Abstract: The present invention relates to a transition metal half metallocene catalyst with a noble structure for preparing syndiotatic styrene polymer having high activity, superior stereoregularity, high melting point and broad molecular weight distribution and a process for preparing styrene polymer using the same. The present invention provides a half metallocene catalyst having a single nucleus structure, in which a transition metal in Groups 3 to 10 on the periodic table is connected to a cycloalkanedienyl group or its derivative forming 5-coordinate bond on a side thereof and to any one of triethanolamine, N-alkyldiethanolamine and N-dialkylethanolamine group, all of which have a plurality of binding sites and high steric hinderance, on the other side thereof. The noble metallocene catalyst according to the present invention is useful for preparing highly syndiotatic vinyl aromatic polymer with broad molecular weight distribution and high activity.

Abstract: Disclosed is a multinuclear transition metal half metallocene catalyst having a multinuclear half metallocene structure in which a transition metal of groups 3 to 10 on periodic table is connected to a cycloalkandienyl group or its derivative group on a side and also connected to phenol or phenolamine compound having a plurality of binding sites on another side. The metallocene catalyst is useful to produce syndiotatic styrene polymer having superior steroreguality, high melting point and broad molecular weight distribution with high activity together with a small amount of a cocatalyst. Further disclosed is a method for preparing styrene polymers using the same catalyst.

Abstract: The invention is a Group IVB transition metal compound which may be employed in the polymerization of olefins to produce high molecular weight polymers.

Abstract: The invention discloses a method for making a hydrogenated metallocene catalyst component comprising the steps of: 1. Providing a compound comprising at least one aromatic group; 2. Hydrogenating the at least one aromatic group in the presence of hydrogen and a hydrogenation catalyst to form a hydrogenated compound; and 3. Forming a metallocene catalyst component from the hydrogenated compound from step 2.

Abstract: A borohydride metallocene complex of a lanthanide, its process of preparation, a catalytic system incorporating a borohydride metallocene complex and a process for the copolymerization of olefins employing this catalytic system.

Abstract: A bridged metallocene compound of formula (I) wherein: M is an atom of a transition metal selected from those belonging to group 3, 4, or to the lanthanide or actinide groups in the Periodic Table of the Elements; X, equal to or different from each other, is a hydrogen atom, a halogen atom, a R, OR, OSO2CF3, OCOR, SR, NR2 or PR2 group; L is a divalent bridging group; R1 and R2, equal to each other, are C1-C40 hydrocarbon radical; R3 is hydrogen or a are C1-C40 hydrocarbon radical and W is an aromatic 5 or 6 membered ring.

Abstract: This invention relates to organometallic precursor compounds represented by the formula (Cp(R?)x)yM(H)z-y, a process for producing the organometallic precursor compounds, and a method for depositing a metal and/or metal carbide layer, e.g., Ta metal and/or TaC layer, on a substrate by the thermal or plasma enhanced disassociation of the organometallic precursor compounds, e.g., by CVD or ALD techniques. The metal and/or metal carbide layer is useful as a liner or barrier layer for conducting metals and high dielectric constant materials in integrated circuit manufacturing.

Abstract: A method for making siloxy-bridged ligand precursors and metallocene complexes is disclosed. Indanone enolates react with cyclopentadienylsilyl compounds to produce ligand precursors, which are reacted with a Group 3-10 transition metal source to generate metallocene complexes. The method provides simple, regioselective access to particular siloxy-bridged metallocenes starting from easily elaborated indanones.

Abstract: This invention relates to organometallic precursor compounds represented by the formula (Cp(R?)x)yM(H)z-y, a process for producing the organometallic precursor compounds, and a method for depositing a metal and/or metal carbide layer, e.g., Ta metal and/or TaC layer, on a substrate by the thermal or plasma enhanced disassociation of the organometallic precursor compounds, e.g., by CVD or ALD techniques. The metal and/or metal carbide layer is useful as a liner or barrier layer for conducting metals and high dielectric constant materials in integrated circuit manufacturing.

Abstract: This invention provides a new method of forming a self-assembling monolayer (SAM) of alcohol-terminated or thiol-terminated organic molecules (e.g. ferrocenes, porphyrins, etc.) on a silicon or other group IV element surface. The assembly is based on the formation of an E-O— or an E-S— bond where E is the group IV element (e.g. Si, Ge, etc.). The procedure has been successfully used on both P- and n-type group IV element surfaces. The assemblies are stable under ambient conditions and can be exposed to repeated electrochemical cycling.

Abstract: A process for producing a cycloolefin addition polymer comprising addition-polymerizing a cycloolefin in the presence of a catalyst comprising a combination of a specific transition metal compound of Group 4 of the Periodic Table, with an organoaluminum oxy compound, and/or a compound capable of reacting with the Group 4 transition metal compound to form an ion pair. The specific group 4 transition metal compound preferably has a structure such that the group 4 transition metal is bonded to a cyclopentadienyl ring in an ?1 mode. The above-mentioned catalyst exhibits high activity for both of addition homopolymerization of a cycloolefin and addition copolymerization of a cycloolefin with an ?-olefin.

Abstract: Non-fluorinated copper precursors and methods for making and using same are described herein. In certain embodiments, the copper precursors described herein may be used as precursors to deposit copper films and alloys thereof on a substrate through, for example, atomic layer deposition or chemical vapor deposition conditions.

Abstract: Disclosed is a novel transition metal compound which is used for forming a metallocene catalyst for olefin polymerization. Specifically disclosed is a novel transition metal compound represented by the general formula below which enables to form a metallocene catalyst that has a balanced reactivity with ethylene and a comonomer selected from ?-olefins having 3-20 carbon atoms and enables to produce an ?-olefin polymer having a high molecular weight. Also specifically disclosed are a catalyst for olefin polymerization containing such a transition metal compound, and a method for producing a propylene/ethylene-?-olefin block copolymer wherein such a catalyst is used.

Abstract: A bridged metallocene compound of formula (I) wherein: M is an atom of a transition metal; X, is a hydrogen atom, a halogen atom, or a hydrocarbon-based group; R1 is a C1-C40 hydrocarbon radical; R2 and R3, form together a condensed 3-7 membered ring; R4 is a hydrogen atom or a C1-C40 hydrocarbon radical; W is an aromatic 5 or 6 membered ring.

Abstract: Process for preparing halide metallocene compounds comprising the step of reacting the dialkyl derivative with a halogenating agent of formula R3xTLw wherein: L is chlorine, iodine or bromine; R3 is hydrogen or a hydrocarbon group; T is a metal of groups 2-14 of the periodic table of the elements; and x is ?1 so that x+w is equal to the oxidation state of the metal T.

Abstract: The present invention is directed to a method of making a ligand which can be used to form an ansa-metallocene. Further, the present invention is directed to a method of making the ansa-metallocene. In both methods the process steps employed to form the ligand are conducted in the presence of tetrahydrofuran, a substituted tetrahydrofuran, tetrahydropyran, a substituted tetrahydropyran or ethylene glycol dimethyl ether.

Abstract: Methods and compositions for depositing metal films are disclosed herein. In general, the disclosed methods utilize precursor compounds comprising gold, silver, or copper. More specifically, the disclosed precursor compounds utilize pentadienyl ligands coupled to a metal to increase thermal stability. Furthermore, methods of depositing copper, gold, or silver are disclosed in conjunction with use of other precursors to deposit metal films. The methods and compositions may be used in a variety of deposition processes.

Abstract: The present invention provides a process for producing an alkoxy-titanium complex of formula (2) by reacting a titanium halide complex of formula (1) with an alkaline earth metal alkoxide: wherein A denotes a Group 14 element in a periodic table; R1, R2, R3, and R4 are the same or different and denote a hydrogen atom, halogen, a C1-20 alkyl group which may be substituted by halogen, a C6-20 aryl group which may be substituted by halogen, or the like; R5, R6, R7, R8, R9, and R10 are the same or different and independently denote a hydrogen atom, halogen, a C1-20 alkyl group which may be substituted by halogen, or the like; and X1 and X2 independently denote any halogen atom: wherein R11 and R12 are the same or different and independently denote a C1-20 alkyl group which may be substituted by halogen, or the like.

Abstract: A process for preparing 1-butene polymers, comprising polymerizing 1-butene or copolymerizing 1-butene with ethylene, propylene or an alpha-olefin of formula CHT2=CHT wherein T is a C3-C10 alkyl group, in the presence of a catalyst system obtainable by contacting: A) a metallocene compound belonging to formula (I): wherein M is zirconium titanium or hafnium; X, equal to or different from each other, is a hydrogen atom, a halogen atom, a hydrocarbon radical optionally containing heteroatoms; R4, R5, R6, R7, R8, R9, R10, R11, R12 and R13 are hydrogen atoms, or C1-C4O hydrocarbon radicals optionally containing heteroatoms; R1, R2 and R3, are linear or branched, C1-C2o-alkyl radicals, optionally containing heteroatoms: B) a Jumoxane or a compound capable of forming an alkyl metallocene cation; and optionally C) organo aluminum compound.

Abstract: Disclosed is a homogeneous catalyst system for producing an ethylene homopolymer or an ethylene copolymer with ?-olefin. Specifically, this invention pertains to a transition metal catalyst which has stability under high temperature solution polymerization at 120˜250° C., in which a cyclopentadiene derivative and an electron donating substituent, both of which are bonded to a Group IV transition metal acting as a central metal, are crosslinked through a silyl derivative substituted with a cyclohexyl, to a catalyst system including such a transition metal catalyst and an aluminoxane cocatalyst or a boron compound cocatalyst, and to a method of producing an ethylene homopolymer or an ethylene copolymer with ?-olefin, having high molecular weight, using the catalyst system under conditions of high-temperature solution polymerization.

Abstract: The bridged metallocene compound or the olefin polymerization catalyst which comprises the compound, enables high polymerization activity in polymerizing one or more monomers selected from ethylene and ?-olefins. The bridged metallocene compound contains specific substituted cyclopentadienyl and fluorenyl groups which are linked via carbon or silicon atoms. In the method for the preparation of polyolefins, one or more monomers, preferably ethylene as an essential monomer, selected from ethylene and ?-olefins are copolymerized in the presence of the olefin polymerization catalyst comprising the bridged metallocene compound, so that an ethylene based polymer with an ethylene content of more than 50 mol % is obtained.

Abstract: Tantalum precursors suitable for chemical vapor deposition of tantalum-containing material, e.g., tantalum, TaN, TaSiN, etc., on substrates. The tantalum precursors are substituted cyclopentadienyl tantalum compounds. In one aspect of the invention, such compounds are silylated to constitute tantalum/silicon source reagents. The precursors of the invention are advantageously employed in semiconductor manufacturing applications to form diffusion barriers in connection with copper metallization of the semiconductor device structure.

Abstract: A metallocene complex is represented by the the formula (CpR5)nMXk where Cp (each occurrence) is a cyclopentadienyl group; each of the five R substituents on the or each cyclopentadienyl group is independently selected from hydrogen, C1 to C30 substituted or unsubstituted hydrocarbyl, halohydrocarbyl, silylhydrocarbyl or silylhalohydrocarbyl, wherein two adjacent R substituents may be joined to form part of a saturated, partially unsaturated or aromatic monocyclic or polycyclic ring structure, and SiR?2NR?2 where each of the two R? substituents is independently selected from hydrogen, C1 to C30 substituted or unsubstituted hydrocarbyl, halohydrocarbyl, silylhydrocarbyl or silylhalohydrocarbyl, wherein two adjacent R? substituents may be joined to form part of a saturated, partially unsaturated or aromatic monocyclic or polycyclic ring structure, and each of the two R? substituents is independently selected from C2 to C30 substituted or unsubstituted hydrocarbyl, halohydrocarbyl, silylhydrocarbyl or silylhal

Abstract: The present invention refers to a metallocene catalyst component for producing polyolefins according to formula (I) R?s (CpRn)g (CpRn) M Q3-g (I) or according to formula (II) R?(CpRn)MeXQ (II) wherein—each Cp is a substituted or unsubstituted cyclopentadienyl ring with the bridge-head position of at least one of the cyclopentadienyl rings being occupied by a silicon atom;—each R is the same or different and is hydrogen or a hydrocarbyl radical such as alkyl, alkenyl, aryl, alkylaryl or arylalkyl radical containing from 1 to 20 carbon atoms or two carbon atoms are joined together to form a C4-C6 ring; —R? is a structural bridge between two Cp rings;—M is a group IIIB, IVB, VB or VIB metal;—Q is a hydrocarbyl radical such as aryl, alkyl, alkenyl, alkylaryl or arylalkyl radical having from 1 to 20 carbon atoms, a hydrocarboxy radical having from 1 to 20 carbon atoms or a halogen and can be the same or different from each other;—s is 0 or 1, g is 0, 1 or 2 and s is 0 when g is 0, n is 4 when s is 1 and n is 5 whe

