Steric Parameters for Substituents Bound to Atoms of Silicon and Some Other Elements of the Third Period

Abstract

The kinetics of a tetraethoxysilane reaction with n-butylmagnesium chloride, stoichiometrically monosolvated with isopropyl ether or with methyl tert-butyl ether, was studied in toluene. The pseudo–first-order rate constants determined at a great excess of Grignard reagent were used for separation of the appropriate equilibrium and rate constants. Equilibrium constants for five alkyl ether ligands at the magnesium center are in an excellent correlation with isosteric E_S(Si) parameters. It was concluded that these constants should be applicable to all elements of the third period of the periodic table.

Keywords:

• Grignard reaction
• isosteric parameters
• silanes
• solvation effects

Acknowledgments

This work was financially supported by the Estonian Ministry of Education and Research (Grant SF 0180064s08).