Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2001-04-05
2002-07-02
Chang, Ceila (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C526S160000, C526S161000, C502S155000
Reexamination Certificate
active
06414162
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to catalysts useful for olefin polymerization. In particular, the catalysts incorporate dianionic indenoindolyl ligands and at least one Group 3-10 transition or lanthanide metal atom.
BACKGROUND OF THE INVENTION
While Ziegler-Nafta catalysts are a mainstay for polyolefin manufacture, metallocenes and similar catalysts are the industry's future. Metallocenes typically include a transition metal and at least one cyclopentadienyl or substituted cyclopentadienyl ligand. More recently, a number of non-metallocene, single-site catalysts have also been reported. Some of these catalysts replace the cyclopentadienyl groups of metallocenes with one or more heteroatomic ring ligands such as boraaryl (U.S. Pat. No. 5,554,775), indolyl or pyrrolyl (U.S. Pat. No. 5,539,124), or azaborolinyl groups (U.S. Pat. No. 5,902,866).
Organometallic complexes that incorporate one transition metal and at least one indenoindolyl ligand have also been described (see PCT Int. App. WO 99/24446 and U.S. Pat. No. 232,260). These complexes are normally made by reacting a transition metal source (e.g. zirconium tetrachloride) with one or two equivalents of an indenoindolyl monoanion. The monoanion is conveniently made by reacting a suitable precursor with about one equivalent of a potent base, such as n-butyllithium or methylmagnesium bromide.
Deprotonation removes an acidic proton from the methylene carbon of the cyclopentadiene fragment:
The indenoindolyl monoanion is a &pgr;-electron donor ligand that can displace labile anionic groups (e.g., a halide) from a transition metal compound to produce an indenoindolyl metal complex:
In the literature examples, R is usually an alkyl or aryl group. in the examples of PCT Int. Appl. WO 99/24446 in which an indenoindolyl transition metal complex is made, R is almost exclusively methyl or phenyl. In the examples of U.S. Pat. No. 6,232,260, R is methyl (see Examples A and B). The reported complexes are normally combined with an activator, such as methyl alumoxane, and are then used to polymerize olefins such as ethylene, or mixtures of ethylene and other &agr;-olefins.
Missing from the literature is any suggestion to make complexes from indenoindolyl ligand precursors that have a hydrogen atom attached to the indole nitrogen. A unique and potentially valuable attribute of these ligand precursors is their ability to form dianions upon deprotonation with two equivalents of a strong base. Until now, such dianionic ligands have not been incorporated into transition metal complexes.
SUMMARY OF THE INVENTION
In one aspect, the invention is an organometallic complex which comprises at least one Group 3-10 transition or lanthanide metal and at least one dianionic indenoindolyl ligand that is pi- or sigma-bonded to the metal. The invention includes complexes produced from a dianionic indenoindolyl ligand that is generated from a synthetic equivalent. Catalyst systems of the invention comprise the complex and an activator, which is preferably an alkyl alumoxane. Also included is a method which comprises polymerizing an olefin in the presence of a catalyst system of the invention.
Indenoindolyl dianions and their synthetic equivalents are remarkably versatile. As described below, they can be used to produce a diverse assortment of monomeric, dimeric, and even polymeric or zwitterionic complexes that incorporate one or more transition metal atoms or a combination of transition metal and Group 13 atoms. When used with an activator, the complexes are valuable olefin polymerization catalysts.
DETAILED DESCRIPTION OF THE INVENTION
Organometallic complexes useful for catalyst systems of the invention comprise at least one Group 3-10 transition or lanthanide metal atom and at least one dianionic indenoindolyl ligand. Preferred complexes include a Group 4 to 6 transition metal; most preferably, the complex contains a Group 4 metal such as titanium or zirconium.
