Abstract: Titanium and zirconium complexes comprising a single, cyclic, delocalized n-bonded ligand group wherein the metal of said complexes is in the +2 formal oxidation state are prepared in high yield and purity by reaction of titanium and zirconium halides in the +3 or +4 oxidation state with an n-alkyl Grignard reagent. The complexes are used as catalyst components for .alpha.-olefin polymerization catalysts.

Abstract: A catalyst component for use in the polymerization of .alpha.-olefins, comprising a compound represented by the following general formula I!: ##STR1## wherein R.sup.1 s represent a hydrogen atom, a C.sub.1-6 hydrocarbon group or a C.sub.1-12 hydrocarbon group containing silicon; each of R.sup.2 and R.sup.3 which forms the condensed ring represents a divalent C.sub.3-20 saturated or unsaturated hydrocarbon group, provided that at least one of R.sup.2 and R.sup.3 forms a ring condensed with the cyclopentadiene which is a seven- to twelve-membered ring having an unsaturated bond inherent in R.sup.2 or R.sup.3 ; Q represents a C.sub.1-20 divalent hydrocarbon group, a silylene group, a silylene group with a C.sub.1-20 hydrocarbon group, a germylene group, or a germylene group with a C.sub.1-20 hydrocarbon group; X and Y represent H, a halogen, a C.sub.1-20 hydrocarbon group, or a C.sub.

Abstract: A highly effective catalyst system for the polymerization of olefins comprises a cocatalyst, preferably an aluminoxane, and a metallocene of the formula I ##STR1## where M.sup.1 =Zr or Hf, R.sup.1 and R.sup.2 =(C.sub.1 -C.sub.4)-alkyl or chlorine, R.sup.3, with the proviso that at least one of the radicals R.sup.3 is not hydrogen, =hydrogen, F, Cl, --OR.sup.7, --NR.sup.7 R.sup.8, --P(O)R.sup.7 R.sup.8, --P(OR.sup.7).sub.2 or SR.sup.7, R.sup.4 is a ##STR2## radical, and m plus n are zero or 1.

Abstract: Bridged monocyclopentadienyl derivatives of a Group 4 metal are prepared by contacting a corresponding bis(cyclopentadienyl) metal complex with an alkali metal derivative or alkaline earth metal derivative of a hydrocarbyl ligand R, which is optionally substituted with one or more amino, phosphino, ether, thioether, or silyl groups. The bis(cyclopentadienyl) Group 4 metal complexes can be prepared by contacting a compound corresponding to one of the formulas (Cp).sub.3 MQ.sub.n X.sub.t, (Cp).sub.2 MQ.sub.n X.sub.t+1, or CpMQ.sub.n X.sub.t+2 and a dianionic salt compound corresponding to the formula: (L.sup.+x).sub.y (Cp*-Z-Y).sup.-2 or ((LX').sup.+x).sub.y (Cp*-Z-Y).sup.-2. An addition polymerization catalyst comprising a bis(cyclopentadienyl) Group 4 metal complex and an activating cocatalyst, and an addition polymerization process using such a catalyst.

Abstract: A process for preparing bridged mono- and bis(cyclopentadienyl) metal dihydrocarbyloxy coordination complexes (I) by contacting in the presence of an aprotic organic diluent a metal compound of the formula M(OR).sub.4 with a dianionic salt compound. A process for preparing bridged mono- and bis(cyclopentadienyl)dihydrocarbyl metal coordination complexes (II) by contacting a complex (I) with a hydrocarbylation agent. A process for preparing bridged mono- and bis(cyclopentadienyl) metal dihalide coordination complexes (III) by contacting a complex (I) with a halogenation agent.

Abstract: 2,5-Reactive substituent group-containing siloles of the following general formula are provided ##STR1## wherein R.sup.1 to R.sup.4 may be the same or different and independently represent a monovalent hydrocarbon group having from 1 to 12 carbon atoms or a hydrogen atom, and R.sup.5 and R.sup.6 may be the same or different and independently represent a group selected from monovalent hydrocarbon-substituted sulfur, selenium, silicon, germanium, tin and phosphorus, or a halogen atom. Polycondensates of the siloles and processes for preparing the siloles and polycondensates are described.

