Novel 2-indenyl ansa-zirconocenes for the polymerization of α-olefins

Herzog, Matthew Nathaniel; Chien, James C. W.; Rausch, Marvin D.

doi:10.1016/s0022-328x(02)01333-5

Cited by 18 publications

(3 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One major challenge in polymerization catalysis of olefins is the precision control of polymer microstructures, which allows the designing of material properties . In recent times, tailor-made C 1 -symmetric metallocene catalysts gave access to polymers of varying microstructures depending on the nature of the active metal center and on the particular ligand substitution. − In 1999, we presented a new family of highly active zirconocene dichlorides that allowed the programming of single stereoerrors along an isotactic chain, depending on the monomer concentration . These asymmetric “dual-side” catalysts (e.g., 6a , b , Scheme ) possess alkyl or alkoxy substituents in the 5,6-position of the indenyl moieties that suppress chain-end epimerization reactions − and lead to improved activities and to ultrahigh molecular weights .…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Metallocene Catalysts Based on Dibenzothiophene: A New Approach to High Molecular Weight Polypropylene Plastomers

et al. 2003

View full text Add to dashboard Cite

Synthesis and polymerization data of a series of new sulfur-containing C 1 -symmetric metallocenes,rac-[1-(9-η 5 -fluorenyl)-2- (8), are reported. The characteristic structural feature of these complexes is the 2-methyl-1H-benzo[b]indeno[4,5-d]thiophene moiety (3: MBIT), which was derived from dibenzothiophene. In the case of 7a-c the MBIT unit shows a "back" orientation, whereas in 8 it is directed to the "front" of the tetrahedral metallocene dichloride species, which was unambiguously illustrated by X-ray structure analysis. Propylene polymerization experiments revealed higher activity and stereoselectivity for 7a/MAO compared to 8/MAO. The catalysts 7a,8/MAO were found to operate under different polymerization mechanisms indicated by a diverse correlation of tacticity and polymerization temperature. Crystalline, flexible polypropylenes with tacticities ranging from 65 e [mmmm] e 90 and molecular weights up to 2 × 10 5 g mol -1 were obtained for 7a/MAO, whereas experiments using 8/MAO produced low tacticity, waxy materials. To achieve ultrahigh molecular weight isotactic polypropylene plastomers (M w up to 1.5 × 10 6 g mol -1 ), further investigations on the hafnium dimethyl complex 7c/[(C 6 H 5 ) 3 C + ][(C 6 F 5 ) 4 B -] in liquid propylene were performed.

show abstract

Section: Introductionmentioning

confidence: 99%

Asymmetric Metallocene Catalysts Based on Dibenzothiophene: A New Approach to High Molecular Weight Polypropylene Plastomers

et al. 2003

View full text Add to dashboard Cite

show abstract

“…Indanones and related compounds are important bioactive molecules. These compounds have exhibited biological activity against cancer cells and Alzheimer’s disease; moreover they can be used as synthetic intermediates for several drugs and as precursors to natural products [3,4,5,6,7,8,9,10]. Other applications include their use as ligands in olefinic polymerization catalysts [11,12,13,14,15,16,17,18,19,20] and as discotic liquid crystals [21].…”

Section: Introductionmentioning

confidence: 99%

Non-Conventional Methodologies in the Synthesis of 1-Indanones

et al. 2014

View full text Add to dashboard Cite

show abstract

“…15 After that, Matthew et al reported that 2-substituted indenyl zirconocenes were active for ethylene homopolymerization. 16 However, little information was available on the ethylene or ethylene/1-hexene copolymerization with the bridged (cyclopentadienyl) (indenyl) metallocenes. In this paper, we will report the synthesis and α-olefin (co)polymerization of five new substituted Cp-Ind complexes, 3-7 (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

α‐olefin homopolymerization and ethylene/1‐hexene copolymerization catalysed by novel ansa‐group IV complexes/MAO system

Yang

Zhang

Huang

2007

Applied Organom Chemis

View full text Add to dashboard Cite

The catalytic properties of a set of ansa-complexes (R-Ph) 2 C(Cp)(Ind)MCl 2 [R = t Bu, M = Ti (3), Zr (4) or Hf (5); R = MeO, M = Zr (6), Hf (7)] in α-olefin homopolymerization and ethylene/1-hexene copolymerization were explored in the presence of MAO (methylaluminoxane). Complex 4 with steric bulk t Bu group on phenyl exhibited remarkable catalytic activity for ethylene polymerization. It was 1.6-fold more active than complex 11 [Ph 2 C(Cp)(Ind)ZrCl 2 ] at 11 atm ethylene pressure and was 4.8-fold more active at 1 atm pressure. The introduction of bulk substituent t Bu into phenyl groups not only increased the catalytic activity greatly but also enhanced the content of 1-hexene in ethylene/1-hexene copolymerization. The highest 1-hexene incorporation was 25.4%. In addition, 4 was also active for propylene and 1-hexene homopolymerization, respectively, and low isotactic polypropylene (mmmm = 11.3%) and isotactic polyhexene (mmmm = 31.6%) were obtained.

show abstract

Novel 2-indenyl ansa-zirconocenes for the polymerization of α-olefins

Cited by 18 publications

References 17 publications

Asymmetric Metallocene Catalysts Based on Dibenzothiophene: A New Approach to High Molecular Weight Polypropylene Plastomers

Asymmetric Metallocene Catalysts Based on Dibenzothiophene: A New Approach to High Molecular Weight Polypropylene Plastomers

Non-Conventional Methodologies in the Synthesis of 1-Indanones

α‐olefin homopolymerization and ethylene/1‐hexene copolymerization catalysed by novel ansa‐group IV complexes/MAO system

Contact Info

Product

Resources

About