@article{63960, abstract = {{Recent advances in solid-state nuclear magnetic resonance (NMR) spectroscopy and dynamic nuclear polarization (DNP) of nanostructured materials are reviewed. A first group of materials is based on crystalline nanocellulose (CNC) or microcrystalline cellulose (MCC), which are used as carrier materials for dye molecules, catalysts or in combination with heterocyclic molecules as ion conducting membranes. These materials have widespread applications in sensorics, optics, catalysis or fuel cell research. A second group are metal oxides such as V-Mo-W oxides, which are of enormous importance in the manufacturing process of basic chemicals. The third group are catalytically active nanocrystalline metal nanoparticles, coated with protectants or embedded in polymers. The last group includes of lead-free perovskite materials, which are employed as environmentally benign substitution materials for conventional lead-based electronics materials. These materials are discussed in terms of their application and physico-chemical characterization by solid-state NMR techniques, combined with gas-phase NMR and quantum-chemical modelling on the density functional theory (DFT) level. The application of multinuclear 1H, 2H, 13C, 15N and 23Na solid state NMR techniques under static or MAS conditions for the characterization of these materials, their surfaces and processes on their surfaces is discussed. Moreover, the analytic power of the combination of these techniques with DNP for the identification of low-concentrated carbon and nitrogen containing surface species in natural abundance is reviewed. Finally, approaches for sensitivity enhancement by DNP of quadrupolar nuclei such as 17O and 51V are presented that enable the identification of catalytic sites in metal oxide catalysts.}}, author = {{Gutmann, Torsten and Groszewicz, Pedro B. and Buntkowsky, Gerd}}, journal = {{Annual Reports on NMR Spectroscopy}}, keywords = {{solid-state nmr, heterogeneous catalysis, dynamic nuclear polarization, Ferroelectrics, Nanocatalysis, Surface reactions}}, pages = {{1–82}}, title = {{{Solid-state NMR of nanocrystals}}}, doi = {{10.1016/bs.arnmr.2018.12.001}}, volume = {{97}}, year = {{2019}}, } @article{63930, abstract = {{Abstract Specific spin labeling allows the site-selective investigation of biomolecules by EPR and DNP enhanced NMR spectroscopy. A novel spin labeling strategy for commercially available Fmoc-amino acids is developed. In this approach, the PROXYL spin label is covalently attached to the hydroxyl side chain of three amino acids hydroxyproline (Hyp), serine (Ser) and tyrosine (Tyr) by a simple three-step synthesis route. The obtained PROXYL containing building-blocks are N-terminally protected by the Fmoc-protection group, which makes them applicable for the use in solid-phase peptide synthesis (SPPS). This approach allows the insertion of the spin label at any desired position during SPPS, which makes it more versatile than the widely used post synthetic spin labeling strategies. For the final building-blocks, the radical activity is proven by EPR. DNP enhanced solid-state NMR experiments employing these building-blocks in a TCE solution show enhancement factors of up to 26 for 1H and 13C (1H→13C cross-polarization). To proof the viability of the presented building-blocks for insertion of the spin label during SPPS the penta-peptide Acetyl-Gly-Ser(PROXYL)-Gly-Gly-Gly was synthesized employing the spin labeled Ser building-block. This peptide could successfully be isolated and the spin label activity proved by EPR and DNP NMR measurements, showing enhancement factors of 12.1±0.1 for 1H and 13.9±0.5 for 13C (direct polarization).}}, author = {{Brodrecht, Martin and Herr, Kevin and Bothe, Sarah and de Oliveira Jr., Marcos and Gutmann, Torsten and Buntkowsky, Gerd}}, journal = {{ChemPhysChem}}, number = {{11}}, pages = {{1475–1487}}, title = {{{Efficient Building Blocks for Solid-Phase Peptide Synthesis of Spin Labeled Peptides for Electron Paramagnetic Resonance and Dynamic Nuclear Polarization Applications}}}, doi = {{10.1002/cphc.201900211}}, volume = {{20}}, year = {{2019}}, } @article{63931, abstract = {{Abstract The structure and surface functionalization of biologically relevant silica-based hybrid materials was investigated by 2D solid-state NMR techniques combined with dynamic nuclear polarization (DNP). This approach was applied to a model system of mesoporous silica, which was modified through in-pore grafting of small peptides by solid-phase peptide synthesis (SPPS). To prove the covalent binding of the peptides on the surface, DNP-enhanced solid-state NMR was used for the detection of 15N NMR signals in natural abundance. DNP-enhanced heterocorrelation experiments with frequency switched Lee–Goldburg homonuclear proton decoupling (1H–13C and 1H–15N CP MAS FSLG HETCOR) were performed to verify the primary structure and configuration of the synthesized peptides. 