121Sb Moessbauer and 1H and 13C NMR Spectroscopic Studies of a Series of Organoantimony(V) Compounds, R3SbX2

Article abstract of DOI:10.1246/bcsj.59.3085

The 121Sb Moessbauer spectroscopic and the 1H and 13C NMR nuclear magnetic resonance studies have been performed for a series of organoantimony(V) compounds: R3SbX2 (R=CH3, C6H5, p-CH3C6H4; X=F, Cl, Br, I).For the trimethylantimony dihalides, the isomer shifts and quadrupole coupling constants of the 121Sb Moessbauer spectra indicated that the withdrawal of the bonding electrons from the antimony atom along Sb-X increased, as the electronegativity of the halogen increased.The chemical shifts of the 1H and 13C NMR spectra showed that the electron population around the methyl group increased with increasing electronegativity of halogen.For phenyl and p-tolyl derivatives, both 121Sb Moessbauer and 13C NMR data showed a trend similar to the methyl compounds.The results suggest that the electron cloud around the antimony atom spreads, with an increase in the electronegativity of the halogen, not only toward the halogen atoms but also toward the plane perpendicular to the bonding direction with the halogen atoms.