Novel C1 symmetric zirconocenes containing substituted fluorenyl moieties for the polymerization of olefins

Article abstract of DOI:10.1016/S0022-328X(03)00239-0

The synthesis and polymerization behavior of four new asymmetric ansa -metallocenes containing a 2,7-disubstituted fluorenyl moiety and an indenyl moiety is reported. Three of the four catalysts, dichloro[η⁵-1-indenyl(1-methylethylidene)-[2,7-bis- (2,4,6-trimethylphenyl)-η⁵-9-fluorenyl]zirconium (11), dichloro[η⁵-1-indenyl(1-methylethylidene)-[2,7-bis- (2,6-dimethylphenyl)-η⁵-9-fluorenyl]zirconium (12), and dichloro[η⁵-1-indenyl(1-methylethylidene)-[2,7-bis- (2-methylphenyl)-η⁵-9-fluorenyl] zirconium (13) were highly active for the polymerization of both ethylene and propylene when activated with excess methylaluminoxane (MAO). Dichloro[η⁵-1-indenyl(1-methylethylidene)- [2,7-dibenzyl-η⁵-9-fluorenyl]zirconium (14) was poorly active for the polymerization of ethylene and was therefore not evaluated as a propylene catalyst. The activities for propylene polymerizations with catalysts 11-13 increased as the size of the substituents around the ligand framework increased, following the trend 11>12>13. Molecular weights of the polypropylenes decreased as the temperature was increased. The molecular weight data follows the same trend (11>12>13) as the activity data, wherein the largest substituents gave rise to the highest molecular weights.

Full text of DOI:10.1016/S0022-328X(03)00239-0

Journal of Organometallic Chemistry 675 (2003) 97Á104
/
www.elsevier.com/locate/jorganchem
Novel C1 symmetric zirconocenes containing substituted fluorenyl
moieties for the polymerization of olefins
John J. Esteb a, Mandy Bergeron b, Carol N. Dormady b, James C.W. Chien b,
Marvin D. Rausch b,*
a Clowes Department of Chemistry, Butler University, Indianapolis, IN 46208, USA
b Department of Chemistry, University of Massachusetts, Lederle Grad Research Center, Amherst, MA 01003-4510, USA
Received 10 December 2002; received in revised form 24 March 2003; accepted 27 March 2003
Abstract
The synthesis and polymerization behavior of four new asymmetric ansa-metallocenes containing a 2,7-disubstituted fluorenyl
moiety and an indenyl moiety is reported. Three of the four catalysts, dichloro[h5-1-indenyl(1-methylethylidene)-[2,7-bis-(2,4,6-
trimethylphenyl)-h5-9-fluorenyl]zirconium (11), dichloro[h5-1-indenyl(1-methylethylidene)-[2,7-bis-(2,6-dimethylphenyl)-h5-9-fluor-
enyl]zirconium (12), and dichloro[h5-1-indenyl(1-methylethylidene)-[2,7-bis-(2-methylphenyl)-h5-9-fluorenyl] zirconium (13) were
highly active for the polymerization of both ethylene and propylene when activated with excess methylaluminoxane (MAO).
Dichloro[h5-1-indenyl(1-methylethylidene)-[2,7-dibenzyl-h5-9-fluorenyl]zirconium (14) was poorly active for the polymerization of
ethylene and was therefore not evaluated as a propylene catalyst. The activities for propylene polymerizations with catalysts 11Á
increased as the size of the substituents around the ligand framework increased, following the trend 11ꢀ12ꢀ13. Molecular weights
of the polypropylenes decreased as the temperature was increased. The molecular weight data follows the same trend (11ꢀ12ꢀ13)
/
13
/
/
/
/
as the activity data, wherein the largest substituents gave rise to the highest molecular weights.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Zirconocenes; Asymmetric metallocenes; Polypropylene; Olefin polymerization
1. Introduction
the molecular weight of the polymer produced using
tetrahydrofluorenyl- and octahydrofluorenyl-containing
zirconocenes was very low.
A major focus of our research program has been the
design and synthesis of novel asymmetric C1 catalyst
precursors for the polymerization of ethylene and
propylene. Both Thomas et al. [1] and Rieger et al. [2]
In an effort to increase the molecular weight of
polymers produced using indenylÁfluorenyl C1 sym-
/
metric zirconocenes, we have investigated the effect of
varying the bridging moiety to create a more sterically
biased ligand environment [3]. The introduction of a
sterically crowded environment around the metal center
did increase the molecular weight of polymer produced
slightly, presumably by inhibiting the chain termination
mechanism of the growing polymer chain. However, the
overall molecular weights obtained for the polymers
were still relatively low.
In the present study, further attempts to increase the
molecular weight of polymers obtained using C1 sym-
metric zirconocenes were probed. Alt et al. [4] have
shown that in bridged Cs symmetric zirconocenes, a 2,7-
bis(mesityl)fluorenyl moiety or other related 2,7-disub-
stituted fluorenyl moieties can dramatically increase
have studied several mixed ring indenylÁfluorenyl
/
metallocenes with specific attention focused on the
effects of substituents on the indenyl moiety. More
recently, Thomas has investigated the effects of chan-
ging the fluorenyl moiety to its partially or fully
saturated tetrahydrofluorenyl and octahydrofluorenyl
analogs, respectively [1c,1d]. In that study, the authors
found that these modifications could both increase the
activity of the catalytic species and also increase the
overall stability of the catalyst precursor. Unfortunately,
* Corresponding author. Fax: ꢀ
E-mail address: rausch@chem.umass.edu (M. Rausch).
/1-413-5454490.
0022-328X/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00239-0

98
J. Esteb et al. / Journal of Organometallic Chemistry 675 (2003) 97Á104
/
polymer molecular weight. Based on the work of
Thomas et al. [1c,1d] it was therefore of interest to
study whether a similar effect could be obtained by
replacing the fluorenyl moiety in C1 symmetric zircono-
cenes with a 2,7-disubstituted fluorenyl analog.
The reactions proceeded in good yield, ranging from 70
to 81%. Depending on the steric and electronic nature of
the organic bromide, varying reaction times were
necessary to achieve optimal yields. Formation of 2,7-
bis(mesityl)fluorene (1) and 2,7-bis(2,6-dimethylphe-
nyl)fluorene (2) required refluxing the reaction
mixture overnight to ensure completion. In contrast,
2,7-bis(2-methylphenyl)fluorene (3) and 2,7-dibenzyl-
fluorene (4) were formed after only 30 min of heating
at reflux.
2. Results and discussion
2.1. Synthesis of organic ligands
Several new ansa-ligands were synthesized by mod-
ification of a general literature procedure for making
isopropylidene-bridged ligands [6]. Initially, reaction of
2,7-Bis(mesityl)fluorene (1) and several new 2,7-dis-
ubstituted fluorenes 2Á4 were synthesized by reaction of
/
1Á
subsequent reaction with 2,3-benz-6,6-dimethylfulvene
(6) gave the corresponding ligands (7Á10) in good yields.
Crystallization from pentane or acetone produced 7Á10
in elementally pure form.
/4 with one equivalent of butyllithium, followed by
2,7-diiodofluorene (5) [5] with the Grignard salt of an
aryl or benzylic bromide in the presence of a catalytic
amount of [1,3-bis(diphenylphosphino)propane]-di-
chloronickel(II) (Ni(dppp)Cl2) following a modified
version of the procedure developed by Alt et al. [4].
/
/

J. Esteb et al. / Journal of Organometallic Chemistry 675 (2003) 97Á
/104
99
2.2. Synthesis of zirconocenes
which could in turn inhibit monomer coordination and
lead to decreased polymerization activity.
Synthesis of zirconocenes 11Á
double deprotonation of ligands 7Á
/
14 was accomplished by
The activities obtained using 11Á
/
13 ranged from ca.
107 to 1ꢁ108 depending on polymerization tem-
/10 in Et2O with two
3ꢁ
/
/
perature and catalyst structure. The highest activity
overall was obtained with complex 13 at 50 8C, which is
also the least sterically hindered complex. In general, for
all of the species tested, the activity was lowest at 0 8C
and greatest at 50 8C.
equivalents of n-butyllithium to initially produce the
corresponding dilithium salts. The dilithium salts were
then reacted with one equivalent of ZrCl4 in an Et2O
solution to produce the desired zirconocenes. Overall
yields ranged from ca. 13Á
14 was necessary due to the high sensitivity of these
compounds to air and moisture. Furthermore, once 11Á
/
21%. A rapid workup of 11Á
/
For complexes 11Á13, the maximum molecular
/
weights were obtained at low temperatures. Molecular
weights of the polymers decreased as the polymerization
temperature was increased. In general, the highest
molecular weights were obtained with the most hindered
/
14 were isolated as solids, exposure to solvent resulted in
almost immediate decomposition of the zirconocenes.