Abstract: Polymers of C.sub.2 -C.sub.10 -alk-1-enes are prepared at from 0.5 to 3000 bar and from -50.degree. to 300.degree. C. using a catalyst system by a process in which the catalyst system used is one which contains, 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 fluorine, chlorine, bromine, iodine, hydrogen, C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl or --OR.sup.7,R.sup.7 is C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoraryl, where each alkyl radical is of 1 to 10 carbon atoms and each aryl radical is of 6 to 20 carbon atoms,R.sup.1 to R.sup.6 are each hydrogen, C.sub.1 -C.sub.10 -alkyl, 5-membered to 7-membered cycloalkyl, which in turn may carry C.sub.1 -C.sub.10 -alkyl radicals as substituents, C.sub.6 -C.sub.15 -aryl or arylalkyl, where two adjacent radicals together may furthermore be a cyclic group of 4 to 15, carbon atoms, or Si(R.sup.8).sub.3R.

Abstract: A process for preparing titanium or zirconium diene complexes wherein the metal is in the +2 formal oxidation state comprising contacting a conjugated or nonconjugated C.sub.4-40 diene compound with a hydrocarbyloxide containing precursor complex.

Abstract: A catalyst component for use in the polymerization of .alpha.-olefins, comprising a compound represented by the following general formula [I]: ##STR1## wherein R.sup.1 s represent a hydrogen atom, a C.sub.1-6 hydrocarbon group or a C.sub.1-12 hydrocarbon group containing silicon; each of R.sup.2 and R.sup.3 independently represents a divalent group selected from the group consisting of a hydrocarbon group having 3 to 30 carbon atoms and a silicon-containing hydrocarbon group having 1 to 30 carbon atoms and 1 to 6 silicon atoms, provided that at least one of R.sup.2 and R.sup.3 is said silicon-containing hydrocarbon group; Q represents a C.sub.1-20 divalent hydrocarbon group, a silylene group, a silylene group with a C.sub.1-20 hydrocarbon group, a germylene group, or a germylene group with a C.sub.1-20 hydrocarbon group; X and Y represent H, a halogen, a C.sub.1-20 hydrocarbon group, or a C.sub.

Abstract: A method for coupling tin-containing molecules via a Sn--Sn bond is described. The invention employs dehydrocondensation to link the Sn atoms of two molecules to form tin dimers as well as novel high molecular weight organotin polymers. In a preferred embodiment, catenated tin polymers are formed from hydrostannane precursors in the presence of a suitable metal catalyst. A particularly preferred method involves coupling dialkylstannane monomers in the presence of a metallocene catalyst to form polystannanes. Preferred catalysts include electropositive metals, such as Zr and Hf. The polystannanes are photolabile, decomposing readily under room light conditions.

Abstract: Novel Group 4 metal complexes containing one and only one cyclic delocalized, anionic, .pi.-bonded group wherein the metal is in the +4 formal oxidation state and having a bridged ligand structure, also referred to as constrained geometry complexes and a conjugated diene divalent anionic ligand group; catalytic derivatives of such complexes including novel zwiterionic complexes; and the use thereof as catalysts for polymerizing olefins, diolefins and/or acetylenically unsaturated monomers.

Abstract: Disclosed are processes for the preparation of new bridged cyclopentadienylmagnesium compounds of the general formula Q(CpR.sub.a)(Cp'R'.sub.a ')Mg, and the use thereof for preparing bridged metallocenes.

Abstract: Novel titanium or zirconium complexes containing one and only one cyclic delocalized, anionic, .pi.-bonded group wherein the metal is in the +2 formal oxidation state and having a bridged ligand structure, also referred to as constrained geometry complexes; catalytic derivatives of such complexes; methods of preparation; and the use thereof as catalysts for polymerizing olefins, diolefins and/or acetylenically unsaturated monomers.

