Abstract: A slurry process for polymerizing ethylene is disclosed. The process comprises polymerizing ethylene in the presence of an ?-olefin, hydrogen, and a catalyst comprising an activator and a supported, dimethylsilyl-bridged bis(indenoindolyl)zirconium complex. The process has high catalyst activity and produces polyethylene having a broad molecular weight distribution.

Abstract: The present invention relates to a catalyst for synthesizing a polypropylene with a wide molecular weight distribution and use of the same. The catalyst comprises magnesium halide, titanium-containing compound, and an organic phosphate type electron donor compound. By the catalyst according to the present invention, a propylene polymer with a wide molecular weight distribution, easily controllable isotacticity and good processing properties can be synthesized.

Abstract: The invention provides a process for producing an olefin polymerization catalyst, comprising an organometallic compound of a transition metal or of an actinide or lanthanide, in the form of solid catalyst particles, comprising forming a liquid/liquid emulsion system which comprises a solution of one or more catalyst components dispersed in a solvent immiscible therewith; and solidifying said dispersed phase to convert said droplets to solid particles comprising the catalyst and optionally recovering said particles.

Abstract: An olefin polymerization catalyst which includes an organometallic compound of the following Formula 1; aluminoxane; and an organic transition metal compound of the following Formula 2: M1R11R2mR3n or R2mR3nM1R11M1R2mR3n??[Formula 1 ] in Formula 1, M1 is selected from the group consisting of Group 2A, 2B and 3A of the Periodic Table, R1 is cyclic hydrocarbyl group of 5 to 30 carbon atoms, R2 and R3 are independently hydrocarbyl group of 1 to 24 carbon atoms, l is an integer of more than 1, m and n are independently an integer of 0 to 2, l+m+n is equal to the valence of M1, Q is a divalent group; M2R4pXq??[Formula 2 ] in Formula 2, M2 is Ti, Zr or Hf; R4 is cyclic hydrocarbyl group of 5 to 30 carbon atoms, X is halogen atom, p is an integer of 0 or 1, q is an integer of 3 or 4, p+q is equal to the valence of metal M2.

Abstract: Process for preparing a supported catalyst for the polymerization and/or copolymerization of olefins which has a chromium content of from 0.01 to 5% by weight, based on the element, which comprises (a) preparing a homogeneous solution comprising an organic or inorganic chromium compound and at least one further organic or inorganic compound of elements selected from among Mg, Ca, Sr, B, Al, Si, P, Bi, Sc, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta, W in a protic or aprotic polar solvent, (b) bringing the solution from a) into contact with a finely divided inorganic support to form a catalyst precursor, (c) if appropriate, removing the solvent from the catalyst precursor and (d) calcining the catalyst precursor at temperatures of from 350 to 950° C., preferably 400 to 900° C., under oxidative conditions.

Abstract: A process for the polymerisation of olefin monomers selected from (a) ethylene, (b) propylene (c) mixtures of ethylene and propylene and (d) mixtures of (a), (b) or (c) with one or more other alpha-olefins is performed in a polymerisation reactor in the presence of a supported polymerisation catalyst characterised in that prior to injection into the reactor said supported polymerisation catalyst in the form of a powder is contacted with an inert hydrocarbon liquid in a quantity sufficient to maintain said catalyst in powder form. The preferred inert hydrocarbon liquid is hexane. The supported polymerisation catalyst is preferably a supported metallocene catalyst. According to the process of the prescrit invention the level of fines associated with the polymer products is reduced in particular the level of fines having a diameter<125 ?m and microfines of diameter<50 ?m.

Abstract: Disclosed are catalyst systems and methods of making the catalyst systems for the polymerization of an olefin containing a solid titanium catalyst component containing an inorganic titanium compound, a magnesium alcohol adduct made from an inorganic magnesium compound and an alcohol, and a porous support having at least one of a certain specific surface area, a certain pore volume, and a certain median particle size. The catalyst system may further contain an organoaluminum compound and optionally an organosilicon compound. Also disclosed are methods of making polyolefins.

Abstract: The present invention provides a new supported catalyst for olefin polymerization prepared by reacting a novel transition metal compound on a cocatalyst-supported support, in which the transition metal compound is coordinated with a monocyclopentadienyl ligand to which an amido-quinoline group is introduced, a method for preparing the same, and a method for preparing a polyolefin using the same. The transition metal catalyst compound used in the present invention is configured such that an amido group is linked in a cyclic form via a phenylene bridge. Thus, a pentagon ring structure of the transition metal compound is stably maintained, so that monomers easily approach the transition metal compound and the reactivity is also high.

Abstract: An electrocatalyst ink composition comprising a liquid vehicle, particles comprising at least one electrocatalyst metal, and at least one copolymer dispersant comprising at least one polyalkylene oxide segment.

Abstract: An improved catalytic composition for oligomerization, in particular dimerization, of monoolefins comprises the product resulting from bringing the following three constituents into contact in any order: a) at least one divalent nickel compound; b) at least one hydrocarbylaluminium dihalide, optionally enriched with an aluminum trihalide; and c) at least one organic Bronsted acid; the catalytic composition being pre-conditioned in a solvent before using it for oligomerization.

Abstract: A process and catalyst for the liquid phase selective hydrogenation of alkynes to alkenes with high selectivity to alkenes relative to alkanes, high alkyne conversion, and sustained catalytic activity comprising a reactant comprising an alkyne and a non-hydrocarbon solvent/absorbent, contacting the reactant stream with a hydrogen-containing stream in the presence of a supported, promoted, Group VIII catalyst, removing the solvent/absorbent, and recovering the alkene product.

Abstract: A promoter can have utility in selective heterogeneous oxidation of arylalkyl hydrocarbons such as, for example, cyclohexyl benzene and/or sec-butyl benzene to form hydroperoxides. The promoter can include the product of contacting a solid support comprising a metal oxide surface and an iron compound. The solid support can include, for example, titanium dioxide and/or an iron oxide such as magnetite and can have magnetic susceptibility. A method for the oxidation of arylalkyl hydrocarbons to form hydroperoxides can include contacting 16 an arylalkyl hydrocarbon with oxygen in the presence of the promoter under catalytic oxidation conditions to form arylalkyl hydroperoxide, which can then be converted to phenol via cleavage 26. The method can include recovery 22 of the promoter from the arylalkyl hydroperoxide and can further include recycling the recovered promoter to the contacting 16. Where the solid support has magnetic susceptibility, the recovery 22 can include magnetic separation of the promoter.

Abstract: Provided are transition metal catalytic systems for preparing ethylene homopolymers or copolymers of ethylene with ?-olefins. More specifically, provided are Group 4 transition metal catalysts, which is characterized in that the catalyst comprises around the Group 4 transition metal a cyclopentadiene derivative, and at least one aryloxide ligand(s) having a fluorenyl group or a derivative thereof (which is ready to be substituted at 9-position) that functions as an electron donor and serves to stabilize the catalytic system by surrounding an oxygen atom that links the ligand to the transition metal at ortho-position, and there is no cross-linkage between the ligands; catalytic systems comprising such transition metal catalyst and aluminoxane cocatalyst or boron compound cocatalyst; and processes for preparing ethylene homopolymers or copolymers of ethylene with ?-olefins by using the same.

Abstract: Improved Ziegler-Natta catalysts and methods of making the improved catalyst are described. The Ziegler-Natta catalyst is formed using a spherical MgCl2-xROH support, where R is a linear, cyclic or branched hydrocarbon unit with 1-10 carbon atoms and where ROH is an alcohol or a mixture of at least two different alcohols and where x has a range of about 1.5 to 6.0, preferably about 2.5 to 4, more preferably about 2.9 to 3.4, and even more preferably 2.95 to 3.35. The Ziegler-Natta catalyst includes a Group 4-8 transition metal and an internal donor. The catalyst has improved activity in olefin polymerization reactions as well as good stereoregularity and hydrogen sensitivity.

Abstract: A supported polymerization catalyst system is prepared by a method comprising the following steps: (i) addition of a cocatalyst to a porous support, (ii) mixing a polymerisation catalyst with a polymerisable monomer, and (iii) contacting together the components resulting from steps (i) and (ii). The porous support is preferably silica and the polymerisation catalyst is preferably a metallocene. The polymerisable monomer is typically 1-hexene and the supported catalyst system provides advantages a slowly decaying activity profile particularly when operating in the gas phase.