Hence, polymerizations were run by directly adding the
complexes following the general trend, 11ꢀ
/
12ꢀ
/
13.
solid metallocenes to an MAOÁtoluene solution. This
/
Furthermore, 11Á13 all exhibited greater activity and
/
allowed for the rapid generation of the active cationic
species which limited the amount of decomposition
observed.
produced polyethylene of higher molecular weights than
the unsubstituted derivative, 2-fluorenyl-2-indenyl pro-
pane zirconium dichloride synthesized by Alt et al.
which exhibited an activity of 1.7ꢁ
107 and produced
/
polyethylene with Mw of 100,000 Da [6]. This trend
supports our hypothesis that the added steric bulk
around the metal center should increase the resulting
polymer molecular weight by decreasing accessibility of
the growing polymer to chain termination steps.
2.3. Ethylene polymerization
Compounds 11Á13 were highly active in catalyzing
/
the polymerization of ethylene when activated with
MAO (Table 1). Interestingly, 14 was poorly active in
catalyzing the polymerization of ethylene when acti-
vated with MAO, giving only traces of polyethylene at
all of the polymerization temperatures probed. The poor
activity exhibited by 14 could be attributable to
coordination of the pendant benzyl groups to the active
metal center. Benzylic coordination could block pre-
viously vacant coordination sites on the metal center,
2.4. Propylene polymerization
Due to its poor activity in ethylene polymerizations,
14 was not evaluated as a potential propylene catalyst.
However, 11Á/13 were shown to be highly active in
catalyzing the polymerization of propylene when acti-

100
J. Esteb et al. / Journal of Organometallic Chemistry 675 (2003) 97Á104
/
Table 1
Polymerization of ethylene with zirconocene complexes activated with MAO a
Catalyst
Temperature (8C)
Yield (g) b
10ꢂ7 A c
Tm (8C)
Mw
11
11
11
12
12
12
13
13
13
14
14
14
0
20
50
0
0.519
0.499
0.509
0.289
0.469
0.489
0.569
0.669
0.569
/
0.05
0.05
0.06
0.02
0.04
0.03
0.08
0.11
0.06
5.7
6.3
8.8
3.1
5.9
8.4
6.2
8.5
9.8
135
135
134
134
136
136
133
135
134
750,000
681,000
452,000
697,000
611,000
359,000
584,000
422,000
325,000
/
/
/
20
50
0
/
/
/
20
50
0
/
/
Trace
Trace
Trace
Á/
Á/
Á/
Á/
Á/
Á/
Á/
Á/
Á/
20
50
a
Polymerization conditions: [Zr]ꢃ
/
5 mM; Al/Zrꢃ
Yields are averages of duplicate runs.
Activityꢃg of PE/(mol Zr)(conc. of monomer)(h).
/
4000:1; reaction timeꢃ5 min.
/
b
c
/
vated with MAO (Table 2). The activities obtained
ranged from ca. 2.3ꢁ
106 to 9.6ꢁ106, depending on
to catalyze the polymerization of ethylene and propyl-
ene. Three of the four catalysts, 11Á13, were active for
/
/
/
polymerization temperature and catalyst structure. The
highest activity was obtained with 11 at 50 8C. The
activities of the catalysts also increased as the size of the
the polymerization of both ethylene and propylene.
Compound 14 was poorly active for the polymerization
of ethylene and was therefore not evaluated as a
propylene catalyst.
substituents increased, following the trend 11ꢀ
/
12ꢀ13,
/
which is further illustrated in Table 2.
In general, for the polymerization of propylene, the
most sterically hindered catalysts are more active and
produce polymers of higher molecular weights than do
their less hindered counterparts, as is evidenced by the
direct trend as one goes from 2,4,6-trimethylphenyl to
2,6-dimethylphenyl to 2-methylphenyl to no substitu-
ents, respectively.
The highest molecular weight polypropylenes were
also obtained using catalyst 11. A molecular weight of
189,000 was obtained at 50 8C using 11, which is among
the highest Mw polypropylene produced using a C1
catalyst of this type [1]. Molecular weights decreased as
the temperature was increased. The molecular weight
data follows the same trend (11ꢀ
/
12ꢀ13) as the activity
/
data, wherein the largest substituents give rise to the
highest molecular weights.
4. Experimental
All reactions were carried out under an inert argon
atmosphere using standard Schlenk techniques. The
argon was purified by drying with phosphorus pent-
oxide, calcium chloride and molecular sieves, and
deoxygenated with BTS catalyst. Toluene, hexane,
diethyl ether, and pentane were distilled from Na/K
alloy under argon. Methylene chloride was distilled
under argon from calcium hydride. Tetrahydrofuran
(THF) was dried initially over sodium wire, distilled
from sodium/benzophenone under argon, and finally
distilled from Na/K alloy under argon.