Dianionic indenoindolyl ligands are produced by reacting two equivalents of a potent base with an indenoindole compound. By “indenoindole compound,” we mean an organic compound that has both indole and indene rings. The five-membered rings from each are fused, i.e., they share two carbon atoms. Preferably, the rings are fused such that the indole nitrogen and the only sp
3
-hybridized carbon on the indenyl ring are “trans” to each other. Such is the case in an indeno[1,2-b] ring system such as:
Suitable ring systems also include those in which the indole nitrogen and the sp
3
-hybridized carbon of the indene are beta to each other, i.e., they are on the same side of the molecule. This is an indeno[2,1-b]indole ring system:
The ring atoms can be unsubstituted or substituted with one or more groups such as alkyl, aryl, aralkyl, halogen, silyl, nitro, dialkylamino, diarylamino, alkoxy, aryloxy, thioether, or the like. Additional fused rings can be present, as long as an indenoindole moiety is present.
When the indenoindole is used to make a dianionic ligand, it must have both an unsubstituted nitrogen (i.e., it has a hydrogen atom attached to nitrogen) and at least one hydrogen atom on the indenyl methylene carbon.
Numbering of indenoindoles follows IUPAC Rule A-22. The molecule is oriented as shown below, and numbering is done clockwise beginning with the ring at the uppermost right of the structure in a manner effective to give the lowest possible number to the heteroatom. Thus, 5,10-dihydroindeno[1,2-b]indole is numbered as follows:
while 5,6-dihydroindeno[2,1-b]indole has the numbering:
For correct nomenclature and numbering of these ring systems, see the Ring System Handbook (1998), a publication of Chemical Abstracts Service, Ring Systems File II: RF 33986-RF 66391 at RF 58952. (Note that indenoindoles are incorrectly numbered in U.S. Pat. No. 6,232,260; more correct numbering appears in PCT Int. Appl. WO 99/24446.
Suitable indenoindole compounds that are precursors to indenoindolyl dianions and their synthetic equivalents include, for example, 5,10-dihydroindeno[1,2-b]indole, 5,6-dihydroindeno[2,1-b]indole, 4,7-dimethyl-5,10-dihydroindeno[1,2-b]indole, 4-tert-butyl-8-methyl-5,10-dihydroindeno[1,2-b]indole, 4,8-dichloro-5,10-dihydroindeno-[1,2-b]indole, 2,7-dimethyl-5,6-dihydroindeno[2,1-b]indole, and the like.
Methods for making indenoindole compounds are well known. Suitable methods are disclosed. for example, in U.S. Pat. No. 6,232,260, the teachings of which are incorporated herein by reference, and references cited therein, including the method of Buu-Hoi and Xuong, J. Chem. Soc. (952) 2225. Suitable procedures also appear in Int. Appl. WO 99/24446.
Indenoindolyl dianions can be generated by deprotonating an indenoindole compound with two equivalents of a strong base. Suitable bases include alkali metals (e.g., sodium or potassium), alkali metal hydrides (sodium hydride, lithium hydride), alkali metal aluminum hydrides (lithium aluminum hydride), alkali metal alkyls (n-butyllithium), Grignard reagents (methyl magnesium bromide, phenyl magnesium chloride), and the like. The deprotonation step is normally performed at or below room temperature, preferably at about room temperature, by combining the indenoindole compound and the deprotonating agent, usually in the presence of one or more dry organic solvents, especially ethers and/or hydrocarbons.
Suitable methods for generating dianionic indenoindolyl ligands (and their synthetic equivalents, such as trimethylsilyl-substituted indenoindoles) are also disclosed by T. Abraham et al. in
Monatsh. Chem
. 120 (1989) 117 and
Tetrahedron
38 (1982) 1019. In a typical method, two equivalents of n-butyllithium are added slowly to an ice-cooled solution of the indenoindole in dry tetrahydrofuran to generate a blood-red solution of the dianion.
The first equivalent of base deprotonates the nitrogen atom and creates a sigma-electron donor center at nitrogen:
Further deprotonation removes the cyclopentadienyl-like proton to genera
Chang Ceila
Equistar Chemicals LP
Schuchardt Jonathan L.
Small Andrea D.
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