Metallocenium-monoalkyl cation

Crystal Structure of the Metallocenium-Monoalkyl Cation and the Structure of the Putative Active Site... 

The stereorigid bridged metallocene dichloride 1, as depicted in Fig. 2, is a prochiral molecule and possesses bilateral symmetry. The activatirm of metallocene dichloride 1 leads to the formation of enantiomeric metallocenium-monoaUcyl cationic species that are both electron-deficient and coordinatively unsaturated and structurally very similar to the enantiomeric molecule depicted in Fig. 3. These enantiomeric metallocenium-monoalkyl species have the necessary vacant coordination position and energetically low lying, accessible empty fragment orbitals to be used for coordination and activation of incoming propylene molecules via interaction with their available n orbitals. 

The cationic metallocenium-monoalkyl species [21] are composed of equal numbers of R and S mirror-image related enantiomers and have monomer re si jt-face selective properties (Fig. 5). 

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