30342-25-7Relevant articles and documents
The effect of solvent accessible surface on Hammett-type dependencies of infinite dilution 29Si and 13C NMR shifts in ring substituted silylated phenols dissolved in chloroform and acetone
Blechta, Vratislav,Sabata, Stanislav,Sykora, Jan,Hetflejs, Jiri,Soukupova, Ludmila,Schraml, Jan
experimental part, p. 128 - 134 (2012/08/07)
Infinite dilution 29Si and 13C NMR chemical shifts were determined from concentration dependencies of the shifts in dilute chloroform and acetone solutions of para substituted O-silylated phenols, 4-R-C6H4-O-SiR′2R″ (R = Me, MeO, H, F, Cl, NMe2, NH2, and CF3), where the silyl part included groups of different sizes: dimethylsilyl (R′ = Me, R″ = H), trimethylsilyl (R′ = R″ = Me), tert-butyldimethylsilyl (R′ = Me, R″ = CMe3), and tert-butyldiphenylsilyl (R′ = C6H5, R″ = CMe3). Dependencies of silicon and C-1 carbon chemical shifts on Hammett substituent constants are discussed. It is shown that the substituent sensitivity of these chemical shifts is reduced by association with chloroform, the reduction being proportional to the solvent accessible surface of the oxygen atom in the Si-O-C link. Copyright
Nuclear Magnetic Resonance Studies of Hydrosilanes. III. A Correlation of Hammett ? Constants with 29Si-H Coupling Constants for Substituted Phenoxy- and (Phenylthio)dimethylsilanes
Watanabe, Hamao,Akaba, Ryoichi,Iezumi, Takao,Nagai, Yoichiro
, p. 2981 - 2985 (2007/10/02)
The 29Si-H coupling constants and Si-H chemical shifts have been determined for a series of substituted phenoxy- and (phenylthio)dimethylsilanes.The J(29Si-H) values are shown to be correlated well with the Hammett ? constants for the substituent on benzene ring in compounds Ar-Y-SiMe2H, where Y=O and S.In comparison with the data for the analogs of the other types of organodimethylsilanes, such as aryldimethylsilanes, substituted benzyldimethylsilanes, and aryltetramethyldisilanes, the present results are discussed on the basis of the substituent effects through theintervening oxygen and sulfur.The transmission efficiency of Y was in the order, S > CH2 ca.SiMe2 > O.For the series of (phenylthio)dimethylsilanes, the J(29Si-H) values observed were larger than those for the predicted ones.This deviation was interpreted in terms of the sulfur d-orbital participation via the electron-acceptor, "?-?" conjugation.