Abstract: A metallocene compound represented by the following Chemical Formula 1: wherein M is a transition metal of Group 4; Cp denotes a cyclopentadienyl ring unsubstituted or substituted by hydrogen, alkyl, cycloalkyl, aryl, alkenyl, alkylaryl, arylalkyl or arylalkenyl radicals; Qs, which are the same or different, are halogen radicals, alkyl, alkenyl, aryl, alkylaryl, or arylakyl radicals having 1 to 20 carbon atoms, or alkylidene radicals having 1 to 20 carbon atoms; A? is methoxymethyl, t-butoxymethyl, tetrahydropyranyl, tetrahydrofuranyl, 1-ethoxyethyl, 1-methyl-1-methoxyethyl, or t-butyl; and a is an integer of 4 to 8. The metallocene compounds in this invention can be strongly supported on the inorganic support, and the supported catalyst of this invention allows for an olefin polymerization process without any fouling in the reactor, and produces a polymer with better morphology and bulk density.

Abstract: A metallocene compound of formula (I): wherein M is zirconium, titanium and hafnium; X is a hydrogen atom, a halogen atom or a hydrocarbon radical; R1 is a linear C1-C20-alkyl radical; R2 is a hydrogen atom or hydrocarbon R3, R4, R5, R6, R7, and R8, are hydrogen atoms or hydrocarbon radicals, A is a sulphur (S) atom or an oxygen (O) atom; Q is a radical of formula (II), (III) or (IV) being bonded to the indenyl at the position indicated by the symbol *; (II), (III), (IV) wherein T1 is a sulphur atom, an oxygen (O) atom or a NR; R9, R10 and R11 are hydrogen atoms or hydrocarbon radicals; T2, T3, T4, T5, and T6 are carbon atoms (C) or nitrogen atoms (N); m1, m2, m3, m4 and m5 are 0 or 1; R12, R13, R14, R15 and R16 are hydrogen atoms or hydrocarbon radicals with the provisos that at least one of R12, R13, R14, R15 and R16 is different from hydrogen atoms, and that no more than two of T2, T3, T4, T5 and T6 are nitrogen atoms.

Abstract: The present invention discloses a metallocene catalyst component of formula (Flu-R?-Cp)M(?3-C3R?5)(ether)n (I) wherein Cp is a cyclopentadienyl, substituted or unsubstituted, Flu is a fluorenyl, substituted or unsubstitutted, R? is a structural bridge between Cp and Flu imparting stereorigidity to the component, M is a metal Group III of the Periodic Table, each R? is the same or different and is hydrogen or a hydrocarbyl having from 1 to 20 carbon atoms and n is 0, 1 or 2. It further discloses a process for preparing said catalyst component and its used in the controlled polymerisation of polar or non polar monomers.

Abstract: A new class of heterocyclic metallocenes, a catalytic system containing them and a process for polymerizing addition polymerizable monomers using said catalytic system are disclosed; the heterocyclic metallocenes correspond to the formula (I): YjR?iZjjMeQkPl wherein Y is a coordinating group containing a six ? electron central radical directly coordinating Me, to which are associated one or more radicals containing at least one non-carbon atom selected from B, N, O, Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb and Te; R? is a divalent bridge between the Y and Z groups; Z is a coordinating group, optionally being equal to Y; Me is a transition metal; Q is halogen or hydrocarbon substituents; P is a counterion; i is 0 or 1; j is 1–3; jj is 0–2; k is 1–3; and l is 0–2.

Abstract: A process for separating inorganic and organometallic by-products from a mixture comprising at least one organometallic transition metal compound as product and at least one organometallic by-product and at least one inorganic by-product as by-products comprises the steps A) admixing the mixture comprising the product, the organometallic by-product and the inorganic by-product with a mixture comprising at least one polar organic extractant and water and separating off the undissolved residue, B) washing the residue from step A) with a nonpolar organic extractant or a mixture comprising at least one nonpolar organic extractant and at least one aprotic polar organic solvent and C) drying the residue which has been washed in step B) and comprises the organometallic transition metal compound.

Abstract: Metal ketoiminate or diiminate complexes, containing copper, silver, gold, cobalt, ruthenium, rhodium, platinum, palladium, nickel, osmium, or indium, and methods for making and using same are described herein. In certain embodiments, the metal complexes described herein may be used as precursors to deposit metal and metal-containing films on a substrate through, for example, atomic layer deposition or chemical vapor deposition conditions.

