Variable-Temperature Solid-State NMR Spectroscopy

1988 ◽  
Vol 60 (9) ◽  
pp. 559A-570A ◽  
Author(s):  
James F. Haw
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Variable Temperature ◽  
Solid State Nmr Spectroscopy

Assessing distortion of the AF 6 − (A=As, Sb) octahedra in solid hexafluorometallates(V) via NMR spectroscopy

2015 ◽  
Vol 93 (9) ◽  
pp. 938-944 ◽  
Author(s):  
Alexandra Faucher ◽  
Victor V. Terskikh ◽  
Roderick E. Wasylishen
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Solid Phase ◽  
Variable Temperature ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Cubic Phase ◽  
Solid State Nmr Spectroscopy ◽  
Higher Temperature

Arsenic and antimony hexafluoride salts have played an important role in the history of both solution and solid-state NMR spectroscopy. Here, solid polycrystalline KAsF6 and KSbF6 have been studied via high-resolution variable temperature 19F, 75As, 121Sb, and 123Sb solid-state NMR spectroscopy at high magnetic field (B0 = 21.14 T). Both KAsF6 and KSbF6 undergo solid-solid phase transitions at approximately 375 and 301 K, respectively. We use variable temperature NMR experiments to explore the effects of crystal structure changes on NMR parameters. CQ(75As) values for KAsF6 at 293, 323, and 348 K are −2.87 ± 0.05 MHz, −2.58 ± 0.05 MHz, and −2.30 ± 0.05 MHz, respectively, the sign determined via DFT calculations. In the higher temperature cubic phase, CQ(75As) = 0 Hz, consistent with the crystal symmetry at the arsenic nucleus in this phase. In contrast, CQ values for 121Sb and 123Sb in the cubic phase of KSbF6 are nonzero. E.g., at 293 K, CQ(121Sb) = 6.42 ± 0.10 MHz, and CQ(123Sb) = 8.22 ± 0.10 MHz. In the higher temperature tetragonal phase (343 K) of KSbF6, these values are 3.11 ± 0.20 MHz and 4.06 ± 0.20 MHz, respectively. CASTEP calculations performed on the cubic and tetragonal structures support this trend. Isotropic indirect spin-spin coupling constants are 1J(75As,19F) = −926 ± 10 Hz (293 K) and −926 ± 3 Hz (348 K), and 1J(121Sb,19F) = −1884 ± 3 Hz (293 K), and −1889 ± 3 Hz (343 K). Arsenic-75 and antimony-121,123 chemical shift values show little variation over the studied temperature ranges.

ChemInform Abstract: Reactions of Propene on Zeolite HY Catalyst Studied by in situ Variable-Temperature Solid-State NMR Spectroscopy.

ChemInform ◽  
1989 ◽  
Vol 20 (26) ◽  
Author(s):  
J. F. HAW ◽  
B. R. RICHARDSON ◽  
I. S. OSHIRO ◽  
N. D. LAZO ◽  
J. A. SPEED
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Variable Temperature ◽  
Solid State Nmr Spectroscopy

scholarly journals A New Methodological Approach to Correlate Protective and Microscopic Properties by Soft X-ray Microscopy and Solid State NMR Spectroscopy: The Case of Cusa’s Stone

2021 ◽  
Vol 11 (13) ◽  
pp. 5767
Author(s):  
Veronica Ciaramitaro ◽  
Alberto Spinella ◽  
Francesco Armetta ◽  
Roberto Scaffaro ◽  
Emmanuel Fortunato Gulino ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Methodological Approach ◽  
Polymer Chains ◽  
General Question ◽  
Protective Agent ◽  
Vapour Permeability ◽  
X Ray ◽  
Solid State Nmr Spectroscopy

Hydrophobic treatment is one of the most important interventions usually carried out for the conservation of stone artefacts and monuments. The study here reported aims to answer a general question about how two polymers confer different protective performance. Two fluorinated-based polymer formulates applied on samples of Cusa’s stone confer a different level of water repellence and water vapour permeability. The observed protection action is here explained on the basis of chemico-physical interactions. The distribution of the polymer in the pore network was investigated using scanning electron microscopy and X-ray microscopy. The interactions between the stone substrate and the protective agents were investigated by means of solid state NMR spectroscopy. The ss-NMR findings reveal no significant changes in the chemical neighbourhood of the observed nuclei of each protective agent when applied onto the stone surface and provide information on the changes in the organization and dynamics of the studied systems, as well as on the mobility of polymer chains. This allowed us to explain the different macroscopic behaviours provided by each protective agent to the stone substrate.

Dynamic Motion of Organic Spacer Cations in Ruddlesden–Popper Lead Iodide Perovskites Probed by Solid-State NMR Spectroscopy

2021 ◽  
Vol 33 (2) ◽  
pp. 642-656
Author(s):  
Clayton J. Dahlman ◽  
Rhys M. Kennard ◽  
Piotr Paluch ◽  
Naveen R. Venkatesan ◽  
Michael L. Chabinyc ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Lead Iodide ◽  
Solid State Nmr Spectroscopy ◽  
Dynamic Motion
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