Simulation of NMR powder line shapes of quadrupolar nuclei with half-integer spin at low-symmetry sites

Power, William P.; Wasylishen, Roderick E.; Mooibroek, Sandra; Pettitt, Brian A.; Danchura, Werner

doi:10.1021/j100365a019

Cited by 116 publications

(119 citation statements)

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“…d 33 , and the relative orientation of EFG and chemical-shift tensors may also influence the 139 La NMR lineshape. [45,46] The EFG tensor is described by the nuclear quadrupolar coupling constant, C Q = eQV ZZ h À1 , where e is the elementary charge, Q is the nuclear quadrupole moment, and h is the Planck constant, and the asymmetry parameter, ), which is restricted to values between À1 and + 1. [47] The relative orientation of the EFG and chemical-shift tensors is defined by the Euler angles-a, b, and g-and thus a total of eight parameters describe the NMR spectra, theoretical examples of which are presented in Figure 1 Typical experimental 139 La NMR spectra of solid lanthanum(iii) coordination compounds at applied magnetic fields of 11.75 and 17.60 T can be found in Figures 2-5.…”

Section: Resultsmentioning

confidence: 99%

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

Willans

Feindel

Ooms

et al. 2005

Chemistry A European J

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Lanthanum-139 NMR spectra of stationary samples of several solid La(III) 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 (C(Q)) range from 10.0 to 35.6 MHz, the spans of the chemical-shift tensor (Omega) range from 50 to 260 ppm, and the isotropic chemical shifts (delta(iso)) range from -80 to 178 ppm. In general, there is a correlation between the magnitudes of C(Q) and Omega, and delta(iso) 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.

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Section: Resultsmentioning

confidence: 99%

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

Willans

Feindel

Ooms

et al. 2005

Chemistry A European J

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“…Spectral lineshape simulations [60] were performed with WSOLIDS1 version 1.17.30. [61] A lineshape fitting strategy was employed in which the CT center band lineshape of a fast MAS sample is first analyzed.…”

Section: Experimental and Computational Detailsmentioning

confidence: 99%

Alkaline Earth Chloride Hydrates: Chlorine Quadrupolar and Chemical Shift Tensors by Solid‐State NMR Spectroscopy and Plane Wave Pseudopotential Calculations

Bryce

Bultz

2007

Chemistry A European J

114

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A series of alkaline earth chloride hydrates has been studied by solid-state (35/37)Cl NMR spectroscopy in order to characterize the chlorine electric field gradient (EFG) and chemical shift (CS) tensors and to relate these observables to the structure around the chloride ions. Chlorine-35/37 NMR spectra of solid powdered samples of pseudopolymorphs (hydrates) of magnesium chloride (MgCl(2).6H(2)O), calcium chloride (CaCl(2).2H(2)O), strontium chloride (SrCl(2), SrCl(2).2H(2)O, and SrCl(2).6H(2)O), and barium chloride (BaCl(2).2H(2)O) have been acquired under stationary and magic-angle spinning conditions in magnetic fields of 11.75 and 21.1 T. Powder X-ray diffraction was used as an additional tool to confirm the purity and identity of the samples. Chlorine-35 quadrupolar coupling constants (C(Q)) range from essentially zero in cubic anhydrous SrCl(2) to 4.26+/-0.03 MHz in calcium chloride dihydrate. CS tensor spans, Omega, are between 40 and 72 ppm, for example, Omega= 45+/-20 ppm for SrCl(2).6H(2)O. Plane wave-pseudopotential density functional theory, as implemented in the CASTEP program, was employed to model the extended solid lattices of these materials for the calculation of their chlorine EFG and nuclear magnetic shielding tensors, and allowed for the assignment of the two-site chlorine NMR spectra of barium chloride dihydrate. This work builds upon our current understanding of the relationship between chlorine NMR interaction tensors and the local molecular and electronic structure, and highlights the particular sensitivity of quadrupolar nucleus solid-state NMR spectroscopy to the differences between various pseudopolymorphic structures in the case of strontium chloride.