Abstract: A transition metal complex of the following formula (1): in which A represents an atom of Group 16 of the periodic table; B1 represents an atom of Group 14 of the periodic table; M1 represents a transition metal atom of Group 4 of the periodic table; Cp1 represents a group having a cyclopentadiene anion backbone; R1, R2, R3, R4, R5 and R6 represent independently of one another a hydrogen atom, a halogen atom, a C1-20 alkyl group optionally substituted with a halogen atom; R7, R8, R9, R10, R11 and R12 represent independently of one another a hydrogen atom, a C1-20 alkyl group optionally substituted with a halogen atom; and a 1,3-diene comprising R7, R8, R9, R10, R11, R12 and 4 carbon atoms coordinates on M1, and the 1,3-diene may be of either a cis or trans form, or a mixed form thereof, although the coordination form is not limited, and the double bonds may be delocalized.

Abstract: The invention relates to a process for the preparation of a metal-organic compound, comprising at least one phosphinimine ligand, characterized in that the HA adduct of a phosphinimine ligand according to formula (1) is contacted with a metal-organic reagent of formula (2) in the presence of 1, respectively 2 equivalents of a base, wherein HA represents an acid, of which H represents its proton and A its conjugate base, with Y?N—H as formula (1), and Mv(L1)k(L2)l(L3)m(L4)nX as formula (2), and wherein Y is a substituted phosphorous atom, and M represents a group 4 or group 5 metal ion, V represents the valency of the metal ion, being 3, 4 or 5 L1, L2, L3, and L4 represent a ligand or a group 17 halogen atom on M and may be equal or different, k, l, m, n=0, 1, 2, 3, 4 with k+l+m+n+1=V, and X represents a group 17 halogen atom.

Abstract: The invention refers to a process for increasing the polymerization activity of a titanium containing catalyst, in particular an olefin polymerization catalyst component in particulate form having an improved high temperature activity and the use thereof in a process for polymerizing olefins.

Abstract: The present invention provides a process for preparing a catalyst useful in gas phase polymerization of olefins wherein the hydrogen response of the catalyst can be improved by using a ketone as the electron donor in the catalyst. The catalyst consists of compounds of Ti, Mg, Al and a ketone preferably supported on an amorphous support.

Abstract: The present invention relates to a transition metal complex represented by the formula (I): wherein M represents a Group 4 transition metal; —Y— represents (a): —C(R1)(R20)-A-, (b): —C(R1)(R20)-A1(R30)—, (c): —C(R1)=A1-, or (d): —C(R1)=A1-A2-R30; A represents a Group 16 element and A1 and A2 each represents a Group 15 element; R1 to R9, R20, and R30 are the same or different and each represents an optionally substituted hydrocarbon group, etc.; and X1 and X2 are the same or different and each represents a hydrogen atom, a halogen atom, an optionally substituted C1-10 alkyl group, etc., and an intermediate product thereof, and a catalyst for olefin polymerization which comprises said transition metal complex as a component.

Abstract: Disclosed herein is a group IV transition metal catalyst for producing an ethylene homopolymer or an ethylene-olefin copolymers, having high catalytic activity, which includes a cyclopentadiene derivative and one or more anionic ligands having an aryl group substituted with an aryl derivative at an ortho-position thereof around a transition metal, the ligands not being crosslinked to each other, a catalyst system including the group IV transition metal catalyst and an aluminoxane cocatalyst or a boron compound cocatalyst, and a method of producing ethylene homopolymers or ethylene-olefin copolymers using the catalyst system.

Abstract: A process for the copolymerization of ethylene and ?-olefins which utilizes a mixed modifier comprised of a conjugated diene and alkoxysilane is disclosed.

Abstract: The invention relates to methods for producing cesium hydroxide solutions during which: cesium-containing ore is disintegrated with sulfuric acid while forming a cesium aluminum sulfate hydrate, which is poorly soluble at low temperatures; the formed cesium alum is separated away in the form of a solution from the solid ore residues; the aluminum is precipitated out of the cesium alum solution while forming a cesium sulfate solution; the formed cesium sulfate solution is reacted with barium hydroxide or stontium hydroxide while forming a cesium hydroxide solution, and; the formed cesium hydroxide solution is concentrated and purified.

Abstract: The present invention discloses a metallocene catalyst system for producing polyolefins comprising: A. a hafnocene-based catalyst component suitable for producing the high molecular weight fraction of the polyolefin; B. one or more metallocene or post-metallocene components different from the component A and suitable for producing the low molecular weight fraction of the polyolefin; C. an activating agent having a low or no coordinating capability.

