DFT Studies on the Early-Transition-Metal-Catalyzed Polymerization of Polar Monomers with a Methylene Spacer between Vinyl and Functional Groups

Direct (co)polymerization of polar monomers is the most economical and efficient method to prepare functional olefins. However, because some early-transition-metal catalysts are very sensitive to polar functional groups due to Lewis acid–base interactions, metal catalysts are highly sensitive to functional groups of polar monomers. Thus, (co)polymerization of polar monomers has been a long-standing academic research challenge in polymer science, especially for early-transition-metal complexes. Herein, we computationally demonstrate that the polymerization of polar monomers with methylene spacers between the vinyl and functional groups by half-sandwich Ti(III) and Zr(III) complexes could be achieved without any Lewis-acidic masking reagents or bulky protective substituents. Such a polymerization follows the mechanism of heteroatom-chelating olefin insertion. We expect that the current results could provide significant information to propose efficient and accessible early-transition-metal catalysts for the synthesis of functional polyolefins.