--- _id: '64002' abstract: - lang: eng text: The production of formaldehyde on industrial scale requires huge amounts of energy due to the involvement of reforming processes in combination with the demand in the megaton scale. Hence, a direct route for the transformation of (bio)methane to formaldehyde would decrease costs and puts less pressure on the environment. Herein, we report on the use of zinc modified silicas as possible support materials for vanadium catalysts and the resulting consequences for the performance in the selective oxidation of methane to formaldehyde. After optimization of the Zn content and reaction conditions, a remarkably high space-time yield of 12.4 kgCH2O·kgcat−1·h−1 was achieved. As a result of the extensive characterization by means of UV–vis, Raman, XANES and NMR spectroscopy it was found that vanadium is in the vicinity of highly dispersed zinc atoms which promote the formation of active vanadium species as supposed by theoretical calculations. This work presents a further step of catalyst development towards direct industrial methane conversion which may help to overcome current limitations in the future. author: - first_name: Benny full_name: Kunkel, Benny last_name: Kunkel - first_name: Dominik full_name: Seeburg, Dominik last_name: Seeburg - first_name: Anke full_name: Kabelitz, Anke last_name: Kabelitz - first_name: Steffen full_name: Witte, Steffen last_name: Witte - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Hergen full_name: Breitzke, Hergen last_name: Breitzke - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky - first_name: Ana Guilherme full_name: Buzanich, Ana Guilherme last_name: Buzanich - first_name: Sebastian full_name: Wohlrab, Sebastian last_name: Wohlrab citation: ama: Kunkel B, Seeburg D, Kabelitz A, et al. Highly productive V/Zn-SiO2 catalysts for the selective oxidation of methane. Catalysis Today. 2024;432:114643. doi:10.1016/j.cattod.2024.114643 apa: Kunkel, B., Seeburg, D., Kabelitz, A., Witte, S., Gutmann, T., Breitzke, H., Buntkowsky, G., Buzanich, A. G., & Wohlrab, S. (2024). Highly productive V/Zn-SiO2 catalysts for the selective oxidation of methane. Catalysis Today, 432, 114643. https://doi.org/10.1016/j.cattod.2024.114643 bibtex: '@article{Kunkel_Seeburg_Kabelitz_Witte_Gutmann_Breitzke_Buntkowsky_Buzanich_Wohlrab_2024, title={Highly productive V/Zn-SiO2 catalysts for the selective oxidation of methane}, volume={432}, DOI={10.1016/j.cattod.2024.114643}, journal={Catalysis Today}, author={Kunkel, Benny and Seeburg, Dominik and Kabelitz, Anke and Witte, Steffen and Gutmann, Torsten and Breitzke, Hergen and Buntkowsky, Gerd and Buzanich, Ana Guilherme and Wohlrab, Sebastian}, year={2024}, pages={114643} }' chicago: 'Kunkel, Benny, Dominik Seeburg, Anke Kabelitz, Steffen Witte, Torsten Gutmann, Hergen Breitzke, Gerd Buntkowsky, Ana Guilherme Buzanich, and Sebastian Wohlrab. “Highly Productive V/Zn-SiO2 Catalysts for the Selective Oxidation of Methane.” Catalysis Today 432 (2024): 114643. https://doi.org/10.1016/j.cattod.2024.114643.' ieee: 'B. Kunkel et al., “Highly productive V/Zn-SiO2 catalysts for the selective oxidation of methane,” Catalysis Today, vol. 432, p. 114643, 2024, doi: 10.1016/j.cattod.2024.114643.' mla: Kunkel, Benny, et al. “Highly Productive V/Zn-SiO2 Catalysts for the Selective Oxidation of Methane.” Catalysis Today, vol. 432, 2024, p. 114643, doi:10.1016/j.cattod.2024.114643. short: B. Kunkel, D. Seeburg, A. Kabelitz, S. Witte, T. Gutmann, H. Breitzke, G. Buntkowsky, A.G. Buzanich, S. Wohlrab, Catalysis Today 432 (2024) 114643. date_created: 2026-02-07T15:53:56Z date_updated: 2026-02-17T16:15:41Z doi: 10.1016/j.cattod.2024.114643 extern: '1' intvolume: ' 432' keyword: - Formaldehyde - Local coordination - SBA-15 - Vanadium oxo species - XANES - Zinc doped silica language: - iso: eng page: '114643' publication: Catalysis Today status: public title: Highly productive V/Zn-SiO2 catalysts for the selective oxidation of methane type: journal_article user_id: '100715' volume: 432 year: '2024' ... --- _id: '63989' abstract: - lang: eng text: We introduce the first mechanochemical cyclotrimerization of nitriles, a facile strategy for synthesizing triazine-containing molecules and materials, overcoming challenges related to carbonization and solubility. Conducting this solid-state approach in a mixer ball mill with 4-Methylbenzonitrile, we synthesize Tris(4-methylphenyl)-1,3,5-triazine quantitatively in as little as 90 minutes. Just as fast, this mechanochemical method facilitates the synthesis of the covalent triazine framework CTF-1 using 1,4 Dicyanobenzene. Material characterization confirms its porous (650 m2 g-1) and crystalline nature. Adjusting the induced mechanical energy allows control over the obtained stacking conformation of the resulting CTFs - from a staggered AB arrangement to an eclipsed AA stacking conformation. Finally, a substrate scope demonstrates the versatility of this approach, successfully yielding various CTFs. This work presents, for the first time, the mechanochemical cyclotrimerization of nitriles. Utilizing Trifluoromethanesulfonic acid and a ball mill, both small molecules and large organic frameworks could be obtained. Screening the reaction of 1,4-Dicyanobenzene by various parameters, such as reaction time, frequency, or temperature, significant impacts on the porosity of the polymer and its crystallinity were revealed. image author: - first_name: S. full_name: Hutsch, S. last_name: Hutsch - first_name: A. full_name: Leonard, A. last_name: Leonard - first_name: S. full_name: Grätz, S. last_name: Grätz - first_name: M. V. full_name: Höfler, M. V. last_name: Höfler - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: L. full_name: Borchardt, L. last_name: Borchardt citation: ama: 'Hutsch S, Leonard A, Grätz S, Höfler MV, Gutmann T, Borchardt L. Mechanochemical Cyclotrimerization: A Versatile Tool to Covalent Organic Frameworks with Tunable Stacking Mode. Angewandte Chemie-International Edition. Published online 2024. doi:10.1002/anie.202403649' apa: 'Hutsch, S., Leonard, A., Grätz, S., Höfler, M. V., Gutmann, T., & Borchardt, L. (2024). Mechanochemical Cyclotrimerization: A Versatile Tool to Covalent Organic Frameworks with Tunable Stacking Mode. Angewandte Chemie-International Edition. https://doi.org/10.1002/anie.202403649' bibtex: '@article{Hutsch_Leonard_Grätz_Höfler_Gutmann_Borchardt_2024, title={Mechanochemical Cyclotrimerization: A Versatile Tool to Covalent Organic Frameworks with Tunable Stacking Mode}, DOI={10.1002/anie.202403649}, journal={Angewandte Chemie-International Edition}, author={Hutsch, S. and Leonard, A. and Grätz, S. and Höfler, M. V. and Gutmann, Torsten and Borchardt, L.}, year={2024} }' chicago: 'Hutsch, S., A. Leonard, S. Grätz, M. V. Höfler, Torsten Gutmann, and L. Borchardt. “Mechanochemical Cyclotrimerization: A Versatile Tool to Covalent Organic Frameworks with Tunable Stacking Mode.” Angewandte Chemie-International Edition, 2024. https://doi.org/10.1002/anie.202403649.' ieee: 'S. Hutsch, A. Leonard, S. Grätz, M. V. Höfler, T. Gutmann, and L. Borchardt, “Mechanochemical Cyclotrimerization: A Versatile Tool to Covalent Organic Frameworks with Tunable Stacking Mode,” Angewandte Chemie-International Edition, 2024, doi: 10.1002/anie.202403649.' mla: 'Hutsch, S., et al. “Mechanochemical Cyclotrimerization: A Versatile Tool to Covalent Organic Frameworks with Tunable Stacking Mode.” Angewandte Chemie-International Edition, 2024, doi:10.1002/anie.202403649.' short: S. Hutsch, A. Leonard, S. Grätz, M.V. Höfler, T. Gutmann, L. Borchardt, Angewandte Chemie-International Edition (2024). date_created: 2026-02-07T15:46:50Z date_updated: 2026-02-17T16:16:38Z doi: 10.1002/anie.202403649 extern: '1' language: - iso: eng publication: Angewandte Chemie-International Edition publication_identifier: issn: - 1433-7851 status: public title: 'Mechanochemical Cyclotrimerization: A Versatile Tool to Covalent Organic Frameworks with Tunable Stacking Mode' type: journal_article user_id: '100715' year: '2024' ... --- _id: '63980' abstract: - lang: eng text: Density, viscosity, and self-diffusion coefficients are reported for octan-1-ol and the related ether-alcohols 2-pentoxy-ethan-1-ol, 3-butoxypropan-1-ol, 4-propoxybutan-1-ol, 5-ethoxypentan-1-ol, and 6-methoxyhexan-1-ol covering temperature ranges from 298.15 to 359.15 K. These new data reveal structure–property relationships affected by the presence and the position of the ether moiety in the molecular structure of the ether-alcohols. Compared to octan-1-ol, the presence of the ether moiety causes an increase in intermolecular hydrogen bonding interactions, resulting in higher densities. The increase in density is less pronounced for those ether-octanols that engage in intramolecular hydrogen bonding. As for the effects of the ether moiety on the dynamics, these are generally faster for the ether-alcohols compared to octan-1-ol, suggesting that hydrogen bonding between ether oxygen and hydroxy hydrogen is weaker compared to hydrogen bonding between two hydroxy groups. The activation energies obtained from an Arrhenius analysis are higher for translational motion than for momentum transfer for all alcohols. There are additional finer details across the ether alcohols for these activation barriers. These differences cancel out for the mathematical product of self-diffusion coefficient and viscosity (Dη). The effect of water impurities on the studied properties was also investigated and found to lead to small increases in densities for all alcohols. Viscosities decrease for octan-1-ol and 2-pentoxyethan-1-ol but increase for the other ether-alcohols that can engage in intramolecular hydrogen bonding. Density, viscosity, and self-diffusion coefficients are reported for octan-1-ol and the related ether-alcohols 2-pentoxy-ethan-1-ol, 3-butoxypropan-1-ol, 4-propoxybutan-1-ol, 5-ethoxypentan-1-ol, and 6-methoxyhexan-1-ol covering temperature ranges from 298.15 to 359.15 K. These new data reveal structure–property relationships affected by the presence and the position of the ether moiety in the molecular structure of the ether-alcohols. Compared to octan-1-ol, the presence of the ether moiety causes an increase in intermolecular hydrogen bonding interactions, resulting in higher densities. The increase in density is less pronounced for those ether-octanols that engage in intramolecular hydrogen bonding. As for the effects of the ether moiety on the dynamics, these are generally faster for the ether-alcohols compared to octan-1-ol, suggesting that hydrogen bonding between ether oxygen and hydroxy hydrogen is weaker compared to hydrogen bonding between two hydroxy groups. The activation energies obtained from an Arrhenius analysis are higher for translational motion than for momentum transfer for all alcohols. There are additional finer details across the ether alcohols for these activation barriers. These differences cancel out for the mathematical product of self-diffusion coefficient and viscosity (Dη). The effect of water impurities on the studied properties was also investigated and found to lead to small increases in densities for all alcohols. Viscosities decrease for octan-1-ol and 2-pentoxyethan-1-ol but increase for the other ether-alcohols that can engage in intramolecular hydrogen bonding. author: - first_name: Markus M. full_name: Hoffmann, Markus M. last_name: Hoffmann - first_name: Anthony A. full_name: Gonzalez, Anthony A. last_name: Gonzalez - first_name: Mandy T. full_name: Huynh, Mandy T. last_name: Huynh - first_name: Kashane K. full_name: Miller, Kashane K. last_name: Miller - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky citation: ama: Hoffmann MM, Gonzalez AA, Huynh MT, Miller KK, Gutmann T, Buntkowsky G. Densities, Viscosities, and Self-Diffusion Coefficients of Octan-1-ol and Related Ether-Alcohols. Journal of Chemical & Engineering Data. 2024;69(8):2688–2699. doi:10.1021/acs.jced.4c00195 apa: Hoffmann, M. M., Gonzalez, A. A., Huynh, M. T., Miller, K. K., Gutmann, T., & Buntkowsky, G. (2024). Densities, Viscosities, and Self-Diffusion Coefficients of Octan-1-ol and Related Ether-Alcohols. Journal of Chemical & Engineering Data, 69(8), 