Collect. Czech. Chem. Commun. 2004, 69, 2281-2296

The Solvent Effects on Kinetics and Mechanism of Zinc or Cadmium Halide Catalyzed Reactions of Hydrosilanes with Hydroxylic Reagents

Jerzy J. Chruściel

Institute of Polymer and Dye Technology, Faculty of Chemistry, Technical University, 90-924 Łódź 40, Poland


The effect of solvent composition on reaction rates was studied by a kinetic method for reactions of Et3SiH with Ph2Si(OH)2 in the presence of ZnCl2 in a mixture of DMF and THF or Et3SiH with PhCOOH and cadmium bromide CdBr2 in DMF-1,4-dioxane and DMF-THF. A decrease in reaction rates with decreasing polarity of the medium (and its dielectric constant) has been observed. The kinetic order of dehydrocoupling reaction with respect to DMF was determined from kinetic studies. The constants of nucleophilic catalysis with DMF (λ) were found. The role of DMF in the mechanism of dehydrocoupling of hydrosilanes with hydroxylic reagents in the presence of ZnX2 and CdX2 halides (X = Cl, Br, I) is discussed.

Keywords: Hydrosilanes; Silanes; Silanols; Hydroxylic reagents; Dehydrocoupling; Solvent effects; Reaction mechanisms; Nucleophilic substitutions.

References: 66 live references.