Abstract: Polysubstituted cyclopentadiene-containing compound, in which at least one substituent is has the formula --RDR'.sub.n, in which R is a linking group between the cyclopentadiene and the DR'.sub.n group, D is a hetero atom selected from group 15 or 16 of the Periodic Table of Elements or an aryl group, in which case R has at least the length of an ethylene group, R' is a hydrocarbon radical containing 1-20 carbon atoms (e.g., alkyl, aryl, aralkyl,. and the like, including straight chain, branched, cyclic, and derivatives thereof, and n is the number of R' groups bound to D (note that the R' groups may be identical or different).

Abstract: New metallocene ligand systems and catalysts/catalyst precursors are described where the ligand system contains at least one open-pentadienyl ligand characterized by an acyclic six .pi. electron delocalized, five atomic center structure. The open pentadienyl ligand is bonded to either another pentadienyl ligand or a Cp ligand by a bridging group. The metal is from group 3-5 or the Lanthanides. These metallocene catalysts/catalyst precursors optionally in combination with co-catalysts can be used to generate a wide variety of different polymer types including HDPE, LLDPE, LHDPE, ethylene/propylene elastomers, tactiospecific C3+ .alpha.-olefins, intimate mixture thereof and the like.

Abstract: A process for the production of a catalyst precursor comprising reacting (a) a metallocene dihalide; (b) a compound of the formula: ##STR1## wherein each Q is the same or different and is independently selected from the group consisting of O, NR, CR.sub.2, and S; E is either C or S; Z is selected from the group consisting of --OR, --NR.sub.2, --CR.sub.3, --SR, --SiR.sub.3, --PR.sub.2, --H, and a substituted or unsubstituted aryl group; and each R is independently a group containing carbon, silicon, nitrogen, oxygen, and/or phosphorus; and (c) a trialkylamine.

Abstract: Polysubstituted cyclopentadiene compound wherein at least two different substituents are present from the group consisting of linear, branched and cyclic alkyls, aralkyls and alkenyls, and a process for the preparation of a cyclopentadiene compound substituted with at least two different groups chosen from the group consisting of linear, branched, cyclic and aromatic alkyls and alkenyls, characterized in that it comprises the reacting of a halide of a first substituting group in a mixture of the cyclopentadiene compound and an aqueous solution of a base, in which the quantity of the base relative to the cyclopentadiene compound is between 5 and 30 mol/mol, in the presence of a phase transfer catalyst, followed by the addition of a halide of a second or optionally a third substituting group to the reaction mixture.

Abstract: The present invention relates to a stereorigid metallocene compound having as ligands at least two substituted or unsubstituted cyclopentadienyl groups which are connected to one another via a five-membered ring, where at least one cyclopentadienyl group is fused onto the five-membered ring and the ligand system of the stereorigid metallocene compound is different from 4-[.eta..sup.5 -3'-alkylcyclopentadienyl)-4,6,6-trimethyl-(.eta..sup.5 -2-alkyl-4,5-tetrahydropentalene]. The metallocene compound of the invention is suitable as a catalyst component for olefin polymerization.

Abstract: Compositions and methods for the solid phase synthesis of organic compounds are provided. The compositions are solid supports having an attached traceless linker precursor and are represented by the formula: ##STR1## In this formula, S.sup.0 is a solid support; B is a connecting group; M is a transition metal, for example ruthenium, chromium, iron, molybdenum and manganese; each L is independently a transition metal ligand; the letter n represents an integer of from 1 to 4, such that M has a sufficient number of ligands to fill the available valences; and X.sup.- represents an anion which is typically a non-nucleophilic anion.

Abstract: This invention relates to an three-constituent adduct of a metallocene.an ether.an metal halide having the general formula of Cp'MQ.sub.2.RXR'.nM'Q.sub.2/n, where Cp' is a substituted or an unsubstituted dicyclopentadienyl, M is zirconium or titanium, RXR' is tetrahydrofuran or diethylether, M' is alkali metal or alkali earth metal, n=1 or 2. The adduct can be exposed to air for several hours or stored in nitrogen atmosphere for a long period of time, which is prepared by means of a simple and convenient process without further separation and purification and used directly as a catalyst for polymerization of olefins.

Abstract: Metallocene compounds having two fluorenyl ligands bridged with a single silicon or germanium atom, said atom having two substituent groups containing a total of at least four carbon atoms, are useful as catalyst components for the polymerization of olefins. Particularly, it is possible to prepare high molecular weight atactic polypropylene with improved yields with respect to the known catalysts.

