Zirconocene dichloride

• Bis (cyclopentadienyl ) zirconium (IV) dichloride
• Dichlorobis ( η5 -cyclopentadienyl ) zirconium
• Bis ( η5 - cyclopentadienyl) zirconium dichloride

Colorless crystals

Fixed

1.785 g · cm -3

242-245 ° C

Soluble in organic solvents, to hydrolysis in water

1.555 ± 0.005 at the melting temperature

Attention

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Zirconocene dichloride is a organozirconium compound consisting of a zirconium - central atom and two cyclopentadienyl ligands and two chloride ligands. Zirconocene dichloride is a diamagnetic, white solid which is relatively stable in air.

Preparation and Structure

Zirconocene dichloride can be prepared from a zirconium ( IV) chloride - THF complex, and sodium - cyclopentadienyl:

The closely related compound Cp2ZrBr2 was first described by Birmingham and Wilkinson.

The structure of the compound is similar to a fold blade, the Cp -rings are not parallel, and the average M Cp -Cp angle ( from the surface center point) is 128 °. The Cl -Zr -Cl angle of 97.1 ° is wider than in Niobocendichlorid ( 85.6 ° ) and Molybdocendichlorid (82 °). Knowledge about this trend helped to demonstrate the orientation of the HOMO in this class of complexes.

Reactions

Zirconocene dichloride reacts with lithium aluminum hydride to Cp2ZrHCl, the Schwartz reagent:

Since lithium is a strong reducing agent, the dihydro complex Cp2ZrH2 can be caused by too great a reaction, it can be converted by dichloromethane to Schwartz reagent.

Zirconocene dichloride also finds industrially as a catalyst or pre-catalyst in polymerization reactions application. Such polymers also are available, which are not accessible using standard Ziegler-Natta catalysts and have, for example, special tacticity, molecular weight or molecular weight distribution.