1H FSLG spectra and 1H-29Si FSLG HETCOR correlation spectra were recorded to investigate the orientation of the amino acid residues with respect to the silica surface. The combination of these NMR techniques provides detailed insights into the structure of amino acid functionalized hybrid compounds and allows for the understanding for each synthesis step during the in-pore SPPS.}}, author = {{Brodrecht, Martin and Kumari, Bharti and Thankamony, A. S. Sofia Lilly and Breitzke, Hergen and Gutmann, Torsten and Buntkowsky, Gerd}}, journal = {{Chemistry A European Journal}}, number = {{20}}, pages = {{5214–5221}}, title = {{{Structural Insights into Peptides Bound to the Surface of Silica Nanopores}}}, doi = {{10.1002/chem.201805480}}, volume = {{25}}, year = {{2019}}, } @article{64054, abstract = {{In this work, the preparation of porous hybrid particle-based films by core-shell particle design and convenient film preparation is reported. Monodisperse core particles consisting of poly(methyl methacrylate‑co‑allyl methacrylate) (P(MMA‑co‑ALMA)) were synthesized by starved-feed emulsion polymerization followed by the introduction of an initiator-containing monomer (inimer) for subsequent atom transfer radical polymerization (ATRP). The inimer shell allowed for the introduction of allylhydrido polycarbosilane (SMP-10) under ATRP conditions by grafting to the core particles. The functionalization of the prepared core-shell particles was investigated by IR spectroscopy (FTIR), scanning transmission electron microscopy (STEM) and solid-state NMR combined with dynamic nuclear polarization (DNP). The obtained hard core/soft preceramic shell particles were subjected to the melt-shear organization technique, enabling a convenient alignment into a colloidal crystal structure in one single step without the presence of a dispersion medium or solvent for the designed particles. Moreover, the hybrid particle-based films were converted into a porous ceramic structure upon thermal treatment. As a result, freestanding ceramic porous films have been obtained after degradation of the organic template core particles. Noteworthy, the conversion of the matrix material consisting of SMP-10 into the ceramic occurred with preservation of the pristine colloidal crystal template structure. Herein, the first example of core-shell particle preparation by combining different polymerization methodologies and application of the convenient melt-shear organization technique is shown, paving a new way to ceramic materials with tailored morphology and porosity.}}, author = {{Vowinkel, Steffen and Boehm, Anna and Schäfer, Timmy and Gutmann, Torsten and Ionescu, Emanuel and Gallei, Markus}}, journal = {{Materials & Design}}, keywords = {{emulsion polymerization, self-assembly, ATRP, Colloidal crystal, Hybrid film, Particle processing}}, pages = {{926–935}}, title = {{{Preceramic core-shell particles for the preparation of hybrid colloidal crystal films by melt-shear organization and conversion into porous ceramics}}}, doi = {{10.1016/j.matdes.2018.10.032}}, volume = {{160}}, year = {{2018}}, } @article{64031, abstract = {{The activation of C-H bonds of alkanes remains a major challenge for chemistry. In a series of deuteration experiments with D-2 in contact with bis-(diphenylphosphino) butane (dppb) stabilized ruthenium nanoparticles (liquid substrates, 60 degrees C, 6 bar D-2) we have observed a surprisingly large reactivity of cyclopentane as compared to cyclohexane and other alkanes. DFT calculations using a ligand-free Ru13H17 model cluster as catalyst indicate oxidative C-H cleavage of the bound substrates as rate limiting reaction step. They also indicate similar binding and activation enthalpies of reactions of cyclopentane and cyclohexane.