Using a DFT approach we investigated the geometry and the stability of cationic bisindenyl zirconocenes paired up with a counterion and of general formula [rac-Me2Si(1-Ind)2ZrR]+/[MeB(C 6F5)3]- and [rac-Me 2Si(1-Ind)2ZrR]+/[B(C6F 5)4]-, R = -CH2SiMe3 or -CH2CHMe2 groups. The two R groups are differently agostic-bonded to the metal. The calculations evidence rather good similarity when systems bearing the two different R groups are compared in terms of geometry, relative energies, and the ion-pair separation energies. They validate to a large extent the -CH2SiMe3 group as a model of the growing chain in catalytic olefin polymerizations. However, they also underline some geometric differences that should be considered when mechanistic schemes are developed from experiments.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry