---
_id: '63950'
abstract:
- lang: eng
text: Sodium-ion batteries are at the forefront of new, sustainable energy systems
required for the global energy transition. 23Na in situ solid-state nuclear magnetic
resonance spectroscopy is capable of unraveling structures in working electrochemical
cells during the charging and discharging processes. To evaluate its suitability
for long-term studies, local sodium environments in sodium/sodium ion cells based
on silicon carbonitride and hard carbon materials are tracked for up to 49 cycles
(228.5?h). The formation of dendrites as well as the decay of a secondary metallic
sodium species is observed, and local structures are analyzed up to the point
of capacity degradation and cell failure. Initial points of cell breakdown are
reflected in the NMR data by characteristic changes in signal intensities, whereas
the degradation of the cells is reflected by a cease to periodic signal intensity
fluctuations. Meanwhile, ex situ 23Na NMR spectra of the deactivated cells reveal
a complex range of environments for sodium ions.
author:
- first_name: Sonja
full_name: Egert, Sonja
last_name: Egert
- first_name: Renuka
full_name: Remesh, Renuka
last_name: Remesh
- first_name: Agatha Clarissa
full_name: Jusdi, Agatha Clarissa
last_name: Jusdi
- first_name: Yushi
full_name: Sugawara, Yushi
last_name: Sugawara
- first_name: Konstantin
full_name: Schutjajew, Konstantin
last_name: Schutjajew
- 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: Egert S, Remesh R, Jusdi AC, et al. Long-Term Cycling Stability of Sodium/Sodium
Ion Cells Probed by In Situ Solid-State NMR Spectroscopy. Batteries & Supercaps.
2025;n/a(n/a):e202500516. doi:10.1002/batt.202500516
apa: Egert, S., Remesh, R., Jusdi, A. C., Sugawara, Y., Schutjajew, K., Oschatz,
M., Buntkowsky, G., & Gutmann, T. (2025). Long-Term Cycling Stability of Sodium/Sodium
Ion Cells Probed by In Situ Solid-State NMR Spectroscopy. Batteries & Supercaps,
n/a(n/a), e202500516. https://doi.org/10.1002/batt.202500516
bibtex: '@article{Egert_Remesh_Jusdi_Sugawara_Schutjajew_Oschatz_Buntkowsky_Gutmann_2025,
title={Long-Term Cycling Stability of Sodium/Sodium Ion Cells Probed by In Situ
Solid-State NMR Spectroscopy}, volume={n/a}, DOI={10.1002/batt.202500516},
number={n/a}, journal={Batteries & Supercaps}, publisher={John Wiley &
Sons, Ltd}, author={Egert, Sonja and Remesh, Renuka and Jusdi, Agatha Clarissa
and Sugawara, Yushi and Schutjajew, Konstantin and Oschatz, Martin and Buntkowsky,
Gerd and Gutmann, Torsten}, year={2025}, pages={e202500516} }'
chicago: 'Egert, Sonja, Renuka Remesh, Agatha Clarissa Jusdi, Yushi Sugawara, Konstantin
Schutjajew, Martin Oschatz, Gerd Buntkowsky, and Torsten Gutmann. “Long-Term Cycling
Stability of Sodium/Sodium Ion Cells Probed by In Situ Solid-State NMR Spectroscopy.”
Batteries & Supercaps n/a, no. n/a (2025): e202500516. https://doi.org/10.1002/batt.202500516.'
ieee: 'S. Egert et al., “Long-Term Cycling Stability of Sodium/Sodium Ion
Cells Probed by In Situ Solid-State NMR Spectroscopy,” Batteries & Supercaps,
vol. n/a, no. n/a, p. e202500516, 2025, doi: 10.1002/batt.202500516.'
mla: Egert, Sonja, et al. “Long-Term Cycling Stability of Sodium/Sodium Ion Cells
Probed by In Situ Solid-State NMR Spectroscopy.” Batteries & Supercaps,
vol. n/a, no. n/a, John Wiley & Sons, Ltd, 2025, p. e202500516, doi:10.1002/batt.202500516.
short: S. Egert, R. Remesh, A.C. Jusdi, Y. Sugawara, K. Schutjajew, M. Oschatz,
G. Buntkowsky, T. Gutmann, Batteries & Supercaps n/a (2025) e202500516.
date_created: 2026-02-07T09:13:59Z
date_updated: 2026-02-17T16:18:23Z
doi: 10.1002/batt.202500516
extern: '1'
issue: n/a
keyword:
- solid-state nmr
- hard carbon
- in-situ
- SiCN
- sodium ion batteries
language:
- iso: eng
page: e202500516
publication: Batteries & Supercaps
publisher: John Wiley & Sons, Ltd
status: public
title: Long-Term Cycling Stability of Sodium/Sodium Ion Cells Probed by In Situ Solid-State
NMR Spectroscopy
type: journal_article
user_id: '100715'
volume: n/a
year: '2025'
...