}}, author = {{Rothermel, N. and Bouzouita, D. and Rother, T. and Rosal, I. and Tricard, S. and Poteau, R. and Gutmann, Torsten and Chaudret, B. and Limbach, H. H. and Buntkowsky, G.}}, journal = {{ChemCatChem}}, number = {{19}}, pages = {{4243–4247}}, title = {{{Surprising Differences of Alkane C-H Activation Catalyzed by Ruthenium Nanoparticles: Complex Surface-Substrate Recognition?}}}, doi = {{10.1002/cctc.201801022}}, volume = {{10}}, year = {{2018}}, } @article{64007, abstract = {{The equilibration of H2, HD and D2 between the gas phase and surface hydrides of solid organic-ligand-stabilized Ru metal nanoparticles has been studied by gas phase 1H NMR spectroscopy using closed NMR tubes as batch reactors at room temperature and 800 mbar. When two different nanoparticle systems, Ru/PVP (PVP [identical with] polyvinylpyrrolidone) and Ru/HDA (HDA [identical with] hexadecylamine) were exposed to D2 gas, only the release of HD from the hydride containing surface could be detected in the initial stages of the reaction, but no H2. In the case of Ru/HDA also the reverse experiment was performed where surface deuterated nanoparticles were exposed to H2. In that case, the conversion of H2 into gaseous HD was detected. In order to analyze the experimental kinetic and spectroscopic data, we explored two different mechanisms taking into account potential kinetic and equilibrium H/D isotope effects. Firstly, we explored the dissociative exchange mechanism consisting of dissociative adsorption of dihydrogen, fast hydride surface diffusion and associative desorption of dihydrogen. It is shown that if D2 is the reaction partner, only H2 will be released in the beginning of the reaction, and HD only in later reaction stages. The second mechanism, dubbed here associative exchange consists of the binding of dihydrogen to Ru surface atoms, followed by a H-transfer to or by H-exchange with an adjacent hydride site, and finally of the associative desorption of dihydrogen. In that case, in the exchange with D2, only HD will be released in the beginning of the reaction. Our experimental results are not compatible with the dissociative exchange but can be explained in terms of the associative exchange. Whereas the former will dominate at low temperatures and pressures, the latter will prevail around room temperature and normal pressures where transition metal nanoparticles are generally used as reaction catalysts.}}, author = {{Limbach, Hans-Heinrich and Pery, Tal and Rothermel, Niels and Chaudret, Bruno and Gutmann, Torsten and Buntkowsky, Gerd}}, journal = {{Physical Chemistry Chemical Physics}}, number = {{16}}, pages = {{10697–10712}}, publisher = {{The Royal Society of Chemistry}}, title = {{{Gas phase 1H NMR studies and kinetic modeling of dihydrogen isotope equilibration catalyzed by Ru-nanoparticles under normal conditions: dissociative vs. associative exchange}}}, doi = {{10.1039/C7CP07770J}}, volume = {{20}}, year = {{2018}}, } @article{64010, abstract = {{Seven novel dirhodium coordination polymers (Rh-2-Ln) (n = 1-7) are prepared by employing bitopic ligands to connect dirhodium nodes. The formation of the framework is confirmed by attenuated total reflectance Fourier transform infrared (ATR-FTIR) and H-1 C-13 cross polarization magic angle spinning nuclear magnetic resonance (CP MAS NMR) spectroscopy. Defect sites resulting from incomplete ligand substitution are revealed by F-19 MAS NMR. The random stacking behavior of the frameworks in the obtained solid is analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The Rh-2/O interaction in neighboring layers is investigated by diffuse reflectance ultra-violet visible light (DR-UV-vis) spectroscopy and X-ray photoelectron spectroscopy (XPS). This interaction is relevant to understand the catalytic behavior of various Rh-2-Ln catalysts in the cyclopropanation of styrene with ethyl diazoacetate (EDA). In this context, the structure-reactivity relationship is discussed by taking into consideration both interlayer Rh-2/O interactions and steric effects of side chains.}}, author = {{Liu, J. Q. and Xu, Y. P. and Groszewicz, P. B. and Brodrecht, M. and Fasel, C. and Hofmann, K. and Tan, X. J. and Gutmann, Torsten and Buntkowsky, G.