Substituent Effects on Silicon of Bridged Tetramethylcyclopentadienyl−Phenoxy Titanium Complexes for Controlling the Regiochemistry and Molecular Weight in 1-Olefin Polymerization

Senda, Taichi; Hanaoka, Hidenori; Hino, Takahiro; Oda, Yoshiaki; Tsurugi, Hayato; Mashima, Kazushi

doi:10.1021/ma901678u

Cited by 19 publications

(15 citation statements)

References 14 publications

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“…9 In addition, the content of 2,1-insertion units in the polypropylenes produced by 5/ i Bu 3 Al/Ph 3 CB(C 6 F 5 ) 4 and 6/ i Bu 3 Al/Ph 3 CB(C 6 F 5 ) 4 catalyst systems is lower than that of the polypropylene obtained with I/ i Bu 3 Al/Ph 3 CB(C 6 F 5 ) 4 catalyst system, which should be resulted from that the coordination environment around the central metal in complexes 5 and 6 is more crowded than that in complex I. 27 Polymerization of 1-hexene and ENB Homopolymerization reactions of 1-hexene and ENB were also investigated with 5/ i Bu 3 Al/Ph 3 CB(C 6 F 5 ) 4 and 6/ i Bu 3 Al/Ph 3 CB (C 6 F 5 ) 4 catalyst systems, and the results are listed in Table 3. Both catalyst systems were found to show reasonable catalytic activity although only low molecular weight polymers were obtained from the polymerization reactions of the two monomers.…”

Section: Propylene Polymerizationmentioning

confidence: 81%

Synthesis and structures of (R)-cyclopentadienyl-binaphthoxy titanium(iv) complexes and catalytic properties for olefin polymerization

Wang

et al. 2012

Dalton Trans.

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Two new chiral pre-ligands, (R)-3,3'-bis(tetramethylcyclopentadienyl)-2,2'-bismethoxy-1,1'-bisnaphthalene (1) and (R)-3-tetramethylcyclopentadienyl-2,2'-bismethoxy-1,1'-bisnaphthalene (2), were synthesized by reaction of (R)-3,3'-dilithium-2,2'-bismethoxy-1,1'-bisnaphthalene with 2,3,4,5-tetramethyl-2-cyclopentenone at room temperature. Treatment of the pre-ligands 1 and 2 with butyllithium and Me(3)SiCl first, and subsequently with TiCl(4) (2 and 1 equiv for 1 and 2, respectively) afforded a binuclear complex (R)-3,3'-bis[(tetramethylcyclopentadienyl)trichlorotitanium]-2,2'-bismethoxy-1,1'-bisnaphthalene (3) and a mononuclear complex (R)-3-(tetramethylcyclopentadienyl)trichlorotitanium-2,2'-bismethoxy-1,1'-bisnaphthalene (4) in moderate yields. Complexes 3 and 4 were further converted into constrained geometry complexes (R)-1,1'-bis{2,2'-naphthoxy-3,3'-bis[(tetramethylcyclopentadienyl)dibromotitanium]} (5) and (R)-1-(2-naphthoxy)-1'-(2'-naphthol)-3-(tetramethylcyclopentadienyl)dibromotitanium (6) by treatment with BBr(3). The pre-ligands 1 and 2 were characterized by (1)H and (13)C NMR and high resolution mass spectroscopy (HRMS), and the new titanium complexes 3-6 were characterized by (1)H and (13)C NMR and elemental analyses. Molecular structures of 4, 5, and 6 were determined by single-crystal X-ray diffraction analysis. Complexes 4, 5, and 6 all have a pseudo-octahedral coordination environment and adopt a three-legged piano stool geometry around the titanium atom in their solid state structures. When activated with Al(i)Bu(3) and Ph(3)CB(C(6)F(5))(4), the chiral complexes 5 and 6 show moderate catalytic activities for propylene, 1-hexene, and 5-ethylidene-2-norbornene (ENB) polymerization and ethylene/1-hexene copolymerization. The polymers produced by the chiral 5/(i)Bu(3)Al/Ph(3)CB(C(6)F(5))(4) catalyst system from the 1-hexene, and ENB polymerization and ethylene/1-hexene copolymerization with high comonomer contents exhibit optical activity.

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Section: Propylene Polymerizationmentioning

confidence: 81%

Synthesis and structures of (R)-cyclopentadienyl-binaphthoxy titanium(iv) complexes and catalytic properties for olefin polymerization

Wang

et al. 2012

Dalton Trans.

