Abstract: The invention relates to ruthenium complexes which have a chiral diphosphorus donor ligand and in which the ruthenium has the oxidation state (+11) and the chiral diphosphorus donor ligand has bidentate P—P coordination to the ruthenium. The ruthenium complexes are present in two forms (cationic type A and uncharged type B), are cyclic and have a four- to six-membered ring incorporating the diphosphorus donor ligand. The chiral diphosphorus donor ligands are selected from the group consisting of diphosphines, diphospholanes, diphosphites, diphosphonites and diazaphospholanes. Furthermore, processes for preparing the ruthenium complexes of types A and B, which are based on ligand exchange reactions, are described. The Ru complexes are used as catalysts for homogeneous asymmetric catalysis for preparing organic compounds.

Abstract: The present disclosure relates generally to carbon to carbon coupling processes, and more specifically, to dimerization or trimerization by electrocatalysis of alkenes and alkynes at room temperature.

Abstract: The disclosure provides a dense Cu thin film, a dense CuO thin film and the manufacturing process applied in metallization process of ultra-large scale integration (ULSI), which uses a two-step growth consisting of pre-deposition and annealing to form a dense Cu thin film or a dense CuO thin film. In the process, a copper-containing metal-organic complex is used as precursor and a reducing gas is used as carrier gas. The precursor is carried to a reactive system with a substrate by a carrier gas and pre-deposit a CuO thin film on the substrate under lower temperature. Next, stop supplying the precursor and raise the temperature or offer other energy to anneal the thin film with hydrogen gas or reducing gas, which reduces the CuO thin film to a smooth and dense Cu thin film. Then, choosing oxide containing gas as the react gas obtains the CuO thin film.

Abstract: The invention relates to mixtures of diorganylphosphinic acids and carboxylic acids of the formula [cationn+(phosphinate?)x(carboxylic acid anionz?1/z)y] where n=from 1 to 4 x=from 0.01 to n?0.01 y=n?x z=from 1 to 4, where “cation” means an element of the second main and/or transition group, an element of the third main and/or transition group, an element of the fourth main and/or transition group, an element of the fifth main and/or transition group, an element of the sixth transition group, an element of the seventh transition group, and/or an element of the eighth transition group, “phosphinate” means the anion of diorganylphosphinic acids of the formula where R1 and R2 are identical or different and, independently of one another, are H, C1-C6-alkyl, linear or branched, and/or aryl, and/or hydroxyalkyl, and “carboxylic acid anion” means C1-C18 carboxylic acid anions. The invention also relates to processes for their production, and to their use.

Abstract: Stable rare earth tris (organophosphate) solutions comprise a rare earth tris (organophosphate) and a hydrocarbon solvent. From about 2% to about 10% rare earth element, preferably from about 3% to about 8%, is present in the solutions. The rare earth tris (organophosphate) solutions are stable from precipitation of the rare earth tris (organophosphate) for at least about fifteen (15) days, preferably for at least about twenty (20) days and most preferably at least about thirty (30) days. A process for preparing these solutions is described herein. A stabilizing additive, acid, glycol or mixtures thereof, is utilized to inhibit precipitation. The molar ratios of free acid, glycol and/or water to the rare earth element are controlled to inhibit precipitation.

Abstract: A metallocene compound represented by the following Chemical Formula 1: wherein M is a transition metal of Group 4; Cp denotes a cyclopentadienyl ring unsubstituted or substituted by hydrogen, alkyl, cycloalkyl, aryl, alkenyl, alkylaryl, arylalkyl or arylalkenyl radicals; Qs, which are the same or different, are halogen radicals, alkyl, alkenyl, aryl, alkylaryl, or arylakyl radicals having 1 to 20 carbon atoms, or alkylidene radicals having 1 to 20 carbon atoms; A? is methoxymethyl, t-butoxymethyl, tetrahydropyranyl, tetrahydrofuranyl, 1-ethoxyethyl, 1-methyl-1-methoxyethyl, or t-butyl; and a is an integer of 4 to 8. The metallocene compounds in this invention can be strongly supported on the inorganic support, and the supported catalyst of this invention allows for an olefin polymerization process without any fouling in the reactor, and produces a polymer with better morphology and bulk density.

Abstract: Organometallic reversible addition-fragmentation chain transfer reagents (RAFT reagents), processes of free radical polymerization employing the same and polymers with low polydispersity index obtained thereby. The process includes polymerizing at least one monomer with at least one initiator and at least one organometallic RAFT reagent to obtain polymers having terminal organometallic functional groups with low polydispersity index. In addition, the terminal organometallic functional group may be removed by subjecting the obtained polymer to elimination to provide the corresponding organic polymers.

Abstract: Stable rare earth tris (organophosphate) solutions comprise a rare earth tris (organophosphate) and a hydrocarbon solvent. From about 2% to about 10% rare earth element, preferably from about 3% to about 8%, is present in the solutions. The rare earth tris (organophosphate) solutions are stable from precipitation of the rare earth tris (organophosphate) for at least about fifteen (15) days, preferably for at least about twenty (20) days and most preferably at least about thirty (30) days. A process for preparing these solutions is described herein. A stabilizing additive, acid, glycol or mixtures thereof, is utilized to inhibit precipitation. The molar ratios of free acid, glycol and/or water to the rare earth element are controlled to inhibit precipitation.

Abstract: Disclosed is a new catalyst composition comprising a bimetallic Co—Fe catalyst, optionally complexed with a ligand selected from a N-heterocycle, phosphine, or porphorine ligand, that provides a lower cost alternative for the one step synthesis of 1,3-propanediol (1,3-PDO) from ethylene oxide and synthesis gas. For example, a catalyst containing cobalt carbonyl: iron carbonyl with no ligand, or a catalyst containing a cobalt carbonyl: octaethylporphine iron acetate provide moderate yields of 1,3-PDO in a one step synthesis under mild conditions.

Abstract: A process for the production of an organic phosphorus-containing product, which comprises reacting a phosphorus-containing oxide with an unsaturated hydrocarbon in the presence of a boron-containing compound at a temperature of less than or equal to 50° C.

Abstract: A Bis (cyclopentadienyl) metal complex of a derivative thereof is used as a label in an assay utilizing electrichemiluminescence or fluorescence detection means. The Bis (cyclopentadienyl) metal complex may comprise ferrocene or a derivative thereof which gives rise to a ferricinium ion on electrochemical oxidation.

Abstract: The invention relates to a process for preparing water-soluble organotin catalysts by contacting organotin compounds with polyelectrolytes and, optionally, subsequently removing the water.

Abstract: A process for producing high-purity hydrotalcites by reacting alcohols or alcohol mixtures with at least one or more divalent metal(s) and at least one or more trivalent metal(s) and hydrolyzing the resultant alcoholate mixture with water. The corresponding metal oxides can be produced by calcination.

Abstract: A method of forming a film on a substrate using transition metal or lanthanide complexes. The complexes and methods are particularly suitable for the preparation of semiconductor structures using chemical vapor deposition techniques and systems.

Abstract: Zirconocene compounds with two indenyl ligands linked in the 2 position by means of a two-carbon-atoms divalent bridging group can be suitably used as components of catalysts for the polymerization of olefins. Particularly it is possible to prepare, with high yields, ethylene (co)polymers having low molecular weights and narrow molecular weight distributions, without the need of using considerable amounts of molecular weight regulators, such as hydrogen.

Abstract: Novel tripodal cyclopentadiene derivatives have the formula (I) ##STR1## where E are identical or different and are --N(R)(R), --P(R)(R), --As(R)(R), --Sb(R)(R), --OR, --SR, --SeR, --TeR, where R are identical or different and are each hydrogen, a C.sub.1 -C.sub.20 -carboorganic radical or a C.sub.1 -C.sub.30 -organosilicon radical, or E is a leaving group X andR.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6 are identical or different and are each hydrogen, a C.sub.1 -C.sub.20 -carboorganic radical or a C.sub.1 -C.sub.30 -organosilicon radical,Z is a cyclopentadienyl radical or a substituted cyclopentadienyl structural unit andT is hydrogen, a C.sub.1 -C.sub.20 -carboorganic radical or a C.sub.1 -C.sub.30 -organosilicon radical or a group E--Y--, where E is --N(R)(R), --P(R)(R), --As(R)(R), --Sb(R)(R), --OR, --SR, --SeR, --TeR or a leaving group X, where R are identical or different and are each hydrogen, a C.sub.1 -C.sub.20 -carboorganic radical or a C.sub.1 -C.sub.

