Abstract: The present invention relates to compounds in which a transition metal is complexed by at least two ligand systems and at least two of the systems are reversibly joined to one another by at least one bridge comprising a donor and an acceptor, wherein at least one fluorenyl ligand is present and at least one substituent on the acceptor group is an alkyl or aryl radical. The invention further relates to the use of these compounds having a donor-acceptor interaction as polymerization catalysts for preparing high molecular weight elastomers.

Abstract: The present invention relates to a process for preparing homopolymers, copolymers and/or block copolymers of 1-olefins by living polymerization, to the use of the homopolymers, copolymers and/or block copolymers obtained for producing high-value materials and to the polymers formed from these homopolymers and/or block copolymers.

Abstract: The present invention relates to a process for preparing homopolymers, copolymers and/or block copolymers of 1-olefins by living polymerization, to the use of the homopolymers, copolymers and/or block copolymers obtained for producing high-value materials and to the polymers formed from these homopolymers and/or block copolymers.

Abstract: The present invention relates to compounds in which a transition metal is complexed by at least two ligand systems and at least two of the systems are reversibly joined to one another by at least one bridge comprising a donor and an acceptor, wherein at least one fluorenyl ligand is present and at least one substituent on the acceptor group is an alkyl or aryl radical. The invention further relates to the use of these compounds having a donor-acceptor interaction as polymerization catalysts for preparing high molecular weight elastomers.

Abstract: The present invention relates to compounds in which a transition metal is complexed with two ligand systems and the two systems are reversibly bonded together by at least one bridge consisting of a donor and an acceptor, at least one substituent on the acceptor group being a fluorinated aryl radical, to the use of these compounds as catalysts and to a process for the polymerization of olefins.

Abstract: The invention relates to a method for polymerizing polar substituted norbornenes and/or cycloalkenes, optionally, in the presence of another unsaturated compound. The method is characterized in that the polymerization is carried out in the presence of one or more tungsten carbine complexes and/or molybdenum carbine complexes.

Abstract: The present invention relates to compounds in which a transition metal is complexed with two ligand systems and the two systems are reversibly bonded together by at least one bridge consisting of a donor and an acceptor, at least one substituent on the acceptor group being a fluorinated aryl radical, to the use of these compounds as catalysts and to a process for the polymerization of olefins.

Abstract: The invention relates to novel &pgr;-complex compounds of transitional metals. The novel &pgr;-complex compounds are suitable for use as catalysts for the (co)polymerization of olefins, cyclo-olefins, alkynes, diolefins, vinyl ester and vinyl aromatics.

Abstract: &pgr;-complex compounds and in particular metallocene compounds of formula (Ia)(Ib), in which &pgr;I and &pgr;II represent &pgr;-systems, D designates a donor atom and A designates an acceptor atom, D and A being linked by a reversible coordinative bond such that the donor group assumes a positive (partial) charge and the acceptor group assumes a negative (partial) charge, at least one of D and A being part of the associated &pgr;-system in each case, M stands for a transition metal of the 3rd, 4th, 5th or 6th subgroup of the (Mendelian) periodic system of elements, X designates an anion equivalent and n designates the number zero, one, two three or four depending on the charges of M and those of &pgr;I and &pgr;II, are novel and can be used as catalysts for the (co)polymerization of olefins, i-olefins, alkines and/or diolefins or for ring-opening polyaddition.

Abstract: The present invention relates to compounds in which a transition metal is complexed with two ligand systems and the two systems are reversibly connected to one another by at least one bridge consisting of a donor and an acceptor. The resultant co-ordination bond between the donor atom and the acceptor atom produces a positive (partial) charge in the donor group and a negative (partial)charge in the acceptor group: The invention also relates to the use of these supported catalysts with a donor-acceptor interaction as polymerization catalysts.

Abstract: High-melting polyolefins can be prepared in bulk, in solution, in suspension or in the gas phase, the catalysts employed being metallocene compounds or &pgr; complex compounds of the formula in which CpI and CpII represent carbanions having a cyclopentadienyl-containing structure, &pgr;I and &pgr;II represent charged or electrically neutral &pgr; systems, D represents a donor atom and A represents an acceptor atom, where D and A are linked by a reversible coordinate bond such that the donor groups assumes a positive (part) charge and the acceptor group assumes a negative (part) charge, M represents a transition metal of sub-group III, IV, V or VI of the Periodic Table of the Elements (Mendeleev), including the lanthanides and the actinides, X denotes one anion equivalent and n denotes the number zero, one, two, three or four, depending on the charge of M.

