Tensor Interplay

Bryce, David L.

doi:10.1002/9780470034590.emrstm1039

Cited by 7 publications

(10 citation statements)

References 38 publications

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“…The 17 O MAS and static NMR spectra of 17 O-labeled Ph 3 PO were acquired at 9.4 T and are shown in Figure . Simulation of the 17 O NMR spectra provides the following 17 O NMR parameters which are consistent with those of Bryce and which are shown in Table : δ iso , the magnitude of | C Q | and η Q from MAS spectra, as well as the CS tensor span (Ω), skew (κ), and three Euler angles (α, β, γ) from static spectra . Also, the magnitude of J iso ( 31 P, 17 O) obtained from 31 P MAS NMR spectra can be confirmed in the 17 O MAS spectrum through the measurement of the splittings of each spectral discontinuity.…”

Section: Resultssupporting

confidence: 82%

Mechanochemical Production of Halogen-Bonded Solids Featuring P═O···I–C Motifs and Characterization via X-ray Diffraction, Solid-State Multinuclear Magnetic Resonance, and Density Functional Theory

Viger‐Gravel

Korobkov

et al. 2015

J. Phys. Chem. C

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A series of phosphine oxide-iodofluorobenzene cocrystals featuring relatively strongly halogen-bonded PO···I–C motifs has been prepared mechanochemically and characterized by 31P and 17O solid-state nuclear magnetic resonance (SSNMR) spectroscopy and single-crystal X-ray diffraction. Direct insights were obtained into the correlation between several NMR observables (chemical shift tensors, electric field gradient tensors, and J(31P, 17O) coupling) and the molecular and electronic structure of the halogen bonds. The 31P isotropic chemical shift and span, the 17O quadrupolar coupling constant and asymmetry parameter, as well as J(31P, 17O) coupling can be strong indicators of the presence of a halogen bond. Density functional theory calculations using periodic boundary conditions have revealed several notable trends. For example, the oxygen isotropic chemical shift and J(31P, 17O) values were found to correlate linearly with the strength of the halogen bond. An additional natural localized molecular orbital (NLMO) investigation shows that the three main contributions to J(31P, 17O) coupling are the PO bonding orbitals, the oxygen lone pair orbital, and oxygen core orbitals, and that they all together determine the overall trend observed experimentally. Further NLMO analysis revealed a linear correlation between the contribution of the oxygen p z lone pair orbital to the quadrupolar coupling constant and the strength of the halogen bond. This work, encompassing the first 17O SSNMR studies of halogen bonds, demonstrates how NMR observables provide a useful means to characterize halogen bonds and also improve our understanding of the correlation between the electronic structure of the halogen bond and NMR properties.

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Section: Resultssupporting

confidence: 82%

Mechanochemical Production of Halogen-Bonded Solids Featuring P═O···I–C Motifs and Characterization via X-ray Diffraction, Solid-State Multinuclear Magnetic Resonance, and Density Functional Theory

Viger‐Gravel

Korobkov

et al. 2015

J. Phys. Chem. C

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“…We also experimentally observed that β = 90(20)°, which is the first experimental observation of noncoincident iodine δ 33 and V 33 eigenvectors. Information describing the ‘interplay’ between the V̈ and δ̈ tensors has been useful in the determination of crystallographic information, even in cases where conclusive diffraction studies are absent …”

Section: Resultsmentioning

confidence: 99%

“…Three Euler angles (α, β, and γ) describe the relative orientation, and we use the ‘ZYZ’ convention herein to report these values . Additional information pertaining to Euler angles has recently been summarized . As magnetic shielding and QI effects on the SSNMR line shape scale differently with B 0 , 127 I SSNMR spectra have been acquired at multiple fields, when possible, to improve the accuracy of the extracted parameters.…”

Section: Methodsmentioning

confidence: 99%

Solid-State ¹²⁷I NMR and GIPAW DFT Study of Metal Iodides and Their Hydrates: Structure, Symmetry, and Higher-Order Quadrupole-Induced Effects

Widdifield

Bryce

2010

J. Phys. Chem. A

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Central-transition (127)I solid-state nuclear magnetic resonance (SSNMR) spectra are presented for several anhydrous group 2 metal iodides (MgI(2), CaI(2), SrI(2), and BaI(2)), hydrates (BaI(2)·2H(2)O and SrI(2)·6H(2)O), and CdI(2) (4H polytype). Variable offset cumulative spectrum data acquisition coupled with echo pulse sequences and an 'ultrahigh' applied field of 21.1 T were usually suitable to acquire high-quality spectra. Spectral analysis revealed iodine-127 nuclear quadrupole coupling constants (C(Q)((127)I)) ranging in magnitude from 43.5 (CaI(2)) to 214 MHz (one site in SrI(2)). For very large C(Q), analytical second-order perturbation theory could not be used to reliably extract chemical shifts and a treatment which includes quadrupolar effects exactly was required (Bain, A. D. Mol. Phys. 2003, 101, 3163). Differences between second-order and exact modeling allowed us to observe 'higher-order' quadrupole-induced effects for the first time. This finding will have implications for the interpretation of SSNMR spectra of quadrupolar nuclei with large quadrupole moments. In favorable situations (i.e., C(Q)((127)I) < 120 MHz), measurements were also performed at 11.75 T which when combined with the 21.1 T data allowed us to measure iodine chemical shift (CS) tensor spans in the range from 60 (BaI(2)·2H(2)O) to 300 ppm (one site in BaI(2)). These measurements represent the first complete characterizations (i.e., electric field gradient and CS tensors as well as their relative orientation) of noncubic iodide sites using (127)I SSNMR. In select cases, the SSNMR data are supported with (127)I NQR measurements. We also summarize a variety of trends in the halogen SSNMR parameters for group 2 metal halides. Gauge-including projector-augmented wave DFT computations are employed to complement the experimental observations, to predict potential structures for the two hydrates, and to highlight the sensitivity of C(Q)((127)I) to minute structural changes, which has potential applications in NMR crystallography.

