Indenyl-amido titanium and zirconium dimethyl complexes: Improved synthesis and use in propylene polymerization

Article abstract of DOI:10.1016/S0022-328X(02)01853-3

The synthesis of a series of indenyl amido titanium dimethyl complexes, by means of the direct synthesis from the ligand, a 2-fold excess of MeLi, and TiCl₄ is reported. The ¹H NMR spectra of the complexes show a quartet structure for the metal-bound methyl groups, due to through-metal proton-proton coupling. Coupling of Ti-methyl protons with protons on the Cp ring is also revealed by COSY 2D-NMR. The performance of the Ti complexes in propylene polymerization, including [Me₂Si(Me₄C₅)(t-BuN)]TiMe₂ (1-TiMe₂), [Me₂Si(Ind) (t-BuN)]TiMe₂(2-TiMe₂) and six other methyl titanium complexes bearing substituted indenyl ligands, has been investigated with different cocatalysts and at different polymerization temperatures and propylene concentrations. All complexes produce amorphous polypropylene (am-PP). The catalytic activity and molecular weight strongly depend on the substitution of the Cp ring: 2-TiMe₂ gives polymers of lower molecular weight, while the presence of a methyl group in position 2 (as in 3-TiMe₂) determines up to 4-fold increase in molecular weight. The type of cocatalyst influences mainly the catalytic activity, the borates being better activators than MAO, but also molecular weight, with again the borates giving higher molecular weights than MAO. ΔΔE^? 2-TiMe₂ = 3.4 kcal mol^-1, ΔΔE^? 5-TiMe₂ = 3.8 kcal mol^-1, ΔΔE? 3-TiMe₂ = 6.3 kcal mol^-1. Even if all the polymers produced are amorphous, 2-TiMe₂ and 5-TiMe₂ show a microstructure unbalanced towards isotacticity, while 3-TiMe₂, 6-TiMe₂ and 8-TiMe₂ are syndiotactic-enriched. Chiral induction comes mainly from a weak enantiomorphic site control.

Full text of DOI:10.1016/S0022-328X(02)01853-3

Journal of Organometallic Chemistry 664 (2002) 5ꢁ26
/
www.elsevier.com/locate/jorganchem
Indenyl-amido titanium and zirconium dimethyl complexes:
improved synthesis and use in propylene polymerization
Luigi Resconi a,ꢀ, Isabella Camurati a, Cristiano Grandini a,1, Marilisa Rinaldi a,2,
Nicoletta Mascellani b, Orazio Traverso b
a Basell Polyolefins, Centro Ricerche G. Natta, CER 158 P.le G. Donegani 12, I-44100 Ferrara, Italy
b CNR-Centro di Studio su Fotoreattivita` e Catalisi, Dipartimento di Chimica dell’Universita` di Ferrara, Via L. Borsari 46, I-44100 Ferrara, Italy
Received 2 April 2002; accepted 12 August 2002
Abstract
The synthesis of a series of indenyl amido titanium dimethyl complexes, by means of the direct synthesis from the ligand, a 2-fold
excess of MeLi, and TiCl4 is reported. The 1H NMR spectra of the complexes show a quartet structure for the metal-bound methyl
groups, due to through-metal protonꢁproton coupling. Coupling of Ti-methyl protons with protons on the Cp ring is also revealed
/
by COSY 2D-NMR. The performance of the Ti complexes in propylene polymerization, including [Me2Si(Me4C5)(t-BuN)]TiMe2
