Synthesis and Reactivity of Alkylzirconium Complexes Incorporating Asymmetrically Substituted ansa Ligands − X‐ray Crystal Structure of [Zr{Me 2 Si(η 5 ‐C 5 Me 4 )(η 5 ‐C 5 H 3 Me)}(CH 2 Ph)Cl]

The monoalkyl complexes [Zr{Me 2 Si(η 5 ‐C 5 Me 4 )(η 5 ‐C 5 H 3 R)}(R′)Cl] [R = Me, R′ = CH 2 Ph ( 1 ); R = Me, R′ = CH 2 SiMe 3 ( 2 ); R = i Pr, R′ = CH 2 Ph ( 3 ); R = i Pr, R′ = CH 2 SiMe 3 ( 4 ); R = SiMe 3 , R′ = CH 2 Ph ( 5 ); R = SiMe 3 , R′ = CH 2 SiMe 3 ( 6 )] have been synthesized by the reaction of the corresponding ansa ‐metallocene dichloride complex and 1 equiv of the alkyl Grignard reagent. Dialkyl complexes with large alkyl groups only formed for the zirconocene complex containing the ansa ligand Me 2 Si(η 5 ‐C 5 Me 4 )(η 5 ‐C 5 H 4 ) and with the benzyl substituent giving [Zr{Me 2 Si(η 5 ‐C 5 Me 4 )(η 5 ‐C 5 H 4 )}(CH 2 Ph) 2 ] ( 7 ). When the alkyl substituent is CH 2 SiMe 3 only the monoalkyl derivative, [Zr{Me 2 Si(η 5 ‐C 5 Me 4 )(η 5 ‐C 5 H 4 )}(CH 2 SiMe 3 )Cl] ( 8 ), was formed. The insertion reaction of the isocyanide reagent CNC 6 H 3 Me 2 ‐2,6 into the zirconium−carbon σ‐bond of complexes 1 − 8 gave the corresponding η 2 ‐iminoacyl compound [Zr{Me 2 Si(η 5 ‐C 5 Me 4 )(η 5 ‐C 5 H 3 R)}{η 2 ‐R′C=NC 6 H 3 Me 2 ‐2,6}Cl] [R = Me, R′ = CH 2 Ph ( 9 ); R = Me, R′ = CH 2 SiMe 3 ( 10 ); R = i Pr, R′ = CH 2 Ph ( 11 ); R = i Pr, R′ = CH 2 SiMe 3 ( 12 ); R = SiMe 3 , R′ = CH 2 Ph ( 13 ); R = SiMe 3 , R′ = CH 2 SiMe 3 ( 14 ); R = H, R′ = CH 2 SiMe 3 ( 16 )] and [Zr{Me 2 Si(η 5 ‐C 5 Me 4 )(η 5 ‐C 5 H 4 )}{η 2 ‐PhCH 2 C=NC 6 H 3 Me 2 ‐2,6}(CH 2 Ph)] ( 15 ). The molecular structure of 1 has been determined by single‐crystal X‐ray diffraction studies. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)