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

Abstract: There is provided a method for making a monovalent inorganic anion-intercalated hydrotalcite-like material by first reacting a magnesium-containing powder and a transition alumina powder in a carboxylic acid-free, aqueous suspension to form a meixnerite intermediate. This intermediate is then contacted with a monovalent inorganic anion, in its acid or soluble salt form, to make a hydrotalcite-like material. The latter is then separated from the suspension. Representative materials include a bromide-, chloride-, nitrate- or vanadate-intercalated, hydrotalcite-like material.

Abstract: Bicyclopolyazamacrocyclophosphonic acid compounds are disclosed which may form inert complexes with Gd, Mn or Fe ions. The overall charge of the complex can be varied to alter the in vivo biolocalization. Such complexes can be covalently attached to an antibody, antibody fragment or other biologically active molecule to form conjugates. The complexes and conjugates are useful as contrast agents for diagnostic purposes.

Abstract: There is provided a method for making a polyvalent inorganic anion-intercalated hydrotalcite-like material by first reacting a magnesium-containing powder and a transition alumina powder in a carboxylic acid-free, aqueous suspension to form a meixnerite intermediate. This intermediate is then contacted with a polyvalent inorganic anion, in its acid, acid salt or ammonium salt form, to make a hydrotalcite-like material. The latter is then separated from the suspension. Representative materials include a borate- metatungstate- and paramolybdate-intercalated hydrotalcite-like material.

Abstract: There is provided an improved method for making synthetic hydrotalcite by first reacting a divalent metal compound with a trivalent metal oxide powder in a carboxylic acid-free, aqueous solution or suspension to form an intermediate. This intermediate is then contacted with an anion source such as carbon dioxide; a carbonate-containing compound; an acid or an ammonium salt to form a layered double hydroxide having the formula:A.sub.1-x B.sub.x (OH).sub.2 C.sub.z.mH.sub.2 O, where A represents a divalent metal cation, B represents a trivalent metal cation, C represents a mono- to polyvalent anion, and x, z and m satisfy the following conditions: 0.09<x<0.67; z=x/n, where n=the charge on the anion; and 2>m>0.5. Said layered double hydroxide is typically separated from the suspension by filtering, centrifugation, vacuum dehydration or other known means.

Abstract: There is provided a method for making a divalent inorganic anion-intercalated hydrotalcite-like material by first reacting a magnesium-containing powder and a transition alumina powder in a carboxylic acid-free aqueous suspension to form a meixnerite intermediate. This intermediate is then contacted with a divalent inorganic anion, in its acid, acid salt or ammonium salt form, to make a hydrotalcite-like material. The latter is then separated from the suspension. Representative materials include a sulfate- and metavanadate-intercalated hydrotalcite-like material.

Abstract: There is provided a method for making monovalent organic anion-intercalated hydrotalcite-like materials by first reacting a magnesium-containing powder and a transition alumina powder in a carboxylic acid-free, aqueous suspension to form a meixnerite intermediate. This intermediate is then contacted with a monovalent organic anion to form a hydrotalcite-like material. The latter is then separated from the suspension. Representative materials include a stearate-, acetate- or benzoate-intercalated hydrotalcite-like material.

Abstract: There is provided an improved method for making synthetic hydrotalcite by first reacting powdered magnesium oxide with a high surface area, transition alumina in a solution or suspension to form a meixnerite-like intermediate. This intermediate is then contacted with an anion source such as an acid, and most preferably carbon dioxide, to form the layered double hydroxide which is separated from the suspension by filtering, centrifugation, vacuum dehydration or other known means. On a preferred basis, the transition alumina combined with activated magnesia consists essentially of an rehydratable alumina powder having a surface area of 100 m.sup.2 /g or greater. To make related double hydroxide compounds, still other reactants such as bromides, chlorides, boric acids, or salts thereof, may be substituted for the carbon dioxide gas fed into this suspension.