Abstract: Compounds of the formula I ##STR1## wherein R.sub.1 is C.sub.1 -C.sub.8 alkyl, phenyl or phenyl which is substituted by 1 to 3 C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy groups; R.sub.2 and R.sub.3 are each independently of the other typically C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.12 cycloalkyl, phenyl, or C.sub.1 -C.sub.4 alkyl- or C.sub.1 -C.sub.4 alkoxy-substituted C.sub.5 -C.sub.12 cycloalkyl, or phenyl which is substituted by one to three identical or different members selected from the group consisting of C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or halogen; R.sub.10 and R.sub.11 are identical and are typically C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.12 cycloalkyl, C.sub.1 -C.sub.4 alkyl- or C.sub.1 -C.sub.4 alkoxy-substituted C.sub.5 -C.sub.12 cycloalkyl or phenyl which is substituted by 1 to 3 identical or different members selected from the group consisting of C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or halogen; or R.sub.10 and R.sub.11 are different and are C.sub.1 -C.sub.

Abstract: Metallocenes having benzo-fused indenyl derivatives as ligands, processes for their preparation and their use as catalysts A very effective catalyst system for olefin polymerization comprises a cocatalyst, preferably an aluminoxane, and a metallocene of the formula I ##STR1## in which, preferably, M.sup.1 is 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.10 are alkyl or hydrogen and R.sup.11 is a (substituted) alkylene or heteroatom bridge.

Abstract: Process for the preparation of an olefin polymer using metallocenes containing specifically substituted indenyl ligandsA highly effective catalyst system for the polymerization of olefins comprises a cocatalyst, preferably an aluminoxane, and a metallocene of the formula I ##STR1## in which, preferably M.sup.1 is Zr or Hf, R.sup.1 and R.sup.2 are alkyl or halogen, R.sup.5 is hydrogen or alkyl, R.sup.3 and R.sup.4 are alkyl, where R.sup.3, R.sup.4 and R.sup.5 may be halogenated, --(CR.sup.7 R.sup.8).sub.m --R.sup.6 --(CR.sup.7 R.sup.8).sub.n -- is a single- or multi-membered chain in which R.sup.6 may also be a (substituted) heteroatom, and m+n is zero or 1.

Abstract: Benzofluorenyl-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: This invention relates to a syndiospecific metallocene of a substituted iPr[(cyclopentadienyl)(fluorenyl)]zirconium dichloride containing long-chain terminal alkene, for example octenyl groups, on fluorene at C2/C7. The metallocene compound useful as a catalyst in the present invention is described by the general formula:R"(C.sub.5 H.sub.4)(C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n)MeQ.sub.pwherein (C.sub.5 H.sub.4) is a cyclopentadienyl ring and (C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n) is a fluorenyl radical; R' is a long chain alkene substituent having 5-20 carbon atoms on the fluorene ligand at C2 or C7, each R' may be the same or different; R" is a structural bridge between the (C.sub.5 H.sub.4) and (C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n) rings to impart stereorigidity; Q is a hydrocarbon radical or a halogen; Me is a Group IIIB, IVB, VB, or VIB metal; m=0 or 1; n=1; and p is the valence of Me minus 2.

Abstract: There is disclosed a method for effectively producing a silicon-containing pentacyclic compound, wherein the method comprises reacting (a) a 1,2-bis(hydrosilyl)benzene with (b) a cyclic diyne in the presence of (c) a platinum compound. There is also disclosed a method for effectively producing a silicon-containing ladder polymer having a complete ladder structure, wherein the method comprises reacting (a) a 1,2,4,5-tetrakis(hydrosilyl)benzene with (b) a cyclic diyne in the presence of (c) a platinum compound.

Abstract: This invention is for a metallocene catalyst component useful in preparing isotactic polyolefins, a catalyst system using this component and a process for polymerizing olefins using the catalyst component. The catalyst component consists of a bridged metallocene in which one of the cyclopentadienyl rings is substituted in a different manner from the other ring. One of the cyclopentadienyl ligands contains a bulky group in one and only one distal position and the other cyclopentadienyl ligand has bilateral or pseudobilateral symmetry. There is a steric difference between the two Cp rings.The catalyst component is a stereorigid metallocene described by the formula:R" (CpR.sub.n)(CpR'.sub.m)MeQ.sub.kwherein each Cp is a cyclopentadienyl or substituted cyclopentadienyl ring; each R.sub.n and R'.sub.