Methylaluminoxane was purchased from Akzo No-
bel. Celite was purchased from Fisher Scientific. 2,3-
Benz-6,6-dimethylfulvene (6) [7] and 2,7-diiodofluorene
(5) [5] were synthesized via literature procedures. All
other reagents were purchased from Aldrich and were
used without further purification. 1H-NMR spectra
were recorded on a Varian XL-200 spectrometer using
Me4Si as an internal standard. Mass spectrometry was
performed by the Mass Spectrometry Center, University
3. Conclusion
In summary, we have synthesized four new C1
symmetric metallocenes and have studied their ability
Table 2
Polymerization of propylene with zirconocene complexes activated
with MAO a
Catalyst Temperature (8C)
Yield (g) b
10ꢂ6 A c Mw
11
11
12
12
13
13
20
50
20
50
20
50
3.419
1.889
2.669
1.009
1.419
0.459
/
0.22
0.29
0.29
0.17
0.13
0.34
8.2
9.6
6.4
5.1
3.4
2.3
189,000
/
156,000
163,000
132,000
98,000
/
/
/
/
58,000
a
Polymerization conditions: [Zr]ꢃ
30 min.
Yields are averages of duplicate runs.
Activityꢃg of PP/(mol of Zr)(conc. of monomer)(h).
/
25 mM; Al/Zrꢃ
/4000:1; reaction
timeꢃ
/
b
c
/

J. Esteb et al. / Journal of Organometallic Chemistry 675 (2003) 97Á
/104
101
of Massachusetts, Amherst. Microanalyses were per-
formed by the Microanalytical Laboratory, University
of Massachusetts, Amherst, MA.
anhyd. MgSO4, filtered, and the solvent removed.
Crystallization from toluene produced 6.74 g (81%) of
3 as white crystals, m.p. 165Á166 8C. Anal. Found: C,
/
1
93.52; H, 6.56 C27H22. Calc.: C, 93.60; H, 6.40%. H-
NMR (CDCl3): d 7.84 (d, 2H, aromatic H); 7.50 (s, 2H,
4.1. 2,7-Bis-(2,6-dimethylphenyl)fluorene (2)
aromatic H); 7.37Á
/
7.24 (m, 4H, aromatic H); 3.99 (s,
An argon purged 250 ml three neck flask was
equipped with an addition funnel, gas inlet valve,
magnetic stir bar, and a reflux condenser attached to a
mercury overpressure valve. Magnesium turnings (1.2 g,
49 mmol) were suspended in 50 ml of dry Et2O. Next,
0.25 ml of 1,2-dibromoethane was added to the flask.
The solution began to turn cloudy and 9.07 g (49 mmol)
of 2-bromo-m-xylene was slowly added to the reaction
flask via the addition funnel. The suspension was heated
at reflux overnight.
To a second argon purged 250 ml round bottom flask
was added 10.0 g (24 mmol) of 5, 0.20 g (0.4 mmol) of
Ni(dppp)Cl2, and 50 ml of dry Et2O under constant
stirring. Using a filter cannula, the Grignard solution
was transferred dropwise into the flask. Upon comple-
tion of the addition, the suspension was heated at reflux
overnight. The suspension was cooled of to 0 8C and
was slowly hydrolyzed with 3 M HCl. Washing with
saturated NaHCO3 followed by extraction with Et2O
produced a yellow solution, which was dried with
anhyd. MgSO4, filtered, and the solvent removed.
Crystallization from ethyl acetate afforded 6.28 g
2H, C5Á
/
sp3); 2.32 (s, 6H, CH3).
4.3. 2,7-Dibenzylfluorene (4)
An argon purged 250 ml three neck flask was
equipped with an addition funnel, gas inlet valve,
magnetic stir bar, and a reflux condenser attached to a
mercury overpressure valve. Magnesium turnings (1.2 g,
49 mmol) were suspended in 50 ml of dry Et2O. Next,
0.25 ml of 1,2-dibromoethane was added to the flask.
The solution began to turn cloudy and 5.9 ml (49 mmol)
of benzyl bromide was slowly added to the reaction flask
via the addition funnel. The suspension was heated at
reflux for 2 h.
To a second argon purged 250 ml round bottom flask
was added 10.0 g (24 mmol) of 5, 0.20 g (0.4 mmol) of
Ni(dppp)Cl2, and 50 ml of dry Et2O under constant
stirring. Using a filter cannula, the Grignard solution
was transferred dropwise into the flask. Upon comple-
tion of the addition, the suspension was heated at reflux
for 30 min. The suspension was cooled of to 0 8C and
was slowly hydrolyzed with 3 M HCl. Washing with
saturated NaHCO3 followed by extraction with Et2O
produced a yellow solution, which was dried with
anhyd. MgSO4, filtered, and the solvent removed.
Crystallization from toluene afforded 5.98 g (72%) of
(70%) of 2 as white crystals, m.p. 258Á
/
259 8C. Anal.
Found: C, 92.43; H, 7.03 C29H26. Calc.: C, 93.00; H,
1
7.00%. H-NMR (CDCl3): d 7.89Á
/
7.13 (m, 12H, aro-
sp3); 2.13 (s, 12H, CH3).
matic H); 3.99 (s, 2H, C5Á
/
4 as white crystals, m.p. 122Á
93.52; H, 6.66 C27H22. Calc.: C, 93.60; H, 6.40%. H-
NMR (CDCl3): d 7.64 (d, 2H, aromatic H); 7.31Á7.17
(m, 14H, aromatic H); 4.04 (s, 4H, C6-a-CH2); 3.78 (s,
2H, C5Á
sp3).
/
124 8C. Anal. Found: C,
1
4.2. 2,7-Bis-(2-methylphenyl)fluorene (3)
/
An argon purged 250 ml three neck flask was
equipped with an addition funnel, gas inlet valve,
magnetic stir bar, and a reflux condenser attached to a
mercury overpressure valve. Magnesium turnings (1.2 g,
49 mmol) were suspended in 50 ml of dry Et2O. Next,
0.25 ml of 1,2-dibromoethane was added to the flask.
The solution began to turn cloudy and 5.9 ml (49 mmol)
of 2-bromotoluene was slowly added to the reaction
flask via the addition funnel. The suspension was heated
at reflux for 2 h as all of the magnesium had been
consumed.
To a second argon purged 250 ml round bottom flask
was added 10.0 g (24 mmol) of 5, 0.20 g (0.4 mmol) of
Ni(dppp)Cl2, and 50 ml of dry Et2O under constant
stirring. Using a filter cannula, the Grignard solution
was transferred dropwise into the flask. Upon comple-
tion of the addition, the suspension was heated at reflux
for 30 min. The suspension was cooled of to 0 8C and
was slowly hydrolyzed with 3 M HCl. Washing with
saturated NaHCO3 followed by extraction with Et2O
produced a yellow solution, which was dried with
/
4.4. 9-[1-(Inden-3-yl)-1-methylethyl]-2,7-bis(2,4,6-
trimethylphenyl)-fluorene (7)
To an argon purged Schlenk tube was added 1.0 g (2.5
mmol) of 1 and 30 ml of dry Et2O. The solution was
cooled to 0 8C and 1.56 ml of a 1.6 M solution of
butyllithium in hexane (2.5 mmol) was added dropwise.
The solution was warmed to room temperature (r.t.) and
stirred for 4 h. Next, the solution was cooled to 0 8C and
0.39 g (2.5 mmol) of 2,3-benz-6,6-dimethylfulvene (6)
was added. Upon completion of the addition, the
solution was warmed to r.t. and stirred overnight. After
hydrolysis with aqueous NH4Cl, the organic layer was
separated. The aqueous layer was extracted with 2ꢁ10
/
ml of Et2O and the organic layers were combined. The
resulting organic solution was then dried with MgSO4,
filtered, and the solvent removed. The resulting yellow
foam was triturated with pentane and crystallized from

102
J. Esteb et al. / Journal of Organometallic Chemistry 675 (2003) 97Á104
/
acetone resulting in 0.92 g (66%) of 7 as a light yellow
solid, m.p. 203Á205 8C. Anal. Found: C, 92.16; H, 7.47
C43H42. Calc.: C, 92.42; H, 7.58%. HRMS (EI) Calc. for
7.17 (m, 18H, aromatic H); 6.18 (s, 1H, C5Á
4.86 (s, 1H, C5-Fluorene); 3.36 (s, 2H, C5Á
Ind-sp3); 2.26
(s, 6H, o-CH3); 1.29 (bs, 6H, CH3ÃCÃCH3).
/
Ind-sp2);
/
/
/
/
1
C43H42: 558.329 Found: 558.330. H-NMR (CDCl3): d
7.95Á
sp2); 4.85 (s, 1H, C5-Fluorene); 3.28 (s, 2H, C5Á
2.33 (s, 6H, o-CH3); 2.10 (s, 6H, o-CH3); 1.93 (s, 6H, p-
CH3); 1.22 (bs, 6H, CH3ÃCÃCH3).
/
6.91 (m, 14H, aromatic H); 6.10 (s, 1H, C5Á
/
Ind-
4.7. 2,7-Dibenzyl-9-[1-(inden-3-yl)-1-
methylethyl]fluorene (10)
/
Ind-sp3);
/
/
To an argon purged Schlenk tube was added 1.0 g (2.9
mmol) of 4 and 30 ml of dry Et2O. The solution was
cooled to 0 8C and 1.8 ml of a 1.6 M solution of
butyllithium in hexane (2.9 mmol) was added dropwise.
