Cs-symmetric hafnocene complexes for synthesis of syndiotactic polypropene

Three new C s -symmetric ansa-hafnocene complexes such as dichloro[η 10-2,4-cyclopentadienyl-1-ylidenebis(4-methyldiphenyl-methylen)[2,7-bis(1,1-di-methylethyl)-9H-fluorene-9-ylidene]]hafnium ( 2) were synthesized which produce partiell syndiotactic polypropylenes with very high molecular weights. T...

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Bibliographic Details
Published in:Journal of organometallic chemistry 2003-11, Vol.684 (1), p.200-205
Main Authors: Kaminsky, Walter, Hopf, Andreas, Piel, Christian
Format: Article
Language:English
Subjects:
Hafnocene complexes
Metallocene catalysts
Propene polymerisation
Syndiotactic polypropylene
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Summary:Three new C s -symmetric ansa-hafnocene complexes such as dichloro[η 10-2,4-cyclopentadienyl-1-ylidenebis(4-methyldiphenyl-methylen)[2,7-bis(1,1-di-methylethyl)-9H-fluorene-9-ylidene]]hafnium ( 2) were synthesized which produce partiell syndiotactic polypropylenes with very high molecular weights. The influence of the methyl and methoxy substitution in the bridge was studied on the activity, tacticity, and molar mass. The hafnocene–MAO catalysts ( 1– 4) were active up to polymerisation temperatures of 90 °C and produces 55 000 kg polymer in 1 h by 1 mol of hafnocene. The molecular weight of the obtained elastic polypropylene reaches 2.2 million g mol −1. Three new C s -symmetric ansa-hafnocene complexes such as dichloro[η 10-2,4-cyclopentadienyl-1-ylidenebis(4-methyldiphenyl-methylen)[2,7-bis(1,1-di-methylethyl)-9H-fluorene-9-ylidene]]hafnium ( 2) were synthesized which produce partiell syndiotactic polypropylenes with very high molecular weights. The influence of the methyl and methoxy substitution in the bridge was studied on the activity, tacticity, and molar mass.
ISSN:0022-328X
1872-8561
DOI:10.1016/S0022-328X(03)00731-9