Abstract: A very effective catalyst system for the polymerization or copolymerization of olefins comprises a cocatalyst, preferably an aluminoxane or a supported aluminoxane, and a metallocene of the formula I ##STR1## in which, in the preferred form, M.sup.1 in Zr or Hf, R.sup.1 and R.sup.2 are halogen or alkyl, R.sup.3 is alkyl, R.sup.4 to R.sup.12 are alkyl or hydrogen and R.sup.13 is a (substituted) alkylene or heteroatom bridge. The metallocenes, in particular the zirconocenes, produce polymers of very high molecular weight, in the case of prochiral monomers polymers of very high molecular weight, very high stereotacticity and very high melting point, at high catalyst activities in the industrially particularly interesting temperature range between 50 and 80.degree. C. In addition, reactor deposits are avoided by means of supported catalyst systems.

Abstract: A class of metallocene compounds having two substituted cyclopentadienyl rings bridged by an alkylidene group wherein the cyclopentadienyl groups can be indenyl groups. The metallocene compounds have the following structures: ##STR1## The metallocenes are characterized by three principal features: (i) the cyclopentadienyl groups are substituted at the 3-position with a substituent other than hydrogen, while R.sup.2 in the 2-position bears a hydrogen (formula (I)) or is part of a condensed benzene ring (formula (II)); (ii) the bridge is a substituted-methylene bridge, i.e. a methylene group bearing at least one substituent other than hydrogen (R.sup.6 is always different from hydrogen); and (iii) the cyclopentadienyl groups are identically substituted (page 2, line 23). These metallocene compounds can be suitably used as catalyst components for the polymerization of olefins.

Abstract: A method is provided for synthesizing metallocene compounds useful as polymerization catalysts and the like. The method involves (a) preparation of an amino alcohol-derived ligand by reacting a silane reactant with an amino alcohol in the presence of base, followed by (b) metallation of the ligand so provided. The metallocenes may be provided in chiral form when the amino alcohol contains an asymmetric center, and are thus useful in catalyzing stereospecific polymerization and other stereospecific bond formation reactions.

Abstract: Bridged, group 4 Metal complexes useful as olefin polymerization catalyst components corresponding to the formula: L.sub.1 ZL.sub.2 MX.sub.m X'.sub.nor a dimer, solvated adduct, chelated derivative or mixture thereof, wherein:L.sub.1 is a partially saturated tricyclic group, especially octahydrofluorenyl,L.sub.2 is a substituted cyclopentadienyl group that is bound to M by means of delocalized .pi.-electrons, said cyclopentadienyl group being substituted at one and only one of its two distal positions with a bulky ligand group,Z is divalent bridging substituent,X each occurrence is a monovalent, anionic moiety having up to 40 non-hydrogen atoms, optionally, two X groups may be covalently bound together forming a divalent dianionic moiety having both valences bound to M, or, optionally 2 X groups may be covalently bound together to form a neutral, conjugated or nonconjugated diene that is bonded to M by means of delocalized .pi.

Abstract: An organic aluminoxy compound which shows .sup.27 Al nuclear magnetic resonance spectrum (.sup.27 Al-NMR spectrum) having an A.sub.1 /A.sub.2 ratio of at most 0.1, wherein A.sub.1 is area of a region encompassed by a segment of a line which connects a local minimum point existing between a continuous curve "a" containing a peak appearing at around 150 ppm and a continuous curve "b" containing a peak appearing at around 60 ppm to the point where the above curve "b" comes into contact with the base line and also by the above curve "b" and A.sub.2 is area of a region encompassed by the above curves "a" and "b" and also by the base line; an organic aluminoxy compound containing at least 5%, expressed in terms of aluminum atom, of a portion insoluble in a mixed solvent of toluene and hexane in a ratio by volume of 2:5 at 30.degree. C. or lower; and a catalyst for producing a polymer comprising any of the above organic aluminoxy compounds and a transition metal compound.

Abstract: Group 4 metal constrained geometry complexes comprising a fused ring indenyl derivative ligand, catalytic derivatives thereof, processes for preparing the same and their use as components of olefin polymerization catalysts are disclosed.

