Note: Descriptions are shown in the official language in which they were submitted.
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PR O DUCT~O N OF BFUnDGED ~DETALLO CErnE C O M PLE~S
AND INTERMEDI~ S T~REFQR
llECEINICAL FIELD
This invention relates to a new, efficacious process for producing bridged
metallocene complexes, such as for example dihydrocarbylsilyl-bridged zirconocene
complexes, and ~or producing key intermediates used in the overall synthesis process.
BACKGROUND
The synthesis of certain dihydrocarhylsilyl-bridgedl zirconocene complexes and
their use as polymerization catalyst components have been reported he,elo~ore. See
for example U. Stehling et al., Organometallics 1994, 13, 964-970. Rohrmann et al.
U.S. Pat. No. 5,455,366 issued October 3, 1995, describes multistep processes for
producing a variety of metallocenes having benzo-fused indenyl derivatives as ligands.
These materials are also shown to have utility in the formulation of polymerization
cata1ysts.
While workable, these prior processes are deemed best suited for laboratory-
scale operations. Thus a need exists for a simplified process which can be used to
make desired bridged metallocenes, such as dihydrocarbylsilyl-bridged zirconocene
complexes, in acceptable yields in large scale production facilities. One of the key
steps in any such process is the interaction between a protonated bridged ligand and
a metal tetrahalide salt to form the desired bridged metallocene. Unfortunately, this
reaction tends to be tedious, difficult and time-con~nming.
SUM~IARY OF T~; INVENTION
This invention provides, inter alia, a new process for producing bridged
metallocene compounds -- such as are described in the foregoing Rohrmann et al.
patent -- which is both efficacious and of promising commercial utility in plant-sized
operations.
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One of the key steps of the process involves converting a d~lJroLonated silicon-, germ~nillm- or tin-cont~ining ligand into the metallocene. Preferably, and in
accordance with an embodiment of the invention, this is accomplished to great
advantage by adding a ~ min~ adduct of a Group IV, V, or VI metal tetrahalide toS a solution or slurry formed from a d~LnoLollaled silicon-, germ~nillm- or tin-
cont~ining ligand and an organic liquid medium so as to form a metallocene. As will
be seen hereinafter, significant advantages can be realized by conducting this step in
this manner.
The overall process of the invention, which con~titl~tes another embodiment
of this invention, involves the direct conversion of benzoindanones to benzoindanols
which, without isolation, are converted to benzoindenes. Thereupon the benzoindenes
are bridged by depl~)lolla~illg the benzoindenes with a strong base such as butyllithium
and reacting the resultant deprotonated product with a suitable silicon-, germ~nillm-
or tin-cont~ining bridging reactant such as dichlorodimethylsilane. The resultant
bridged product is d~l,rot~nal~d with a strong base such as butyllithium and reacted
with a suitable Group IV, V, or VI metal-cont~ining reactant such as ZrC14 to provide
a silicon-, germ~nillm- or tin-bridged Group IV, V, or Vl metal complex, such as a
dihydloc~bylsilyl-bridged zirconocene complex. In this embodiment, this last step
can be conducted in various ways but preferably is conducted by adding a ~ minf~adduct of a Group IV, V, or VI metal tetrahalide to a solution or slurry formed from
a deprotonated silicon-, germanium- or tin-cont~inin~ ligand and an organic liquid
medium so as to form a metallocene.
Unlike the Rohrmann et al. procedures, the overall processes of this invention
involve the direct conversion of benzoindanones to benzoindanols which, without
2~ isolation, in turn are converted to benzoindenes. Thereupon the benzoindenes are
bridged by deprotonating the benzoindenes with a strong base such as butyllithium
and reacting the resultant deprotonated product with a suitable silicon-, germanium-
or tin-cont~ining bridging reactant. The resultant bridged product so formed is then
deprotonated with a strong base such as butyllithium and reacted with a suitable
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C~roup IV, V, or ~I (formerly known as Groups IVb, Vb and V~b) metal-cont~ining
reactant to provide a silicon-, germanium- or tin-bridged Group IV, V,.or Vl metal
complex, such as a dihydrocarbyisilyl-bridged zirconocene complex. The inventionthus provides, inter alia, a strai~htrolwald commercially feasible sequence of
operations. Moreover, the initial benzoindanones used in the practice of such
sequence can be formed readily and in high yield by reaction of a 2-haloacyl halide
with naphthalenes ul~ub~LituL~d in at least the 1- and 2-positions. This reaction
normally produces a mixture of two isomers, namely a 4,5-benzoindan-1-one as themajor isomer and a 4,5-benzoindan-3-one as the minor isomer. These isomers can,
if desired, be separated from each other by known procedures. Thus unless expressly
stated otherwise, the term 4,5-benzoindanone as used herein refers to at least one 4,5-
benzoindan-1-one or at least one 4,5-benzoindan-3-one, or a mixture of at least one
4,5-benzoindan-1-one and at least one 4,5-benzoindan-3-one. Similarly depending on
the isomeric m~ nr of the initial 4,5-benzoindanone(s), the conversion of a 4,5-benzoindanone to a 4,5-benzoindanol can form one or more 4,5-benzoindan-1-ols orone or more 4,5-benzoindan-3-ols, or a mixture of one or more 4,5-benzoindan-1-ols
and one or more 4,5-benzoindan-3-ols. Thus unless expressly stated otherwise, the
term 4,5-benzoindanol as used herein refers to at least one 4,5-benzoindan-1-ol or at
least one 4,5-benzoindan-3-ol, or a mixture of at least one 4,5-benzoindan-1-ol and
at least one 4,5-benzoindan-3-ol.