---
_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: '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: '63948'
abstract:
- lang: eng
text: In this work, the behavior of four different commercially available polarizing
agents is investigated employing the non-ionic model surfactant 1-octanol as analyte.
A relative method for the comparison of the proportion of the direct and indirect
polarization transfer pathways is established, allowing a direct comparison of
the polarization efficacy for different radicals and different parts of the 1-octanol
molecule despite differences in radical concentration or sample amount. With this
approach, it could be demonstrated that the hydrophilicity is a key factor in
the way polarization is transferred from the polarizing agent to the analyte.
These findings are confirmed by the determination of buildup times Tb, illustrating
that the choice of polarizing agent plays an essential role in ensuring an optimal
polarization transfer and therefore the maximum amount of enhancement possible
for DNP enhanced NMR measurements.
author:
- first_name: Sonja C.
full_name: Döller, Sonja C.
last_name: Döller
- 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, Gutmann T, Hoffmann M, Buntkowsky G. A case study on the influence
of hydrophilicity on the signal enhancement by dynamic nuclear polarization. Solid
State Nuclear Magnetic Resonance. 2022;122:101829.
apa: Döller, S. C., Gutmann, T., Hoffmann, M., & Buntkowsky, G. (2022). A case
study on the influence of hydrophilicity on the signal enhancement by dynamic
nuclear polarization. Solid State Nuclear Magnetic Resonance, 122,
101829.
bibtex: '@article{Döller_Gutmann_Hoffmann_Buntkowsky_2022, title={A case study on
the influence of hydrophilicity on the signal enhancement by dynamic nuclear polarization},
volume={122}, journal={Solid State Nuclear Magnetic Resonance}, author={Döller,
Sonja C. and Gutmann, Torsten and Hoffmann, Markus and Buntkowsky, Gerd}, year={2022},
pages={101829} }'
chicago: 'Döller, Sonja C., Torsten Gutmann, Markus Hoffmann, and Gerd Buntkowsky.
“A Case Study on the Influence of Hydrophilicity on the Signal Enhancement by
Dynamic Nuclear Polarization.” Solid State Nuclear Magnetic Resonance 122
(2022): 101829.'
ieee: S. C. Döller, T. Gutmann, M. Hoffmann, and G. Buntkowsky, “A case study on
the influence of hydrophilicity on the signal enhancement by dynamic nuclear polarization,”
Solid State Nuclear Magnetic Resonance, vol. 122, p. 101829, 2022.
mla: Döller, Sonja C., et al. “A Case Study on the Influence of Hydrophilicity on
the Signal Enhancement by Dynamic Nuclear Polarization.” Solid State Nuclear
Magnetic Resonance, vol. 122, 2022, p. 101829.
short: S.C. Döller, T. Gutmann, M. Hoffmann, G. Buntkowsky, Solid State Nuclear
Magnetic Resonance 122 (2022) 101829.
date_created: 2026-02-07T09:13:08Z
date_updated: 2026-02-17T16:18:26Z
extern: '1'
intvolume: ' 122'
keyword:
- DNP NMR
- Dynamics
- Low temperature NMR
- Octanol
- Solid state NMR
- Surfactants
language:
- iso: eng
page: '101829'
publication: Solid State Nuclear Magnetic Resonance
status: public
title: A case study on the influence of hydrophilicity on the signal enhancement by
dynamic nuclear polarization
type: journal_article
user_id: '100715'
volume: 122
year: '2022'
...
---
_id: '63943'
abstract:
- lang: eng
text: A lithium halide exchange reaction at low-temperature, via the treatment of
2,6-di(isopropyl)phenyllithium on 1,1′-bis-(dichlorophosphino)ferrocene, resulted
in the first isolated example of an aryl-substituted diphospha [2]ferrocenophane
(diphospha [2]FCP) 2. Although compound 2 did not show any recognizable thermal
reaction at higher temperature (up to 350 °C), its tert-butyl-substituted counterpart
1 underwent a clean selective heat-mediated P–C cleavage reaction, followed
by an inter-molecular rearrangement, to produce a P–P fused bis [3]ferrocenophane
3 with all-trans oriented P-chain, which upon further heating gave a polyferrocenylphosphane
tBu-[Fc’P2]n-tBu (4). Since polymer 4 is insoluble in common organic solvents,
it has been characterized with solid-state techniques, including solid-state NMR.
