Frank Küber’s research while affiliated with Hospital Frankfurt Hoechst and other places

What is this page?


This page lists works of an author who doesn't have a ResearchGate profile or hasn't added the works to their profile yet. It is automatically generated from public (personal) data to further our legitimate goal of comprehensive and accurate scientific recordkeeping. If you are this author and want this page removed, please let us know.

Publications (9)


ChemInform Abstract: Metallocenes - Special Tools for the Preparation of Polyolefins
  • Article

February 2010

·

3 Reads

ChemInform

M. AULBACH

·

F. KUEBER

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.



Metallocene - ma�geschneiderte Werkzeuge zur Herstellung von Polyolefinen

October 2004

·

38 Reads

·

39 Citations

Chemie in unserer Zeit

geb. 1962 in Bad Homburg. 1983 bis 1987 Chemiestudium an der Universität Frankfurt. Diplomarbeit 1988 bei der Hoechst AG/Frankfut am Main. promotion 1991 bei g. Quinkert mit einer Arbeit über die computergestützte Konformationsanalyse bei der Synthese von makrocyclischen Naturstoffen. Promotions- und Studiensbschluß-Stipendium des Fonds der Chemischen industrie. 1991 Eintriet in die Hoechst AG, seit 1994 Projektleiter „Metallocensynthese” in der Zentralforschung der Hoechst AG.


New bridged zirconocenes for olefin polymerization: Binuclear and hybrid structures

February 1998

·

6 Reads

·

5 Citations

Journal of Molecular Catalysis A Chemical

Four newly synthesized bridged bisindenyl zirconocenes which are derivatives of known structures have been tested in polymerizations of liquid propylene with methylaluminoxane as cocatalyst. They include two asymmetric and two binuclear systems which are suitable for isotactic polymerization. Surprising differences from the behavior of similar systems (regiospecificity, chain termination) are found and discussed.


New bridged zirconocenes for olefin polymerization: Binuclear and hybrid structures 1 Dedicated to Professor Dr. Gottfried Huttner on the occasion of his 60th birthday. 1

February 1998

·

4 Reads

·

54 Citations

Journal of Molecular Catalysis A Chemical

Four newly synthesized bridged bisindenyl zirconocenes which are derivatives of known structures have been tested in polymerizations of liquid propylene with methylaluminoxane as cocatalyst. They include two asymmetric and two binuclear systems which are suitable for isotactic polymerization. Surprising differences from the behavior of similar systems (regiospecificity, chain termination) are found and discussed.


Tin-bridged ansa-metallocenes of zirconium: Synthesis and catalytic performance in olefin polymerization

February 1996

·

4 Reads

·

39 Citations

Journal of Organometallic Chemistry

The first tin-bridged zirconocenes [(CH3)2Sn(C5H4)2]Zr[N(CH3)2]2 (3) and Sn{(C5H4)2Zr[N(CH3)2]2}2 (4) have been obtained from tetrakis(dimethylamido)zirconium (1) and the CH-acidic ligands (CH3)2Sn(C5H5)2 (2a) and Sn(C5H5)4 (2b), respectivily. The ansa-zirconocene 3 is formed in quantitative yield, 4 in 81% yield. The bi- and trimetallic complexes 3 (ZrSn) and 4 (Zr2 Sn) polymerize ethylene more efficiently than the well-known silicon-bridged analogue of 3 (Si instead of Sn).


Stereospecific metallocene catalysts: Scope and limits of rational catalyst design

January 1995

·

10 Reads

·

44 Citations

Macromolecular Symposia

Structure-performance relationships in the propene polymerization behaviour of a number of silicon bridged bisindenyl zirconocenes show a rational pattern. Prognosis of the polymerization behaviour of different type structures, however, often fails, which is demonstrated by three examples of new zirconocenes. These include two bisindenyl complexes with two-membered silicon bridges and one isospecific bridged fluorenyl cyclopentadienyl species. It is thus demonstrated that the scope of a “rational catalyst design” in the field of metallocene catalysts is still limited.