The above and other embodiments will become still further al)~e,-l &om the
ensuing description and appended clairns.
FURTHER DETAILED DESCRIPTION OF THE INVENTI01N
In one of its embodiments this invention provides a process of forming a 4,5-
benzoindanol which comprises mixing together at least one of each of the following:
(a) a 4,5-benzoindanone, (b) an alkali or ~Ik~line earth metal borohydride or alkali
or alkaline earth metal ahlminllm hydride, and (c) a hydroxyl-cont~ining compound
capable of interacting with (b) to serve as a hydrogen source, such that a 4,5-benzoin-
danol is formed. Such borohydride or ah~minllm hydride reductions of the carbonyl
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group can be con-luct~-d with high selectivity and in good yields. The operation is
preferably conducted in a liquid ether reaction medium such as tetrahydrofuran and
alkyltetrahydrofurans .
The preferred 4,5-~enzoindanones for use in the process are 4,5-benzoindan~
ones or mixtures of a major molar proportion of one or more 4,5-benzoindan-1-ones
and a minor molar proportion of one or more 4,5-benzoindan-3-ones, such as for
example a mixture of about 90 mol % of a 4,5-benzoindan-1-one and about 10 mol
% of a 4,5-benzoindan-3-one.
Sodium borohydride is the p.ere-led reducing agent, but use can be made of
other compounds such as sodium aluminum tetrahydride, sodium all-mimlm
hexahydride, and their lithium or potassium analogs. Generally speaking, the alkali
- metal derivatives are preferred over the alkaline earth compounds, and as compared
to the hexahydrides, the tetrahydrides are the more p~e-~ed reagents, especially the
borohydrides. Such more preferred reagents may thus be depicted by the formula
AMHx(OR)y wherein A is an alkali metal, M is boron or aluminllm, R is h~dl.~c~ul,yl,
x is an integer in the range of 2 to 4, and y is an integer in the range of 0 to 2, the
sum of x and y being 4. Most preferably y is zero and ~ is boron.
The hydroxyl-cont~ining component used in the reaction as a source of
hydrogen is either water or a suitable hydroxyorganic compound such as an alcohol,
a polyol, or a phenol. Water or lower alkanols or mixtures thereof are preferred.
The 4,5-benzoindanones used in this reaction are illustrated by formula (A)
below which for convenience depicts the 4,5-benzoindan-1-ones. The 4,5-benzoin-
dan-3-ones have the same formula except that the keto functionality is in the 3-position of the 5-membered ring instead of the 1-position as shown.
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5 O ~ ~
(A)
8 9
where R3 and Rs through ~10 are the same or different and are a hydrogen atom; ahalogen atom (preferably a fluorine, chlorine or bromine atom); a hydrocarbyl group
con~ininf~ up to about 10 carbon atoms each (e.g., a Cl to C10, and preferably a C,
S to C4 allcyl group, a C6 to C,O aryl group, a C3 to C10 cycloalkyl~group,-a C2 to C10,
and preferably a C2 to C4 alkenyl group, a C, to C10 aralkyl group, etc.); a
halohydrocarbyl group cont~inin~ up to about 10 carbon atoms and up to about 3
halogen atoms each; an -NR2, -SR, -OSiE~3, -SiR3, or -PR2 group in which R is a
hydrocarbyl group conf~inin~ up to about 10 carbon atoms. In ~L~ife.,c~d
embodiments R3 is an alkyl group, most preferably a methyl group, and at least four
and most preferably all six of R5 through R'~ are hydrogen atoms.
The 4,5-benzoindanols formed in this reaction likewise can exist in either of
two isomeric forms derived from the isomeric forms of the 4,5-benzoindanone(s) used
as the starting material. Such 4,5-benzoindanols are thus illustrated by formula (B~
below which depicts the 4,5-benzoindan-1-ols. The 4,5-benzoindan-3-ols have the
same formula except that the hydroxyl group is in the 3-position of the S-membered
ring instead of the l-position as shown.
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OH R3
o ~ \ (B)
R1~ ~ o
where R3 and Rs through R'~ are as described above.
