Living Polymerization by Bis(phenolate) Zirconium Catalysts: Synthesis of Isotactic Polystyrene‐block‐Polybutadiene Copolymers

Abstract

A thermally robust zirconium catalyst containing a tetradentate bis(phenolate) ligand of the (OSSO)-type polymerizes styrene and butadiene in living fashion. The activity follows the order Zr > Hf > Ti. Low polydispersities of the resulting isotactic poly styrenes (PD < 1.10) can be achieved at room temperature, while butadiene is polymerized at temperatures as high as 90 °C to give predominantly trans -1,4-polymer. This allows effi cient preparation of isotactic polystyrene-block -polybutadiene copolymers (iPS-b -PBD).

Polymerization of Norbornene Using Chiral Bis(phenolate) Zirconium Catalysts

“…The microstructure of copolymers can be investigated by analysis of 13 C NMR spectra according to Brintzinger and Tritto et al, Fink et al, and Kaminsky et al Hydrooligo(norbornene)s can also be applied to study their tacticity and behavior in solution . Here, we describe the homo‐ and copolymerization of norbornene using activated chrial bis(phenolato) zirconium dibenzyl complex 1 , previously shown to polymerize styrene with high isospecificity . Despite intriguing reports,[10c,d] there are still no clear structure activity relationships for norbornene polymerization catalysts.…”

“…[ 10 ] Here, we describe the homo-and copolymerization of norbornene using activated chrial bis(phenolato) zirconium dibenzyl complex 1 , previously shown to polymerize styrene with high isospecifi city. [ 11 ] Despite intriguing reports, [ 10c,d ] there are still no clear structure activity relationships for norbornene polymerization catalysts.…”

Engineering of Syndiotactic and Isotactic Polystyrene-Based Copolymers via Stereoselective Catalytic Polymerization

“…Interestingly, BD insertion is mainly trans -1,4 specific in both copolymers, contrasting with the other group 4 catalysts described in this part which copolymerize styrene in a syndiospecific manner and BD in a cis -1,4 specific manner. Same iPS- b -(1,4)PBD with prevalently trans -1,4 structure was also obtained using zirconium complex 22 bearing a similar OSSO-type ligand [ 53 ]. This catalyst was found to have a better thermal robustness than its titanium analogue.…”

Microgels based on isotactic poly(styrene): Synthesis and characterization

“…We investigated microgel synthesis using highly isotactic poly(styrene), accessible by polymerization with organometallic catalysts based on group 4 metals. 14,15 We were interested in the influence of tacticity during microgel synthesis and behavior of those microgels in solution with a view to possible application of such microgels later on as supports for olefin polymerization catalysts. The linear precursor polymers produced in this study are P1 (M n 5 49 kg/mol, Ð 5 1.11), and P2 (M n 5 15 kg/mol, Ð 5 1.03).…”