NMR Studies of Isolated Spin Pairs in the Solid State

Power, William P.; Wasylishen, Roderick E.

doi:10.1016/s0066-4103(08)60275-6

Cited by 50 publications

(32 citation statements)

References 273 publications

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“…Consider a single PH spin system in a solid compound (16 [4] In this equation H is the proton gyromagnetic ratio, r PH is the phosphorus-proton internuclear separation (approximately 1Å for a directly bonded proton) and PH is the angle of the PH vector with respect to B O . The ± sign results from the fact that the local field may either add to or subtract from the laboratory field B O depending on whether the proton dipole is aligned with or opposed to the direction of B O , which is almost equally possible.…”

Section: Proton Dipolar Broadeningmentioning

confidence: 99%

“…For the case where the spin I = 1/2 nucleus is 31 P and the quadrupolar nucleus is a metal atom M, the relevant coupling constants are the metal nuclear Zeeman interaction Z = M hB/2 (where M is the gyromagnetic ratio of the M nucleus), the metal nuclear quadrupole coupling constant = e 2 qQ/h (e = electronic charge, q = electric field gradient at the M nucleus, Q = quadrupole moment of the M nuclues), the phosphorus-metal dipolar coupling constant D Eq. [16], r = M-P…”

Section: Gold Complexesmentioning

confidence: 99%

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Aspects of equivalence as illustrated by phosphine complexes of transition metals

Nelson¹

2001

Concepts Magn. Reson.

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ABSTRACT:The various types of symmetry-related nuclei present in transition metal complexes of phosphines are discussed. Differences between the solution and the solid states are considered. Examples of spectra are presented to illustrate the relationships between the types of equivalences and observed spectral line shapes. An introduction to solid-state NMR spectroscopy is followed by descriptions of spectra that illustrate some of the types of information, which may be obtained from NMR spectroscopy of solid samples.

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Section: Proton Dipolar Broadeningmentioning

confidence: 99%

Section: Gold Complexesmentioning

confidence: 99%

Aspects of equivalence as illustrated by phosphine complexes of transition metals

Nelson¹

2001

Concepts Magn. Reson.

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“…However, to determine the orientation of the principal components of the CS tensor in the molecular reference frame requires further experimentation. One technique of relevance to the present work involves introducing a second spin (X) in the vicinity of the I = % nucleus (A) such that the two spins are dipolar coupled (6). Such a spin system can be described as an isolated spin-pair (AX).…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…6 MHz on a Bruker AMX-400 spectrometer (Bo = 9.4 T). For the MSL, samples were packed into 7 mm 0.d.…”

Section: Solid-state Nmr Spectroscopymentioning

confidence: 99%

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A solid-state ¹³C NMR and theoretical investigation of carbonyl and thiocarbonyl carbon chemical shift tensors

Kirby¹,

Lumsden²,

Wasylishen³

1995

Can. J. Chem.

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The carbon chemical shift tensors of the carbonyl and thiocarbonyl groups of acetamide, thioacetamide, thioacetanilide, 4'-methoxyacetanilide, and 4'-methoxythioacetanilide have been experimentally determined using dipolar -chemical shift solid-state 13c NMR spectroscopy. The magnitudes of the three principal components of the carbon chemical shift tensors are found to exhibit marked variations between the carbonyl and thiocarbonyl functionalities. However, in contrast to the conclusions of an earlier comparative investigation involving benzophenone and thiobenzophenone, the orientations of the principal axis systems of these chemical shift tensors are found to be similar. These experimental results represent the first complete characterizations of the carbon chemical shift tensor in organic thiocarbonyls. The results of our ab initio GIAO and LORG calculations of carbon chemical shielding tensors in formaldehyde, thiofomaldehyde, formamide, and thioformamide as well as in acetamide and thioacetamide are in qualitative agreement with experiment. The findings of the present investigation provide conclusive evidence that the well-known isotropic deshielding of the carbon nucleus in the C=S group relative to C=O is primarily attributable to the decreased energy associated with the o tt T* excitation within the thiocarbonyl fragment. This result is in contrast with the conventional interpretation that the deshielding originates from a red shift in the C=S HOMO-LUMO n + T* transition.Key words: chemical shift tensors, solid-state I3C NMR, carbonyls, thiocarbonyls, ab initio calculations.RksumC : Utilisant les deplacements chimiques dipolaires de la spectroscopie RMN du I3c 2i I'ttat solide, on a determine exptrimentalement les tenseurs des dtplacements chimiques du carbone des groupes carbonyle et thiocarbonyle des acttamide, thioacetamide, thioacttanilide, 4'-mCthoxyacCtanilide et 4'-mCthoxythioacttanilide. On a trouvt que les amplitudes des trois principales composantes des tenseurs des dtplacements chimiques du carbone presentent des variations importantes entre les fonctions carbonyles et thiocarbonyles. Toutefois, en opposition avec les conclusions tirkes 2i partir d'une ttude comparative anttrieure impliquant la benzophenone et la thiobenzophtnone, on a trouvt que les orientations des principaux axes de rtftrence de ces tenseurs des dCsplacements chimiques sont semblables. Ces resultats exptrimentaux representent les premihres caractkrisations complktes du tenseur du dtplacement chimique des thiocarbonyles organiques. Les rtsultats de nos calculs ab initio GIAO et LORG des tenseurs d'tcran chimique du carbone dans les formaldthyde, thiofomaldChyde, formamide, thiofomamide ainsi qu'acttamide et thioacttamide sont en accord qualitatif avec les rtsultats expCrimentaux. Les observations faites dans le present travail fournissent des bases concluantes qui permettent d'attribuer le deblindage bien connu du noyau du carbone dans le groupe C=S par rapport au C=O 2i une diminution de l'energie associee B une e...

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Chemical Shift Tensor Measurement in Solids

Orendt

2007

Encyclopedia of Magnetic Resonance

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NMR Studies of Isolated Spin Pairs in the Solid State

Cited by 50 publications

References 273 publications

Aspects of equivalence as illustrated by phosphine complexes of transition metals

Aspects of equivalence as illustrated by phosphine complexes of transition metals

A solid-state ¹³C NMR and theoretical investigation of carbonyl and thiocarbonyl carbon chemical shift tensors

Chemical Shift Tensor Measurement in Solids

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NMR Studies of Isolated Spin Pairs in the Solid State

Cited by 50 publications

References 273 publications

Aspects of equivalence as illustrated by phosphine complexes of transition metals

Aspects of equivalence as illustrated by phosphine complexes of transition metals

A solid-state 13C NMR and theoretical investigation of carbonyl and thiocarbonyl carbon chemical shift tensors

Chemical Shift Tensor Measurement in Solids

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A solid-state ¹³C NMR and theoretical investigation of carbonyl and thiocarbonyl carbon chemical shift tensors