Synthesis and characterization of new alkoxide and aryloxide derivatives of titanium and zirconium. X-ray molecular structure of [ZrCp2(OC6F5)2]

Abstract

Lithium or sodium alkoxides MOR (R double bond; length as m-dashCH2CHdouble bond; length as m-dashCMe2; M double bond; length as m-dash Li1; Na2; R double bond; length as m-dash C6F5; M double bond; length as m-dash Li3 were prepared by reaction of the alcohols with n-butyl lithium or sodium metal in hexane. Reaction of a hexane suspension of3 with SiClMe, afforded SiMe3(OC6F5)4, whereas the reaction of 3 equivalents of C6F5OH with AlMe3 in hexane led to Al(OC6F5)35. Compounds1 or2 react with one equivalent of [TiCp*Cl2Me] (Cp*double bond; length as m-dash C5Me5) in toluene to give [TiCp*ClMe(OCH2CHdouble bond; length as m-dashCMe2)]6. Complex6 reacts with AlEtCl2 to give quantitatively [TiCp*Cl3]. In the presence of water, the hydrolysis of6 takes palce giving the μ-oxo compound [{(TiCp*Cl)(μ − O)}3]. [TiCp*Cl2Me] reacted with an excess of the alcohol C6F5OH to give [TiCp*(OC6F5)3]7. [ZrCp2Cl2] reacted with two equivalents of pentaflurophenol in the presence of aniline to give the dialkoxide [ZrCp2(OC6F5)2]8. When the same reaction was carried out in a 1:1 molar ratio, a mixture of8 and the chloroalkoxide [ZrCp2Cl(OC6F5)]9 was obtained. A cleac reaction takes place when the μ-oxo compound [(ZrCp2Me)2(μ-O)] is treated with two equivalents of pentaflurophenol, leading to the isolation of the alkoxo complex [{ZrCp2(OC6F5)}2(μ-O)]10. The methylalkoxo derivative [ZrCp2Me(OC6F5)]11, was obtained by rection of [ZrCp2ClMe] with one equivalent of3. Alternative methods can be also be followed to synthesize8 and11. The crystal and molecular structure of8 has been determined by X-ray diffraction methods. The most interesting feature of this structure is the disposition of the (C6F5) ring planes, which are located practically on the reflection plane defined by O(1), Zr(1) and O(1)′.