Abstract: Chemically homogeneous cycloolefin copolymers of polycyclic olefins, such as, for example, norbornene or tetracyclododecene, with cycloolefins and/or acyclic olefins are obtained without ring opening and in a high space-time yield if a catalyst system is used which comprises an aluminoxane and a stereorigid metallocene compound of an element from groups IVb to VIb, of the formula the part of the metallocene molecule formed by M1 and the substituents R16-R17 having C1-symmetry or being in the meso-form.

Abstract: Fluorenyl-containing metallocenes are disclosed along with methods for making the metallocenes. Also disclosed are methods for using the metallocenes as polymerization catalysts. In addition, polymers resulting from such polymerizations are disclosed.

Abstract: A process of preparing in high yield racemic ansa-metallocene complexes by reacting a chelated bisamide group 4 metal complex with an ansa-bis-cyclopentodrenyl dianion reagent. The meso isomers are not detectable in the reaction product.

Abstract: Group 3-6 or Lanthanide metal complexes possessing two metal centers, catalysts derived therefrom by combining the same with strong Lewis acids, Bronsted acid salts, salts containing a cationic oxidizing agent or subjected to bulk electrolysis in the presence of compatible, inert non-coordinating anions and the use of such catalysts for polymerizing olefins, diolefins and/or acetylenically unsaturated monomers are disclosed.

Abstract: The present invention relates to a new metallocene having the formula (I) ##STR1## where M is a metal of group IVb, Vb or VIb of the Periodic Table of the Elements, in particular Ti, Zr and Hf,X are identical or different and are each a hydrogen atom, a C.sub.1 -C.sub.40 -hydrocarbon group such as a C.sub.1 -C.sub.10 -alkyl, C.sub.1 -C.sub.10 -alkoxy, C.sub.6 -C.sub.10 -aryl, C.sub.6 -C.sub.10 -aryloxy, C.sub.2 -C.sub.10 -alkenyl, C.sub.7 -C.sub.40 -arylalkyl, C.sub.7 -C.sub.40 -alkylaryl or C.sub.8 -C.sub.40 -arylalkenyl group, an OH group, a halogen atom or a pseudohalogen such as nitrile,R.sup.1 to R.sup.5 are identical or different and, independently of one another, are each a hydrogen atom, a C.sub.1 -C.sub.30 -hydrocarbon radical such as C.sub.1 -C.sub.20 -alkyl or C.sub.6 -C.sub.20 -aryl, or a carbon-containing radical having from 1 to 10 carbon atoms and one or more heteroatoms selected from the group consisting of O, N, Si, Ge and P, where in each case two adjacent radicals R.sup.4 and/or R.sup.

Abstract: Salts of (polyfluoroaryl)fluoroanions of aluminum, gallium, and indium are described. The (polyfluoroaryl)fluoroanions have the formula [ER'R"R'"F].sup..crclbar. wherein E is aluminum, gallium, or indium, wherein F is fluorine, and wherein R', R", and R'" is each a fluorinated phenyl, fluorinated biphenyl, or fluorinated polycyclic group.

Abstract: Polysubstituted cyclopentadiene compound, in which at least one substituent is of the form -RDR'.sub.n, in which R is a bonding group, D is a hetero atom selected from group 15 or 16 of the Periodic System of the Elements, R' is a substituent and n is the number of R' groups bonded to D, and in that at least one further substituent is a branched alkyl group.

Abstract: Abstract of the Disclosure: Catalyst systems for the polymerization of C.sub.2 -C.sub.10 -alk-1-enes contain, as active components,a) a metallocene complex of the general formula I ##STR1## where M is titanium, zirconium, hafnium, vanadium, niobium or tantalum, X is halogen or C.sub.1 -C.sub.8 -alkyl, Y is carbon, phosphorus, sulfur, silicon or germanium, Z is C.sub.1 -C.sub.8 -alkyl, C.sub.3 -C.sub.10 -cycloalkyl or C.sub.6 -C.sub.10 -aryl, R.sup.1 and R.sup.2 are identical or different and are each C.sub.1 -C.sub.4 -alkyl, R.sup.3 to R.sup.6 are identical or different and are each hydrogen or C.sub.1 -C.sub.8 -alkyl, or two adjacent radicals R.sup.3 and R.sup.4 and R.sup.5 and R.sup.6 in each case together form a hydrocarbon ring system of 4 to 15 carbon atoms and n is 0, 1 or 2, andb) an open-chain or cyclic alumoxane compound of the general formula II or III ##STR2## where R.sup.7 is C.sub.1 -C.sub.4 -alkyl and n is from 5 to 30.

Abstract: Novel metallocene compounds are provided which are useful as polymerization catalysts, particularly in the polymerization of addition polymerizable monomers such as olefinic or vinyl monomers. Preferred polymer compositions prepared using the novel catalysts are bimodal or multimodal in nature, typically having a bimodal or multimodal molecular weight distribution. The metallocenes are binuclear or multinuclear, and contain two or more chemically distinct active sites. Methods for synthesizing the novel catalysts are also provided, as are methods for using the novel compounds as homogeneous or heterogeneous polymerization catalysts.

Abstract: The present invention relates to a transition metal compound of the formula I ##STR1## where M.sup.1 is a metal of group IIIb, IVb or Vb of the Periodic Table of the Elements,R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are identical or different and are each a hydrogen atom, a halogen atom, a C.sub.1 -C.sub.40 -hydrocarbon-containing group, an --SiR.sup.5.sub.3, --NR.sup.5.sub.2, --Si(OR.sup.5).sub.3, --Si(SR.sup.5).sub.3 or --PR.sup.5.sub.2 radical, where R.sup.5 are identical or different and are each a halogen atom, a C.sub.1 -C.sub.10 -alkyl group or a C.sub.6 -C.sub.10 -aryl group, or two or more radicals R.sup.1, R.sup.2, R.sup.3 or R.sup.4 together with the atoms connecting them form a ring system,Y are identical or different and are each a hydrogen atom, a C.sub.1 -C.sub.40 -hydrocarbon-containing group, an OH group, a halogen atom or an NR.sup.5.sub.2 group,k is an integer which corresponds to the valence of the transition metal atom M.sup.1 minus two and if Y is a butadiene unit, k is 1,A is a bridge,R.

Abstract: Disclosed is a process for preparing bridged Group 4 metal complexes containing a neutral diene ligand starting from the corresponding novel, metal diene containing complexes by reaction thereof with the divalent derivative of a bridged bidentate ligand compound. The novel, intermediate metal diene complexes, their formation from tetravalent metal salts and an integrated process combining both process steps are claimed.

Abstract: In metal complexes of the formula I ##STR1## the substituents have the following meanings: M is a metal of transition group III, IV, V or VI of the Periodic Table of the Elements or a metal of the lanthanide series,Y is a negative leaving atom or a negative leaving group,X and X.sup.1 are negatively charged or uncharged atoms of main group IV, V or VI of the Periodic Table of the Elements,Z is hydrogen, C.sub.1 -C.sub.10 -alkyl, C.sub.3 -C.sub.10 -cycloalkyl, C.sub.1 -C.sub.10 -alkoxy, C.sub.1 -C.sub.10 -alkylthio or dialkylamido having from 1 to 4 carbon atoms in each alkyl radical,R.sup.1 to R.sup.11 are hydrogen, carboorganic or organosilicon radicals,n is 0, 1 or 2 andthe valence of M is 2+n.

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: A catalyst obtained by contacting (A) a compound of a transition metal of the group V of the Periodic Table represented by formula (I):R.sub.n M(O).sub.m X.sub.p .cndot.L.sub.