Density functional theory (DFT) has further been employed to identify possible
pathways for P–C bond cleavage on 1 and 2, as well as to evaluate accessible
pathways for further polymerization toward 4.
author:
- first_name: Subhayan
full_name: Dey, Subhayan
last_name: Dey
- first_name: Denis
full_name: Kargin, Denis
last_name: Kargin
- first_name: Mark V.
full_name: Höfler, Mark V.
last_name: Höfler
- first_name: Balazs
full_name: Szathmari, Balazs
last_name: Szathmari
- first_name: Clemens
full_name: Bruhn, Clemens
last_name: Bruhn
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
- first_name: Zsolt
full_name: Kelemen, Zsolt
last_name: Kelemen
- first_name: Rudolf
full_name: Pietschnig, Rudolf
last_name: Pietschnig
citation:
ama: Dey S, Kargin D, Höfler MV, et al. Oligo- and polymerization of phospha [2]ferrocenophanes
to one dimensional phosphorus chains with ferrocenylene handles. Polymer.
2022;242:124589.
apa: Dey, S., Kargin, D., Höfler, M. V., Szathmari, B., Bruhn, C., Gutmann, T.,
Kelemen, Z., & Pietschnig, R. (2022). Oligo- and polymerization of phospha
[2]ferrocenophanes to one dimensional phosphorus chains with ferrocenylene handles.
Polymer, 242, 124589.
bibtex: '@article{Dey_Kargin_Höfler_Szathmari_Bruhn_Gutmann_Kelemen_Pietschnig_2022,
title={Oligo- and polymerization of phospha [2]ferrocenophanes to one dimensional
phosphorus chains with ferrocenylene handles}, volume={242}, journal={Polymer},
author={Dey, Subhayan and Kargin, Denis and Höfler, Mark V. and Szathmari, Balazs
and Bruhn, Clemens and Gutmann, Torsten and Kelemen, Zsolt and Pietschnig, Rudolf},
year={2022}, pages={124589} }'
chicago: 'Dey, Subhayan, Denis Kargin, Mark V. Höfler, Balazs Szathmari, Clemens
Bruhn, Torsten Gutmann, Zsolt Kelemen, and Rudolf Pietschnig. “Oligo- and Polymerization
of Phospha [2]Ferrocenophanes to One Dimensional Phosphorus Chains with Ferrocenylene
Handles.” Polymer 242 (2022): 124589.'
ieee: S. Dey et al., “Oligo- and polymerization of phospha [2]ferrocenophanes
to one dimensional phosphorus chains with ferrocenylene handles,” Polymer,
vol. 242, p. 124589, 2022.
mla: Dey, Subhayan, et al. “Oligo- and Polymerization of Phospha [2]Ferrocenophanes
to One Dimensional Phosphorus Chains with Ferrocenylene Handles.” Polymer,
vol. 242, 2022, p. 124589.
short: S. Dey, D. Kargin, M.V. Höfler, B. Szathmari, C. Bruhn, T. Gutmann, Z. Kelemen,
R. Pietschnig, Polymer 242 (2022) 124589.
date_created: 2026-02-07T09:10:38Z
date_updated: 2026-02-17T16:18:36Z
extern: '1'
intvolume: ' 242'
keyword:
- solid-state nmr
- Ansa-ferrocene
- DFT calculations
- Oligophosphine
- Polyphosphane
- Ring-opening polymerization
language:
- iso: eng
page: '124589'
publication: Polymer
status: public
title: Oligo- and polymerization of phospha [2]ferrocenophanes to one dimensional
phosphorus chains with ferrocenylene handles
type: journal_article
user_id: '100715'
volume: 242
year: '2022'
...
---
_id: '64018'
abstract:
- lang: eng
text: CO oxidation is an extensively studied reaction in heterogeneous catalysis
due to its seeming simplicity and its great importance for emission control. However,
the role of particle size and more specifically structure sensitivity in this
reaction is still controversial. In the present study, colloidal “surfactant-free”
Pt nanoparticles (NPs) in a size regime of 1–4 nm with narrow size distribution
and control over particle size were synthesized and subsequently supported on
Al2O3 to prepare model catalysts. CO oxidation was performed using Pt NPs catalysts
with particles sizes of 1, 2, 3, and 4 nm at different reaction temperatures.
It is shown that the reaction exhibits a particle size effect that depends strongly
on the reaction conditions. At 170 °C, the reaction seems to proceed within the
same kinetic regime for all particle sizes, but the surface normalized activity
depends strongly on the particle size, with maximum activity for nanoparticles
2 nm in diameter. A temperature increase to 200 °C leads to a change of the kinetic
regime that depends on the particle size. For Pt NPs 1 nm in diameter a reaction
order of 1 for O2 was observed, indicating that O2 adsorbs molecularly and dissociates
in a following step, which represents the generally accepted mechanism on Pt surfaces.