The solution was warmed to r.t. and stirred for 4 h.
Next, the solution was cooled to 0 8C and 0.45 g (2.9
mmol) of 2,3-benz-6,6-dimethylfulvene (6) was added.
Upon completion of the addition, the solution was
warmed to r.t. and stirred overnight. After hydrolysis
with aqueous NH4Cl, the organic layer was separated.
4.5. 2,7-Bis(2,4,-dimethylphenyl)-9-[1-(inden-3-yl)-1-
methylethyl]fluorene (8)
To an argon purged Schlenk tube was added 0.94 g
(2.5 mmol) of 2 and 30 ml of dry Et2O. The solution was
cooled to 0 8C and 1.56 ml of a 1.6 M solution of
butyllithium in hexane (2.5 mmol) was added dropwise.
The solution was warmed to r.t. and stirred for 4 h.
Next, the solution was cooled to 0 8C and 0.39 g (2.5
mmol) of 2,3-benz-6,6-dimethylfulvene (6) was added.
Upon completion of the addition, the solution was
warmed to r.t. and stirred overnight. After hydrolysis
with aqueous NH4Cl, the organic layer was separated.
The aqueous layer was extracted with 2ꢁ10 ml of Et2O
/
and the organic layers were combined. The resulting
organic solution was then dried with MgSO4, filtered,
and the solvent removed. The resulting yellow foam was
triturated with pentane and crystallized from acetone
resulting in 0.92 g (64%) of 10 as a light yellow solid,
The aqueous layer was extracted with 2ꢁ10 ml of Et2O
/
and the organic layers were combined. The resulting
organic solution was then dried with MgSO4, filtered,
and the solvent removed. The resulting yellow foam was
triturated with pentane and crystallized from acetone
resulting in 0.82 g (62%) of 8 as a light yellow solid, m.p.
m.p. 104Á
C39H34. Calc.: C, 93.18; H, 6.82%. H-NMR (CDCl3):
d 7.94Á6.91 (m, 20H, aromatic H); 5.89 (s, 1H, C5ÁInd-
sp2); 4.65 (s, 1H, C5-Fluorene); 3.91 (s, 4H, benzylic H);
3.06 (s, 2H, C5Á CÃCH3).
Ind-sp3); 1.14 (bs, 6H, CH3Ã
/
106 8C. Anal. Found: C, 93.01; H, 6.89
1
/
/
/
/
/
207Á
Calc.: C, 92.78; H, 7.22%. H-NMR (CDCl3): d 7.92Á
6.89 (m, 16H, aromatic H); 6.10 (s, 1H, C5Á
Ind-sp2);
4.86 (s, 1H, C5-Fluorene); 3.27 (s, 2H, C5Á
Ind-sp3); 2.13
(s, 6H, C6-CH3); 1.96 (s, 6H, C6-CH3); 1.25 (bs, 6H,
CH3ÃCÃCH3).
/
209 8C. Anal. Found: C, 92.88; H, 7.28 C41H38.
1
/
/
4.8. Dichloro[h5-1-indenyl(1-methylethylidene)-[2,7-
bis-(2,4,6-trimethylphenyl)-h5-9-fluorenyl]zirconium
(11)
/
/
/
To an argon purged Schlenk tube equipped with a
magnetic stir bar was added 0.500 g (0.89 mmol) of 7.
The solid was dissolved in 25 ml of dry Et2O and the
solution was cooled to 0 8C. A 1.6 M solution of n-BuLi
in hexane (1.12 ml, 1.79 mmol) was added dropwise via
4.6. 9-[1-(Inden-3-yl)-1-methylethyl]-2,7-bis-(2-
tolyl)fluorene (9)
To an argon purged Schlenk tube was added 1.0 g (2.9
mmol) of 3 and 30 ml of dry Et2O. The solution was
cooled to 0 8C and 1.8 ml of a 1.6 M solution of
butyllithium in hexane (2.9 mmol) was added dropwise.
The solution was warmed to r.t. and stirred for 4 h.
Next, the solution was cooled to 0 8C and 0.45 g (2.9
mmol) of 2,3-benz-6,6-dimethylfulvene (6) was added.
Upon completion of the addition, the solution was
warmed to r.t. and stirred overnight. After hydrolysis
with aqueous NH4Cl, the organic layer was separated.
syringe producing a yellowÁorange solution. The solu-
/
tion was allowed to warm to r.t. and was stirred for 8 h.
The solution was cooled again to 0 8C and 0.207 g (0.89
mmol) of ZrCl4 was added directly to the dianion
solution as a solid. The resulting suspension was stirred
overnight at r.t. yielding a bright orange precipitate.
