Abstract: Derivatized molybdenum-sulfide dimers of the general formula [(C.sub.5 R.sub.5 Mo).sub.2 (.mu.-S).sub.4-x (.mu.-SR).sub.x ].sup.n are utilized in the solid state, incorporated in permselective membranes and in aqueous solution as chemical specific complexing agents in various separation processes.

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: The present invention relates to novel compounds for use as imaging agents. In particular, the present invention relates to paramagnetic metal clusters having oxygen and/or nitrogen containing ligands useful as contrast agents for magnetic resonance imaging (MRI).

Abstract: Disclosed is a process for the preparation of transition metal complexes having monosubstituted cyclopentadienyl ligands of the general formula: ##STR1## in which monomeric cyclopentadiene is reacted with organic halides or pseudohalides, using a mixture of an alkali metal oxide or hydroxide and an alkaline earth metal oxide or hydroxide as metallating agent in glycol diether as solvent, to form the intermediate monosubstituted cyclopentadiene, which in situ is metallated and reacted with a transition metal halide to give the final product.

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: 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: The invention relates to a catalyst to be utilized in the metathesis reactions of olefines, the catalyst comprising an after-treated tungsten complex containing diol ligands and hydrocarbon ligands, which are benzenes substituted with a lower alkyl group. The invention also relates to a method for preparing a heterogenous catalyst to be used in the metathesis reaction of olefines as well as to a metathesis process for the conversion of olefines.

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: Process for the preparation of bridged metallocene catalysts. A substituted or unsubstituted cyclopentadiene is deprotonated in a polar solvent to form a solution of the corresponding anion species. The solution is then cooled to a temperature within the range of about -10.degree. to -30.degree. C. A minor amount of a solution of substituted fulvene in a polar solvent is added to a major quantity of the solution of anionic substituted or unsubstituted cyclopentadiene. The substituted fulvene is present in the solvent to provide a concentration of less than 2 molal. The substituted fulvene is disubstituted on the terminal (6) carbon atom and may be substituted or unsubstituted on the cyclopentadienyl ring. The resulting mixture is warmed to a temperature within the range of about 0.degree. to 25.degree. C. (room temperature) to produce a bridged cyclopentadienyl ligand.

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 transition metal salt and powder of the solid reaction product of the ligand with an alkyllithium are reacted at room temperature in a non-polar hydrocarbon. The metallocene thus obtained has a sufficient purity for subsequent use as catalyst for the polymerization of olefins without further purification.

Abstract: This invention is for a metallocene compound which can be used in a catalyst system to produce hemiisotactic polymer. The compound is a bridged metallocene compound having dissimilar cyclopentadienyl groups and no bi-lateral symmetry. One example of the compound is isopropylidene(3-methylcyclopentadienyl-1-fluorenyl) zirconium dichloride. The catalyst of this invention can be converted to an ionic metallocene catalyst by an ionizing agent, such as methylaluminoxane.The polymer produced with this catalyst is characterized by having an isotactic structure effecting only every other asymmetric carbon atom. In the case of polypropylene, every other methyl group is on the same side of the principal polymer chain as represented by a Fisher projection. The remaining methyl groups can be either on the same side or on the opposite side of the principal polymer chain. The polymer produced with the catalyst of this invention can be used as a plasticizer.

Abstract: A process for making ammonolytic precursors to nitride and carbonitride ceramics. Extreme reaction conditions are not required and the precursor is a powder-like substance that produces ceramics of improved purity and morphology upon pyrolysis.

Abstract: Coatings of Group IIA metals and compounds thereof are formed by chemical vapor deposition, in which a heat decomposable organometallic compound of the formula (I) ##STR1## wherein M is a transition metal of Group VB, VIB, VIIB or VIII, R.sub.1 is a lower alkyl or alkenyl radical containing from 2 to about 6 carbon atoms, R.sub.2 is a hydrogen or lower alkyl or alkenyl radical, n is the valence of M and is an integer from 2 to 4, and p is an integer from 0 to (n-1), is contacted with a heated substrate which is above the decomposition temperature of the organometallic compound. The pure metal is obtained when the compound of the formula I is the sole heat decomposable compound present and deposition is carried out under nonoxidizing conditions. Intermetallic compounds such as manganese telluride can be deposited from a manganese compound of formula I and a heat decomposable tellurium compound under nonoxidizing conditions.

Abstract: The present invention constitutes a class of organometallic complexes which reversibly react with hydrogen to form dihydrides and processes by which these compounds can be utilized. The class includes bimetallic complexes in which two cyclopentadienyl rings are bridged together and also separately .pi.-bonded to two transition metal atoms. The transition metals are believed to bond with the hydrogen in forming the dihydride. Transition metals such as Fe, Mn or Co may be employed in the complexes although Cr constitutes the preferred metal. A multiple number of ancilliary ligands such as CO are bonded to the metal atoms in the complexes. Alkyl groups and the like may be substituted on the cyclopentadienyl rings. These organometallic compounds may be used in absorption/desorption systems and in facilitated transport membrane systems for storing and separating out H.sub.2 from mixed gas streams such as the produce gas from coal gasification processes.