2688–2699. https://doi.org/10.1021/acs.jced.4c00195 bibtex: '@article{Hoffmann_Gonzalez_Huynh_Miller_Gutmann_Buntkowsky_2024, title={Densities, Viscosities, and Self-Diffusion Coefficients of Octan-1-ol and Related Ether-Alcohols}, volume={69}, DOI={10.1021/acs.jced.4c00195}, number={8}, journal={Journal of Chemical & Engineering Data}, publisher={American Chemical Society}, author={Hoffmann, Markus M. and Gonzalez, Anthony A. and Huynh, Mandy T. and Miller, Kashane K. and Gutmann, Torsten and Buntkowsky, Gerd}, year={2024}, pages={2688–2699} }' chicago: 'Hoffmann, Markus M., Anthony A. Gonzalez, Mandy T. Huynh, Kashane K. Miller, Torsten Gutmann, and Gerd Buntkowsky. “Densities, Viscosities, and Self-Diffusion Coefficients of Octan-1-Ol and Related Ether-Alcohols.” Journal of Chemical & Engineering Data 69, no. 8 (2024): 2688–2699. https://doi.org/10.1021/acs.jced.4c00195.' ieee: 'M. M. Hoffmann, A. A. Gonzalez, M. T. Huynh, K. K. Miller, T. Gutmann, and G. Buntkowsky, “Densities, Viscosities, and Self-Diffusion Coefficients of Octan-1-ol and Related Ether-Alcohols,” Journal of Chemical & Engineering Data, vol. 69, no. 8, pp. 2688–2699, 2024, doi: 10.1021/acs.jced.4c00195.' mla: Hoffmann, Markus M., et al. “Densities, Viscosities, and Self-Diffusion Coefficients of Octan-1-Ol and Related Ether-Alcohols.” Journal of Chemical & Engineering Data, vol. 69, no. 8, American Chemical Society, 2024, pp. 2688–2699, doi:10.1021/acs.jced.4c00195. short: M.M. Hoffmann, A.A. Gonzalez, M.T. Huynh, K.K. Miller, T. Gutmann, G. Buntkowsky, Journal of Chemical & Engineering Data 69 (2024) 2688–2699. date_created: 2026-02-07T15:43:54Z date_updated: 2026-02-17T16:16:59Z doi: 10.1021/acs.jced.4c00195 extern: '1' intvolume: ' 69' issue: '8' language: - iso: eng page: 2688–2699 publication: Journal of Chemical & Engineering Data publication_identifier: issn: - 0021-9568 publisher: American Chemical Society status: public title: Densities, Viscosities, and Self-Diffusion Coefficients of Octan-1-ol and Related Ether-Alcohols type: journal_article user_id: '100715' volume: 69 year: '2024' ... --- _id: '63988' abstract: - lang: eng text: This concept summarizes recent advances in development and application of DNP enhanced multinuclear solid-state NMR to study the molecular structure and surface functionalization of cellulose and paper-based materials. Moreover, a novel application is presented where DNP enhanced 13C and 15N solid-state NMR is used to identify structure moieties formed by cross-linking of hydroxypropyl cellulose. Given these two aspects of this concept-type of article, we thus combine both, a review on recent findings already published and unpublished recent data that complement the existing knowledge in the field of characterization of functional lignocellulosic materials by DNP enhanced solid-state NMR. author: - first_name: Mark V. full_name: Höfler, Mark V. last_name: Höfler - first_name: Jonas full_name: Lins, Jonas last_name: Lins - first_name: David full_name: Seelinger, David last_name: Seelinger - first_name: Lukas full_name: Pachernegg, Lukas last_name: Pachernegg - first_name: Timmy full_name: Schäfer, Timmy last_name: Schäfer - first_name: Stefan full_name: Spirk, Stefan last_name: Spirk - first_name: Markus full_name: Biesalski, Markus last_name: Biesalski - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann citation: ama: Höfler MV, Lins J, Seelinger D, et al. DNP enhanced solid-state NMR – A powerful tool to address the surface functionalization of cellulose/paper derived materials. Journal of Magnetic Resonance Open. 2024;21:100163. doi:10.1016/j.jmro.2024.100163 apa: Höfler, M. V., Lins, J., Seelinger, D., Pachernegg, L., Schäfer, T., Spirk, S., Biesalski, M., & Gutmann, T. (2024). DNP enhanced solid-state NMR – A powerful tool to address the surface functionalization of cellulose/paper derived materials. Journal of Magnetic Resonance Open, 21, 100163. https://doi.org/10.1016/j.jmro.2024.100163 bibtex: '@article{Höfler_Lins_Seelinger_Pachernegg_Schäfer_Spirk_Biesalski_Gutmann_2024, title={DNP enhanced solid-state NMR – A powerful tool to address the surface functionalization of cellulose/paper derived materials}, volume={21}, DOI={10.1016/j.jmro.2024.100163}, journal={Journal of Magnetic Resonance Open}, author={Höfler, Mark V. and Lins, Jonas and Seelinger, David and Pachernegg, Lukas and Schäfer, Timmy and Spirk, Stefan and Biesalski, Markus and Gutmann, Torsten}, year={2024}, pages={100163} }' chicago: 'Höfler, Mark V., Jonas Lins, David Seelinger, Lukas Pachernegg, Timmy Schäfer, Stefan Spirk, Markus Biesalski, and Torsten Gutmann. “DNP Enhanced Solid-State NMR – A Powerful Tool to Address the Surface Functionalization of Cellulose/Paper Derived Materials.” Journal of Magnetic Resonance Open 21 (2024): 100163. https://doi.org/10.1016/j.jmro.2024.100163.' ieee: 'M. V. Höfler et al., “DNP enhanced solid-state NMR – A powerful tool to address the surface functionalization of cellulose/paper derived materials,” Journal of Magnetic Resonance Open, vol. 21, p. 100163, 2024, doi: 10.1016/j.jmro.2024.100163.' mla: Höfler, Mark V., et al. “DNP Enhanced Solid-State NMR – A Powerful Tool to Address the Surface Functionalization of Cellulose/Paper Derived Materials.” Journal of Magnetic Resonance Open, vol. 21, 2024, p. 100163, doi:10.1016/j.jmro.2024.100163. short: M.V. Höfler, J. Lins, D. Seelinger, L. Pachernegg, T. Schäfer, S. Spirk, M. Biesalski, T. Gutmann, Journal of Magnetic Resonance Open 21 (2024) 100163. date_created: 2026-02-07T15:46:32Z date_updated: 2026-02-17T16:16:40Z doi: 10.1016/j.jmro.2024.100163 extern: '1' intvolume: ' 21' keyword: - solid-state nmr - dynamic nuclear polarization - Hydroxypropyl cellulose - Selective enhancement - Spin labelling language: - iso: eng page: '100163' publication: Journal of Magnetic Resonance Open status: public title: DNP enhanced solid-state NMR – A powerful tool to address the surface functionalization of cellulose/paper derived materials type: journal_article user_id: '100715' volume: 21 year: '2024' ... --- _id: '63974' abstract: - lang: eng text: A versatile strategy for synthesizing tailored peptide based biradicals is presented. By labeling the protected amino acid hydroxyproline with PROXYL via the OH functionality and using this building block in solid phase peptide synthesis (SPPS), the obtained peptides become polarization agents for DNP enhanced solid-state NMR in biotolerant media. To analyze the effect of the radical position on the enhancement factor, three different biradicals are synthesized. The PROXYL spin-label is inserted in a collagen inspired artificial peptide sequence by binding through the OH group of the hydroxyproline moieties at specific position in the chain. This labeling strategy is universally applicable for any hydroxyproline position in a peptide sequence since solid-phase peptide synthesis is used to insert the building block. High performance liquid chromatography (HPLC) and mass spectrometry (MS) analyses show the successful introduction of the spin label in the peptide chain and electron paramagnetic resonance (EPR) spectroscopy confirms its activity. Dynamic nuclear polarization (DNP) enhanced solid-state nuclear magnetic resonance (NMR) experiments performed on frozen aqueous glycerol-d8 solutions containing these peptide radicals show significantly higher enhancement factors of up to 45 in 1H→13C cross polarization magic angle spinning (CP MAS) experiments compared to an analogous mono-radical peptide including this building block (ε ≈ 14). Compared to commercial biradicals such as AMUPol for which enhancement factors {\textgreater} 100 have been obtained in the past and which have been optimized in their structure, the obtained enhancement up to 45 for our biradicals presents a significant progress in radical design. author: - first_name: Kevin full_name: Herr, Kevin last_name: Herr - first_name: Mark V. full_name: Höfler, Mark V. last_name: Höfler - first_name: Henrike full_name: Heise, Henrike last_name: Heise - first_name: Fabien full_name: Aussenac, Fabien last_name: Aussenac - first_name: Felix full_name: Kornemann, Felix last_name: Kornemann - first_name: David full_name: Rosenberger, David last_name: Rosenberger - first_name: Martin full_name: Brodrecht, Martin last_name: Brodrecht - first_name: Marcos full_name: Oliveira, Marcos last_name: Oliveira - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann citation: ama: Herr K, Höfler MV, Heise H, et al. Biradicals based on PROXYL containing building blocks for efficient dynamic nuclear polarization in biotolerant media. Journal of Magnetic Resonance Open. 2024;20:100152. doi:10.1016/j.jmro.2024.100152 apa: Herr, K., Höfler, M. V., Heise, H., Aussenac, F., Kornemann, F., Rosenberger, D., Brodrecht, M., Oliveira, M., Buntkowsky, G., & Gutmann, T. (2024). Biradicals based on PROXYL containing building blocks for efficient dynamic nuclear polarization in biotolerant media. Journal of Magnetic Resonance Open, 20, 100152. https://doi.org/10.1016/j.jmro.2024.100152 bibtex: '@article{Herr_Höfler_Heise_Aussenac_Kornemann_Rosenberger_Brodrecht_Oliveira_Buntkowsky_Gutmann_2024, title={Biradicals based on PROXYL containing building blocks for efficient dynamic nuclear polarization in biotolerant media}, volume={20}, DOI={10.1016/j.jmro.2024.100152}, journal={Journal of Magnetic Resonance Open}, author={Herr, Kevin and Höfler, Mark V. and Heise, Henrike and Aussenac, Fabien and Kornemann, Felix and Rosenberger, David and Brodrecht, Martin and Oliveira, Marcos and Buntkowsky, Gerd and Gutmann, Torsten}, year={2024}, pages={100152} }' chicago: 'Herr, Kevin, Mark V. Höfler, Henrike Heise, Fabien Aussenac, Felix Kornemann, David Rosenberger, Martin Brodrecht, Marcos Oliveira, Gerd Buntkowsky, and Torsten Gutmann. “Biradicals Based on PROXYL Containing Building Blocks for Efficient Dynamic Nuclear Polarization in Biotolerant Media.” Journal of Magnetic Resonance Open 20 (2024): 100152. https://doi.org/10.1016/j.jmro.2024.100152.' ieee: 'K. Herr et al., “Biradicals based on PROXYL containing building blocks for efficient dynamic nuclear polarization in biotolerant media,” Journal of Magnetic Resonance Open, vol. 20, p. 100152, 2024, doi: 10.1016/j.jmro.2024.100152.' mla: Herr, Kevin, et al. “Biradicals Based on PROXYL Containing Building Blocks for Efficient Dynamic Nuclear Polarization in Biotolerant Media.” Journal of Magnetic Resonance Open, vol. 20, 2024, p. 100152, doi:10.1016/j.jmro.2024.100152. short: K. Herr, M.V. Höfler, H. Heise, F. Aussenac, F. Kornemann, D. Rosenberger, M. Brodrecht, M. Oliveira, G. Buntkowsky, T. Gutmann, Journal of Magnetic Resonance Open 20 (2024) 100152. date_created: 2026-02-07T15:42:00Z date_updated: 2026-02-17T16:17:22Z doi: 10.1016/j.jmro.2024.100152 extern: '1' intvolume: ' 20' keyword: - solid-state nmr - dynamic nuclear polarization - peptides - Biradicals - Spin labeling language: - iso: eng page: '100152' publication: Journal of Magnetic Resonance Open status: public title: Biradicals based on PROXYL containing building blocks for efficient dynamic nuclear polarization in biotolerant media type: journal_article user_id: '100715' volume: 20 year: '2024' ... --- _id: '63975' abstract: - lang: eng text: In this contribution, we report on the TEMPO-mediated oxidation of pulp fibers used in the general context of papermaking and for the future design of tailor-made paper in advanced applications. We focus in our studies on properties of TEMPO-oxidized pulp fibers to explain the characteristics of the paper made thereof. 