Effect of aryloxo substituents in ethylene polymerisation by tris(pyrazolyl)borate titanium(IV) complexes containing aryloxo ligands of type, TpTiCl2(OAr)

Nomura, Kotohiro; Hasumi, Shinya; Fujiki, Michiya; Itagaki, Koji

doi:10.1039/b910395c

Cited by 10 publications

(3 citation statements)

References 36 publications

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“…According to literature reports, with MAO as cocatalyst, the addition of a small amount of alkyl aluminium could normally enhance the catalytic activity of the corresponding system. 99,100 Therefore, the same strategy was adopted for ethylene polymerizations catalyzed by 8a-MMAO at 100 and 120 °C, as expected the addition of 100 equiv. of Al i Bu 3 slightly increased the activity from 1920 kg (mol-Ti h) −1 and 2082 kg (mol-Ti h) −1 to 2148 kg (mol-Ti h) −1 and 2202 kg (mol-Ti h) −1 , respectively (entry 15 vs. 35 and 16 vs. 36).…”

Section: Ethylene Polymerizationmentioning

confidence: 99%

High temperature ethylene polymerization catalyzed by titanium(iv) complexes with tetradentate aminophenolate ligands in cis-O, N, N chelating mode

et al. 2014

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A series of titanium trichloride complexes , ligated with claw-type tetradentate aminophenolate ligands were synthesized from the direct reaction of TiCl4(THF)2 with 1 equiv. of the corresponding aminophenol in the presence of triethylamine. For comparison purposes, titanium isopropoxide complexes were also synthesized via the reaction of Ti(O(i)Pr)4 and 1 equiv. of the proligand. Similar reactions of ZrCl4(THF)2 with the corresponding aminophenol ligands in the presence of triethylamine only allowed the isolation of zirconium complex . The X-ray diffraction studies reveal that titanium trichloride complexes , and titanium triisopropoxide complex all possess a distorted octahedral geometry with the tetradentate aminophenolate ligand in cis-O, N, N chelating mode, where the methoxy group of the aryl unit does not coordinate with the metal center in the solid state. Upon activation with MMAO, these titanium and zirconium(iv) complexes exhibited moderate to high catalytic activities for ethylene polymerization at 30-120 °C, producing high-molecular-weight polyethylenes with broad distributions (Mw/Mn = 10.2-34.8). The activities of titanium trichloride complexes are significantly higher than those of titanium isopropoxide and zirconium trichloride complexes at high temperatures. The highest activity of 15 456 kg (mol-Ti h)(-1) could be achieved by titanium trichloride complex with bromo groups on both ortho- and para-positions of the phenolate ring of the ligand at 120 °C.

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Section: Ethylene Polymerizationmentioning

confidence: 99%

High temperature ethylene polymerization catalyzed by titanium(iv) complexes with tetradentate aminophenolate ligands in cis-O, N, N chelating mode

et al. 2014

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“…] exhibits very high catalytic activity for ethene polymerization, in combination with MAO. 64 Tetrahedral mono(aryloxido) Ti IV complexes [Ti(O(o-R)Ar)X 3 ] (X = O i Pr, ArO = 2-tert-butyl-4-methylphenoxy; R = CMe 3 , CMe 2 Ph and CH 2 NMe 2 ) have been isolated. Attempts to synthesise the corresponding compound with R = CH 2 OMe, resulted in the unsymmetrical dimer [(2-tert-butyl-4-methyl-6-methoxymethylphenoxy)-TiCl(O i Pr)(m 2 -O i Pr) 2 TiCl(O i Pr) 2 ].…”

Section: Alkoxides Amides Etcmentioning

confidence: 99%

Titanium, zirconium, hafnium

Cotton¹

2010

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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“…are promising candidates, especially in terms of syntheses of new polymers by ethylene copolymerizations as demonstrated by using the aryloxo and the ketimide analogues. , Tris(pyrazolyl)borate group 4 metal complexes, Tp′MCl 3 [Tp′ = tris(pyrazolyl)borate; M = Ti, Zr, Hf], are known to exhibit high catalytic activities for ethylene polymerization in the presence of methylalumoxane (MAO), − and that the cationic species, generated in situ from Tp*Zr(CH 2 Ph) 3 [Tp* = HB(3,5-Me 2 -pyrazolyl) 3 ] or Tp Ms * Hf(CH 2 Ph) 3 [Tp Ms * = HB(3-mesitylpyrazolyl) 2 (5-mesitylpyrazolyl) − ] and [Ph 3 C][B(C 6 F 5 ) 4 ], polymerize ethylene . We also recently reported that Tp′TiCl 2 (OAr) [Tp = HB(pyrazolyl) 3 ; Ar = Ph, 2- i PrC 6 H 4 , 2,6-Me 2 C 6 H 3 , 2,6- i Pr 2 C 6 H 3 , 2,6-Ph 2 C 6 H 3 , C 6 F 5 ] exhibited moderate to remarkable catalytic activities for ethylene polymerization in the presence of MAO. , Moreover, the cationic complex, [Tp*TiMe(O-2,6-Me 2 C 6 H 3 )] + [MeB(C 6 F 5 ) 3 ] − ·2THF, polymerized ethylene affording polymer with unimodal distributions…”

Section: Introductionmentioning

confidence: 99%

Ethylene Polymerization by Phenoxy Substituted Tris(pyrazolyl)borate Ti(IV) Methyl Complexes

et al. 2011

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Ethylene polymerization using Tp*TiMe 2 (OAr) [Tp* = HB(3,5-Me 2 -pyrazolyl) 3 ; Ar) in the presence of Al alkyls have been explored. The catalytic activity by 2a,b-cocatalyst systems was highly affected by the Al/Ti molar ratios. Ethylene polymerizations by 2a,b-MAO catalyst systems proceeded in a quasi living manner between -30 and 25 °C, whereas certain degree of chain transfer was observed when the polymerizations by 2a,b were conducted in the presence of borate cocatalysts. The activity by the cationic Ti(IV)-methyl complex (3a) in the presence of Al(n-octyl) 3 was close to those by 2a-B(C 6 F 5 ) 3 -Al(n-octyl) 3 , Al i Bu 3 catalyst systems and the M n values in the resultant polymers were close with uniform distributions; the facts clearly indicate that the same catalytically active species play a role in this catalysis.

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Effect of aryloxo substituents in ethylene polymerisation by tris(pyrazolyl)borate titanium(IV) complexes containing aryloxo ligands of type, TpTiCl2(OAr)

Cited by 10 publications

References 36 publications

High temperature ethylene polymerization catalyzed by titanium(iv) complexes with tetradentate aminophenolate ligands in cis-O, N, N chelating mode

High temperature ethylene polymerization catalyzed by titanium(iv) complexes with tetradentate aminophenolate ligands in cis-O, N, N chelating mode

Titanium, zirconium, hafnium

Ethylene Polymerization by Phenoxy Substituted Tris(pyrazolyl)borate Ti(IV) Methyl Complexes

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