A General Model to Explain the Isoselectivity of Olefin Polymerization Catalysts

Stereoselective olefin polymerization promoted by Ziegler–Natta catalysts is a very active field thanks to the recent implementation of high-throughput screening techniques. These techniques have identified a large set of novel nonmetallocene ligands for polymerization catalysis. This chapter updates standard models that have been used to explain the origin of stereoselectivity for propene polymerization promoted by ansa-metallocene systems. Density functional theory calculations on selected nonmetallocene ligands suggest a different origin of stereocontrol for propene polymerization within the enantiomorphic site control framework. Some perspectives on the ligand design for targeted materials are indicated, emphasizing the “synergic effect” of standard and new models to achieve a very high isoselectivity in propene polymerization.