13C solid-state NMR analysis reveals that in particular amorphous regions of the fibers are being chemically oxidized, while at the same time the crystalline regions of the fibers are not significantly affected. Investigation of the fiber morphology before and after oxidation shows that the fiber length is not changed, yet the fibers do exhibit an increase in width if in contact with water, which is attributed to an increase in fiber swelling. In addition, fibrillation decreases due to the oxidative removal of loosely bound fines and fibrils, rendering the surface of the resulting oxidized fibers much smoother in comparison to the original fibers. Finally, we observe that both, dry and wet tensile strengths are also higher for paper made of oxidized fibers, most likely due to cross linkable aldehyde groups formed during oxidation (i.e. hemiacetal bond formation in the sheet during thermal drying). Our results of the oxidation of paper fibers thus offer a systematic study helpful for the design of tailor-made paper useful in several applications where a fiber-modification with fiber-immobilized functional motifs is crucial, such as for example in paper-based microfluidic sensors (µPADs) or lab-on a chip-devices. author: - first_name: Laura M. full_name: Hillscher, Laura M. last_name: Hillscher - first_name: Mark V. full_name: Höfler, Mark V. last_name: Höfler - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Cassia full_name: Lux, Cassia last_name: Lux - first_name: K. Uta full_name: Clerkin, K. Uta last_name: Clerkin - first_name: Gerhard full_name: Schwall, Gerhard last_name: Schwall - first_name: Klaus full_name: Villforth, Klaus last_name: Villforth - first_name: Samuel full_name: Schabel, Samuel last_name: Schabel - first_name: Markus full_name: Biesalski, Markus last_name: Biesalski citation: ama: Hillscher LM, Höfler MV, Gutmann T, et al. Influence of TEMPO-oxidation on pulp fiber chemistry, morphology and mechanical paper sheet properties. Cellulose. 2024;31(5):3067–3082. doi:10.1007/s10570-024-05748-5 apa: Hillscher, L. M., Höfler, M. V., Gutmann, T., Lux, C., Clerkin, K. U., Schwall, G., Villforth, K., Schabel, S., & Biesalski, M. (2024). Influence of TEMPO-oxidation on pulp fiber chemistry, morphology and mechanical paper sheet properties. Cellulose, 31(5), 3067–3082. https://doi.org/10.1007/s10570-024-05748-5 bibtex: '@article{Hillscher_Höfler_Gutmann_Lux_Clerkin_Schwall_Villforth_Schabel_Biesalski_2024, title={Influence of TEMPO-oxidation on pulp fiber chemistry, morphology and mechanical paper sheet properties}, volume={31}, DOI={10.1007/s10570-024-05748-5}, number={5}, journal={Cellulose}, author={Hillscher, Laura M. and Höfler, Mark V. and Gutmann, Torsten and Lux, Cassia and Clerkin, K. Uta and Schwall, Gerhard and Villforth, Klaus and Schabel, Samuel and Biesalski, Markus}, year={2024}, pages={3067–3082} }' chicago: 'Hillscher, Laura M., Mark V. Höfler, Torsten Gutmann, Cassia Lux, K. Uta Clerkin, Gerhard Schwall, Klaus Villforth, Samuel Schabel, and Markus Biesalski. “Influence of TEMPO-Oxidation on Pulp Fiber Chemistry, Morphology and Mechanical Paper Sheet Properties.” Cellulose 31, no. 5 (2024): 3067–3082. https://doi.org/10.1007/s10570-024-05748-5.' ieee: 'L. M. Hillscher et al., “Influence of TEMPO-oxidation on pulp fiber chemistry, morphology and mechanical paper sheet properties,” Cellulose, vol. 31, no. 5, pp. 3067–3082, 2024, doi: 10.1007/s10570-024-05748-5.' mla: Hillscher, Laura M., et al. “Influence of TEMPO-Oxidation on Pulp Fiber Chemistry, Morphology and Mechanical Paper Sheet Properties.” Cellulose, vol. 31, no. 5, 2024, pp. 3067–3082, doi:10.1007/s10570-024-05748-5. short: L.M. Hillscher, M.V. Höfler, T. Gutmann, C. Lux, K.U. Clerkin, G. Schwall, K. Villforth, S. Schabel, M. Biesalski, Cellulose 31 (2024) 3067–3082. date_created: 2026-02-07T15:42:23Z date_updated: 2026-02-17T16:17:19Z doi: 10.1007/s10570-024-05748-5 extern: '1' intvolume: ' 31' issue: '5' language: - iso: eng page: 3067–3082 publication: Cellulose publication_identifier: issn: - 0969-0239 status: public title: Influence of TEMPO-oxidation on pulp fiber chemistry, morphology and mechanical paper sheet properties type: journal_article user_id: '100715' volume: 31 year: '2024' ... --- _id: '63970' abstract: - lang: eng text: Abstract Recent advances in solid-state nuclear magnetic resonance (NMR) spectroscopy, combined with dynamic nuclear polarization (DNP), quantum chemical DFT calculations, and gas-phase NMR spectroscopy investigating the structure and reactivity of heterogeneous catalysts are reviewed. The investigated catalysts range from classical mononuclear catalysts, like immobilized derivates of Wilkinson’s catalysts over binuclear catalysts such as the dirhodium paddlewheel catalyst to catalytic nanoparticles, employing various support materials, such as mesoporous silica gels, coordination polymers, and biomaterials such as cellulose. author: - first_name: Nadia full_name: Haro Mares, Nadia last_name: Haro Mares - first_name: Millena full_name: Logrado, Millena last_name: Logrado - first_name: Jan full_name: Kergassner, Jan last_name: Kergassner - first_name: Bingyu full_name: Zhang, Bingyu last_name: Zhang - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky citation: ama: Haro Mares N, Logrado M, Kergassner J, Zhang B, Gutmann T, Buntkowsky G. Solid-State NMR of Heterogeneous Catalysts. ChemCatChem. Published online 2024:e202401159. doi:10.1002/cctc.202401159 apa: Haro Mares, N., Logrado, M., Kergassner, J., Zhang, B., Gutmann, T., & Buntkowsky, G. (2024). Solid-State NMR of Heterogeneous Catalysts. ChemCatChem, e202401159. https://doi.org/10.1002/cctc.202401159 bibtex: '@article{Haro Mares_Logrado_Kergassner_Zhang_Gutmann_Buntkowsky_2024, title={Solid-State NMR of Heterogeneous Catalysts}, DOI={10.1002/cctc.202401159}, journal={ChemCatChem}, publisher={John Wiley & Sons, Ltd}, author={Haro Mares, Nadia and Logrado, Millena and Kergassner, Jan and Zhang, Bingyu and Gutmann, Torsten and Buntkowsky, Gerd}, year={2024}, pages={e202401159} }' chicago: Haro Mares, Nadia, Millena Logrado, Jan Kergassner, Bingyu Zhang, Torsten Gutmann, and Gerd Buntkowsky. “Solid-State NMR of Heterogeneous Catalysts.” ChemCatChem, 2024, e202401159. https://doi.org/10.1002/cctc.202401159. ieee: 'N. Haro Mares, M. Logrado, J. Kergassner, B. Zhang, T. Gutmann, and G. Buntkowsky, “Solid-State NMR of Heterogeneous Catalysts,” ChemCatChem, p. e202401159, 2024, doi: 10.1002/cctc.202401159.' mla: Haro Mares, Nadia, et al. “Solid-State NMR of Heterogeneous Catalysts.” ChemCatChem, John Wiley & Sons, Ltd, 2024, p. e202401159, doi:10.1002/cctc.202401159. short: N. Haro Mares, M. Logrado, J. Kergassner, B. Zhang, T. Gutmann, G. Buntkowsky, ChemCatChem (2024) e202401159. date_created: 2026-02-07T15:40:38Z date_updated: 2026-02-17T16:17:30Z doi: 10.1002/cctc.202401159 extern: '1' keyword: - solid-state nmr - heterogeneous catalysis - dynamic nuclear polarization - Nanocatalysis - Surface-reactions language: - iso: eng page: e202401159 publication: ChemCatChem publication_identifier: issn: - 1867-3880 publisher: John Wiley & Sons, Ltd status: public title: Solid-State NMR of Heterogeneous Catalysts type: journal_article user_id: '100715' year: '2024' ... --- _id: '64045' abstract: - lang: eng text: Abstract In this work, we report on an improved cell assembly of cylindrical electrochemical cells for 23Na in-situ solid-state NMR (ssNMR) investigations. The cell set-up is suitable for using powder electrode materials. Reproducibility of our cell assembly is analyzed by preparing two cells containing hard carbon (HC) powder as working electrode and sodium metal as reference electrode. Electrochemical storage properties of HC powder electrode derived from carbonization of sustainable cellulose are studied by ssNMR. 23Na in-situ ssNMR monitors the sodiation/desodiation of a Na{\textbar}NaPF6{\textbar}HC cell (cell 1) over a period of 22?days, showing high cell stability. After the galvanostatic process, the HC powder material is investigated by high resolution 23Na ex-situ MAS NMR. The formation of ionic sodium species in different chemical environments is obtained. Subsequently, a second Na{\textbar}NaPF6{\textbar}HC cell (cell 2) is sodiated for 11?days achieving a capacity of 220?mAh/g. 23Na ex-situ MAS NMR measurements of the HC powder material extracted from this cell clearly indicate the presence of quasi-metallic sodium species next to ionic sodium species. This observation of quasi-metallic sodium species is discussed in terms of the achieved capacity of the cell as well as of side reactions of sodium in this electrode material. author: - first_name: Edina full_name: Šić, Edina last_name: Šić - first_name: Konstantin full_name: Schutjajew, Konstantin last_name: Schutjajew - first_name: Ulrich full_name: Haagen, Ulrich last_name: Haagen - first_name: Hergen full_name: Breitzke, Hergen last_name: Breitzke - first_name: Martin full_name: Oschatz, Martin last_name: Oschatz - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann citation: ama: 'Šić E, Schutjajew K, Haagen U, et al. Electrochemical Sodium Storage in Hard Carbon Powder Electrodes Implemented in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State NMR. Chemsuschem. 2023;17:e202301300. doi:10.1002/cssc.202301300' apa: 'Šić, E., Schutjajew, K., Haagen, U., Breitzke, H., Oschatz, M., Buntkowsky, G., & Gutmann, T. (2023). Electrochemical Sodium Storage in Hard Carbon Powder Electrodes Implemented in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State NMR. Chemsuschem, 17, e202301300. https://doi.org/10.1002/cssc.202301300' bibtex: '@article{Šić_Schutjajew_Haagen_Breitzke_Oschatz_Buntkowsky_Gutmann_2023, title={Electrochemical Sodium Storage in Hard Carbon Powder Electrodes Implemented in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State NMR}, volume={17}, DOI={10.1002/cssc.202301300}, journal={Chemsuschem}, publisher={John Wiley & Sons, Ltd}, author={Šić, Edina and Schutjajew, Konstantin and Haagen, Ulrich and Breitzke, Hergen and Oschatz, Martin and Buntkowsky, Gerd and Gutmann, Torsten}, year={2023}, pages={e202301300} }' chicago: 'Šić, Edina, Konstantin Schutjajew, Ulrich Haagen, Hergen Breitzke, Martin Oschatz, Gerd Buntkowsky, and Torsten Gutmann. “Electrochemical Sodium Storage in Hard Carbon Powder Electrodes Implemented in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State NMR.” Chemsuschem 17 (2023): e202301300. https://doi.org/10.1002/cssc.202301300.' ieee: 'E. Šić et al., “Electrochemical Sodium Storage in Hard Carbon Powder Electrodes Implemented in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State NMR,” Chemsuschem, vol. 17, p. e202301300, 2023, doi: 10.1002/cssc.202301300.' mla: 'Šić, Edina, et al. “Electrochemical Sodium Storage in Hard Carbon Powder Electrodes Implemented in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State NMR.” Chemsuschem, vol. 17, John Wiley & Sons, Ltd, 2023, p. e202301300, doi:10.1002/cssc.202301300.' short: E. Šić, K. Schutjajew, U. Haagen, H. Breitzke, M. Oschatz, G. Buntkowsky, T. Gutmann, Chemsuschem 17 (2023) e202301300. date_created: 2026-02-07T16:12:13Z date_updated: 2026-02-17T16:13:10Z doi: 10.1002/cssc.202301300 extern: '1' intvolume: ' 17' keyword: - solid-state nmr - hard carbon - electrochemical cells - in-situ characterization - sodium language: - iso: eng page: e202301300 publication: Chemsuschem publication_identifier: issn: - 1864-5631 publisher: John Wiley & Sons, Ltd status: public title: 'Electrochemical Sodium Storage in Hard Carbon Powder Electrodes Implemented in an Improved Cell Assembly: Insights from In-Situ and Ex-Situ Solid-State NMR' type: journal_article user_id: '100715' volume: 17 year: '2023' ... --- _id: '64044' abstract: - lang: eng text: Abstract Polymer-derived silicon oxycarbide ceramics (SiCO) have been considered as potential anode materials for lithium- and sodium-ion batteries. To understand their electrochemical storage behavior, detailed insights into structural sites present in SiCO are required. In this work, the study of local structures in SiCO ceramics containing different amounts of carbon is presented. 13C and 29Si solid-state MAS?NMR spectroscopy combined with DFT calculations, atomistic modeling, and EPR investigations, suggest significant changes in the local structures of SiCO ceramics even by small changes in the material composition. The provided findings on SiCO structures will contribute to the research field of polymer-derived ceramics, especially to understand electrochemical storage processes of alkali metal/ions such as Na/Na+ inside such networks in the future. author: - first_name: Edina full_name: Šić, Edina last_name: Šić - first_name: Jochen full_name: Rohrer, Jochen last_name: Rohrer - first_name: Emmanuel full_name: Ricohermoso, Emmanuel last_name: Ricohermoso - first_name: Karsten full_name: Albe, Karsten last_name: Albe - first_name: Emmanuel full_name: Ionescu, Emmanuel last_name: Ionescu - first_name: Ralf full_name: Riedel, Ralf last_name: Riedel - first_name: Hergen full_name: Breitzke, Hergen last_name: Breitzke - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky citation: ama: 'Šić E, Rohrer J, Ricohermoso E, et al. SiCO Ceramics as Storage Materials for Alkali Metals/Ions: Insights on Structure Moieties from Solid-State NMR and DFT Calculations. Chemsuschem. 