Lanthanum-139 Nuclear Magnetic Resonance Studies of Solid Oxo-Coordinate Compounds
EMSL Project ID
7591
Abstract
Lanthanum-139 nuclear magnetic resonance (NMR) provides an excellent opportunity to study the unique properties of characteristically high-coordinate lanthanide complexes. Of the few La-139 solid-state NMR investigations that have appeared in the literature, the majority have been on relatively simple, paramagnetic inorganic lanthanum complexes. This is rather surprising, given that 139La (I = 7/2) is essentially 100 % natural abundant and, with Ξ = 14.13 MHz, sits at an ideal frequency for study at multiple external applied magnetic fields ? even in the solid state. Considering that 139La NMR is practical and that lanthanum forms complexes with numerous ligands, with a wide variety of coordination numbers, both novel and fundamental information will be obtained from La-139 NMR studies of solid samples. The major hindrance to 139La NMR is its moderately large quadrupole moment (Q = 20.0 fm2). By employing the highest available magnetic fields, the second order quadrupolar interaction can be reduced, while increasing the visible effect of magnetic shielding anisotropy, thereby enabling complete characterization of these interactions. Solid-state 139La NMR will be applied to a series of oxo-coordinate compounds, ranging from four- to twelve-coordinate with the goal of characterizing electric field gradient, and potentially, chemical shift tensors. A detailed investigation of these complexes should yield insightful conclusions correlating the molecular structure and coordination number of oxo-coordinate lanthanum compounds with NMR observables.
Project Details
Project type
Capability Research
Start Date
2004-07-01
End Date
2004-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
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Ooms KJ, KW Feindel, MJ Willans, RE Wasylishen, JV Hanna, KJ Pike, and ME Smith. 2005. "Multiple-magnetic field 139La NMR and density functional theory
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