenesis/arteriogenesis (more than 50% increase compared to controls and other groups), and improved heart function (ejection fraction = 36.8% compared to 12.7-31.3%). Upscaling as well as process controls is comprehensively considered in the presented mesh fabrication scheme to warrant further progression from bench to bedside. KW - bioinstructive materials KW - cardiac regeneration KW - function by structure; KW - modulation of in vivo regeneration KW - multifunctional biomaterials Y1 - 2022 U6 - https://doi.org/10.1002/adfm.202110179 SN - 1616-301X SN - 1616-3028 VL - 32 IS - 31 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Ning, Jiaoyi A1 - Yu, Hongtao A1 - Mei, Shilin A1 - Schütze, Yannik A1 - Risse, Sebastian A1 - Kardjilov, Nikolay A1 - Hilger, André A1 - Manke, Ingo A1 - Bande, Annika A1 - Ruiz, Victor G. A1 - Dzubiella, Joachim A1 - Meng, Hong A1 - Lu, Yan T1 - Constructing binder- and carbon additive-free organosulfur cathodes based on conducting thiol-polymers through electropolymerization for lithium-sulfur batteries JF - ChemSusChem N2 - Herein, the concept of constructing binder- and carbon additive-free organosulfur cathode was proved based on thiol-containing conducting polymer poly(4-(thiophene-3-yl) benzenethiol) (PTBT). The PTBT featured the polythiophene-structure main chain as a highly conducting framework and the benzenethiol side chain to copolymerize with sulfur and form a crosslinked organosulfur polymer (namely S/PTBT). Meanwhile, it could be in-situ deposited on the current collector by electro-polymerization, making it a binder-free and free-standing cathode for Li-S batteries. The S/PTBT cathode exhibited a reversible capacity of around 870 mAh g(-1) at 0.1 C and improved cycling performance compared to the physically mixed cathode (namely S&PTBT). This multifunction cathode eliminated the influence of the additives (carbon/binder), making it suitable to be applied as a model electrode for operando analysis. Operando X-ray imaging revealed the remarkable effect in the suppression of polysulfides shuttle via introducing covalent bonds, paving the way for the study of the intrinsic mechanisms in Li-S batteries. KW - electrochemistry KW - energy storage KW - lithium-sulfur batteries KW - operando KW - studies KW - organosulfur Y1 - 2022 U6 - https://doi.org/10.1002/cssc.202200434 SN - 1864-5631 SN - 1864-564X VL - 15 IS - 14 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Pham, Duong Tung A1 - Quan, Ting A1 - Mei, Shilin A1 - Lu, Yan T1 - Colloidal metal sulfide nanoparticles for high performance electrochemical energy storage systems JF - Current opinion in green and sustainable chemistry N2 - Transition metal sulfides have emerged as excellent replacement candidates of traditional insertion electrode materials based on their conversion or alloying mechanisms, facilitating high specific capacity and rate ability. However, parasitic reactions such as massive volume change during the discharge/ charge processes, intermediate polysulfide dissolution, and passivating solid electrolyte interface formation have led to poor cyclability, hindering their feasibility and applicability in energy storage systems. Colloidal metal sulfide nanoparticles, a special class that integrates the intrinsic chemical properties of metal sulfides and their specified structural features, have fairly enlarged their contribution due to the synergistic effect. This review highlights the latest synthetic approaches based on colloidal process. Their corresponding electrochemical outcomes will also be discussed, which are thoroughly updated along with their insight scientific standpoints. Y1 - 2022 U6 - https://doi.org/10.1016/j.cogsc.2022.100596 SN - 2452-2236 VL - 34 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Xie, Dongjiu A1 - Jouini, Oumeima A1 - Mei, Shilin A1 - Quan, Ting A1 - Xu, Yaolin A1 - Kochovski, Zdravko A1 - Lu, Yan T1 - Spherical polyelectrolyte brushes templated hollow C@MnO nanospheres as sulfur host materials for Li-S batteries JF - ChemNanoMat : Chemistry of Nanomaterials for Energy, Biology and More N2 - Li-S battery has been considered as the next-generation energy storage device, which still suffers from the shuttle effect of lithium polysulfides (LiPSs). In this work, mesoporous hollow carbon-coated MnO nanospheres (C@MnO) have been designed and synthesized using spherical polyelectrolyte brushes (SPB) as template, KMnO4 as MnO precursor, and polydopamine as carbon source to improve the electrochemical performance of Li-S battery. The hollow C@MnO nanospheres enable the combination of physical confinement and chemical adsorption of the LiPSs. The thin carbon coating layer can provide good electrical conductivity and additional physical confinement to polysulfides. Moreover, the encapsulated MnO inside the carbon shell exhibits strong chemical adsorption to polysulfides. The constructed C@MnO/S cathode shows the discharge capacity of 1026 mAh g(-1) at 0.1 C with 79% capacity retention after 80 cycles. The synthesized hollow C@MnO nanoparticles can work as highly efficient sulfur host materials, providing an effective solution to suppress the shuttle effect in Li-S battery. KW - hollow nanospheres KW - lithium-sulfur battery KW - manganese monoxide KW - sperical KW - polyelectrolyte brushes Y1 - 2022 U6 - https://doi.org/10.1002/cnma.202100455 SN - 2199-692X VL - 8 IS - 4 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Pessanha, Tatiana