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“…Three Euler angles (α, β, and γ) describe the relative orientation. Further information pertaining to Euler angle conventions may be found in ref . As the magnetic shielding and QI each possess a different B 0 dependence, one approach to improve the precision of the measurement is to acquire data at two different applied fields.…”

Section: Solid-state Nmr: Observable Parametersmentioning

confidence: 99%

Solid-State ^79/81Br NMR and Gauge-Including Projector-Augmented Wave Study of Structure, Symmetry, and Hydration State in Alkaline Earth Metal Bromides

Widdifield

Bryce

2010

J. Phys. Chem. A

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Bromine-79/81 solid-state NMR (SSNMR) spectroscopy is established as a tool to characterize the local structure and symmetry about bromide ions in inorganic systems. Benchmark experimental 79/81Br SSNMR data are acquired for CaBr2, SrBr2, BaBr2, MgBr2·6H2O, SrBr2·6H2O, BaBr2·2H2O, and CaBr2·xH2O using the Solomon echo and/or QCPMG pulse sequences in magnetic fields of 11.75 and 21.1 T. Analytical line-shape analysis provides 79/81Br electric field gradient (EFG) tensor parameters (including 79Br quadrupolar coupling constants, C Q(79Br), of up to 75.1(5) MHz in CaBr2), chemical shift tensor parameters (including the largest reported anisotropy), and the relative orientation of the tensor principal axis systems. These data are interpreted in terms of structure and symmetry. Our results indicate that ionic bromide systems should be generally accessible to characterization by 79/81Br SSNMR despite sizable quadrupolar interactions. The resolving capabilities of 79/81Br SSNMR spectroscopy are illustrated, using samples which possess up to four magnetically inequivalent sites, and through a rare example of 79Br magic-angle spinning NMR for a Br in a noncubic lattice. Bromine-79/81 SSNMR spectroscopy is demonstrated to be sensitive to the presence of hydrates (i.e., pseudopolymorphism), via drastic changes in C Q and δiso. The changes are diagnostic to an extent that the composition of the mixture CaBr2·xH2O is determined for the first time. This technique should therefore be applicable to characterize other unknown mixtures or polymorphs. Important instances where 79Br nuclear quadrupole resonance data were found to be deficient are noted and corrected. GIPAW DFT computations are shown to be generally in very good agreement with the experimental 79/81Br SSNMR observations. Finally, it is demonstrated that the origin of the EFG at the Br nuclei cannot be described quantitatively using a point charge model, even after including Sternheimer antishielding effects.

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Tensor Interplay

Cited by 7 publications

References 38 publications

Mechanochemical Production of Halogen-Bonded Solids Featuring P═O···I–C Motifs and Characterization via X-ray Diffraction, Solid-State Multinuclear Magnetic Resonance, and Density Functional Theory

Mechanochemical Production of Halogen-Bonded Solids Featuring P═O···I–C Motifs and Characterization via X-ray Diffraction, Solid-State Multinuclear Magnetic Resonance, and Density Functional Theory

Solid-State ¹²⁷I NMR and GIPAW DFT Study of Metal Iodides and Their Hydrates: Structure, Symmetry, and Higher-Order Quadrupole-Induced Effects

Solid-State ^79/81Br NMR and Gauge-Including Projector-Augmented Wave Study of Structure, Symmetry, and Hydration State in Alkaline Earth Metal Bromides

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Tensor Interplay

Cited by 7 publications

References 38 publications

Mechanochemical Production of Halogen-Bonded Solids Featuring P═O···I–C Motifs and Characterization via X-ray Diffraction, Solid-State Multinuclear Magnetic Resonance, and Density Functional Theory

Mechanochemical Production of Halogen-Bonded Solids Featuring P═O···I–C Motifs and Characterization via X-ray Diffraction, Solid-State Multinuclear Magnetic Resonance, and Density Functional Theory

Solid-State 127I NMR and GIPAW DFT Study of Metal Iodides and Their Hydrates: Structure, Symmetry, and Higher-Order Quadrupole-Induced Effects

Solid-State 79/81Br NMR and Gauge-Including Projector-Augmented Wave Study of Structure, Symmetry, and Hydration State in Alkaline Earth Metal Bromides

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Solid-State ¹²⁷I NMR and GIPAW DFT Study of Metal Iodides and Their Hydrates: Structure, Symmetry, and Higher-Order Quadrupole-Induced Effects

Solid-State ^79/81Br NMR and Gauge-Including Projector-Augmented Wave Study of Structure, Symmetry, and Hydration State in Alkaline Earth Metal Bromides