Do New Century Catalysts Unravel the Mechanism of Stereocontrol of Old Ziegler−Natta Catalysts?

Stereoselective polymerization of 1-alkenes was discovered 50 years ago. However, a detailed knowledge of the traditional and industrially used Ziegler-Natta catalytic systems is still missing. Recently, well-defined homogeneous and octahedral complexes that polymerize propene to polypropylenes with microstructures extremely similar to those of polymers produced with the traditional catalysts were discovered. These catalysts offer the exciting opportunity to achieve insights into the mechanism of stereocontrol operative with the traditional catalytic systems.