New Isotactic Polypropylenes via Metallocene Catalysts

January 1995

·

10 Reads

·

41 Citations

Chiral bridged bisindenyl zirconoeenes with special substitution patterns on the aromatic rings are potentially commercial catalysts for the production of isotactic polypropylenes. The performance characteristics of these systems are different, the variations being induced by size and position of the substituents. The novel catalysts will be used for the production of new iPP grades with enhanced properties or unprecedented property combinations. Typical features of metailocene iPP polymers are higher stiffness, higher transparency, and a lower level of extractables than conventional products. The most recent new designs of metailocene PP catalysts are discussed. These include asymmetric systems and metallocenes inducing two-step-polymerization mechanisms.


The Influence of Aromatic Substituents on the Polymerization Behavior of Bridged Zirconocene Catalysts

March 1994

·

15 Reads

·

614 Citations

Organometallics

The synthesis of seven new bridged zirconocenes is described, which make isotactic polypropylene when used in polymerizations of propylene with methylaluminoxane as cocatalyst. Their polymerization behavior in propylene and ethylene polymerizations is examined and discussed. Aromatic substituents in appropriate positions of the zirconocene ligand frame result in catalysts with activities, stereospecificities, and polypropylene molecular weights much higher than those of any previously described metallocene system. By structure variations it is demonstrated that the effectiveness of these substitutions strongly depends on their position and on a nonincremental synergism with alkyl substituents on the ligand frame. The high activities of the systems can be explained well by electronic effects, whereas steric effects obviously play the more important role for the high stereospecificities and high molecular weights of the polymers.

Citations (4)


... The interest in this area has primarily been driven by the potential to exploit intermetallic cooperativity/synergism between the two or more proximal metal centers to eventually enhance the performance of polymerization systems. For instance, several studies on dinuclear catalysts suggest that catalyst activity [3][4][5][6][7][8][9][10][11][12][13] and molecular weight, [3,7,10,14] tacticity, [13][14][15], or comonomer incorporation [8,[16][17][18][19][20] of/in the resulting polymers the existence of pairs of diastereoisomers in each case, and also of their different tautomers (i.e., isomers of C=C bonds within the CpH rings). The ESI-MS measurements data showed clearly the expected molecular [M + H] + ions at m/z 815.55, 787.52 for 2a,b and at 853.51 ([M + K] + ) for 2c. ...

Reference:

Synthesis, APPI Mass-Spectrometric Characterization, and Polymerization Studies of Group 4 Dinuclear Bis(ansa-metallocene) Complexes
New bridged zirconocenes for olefin polymerization: Binuclear and hybrid structures 1 Dedicated to Professor Dr. Gottfried Huttner on the occasion of his 60th birthday. 1
  • Citing Article
  • February 1998

Journal of Molecular Catalysis A Chemical

... Comparing different metallocene catalysts, zirconocene catalysts are more active than titanocene and the classical Ziegler-Natta catalysts by around 10-100 times. 16,17 Moreover, titanocene catalysts cannot be used at high temperature and for long polymerization times, because the titanium(IV) will be then reduced to the inactive titanium(III). 18 In addition, hafnocene catalysts are about 10 times less active than titanocene catalysts, but they do produce polyethylene with a higher molecular weight. ...

Stereospecific metallocene catalysts: Scope and limits of rational catalyst design
  • Citing Article
  • January 1995

Macromolecular Symposia

... The interest in this area has primarily been driven by the potential to exploit intermetallic cooperativity/synergism between the two or more proximal metal centers to eventually enhance the performance of polymerization systems. For instance, several studies on dinuclear catalysts suggest that catalyst activity [3][4][5][6][7][8][9][10][11][12][13] and molecular weight, [3,7,10,14] tacticity, [13][14][15], or comonomer incorporation [8,[16][17][18][19][20] of/in the resulting polymers Catalysts 2018, 8, x FOR PEER REVIEW 3 of 19 Scheme 2. Synthesis of the para-and meta-phenylene-bridged bis(fulvenes) 1a-c. ...

New bridged zirconocenes for olefin polymerization: Binuclear and hybrid structures
  • Citing Article
  • February 1998

Journal of Molecular Catalysis A Chemical