(1-TiMe2), [Me2Si(Ind)(t-BuN)]TiMe2 (2-TiMe2) and six other methyl titanium complexes bearing substituted indenyl ligands, has
been investigated with different cocatalysts and at different polymerization temperatures and propylene concentrations. All
complexes produce amorphous polypropylene (am-PP). The catalytic activity and molecular weight strongly depend on the
substitution of the Cp ring: 2-TiMe2 gives polymers of lower molecular weight, while the presence of a methyl group in position 2 (as
in 3-TiMe2) determines up to 4-fold increase in molecular weight. The type of cocatalyst influences mainly the catalytic activity, the
borates being better activators than MAO, but also molecular weight, with again the borates giving higher molecular weights than
MAO. 5-TiMe2ꢁ
first order in monomer. The following activation energies for overall chain release have been calculated: DDE% 2-TiMe2ꢃ
molꢂ1, DDE% 5-TiMe2ꢃ3.8 kcal molꢂ1, DDE% 3-TiMe2ꢃ6.3 kcal molꢂ1. Even if all the polymers produced are amorphous, 2-
/
Ph3CB(C6F5)4 shows an overall activation energy of polymerization of 7.35 kcal molꢂ1. The rate of chain release is
3.4 kcal
/
/
/
TiMe2 and 5-TiMe2 show a microstructure unbalanced towards isotacticity, while 3-TiMe2, 6-TiMe2 and 8-TiMe2 are syndiotactic-
enriched. Chiral induction comes mainly from a weak enantiomorphic site control.
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: Indenyl amido titanium dimethyl complexes; Amorphous polypropylene
1. Introduction
and miscibility of this polyolefin with, for example,
isotactic [2,4,5] or syndiotactic polypropylenes [3,4,6].
One of the reference catalysts for the production of
high molecular weight am-PP is the so-called ‘con-
strained geometry’ titanium complex [Me2Si(Me4C5)(t-
As part of our continuing interest in amorphous
polypropylenes (am-PP) [1ꢁ6], we are investigating
/
known and new Group 4 metal complexes with the
aim of finding catalysts able to produce am-PP with
varying degrees of microstructures and molecular
weights, properties that determine the processability
BuN)]TiCl2 (1-TiCl2) that is used with either AlR3ꢁ
B(C6F5)3 or methylalumoxane (MAO) as cocatalysts
[7ꢁ13].
/
/
Both 1-TiCl2 and [Me2Si(Me4C5)(t-BuN)]ZrCl2 (1-
ZrCl2) have been extensively investigated, and the
results show that Ti is clearly superior to Zr within
ꢀ Corresponding author
E-mail address: luigi.resconi@basell.com (L. Resconi).
this family of complexes [7ꢁ13]. Ligand variations, on
/
1
Present address: FIS Fabbrica Italiana Sintetici, v.le Milano 26, I-
36075 Montecchio Maggiore, Vicenza, Italy.
the Cp as well as on the type of bridge and the amide
substituent, have been pursued. Previous studies by
Canich [14] and Waymouth [15] have shown that the
2
Present address: Glaxo Wellcome Medicines Research Center, via
Fleming 4, I-37135 Verona, Italy.
0022-328X/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 2 - 3 2 8 X ( 0 2 ) 0 1 8 5 3 - 3

