Observation of Solid-State <sup>103</sup>Rh NMR by Cross-Polarization

Phillips, Brian L.; Houston, Jacqueline R.; Feng, Jian; Casey, William H.

doi:10.1021/ja057347s

Cited by 12 publications

(10 citation statements)

References 18 publications

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“…52 Although 103 Rh is 100% naturally abundant, it has a very low Larmor frequency of only 12.8 MHz at 9.4 T (Table S1). To the best of our knowledge, there has been only one previous of 103 Rh solid-state NMR spectra, 53 most likely because of the challenges associated with the low-γ of 103 Rh.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Enhancing the Sensitivity of Solid-State NMR Experiments with Very Low Gyromagnetic Ratio Nuclei with Fast Magic Angle Spinning and Proton Detection

et al. 2018

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Many transition metals commonly encountered in inorganic materials and organometallic compounds possess NMR-active nuclei with very low gyromagnetic ratios (γ) such as Y,Rh, Ag, andW. A low-γ leads to poor NMR sensitivity and other experimental challenges. Consequently, nuclei with low-γ are often impossible to study with conventional solid-state NMR methods. Here, we combine fast magic angle spinning (MAS) and proton detection to enhance the sensitivity of solid-state NMR experiments with very low-γ nuclei by 1-2 orders of magnitude. Coherence transfer between H and low-γ nuclei was performed with low-power double quantum (DQ) or zero quantum (ZQ) cross-polarization (CP) or dipolar refocused insensitive nuclei enhanced by polarization transfer (D-RINEPT). Comparison of the absolute sensitivity of CP NMR experiments performed with proton detection with 1.3 mm rotors and direct detection with 4 mm rotors shows that proton detection with a 1.3 mm rotor provides a significant boost in absolute sensitivity, while requiring approximately 1/40 of the material required to fill a 4 mm rotor. Fast MAS and proton detection were applied to obtain Y andRh solid-state NMR spectra of organometallic complexes. These results demonstrate that proton detection and fast MAS represents a general approach to enable and accelerate solid-state NMR experiments with very low-γ nuclei.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Enhancing the Sensitivity of Solid-State NMR Experiments with Very Low Gyromagnetic Ratio Nuclei with Fast Magic Angle Spinning and Proton Detection

et al. 2018

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“…3(b). Also included are the 103 Rh{ 1 H} CP kinetics data for an aqua complex of a dihydroxy-bridged Rhdimer measured previously, [44] which exhibits weak heteronuclear coupling owing to the small value of γ Rh−103 . These data lie reasonably close to the correlation derived from Mg(II)-cit and Sr(II)-cit.…”

Section: Zn(ii)-dhb and Kaolinitementioning

confidence: 99%

“…An example is the T Rh−H for the H-dense Rh-dimer, which is estimated accordingly to be 18 ms, a value reasonably close to the experimentally measured 13 ms, considering the spin locking nutation frequency used in the 103 Rh{ 1 H} CP/MAS experiments was much smaller than that applied in the current work. [44] Estimation of the T IS could be especially useful in CP/MAS experiments for low-γ nuclei (e.g. 103 Rh), which generally exhibit long T IS and low sensitivity, making it difficult to optimize the experimental parameters.…”

Section: Citrate Defects In Calcitementioning

confidence: 99%

NMR spectroscopy of citrate in solids: cross‐polarization kinetics in weakly coupled systems