Abstract: A magnesium titanium olefin polymerization procatalyst is prepared by A) reacting a diorganomagnesium compound with a source of active chlorine, (with the proviso that the amount of chlorine is insufficient to completely convert the diorganomagnesium to magnesium dichloride); then B) removing unreacted diorganomagnesium from the reaction product; then depositing a tetravalent titanium species on the reaction product. This procatalyst is highly active for the solution polymerization of olefins when combined with a cocatalyst.

Abstract: A metallocene compound is represented by the formula (1): AMXn-1 wherein M is a transition metal atom having a coordination number of n selected from Group 3, 4, 5 or 6 of the Periodic Table of Elements, or a lanthanide metal atom, or actinide metal atom; A is a substituted monocyclic or polycyclic arenyl ligand pi-bonded to M, wherein said arenyl ligand includes at least one halogen substituent directly bonded to any sp2 carbon atom at a bondable ring position of the ligand; and the or each X is a univalent anionic ligand, or two X are joined and bound to the metal atom to form a metallocycle ring, or two X are joined to form a chelating ligand, a diene ligand, or an alkylidene ligand.

Abstract: The invention refers to a process for preparing a Group 2 metal/transition metal olefin polymerization catalyst component in particulate form having an improved high temperature activity and the use thereof in a process for polymerizing olefins.

Abstract: Catalyst components, methods of forming catalyst compositions, polymerization processes utilizing the catalyst compositions and polymers formed thereby are described herein. The methods generally include providing a magnesium dialkoxide compound, contacting the magnesium dialkoxide compound with a first agent to form a solution of a reaction product “A1”, contacting the solution of reaction product “A1” with a reducing agent to form a reduced reaction product “A2”, contacting reduced reaction product “A2” with a second agent to form a solid reaction product “A3”, contacting solid reaction product “A3” with a metal halide to form reaction product “B” and contacting reaction product “B” with an organoaluminum compound to form a catalyst component.

Abstract: A solid titanium catalyst component (I) of the present invention is characterized in that it contains titanium, magnesium, halogen, and a cyclic ester compound (a) represented by the following formula (1): wherein n is an integer of 5 to 10; R2 and R3 are each independently COOR1 or R, and at least one of R2 and R3 is COOR1; a single bond (excluding Ca—Ca bonds, and a Ca—Cb bond in the case where R3 is R) in the cyclic backbone may be replaced with a double bond; a plurality of R1's are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms; and a plurality of R's are each independently a hydrogen atom or a substituent, but at least one of R's is not a hydrogen atom. When using this solid titanium catalyst component (I), an olefin polymer having a broad molecular weight distribution can be produced.

Abstract: The invention relates to a process for upgrading hydrocarbonaceous feedstreams by hydroprocessing using bulk bimetallic catalysts. More particularly, the invention relates to a catalytic hydrotreating process for the removal of sulfur and nitrogen from a hydrocarbon feed such as a fuel or a lubricating oil feed. The catalyst is a bulk catalyst comprising a Group VIII metal and a Group VIB metal.

Abstract: A catalyst system capable of producing a cyclic olefin polymer having a polar functional group and a high molecular weight with a high yield in which a catalyst is not deactivated due to polar functional groups of monomers, and a method of producing polymers using the same are provided. The catalyst system for polymerization of olefin according to the present invention has good thermal and chemical stability, and thus, in the method of preparing polyolefin using the catalyst system, the deactivation of a catalyst due to a polar functional group of the monomer can be prevented, and thus a high yield of the cyclic olefin polymer with a high molecular weight can be obtained when a ratio of the catalyst to the monomer is 1:5000, and the removal of a catalyst residue is not required.

Abstract: Substituted ferrocenium compounds comprising at least one pendant oleophilic substituent on at least one of the cyclopentadienyl groups and an inert, compatible, noncoordinating, anion and processes for use thereof as catalyst activators for addition polymerizations or as oxidizing agents for metal complex syntheses.