Abstract: The catalyst for olefin polymerization of the present invention contains R.sub.k.sup.1 R.sub.l.sup.2 R.sub.m.sup.3 M(SO.sub.3 R.sup.4) (M=Zr, Ti or Hf; R.sup.1-3 =a group having a cyclopentadienyl skeleton) as a catalyst component of a transition metal compound. According to the catalyst of the invention, an olefin polymer having excellent particle properties can be prepared with high polymerization activities, and further a copolymer having a narrow composition distribution can be prepared when two or more monomers are copolymerized. Of the above-mentioned transition metal compounds, a compound represented by the following formula is a novel compound unknown so far and shows excellent catalytic properties. ##STR1## (Cp=a group having a cyclopentadienyl skeleton, X=SO.sub.3 R, a halogen atom, R, OR, NR.sub.n, S(O).sub.q R, SiR.sub.3 or P (O).sub.q R.sub.

Abstract: Bridged, chiral metallocenes, processes for their preparation and their use as catalystsMetallocenes of the formula I ##STR1## in which, preferably, M.sup.1 is titanium, zirconium or hafnium, R.sup.1 is a radical ##STR2## in which M.sup.2 is carbon or silicon, R.sup.4 and R.sup.5 are identical and are hydrogen or an alkyl group, p is 1 or 2, R.sup.2 is hydrogen or an alkyl group and the radicals R.sup.3 are identical and are halogen or an alkyl group, form, together with an aluminoxane as a cocatalyst, a suitable catalyst system for olefin polymerization.

Abstract: A very active catalyst system for olefin polymerization comprises a cocatalyst, preferably an aluminoxane, and a metallocene of the formula I ##STR1## in which, preferably, M.sup.1 is Zr or Hf, R.sup.1 and R.sup.2 are alkyl or halogen, R.sup.3 is hydrogen, R.sup.4 to R.sup.6 and alkyl or aryl, --(CR.sup.8 R.sup.9).sub.m --R.sup.7 --(CR.sup.8 R.sup.9).sub.n is a single- or multi-membered chain, in which R' can also be a (substituted) hetero atom, and m+n is zero or 1.

Abstract: An organometal complex is provided which is represented by the general formula (1) below: ##STR1## wherein Cp.sup.1 and Cp.sup.2 are respectively a substituted or unsubstituted cyclopentadienyl group; R.sup.1 is a group selected from alkylene groups or arylalkylene groups having 1 to 20 carbons, dialkylsilylene groups, dialkylgermanylene groups, alkylphosphinediyl groups, or alkylimino groups and R.sup.1 crosslinking Cp.sup.1 and Cp.sup.2 together; m is 0 or 1; M is selected from titanium, zirconium, and hafnium; R.sup.2, R.sup.3, and R.sup.4 are independently hydrogen, a hydrocarbon group of 1 to 12 carbons, an alkoxyl group, or an aryloxy group; and MAO is a methylalumoxane group. This organometal complex is capable of producing selectively an olefin polymer without use of any other additional catalyst component.

Abstract: Group 4 metal complexes useful as addition polymerization catalysts are prepared by electrolysis of cyclopentadienyl metal complexes under inert electrolysis conditions.

Abstract: A catalyst system comprising certain bimetallic metallocenes and an alumoxane is provided together with a process for the preparation of high molecular weight ethylene-alpha olefin elastomers and ethylene-alpha-olefin nonconjugated diolefin elastomers wherein the requisite monomers are polymerized in the presence of the bimetallic metallocene/alumoxane catalyst system.

Abstract: Compounds of formula I ##STR1## wherein R.sub.1 is C.sub.1 -C.sub.8 alkyl, phenyl or phenyl which is substituted by 1 to 3 C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy groups; R.sub.2 and R.sub.3 are identical and are C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.12 cycloalkyl or C.sub.1 -C.sub.4 alkyl- or C.sub.1 -C.sub.4 alkoxy-substituted C.sub.5 -C.sub.12 cycloalkyl, or phenyl which is substituted by one to three identical or different members selected from the group consisting of C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy, --SiR.sub.4 R.sub.5 R.sub.6, halogen, --SO.sub.3 M, --CO.sub.2 M, --PO.sub.3 M,--NR.sub.7 R.sub.8 and --[.sup..sym. NR.sub.7 R.sub.8 R.sub.9 ]X.sup..crclbar. ; or R.sub.2 and R.sub.3 are different and are C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.12 cycloalkyl, C.sub.1 -C.sub.4 alkyl- or C.sub.1 -C.sub.4 alkoxy-substituted C.sub.5 -C.sub.12 cycloalkyl, phenyl or phenyl which is substituted by one to three identical or different members selected from the group consisting of C.sub.

