Synthesis, structure, and catalytic properties of ansa-zirconocenes, Me2Si(RInd)2ZrCl2 (R = 2-p- Or 3-p-tolyl)

Article abstract of DOI:10.1016/s0022-328x(98)00424-0

ansa-Ligands, Me₂Si(RInd)₂ [R = 2-p (1) and 3-p-tolyl (2)], have been prepared as a mixture of rac- and meso-isomers in a ratio of 1:1 from the reactions of Me₂SiCl₂ with cyanocuprates of 1-p-tolylindene and 2-p-tolylindene in diethyl ether, respectively. Pure rac-isomers, 1r and 2r, have been isolated by fractional recrystallization of 1 and 2. Thermal diastereomerization of 1 and 2 between rac- and meso-isomers has been studied by ¹H-NMR spectroscopy. These results imply that 1 and 2 undergo the diastereomerization process by migration of silicon moiety and hydrogen atom, respectively. ansa-Zirconocenes, Me₂Si(RInd)₂ZrCl₂ [R = 2-p (3) and 3-p-tolyl (4)], have been prepared from the reactions of the corresponding dilithiated ligands with ZrCl₄ in diethyl ether and hexane at -78°C. The molecular structure of rac-3 has been determined by a single crystal X-ray diffraction study. Propylene polymerization has been studied using rac-3 and meso-4 in the presence of methylaluminoxane (MAO). Catalyst rac-3 produces a highly isotactic polypropylene (PP) at 0°C by the enantiomorphic site control mechanism and meso-4 affords a syndiotactic dominant PP having a rr triad of 49% at - 30°C by the chain end control mechanism.

Full text of DOI:10.1016/s0022-328x(98)00424-0

Journal of Organometallic Chemistry 559 (1998) 149–156
Synthesis, structure, and catalytic properties of ansa-zirconocenes,
Me2Si(RInd)2ZrCl2 (R=2-p- or 3-p-tolyl)
Sung Cheol Yoon a, Je-Woo Park b, Hyun Sook Jung a, Hyunjoon Song a, Joon T. Park a,*,
Seong Ihl Woo b
a Department of Chemistry, Korea Ad6anced Institute of Science and Technology, Taejon, 305-701, South Korea
b Department of Chemical Engineering, Korea Ad6anced Institute of Science and Technology, Taejon, 305-701, South Korea
Received 18 November 1997; received in revised form 16 January 1998
Abstract
ansa-Ligands, Me2Si(RInd)2 [R=2-p (1) and 3-p-tolyl (2)], have been prepared as a mixture of rac- and meso-isomers in a ratio
of 1:1 from the reactions of Me2SiCl2 with cyanocuprates of 1-p-tolylindene and 2-p-tolylindene in diethyl ether, respectively. Pure
rac-isomers, 1r and 2r, have been isolated by fractional recrystallization of 1 and 2. Thermal diastereomerization of 1 and 2
between rac- and meso-isomers has been studied by 1H-NMR spectroscopy. These results imply that 1 and 2 undergo the
diastereomerization process by migration of silicon moiety and hydrogen atom, respectively. ansa-Zirconocenes,
Me2Si(RInd)2ZrCl2 [R=2-p (3) and 3-p-tolyl (4)], have been prepared from the reactions of the corresponding dilithiated ligands
with ZrCl4 in diethyl ether and hexane at −78°C. The molecular structure of rac-3 has been determined by a single crystal X-ray
diffraction study. Propylene polymerization has been studied using rac-3 and meso-4 in the presence of methylaluminoxane
(MAO). Catalyst rac-3 produces a highly isotactic polypropylene (PP) at 0°C by the enantiomorphic site control mechanism and
meso-4 affords a syndiotactic dominant PP having a rr triad of 49% at −30°C by the chain end control mechanism. © 1998
Elsevier Science S.A. All rights reserved.
Keywords: ansa-Zirconocene; Tolylindene; Diastereomerization; Propylene polymerization; Crystal structure
1. Introduction
y-ligands during polymerization [6,7]. Waymouth and
coworkers [7] have reported that unbridged (2-
PhInd)2ZrCl2 (Ph=C6H5) catalyst precursor polymer-
izes propylene to yield atactic-isotactic stereoblock
polymers with elastomeric properties by a facile inter-
conversion of the rotameric conformers of the catalyst.
The introduction of a bridging group between the two
y-ligands restricts the mobility of the y-ligands provid-
ing a rigid system which transfers the chirality informa-
tion of the ansa-metallocene onto the growing polymer
chain by the enantiomorphic site controlled process.