Abstract: A chlorinated propylene-based polymer of the present invention having a weight average molecular weight (Mw) as measured by gel permeation chromatography (GPC) of 5,000 to 100,000 and a chlorine content of 0.1 to 70% by mass has the following properties: (1) it has a high solubility in a non-aromatic solvent having a low environmental burden even when it has a low degree of chlorination, and (2) it can be inhibited from suffering a decrease in the properties inherent to polypropylenes, such as durability, mechanical properties, appearance and hydrophobicity, by regulating its degree of chlorination at a low value.

Abstract: The present invention relates to a bis-arylaryloxy catalyst system for the production of ethylene homopolymers or copolymers with ?-olefins, which has high catalytic activity. More particularly, it relates to a transition metal catalyst comprising a group-IV transition metal as a central metal, a cyclopentadiene derivative around the central metal, and two aryloxide ligands substituted with aryl derivatives at the ortho-positions, the ligands not being bridged to each other, as well as a catalyst system comprising said catalyst and an aluminoxane co-catalyst or a boron compound co-catalyst, and a method for producing high-molecular-weight ethylene homopolymers or copolymers with ?-olefins using the same.

Abstract: The present invention discloses active oligomerisation or polymerisation catalyst systems based on imino-quinolinol complexes.

Abstract: Ligands, compositions, and metal-ligand complexes that incorporate heterocycle-amine compounds are disclosed that are useful in the catalysis of transformations such as the polymerization of monomers into polymers. The catalyst have high performance characteristics, including higher comonomer incorporation into ethylene/olefin copolymers, where such olefins are for example, 1-octene, propylene or styrene. The catalysts also polymerize propylene to form isotactic polypropylene.

Abstract: Ligands, compositions, and metal-ligand complexes that incorporate heterocycle-amine compounds are disclosed that are useful in the catalysis of transformations such as the polymerization of monomers into polymers. The catalyst have high performance characteristics, including higher comonomer incorporation into ethylene/olefin copolymers, where such olefins are for example, 1-octene, propylene or styrene. The catalysts also polymerize propylene to form isotactic polypropylene.

Abstract: Disclosed are catalyst systems and methods of making the catalyst systems/supports for the polymerization of an olefin containing a solid titanium catalyst component and an antistatic agent. Also disclosed are methods of making a polyolefin involving contacting an olefin with a catalyst system containing an antistatic agent. The use of the antistatic agent added to the catalyst system can improve flowability and/or dispersibility of the catalyst system.

Abstract: The present invention provides a method of producing oligomers of olefins, comprising reacting olefins with a catalyst under oligomerization conditions. The catalyst can be the product of the combination of a chromium compound and a pyridyl amine or a heteroaryl-amine compound. In particular embodiments, the catalyst compound can be used to trimerize or tetramerize ethylene to 1-hexene, 1-octene, or mixtures of 1-hexene and 1-octene.

Abstract: A method comprising contacting a support with one or more chromium-containing compounds and one or more boria precursors to provide a catalyst precursor, and activating the catalyst precursor to provide a polymerization catalyst.

Abstract: The present invention provides a method of producing oligomers of olefins, comprising reacting olefins with a catalyst under oligomerization conditions. The catalyst can be the product of the combination of a chromium compound and a heteroaryl-amine compound. In particular embodiments, the catalyst compound can be used to trimerize or tetramerize ethylene to 1-hexene, 1-octene, or mixtures of 1-hexene and 1-octene.

Abstract: The present invention relates to a process for the meso-selective preparation of ansa-metallocene complexes of the formula (I), which comprises reacting a ligand starting compound of the formula (II) with a transition metal compound of the formula III, where R1, R1 are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms, R2, R2 are identical or different and are each hydrogen or an organic radical having from 1 to 40 carbon atoms, R3 is a bulky organic radical which has at least 3 carbon atoms, is bound to the oxygen atom via a nonaromatic carbon or silicon atom and may be substituted by halogen atoms or further organic radicals having from 1 to 20 carbon atoms and may also contain heteroatoms selected from the group consisting of Si, N, P, O and S, T, T? are identical or different and are each a divalent organic group which has from 1 to 40 carbon atoms and together with the cyclopentadienyl ring forms at least one further saturated or unsaturated, substituted

Abstract: The invention relates to a process for preparing a polymerization catalyst component wherein a solid compound with formula Mg(OR1)xCl2-x wherein x is larger than 0 and smaller than 2, and each R1, independently, represents an alkyl group, said compound being obtained by reacting a Grignard compound with an alkoxy- or aryloxy-containing silane compound, is contacted with at least one activating compound selected from the group formed by internal electron donors and compounds of formula M(OR2)v-w(R3)w, wherein M can be Ti, Zr, Hf, Al or Si, each R2 and R3, independently, represent an alkyl, alkenyl or aryl group, v is the valency of M and w is smaller than v, in the presence of an inert dispersant to give an intermediate reaction product, and wherein the intermediate reaction product is contacted with a halogen-containing Ti-compound. A catalyst system comprising said component shows improved performance in olefin polymerization.