}}, issn = {{2044-4753}}, journal = {{Catalysis Science & Technology}}, keywords = {{Chemistry, asymmetric cyclopropanation, c-h insertion, carbene transformations, carboxylates, catalysts, functionalization, immobilization, metal-organic frameworks, nmr, solid support}}, number = {{20}}, pages = {{5190–5200}}, title = {{{Novel dirhodium coordination polymers: the impact of side chains on cyclopropanation}}}, doi = {{10.1039/c8cy01493k}}, volume = {{8}}, year = {{2018}}, } @article{64014, abstract = {{Many efforts have been made to isolate native nanocrystals from raw materials in the last two decades, such as cellulose nanocrystals (CNCs), but existing methods still suffer from low yields, complicated synthesis processes, and nonuniform sizes of obtained CNCs. This study concerns a facile, self-terminating, and efficient method for the formation of uniform CNCs in high yields during the periodate oxidation process within Pickering emulsions. A biphasic system containing hexane with dissolved hexylamine and an aqueous solution of sodium periodate (NaIO4) was used as the reaction medium. Regulated by hexylamine, owing to its limited solubility in water, the pH value of the aqueous phase was enhanced to around 9.8, leading to the precipitation of sodium orthoperiodate (Na2H3IO6) nanoplates and thus the formation of the initial Pickering emulsions. During the gradual formation of cellulose nanofibers and then CNCs, CNCs were attracted to stabilize the interface of the Pickering emulsions, which prevented further decomposition of CNCs by the oxidizing agent in aqueous suspensions. Thus, this isolation strategy secured the efficient separation of CNCs based on their own particular amphiphilic properties and achieved a high yield of up to 56 wt%.}}, author = {{Liu, P. W. and Pang, B. and Tian, L. and Schafer, T. and Gutmann, Torsten and Liu, H. and Volkert, C. A. and Buntkowsky, G. and Zhang, K.}}, journal = {{ChemSusChem}}, number = {{20}}, pages = {{3581–3585}}, title = {{{Efficient, Self-Terminating Isolation of Cellulose Nanocrystals through Periodate Oxidation in Pickering Emulsions}}}, doi = {{10.1002/cssc.201801678}}, volume = {{11}}, year = {{2018}}, } @article{64000, abstract = {{Surface enhanced solid-state NMR by dynamic nuclear polarization (DNP SENS) enables the characterization of the inner-pore surface functionalization of porous etched ion-track membranes exhibiting low specific surface areas compared to typical SBA- or MCM-type mesoporous silica materials. The membranes were conformally coated with a 5 nm thin SiO2 layer by atomic layer deposition. This layer was subsequently modified by aminopropyl silane linkers that allow further functionalization via the terminal amine group. The results evidence that in principle DNP SENS is a capable tool to analyze more complex porous systems, e.g. bioinspired functional etched ion-track membranes down to the molecular level. These results are relevant also for single nanopore systems, for which a direct analysis of the channel surface functionalization is not feasible by classical characterization methods. The applicability of DNP SENS to complex porous systems requires the optimization of the sample preparation and measurement parameters.}}, author = {{Kumari, B. and John, D. and Hoffmann, P. and Spende, A. and Toimil-Molares, M. E. and Trautmann, C. and Hess, C. and Ruff, P. and Schulze, M. and Stark, R. and Buntkowsky, G. and Andrieu-Brunsen, A. and Gutmann, Torsten}}, issn = {{0942-9352}}, journal = {{Zeitschrift Fur Physikalische Chemie-International Journal of Research in Physical Chemistry & Chemical Physics}}, number = {{7-8}}, pages = {{1173–1186}}, title = {{{Surface Enhanced DNP Assisted Solid-State NMR of Functionatized SiO2 Coated Potycarbonate Membranes}}}, doi = {{10.1515/zpch-2017-1032}}, volume = {{232}}, year = {{2018}}, } @article{63999, abstract = {{The behavior of mixtures of 1-octanol with water with different molar ratios confined inside the mesoporous silica SBA-15 was investigated by a combination of solid-state NMR spectroscopy and molecular dynamics (MD) simulations. Two-dimensional H-1-Si-29 FSLG-HET-COR NMR spectra revealed the orientation of 1-octanol relative to the pore walls. These arrangements are in good agreement with the preferred structures found by MD. In addition, MD simulations also shed light on molecular orientations and interactions in the pore center region, which are not resolvable by solid-state NMR.}}, author = {{Kumari, B. and Brodrecht, M. and Breitzke, H. and Werner, M. and Grunberg, B. and Limbach, H. H. and Forg, S. and Sanjon, E. P. and Drossel, B. and Gutmann, Torsten and Buntkowsky, G.