Filtration of the Et2O solution followed by extraction of
the residue in CH2Cl2 produced a red solution with a
white suspension. Filtration of the suspension followed
by concentration of the solution to 5 ml and cooling to
The aqueous layer was extracted with 2ꢁ10 ml of Et2O
/
and the organic layers were combined. The resulting
organic solution was then dried with MgSO4, filtered,
and the solvent removed. The resulting yellow foam was
triturated with pentane and crystallized from acetone
resulting in 0.86 g (60%) of 9 as a light yellow solid, m.p.
ꢂ20 8C produced an orange solid. The solid was filtered
and dried in vacuo to give 0.13 g (19.7%) of 11. MS (EI)
Calc. for C43H40Cl2Zr: 718 Found: 718. 1H-NMR
/
(CDCl3): d 8.11Á6.80 (m, 14H, aromatic H); 6.44 (d,
/
1H, C5-Ind); 5.63 (d, 1H, C5-Ind); 2.35 (s, 6H, C6-CH3);
2.08 (s, 6H, C6-CH3); 2.04 (s, 6H, C6-CH3); 1.26 (s, 3H,
bridge CH3); 0.90 (s, 3H, bridge CH3).
144Á
/
145 8C. Anal. Found: C, 92.92; H, 6.93 C39H34.
1
Calc.: C, 93.18; H, 6.82%. H-NMR (CDCl3): d 7.82Á
/

J. Esteb et al. / Journal of Organometallic Chemistry 675 (2003) 97Á
/104
103
4.9. Dichloro[h5-1-indenyl(1-methylethylidene)-[2,7-
bis-(2,6-dimethylphenyl)-h5-9-fluorenyl]zirconium (12)
The solid was dissolved in 25 ml of dry Et2O and the
solution was cooled to 0 8C. A 1.6 M solution of n-BuLi
in hexane (1.12 ml, 1.79 mmol) was added dropwise via
To an argon purged Schlenk tube equipped with a
magnetic stir bar was added 0.472 g (0.89 mmol) of 8.
The solid was dissolved in 25 ml of dry Et2O and the
solution was cooled to 0 8C. A 1.6 M solution of n-BuLi
in hexane (1.12 ml, 1.79 mmol) was added dropwise via
syringe producing a yellowÁorange solution. The solu-
/
tion was allowed to warm to r.t. and was stirred for 8 h.
The solution was cooled again to 0 8C and 0.207 g (0.89
mmol) of ZrCl4 was added directly to the dianion
solution as a solid. The resulting suspension was stirred
overnight at r.t. yielding a bright orange precipitate.
Filtration of the Et2O solution followed by extraction of
the residue in CH2Cl2 produced a red solution with a
white suspension. Filtration of the suspension followed
by concentration of the solution to 5 ml and cooling to
syringe producing a yellowÁorange solution. The solu-
/
tion was allowed to warm to r.t. and was stirred for 8 h.
The solution was cooled again to 0 8C and 0.207 g (0.89
mmol) of ZrCl4 was added directly to the dianion
solution as a solid. The resulting suspension was stirred
overnight at r.t. yielding a bright orange precipitate.
Filtration of the Et2O solution followed by extraction of
the residue in CH2Cl2 produced a red solution with a
white suspension. Filtration of the suspension followed
by concentration of the solution to 5 ml and cooling to
ꢂ20 8C produced an orange solid. The solid was filtered
/
and dried in vacuo to give 0.122 g (20.6%) of 14. MS
1
(EI) Calc. for C39H32Cl2Zr: 662 Found: 662. H-NMR
(CDCl3): d 8.05Á6.96 (m, 20H, aromatic H); 6.48 (d,
/
1H, C5-Ind); 5.61 (d, 1H, C5-Ind); 3.24 (s, 4H, benzylic
H); 2.88 (s, 3H, bridge CH3); 2.47 (s, 3H, bridge CH3).
ꢂ
/
20 8C produced an orange solid. The solid was filtered
and dried in vacuo to give 0.082 g (13.4%) of 12. MS
1
(EI) Calc. for C41H36Cl2Zr: 690 Found: 690. H-NMR
4.12. Polymerization procedure
(CDCl3): d 8.14Á6.89 (m, 16H, aromatic H); 6.46 (d,
/
1H, C5-Ind); 5.87 (d, 1H, C5-Ind); 2.34 (s, 6H, C6-CH3);
2.09 (s, 6H, C6-CH3); 1.35 (s, 6H, bridge CH3); 1.04 (s,
3H, bridge CH3).