6
L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ26
/
Cp substitution pattern has limited influence on the
stereoregularity of polypropylene, while both regioregu-
larity and molecular weights are affected to a greater
extent. The nature of the bridge affects the catalytic
activity in propylene polymerization and, to a minor
degree, the polymer microstructure [16]. The steric bulk
of the amido substituent generally affects the polymer
molecular weight, in a manner, which depends on Cp
substitution and monomer type [14,15,17].
The influence of the cocatalyst was also addressed in
different studies, although in this case the differences are
less clear-cut [18,19].
In order to screen the influence of the p ligands on PP
microstructure and molecular weight, we needed a
simple and reliable method for the synthesis of different
complexes. We have recently reported the successful
preparation of a series of dimethylmetallocenes, by
means of a one-pot synthesis from the ligand, a 2-fold
followed by oxidation, because TiCl4 leads to metal
reduction [12]. In our case, TiCl4 could be used without
problems, since extensive reduction was not observed.
This result shows that also Ti complexes of commercial
relevance can be produced conveniently with our
procedure.
We then turned our attention to the related (Ind)Si-
Me2(t-BuNH) ligand, which has been investigated by
Stevens et al. [7], Herrmann [9], Okuda [11] and Way-
mouth [15] in the synthesis of asymmetric ‘constrained
geometry’ catalysts. Following the procedure described
by Stevens et al. [7], we have first obtained (1-inde-
nyl)dimethylchlorosilane in 89% yield, free from its
vinylic isomer but contaminated by 4% bisindenyldi-
methylsilane; then the final indenyldimethyl(t-BuNH)si-
lane ligand was obtained in 83% yield, in a 75:25 ratio of
its allylic and vinylic isomers (Scheme 1).
Okuda reported that conversion of the ligand to the
[Me2Si(Ind)(t-BuN)]TiCl2 complex occurs in 94% yield
following the reaction sequence of Scheme 1, while the
excess of MeLi, and MtCl4 (Mtꢃ
/
Ti, Zr, Hf) [20ꢁ23].
/
The same protocol was successfully applied to the
synthesis of the dimethylsilylcyclopentadienyl amido
complexes of both Zr and Ti, such as [Me2-
following methylation with MeMgCl at ꢂ78 8C gave
/
[Me2Si(Ind)(t-BuN)]TiMe2 as a yellow oil in 49% yield
[11]. Stevens et al. [7] and Waymouth et al. [15] on the
Si(Me4C5)(t-BuN)]TiMe2
Si(Me4C5)(t-BuN)]ZrMe2 (1-ZrMe2) [21].
(1-TiMe2)
and
[Me2-
other side reported yields of 20ꢁ25% using salt methat-
/
We describe here the application of this simplified
protocol to the synthesis of a series of indenyl amido
titanium complexes, which differ in the substituents on
indene. We also describe the results of propylene
polymerization, in both liquid monomer and solution,
with different cocatalysts and under different polymer-
ization conditions.
esis between the TiCl4(THF)2 adduct and the dilithio
salt of the ligand. [Me2Si(Ind)(t-BuN)]ZrCl2 has been
analogously prepared by Stevens et al. [7], by reaction of
ZrCl4(THF)2 with the dilithio salt of indenyldimethyl(t-
butylamido)silane in 36% yield, while [Me2Si(Ind)(t-
BuN)]ZrMe2 has not been reported so far. The related
[Me2Si(Ind)(t-BuN)]Ti(NMe2)2 and [Me2Si(Ind)(t-
BuN)]Zr(NEt2)2 have been prepared by Herrmann in
quantitative yield from the corresponding tetrakis(dialk-
ylamido)metals [9].
2. Results and discussion
In our hands with the one-pot method, the novel
[Me2Si(Ind)(t-BuN)]ZrMe2 (2-ZrMe2) was obtained as
a brown solid in 90% yield after extraction, while
[Me2Si(Ind)(t-BuN)]TiMe2 (2-TiMe2) could be isolated
in 70% yield as a dark yellow powder. Analogously, six
other Ti dimethyl complexes have been prepared in
yields from 61 to 87%. The complexes prepared and
reaction yields are listed in Table 1. All samples were
purified by a single filtration, yielding dark colored
pentane or toluene solutions from which the complexes
were isolated by removing the solvents under reduced
pressure. Due to the very high solubility of these
dimethyl complexes, 1-TiMe2-8-TiMe2 have been tested
as precatalysts in the polymerization of propylene
without further purification.
2.1. Synthesis of the complexes
1-TiCl2 has been previously obtained in overall 32%
yield from the dilithium salt of the ligand [24], or in 52%
yield from the ligand dimagnesium salt [8,15]. Alterna-
tively, 1-TiCl2 can be prepared in quantitative yield by
reaction of the ligand dimagnesium salt (obtained in
79% yield) with Ti(O-i-Pr)4, followed by reaction with
SiCl4 in an overall yield of about 77% from the ligand
[8]. 1-TiMe2 was also obtained from [Me2Si(Me4C5)(t-
BuN)]Ti(O-i-Pr)2, by reaction of the latter with excess
AlMe3 (100% yield) [8]. The synthesis of 1-ZrCl2
proceeds in better yield (85% from ZrCl4(THF)2 and
the dilithium salt of the ligand) [10] while the dimethyl
derivative 1-ZrMe2 has not been reported so far.
With our method, at room temperature, we obtained
1-ZrMe2 in high yield (89%, entry 2 in Table 1). The
analogous, catalytically more important 1-TiMe2 was
obtained in 70% yield, which is notably higher than the
yields obtained in the conventional three-step procedure
[24]. The latter method requires the use of TiCl3(THF)3
The indenyl complexes studied in this work are shown
in Chart 1.
2.2. NMR characterization
1H and 13C chemical shifts of protons and carbons on
the indenyl fragment as well as on Si and Mt are listed in