}}, issn = {{1932-7447}}, journal = {{Journal of Physical Chemistry C}}, number = {{34}}, pages = {{19540–19550}}, title = {{{Mixtures of Alcohols and Water confined in Mesoporous Silica: A Combined Solid-State NMR and Molecular Dynamics Simulation Study}}}, doi = {{10.1021/acs.jpcc.8b04745}}, volume = {{122}}, year = {{2018}}, } @article{63978, abstract = {{The colligative property freezing point depression is evaluated as a means for estimating the extent of aggregation for solutions of poly(ethylene oxide) alcohol (C10E6) nonionic surfactant in cyclohexane. Combined with additional measurements of self-diffusion coefficients, it is shown that both unaggregated C10E6 as well as reverse micelles are significantly present for the entire range of measured C10E6 concentration (0.048−2.35 mol kg−1). A change in speciation near 0.2 mol kg−1 is indicated by the results from both freezing point depression and selfdiffusion coefficient measurements. It is shown that average reverse micelle radii and aggregation numbers obtained from the ratio of solvent and C10E6 self-diffusion coefficients are consistent with prior reported results. However, unreasonably small radii for the reverse micelles as well as for the cyclohexane were obtained from analysis of the results by the Stokes−Einstein equation using additional measured solution viscosities. The concentration of reverse micelles and unaggregated C10E6 was calculated from the freezing point depression results using the aggregation numbers obtained from ratio of self-diffusion coefficients. These concentrations indicate that the reverse micelles become smaller in average size and increase in number with increasing temperature without an increase in unaggregated C10E6.}}, author = {{Hoffmann, Markus M. and Bothe, Sarah and Gutmann, Torsten and Buntkowsky, Gerd}}, journal = {{Journal of Physical Chemistry B}}, number = {{18}}, pages = {{4913–4921}}, publisher = {{American Chemical Society}}, title = {{{Combining Freezing Point Depression and Self-Diffusion Data for Characterizing Aggregation}}}, doi = {{10.1021/acs.jpcb.8b03456}}, volume = {{122}}, year = {{2018}}, } @article{63938, author = {{Cao, Yuan and Zhao, Li and Gutmann, Torsten and Xu, Yeping and Dong, Lin and Buntkowsky, Gerd and Gao, Fei}}, issn = {{1932-7447}}, journal = {{Journal of Physical Chemistry C}}, number = {{35}}, pages = {{20402–20409}}, publisher = {{American Chemical Society}}, title = {{{Getting Insights into the Influence of Crystal Plane Effect of Shaped Ceria on Its Catalytic Performances}}}, doi = {{10.1021/acs.jpcc.8b06138}}, volume = {{122}}, year = {{2018}}, } @article{63940, author = {{Dagys, Laurynas and Klimavicius, Vytautas and Gutmann, Torsten and Buntkowsky, Gerd and Balevicius, Vytautas}}, journal = {{Journal of Physical Chemistry A}}, number = {{45}}, pages = {{8938–8947}}, publisher = {{American Chemical Society}}, title = {{{Quasi-Equilibria and Polarization Transfer Between Adjacent and Remote Spins: 1H–13C CP MAS Kinetics in Glycine}}}, doi = {{10.1021/acs.jpca.8b09036}}, volume = {{122}}, year = {{2018}}, } @article{63926, abstract = {{Synthesis of novel trityl-nitroxyl biradicals and their performance as polarization agents in DNP-enhanced solid-state MAS NMR spectroscopy is presented. Signal enhancements in H-1, H-1 -{\textgreater} C-13 CP MAS, and C-13 MAS experiments obtained with these radicals dissolved in 1,1,2,2-tetrachloroethane (TCE) solution are compared with the enhancements obtained from TCE solutions of binitroxyl radicals. The signal enhancements are correlated with the distance between the radical centers of the biradicals, as determined by theoretical structure calculations. Some of the biradical TCE solutions display direct-channel resonances in C-13 MAS experiments as well as indirect channel resonances induced via the proton spin reservoir. Differential scanning calorimetry reveals that only these solutions do not form any solid crystalline phases upon rapid cooling, suggesting that molecular motions needed for polarization transfer from radicals to C-13 via the proton spin reservoir remain active at the experimental low temperatures of nominal 120 K. DNP magnetic field sweep enhancement profiles for selected new biradicals are presented as well. These indicate that the DNP transfer is dominated by the cross-effect mechanism.