Another embodiment of this invention is the process of forming 4,5-benzoin-
dene which comprises reducing a 4,5-ben~oindanone to a 4,5-benzoindanol as
S described above, and catalytically dehydrating the 4,~-benzoihdanol (Formula (B)
above? so formed. The 4,5-benzoindenes formed in this reaction can be depicted by
the ~ormula:
R ~ ~),l Rl~
where ~3 and R5 through R'~ are as described above. Formula (C) depicts an isomer
having a double bond of the S-membered ring in the 1-position. In another isomerthat double bond can instead be in tlle 2-position, and mixtures of these respective
isomers can bc formed.
The preferred method of effecling the dehydration step involves use of an
arylsulfonic acid catalyst such as p-toluenesulfonic acid. In conducting this reaction
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sequence the reduction of the benzoindanone (Formula (A) above) to the benzoindanol
(Formula (B) above) is preferably terminated by quenching the reaction mixture with
water or a suitable aqueous solution or mixture, and separating off the aqueous phase
before proGee-iin~ with the catalytic dehydration reaction. By con-lucting the
t 5 reduction step in a low boiling ether reaction medium such as tetrahydLoru~ , the
separations after the aqueous quench can be readily accomplished by extracting the
quenched reaction mixture with a liquid hydrocarbon, preferably a mononuclear
aromatic hydrocarbon such as toluene or xylene, having a higher boiling point orhigher initial boiling point than the ether, and distilling at least the ether from the
resultant extract. Use of an excess of the hydrocarbon provides, on completion of the
distillation, a suitable predominately hydrocarbonaceous reaction medium in which
to conduct the dehydration step. Moreover on completion of the dehydration, the
water formed during the dehydration plus residua1 water, if any, ~rom the quenching
step, can be readily removed by azeotropic ~ till~tion. While the catalytic
dehydration is best carried out using an arylsulfonic acid catalyst, other ways of
performing the dehydration can be used especially for laboratory scale operations.
Such methods include use of oxalic acid as dehydration catalyst or reaction of the
benzoindanol with dehydrating substances such as magnesium sulfate or molecular
sieves. For references describing such alternative albeit far less desirab}e procedures,
see Rohrmann et al. at Column 9, lines 41-43.
In summary therefore, a prere~led process sequence per this invention for con-
verting a 4,5-benzoindanone to a 4,5-benzoindene comprises: (a) a 4,5-benzoindanone
is reduced to a 4,5-benzoindanol in an ether-cont~inine reaction meflillm by use of an
al}cali metal borohydride and water or an alcohol or a mixture thereof; (b) the
reduction is terminated by quenching the reaction mi~cture with a suitably largeamount of water (or appropriate aqueous mixture); (c) a separation is made between
' the water and organic constituents of the reaction mixture, by extracting the quenched
reaction mixture with a liquid hydrocarbon having a higher boiling point or higher
initial boiling point than the ether, and, if present, the alcohol; ~d) distilling off said
ether and, if present, the alcohol to leave a liquid hydrocarbon solution of the 4,5-
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benzoindanol; (e) catalytically dehydrating 4,5-benzoindanol so formed to the
corresponding 475-benzoindene while in liquid hydrocarbon solution, and (f) removing
water from the dehydration reaction mixture by azeotropic distillation. In this
embodiment it is especially preferred that in Formulas (A), (B) and (C) above, R3 be
an alkyl group, most preferably a methyl group, and that at least four and most
preferably all six of Rs through Rl~ be hydrogen atoms.
Another embodiment of this invention comprises converting the 4,5-benzoin-
denes (Formula C above) to a silicon-, germ~nillm- or tin-bridged complex of theformula:
R
. R ~
l2 / M~ (D)
r ~ ,9
where R3 and R5 through Rl~ are as described above, M' is a silicon, germ~nillm or
tin atom (preferably a si}icon atom), and Rll and Rl2 are the same or different and
are a hydrocarbyl group cont~ining up to about 18 carbon atoms each (e.g., a Cl to
Cl8, and preferably a C, to C4 alkyl group, a C6 to Cl8 aryl group, a C3 to Cl8
cycloalkyl group, a C2 to C,8, and preferably a C2 to C4 alkenyl group, a C7 to C,8
aralkyl group, etc.); or a hydrocarbyl(oxyalkylene) or hydrocarbylpoly(oxyalkylene)
group containih1g up to about 100 carbon atoms ~preferably where the oxyalkylenemoiety or moieties are oxyethylene and or oxymethylethylene, and in the case of long
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chain polyoxyalkylenes, the oxyalkylene moieties ,are in random or block
arrangements. Most preferably, M~ is a silicon atom; Rl' and Rl2 are the same and
are Cl to C4 alkyl groups, most preferably methyl or ethyl groups, R3 is an alkyl
group, most preferably a methyl group, and at least four and most preferably all six
S of Rs through Rl~ are hydrogen atoms.
To produce the compounds of Formula (D) above, the benzoindenes (Formula
(C) above) are de~lolollal~d with a strong base such as butyllithium and reacted with
a suitable silicon, germanium or tin l~ac~lll, which can be depicted by the formula
RIlRl2MlX2 where X is a halogen atom (preferably a chlorine or bromine atom) andM', Rll and Rl2 are as described above. In a particularly preferred embodiment of
this invention these operations are conveniently conducted in a dialkyl ether medium,
typically a lower alkyl ether such as diethyl ether, dipropyl ether, methyl tert-butyl
~ ether, ethyl tert-butyl ether, methyl tert-amyl ether, or dibutyl ether, most preferably
diethyl ether. Unlilce the situation where tetrahydrofuran is used in this procedure,
the use of a liquid dialkyl ether enables the bridged product to form a slurry which
is easily sep~d from the liquid phase by such procedures as filtration,
centrifugation or ~leç~nt~tion. If an solvent such as tetrahydrofuran is used, it is
likely that a oily product will be formed which is hard to handle and to separate
cleanly without recourse to solvent exch~nging and an excessive amount of washing.
Thus use of a dialkyl ether such as diethyl ethyl has proven to greatly facilitate the
separation and recovery of the bridged product, and accordingly makes this operation
entirely feasible for use in large plant scale operations.
In still another embodiment, the bridged compound of Formula (D) above is
transformed into a metallocene complex of the formula:
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R R
R ~ X
where M2 is a group IV, V, or VI metal atom (i.e., Ti, Zr, Hf, -V, Nb, Ta, Cr, Mo,
or W); X' and x2 are the same or different and each is a halogen atom (preferably
a chlorine atom~; and Ml, R3 and R5 through Rl2 are as described above. Preferably
M~ is Ti, Zr or Hf, most preferably Zr; X' and x2 are chlorine atoms; Ml is a silicon
atom; Rll and Rl2 are the same and are C~ to C4 alkyl groups, most pre~erably methyl
or ethyl groups, R3 is an alkyl group, most preferably a methyl group, and at least
four and most preferably all six of R5 through Rl~ are hydrogen atoms.
Compounds of Formula (E) above are formed by deprotonating a bridged com-
pound of Formula (D) above with a strong base such as butyllithium and reacting the
deprotonated intermediate so formed with a suitable Group IV, V, or VI metal-con-
taining re~l~t~nt, such as a Group IV, V, or VI metal tetrahalide. The deprotonation
is typically performed in an ether medium such as tetrahydrofuran or lower dialkyl
ether. Thc metallation reaction can be conducted by adding the ether solution of the
deprotonated intermediate portionwise to a preformed complex or mixture of the
Group IV, V, or Vl metal-containing reactant and an ether such as tetrahydrofuran
in a hydrocarbon solvent such as toluene or xylenes or the like. However other
solvent systems and modes of addition can be used.
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A number of distinct advantages can be realized if the bridged metallocene of
Formula (E) is produced by adding a chelate diamine adduct of the Group IV, V orVl metal tetrahalide to a solution or slurry of a deprotonated bridged compound of
Formula ~D) above, such as a dilithium or disodium derivative thereof. Such a
S procedure, when properly carried out, results in improved filterability of the reaction
mixture, higher yields of product of formula (E), and product having higher ratios of
racemic isomers to meso forms, as co~ al ed to the reverse addition of such re~ct~ntc
such as shown in U. S. Pat. No. 5,556,997.
Indeed, the advantages of this embodiment may be realized not only with
dilithium or disodium derivatives of silicon-, germ~ni-lm- or tin-bridged complexes
depicted in Formula (D) but in addition, with dilithium or disodium derivatives of
silicon-, germ~nillm- or tin-bridged complexes analogous to those depicted in Formula
(D) having other cyclopentadienyl moieties regardless of whether the moieties are
composed of bridged single rings (e.g., cyclope~t~ nyl and hydrocarbyl-substituted
cyclopentadienyl moieties) or bridged fused rings (e.g., indenyl, hydrocarbyl-substi-
tuted indenyl, fluorenyl, or hydrocarbyl-~ .L;~ d fluorenyl moieties), and regardless
of whether the two bridged cyclopentadienyl moieties are the same or are different
from each other. Thus in this aspect of the invention dilithium or disodium deriva-
tives of silicon-, germanium- or tin-bridged cyclopentadienyl-moiety-cont~inin~ com-
pounds having 5 to about 75 carbon atoms in the molecule can be used as the ligand.
Examples of such ligands are given, for example, in U.S. Pat. Nos. 5tO17,714;
5,329,Q33; 5,455,365; 5,455,366; and 5,541,350.
The chelate ~ min~ adduct of a Group IV, V, or VI metal tetrahalide can be
formed from such amines as N,N,N',N'-tetramethyl~ minomethane, N,N,N',N'-
tetraethyl~ minomethane,N,N'-diethyl-N,N'-dimethyldi~ mi nomethane,N,N,N',N'-
tetramethylethylene~ min~, N,N,N',N'-tetraethylethylenetli~min~, N,N'-diethyl-
N,N'-dimethylethylenedi~min~, and like di~min~s capable of forming an adduct with
such metal tetrahalides. The preferred diamine is N,N,N',N'-tetramethylethylene-cii~min~.
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Various compounds of Formula (E) are useful as components for catalyst
systems for producing polyolefins such as polyethylene and polypropylene.
Examples 1-4 illustrate preferred procedures for cond~lcting the overall
sequence of steps that can be employed in the practice of this invention. Examples
5-7 illustrate preferred procedures for transforming the dilithium or disodium
derivatives of si}icon-, germanium- or tin-bridged cyclopentadienyl-moiety-cont~ining
compounds into the bridged metallocenes by addition thereto of the chelate diamine
adduct of the Group IV, V, or VI metal tetrahalide pursuant to this invention.
~xamples 8-10, which show procedures that can be used in the overall sequence ofreactions for effecting the same transformation, highlight the dramatic superiority and
advantages of the preferred procedures illustrated in Examples 5-7. Unless otherwise
specified, all percentages in the Example are by weight. It is to be clearly understood
that Examples 1-7 are for the purposes of illu~lld~illg current best modes for carrying
out the operations. None of the Examples is intended to limit, and should not beconstrued as limiting, the invention to the specific procedures set forth therein.
EXAMPLE 1
Ple~ald~ion of 2-hlIethyl-4.5-benzoindanone
A slurry of 577 g (4.322 mol) AICl3 in 25~) mL of methylene chloride was
cooled to 5~C. To the slurry 372 g (1.618 mol~ of 2-bromoisobutyryl bromide was
20 ~ added over 0.75 hour. After stirring for ().5 hour, a solution of 207 g (1.616 mol)
of naphthalene in 500 mL of methylene chloride was added at 5~C over 1.5 hour.
During the addition any H~l/HBr gas evolved overhead was scrubbed with a causticsolution. The resulting mixture was stirred for 0.5 hour at 5~C and 1 hour at room
temperature. The reaction slurry was then transferred to 2 to 3 liters of ice/water in
a separate flask with agitation. HCI/HBr gas formed during the hydrolysis was
scrubbed by a caustic solution. The organic phase (lower layer) of the hydrolyzed
mixture was separated and saved. The upper aqueous layer was extracted once with500 mL of methylene chloride. The combined organic phase and extract were
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washed with water (2x, 500 mL each) and the solvent was removed in vacuo to obtain
crude product as a brown oil. The brown oil was flashed under S mm ~Ig vacuum
and 158-160~C head temperature (or 170-210~C pot ternperature) to collect 276 g
(87~ yield) of product as an orange oil. NMR analysis of the oil confirmed it was
2-methyl-4,5-benzoindanone; GC analysis of the oil indicated it was 96% pure.
EXAMPLE 2
Preparation of 2-Methyl-4,~-benzoindanol and
Conversion to 2-Methvl-4.5-benzoindene
A solution of 2-methyl-4,5-benzoindanone (276 g, 1.408 mol) dissolved in 570
mL of THF and 570 mL of methanol was cooled to 5~C~ and solid NaBH4 (28 g,
0.74 mol) was added in portions to the solution over 45 Iminllt~s, After stirring for
one hour at 5~C and another hour at room temperature, the reaction mixture was
quenched with 570 mL of water and followed by 60 mL of concentrated HCI (to
bring the pH of the mixture to 2). The alcohols (2-methyl-4,5-benzoindanols) formed
were extracted with toluene (2x, 500 mL each) and the combined extracts were
washed with water (2x, 300 mL). The THF/methanol solvent in the toluene extract
was distilled off under atmospheric IJles~ul~. When the pot temperature reached ~
113~C, the distillation was stopped and the mixture was cooled. Once the pot
temperature was cooled down to about 80~C, 0.15 g of p-toluenesulfonic acid
monohydrate was added, and the mixture was heated up again for one more hour to
azeotrope off water ~25 mL theory). After the azeotropic distillation was completed,
all the toluene solvent in the mixture was removed under vacuum. 2-Methyl-4,5-
benzoindene (254 g, 100% yield) was obtained as a brown oil. Analysis by NMR
and GC confirmed the structure of the product and its purity was more than 95 % .