Spaleck and coworkers [2] have reported that Me2Si-
bridged zirconocenes, Me2Si(p5-2,4-R2Ind)2ZrCl2 with
2-methyl and 4-aromatic groups substituted, are new
optimized metallocene catalysts for isotactic propylene
polymerization. The Me2Si-bridge in ansa-metallocene
The development of homogeneous metallocene based
catalysts for h-olefin polymerization has led to the
tailored polymer synthesis with enhanced properties by
a rational design of metallocene complexes. For exam-
ple, C2-symmetric ansa-metallocene catalysts produce
isotactic polypropylene (iPP) [1–4] and Cs-symmetric
ansa-metallocene yield syndiotactic polypropylene
(sPP) [5]. The bis(indenyl) ligand and its derivatives
with proper substituents have been considerably em-
ployed as y-ligands of metallocenes. Unbridged mono-
substituted indenyl complexes have shown their
versatile catalytic properties caused by a rotation of
* Corresponding author. Fax: +82 42 8692810.
0022-328X/98/$19.00 © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00424-0

150
S. Cheol Yoon et al. / Journal of Organometallic Chemistry 559 (1998) 149–156
Scheme 1.
catalysts appears to be preferable over Me2C- or two
atom ethylene bridge, imposing high rigidity and favor-
able steric and electronic characteristics to ansa-metal-
locenes to produce high isotacticity and high molecular
weight of polymers.
lithium salt of the substituted indene with Me2SiCl2.
However, use of the corresponding cyanocuprate
reagent [12] of the substituted indene results in better
yields of a mixture of rac- and meso-isomers in a ratio
of 1:1 for both 1 (83%) and 2 (77%) as shown in
1
In previous work, we reported the synthesis of un-
bridged metallocene complexes, rac- and meso-(1-
Scheme 1. H-NMR spectra of 1 and 2 are consistent
with the previous observation that the substitution of Si
on indene occurs exclusively at the 1-position of the
indene [2,3]. Pure rac-isomers, 1r and 2r, could be
isolated by recrystallization of 1 and 2 in diethyl ether
and hexane at −20°C, respectively.
The ansa-zirconocenes, 3 (67%, r:m=2:1) and 4
(51%, r:m=1:1), were obtained from the reactions of
the dilithio salts of 1 and 2 with zirconium tetrachloride
in diethyl ether and hexane at −78°C, respectively.
TolInd)2ZrCl2
(Tol=p-C6H4CH3),
and
their
polymerization behaviors [8]. Recently we also reported
synthesis, structure and catalytic properties of ansa-zir-
conocenes Me2X(Cp)(RInd)ZrCl2 (X=C, Si; R=2-p-
or 3-p-tolyl) [9]. As an extension of our studies in this
area, we prepared Me2Si-bridged ansa-ligands
Me2Si(RInd)2 (R=2-p- (1) or 3-p-tolyl (2)) and their
zirconocene complexes Me2Si(RInd)2ZrCl2 (R=2-p-
(3) or 3-p-tolyl (4)). The two ansa-ligands undergo
thermal diastereomerization between rac- and meso-iso-
mers as was observed previously for Me2Si(Ind)2 by
Chien [10] and McGlinchey [11]. We herein report
details of synthesis of ansa-ligands, 1 and 2, and their
thermal diastereomerization in solution. Furthermore,
we describe synthesis of ansa-zirconocenes, 3 and 4,
and structural characterization of rac-3, together with
the results of propylene polymerization with 3 and
4/MAO catalyst systems.
Fractional recrystallization of
3
and
4
in
dichloromethane at −20°C gave pure rac (3r) and
meso (4m) isomers as orange crystals. The 1H-NMR
spectra of 1r–4r (C2 symmetry) show a single methyl
resonance for the two enantiotopic methyl groups on
the silicon atom, whereas those of 1m–4m (Cs symme-
try) exhibit a pair of singlets for the two diastereotopic
methyl groups.
2.2. Diastereomerization of ansa-ligands, 1 and 2
The |-indenyl derivatives of silicon moiety are well
known to be fluxional by migration of either hydrogen
atom or silicon moiety [13]. Thermal diastereomeriza-
tion of rac-Me2Si(Ind)2 (5r) to meso-isomer (5m) has
been studied, and symmetry-forbidden 1, 3-metal-
lotropic shifts has been proposed as a possible mecha-
nism for the process by Chien and coworkers [10].