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“…To specifically target “constrained-geometry” group 4 metal complexes containing phenoxy-amidinate and phenoxy-guanidinate ligands, we carried out alkane and amine elimination reactions between the corresponding bifunctional diprotic pro-ligands and homoleptic MR 4 (R = CH 2 Ph, M = Zr; R = NMe 2 , M = Hf) precursors. Previous investigations have shown that such approaches are efficient one-step routes toward compounds of the type L 2 MR 2 . ,, …”

Section: Resultsmentioning

confidence: 99%

“…In this line, Marks and others showed that bridged systems of type 2 (Scheme ) are highly performing in ethylene and propylene homopolymerizations and ethylene/norbornene copolymerization . Other heteroleptic complexes incorporating linked cyclopentadienyl-phenoxide scaffolds ( 3 ; Scheme ) were found to be effective catalyst precursors for the homo- and copolymerizations of ethylene and α-olefins, such as 1-hexene …”

Section: Introductionmentioning

confidence: 99%

Synthesis and Structural Diversity of Group 4 Metal Complexes with Multidentate Tethered Phenoxy-Amidine and Phenoxy-Amidinate Ligands

2012

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International audienceThe coordination chemistry of the multidentate tethered amidine-phenol {4,6-tBu2C6H2O(2-C(NR)═NR}H2 ({LONR}H2, R = iPr, 2,6-iPr2C6H3 (Ar)) and new guanidine-phenol {4,6-tBu2C6H2ON(C6H5)(2-C(NR)═NR}H2 ({LON(Ph)NiPr}H2) pro-ligands with group 4 metals has been studied. σ-Bond and salt metathesis reactions were explored to coordinate these (pro)ligands onto zirconium and hafnium. Alkane elimination reactions between {LONR}H2 and Zr(CH2Ph)4 afforded mixed-ligand monobenzyl {LOHNR}{LONR}Zr(CH2Ph) (R = iPr; 1) and monoligand tribenzyl {LOHNAr}Zr(CH2Ph)3 (R = Ar; 2) complexes, respectively. Alkane and amine elimination reactions between {LON(Ph)NiPr}H2 and Zr(CH2Ph)4 or Hf(NMe2)4 unexpectedly resulted in cleavage of the ligand backbone and eventual isolation of {(Ph)NC6H2(tBu)2O}Zr{(iPrN)2CCH2Ph}2 (3) and {(Ph)NC6H2(tBu)2O}Hf{(iPrN)2CNMe2}2 (4), respectively. Salt metathesis reactions between {LONR}Li2 and ZrCl4(THF)n (n = 0, 2), conducted in 1:1 ratios, led upon crystallization to diverse chloro complexes: [{LONiPr}ZrCl]3(μ3-O)(μ3-Cl) (5), [{LONAr}2ZrCl(μ2-Cl)]2[{LHONAr}ZrCl(μ2-Cl)](μ3-OH) (6), and {LOHNAr}ZrCl3(THF) (7). Similar salt metathesis reactions between the monolithium salts {LHONR}Li and ZrCl4, conducted in 2:1 ratios, allowed the selective preparation of bis(phenoxy-amidine) complexes with pendant amino groups {LOHNR}2ZrCl2 (R = iPr, 8; R = Ar, 9). All complexes were authenticated by elemental analysis, X-ray crystallography, and NMR spectroscopy. Complexes 5, 6, 8, and 9, upon activation with MAO, showed poor to moderate productivities (4-172 (kg of PE) mol-1 h-1) in the polymerization of ethylene, giving linear polymers with large polydispersities

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“…The substituents on the silicon bridge were found to have a significant impact on the regioselectivity of 1‐olefin enchainment and owing to a high probability of chain termination after 2,1‐insertion also on molecular weights. Increasing the steric bulk of these substituents hampers 2,1‐insertion in propylene homopolymerization and leads to higher molecular weights 67. Further catalyst optimization lead to complexes bearing thiophene‐fused cyclopentadienyl moieties68 or a fluorenyl ligand,69 which were highly active in producing high‐molecular‐weight ethylene/1‐hexene copolymers with high 1‐hexene content even at temperatures up to 210 °C.…”

Section: Cyclopentadienyl–amido Catalystsmentioning

confidence: 99%

Post‐Metallocenes in the Industrial Production of Polyolefins

2014

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Research on “post‐metallocene” polymerization catalysis ranges methodologically from fundamental mechanistic studies of polymerization reactions over catalyst design to material properties of the polyolefins prepared. A common goal of these studies is the creation of practically useful new polyolefin materials or polymerization processes. This Review gives a comprehensive overview of post‐metallocene polymerization catalysts that have been put into practice. The decisive properties for this success of a given catalyst structure are delineated.

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Substituent Effects on Silicon of Bridged Tetramethylcyclopentadienyl−Phenoxy Titanium Complexes for Controlling the Regiochemistry and Molecular Weight in 1-Olefin Polymerization

Cited by 19 publications

References 14 publications

Synthesis and structures of (R)-cyclopentadienyl-binaphthoxy titanium(iv) complexes and catalytic properties for olefin polymerization

Synthesis and structures of (R)-cyclopentadienyl-binaphthoxy titanium(iv) complexes and catalytic properties for olefin polymerization

Synthesis and Structural Diversity of Group 4 Metal Complexes with Multidentate Tethered Phenoxy-Amidine and Phenoxy-Amidinate Ligands

Post‐Metallocenes in the Industrial Production of Polyolefins

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