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E~AJMnPLE 3
Preparation of Dimethylsilylbis(2-methyl-4.5-benzoindene~
A solution of 567 mL (1.423 mol) of BuLi solution (2.5 M in hexanes3 was
added at room temperature over 1.5 hour to a solution of 256 g (1.422 mol) of 2-S methyl~,S-benzoindene in one liter of dry diethyl ether. The mixture was allowed
to reflux (39-43~C) during the addition. After the ad~ition the mixture was heated
at reflux for one hour and then cooled. At room temperature 92 g (0.7132 mol) ofdichlorodimethylsilane was added to the pot over a period of l.S hours. The resulting
mixture was stirred at room temperature overnight to form a slurry. Next morning400 mL of ether was distilled off from the mixture and the slurry in the pot wascooled to 10~C. The precipitated dimethylsilylbis(2-methyl-4,5-benzoindene) and
LiCI solids were filtered, and the cake was successively washed with ether (2x, 10()
mL each), a~ueous methanol (2x, 100 mL methanol + 100 mL water, each) and
followed by acetone (2x, S0 mL each). The cake was dried under S mm Hg/50~C
lS to thoroughly remove all methanol/ water to give 178 g (60% yield) of
dimethylsilylbis(2-methyl-4,5-benzoindene) as tan-colored solids. The structure and
purity of this product were conflrmed by NME~ analysis.
I~XAMPL~ 4
Preparation of Dimethylsilylbis(2-methyl-
4.5-benzoindenyl)zirconium Dichloride
Dimethylsilylbis(2-methyl-4,5-benzoindene) (100.27g,0.241 mol)waspartially
dissolved in 300 mL of THF. This slurry was cooled to 0~C and then two
e~uivalents of n-BuLi (193 mL of 2.5M in hexanes; 0.48 mol) were added dropwise.A clear, amber solution of ~he dilithium derivative of the silyl-bridged reactant
formed. After the addition was complete, the reaction mixture was allowed to warm
to room temperature.
In a second flask, ZrC14 (56.8 g; 0.244 mol) was slurred in S00 mL of
anhydrous toluene. THF (70 g; 0.97 mol) was added to this slurry to form the
14
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complex, ZrCI4(THF)2. The reaction was stirred overnight and then the solution of
the dilithium derivative was added dropwise to the ZrCI4(THF)2 slurry over 75
minutes. An orange-yellow slurry formed. After 2 hours, the reaction mixture washeated in an oil bath and 350 mL of solvent were flash distilled. A vacuum was
applied and an additional 450 mL of volatiles were removed. The slurry was stirred
for 3 hours and then the solids were isolated by filtration on a coarse frit. The solids
were washed with 20 mL of toluene, 40 mL of hexanes and then dried in vacuo. Theyield of yellow solid was 100.3 grams. A IH NMR showed the metallocene was
present in a rac/meso ratio of 1:1.
The crude product was slurried in 900 mL of anhydrous THF and heated to
reflux overnight. The slurry was cooled to room temperature and filtered on a coarse
frit. The yellow solids were washed with 35 mL of THF and dried in vacuo. The
dried weight of dimethylsilylbis(2-methyl-4,5-benzoindenyl)zirconium dichloride was
41.4 grams (30~ yield based on the initial silyl-bri~dged reactant). lH NMR
determined the rac/meso ratio to be greater than 99:1.
CA 0223036~ 1998-02-24
W O 97149712 PCTrUS97110684 -
~ CPLE 5
Preparation of Dimethylsilylbis~2-methyl-
4.5-benzoindenyl)zirconium Dichloride
In a dry box, 12 g of THF and ZrC14 (2.33 g; 10 mmol) were quickly mixed
S in a 50 mL flask (while the temperature increased from 22~C to 38~C due to the heat
of ether adduct formation). The resultant white slurry was stirred at about 30~C for
2.5 hours. N,N,N',N'-tetramethylethylene ~ mine (TMEDA, 0.85 g; 7.3 mmol)
was added (in an approximately 5-minute period) and a white solid adduct dissolved
to form a solution. After stirring at about 27~C for approximately 10 minutes, the
diamine adduct solution was used for reaction with the dilithium derivative of the
silyl-bridged reactant as now to be described.
To a second 50 mL flask, THF (18 g) was added to dissolve 5.72 g of the di-
Iithiumderivativeofdimethylsilylbis(2-methyl-4,5-benzoindene) ~ (THF/Et20)2powder
(72.2% normalized "Li2LIG"; approximately 9.6 mmoles), cont~ining ca. 2.7 wt%
of the corresponding monolithium derivative ("LiLlG") as an impurity, ca. 23.6%
THF and ca. 1.5% Et20. Et20 (6 g) was added. The above ZrCI4-~ minP adduct
solution was added to this solution during a period of about 7 minlltes while the
temperature increased from 26~C to 30~C. Additional THF (0.5 g) was used to washthe contents of the first ~flask into the mixture in the second flask. The reaction mass
was stirred at about 30~C for about 21 hours and then the reaction mass was heated
up to 60~C to strip 5.2 g of Et20/THP off before cooling the mixture down to 24~C.
