Oxidative Addition of Silicon-Chloride Bonds to a Zerovalent Ruthenium Center and Direct Generation of an Ethylene Insertion Complex

Abstract

The oxidative addition of a silicon-chloride (Si-Cl) bond to a metal center can be a key reaction step in coordinative silicon chemistry, but this reaction is seldom observed. Herein, we report direct oxidative addition of the Si-Cl bonds of dimethyldichlorosilane (Me2SiCl2) and cyclotrimethylenedichlorosilane [(CH2)(3)SiCl2] to low-valent ruthenium complexes, yielding the 16e(-) chloro(organosilyl)ruthenium complexes [N-3]Ru(Cl)(SiMe2Cl) (4a) and [N-3]Ru(Cl)(SiCl(CH2)(3)) (4b) ([N-3] = 2,6-(MesN = CMe)(2)C5H3N; Mes = 1,3,5-trimethylphenyl; Me = methyl). The reversible reaction of 4a with ethylene yields an 18e(-) ethylene adduct, in which an ethylene is subsequently inserted into a ruthenium-silicon (Ru-Si) bond to produce the 16e(-) complex [N-3]Ru(Cl)(CH2CH2SiMe2Cl) (7). This study provides a good example of the direct generation of an ethylene insertion product, which is an important intermediate in the catalytic reduction of unsaturated molecules.