WO1998041530A1

WO1998041530A1 - Transition metal metallacyclopentadienyl compounds

Info

Publication number: WO1998041530A1
Application number: PCT/US1998/004994
Authority: WO
Inventors: John F. Walzer, Jr.
Original assignee: Exxon Chemical Patents Inc.
Priority date: 1997-03-17
Filing date: 1998-03-13
Publication date: 1998-09-24
Also published as: AU6463898A

Abstract

The invention is related to organometallic compounds comprising at least one unsubstituted or substituted Group 14 metallacyclopentadienyl ligand π-bonded to a Group 4-5 metal. The invention organometallic compounds are useful as polymerization catalysts when activated and can be used in coordination polymerization and carbocationic polymerization processes. Use of the invention catalyst to polymerize α-olefins is exemplified.

Description

TITLE : Transition Metal Metallacyclopentadienyl Compounds

TECHNICAL FIELD

This invention relates to catalyst compositions effective for addition reactions of olefinically unsaturated monomers, particularly for polymerization. The catalyst compositions comprise effective catalyst activators and Group 4-5 metallocene compounds wherein at least one cyclopentadienyl ancillary ligand includes a Group 14 heteroatom in place of one of the carbon atoms in the 5 -member aromatic ring.

BACKGROUND OF THE TNVENTTON

Coordination polymerization of olefinically unsaturated monomers is well known and has led to the great proliferation of elastomeric and plastic compositions of matter, such as polyethylene, polypropylene, and ethylene propylene rubber. Early pioneers utilized the early transition metal compounds with such activators as aluminum alkyls, later development extended this work to bulky ligand-containing (e.g., η5- cyclopentadienyl) transition metal compounds ("metallocenes") with activators such as alkyl alumoxanes. Representative work addressing polymer molecular weight effects of substituted mono- and biscyclopentadienyl metallocene compounds is described in EP-A 0 129 368 and its counterpart U.S. patent 5,324,800. Hetero-atom containing monocyclopentadienyl metallocene compounds are described in U.S. patent 5,057,475 and silicon bridged biscyclopentadienyl metallocene catalysts are described in U.S. patent 5,017,714. Recent developments have shown the effectiveness of ionic catalysts comprised of activated metallocene cations stabilized by compatible noncoordinating anions, see for example U.S. patents 5,278,119 and 5,384,299 and WO 92/00333. Each of which is incorporated by reference for purposes of U.S. patent practice. A well known problem with metallocene catalysts is a general tendency to have unfavorable ratios of termination reactions, for example β-hydride elimination, to propagation for the polymer chains prepared with them. Description of hetero-atom containing metallocene compounds wherein the cyclopentadienyl rings have a Group 15 atom substituted for a carbon atom is described in

WO95/04087 and U.S. patent 5,434,116. Substituted bis(phosphoryl) zirconocenes and (cyclopentadienyl) (phosphoryl) zirconocenes are illustrated. Each document illustrates ethylene polymerization.

Methods of increasing the electron donating capability of the cyclopentadienyl ligand have been explored and have generally involved introducing steric bulk as occurs with substitution on the cyclopentadienyl rings, for example, U.S. patent 5,324,800, above. In another example, Stahl in J. Organomet. Chem. 1984, 277,113-125, describes the synthesis of titanium metallocene dihalides with pendant dialkylamino substituents on the cyclopentadienyl rings. Problems can arise in using heteroatom substituents such as nitrogen, oxygen or sulfur in that the heteroatom lone pair may be available for other competitive chemical reactions (i.e., interaction with Lewis acids present in the system) that tend to reduce the electron donation capability of the heteroatom substituent.

Independently, academic researchers have addressed the preparation of Group 14 metalloles as organometallic ligands for transition metals. Metallole chemistry was reviewed in "Group 14 Metalloles 2. Ionic Species and Coordination Compounds" , E. Colomer, et al, Chem. Rev. 1990, 90, 265-282. Group 14 metallacyclopentadienyl compounds of Groups 6 - 10 were said to be a potential source for "the still unknown group 14 η -metallacyclopentadienyl species". T. Don Tilley and co-workers have prepared Group 8 metallacyclopentadienyl compounds as reported in "A Stable η-5 Germacyclopentadienyl Complex: [(η⁵-C₅Me₅)Ru{η5-C₄Me₄GeSi(SiMe₃)₃}]", Angew. Chem. Int. Ed. Engl, 1993, 32, 1744-1745. A similar synthesis is described for Group IV, V and VI transition metal compounds in an abstract for Japanese application 08-245715. These compounds are said to be suitable as olefin polymerization catalysts. Independent assessment of these teachings revealed basic unsuitabilities for the preparation of preferred catalyst compounds. INVENTION DISCLOSURE

This invention is directed to Group 4-5 metallocene compounds suitable as polymerization catalysts characterized by comprising at least one unsubstituted or substituted Group 14 metallacyclopentadienyl ancillary ligand π-bonded to a Group 4-5 metal. In view of unfavorable ratios between polymer chain termination reactions and polymer chain propagation for known metallocenes, as well as the propensity toward debilitating reduction demonstrated by biscyclopentadienyl titanium compounds, significant work was conducted to replace a carbon atom in a cyclopentadienyl ring so as to provide a more highly electron-donating Group 14 metalloid or metal in an analogous ancillary ligand, or portion thereof.

Best Mode and Examples of the Invention

The invention Group 4 catalyst compounds described above can be generically represented by the chemical formula

(1) L^AL^B L^CjMAB ,

A R C where L L L j MAB is the invention transition metal metallocene compound. More specifically, L^A is an unsubstituted or substituted Group 14 metallacyclopentadienyl ancillary ligand π-bonded to M; L can be a member of the class of ancillary ligands defined for L , an unsubstituted or substituted cyclopentadienyl ancillary ligand π-bonded to M, or can be J, a heteroatom ancillary ligand sigma-bonded to M; L j is an optional neutral, non-oxidizing ligand having a dative bond to M (typically i equals 0 to 3); M is a Group 4 transition metal; and, A and B are independently monoanionic labile ligands each having a σ-bond to M which can be broken for abstraction purposes by a suitable activator and into which a polymerizable monomer or macromonomer can insert for coordination polymerization, or are ligands which can be converted to such. For definitional purposes the term "Group 14 metallacyclopentadienyl" means a 5- member ring analogous to a cyclopentadiene ring wherein one carbon atom at any position in the ring has been replaced with a non-carbon Group 14 element. The term excludes cyclopentadienyl rings only containing the non-metallic element carbon, but does include those with silicon since it is a metalloid Group 14 element. Preferably the Group 14 metal or metalloid is germanium or silicon, but tin, or lead can be utilized. The Group 14 metallacyclopentadienyl moiety is analogous to the cyclopentadienyl moiety which possesses a formal charge -1, making it formally a monoanionic ligand. And though cyclopentadienyl rings are typically described as being "et -5" bonded to the transition metal in metallocenes, other forms of π-bonding, etα-3 through etα-4, may additionally be possible with the Group 14 metallacyclopentadienyl ligands of the invention and thus are included within the scope of the invention.