The slurry was easily filtered (under ca. 15 inches of Hg vacuum) and the wet cake
was washed with 3 g THF. 3.42 Grams (ca. 59.4% recovery) of dried yellow
powder were obtained which lH NMR indicated to contain 91.4% (normalized)
racemic dimethylsilylbis(2-methyl~,S-benzoindenyl)zirconium dichloride, 3.8% of
the meso form, and 4.8% THF, and thus a racemic/meso ratio of 96/4.
16
CA 0223036=, 1998-02-24
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E~A~MnPLE 6
Preparation of Dimethylsilylbis(2-methyl-
4.5-benzoindenyl)zirconium Dichloride
THF (12.36 g) and ZrCI4 (2.40 g; 10.3 mmol) were mixed in a 50 mL flask
(while the temperature increased from 23~C to 38~C). After stirring at about 30~C
for about one hour, TMEDA (0.88 g; 7.6 mmol) was added into the white slurry over
a S-minute period to obtain a solution of the ZrCI4-~ min~ adduct. This solution was
added in about a 7-minute period to a solution (31.88 g) contAining about 4.28 gLi2LIG (about 10 mmol), 7.3 g Et20, 20.1 g THF, O.lS g (about 0.36 mmoles~
LiLIG, and 0.04 g hexane (the last two of which were undesired impurities) at
temperatures ranging from 25 to 30~C. Additional THF (0.5 g) was used for rinsing
the co~ ls of the first flask into the second flask. The reaction mass was stirred at
ca. 30~C for ca. 19.5 hours. Then the mixture was heated to 60~C to strip of~ 7.81
g of Et20 and THF. After cooling to 24~C and removal of a sample (0.8 g), the
slurry was easily filtered. The wet cake (5.97 g) was treated with 7 g THF on the
filter (for further removal of LiCl~ at ambient temperature for 2 hours. Tnen the wet
cake was filtered, washed with 3 g THF and then with 2 g methylene dichloride
(MeCI2), further treated twice with 4 g MeCl2 for ca. 1 hour each time, and thendried to leave 3.06 g of a purified, nice yellow product which by NMR contained
95.1% (normalized) racemic dimetihylsilylbis(2-methyl-4,5-benzoindenyl)zirconiumdichloride, 1.4% of the meso form, 1.2% THF, and 2.3% MeCI2. Thus NMR
inclir.~t-~.d the racemic/meso ratio was 98.511.5. ICP inrli~t~.tl the product contained
14.6% Zr and 655 ppm Li (ca. 0.4% LiCI). The recovery was ca. 53.1% (or ca.
55.1 % including the 0.8 g sample). Analysis of the filtrates: The total THF filtrate
(38.1 g) showed 0.45 % (normalized) racemic dimethylsilylbis(2-methyl-4,5-
benzoindenyl)zirconium dichloride, 0.38% of the meso form (rac/meso = 54/46),
2.1% TMEDA, 7.9% Et20 and 89.1% THF. The total MeCI~ filtrate (S.S1 g)
showed 0.8~ racemic dimethylsilylbis(2-methyl-4,5-benzoindenyl)zirconium
dichloride, 0.2% meso form, 0.2% Et20, 20.6% THF and 78.2% MeC!2.)
CA 02230365 1998-02-24
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EXAMPLE 7
Plel~alalion of Dimethylsilylbis(2-methyl-
4.5-benzoindenyl)zirconium Dichloride
~rCl4 (2.33 g; 10 mmol) and THF (12 g) were quickly mixed. TMEDA (1.16
S g; 10 mmol) was added to the slurry to produce a thin slurry. The resultant slurry
was added over a 7-minute period to a solution at ca. 30~C formed from 5.72 g ofLi2LIG-(THF/Et20)2 solid and 15 g of THF, and 0.5 g of THF was used for rinsing
product from the first flask into the second. The reaction mass was stirred at ca.
28~C for 20 hours and heated to and caused to ride at 50~C for 1.2 hours. After the
reaction mass was cooled down, a slurry sample (0.68 g) was taken, and it had anestimated content of 8.7% racemic dimethylsilylbis(2-methyl-4,5-
ben~oindenyl)zirconium dichloride, 0.9% meso form (racemic/meso = 90.6/9.4),
3.3% TMEDA, 86.7% THF and 0.4% Et20. The filtration was relatively easy, and
the wet cake was washed with 6 g THF and dried to give 2.48 g ~ca. 43 % recovery)
of product having 93.9% (normalized) racemic dimethylsilylbis(2-methyl-4,5-
benzoindenyl)zirconium dichloride, 2.8% of the meso iorm, and 3.2% THF. The
total ~lltrate- (31.2 g) contained 1.1% racemic dimethylsilylbis(2-methyl~,5-
benzoindenyl)zirconium dichloride, 0.8 wt% of the meso product (rac/meso =
~8/42), 0.3% Et20, 4% TMEDA and 93.8% THF.
