Noncovalent Interactions in Olefin Polymerization Catalysis Promoted by Transition Metals

Two case histories are reported where noncovalent interactions play an important role in olefin polymerization catalyzed by transition metals. In the first example, by using DFT calculations, the influence of α-agostic interactions on the stereoselectivity of propene insertion reactions and their contribution to developing new models for the isotactic stereocontrol achieved with nonmetallocene catalysts are considered. In the second example, experimental and theoretical results aimed at explaining the role of noncovalent interactions (such as F⋯H or F⋯M, where M = metal center) in living olefin polymerization promoted by Group 4 nonmetallocene systems and also the chain-branching formation of polyethylene obtained with late transition metals are summarized.