Bismetallacyclopentadienyl Group 4 metal catalyst components of the invention are similar to the Group 4 biscyclopentadienyl compounds well-known in the art. These include those represented by the formula :

wherein:

M is a Group 4 metal, preferably Ti, Zr, or Hf;

L is a Group 14 metallacyclopentadienyl ring which may be substituted with from zero to five substituted groups R when y is zero, and from one to four substituted groups R when y is one; and each substituted group R is, independently, a radical selected from hydrocarbyl, silyl-hydrocarbyl or germyl-hydrocarbyl having from 1 to 30 carbon, silicon or germanium atoms, substituted hydrocarbyl, silyl- hydrocarbyl or germyl-hydrocarbyl radicals as defined wherein one or more hydrogen atoms is replaced by a Cj.₂₀ hydrocarbyl radical, a halogen radical, an amido radical, a phosphido radical, an alkoxy radical, an aryloxy radical or any other radical containing a Lewis acidic or basic functionality; C₁.₂₀ hydrocarbyl-substituted metalloid radicals wherein the metalloid is selected from the Group 14 of the

Periodic Table of Elements; halogen radicals; amido radicals; phosphido radicals; alkoxy radicals; or alkylborido radicals; or, L is a Group 14 metallacyclopentadienyl ring in which at least two adjacent R-groups are joined together and along with the carbon atoms to which they are attached form a fused

rύig system which may be saturated, partially unsaturated or aromatic, and substituted or unsubstituted the substitutions being selected as one or more R group as defined above;

e same, or a different, metallacyclopentadienyl ligand as defined for

L ; or, is a cyclopentadienyl ring which may be substituted with from zero to five substituted groups R when y is zero, and from one to four substituted groups R when y is one; and each substituted group R is, independently, a radical selected from hydrocarbyl, silyl-hydrocarbyl or germyl-hydrocarbyl having from 1 to 30 carbon, silicon or germanium atoms, substituted hydrocarbyl, silyl- hydrocarbyl or germyl-hydrocarbyl radicals as defined wherein one or more hydrogen atoms is replaced by a halogen radical, an amido radical, a phosphido radical, an alkoxy radical, an aryloxy radical or any other radical containing a Lewis acidic or basic functionality;

C_j to C^Q hydrocarbyl-substituted metalloid radicals wherein the metalloid is selected from the Group 14 of the Periodic Table of Elements; halogen radicals; amido radicals; phosphido radicals; alkoxy radicals; or alkylborido radicals; or, L is a cyclopentadienyl ring in which at least two adjacent R-groups are joined together and along with the carbon atoms to which they are attached form a fused

C^ to C2_Q ring system which may be saturated, partially unsaturated or aromatic, and substituted or unsubstituted the substitutions being selected as one or more R group as defined above

each of A and B is independently a labile, monoamonic ligand selected from hydride; substituted or unsubstituted Ci to C30 hydrocarbyl; alkoxide; aryloxide; amide; halide or phosphide; Group 14 organometalloids; or both X's together may form an alkylidene or a cyclometallated hydrocarbyl or any other dianionic ligand;

y is 0 or 1; and when y=l,

Y is a bridging group covalently bonded to both L^A and L^B, in L^A (and L if as defined for L^A) through either the Group 14 metal or metalloid atom or one of the ring carbon atoms, typically comprising at least one Group 13, 14 or 15 element such as carbon, silicon, boron, germanium, nitrogen or phosphorous with additional substituents R as defined above so as to complete the valency of the Group 13, 14 or 15 element(s);

L is an optional neutral Lewis base other than water, such as an olefin, diolefin, alkyne, arene, amine, phosphine, ether or sulfide, e.g., diethylether, tetrahydrofuran, dimethylaniline, aniline, trimethylphosphine, n-butylamine, and the like; and,

i is a number from 0 to 3. Monometallacyclopentadienyl Group 4 metal catalyst components of the invention are similar to the monocyclopentadienyl Group 4 metallocene compounds well-known in the art. These compounds include those represented by the following diagram :

wherein:

each of M, L , A, B, Y, y, L^c and i are defined as above and M is preferably Ti;

J is a Group 15 or 16 heteroatom which may be substituted with one R' group when J is a group 15 element, and y is one, or a group 16 element and y is zero, or with two R' groups when J is a group 15 element and y is zero, or is unsubstituted when J is Group 16 element and y is one; and each substituent group R' is, independently, a radical selected from: hydrocarbyl, silyl- hydrocarbyl or germyl-hydrocarbyl radicals having 1 to 30 carbon, silicon or germanium atoms; substituted hydrocarbyl, silyl- hydrocarbyl or germyl-hydrocarbyl radicals as defined wherein one or more hydrogen atoms is replaced by a C₁.₂₀ hydrocarbyl radical, halogen radical, an amido radical, a phosphido radical, an alkoxy radical, or an aryloxy radical; halogen radicals; amido radicals; phosphido radicals; alkoxy radicals; or alkylborido radicals.

Additionally, such compounds include the reaction species that result from reacting together two of the Group 4 metal compounds described, as is well known and described in the literature for mono- and bisCp compounds.

