Bimetallic Transition Metal-Zirconocene Complexes from Zirconium Hydrides

Bimetallic Transition Metal-Zirconocene Complexes from Zirconium Hydrides 

The bis-zirconocene complex CpjClZrCHjCHjZrCpjCl has been isolated upon double hydrozirconation of acetylene with 1 [102]. Recently, the preparation of a heterogeneous bis-zirconocene catalyst was succesfully achieved from zirconocene dichloride complexes containing alkenyl or alkynyl substituents [224]. 

C02-Bridged bimetallic zirconocene complexes have been formed from 1 and metallocarboxylic acids [229]. Reachon of 1 with metal enolates Cp(CO)3WCHR COX (X = OEt, Me, Ph) gives Cp(CO)3WCH(R )CH(R)OZrCp2(Cl). The structure for R = H and R = Me was solved by an X-ray analysis and the chemical reactivity of these organometallic products have been studied [230]. 

Note that reaction of the vinyl chloride complex Tp Rh(CNCH2 Bu)(CH=CH2)Cl with [Cp2ZrH2]2 did not give the hydrozirconation reaction on the vinyl group but led quantitatively to the formation of the vinyl hydride complex Tp Rh(CNCH2 Bu) (CH=CH2)H [231]. 

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