A1 - Paschoalino, Waldemir J. A1 - Deroco, Patricia B. A1 - Kogikoski Junior, Sergio A1 - Moraes, Ana C. M. de A1 - Carvalho Castro de Silva, Cecilia de A1 - Kubota, Lauro T. T1 - Interfacial capacitance of graphene oxide films electrodes BT - Fundamental studies on electrolytes interface aiming (bio)sensing applications JF - Electroanalysis : an internatinal journal devoted to electroanalysis, sensors and bioelectronic devices N2 - The understanding of bidimensional materials dynamics and its electrolyte interface equilibrium, such as graphene oxide (GO), is critical for the development of a capacitive biosensing platform. The interfacial capacitance (C-i) of graphene-based materials may be tuned by experimental conditions such as pH optimization and cation size playing key roles at the enhancement of their capacitive properties allowing their application as novel capacitive biosensors. Here we reported a systematic study of C-i of multilayer GO films in different aqueous electrolytes employing electrochemical impedance spectroscopy for the application in a capacitive detection system. We demonstrated that the presence of ionizable oxygen-containing functional groups within multilayer GO film favors the interactions and the accumulation of cations in the structure of the electrodes enhancing the GO C-i in aqueous solutions, where at pH 7.0 (the best condition) the C-i was 340 mu F mg(-1) at -0.01 V vs Ag/AgCl. We also established that the hydrated cation radius affects the mobility and interaction with GO functional groups and it plays a critical role in the Ci, as demonstrated in the presence of different cations Na+=640 mu F mg(-1), Li+=575 mu F mg(-1) and TMA(+)=477 mu F mg(-1). As a proof-of-concept, the capacitive behaviour of GO was explored as biosensing platform for standard streptavidin-biotin systems. For this system, the C-i varied linearly with the log of the concentration of the targeting analyte in the range from 10 pg mL(-1) to 100 ng mL(-1), showing the promising applicability of capacitive GO based sensors for label-free biosensing. KW - Interfacial capacitance KW - Graphene oxide KW - Functional groups KW - Electrochemical impedance KW - Graphene derivates Y1 - 2021 U6 - https://doi.org/10.1002/elan.202100220 SN - 1521-4109 SN - 1040-0397 VL - 34 IS - 4 SP - 692 EP - 700 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Xu, Yaolin A1 - Dong, Kang A1 - Jie, Yulin A1 - Adelhelm, Philipp A1 - Chen, Yawei A1 - Xu, Liang A1 - Yu, Peiping A1 - Kim, Junghwa A1 - Kochovski, Zdravko A1 - Yu, Zhilong A1 - Li, Wanxia A1 - LeBeau, James A1 - Shao-Horn, Yang A1 - Cao, Ruiguo A1 - Jiao, Shuhong A1 - Cheng, Tao A1 - Manke, Ingo A1 - Lu, Yan T1 - Promoting mechanistic understanding of lithium deposition and solid-electrolyte interphase (SEI) formation using advanced characterization and simulation methods: recent progress, limitations, and future perspectives JF - Avanced energy materials N2 - In recent years, due to its great promise in boosting the energy density of lithium batteries for future energy storage, research on the Li metal anode, as an alternative to the graphite anode in Li-ion batteries, has gained significant momentum. However, the practical use of Li metal anodes has been plagued by unstable Li (re)deposition and poor cyclability. Although tremendous efforts have been devoted to the stabilization of Li metal anodes, the mechanisms of electrochemical (re-)deposition/dissolution of Li and solid-electrolyte-interphase (SEI) formation remain elusive. This article highlights the recent mechanistic understandings and observations of Li deposition/dissolution and SEI formation achieved from advanced characterization techniques and simulation methods, and discusses major limitations and open questions in these processes. In particular, the authors provide their perspectives on advanced and emerging/potential methods for obtaining new insights into these questions. In addition, they give an outlook into cutting-edge interdisciplinary research topics for Li metal anodes. It pushes beyond the current knowledge and is expected to accelerate development toward a more in-depth and comprehensive understanding, in order to guide future research on Li metal anodes toward practical application. KW - advanced characterization KW - Li deposition KW - Li dissolution KW - Li metal KW - anodes KW - mechanistic understanding KW - solid-electrolyte-interphase KW - theoretical simulation Y1 - 2022 U6 - https://doi.org/10.1002/aenm.202200398 SN - 1614-6832 SN - 1614-6840 VL - 12 IS - 19 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Sandmann, Michael A1 - Münzberg, Marvin A1 - Bressel, Lena A1 - Reich, Oliver A1 - Hass, Roland T1 - Inline monitoring of high cell density cultivation of Scenedesmus rubescens in a mesh ultra-thin layer photobioreactor by photon density wave spectroscopy JF - BMC Research Notes / Biomed Central N2 - Objective Due to multiple light scattering that occurs inside and between cells, quantitative optical spectroscopy in turbid biological suspensions is still a major challenge. This includes also optical inline determination of biomass in bioprocessing. Photon Density Wave (PDW) spectroscopy, a technique based on multiple light scattering, enables the independent and absolute determination of optical key parameters of concentrated cell suspensions, which allow to determine biomass during cultivation. Results A unique reactor