Abstract: The invention relates to an organometalic compound of the formula I ##STR1## where M is a metal atom, L are, independently of one another, identical or different .pi. ligands or other electron donors, T is a tin-containing bridge, Y are identical or different and are each a C.sub.1 -C.sub.20 -hydrocarbon group, an amide group, an alkoxy group or a halogen atom and K=0 or 1.The organometallic compound is suitable as catalyst component for olefin polymerization.

Abstract: The present invention relates to optically active and racemic C.sub.2 -symmetric 2,2'-disubstituted 1,1'-diphosphino-ferrocenes of the formula Ia, to optically active and racemic asymmetric 1',2-disubstituted 1-phosphino-ferrocenes of the formula Ib and to achiral 2,2'-disubstituted 1,1'-diphosphino-ferrocenes of the formula II, to processes for preparing them, especially in accordance with the principle of asymmetric ortho-lithiation, to their use as ligands for transition metal complexes, to transition metal complexes comprising them, and to the use of the transition metal complexes as catalysts, especially in asymmetric syntheses.

Abstract: A trityl perfluorophenyl alumninate such as tris(2,2',2"-nonafluorobiphenyl) fluoroaluminate (PBA.sup.-) and its role as a cocatalyst in metallocene-mediated olefin polymerization is disclosed.

Abstract: Metallocene complexes of the formula I ##STR1## where M is titanium, zirconium, hafnium, vanadium, niobium or tantalum,R.sup.1 and R.sup.4 are as defined in the specificationY is nitrogen, phosphorus, arsenic, antimony or bismuth,Z is oxygen, sulfur, selenium or tellurium,n is an integer from 0 to 10,R.sup.5 is ##STR2## R.sup.11 to R.sup.14 and m are as defined in the specification, and 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## and R.sup.15 to R.sup.21 are as defined in the specification. The complexes are used as catalyst components for polymerizing olefins.

Abstract: In a process for converting the achiral meso form or the racemate of an ansa-metallocene complex or a mixture thereof into one of its enantiomers, the conversion is carried out photochemically in the presence of an enantiomerically pure auxiliary reagent.

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: In-situ process for preparing a bridged metallocene, which comprises reacting a substituted cyclopentadiene A, if desired an unsubstituted or substituted cyclopentadienyl compound B, at least one base, at least one bridging reagent and at least one metal component with one another.

Abstract: A number of layered vanadium oxide crystalline compositions are prepared by simple hydrothermal reactions. Generally, the compositions comprise parallel layers of mixed valence vanadium oxides with guest cations intercalated between the layers. The guest cations may comprise metal coordination complexes with bidentate ligands, monomeric ammonium or diammonium cations, or mixtures of alkali metal cations with monomeric ammonium cation or diammonium cations.

Abstract: The synthesis of new sterically hindered ferrocene bis(phosphonites) of formula I ##STR1## the synthesis of the corresponding transition-metal complexes and the use of these complexes in transition-metal-catalyzed reactions are described.

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 present invention relates to a polynuclear metallocene compound of the formula I ##STR1## a process for their preparation and their use as a catalyst for olefin polymerization.

Abstract: Metallocenes containing aryl-substituted indenyl derivatives as ligands, process for their preparation, and their use as catalysts.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 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.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.degree. and 80.degree. C. In addition, reactor deposits are avoided by means of supported catalyst systems.

Abstract: The present invention relates to a metallocene compound of the formula I which is suitable for olefin polymerization ##STR1## where M is a metal of group IVb, Vb or VIb of the Periodic Table.X are each a hydrogen atom, a halogen atom or a C.sub.1 -C.sub.40 -radical OR.sup.4 or NR.sup.4.sub.2, where R.sup.4 are a C.sub.1 -C.sub.20 hydrocarbon radicalm and p are 1, 2 or 3,n is 1 or 2,L each a .pi. ligand which coordinates to the central atom M,M.sup.2 are each a silicon atom, a germanium atom or a tin atom,R.sup.1 are a C.sub.1 -C.sub.20 -radical,R.sup.2 are a C.sub.1 -C.sub.20 -radical or a .pi. ligand which coordinates to the central atom M,A are each a bidentate C.sub.1 -C.sub.40 -hydrocarbon group,Z are each a boron atom, a silicon atom, a germanium atom or a tin atom,R.sup.3 are each a hydrogen atom or a C.sub.1 -C.sub.20 -radical,o is zero, 1 or 2,Hal are each a halogen atom, andwhere n is 1 if R.sup.2 is a .pi. ligand which coordinates to the central atom M and n is 2 if R.sup.2 is a C.sub.1 -C.sub.

Abstract: Disclosed is a novel process for the synthesis of a metal-containing aluminophosphate having a layered structure and novel optically active metal-containing aluminophosphates useful as enantio-selective catalysts, which comprises:a) slurring an aluminum source with water;b) adding a phosphorus source and slurring;c) allowing the mixture to stand;d) adding an organic additive;e) allowing the mixture to stand;f) adding a cationic transition metal complexg) heating to 80.degree.-250.degree. C. for 20-180 hours wherein the mole ratio of transition metal complex to organic additive is in the range of 0.1-1.0:1.0.

Abstract: A catalyst composition suitable for use in a process for the preparation of polyketones comprising a group VIII metal complex of a phosphonite of formula (I)R.sup.1 R.sup.2 E(OPR.sub.2.sup.3).sub.2.sup.-1 (I)where R.sup.1 and R.sup.2 are independently a halide or a hydrocarbyl.R.sup.3 is an optionally substituted hydrocarbylE is boron, aluminium or gallium.Preferred compositions are ?F.sub.2 B(OPPh.sub.2).sub.2 PdCl!.sub.2 and ?F.sub.2 B(OPPh.sub.2).sub.2 Pd(NCPh).sub.2 !.sup.+ ?BF.sub.4 !.sup.-.

Abstract: Alkoxylation products are prepared by reacting compounds having active hydrogen atoms with C.sub.2 -C.sub.4 -alkylene oxides in the presence of a mixed hydroxide built up of polycations and modified with additives and having the general formula I or II?M(II).sub.1-x M(III).sub.x (OH).sub.2 !A.sub.x/n .multidot.m L(I)?LiAl.sub.2 (OH).sub.6 !A.sub.1/n .multidot.m L (II)whereM(II) is at least one divalent metal ion,M(III) is at least one trivalent metal ion,A is at least one inorganic anion andL is an organic solvent or water,n is the valence of the inorganic anion A or in the case of a plurality of anions A is their mean valence andx can assume a value of from 0.1 to 0.5 andm can assume a value of from 0 to 10,as alkoxylation catalyst, wherein the mixed hydroxide contains additives.

Abstract: The invention relates to an organometallic compound of the formula I, ##STR1## where M is a tetravalent metal, L are, independently of one another, identical or different and are each a .pi. ligand, T are, independently of one another, identical or different and are each a bridge and A are, independently of one another, identical or different and are each a .pi. ligand or another electron donor.

Abstract: A number of layered vanadium oxide crystalline compositions are prepared by simple hydrothermal reactions. Generally, the compositions comprise parallel layers of mixed valence vanadium oxides with guest cations intercalated between the layers. The guest cations may comprise metal coordination complexes with bidentate ligands, monomeric ammonium or diammonium cations, or mixtures of alkali metal cations with monomeric ammonium cation or diammonium cations.

Abstract: The invention relates to new transition metal compounds useful as olefin polymerization catalysts. They are characterized by the formula (V)(E)(W)M(L), which in which M is a transition metal, V, E, and W, is e.g.

Abstract: The present invention relates to a stereorigid metallocene compound containing, as ligands, at least two substituted or unsubstituted cyclopentadienyl groups which are bonded to one another via a monocyclic or polycyclic ring system, where at least one cyclopentadienyl group is fused to the monocyclic or polycyclic ring system, and to a process for the preparation of a cycloolefin copolymer. The cycloolefin copolymers obtained in this way have high tear strengths and are suitable for the production of extrusion parts and injection moldings.

Abstract: The quaternary Zintl material (Et.sub.4 N).sub.4 ?Au(Ag.sub.1-x Au.sub.x).sub.2 Sn.sub.2 Te.sub.9 ! that contains 1-D semiconducting chains composed of four metallic elements is prepared by treating ethylenediamine extracts of a pentanary K--Au--Ag--Sn--Te alloy with Et.sub.4 NI.

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: Polyolefins with a molecular weight distribution M.sub.w /M.sub.n .gtoreq.3.0, which may be monomodal, bimodal or multimodal, can be obtained by polymerization or copolymerization of olefins with a catalyst system consisting of an aluminoxane and a transition metal component (metallocene), in which the transition metal component consists of at least one zirconocene of the formula I and at least one zirconocene of the formula Ia ##STR1## or alternatively of at least 2 zirconocenes of the formula I.

Abstract: Metal complexes useful as olefin polymerization catalysts corresponding to the formula: ##STR1## wherein: L is a delocalized, .pi.-bonded group that is bound to M, containing up to 50 nonhydrogen atoms;M is a metal of Group 3, 4 or the Lanthanide series of the Periodic Table of the Elements;Z is a covalently bound, divalent substituent of up to 50 non-hydrogen atoms having the formula, --(ER.sub.2).sub.m --, wherein E independently each occurrence is carbon, silicon or germanium, R independently each occurrence is selected from the group consisting of C.sub.1-20 hydrocarbyl, and C.sub.1-20 hydrocarbyloxy, with the proviso that in at least one occurrence R is C.sub.

Abstract: A method of forming a layered-perovskite bismuth-strontium-tantalum oxide (SBT) ferroelectric material is performed by dissolving a bismuth compound in a first solvent to form a first solution, mixing a strontium compound and a tantalum compound to form a binary mixture, dissolving the binary mixture in a second solvent to form a second solution, mixing the first solution with the second solution to form a SBT precursor solution, evaporating the first and second solvents to form a SBT precursor material and subsequently sintering said SBT precursor material in the presence of oxygen.

Abstract: Heteropolyoxometallates of tungsten, molybdenum and vanadium with a structurally defined micropore volume, a method of production by means of the hydrothermal reaction of the appropriate metal with an associated oxide, a diamine, phosphoric acid and water, and the use of the novel compounds as catalysts.

Abstract: Metal organic compounds containing both cobalt and nickel bound to boron are effective adhesion promoters for bonding rubber to brass-coated metal used as a reinforcement.

Abstract: Biscyclopentadienyl, Group 4 transition metal complexes containing a conjugated diene ligand group wherein the diene is bound to the transition metal either in the form of .sigma.-complex or a .pi.-complex are readily prepared by reacting in any order:a) a Group 4 metal salt corresponding to the formula M'X.sub.3 or M"X.sub.4, or a Lewis base adduct thereof,b) a conjugated diene, D',c) a reducing agent, andd) a compound of the formula: CpM* or (Cp-Cp)M*n.sub.n, wherein,M' is titanium, zirconium or hafnium in the +3 formal oxidation state;M" is titanium, zirconium or hafnium in the +4 formal oxidation state;X is a halide, C.sub.1-6 hydrocarbyloxy or di(C.sub.1-6 hydrocarbyl)amido group;D' is an uncoordinated diene having the same number of carbons as D and the same substitution pattern as D;M* is a Group 1 or 2 metal cation, a Grignard reagent cation or a tri(C.sub.

Abstract: The present invention relates to an unbridged metallocene compound which is suitable for olefin polymerization.

Abstract: Mixed oxide vanadium/antimony/titanium ammoxidation catalysts, particularly suited for the ammoxidation of alkanes and exhibiting X-ray diffraction spectra which are characteristic of a crystallographic phase of rutile TiO.sub.2, are prepared by (a) dissolving respective soluble compounds of vanadium, of antimony and of titanium in at least one saturated alcohol, (b) contacting the alcoholic solution thus obtained with water and precipitating the mixed oxide therefrom, and (c) separating and calcining the mixed oxide thus precipitated.

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 first metal, an alcohol, and a carboxylic acid are reacted to form a metal alkoxycarboxylate which is then reacted with an alkoxide and/or a carboxylate of a second metal to form a precursor. Alternatively, a metal carboxylate and a metal alkoxide are combined and heated to form a precursor. In either alternative, the precursor includes all or most of the metal-oxygen-metal bonds of a desired metal oxide and a carboxylate ligand. The precursor is applied to a substrate, dried and annealed to form the metal oxide, such as BST. The metal-oxygen-metal bonds in the precursor permit the desired metal oxide to be formed from the precursor in one step, providing excellent thin films suitable for integrated circuits. The carboxylate ligand provides stability to the precursor allowing it to be stored for periods common in large scale manufacturing.

Abstract: Novel metal-organic microporous materials are prepared in solution using mild reaction conditions from a metal or metalloid ion with a ligand containing multidentate functional groups in the presence of a templating agent. The resultant microporous materials are useful in the purification of liquids and gases.

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: Compounds of formula (I) are disclosed: ##STR1## wherein L.sup.1 is a main group atom, L.sup.2 is a neutral ligand, M is a transition element or a metal element of Group 13, 14, 15, or 16 of the Periodic Table, x is the number of coordination sites of M, R.sup.1 is a polymerizable group, R.sup.2, R.sup.3, and R.sup.4 are ligands, and R.sup.5 is an anionic ligand. The compounds or monomers of formula (I) are capable of conversion to polymers by combination with one or more other known monomers, such as methyl methacrylate. Such polymers can then be added as a binder in a paint formulation to make marine antifouling coating compositions. Also described is a method to prevent fouling on surfaces wherein a composition containing a metal complex compound of formula (II): ##STR2## wherein M, x, L.sup.2, n, and R.sup.4 have the same meaning as in formula (I), is applied to the surface susceptible to fouling.