2023;16:e202202241. doi:10.1002/cssc.202202241' apa: 'Šić, E., Rohrer, J., Ricohermoso, E., Albe, K., Ionescu, E., Riedel, R., Breitzke, H., Gutmann, T., & Buntkowsky, G. (2023). SiCO Ceramics as Storage Materials for Alkali Metals/Ions: Insights on Structure Moieties from Solid-State NMR and DFT Calculations. Chemsuschem, 16, e202202241. https://doi.org/10.1002/cssc.202202241' bibtex: '@article{Šić_Rohrer_Ricohermoso_Albe_Ionescu_Riedel_Breitzke_Gutmann_Buntkowsky_2023, title={SiCO Ceramics as Storage Materials for Alkali Metals/Ions: Insights on Structure Moieties from Solid-State NMR and DFT Calculations}, volume={16}, DOI={10.1002/cssc.202202241}, journal={Chemsuschem}, publisher={John Wiley & Sons, Ltd}, author={Šić, Edina and Rohrer, Jochen and Ricohermoso, Emmanuel and Albe, Karsten and Ionescu, Emmanuel and Riedel, Ralf and Breitzke, Hergen and Gutmann, Torsten and Buntkowsky, Gerd}, year={2023}, pages={e202202241} }' chicago: 'Šić, Edina, Jochen Rohrer, Emmanuel Ricohermoso, Karsten Albe, Emmanuel Ionescu, Ralf Riedel, Hergen Breitzke, Torsten Gutmann, and Gerd Buntkowsky. “SiCO Ceramics as Storage Materials for Alkali Metals/Ions: Insights on Structure Moieties from Solid-State NMR and DFT Calculations.” Chemsuschem 16 (2023): e202202241. https://doi.org/10.1002/cssc.202202241.' ieee: 'E. Šić et al., “SiCO Ceramics as Storage Materials for Alkali Metals/Ions: Insights on Structure Moieties from Solid-State NMR and DFT Calculations,” Chemsuschem, vol. 16, p. e202202241, 2023, doi: 10.1002/cssc.202202241.' mla: 'Šić, Edina, et al. “SiCO Ceramics as Storage Materials for Alkali Metals/Ions: Insights on Structure Moieties from Solid-State NMR and DFT Calculations.” Chemsuschem, vol. 16, John Wiley & Sons, Ltd, 2023, p. e202202241, doi:10.1002/cssc.202202241.' short: E. Šić, J. Rohrer, E. Ricohermoso, K. Albe, E. Ionescu, R. Riedel, H. Breitzke, T. Gutmann, G. Buntkowsky, Chemsuschem 16 (2023) e202202241. date_created: 2026-02-07T16:11:46Z date_updated: 2026-02-17T16:13:11Z doi: 10.1002/cssc.202202241 extern: '1' intvolume: ' 16' keyword: - NMR spectroscopy - Ceramics - defects - density functional calculations - EPR spectroscopy language: - iso: eng page: e202202241 publication: Chemsuschem publication_identifier: issn: - 1864-5631 publisher: John Wiley & Sons, Ltd status: public title: 'SiCO Ceramics as Storage Materials for Alkali Metals/Ions: Insights on Structure Moieties from Solid-State NMR and DFT Calculations' type: journal_article user_id: '100715' volume: 16 year: '2023' ... --- _id: '64040' abstract: - lang: eng text: The oxidative dehydrogenation (ODH) of propane is of great technical importance, and supported VOx catalysts have shown promising properties for the reaction. One of the most prominent and active supports is titania, which exhibits a high activity but many questions regarding the catalyst system are still in debate. In this study, we elucidate the mechanism of the propane ODH reaction over VOx/TiO2, using P25 and ALD (atomic layer deposition) synthesized TiO2/SBA-15 as a support, with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), 51V solid-state (ss)NMR, operando multiwavelength Raman, operando UV–vis, and transient IR spectroscopies. Bare titania shows a small conversion, leading to carbon formation, and the reaction occurs at the interface between anatase and rutile. In comparison, in VOx/TiO2 catalysts, the activity shifts from titania to vanadia sites. UV-Raman spectroscopy and structural characterization data revealed the reaction to involve preferentially the V═O bonds of dimeric species rather than doubly bridged V–O–V bonds, which leads to higher propene selectivities. The active vanadium site shows a nuclearity-dependent behavior; that is, at higher loadings, when oligomeric vanadia is present, it shifts from V═O bonds to linear V–O–V bonds in oligomers, leading to less selective oxidation due to the better reducibility. Our operando/transient spectroscopic results demonstrate the direct participation of the titania support in the reaction by influencing the degree of vanadia oligomerization and enabling rapid hydrogen transfer from propane to vanadia via Ti–OH groups on anatase, accelerating the rate-determining step of the initial C–H bond breakage. The broader applicability of the results is confirmed by the behavior of the ALD-synthesized sample, which resembles that of P25. Our results highlight the detailed level of mechanistic understanding accessible from multiple spectroscopic approaches, which can be readily transferred to other materials and/or reactions. The oxidative dehydrogenation (ODH) of propane is of great technical importance, and supported VOx catalysts have shown promising properties for the reaction. One of the most prominent and active supports is titania, which exhibits a high activity but many questions regarding the catalyst system are still in debate. In this study, we elucidate the mechanism of the propane ODH reaction over VOx/TiO2, using P25 and ALD (atomic layer deposition) synthesized TiO2/SBA-15 as a support, with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), 51V solid-state (ss)NMR, operando multiwavelength Raman, operando UV–vis, and transient IR spectroscopies. Bare titania shows a small conversion, leading to carbon formation, and the reaction occurs at the interface between anatase and rutile. In comparison, in VOx/TiO2 catalysts, the activity shifts from titania to vanadia sites. UV-Raman spectroscopy and structural characterization data revealed the reaction to involve preferentially the V═O bonds of dimeric species rather than doubly bridged V–O–V bonds, which leads to higher propene selectivities. The active vanadium site shows a nuclearity-dependent behavior; that is, at higher loadings, when oligomeric vanadia is present, it shifts from V═O bonds to linear V–O–V bonds in oligomers, leading to less selective oxidation due to the better reducibility. Our operando/transient spectroscopic results demonstrate the direct participation of the titania support in the reaction by influencing the degree of vanadia oligomerization and enabling rapid hydrogen transfer from propane to vanadia via Ti–OH groups on anatase, accelerating the rate-determining step of the initial C–H bond breakage. The broader applicability of the results is confirmed by the behavior of the ALD-synthesized sample, which resembles that of P25. Our results highlight the detailed level of mechanistic understanding accessible from multiple spectroscopic approaches, which can be readily transferred to other materials and/or reactions. author: - first_name: Leon full_name: Schumacher, Leon last_name: Schumacher - first_name: Johannes full_name: Pfeiffer, Johannes last_name: Pfeiffer - first_name: Jun full_name: Shen, Jun last_name: Shen - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Hergen full_name: Breitzke, Hergen last_name: Breitzke - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky - first_name: Kathrin full_name: Hofmann, Kathrin last_name: Hofmann - first_name: Christian full_name: Hess, Christian last_name: Hess citation: ama: Schumacher L, Pfeiffer J, Shen J, et al. Collaborative Mechanistic Effects between Vanadia and Titania during the Oxidative Dehydrogenation of Propane Investigated by Operando and Transient Spectroscopies. ACS Catalysis. 2023;13(12):8139–8160. doi:10.1021/acscatal.3c01404 apa: Schumacher, L., Pfeiffer, J., Shen, J., Gutmann, T., Breitzke, H., Buntkowsky, G., Hofmann, K., & Hess, C. (2023). Collaborative Mechanistic Effects between Vanadia and Titania during the Oxidative Dehydrogenation of Propane Investigated by Operando and Transient Spectroscopies. ACS Catalysis, 13(12), 8139–8160. https://doi.org/10.1021/acscatal.3c01404 bibtex: '@article{Schumacher_Pfeiffer_Shen_Gutmann_Breitzke_Buntkowsky_Hofmann_Hess_2023, title={Collaborative Mechanistic Effects between Vanadia and Titania during the Oxidative Dehydrogenation of Propane Investigated by Operando and Transient Spectroscopies}, volume={13}, DOI={10.1021/acscatal.3c01404}, number={12}, journal={ACS Catalysis}, publisher={American Chemical Society}, author={Schumacher, Leon and Pfeiffer, Johannes and Shen, Jun and Gutmann, Torsten and Breitzke, Hergen and Buntkowsky, Gerd and Hofmann, Kathrin and Hess, Christian}, year={2023}, pages={8139–8160} }' chicago: 'Schumacher, Leon, Johannes Pfeiffer, Jun Shen, Torsten Gutmann, Hergen Breitzke, Gerd Buntkowsky, Kathrin Hofmann, and Christian Hess. “Collaborative Mechanistic Effects between Vanadia and Titania during the Oxidative Dehydrogenation of Propane Investigated by Operando and Transient Spectroscopies.” ACS Catalysis 13, no. 12 (2023): 8139–8160. https://doi.org/10.1021/acscatal.3c01404.' ieee: 'L. Schumacher et al., “Collaborative Mechanistic Effects between Vanadia and Titania during the Oxidative Dehydrogenation of Propane Investigated by Operando and Transient Spectroscopies,” ACS Catalysis, vol. 13, no. 12, pp. 8139–8160, 2023, doi: 10.1021/acscatal.3c01404.' mla: Schumacher, Leon, et al. “Collaborative Mechanistic Effects between Vanadia and Titania during the Oxidative Dehydrogenation of Propane Investigated by Operando and Transient Spectroscopies.” ACS Catalysis, vol. 13, no. 12, American Chemical Society, 2023, pp. 8139–8160, doi:10.1021/acscatal.3c01404. short: L. Schumacher, J. Pfeiffer, J. Shen, T. Gutmann, H. Breitzke, G. Buntkowsky, K. Hofmann, C. Hess, ACS Catalysis 13 (2023) 8139–8160. date_created: 2026-02-07T16:09:39Z date_updated: 2026-02-17T16:13:23Z doi: 10.1021/acscatal.3c01404 extern: '1' intvolume: ' 13' issue: '12' language: - iso: eng page: 8139–8160 publication: ACS Catalysis publisher: American Chemical Society status: public title: Collaborative Mechanistic Effects between Vanadia and Titania during the Oxidative Dehydrogenation of Propane Investigated by Operando and Transient Spectroscopies type: journal_article user_id: '100715' volume: 13 year: '2023' ... --- _id: '64008' abstract: - lang: eng text: The tailored design of bioactive materials based on cellulose or paper is still a challenging task. It requires detailed knowledge of the structure and interaction of the biofunctionalization with the carrier material at the nanoscale. In this work, the small peptide sequence Acetyl-Pro-Ala-Phe-Gly-OH (peptide 1) that can serve as a model for biofunctionalization is synthesized via solid-phase peptide synthesis, purified, and characterized by high-performance liquid chromatography (HPLC) and mass spectrometry (MS). The as-obtained peptide is bound to microcrystalline cellulose (MCC) via a wet chemical approach. Quantification of the peptide on the MCC carrier is performed by replacing l-proline (Pro) in the peptide sequence by 4-fluoro-l-proline (Pro(19F)) (peptide 2) and applying 19F magic angle spinning nuclear magnetic resonance (MAS NMR). Detailed characterization of the model system is provided by using 1H → 13C cross-polarization magic angle spinning (CP MAS NMR) combined with dynamic nuclear polarization (DNP) to enhance sensitivity. Analysis of the binding of the peptide on MCC necessitates the replacement of l-glycine (Gly) in the sequence by 13C-labeled l-glycine (Gly(13C)) (peptide 3). DNP-enhanced 13C–13C correlation experiments carried out with dipolar assisted rotational resonance (DARR) are then used to analyze the proximity between the model peptide and the MCC carrier. The strength of the dipolar coupling is estimated from the DNP-enhanced 1H → 13C CP MAS double-quantum rotational resonance (DQrotres) experiment. The obtained dipolar coupling between the 13C═O carbon of peptide 3 and the C6 carbon of the cellulose is equal to a carbon–carbon distance of about two C–O bond lengths, which strongly suggests the binding of significant amounts of the peptide on MCC via an ester bond. The tailored