The Group 4 metallacyclopentadienyl compounds suitable when activated as catalysts for the preparation of coordination polymerization homopolymers and copolymers (where copolymer means comprising at least two different monomers) will have ancillary ligand structures comprising the heteroatom containing Cp ring of the invention and additional ligands equivalent to those well-known in the metallocene art relating to traditional mono- and biscyclopentadienyl Group 4 metallocenes, see the background patents and U.S. patents 5,001,205, 5,055,438, 5,198,401, 5,227,440, 5,264,505, 5,324,800, 5,308,816, and 5,304,614 for specific listings. Selection of metallocene ligands for use to make isotactic or syndiotactic polypropylene, and their syntheses, are well-known in the art, specific reference may be made to both patent literature and academic, see for example Journal of Organmetallic Chemistry 369, 359-370 (1989). Typically those catalysts are stereorigid asymmetric, chiral or bridged chiral metallocenes. See, for example, U.S. patent 4,892,851, U.S. patent 5,017,714, U.S. patent 5,145,819, U.S. patent 5,296,434, U.S. patent 5,278,264, WO-A-93/19103, EP-A2-0 577 581, EP-A1-0 578 838, and documents referred to therein. All documents are incorporated by reference for purposes of U.S. patent practice.

Group 5 metallacyclopentadienyl compounds according to the invention are those wherein a cyclopentadienyl ring-containing monoanionic ancillary ligand is replaced with a Group 14 metallacyclopentadienyl ring-containing monoanionic ancillary ligand according to this invention, which can be defined as for L^A above. The preferred Group 5 metals are vanadium and tantalum. Suitable compounds will be analogs to those known in the art, see for example those in U.S. patents 5,502,124 and 5,504,049. Typically such are analogs to the compounds for Group 4 but wherein one monoanionic ancillary ligand (typically a substituted or unsubstituted cyclopentadienyl ligand or a Group 15 or 16 heteroatom) is replaced with a polyanionic ligand so as to form a four-coordinate compound. These patent documents are incorporated by reference for purposes of U.S. patent practice.

Carbocationic polymerization with ionic metallocene catalyst systems are known in the art as well. See for example "η^-C5Me5TiMe3B(C6F5)3: A Carbocationic Olefin

Polymerization Initiator Masquerading as a Ziegler-Natta Catalyst", Ruhksana, Q., et al, J. Am. Chem. Soc, 1994, 116, 6435-6436, U. S. patent 5,448,001 and WO 95/29940. Using a metallacyclopentadienyl ligand of the invention in place of at least one of the cyclopentadienyl ligands of this art will enable the production of carbocationic metallocene catalysts according to the invention. The teachings of these documents are incorporated by reference for purposes of U.S. patent practice.

Synthetic routes to the precursors of the Group 14 metallacyclopentadienyl ligands of the invention have been described in the literature. A preferred synthetic route to the invention precursors is through metathetical reaction of a group 14 tetrahalide or with a group 14 alkyl or aryl substituted trihalide to produce a group 14 metalole, as described by Fagan et. al. in Fagan, P. J.; Nugent, W. A.; Calabrese, J. C. J. Am. Chem. Soc. 1994, 116, 1880-1889, optionally followed by akylation, and finally by reduction, as described by Dufour et. al. in Dufour, P.; Dubac, J.; Dartiguenave, M.; Dartiguenave, Y. Organometallics 1990, 9, 3001-3003. It will be readily apparent to those skilled in the art that a wide variety of metalloles can be prepared according to the method of Fagan via the use of different alkynes (e.g., 2-butyne, trimethylsilylpropyne, 1,2 bistrimethylsilylacetylene, diphenylacetylene) or diynes (e.g., 2,8-decadiyne). It will additionally be appreciated that unsymmetrical metalloles can be generated using the methodology outlined by Buchwald et. al. in Buchwald, S. L.; Fang, Q. J. Org. Chem. 1989, 54, 2793-7, for the production of benzothiophenes, but substituting a group 14 tetrahalide ( group 14 alkyl or aryl substituted trihalide) for the sulfur dichloride used by Buchwald. It should also be noted that, in contrast to literature reports, e.g., Dufour, P.; Dubac, J.; Dartiguenave, M.; Dartiguenave, Y. Organometallics 1990, 9, 3001-3003, I have synthesized stable alkali metal salts of group 14 metallacyclopentadienide anions which previously had only been reported with the use of sterically bulky ligands. See Freeman, W. P.; Tilley, T. D.; Arnold, F. P.; Rheingold, A. L.; Gantzel, P. K. Angew. Chem. Int. Ed. Engl. 1995, 34, 1887-1890.

The preferred synthetic approach to produce the invention compounds utilizing the aforementioned precursors is not readily apparent based on an examination of synthetic routes to analogous metallocenes. While it might be expected that the reaction of alkali metal salts of group 14 metallacyclopentadienide anions with metal tetrahalides (e.g., ZrCl4) or metallocene trihalides (e.g., Cp*ZrCl3) would yield invention compounds via a salt elimination reaction, this is not the case. While the hydrocarbon soluble product mixtures of these reactions do produce small amounts of polyethylene when activated with methylalumoxane, both the nature of the polymer (multi-modal molecular weight distribution) and the low polymerization activity provide extremely strong evidence that the observed polymerization activity is not due to a well defined single-sited catalyst, rather it is analogous to the polymerization activity obtained when a metal halide such as ZrCl4 is combined with methylalumoxane, and likely due to a variety of transition metal byproducts of the reaction described hereafter. Spectoscopic analysis (via ^H NMR) shows that the primary reaction product of the reaction of group 14 metallacyclopentadienide anions such as l-phenyl-2,3,4,5-tetramethylgermolide with e.g., ZrCU, Cp*ZrCl3, or Cp*TiCl3, do not yield the invention compound, but rather yield mixtures of reduction products of the transition metal with concomitant dimerization of the metallole as shown below:

ZrCl4 + Me4C4(Ph)GeLi > 0.5 Me4C4(Ph)Ge— Ge(Ph)C4Me4 + Zr species

It is therefore necessary to use a synthetic route which avoids this undesirable reduction reaction. One such route which is known in the metallocene art is the reaction of a transition metal tetrakis(dialkylamide) species e.g., Zr(NMe2)4 with the neutral cyclopentadiene, generating a metallocene species via amine elimination. See, Lappert, M.F.; Chandra, G. J Chem. Soc. (A) 1968, 1940-1945. Application of this methodology to group 14 metalloles such as l-phenyl-2,3,4,5-tetramethylgermole does not result in any perceptible reaction, even at elevated temperatures, presumably due to the higher pK of the neutral germole or silole relative to analogous cyclopentadienes. Thus this amine elimination approach does not represent a viable approach to the synthesis of the invention compounds.