A 250 ml glass pressure bottle was sealed under an
argon atmosphere. Freshly distilled dry toluene (50 ml)
was added via syringe, and pressurized with the appro-
priate monomer (15 psi). A 4000-fold molar excess of
MAO was then added to the bottle, which was placed in
a water bath at the desired temperature and stirred for
4.10. Dichloro[h5-1-indenyl(1-methylethylidene)-[2,7-
bis-(2-methylphenyl)-h5-9-fluorenyl] zirconium (13)
10 min. The zirconium catalyst (2.5 mmol) in an MAOÁ
/
To an argon purged Schlenk tube equipped with a
magnetic stir bar was added 0.447 g (0.89 mmol) of 9.
The solid was dissolved in 25 ml of dry Et2O and the
solution was cooled to 0 8C. A 1.6 M solution of n-BuLi
in hexane (1.12 ml, 1.79 mmol) was added dropwise via
toluene solution was added and the mixture was stirred
magnetically until the desired reaction time was reached.
The reaction mixture was subsequently quenched with
2% HCl in methanol, filtered, and dried in a vacuum
oven at 70 8C.
syringe producing a yellowÁorange solution. The solu-
/
tion was allowed to warm to r.t. and was stirred for 8 h.
The solution was cooled again to 0 8C and 0.207 g (0.89
mmol) of ZrCl4 was added directly to the dianion
solution as a solid. The resulting suspension was stirred
overnight at r.t. yielding a bright orange precipitate.
Filtration of the Et2O solution followed by extraction of
the residue in CH2Cl2 produced a red solution with a
white suspension. Filtration of the suspension followed
by concentration of the solution to 5 ml and cooling to
4.13. Polymer analysis
Polymer melting points were determined by using a
Dupont Thermal Analyst DSC system at a heating rate
of 20 8C minꢂ1. Molecular weights were determined by
high temperature GPC in 1,2,4-trichlorobenzene at
135 8C.
ꢂ20 8C produced an orange solid. The solid was filtered
/
and dried in vacuo to give 0.125 g (21.2%) of 13. MS
1
(EI) Calc. for C39H32Cl2Zr: 662 Found: 662. H-NMR
Acknowledgements
(CDCl3): d 8.13Á6.88 (m, 18H, aromatic H); 6.53 (d,
/
1H, C5-Ind); 6.04 (d, 1H, C5-Ind); 2.35 (s, 6H, C6-CH3);
2.23 (s, 3H, bridge CH3); 1.96 (s, 3H, bridge CH3).
We would like to thank Dr G. Dabkowski for
microanalyses and Dr L.C. Dickinson for assistance
with 13C-NMR. Mass spectral data were obtained at the
University of Massachusetts Mass Spectrometry Facil-
ity, which is supported, in part, by the National Science
Foundation. We would also like to thank SOLVAY
Polyolefins Europe-Belgium for their financial support
of this research program.
4.11. Dichloro[h5-1-indenyl(1-methylethylidene)-[2,7-
dibenzyl-h5-9-fluorenyl]zirconium (14)
To an argon purged Schlenk tube equipped with a
magnetic stir bar was added 0.447 g (0.89 mmol) of 10.

104
J. Esteb et al. / Journal of Organometallic Chemistry 675 (2003) 97Á104
/
(b) J. Kukral, P. Lehmus, T. Feifel, C. Troll, B. Rieger,
Organometallics 19 (2000) 3767;
References
(c) U. Dietrich, M. Hackmann, B. Rieger, M. Klinga, M. Leskelae,
J. Am. Chem. Soc. 121 (1999) 4348;
[1] (a) E.J. Thomas, J.C.W. Chien, M.D. Rausch, Organometallics 18
(1999) 1439;
(d) G. Jany, R. Fawzi, M. Steimann, B. Rieger, Organometallics 16
(1997) 550.
(b) E.J. Thomas, J.C.W. Chien, M.D. Rausch, Organometallics 19
(2000) 4077;
[3] J.J. Esteb, J.C.W. Chien, M.D. Rausch submitted for publication.
[4] H.G. Alt, R. Zenk, J. Organomet. Chem. 522 (1996) 39.
[5] T. Stauner, L. Avar, L. Chardonnens, Helv. Chim. Acta 53 (1970)
1311.
(c) E.J. Thomas, J.C.W. Chien, M.D. Rausch, Organometallics 19
(2000) 5744;
(d) E.J. Thomas, J.C.W. Chien, M.D. Rausch, J. Organomet.
Chem. 631 (2001) 29.
[6] H.G. Alt, M. Jung, G. Kehr, J. Organomet. Chem. 562 (1998) 153.
[7] K.J. Stone, R.D. Little, J. Org. Chem. 49 (1984) 1849.
[2] (a) B. Rieger, J. Gerhard, R. Fawzi, M. Steinmann, Organome-
tallics 13 (1994) 647;