Abstract: It is shown metallocences with functionalized bridge of formula ##STR1## wherein M represents a transition metal from groups 3, 4, 5 or 6, L represents cyclopentadienyl-type ligands, Y represents a halogen and which can own one or various bridges between unities L. At least one of these bridges is functionalized through a group constituted by the union between a halogen atom and a silicon, germanium or tin atom. It is also shown a method for the synthesis of these metallocene compounds starting from the corresponding metallic halure and a precursor of the ligand with leaving groups. The functionalization shown by these compounds give them a peculiar reactivity that can be used for the formation of new metallocene derivatives, including bi- or poly-metallocene compounds. This reactivity is shown in the present document through examples with alcohol-type substrates.

Abstract: A practical and scalable process for the synthesis of constrained geometry metallocene catalyst is described.

Abstract: Group 4 metal complexes comprising an indenyl group substituted in the 2 or 3 position with at least one group selected from hydrocarbyl, fluoro-substituted hydrocarbyl, hydrocarbyloxy-substituted hydrocarbyl, dialkylamino-substituted hydroacrbyl, silyl, germyl and mixtures thereof, said indenyl group further being covalently bonded to the metal by means of a divalent ligand group, catalytic derivatives thereof and their use as olefin polymerization catalysts are disclosed.

Abstract: Metal complexes having constrained geometry and a process for preparation thereof, addition polymerization catalysts formed therefrom, processes for preparation of such addition polymerization catalysts, methods of use, and novel polymers formed thereby, including ElPE resins and pseudo-random copolymers, are disclosed and claimed.

Abstract: Bridged metallocenes of Group IVb metals provide improved results when the bridge comprises a neutral electron-donor substituent of general formulaR'" Z R"".sub.jwhereinR'" is a rigid unsaturated hydrocarbon radical between Z and the bridge, such that Z is separated from the bridge by 2 to 5 carbon atomsZ is nitrogen, phosphorus, oxygen or sulphur,R"" is H or an alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl having a maximum of 15 carbon atoms, each R"" being the same or different,j is 1 when Z=O or S and 2 when Z=N or P.

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

Abstract: The process of preparing ansa-metallocene complexes in high yield by reacting a metal leaving group complex with an aluminum ansa-bis-cyclopentadienyl compound.

Abstract: A specific amount of a low molecular weight vinyl siloxane is blended with a platinum-vinyl siloxane complex to provide a platinum complex catalyst, which is prevented from deterioration with time at elevated temperatures and from blackening and precipitation, and maintains its catalytic activity unaffected.

Abstract: The invention relates to an indenyl compound of the general formulaR'Ind--M--(Cp)Q.sub.kin which the symbols have the following meanings:Ind: an indenyl groupR': a substituent, other than hydrogen, to the Ind group,Cp: a cyclopentadienyl groupM: a transition metal from group 3, 4, 5 or 6 of the Periodic System of ElementsQ: a ligand to Mand k is an integer linked to the valence of M.The invention is characterized in that the R' group is bound to the Ind group at the 2-position. The indenyl compound is a catalyst component for the polymerization of olefins. The invention also relates to polymers obtainable with such indenyl compounds.

Abstract: A novel metallocene compound and a method for producing a polymer by using the metallocene as a polymerization catalyst. The present catalyst includes a neutral metallocene compound, a cationic metallocene compound, and the compound supported catalyst. The present catalyst can be used to produce a polymer having a characteristic structure and physical properties.

Abstract: Catalyst component for the polymerization of alpha-olefins of general formula (I) ##STR1## wherein: M is a transition metal of groups 3, 4-10, lanthanide or actinide of the periodic table of the elements; A is a ring with delocalized .pi. electrons, L is a neutral Lewis base; m is an integer whose value can be: 0 or 1; E is selected from the group comprising: BR.sup.II, CR.sup.II.sub.2, SiR.sup.II.sub.2, GeR.sup.II.sub.2 ; Hal is selected from the group comprising iodine, bromine or chlorine; R.sup.III has the same meaning of R.sup.II ; Si is a silicon atom; D is selected from the group comprising: O, S, NR.sup.IV, PR.sup.IV, OR.sup.IV, SR.sup.IV, NR.sup.IV.sub.2, PR.sup.IV.sub.2 ; each X group equal to or different from each other is selected from the group comprising hydrogen, halide, alkyl, cycloalkyl, aryl, alkenyl, arylallyl, arylalkenyl or alkylaryl with 1 to 20 carbon atoms, n is a number whose value can be: 0, 1, 2 or 3, in order to full the remaining valences of metal M.

