WSOLIDS1: MAS: Chemical shift anisotropy (HB) [ Go Home ]

This squeezed picture shows an example for the succesful simulation of a spectrum arising from chemical shift anisotropy in a powder sample under magic-angle spinning. It is the ³¹P CP/MAS NMR spectrum of a phosphinidene ruthenium cluster, nido-Ru₄(CO)₁₃(m³-PPh), and the results have been published in:

K. Eichele, R. E. Wasylishen, J. F. Corrigan, N. J. Taylor, A. J. Carty:
Phosphorus-31 Chemical Shift Tensors of Phosphinidene Ligands in Ruthenium Carbonyl Cluster Compounds: A ³¹P Single-Crystal and CP/MAS NMR Study.
J. Am. Chem. Soc. 1995, 117, 6961-6969.

Click on the picture to have a better look.

Background

In addition to the chemical shift anisotropy (CSA), the spectrum of a spin in a powder sample under-magic angle spinning will depend on the spinning frequency, if the spinning frequency is lower than the width of the chemical shift powder pattern. In this case, the isotropic peak (center peak) is flanked by spinning sidebands spaced at integer multiples of the spinning rate. The intensities of the spinning sidebands are intimately related to the principal components of the chemical shift tensor. For efficiency reasons, WSolids uses look-up tables of precomputed spinning sideband intensities.

[ Go Home ] | last modified: 16.08.2001