scholarly journals Spying on the boron–boron triple bond using spin–spin coupling measured from 11B solid-state NMR spectroscopy

2015 ◽  
Vol 6 (6) ◽  
pp. 3378-3382 ◽  
Author(s):  
Frédéric A. Perras ◽  
William C. Ewing ◽  
Theresa Dellermann ◽  
Julian Böhnke ◽  
Stefan Ullrich ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Triple Bond ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Solid State Nmr Spectroscopy ◽  
Spin Spin Coupling ◽  
Insight Into

Boron–boron J coupling constants provide new insight into the nature of the boron–boron triple bond.

scholarly journals Probing interactions through space using spin–spin coupling

2014 ◽  
Vol 43 (17) ◽  
pp. 6548-6560 ◽  
Author(s):  
Martin W. Stanford ◽  
Fergus R. Knight ◽  
Kasun S. Athukorala Arachchige ◽  
Paula Sanz Camacho ◽  
Sharon E. Ashbrook ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Spin Coupling ◽  
X Ray ◽  
Solid State Nmr Spectroscopy ◽  
X Ray Crystallography ◽  
B3lyp Calculations ◽  
Spin Spin Coupling

A series of eight 5-(TeAr)-6-(SePh)acenaphthenes (Ar = aryl) were prepared and structurally characterised by X-ray crystallography, solution and solid-state NMR spectroscopy and DFT/B3LYP calculations.

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.

scholarly journals The acidic nature of “NMR-invisible” tri-coordinated framework aluminum species in zeolites

2019 ◽  
Vol 10 (43) ◽  
pp. 10159-10169 ◽  
Author(s):  
Shaohui Xin ◽  
Qiang Wang ◽  
Jun Xu ◽  
Yueying Chu ◽  
Pengfei Wang ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Zeolite Catalysts ◽  
Probe Molecules ◽  
Solid State Nmr Spectroscopy ◽  
Acidic Nature ◽  
Insight Into

A unique insight into the acidic nature of the tri-coordinated framework aluminum (AlFR) in H-ZSM-5 zeolite catalysts has been provided using multi-nuclear and multi-dimensional solid-state NMR spectroscopy in conjunction with TMPO probe molecules.

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