Abstract: It is possible to prepare in high yield and purity the racemic and meso forms of bridged chiral metallocenes with a stereoselective method, by synthesizing the sylil-, germyl- or stannyl-substituted ligands. These compounds can be prepared in their racemic and meso forms, and then selectively transformed in the corresponding metallocenes.

Abstract: The present invention relates to a catalyst system based on monoazadiene metal complexes of the formula ##STR1## and a co-catalyst suitable for activating the metal complex, and to the use of the catalyst system for the polymerization of unsaturated compounds, especially for the polymerization and copolymerization of olefins and/or dienes.The novel catalyst system is characterised in particular by its ease of access, its lack of sensitivity to external influences and its ease of handling.

Abstract: Group 4 metal constrained geometry complexes comprising a fused ring indenyl derivative ligand, catalytic derivatives thereof, processes for preparing the same and their use as components of olefin polymerization catalysts are disclosed.

Abstract: A method for producing a bridged type transition metal complex represented by the following formula (1), comprising the following steps (i) and (ii):step (i); a step for reacting a specific cyclopentadiene compound with an organic alkaline metal compound or an organomagnesium compound to produce an alkaline metal salt compound or a magnesium salt compound of the cyclopentadiene compound; andstep (ii); a step for reacting the alkaline metal salt compound or magnesium salt compound of the cyclopentadiene compound with a specific transition metal compound, wherein at least the step (ii) is performed in the presence of an amine compound.According to the present invention, there can be provided a method for producing a bridged type transition metal complex having one cyclopentadiene type anion skeleton on an industrial scale in high yield without requiring an industrially disadvantageous low temperature and replacement of the solvent, which is capable of reducing the number of the steps.

Abstract: It has been discovered that the meso form of metallocenes can be catalytically isomerized to the racemic form of the metallocene. This is accomplished by heating an isomerization mixture formed from (i) a meso form of a bridged metallocene or a mixture of meso and racemic forms of a bridged metallocene, (ii) a Group 1 and/or 2 metal halide isomerization catalyst, and (iii) a liquid organic isomerization medium, such that at least a portion of the meso form of the metallocene is isomerized to the racemic form.

Abstract: A method for the synthesis of certain N-silylated cyclopentaphenanthrene (Group IV metal) complexes is disclosed.

Abstract: Zirconocenes and hafnocenes with borylated cyclopentadienyl ligands and methods for the preparation thereof.

Abstract: A process for the preparation of a polyolefin wax If a catalyst consisting of an aluminoxane and a metal-locene of the formula I ##STR1## in particular R.sup.5 R.sup.6 C (Ind).sub.2 or R.sup.5 R.sup.6 C (Ind).sub.2 Zr(CH.sub.3).sub.2, is employed for the polymerization of olefins of the formulaR.sup.9 CH.dbd.CHR.sup.10(R.sup.9, R.sup.10 =H or C.sub.1 -C.sub.28 alkyl), the isotacticity of the polymer wax and hence the hardness and melting point can be varied simply by changing the polymerization temperature, without the molecular weight of the polymer being noticeably changed at the same time.

Abstract: The present invention relates to a multinuclear metallocene compound of the formula I, ##STR1## where M.sup.1 is a tetravalent metal, L.sup.1 are, independently of one another, identical or different and are each a substituted cyclopentadienyl group, L.sup.2 and L.sup.3 are, independently of one another, identical or different and are each a .pi. ligand, B are, independently of one another, identical or different and are each a divalent bridging unit, X are, independently of one another, identical or different and are each a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.10 -fluorocarbon radical or a hydrocarbon-containing radical having 1-40 carbon atoms, and k is an integer from 0 to 10. The metallocene compound of the present invention is suitable as a catalyst component for preparing olefin polymers.

Abstract: Disclosed is a monocyclopentadienyl metal compound that can polymerize polyolefins as part of a catalyst system. The monocyclopentadienyl compound can specifically be (C.sub.5 H.sub.4 CH.sub.2 CH.sub.2 NMe.sub.2)TiCl.sub.3.

Abstract: Described are certain monocyclopentadienyl Group IV B metal compounds, catalyst systems comprising such monocyclopentadienyl metal compounds and an activator, and a process using such catalyst systems for the production of polyolefins, particularly high molecular weight ethylene-.alpha.-olefin copolymers having a high level of .alpha.-olefin incorporation.