In contrast to the aforementioned methods, reaction of the group 14 metallacyclopentadienide anions with group 4 precursors which are suitably electron rich so as to avoid reduction, such as Group IV metallocene bis(alkylamido)monohalides (e.g., Cp*Zr(NR2)2Cl, Cp*Ti(NR2)2Cl, CρTi(NR.2)2Cl, CpZr(NR2)2Cl) yields invention compounds, with no evidence of reduction or dimerization of the group 14 metallacyclopentadienide anion used. The conversion of resulting metallocene bis(dialkylamides) to halides can be accomplished using methods described in the literature, e.g., Diamond, G.M.; Rodewald, S.; Jordan, R.F. Organometallics 1995, 14, 5- 7. While this is the preferred route to synthesis of the invention compounds, it is expected that other approaches which follow the important teaching of avoiding reduction by the metallolide ligand may also be successful, such as attachment of the ligand while the metal is in a lower oxidation state, followed by oxidation at the metal center to produce the desired compound by analogy to Teuben's preparation of Cp*TiCl3, see, Blenkers, J.; de Liefde Meijer, H. J.; Teuben, J. H. J. Organomet. Chem. 1981, 218, 383-393.

The metallacyclopentadienyl activated catalysts according to the invention consists primarily of organometallic compounds wherein the Group 4-5 metals are for the most part in their highest oxidation state, even upon activation.

The following digrams show several non-limiting representative transition metal compounds of the invention, which can be synthesized according to the aforementioned general synthetic routes.

The metallacyclopentadienyl catalyst compounds according to the invention may be activated for polymerization catalysis in any manner sufficient to allow coordination or cationic polymerization. This can be achieved for coordination polymerization when one of the A or B labile ligands can be abstracted and the other will either allow insertion of the unsaturated monomers or will be similarly abstractable for replacement with an A or B that allows insertion of the unsaturated monomer. The traditional activators of metallocene polymerization art are suitable, those typically include Lewis acids such as alumoxane compounds, and ionizing, anion precursor compounds that abstract one non- ancillary, labile ligand so as ionize the Group 4-5 metal center into a cation and provide a counter-balancing noncoordinating anion.

Alkylalumoxanes and modified alkylalumoxanes are suitable as catalyst activators, particularly for the invention metal compounds comprising halide ligands. The alumoxane component useful as catalyst activator typically is an oligomeric aluminum compound represented by the general formula (R"-Al-O)_n, which is a cyclic compound, or R"(R"-

Al-O)_nAlR"2, which is a linear compound. In the general alumoxane formula R" is independently a C_j to CJ_Q alkyl radical, for example, methyl, ethyl, propyl, butyl or pentyl and "n" is an integer from 1 to about 50. Most preferably, R" is methyl and "n" is at least 4. Alumoxanes can be prepared by various procedures known in the art. For example, an aluminum alkyl may be treated with water dissolved in an inert organic solvent, or it may be contacted with a hydrated salt, such as hydrated copper sulfate suspended in an inert organic solvent, to yield an alumoxane. Generally, however prepared, the reaction of an aluminum alkyl with a limited amount of water yields a mixture of the linear and cyclic species of the alumoxane. Methylalumoxane and modified methylalumoxanes are preferred. For further descriptions see, U.S. patents No. 4,665,208, 4,952,540, 5,041,584, 5,091,352, 5,206,199, 5,204,419, 4,874,734, 4,924,018, 4,908,463, 4,968,827, 5,329,032, 5,248,801, 5,235,081, 5,157,137, 5,103,031 and EP 0 561 476 Al, EP 0 279 586 Bl, EP 0 516 476 A, EP 0 594 218 Al and WO 94/10180, each being incorporated by reference for purposes of U.S. patent practice. When the activator is an alumoxane, the preferred transition metal compound to activator molar ratio is from 1 :2000 to 1:10, more preferably from about 1 :500 to 1:10, most preferably from about 1 :250 to 1:100.

The term "noncoordinating anion" is recognized to mean an anion which either does not coordinate to the metal cation or which is only weakly coordinated to it thereby remaining sufficiently labile to be displaced by a neutral Lewis base.

Descriptions of ionic catalysts, those comprising a transition metal cation and a noncoordinating anion, suitable for coordination polymerization appear in the early work in U.S. patents 5,064,802, 5,132,380, 5,198,401, 5,278,119, 5,321,106, 5,347,024, 5,408,017, WO 92/00333 and WO 93/14132. These teach a preferred method of preparation wherein metallocenes are protonated by an anion precursors such that an alkyl/hydride group is abstracted from a transition metal to make it both catiomc and charge-balanced by the noncoordinating anion.

The use of ionizing ionic compounds not containing an active proton but capable of producing both the active metallocene cation and an noncoordinating anion is also known. See, EP-A-0 426 637, EP-A-0 573 403 and U.S. patent 5,387,568. Reactive cations other than the Bronsted acids include ferrocenium, silver, tropylium, triphenylcarbenium and triethylsilylium, or alkali metal or alkaline earth metal cations such as sodium, magnesium or lithium cations. A further class of noncoordinating anion precursors suitable in accordance with this invention are hydrated salts comprising the alkali metal or alkaline earth metal cations and a non-coordinating anion as described above. The hydrated salts can be prepared by reaction of the metal cation-non- coordinating anion salt with water, for example, by hydrolysis of the commercially available or readily synthesized LiB(pfp)₄ which yields [Li*xH2θ] [B(pfp)4], where (pfp) is pentafluorophenyl or perfluorophenyl.

Any metal or metalloid capable of forming a coordination complex which is resistant to degradation by water (or other Bronsted or Lewis Acids) may be used or contained in the anion. Suitable metals include, but are not limited to, aluminum, gold, platinum and the like. Suitable metalloids include, but are not limited to, boron, phosphorus, silicon and the like. The description of non-coordinating anions and precursors thereto of the documents of the foregoing paragraphs are incorporated by reference for purposes of U. S . patent practice.