}}, author = {{Bothe, S. and Nowag, J. and Klimavicius, V. and Hoffmann, M. and Troitskaya, T. I. and Amosov, E. V. and Tormyshev, V. M. and Kirilyuk, I. and Taratayko, A. and Kuzhelev, A. and Parkhomenko, D. and Bagryanskaya, E. and Gutmann, Torsten and Buntkowsky, G.}}, issn = {{1932-7447}}, journal = {{Journal of Physical Chemistry C}}, number = {{21}}, pages = {{11422–11432}}, title = {{{Novel Biradicals for Direct Excitation Highfield Dynamic Nuclear Polarization}}}, doi = {{10.1021/acs.jpcc.8b02570}}, volume = {{122}}, year = {{2018}}, } @article{63928, abstract = {{A series of novel functionalized mesoporous silica-based materials with well-defined pore diameters, surface functionalization and surface morphology is synthesized by co-condensation or grafting techniques and characterized by solid-state NMR spectroscopy, DNP enhanced solid state-NMR and thermodynamic techniques. These materials are employed as host-systems for small-guest molecules like water, small alcohols, carbonic acids, small aromatic molecules, binary mixtures and others. The phase-behavior of these confined guests is studied by combinations of one dimensional solid-state NMR techniques (H-1 MAS, H-2-line shape analysis, C-13 CPMAS) and two-dimensional correlation experiments like H-1-Si-29- solid-state HETCOR.}}, author = {{Brodrecht, M. and Kumari, B. and Breitzke, H. and Gutmann, Torsten and Buntkowsky, G.}}, issn = {{0942-9352}}, journal = {{Zeitschrift Fur Physikalische Chemie-International Journal of Research in Physical Chemistry & Chemical Physics}}, number = {{7-8}}, pages = {{1127–1146}}, title = {{{Chemically Modified Silica Materials as Model Systems for the Characterization of Water-Surface Interactions}}}, doi = {{10.1515/zpch-2017-1059}}, volume = {{232}}, year = {{2018}}, } @article{63929, author = {{Brodrecht, Martin and Breitzke, Hergen and Gutmann, Torsten and Buntkowsky, Gerd}}, journal = {{Chemistry A European Journal}}, number = {{67}}, pages = {{17814–17822}}, title = {{{Biofunctionalization of Nano Channels by Direct In-Pore Solid-Phase Peptide Synthesis}}}, doi = {{10.1002/chem.201804065}}, volume = {{24}}, year = {{2018}}, } @article{63924, abstract = {{In a systematic study on the synthesis of aluminophosphates (AlPOs) under ionothermal conditions, initially using 1-butyl-3-methylimidazolium bromide ([C4mim]Br) as ionic liquid solvent and structure-directing agent, the effect of the reaction conditions (i.e. molar P/Al, F/Al and ionic liquid/Al ratios, alternative fluoride sources, influence of the ionic liquid’s cation or anion, temperature, reaction time) on the framework type was studied in detail. In [C4mim]Br, the formation of the more thermodynamically stable AEL framework type proceeds via AFI. The framework type can be changed by choosing another anion or cation of the ionic liquid. Hence, the successful ionothermal synthesis of the AFI framework AlPO is reported by using either N-ethylpyridinium bromide ([C2py]Br) or 1-butyl-3-methylimidazolium chloride ([C4mim]Cl). The mineraliser [Me4N]F, rather than HF, has been used for the first time as an alternative fluoride source in ionothermal synthesis, which can also affect the framework type. Hence, a very efficient synthesis of the LTA framework type is reported in [C4mim]Br using [Me4N]F. Ab initio molecular dynamics (AIMD) studies showed that the anion bridges between the aluminium atoms of the framework and the cation. The interaction is more favoured in the presence of the bromide than the chloride, which may be a clue to the question why the AEL framework is not formed in the chloride-based ionic liquid. This study opens several routes to pursue in the future as numerous ionic liquids are available which can be used in ionothermal synthesis.