Abstract: The invention provides a metallocene catalyst for use in preparing syndiotactic polyolefins. The catalyst comprises a bridged metallocene in which one of the cyclopentadienyl rings is substituted in a substantially different manner from the other ring. It was discovered that this type of catalyst is highly syndiospecific, and it also produces a polymer with a novel microstructure. The invention further includes the use of one or more of the catalysts in a polymerization process. The catalyst is generally described by the formulaR"(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.m is the same or different and is a hydrocarbyl radicals having 1-20 carbon atoms; R" is a structural bridge between the two Cp rings imparting stereoigidity to the catalyst; Me is a group 4b, 5b, or 6b metal from the Periodic Table of Elements; each Q is a hydrocarbyl radical having 1-20 carbon atoms or is a halogen; 0.ltoreq.k.ltoreq.3; 0.ltoreq.n.

Abstract: The invention relates to a process for the preparation of compounds of formula Ia[R.sup.1 FeR.sup.2' ].sup..sym..sub.q [LQ.sub.m ].sup.q.crclbar.(Ia),wherein R.sup.1 is a .pi.-arene, R.sup.2' is an anion of a .pi.-arene, L is a divalent to heptavalent metal or non-metal, Q is a halogen atom, q is an integer from 1 to 3 and m is an integer corresponding to the valency of L+q, said process comprises reacting an uncharged .pi.-complex of the formula IIIa[(R.sup.2').sub.2 Fe] (IIIa)with a .pi.arene R.sup.1 is in the presence of Al and a Lewis-acid followed by treatment with an acid or a salt of an acid of the anion [LQ.sub.m ].sup.q-, the improvement consisting essentially of using TiCl.sub.4 as a Lewis-acid.

Abstract: Broadly stated, the present invention encompasses tetranuclear sulfide-bridged complexes of Cr(III) having bridging organo-carboxylate ligands. Indeed, in one embodiment, the present invention is directed toward a novel composition of matter having a complex cation of the general formula Cr.sub.4 S(RCO.sub.2).sub.8 (L).sub.4.sup.2+, wherein R represents alkyl groups having from 1 to 12 carbon atoms, L represents a ligand or ligands containing a donor atom selected from oxygen, nitrogen, carbon, and sulfur. In the complex of the present invention, the four Cr(III) atoms are bound to a central tetrahedral sulfur atom. The chromium atoms also are octahedrally coordinated with bridging carboxylates and the ligand molecule. Also, the bridging carboxylates, RCO.sub.2 of the above formula, are the same or different carboxylates.

Abstract: A process for making ammonolytic precursors to nitride and carbonitride ceramics. Extreme reaction conditions are not required and the precursor is a powder-like substance that produces ceramics of improved purity and morphology upon pyrolysis.

Abstract: The present invention relates to novel compounds, vitamin supplements, diet pills, and methods for making the same. The vitamin supplements include one or more phytosterol esters, such as esters of sitosterol or stigmasterol, and/or one or more novel substiuted fructose compounds. The diet pills within the scope of the invention include antitrypsin, and may be combined with the vitamin supplements to provide diet vitamin supplements.

Abstract: Compounds of the formula:M(NR.sup.1)(OR.sup.2).sub.2 (CHR.sup.3)whereinM is molybdenum or tungsten;R.sup.1 and R.sup.2 are alkyl, aryl, aralkyl or halogen-substituted derivatives or silicon-containing analogs thereof;R.sup.3 is an alkyl, aryl, aralkyl or any substituent that results from the initial reaction between the M.dbd.CHR.sup.3 complex and the olefin(s) that is(are) being metathesized; alkyl has 1-20 carbons, aryl has 6-20 carbons and aralkyl h as 7-20 carbons.These compounds are catalysts for the metathesis of ordinary olefins (hydrocarbons) and especially functionalized olefins in the homogeneous phase.

Abstract: Polychromium compounds such as octakis(.mu.-trimethylsilylmethyl) tetrachromium(II) as well as a process to make these new compounds are disclosed. The compounds are useful in the production of, e.g., dual valence chromium catalysts useful in the production of linear low density polyethylene.

Abstract: The present invention relates to novel compounds, vitamin supplements, diet pills, and methods for making the same. The vitamin supplements include one or more phytosterol esters, such as esters of sitosterol or stigmasterol, and/or one or more novel substituted fructose compounds. The diet pills within the scope of the invention include antitrypsin, and may be combined with the vitamin supplements to provide diet vitamin supplements.

Abstract: A boron-containing heterocyclic compound prepared by reacting a primary amine or ammonia with an alkylene oxide or epoxide and then reacting concurrently or subsequently this reaction intermediate with a boric acid. This boron-containing heterocyclic compound may further be reacted with a metal, metalloid or other metal compound and even further contain sulfur, such as a sulfide group.The boron-containing heterocyclic compound provides extreme pressure anti-wear properties when provided in a lubricating composition. The lubricating composition may also comprise anti-oxidants, copper corrosion inhibitors, and lead corrosion inhibitors. The anti-wear properties of a lubricating composition can be enhanced using the borates of the present invention in conjunction with a copper compound.

Abstract: An improved process for the preparation of zero valent bis-arene transition metal compounds comprises reducing bis-arene transition metal (I) compound with a high-electropositive metal in an ether solvent at reflux temperature.