The reaction order of −1 for CO demonstrates that the surface is saturated with
CO under reaction conditions. With increasing particle size, the reaction orders
of O2 and CO change. For particles 2 nm in size, an increase in temperature also
results in reaction orders of 1 for O2 and −1 for CO; NPs of 3 and 4 nm, even
at higher temperatures, show no clear kinetic behavior that can be explained by
a single reaction mechanism. Instead, the Boudouard reaction between two adjacent
adsorbed CO molecules was identified as an important additional reaction pathway
that occurs preferentially on large particles and causes more complex kinetics.
author:
- first_name: Sarah
full_name: Neumann, Sarah
last_name: Neumann
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
- first_name: Gerd
full_name: Buntkowsky, Gerd
last_name: Buntkowsky
- first_name: Stephen
full_name: Paul, Stephen
last_name: Paul
- first_name: Greg
full_name: Thiele, Greg
last_name: Thiele
- first_name: Heiko
full_name: Sievers, Heiko
last_name: Sievers
- first_name: Marcus
full_name: Bäumer, Marcus
last_name: Bäumer
- first_name: Sebastian
full_name: Kunz, Sebastian
last_name: Kunz
citation:
ama: Neumann S, Gutmann T, Buntkowsky G, et al. Insights into the reaction mechanism
and particle size effects of CO oxidation over supported Pt nanoparticle catalysts.
Journal of Catalysis. 2019;377:662–672. doi:10.1016/j.jcat.2019.07.049
apa: Neumann, S., Gutmann, T., Buntkowsky, G., Paul, S., Thiele, G., Sievers, H.,
Bäumer, M., & Kunz, S. (2019). Insights into the reaction mechanism and particle
size effects of CO oxidation over supported Pt nanoparticle catalysts. Journal
of Catalysis, 377, 662–672. https://doi.org/10.1016/j.jcat.2019.07.049
bibtex: '@article{Neumann_Gutmann_Buntkowsky_Paul_Thiele_Sievers_Bäumer_Kunz_2019,
title={Insights into the reaction mechanism and particle size effects of CO oxidation
over supported Pt nanoparticle catalysts}, volume={377}, DOI={10.1016/j.jcat.2019.07.049},
journal={Journal of Catalysis}, author={Neumann, Sarah and Gutmann, Torsten and
Buntkowsky, Gerd and Paul, Stephen and Thiele, Greg and Sievers, Heiko and Bäumer,
Marcus and Kunz, Sebastian}, year={2019}, pages={662–672} }'
chicago: 'Neumann, Sarah, Torsten Gutmann, Gerd Buntkowsky, Stephen Paul, Greg Thiele,
Heiko Sievers, Marcus Bäumer, and Sebastian Kunz. “Insights into the Reaction
Mechanism and Particle Size Effects of CO Oxidation over Supported Pt Nanoparticle
Catalysts.” Journal of Catalysis 377 (2019): 662–672. https://doi.org/10.1016/j.jcat.2019.07.049.'
ieee: 'S. Neumann et al., “Insights into the reaction mechanism and particle
size effects of CO oxidation over supported Pt nanoparticle catalysts,” Journal
of Catalysis, vol. 377, pp. 662–672, 2019, doi: 10.1016/j.jcat.2019.07.049.'
mla: Neumann, Sarah, et al. “Insights into the Reaction Mechanism and Particle Size
Effects of CO Oxidation over Supported Pt Nanoparticle Catalysts.” Journal
of Catalysis, vol. 377, 2019, pp. 662–672, doi:10.1016/j.jcat.2019.07.049.
short: S. Neumann, T. Gutmann, G. Buntkowsky, S. Paul, G. Thiele, H. Sievers, M.
Bäumer, S. Kunz, Journal of Catalysis 377 (2019) 662–672.
date_created: 2026-02-07T16:02:06Z
date_updated: 2026-02-17T16:14:45Z
doi: 10.1016/j.jcat.2019.07.049
extern: '1'
intvolume: ' 377'
keyword:
- Solid state NMR
- “Surfactant-free” platinum nanoparticles
- CO oxidation
- Particle size effect
- Structure sensitivity
language:
- iso: eng
page: 662–672
publication: Journal of Catalysis
status: public
title: Insights into the reaction mechanism and particle size effects of CO oxidation
over supported Pt nanoparticle catalysts
type: journal_article
user_id: '100715'
volume: 377
year: '2019'
...
---
_id: '63960'
abstract:
- lang: eng
text: Recent advances in solid-state nuclear magnetic resonance (NMR) spectroscopy
and dynamic nuclear polarization (DNP) of nanostructured materials are reviewed.
