Transition Metal Catalysts for Syndiotactic Polystyrene

Computational Analyses of the Effect of Lewis Bases on Styrene Polymerization Catalyzed by Cationic Scandium Half-Sandwich Complexes

“…Syndio -PS (syndiotactic polystyrene) discovered by Ishihara and co-workers in 1986 currently plays an irreplaceable role in industrial production and in our daily lives because of its high crystallization rate, good electrical properties, and excellent heat and chemical resistance . Numerous homogeneous group 4 and late transition metal single-site catalysts have been synthesized and applied successfully to the syndiospecific styrene polymerization . In the recent decade, novel rare-earth metal catalysts have been developed for highly efficient and selective (co)­polymerization of styrene .…”

Olefin Polymerization with Half-Metallocene Catalysts

“…It is thus clear that these observed facts are significantly unique compared to those previously demonstarated in the copolymerization using ordinary metallocenes or linked half-titanocenes (Copolymerization with norbornene [86] Syndiotactic polystyrene (SPS) is a unique polymeric material due to its high melting point (T m =270°C), high crystallinity, low density, low dielectric constant, and high chemical resistance toward organic solvents [10,40,109,110, Example concerning syndiospecific styrene polymerization by half-titanocene complexborate catalyst [185][186][187]). This polymer cannot be prepared by free radical, anionic or ordinary Ziegler-Natta processes, but can be prepared by the syndiospecific polymerization using various half-titanocenes (Scheme 2.10), Cp'TiX 3 or Cp'TiX 2 (Y) (Cp' = cyclopentadienyl group; X = halogen, alkoxo, alkyl etc.…”

“…Example concerning syndiospecific styrene polymerization by half-titanocene complex-borate catalyst [185][186][187], Examples of a mechanistic studies for styrene polymerization [227][228][229]). The oxidation state of the active species has been invoked as cationic Ti(III) (Scheme 2.11, left) ( [218,[221][222][223][224][225][226], Example Cp': cyclopentadienyl fragment Scheme 2.11 Proposed catalytically-active species for syndiospecific styrene polymerization [38] concerning syndiospecific styrene polymerization by half-titanocene complexborate catalyst [185][186][187][191][192][193], whereas the cationic Ti(IV) species would play a role for the ethylene/styrene copolymerization ( [41], Related publications for synthesis and reactivity of cationic half-titanocene alkyl complexes containing aryloxo ligand [97,98], [220]). In contrast, Tomotsu (Idemitsu) insisted a possibility that neutral Ti(III) species [226], [Cp'Ti(R)(Y)(styrene)] (Y = anionic ligand), should play a role as the active species (Scheme 2.11, right) [10,[40][41][42].…”

“…), which are efficient catalyst precursors for syndiospecific styrene polymerization ( [10,40,109,110,218,[221][222][223][224][225][226], Example concerning syndiospecific styrene polymerization by half-titanocene complex-borate catalyst [185][186][187]), afforded a mixture of polyethylene (PE), syndiotactic polystyrene (SPS) and the copolymer (E/S copolymer) in the ethylene/styrene (co)polymerization (Copolymerization with styrene with efficient styrene incorporation or in a living manner [93], The product distribution and the [194][195][196][197][198]). The product distribution and the activity in (co)polymerization using a CpTiX 3 -MAO catalyst system is thus highly sensitive to the anionic donor ligand (X=Cl, CH 2 Ph, OCH 3 , OCH 2 Ph etc.…”

Synthesis and Characterization of Syndiotactic Polystyrene-Polyethylene Block Copolymer

“…Syndiotactic polystyrene (sPS) is one of the most significant achievements of homogeneous polyinsertion catalysis [1,2]. Besides its employment as engineering plastic [3] thanks to a high melting temperature combined with favourable crystallization kinetics, sPS appears also as a smart polymer due to its nanoporous crystalline structure [4,5,6].…”