Precisely Controlled Polymerization of Styrene and Conjugated Dienes by Group 3 Single‐Site Catalysts

This Review aims at a comprehensive overview on the recent stereospecific control polymerizations by group 3 metal complexes based catalytic systems in combination with aluminum alkyls and organoborates etc. co‐catalysts. The involved monomers include styrene and substituted styrenes, and the conjugated dienes like isoprene and butadiene, and their derivatives. The syndio‐ and iso‐selective polymerizations of styrene, unmasked polar styrenes and the copolymerizations of styrene with conjugated dienes and polar styrenes are summarized. The factors of influencing the catalytic activity and selectivity are discussed. The regio‐ and stereo‐ selective polymerizations of conjugated dienes, polar diene derivatives and their copolymerizations are reviewed. The relationship between catalyst structure and polymerization activity, the mechanism of stereo‐selective polymerization and the influence of different cocatalysts are discussed. A solo performance: In this Review, a variety of group 3 single‐site catalysts for the precise control of regio‐ and stereo‐ selective (co)polymerizations of styrene and conjugated dienes are systematically introduced. The activities, selectivities, molecular weights and molecular weight distributions dependent on the structure of the catalysts, cocatalysts, and reaction conditions etc. are detailed discussed.