An additional method of making the ionic catalysts uses ionizing anion pre-cursors which are initially neutral Lewis acids but form the cation and anion upon ionizing reaction with the invention metallocene compounds, for example t (pentafluorophenyl) boron acts to abstract a hydrocarbyl, hydride or silyl ligand to yield a metallocene cation and stabilizing noncoordinating anion, see EP-A-0 427 697 and EP-A-0 520 732. Ionic catalysts for coordination polymerization can also be prepared by oxidation of the metal centers of transition metal compounds by anionic precursors containing metallic oxidizing groups along with the anion groups, see EP-A-0 495 375. The description of noncoordinating anions and precursors thereto of these documents are similarly incorporated by reference for purposes of U.S. patent practice.

When the cation portion of an ionic noncoordinating precursor is a Bronsted acid such as protons or protonated Lewis bases (excluding water), or a reducible Lewis acid such as ferricinium or silver cations, or alkaline metal or alkaline earth metal cations such as those of sodium, magnesium or lithium cations, the transition metal to activator molar ratio may be any ratio, but preferably from about 10:1 to 1:10, more preferably from about 5:1 to 1 :5, even more preferably from about 2:1 to 1 :2 and most preferably from about 1.2: 1 to 1 : 1.2 with the ratio of about 1 : 1 being the most preferred.

Thus the active catalysts of the invention may be an alumoxane complex of, or balanced ionic pair comprising a noncoordinating anion and, a Group 4-5 metal cation comprising at least one Group 14 metallacyclopentadienyl ligand according to the invention. The catalyst complexes of the invention are useful in polymerization of unsaturated monomers conventionally known to be polymerizable under either coordination polymerization conditions or cationic polymerization conditions using metallocenes. Such conditions are well known and include solution polymerization, slurry polymerization, and low, medium and high pressure gas-phase polymerization. The catalyst of the invention may be supported and as such will be particularly useful in the known operating modes employing fixed-bed, moving-bed, fluid-bed, or slurry processes conducted in single, series or parallel reactors.

When the A and B ligands are halogen or alkoxy, e.g., chloride ligands, and are not capable of discrete ionizing abstraction with ionizing, noncoordinating anion pre-cursor compounds, they can be converted to suitable abstractable ligands via known alkylation reactions with organometallic compounds such as lithium or aluminum hydrides or alkyls, alkylalumoxanes, Grignard reagents, etc. See EP-A-0 500 944, EP-A1-0 570 982 and EP- Al-0 612 768. Accordingly, a preferred catalytically active monometallacyclopentadienyl Group 4 transition metal catalyst component is the equivalent metal catalyst cation stabilized and counter-balanced with a noncoordinating anion as derived in any of the foregoing methods.

When using ionic catalysts comprising the invention Group 4-5 metal cations and non-coordinating anions or under conditions where the catalyst and activator are immobilized on a support, the total catalyst system will generally additionally comprise one or more scavenging compounds. The term "scavenging compounds" as used in this application and its claims is meant to include those compounds effective for removing polar impurities from the reaction environment. Impurities can be inadvertently introduced with any of the polymerization reaction components, particularly with solvent, monomer and catalyst feed, and adversely affect catalyst activity and stability. It can result in decreasing or even elimination of catalytic activity, particularly when a metallocene cation-noncoordinating anion pair is the catalyst system. The polar impurities, or catalyst poisons include water, oxygen, metal impurities, etc. Preferably steps are taken before provision of such into the reaction vessel, for example by chemical treatment or careful separation techniques after or during the synthesis or preparation of the various components, but some minor amounts of scavenging compound will still normally be used in the polymerization process itself.

Typically the scavenging compound will be an organometallic compound such as the Group- 13 organometallic compounds of U.S. patents 5,153,157, 5,241,025 and WO-A- 91/09882, WO-A-94/03506, WO-A-93/14132, and that of WO 95/07941. Exemplary compounds include triethyl aluminum, triethyl borane, triisobutyl alurninum, methylalumoxane, isobutyl aluminumoxane, and tri-n-octyl aluminum. Those scavenging compounds having bulky or C8-C20 linear hydrocarbyl substituents covalently bound to the metal or metalloid center being preferred to minimize adverse interaction with the active catalyst. When alumoxane is used as activator, any excess over the amount of metallocene present will act as scavenger compounds and additional scavenging compounds may not be necessary. The amount of scavenging agent to be used with metallocene cation-noncoordinating anion pairs is minimized during polymerization reactions to that amount effective to enhance activity, particularly when it is desired to retain terminal unsaturation since the scavenging agent may tend to act as chain transfer agent resulting in terminal saturation. U.S. patent 5,206,197 describes enhanced carbocationic polymerization wherein cyclopentadienyl-group containing ionic catalyst systems include a metal hydrocarbyl. All documents are incorporated by reference for description of metallocene compounds, ionic activators and useful scavenging compounds.

As indicated above the catalysts according to the invention may be supported for use in gas phase, bulk, slurry polymerization processes, or otherwise as needed. Numerous methods of support are known in the art for copolymerization processes for olefins, particularly for catalysts activated by alumoxanes, any is suitable for the invention process in its broadest scope. See, for example, U.S. patents 5,057,475 and 5,227,440. An example of supported ionic catalysts appears in WO 94/03056. A particularly effective method is that described in co-pending application U.S. Serial Number 08/474,948 filed June 7, 1995, and WO 96/04319. A bulk, or slurry, process utilizing supported, bis- cyclopentadienyl Group 4 metallocenes activated with alumoxane co-catalysts is described as suitable for ethylene-propylene rubber in U.S. patents 5,001,205 and 5,229,478, these processes will additionally be suitable with the catalyst systems of this application. Both inorganic oxide and polymeric supports may be utilized in accordance with the knowledge in the field. See U.S. patents 5,422,325, 5,427,991, 5,498,582, 5,466,649, copending U.S. patent applications 08/265,532 and 08/265,533, both filed 6/24/95, and international publications WO 93/11172 and WO 94/07928. Each of the foregoing documents is incorporated by reference for purposes of U.S. patent practice.