}}, author = {{Azim, Muhammad Mohsin and Pensado, Alfonso and Kirchner, Barbara and Gutmann, Torsten and Groszewicz, Pedro B. and Buntkowsky, Gerd and Stark, Annegret}}, journal = {{Microporous and Mesoporous Materials}}, keywords = {{Aluminophosphates, Ionic liquids, Ionothermal synthesis, Microporous materials, Zeolite analogous}}, pages = {{204–213}}, title = {{{Ionothermal synthesis of crystalline microporous aluminophosphates: Systematic study on the conditions affecting the framework type}}}, doi = {{10.1016/j.micromeso.2018.02.053}}, volume = {{266}}, year = {{2018}}, } @book{64156, author = {{Gutmann, Torsten and Buntkowsky, Gerd and Webb, Graham}}, isbn = {{978-3-319-28275-6}}, publisher = {{Springer International Publishing}}, title = {{{Modern Magnetic Resonance}}}, year = {{2017}}, } @article{64053, abstract = {{The utilization and preparation of functional hybrid films for optical sensing applications and membranes is of utmost importance. In this work, we report the convenient and scalable preparation of self-crosslinking particle-based films derived by directed self-assembly of alkoxysilane-based cross-linkers as part of a core-shell particle architecture. The synthesis of well-designed monodisperse core-shell particles by emulsion polymerization is the basic prerequisite for subsequent particle processing via the melt-shear organization technique. In more detail, the core particles consist of polystyrene (PS) or poly(methyl methacrylate) (PMMA), while the comparably soft particle shell consists of poly(ethyl acrylate) (PEA) and different alkoxysilane-based poly(methacrylate)s. For hybrid film formation and convenient self-cross-linking, different alkyl groups at the siloxane moieties were investigated in detail by solid-state Magic-Angle Spinning Nuclear Magnetic Resonance (MAS, NMR) spectroscopy revealing different crosslinking capabilities, which strongly influence the properties of the core or shell particle films with respect to transparency and iridescent reflection colors. Furthermore, solid-state NMR spectroscopy and investigation of the thermal properties by differential scanning calorimetry (DSC) measurements allow for insights into the cross-linking capabilities prior to and after synthesis, as well as after the thermally and pressure-induced processing steps. Subsequently, free-standing and self-crosslinked particle-based films featuring excellent particle order are obtained by application of the melt-shear organization technique, as shown by microscopy (TEM, SEM).}}, author = {{Vowinkel, S. and Paul, S. and Gutmann, Torsten and Gallei, M.}}, issn = {{2079-4991}}, journal = {{Nanomaterials}}, keywords = {{Materials Science, Science & Technology - Other Topics, solid-state nmr, spectroscopy, catalysts, colloidal crystals, colloids, cross-linking, elastomeric opal films, emulsion polymerization, gamma-methacryloxypropyltrimethoxysilane, hybrid films, melt-shear organization, nanoparticles, particle, photons, polymers, processing, self-assembly, transition}}, number = {{11}}, pages = {{390}}, title = {{{Free-Standing and Self-Crosslinkable Hybrid Films by Core-Shell Particle Design and Processing}}}, doi = {{10.3390/nano7110390}}, volume = {{7}}, year = {{2017}}, } @article{64057, abstract = {{Self-assembly of nanoparticles (NPs) forming unique structures has been investigated extensively over the past few years. However, many self-assembled structures by NPs are irreversible, because they are generally constructed using their suspensions. It is still challenging for NPs to reversibly self-assemble in dry state, let alone of polymeric NPs with general sizes of hundreds of nm. Herein, this study reports a new reversible self-assembly phenomenon of NPs in dry state, forming thermoreversible strip-like supermolecular structures. These novel NPs of around 150 nm are perfluorinated surface-undecenoated cellulose nanoparticles (FSU-CNPs) with a core-coronas structure. The thermoreversible self-assembled structure is formed after drying in the air at the interface between FSU-CNP films and Teflon substrates. Remarkably, the formation and dissociation of this assembled structure are accompanied by a reversible conversion of the surface hydrophobicity, film transparency, and anisotropic properties. These findings show novel feasibility of reversible self-assembly of NPs in dry state, and thereby expand our knowledge of self-assembly phenomenon.}}, author = {{Wang, Yonggui and Groszewicz, Pedro B. and Rosenfeldt, Sabine and Schmidt, Hendrik and Volkert, Cynthia A. and Vana, Philipp and Gutmann, Torsten and Buntkowsky, Gerd and Zhang, Kai}}, journal = {{Advanced Materials}}, keywords = {{nanoparticles, self-assembly, cellulose, core-coronas structure, thermoreversible}}, pages = {{1702473}}, title = {{{Thermoreversible Self-Assembly of Perfluorinated Core-Coronas Cellulose-Nanoparticles in Dry State}}}, doi = {{10.1002/adma.201702473}}, year = {{2017}}, }