McGlinchey and coworkers recently reported that the
diastereomerization of 5r?5m proceeds by successive
symmetry-allowed [1,5]-suprafacial sigmatropic shifts of
2. Results and discussion
2.1. Preparation of 1–4
The p-tolyl substituted indenes, 1-p-tolylindene and
2-p-tolylindene, were prepared by the procedures de-
scribed in the literature [9]. The ansa-ligands,
Me2Si(RInd)2 (R=2-p-tolyl (1); R=3-p-tolyl (2)),
could be prepared from the reaction of 2 equiv. of the

S. Cheol Yoon et al. / Journal of Organometallic Chemistry 559 (1998) 149–156
151
Table 1
Kinetic and thermodynamic data in toluene-d8
t (°C)
Keq
103kobs
103k1
103k−1
(min−1
)
(min−1
)
(min−1
)
75
80
85
90
95
1.0790.01
1.1090.01
1.1190.01
1.1290.01
1.1390.01
5.890.3
12.890.6
18.290.3
33.092.1
54.791.4
3.090.2
6.790.3
9.690.2
17.591.2
29.090.9
2.890.1
6.190.3
8.690.1
15.590.9
25.790.5
Scheme 2.
one Me2Si(Ind) moiety over the surface of the five-
membered ring of the other indenyl unit as depicted in
Scheme 2 [11]. Furthermore, they isolated the iso-in-
dene intermediate which has been trapped as its double
Diels-Alder adduct with tetracyanoethylene (TCNE).
The diastereomerization process of 1r?1m and
2r?2m was studied by 1H-NMR spectroscopy. 1H-
NMR spectra of 1r were recorded in the temperature
range from 75 to 95°C in toluene-d8. Typical time-re-
solved 1H-NMR spectra of 1r at 80°C are shown in Fig.
1. As the intensities of the resonances of 1r decrease,
the resonances corresponding to 1m increase in inten-
sity. Relative concentrations of the two diastereomers
were measured by integration of the peaks due to the
Me2Si group at l −0.86 for 1r and at l −0.75 and
−0.84 for 1m. Analyses according to reversible first-or-
der kinetics give excellent fits of experimental data. The
kinetic and thermodynamic data are listed in Table 1.
The plot of ln Keq vs 1/T (correlation coefficient,
0.9444) yields DHo=0.6790.01 kcal mol−1 and
DSo=2.190.8 cal K−1 mol−1 for the process, 1r“
1m. Activation parameters derived from the Eyring
plots of ln(k1/T) vs 1/T and ln(k−1/T) vs 1/T (correla-
tion coefficients, 0.9807 and 0.9815, respectively) are
DH‡1=25.990.6 kcal mol−1 and DS‡1=4.492.5 cal
K−1 mol−1 for the forward isomerization 1r“1m and
DH−‡ 1=25.290.6 kcal mol−1 and DS−‡ 1=2.291.3
cal K−1 mol−1 for the reverse isomerization 1m“1r.
Thermodynamic and kinetic data for 1 and 5 are com-
pared in Table 2. Enthalpy (DHo) of the diastereomer-
ization process for
1 is smaller than that for
unsubstituted indenyl compound 5, whereas activation
parameter DH‡1 is larger compared to 5. These data
imply that 1r and 1m have a similar thermal stability
and the 2-p-tolyl substituent of the indenyl ligand in 1
has an influence on the diastereomerization process
resulting in an increase of the activation energy for the
silyl migration. We attempted a Diels-Alder reaction of
1r with TCNE, but could not obtain the iso-indene
intermediate of 1r.
Fig. 1. Time-resolved 1H-NMR Spectra of 1r and 1m at 80°C in toluene-d8.

152
S. Cheol Yoon et al. / Journal of Organometallic Chemistry 559 (1998) 149–156
Table 2
Comparision of thermodynamic and activation parameters for 1 and 5
Diastereomerization
DHo (kcal mol−1
)
DSo (cal mol−1 K−1
)
DH‡1 (kcal mol−1
)
DS‡1 (cal mol−1 K−1
)
ref.
1r“1m
5r“5m
0.6790.01
7.7
2.190.8
20.7
25.990.6
21.990.5
4.492.5
−7.291.4
this work
[10,11]
In case of 2r, no 1H-NMR spectral change was
observed between 75 and 95°C for several hours. After
2 days at 100°C, however, there appeared additional
resonances indicating formation of 2m. The [1,5]-hydro-
gen shifts has been proposed to explain the formation of
3-silyl isomer of 5, and is known to occur at elevated
temperatures (\150°C) after prolonged heating [13,14].
It is, therefore, considered that the slow diastereomeriza-
tion process of 2r“2m at high temperature is due to the
hydrogen migration. In order to elucidate the hydrogen
migration during the diastereomerization of 2r?2m,
1,1%-deuterium substituted 2 (2d) was prepared by
quenching the reaction mixture of 2 and n-BuLi with
D2O. The signal at l 3.72 due to the hydrogen (Ind-H-1)
on the carbon-1 of both 2r and 2m is absent in the
1H-NMR spectrum of 2d (see the bottom spectrum
of Fig. 2). When compound 2d was heated at 110°C
for prolonged periods, the signal at l 3.72 due to
Ind-H-1 grows in and the intensity of the two reson-
ances due to the Ind-H-2 of 2r and 2m decreases (see
Fig. 2). This observation implies that the diastereo-
merization of 2 occurs by the hydrogen shift as shown
in Scheme 3.