Abstract: The invention relates to a process for preparing racemic metallocene biphenoxide complexes by reacting bridged transition metal complexes with cyclopentadienyl derivatives of alkali metals or alkaline earth metals and heating the reaction mixture obtained in this way to a temperature in the range from ?78 to 250° C., to the corresponding metallocene biphenoxide complexes and to their use as catalysts or as constituents of catalysts for the polymerization of olefinically unsaturated compounds or as reagents or catalysts in stereoselective synthesis.

Abstract: A process for producing organic substituted aromatic or heteroaromatic compounds including biaryl and biheteroaryl compounds in a two-step reaction. In the first step, the aromatic or heteroaromatic compound is borylated in a reaction comprising a borane or diborane reagent (any boron reagent where the boron reagent contains a B—H, B—B or B—Si bond) and an iridium or rhodium catalytic complex. In the second step, a metal catalyst catalyzes the formation of the organic substituted aromatic or heteroaromatic compound from the borylated compound and an electrophile such as an aryl or organic halide, triflate (OSO2CF3), or nonaflate (OSO2C4F9). The steps in the process can be performed in a single reaction vessel or in separate reaction vessels. The present invention also provides a process for synthesis of complex polyphenylenes starting from halogenated aromatic compounds.

Abstract: A transition metal complex represented by the formula (1): wherein M is a Group 4 transition metal, A is a Group 16 element, B is a Group 14 element, n is an integer of 0 or 1, R1, R2, R3 and R4 may be the same or different and each independently denotes a substituent selected from the group consisting of the groups (I) and (II): group (I): hydrogen, alkyl and so on, group (II): alkoxy, alkylthio and so on, provided that at least one of R1, R2, R3 and R4 is a substituent selected from group (II); R5, R6, R7, R8, R9, R10, X1 and X2 may be the same or different and are each hydrogen, halogen, alkyd or the like; and a catalyst for olefin polymerization comprising said complex, an organoaluminum compound and a boron compound are provided.

Abstract: Metallocenes and catalyst systems for olefin polymerization derived therefrom. The metallocenes may be represented by the formula: wherein M1 preferably is zirconium or hafnium; and R12 is different from hydrogen.

Abstract: A process for preparing dihalide or monohalide metallocene compounds comprising contacting a compound of formula (II) (Cp)(ZR1m)n(A)rML?y (II) wherein Cp is a cyclopentadienyl radical; (ZR1m)n is a divalent bridging group between Cp and A; A is a cyclopentadienyl radical or O, S, NR2, PR2 wherein R2 is an hydrocarbon radical, M is zirconium, titanium or hafnium.

Abstract: Organometallic transition metal compounds of the formula (I) where M1 is an element of group 3, 4, 5 or 6 of the Periodic Table of the Elements or the lanthanides; X are identical or different and are each halogen, hydrogen, C1–C20-alkyl, C2–C20-alkenyl, C6–C22-aryl, alkylaryl or arylalkyl having from 1 to 10 carbon atoms in the alkyl part and from 6 to 22 carbon atoms in the aryl part, —OR5 or —NR5R6, where two radicals X may also be joined to one another or two radicals X may together form a substituted or unsubstituted diene ligand, in particular a 1,3-diene ligand; where R5 and R6 are each C1–C10-alkyl, C6–C15-aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroaryl each having from 1 to 10 carbon atoms in the alkyl radical and from 6 to 22 carbon atoms in the aryl radical; n is a natural number from 1 to 4 which is equal to the oxidation number of M1 minus 2; R1 is a C2–C40 radical which is branched in the ? position; R2 is hydrogen or a C1–C40 radical which may be branched or unbranched in the ? position;

Abstract: The present invention relates to a specific process for the diastereoselective synthesis of rac-diorganosilylbis(2-methylbenzo[e]indenyl)zirconium compounds of the formula I, by reacting the silyl-bridged bisindenyl ligand with a dihalozirconium bis(3,5-di-tert-butylphenoxide)-base adduct to form the diorganosilylbis(2-methylbenzo[e]indenyl)zirconium bis(3,5-di-tert-butylphenoxide) and subsequently replacing the phenoxide groups by X using suitable replacement reagents to give the compound of the formula I; where the substituents X can be identical or different and are each F, Cl, Br, I or linear, cyclic or branched C1-10-alkyl; and the substituents R can be identical or different and are each linear, cyclic or branched C1-10-alkyl or C6-10-aryl; and also to the use of these compounds as catalysts.