Abstract: Group IVB metal metallocenes of bis(1-methyl fluorenyl) diphenyl silane and bis(1-methyl fluorenyl) dimethyl tin are disclosed, plus their use in the production of polyolefins, including isotactic polypropylene.

Abstract: Compounds useful as catalyst components for olefin polymerization. The compounds comprise derivatives of cyclopentadienyl complexes of the ZR or HF.

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: The invention relates to the use as contrast enhancing agents in medical imaging, especially X-ray imaging, of multinuclear complexes, i.e. complexes, such as those of W202 (U20) 2, in which the complexed entity comprises at least two contrast enhancing atoms.

Abstract: A process for the preparation of polymetallooxanes employing inexpensive metal sources such as sand, alumina, and rutile involves dissolving one or more group IIIa, IVa, IVb metaloxy compounds such as metal oxides, metal hydroxides, or hydrates thereof with a di- or polyhydroxyl functional compound in the presence of an amine or alkanolamine. The polymetallooxane products are anionic, neutral, or mixed neutral/anionic moieties, which, when anionic, contain a metallic counterion (cation) or an ammonium or phosphonium ion. Mixed polymetallooxanes, as well as homo polymetallooxanes which may be prepared by the subject process, are suitable for use in preparing coatings, fibers, powders, ceramics, and glasses while being easily processable and economic to manufacture.

Abstract: Metals are reacted in a first solvent, such as 2-methoxyethanol, to form an initial precursor comprising metal-oxide compounds dissolved in the first solvent. A second solvent, such as xylene, that does not react with the metal is added to the solution and the solution heated to distill away the first solvent and form a final precursor. The final precursor is spin-coated on an integrated circuit substrate then dried and annealed to form a thin film of a metal oxide. For metal oxides including bismuth, the bismuth precursor is added to a cold initial precursor and the final precursor is not heated after the bismuth precursor is added. The second solvent wets the substrate better than the first solvent and has a better viscosity for spin-coating, thus resulting in a denser thin film with fewer imperfections.

Abstract: The invention relates to a new improved process for preparing bridged stereorigid metallocenes via organomagnesium and organotin compounds.

Abstract: Metallocene complexes of the general formula I ##STR1## where the substituents Y, M, x, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.6, R.sup.7, R.sup.8, and R.sup.9 are as described in the disclosure, and ligand systems of the general formula II ##STR2## as intermediates.

Abstract: The present invention relates to polymeric multinary azanes built up from units of the general formula [E(NR.sup.1 R.sup.2).sub.a (NR.sup.3).sub.b/2 ], wherein E may be B,Al,Ga,In,Si,Ge,Ti, Zr, Hf,V,Nb,Ta,Cr,Mo or W and R.sup.1,R.sup.2,R.sup.3 may be H, C.sub.1 -C.sub.6 alkyl, vinyl or phenyl; methods for the preparation of these polymers and their use as precursors for high-performance ceramics.

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 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: 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 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: 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.1 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.1 -C.

Abstract: A precursor is made by mixing a metal alkoxycarboxylate-containing liquid with a 2-ethylhexanoic acid in an effective amount for shelf-stabilizing said liquid by substituting 2-ethylhexanoate ligands for alkoxide ligands, thereby forming a mixture, and heating said mixture to substitute said carboxylate ligands for said alkoxide ligands. Specficially, a barium strontium titanate precursor and a strontium bismuth tantalate precursor are made by combining polyoxyalkylated metal moieties to form a liquid solution in which the metal atoms bond with an oxygen atom in a ligand selected from a ligand group consisting of alkoxides and carboxylates, then then heating the liquid solution.

Abstract: Metallocene complexes of the formula I ##STR1## where M is titanium, zirconium, hafnium, vanadium, niobium or tantalum,X inter alia is fluorine, chlorine, bromine, iodine or hydrogen,R.sup.1 to R.sup.6 inter alia are each hydrogen or C.sub.1 -C.sub.10 -alkyl,Z is silicon, germanium, tin or carbon,Y.sup.1 and Y.sup.2 are each ##STR2## R.sup.9 to R.sup.16 inter alia are each hydrogen or C.sub.1 -C.sub.10 -alkyl, andu, v and w are each an integer from 0 to 7, with the proviso that the sum u+v+w is .gtoreq.2, andcyclopentadienyl compounds of the formula II ##STR3## and cyclopentadienyl compound of the formula III ##STR4## as intermediates.

Abstract: The invention relates to new bridged organotin compounds useful in preparing bridged stereorigid metallocenes via organomagnesium and organotin compounds.