2.3. Crystal structure of 3r · CHCl3
The crystal contains an ordered arrangement of dis-
crete Me2Si(2-TolInd)2ZrCl2 · CHCl3 molecules, which
are mutually separated by normal van der Waals dis-
tances. The CHCl3 solvate molecule does not enter into
any significant interaction with molecule 3r. The overall
molecular geometry and the atomic labelling scheme of
3r is illustrated in Fig. 3. Details of the crystallographic
data and selected bond distances and angles are shown
in Tables 3 and 4, respectively. The overall structure of
3r is similar to that previously reported for rac-Me2Si(2-
MeInd)2ZrCl2 [4] and rac-Me2Si(2-Me2NInd)2ZrCl2 [15].
Complex 3r has a crystallographically imposed C2 sym-
metry with Zr and Si atoms on the C2 axis. Complex 3r
adopts a distorted tetrahedral coordination in which the
Ind(Cen)–Zr–Ind(Cen) angle is 127.7 (3)° and the Cl–
Zr–Cl bond angle is 94.25 (3)°. The Zr–Cl bond lengths
˚
are 2.427 (2) and 2.425 (2) A. The Zr–Ind (Cen) lengths
˚
are 2.229 (7) and 2.246 (7) A. The Zr–C and Zr–Cl
distances as well as Ind(Cen)–Zr–Ind(Cen) and Cl–Zr–
Cl angles are comparable to those observed for the two
known complexes. The dihedral angle between the two
indenyl rings is 62.9 (3)° and those between the indenyl
and the p-tolyl ring are 48.4 (3) and 57.4 (3)°.
2.4. Propylene polymerization
Polymerization of propylene with complexes 3r and 4m
in the presence of MAO was carried out in toluene in the
temperature range of −30ꢀ50°C. The results are sum-
marized in Table 5 with those of previously known
catalyst, meso-(1-TolInd)2ZrCl2 (6m) [8]. The optimum
activity for 3r is observed at 25°C, but the activity
decreases drastically at 0°C. Similarly, catalyst system 4m
exihibits a considerable decrease in catalytic activity with
decreasing polymerization temperature.
Fig. 2. Time-resolved 1H-NMR Spectra of 2d at 110°C in toluene-d8.
Scheme 3.

S. Cheol Yoon et al. / Journal of Organometallic Chemistry 559 (1998) 149–156
153
Fig. 3. Molecular structures of 3r with atomic numbering scheme (left). Projection perpendicular to ZrCl(1)Cl(2) plane (right).
The stereoregularity of PP produced with 3r and 4m
has been investigated by 13C-NMR spectroscopy. The
catalyst 3r produces isotactic PP with an mm triad
intensity of 91% at 0°C. The triad distribution of
catalyst 3r follows the enantiomorphic site control
propagation statistics (2(rr)/(mr)=1.0), indicating that
the isotactic portion of the polymer was controlled by
the chirality of catalyst [16]. As shown in Fig. 3, the
p-tolyl group in 3r is oriented toward the lateral sector
of the bent metallocene wedge, which consequently has
little influence on enantiofacial coordination of the
incoming propylene monomer to produce iPP.
syndiotactic stereosequence (see Table 5). Complex 4m,
a bridged analogue of 6m, also affords a syndiotactic
dominant PP. The 13C-NMR spectrum of the PP with
4m is consistent with the Bernoullian propagation
statistics (4(mm)(rr)/(mr)2=1.0) for the chain end con-
trolled stereospecific polymerization [16]. The catalyst
6m has shown complete loss of the syndiotacticity of
the polymer with increasing polymerization tempera-
ture, whereas the syndiotacticity of PP with catalyst 4m
remains comparable in the temperature range of −
30ꢀ25°C. This result indicates that the presence of a
bridging group renders the rigidity of y-ligands to
catalysts, producing a stereospecific polymer without a
significant temperature effect.