Abstract: There is provided a method for making a divalent or polyvalent organic anion-intercalated hydrotalcite-like materials by first reacting a magnesium-containing powder and a transition alumina powder in an aqueous suspension to form a meixnerite intermediate. This intermediate is then contacted with a dicarboxylate or polycarboxylate anion to form a hydrotalcite-like material. The latter is then separated from the suspension. Representative materials include an oxalate-, succinate- or terephthalate-intercalated hydrotalcite-like material.

Abstract: Disclosed are bis-phosphine compounds having the general formula ##STR1## wherein: each of A.sup.1, A.sup.2, A.sup.3 and A.sup.4 is an arylene radical wherein (i) each phosphorus atom P is bonded to a ring carbon atom of A.sup.1 and A.sup.2 and to a ring carbon atom of A.sup.3 and A.sup.4, (ii) A.sup.1 and A.sup.2, and A.sup.3 and A.sup.4 are bonded to each other by ring carbon atoms and (iii) each of the residues ##STR2## constitutes a 5-membered ring; each of A.sup.5 and A.sup.6 is an arylene radical wherein A.sup.5 and A.sup.6 are bonded to each other and to residues R.sup.1 --C--R.sup.2 and R.sup.3 --C--R.sup.4 by ring carbon atoms and R.sup.1 --C--R.sup.2 and R.sup.3 --C--R.sup.4 are connected to each other through a chain of 4 carbon atoms; andR.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represents hydrogen or a hydrocarbyl radical containing up to about 8 carbon atoms.

Abstract: Methods of providing an image of the gastrointestinal region of a patient and diagnosing the presence of any tumorous tissue in that region using contrast media comprising a combination of at least one polyphosphorylated aliphatic or polyphosphorylated alicyclic compound and at least one paramagnetic ion, wherein the aliphatic and alicyclic compounds comprise at least five carbon atoms, is described. Also described are diagnostic kits for gastrointestinal imaging which include the subject contrast media.

Abstract: The present invention is predicated on the discovery that Mo(III) containing compounds will react with salts of a 1,1-dithioacid to form Mo.sub.4 S.sub.4 L.sub.6. Accordingly, there is provided a method for preparing compounds of the formula Mo.sub.4 S.sub.4 L.sub.6 wherein L is a 1,1-dithioacid ligand comprising:contacting a Mo(III) containing compound with the salt of a 1,1-dithioacid at temperatures and for a time sufficient to form the Mo.sub.4 S.sub.4 L.sub.6 compound. Preferably, the Mo(III) containing compound is dissolved in an organic solvent and the solution is heated at temperatures above about 25.degree. C. up to the boiling point of the solvent and, preferably, at temperatures in the range of about 25.degree. C. to about 250.degree. C.

Abstract: The present invention provides an improved method for preparing compounds of the formula Mo.sub.4 S.sub.4 L.sub.6 comprising:contacting a compound having the formula Mo.sub.2 S.sub.4 L.sub.2, wherein L is a 1,1-dithioacid ligand, with a reducing agent having a reduction potential sufficient to reduce Mo(V) to lower oxidation states, especially to Mo(III) and Mo(IV), at a temperature and for a time sufficient to form the Mo.sub.4 S.sub.4 L.sub.6 compound. Preferably, the Mo.sub.2 S.sub.4 L.sub.2 compound is dissolved in an organic solvent along with the reducing agent and the solution is heated at temperatures above 25.degree. C., up to the boiling point of the solvent and, more preferably, at temperatures in the range of from about 50.degree. C. to about 250.degree. C.

