Toluene → Cyclopenta-1,3-diene;hafnium(4+);dichloride

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Reaction Steps

1.81 g (5.65 mmol) of hafnium tetrachloride are added to a suspension, cooled to -78° C., of 2.00 g (5.64 mmol) of the dilithium salt (Example 4) in 150 ml of toluene. The orange suspension is allowed to warm to room temperature, and is stirred for a further 2 days in order to complete the reaction. Insoluble constituents are then filtered off via a frit, and the orange-red filtrate is evaporated to dryness on an oil pump. 30 ml of pentane are added to the orange-red residue, and the mixture is stirred vigorously overnight. Removal of the solvent in vacuo gives the hafnocene dichloride as beige powder in a crude product yield of 700 mg (24%). The 1H-NMR spectrum of the crude product shows only one diastereomer.

Provenance & Evidence