A first group of materials is based on crystalline nanocellulose (CNC) or microcrystalline
cellulose (MCC), which are used as carrier materials for dye molecules, catalysts
or in combination with heterocyclic molecules as ion conducting membranes. These
materials have widespread applications in sensorics, optics, catalysis or fuel
cell research. A second group are metal oxides such as V-Mo-W oxides, which are
of enormous importance in the manufacturing process of basic chemicals. The third
group are catalytically active nanocrystalline metal nanoparticles, coated with
protectants or embedded in polymers. The last group includes of lead-free perovskite
materials, which are employed as environmentally benign substitution materials
for conventional lead-based electronics materials. These materials are discussed
in terms of their application and physico-chemical characterization by solid-state
NMR techniques, combined with gas-phase NMR and quantum-chemical modelling on
the density functional theory (DFT) level. The application of multinuclear 1H,
2H, 13C, 15N and 23Na solid state NMR techniques under static or MAS conditions
for the characterization of these materials, their surfaces and processes on their
surfaces is discussed. Moreover, the analytic power of the combination of these
techniques with DNP for the identification of low-concentrated carbon and nitrogen
containing surface species in natural abundance is reviewed. Finally, approaches
for sensitivity enhancement by DNP of quadrupolar nuclei such as 17O and 51V are
presented that enable the identification of catalytic sites in metal oxide catalysts.
author:
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
- first_name: Pedro B.
full_name: Groszewicz, Pedro B.
last_name: Groszewicz
- first_name: Gerd
full_name: Buntkowsky, Gerd
last_name: Buntkowsky
citation:
ama: Gutmann T, Groszewicz PB, Buntkowsky G. Solid-state NMR of nanocrystals. Annual
Reports on NMR Spectroscopy. 2019;97:1–82. doi:10.1016/bs.arnmr.2018.12.001
apa: Gutmann, T., Groszewicz, P. B., & Buntkowsky, G. (2019). Solid-state NMR
of nanocrystals. Annual Reports on NMR Spectroscopy, 97, 1–82. https://doi.org/10.1016/bs.arnmr.2018.12.001
bibtex: '@article{Gutmann_Groszewicz_Buntkowsky_2019, title={Solid-state NMR of
nanocrystals}, volume={97}, DOI={10.1016/bs.arnmr.2018.12.001},
journal={Annual Reports on NMR Spectroscopy}, author={Gutmann, Torsten and Groszewicz,
Pedro B. and Buntkowsky, Gerd}, year={2019}, pages={1–82} }'
chicago: 'Gutmann, Torsten, Pedro B. Groszewicz, and Gerd Buntkowsky. “Solid-State
NMR of Nanocrystals.” Annual Reports on NMR Spectroscopy 97 (2019): 1–82.
https://doi.org/10.1016/bs.arnmr.2018.12.001.'
ieee: 'T. Gutmann, P. B. Groszewicz, and G. Buntkowsky, “Solid-state NMR of nanocrystals,”
Annual Reports on NMR Spectroscopy, vol. 97, pp. 1–82, 2019, doi: 10.1016/bs.arnmr.2018.12.001.'
mla: Gutmann, Torsten, et al. “Solid-State NMR of Nanocrystals.” Annual Reports
on NMR Spectroscopy, vol. 97, 2019, pp. 1–82, doi:10.1016/bs.arnmr.2018.12.001.
short: T. Gutmann, P.B. Groszewicz, G. Buntkowsky, Annual Reports on NMR Spectroscopy
97 (2019) 1–82.
date_created: 2026-02-07T15:37:03Z
date_updated: 2026-02-17T16:17:56Z
doi: 10.1016/bs.arnmr.2018.12.001
extern: '1'
intvolume: ' 97'
keyword:
- solid-state nmr
- heterogeneous catalysis
- dynamic nuclear polarization
- Ferroelectrics
- Nanocatalysis
- Surface reactions
language:
- iso: eng
page: 1–82
publication: Annual Reports on NMR Spectroscopy
status: public
title: Solid-state NMR of nanocrystals
type: journal_article
user_id: '100715'
volume: 97
year: '2019'
...
---
_id: '64053'
abstract:
- lang: eng
text: The utilization and preparation of functional hybrid films for optical sensing
applications and membranes is of utmost importance. In this work, we report the
convenient and scalable preparation of self-crosslinking particle-based films
derived by directed self-assembly of alkoxysilane-based cross-linkers as part
of a core-shell particle architecture. The synthesis of well-designed monodisperse
core-shell particles by emulsion polymerization is the basic prerequisite for
subsequent particle processing via the melt-shear organization technique. In more
detail, the core particles consist of polystyrene (PS) or poly(methyl methacrylate)
(PMMA), while the comparably soft particle shell consists of poly(ethyl acrylate)
(PEA) and different alkoxysilane-based poly(methacrylate)s. For hybrid film formation
and convenient self-cross-linking, different alkyl groups at the siloxane moieties
were investigated in detail by solid-state Magic-Angle Spinning Nuclear Magnetic
Resonance (MAS, NMR) spectroscopy revealing different crosslinking capabilities,
which strongly influence the properties of the core or shell particle films with
respect to transparency and iridescent reflection colors. Furthermore, solid-state
NMR spectroscopy and investigation of the thermal properties by differential scanning
calorimetry (DSC) measurements allow for insights into the cross-linking capabilities
prior to and after synthesis, as well as after the thermally and pressure-induced
processing steps. Subsequently, free-standing and self-crosslinked particle-based
films featuring excellent particle order are obtained by application of the melt-shear
organization technique, as shown by microscopy (TEM, SEM).