design of bioactive materials based on cellulose or paper is still a challenging task. It requires detailed knowledge of the structure and interaction of the biofunctionalization with the carrier material at the nanoscale. In this work, the small peptide sequence Acetyl-Pro-Ala-Phe-Gly-OH (peptide 1) that can serve as a model for biofunctionalization is synthesized via solid-phase peptide synthesis, purified, and characterized by high-performance liquid chromatography (HPLC) and mass spectrometry (MS). The as-obtained peptide is bound to microcrystalline cellulose (MCC) via a wet chemical approach. Quantification of the peptide on the MCC carrier is performed by replacing l-proline (Pro) in the peptide sequence by 4-fluoro-l-proline (Pro(19F)) (peptide 2) and applying 19F magic angle spinning nuclear magnetic resonance (MAS NMR). Detailed characterization of the model system is provided by using 1H → 13C cross-polarization magic angle spinning (CP MAS NMR) combined with dynamic nuclear polarization (DNP) to enhance sensitivity. Analysis of the binding of the peptide on MCC necessitates the replacement of l-glycine (Gly) in the sequence by 13C-labeled l-glycine (Gly(13C)) (peptide 3). DNP-enhanced 13C–13C correlation experiments carried out with dipolar assisted rotational resonance (DARR) are then used to analyze the proximity between the model peptide and the MCC carrier. The strength of the dipolar coupling is estimated from the DNP-enhanced 1H → 13C CP MAS double-quantum rotational resonance (DQrotres) experiment. The obtained dipolar coupling between the 13C═O carbon of peptide 3 and the C6 carbon of the cellulose is equal to a carbon–carbon distance of about two C–O bond lengths, which strongly suggests the binding of significant amounts of the peptide on MCC via an ester bond. author: - first_name: Waranya full_name: Limprasart, Waranya last_name: Limprasart - first_name: Mark Valentin full_name: Höfler, Mark Valentin last_name: Höfler - first_name: Nico full_name: Kunzmann, Nico last_name: Kunzmann - first_name: Lorenz full_name: Rösler, Lorenz last_name: Rösler - first_name: Kevin full_name: Herr, Kevin last_name: Herr - first_name: Hergen full_name: Breitzke, Hergen last_name: Breitzke - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann citation: ama: Limprasart W, Höfler MV, Kunzmann N, et al. Peptides as Model Systems for Biofunctionalizations of Cellulose─Synthesis and Structural Characterization by Advanced Solid-State Nuclear Magnetic Resonance Techniques. The Journal of Physical Chemistry C. 2023;127(45):22129–22138. doi:10.1021/acs.jpcc.3c05068 apa: Limprasart, W., Höfler, M. V., Kunzmann, N., Rösler, L., Herr, K., Breitzke, H., & Gutmann, T. (2023). Peptides as Model Systems for Biofunctionalizations of Cellulose─Synthesis and Structural Characterization by Advanced Solid-State Nuclear Magnetic Resonance Techniques. The Journal of Physical Chemistry C, 127(45), 22129–22138. https://doi.org/10.1021/acs.jpcc.3c05068 bibtex: '@article{Limprasart_Höfler_Kunzmann_Rösler_Herr_Breitzke_Gutmann_2023, title={Peptides as Model Systems for Biofunctionalizations of Cellulose─Synthesis and Structural Characterization by Advanced Solid-State Nuclear Magnetic Resonance Techniques}, volume={127}, DOI={10.1021/acs.jpcc.3c05068}, number={45}, journal={The Journal of Physical Chemistry C}, publisher={American Chemical Society}, author={Limprasart, Waranya and Höfler, Mark Valentin and Kunzmann, Nico and Rösler, Lorenz and Herr, Kevin and Breitzke, Hergen and Gutmann, Torsten}, year={2023}, pages={22129–22138} }' chicago: 'Limprasart, Waranya, Mark Valentin Höfler, Nico Kunzmann, Lorenz Rösler, Kevin Herr, Hergen Breitzke, and Torsten Gutmann. “Peptides as Model Systems for Biofunctionalizations of Cellulose─Synthesis and Structural Characterization by Advanced Solid-State Nuclear Magnetic Resonance Techniques.” The Journal of Physical Chemistry C 127, no. 45 (2023): 22129–22138. https://doi.org/10.1021/acs.jpcc.3c05068.' ieee: 'W. Limprasart et al., “Peptides as Model Systems for Biofunctionalizations of Cellulose─Synthesis and Structural Characterization by Advanced Solid-State Nuclear Magnetic Resonance Techniques,” The Journal of Physical Chemistry C, vol. 127, no. 45, pp. 22129–22138, 2023, doi: 10.1021/acs.jpcc.3c05068.' mla: Limprasart, Waranya, et al. “Peptides as Model Systems for Biofunctionalizations of Cellulose─Synthesis and Structural Characterization by Advanced Solid-State Nuclear Magnetic Resonance Techniques.” The Journal of Physical Chemistry C, vol. 127, no. 45, American Chemical Society, 2023, pp. 22129–22138, doi:10.1021/acs.jpcc.3c05068. short: W. Limprasart, M.V. Höfler, N. Kunzmann, L. Rösler, K. Herr, H. Breitzke, T. Gutmann, The Journal of Physical Chemistry C 127 (2023) 22129–22138. date_created: 2026-02-07T15:56:43Z date_updated: 2026-02-17T16:15:27Z doi: 10.1021/acs.jpcc.3c05068 extern: '1' intvolume: ' 127' issue: '45' language: - iso: eng page: 22129–22138 publication: The Journal of Physical Chemistry C publication_identifier: issn: - 1932-7447 publisher: American Chemical Society status: public title: Peptides as Model Systems for Biofunctionalizations of Cellulose─Synthesis and Structural Characterization by Advanced Solid-State Nuclear Magnetic Resonance Techniques type: journal_article user_id: '100715' volume: 127 year: '2023' ... --- _id: '63998' abstract: - lang: eng text: Abstract The mechanochemical synthesis of porous covalent triazine networks (CTNs), exhibiting theoretically ideal C/N ratios and high specific surface areas, is presented. Employing this solvent-free approach allows to minimize the ecological impact of the synthesis by bypassing hazardous wastes, while simultaneously observing the reactions between the individual starting materials separately for the first time. Especially the role of dichloromethane needs to be reconsidered, functioning as a linker between the nitrogen-containing node cyanuric chloride and the aromatic monomer 1,3,5-triphenylbenzene, as proven by X-ray photoelectron spectroscopy and 1H → 13C Cross-Polarization magic-angle-spinning nuclear magnetic resonance spectroscopy. This results in a drastic enhancement of the reaction rate, reducing the synthesis time down to 1 minute. Additionally, this linkage over a C1 bridge enables the incorporation of nitrogen into already synthesized polymers by post polymerization functionalization. The variation of the synthesis building blocks, namely the linker, node, and monomer, results in a variety of nitrogen-containing polymers with specific surface areas of up to 1500 m2 g−1. Therefore, the presented approach is capable to target the synthesis of various CTNs with a minimal use of chlorinated linker, rendering the concept as a sustainable alternative to the classical solution-based synthesis. author: - first_name: Annika full_name: Krusenbaum, Annika last_name: Krusenbaum - first_name: Fabien Joel Leon full_name: Kraus, Fabien Joel Leon last_name: Kraus - first_name: Stefanie full_name: Hutsch, Stefanie last_name: Hutsch - first_name: Sven full_name: Grätz, Sven last_name: Grätz - first_name: Mark Valentin full_name: Höfler, Mark Valentin last_name: Höfler - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Lars full_name: Borchardt, Lars last_name: Borchardt citation: ama: 'Krusenbaum A, Kraus FJL, Hutsch S, et al. The Rapid Mechanochemical Synthesis of Microporous Covalent Triazine Networks: Elucidating the Role of Chlorinated Linkers by a Solvent-Free Approach. Advanced Sustainable Systems. Published online 2023:2200477. doi:10.1002/adsu.202200477' apa: 'Krusenbaum, A., Kraus, F. J. L., Hutsch, S., Grätz, S., Höfler, M. V., Gutmann, T., & Borchardt, L. (2023). The Rapid Mechanochemical Synthesis of Microporous Covalent Triazine Networks: Elucidating the Role of Chlorinated Linkers by a Solvent-Free Approach. Advanced Sustainable Systems, 2200477. https://doi.org/10.1002/adsu.202200477' bibtex: '@article{Krusenbaum_Kraus_Hutsch_Grätz_Höfler_Gutmann_Borchardt_2023, title={The Rapid Mechanochemical Synthesis of Microporous Covalent Triazine Networks: Elucidating the Role of Chlorinated Linkers by a Solvent-Free Approach}, DOI={10.1002/adsu.202200477}, journal={Advanced Sustainable Systems}, author={Krusenbaum, Annika and Kraus, Fabien Joel Leon and Hutsch, Stefanie and Grätz, Sven and Höfler, Mark Valentin and Gutmann, Torsten and Borchardt, Lars}, year={2023}, pages={2200477} }' chicago: 'Krusenbaum, Annika, Fabien Joel Leon Kraus, Stefanie Hutsch, Sven Grätz, Mark Valentin Höfler, Torsten Gutmann, and Lars Borchardt. “The Rapid Mechanochemical Synthesis of Microporous Covalent Triazine Networks: Elucidating the Role of Chlorinated Linkers by a Solvent-Free Approach.” Advanced Sustainable Systems, 2023, 2200477. https://doi.org/10.1002/adsu.202200477.' ieee: 'A. Krusenbaum et al., “The Rapid Mechanochemical Synthesis of Microporous Covalent Triazine Networks: Elucidating the Role of Chlorinated Linkers by a Solvent-Free Approach,” Advanced Sustainable Systems, p. 2200477, 2023, doi: 10.1002/adsu.202200477.' mla: 'Krusenbaum, Annika, et al. “The Rapid Mechanochemical Synthesis of Microporous Covalent Triazine Networks: Elucidating the Role of Chlorinated Linkers by a Solvent-Free Approach.” Advanced Sustainable Systems, 2023, p. 2200477, doi:10.1002/adsu.202200477.' short: A. Krusenbaum, F.J.L. Kraus, S. Hutsch, S. Grätz, M.V. Höfler, T. Gutmann, L. Borchardt, Advanced Sustainable Systems (2023) 2200477. date_created: 2026-02-07T15:51:19Z date_updated: 2026-02-17T16:15:58Z doi: 10.1002/adsu.202200477 extern: '1' language: - iso: eng page: '2200477' publication: Advanced Sustainable Systems status: public title: 'The Rapid Mechanochemical Synthesis of Microporous Covalent Triazine Networks: Elucidating the Role of Chlorinated Linkers by a Solvent-Free Approach' type: journal_article user_id: '100715' year: '2023' ... --- _id: '63984' abstract: - lang: eng text: This study is seeking a better understanding of polyethylene glycol (PEG) as a solvent to promote its use in chemical synthesis. The effect of adding two solutes of interest, 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) and 5-tert-butylisophthalic acid (5-TBIPA) to PEG200 (average molar weight of 200 g·mol−1) on the solution density, viscosity, and self-diffusion coefficients is monitored in a temperature range of 298.15–358.15 K to deduce how these solutes interact with the PEG200 solvent. The effect of water, the most common impurity in PEGs, is also monitored and found to be nearly negligibly small. Addition of (5-TBIPA) increases solution density and viscosity. Combined with the observation that 5-TBIPA consistently self-diffuses at about half the rate as PEG200 at all investigated experimental conditions, this suggests strong attractive solute–solvent interactions likely through hydrogen bonding interactions. In contrast, addition of TEMPO causes lower solution densities and viscosities suggesting that the solute–solvent interactions of TEMPO lead to an overall weakening of the intermolecular interactions present compared to neat PEG200. Inspection of the viscosity and self-diffusion temperature dependence reveals slight deviations from the Arrhenius equation. Interestingly, the activation energies obtained from the viscosity and the self-diffusion data are essentially identical in values suggesting that the same dynamic processes and thus the same activation barriers govern translational motion and momentum transfer in these PEG200 solutions. author: - first_name: Markus M. full_name: Hoffmann, Markus M. last_name: Hoffmann - first_name: Nathaniel P. full_name: Randall, Nathaniel P. last_name: Randall - first_name: Miray H. full_name: Apak, Miray H. last_name: Apak - first_name: Nathaniel A. full_name: Paddock, Nathaniel A. last_name: Paddock - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky citation: ama: Hoffmann MM, Randall NP, Apak MH, Paddock NA, Gutmann T, Buntkowsky G. Solute–Solvent Interactions of 2,2,6,6-Tetramethylpiperidinyloxyl and 5-Tert-Butylisophthalic Acid in Polyethylene Glycol as Observed by Measurements of Density, Viscosity, and Self-Diffusion Coefficient. Journal of Solution Chemistry. 