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“…[22][23][24] We present here only the conventions used in the current work. The two most important interactions to consider presently are the nuclear magnetic shielding interaction and the quadrupolar interaction.…”

Section: Background Theorymentioning

confidence: 99%

Chlorine-35/37 NMR Spectroscopy of Solid Amino Acid Hydrochlorides: Refinement of Hydrogen-Bonded Proton Positions Using Experiment and Theory

2006

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Trends in the chlorine chemical shift (CS) tensors of amino acid hydrochlorides are investigated in the context of new data obtained at 21.1 T and extensive quantum chemical calculations. The analysis of chlorine-35/37 NMR spectra of solid L-tryptophan hydrochloride obtained at two magnetic field strengths yields the chlorine electric field gradient (EFG) and CS tensors, and their relative orientations. The chlorine CS tensor is also determined for the first time for DL-arginine hydrochloride monohydrate. The drastic influence of 1 H decoupling at 21.1 T on the spectral features of salts with particularly small 35 Cl quadrupolar coupling constants (C Q ) is demonstrated. The chlorine CS tensor spans (Ω) of hydrochloride salts of hydrophobic amino acids are found to be larger than those for salts of hydrophilic amino acids. A new combined experimental-theoretical procedure is described in which quantum chemical geometry optimizations of hydrogen-bonded proton positions around the chloride ions in a series of amino acid hydrochlorides are cross-validated against the experimental chlorine EFG and CS tensor data. The conclusion is reached that the relatively computationally inexpensive B3LYP/ 3-21G* method provides proton positions which are suitable for subsequent higher-level calculations of the chlorine EFG tensors. The computed value of Ω is less sensitive to the proton positions. Following this cross-validation procedure, |C Q ( 35 Cl)| is generally predicted within 15% of the experimental value for a range of HCl salts. The results suggest the applicability of chlorine NMR interaction tensors in the refinement of proton positions in structurally similar compounds, e.g., chloride ion channels, for which neutron diffraction data are unavailable. IntroductionThe availability of high-field solid-state nuclear magnetic resonance (NMR) spectrometers, e.g., those with 1 H resonance frequencies of 800 MHz, 900 MHz, and above, has created new opportunities for the study of quadrupolar nuclei (I > 1/ 2) with low resonance frequencies or large quadrupole moments, and for nuclei with both of these properties. For example, Stebbins et al. have described applications of 18.8 and 21.1 T solid-state 27 Al, 17 O, 39 K, and 35 Cl NMR spectroscopy to study oxide materials. 1-3 Gan et al. used magnetic fields as high as 40 T to achieve chemical shift resolution between four different aluminum environments in aluminoborate. 4 Ellis and colleagues have applied high-field 67 Zn NMR at low temperature to study zinc binding environments of biological relevance. 5,6,7,8 Magicangle-spinning (MAS) NMR in a magnetic field of 19.6 T has been applied by Wu and co-workers to detect potassium cations in guanine-quadruplex structures 9 as well as to explore cation-π interactions in alkali metal tetraphenylborates. 10 Cross and coworkers have demonstrated the utility of 17 O solid-state NMR at 21.1 T for characterizing the ion channel gramicidin. 11,12 The major reason that higher fields are so beneficial for the study of quadrupolar nuclei in ...

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Simulation of NMR powder line shapes of quadrupolar nuclei with half-integer spin at low-symmetry sites

Cited by 116 publications

References 4 publications

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

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

Alkaline Earth Chloride Hydrates: Chlorine Quadrupolar and Chemical Shift Tensors by Solid‐State NMR Spectroscopy and Plane Wave Pseudopotential Calculations

Chlorine-35/37 NMR Spectroscopy of Solid Amino Acid Hydrochlorides: Refinement of Hydrogen-Bonded Proton Positions Using Experiment and Theory

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Simulation of NMR powder line shapes of quadrupolar nuclei with half-integer spin at low-symmetry sites

Cited by 116 publications

References 4 publications

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

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

Alkaline Earth Chloride Hydrates: Chlorine Quadrupolar and Chemical Shift Tensors by Solid‐State NMR Spectroscopy and Plane Wave Pseudopotential Calculations

Chlorine-35/37 NMR Spectroscopy of Solid Amino Acid Hydrochlorides: Refinement of Hydrogen-Bonded Proton Positions Using Experiment and Theory

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

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