Abstract: An energy polymerizable composition and process therefore, comprising a cationically polymerizable material and a catalytically effective amount of an ionic salt of an organometallic complex cation as polymerization initiator, said ionic salt of an organometallic complex cation being capable of adding an intermediate strength nucleophile or upon photolysis capable of liberating at least one coordination site, said metal in said organometallic complex cation being selected from elements of Periodic Groups IVB, VB, VIB, VIIB, and VIIIB are disclosed. Certain of the organometallic metallic polymerization initiators are novel cationic salts.

Abstract: Crude organic solutions of N,N-dialkylcarbamoylmethylphosphine oxide compounds can be purified by treatment with a first row transition metal salt to form a complex which can be treated to regenerate a purified solution of the compound. The first row transition metal can be selected from the monobasic acid salts of zinc, for example.

Abstract: A process for preparing single enantiomers of chiral sulphoxides is provided. The process involves (a) reacting an achiral sulphur-containing compound, e.g. a disulphide, with a single enantiomer of a chiral template having the formula T-(CO)-CH.sub.2 R.sup.1, wherein T is suitably (eta.sup.5 -C.sub.5 H.sub.5)Fe(CO)(PPh.sub.3)- (Ph=phenyl) and (b) thereafter stereospecifically oxidizing the sulphur atom with an oxidizing agent. A single enantiomer of the chiral sulphoxide can then be generated by reacting the oxidized product with a carbanion. In a preferred embodiment the reaction mixture is thereafter treated with further achiral sulphide to provide a process which is catalytic on the chiral template.

Abstract: New chemical product, constituted by an organic phosphorus compound of the structure ##STR1## where Q is an N or O atom, T is an alkylene or arylene, possibly carrying substituents, or not existing, while R.sup.1 to R.sup.7, the same or different, are H or aliphatic, cycloaliphatic and/or arylic hydrocarbon radicals, possibly substituted, R.sup.3 not existing when Q is oxygen.This product is used as an intermediate in the preparation of different derivatives of phosphinous acid.

Abstract: A process for treating an organic solution of a partially deactivated solubilized rhodium-tertiary organophosphine complex hydroformylation catalyst with an organic reagent in order to improve the extractability of rhodium therefrom into an aqueous solution containing an ionic organophosphine ligand.

Abstract: Certain novel heavy metal salts of dithiophosphonate derivatives, particularly monoesters, may be prepared inexpensively from hindered phenol compounds and are useful as anti-oxidants for example in lubricants and/or polymer materials.

Abstract: A hydroformylation process including contacting hydroformylation stock in a reaction zone at a temperature of from about 20.degree. C. to about 250.degree. C. and a pressure of from about 15 psig to about 800 psig with hydrogen and carbon monoxide wherein the catalyst comprises rhodium in chemical complex with one or more ligands of the formulae ##STR1## wherein: Z, when present, represents the atoms necessary to form with adjacent carbons on the benzene nucleus a fused divalent ring structure having up to about 20 ring carbons;each ring is either unsubstituted or one or more of the hydrogens thereof is replaced with a substituent R selected independently from alkyl, alkoxy, aryloxy, aryl, aralkyl, alkaryl, alkoxyalkyl, cycloaliphatic, halogen, alkanoyl, alkanoyloxy, alkoxycarbonyl, carboxyl or cyano;each R.sub.1 and R.sub.

Abstract: Complex rhodium compounds containing rhodium in combination with the ligands carbon monoxide and a plurality of triarylphosphines and have the formulae:[(aryl.sub.3 P).sub.2 Rh(CO)(alkylCN)].sub.8-n X.sup.+n M.sub.12 O.sub.40,I[(aryl.sub.3 P).sub.2 Rh(CO)(alkylCN)].sub.9-n X.sup.+n M.sub.12 O.sub.40,II[(aryl.sub.3 P).sub.2 Rh(CO)].sub.8-n X.sup.+n M.sub.12 O.sub.40,III[(aryl.sub.3 P).sub.2 Rh(CO)].sub.9-n X.sup.+n M.sub.12 O.sub.40,IV[(aryl.sub.3 P).sub.2 Rh(CO).sub.3 ].sub.8-n X.sup.+n M.sub.12 O.sub.40,V and[(aryl.sub.3 P).sub.2 Rh(CO).sub.3 ].sub.9-n X.sup.+n M.sub.12 O.sub.40,VIwherein alkyl is lower alkyl (C.sub.1 to C.sub.4), X is a transition element selected from Periodic Table groups IIIA, IVA, VA, or VIII, aryl can be phenyl or phenyl substituted by 1 to 3 lower alkyl (C.sub.1 to C.sub.4) and lower alkoxy (C.sub.1 to C.sub.4) groups, M is molybdenum (Mo) or tungsten (W), and n is an integer having a value 2 to 5.

