Synthesis, Characterization, and Polymerization Activity of the Scandium Half‐Sandwich Complex [Sc(η⁵‐C₅Me₄{SiMe₂(C₆F₅)})(CH₂SiMe₃)₂(THF)]

The scandium half‐sandwich (bis)alkyl complex [Sc( η 5 ‐C 5 Me 4 {SiMe 2 (C 6 F 5 )})(CH 2 SiMe 3 ) 2 (THF)] has been prepared by σ‐bond metathesis between [Sc(CH 2 SiMe 3 ) 3 (THF) 2 ] and C 5 Me 4 H{SiMe 2 (C 6 F 5 )}. Structural characterization by single crystal X‐ray diffraction revealed the typical piano‐stool geometry for this type of complex. The addition of [Ph 3 C][B(C 6 F 5 ) 4 ] resulted in the formation of a half‐sandwich alkyl cation which is an efficient catalyst for the syndiospecific polymerization of styrene in the presence of aluminium alkyls.