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: 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: 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: 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 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 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 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: Disclosed herein are processes for polymerizing ethylene, acyclic olefins, and/or selected cyclic olefins, and optionally selected olefinic esters or carboxylic acids, and other monomers. The polymerizations are catalyzed by selected transition metal compounds, and sometimes other co-catalysts. Since some of the polymerizations exhibit some characteristics of living polymerizations, block copolymers can be readily made. Many of the polymers produced are often novel, particularly in regard to their microstructure, which gives some of them unusual properties. Numerous novel catalysts are disclosed, as well as some novel processes for making them. The polymers made are useful as elastomers, molding resins, in adhesives, etc. Also described herein is the synthesis of linear .alpha.-olefins by the oligomerization of ethylene using as a catalyst system a combination a nickel compound having a selected .alpha.-diimine ligand and a selected Lewis or Bronsted acid, or by contacting selected .alpha.

Abstract: This invention relates to a process for polymerizing ethylene comprising contacting ethylene and optional comonomers with a catalyst system comprising an activator and a transition metal compound represented by the formula: ##STR1## Wherein R.sub.1 and R2 are independently hydrogen or a group having up to 100 carbon atoms, Cp.sub.1 is a bulky ligand; Cp.sub.2 is a bulky ligand or a heteroatom optionally bound to a C.sub.1 to C.sub.50 hydrocarbyl group, n is the valence state of the transition metal, Tm is a Group 3 to 10 metal, and each X is independently an anionic leaving group.

Abstract: The present invention relates to a novel fullerene-derived metallocene. Such fullerene-derived metallocene can be used as the catalyst for preparing olefin polymers.

Abstract: This invention relates to a method to produce pentfulvenes comprising combining a partially substituted cyclopentadiene with a carbonyl containing compound and lithium or an alkyl lithium, wherein the partially substituted cyclopentadiene is represented by the formula: ##STR1## wherein the R.sup.1 to R.sup.5 groups are independently hydrogen or a C.sub.1 to C.sub.100 group, provided at least one R group is hydrogen but not more than three R groups are hydrogen.

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: Tantalum and titanium source reagents are described, including tantalum amide and tantalum silicon nitride precursors for the deposition of tantalum nitride material on a substrate by processes such as chemical vapor deposition, assisted chemical vapor deposition, ion implantation, molecular beam epitaxy and rapid thermal processing. The precursors may be employed to form diffusion barrier layers on microlectronic device structures enabling the use of copper metallization and ferroelectric thin films in device construction.

Abstract: A novel metallocene catalyst for the polymerization of olefin (co)polymers is of the general formula:R--SO.sub.2 --L--M--(X).sub.m T.sub.nwherein,M is a metal selected from Groups 3-10;T is a polymerization-stable anionic ancillary ligand;m+n is the valency of M minus 1;R is a C.sub.1 -C.sub.20 alkyl group, a C.sub.6 -C.sub.20 aryl ring or a C.sub.6 -C.sub.20 alkaryl or aralkyl group, optionally substituted with a halogen or an alkoxy group up to 10 carbon atoms;X is a halogen, alkoxy from C.sub.1 to C.sub.20, siloxy from C.sub.1 to C.sub.20, N(R).sub.2, a hydrocarbyl group containing up to about 12 carbon atoms, hydrogen or another univalent anionic ligand, or mixtures thereof;L is T as defined above with the proviso that one of the sites available for substitution is the attachment site of the sulfonyl group; andwherein L and T may be bridged.

Abstract: The present invention relates to a novel fullerene-containing metallocene. Such a fullerene-containing metallocene can be used as the catalyst for preparing olefin polymers.

