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

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 (Me 2 SiCl 2 ) and cyclotrimethylenedichlorosilane [(CH 2 ) 3 SiCl 2 ] to low-valent ruthenium complexes, yielding the 16e - chloro(organosilyl)ruthenium complexes [N 3 ]Ru(Cl)(SiMe 2 Cl) ( 4a ) and [N 3 ]Ru(Cl)(SiCl(CH 2 ) 3 ) ( 4b ) ([N 3 ] = 2,6-(MesN═CMe) 2 C 5 H 3 N; 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)(CH 2 CH 2 SiMe 2 Cl) ( 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.