ansa-Zirconocene Polymerization Catalysts with Anelated Ring Ligands - Effects on Catalytic Activity and Polymer Chain Length

Stehling, Udo; Diebold, Josef; Kirsten, R.; Roell, W.; Brintzinger, Hans‐Herbert; Juengling, Stephan; Muelhaupt, Rolf; Langhauser, Franz

doi:10.1021/om00015a033

Cited by 352 publications

(257 citation statements)

References 0 publications

Supporting

Mentioning

228

Contrasting

Unclassified

Order By: Relevance

“…Only traces of unsaturated end-groups in the polymers were detected by 1 H NMR, which suggests that, in the used conditions, transfer to AlMe 3 (in equilibrium with MAO) was the dominant process. This is not unexpected, considering that, for metallocene catalysts with bridged rac-bis(1-indenyl) ligands, methyl substitution in positions 2,29 effectively inhibits chain transfer to the monomer 2,18) . iv) From an Arrhenius plot of the pk p P values (Fig.…”

Section: Ethene Polymerizationmentioning

confidence: 86%

Stopped-flow polymerizations of ethene and propene in the presence of the catalyst systemrac-Me2Si(2-methyl-4-phenyl-1-indenyl)2ZrCl2/methylaluminoxane

Busico

Cipullo²,

Esposito

1999

Macromol. Rapid Commun.

View full text Add to dashboard Cite

SUMMARY: The kinetics of ethene and propene polymerization at 20 -60 8C in the presence of the homogeneous catalyst system rac-Me 2 Si(2-methyl-4-phenyl-1-indenyl) 2 ZrCl 2 /methylaluminoxane was investigated by means of stopped-flow techniques. The specific rate of chain propagation, measured at the very short reaction times typical of this method, turned out to be L10 2 times higher for ethene than for propene; this suggests that diffusion limitations through the poly(ethylene) precipitating at longer reaction times may be responsible for the fact that the two monomers polymerize instead at comparable rates under "standard" conditions. It was also found that the concentration of active sites is significantly lower than the analytical Zr concentration.

show abstract

Section: Ethene Polymerizationmentioning

confidence: 86%

Stopped-flow polymerizations of ethene and propene in the presence of the catalyst systemrac-Me2Si(2-methyl-4-phenyl-1-indenyl)2ZrCl2/methylaluminoxane

Busico

Cipullo²,

Esposito

1999

Macromol. Rapid Commun.

View full text Add to dashboard Cite

show abstract

“…The method previously reported [12] was followed to prepare a mixture of the 1-H and 3-H isomers of the LiMBI, and its lithiated derivative was formed by reaction with LiBu and isolated as a pale yellow solid which can be stored for long time under an inert atmosphere.…”

Section: Resultsmentioning

confidence: 99%

Methylbenz[e]indenyl asymmetric ansa-metallocene and silylamido zirconium complexes

Sebastián

Royo

Gómez‐Sal

et al. 2003

Inorganica Chimica Acta

View full text Add to dashboard Cite

show abstract

“…Ellipsoid plot of compound 3 (50% probability level); hydrogen atoms have been omitted for clarity [12,26,31,32] The most remarkable difference is the orientation of the two nonequivalent benzyl ligands. One is located above the plane (torsion angle Cp MBI ϪZr(1)ϪC(1)ϪC(11) 62.6°) while the other is located below (torsion angle Cp MBI ϪZr(1)ϪC (2)ϪC (21) 158.1°), with respect to the C(1)ϪZr (1)ϪC (2) plane.…”

Section: Methodsmentioning

confidence: 99%

“…In this regard the 2-methylbenz[e]indenyl ligand (MBI) is an excellent choice for this purpose. The isolation of the first group 4 metallocenes containing this ligand has demonstrated high performance in ethylene and propylene polymerization [11,12] as well as in copolymerization processes using ethylene and octene [13] or ethylene/polar monomers such as 10-undecene-1-ol and allyl alcohol. [14,15] Metal alkyl compounds are convenient models not only for olefin polymerization but also for other insertion and transmetallation reactions and as carbonϪcarbon bond formation precursors.…”

Section: Introductionmentioning

confidence: 99%

Diastereoselective Insertion of Isocyanide into the Alkyl−Metal Bond of Methylbenz[e]indenyl ansa‐Zirconocene Complexes

et al. 2004

View full text Add to dashboard Cite

Alkylation of ansa‐zirconocene [Zr{(η5‐C5H5)SiMe2(MBI)}Cl2] (MBI = η5‐2‐Me−C13H7) with MgRCl gave the dimethyl complex [Zr{(η5‐C5H5)SiMe2(MBI)}Me2], but unresolvable mixtures containing mono‐alkylated compounds were obtained when bulkier alkyls were used. However pure dialkyl complexes [Zr{(η5‐C5H5)SiMe2(MBI)}R2] (R = CH2Ph, CH2SiMe3) were easily obtained using K(CH2Ph) and Li(CH2SiMe3) as alkylating agents. Diastereoselective insertion into the MBI‐unprotected Zr−R bond was observed when all of these dialkyl complexes were treated with 2,6‐xylyl isocyanide to give the iminoacyl compounds [Zr{(η5‐C5H5)SiMe2(MBI)}R{CR[η2‐N‐(2,6‐xylyl)]}] (R = Me, CH2Ph, CH2SiMe3). All of the new complexes were characterized by NMR spectroscopy and the X‐ray molecular structures of the dibenzyl and the imino‐benzyl compounds were determined. The catalytic activity for ethene polymerization and ethene/1‐hexene copolymerization of the dichloro zirconocenes [Zr{(η5‐C5H5)EMe2(MBI)}Cl2] (E = C, Si), activated with methylalumoxane (MAO), was measured. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

show abstract

ansa-Zirconocene Polymerization Catalysts with Anelated Ring Ligands - Effects on Catalytic Activity and Polymer Chain Length

Cited by 352 publications

References 0 publications

Stopped-flow polymerizations of ethene and propene in the presence of the catalyst systemrac-Me2Si(2-methyl-4-phenyl-1-indenyl)2ZrCl2/methylaluminoxane

Stopped-flow polymerizations of ethene and propene in the presence of the catalyst systemrac-Me2Si(2-methyl-4-phenyl-1-indenyl)2ZrCl2/methylaluminoxane

Methylbenz[e]indenyl asymmetric ansa-metallocene and silylamido zirconium complexes

Diastereoselective Insertion of Isocyanide into the Alkyl−Metal Bond of Methylbenz[e]indenyl ansa‐Zirconocene Complexes

Contact Info

Product

Resources

About