A Thermometer for Nonspinning Solid-State NMR Spectroscopy

Beckmann, Peter A.; Dybowski, Cecil

doi:10.1006/jmre.2000.2171

Cited by 142 publications

(140 citation statements)

References 6 publications

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“…The significantly long spin-relaxation times of these mercury materials in the solid state were measured by the saturation-recovery technique [29]. Temperature measurements were calibrated with the chemical shift of solid lead nitrate for both static [30] and MAS [31][32][33] experiments.…”

Section: Methodsmentioning

confidence: 99%

A solid-state 199Hg NMR study of mercury halides

Taylor

Bai

Dybowski

2011

Journal of Molecular Structure

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Abstract:The principal elements of the 199 Hg chemical-shift (CS) tensors of the mercuric halides (HgX 2 , X = F, Cl, Br, and I) and the mercurous halides (Hg 2 X 2 , X = F and Cl) were determined from spectra of static polycrystalline powders and from magic-angle spinning (MAS) spectra. The CS tensors of both HgCl 2 and Hg 2 Cl 2 are axially symmetric (η = 0) within experimental error, differing from literature reports of η=0.12 and η=0.14, respectively. The principal elements of the axially symmetric CS tensor in HgBr 2 were also measured using a static sample, and the wideline spectra of HgF 2 and HgI 2 (red polymorph) give chemical-shift tensors that suggest, within experimental error, that the mercury sits in sites of cubic symmetry. The 199 Hg CS tensor for Hg 2 F 2 is asymmetric.Experiments with static polycrystalline samples may allow the determination of the elements of the 199 Hg CS tensors even when MAS fails to completely average the dipolar coupling of the spin-½ 199 Hg and the quadrupolar halide nucleus.

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Section: Methodsmentioning

confidence: 99%

A solid-state 199Hg NMR study of mercury halides

Taylor

Bai

Dybowski

2011

Journal of Molecular Structure

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“…The significantly longer spin-relaxation times in the solid state were measured by the saturation-recovery technique [21]. Temperature measurements for solution NMR were calibrated with ethylene glycol [22] while the chemical shift of lead nitrate was used to calibrate the solid-state measurements for static [23] and MAS [24][25][26] experiments.…”

Section: Experimental and Theoretical Methodsmentioning

confidence: 99%

Revisiting HgCl2: A solution- and solid-state 199Hg NMR and ZORA–DFT computational study

Taylor

Carver

Larsen

et al. 2009

Journal of Molecular Structure

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The 199 Hg chemical-shift tensor of solid HgCl 2 was determined from spectra of polycrystalline materials, using static and magic-angle spinning (MAS) techniques at multiple spinning frequencies and field strengths. The chemical-shift tensor of solid HgCl 2 is axially symmetric (η = 0) within experimental error. The 199 Hg chemical-shift anisotropy (CSA) of HgCl 2 in a frozen solution in dimethylsulfoxide (DMSO) is significantly smaller than that of the solid, implying that the local electronic structure in the solid is different from that of the material in solution. The experimental chemicalshift results (solution and solid-state) are compared with those predicted by density functional theory (DFT) calculations using the zeroth-order regular approximation (ZORA) to account for relativistic effects.199 Hg spin-lattice relaxation of HgCl 2 dissolved in DMSO is dominated by a CSA mechanism, but a second contribution to relaxation arises from ligand exchange. Relaxation in the solid state is independent of temperature, suggesting relaxation by paramagnetic impurities or defects.

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“…To check for these effects, the -325 mesh AlB 2 sample was also mixed with an equal volume of PbNO 3 . Monitoring of the 207 Pb chemical shift [19][20][21] at a MAS spinning rate of 5 kHz indicated only a modest 3.6 K increase in sample temperature over that of the static sample. This is the small temperature increase expected from frictional heating of the sample under MAS at this spinning rate.…”

Section: B Inmentioning

confidence: 97%

Synthesis and characterization of aluminum diboride products using 27Al, 11B NMR and ab initio studies

Turner

Koumoulis

et al. 2017

J Mater Sci

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Understanding different bonding environments in various metal borides provides insight into their structures and physical properties. Polycrystalline aluminum diboride (AlB 2 ) samples have been synthesized and compared both with a commercial sample and with the literature. One issue that arose is the relative ease with which boron-rich and aluminum deficient phases of aluminum borides can be presented in AlB 2 . Here, we report 27 Al, 11 B nuclear magnetic resonance (NMR) spectroscopy and first-principles calculations on AlB 2 in order to shed light on these different bonding environments at the atomic level and compare the structural and electronic properties of the products of different preparations. Along with the aforementioned, the present study also takes an indepth look at the nature of the 11 B and 27 Al nuclear spin-lattice relaxation recovery data for the AlB 2 and other superhard materials. The nuclear spinlattice relaxation has been measured for a static sample and with magic-angle spinning. The combination of NMR and band structure calculations highlights the synthetic challenges with superhard materials.

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A Thermometer for Nonspinning Solid-State NMR Spectroscopy

Cited by 142 publications

References 6 publications

A solid-state 199Hg NMR study of mercury halides

A solid-state 199Hg NMR study of mercury halides

Revisiting HgCl2: A solution- and solid-state 199Hg NMR and ZORA–DFT computational study

Synthesis and characterization of aluminum diboride products using 27Al, 11B NMR and ab initio studies

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