CeTiO2N oxynitride perovskite: paramagnetic 14N MAS NMR without paramagnetic shifts

14N magic-angle spinning (MAS) NMR spectra of diamagnetic LaTiO2N perovskite oxynitride and its paramag- netic counterpart CeTiO2N are presented. The latter, to the best of our knowledge, constitutes the first high-resolution 14N MAS NMR spectrum collected from paramagnetic solid material. Induced paramagnetic 14N NMR shift due to unpaired 4f -electrons in CeTiO2N is non-existent, which is remarkable given the severe paramagnetic effects on surface proton species revealed by 1H NMR, and direct Ce−N contacts in the structure. Ab initio molecular orbital calculations predict substantial Ce→14N contact shift interaction under these circumstances, therefore, cannot explain the unprecedented 14N NMR spectrum of CeTiO2N.

Download Full-text

Paramagnetic 14N MAS NMR without Paramagnetic Shifts: Remarkable Lattice of LaTiO2N and CeTiO2N Oxynitride Perovskites

10.26434/chemrxiv.12902594 ◽

2020 ◽

Author(s):

Zili Ma ◽

Richard Dronskowski ◽

Adam Slabon ◽

Aleksander Jaworski

Keyword(s):

Solid Material ◽

Magic Angle Spinning ◽

Mas Nmr ◽

Magic Angle ◽

Molecular Orbital Calculations ◽

Nmr Spectrum ◽

H Nmr ◽

Contact Shift ◽

Angle Spinning ◽

Paramagnetic Shifts

14N magic-angle spinning (MAS) NMR spectra of diamagnetic LaTiO2N perovskite oxynitride and its paramag- netic counterpart CeTiO2N are presented. The latter, to the best of our knowledge, constitutes the first high-resolution 14N MAS NMR spectrum collected from paramagnetic solid material. Induced paramagnetic 14N NMR shift due to unpaired 4f -electrons in CeTiO2N is non-existent, which is remarkable given the severe paramagnetic effects on surface proton species revealed by 1H NMR, and direct Ce−N contacts in the structure. Ab initio molecular orbital calculations predict substantial Ce→14N contact shift interaction under these circumstances, therefore, cannot explain the unprecedented 14N NMR spectrum of CeTiO2N.

Download Full-text

Basic Principles and Recent Results of H Magic-Angle-Spinning and Pulsed Field Gradient Nuclear Magnetic Resonance Studies on Zeolites11'H Mas Nmr Studies on Dehydrated Zeolites

Studies in Surface Science and Catalysis - Proceedings of ZEOCAT 90 ◽

10.1016/s0167-2991(08)62901-8 ◽

1991 ◽

pp. 89-115 ◽

Cited By ~ 23

Author(s):

H. Pfeifer ◽

D. Freude ◽

J. Kärger

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Magic Angle Spinning ◽

Mas Nmr ◽

Magic Angle ◽

Nmr Studies ◽

Basic Principles ◽

Magnetic Resonance Studies ◽

Pulsed Field ◽

Angle Spinning

Download Full-text

Cross Polarization/Magic Angle Spinning Nuclear Magnetic Resonance (CP/MAS NMR) Spectroscopy

Methods in Lignin Chemistry - Springer Series in Wood Science ◽

10.1007/978-3-642-74065-7_11 ◽

1992 ◽

pp. 146-161 ◽

Cited By ~ 18

Author(s):

G. J. Leary ◽

R. H. Newman

Keyword(s):

Nuclear Magnetic Resonance ◽

Nmr Spectroscopy ◽

Magnetic Resonance ◽

Magic Angle Spinning ◽

Mas Nmr ◽

Magic Angle ◽

Cross Polarization ◽

Angle Spinning ◽

Cp Mas Nmr ◽

Nuclear Magnetic

Download Full-text

Article

Canadian Journal of Chemistry ◽

10.1139/v99-181 ◽

1999 ◽

Vol 77 (11) ◽

pp. 1962-1972

Author(s):

Scott Kroeker ◽

Roderick E Wasylishen

Keyword(s):

Nmr Spectra ◽

Magic Angle Spinning ◽

Mas Nmr ◽

Spin Coupling ◽

Group Symmetry ◽

Magic Angle ◽

Chemical Shielding ◽

Shielding Tensor ◽

Angle Spinning ◽

Spin Spin Coupling

Direct NMR observation of copper-63/65 nuclei in solid K3Cu(CN)4 provides the first experimental example of anisotropic copper chemical shielding. Axially symmetric by virtue of the space group symmetry, the shielding tensor spans 42 ppm, with the greatest shielding when the unique axis is perpendicular to the applied magnetic field. The nuclear quadrupole coupling constant is also appreciable, CQ(63Cu) = -1.125 MHz, reflecting a deviation of the Cu(CN)43- anion from pure tetrahedral symmetry. Spin-spin coupling to 13C nuclei in an isotopically enriched sample is quantified by line-shape simulations of both 13C and 63/65Cu magic-angle spinning (MAS) NMR spectra to be 300 Hz. It is shown that this information is also directly available by 63/65Cu triple-quantum (3Q) MAS NMR. The relative merits of these three approaches to characterizing spin-spin couplings involving half-integer quadrupolar nuclei are discussed. Chemical shielding tensors for nitrogen-15 and carbon-13 are obtained from NMR spectra of non-spinning samples, and are compared to those of tetrahedral group 12 tetracyanometallates. Finally, 2J(63/65Cu,15N) detected in 15N MAS experiments are found to be 19 and 20 Hz for the two crystallographically distinct cyanide ligands.Key words: NMR, quadrupolar nucleus, chemical shielding tensor, multiple-quantum magic-angle spinning, metal cyanide, spin-spin coupling.

Download Full-text