Synthesis and reactivity of asymmetrically substituted ansa-bridged zirconocene complexes: X-ray crystal structures of [Zr{R(H)C(η 5-C 5Me 4)(η 5-C 5H 4)}Cl 2] (R = Bu n, Bu t) and [Zr{Bu n(H)C(η 5-C 5Me 4)(η 5-C 5H 4)}(CH 2Ph) 2

Abstract

The dialkyl complexes, [ Zr { R ( H ) C ( η 5 - C 5 Me 4 ) ( η 5 - C 5 H 4 ) } R 2 ′ ] (R = Pr i , R′ = Me ( 2a), CH 2Ph ( 3a); R = Bu n , R′ = Me ( 2b), CH 2Ph ( 3b); R = Bu t , R′ = Me ( 2c), CH 2Ph ( 3c); R = Ph, R′ = Me ( 2d), CH 2Ph ( 3d)), have been synthesized by the reaction of the ansa-metallocene dichloride complex, [Zr{R(H)C(η 5-C 5Me 4)(η 5-C 5H 4)}Cl 2] (R = Pr i ( 1a), Bu n ( 1b), Bu t ( 1c), Ph ( 1d)), and two molar equivalents of the alkyl Gringard reagent. The insertion reaction of the isocyanide reagent, CNC 6H 3Me 2-2,6, into the zirconium–carbon σ-bond of 2 gave the corresponding η 2-iminoacyl derivatives, [Zr{R(H)C(η 5-C 5Me 4)(η 5-C 5H 4)}{η 2-MeC NC 6H 3Me 2-2,6}Me] (R = Pr i ( 4a), Bu n ( 4b), Bu t ( 4c), Ph ( 4d)). The molecular structures of 1b, 1c and 3b have been determined by single-crystal X-ray diffraction studies.