type, called "mesh ultra-thin layer photobioreactor" was used to create a highly concentrated algal suspension. PDW spectroscopy measurements were carried out continuously in the reactor without any need of sampling or sample preparation, over 3 weeks, and with 10-min time resolution. Conventional dry matter content and coulter counter measurements have been employed as established offline reference analysis. The PBR allowed peak cell dry weight (CDW) of 33.4 g L-1. It is shown that the reduced scattering coefficient determined by PDW spectroscopy is strongly correlated with the biomass concentration in suspension and is thus suitable for process understanding. The reactor in combination with the fiber-optical measurement approach will lead to a better process management. KW - Photon density wave spectroscopy KW - Multiple light scattering KW - Process KW - analytical technology KW - Fiber-optical spectroscopy KW - Mesh ultra-thin layer KW - photobioreactor Y1 - 2022 U6 - https://doi.org/10.1186/s13104-022-05943-2 SN - 1756-0500 VL - 15 IS - 1 PB - Biomed Central (London) CY - London ER - TY - JOUR A1 - Neusser, David A1 - Sun, Bowen A1 - Tan, Wen Liang A1 - Thomsen, Lars A1 - Schultz, Thorsten A1 - Perdigon-Toro, Lorena A1 - Koch, Norbert A1 - Shoaee, Safa A1 - McNeill, Christopher R. A1 - Neher, Dieter A1 - Ludwigs, Sabine T1 - Spectroelectrochemically determined energy levels of PM6:Y6 blends and their relevance to solar cell performance JF - Journal of materials chemistry : C, Materials for optical and electronic devices N2 - Recent advances in organic solar cell performance have been mainly driven forward by combining high-performance p-type donor-acceptor copolymers (e.g.PM6) and non-fullerene small molecule acceptors (e.g.Y6) as bulk-heterojunction layers. A general observation in such devices is that the device performance, e.g., the open-circuit voltage, is strongly dependent on the processing solvent. While the morphology is a typically named key parameter, the energetics of donor-acceptor blends are equally important, but less straightforward to access in the active multicomponent layer. Here, we propose to use spectral onsets during electrochemical cycling in a systematic spectroelectrochemical study of blend films to access the redox behavior and the frontier orbital energy levels of the individual compounds. Our study reveals that the highest occupied molecular orbital offset (Delta E-HOMO) in PM6:Y6 blends is similar to 0.3 eV, which is comparable to the binding energy of Y6 excitons and therefore implies a nearly zero driving force for the dissociation of Y6 excitons. Switching the PM6 orientation in the blend films from face-on to edge-on in bulk has only a minor influence on the positions of the energy levels, but shows significant differences in the open circuit voltage of the device. We explain this phenomenon by the different interfacial molecular orientations, which are known to affect the non-radiative decay rate of the charge-transfer state. We compare our results to ultraviolet photoelectron spectroscopy data, which shows distinct differences in the HOMO offsets in the PM6:Y6 blend compared to neat films. This highlights the necessity to measure the energy levels of the individual compounds in device-relevant blend films. Y1 - 2022 U6 - https://doi.org/10.1039/d2tc01918c SN - 2050-7526 SN - 2050-7534 VL - 10 IS - 32 SP - 11565 EP - 11578 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Mayer, Dennis A1 - Lever, Fabiano A1 - Picconi, David A1 - Metje, Jan A1 - Ališauskas, Skirmantas A1 - Calegari, Francesca A1 - Düsterer, Stefan A1 - Ehlert, Christopher A1 - Feifel, Raimund A1 - Niebuhr, Mario A1 - Manschwetus, Bastian A1 - Kuhlmann, Marion A1 - Mazza, Tommaso A1 - Robinson, Matthew Scott A1 - Squibb, Richard J. A1 - Trabattoni, Andrea A1 - Wallner, Måns A1 - Saalfrank, Peter A1 - Wolf, Thomas J. A. A1 - Gühr, Markus T1 - Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy JF - Nature communications N2 - Imaging the charge flow in photoexcited molecules would provide key information on photophysical and photochemical processes. Here the authors demonstrate tracking in real time after photoexcitation the change in charge density at a specific site of 2-thiouracil using time-resolved X-ray photoelectron spectroscopy. The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220-250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states. Y1 - 2022 U6 - https://doi.org/10.1038/s41467-021-27908-y SN - 2041-1723 N1 - Publisher correction: https://doi.org/10.1038/s41467-022-28584-2 VL - 13 IS - 1 PB - Nature Research CY - Berlin ER - TY - JOUR A1 - Kleinpeter, Erich A1 - Koch, Andreas T1 - Cyclazines-structure and aromaticity or antiaromaticity on the magnetic criterion JF - European journal of organic chemistry N2 - Structure and spatial magnetic properties, through-space NMR shieldings (TSNMRSs), of all ten cycl[2.2.2]azine to cycl[4.4.4]azine, hetero-analogues and the corresponding hydrocarbons have been calculated at the B3LYP/6-311G(d,p) theory level using the GIAO perturbation method and employing the nucleus independent chemical shift (NICS) concept. The TSNMRS values (actually, the ring current effect as measurable in H-1 NMR spectroscopy) are visualized as iso-chemical-shielding surfaces (ICSS) of various size and direction, and employed to readily qualify and quantify the degree of (anti)aromaticity. Results are confirmed by NMR [delta(H-1)/ppm, delta(N-15)/ppm] and geometry (planar, twisted, bow-shaped) data. The cyclazines N[2.2.2](-) up to N[2.4.4](-) are planar or at most slightly bowl-shaped and, due to coherent peripheral ring currents (except in N[2.3.3](-), N[2.3.4], N[3.3.4](+) and N[2.4.4](+)), develop aromaticity or anti-aromaticity of the whole molecules dependent on the number of peripheral conjugated pi electrons. The cyclazines N[2.3.3](-), N[2.3.4], N[3.3.4](+) and N[2.4.4](+) develop two ring currents of different direction within the same molecule, in which the dominating ring current proves to be paratropic (in N[3.3.4](+) diatropic) including the nodal N p(z) lone pair into the conjugation. The residual cyclazines N[3.4.4], N[4.4.4](-) and N[4.4.4](+) are heavily twisted and, therefore, are not developing peripheral or diverse ring currents. The TSNMRS information about cyclazines and the parent tricyclic annulene analogues is congruent subject to structure and number of peripheral or internal conjugated pi electrons, the corresponding (anti)aromaticity is in unequivocal accordance with Huckel's rule. KW - Aromaticity KW - Cyclazines KW - NMR spectroscopy KW - Peripheral ring current Y1 - 2022 U6 - https://doi.org/10.1002/ejoc.202101362 SN - 1434-193X SN - 1099-0690 VL - 2022 IS - 8 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Göttlich, Richard A1 - Graulich, Nicole A1 - Huwer, Johannes A1 - Banerji, Amitabh T1 - Analog und digital BT - Chemieunterricht mit Potenzial JF - Chemie konkret : CHEMKON ; Forum für Unterricht und Didaktik Y1 - 2022 U6 - https://doi.org/10.1002/ckon.202200046 SN - 0944-5846 SN - 1521-3730 VL - 29 SP - 182 EP - 182 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Mayer, Dennis A1 - Lever, Fabiano A1 - Picconi, David A1 - Metje, Jan A1 - Ališauskas, Skirmantas A1 - Calegari, Francesca A1 - Düsterer, Stefan A1 - Ehlert, Christopher A1 - Feifel, Raimund A1 - Niebuhr, Mario A1 - Manschwetus, Bastian A1 - Kuhlmann, Marion A1 - Mazza, Tommaso A1 - Robinson, Matthew Scott A1 - Squibb, Richard James A1 - Trabattoni, Andrea A1 - Wallner, Måns A1 - Saalfrank, Peter A1 - Wolf, Thomas J. A. A1 - Gühr, Markus T1 - Following excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy JF - Nature Communications N2 - The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the charge motion at a specific site in an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). We extend the concept of static chemical shift from conventional XPS by the excited-state chemical shift (ESCS), which is connected to the charge in the framework of a potential model. This allows us to invert TR-XPS spectra to the dynamic charge at a specific atom. We demonstrate the power of TR-XPS by using sulphur 2p-core-electron-emission probing to study the UV-excited dynamics of 2-thiouracil. The method allows us to discover that a major part of the population relaxes to the molecular ground state within 220–250 fs. In addition, a 250-fs oscillation, visible in the kinetic energy of the TR-XPS, reveals a coherent exchange of population among electronic states. Y1 - 2022 U6 - https://doi.org/10.1038/s41467-021-27908-y SN - 2041-1723 VL - 13 PB - Springer Nature CY - Berlin ER - TY - JOUR A1 - Brinkmann, Pia A1 - Köllner, Nicole A1 - Merk, Sven A1 - Beitz, Toralf A1 - Altenberger, Uwe A1 - Löhmannsröben, Hans-Gerd T1 - Comparison of handheld and echelle spectrometer to assess copper in ores by means of laser-induced breakdown spectroscopy (LIBS) JF - Minerals N2 - Its properties make copper one of the world’s most important functional metals. Numerous megatrends are increasing the demand for copper. This requires the prospection and exploration of new deposits, as well as the monitoring of copper quality in the various production steps. A promising technique to perform these tasks is Laser Induced Breakdown Spectroscopy (LIBS). Its unique feature, among others, is the ability to measure on site without sample collection and preparation. In this work, copper-bearing minerals from two different deposits are studied. The first set of field samples come from a volcanogenic massive sulfide (VMS) deposit, the second part from a stratiform sedimentary copper (SSC) deposit. Different approaches are used to analyze the data. First, univariate regression (UVR) is used. However, due to the strong influence of matrix effects, this is not suitable for the quantitative analysis of copper grades. Second, the multivariate method of partial least squares regression (PLSR) is used, which is more suitable for quantification. In addition, the effects of the surrounding matrices on the LIBS data are characterized by principal component analysis (PCA), alternative regression methods to PLSR are tested and the PLSR calibration is validated using field samples. KW - LIBS KW - copper-bearing minerals KW - UVR KW - PCA KW - PLSR Y1 - 2023 U6 - https://doi.org/10.3390/min13010113 SN - 2075-163X VL - 13 IS - 1 PB - MDPI CY - Basel ER - TY - JOUR A1 - Dettmann, Sophie A1 - Huittinen, Nina Maria A1 - Nicolas, Jahn A1 - Kretzschmar, Jerome A1 - Kumke, Michael A1 - Kutyma, Tamara A1 - Lohmann, Janik A1 - Reich, Tobias A1 - Schmeide, Katja A1 - Azzam, Salim Shams Aldin A1 - Spittler, Leon A1 - Stietz, Janina T1 - Influence of gluconate on the retention of Eu(III), Am(III), Th(IV), Pu(IV), and U(VI) by C-S-H (C/S = 0.8) JF - Frontiers in Nuclear Engineering N2 - The retention of actinides in different oxidation states (An(X), X = III, IV, VI) by a calcium-silicate-hydrate (C-S-H) phase with a Ca/Si (C/S) ratio of 0.8 was investigated in the presence of gluconate (GLU). The actinides considered were Am(III), Th(IV), Pu(IV), and U(VI). Eu(III) was investigated as chemical analogue for Am(III) and Cm(III). In addition to the ternary systems An(X)/GLU/C-S-H, also binary systems An(X)/C-S-H, GLU/C-S-H, and An(X)/GLU were studied. Complementary analytical techniques were applied to address the different specific aspects of the binary and ternary systems. Time-resolved laser-induced luminescence spectroscopy (TRLFS) was applied in combination with parallel factor analysis (PARAFAC) to identify retained species and to monitor species-selective sorption kinetics. ¹³C and ²⁹Si magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were applied to determine the bulk structure and the composition of the C-S-H surface, respectively, in the absence and presence of GLU. The interaction of Th(IV) with GLU in different electrolytes was studied by capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS). The influence of GLU on An(X) retention was investigated for a large concentration range up to 10⁻² M. The results showed that GLU had little to no effect on the overall An(X) retention by C-S-H with C/S of 0.8, regardless of the oxidation state of the actinides. For Eu(III), the TRLFS investigations additionally implied the formation of a Eu(III)-bearing precipitate with dissolved constituents of the C-S-H phase, which becomes structurally altered by the presence of GLU. For U(VI) sorption on the C-S-H phase, only a small influence of GLU could be established in the luminescence spectroscopic investigations, and no precipitation of U(VI)-containing secondary phases could be identified. KW - actinide KW - organic ligand KW - sorption KW - cementitious material KW - concrete KW - luminescence Y1 - 2023 U6 - https://doi.org/10.3389/fnuen.2023.1124856 SN - 2813-3412 VL - 2 PB - Frontiers Media CY - Lausanne ER - TY - JOUR A1 - Sperlich, Eric A1 - Köckerling, Martin T1 - The double cluster compound [Nb6Cl14(MeCN)(4)] [Nb6Cl14(pyz)(4)].6MeCN (Me: methyl, pyz: pyrazine) with a layered structure resulting from weak intermolecular interactions JF - Zeitschrift für Naturforschung N2 - The synthesis and the crystal structure of the double cluster compound [Nb6Cl14(MeCN)(4)][Nb6Cl14(pyz)(4)]middot6CH(3)CN are described. The synthesis is based on a partial ligand exchange reaction, which proceeds upon dissolving [Nb6Cl14(pyz)(4)]middot2CH(2)Cl(2) in acetonitrile. The compound is built up of two discrete neutral cluster units, which consist of octahedra of Nb-6 atoms coordinated by 12 edge-bridging chlorido and two terminal chlorido ligands, and four acetonitrile ligands on one and four pyrazine ligands on the other cluster unit. Co-crystallized acetonitrile molecules are also present. The single-crystal structure determination has revealed a cluster arrangement in which the [Nb6Cl14(pyz)(4)] units are connected by (halogen) lone-pair-(pyrazine) pi interactions. These lead to chains of [Nb6Cl14(pyz)(4)] clusters. These chains are further connected to cluster layers by (nitrile-halogen) dipole-dipole interactions, in which the [Nb6Cl14(MeCN)(4)] and co-crystallized MeCN molecules are also involved. These cluster layers are arranged parallel to the crystallographic {011} plane. KW - cluster KW - crystal structure KW - dipole-dipole interaction KW - halide KW - lone-pair-pi interactions KW - niobium Y1 - 2023 U6 - https://doi.org/10.1515/znb-2023-0001 SN - 0932-0776 SN - 1865-7117 VL - 78 IS - 5 SP - 279 EP - 283 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Akampurira, Denis A1 - Akala, Hoseah M. A1 - Derese, Solomon A1 - Heydenreich, Matthias A1 - Yenesew, Abiy T1 - A new C-C linked benzophenathridine-2-quinoline dimer, and the antiplasmodial activity of alkaloids from Zanthoxylum holstzianum JF - Natural product research N2 - The CH2Cl2/MeOH (1:1) extract of Zanthoxylum holstzianum stem bark showed good antiplasmodial activity (IC50 2.5 +/- 0.3 and 2.6 +/- 0.3 mu g/mL against the W2 and D6 strains of Plasmodium falciparum, respectively). From the extract five benzophenanthridine alkaloids [8-acetonyldihydrochelerythrine (1), nitidine (2), dihydrochelerythine (3), norchelerythrine (5), arnottianamide (8)]; a 2-quinolone alkaloid [N-methylflindersine (4)]; a lignan [4,4 '-dihydroxy-3,3 '-dimethoxylignan-9,9 '-diyl diacetate (7)] and a dimer of a benzophenanthridine and 2-quinoline [holstzianoquinoline (6)] were isolated. The CH2Cl2/MeOH (1:1) extract of the root bark afforded 1, 3-6, 8, chelerythridimerine (9) and 9-demethyloxychelerythrine (10). Holstzianoquinoline (6) is new, and is the second dimer linked by a C-C bond of a benzophenanthridine and a 2-quinoline reported thus far. The compounds were identified based on spectroscopic evidence. Amongst five compounds (1-5) tested against two strains of P. falciparum, nitidine (IC50 0.11 +/- 0.01 mu g/mL against W2 and D6 strains) and norchelerythrine (IC50 value of 0.15 +/- 0.01 mu g/mL against D6 strain) were the most active. KW - Antiplasmodial KW - benzophenanthridine alkaloid KW - holstzianoquinoline; KW - rutaceae KW - Zanthoxylum holstzianum Y1 - 2022 U6 - https://doi.org/10.1080/14786419.2022.2034810 SN - 1478-6419 SN - 1478-6427 VL - 37 IS - 13 SP - 2161 EP - 2171 PB - Taylor & Francis CY - London [u.a.] ER - TY - JOUR A1 - Hu, Neng A1 - Lin, Li A1 - Metwalli, Ezzeldin A1 - Bießmann, Lorenz A1 - Philipp, Martine A1 - Hildebrand, Viet A1 - Laschewsky, André A1 - Papadakis, Christine M. A1 - Cubitt, Robert A1 - Zhong, Qi A1 - Müller-Buschbaum, Peter T1 - Kinetics of water transfer between the LCST and UCST thermoresponsive blocks in diblock copolymer thin films monitored by in situ neutron reflectivity JF - Advanced materials interfaces N2 - The kinetics of water transfer between the lower critical solution temperature (LCST) and upper critical solution temperature (UCST) thermoresponsive blocks in about 10 nm thin films of a diblock copolymer is monitored by in situ neutron reflectivity. The UCST-exhibiting block in the copolymer consists of the zwitterionic poly(4((3-methacrylamidopropyl)dimethylammonio)butane-1-sulfonate), abbreviated as PSBP. The LCST-exhibiting block consists of the nonionic poly(N-isopropylacrylamide), abbreviated as PNIPAM. The as-prepared PSBP80-b-PNIPAM(400) films feature a three-layer structure, i.e., PNIPAM, mixed PNIPAM and PSBP, and PSBP. Both blocks have similar transition temperatures (TTs), namely around 32 degrees C for PNIPAM, and around 35 degrees C for PSBP, and with a two-step heating protocol (20 degrees C to 40 degrees C and 40 degrees C to 80 degrees C), both TTs are passed. The response to such a thermal stimulus turns out to be complex. Besides a three-step process (shrinkage, rearrangement, and reswelling), a continuous transfer of D2O from the PNIPAM to the PSBP block is observed. Due to the existence of both, LCST and UCST blocks in the PSBP80-b-PNIPAM(400 )film, the water transfer from the contracting PNIPAM, and mixed layers to the expanding PSBP layer occurs. Thus, the hydration kinetics and thermal response differ markedly from a thermoresponsive polymer film with a single LCST transition. KW - block copolymer KW - dual thermoresponsive KW - kinetic water transfer KW - neutron KW - reflectivity KW - thin film Y1 - 2022 U6 - https://doi.org/10.1002/admi.202201913 SN - 2196-7350 VL - 10 IS - 3 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Bhattacharyya, Biswajit A1 - Balischewski, Christian A1 - Sperlich, Eric A1 - Günter, Christina A1 - Mies, Stefan A1 - Kelling, Alexandra A1 - Taubert, Andreas T1 - N-Butyl Pyridinium Diiodido Argentate(I) BT - A One-Dimensional Ag-I Network with Superior Solid-State Ionic Conductivity at Room Temperature JF - Advanced materials interfaces N2 - A new solid-state material, N-butyl pyridinium diiodido argentate(I), is synthesized using a simple and effective one-pot approach. In the solid state, the compound exhibits 1D ([AgI2](-))(n) chains that are stabilized by the N-butyl pyridinium cation. The 1D structure is further manifested by the formation of long, needle-like crystals, as revealed from electron microscopy. As the general composition is derived from metal halide-based ionic liquids, the compound has a low melting point of 100-101 degrees C, as confirmed by differential scanning calorimetry. Most importantly, the compound has a conductivity of 10(-6) S cm(-1) at room temperature. At higher temperatures the conductivity increases and reaches to 10(-4 )S cm(-1) at 70 degrees C. In contrast to AgI, however, the current material has a highly anisotropic 1D arrangement of the ionic domains. This provides direct and tuneable access to fast and anisotropic ionic conduction. The material is thus a significant step forward beyond current ion conductors and a highly promising prototype for the rational design of highly conductive ionic solid-state conductors for battery or solar cell applications. KW - AgI KW - ionic conductivity KW - Ionic liquids KW - thermal properties Y1 - 2023 U6 - https://doi.org/10.1002/admi.202202363 SN - 2196-7350 VL - 10 IS - 12 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Nchiozem-Ngnitedem, Vaderament-Alexe A1 - Sperlich, Eric A1 - Matieta, Valaire Yemene A1 - Kuete, Jenifer Reine Ngnouzouba A1 - Kuete, Victor A1 - Omer, Ejlal A. A. A1 - Efferth, Thomas A1 - Schmidt, Bernd T1 - Synthesis and bioactivity of isoflavones from ficus carica and some non-natural analogues JF - Journal of natural products : Lloydia N2 - FicucariconeD (1) and its 4 '-demethyl congener 2 are isoflavones isolated from fruits of Ficus carica that share a 5,7-dimethoxy-6-prenyl-substituted A-ring. Both naturalproducts were, for the first time, obtained by chemical synthesisin six steps, starting from 2,4,6-trihydroxyacetophenone. Key stepsare a microwave-promoted tandem sequence of Claisen- and Cope-rearrangementsto install the 6-prenyl substituent and a Suzuki-Miyaura crosscoupling for installing the B-ring. By using various boronic acids,non-natural analogues become conveniently available. All compoundswere tested for cytotoxicity against drug-sensitive and drug-resistanthuman leukemia cell lines, but were found to be inactive. The compoundswere also tested for antimicrobial activities against a panel of eightGram-negative and two Gram-positive bacterial strains. Addition ofthe efflux pump inhibitor phenylalanine-arginine-beta-naphthylamide(PA beta N) significantly improved the antibiotic activity in mostcases, with MIC values as low as 2.5 mu M and activity improvementfactors as high as 128-fold. KW - Antimicrobial activity KW - Bacteria KW - Ethers KW - Flavonoids KW - Mixtures Y1 - 2023 U6 - https://doi.org/10.1021/acs.jnatprod.3c00219 SN - 0163-3864 SN - 1520-6025 VL - 86 IS - 6 SP - 1520 EP - 1528 PB - American Chemical