INVESTIGADORES
PROVASI patricio Federico
artículos
Título:
Stereochemical dependence of NMR geminal spin?spin coupling constants
Autor/es:
RUBEN H. CONTRERAS; PATRICIO F. PROVASI; FRANCISCO P. DOS SANTOS; CLAUDIO F. TORMENA
Revista:
MAGNETIC RESONANCE IN CHEMISTRY
Editorial:
JOHN WILEY & SONS LTD
Referencias:
Lugar: LOndres; Año: 2008 vol. 47 p. 113 - 120
ISSN:
0749-1581
Resumen:
In this work it was sought to explore the versatility of geminal spin?spin coupling constants, 2JXY SSCCs, as probes forstereochemical studies. A set of compounds, where their experimental 2JXY SSCCs through the X?C?Y molecular fragment arepredicted to be sensitive to hyperconjugative interactions involving either bonding or antibonding orbitals containing the Ccarbon atom (?coupling pathway?), were analyzed. SSCC calculations were performed for some selected examples using thesecond order polarization propagator approximation (SOPPA)method or within the DFT-B3LYP framework. Hyperconjugativeinteractions were calculated within the Natural Bond Orbital (NBO) approach. Results are condensed in two qualitative rules:Rule IM ? hyperconjugative interactions transferring charge into the coupling pathway yield a positive increase to the Fermicontact (FC), contribution to 2KXY reduced spin?spin coupling constants (RSSCC), and Rule IIM ? hyperconjugative interactionstransferring charge from the coupling pathway yield a negative increase to the FC contribution to 2KXY RSSCC.