&pgr;-complex compounds

Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...

Reexamination Certificate

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C526S161000, C526S171000, C526S348600, C526S943000, C502S152000, C502S155000, C556S053000

Reexamination Certificate

active

06433112

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to &pgr; complex compounds of transition metals which possess only one &pgr; ligand (half-sandwich structure) and which have a donor-acceptor bond, the donor group or the acceptor group being bonded to the transition metal. The coordinate bond existing between the donor atom and the acceptor atom produces a (partial) positive charge in the donor group and a (partial) negative charge in the acceptor group:
The invention further relates to a process for the preparation of such &pgr; complex compounds of transition metals and to their use as catalysts in processes for the homopolymerization or copolymerization of monomers.
BACKGROUND OF THE INVENTION
Metallocenes are known as &pgr; complex compounds of transition metals and their use as catalysts in the polymerization of olefins is also known (EP-A 129 368 and the literature cited therein). It is also known from EP-A'368 that metallocenes, in combination with alkylaluminium/water as cocatalysts, are effective systems for the polymerization of ethylene. Thus, for example, methylaluminoxane=MAO is formed from ca. 1 mole of trimethylaluminium and 1 mole of water; other stoichiometric proportions have also already been used successfully (WO 94/20 506). The cyclopentadienyl skeletons of such metallocenes were covalently linked together by a bridge. EP-A 704 461 may be mentioned as an example of the numerous patents and patent applications in this field; the linking group mentioned in said patent is a (substituted) methylene group or ethylene group, a silylene group, a substituted silylene group, a substituted germylene group or a substituted phosphine group. EP-A'461 also designates the bridged metallocenes as polymerization catalysts. &pgr; complex compounds suitable as polymerization catalysts are also already known which have only one &pgr; ligand. Examples which may be mentioned are: EP 416 815, U.S. Pat. Nos. 5,453,410, 5,470,993, WO 91/04257, WO 96/13529 and U.S. Pat. No. 5,453,475. In the half-sandwich structures described therein, bonds to a central transition metal are produced on the one hand by a cyclopentadienyl anion and on the other hand by a heteroatom, these two being covalently bonded together via a bridging group. As a result, such catalysts have a forced, strained geometric structure (CGC=Constrained Geometry Catalysts).
Catalysts of the last-mentioned type are outside the framework of the present invention.
Despite the numerous patents and patent applications in this field, there is still a desire for improved catalysts which are distinguished by special properties and high activity, so that the amount of catalyst remaining in the polymer can be kept small.
SUMMARY OF THE INVENTION
It has now been found that particularly advantageous catalysts can be prepared from &pgr; complex compounds of transition metals which have only one &pgr; ligand and which contain a donor-acceptor bond, there being a coordinate or so-called dative bond between the donor atom and the acceptor atom, which bond is at least formally superimposed by an ionic bond, the donor group or the acceptor group being bonded to the central metal. The &pgr; complex compounds according to the invention embrace at least two partial structures, depending on whether the donor atom D or the acceptor atom A is joined to the only &pgr; ligand.
DETAILED DESCRIPTION OF THE INVENTION
Accordingly, the invention relates to &pgr; complex compounds of transition metals of the formula
in which
&pgr; is a charged or electrically neutral &pgr; system which can be fused to one or two unsaturated or saturated five-membered or six-membered rings, and whose H atoms, in the fused or non-fused form, can be partially or completely replaced with identical or different radicals from the group comprising unbranched or branched C
1
-C
20
-(cyclo)alkyl, C
1
-C
20
-halogeno(cyclo)alkyl, C
