Reaction of Alkenylzirconocenes with Dialkylzirconocenes:  Unexpected Formation of Bimetallic (μ-Alkynyl)zirconocene Complexes

Reaction of alkenylzirconocenes Cp<sub>2</sub>ZrX(MeCCH<sub>2</sub>) (X = Cl, Br) with dialkylzirconocenes Cp<sub>2</sub>ZrR<sub>2</sub> (R = Me, Et, Bu) yielded the unexpected bimetallic zirconocene complexes Cp<sub>2</sub>Zr(μ-X)(μ-C⋮CCH<sub>3</sub>)ZrCp<sub>2</sub> (X = Cl, Br). Its structure (X = Cl) was determined by X-ray crystallography. The monitoring of the reaction of Cp<sub>2</sub>ZrBu<sub>2</sub> with Cp<sub>2</sub>ZrBr(MeCCH<sub>2</sub>) revealed that the first step of this reaction was an exchange reaction of the Bu and Br groups.