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)
摘要:
Treatment of zirconocene dichloride [eta(5)-C-5(CH3)(4)CH2CH2N(CH3)(2)][eta(5)-C-5(CH3)(3)]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 [eta(5):eta(2)(C,N)C-5(CH3)(4)CH2CH2N(CH3)CH2][eta(5)-C-5(CH3)(2)]ZrH (2). An analogous reduction of [eta(5)-C-5(CH3)(4)CH2CH2N(CH3)(2)](2)ZrCl2 (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 [eta(5):eta(2)(C,N)-C-5(CH3)(4)CH2CH2N(CH3)CH2][eta(5)-C-5(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. (c) 2005 Elsevier B.V. All rights reserved.