zirconocenedichloride

Zirconocenedichloride, Cp2ZrCl2, is a metallocene complex in which two cyclopentadienyl rings bound to a central zirconium atom are accompanied by two chloride ligands. The compound is a four-coordinate, sandwich-type organ zirconium species, with zirconium in the +4 oxidation state. It is a colorless to pale yellow solid that is typically soluble in nonpolar organic solvents such as toluene or hexanes, and it is sensitive to air and moisture.

Preparation of zirconocenedichloride is commonly accomplished by reaction of zirconium tetrachloride with two equivalents of cyclopentadienyl lithium (LiCp) or another cyclopentadienyl source in an ether solvent, yielding Cp2ZrCl2 and inorganic byproducts (for example LiCl). The product can crystallize as colorless crystals suitable for further processing or storage under inert conditions.

In practice, Cp2ZrCl2 serves mainly as a precatalyst for olefin polymerization and related transformations. Upon activation with cocatalysts such as methylaluminoxane (MAO) or boron-based activators, it generates highly versatile single-site catalysts capable of producing polyethylene and various copolymers with controlled molecular weight and architecture. The complex can also be converted to related derivatives, such as alkyl, hydride, or transmetallated species, by standard organometallic reactions.

Handling and storage require inert atmosphere techniques due to air and moisture sensitivity. Appropriate precautions include dry solvents, glovebox or Schlenk-line techniques, and storage under inert gas to maintain purity and activity.