Polymer-bound titanium olefin isomerization catalysts

Bergbreiter, David E.; Parsons, Gregory L.

doi:10.1016/s0022-328x(00)89174-3

Cited by 22 publications

(3 citation statements)

References 11 publications

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“…In general, early-transition-metal allyl complexes have an enormous practical importance as either catalyst precursors or stoichiometric reagents in the synthesis of organic compounds. − For example, allyltitanium complexes are important intermediates in the Ziegler−Natta polymerization of conjugated dienes, , in the isomerization of olefins, , and in the stereoselective synthesis of homoallyl alcohols and their analogues . For early-transition-metal group 4 complexes containing the allyl moiety, in the majority of these compounds the metals exhibit the higher oxidation state: e.g., +4.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Catalytic Activities for the Polymerization of Olefins Promoted by Zirconium(III) and Titanium(III) Allyl Complexes

et al. 2001

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The reaction of early-transition-metal halides MCl 4 (M ) Zr, Ti) with 2 equiv of the lithium allyl compound ( t BuMe 2 SiCH) 2 CHLi‚TMEDA in toluene produced the corresponding reduced complexes [{( t BuMe 2 SiCH) 2 CH} 2 M(µ-Cl) 2 Li‚TMEDA] (M ) Zr (1), Ti (2)), that were isolated as air-sensitive dark brown (Zr) and brick red (Ti) crystals in 48% and 42% yield, respectively. In addition, each reaction is associated with the formation of the dimer of the allyl ligand (3). Complexes 1 and 2 and dimer 3 were fully characterized spectroscopically, including solid-state X-ray diffraction studies. Complex 1 represents the first solid-state characterization for a Zr(III)-allyl complex. Oxidation of complexes 1 and 2 allows the formation of the corresponding neutral complexes {( t BuMe 2 SiCH) 2 CH} 2 MCl 2 (M ) Zr (4), Ti 5)), which were isolated as air-sensitive light yellow (Zr) and orange (Ti) powders in 23% and 11% yields, respectively. The allylic moieties in complex 5 showed a dynamic interconverting coordination from η 3 to η 1 , causing an alternation between C 2 and C 2v symmetries of the complex. For the cationic complex 4 a similar dynamic interconverting coordination from η 3 to η 1 was observed. The catalytic activities of complexes 1 and 2 activated with MAO in the polymerization of propylene and ethylene were studied. The activity of complexes 1 and 2 was compared to the corresponding activities presented by complexes 4 and 5, respectively, indicating that during the polymerization process, Zr(III) and Ti(III) are oxidized to the corresponding cationic Zr(IV) and Ti(IV) species. For propylene, an elastomeric polypropylene was obtained, whereas for ethylene high-density polyethylene was produced. When the η 3 coordination modes of the ligands are operative in the complex, a cationic racemic octahedral compound is formed, which is responsible for the polymerization of the isotactic domains, whereas when the η 1 coordination modes of the ligands are effective, a cationic tetrahedral complex is obtained, accounting for the atactic domains. The formations of isotactic-atactic domains within a polymer chain give rise to elastomeric polypropylene.

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Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization, and Catalytic Activities for the Polymerization of Olefins Promoted by Zirconium(III) and Titanium(III) Allyl Complexes

et al. 2001

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“…Double bond isomerization has been exploited as a desired reaction in organic synthesis [5,6], SHOP technology [1], polymerization reactions [7], DuPont butadiene to adiponitrile synthesis [1], and asymmetric isomerization [8]. It has been reported that organotitanium [9] or titanocene [10,11] derivatives are useful catalysts for the selective isomerization of 1-alkenes to their corresponding 2-alkenes. The photochemical catalysis of 1-alkene isomerization reactions by Ru 3 (CO) 12 was also reported [12,13].…”

Section: Introductionmentioning

confidence: 99%

Allyl isomerization mediated by cyclopentadienyl ruthenium carbonyl compounds

Lin

et al. 2009

Transition Met Chem

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“…31 In general, allylic early-transition metal complexes are expected to have great practical applications either as catalyst precursors or stoichiometric reagents in the synthesis of organic compounds. [32][33][34][35][36][37][38][39][40] For example, allyltitanium complexes are important intermediates in the Ziegler-Natta polymerization of conjugated dienes, 41,42 in the isomerization of olefins, 43,44 in the stereoselective synthesis of homoallyl alcohols 45 and their analogues. 46 For early-transition group IV complexes, containing the allyl moiety, in most of the compounds the metals exhibit the higher oxidation state e.g., +4.…”

mentioning

confidence: 99%

Design of organometallic group iv heteroallylic complexes and their catalytic properties for polymerizations and olefin centered transformations

Smolensky¹,

Eisen²

2007

Dalton Trans.

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The use of metallocenes in many stoichiometric and catalytic processes has been the impetus for the development of new organometallic complexes, especially those containing early transition metals. The formation of coordinative unsaturated complexes using allylic, benzamidinate and aminopyridine families is presented. The synthesis and structural parameters of the new complexes, their activation and use in the polymerization of alpha-olefins and dienes, in the dehydrogenative coupling of silanes and in the hydroamination reactions comprise the objectives of this review.

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Polymer-bound titanium olefin isomerization catalysts

Cited by 22 publications

References 11 publications

Synthesis, Characterization, and Catalytic Activities for the Polymerization of Olefins Promoted by Zirconium(III) and Titanium(III) Allyl Complexes

Synthesis, Characterization, and Catalytic Activities for the Polymerization of Olefins Promoted by Zirconium(III) and Titanium(III) Allyl Complexes

Allyl isomerization mediated by cyclopentadienyl ruthenium carbonyl compounds

Design of organometallic group iv heteroallylic complexes and their catalytic properties for polymerizations and olefin centered transformations

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