TY - JOUR
T1 - Semi-hydrogenated, asymmetric metallocene catalysts for the propylene polymerization
AU - Schloegl, Martin
AU - Troll, Carsten
AU - Thewalt, Ulf
AU - Rieger, Bernhard
N1 - Funding Information:
The authors thank DFG Deutsche Forschungs-gemeinschaft, SFB 569, for financial support of this research.
PY - 2003/6/1
Y1 - 2003/6/1
N2 - The hydrogenation of rac-[1-(9-η5-fluorenyl)-2-(5,6-cylopenta-2-methyl-1-η 5-indenyl)ethane]metallocene dichlorides (1a: Zr, 1b: Hf) with PtO2xH2O/H2 is reported. The diastereoselective formation of exclusively rac-[1-(2,3,4,5,6,7,8,9-octahydro-η5-fluorenyl)-2-(2-methyl- 1,4,4a(R;S),5,6,7,7a(S;R),8-octahydro-s-η5-indacenyl)ethane] metallocene dichlorides (2a: Zr, 2b: Hf) was shown by 1H-NMR and by X-ray analysis of 2a. Both compounds were activated in situ with triisobutylaluminum/PhC3+[B(C6F 5)4]- and tested as catalysts in propylene polymerization reactions. Comparison to the non-hydrogenated complexes revealed a decrease in molecular weight of the polymer and in catalyst activity. Experiments at elevated temperatures resulted in a lower stereospecificity and reduced isotacticity values indicating a polymerization mechanism analogous to C2-symmetric catalysts.
AB - The hydrogenation of rac-[1-(9-η5-fluorenyl)-2-(5,6-cylopenta-2-methyl-1-η 5-indenyl)ethane]metallocene dichlorides (1a: Zr, 1b: Hf) with PtO2xH2O/H2 is reported. The diastereoselective formation of exclusively rac-[1-(2,3,4,5,6,7,8,9-octahydro-η5-fluorenyl)-2-(2-methyl- 1,4,4a(R;S),5,6,7,7a(S;R),8-octahydro-s-η5-indacenyl)ethane] metallocene dichlorides (2a: Zr, 2b: Hf) was shown by 1H-NMR and by X-ray analysis of 2a. Both compounds were activated in situ with triisobutylaluminum/PhC3+[B(C6F 5)4]- and tested as catalysts in propylene polymerization reactions. Comparison to the non-hydrogenated complexes revealed a decrease in molecular weight of the polymer and in catalyst activity. Experiments at elevated temperatures resulted in a lower stereospecificity and reduced isotacticity values indicating a polymerization mechanism analogous to C2-symmetric catalysts.
KW - Diastereoselective Hydrogenation
KW - Metallocene Polymerization Catalyst
KW - Polypropylene
UR - http://www.scopus.com/inward/record.url?scp=0041743114&partnerID=8YFLogxK
U2 - 10.1515/znb-2003-0608
DO - 10.1515/znb-2003-0608
M3 - Article
AN - SCOPUS:0041743114
SN - 0932-0776
VL - 58
SP - 533
EP - 538
JO - Zeitschrift fur Naturforschung - Section B Journal of Chemical Sciences
JF - Zeitschrift fur Naturforschung - Section B Journal of Chemical Sciences
IS - 6
ER -