Abstract: Cationic Group 4 or Lanthanide metal catalysts containing a single, delocalized n-bonded group are prepared by contacting a metal complex with a carbonium salt of a compatible, non-coordinating anion.

Abstract: A novel catalyst for polymerization of a vinyl compound is provided which comprises, as a catalyst component (A), an organometal complex represented by General Formula (1) below: ##STR1## where Cp.sup.1 and Cp.sup.2 are independently a substituted or unsubstituted cyclopentadienyl group; R.sup.1 is a group selected from alkylene groups or arylalkylene groups having 1 to 20 carbons, dialkylsillylene groups, dialkylgermanylene groups, alkylphosphinediyl groups, or alkylimino groups and R.sup.1 crosslinking Cp.sup.1 and Cp.sup.2 together; m is 0 or 1; M is titanium, zirconium, or hafnium; and R.sup.2, R.sup.3, and R.sup.4 are independently hydrogen hydrocarbon group of 1 to 12 carbons, an alkoxy group, or an aryloxy group, and a catalyst component (B) represented by the general formula (2) or (3) ##STR2## where n is an integer of from 4 to 60, and R.sup.5 is a hydrocarbon group. A process for producing a vinyl compound polymer which employs the catalyst defined above is also provided.

Abstract: Addition polymerization catalysts comprising a derivative of a titanium or zirconium in the +4 oxidation state prepared by metal center oxidation and cation complex formation of a reduced metal precursor complex via electron transfer in a single step by use of a neutral organic oxidant, optionally in the presence of a Lewis acid mitigator.

Abstract: The synthesis, and use as precatalysts of chiral organozirconium complexes for olefin polymerization are disclosed, having the structure (C.sub.5 R'.sub.4-x R*.sub.x) A (C.sub.5 R".sub.4-y R'".sub.y) M Q.sub.p, where x and y represent the number of unsubstituted locations on the cyclopentadienyl ring; R', R", R'", and R* represent substituted and unsubstituted alkyl groups having 1-30 carbon atoms and R* is a chiral ligand; A is a fragment containing a Group 13, 14, 15, or 16 element of the Periodic Table; M is a Group 3, 4, or 5 metal of the Periodic Table; and Q is a hydrocarbyl radical, or halogen radical, with 3.ltoreq.p.ltoreq.o. Related complexes may be prepared by alkylation of the corresponding dichorides. In the presence of methylalumoxane or triarylborane cocatalysts, these complexes form "cation-like" species which are highly active for olefin polymerization. In combination with a Lewis acid cocatalyst, propylene or other .alpha.

Abstract: A very effective catalyst system for olefin polymerization consists of a cocatalyst, preferably an aluminoxane, and a metallocene of the formula (I) ##STR1## in which, preferably, M.sup.1 is Zr, R.sup.1 and R.sup.2 are alkyl or halogen, R.sup.3 to R.sup.6 are alkyl, --(CR.sup.8 R.sup.9).sub.m --R.sup.7 --(CR.sup.8 R.sup.9).sub.n -- is a chain having one or more members, in which R.sup.7 can also be a (substituted) hetero atom, and m+n is zero or 1. The catalyst system leads to polymers of variable molecular weight and stereotacticity, depending on the substituents R.sup.3 to R.sup.6 chosen, at polymerization temperatures which are relevant in industry.

Abstract: A metallocene having an asymmetric ligand which is represented by the formula below and its enantiomer: ##STR1## and a process for producing a polyolefin using the same as a catalyst component. The metallocene and its enantiomer are particularly effective in the production of highly stereospecific polyolefins.

Abstract: A process for the preparation of sulfonated silicones is disclosed. The process comprises the steps of (a) hydrosilylating an olefin-terminal silylketene acetal with a hydrosiloxane; (b) treating the ketene acetal with a trialkylsilylsulfonyl chloride and (c) hydrolyzing the resulting .alpha.-trialkylsilyl ester to provide a salt of an .alpha.-sulfonate. Useful products of the process are also disclosed; they comprise several genera of .alpha.-sulfonate esters pendant from siloxanes and polysiloxanes. The products are useful as polymer electrolytes and as sustained or controlled release substrates for the administration of medicines.