author:
- first_name: S.
full_name: Vowinkel, S.
last_name: Vowinkel
- first_name: S.
full_name: Paul, S.
last_name: Paul
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
- first_name: M.
full_name: Gallei, M.
last_name: Gallei
citation:
ama: Vowinkel S, Paul S, Gutmann T, Gallei M. Free-Standing and Self-Crosslinkable
Hybrid Films by Core-Shell Particle Design and Processing. Nanomaterials.
2017;7(11):390. doi:10.3390/nano7110390
apa: Vowinkel, S., Paul, S., Gutmann, T., & Gallei, M. (2017). Free-Standing
and Self-Crosslinkable Hybrid Films by Core-Shell Particle Design and Processing.
Nanomaterials, 7(11), 390. https://doi.org/10.3390/nano7110390
bibtex: '@article{Vowinkel_Paul_Gutmann_Gallei_2017, title={Free-Standing and Self-Crosslinkable
Hybrid Films by Core-Shell Particle Design and Processing}, volume={7}, DOI={10.3390/nano7110390}, number={11},
journal={Nanomaterials}, author={Vowinkel, S. and Paul, S. and Gutmann, Torsten
and Gallei, M.}, year={2017}, pages={390} }'
chicago: 'Vowinkel, S., S. Paul, Torsten Gutmann, and M. Gallei. “Free-Standing
and Self-Crosslinkable Hybrid Films by Core-Shell Particle Design and Processing.”
Nanomaterials 7, no. 11 (2017): 390. https://doi.org/10.3390/nano7110390.'
ieee: 'S. Vowinkel, S. Paul, T. Gutmann, and M. Gallei, “Free-Standing and Self-Crosslinkable
Hybrid Films by Core-Shell Particle Design and Processing,” Nanomaterials,
vol. 7, no. 11, p. 390, 2017, doi: 10.3390/nano7110390.'
mla: Vowinkel, S., et al. “Free-Standing and Self-Crosslinkable Hybrid Films by
Core-Shell Particle Design and Processing.” Nanomaterials, vol. 7, no.
11, 2017, p. 390, doi:10.3390/nano7110390.
short: S. Vowinkel, S. Paul, T. Gutmann, M. Gallei, Nanomaterials 7 (2017) 390.
date_created: 2026-02-07T16:15:23Z
date_updated: 2026-02-17T16:12:54Z
doi: 10.3390/nano7110390
extern: '1'
intvolume: ' 7'
issue: '11'
keyword:
- Materials Science
- Science & Technology - Other Topics
- solid-state nmr
- spectroscopy
- catalysts
- colloidal crystals
- colloids
- cross-linking
- elastomeric opal films
- emulsion polymerization
- gamma-methacryloxypropyltrimethoxysilane
- hybrid films
- melt-shear organization
- nanoparticles
- particle
- photons
- polymers
- processing
- self-assembly
- transition
language:
- iso: eng
page: '390'
publication: Nanomaterials
publication_identifier:
issn:
- 2079-4991
status: public
title: Free-Standing and Self-Crosslinkable Hybrid Films by Core-Shell Particle Design
and Processing
type: journal_article
user_id: '100715'
volume: 7
year: '2017'
...
---
_id: '63956'
abstract:
- lang: eng
text: The synthesis of novel robust and stable iridium-based immobilized catalysts
on silica-polymer hybrid materials (Si-PB-Ir) is described. These catalysts are
characterized by a combination of 1D P-31 CP-MAS and 2D P-31-H-1 HETCOR and J-resolved
multinuclear solid state NMR experiments. Different binding situations such as
singly and multiply coordinated phosphines are identified. Density functional
theory (DFT) calculations are performed to corroborate the interpretation of the
experimental NMR data, in order to propose a structural model of the heterogenized
catalysts. Finally, the catalytic activity of the Si-PB-Ir catalysts is investigated
for the hydrogenation of styrene employing para-enriched hydrogen gas.
author:
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
- first_name: S.
full_name: Alkhagani, S.
last_name: Alkhagani
- first_name: N.
full_name: Rothermel, N.
last_name: Rothermel
- first_name: H. H.
full_name: Limbach, H. H.
last_name: Limbach
- first_name: H.
full_name: Breitzke, H.
last_name: Breitzke
- first_name: G.
full_name: Buntkowsky, G.
last_name: Buntkowsky
citation:
ama: Gutmann T, Alkhagani S, Rothermel N, Limbach HH, Breitzke H, Buntkowsky G.
