Efficient living polymerization of 1-hexene by Cp*TiMe2(O-2,6-iPr2C6H3)-borate catalyst systems at low temperature

Fluorinated bis(phenoxy–imine) Ti complexes with MAO: Remarkable catalysts for living ethylene and syndioselective living propylene polymerization

“…Considering that the MAO used as the cocatalyst is a potential chain transfer agent, and that living olefin polymerization can normally only be achieved using a borate cocatalyst instead of MAO, the fact that living ethylene polymerization with MAO was exhibited by the system is highly significant. Because of the highly controlled living nature of 9/MAO, a living propagating species can be observed with 1 H NMR spectroscopy [-(CH 2 ) n -at d 1.32 ppm and -CH 2 -CH 3 at d 0.97 ppm as a triplet in toluene-d 8 ] [35l].…”

“…As a result, a number of useful catalysts have been developed, which initiate the room-temperature living polymerization of 1-hexene or other higher a-olefins and the stereoselective living polymerization of 1-hexene and vinylcyclohexane [3][4][5][6][7][8]. There are, however, a limited number of examples of catalysts that can carry out the living polymerization of ethylene and/or propylene at room temperature, in spite of the structural simplicity and industrial importance of ethylene-and propylene-based polymers [9][10][11][12][13][14][15][16][17][18][19].…”

Effect of Cyclopentadienyl and Anionic Ancillary Ligand in Syndiospecific Styrene Polymerization Catalyzed by Nonbridged Half-Titanocenes Containing Aryloxo, Amide, and Anilide Ligands: Cocatalyst Systems

“…The fact is also interesting because efficient living 1-hexene polymerization affording high molecular weight poly(1-hexene) with narrow molecular weight distribution [e.g., M n ) 186.5 × 10 4 , M w /M n ) 1.27] was reported in the presence of the Cp*TiMe 2 (O-2,6-i Pr 2 C 6 H 3 )/Al i Bu 3 /Ph 3 CB(C 6 F 5 ) 4 -catalyst system. 31 Table 9 summarizes results concerning styrene concentration dependence toward catalytic activity. 32 A linear first-order relationship between the catalytic activity and monomer concentration was observed (Figure 7), and an attempt to control the chain transfer reaction (and then to develop the catalyst system for a living polymerization) was unsuccessful, although the M w /M n value became narrow under low styrene concentration conditions (M w /M n ) 1.31-1.37).…”

Olefin Polymerization with Half-Metallocene Catalysts

“…The observed activity was extremely low when 1-hexene polymerization was conducted in the presence of Cp*TiMe 2 (O-2,6-i Pr 2 C 6 H 3 ) and B(C 6 F 5 ) 3 -Al i Bu 3 , whereas the polymerization took place in a quasi-living manner with significant activity at -30°C when [Ph 3 C][B(C 6 F 5 ) 4 ] was used in place of B(C 6 F 5 ) 3 [112]. The reaction with B(C 6 F 5 ) 3 in toluene-d 8 [113].…”

“…Half-titanocenes such as Cp*TiF 3 , Cp*Ti(OMe) 3 and (indenyl)TiCl 3 are known to be efficient catalyst precursors for syndiospecific styrene polymerization ( [10,42,111,112,[188][189][190][191][192][193][194], Example concerning syndiospecific styrene polymerization by half-titanocene complex-borate catalyst [195][196][197]). However, these catalysts showed low activities in ethylene/styrene copolymerization and the resultant polymers afforded a mixture of polyethylene (PE), syndiotactic polystyrene (SPS) and the copolymer (E/S copolymer) (Examples in ethylene/styrene copolymerization [194][195][196][197][198]).…”