Revisiting the Concept of Equivalence in Solid-State NMR

Perras, Frédéric A.; Bryce, David L.

doi:10.1002/9780470034590.emrstm1469

Cited by 9 publications

(49 citation statements)

References 45 publications

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“…The value of J ( 71 Ga, 71 Ga) is determined by measuring the difference between the centers of gravity of each of the two doublet components. In the case of an A 2 spin system (where I =3/2), this splitting is equal to three times J ( 71 Ga, 71 Ga); in the AX case, the splitting is directly equal to J ( 71 Ga, 71 Ga) …”

Section: Resultsmentioning

confidence: 99%

“…The value of J( 71 Ga, 71 Ga) is determined by measuring the differenceb e- tween the centers of gravity of each of the two doublet components.I nt he case of an A 2 spin system (where I = 3/2), this splitting is equal to three times J( 71 Ga, 71 Ga);i nt he AX case, the splitting is directly equal to J( 71 Ga, 71 Ga). [20,21,23] Spectra were fit using two independentm ethods. First, the raw data sets containing both the zero-frequency peak and the lower-intensity doublets of interestw ere fit.…”

Section: Gallium-71nmr Spectroscopymentioning

confidence: 99%

“…Our laboratory has recently reported the development of a series of J ‐resolved solid‐state NMR spectroscopy techniques . These methods are valuable in that they enable the measurement of indirect nuclear spin‐spin ( J ) coupling constants for pairs of quadrupolar nuclei (spin quantum number I >

1 / 2

) in the solid state.…”

Section: Introductionmentioning

confidence: 99%

“…Our laboratory has recently reportedt he developmento f as eries of J-resolved solid-state NMR spectroscopy tech-niques. [20] These methods are valuable in that they enablet he measurement of indirect nuclear spin-spin (J)c oupling constants for pairs of quadrupolar nuclei (spin quantum number I > 1 = 2 )i nt he solid state. Such measurements are often impossible in solution due to rapid quadrupolarr elaxation of many nuclides of interest.I nt he solid state, quadrupolarb roadening of the line shapes for nuclei such as 11 B, 71 Ga, (both I = 3/2) etc.,i so ften orders of magnitude larger than the J coupling constant, thereby obscuring the effects of the latter in as tandard one-dimensional solid-state NMR (SSNMR) spectrum.…”

Section: Introductionmentioning

confidence: 99%

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New Experimental Insight into the Nature of Metal−Metal Bonds in Digallium Compounds: J Coupling between Quadrupolar Nuclei

Kobera

Southern

Rao

et al. 2016

Chemistry A European J

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Multiple bonding between atoms is of ongoing fundamental and applied interest. Here, we report a multinuclear ((1) H, (13) C, and (71) Ga) solid-state magnetic resonance spectroscopic study of digallium compounds which have been proposed, albeit somewhat controversially, to contain single, double, and triple Ga-Ga bonds. Of particular relevance to the nature of these bonds, we have carried out two-dimensional (71) Ga J/D-resolved NMR experiments which provide a direct measurement of J((71) Ga,(71) Ga) spin-spin coupling constants across the gallium-gallium bonds. When placed in the context of clear-cut experimental data for analogous singly, doubly, and triply bonded carbon spin pairs or boron spin pairs, the (71) Ga NMR data clearly support the notion of a different bonding paradigm in the gallium systems. Our findings are consistent with an increasing role across the purported gallane-gallene-gallyne series for classical and/or slipped π-type bonding orbitals.

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Section: Resultsmentioning

confidence: 99%

Section: Gallium-71nmr Spectroscopymentioning

confidence: 99%

1 / 2

) in the solid state.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New Experimental Insight into the Nature of Metal−Metal Bonds in Digallium Compounds: J Coupling between Quadrupolar Nuclei

