Chlorolanthanocene-dialkylmagnesium systems for styrene bulk polymerization and styrene-ethylene block copolymerization

Controlled polyethylene chain growth on magnesium catalyzed by lanthanidocene: A living transfer polymerization for the synthesis of higher dialkyl-magnesium

“…In this work, such functionalization by carbon dioxide has been performed and the block copolymerization with polar monomers by an anionic mechanism was successfully tested. This in situ alkylating method that affords lanthanide active species for polymerization also proved to be useful with other monomers [43], as well as using other lanthanidocene precursors [44] and alkylating agents [45]. It should also be emphasized that recently, this process has been successfully applied to produce alkoxyamine-terminated PE's and sulfur-functionalized PE's, useful as macroinitators for controlled radical polymerization and for RAFT polymerization, respectively [46].…”

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

“…Reversible chain-transfer reactions between chlorolanthanidocenes and dialkylmagnesium compounds were also exploited to achieve styrene-ethylene block copolymers [98]. Indeed, complex Cp* 2 NdCl 2 Li(OEt 2 ) 2 in combination with MgR 2 , previously established as an efficient ethylene polymerization catalytic system [99][100][101], was also active for the formation of oligostyrenes.…”

“…as [CH 2 CH(Ph)] x − [CH 2 CH 2 ] y with x = 10-13 and y = 3-20 (corresponding to 38-65 mol% styrene incorporation) were synthesized [98].…”

Developments of rare earth metal catalysts for olefin polymerization

“…A two component system, Cp à 2 Ndðl-ClÞ 2 LiðOEt 2 Þ 2 (11)/BuEtMg, was reported to polymerize styrene, but the reaction mechanism is yet not clear [23]. In order to improve reactivities of rare earth catalysts toward 1-olefins, a series of ansa-metallocene type complexes have been studied (Scheme 2).…”

“…Divalent samarium complexes, Cp à 2 Sm and Cp à 2 SmðTHFÞ 2 (23), was reported to show high activity for ethylene polymerization [14] to give polymers with relatively low molecular weight. These complexes reacts with 1-olefins to form stable p-allyl complexes [14,31].…”