MO and MM Study of Homogeneous Propylene Polymerization with a Zirconocene Catalyst

Abstract

The stereoregulation in α-olefins polymerization is one of the most important capabilities of Ziegler-Natta catalysts. Homogeneous ansa-metallocene complexes of group 4 metals have been shown to produce isotactic [1–5], syndiotactic [6] and crystalline-amorphous stereoblock polypropylene [1, 7, 8]. Molecular mechanics and ab initio methods have been used to model the catalytic sites [1, 9–13]. The results of these calculations have been used not only to confirm experimental results but also to predict the tacticity obtained with certain catalyst precursors [12]. The design of stereochemical control based on these calculations can help the experimentalists to save time and efforts.