| Texto completo | |
| Autor(es): |
Cobo, Marcio Fernando
[1]
;
Achilles, Anja
[2]
;
Reichert, Detlef
[2]
;
deAzevedo, Eduardo Ribeiro
[1]
;
Saalwaechter, Kay
[2]
Número total de Autores: 5
|
| Afiliação do(s) autor(es): | [1] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13560970 Sao Paulo - Brazil
[2] Univ Halle Wittenberg, Inst Phys NMR, D-06120 Halle - Germany
Número total de Afiliações: 2
|
| Tipo de documento: | Artigo Científico |
| Fonte: | JOURNAL OF MAGNETIC RESONANCE; v. 221, p. 85-96, AUG 2012. |
| Citações Web of Science: | 15 |
| Resumo | |
A specific separated-local-field NMR experiment, dubbed Dipolar-Chemical-Shift Correlation (DIPSHIFT) is frequently used to study molecular motions by probing reorientations through the changes in XH dipolar coupling and T-2. In systems where the coupling is weak or the reorientation angle is small, a recoupled variant of the DIPSHIFT experiment is applied, where the effective dipolar coupling is amplified by a REDOR-like pi-pulse train. However, a previously described constant-time variant of this experiment is not sensitive to the motion-induced T-2 effect, which precludes the observation of motions over a large range of rates ranging from hundreds of Hz to around a MHz. We present a DIPSHIFT implementation which amplifies the dipolar couplings and is still sensitive to T-2 effects. Spin dynamics simulations, analytical calculations and experiments demonstrate the sensitivity of the technique to molecular motions, and suggest the best experimental conditions to avoid imperfections. Furthermore, an in-depth theoretical analysis of the interplay of REDOR-like recoupling and proton decoupling based on Average-Hamiltonian Theory was performed, which allowed explaining the origin of many artifacts found in literature data. (C) 2012 Elsevier Inc. All rights reserved. (AU) | |
| Processo FAPESP: | 08/11675-0 - Métodos de RMN para estudos de materiais com alta mobilidade molecular: aplicações a polímeros eletroluminescentes e nanocompostos de intercalação |
| Beneficiário: | Márcio Fernando Cobo |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado Direto |
| Processo FAPESP: | 09/18354-8 - Dinâmica e estrutura de sistemas poliméricos estudados por ressonância magnética nuclear |
| Beneficiário: | Eduardo Ribeiro de Azevedo |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |