Observability of Paramagnetic NMR Signals at over 10 000 ppm Chemical Shifts.
Angew Chem Int Ed Engl
; 60(42): 22856-22864, 2021 Oct 11.
Article
en En
| MEDLINE
| ID: mdl-34351041
ABSTRACT
We report an experimental observation of 31 Pâ
NMR resonances shifted by over 10 000â
ppm (meaning percent range, and a new record for solutions), and similar 1 H chemical shifts, in an intermediate-spin square planar ferrous complex [tBu (PNP)Fe-H], where PNP is a carbazole-based pincer ligand. Using a combination of electronic structure theory, nuclear magnetic resonance, magnetometry, and terahertz electron paramagnetic resonance, the influence of magnetic anisotropy and zero-field splitting on the paramagnetic shift and relaxation enhancement is investigated. Detailed spin dynamics simulations indicate that, even with relatively slow electron spin relaxation (T1 ≈10-11 â
s), it remains possible to observe NMR signals of directly metal-bonded atoms because pronounced rhombicity in the electron zero-field splitting reduces nuclear paramagnetic relaxation enhancement.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Angew Chem Int Ed Engl
Año:
2021
Tipo del documento:
Article
País de afiliación:
Alemania