Feng¹,

Lee²,

Kubicki³

et al. 2008

Magnetic Reson in Chemistry

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Solid-state NMR spectroscopy is a potentially powerful method for obtaining molecular level structural information crucial for understanding the specific relationship between calcite crystals and occluded organic molecules that are important in biomineralization and biomimetic materials. In this work, a method is developed based on cross-polarization/magic angle spinning (CP/MAS) NMR to measure the heteronuclear distances and obtain structural information for large intracrystalline citrate defects in a synthetic calcite/citrate composite. Using compounds with well-characterized crystal structures, Mg(II) citrate and Sr(II) citrate, a correlation is established between T(IS), the CP time, and M(2) (IS), the van Vleck heteronuclear dipolar second moment, which contains distance and structural information. This correlation is supported by peak assignments obtained from calculations of the (13)C chemical shifts for crystalline Mg(II) citrate. On the basis of T(IS) (-1) versus M(2) (IS) correlation, measurement of T(IS) for carbonate ions associated with citrate defects in a calcite((13)C-enriched)/citrate coprecipitate yields an estimate for the distance between citrate and the nearest carbonate carbon that indicates close spatial proximity and provides useful constraints for future computational study. The applicability of T(IS) (-1) versus M(2) (IS) correlations to other weakly coupled spin-1/2 systems is discussed in terms of the effects of (1)H homonuclear dipolar coupling, using the CP kinetics of Zn(II) dihydroxybenzoate and kaolinite for comparison. The results suggest a limited range of correlation constants and indicate that quantitative information can be obtained from CP/MAS kinetics obtained under similar experimental conditions.

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“…Therefore, for all but the most symmetric sites, SSBs are generated over a significant spectral width that would be too large to uniformly excite; in addition the T 1 relaxation of rhodium is likely to be between hundreds and thousands of seconds. Using the CP method to observe 103 78 The solid-state MAS 207 Pb chemical-shielding parameters for lead in materials containing oxy-anions, plumbates and plumbites, as well as in PbSe were reported. 79 In the absence of X-ray data, static NMR spectra of 65 Cu provided useful information on the structural units of the Cu(I) cores from quadrupolar interactions.…”

Section: Solid-state Nmr Spectroscopymentioning

confidence: 99%

Physical methods and techniques : NMR spectroscopy

Edgar¹

2007

Annu. Rep. Prog. Chem., Sect. B: Org. Chem.

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This review covers the period 2005-2007, with a handful of leading references to important older reviews. Nuclear Magnetic Resonance spectroscopy continues to evolve, with sensitivity, selectivity, rapid acquisition, and high-throughput automation driving innovation. Solid-state NMR spectroscopy has exploded in importance and has been used to investigate small organic molecules and large biomolecules. A new high-resolution heteronuclear corellation method is described (H2BC) and a 38 year old method is resurrected (DEFT). Novel NMR techniques such as fast acquisition methods, optical detection, detection in mT fields (2 Hz), and MAS MRI of a live mouse are highlighted. I am endebted to the great and the good whose work has been reported here. All credit is theirs; errors, omissions and blame are all mine.

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Observation of Solid-State ¹⁰³Rh NMR by Cross-Polarization

Cited by 12 publications

References 18 publications

Enhancing the Sensitivity of Solid-State NMR Experiments with Very Low Gyromagnetic Ratio Nuclei with Fast Magic Angle Spinning and Proton Detection

Enhancing the Sensitivity of Solid-State NMR Experiments with Very Low Gyromagnetic Ratio Nuclei with Fast Magic Angle Spinning and Proton Detection

NMR spectroscopy of citrate in solids: cross‐polarization kinetics in weakly coupled systems

Physical methods and techniques : NMR spectroscopy

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Observation of Solid-State 103Rh NMR by Cross-Polarization

Cited by 12 publications

References 18 publications

Enhancing the Sensitivity of Solid-State NMR Experiments with Very Low Gyromagnetic Ratio Nuclei with Fast Magic Angle Spinning and Proton Detection

Enhancing the Sensitivity of Solid-State NMR Experiments with Very Low Gyromagnetic Ratio Nuclei with Fast Magic Angle Spinning and Proton Detection

NMR spectroscopy of citrate in solids: cross‐polarization kinetics in weakly coupled systems

Physical methods and techniques : NMR spectroscopy

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Observation of Solid-State ¹⁰³Rh NMR by Cross-Polarization