Random- and Block-Copolymerization of 1,3-Butadiene with Styrene Based on the Stereospecific Living System:  (C₅Me₅)₂Sm(μ-Me)₂AlMe₂/Al(i-Bu)₃/[Ph₃C][B(C₆F₅)₄]

Cationic Alkyl Rare‐Earth Metal Complexes Bearing an Ancillary Bis(phosphinophenyl)amido Ligand: A Catalytic System for Living cis‐1,4‐Polymerization and Copolymerization of Isoprene and Butadiene

“…However, similar to the heterogeneous industrial catalysts, such binary or ternary catalyst systems generally lack “livingness” and yield polymers with rather broad molecular‐weight distributions. On the other hand, lanthanide metallocene‐based catalyst systems, such as [(C 5 Me 5 ) 2 Sm(μ‐Me) 2 AlMe 2 ]/Al( i Bu) 3 /[Ph 3 C][B(C 6 F 5 ) 4 ],4b have been found to afford polymers with both high cis ‐1,4 selectivity (up to 99 %) and a narrow molecular‐weight distribution, or “livingness” ( M w / M n =1.20–1.23), in the polymerization of butadiene under appropriate conditions,4 however, the polymerization of isoprene has not been achieved in a “living” fashion with such catalyst systems 4f. Very recently, the combination of a Nd/Mg heterotrimetallic allyl complex with methylaluminoxane (MAO) was reported to show both high cis ‐1,4 selectivity (95–99 %) and a relatively narrow molecular‐weight distribution ( M w / M n =1.3–1.7) for the polymerization of isoprene 5.…”

Ultimately Specific 1,4‐cis Polymerization of 1,3‐Butadiene with a Novel Gadolinium Catalyst

“…[4] Especially effective was (C 5 Me 5 ) 2 Sm-[(m-Me)A1Me 2 (m-Me)] 2 Sm(C 5 Me 5 ) 2 (1a) [5] in combination with two additional cocatalysts, i Bu 3 Al and [Ph 3 C][B-(C 6 F 5 ) 4 ], which produced polybutadiene with a 1,4-cis selectivity of 99.0% and M w /M n ¼ 1.20-1.23 at À20 8C. [6] In our Communication: Novel complexes [(C 5 Me 5 ) 2 Ln][B-(C 6 F 5 ) 4 ] (Ln ¼ Pr, Nd, or Gd) were prepared, which in combination with i Bu 3 Al efficiently induce highly 1,4-cisspecific polymerization of butadiene. The activity of the Gd complex/ i Bu 3 Al system is high enough to exhibit good catalytic activity even at low temperature.…”

Stereospecific Olefin Polymerization Catalyzed by Metallocene Complexes

“…Kaita and Hou reported samarocene-catalyzed highly 1,4-cis-selective butadiene polymerization. This is a rare example of stereospecific catalysts of non-bridged metallocene complexes for the polymerization of butadiene [160,161,162] (Fig. 19).…”