Kobera

Southern

Rao

et al. 2016

Chemistry A European J

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“…The doublet splittings observed in the DQF J -resolved spectra are dependent on both the magnitude of the J coupling constant and the magnetic equivalency of the nuclear pair under study. ,,, For a pair of magnetically inequivalent nuclei, the J splittings are equal to J , while for a pair of magnetically equivalent nuclei, the J splittings are amplified by a factor of (2 S + 3)(2 S – 1)/4, where S is the spin quantum number . For solids that do not exhibit molecular motions, a pair of nuclei is considered to be magnetically equivalent if they are related by a specific symmetry operation (e.g., C i , S n >1 , C 2 and a mirror plane, or C n>3 along the bond and C 2 relating the nuclei); therefore under favorable conditions the magnitude of the J splittings can directly provide information on the crystallographic symmetry of the system.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Disorder and Electronic Structures of Electron-Precise Dianionic Diboranes: Insights from Solid-State Multinuclear Magnetic Resonance Spectroscopy

et al. 2017

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The J(B,B) coupling constants of various salts of the electron-precise hexacyanodiborane(6) dianion, [B(CN)], were obtained using B double-quantum-filtered (DQF) J-resolved solid-state nuclear magnetic resonance (SSNMR) spectroscopy. Our results show that the magnitude of the DQF J splitting is influenced by both the crystallographic symmetry of the system and the presence of dynamics. The splittings are amplified by a factor of 3 as compared to the corresponding theoretical J coupling constants for cases where (1) there is an absence of dynamics but the boron pairs are crystallographically equivalent or (2) the boron pairs are crystallographically inequivalent but are rendered magnetically equivalent on the time scale of the experiment due to dynamic disorder, which was identified byB and C SSNMR experiments. Consequently, molecular motions need to be taken into consideration when interpreting the results of DQF J-resolved experiments, and conversely, these experiments may be used to identify dynamic disorder. Variable-temperature NMR data support the notion of three different motional processes with correlation times ranging from 10 to 10 s over the temperature range of 248-306 K. When molecular motion and crystallographic symmetry are both accounted for, the J(B,B) coupling constants for various [B(CN)] salts were measured to range from 29.4 to 35.8 Hz, and their electronic origins were determined using natural localized molecular orbital and natural bond orbital analyses. The coupling constants were found to strongly correlate to the hybridization states of the boron orbitals that form the B-B bonds and to the strength of the B-B bonds. This study provides a novel tool to study dynamics in ordered and disordered solids and provides new perspectives on electron-precise dianionic diboranes featuring two-center-two-electron bonds in the context of related compounds featuring multiply and singly bonded boron spin pairs.

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Aufklärung der molekularen Struktur und des Confinements eines in amorphen porösen Polymeren heterogenisierten metallorganischen Katalysators**

Jabbour,

Ashling,

Robinson

et al. 2023

Angewandte Chemie

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Die katalytische Aktivität multifunktionaler, mikroporöser Materialien hängt direkt von der räumlichen Anordnung ihrer Strukturbausteine ab. Trotz großer Erfolge bei dem Design und der Heterogenisierung isolierter, katalytisch aktiver Metallkomplexe in solchen Materialien bleibt ein detailliertes Verständnis ihrer Struktur auf atomarer Ebene und der lokalen Umgebung der aktiven Spezies eine grundlegende Herausforderung, insbesondere wenn diese in amorphe organische Polymere eingebaut sind. Hier zeigen wir, dass durch die Kombination von Computerchemie mit Paarverteilungsfunktionsanalyse, 129Xe NMR‐ und dynamischer Kernpolarisations NMR‐Spektroskopie eine sehr genaue Beschreibung der Molekülstruktur und der Umgebung eines katalytisch aktiven, Rh‐basierten organometallischen Komplexes möglich ist, der in die Poren eines amorphen Bipyridin‐basierten porösen Polymers eingebaut ist. Kleine, aber signifikante Unterschiede in den strukturellen Eigenschaften der Polymere in Abhängigkeit ihrer Funktionalisierung werden hervorgehoben.

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Revisiting the Concept of Equivalence in Solid-State NMR

Cited by 9 publications

References 45 publications

New Experimental Insight into the Nature of Metal−Metal Bonds in Digallium Compounds: J Coupling between Quadrupolar Nuclei

New Experimental Insight into the Nature of Metal−Metal Bonds in Digallium Compounds: J Coupling between Quadrupolar Nuclei

Dynamic Disorder and Electronic Structures of Electron-Precise Dianionic Diboranes: Insights from Solid-State Multinuclear Magnetic Resonance Spectroscopy

Aufklärung der molekularen Struktur und des Confinements eines in amorphen porösen Polymeren heterogenisierten metallorganischen Katalysators**

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