Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The electronic effect parameter σ for XYZSi-R compounds as silyl hydrides XYZSiH, alkoxysilanes XYZSiOL (L = alkyl or substituted alkyl) and α-carbofunctional silanes XYZSiCH₂Y (Y = Cl and OL) having X, Y and Z substituents of various electron-donating and electronaccepting ability has been established by a linear regression analysis of the IR and NQR data on these compounds. It is shown that no universal scale of the σ constant for silyl XYZSi-groups can be established. The electronic effect transmission of the X, Y and Z substituents through the silicon depends on the type of the intramolecular interaction between the silicon and the R group and the electronic effect parameter of silyl groups should be treated as a variable whose exact value depends on the nature of the particular molecule.