In preferred embodiments of the process for this invention, the catalyst system is employed in liquid phase (solution, slurry, suspension, bulk phase or combinations thereof), in high pressure liquid or supercritical fluid phase, or in gas phase. Each of these processes may be employed in singular, parallel or series reactors. The liquid processes comprise contacting olefin monomers with the above described catalyst system in a suitable diluent or solvent and allowing said monomers to react for a sufficient time to produce the invention copolymers. Hydrocarbyl solvents are suitable, both aliphatic and aromatic, hexane and toluene are preferred. Bulk and slurry processes are typically done by contacting the catalysts with a slurry of liquid monomer or with monomer in a suitable diluent, the catalyst system being supported. Gas phase processes similarly use a supported catalyst and are conducted in any manner known to be suitable for ethylene homopolymers or copolymers prepared by coordination polymerization. Illustrative examples may be found in U.S. patents 4,543,399, 4,588,790, 5,028,670, 5,382,638,

5352,749, 5,436,304, 5,453,471, and 5,463,999, and WO 95/07942. Each is incorporated by reference for purposes of U.S. patent practice.

Generally speaking the polymerization reaction temperature can vary from about -

50°C to about 250°C. Preferably the reaction temperature conditions will be from -20°C to 220°, more preferably below 200°C. The pressure can vary from about 1 mm Hg to 2500 bar, preferably from 0.1 bar to 1600 bar, most preferably from 1.0 to 500 bar. Where lower molecular weight copolymers, e.g., M_n < 10,000, are sought it will be suitable to conduct the reaction processes at temperatures above about 0°C and pressures under 500 bar. The multiboron activators of U.S. patent 5,278,119 can additionally be employed to facilitate the preparation of the low molecular weight copolymers of the invention.

Linear polyethylene, including high and ultra-high molecular weight polyethylenes, including both homo- and copolymers with other alpha-olefin monomers, alpha-olefinic and/or non-conjugated diolefins, for example, C3-C20 olefins, diolefins or cyclic olefins, are produced by adding ethylene, and optionally one or more of the other monomers, to a reaction vessel under low pressure (typically < 50 bar), at a typical temperature of 20-250 °C with the invention catalyst that has been slurred with a solvent, such as heptane or toluene. Heat of polymerization is typically removed by cooling. Gas phase polymerization can be conducted, for example, in a continuous fluid bed gas-phase reactor operated at 2000-3000 kPa and 60-160 °C, using hydrogen as a reaction modifier (100-200 ppm), C4-C8 comonomer feedstream (0.5-1.2 mol%), and C2 feedstream (25-35 mol%). See, U.S. patents 4,543,399, 4,588,790, 5,028,670 and 5,405,922 and 5,462,999, which are incorporated by reference for purposes of U.S. patent practice.

Polypropylene can be prepared essentially as described for linear polyethylene above. The reaction diluent is often comprised of liquid propylene monomer in which the supported ionic catalyst is slurred. Other monomers, typically the lower alpha-olefins (e.g., C2-C10) and/or non-conjugated diolefins, can be introduced into the reaction diluent or solvent when either of polyethylene or polypropylene copolymers are to be prepared. The polymerization reactions for all of linear polyethylene, polypropylene and polyolefin polymers may be conducted in any suitable reactor, for example, in batch, continuous flow, parallel or series reactors. High pressure and loop slurry processes are also suitable.

Levels of comonomer incorporation with ethylene, when producing copolymers, will approximate those identified in the art with the metallocenes of analogous structures, that is when the the structure is similar or the same except for the replacement of a ring carbon atom with germanium or other Group 14 metal or metalloid. Ethylene-a-olefin (including ethylene-cyclic olefin and ethylene-α-olefin-diolefin) elastomers of high molecular weight and low crystallinity can be prepared utilizing the catalysts of the invention under traditional solution polymerization processes or by introducing ethylene gas into a slurry utilizing the a-olefin or cyclic olefin or mixture thereof with other monomers, polymerizable and not, as a polymerization diluent in which the invention catalyst is suspended. Typical ethylene pressures will be between 10 and 1000 psig (69- 6895 kPa) and the polymerization diluent temperature will typically be between -10-160 °C. The process can be carried out in a stirred tank reactor, or more than one operated in series or parallel. See the general disclosure of U.S. patent 5,001,205 for general slurry process conditions and selection of preferred transition metal compounds, which if having halide ligands on the transition metal preferably should be alkylated as discussed above for utility with the ionic catalyst compositions of the invention. For a suitable solution process and analogous, cyclopentadienyl-group containing Group 4 catalyst compounds see U.S. patent application 08/545,973, filed 20 October 1995. All documents are incorporated by reference for description of metallocene compounds, ionic activators and useful scavenging compounds.

Pre-polymerization of the supported catalyst of the invention may also be used for further control of polymer particle morphology in typical slurry or gas phase reaction processes in accordance with conventional teachings. For example such can be accomplished by pre-polymerizing a C2-C6 alpha-olefin for a limited time, for example, ethylene is contacted with the supported catalyst at a temperature of -15 to 30 °C and ethylene pressure of up to about 250 psig (1724 kPa) for 75 min. to obtain a polymeric coating on the support of polyethylene of 30,000-150,000 molecular weight. The pre- polymerized catalyst is then available for use in the polymerization processes referred to above. The use of polymeric resins as a support coating may additionally be utilized, typically by suspending a solid support in dissolved resin of such material as polystyrene with subsequent separation and drying. All documents are incorporated by reference for description of metallocene compounds, ionic activators and useful scavenging compounds.

Other olefinically unsaturated monomers besides those specifically described above may be polymerized using the catalysts according to the invention either by coordination or carbocationic polymerization, for example, styrene, alkyl-substituted styrene, ethylidene norbornene, norbornadiene, dicylopentadiene, cyclopentene, and other olefinically-unsaturated monomers including other cyclic olefins, such as alkyl-substituted norbornenes, isobutylene, isoprene, butadiene, vinyl ethers, vinyl carbazoles, etc. Additionally when bridged structures are used, or other open structures having the ability to incorporate higher alpha-olefin monomers, such as the Group 14 metallacyclopentadienyl catalysts of the invention, alpha-olefinic macromonomers may also be incorporated by copolymerization.