2023;52(6):685–707. doi:10.1007/s10953-023-01265-4 apa: Hoffmann, M. M., Randall, N. P., Apak, M. H., Paddock, N. A., Gutmann, T., & Buntkowsky, G. (2023). Solute–Solvent Interactions of 2,2,6,6-Tetramethylpiperidinyloxyl and 5-Tert-Butylisophthalic Acid in Polyethylene Glycol as Observed by Measurements of Density, Viscosity, and Self-Diffusion Coefficient. Journal of Solution Chemistry, 52(6), 685–707. https://doi.org/10.1007/s10953-023-01265-4 bibtex: '@article{Hoffmann_Randall_Apak_Paddock_Gutmann_Buntkowsky_2023, title={Solute–Solvent Interactions of 2,2,6,6-Tetramethylpiperidinyloxyl and 5-Tert-Butylisophthalic Acid in Polyethylene Glycol as Observed by Measurements of Density, Viscosity, and Self-Diffusion Coefficient}, volume={52}, DOI={10.1007/s10953-023-01265-4}, number={6}, journal={Journal of Solution Chemistry}, author={Hoffmann, Markus M. and Randall, Nathaniel P. and Apak, Miray H. and Paddock, Nathaniel A. and Gutmann, Torsten and Buntkowsky, Gerd}, year={2023}, pages={685–707} }' chicago: 'Hoffmann, Markus M., Nathaniel P. Randall, Miray H. Apak, Nathaniel A. Paddock, Torsten Gutmann, and Gerd Buntkowsky. “Solute–Solvent Interactions of 2,2,6,6-Tetramethylpiperidinyloxyl and 5-Tert-Butylisophthalic Acid in Polyethylene Glycol as Observed by Measurements of Density, Viscosity, and Self-Diffusion Coefficient.” Journal of Solution Chemistry 52, no. 6 (2023): 685–707. https://doi.org/10.1007/s10953-023-01265-4.' ieee: 'M. M. Hoffmann, N. P. Randall, M. H. Apak, N. A. Paddock, T. Gutmann, and G. Buntkowsky, “Solute–Solvent Interactions of 2,2,6,6-Tetramethylpiperidinyloxyl and 5-Tert-Butylisophthalic Acid in Polyethylene Glycol as Observed by Measurements of Density, Viscosity, and Self-Diffusion Coefficient,” Journal of Solution Chemistry, vol. 52, no. 6, pp. 685–707, 2023, doi: 10.1007/s10953-023-01265-4.' mla: Hoffmann, Markus M., et al. “Solute–Solvent Interactions of 2,2,6,6-Tetramethylpiperidinyloxyl and 5-Tert-Butylisophthalic Acid in Polyethylene Glycol as Observed by Measurements of Density, Viscosity, and Self-Diffusion Coefficient.” Journal of Solution Chemistry, vol. 52, no. 6, 2023, pp. 685–707, doi:10.1007/s10953-023-01265-4. short: M.M. Hoffmann, N.P. Randall, M.H. Apak, N.A. Paddock, T. Gutmann, G. Buntkowsky, Journal of Solution Chemistry 52 (2023) 685–707. date_created: 2026-02-07T15:45:09Z date_updated: 2026-02-17T16:16:51Z doi: 10.1007/s10953-023-01265-4 extern: '1' intvolume: ' 52' issue: '6' language: - iso: eng page: 685–707 publication: Journal of Solution Chemistry status: public title: Solute–Solvent Interactions of 2,2,6,6-Tetramethylpiperidinyloxyl and 5-Tert-Butylisophthalic Acid in Polyethylene Glycol as Observed by Measurements of Density, Viscosity, and Self-Diffusion Coefficient type: journal_article user_id: '100715' volume: 52 year: '2023' ... --- _id: '63987' abstract: - lang: eng text: An efficient approach employing 4-dimethylaminopyridine and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride as the coupling reagent is presented, which enables the functionalization of cotton linter paper substrates with the 19F spin label N-boc-cis-4-fluoro-l-proline. This spin label can be easily quantified by 19F magic angle spinning (MAS) NMR experiments to determine its loading on paper substrates. During the functionalization, the spin label stays intact, as confirmed by the 1H–19F heterocorrelation (1H → 19F CP MAS FSLG HETCOR) experiments. In combination with dynamic nuclear polarization (19F MAS DNP), the N-boc-cis-4-fluoro-l-proline spin label allows us to inspect 1 μmol/g and even lower molecule loadings on paper substrates, providing a highly sensitive local probe to analyze the structure of biofunctionalizations at the nanoscale on paper substrates in the future. An efficient approach employing 4-dimethylaminopyridine and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride as the coupling reagent is presented, which enables the functionalization of cotton linter paper substrates with the 19F spin label N-boc-cis-4-fluoro-l-proline. This spin label can be easily quantified by 19F magic angle spinning (MAS) NMR experiments to determine its loading on paper substrates. During the functionalization, the spin label stays intact, as confirmed by the 1H–19F heterocorrelation (1H → 19F CP MAS FSLG HETCOR) experiments. In combination with dynamic nuclear polarization (19F MAS DNP), the N-boc-cis-4-fluoro-l-proline spin label allows us to inspect 1 μmol/g and even lower molecule loadings on paper substrates, providing a highly sensitive local probe to analyze the structure of biofunctionalizations at the nanoscale on paper substrates in the future. author: - first_name: Mark V. full_name: Höfler, Mark V. last_name: Höfler - first_name: Waranya full_name: Limprasart, Waranya last_name: Limprasart - first_name: Lorenz full_name: Rösler, Lorenz last_name: Rösler - first_name: Max full_name: Fleckenstein, Max last_name: Fleckenstein - first_name: Martin full_name: Brodrecht, Martin last_name: Brodrecht - first_name: Kevin full_name: Herr, Kevin last_name: Herr - first_name: Jan-Lukas full_name: Schäfer, Jan-Lukas last_name: Schäfer - first_name: Markus full_name: Biesalski, Markus last_name: Biesalski - first_name: Hergen full_name: Breitzke, Hergen last_name: Breitzke - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann citation: ama: Höfler MV, Limprasart W, Rösler L, et al. Fluorine-Labeled N-Boc-l-proline as a Marker for Solid-State NMR Characterization of Biofunctionalizations on Paper Substrates. Journal of Physical Chemistry C. 2023;127(7):3570–3578. apa: Höfler, M. V., Limprasart, W., Rösler, L., Fleckenstein, M., Brodrecht, M., Herr, K., Schäfer, J.-L., Biesalski, M., Breitzke, H., & Gutmann, T. (2023). Fluorine-Labeled N-Boc-l-proline as a Marker for Solid-State NMR Characterization of Biofunctionalizations on Paper Substrates. Journal of Physical Chemistry C, 127(7), 3570–3578. bibtex: '@article{Höfler_Limprasart_Rösler_Fleckenstein_Brodrecht_Herr_Schäfer_Biesalski_Breitzke_Gutmann_2023, title={Fluorine-Labeled N-Boc-l-proline as a Marker for Solid-State NMR Characterization of Biofunctionalizations on Paper Substrates}, volume={127}, number={7}, journal={Journal of Physical Chemistry C}, publisher={American Chemical Society}, author={Höfler, Mark V. and Limprasart, Waranya and Rösler, Lorenz and Fleckenstein, Max and Brodrecht, Martin and Herr, Kevin and Schäfer, Jan-Lukas and Biesalski, Markus and Breitzke, Hergen and Gutmann, Torsten}, year={2023}, pages={3570–3578} }' chicago: 'Höfler, Mark V., Waranya Limprasart, Lorenz Rösler, Max Fleckenstein, Martin Brodrecht, Kevin Herr, Jan-Lukas Schäfer, Markus Biesalski, Hergen Breitzke, and Torsten Gutmann. “Fluorine-Labeled N-Boc-l-Proline as a Marker for Solid-State NMR Characterization of Biofunctionalizations on Paper Substrates.” Journal of Physical Chemistry C 127, no. 7 (2023): 3570–3578.' ieee: M. V. Höfler et al., “Fluorine-Labeled N-Boc-l-proline as a Marker for Solid-State NMR Characterization of Biofunctionalizations on Paper Substrates,” Journal of Physical Chemistry C, vol. 127, no. 7, pp. 3570–3578, 2023. mla: Höfler, Mark V., et al. “Fluorine-Labeled N-Boc-l-Proline as a Marker for Solid-State NMR Characterization of Biofunctionalizations on Paper Substrates.” Journal of Physical Chemistry C, vol. 127, no. 7, American Chemical Society, 2023, pp. 3570–3578. short: M.V. Höfler, W. Limprasart, L. Rösler, M. Fleckenstein, M. Brodrecht, K. Herr, J.-L. Schäfer, M. Biesalski, H. Breitzke, T. Gutmann, Journal of Physical Chemistry C 127 (2023) 3570–3578. date_created: 2026-02-07T15:46:14Z date_updated: 2026-02-17T16:16:46Z extern: '1' intvolume: ' 127' issue: '7' language: - iso: eng page: 3570–3578 publication: Journal of Physical Chemistry C publication_identifier: issn: - 1932-7447 publisher: American Chemical Society status: public title: Fluorine-Labeled N-Boc-l-proline as a Marker for Solid-State NMR Characterization of Biofunctionalizations on Paper Substrates type: journal_article user_id: '100715' volume: 127 year: '2023' ... --- _id: '63971' abstract: - lang: eng text: 'The physicochemical effects of decorating pore walls of high surface area materials with functional groups are not sufficiently understood, despite the use of these materials in a multitude of applications such as catalysis, separations, or drug delivery. In this study, the influence of 3-amino-propyl triethoxysilane (APTES)-modified SBA-15 on the dynamics of deuterated ethylene glycol (EG-d4) is inspected by comparing three systems: EG-d4 in the bulk phase (sample 1), EG-d4 confined in SBA-15 (sample 2), and EG-d4 confined in SBA-15 modified with APTES (sample 3). The phase behavior (i.e., melting, crystallization, glass formation, etc.) of EG-d4 in these three systems is studied by differential scanning calorimetry. Through line shape analysis of the 2H solid-state NMR (2H ssNMR) spectra of the three systems recorded at different temperatures, two signal patterns, (i) a Lorentzian (liquid-like) and (ii) a Pake pattern (solid-like), are identified from which the distribution of activation energies for the dynamic processes is calculated employing a two-phase model. The physicochemical effects of decorating pore walls of high surface area materials with functional groups are not sufficiently understood, despite the use of these materials in a multitude of applications such as catalysis, separations, or drug delivery. In this study, the influence of 3-amino-propyl triethoxysilane (APTES)-modified SBA-15 on the dynamics of deuterated ethylene glycol (EG-d4) is inspected by comparing three systems: EG-d4 in the bulk phase (sample 1), EG-d4 confined in SBA-15 (sample 2), and EG-d4 confined in SBA-15 modified with APTES (sample 3). The phase behavior (i.e., melting, crystallization, glass formation, etc.) of EG-d4 in these three systems is studied by differential scanning calorimetry. Through line shape analysis of the 2H solid-state NMR (2H ssNMR) spectra of the three systems recorded at different temperatures, two signal patterns, (i) a Lorentzian (liquid-like) and (ii) a Pake pattern (solid-like), are identified from which the distribution of activation energies for the dynamic processes is calculated employing a two-phase model.' author: - first_name: Nadia B. full_name: Haro Mares, Nadia B. last_name: Haro Mares - first_name: Martin full_name: Brodrecht, Martin last_name: Brodrecht - first_name: Till full_name: Wissel, Till last_name: Wissel - first_name: Sonja C. full_name: Döller, Sonja C. last_name: Döller - first_name: Lorenz full_name: Rösler, Lorenz last_name: Rösler - first_name: Hergen full_name: Breitzke, Hergen last_name: Breitzke - first_name: Markus M. full_name: Hoffmann, Markus M. last_name: Hoffmann - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky citation: ama: Haro Mares NB, Brodrecht M, Wissel T, et al. Influence of APTES-Decorated Mesoporous Silica on the Dynamics of Ethylene Glycol Molecules─Insights from Variable Temperature 2H Solid-State NMR. The Journal of Physical Chemistry C. 2023;127(39):19735–19746. doi:10.1021/acs.jpcc.3c03671 apa: Haro Mares, N. B., Brodrecht, M., Wissel, T., Döller, S. C., Rösler, L., Breitzke, H., Hoffmann, M. M., Gutmann, T., & Buntkowsky, G. (2023). Influence of APTES-Decorated Mesoporous Silica on the Dynamics of Ethylene Glycol Molecules─Insights from Variable Temperature 2H Solid-State NMR. The Journal of Physical Chemistry C, 127(39), 19735–19746. https://doi.org/10.1021/acs.jpcc.3c03671 bibtex: '@article{Haro Mares_Brodrecht_Wissel_Döller_Rösler_Breitzke_Hoffmann_Gutmann_Buntkowsky_2023, title={Influence of APTES-Decorated Mesoporous Silica on the Dynamics of Ethylene Glycol Molecules─Insights from Variable Temperature 2H Solid-State NMR}, volume={127}, DOI={10.1021/acs.jpcc.3c03671}, number={39}, journal={The Journal of Physical Chemistry C}, publisher={American Chemical Society}, author={Haro Mares, Nadia B. and Brodrecht, Martin and Wissel, Till and Döller, Sonja C. and Rösler, Lorenz and Breitzke, Hergen and Hoffmann, Markus M. and Gutmann, Torsten and Buntkowsky, Gerd}, year={2023}, pages={19735–19746} }' chicago: 'Haro Mares, Nadia B., Martin Brodrecht, Till Wissel, Sonja C. Döller, Lorenz Rösler, Hergen Breitzke, Markus M. Hoffmann, Torsten Gutmann, and Gerd