Breaking Symmetry Rules Enhance the Options for Stereoselective Propene Polymerization Catalysis

An
example of breaking “Ewen’s symmetry rule”
for olefin catalysis polymerization is proposed by DFT calculations.
Catalyst precursors with Cs symmetry are suggested to promote the isotactic propene polymerization
by a modification of the active site geometry obtained via coordination
with AlH–alkyl species in solution. The origin of stereocontrol
in olefin polymerization is due to a dual mechanism dictated by the
chiral catalyst. These findings may expand the toolbox for promoting
stereoselective olefin polymerization by transition metal catalysts.