The resulting polymers may be homopolymers or copolymers of more than one monomer, and may be of any of the recognized tacticity forms depending upon the selection of the substitution pattern of the metallocene cation precursor and monomer in accordance with conventional knowledge in the art. See above, addressing isotactic polypropylene. Additionally see U.S. patents 5,066,741 and 5,206,197. These documents are in incorporated by reference for purposes of U.S. patent practice and address the preparation of syndiotactic vinyl aromatic polymers with single η^-cyclopentadienyl metallocene compounds activated by non-coordinating, compatible anions. See also, U.S. patents 5,278,265 and 5,304,523, addressing preparation of isotactic and syndiotactic polypropylene under low temperature conditions using stereo-rigid metallocenes with non- coordinating anions, and U.S. patent 5,324,801, and copending application U.S. Ser. No. 08/472,372 filed June 7, 1995 and published as WO 96/40806, addressing specifically substituted cyclopentadienyl metallocenes useful for polymerizing engineering copolymers of ethylene and cyclic olefins. Each of the above is incorporated by reference for purposes of U.S. patent practice.

Lubricating oil additive compositions can be prepared advantageously when low molecular weight alpha-olefin copolymers having vinyl or vinylidene terminal unsaturation are prepared with the supported catalysts of the invention. See the disclosures of U.S. patent 5,498,809 and international patent applications WO 93/24359, WO 94/19436 and WO 94/13715 and documents listed therein for further information as to low molecular weight alpha-olefin polymers and appropriate substituent patterns on metallocene catalysts. Each is incorporated by reference for purposes of U.S. patent practice.

In a similar manner, but utilizing a catalyst structures suitable for the production of higher molecular weight (10,000 < M_n < 300,000) alpha-olefin/diolefin copolymer having a crystallinity low enough to permit of oil solubility (e.g., < 40% crystallinity), as in copending WO 96/33227 and WO 97/22639, multifunctional viscosity modifying lubricating oil additives can be produced. See the descriptions of lubricating oil modifiers and lubricating oil compositions in U.S. patent nos. 4,749,505, 4,772,406 and WO-A- 93/12148, all incorporated by reference for purposes of U.S. patent practice.

The catalyst compositions of the invention can be used as described above individually for coordination or carbocationic polymerization or can be mixed to prepare polymer blends. By selection of monomers, blends of coordination polymers and blends of carbocationic polymers, or the two together, can be prepared under polymerization conditions analogous to those using individual catalyst compositions. Polymers having increased MWD for improved processing and other traditional benefits available from polymers made with mixed catalyst systems can thus be achieved.

The following examples are presented to illustrate the foregoing discussion. All parts, proportions and percentages are by weight unless otherwise indicated. Although the examples may be directed to certain embodiments of the present invention, they are not to be viewed as limiting the invention in any specific respect. In these examples certain abbreviations are used to facilitate the description. These include : Me = methyl, Ph = phenyl, Cp = cyclopentadienyl, Cp* = pentamethyl cyclopentadienyl, Zr = zirconium, Ge = germanium, and Ti = titanium.

All manipulations were carried out under a nitrogen atmosphere using Schlenk techniques and/or a Vacuum Atmospheres glovebox. Dry, oxygen-free solvents were employed unless otherwise noted. Solution NMR spectra were obtained with a Bruker WM250 instrument at 250.1 MHz (^H). All other reagents were purchased from Aldrich Chemical and used as received.

Example 1 - Preparation of l-phenyl-2,3,4,5-tetramethylgermacyclopentadienyl lithium

Initially 5.00 g (19.3 mmol) l-phenyl-2,3,4,5-tetramethylgermacyclopentadiene (prepared according to Dufour, P. et. al., Organometallics 1990, 9, 3001-3003.) was dissolved in a 250 mL pentane in a 500 mL round bottom flask, to which a 8.00 mL of a 1.6 M solution of butyl lithium in hexane 20.0 mmol) was added dropwise while the reaction was stirred at room temperature. When the addition was complete, 5 mL of diethyl ether was added via syringe. The reaction was allowed to stir for 16 h at room temperature, at which time a solid precipitate was evident. The pale yellow solid product was isolated by filtration and washed with two portions of pentane, and dried in vacuo, to yield 3.25 g (64%) of l-phenyl-2,3,4,5-tetramethylgermacyclopentadienyl lithium. H NMR (THF-d8): d 7.36, 7.33 (d, 2 H, Ph H, 6.90-6.77 (m, 3 H Ph H), 2.02 (s, 6 H,

C4Ge(CH3)4), 1.75 (s, 6 H, C4Ge(CH3)4)-

Example 2 - Preparation of l-phenyl-2,3,4,5-tetramethylgermacyclopentadienyl- pentamethylcyclopentadienyl-bis(dimethylamido)zirconium

1.54 g (4.39 mmol) Cp*Zr(N(CH3)2)2Cl (prepared according to literature methods) was weighed into a 50 mL round bottom flask, along with 1.16 g (4.39 mmol) of l-phenyl-2,3,4,5-tetramethylgermacyclopentadienyl lithium (prepared as per example 1). Toluene was added, and the resulting suspension was refluxed for 40 h. The reaction mixture was allowed to cool to room temperature and the solvent was removed in vacuo. The crude material was extracted with pentane (3 x 15 mL) and filtered through celite to yield a carmel solution which was concentrated to a quarter of its original volume and cooled to -35 °C. The light carmel crystals were isolated by filtration and washed with cold pentane; yield 0.92 g (37 %). 1H NMR (CόDό): d 7.75, 7.73 (d, 2 H, Ph H), 7.34- 7.15(m, 3 H, Ph H), 2.84 (s, 12 H, NCH3), 2.20 (s, 6 H, C4Ge(CH3)4), 2.01 (s, 6 H, C4Ge(CH3)4), 1.88 (s, 15 H, Cp* H).

