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DFT calculations of indirect 29Si-1H spin-spin coupling constants in organoalkoxysilanes.
Ambati, Jyothirmai; Rankin, Stephen E.
Afiliação
  • Ambati J; Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky 40506-0046, USA.
J Phys Chem A ; 114(16): 5279-86, 2010 Apr 29.
Article em En | MEDLINE | ID: mdl-20361771
The performance of four basis sets (6-311+G(2d,p), IGLO-III, cc-PVTZ, and 6-31G) is evaluated in order to find a quantum mechanical technique that can be used to accurately estimate (29)Si-(1)H spin-spin coupling constants in organoalkoxysilanes. The 6-31G basis set with the B3LYP functional is found to be an accurate, efficient, and cost-effective density functional theory method for predicting spin-spin coupling constants of organoalkoxysilanes. Knowledge of these scalar coupling constants and their dependence on structural variations is important to be able to fine-tune NMR experiments that rely on polarization transfer among nuclei, such as (29)Si distortionless enhancement by polarization transfer (DEPT). The effects of size and the number of unhydrolyzable alkyl groups attached to silicon and the effects of substitution of alkoxy groups with hydroxyl groups on (29)Si-(1)H spin-spin coupling constants are investigated using this DFT method. The results show that the predicted scalar coupling between silicon and organic groups depends weakly on the degree of hydrolysis of the alkoxysilanes. The effectiveness of this method is also illustrated for the determination of spin-spin coupling constants in a species containing a siloxane bond.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Teoria Quântica / Silanos / Silício / Hidrogênio Tipo de estudo: Prognostic_studies Idioma: En Ano de publicação: 2010 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Teoria Quântica / Silanos / Silício / Hidrogênio Tipo de estudo: Prognostic_studies Idioma: En Ano de publicação: 2010 Tipo de documento: Article