We previously described that the unbridged metal-
locene 6m affords PP at −30°C having dominantly a
Table 3
Crystallographic data for complex 3r · CHCl3
3. Experimental section
Formula
fw
C35H30Cl5SiZr
748.2
3.1. General comments
Crystal system
Space group
Triclinic
P-1
12.912 (2)
15.773 (4)
9.280 (1)
99.18 (2)
99.95 (1)
113.75 (2)
1647.9 (5)
2
1.508
298
0.07×0.5×0.3
Graphite-monochromated Mo–Kh
0.80
ꢀ/2q
47.8
All reactions were carried out under an inert atmo-
sphere of argon by using either standard Schlenk or
glovebox techniques. Tetrahydrofuran (THF), diethyl
ether, hexane and toluene were distilled from sodium-
˚
a (A)
˚
b (A)
˚
c (A)
h (°)
i (°)
k (°)
Table 4
Selected bond distances and bond angles for 3r with estimated
standard deviations
3
˚
V (A )
Z
Dcalcd (g cm−3
Temp (K)
)
˚
Bond distances (A)
Zr–Cl(1)
Zr–Cl(2)
Zr–C(1)
Zr–C(2)
Zr–C(3)
Zr–C(4)
Zr–C(9)
Zr–C(17)
2.427(2)
2.425(2)
2.472(7)
2.553(8)
2.554(8)
2.604(8)
2.507(8)
2.481(7)
Zr–C(18)
Zr–C(19)
Zr–C(20)
Zr–C(25)
Si–C(1)
2.554(8)
2.598(8)
2.623(8)
2.512(8)
1.887(8)
1.889(8)
2.229(7)
2.246(7)
Crystal size (mm)
Radiation
v (mm−1
)
scan mode
2qmax (°)
No. of unique reflns
No. of reflns (I\3|(I))
Si–C(17)
5156
2820
499
0.045
0.051
0.58
Zr–Ind(Cen)a
Zr–Ind(Cen)
No. of params
Ra
Bond angles (°)
Rwb
Cl(1)–Zr–Cl(2) 94.2 5(3)
C(1)–Si–C(17) 94.5(3)
C(33)–Si–C(34) 105.7(5)
Ind(Cen)–Zr–Ind(Cen) 127.7(3)
Ind–Indb
62.9(3)
GOF
a R=SꢀFoꢁ−ꢁFoꢀ/ꢁFoꢁ,
b Rw=[S(ꢁFoꢁ−ꢁFcꢁ)2/SꢁFoꢁ ]
,
a Cen=ring centroid.
2 1/2
c GOF=[S(ꢁFoꢁ−ꢁFcꢁ)2/(No. of reflns–No. of params)]1/2
.
b Interplanar angle between the two indenyl ligands.

154
S. Cheol Yoon et al. / Journal of Organometallic Chemistry 559 (1998) 149–156
Table 5
Polymerizationa of propylene with 3r and 4m/MAO catalyst systems
Metallocenes Zr (mmol) MAO (mmol) Tp (°C) tp (h) Yield (g) Ab
Mw (×10−3
)
MWD mm mr
rr
Ref.
(
3r
15
15
15
15
15
30
50
25
0
1.2
1
1
4.00
6.90
1.06
190.5
383.3
59.0
0.37 0.38 0.25 This work
0.70 0.20 0.10
0.91 0.07 0.02
1.3
4.4
1.72
1.68
4m
6m
20
20
20
40
40
40
25
0
−30
5
5
5
15.15
7.40
0.84
126.3
61.7
7.0 15.1
147.9
104.2 37.8
0.15 0.45 0.40 This work
0.08 0.48 0.44
0.11 0.44 0.45
3.6
2.22
2.17
8
16
40
40
25
−30
2
6
2.84
12.00
0.30 0.47 0.23 [8]
0.09 0.42 0.49
2.52
a Polymerization conditions: 1.2 atm, toluene (250 ml).
b Activity in (kg of PP)/((mol of Zr) [monomer] h).
benzophenone under N2 atmosphere. Dichloro-
methane was refluxed over CaH2 and then distilled
under N2 atmosphere. Silica gel (Merck, 230-400
mesh) was used for column chromatography. 1-p-
Tolylindene and 2-p-tolylindene were prepared by the
preparative TLC (hexane) to afford 1 (0.71 g, 1.5
mmol, 83%) as a pale yellow powder (r/m ratio, 1:1).
Fractional recrystallization from diethyl ether at −
20°C afforded pure 1r (0.30 g, 0.64 mmol, 35%) as a
colorless powder. Isomer 1m was obtained from the
filtrate as a pale yellow oil after removal of the sol-
1
procedures reported previously [9]. The H-NMR and
13C-NMR spectra were obtained on a Bruker AC-200
or AM-300 FT-NMR spectrometer. Mass spectra
were recorded on a JEOL SX 102 spectrometer. All
m/z values are referenced to 28Si and 35Cl. Microana-
lytical data were provided by the Analytical Labora-
tory of the Korea Basic Science Institute Seoul
Branch.
vent. Compound 1r: H-NMR (CDCl3, 25°C) l 7.56–
1
7.02 (18H, m, C6 indenyl and tolyl), 4.42 (2H,
H–C(1)), 2.30 (6H, s, tolyl CH3), −0.94 (6H, s,
Si(CH3)2). MS (70 eV): m/z 468 (M+). Anal. Calcd
for C34H32Si: C, 87.13; H, 6.88. Found: C, 87.37; H,
8.17. Compound 1m: 1H-NMR (CDCl3, 25°C): l
7.55–7.01 (18H, m, C6 indenyl and tolyl), 4.22 (2H,
H–C(1)), 2.33 (6H, s, tolyl CH3), −0.81 (3H, s,
Si(CH3)2), −1.02 (3H, s, Si(CH3)2).
