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Title: An Investigation of Lanthanum Coordination Compounds by Using Solid- State 139La NMR Spectroscopy and Relativistic Density Functional Theory

Abstract

Lanthanum-139 NMR spectra of stationary samples of several solid LaIII coordination compounds have been obtained at applied magnetic fields of 11.75 and 17.60 T. The breadth and shape of the 139La NMR spectra of the central transition are dominated by the interaction between the 139La nuclear quadrupole moment and the electric field gradient (EFG) at that nucleus; however, the influence of chemical-shift anisotropy on the NMR spectra is non-negligible for the majority of the compounds investigated. Analysis of the experimental NMR spectra reveals that the 139La quadrupolar coupling constants (CQ) range from 10.0 to 35.6 MHz, the spans of the chemical-shift tensor (W) range from 50 to 260 ppm, and the isotropic chemical shifts (diso) range from -80 to 178 ppm. In general, there is a correlation between the magnitudes of CQ and W, and diso is shown to depend on the La coordination number. Magnetic shielding tensors, calculated by using relativistic zeroth-order regular approximation density functional theory (ZORA-DFT) and incorporating scalar only or scalar plus spin-orbit relativistic effects, qualitatively reproduce the experimental chemical-shift tensors. In general, the inclusion of spin-orbit coupling yields results that are in better agreement with those from the experiment. The magnetic-shielding calculations and experimentally determinedmore » Euler angles can be used to predict the orientation of the chemical-shift and EFG tensors in the molecular frame. This study demonstrates that solid state 139La NMR spectroscopy is a useful characterization method and can provide insight into the molecular structure of lanthanum coordination compounds.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
889082
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Chemistry - a European Journal; Journal Volume: 12; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; LANTHANUM COMPOUNDS; NUCLEAR MAGNETIC RESONANCE; DENSITY FUNCTIONAL METHOD; LANTHANUM 139; NMR SPECTRA; CHEMICAL SHIFT; Environmental Molecular Sciences Laboratory

Citation Formats

Willans, Mathew J., Feindel, Kirk W., Ooms, Kristopher J., and Wasylishen, Roderick E. An Investigation of Lanthanum Coordination Compounds by Using Solid- State 139La NMR Spectroscopy and Relativistic Density Functional Theory. United States: N. p., 2005. Web.
Willans, Mathew J., Feindel, Kirk W., Ooms, Kristopher J., & Wasylishen, Roderick E. An Investigation of Lanthanum Coordination Compounds by Using Solid- State 139La NMR Spectroscopy and Relativistic Density Functional Theory. United States.
Willans, Mathew J., Feindel, Kirk W., Ooms, Kristopher J., and Wasylishen, Roderick E. Fri . "An Investigation of Lanthanum Coordination Compounds by Using Solid- State 139La NMR Spectroscopy and Relativistic Density Functional Theory". United States. doi:.
@article{osti_889082,
title = {An Investigation of Lanthanum Coordination Compounds by Using Solid- State 139La NMR Spectroscopy and Relativistic Density Functional Theory},
author = {Willans, Mathew J. and Feindel, Kirk W. and Ooms, Kristopher J. and Wasylishen, Roderick E.},
abstractNote = {Lanthanum-139 NMR spectra of stationary samples of several solid LaIII coordination compounds have been obtained at applied magnetic fields of 11.75 and 17.60 T. The breadth and shape of the 139La NMR spectra of the central transition are dominated by the interaction between the 139La nuclear quadrupole moment and the electric field gradient (EFG) at that nucleus; however, the influence of chemical-shift anisotropy on the NMR spectra is non-negligible for the majority of the compounds investigated. Analysis of the experimental NMR spectra reveals that the 139La quadrupolar coupling constants (CQ) range from 10.0 to 35.6 MHz, the spans of the chemical-shift tensor (W) range from 50 to 260 ppm, and the isotropic chemical shifts (diso) range from -80 to 178 ppm. In general, there is a correlation between the magnitudes of CQ and W, and diso is shown to depend on the La coordination number. Magnetic shielding tensors, calculated by using relativistic zeroth-order regular approximation density functional theory (ZORA-DFT) and incorporating scalar only or scalar plus spin-orbit relativistic effects, qualitatively reproduce the experimental chemical-shift tensors. In general, the inclusion of spin-orbit coupling yields results that are in better agreement with those from the experiment. The magnetic-shielding calculations and experimentally determined Euler angles can be used to predict the orientation of the chemical-shift and EFG tensors in the molecular frame. This study demonstrates that solid state 139La NMR spectroscopy is a useful characterization method and can provide insight into the molecular structure of lanthanum coordination compounds.},
doi = {},
journal = {Chemistry - a European Journal},
number = 1,
volume = 12,
place = {United States},
year = {Fri Dec 16 00:00:00 EST 2005},
month = {Fri Dec 16 00:00:00 EST 2005}
}
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