Multiple-magnetic field 139La NMR and density functional theory investigation of the solid lanthanum(III) halides

Kristopher J Ooms; Kirk W Feindel; Mathew J Willans; Roderick E Wasylishen; John V Hanna; Kevin J Pike; Mark E Smith

doi:10.1016/j.ssnmr.2005.07.002

Multiple-magnetic field 139La NMR and density functional theory investigation of the solid lanthanum(III) halides

Solid State Nucl Magn Reson. 2005 Sep;28(2-4):125-34. doi: 10.1016/j.ssnmr.2005.07.002. Epub 2005 Aug 24.

Authors

Kristopher J Ooms¹, Kirk W Feindel, Mathew J Willans, Roderick E Wasylishen, John V Hanna, Kevin J Pike, Mark E Smith

Affiliation

¹ Department of Chemistry, Gunning/Lemieux Chemistry Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2G2.

PMID: 16125375
DOI: 10.1016/j.ssnmr.2005.07.002

Abstract

Results from a solid-state 139La NMR spectroscopic investigation of the anhydrous lanthanum(III) halides (LaX3; X=F, Cl, Br, I) at applied magnetic fields of 7.0, 9.4, 11.7, 14.1, and 17.6 T are presented and highlight the advantages of working at high applied magnetic field strengths. The 139La quadrupolar coupling constants are found to range from 15.55 to 24.0 MHz for LaCl3 and LaI3, respectively. The lanthanum isotropic chemical shifts exhibit an inverse halogen dependence with values ranging from -135 ppm for LaF3 to 700 ppm for LaI3, which represents nearly half of the total lanthanum chemical shift range. The spans of the magnetic shielding tensors also vary widely, from 35 to 650 ppm for the solid LaF3 through LaI3. DFT calculations of the 139La electric field gradient and magnetic shielding tensors have been performed and provide a qualitative interpretation of the trends observed experimentally.