Molecular masses were determined by gel perme-
ation chromatography on a Waters 150CV+ instru-
ment in 1,2,4-trichlorobenzene at 135°C. The
13C-NMR (75 MHz) spectra of the resulting polymers
were recorded at 100°C on a Bruker AMX-300 FT-
NMR spectrometer. The polymer samples were dis-
solved in 1,2,4-trichlorobenzene/benzene-d6 (4/1 by
vol.) up to a concentration of 15 wt.% at 130°C in
NMR tubes (10 mm o.d.).
3.3. Preparation of bis(3-p-tolylindenyl)dimethylsilane
(2)
1-p-Tolylindene (1.85 g, 9.0 mmol), copper cyanide
(0.024 g, 0.3 mmol), n-butyllithium (1.6 M, 6.2 ml,
10.0 mmol) and dichlorodimethylsilane (0.58 g, 4.5
mmol) were treated by a procedure similar to that for
the preparation of 1, producing 2 (1.61 g, 3.4 mmol,
77%) as an orange oil (r/m ratio, 1:1). Fractional
recrystallization of 2 from hexane at −20°C afforded
pure 2r (0.63 g, 1.3 mmol, 30%) as a colorless pow-
der. Isomer 2m was collected from the filtrate as an
orange oil after evaporation of the solvent. Com-
3.2. Preparation of bis(2-p-tolylindenyl)dimethylsilane
(1)
A 500 ml Schlenk flask was charged with 2-p-
tolylindene (0.75 g, 3.6 mmol), copper cyanide (0.01
g, 0.11 mmol), and diethyl ether (30 ml). To the mix-
ture was added dropwise a solution of n-butyllithium
(1.6 M, 2.5 ml, 4.00 mmol) at −20°C. After the
addition was complete, the reaction mixture was al-
lowed to warm up to room temperature for 2 h.
Then a solution of dimethyldichlorosilane (0.24 ml,
2.00 mmol) in THF (10 ml) was added dropwise at
room temperature. The resulting mixture was stirred
overnight and treated with a saturated solution of
NH4Cl in water (100 ml). The solution was extracted
with diethyl ether and dried over anhydrous magne-
sium sulfate. The crude product was purified with
1
pound 2r: H-NMR (CDCl3, 25°C) l 7.66–7.23 (16H,
m, C6 indenyl and tolyl), 6.63 (2H, d, J=2.1 Hz,
H–C(2)), 3.72 (2H, d, J=2.1 Hz, H–C(1)), 2.41 (6H,
s, tolyl CH3), −0.21 (6H, s, Si(CH3)2). MS (70 eV):
m/z 468 (M+). Anal. Calcd for C34H32Si: C, 87.13;
H, 6.88. Found: C, 88.48; H, 8.52. Compound 2m:
1H-NMR (CDCl3, 25°C): l 7.56–7.19 (16H, m, C6
indenyl and tolyl), 6.41 (2H, d, J=2.1 Hz, H–C(2)),
3.72 (2H, d, J=2.1 Hz, H–C(1)), 2.39 (6H, s, tolyl
CH3), −0.20 (3H, s, Si(CH3)2), −0.40 (3H, s,
Si(CH3)2).

S. Cheol Yoon et al. / Journal of Organometallic Chemistry 559 (1998) 149–156
155
3.4. Preparation of bis(3-p-tolylindenyl)
dimethylsilane-1,1%-d2 (2d)
3.7. Preparation of dimethylsilanediylbis(3-p-tolylin-
denyl)zirconium dichloride (4)
To a solution of 2 (0.9 g, 1.9 mmol) in diethyl ether
(30 ml) was added n-butyllithium (1.47 M, 2.7 ml, 3.9
mmol) in hexane at −78°C. The reaction mixture was
allowed to warm up to room temperature for 3 h,
treated with D2O (0.7 ml, 38.4 mmol), and dried over
anhydrous magnesium sulfate. The resulting suspension
was filtered and the filtrate was evaporated in vacuo.
