MMA Polymerization with Group 4 Alkyl‐Free 14‐Electron d0 Species.

Cationic 1,2 and 1,3 doubly constrained geometry di(silylamido)cyclopentadienyl zirconium complexes, whilst being group 4 alkyl‐free 14‐electron d0 species, promote the polymerization of MMA. Different cocatalysts such as B(C6F5)3, Al(C6F5)3 and [CPh3][B(C6F5)4] have been employed to generate the catalytic species in order to collect experimental evidence to propose the polymerization mechanism that these cationic compounds may follow. By systematically studying the role of the active species, this study establishes that the mechanism may be different from the traditional coordination‐addition mechanism proposed for group 4 metal complexes in MMA polymerizations. [ABSTRACT FROM AUTHOR]