Society CY - Washington, DC ER - TY - JOUR A1 - Reitenbach, Julija A1 - Geiger, Christina A1 - Wang, Peixi A1 - Vagias, Apostolos N. A1 - Cubitt, Robert A1 - Schanzenbach, Dirk A1 - Laschewsky, André A1 - Papadakis, Christine M. A1 - Müller-Buschbaum, Peter T1 - Effect of magnesium salts with chaotropic anions on the swelling behavior of PNIPMAM thin films JF - Macromolecules : a publication of the American Chemical Society N2 - Poly(N-isopropylmethacrylamide) (PNIPMAM) is a stimuli responsive polymer, which in thin film geometry exhibits a volume-phase transition upon temperature increase in water vapor. The swelling behavior of PNIPMAM thin films containing magnesium salts in water vapor is investigated in view of their potential application as nanodevices. Both the extent and the kinetics of the swelling ratio as well as the water content are probed with in situ time-of-flight neutron reflectometry. Additionally, in situ Fourier-transform infrared (FTIR) spectroscopy provides information about the local solvation of the specific functional groups, while two-dimensional FTIR correlation analysis further elucidates the temporal sequence of solvation events. The addition of Mg(ClO4)2 or Mg(NO3)2 enhances the sensitivity of the polymer and therefore the responsiveness of switches and sensors based on PNIPMAM thin films. It is found that Mg(NO3)2 leads to a higher relative water uptake and therefore achieves the highest thickness gain in the swollen state. Y1 - 2023 U6 - https://doi.org/10.1021/acs.macromol.2c02282 SN - 0024-9297 SN - 1520-5835 VL - 56 IS - 2 SP - 567 EP - 577 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Kleinpeter, Erich A1 - Koch, Andreas T1 - The multiple bond character of the carbon-boron bond in boron trapped N-heterocyclic carbenes (NHCs) and cyclic(alkyl)(amino) carbenes (CAACs) on the magnetic criterion JF - Tetrahedron N2 - Geometry, 11B, 13C chemical shifts and the spatial magnetic properties (Through-Space NMR Shieldings -TSNMRS) of both cations and anions of boron-trapped N-heterocyclic carbenes (NHCs) and cyclic (alkyl)(amino)carbenes (CAACs) and of the corresponding diborane/diborene/diboryne dis-carbene adducts have been calculated using the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept; the TSNMRS results are visualized as iso-chemical-shielding surfaces (ICSS) of various size and direction. The ICSS of the TSNMRS (actually the anisotropy effects measurable in 1H NMR spectroscopy) are employed to qualify and quantify the present multiple bond character of the Carbene-Boron bond in the trapped NHCs and CAACs. Results are confirmed by bond length and 11B/13C chemical shift variations. Thus the partial multiple bond character of the Carbene-Boron bond cannot be expressed by the arrow of weak, much longer dative bonds and should be omitted as in other covalent lone pair-it or triel bonds. & COPY; 2023 Elsevier Ltd. All rights reserved. KW - NHCs KW - CAACs KW - Multiple NHC(CAAC)-Boron bonds KW - Through -space NMR KW - shieldings (TSNMRS) KW - NICS KW - Anisotropy effect KW - Ring current effect Y1 - 2023 U6 - https://doi.org/10.1016/j.tet.2023.133469 SN - 0040-4020 SN - 1464-5416 VL - 140 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Mazarei, Elham A1 - Penschke, Christopher A1 - Saalfrank, Peter T1 - Band gap engineering in two-dimensional materials by functionalization BT - Methylation of graphene and graphene bilayers JF - ACS Omega N2 - Graphene is well-knownfor its unique combination of electricaland mechanical properties. However, its vanishing band gap limitsthe use of graphene in microelectronics. Covalent functionalizationof graphene has been a common approach to address this critical issueand introduce a band gap. In this Article, we systematically analyzethe functionalization of single-layer graphene (SLG) and bilayer graphene(BLG) with methyl (CH3) using periodic density functionaltheory (DFT) at the PBE+D3 level of theory. We also include a comparisonof methylated single-layer and bilayer graphene, as well as a discussionof different methylation options (radicalic, cationic, and anionic).For SLG, methyl coverages ranging from 1/8 to 1/1, (i.e.,the fully methylated analogue of graphane) are considered. We findthat up to a coverage theta of 1/2, graphene readily accepts CH3, with neighbor CH3 groups preferring trans positions. Above theta = 1/2, the tendency to accept further CH3 weakens and the lattice constant increases. The band gapbehaves less regularly, but overall it increases with increasing methylcoverage. Thus, methylated graphene shows potential for developingband gap-tuned microelectronics devices and may offer further functionalizationoptions. To guide in the interpretation of methylation experiments,vibrational signatures of various species are characterized by normal-modeanalysis (NMA), their vibrational density of states (VDOS), and infrared(IR) spectra, the latter two are obtained from ab initio moleculardynamics (AIMD) in combination with a velocity-velocity autocorrelationfunction (VVAF) approach. KW - Adsorption KW - Alkyls KW - Band structure KW - Electrical conductivity KW - Two dimensional materials Y1 - 2023 U6 - https://doi.org/10.1021/acsomega.3c02068 SN - 2470-1343 VL - 8 IS - 24 SP - 22026 EP - 22041 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Adesina, Morenike O. A1 - Block, Inga A1 - Günter, Christina A1 - Unuabonah, Emmanuel Iyayi A1 - Taubert, Andreas T1 - Efficient Removal of Tetracycline and Bisphenol A from Water with a New Hybrid Clay/TiO2 Composite JF - ACS Omega N2 - New TiO2 hybrid composites were prepared fromkaolinclay, predried and carbonized biomass, and titanium tetraisopropoxideand explored for tetracycline (TET) and bisphenol A (BPA) removalfrom water. Overall, the removal rate is 84% for TET and 51% for BPA.The maximum adsorption capacities (q (m))are 30 and 23 mg/g for TET and BPA, respectively. These capacitiesare far greater than those obtained for unmodified TiO2. Increasing the ionic strength of the solution does not change theadsorption capacity of the adsorbent. pH changes only slightly changeBPA adsorption, while a pH > 7 significantly reduces the adsorptionof TET on the material. The Brouers-Sotolongo fractal modelbest describes the kinetic data for both TET and BPA adsorption, predictingthat the adsorption process occurs via a complex mechanism involvingvarious forces of attraction. Temkin and Freundlich isotherms, whichbest fit the equilibrium adsorption data for TET and BPA, respectively,suggest that adsorption sites are heterogeneous in nature. Overall,the composite materials are much more effective for TET removal fromaqueous solution than for BPA. This phenomenon is assigned to a differencein the TET/adsorbent interactions vs the BPA/adsorbent interactions:the decisive factor appears to be favorable electrostatic interactionsfor TET yielding a more effective TET removal. Y1 - 2023 U6 - https://doi.org/10.1021/acsomega.3c00184 SN - 2470-1343 VL - 8 IS - 24 SP - 21594 EP - 21604 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Erler, Alexander A1 - Riebe, Daniel A1 - Beitz, Toralf A1 - Löhmannsröben, Hans-Gerd A1 - Leenen, Mathias A1 - Pätzold, Stefan A1 - Ostermann, Markus A1 - Wójcik, Michał T1 - Mobile laser-induced breakdown spectroscopy for future application in precision agriculture BT - a case study JF - Sensors N2 - In precision agriculture, the estimation of soil parameters via sensors and the creation of nutrient maps are a prerequisite for farmers to take targeted measures such as spatially resolved fertilization. In this work, 68 soil samples uniformly distributed over a field near Bonn are investigated using laser-induced breakdown spectroscopy (LIBS). These investigations include the determination of the total contents of macro- and micronutrients as well as further soil parameters such as soil pH, soil organic matter (SOM) content, and soil texture. The applied LIBS instruments are a handheld and a platform spectrometer, which potentially allows for the single-point measurement and scanning of whole fields, respectively. Their results are compared with a high-resolution lab spectrometer. The prediction of soil parameters was based on multivariate methods. Different feature selection methods and regression methods like PLS, PCR, SVM, Lasso, and Gaussian processes were tested and compared. While good predictions were obtained for Ca, Mg, P, Mn, Cu, and silt content, excellent predictions were obtained for K, Fe, and clay content. The comparison of the three different spectrometers showed that although the lab spectrometer gives the best results, measurements with both field spectrometers also yield good results. This allows for a method transfer to the in-field measurements. KW - LIBS KW - precision agriculture KW - soil KW - multivariate methods KW - feature selection Y1 - 2023 U6 - https://doi.org/10.3390/s23167178 SN - 1424-8220 VL - 23 IS - 16 PB - MDPI CY - Basel ER - TY - JOUR A1 - Schlappa, Stephanie A1 - Bressel, Lena A1 - Reich, Oliver A1 - Münzberg, Marvin T1 - Advanced particle size analysis in high-solid-content polymer dispersions using photon density wave spectroscopy JF - Polymers N2 - High-solid-content polystyrene and polyvinyl acetate dispersions of polymer particles with a 50 nm to 500 nm mean particle diameter and 12-55% (w/w) solid content have been produced via emulsion polymerization and characterized regarding their optical and physical properties. Both systems have been analyzed with common particle-size-measuring techniques like dynamic light scattering (DLS) and static light scattering (SLS) and compared to inline particle size distribution (PSD) measurements via photon density wave (PDW) spectroscopy in undiluted samples. It is shown that particle size measurements of undiluted polystyrene dispersions are in good agreement between analysis methods. However, for polyvinyl acetate particles, size determination is challenging due to bound water in the produced polymer. For the first time, water-swelling factors were determined via an iterative approach of PDW spectroscopy error (X-2) minimization. It is shown that water-swollen particles can be analyzed in high-solid-content solutions and their physical properties can be assumed to determine the refractive index, density, and volume fraction in dispersion. It was found that assumed water swelling improved the reduced scattering coefficient fit by PDW spectroscopy by up to ten times and particle size determination was refined and enabled. Particle size analysis of the water-swollen particles agreed well with offline-based state-of-the-art techniques. KW - emulsion polymerization KW - multiple light scattering KW - photon density wave KW - spectroscopy KW - particle sizing KW - swelling of polymers Y1 - 2023 U6 - https://doi.org/10.3390/polym15153181 SN - 2073-4360 VL - 15 IS - 15 PB - MDPI CY - Basel ER -