Abstract: Metallocene compounds of the formula where CpI and CpII are carbanions having a cyclopentadienyl-containing structure, D is a donor atom and A is an acceptor atom, where D and A are linked by a reversible coordinative bond in such a way that the donor group takes on a positive (partial) charge and the acceptor group takes on a negative (partial) charge, M represents a transition metal of transition group III, IV, V or VI of the Periodic Table of the Elements (Mendeleev), X is one anion equivalent and n is, depending on the charge of M, zero, one, two, three or four, are new and can be used as catalysts for the (co)polymerization of olefins, i-olefins, alkines and/or diolefins or for ring-opening polyaddition. A typical X-ray structure analysis is represented by formula 18a.

Abstract: Thermoplastic elastomers can be prepared by (co)polymerization of monomers from the group consisting of C2-C8-&agr;-olefins, C4-C15-diolefins and other monomers in the bulk, solution, slurry or gas phase, the catalysts employed being metallocene compounds or the &pgr; complex compounds of the formulae in which CpI and CpII represent carbanions having a cyclopentadienyl-containing structure, &pgr;I and &pgr;II represent charged or electrically neutral &pgr; systems, D represents a donor atom and A represents an acceptor atom, where D and A are linked by a reversible coordinate bond such that the donor group assumes a positive (part) charge and the acceptor group assumes a negative (part) charge, M represents a transition metal of sub-group III, IV, V or VI of the Periodic Table of the Elements (Mendeleev), including the lanthanides and actinides, X denotes one anion equivalent and n denotes the number zero, one, two, three or four, depending on the charge of M.

Abstract: Elastomers can be prepared by (co)polymerization of monomers consisting of the group of C2-C8-&agr;-olefins, C4-C15-diolefins and other monomers in the bulk, solution, slurry or gas phase, the catalysts employed being metallocene compounds or the &pgr; complex compounds of the formula in which CpI and CpII represent carbanions having a cyclopentadienyl-containing structure, &pgr;I and &pgr;II represent charged or electrically neutral &pgr; systems, D represents a donor atom and A represents an acceptor atom, where D and A are linked by a reversible coordinate bond such that the donor group assumes a positive (part) charge and the acceptor group assumes a negative (part) charge, M represents a transition metal of sub-group III, IV, V or VI of the Periodic Table of the Elements (Mendeleev), including the lanthanides and the actinides, X denotes one anion equivalent and n denotes the number zero, one, two, three or four, depending on the charge of M.

Abstract: Cycloolefin copolymers for industrial applications, with the exception of the use for optical data memories, can be prepared by copolymerization of monomers from the group consisting of cyclic olefins, .alpha.-olefins having 2 or more C atoms and optionally conjugated or non-conjugated diolefins, the catalysts employed being metallocene compounds or .pi. complex compounds of the formula ##STR1## in which CpI and CpII represent carbanions having a cyclopenadienyl-containing structure,.pi.I and .pi.II represent charged or electrically neutral .pi.

Abstract: Compounds, for initiating the polymerization of ethylenically unsaturated compounds, having the formula ##STR1## where E is nitrogen, phosphorus, arsenic or antimony,X is oxygen, NR.sup.1 or sulphur,L is R.sup.8 R.sup.9 R.sup.10 E.sup.1 (Y).sub.n, alkyl ether, ester, alkyl and aryl nitrites, pyridine, piperidine, sulphoxides, sulphones, sulphimides, sulphodiimides or sulphur ylides, and R.sup.1 -R.sup.5 are as defined in the specification.

Abstract: A method for the polymerization of cycloolefins in a presence of a nickel (0) compound or a compound which can be converted in situ into a nickel (0) compound, as a catalyst. The catalyst of the present invention exhibits very high catalytic activity towards polymerization of cycloolefins.

Abstract: Heat-stable, flexible polarizers with a polarizing layer of a polymer with conjugated double bonds with the exception of exclusively polyacetylene-containing polymer matrixes are obtained if their surfaces are sealed with silicate.

Abstract: Thermostable, flexible polarizers having a polarizing layer of a polymer with conjugated double bondings are obtained when their surfaces are sealed by a protective layer of SiO.sub.x where x is from 1 to 2.

Abstract: The title compounds can be prepared by reaction of a styrene derivative with ethylene in the presence of a nickel catalyst which carries a phosphorus-oxygen chelate ligand, at a temperature of 20° to 160° C. and an ethylene pressure of 1 to 200 bar. Styrene derivatives extended with ethylene, of the formula in which R19 denotes hydrogen, C1-C4-alkyl, vinyl or chlorine and R38 denotes C1-C4-alkyl, C2-C4-alkenyl, C2-C7-acyl, flourine, chlorine or bromine and m assumes values of 4-104, with the exception of compounds wherein R19 denotes hydrogen and R38 denotes i-butyl or benzoyl, and m assumes the value 4, are new.