Abstract: Olefins are polymerized in the presence of a homogeneous catalyst represented by the formula LTi(NR.sub.2).sub.3 wherein L is a .sub.II -bonded ligand selected from the group consisting of indenyl, C.sub.1 -C.sub.4 alkyl substituted indenyl, --OSiR.sub.3 substituted indenyl, R is a C.sub.1 -C.sub.4 alkyl group wherein each R attached to the same nitrogen atom is the same, but the R groups attached to different nitrogen atoms can be the same or different from those attached to the other nitrogen atoms.

Abstract: This invention relates to a syndiospecific metallocene of a substituted iPr[(cyclopentadienyl)(fluorenyl)]zirconium dichloride containing long-chain terminal alkene, for example octenyl groups, on fluorene at C2/C7. The metallocene compound useful as a catalyst in the present invention is described by the general formula:R"(C.sub.5 H.sub.4)(C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n)MeQ.sub.pwherein (C.sub.5 H.sub.4) is a cyclopentadienyl ring and (C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n) is a fluorenyl radical; R' is a long chain alkene substituent having 514 20 carbon atoms on the fluorene ligand at C2 or C7, each R' may be the same or different; R" is a structural bridge between the (C.sub.5 H.sub.4) and (C.sub.4 H.sub.4-m R'.sub.m C.sub.5 C.sub.4 H.sub.4-n R'.sub.n) rings to impart stereorigidity; Q is a hydrocarbon radical or a halogen; Me is a Group IIIB, IVB, VB, or VIB metal; m=0 or 1; n=1; and p is the valence of Me minus 2.

Abstract: Titanocenes of the formula I ##STR1## in which R.sup.1 are cyclopentadienyl.sup..crclbar. groups and R.sup.2 and R.sup.3 are aromatic radicals which are substituted in both ortho-positions by fluorine and, in addition, are substituted by an acyloxy group are suitable as photoinitiators for the photopolymerization of ethylenically unsaturated compounds.

Abstract: Catalyst and process for the stereospecific propagation of a polymer chain derived from an ethylenically unsaturated monomer which contains 3 or more carbon atoms or is substituted vinyl compound. The catalysts comprise stereorigid metallocenes in which a structural bridge is not required for stereorigidity. The ring structures of the metallocene catalyst are substituted cyclopentadienyl rings. The substituent groups on the cyclopentadienyl rings impart stereorigidity to the catalyst by virtue of a sterically hindered relationship between the rings sufficient to prevent rotation of the rings. The catalyst is contacted with a C.sub.3 + alpha olefin or other ethylenically unsaturated compound in a polymerization reaction zone and maintained in contact with the catalyst in the reaction zone under polymerization conditions to produce a sterospecific polymer.

Abstract: A racemic mixture of a chiral, silicon bridged transition metal metallocene, which is substantially free of meso isomer, is precipitated directly from a reaction mixture as it is formed by reacting an organic solvent solution of an alkali metal salt of a silicon bridged ligand with a transition metal tetrahalide-ether complex.

Abstract: The novel metallocenes of the formula I ##STR1## in which, preferably, M.sup.1 is Zr or Hf, R.sup.1 and R.sup.2 are alkyl or halogen, R.sup.3 and R.sup.4 are hydrogen, R.sup.5 and R.sup.6 are alkyl or haloalkyl, --(CR.sup.8 R.sup.9).sub.m --R.sup.7 --(CR.sup.8 R.sup.9).sub.n -- is a single- or multi-membered chain in which R.sup.7 may also be a (substituted) hetero atom, m+n is zero or 1, and R.sup.10 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 invention relates to a process for the preparation of a compound of the formula XI ##STR1## wherein preferably M.sup.1 is zirconium, the radicals R.sup.1 are alkyl, the radicals R.sup.2 are halogen or alkyl, R.sup.3 is dimethylsilyl or ethylene and n is 2-18, wherein a compound of the formula II ##STR2## is reacted with an alkali metal or alkaline earth metal salt of a malonic ester and then with an alkyl halide, the reaction product is converted by decarboxylation into the corresponding lactone, which is further reacted by known methods to give the compound XI.The compounds of the formula XI, some of which are novel, can advantageously be used as catalysts for olefin polymerization.