Buntkowsky. “Influence of APTES-Decorated Mesoporous Silica on the Dynamics of Ethylene Glycol Molecules─Insights from Variable Temperature 2H Solid-State NMR.” The Journal of Physical Chemistry C 127, no. 39 (2023): 19735–19746. https://doi.org/10.1021/acs.jpcc.3c03671.' ieee: 'N. B. Haro Mares et al., “Influence of APTES-Decorated Mesoporous Silica on the Dynamics of Ethylene Glycol Molecules─Insights from Variable Temperature 2H Solid-State NMR,” The Journal of Physical Chemistry C, vol. 127, no. 39, pp. 19735–19746, 2023, doi: 10.1021/acs.jpcc.3c03671.' mla: Haro Mares, Nadia B., et al. “Influence of APTES-Decorated Mesoporous Silica on the Dynamics of Ethylene Glycol Molecules─Insights from Variable Temperature 2H Solid-State NMR.” The Journal of Physical Chemistry C, vol. 127, no. 39, American Chemical Society, 2023, pp. 19735–19746, doi:10.1021/acs.jpcc.3c03671. short: N.B. Haro Mares, M. Brodrecht, T. Wissel, S.C. Döller, L. Rösler, H. Breitzke, M.M. Hoffmann, T. Gutmann, G. Buntkowsky, The Journal of Physical Chemistry C 127 (2023) 19735–19746. date_created: 2026-02-07T15:40:57Z date_updated: 2026-02-17T16:17:28Z doi: 10.1021/acs.jpcc.3c03671 extern: '1' intvolume: ' 127' issue: '39' language: - iso: eng page: 19735–19746 publication: The Journal of Physical Chemistry C publication_identifier: issn: - 1932-7447 publisher: American Chemical Society status: public title: Influence of APTES-Decorated Mesoporous Silica on the Dynamics of Ethylene Glycol Molecules─Insights from Variable Temperature 2H Solid-State NMR type: journal_article user_id: '100715' volume: 127 year: '2023' ... --- _id: '63946' abstract: - lang: eng text: Two different mesoporous silica materials (SBA-15 and MCM 41) were impregnated with four different, commercially available surfactants, namely, E5, PEG 200, C10E6, and Triton X-100. Differential scanning calorimetry was employed to confirm the confinement of the surfactants in the pores of their host materials. Dynamic nuclear polarization enhanced solid state 13C magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra were recorded for these materials, showing that both the direct as well as the indirect polarization transfer pathways are active for the carbons of the polyethylene glycol moieties of the surfactants. The presence of the indirect polarization pathway implies the presence of molecular motion with correlation times faster than the inverse Larmor frequency of the observed signals. The intensities of the signals were determined, and an approach based on relative intensities was employed to ensure comparability throughout the samples. From these data, the interactions of the surfactants with the pore walls could be determined. Additionally, a model describing the surfactants’ arrangement in the pores was developed. It was concluded that all carbons of the hydrophilic surfactants, E5 and PEG 200, interact with the silica walls in a similar fashion, leading to similar polarization transfer pathway patterns for all observed signals. For the amphiphilic surfactants C10E6 and Triton X-100, the terminal hydroxyl group mediates the majority of the interactions with the pore walls and the polarizing agent. Two different mesoporous silica materials (SBA-15 and MCM 41) were impregnated with four different, commercially available surfactants, namely, E5, PEG 200, C10E6, and Triton X-100. Differential scanning calorimetry was employed to confirm the confinement of the surfactants in the pores of their host materials. Dynamic nuclear polarization enhanced solid state 13C magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra were recorded for these materials, showing that both the direct as well as the indirect polarization transfer pathways are active for the carbons of the polyethylene glycol moieties of the surfactants. The presence of the indirect polarization pathway implies the presence of molecular motion with correlation times faster than the inverse Larmor frequency of the observed signals. The intensities of the signals were determined, and an approach based on relative intensities was employed to ensure comparability throughout the samples. From these data, the interactions of the surfactants with the pore walls could be determined. Additionally, a model describing the surfactants’ arrangement in the pores was developed. It was concluded that all carbons of the hydrophilic surfactants, E5 and PEG 200, interact with the silica walls in a similar fashion, leading to similar polarization transfer pathway patterns for all observed signals. For the amphiphilic surfactants C10E6 and Triton X-100, the terminal hydroxyl group mediates the majority of the interactions with the pore walls and the polarizing agent. author: - first_name: Sonja C. full_name: Döller, Sonja C. last_name: Döller - first_name: Martin full_name: Brodrecht, Martin last_name: Brodrecht - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Markus full_name: Hoffmann, Markus last_name: Hoffmann - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky citation: ama: Döller SC, Brodrecht M, Gutmann T, Hoffmann M, Buntkowsky G. Direct and Indirect DNP NMR Uncovers the Interplay of Surfactants with Their Mesoporous Host Material. The Journal of Physical Chemistry C. 2023;127(25):12125–12134. doi:10.1021/acs.jpcc.3c01946 apa: Döller, S. C., Brodrecht, M., Gutmann, T., Hoffmann, M., & Buntkowsky, G. (2023). Direct and Indirect DNP NMR Uncovers the Interplay of Surfactants with Their Mesoporous Host Material. The Journal of Physical Chemistry C, 127(25), 12125–12134. https://doi.org/10.1021/acs.jpcc.3c01946 bibtex: '@article{Döller_Brodrecht_Gutmann_Hoffmann_Buntkowsky_2023, title={Direct and Indirect DNP NMR Uncovers the Interplay of Surfactants with Their Mesoporous Host Material}, volume={127}, DOI={10.1021/acs.jpcc.3c01946}, number={25}, journal={The Journal of Physical Chemistry C}, publisher={American Chemical Society}, author={Döller, Sonja C. and Brodrecht, Martin and Gutmann, Torsten and Hoffmann, Markus and Buntkowsky, Gerd}, year={2023}, pages={12125–12134} }' chicago: 'Döller, Sonja C., Martin Brodrecht, Torsten Gutmann, Markus Hoffmann, and Gerd Buntkowsky. “Direct and Indirect DNP NMR Uncovers the Interplay of Surfactants with Their Mesoporous Host Material.” The Journal of Physical Chemistry C 127, no. 25 (2023): 12125–12134. https://doi.org/10.1021/acs.jpcc.3c01946.' ieee: 'S. C. Döller, M. Brodrecht, T. Gutmann, M. Hoffmann, and G. Buntkowsky, “Direct and Indirect DNP NMR Uncovers the Interplay of Surfactants with Their Mesoporous Host Material,” The Journal of Physical Chemistry C, vol. 127, no. 25, pp. 12125–12134, 2023, doi: 10.1021/acs.jpcc.3c01946.' mla: Döller, Sonja C., et al. “Direct and Indirect DNP NMR Uncovers the Interplay of Surfactants with Their Mesoporous Host Material.” The Journal of Physical Chemistry C, vol. 127, no. 25, American Chemical Society, 2023, pp. 12125–12134, doi:10.1021/acs.jpcc.3c01946. short: S.C. Döller, M. Brodrecht, T. Gutmann, M. Hoffmann, G. Buntkowsky, The Journal of Physical Chemistry C 127 (2023) 12125–12134. date_created: 2026-02-07T09:12:13Z date_updated: 2026-02-17T16:18:30Z doi: 10.1021/acs.jpcc.3c01946 extern: '1' intvolume: ' 127' issue: '25' language: - iso: eng page: 12125–12134 publication: The Journal of Physical Chemistry C publication_identifier: issn: - 1932-7447 publisher: American Chemical Society status: public title: Direct and Indirect DNP NMR Uncovers the Interplay of Surfactants with Their Mesoporous Host Material type: journal_article user_id: '100715' volume: 127 year: '2023' ... --- _id: '63922' author: - first_name: Nargiz B. full_name: Asanbaeva, Nargiz B. last_name: Asanbaeva - first_name: Sergey A. full_name: Dobrynin, Sergey A. last_name: Dobrynin - first_name: Denis A. full_name: Morozov, Denis A. last_name: Morozov - first_name: Nadia full_name: Haro-Mares, Nadia last_name: Haro-Mares - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky - first_name: Elena G. full_name: Bagryanskaya, Elena G. last_name: Bagryanskaya citation: ama: Asanbaeva NB, Dobrynin SA, Morozov DA, et al. An EPR Study on Highly Stable Nitroxyl-Nitroxyl Biradicals for Dynamic Nuclear Polarization Applications at High Magnetic Fields. Molecules. 2023;28(4):1926. doi:10.3390/molecules28041926 apa: Asanbaeva, N. B., Dobrynin, S. A., Morozov, D. A., Haro-Mares, N., Gutmann, T., Buntkowsky, G., & Bagryanskaya, E. G. (2023). An EPR Study on Highly Stable Nitroxyl-Nitroxyl Biradicals for Dynamic Nuclear Polarization Applications at High Magnetic Fields. Molecules, 28(4), 1926. https://doi.org/10.3390/molecules28041926 bibtex: '@article{Asanbaeva_Dobrynin_Morozov_Haro-Mares_Gutmann_Buntkowsky_Bagryanskaya_2023, title={An EPR Study on Highly Stable Nitroxyl-Nitroxyl Biradicals for Dynamic Nuclear Polarization Applications at High Magnetic Fields}, volume={28}, DOI={10.3390/molecules28041926}, number={4}, journal={Molecules}, author={Asanbaeva, Nargiz B. and Dobrynin, Sergey A. and Morozov, Denis A. and Haro-Mares, Nadia and Gutmann, Torsten and Buntkowsky, Gerd and Bagryanskaya, Elena G.}, year={2023}, pages={1926} }' chicago: 'Asanbaeva, Nargiz B., Sergey A. Dobrynin, Denis A. Morozov, Nadia Haro-Mares, Torsten Gutmann, Gerd Buntkowsky, and Elena G. Bagryanskaya. “An EPR Study on Highly Stable Nitroxyl-Nitroxyl Biradicals for Dynamic Nuclear Polarization Applications at High Magnetic Fields.” Molecules 28, no. 4 (2023): 1926. https://doi.org/10.3390/molecules28041926.' ieee: 'N. B. Asanbaeva et al., “An EPR Study on Highly Stable Nitroxyl-Nitroxyl Biradicals for Dynamic Nuclear Polarization Applications at High Magnetic Fields,” Molecules, vol. 28, no. 4, p. 1926, 2023, doi: 10.3390/molecules28041926.' mla: Asanbaeva, Nargiz B., et al. “An EPR Study on Highly Stable Nitroxyl-Nitroxyl Biradicals for Dynamic Nuclear Polarization Applications at High Magnetic Fields.” Molecules, vol. 28, no. 4, 2023, p. 1926, doi:10.3390/molecules28041926. short: N.B. Asanbaeva, S.A. Dobrynin, D.A. Morozov, N. Haro-Mares, T. Gutmann, G. Buntkowsky, E.G. Bagryanskaya, Molecules 28 (2023) 1926. date_created: 2026-02-07T08:57:19Z date_updated: 2026-02-20T08:12:12Z doi: 10.3390/molecules28041926 extern: '1' intvolume: ' 28' issue: '4' language: - iso: eng page: '1926' publication: Molecules publication_identifier: issn: - 1420-3049 status: public title: An EPR Study on Highly Stable Nitroxyl-Nitroxyl Biradicals for Dynamic Nuclear Polarization Applications at High Magnetic Fields type: journal_article user_id: '100715' volume: 28 year: '2023' ... --- _id: '64042' abstract: - lang: eng text: Abstract Polymer-derived silicon carbonitride ceramic (SiCN) is used as an electrode material to prepare cylindrical sodium/sodium ion cells for solid-state NMR investigations. During galvanostatic cycling structural changes of the environment of sodium/sodium ions are investigated by applying 23Na in-situ solid-state NMR. Changes of the signals assigned to sodium metal, intercalated sodium cation and sodium cation originating from the electrolyte are monitored as well as the occurrence of an additional signal in the region of metallic sodium. The intensity of this additional signal changes periodically with the cycling process indicating the reversibility of structures formed and deformed during the galvanostatic cycling. To identify interactions of sodium/sodium ions with the SiCN electrode materials, the cycled SiCN material is studied by 23Na ex-situ MAS NMR at high spinning rates of 20 and 50 kHz to obtain appropriate spectral resolution. author: - first_name: Edina full_name: Sic, Edina last_name: Sic - first_name: Marco full_name: Melzi d’Eril, Marco last_name: Melzi d’Eril - first_name: Konstantin full_name: Schutjajew, Konstantin last_name: Schutjajew - first_name: Magdalena J. full_name: Graczyk-Zajac, Magdalena J. last_name: Graczyk-Zajac - first_name: Hergen full_name: Breitzke, Hergen last_name: Breitzke - first_name: Ralf full_name: Riedel, Ralf last_name: Riedel - first_name: Martin full_name: Oschatz, Martin last_name: Oschatz - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky citation: ama: Sic E, Melzi d’Eril M, Schutjajew K, et al. SiCN Ceramics as Electrode Materials for Sodium/Sodium Ion Cells Insights from 23Na In-Situ Solid-State NMR. Batteries and Supercaps. 