Reduction of 2-(N,N-dimethylamino)ethyl substituted zirconocene dichlorides: Intramolecular activation of NCH2–H bond. The crystal structures of [η5:η2(C,N)-C5(CH3)4CH2CH2N(CH3)CH2][η5-C5(CH3)5]ZrX (X = Cl, H)

Treatment of zirconocene dichloride [η5-C5(CH3)4CH2CH2N(CH3)2][η5-C5(CH3)5]ZrCl2 (1) with amalgamated magnesium in THF results in cleavage of a C–H bond in one of the methyl groups of the N(CH3)2 fragment yielding [η5:η2(C,N)-C5(CH3)4CH2CH2N(CH3)CH2][η5-C5(CH3)5]ZrH (2). An analogous reduction of [η5-C5(CH3)4CH2CH2N(CH3)2]2ZrCl2 (4) proceeds similarly only in the presence of great excess of P(CH3)3, otherwise no identifiable products are formed. Heterogeneous reaction of the hydride complex 2 with NH4Cl in THF produces the corresponding chloride complex [η5:η2(C,N)-C5(CH3)4CH2CH2N(CH3)CH2][η5-C5(CH3)5]ZrCl (3), with the Zr–CH2 bond retained. The molecular structures of compounds 2 and 3 were established by X-ray diffraction analyses.