Abstract: The invention is a catalyst system including a monocyclopentadienyl titanium compound and an alumoxane component which is highly productive for polymerizing ethylene and .alpha.-olefins to produce a high molecular weight ethylene-.alpha.-olefin copolymer having a high content of .alpha.-olefin.

Abstract: A process is provided for preparing a transition metal compound of the formula: (RC.sub.5 H.sub.4).sub.2 MX.sub.2, where R is hydrocarbyl or silahydrocarbyl of 1 to 10 carbon atoms, M is titanium or zirconium and X is halogen. The process comprises the steps of:(a) reacting Na(C.sub.5 H.sub.5) with RX, where R and X are as defined above, in an organic solvent so as to form a reaction product mixture which includes RC.sub.5 H.sub.4 and C.sub.5 H.sub.5 ;(b) vacuum stripping the product mixture at ambient temperatures so as to remove substantially all of said C.sub.5 H.sub.5 from said product mixture;(c) deprotonating the RC.sub.5 H.sub.4 ; and(d) adding MX.sub.4, where M and X are as defined above, to the product mixture so as to react the RC.sub.5 H.sub.4 and the MX.sub.4 and form said transition metal compound, the transition metal compound being substantially free of C.sub.5 H.sub.5 containing impurities.

Abstract: Titanocenes of the formula I ##STR1## in which R.sup.1 are cyclopentadienyl.sup..crclbar. groups and R.sup.2 and R.sup.3 are aromatic radicals which are substituted in both ortho-positions by fluorine and, in addition, are substituted by an acyloxy group are suitable as photoinitiators for the photopolymerization of ethylenically unsaturated compounds.

Abstract: Addition polymerization catalysts comprising a derivative of a Group 4-8 metal compound prepared by metal center oxidation.

Abstract: The novel metallocenes of the formula I ##STR1## in which, preferably, M.sup.1 is Zr or Hf, R.sup.1 and R.sup.2 are alkyl or halogen, R.sup.3 and R.sup.4 are hydrogen, R.sup.5 and R.sup.6 are alkyl or haloalkyl, --(CR.sup.8 R.sup.9).sub.m --R.sup.7 --(CR.sup.8 R.sup.9).sub.n -- is a single- or multi-membered chain in which R.sup.7 may also be a (substituted) hetero atom, and m+n is zero or 1, form, together with aluminoxanes as cocatalysts, a very effective catalyst system for the preparation of polyolefins of high molecular weight.

Abstract: A method is provided for preparing preceramic polymers and silicious ceramic materials which derive therefrom. The preceramic polymers are polysiloxanes which are synthesized by catalytically activating Si-H bonds in a hydridosiloxane starting material and replacing the activated hydrogen atoms with non-hydrogen substituents. These preceramic polysiloxanes are pyrolyzed in a selected atmosphere to give the desired ceramic product. Ceramic products which may be prepared by this technique include silica, silicon oxynitride, silicon carbide, and metal silicates.

Abstract: Silicon-bridged transition metal compounds and their use as .alpha.-olefin polymerization catalysts are disclosed. A chiral silicon-bridged metallocene catalyst polymerizes .alpha.-olefins to high isotacity with a minimum of inversions at high rates of catalyst activity. The catalyst is easily made in high yields and readily separated from atactic meso forms.

Abstract: A chiral, stereorigid metallocene compound of the formula I[R.sup.1 R.sup.2 Si(indenyl)2]Y.sup.2 X (I)(me.sup.2 =Ti, Zr or Hf)which is produced as a virtually pure racemate and can be used as a catalyst component for the polymerization of 1-olefins is obtained by reacting a silylindenyl compound of the formula II[R.sup.1 R.sup.2 Si(indenyl).sub.2 ]Me.sub.2.sup.1 (II)(Me.sup.1 =alkali metal)with a titanium, zirconium or hafnium tetrahalide.

Abstract: The invention is a catalyst system including a Group IV B transition metal component and an alumoxane component which may be employed to polymerize olefins to produce a high molecular weight polymer.