Abstract: Catalytic component for the copolymerization of ethylene with alpha-olefins having general formula (I): ##STR1## wherein: A is a cyclopentadienyl derivative having general formula (II) ##STR2## B is selected from: 1) any of the cyclopentadienyl derivatives A defined above2) a monofunctional cyclopentadienyl radical (F) selected from cyclopentadienyl, indenyl, fluorenyl and the relative alkyl, aryl, trialkylsilyl substituted derivatives;Q, a bridge between A and B, is a bifunctional radical.

Abstract: Metallocene catalyst components having bis-fluorenyl ligands of a staggered conformation and processes for the isotactic propagation of a polymer chain from ethylenically unsaturated monomers. The catalyst components comprise bridged bis-fluorenyl metallocenes characterized by the following formula:X(F1Y.sub.a)(F1'Z.sub.b)MeQ.sub.n (1)wherein, F1 and F1' are fluorenyl groups which are interconnected by a structural bridge X to impart stereorigidity to the metallocene ligand, Me is a Group 3, 4, or 5 transition metal each Y is the same or different and is a hydrocarbyl or heterohydrocarbyl substituent at a distal position on the fluorenyl group, each Z is the same or different and is a hydrocarbyl or heterohydrocarbyl substituent at a distal position on the other fluorenyl group F1', and a and b are each independently 1 or 2.

Abstract: The invention relates to a process of preparing a 2-alkyl-2,3-dihydro-1H-benz?e!indene-1-one derivative, preferably 2,3-dihydro-2-methyl-benz?e!indene-1-one, characterized in that a naphthalene derivative is condensed with an active ester of 2-alkyl-2-propenoic acid, preferably with 2-methyl-2-propenoyl chloride. The product which is obtained in high yield and substantially free from its isomer is an intermediate in the preparation of rac-dimethyl bis(2-alkyl-1H-benz?e!indenyl)silandiyl zirconium dichloride complex.

Abstract: Metallocene complexes of a metal M selected from titanium, zirconium and hafnium, comprising at least one anionic group A containing an .eta..sup.5 -cyclopentadienyl ring co-ordinated with the metal M, wherein the anionic group is substituted in at least one position of the cyclopentadienyl ring with a radical having the formula:Ph*--(CR.sup.6 R.sup.7).sub.nwherein: R.sup.6 and R.sup.7 are independently hydrogen, halogen or a C.sub.1 -C.sub.4 alkyl group, preferably hydrogen, "n" is 0 or 1, preferably 1, Ph* is a C.sub.6 -C.sub.14 group comprising an aromatic ring linked to --CR.sup.6 R.sup.7 -- or to A and substituted with at least one and up to a maximum of three electron-attractor groups, on the condition that, when A is an .eta..sup.5 -indenyl group and "n" is 0, at least one Ph group is linked to A in position 1 or 3 of indenyl.These complexes can be used in (co)polymerization processes of .alpha.

Abstract: A metallocene having one or two hydrocarbyl groups bonded to a Group 4 metal are produced from a crude impure pasty or non-wet mixture containing at least 50% by weight of a metallocene having two halogen atoms bonded to a Group 4 metal atom, by (a) mixing liquid aromatic hydrocarbon with the crude impure pasty or non-wet mixture; (b) mixing a solution of an organolithium compound in a suitable anhydrous ether or paraffinic hydrocarbon solvent or a mixture thereof, with the mixture from (a) and agitating the resulting mixture so that lithium halide solids are formed; and (c) separating the solids and recovering the resultant liquid portion which is mainly a solution of the metallocene having one or two hydrocarbyl groups bonded to a Group 4 metal. Additional optional steps include (d) replacing the original solvent from the solution from (c) with a liquid paraffinic hydrocarbon diluent to form a slurry of product solids; and (e) recovering the product metallocene solids.

Abstract: A chiral, organometallic compound which, at a molecular level, has no C2 symmetry and comprises a carbon to carbon bond joining a chiral carbon atom to a carbon atom of a cyclopentadiene ring that is non-symmetrically substituted. Examples of such compounds include compounds of formula (I): ##STR1## wherein X.sup.1 and X.sup.2 are, independently, groups which are removable during a chemical reaction; M is titanium, zirconium or hafnium; and R.sup.1-8,11 are as specified in the description.

