η:η-Alkynyl-Bridged W−Si Complexes: Formation, Structure, and Reaction with Acetone

Reactions of (η5-C5Me4R)(CO)2(MeCN)WMe (R = Me, Et) with HPh2SiC⋮CtBu gave the novel alkynyl-bridged W−Si complexes, (η5-C5Me4R)(CO)2W(μ-η1:η2-C⋮CtBu)(SiPh2) (R = Me, Et), whose alkynyl ligands bridge the tungsten and silicon atoms in an η1:η2-coordination mode. The structures of these complexes were fully characterized, including X-ray crystallography. Treatment of (η5-C5Me5)(CO)2W(μ-η1:η2-C⋮CtBu)(SiPh2) with acetone resulted in acetone insertion into the silicon−alkynyl linkage followed by intramolecular C−H activation of the tBu group to give the chelate-type alkyl−alkene complex,