Enhancement of silicon-29 or tin-119 NMR signals in the compounds M(CH3)(n)Cl(4-n) M = Silicon or tin, n = 4, 3, 2) using proton polarization transfer. Dependence of the enhancement on the number of scalar coupled protons
Author(s)
Doddrell, David M
Pegg, David T
Brooks, William
Bendall, M Robin
Griffith University Author(s)
Year published
1981
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Recently, Freeman and Morris and Morris proposed the use of the nonselective polarization-transfer (PT) pulse train (90xH)-r-( 180XH)(1 80xI)-t-(90j,H) X (90xI)-A-(acquire data, decouple) as a general technique for enhancing the NMR signals from a nucleus I with a low gyromagnetic ratio. The sequence is particularly useful when the relaxation mechanism of nucleus I arises from nonproton dipolar interactions, a consequence of which is negligible nuclear Overhauser enhancement (NOE) after proton decoupling. Fundamental to NMR is the general rule that, provided the relaxation pathway of a nucleus I is dominated by *H-I dipolar ...
View more >Recently, Freeman and Morris and Morris proposed the use of the nonselective polarization-transfer (PT) pulse train (90xH)-r-( 180XH)(1 80xI)-t-(90j,H) X (90xI)-A-(acquire data, decouple) as a general technique for enhancing the NMR signals from a nucleus I with a low gyromagnetic ratio. The sequence is particularly useful when the relaxation mechanism of nucleus I arises from nonproton dipolar interactions, a consequence of which is negligible nuclear Overhauser enhancement (NOE) after proton decoupling. Fundamental to NMR is the general rule that, provided the relaxation pathway of a nucleus I is dominated by *H-I dipolar couplings, the NOE is independent of the number of relaxing protons, being 1 + 7h/27i provided the extreme narrowing limit applies.
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View more >Recently, Freeman and Morris and Morris proposed the use of the nonselective polarization-transfer (PT) pulse train (90xH)-r-( 180XH)(1 80xI)-t-(90j,H) X (90xI)-A-(acquire data, decouple) as a general technique for enhancing the NMR signals from a nucleus I with a low gyromagnetic ratio. The sequence is particularly useful when the relaxation mechanism of nucleus I arises from nonproton dipolar interactions, a consequence of which is negligible nuclear Overhauser enhancement (NOE) after proton decoupling. Fundamental to NMR is the general rule that, provided the relaxation pathway of a nucleus I is dominated by *H-I dipolar couplings, the NOE is independent of the number of relaxing protons, being 1 + 7h/27i provided the extreme narrowing limit applies.
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Journal Title
Journal of the American Chemical Society
Volume
103
Issue
3
Subject
Chemical Sciences