Abstract: Novel dinuclear and water-soluble rhodium complexes, well suited as hydroformylation catalysts, as are aqueous solutions thereof, have the general formula: ##STR1## in which R and R', which are identical or different, are each a substituted or unsubstituted hydrocarbon radical, with the proviso that R and R' may together form a single divalent radical, TAPS is a sulfonated triarylphosphine ligand, and L is a carbonyl (CO) or a TAPS ligand.

Abstract: This invention relates to heterometallic thiocubane compositions containing the M.sub.2.sup.1 M.sub.2.sup.2 S.sub.4 cluster core and methods of making them wherein M.sup.1 is Re, V, Mo or W and M.sup.2 is Co, Cr, Cu, Ni or Fe but preferably Co. More particularly, the invention relates to compositions of the formula M.sub.2.sup.2 M.sub.2.sup.2 S.sub.4 L.sub.2.sup.1 L.sub.2.sup.2 L.sub.2.sup.3 wherein M.sup.1 and M.sup.2 are as above, L.sup.1 is a bidentate sulfur or nitrogen bearing ligand (most preferably a dialkyldithiocarbamate), L.sup.2 is optional but may be an O, N, P or S-containing monodentate donor ligand, and L.sup.3 may be CO, a monodentate anion ligand such as a halide (preferably C1), mercaptide or alkoxide, or another O, N, P, or S containing monodentate donor ligand. The compositions are suitable for making active hydrotreating catalysts.

Abstract: The present invention is directed to high-coordination transition metal complexes, i.e., those of coordination number seven and above, and the use thereof in the room temperature/atmospheric pressure formation of carbon-carbon bonds via reductive coupling of linear carbon-containing ligands, and methods for the isolation and recovery of the newly formed C.sub.2 containing species.

Abstract: Complex rhodium compounds containing rhodium in combination with the ligands carbon monoxide and a plurality of triarylphosphines and have the formulae:[(aryl.sub.3 P).sub.2 Rh(CO)(alkylCN)].sub.8-n X.sup.+n M.sub.12 O.sub.40, I[(aryl.sub.3 P).sub.2 Rh(CO)(alkylCN)].sub.9-n X.sup.+n M.sub.12 O.sub.40, II[(aryl.sub.3 P).sub.2 Rh(CO)].sub.8-n X.sup.+n M.sub.12 O.sub.40, III[(aryl.sub.3 P).sub.2 Rh(CO)].sub.9-n X.sup.+n M.sub.12 O.sub.40, IV[(aryl.sub.3 P).sub.2 Rh(CO).sub.3 ].sub.8-n X.sup.+n M.sub.12 O.sub.40, and V[(aryl.sub.3 P).sub.2 Rh(CO).sub.3 ].sub.9-n X.sup.+n M.sub.12 O.sub.40, VIwherein alkyl is lower alkyl (C.sub.1 to C.sub.4), X is a transition element selected from Periodic Table groups IIIA, IVA, VA, or VIII, aryl can be phenyl or phenyl substituted by 1 to 3 lower alkyl (C.sub.1 and C.sub.4) and lower alkoxy (C.sub.1 to C.sub.4) groups, M is molybdenum (Mo) or tungsten (W), and n is an integer having a value 2 to 5.

Abstract: Silicone compositions having improved thermal oxidative stability are disclosed. The compositions contain iron acetylacetonate, nickel acetylacetonate, cerium acetylacetonate, alpha,omega-bis(trimethylsiloxy)-polydimethylsiloxanes, and optionally, a carboxylic acid. The compositions show greatly increased gel times at temperatures of, e.g. 275.degree. C.