Nuclear magnetic relaxation studies of <scp>BH<sub>4</sub></scp> in metal Borohydrides

Kim, Chul; Ku, Jessie C.; Hwang, Son‐Jong; Bowman, R. C.; Reiter, Joseph W.

doi:10.1002/bkcs.12401

Cited by 4 publications

(4 citation statements)

References 43 publications

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“…The spin-lattice relaxation data of solid Ca(BH 4 ) 2 were re-simulated with the modified equation. While the new results are very similar to the previous ones, 13 the experimental data was better fitted, as shown in Figure 3. The activation energies for the rotational motion of BH 4 group were given as 24.5 AE 0.8 and 24.3 AE 0.9 kJ/mol from 11 B and 1 H relaxation data, respectively.…”

Section: Modification Of Spin-lattice Relaxation Equation For Metal B...supporting

confidence: 83%

“…Detailed descriptions of

ν_{k}

C_{nk, i}

C_{nk, j}

W^{italicDi}

, and

W^{italicQj}

were given in the previous paper 13 . The transition rates of

W^{italicDi}

and

W^{italicQj}

are the respective functions of the dipolar correlation time

τ_{c}^{italicDD}

and quadrupolar correlation time

τ_{c}^{Q}

.…”

Section: Theoretical Aspectmentioning

confidence: 99%

“…Detailed descriptions of ν k , C nk,i , C nk,j , W Di , and W Qj were given in the previous paper. 13 The transition rates of W Di and W Qj are the respective functions of the dipolar correlation time τ DD c and quadrupolar correlation time τ Q c . Strictly speaking, the two correlation times are not the same, but they are even if the structure of the BH 4 group is assumed to be a rigid body.…”

Section: Theoretical Aspectmentioning

confidence: 99%

“…While some researchers have considered the quadrupolar relaxation effect, those studies were in the simplified form 11,12 . Recently, Kim et al reported a more precise equation of the spin–lattice relaxation of 11 B, including the dipole–dipole interaction and quadrupolar interaction, and the results of the application to the LiBH 4 and Ca(BH 4 ) 2 13 . In this paper, I modified the equation of relaxation derived in the previous paper by considering the quadrupolar interaction and intermolecular interaction more substantially and applied the modified equation to the spin–lattice relaxation of 11 B and 1 H of BH 4 group in solid Mg(BH 4 ) 2 to more precisely determine the thermodynamical parameters.…”

Section: Introductionmentioning

confidence: 99%

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An NMR relaxation study of magnesium borohydride in solid

Kim

2022

Bulletin Korean Chem Soc

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The spin-lattice relaxation phenomenon is a good tool for obtaining the thermodynamical parameters of solid metal borohydrides. In the process of deriving the motional parameters from the NMR experimental data, it is very important to adequately interpret the spin-lattice relaxation data. By more precisely considering the quadrupolar interaction of 11 B and intermolecular 1 H-1 H dipole-dipole interactions, the activation energies and correlation times of the rotational motions of BH 4 group in solid magnesium borohydride could be more accurately determined, and the spin-lattice relaxation phenomenon of the quadrupolar nucleus could be more appropriately understood.

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Section: Modification Of Spin-lattice Relaxation Equation For Metal B...supporting

confidence: 83%

“…Detailed descriptions of

ν_{k}

C_{nk, i}

C_{nk, j}

W^{italicDi}

, and

W^{italicQj}

were given in the previous paper 13 . The transition rates of

W^{italicDi}

and

W^{italicQj}

are the respective functions of the dipolar correlation time

τ_{c}^{italicDD}

and quadrupolar correlation time

τ_{c}^{Q}

.…”

Section: Theoretical Aspectmentioning

confidence: 99%

Section: Theoretical Aspectmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An NMR relaxation study of magnesium borohydride in solid

Kim

2022

Bulletin Korean Chem Soc

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Effect of the field strength on the MAS NMR spectra: Comparative study between diamagnetic and paramagnetic systems

Shin,

Min,

Ahn

et al. 2024

Bulletin Korean Chem Soc

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Solid‐state NMR spectroscopy has gained increasing attention as a probe to investigate structures and dynamics of various solid materials, in particular, materials for rechargeable batteries. Cathodes and anodes for rechargeable batteries contain unpaired electrons (paramagnetic), which generate localized magnetic fields at molecules. Owing to this paramagnetic interaction, it is often complicated to measure and interpret the NMR spectra of the paramagnetic systems. Thus, understanding the effect of the interaction between unpaired electrons and nuclei is important. NMR spectroscopy at higher magnetic fields has been perceived as beneficial since this can provide higher sensitivity and resolution. However, the response to the magnetic field strength varies depending on the nuclei of interest and material properties because various factors affect NMR characteristics. In this work, we performed a systematic study of the effect of the field strength on the magic angle spinning (MAS) NMR characteristics by comparing diamagnetic and paramagnetic systems at two different magnetic fields. As diamagnetic materials, LiCoO2 (LCO) and Li2O are examined. As paramagnetic materials, LiFePO4(LFP) and lithium nickel manganese cobalt oxides (LiNixMnyCo1–x–yO2) with different compositions are investigated. We have demonstrated that higher signal intensity and narrower linewidths can be obtained at higher magnetic fields for diamagnetic systems, whereas higher signal intensity and better resolution are obtained at lower magnetic fields for paramagnetic systems. Our research will provide systematic and experimental evidence about the field strength dependence of paramagnetic systems and rationalized grounds for choosing proper NMR spectrometers for each material.

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