One-Step Block-Copolymerization of Ethylene with Styrene by C₅Me₅/ER-Ligated Samarium(II) Complexes (ER = OAr, SAr)

Groups 3 and 4 single-site catalysts for styrene–ethylene and styrene–α-olefin copolymerization

“…11) obtained by replacement of one of the Cp ligand in lanthanidocene by a monodentate anionic ligand (OAr, SAr, NR 1 R 2 or SiR 3 ) yielded styrene-ethylene block copolymers in a one-step process under mild conditions (toluene, 25 • C, 1 atm) [91]. Homopolystyrene was formed as a by-product but no PE was detected.…”

“…Divalent lanthanide half-sandwich complexes as single-component catalysts used for styrene-ethylene block copolymerization[91][92][93].…”

Synthesis and characterization of anionic lanthanide complexes {[o-(Me3SiN)2C6H4]Ln(MeC5H4)2}{Li(DME)3} (Ln=Yb, Sm, Nd) and their catalytic activity for the polymerization of methyl methacrylate

“…. 1 (3) Following the procedure similar to the synthesis of 1, the reaction of Li 2 -o-(Me 3 SiN) 2 C 6 H 4 (3.91 mmol, 18 mL hexane), NdCl 3 (0.98 g, 3.91 mmol) and MeC 5 H 4 Na (11.67 mL, 7.82 mmol, 0.67 M in THF) in 40 mL THF at 40°C afford 3 as blue-green crystals (2.27 g, 70%). Mp: 127-128°C.…”

“…The anionic Sm(II) complexes of [(C 5 Me 5 )(THF) xSm(ER)(C 5 Me 5 )K(THF) y ] n (ER = OAr, SAr, NR 2 , SiH 3 , CHR 2 ) were reported to be active catalysts for the homopolymerization of ethylene, and styrene, as well as their block copolymerization, whereas the corresponding neutral complexes [(C 5 Me 5 )(THF) x Sm(ER)] are inactive under the same conditions [1]. The ''ate'' allyl complexes of lanthanides K[Ln{C 3 H 3 (SiMe 3 ) 2 } 4 and [Ln{(C 3 H 3 SiMe 3 ) 2 SiMe 2 } 2 -{l-K(THF)}(THF) x ] 1 were found to exhibit much higher activity than the neutral ones Ln[C 3 H 3 (SiMe 3 ) 2 ] 3 for the polymerization of MMA as real single-component catalysts [2].…”

Stereospecific Olefin Polymerization Catalyzed by Metallocene Complexes

“…Some half-metallocenes of lanthanides can catalyze styrene polymerization without co-catalysts, although atactic polystyrene is obtained [86,109,110,111]. A few non-cyclopentadienyl lanthanocenes are known to be capable of syndio and iso-rich polymerization of styrene [112,113], whereas activity and stereoregularity are inferior to Ti catalysts.…”