Abstract: Group 4 metal constrained geometry complexes comprising tricyclic 4-arylsubstituted indenyl ligands, especially 1,5,6,7-tetrahydro-4-aryl-s-indacen-1-yl ligands, catalytic derivatives thereof, processes for preparing the same and their use as components of olefin polymerization catalysts are disclosed.

Abstract: The present invention relates to ligands and the synthesis of those ligands for use in metallocene complexes. More particularly, the present invention relates to the synthesis of diarylsilyl bridged biscyclopentadienes using diarylsilyldisulfonates. Even more particularly, the present invention describes Group IV metallocenes containing diarylsilyl bridged bis-cyclopentadienyl ligands prepared from contacting a diarylsilyldisulfonate with an organometallic indenyl reagent.

Abstract: Metal complexes, catalysts derived therefrom, and polymerization processes using the same, characterized by the presence of one or more nitrogen and boron containing, anionic 5-membered cyclic ligand groups, especially 1,2-azaborolyl groups, are disclosed.

Abstract: The present invention relates to a process for preparing specific transition metal compounds, novel transition metal compounds and also catalyst systems and their use for the homo- or copolymerization of olefins.

Abstract: The invention is a catalytic process using a Group IV B transition metal component and an alumoxane component to polymerize ?-olefins to produce high crystallinity and high molecular weight poly-?-olefins.

Abstract: A process for the preparation of indanones of the formula II from indanones of the formula I or of indanones of the formula IIa from indanones of the formula Ia comprises reacting an indanone of the formula I or Ia with a coupling component.

Abstract: Various catalyst compositions including the contact product of at least one ansa-metallocene compound, at least one organoaluminum compound, and at least one activator-support are disclosed. Processes for forming such compositions and for forming polyolefins with such compositions are also disclosed. Metallocene compounds are also presented.

Abstract: Chiral organometallic compounds are provided which comprise certain non-symmetrically substituted cyclopentadiene complexed to a transition metal. The cyclopentadiene has a second coordinating group which also complexes the transition metal and is attached to the cyclopentadiene by means of a chiral connecting chain. Preferred transition metals include rhodium, ruthenium, iridium, cobalt, iron, manganese, chromium, tungsten, molybdenum, nickel, palladium, or platinum. These chiral organometallic compounds find use in asymmetric synthesis to produce chiral compounds.

Abstract: The present invention provides metallocene compounds which exhibit high polymerization activity for production of highly stereoregular polymers, as well as a production process for olefin polymers which employs olefin polymerization catalysts containing the compounds, and olefin polymers obtained by the production process.

Abstract: A process for the preparation of an olefin polymer by polymerization or copolymerization of an olefin of the formula Ra—CH?CH—Rb, in which Ra and Rb are identical or different and are a hydrogen atom or a hydrocarbon radical having 1 to 14 carbon atoms or Ra and Rb, together with the atoms connecting them, can form a ring, at a temperature of from ?60° to 200° C., at a pressure of from 0.

Abstract: The novel metallocenes of the formula I in which, preferably, M1 is Zr or Hf, R1 and R2 are alkyl or halogen, R3 and R4 are hydrogen, R5 and R6 are alkyl or haloalkyl, —(CR8R9)m—R7—(CR8R9)n— is a single- or multi-membered chain in which R7 may also be a (substituted) hetero atom, m+n is zero or 1, and R10 is hydrogen, form, together with aluminoxanes as cocatalysts, a very effective catalyst system for the preparation of polyolefins of high stereospecificity and high melting point.

Abstract: The novel metallocenes of the formula I in which, preferably, M1 is Zr or Hf, R1 and R2 are alkyl or halogen, R3 and R4 are hydrogen, R5 and R6 are alkyl or haloalkyl, —(CR8R9)m—R7—(CR8R9)n— is a single- or multi-membered chain in which R7 may also be a (substituted) hetero atom, m+n is zero or 1, and R10 is hydrogen, form, together with aluminoxanes as cocatalysts, a very effective catalyst system for the preparation of polyolefins of high stereospecificity and high melting point.

Abstract: The present invention relates to zwitterionic neutral transition metal compounds. The compounds are suitable as catalyst components for the polymerization of olefins.