Insertion stereochemical factors

The meso triad-based, enantiomorphic site control type of stereochemical errors, mm, are formed whenever the said balanced nonbonded steric interaction is perturbed, and the correct alignment of the substituents of the three main participants (ligand, polymer chain and monomer) is not materialized perfectly. In such a case, a monomer with wrong face is inserted and a unit with inverted configuration is enchained. The ability of occasional reverse face selectivity emanates firom the inherent structural factors of the metallocene-based catalyst. It is independent of monomer concentration and cormter-ion pairing nature however, it is dependent on polymerization temperature. 

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