The crude product was purified with preparative TLC
(hexane) to give 2d (0.72 g, 1.5 mmol, 80%) as an
Compound 2 (1.61 g, 3.43 mmol), n-butyllithium
(1.27 M, 5.54 ml, 7.03 mmol), and zirconium tetrachlo-
ride (0.80 g, 3.43 mmol) were treated as described for
the preparation of 3, providing orange compound 4
(1.00 g, 1.6 mmol, 51%) as a 1:1 mixture of the rac- and
meso-isomers.
Fractional
crystallization
from
dichloromethane at −20°C produced pure 4m (0.39 g,
1
0.62 mmol, 20%). Compound 4m: H-NMR (CDCl3,
25°C): 7.78–6.92 (16H, m, indenyl and tolyl), 5.96 (2H,
s, C5 indenyl) 2.30 (6H, s, tolyl CH3), 1.43 (3H, s,
Si(CH3)2), 0.94 (3H, s, Si(CH3)2). MS (70 eV): m/z 628
(M+). Compound 4r (data obtained from an isomeric
1
orange oil. H-NMR (CDCl3, 25°C): l 7.67–7.24 (16H,
m, C6 indenyl and tolyl), 6.63 (1H, s, H–C(3)), 6.43
(1H, s, H–C(3)), 2.42 (3H, s, tolyl CH3), 2.41 (3H, s,
tolyl CH3), 0.08 (3H, s, Si(CH3)2), −0.21 (3H, s,
Si(CH3)2), −0.41 (3H, s, Si(CH3)2) for an isomeric
mixture. MS (70 eV): m/z 470 (M+).
1
mixture): H-NMR (CDCl3, 25°C): l 7.80–7.00 (16H,
m, indenyl and tolyl), 6.14 (2H, s, C5 indenyl) 2.32 (6H,
s, tolyl CH3), 1.16 (6H, s, Si(CH3)2).
1
3.5. H-NMR study of diastereomerization of 1r to 1m
3.8. X-ray data collection and structure solution of
3r · CHCl3
A colorless powder of compound 1r (ca. 5 mg) was
transfered to five 5-mm NMR tubes and toluene-d8 (0.5
ml) was added to each NMR tube under the atmo-
sphere of nitrogen. The tubes were sealed, then heated
in an NMR probe at 75, 80, 85, 90, and 95°C, and
Crystals of 3r suitable for an X-ray analysis were
obtained by slow crystallization from chloroform at
−20°C. An orange crystal of the appropriate dimen-
sions was sealed under N2 in a thin walled glass capil-
lary. Preliminary examination and data collection were
performed using an Enraf-Nonius CAD4 diffractome-
ter equipped with a graphite monochromated Mo–Kh
radiation at 298 K. Relevant crystallographic data are
summarized in Table 2. Orientation matrices and unit
cell parameters were determined by least-square method
of 25 reflections with 22.76BqB28.06°. Intensity data
for 5165 independent reflections in the range −145
h513, 05k518, −105l510 were collected using
ꢀ/2q scan mode, ꢀ scan angle=(0.8+0.35 tan q)°,
2qmax=45°. Three standard reflections were monitored
every 3 h, which revealed no significant decay over the
course of data collection. Lorentz and polarization
corrections were applied to the intensity data. All the
calculations were carried out using the NRCVAX soft-
ware package [17]. The structure was solved by direct
and different Fourier methods and refined by the full
matrix least-squares methods employing unit weights.
All nonhydrogen atoms were refined anisotropically,
while hydrogen atoms were refined isotropically. Final
reliability factors for 2820 unique observed reflections
[Fo\3|(Fo)] were Rf=0.045 and Rw=0.051. The large
shift/esd was 0.269, and the maximum and minimum
hole in the final difference map were 0.85 and −0.44
1
monitored periodically by H-NMR spectroscopy.
3.6. Preparation of dimethylsilanediylbis(2-p-
tolylindenyl)zirconium dichloride (3)
A solution of n-butyllithium (1.36 M, 2.5 ml, 3.4
mmol) in hexane was added to a solution (40 ml) of 1
(0.76 g, 1.6 mmol) in diethyl ether and hexane at
−78°C. During warming to room temperature for 2 h
the reaction mixture changed from a red-orange to a
pink suspension. The pink suspension was added to a
suspension of zirconium tetrachloride (0.46 g, 1.99
mmol) in diethyl ether (10 ml) and hexane (10 ml) at
−78°C. Immediately after the addition the cooling
bath was removed. The suspension was stirred
overnight. The orange precipitate formed was filtered
and washed three times with diethyl ether (3×10 ml).