P-31-Solid-State NMR Characterization and Catalytic Hydrogenation Tests of Novel
heterogenized Iridium-Catalysts. Zeitschrift Fur Physikalische Chemie-International
Journal of Research in Physical Chemistry & Chemical Physics. 2017;231(3):653–669.
doi:10.1515/zpch-2016-0837
apa: Gutmann, T., Alkhagani, S., Rothermel, N., Limbach, H. H., Breitzke, H., &
Buntkowsky, G. (2017). P-31-Solid-State NMR Characterization and Catalytic Hydrogenation
Tests of Novel heterogenized Iridium-Catalysts. Zeitschrift Fur Physikalische
Chemie-International Journal of Research in Physical Chemistry & Chemical
Physics, 231(3), 653–669. https://doi.org/10.1515/zpch-2016-0837
bibtex: '@article{Gutmann_Alkhagani_Rothermel_Limbach_Breitzke_Buntkowsky_2017,
title={P-31-Solid-State NMR Characterization and Catalytic Hydrogenation Tests
of Novel heterogenized Iridium-Catalysts}, volume={231}, DOI={10.1515/zpch-2016-0837},
number={3}, journal={Zeitschrift Fur Physikalische Chemie-International Journal
of Research in Physical Chemistry & Chemical Physics}, author={Gutmann, Torsten
and Alkhagani, S. and Rothermel, N. and Limbach, H. H. and Breitzke, H. and Buntkowsky,
G.}, year={2017}, pages={653–669} }'
chicago: 'Gutmann, Torsten, S. Alkhagani, N. Rothermel, H. H. Limbach, H. Breitzke,
and G. Buntkowsky. “P-31-Solid-State NMR Characterization and Catalytic Hydrogenation
Tests of Novel Heterogenized Iridium-Catalysts.” Zeitschrift Fur Physikalische
Chemie-International Journal of Research in Physical Chemistry & Chemical
Physics 231, no. 3 (2017): 653–669. https://doi.org/10.1515/zpch-2016-0837.'
ieee: 'T. Gutmann, S. Alkhagani, N. Rothermel, H. H. Limbach, H. Breitzke, and G.
Buntkowsky, “P-31-Solid-State NMR Characterization and Catalytic Hydrogenation
Tests of Novel heterogenized Iridium-Catalysts,” Zeitschrift Fur Physikalische
Chemie-International Journal of Research in Physical Chemistry & Chemical
Physics, vol. 231, no. 3, pp. 653–669, 2017, doi: 10.1515/zpch-2016-0837.'
mla: Gutmann, Torsten, et al. “P-31-Solid-State NMR Characterization and Catalytic
Hydrogenation Tests of Novel Heterogenized Iridium-Catalysts.” Zeitschrift
Fur Physikalische Chemie-International Journal of Research in Physical Chemistry
& Chemical Physics, vol. 231, no. 3, 2017, pp. 653–669, doi:10.1515/zpch-2016-0837.
short: T. Gutmann, S. Alkhagani, N. Rothermel, H.H. Limbach, H. Breitzke, G. Buntkowsky,
Zeitschrift Fur Physikalische Chemie-International Journal of Research in Physical
Chemistry & Chemical Physics 231 (2017) 653–669.
date_created: 2026-02-07T15:35:41Z
date_updated: 2026-02-17T16:18:04Z
doi: 10.1515/zpch-2016-0837
extern: '1'
intvolume: ' 231'
issue: '3'
keyword:
- Chemistry
- dynamic nuclear-polarization
- solid-state nmr
- DFT
- heterogeneous catalysis
- hydrido complexes
- hydrogenation
- immobilized catalyst
- inorganic hybrid
- iridium
- materials
- mesoporous
- molecular-orbital methods
- PHIP
- phosphine complexes
- reusable catalysts
- silica
- solid-state-NMR
- wilkinsons catalyst
language:
- iso: eng
page: 653–669
publication: Zeitschrift Fur Physikalische Chemie-International Journal of Research
in Physical Chemistry & Chemical Physics
publication_identifier:
issn:
- 0942-9352
status: public
title: P-31-Solid-State NMR Characterization and Catalytic Hydrogenation Tests of
Novel heterogenized Iridium-Catalysts
type: journal_article
user_id: '100715'
volume: 231
year: '2017'
...