2022;5:e202200066. doi:10.1002/batt.202200066 apa: Sic, E., Melzi d’Eril, M., Schutjajew, K., Graczyk-Zajac, M. J., Breitzke, H., Riedel, R., Oschatz, M., Gutmann, T., & Buntkowsky, G. (2022). SiCN Ceramics as Electrode Materials for Sodium/Sodium Ion Cells Insights from 23Na In-Situ Solid-State NMR. Batteries and Supercaps, 5, e202200066. https://doi.org/10.1002/batt.202200066 bibtex: '@article{Sic_Melzi d’Eril_Schutjajew_Graczyk-Zajac_Breitzke_Riedel_Oschatz_Gutmann_Buntkowsky_2022, title={SiCN Ceramics as Electrode Materials for Sodium/Sodium Ion Cells Insights from 23Na In-Situ Solid-State NMR}, volume={5}, DOI={10.1002/batt.202200066}, journal={Batteries and Supercaps}, author={Sic, Edina and Melzi d’Eril, Marco and Schutjajew, Konstantin and Graczyk-Zajac, Magdalena J. and Breitzke, Hergen and Riedel, Ralf and Oschatz, Martin and Gutmann, Torsten and Buntkowsky, Gerd}, year={2022}, pages={e202200066} }' chicago: 'Sic, Edina, Marco Melzi d’Eril, Konstantin Schutjajew, Magdalena J. Graczyk-Zajac, Hergen Breitzke, Ralf Riedel, Martin Oschatz, Torsten Gutmann, and Gerd Buntkowsky. “SiCN Ceramics as Electrode Materials for Sodium/Sodium Ion Cells Insights from 23Na In-Situ Solid-State NMR.” Batteries and Supercaps 5 (2022): e202200066. https://doi.org/10.1002/batt.202200066.' ieee: 'E. Sic et al., “SiCN Ceramics as Electrode Materials for Sodium/Sodium Ion Cells Insights from 23Na In-Situ Solid-State NMR,” Batteries and Supercaps, vol. 5, p. e202200066, 2022, doi: 10.1002/batt.202200066.' mla: Sic, Edina, et al. “SiCN Ceramics as Electrode Materials for Sodium/Sodium Ion Cells Insights from 23Na In-Situ Solid-State NMR.” Batteries and Supercaps, vol. 5, 2022, p. e202200066, doi:10.1002/batt.202200066. short: E. Sic, M. Melzi d’Eril, K. Schutjajew, M.J. Graczyk-Zajac, H. Breitzke, R. Riedel, M. Oschatz, T. Gutmann, G. Buntkowsky, Batteries and Supercaps 5 (2022) e202200066. date_created: 2026-02-07T16:10:25Z date_updated: 2026-02-17T16:13:15Z doi: 10.1002/batt.202200066 extern: '1' intvolume: ' 5' language: - iso: eng page: e202200066 publication: Batteries and Supercaps status: public title: SiCN Ceramics as Electrode Materials for Sodium/Sodium Ion Cells Insights from 23Na In-Situ Solid-State NMR type: journal_article user_id: '100715' volume: 5 year: '2022' ... --- _id: '64030' abstract: - lang: eng text: A novel, efficient approach for the functionalization of microcrystalline cellulose (MCC) is presented. The as-obtained material allows the immobilization of chiral dirhodium catalysts preserving their enantioselectivity in asymmetric cyclopropanation reactions. As model, microcrystalline cellulose is modified with a polyethylene glycol derived linker, and Rh-2(S-DOSP)(4) is grafted on the material to produce a heterogeneous catalyst. SEM images at different stages of the immobilization show an unchanging uniform morphology, providing constantly good separation characteristics. The modification of the cellulose material with the polyethylene derived linker and the immobilization process are monitored using DNP enhanced H-1 -{\textgreater} C-13 CP MAS NMR, quantitative F-19 MAS NMR, TGA and ICP-OES analysis, confirming the success of the immobilization as well as the stability of bonds between the used linker molecule and the cellulose material. Finally, the evaluation of the produced catalyst is demonstrated in the asymmetric cyclopropanation reaction between styrene and methyl(E)-2-diazo-4-phenylbut-3-enoate showing excellent enantioselectivity with an ee of nearly 90% over a wide temperature range as well as good recyclability characteristics in four consecutive catalysis cycles. author: - first_name: L. full_name: Roesler, L. last_name: Roesler - first_name: M. V. full_name: Hoefler, M. V. last_name: Hoefler - first_name: H. full_name: Breitzke, H. last_name: Breitzke - first_name: T. full_name: Wissel, T. last_name: Wissel - first_name: K. full_name: Herr, K. last_name: Herr - first_name: H. full_name: Heise, H. last_name: Heise - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: G. full_name: Buntkowsky, G. last_name: Buntkowsky citation: ama: Roesler L, Hoefler MV, Breitzke H, et al. Dirhodium complex immobilization on modified cellulose for highly selective heterogeneous cyclopropanation reactions. Cellulose. 2022;29(11):6283–6299. doi:10.1007/s10570-022-04654-y apa: Roesler, L., Hoefler, M. V., Breitzke, H., Wissel, T., Herr, K., Heise, H., Gutmann, T., & Buntkowsky, G. (2022). Dirhodium complex immobilization on modified cellulose for highly selective heterogeneous cyclopropanation reactions. Cellulose, 29(11), 6283–6299. https://doi.org/10.1007/s10570-022-04654-y bibtex: '@article{Roesler_Hoefler_Breitzke_Wissel_Herr_Heise_Gutmann_Buntkowsky_2022, title={Dirhodium complex immobilization on modified cellulose for highly selective heterogeneous cyclopropanation reactions}, volume={29}, DOI={10.1007/s10570-022-04654-y}, number={11}, journal={Cellulose}, author={Roesler, L. and Hoefler, M. V. and Breitzke, H. and Wissel, T. and Herr, K. and Heise, H. and Gutmann, Torsten and Buntkowsky, G.}, year={2022}, pages={6283–6299} }' chicago: 'Roesler, L., M. V. Hoefler, H. Breitzke, T. Wissel, K. Herr, H. Heise, Torsten Gutmann, and G. Buntkowsky. “Dirhodium Complex Immobilization on Modified Cellulose for Highly Selective Heterogeneous Cyclopropanation Reactions.” Cellulose 29, no. 11 (2022): 6283–6299. https://doi.org/10.1007/s10570-022-04654-y.' ieee: 'L. Roesler et al., “Dirhodium complex immobilization on modified cellulose for highly selective heterogeneous cyclopropanation reactions,” Cellulose, vol. 29, no. 11, pp. 6283–6299, 2022, doi: 10.1007/s10570-022-04654-y.' mla: Roesler, L., et al. “Dirhodium Complex Immobilization on Modified Cellulose for Highly Selective Heterogeneous Cyclopropanation Reactions.” Cellulose, vol. 29, no. 11, 2022, pp. 6283–6299, doi:10.1007/s10570-022-04654-y. short: L. Roesler, M.V. Hoefler, H. Breitzke, T. Wissel, K. Herr, H. Heise, T. Gutmann, G. Buntkowsky, Cellulose 29 (2022) 6283–6299. date_created: 2026-02-07T16:06:07Z date_updated: 2026-02-17T16:13:54Z doi: 10.1007/s10570-022-04654-y extern: '1' intvolume: ' 29' issue: '11' language: - iso: eng page: 6283–6299 publication: Cellulose publication_identifier: issn: - 0969-0239 status: public title: Dirhodium complex immobilization on modified cellulose for highly selective heterogeneous cyclopropanation reactions type: journal_article user_id: '100715' volume: 29 year: '2022' ... --- _id: '63994' abstract: - lang: eng text: Six cluster salts which consist of hexanuclear cluster anions [Nb6Cl12iX6a]2– (X = Cl or Br) and protonated crown ether molecules (15-crown-5 (15cr5) and 12-crown-4 (12cr4)) or crown ether-stabilized oxonium cations as well as one compound consisting of neutral cluster units, [Nb6Cl16(H2O)2]·4 dioxane, were synthesized in good to high yields. The single-crystal X-ray structures of six of these compounds were determined. The cation/anion ratios and the bond distances confirm in all cases oxidized cluster cores with 14 cluster-based electrons. The cations of the cluster salts are either sandwich-type dimers of the formula [(15cr5)H]22+ or [(15cr5)(H3O)]22+ with the protons or oxonium ions embedded in between the crown ether rings or monomeric units in the case of [(12cr4)H]+. 1H NMR investigations show that the cluster salts are strong Brønsted acids. The fact that the cluster core of [Nb6Cl16(H2O)2]·4 dioxane is oxidized but still carries water ligands indicates that within the multi-step reaction sequence of the formation of the cluster-supported acids, the oxidation step happens much faster than the ligand exchange steps. Temperature-dependent 2H MAS NMR spectra of deuterium-exchanged [(15cr5)H]2[Nb6Cl18]·2 CHCl3 are indicative of dynamic processes of the hydrogen-bonded protons within the crown ether molecule. Six cluster salts which consist of hexanuclear cluster anions [Nb6Cl12iX6a]2– (X = Cl or Br) and protonated crown ether molecules (15-crown-5 (15cr5) and 12-crown-4 (12cr4)) or crown ether-stabilized oxonium cations as well as one compound consisting of neutral cluster units, [Nb6Cl16(H2O)2]·4 dioxane, were synthesized in good to high yields. The single-crystal X-ray structures of six of these compounds were determined. The cation/anion ratios and the bond distances confirm in all cases oxidized cluster cores with 14 cluster-based electrons. The cations of the cluster salts are either sandwich-type dimers of the formula [(15cr5)H]22+ or [(15cr5)(H3O)]22+ with the protons or oxonium ions embedded in between the crown ether rings or monomeric units in the case of [(12cr4)H]+. 1H NMR investigations show that the cluster salts are strong Brønsted acids. The fact that the cluster core of [Nb6Cl16(H2O)2]·4 dioxane is oxidized but still carries water ligands indicates that within the multi-step reaction sequence of the formation of the cluster-supported acids, the oxidation step happens much faster than the ligand exchange steps. Temperature-dependent 2H MAS NMR spectra of deuterium-exchanged [(15cr5)H]2[Nb6Cl18]·2 CHCl3 are indicative of dynamic processes of the hydrogen-bonded protons within the crown ether molecule. author: - first_name: Jonas full_name: Koenig, Jonas last_name: Koenig - first_name: Torsten full_name: Gutmann, Torsten id: '118165' last_name: Gutmann - first_name: Gerd full_name: Buntkowsky, Gerd last_name: Buntkowsky - first_name: Martin full_name: Koeckerling, Martin last_name: Koeckerling citation: ama: 'Koenig J, Gutmann T, Buntkowsky G, Koeckerling M. Strong Cluster-Supported Brønsted Acids: Hexanuclear Niobium Cluster Compounds with Protonated Crown Ether Cations: (Crown-H)2[Nb6Cl12iX6a] (X = Cl or Br) and the Intermediate [Nb6Cl16(H2O)2]·4 dioxane. Inorganic Chemistry. 2022;61(40):15983–15990.' apa: 'Koenig, J., Gutmann, T., Buntkowsky, G., & Koeckerling, M. (2022). Strong Cluster-Supported Brønsted Acids: Hexanuclear Niobium Cluster Compounds with Protonated Crown Ether Cations: (Crown-H)2[Nb6Cl12iX6a] (X = Cl or Br) and the Intermediate [Nb6Cl16(H2O)2]·4 dioxane. Inorganic Chemistry, 61(40), 15983–15990.' bibtex: '@article{Koenig_Gutmann_Buntkowsky_Koeckerling_2022, title={Strong Cluster-Supported Brønsted Acids: Hexanuclear Niobium Cluster Compounds with Protonated Crown Ether Cations: (Crown-H)2[Nb6Cl12iX6a] (X = Cl or Br) and the Intermediate [Nb6Cl16(H2O)2]·4 dioxane}, volume={61}, number={40}, journal={Inorganic Chemistry}, publisher={American Chemical Society}, author={Koenig, Jonas and Gutmann, Torsten and Buntkowsky, Gerd and Koeckerling, Martin}, year={2022}, pages={15983–15990} }' chicago: 'Koenig, Jonas, Torsten Gutmann, Gerd Buntkowsky, and Martin Koeckerling. “Strong Cluster-Supported Brønsted Acids: Hexanuclear Niobium Cluster Compounds with Protonated Crown Ether Cations: (Crown-H)2[Nb6Cl12iX6a] (X = Cl or Br) and the Intermediate [Nb6Cl16(H2O)2]·4 Dioxane.” Inorganic Chemistry 61, no. 40 (2022): 15983–15990.' ieee: 'J. Koenig, T. Gutmann, G. Buntkowsky, and M. Koeckerling, “Strong Cluster-Supported Brønsted Acids: Hexanuclear Niobium Cluster Compounds with Protonated Crown Ether Cations: (Crown-H)2[Nb6Cl12iX6a] (X = Cl or Br) and the Intermediate [Nb6Cl16(H2O)2]·4 dioxane,” Inorganic Chemistry, vol. 61, no. 40, pp. 15983–15990, 2022.' mla: 'Koenig, Jonas, et al. “Strong Cluster-Supported Brønsted Acids: Hexanuclear Niobium Cluster Compounds with Protonated Crown Ether Cations: (Crown-H)2[Nb6Cl12iX6a] (X = Cl or Br) and the Intermediate [Nb6Cl16(H2O)2]·4 Dioxane.” Inorganic Chemistry, vol. 61, no. 40, American Chemical Society, 2022, pp. 15983–15990.' short: J. Koenig, T. Gutmann, G. Buntkowsky, M. Koeckerling, Inorganic Chemistry 61 (2022) 15983–15990. date_created: 2026-02-07T15:48:14Z date_updated: 2026-02-17T16:16:07Z extern: '1' intvolume: ' 61' issue: '40' language: - iso: eng page: 15983–15990 publication: Inorganic Chemistry publisher: American Chemical Society status: public title: 'Strong Cluster-Supported Brønsted Acids: Hexanuclear Niobium Cluster Compounds with Protonated Crown Ether Cations: (Crown-H)2[Nb6Cl12iX6a] (X = Cl or Br) and the Intermediate [Nb6Cl16(H2O)2]·4 dioxane' type: journal_article user_id: '100715' volume: 61 year: '2022' ...