Example 3 - Slurry-Phase Ethylene-Hexene Polymerization

Polymerization was performed in a 1 -liter autoclave reactor equipped with a mechanical stirrer, an external water jacket for temperature control, a septum inlet and a regulated supply of dry nitrogen and ethylene. The reactor was dried and degassed thoroughly at 115 °C. Toluene (400 cc) was added as a solvent, Methylalumoxane (5.0 ml of a 10 weight percent solution of methylalumoxane in toluene) was added, using a gas tight syringe, and 45 mL of hexene via cannula. The reactor was charged with 200 psig of ethylene at 60 °C. A 10 cc stainless steel bomb was charged with 8.5 mL of a 1.79 millimolar solution of l-phenyl-2,3,4,5-tetramethylgermacyclopentadienyl- pentamethylcyclopentadienyl-bis(dimethylamido)zirconium in toluene and affixed to the reactor with a swagelock fitting. The catalyst was then introduced into the reactor in 1 mL increments. The polymerization was continued for 15 minutes while maintaining the reaction vessel within 2 degrees of 60 °C and 200 psig by constant ethylene flow. The reaction was stopped by rapid cooling and venting. The solid recovered was dried overnight in a nitrogen stream. The yield after drying was 7.6 grams of polymer. The polyethylene had a weight average molecular weight of 350,000, a number average molecular weight of 18,000 and a monomodal molecular weight distribution of 19.5, and contained less than 1% hexene by weight. Specific polymerization activity was calculated by dividing the yield of polymer by the total weight of transition metal contained in the catalyst by the time in hours and by the absolute monomer pressure in atmospheres, i.e.,

specific activity = 7.6 grams PE

1.4 x IO-³ g Zr x 0.25 h x 13.6 atm 1.6 x l0³ g PE/g Zr » h * atm 1.8 x 10⁴ g PE/mmol Zr • h • atm . Example 4 - Preparation of l-phenyl-2,3,4,5-tetramethylgermacyclopentadienyl- cyclopentadienyl-bis(dimethylamido)titanium

30.7 g( 0.125 mol) of CpTi(NMe2)3 (prepared according to Lappert, M.F.; Chandra, G. J. Chem. Soc. (A) 1968, 1940-1945) was dissolved in ca. 125 mL hexanes in a 250 mL round bottom flask. 15.7 mL ( 0.125 mol) of chlorotrimethylsilane was added in one portion via syringe while stirring the solution vigorously. After 16 h the reaction was filtered and 18.75 g of red-orange microcrystalline CpTi(N(CH3)2)2Cl was recovered. The filtrate was cooled to -35 °C overnight, and filtration yielded an additional 8.45 for a combined yield of 27.2 g (93%) of CpTi(N(CH3)2)2Cl. 2.235 g (8.44 mmol) of 1-phenyl- 2,3,4,5-tetramethylgermacyclopentadienyl lithium (prepared as per example 1) was weighed into a 100 mL round bottom flask, along with 40 mL of toluene. The resulting slurry was stirred vigorously at 25 °C, and 2.000 g (8.44 mmol) CρTi(N(CH3)2)2Cl was added dropwise as a toluene solution (10 mL toluene). The resulting suspension was stirred for 30 min, then filtered through a medium frit, and the solvent removed from the filtrate in vacuo. The crude material was triturated with pentane (40 mL) and cooled to - 35 °C. A brick red microcrystalline powder was isolated by filtration and washed with one portion (ca. 5 mL) pentane; yield 1.60 g (41 %). ^H NMR (CόDό): d 7.69, 7.68 (d, 2 H, Ph H), 7.34-7.15(m, 3 H, Ph H), 5.82 (s, 5 H, Cp H), 2.99 (s, 12 H, NCH3), 2.12 (s, 6 H, C4Ge(CH3)4), 1.99 (s, 6 Η, C4Ge(CH3)4).

Claims

CLAIMS:

1. An organometallic compound comprising an unsubstituted or substituted Group 14 metallacyclopentadienyl ligand ╧Ç-bonded to a Group 4 or 5 metal.

2. The compound of Claim 1 wherein the Group 4 or 5 metal is in its highest formal oxidation state.

3. The compound of Claim 1 or 2 comprising two unsubstituted or substituted Group 14 metallacyclopentadienyl ligands ╧Ç-bonded to M.

4. The compound of Claim 1 or 2 additionally comprising an unsubstituted or substituted cyclopentadienyl ligand ╧Ç-bonded to M.

5. The compound of Claims 3 or 4 wherein said ╧Ç-bonded ligands are bridged by a covalent group.

6. The compound of Claim 1 or 2 wherein said Group 14 metallacyclopentadienyl ligand is covalently bridged to a Group 15 or 16 heteroatom which is covalently bonded to M.

7. The composition of Claims 1 -6 wherein said transition metal is Ti.

8. A Group 4-5 metallocene olefin polymerization catalyst compound suitable for activation as a polymerization catalyst characterized by comprising at least one unsubstituted or substituted Group 14 metallacyclopentadienyl ancillary ligand ╧Ç- bonded to a Group 4 or 5 metal.

9. The metallocene compound of claim 8 wherein said metal is a Group 4 metal in its highest formal oxidation state additionally comprising : a) another ancillary ligand selected from the group consisting of a second substituted or unsubstituted Group 14 metallacyclopentadienyl ligand that is the same or different from the Group 14 metallacyclopentadienyl ancillary ligand, a substituted or unsubstituted cyclopentadienyl ligand, and a substituted or unsubstituted Group 15 or 16 heteroatom ligand; and, b) two labile monoanionic ligands which may be the same or different.

10. A polymerization process characterized by comprising contacting one or more monomers polymerizable by coordination polymerization under suitable polymerization conditions with a catalyst composition comprising the metallocene compound of claim 9.

11. The process of Claim 10 wherein said monomers comprise at last one member of the group consisting of ethylene, alpha-olefins, cyclic olefins, non-conjugated diolefins, acetylenically unsaturated monomers, olefinically unsaturated aromatic monomers, and C20-C 1 oo macromonomers.

12. The process of Claim 10 wherein said monomers comprise at last one member of the group consisting of ethylene and C2-C20 alpha-olefins.

13. The process of Claim 10 wherein said monomers comprise propylene.

14. An immobilized catalyst composition comprising a solid porous support and an organometallic compound containing an unsubstituted or substituted Group 14 metallacyclopentadienyl ligand ╧Ç-bonded to a Group 4 or 5 metal.

15. A polymerization process characterized by comprising contacting one or more monomers polymerizable by carbocationic polymerization under suitable polymerization conditions with a catalyst composition comprising an organometallic compound containing an unsubstituted or substituted Group 14 metallacyclopentadienyl ligand ╧Ç-bonded to a Group 4 or 5 metal.