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Titolo:
FULL H-1 AND C-13 NMR CHEMICAL-SHIFT ASSIGNMENT OF 1-PYRENYL SUBSTITUTED OLIGOSILANES AS A TOOL TO DIFFERENTIATE BETWEEN INTRAMOLECULAR THROUGH-SPACE AND THROUGH-BOND GROUND-STATE INTERACTIONS
Autore:
GELAN J; ADRIAENSENS P; VANDERZANDE D; DECLERCQ D; HERMANS E; DESCHRYVER FC;
Indirizzi:
LIMBURGS UNIV CENTRUM,MAT RES INST,DIV CHEM,UNIV CAMPUS GEBOUW D B-3590 DIEPENBEEK BELGIUM KATHOLIEKE UNIV LEUVEN,DEPT CHEM B-3001 HEVERLEE BELGIUM
Titolo Testata:
Journal of the American Chemical Society
fascicolo: 17, volume: 116, anno: 1994,
pagine: 7877 - 7884
SICI:
0002-7863(1994)116:17<7877:FHACNC>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
FORMING BICHROMOPHORIC MOLECULES; BRIDGES; DIMERS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
24
Recensione:
Indirizzi per estratti:
Citazione:
J. Gelan et al., "FULL H-1 AND C-13 NMR CHEMICAL-SHIFT ASSIGNMENT OF 1-PYRENYL SUBSTITUTED OLIGOSILANES AS A TOOL TO DIFFERENTIATE BETWEEN INTRAMOLECULAR THROUGH-SPACE AND THROUGH-BOND GROUND-STATE INTERACTIONS", Journal of the American Chemical Society, 116(17), 1994, pp. 7877-7884

Abstract

A detailed analysis strategy is developed to realize a full proton and carbon NMR chemical shift assignment of a series of substituted 1-pyrenylsilane derivatives mainly based on direct and long-range proton-carbon chemical shift 2D-correlation spectroscopy. The proton and carbon chemical shifts of two dimethylaniline substituted 1-pyrenylsilane derivatives (P2D and P3D) and a pentafluorophenyl substituted 1-pyrenylsilane derivative (P2F) are compared to nonsubstituted 1-pyrenylsilanederivatives of different silane chain lengths (P2, P3, and P6). Accurate C-13 shifts Of these compounds are shown to be an important tool to study the character of the ground state interactions in these compounds. They are more sensitive than H-1 shifts, and the interpretation is more straightforward since there is no confusion with possible chemical shift anisotropy effects. The analysis leads to the conclusion that changes in local electron density, caused by a donor group as dimethylaniline or by an acceptor group as pentafluorophenyl, are transferred to the pyrene moiety primarily via ''through space'' electrostatic polarization effects rather than donor-acceptor effects. The observed changes in chemical shift point to the presence of a significant contribution of folded conformations in the ground state for the alpha,omega-substituted silane derivatives.

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Documento generato il 29/09/20 alle ore 04:24:45