2
--C
20
-(cyclo)alkenyl, C
1
-C
20
-(cyclo)alkoxy, C
7
-C
15
-aralkyl and C
6
-C
12
-aryl, or replaced in one or two instances with D or A,
D is a donor atom which, in the case of partial structure (Ia), is a substituent or part of the &pgr; system or is bonded to the &pgr; system via a spacer and, in the case of partial structure (Ib), is bonded to the transition metal,
A is an acceptor atom which, in the case of partial structure (Ia), is bonded to the transition metal and, in the case of partial structure (Ib), is a substituent or part of the &pgr; system or is bonded to the &pgr; system via a spacer,
the bonding of D or A to the transition metal taking place either directly or via a spacer, D and A being linked via a coordinate bond in such a way that the donor atom takes on a (partial) positive charge and the acceptor atom a (partial) negative charge, and it being possible for D and A in turn to carry substituents,
M is a transition metal of subgroup III to VIII of the periodic table of the elements (Mendeleeff), including the lanthanides and actinides, preferably of subgroup III to VI, including the lanthanides, and Ni,
X is one anion equivalent and
n is the number zero, one, two, three or four, depending on the charges of M and &pgr;,
D and A being specifically defined as follows:
i) in formula (Ia):
D is disubstituted N, P, As, Sb or Bi or monosubstituted or disubstituted O, S, Se or Te, bonded to &pgr; via a spacer or directly, and
A is B, Al, Ga or In, bonded to M via a spacer or directly; or
ii) in formula (Ia), D and A together are one of the following groups bonded to &pgr; or M via a spacer or directly:
which represent phosphonium salts, phosphorus ylides, aminophosphonium salts and phosphinimines,
or the corresponding ammonium salts and nitrogen ylides, arsonium salts and arsenic ylides sulfonium salts and sulfur ylides, selenium salts and selenium ylides, the corresponding aminoarsonium salts and arsinimines, aminosulfonium salts and sulfimines, aminoselenium salts and selenimines,
 and the corresponding sulfimine structures; or
iii) in formula (Ib):
D is disubstituted N, P, As, Sb or Bi or monosubstituted or disubstituted O, S, Se or Te, bonded to M via a spacer or directly, and
A is disubstituted Al, Ga or In, bonded to &pgr; via a spacer or directly, or disubstituted B, bonded to &pgr; via a spacer,
R
1
, R
2
, R
3
or R
4
and the expression “substituted” independently of one another are C
1
-C
20
-(cyclo)alkyl, C
1
-C
20
-halogeno(cyclo)alkyl, C
2
-C
20
-(cyclo)alkenyl, C
7
-C
15
-aralkyl, C
6
-C
12
-aryl, C
1
-C
20
-(cyclo)alkoxy, C
7
-C
15
-aralkoxy, C
6
-C
12
-arloxy, indenyl, halogen, 1-thienyl, disubstituted amino, trisubstituted silyl which can be bonded via —CH
2
—, or phenylacetylenyl, and “Spacer” is a divalent sityl, germanyl, amino, phosphino, methylene, ethylene, propylene, disilylethylene or disiloxane group which can be monosubstituted to tetrasubstituted by C
1
-C
4
-alkyl, phenyl or C
4
-C
6
-cycloalkyl, and the element P, N, As, S or Se is bonded to &pgr; via the spacer or directly, a spacer being arranged between A and M in the case where D is part of the &pgr; system, and —C(R
1
)═ also occurring as a spacer in cases i) and ii).
The following, which are listed only by way of example and are not exhaustive, are important structures covered by formulae (Ia) and (Ib):
Preferred structures are those without spacers, with the exception of structures in which D is part of the &pgr; system, which always contain a spacer between A and M. Structures of partial formula (Ia) are also preferred.
The &pgr; complex compounds of transition metals according to the invention, of the above-described type (Ia or Ib) in the context of i) or iii), can be prepared, for example in a manner known to those skilled in the art, in such a way that, in the case of the partial structure of formula (Ia). either a compound of formula (II) is reacted with a compound of formula (III):
and
A—MX
n+1
  (III)
with the elimination of the compound YX (IV),
or a compound of formula (V) is reacted with a compound of formula (VI):
and
MX
n+1
  (VI)
with the elimination of the co

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