The orange solid was extracted with dichloromethane
(20 ml) and the extract was evaporated to give red-or-
ange compound 3 (0.69 g, 1.1 mmol, 67%) as a 2: 1
mixture of the rac- and meso-isomers. Fractional crys-
tallization from dichloromethane at −20°C afforded
pure 3r (0.39 g, 0.62 mmol, 38%). Compound 3r:
1H-NMR (CDCl3, 25°C): l 7.58–6.66 (18H, m, indenyl
and tolyl), 2.40 (6H, s, tolyl CH3), 0.87 (6H, s,
Si(CH3)2). MS (70 eV): m/z 628 (M+). Compound 3m
(data obtained from an isomeric mixture): 1H-NMR
(CDCl3, 25°C): l 7.73–6.84 (18H, m, indenyl and
tolyl), 2.23 (6H, s, tolyl CH3), 1.51 (3H, s, Si(CH3)2),
0.51 (3H, s, Si(CH3)2).
eA−3. Atomic coordinates for the non-hydrogen atoms
˚
are listed in Table 6.
3.9. Polymerization procedure
Solution polymerization reactions in toluene were

156
S. Cheol Yoon et al. / Journal of Organometallic Chemistry 559 (1998) 149–156
Table 6
puter program for the gas–liquid phase equilibria based
on Chao-Sender correlations. After polymerization was
terminated by injecting ethanol, the resulting polymer
was quenched with an excess of acidified methanol (ca.
five times of the amount of toluene used). The precipi-
tated polymer was separated from the polymerization
medium by cooling to −30°C, washed with fresh
ethanol, and dried in vacuo.
Atomic coordinates and equivalent isotropic displacement coefficients
2
(A ×102) for 3r · CHCl3
˚
Atom
x
y
z
Ueqa
Zr
0.2781(1)
0.3506(2)
0.2597(2)
0.2207(2)
0.3575(6)
0.4387(7)
0.4954(7)
0.4631(6)
0.5022(7)
0.4545(8)
0.3650(8)
0.3241(8)
0.3738(7)
0.4738(7)
0.4972(8)
0.5453(8)
0.5754(8)
0.552(1)
0.7932(1)
0.7354(2)
0.9177(2)
0.7232(2)
0.8104(5)
0.7903(6)
0.8672(7)
0.9404(6)
1.0347(6)
1.0888(7)
1.0547(6)
0.9661(6)
0.9050(6)
0.7134(6)
0.6867(7)
0.6249(7)
0.5853(7)
0.6109(8)
0.6734(7)
0.518(1)
0.6894(6)
0.7410(6)
0.7141(6)
0.6394(6)
0.5805(6)
0.5130(7)
0.4994(6)
0.5545(6)
0.6252(6)
0.8018(6)
0.8877(7)
0.9345(8)
0.8987(8)
0.8112(9)
0.7659(7)
0.953(1)
0.0759(1)
2.05(4)
2.9(1)
3.1(1)
2.2(1)
2.1(4)
2.4(4)
2.7(5)
2.4(4)
3.0(5)
3.1(5)
3.0(5)
2.8(4)
2.5(4)
2.8(4)
3.3(5)
3.9(6)
3.7(5)
4.4(6)
3.9(6)
7.0(1)
2.4(4)
2.5(4)
2.4(4)
2.7(4)
2.8(4)
3.2(5)
2.8(4)
2.8(4)
2.1(4)
2.7(4)
3.2(5)
4.5(6)
4.2(6)
4.3(6)
3.1(5)
6.0(1)
3.6(6)
3.2(6)
Cl(1)
Cl(2)
Si
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
−0.1239(2)
−0.0337(2)
0.3854(2)
0.3467(8)
0.2760(9)
0.2143(9)
0.2546(8)
0.233(1)
Acknowledgements
We are grateful to the Korea Academy of Industrial
Technology for the financial support of this work.
0.291(1)
0.363(1)
0.3854(9)
0.3350(8)
0.2802(9)
0.415(1)
0.427(1)
0.305(1)
0.173(1)
0.160(1)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(28)
C(29)
C(30)
C(31)
C(32)
C(33)
C(34)
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0.5043(9)
0.628(2)
0.322(3)
0.1274(7)
0.0730(7)
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−0.167(2)
0.227(1)
0.212(1)
0.295(1)
0.327(1)
0.273(1)
0.346(2)
0.446(1)
0.531(1)
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0.7807(8)
0.171(1)
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carried out at a propylene pressure of 1.2 atm, agitating
with a Teflon magnetic spinbar in a 500 ml glass
reactor. Toluene (200 ml) was introduced into the reac-
tor, temperature was increased to the polymerization
temperature, and then toluene was saturated with
propylene. A toluene solution of the Zr catalyst and
MAO purchased from Toso-Akzo as a toluene solution
was injected into the reactor by a tuberculin syringe,
and polymerization was started. Propylene concentra-
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.