Abstract: The invention relates to a process for the preparation of a compound of the formula IV or IVa ##STR1## in which R.sup.1 -R.sup.5 are preferably hydrogen or alkyl, which comprises reacting a compound I ##STR2## with a compound II ##STR3## in which X.sup.1 and X.sup.2 are preferably halogen, to give the corresponding indanones, which are converted into the compounds IV and IVa by reduction and dehydration. The compounds IV and IVa are important intermediate products for the preparation of chiral metallocene complexes which are suitable catalyst components for olefin polymerization.

Abstract: Chiral compounds of the formula I ##STR1## where the variables are as described in the specification.

Abstract: Metallocene complexes of the formula I ##STR1## where M is titanium, zirconium, hafnium, vanadium, niobium or tantalum,n is an integer from 0 to 10,R.sup.5 is ##STR2## R.sup.11 to R.sup.14 are as designated in the disclosure, n.sup.1 is an integer from 0 to 10,X.sup.1 to X.sup.4 are each fluorine, chlorine, bromine, iodine, hydrogen, C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, --OR.sup.15 --, --NR.sup.15 R.sup.16 or ##STR3## R.sup.15 to R.sup.21 are as designated in the disclosure, and o, p, q, r are each an integer from 0 to 4, the sum o+p+q+r+1 corresponding to the valency of M,which were used as active catalyst components in the preparation of polymers of C.sub.2 -C.sub.10 -alkenes, are recovered by a process wherein the polymerization is stopped by adding an acid and the metallocene complexes of the formula I are recovered by extraction from the reaction mixture.

Abstract: The conversion of the achiral meso form of an ansa-metallocene complex into the chiral rac form is carried out photochemically in the presence of a chiral auxiliary reagent.

Abstract: A catalyst for polymerization of an olefin, which comprises (a) a transition metal compound of the following formula (1), (2) and/or (3): ##STR1## wherein each of M.sup.1, M.sup.2 and M.sup.3 is a titanium atom, a zirconium atom or a hafnium atom, each of Cp.sup.1, Cp.sup.2, Cp.sup.3, Cp.sup.4 and Cp.sup.5 is a cyclopentadienyl group, an indenyl group, a fluorenyl group or a substitution product thereof, R.sup.1 is a hydrogen atom, a C.sub.1-20 hydrocarbon group or a C.sub.1-20 alkylsilyl group, each of X.sup.1, X.sup.2, X.sup.3, X.sup.4, X.sup.5 and X.sup.6 is a hydrogen atom or a C.sub.1-20 hydrocarbon group, Z.sup.1 is a C.sub.1-20 hydrocarbon group, a silicon-containing C.sub.1-20 hydrocarbon group or a C.sub.1-20 alkylsilanediyl group, which serves to connect Cp.sup.3 and Cp.sup.4, Z.sup.2 is a C.sub.1-20 hydrocarbon group, a silicon-containing C.sub.1-20 hydrocarbon group or a C.sub.1-20 alkylsilanediyl group, which serves to connect Cp.sup.

Abstract: Racemic, bridged hafnocene is produced in enhanced yield by reacting a hafnium halide-aliphatic polyether adduct that has been formed and/or heated at one or more temperatures of at least about 40.degree. C., and a metallated bis(cyclopentadienyl-moiety-containing) ligand, at one or more temperatures for a sufficient period of time such that a racemic, bridged hafnocene is produced. The reaction is performed in the substantial absence of tetrahydrofuran and/or any other ether solvent or diluent that causes the formation of a tarry residue in the reaction mixture.

Abstract: A process for producing metallocene procatalysts useful in a catalyst system for the polymerization of olefins, particularly to make stereospecific polymers, and more particularly polymerization to make isotactic polypropylene in which the product of a reaction between a suitable ligand and an alkali-alkyl is reacted with a transition metal salt in the presence of an accelerant that has at least one lone pair of electrons in its outer valence shell. When the metallocene procatalyst produced is used in a catalyst system for the production of isotactic polymers, specifically isotactic polypropylene, the metallocene procatalyst can be used without isolating and separating the racemic modification from the meso form.

Abstract: It is possible to modify the rac/meso ratio of a rac/meso mixture in a stereorigid, bridged metallocene compound by subjecting a rac/meso isomeric mixture directly obtained from the synthesis to selective decomposition of the undesired isomer in the presence of compounds having either acidic hydrogen atoms or reactive halogen atoms. This process allows to prepare chiral metallocenes in their pure racemic or meso isomeric form.