---
_id: '63920'
abstract:
- lang: eng
text: Coordinatively unsaturated sites (CUS) present a key feature of alumina based
catalysts as they are believed to act as Lewis-acid sites in heterogeneously catalyzed
reactions. In the present study, the direct observation of active species on a
fluoride-doped aluminum oxide catalyst is demonstrated. This new fluoride-doped
aluminum oxide exhibits strong Lewis-acid sites and superior catalytic activity
as compared to gamma-Al2O3. To emphasize the labile state of Lewis-acid sites,
two distinctive states of the catalysts surface are addressed using H-1-Al-27
cross polarization (CP) MAS NMR. On the one hand, the highly dehydrated and active
state after calcination at 700 degrees C and on the other hand the rehydrated
and catalytically inactive surface (produced by contact to air) are probed. These
experiments revealed the presence of significant amounts of coordinatively unsaturated
sites in the form of 4-and 5-fold coordinated Al-sites on the highly dehydrated
surface. In contrast to this, the rehydrated sample exhibited a severely restructured
surface caused by the chemisorption of H2O which is ’constituted in a manner that
was proposed in earlier models for gamma-Al2O3 surfaces.
author:
- first_name: L.
full_name: Ahrem, L.
last_name: Ahrem
- first_name: G.
full_name: Scholz, G.
last_name: Scholz
- first_name: Torsten
full_name: Gutmann, Torsten
id: '118165'
last_name: Gutmann
- first_name: B.
full_name: Calvo, B.
last_name: Calvo
- first_name: G.
full_name: Buntkowsky, G.
last_name: Buntkowsky
- first_name: E.
full_name: Kemnitz, E.
last_name: Kemnitz
citation:
ama: Ahrem L, Scholz G, Gutmann T, Calvo B, Buntkowsky G, Kemnitz E. Direct Observation
of Coordinatively Unsaturated Sites on the Surface of a Fluoride-Doped Alumina
Catalyst. Journal of Physical Chemistry C. 2017;121(22):12206–12213. doi:10.1021/acs.jpcc.7b02535
apa: Ahrem, L., Scholz, G., Gutmann, T., Calvo, B., Buntkowsky, G., & Kemnitz,
E. (2017). Direct Observation of Coordinatively Unsaturated Sites on the Surface
of a Fluoride-Doped Alumina Catalyst. Journal of Physical Chemistry C,
121(22), 12206–12213. https://doi.org/10.1021/acs.jpcc.7b02535
bibtex: '@article{Ahrem_Scholz_Gutmann_Calvo_Buntkowsky_Kemnitz_2017, title={Direct
Observation of Coordinatively Unsaturated Sites on the Surface of a Fluoride-Doped
Alumina Catalyst}, volume={121}, DOI={10.1021/acs.jpcc.7b02535},
number={22}, journal={Journal of Physical Chemistry C}, author={Ahrem, L. and
Scholz, G. and Gutmann, Torsten and Calvo, B. and Buntkowsky, G. and Kemnitz,
E.}, year={2017}, pages={12206–12213} }'
chicago: 'Ahrem, L., G. Scholz, Torsten Gutmann, B. Calvo, G. Buntkowsky, and E.
Kemnitz. “Direct Observation of Coordinatively Unsaturated Sites on the Surface
of a Fluoride-Doped Alumina Catalyst.” Journal of Physical Chemistry C
121, no. 22 (2017): 12206–12213. https://doi.org/10.1021/acs.jpcc.7b02535.'
ieee: 'L. Ahrem, G. Scholz, T. Gutmann, B. Calvo, G. Buntkowsky, and E. Kemnitz,
“Direct Observation of Coordinatively Unsaturated Sites on the Surface of a Fluoride-Doped
Alumina Catalyst,” Journal of Physical Chemistry C, vol. 121, no. 22, pp.
12206–12213, 2017, doi: 10.1021/acs.jpcc.7b02535.'
mla: Ahrem, L., et al. “Direct Observation of Coordinatively Unsaturated Sites on
the Surface of a Fluoride-Doped Alumina Catalyst.” Journal of Physical Chemistry
C, vol. 121, no. 22, 2017, pp. 12206–12213, doi:10.1021/acs.jpcc.7b02535.
short: L. Ahrem, G. Scholz, T. Gutmann, B. Calvo, G. Buntkowsky, E. Kemnitz, Journal
of Physical Chemistry C 121 (2017) 12206–12213.
date_created: 2026-02-07T08:56:18Z
date_updated: 2026-02-17T16:19:24Z
doi: 10.1021/acs.jpcc.7b02535
extern: '1'
intvolume: ' 121'
issue: '22'
keyword:
- al-27 nmr
- characterization
- Chemistry
- cross-polarization
- dynamic nuclear-polarization
- eta-alumina
- gamma-alumina
- hydroxy fluorides
- ions
- Materials Science
- pentacoordinated al3+
- Science & Technology - Other Topics
- solid-state nmr
- spectroscopic
- structural insights
language:
- iso: eng
page: 12206–12213
publication: Journal of Physical Chemistry C
publication_identifier:
issn:
- 1932-7447
status: public
title: Direct Observation of Coordinatively Unsaturated Sites on the Surface of a
Fluoride-Doped Alumina Catalyst
type: journal_article
user_id: '100715'
volume: 121
year: '2017'
...