Mono- and di-cyclopentadienyl zirconium derivatives containing the dimethylsilylcyclopentadienyl ligand. Agostic linear Si-H-Zr interaction in the molecular structure of [Zr{eta(5)-C5H4(SiMe2H)}Cl-3](2)

Dimethylsilyl substituted mono- and di-cyclopentadienyl zirconium chlorides have been prepared and their reactions with amido and alkyl reagents studi ed. The silylcyclopentadienes C5H5(SiMe2H) 1, C5H4(SiMe2H)(2) 2 and C5H4(Si Me3)(SiMe2H) 3 can be prepared by reaction of Na(C5H5) with the appropriate chlorosilane reagent. The lithium salt Li[C5H4(SiMe2H)] reacts with ZrCl4 or [Zr(C5H5)Cl-3] to give the metallocene complexes [Zr(C5H4R){C5H4(SiMe2H) }Cl-2] (R=SiMe2H 4 or H 5) whereas the reaction of the disilylcyclopentadie ne C5H4(SiMe2H)(2) with ZrCl4 afforded the monocyclopentadienyl complex [Zr {C5H4(SiMe2H)}Cl-3] 6, which exchanges the Si-H and Zr-Cl bonds. The reacti on of 6 with lithium amides produces different products depending on the ba sicity of the nitrogen atom and the steric demands of its amido substituent s. The reaction with LiN(SiMe3)(2) and LiNH(2,6-Me2C6H3) afforded the corre sponding amido zirconium complexes [Zr{C5H4(SiMe2H)}(NRR')Cl-2] (R=R'=SiMe3 7; R=H, R'=2,6-Me2C6H3 8), but in the case of the reaction with (LiNHBu)-B u-t the known cyclopentadienylsilylamido derivative [Zr(eta (5),eta (1)-(C5 H4SiMe2NBu)-Bu-t)Cl-2] was formed. The monoamido, diamido and dialkyl dicyc lopentadienyl complexes [Zr(C5H4R){C5H4(SiMe2H)}X(Y)] (R=SiMe2H 9 or H 10, X=Cl, Y=(NHBu)-Bu-t; R=SiMe2H 11 or H 12, X=Y=(NHBu)-Bu-t; R=SiMe2H 13 or H 14, X=Y=Me) have been synthesized by reaction of 4 and 5 with the appropri ate amido or methyl reagent. Compound 9 reacts with a stoichiometric amount of water with selective hydrolysis of the Zr-amido bond to give the corres ponding mu -oxo dinuclear complex [{Zr[C5H4(SiMe2H)](2)Cl}(2)(mu -O)] 15. T he molecular structure of [Zr{C5H4(SiMe2H)}Cl-3] 6 was established by X-ray crystallography. Compound 6 is a dimer, in the solid state, in which dimer ization occurs through Zr-H-Si agostic interactions and two chloride bridge s.