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: The present invention relates to a metallocene of the formula I, ##STR1## for preparing polyolefins, where M.sup.1 is preferably Zr, Hf or Ti, R.sup.1 and R.sup.2 are each a hydrogen atom, a C.sub.1 -C.sub.3 -alkyl group, a C.sub.1 -C.sub.3 -alkoxy group, a C.sub.6 -C.sub.8 -aryl group, a C.sub.6 -C.sub.8 -aryloxy group, a C.sub.2 -C.sub.4 -alkenyl group, a C.sub.7 -C.sub.10 -arylalkyl group, a C.sub.7 -C.sub.12 -alkylaryl group, a C.sub.8 -C.sub.12 -arylalkenyl group or chlorine, R.sup.3 is a chlorine atom, a C.sub.1 -C.sub.3 -alkyl group, a C.sub.2 -C.sub.4 -alkenyl group, a C.sub.6 -C.sub.8 -aryl group, an NR.sup.16.sub.2, SR.sup.16, OSiR.sup.16.sub.3, SiR.sup.16.sub.3 or PR.sup.16.sub.2 radical where R.sup.16 is chlorine, a C.sub.1 -C.sub.4 -alkyl group or a C.sub.6 -C.sub.8 -aryl group. R.sup.4 is a hydrogen atom, R.sup.13 is --(R.sup.14 M.sup.2 R.sup.15)--, --(R.sup.14 CR.sup.15)--(R.sup.14 CR.sup.15)--, --(R.sup.14 CR.sup.15)--(R.sup.14 M.sup.2 R.sup.15)-- or --(R.sup.14 CR.sup.15)--, where R.sup.

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 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 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 invention relates to a complex compound having at least one transition metal atom, characterized in that said complex compound contains at least one pentalene or substituted pentalene ligand which is coordinated to only one single metal atom.

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: Process for preparing a methylene-bridged cyclopentadienyl compoundThe present invention relates to a process for preparing a methylene-bridged biscyclopentadienyl compound having the formula I ##STR1## Where L are, independently of one another, identical or different and are each a cyclopentadienyl group, by reactin one or two cyclopentadienyl compounds LH with formaldehyde in monomeric, oligomeric or polymeric form or formaldehyde-generating reagents in the presence of at least one base and at least one phase transfer catalyst.

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: A novel metallocene catalyst for the polymerization of olefin (co)polymers is of the general formula:Benzothiazole--E--M--X.sub.m L.sub.nwhere,M is a transition metal of Groups 3-10 of the Periodic Table;E is sulfur or oxygen; E being bond to the transition metal and to the carbon atom between sulfur and nitrogen of the benzothiazole moiety;L is a polymerization-stable anionic ancillary ligand;X is a halogen, alkoxy from C.sub.1 to C.sub.20, siloxy from C.sub.1 to C.sub.20, N(R.sub.1).sub.2, a hydrocarbyl group containing up to about 12 carbon atoms or hydrogen or mixtures thereof; preferably X is halogen, methoxy, ethoxy or siloxy (R.sub.1).sub.3 SiO--, where R.sub.1 is alkyl from C.sub.1 to C.sub.20 ; andm+n equals the valency of the M minus 1.

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: 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: A process for the preparation of multinuclear cluster compounds by reacting a metal carbonyl with iodine, and use of these clusters and clusters derived from them, in diagnostic imaging. Novel multinuclear cluster compounds are also disclosed.

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: The present invention relates to a process for preparing racemic ansa-metallocene complexes I ##STR1## tin compounds II ##STR2## and a process for preparing tin compounds II. R.sup.1 to R.sup.9, M, and X are defined herein.

Abstract: The present invention relates to a stereorigid metallocene compound which has 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 fuzed to the five-membered ring and the ligand system of the stereorigid metallocene compound is different from 4-?(.eta..sup.5 -3'-alkyl-cyclopentadienyl)-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: 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.

Abstract: Novel metallocene compounds are provided which are useful as polymerization catalysts, particularly in the polymerization of addition polymerizable monomers such as olefinic or vinyl monomers. Preferred polymer compositions prepared using the novel catalysts are bimodal or multimodal in nature, typically having a bimodal or multimodal molecular weight distribution. The metallocenes are binuclear or multinuclear, and contain two or more chemically distinct active sites. Methods for synthesizing the novel catalysts are also provided, as are methods for using the novel compounds as homogeneous or heterogeneous polymerization catalysts.