75As, 63Cu NMR and NQR characterization of selected arsenic minerals

Lehmann-Horn, J. A.; Miljak, D.G.; Bastow, Timothy J.

doi:10.1016/j.ssnmr.2013.05.001

Cited by 9 publications

(13 citation statements)

References 20 publications

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“…However, because only one transition is observed in NQR measurements of S = 3/2 nuclei of powder samples, η Q or ν Q cannot be determined independently. 27,29 Furthermore, information about the copper magnetic shielding tensor is not obtained, nor, in the case of powder samples, does the technique yield information about the EFG tensor orientation. Despite its lower receptivity (by almost a factor of 2), copper-65 is often the nucleus of choice for solid-state copper NMR experiments because the contribution of the 65 Cu quadrupolar interaction to the breadth of the central transition powder pattern is only 80% that of 63 Cu, 30 a consequence of the smaller quadrupole moment and the higher magnetogyric ratio for the former.…”

Section: ■ Introductionmentioning

confidence: 99%

Solid-State ⁶³Cu, ⁶⁵Cu, and ³¹P NMR Spectroscopy of Photoluminescent Copper(I) Triazole Phosphine Complexes

Tan

Bernard

et al. 2015

J. Phys. Chem. A

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The results of a solid-state (63/65)Cu and (31)P NMR investigation of several copper(I) complexes with functionalized 3-(2'-pyridyl)-1,2,4-triazole and phosphine ligands that have shown potential in the preparation of photoluminescent devices are reported. For each complex studied, distinct NMR parameters, with moderate (63)Cu nuclear quadrupolar coupling constant (CQ) values ranging from -17.2 to -23.7 MHz, are attributed to subtle variations in the distorted four-coordinate environments about the copper nuclei. The spans of the copper chemical shift (CS) tensors, δ11-δ33, for the mono- and bisphosphine complexes are also similar, ranging from 1000 to 1150 ppm, but that for a complex with a strained bidentate phosphine ligand is only 650 ppm. The effects of residual dipolar and indirect spin-spin coupling arising from the (63/65)Cu- (31)P spin pairs, observed in the solid-state (31)P NMR spectra of these complexes, yield information about the orientations of the copper electric field gradient (EFG) tensors relative to the Cu-P bond. Variable-temperature (31)P NMR measurements for [Cu(bptzH)(dppe)]ClO4 (bptzH = 5-tert-butyl-3-(2'-pyridyl)-1,2,4-triazole; dppe = 1,2-bis(diphenylphosphino)ethane), undertaken to investigate the cause of the broad unresolved spectra observed at room temperature, demonstrate that the broadening arises from partial self-decoupling of the (63/65)Cu nuclei, a consequence of rapid quadrupolar relaxation. Ab initio calculations of copper EFG and CS tensors were performed to probe relationships between NMR parameters and molecular structure. The analysis demonstrated that CQ((63/65)Cu) is negative for all complexes studied here and that the largest components of the EFG tensors are generally coincident with δ11.

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Section: ■ Introductionmentioning

confidence: 99%

Solid-State ⁶³Cu, ⁶⁵Cu, and ³¹P NMR Spectroscopy of Photoluminescent Copper(I) Triazole Phosphine Complexes

Tan

Bernard

et al. 2015

J. Phys. Chem. A

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“…In spin-1/2 AFNMR powders (solid line) the signal is damped with increasing RF amplitude and stretched toward higher pulse strength according to the Bessel function described in Eq. (12). The numerical powder averaging simulations in Eq.…”

Section: Population Transfer Simulations Zeeman and Full Quadrupomentioning

confidence: 99%

AFNMR/NQR signal enhancement via population transfer

Lehmann-Horn

Miljak

2014

Concepts Magnetic Resonance

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Antiferromagnetic nuclear magnetic resonance (AFNMR) and nuclear quadrupole resonance (NQR) are useful techniques to characterize materials in bulk volumes without applying external static magnetic fields. For industrial materials characterization applications, it is crucial to maximize signal‐to‐noise ratio in the available time. We simulate the AFNMR and NQR signal enhancement via population transfer in single crystals and powders and predict the enhancement factors for half‐integer quadrupolar nuclei spin systems. Differences to conventional high‐field NMR population transfer experiments are emphasized. We restrict our discussion to electric field gradients with axial symmetry η = 0. Triple resonance tuned crossed coil experiments on CuFeS2 and In2O3 powders support the numerical results. © 2015 Wiley Periodicals, Inc. Concepts Magn Reson Part A 43A: 147–156, 2015.

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“…These compounds naturally occur in certain types of gold and base-metal deposits [6]. Recently, we have determined the 75 As NQR frequencies of selected arsenic minerals by systematic stepped frequency scanning over a large frequency range [7]. The results were well modelled by first principles ab initio calculations based on density functional theory (DFT) [8], and we demonstrated later that NQR can be a useful tool to detect the presence of contaminant phases such as arsenic or antimony in mining processes [9].…”

Section: Introductionmentioning

confidence: 99%

“…FeAs 2 specimen was obtained from the Huanggang Mine, Inner Mongolia, China[7]. Weak magnetic field measurements at RT were made in a Helmholtz coils pair with a home-built spectrometer developed at CSIRO, Lucas Heights.…”

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confidence: 99%

75 As NQR studies on FeAs 2

Lehmann-Horn

Yong

Miljak

et al. 2015

Solid State Nuclear Magnetic Resonance

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75As, 63Cu NMR and NQR characterization of selected arsenic minerals

Cited by 9 publications

References 20 publications

Solid-State ⁶³Cu, ⁶⁵Cu, and ³¹P NMR Spectroscopy of Photoluminescent Copper(I) Triazole Phosphine Complexes

Solid-State ⁶³Cu, ⁶⁵Cu, and ³¹P NMR Spectroscopy of Photoluminescent Copper(I) Triazole Phosphine Complexes

AFNMR/NQR signal enhancement via population transfer

75 As NQR studies on FeAs 2

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75As, 63Cu NMR and NQR characterization of selected arsenic minerals

Cited by 9 publications

References 20 publications

Solid-State 63Cu, 65Cu, and 31P NMR Spectroscopy of Photoluminescent Copper(I) Triazole Phosphine Complexes

Solid-State 63Cu, 65Cu, and 31P NMR Spectroscopy of Photoluminescent Copper(I) Triazole Phosphine Complexes

AFNMR/NQR signal enhancement via population transfer

75 As NQR studies on FeAs 2

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Solid-State ⁶³Cu, ⁶⁵Cu, and ³¹P NMR Spectroscopy of Photoluminescent Copper(I) Triazole Phosphine Complexes

Solid-State ⁶³Cu, ⁶⁵Cu, and ³¹P NMR Spectroscopy of Photoluminescent Copper(I) Triazole Phosphine Complexes