Abstract: This invention relates to the field of olefin polymerization catalyst compositions, and methods for the polymerization and copolymerization of olefins, typically using a supported catalyst composition. In one aspect, this invention encompasses precontacting a metallocene with an olefin or alkyne monomer and an organoaluminum compound, prior to contacting this mixture with the acidic activator-support.

Abstract: Monocyclopentadienyl complexes in which the cyclopentadienyl system is substituted by at least one bridged donor, where the bridge contains at least one atom of group 14 of the Periodic Table and at least one atom of group 15 or 16 of the Periodic Table, and a catalyst system comprising at least one of the monocyclopentadienyl complexes, and also methods of preparing them, the use of the catalyst system for the polymerization or copolymerization of olefins and a process for preparing polyolefins by polymerization or copolymerization of olefins in the presence of the catalyst system and the preparation of the associated cyclopentadienyl system.

Abstract: Provided are a polymerization catalyst composition for ethylene oxide which can give polyethylene oxide having a molecular weight lower than that of the prior art and a relatively narrow molecular weight distribution, and a process for the production of polyethylene oxide by the use of the catalyst composition. The catalyst composition makes it possible to produce polyethylene oxide having a molecular weight ranging from about 20,000 to 200,000 through direct polymerization in a high yield with economic advantage, and is characterized by comprising an organoaluminum compound and at least one member selected from among alkali metal alkoxides and alkali metal hydroxides. According to the process, polyethylene oxide having a molecular weight failing within the above range can be produced by the use of the catalyst composition under the same polymerication conditions as those of the prior art.

Abstract: The invention relates to a process for preparing hydrogenated or partially hydrogenated, racemic ansa-metallocene complexes by reacting bridged or unbridged transition metal complexes with alkali metal compounds or alkaline earth metal compounds, heating the resulting reaction mixture to a temperature in the range from ?78 to 250° C. and at least partially hydrogenating the reaction products in the presence of a suitable catalyst, to the corresponding hydrogenated or partially hydrogenated metallocenes and to their use as catalysts or as a constituent of catalysts for the polymerization of olefinically unsaturated compounds or as reagents or catalysts in stereoselective synthesis.

Abstract: Multiple components are selected, conveyed, and measured in a polymerization system. A control system adjusts the system variables to the desired values. Portions of the components can be fed to a pre-contactor before introduction into the polymerization reactor. The catalyst component concentrations and residence times are tightly controlled in the pre-contactor to affect product properties. The pre-contactor can be a single or multiple combinations of a CSTR or plug flow pre-contactors.

Abstract: A process for the selective hydrogenation of diolefinic compounds to mono-olefinic compounds uses a catalyst composition comprising at least one salt of a transition metal from groups IB, IIB, VB, VIB, VIIB and VIII of the periodic table, at least one ligand and at least one organometallic reducing agent, optionally in the presence of a non-aqueous ionic liquid selected from the group formed by liquid salts with general formula Q+A? (in which Q+ represents a quaternary ammonium and/or quaternary phosphonium and A? represents any anion which can form a liquid salt below 90° C.).

Abstract: Metal complexes, catalyst compositions containing the metal complexes, and processes for making the metal complexes and the catalyst compositions are described for the manufacture of polymers from ethylenically unsaturated addition polymerizable monomers. The metal complexes have chemical structures corresponding to one of the following formulae: (Ia) (Ib) (VII) wherein MI. and MII. are metals; T is nitrogen or phosphorus; P is a carbon, nitrogen or phosphorus atom; groups R1, R2 and R3 may be linked to each other; Y is a divalent bridging group; X, X1, and X2 are anionic ligand groups with certain exceptions; D is a neutral Lewis base ligand; and s, o, k, i, ii, p, m, a, b, c, d, e, t, and y are numbers as further described in the claims.