EXAMPI,E 8
Preparation of Dimethylsilylbis(2-methyl-
4.5-benzoindenyl)zirconium Dichloride
In this run, the ZrCl4 was added to the dilithium ligand as the ZrCl4-(THF)2
adduct; no chelating diamine was used. ZrCl4 (2.80 g; 12 mmol) and 15 g of THF
were quickly mixed and stirred for 1 hour resulting in a white slurry. The slurry was
added to a 22.8 g solution composed of 20.9% Li2LIG-(THF/Et2O)2, (ca. 11.1
mmol), 78% THF, 0.1% LiLIG and 1.1% pentane at about 25-30~C over a 20-
minute period using an additional 3 g of THF for wash. After 21-hour riding at
ambient temperature, the slurry was heated up to 60~C for 4 hours (to improve the
18
CA 02230365 1998-02-24
W O 97/49712 PCTrUS97/10684 -._
filtration). Two slurry samples (0.5 & 0.4 g) were taken before and after the heatup
and had 6.2 & ~ 6.1~ (norr~alized) racemic dimethylsilylbis(2-methyl~,S-
benzoindenyl)zirconium dichloride, and 0.6 & 0.8% of the meso product (rac/meso
= 91.2/8.8 & 88.4/11.6), respectively. The filtration was slow (about l.S hours or
about 5 to 10 times slower than when operating as in Examples 5-7 above). After the
product was washed with 6 g of THF and dried, 2.36 g of racemic dimethylsilylbis(2-
methyl-4,5-benzoindenyl)zirconium dichloride product were obtained (ca. 34.1%
recovery) with 89.5 % (norm~li7ed~ racemic dimethylsilylbis(2-methyl-4,5-
benzoindenyl)zirconium dichloride, 0.9 wt% of the meso ~orm, and 3.7 wt% THF
(likely adducted) . The filtrate (35.3 g) contained by analysis 1.5 % racemic
dimethylsilylbis(2-methyl-4,5-benzoindenyl)zirconium dichloride, 1.2% of the meso
product (rac/meso = 56/44), 96.9% THF and 0.4% pentane.
EXAMPLl~ 9
Preparation of Dimethylsilylbis(2-methyl-
4.5-benzoindenyl)zirconium Dichloride
In this run the reverse addition was used, i.e., the dilithium ligand was added
to the ZrCI4-chelate ~ mine adduct. Thus ZrCI4 (2.80 g; 12 mmol) and 15 g of
THF were quickly mixed. TMEDA (0.39 g; 3.4 mmol) was added to obtain a
solution. After this was stirred for 20 minutes, a solution formed from 6.87 g of
Li2LIG solid (ca. 12 mmol) and 15 g of THF was fed with a dropping funnel to theabove ZrCI4-TMEDA solution at ca. 3~)~C for 20 minllt~s After this mixture was
stirred at ca. 30~C for 21 hours, a slurry sample (0.52 g) showed by analysis 4.7%
(normalized) racemic dimethylsilylbis(2-methyl-4,5-benzoindenyl)zirconium
dichloride, 0.75 % of the meso product (rac/meso = 86/14), 93.3 % THF, 1 .Ot~ Et20
and 0.3 wt% TMEDA, which indicated that the reaction yield of racemic
dimethylsilylbis(2-methyl-4,5-benzoindenyl)zirconium dichloride was much lower.
The slurry was heated up to and caused to ride at 60~C for 1.3 hours and was then
cooled down. The workup was termTn~t~d because the filtration was very slow.
19
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W O 97/49712 PCT~US97/10684 -._
I~XAMPLE 10
Preparation of Dimethylsilylbis(2-methyl-
4~5-benzoindenyl)zirconium Dichloride
Again a reverse addition was used but in this case, the reactants were used as
slurries. Thus, ZrC14 (1.40 g; 6 mmol) and 10 g of EtA0 were quickly mixed. THF
(1.3 g; 18 mmol) and TMEDA (0.2 g; 1.7 mmol) were added yielding a white slurry.After stirring for 20 minlltes, 3.44 g of Li.LlG-~HF/Et0)2 and 10 g of Et20 wereadded in about S minutes. The resultant slurry was stirred at about 30~C for 18
hours. A sample (0.49 g) had 6.6% (normalized) racemic dimethylsilylbis(2-methyl-
4,5-benzoindenyl)zirconium dichloride, and 6.0% of the meso product ~rac/meso =
52.6/47.4). THF (15 g) was added to the mixture and the reaction mass was heatedup to 50~C and some Et~0/THF was stripped off. After the reaction mass cooled
down, the slurry was easily filtered. However, when 10 g of TE~F were added for
purification (e.g. for removal of LiCI and the meso product), the filtration became
very slow. Finally, 3.68 g of yellow powder were obtained which by analysis had
48.3% (normalized) racemic dimethylsilylbis(2-methyl-4,5-benzoindenyl)zirconium
dichloride, 42.6% of the meso form (rac/meso = 63.1/46.9), 8.8% THF and 0.9%
Et20 (likely both adducted).
