Active Species of Post-Metallocene Polymerization Catalysts Based on First-Row Transition Metals
In the last decades, the design of novel catalysts for coordination-insertion polymerization of olefins has been one of the major trends of polymerization chemistry. In spite of extensive studies, the nature of catalytically active sites of post-metallocene catalysts were mostly speculative, the actual polymerization mechanisms remaining largely hypothetical. In this contribution, we summarize our research of the last 10 years, directed at the spectroscopic detection and identification of transient species in post-metallocene catalyst systems based on coordination complexes of Ti, V, Fe, Co, Ni. Special attention will be given the detection and identification of the true metal-polymeryl chain-carrying species.