L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ
/26
7
Table 1
All reactions were carried out at room temperature
a
Label
Complex
Purity (%wt., 1H-NMR)
Yield (%)
1-TiMe2
1-ZrMe2
2-TiMe2
2-ZrMe2
3-TiMe2
4-TiMe2
5-TiMe2
6-TiMe2
7-TiMe2
8-TiMe2
[Me2Si(Me4C5)(t-BuN)]TiMe2
[Me2Si(Me4C5)(t-BuN)]ZrMe2
[Me2Si(Ind)(t-BuN)]TiMe2
ꢀ95
ꢀ98
ꢀ97
ꢀ98
ꢀ98
85
70
89
70
90
70
66
61
79
86
87
[Me2Si(Ind)(t-BuN)]ZrMe2
[Me2Si(2-MeInd)(t-BuN)]TiMe2
[Me2Si(3-t-BuInd)(t-BuN)]TiMe2
[Me2Si(4,7-Me2Ind)(t-BuN)]TiMe2
[Me2Si(3-PhInd)(t-BuN)]TiMe2
[Me2Si(2-Me-4-PhInd)(t-BuN)]TiMe2
[Me2Si(2-Me-Benz[e]Ind)(t-BuN)]TiMe2
96
90
85
ꢀ96
a
% Weight isolated yield, not corrected by purity.
A coupling between protons H3 and H7 in 2-MtMe2
(MtꢃTi, Zr), 3-TiMe2, 7-TiMe2, 8-TiMe2 is usually
/
observed owing to a long range coupling (J5) typical of
indenyl systems [25].
The 13C-NMR spectra are assigned from DEPT-135,
1
1Hꢁ13
/
C HSQC and Hꢁ13
/
C HMBC 2D experiments.
Protonated carbons are assigned from their cross peaks
with directly bonded protons in the 1Hꢁ13
C HSQC
spectrum [26,27]; for quaternary carbons 1Hꢁ13
HMBC 2D spectra [28] are used.
/
/
C
1
Scheme 1.
In the Hꢁ13
C HMBC spectra the quaternary carbon
/
of the t-Bu is identified from the cross-peaks with its
methyl protons, the carbon C1 is identified from its
cross-peaks with Si-methyl protons and with the proton
or the methyl protons in position 2.
Table 2a and b, respectively. The assignments follow the
numbering scheme shown in Chart 2, for 2-MtMe2
(Mtꢃ
/
Ti, Zr)-7-TiMe2, and in Chart 3 for 8-TiMe2.
Ti, Zr)-8-TiMe2 show
The spectra of 2-MtMe2 (Mtꢃ
/
For more detailed NMR data see the Section 5.
some common features. The assignments of the 1H-
NMR spectra are based on the bidimensional COSYgs
[29] and NOESY [30] spectra. The proton spectra of 2-
MtMe2 are compared in Fig. 1. In the proton spectra,
the two methyls on 29Si are identified from the peak
multiplicity as they present at the base a doublet due to
2.3. Propylene polymerization
In order to evaluate to what extent different sub-
stituents on the indenyl ring can influence catalyst
performance, we tested complexes 2-TiMe2-8-TiMe2 in
propylene polymerization under a variety of conditions.
Selected polymerization results from 1-TiCl2 and 1-
their coupling with 29Si (Iꢃ
4.7%).
/
1/2, natural abundanceꢃ
/
A peculiarity of the 1H-NMR spectrum of the
titanium complexes is the quartet structure (a broad
singlet if resolution is not good enough) showed by the
metal-bound methyl groups. The COSY experiments
TiMe2
ison.
ꢁMAO catalysts are also reported for compar-
/
Polymerizations in both liquid monomer and in
solution were performed to compare catalytic activity,
polymer microstructure and molecular weight. Different
cocatalysts, namely methylalumoxane (MAO), triphe-
nylcarbenium tetrakis(pentafluorophenyl)borate ([Ph3-
C][B(C6F5)4]), N,N-dimethylanilinium tetrakis(penta-
show a protonꢁproton coupling between the two methyl
/
groups on the metal, accounting for the multiplicity of
the signal. A coupling with titanium can be reasonably
excluded since the observed quartet is clearly due to the
coupling with a nucleus of nearly 100% abundance,
while Ti has a low isotopic abundance (47Tiꢃ
/7.4%,
fluorophenyl)borate
([PhNHMe2][B(C6F5)4])
and
49Tiꢃ
/5.4%).
tris(pentafluorophenyl)borane (B(C6F5)3), were tested
to study the effect of different counterions on catalyst
behavior. For some of the catalysts we carried out a
deeper investigation by changing polymerization tem-
perature and monomer concentration.
Moreover, coupling of Ti-methyl protons with pro-
tons on the Cp ring is also present. The presence of
through-metal homo- and heteronuclear long-range
couplings was already observed in the case of meso-
[C2H4(4,7-Me2-1-Ind)2]ZrMe2 [20].

8
L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ
/26
Chart 1. The complexes of the present study.
2.3.1. Propylene polymerization in liquid monomer with
MAO cocatalyst
The polymerization results from MAO-activated Ti
clopentadienyl ligand affords the highest molecular
weights.
The most representative propylene polymers have
been analyzed by 13C-NMR. The triad content, racemic
dyad excess (% rde [32,33]) and triad tests (E and B
[32,33]) for the determination of the stereocontrol
mechanism are reported in Table 3. The methyl pentad
region of the spectrum of sample 3 is shown in Fig. 2.
The methyl region of spectra of am-PP produced by two
complexes 1-TiX2 (XꢃCl, Me), 2-TiMe2, 3-TiMe2, 7-
/
TiMe2 and 8-TiMe2 are compared in Table 3. 4-TiMe2
and 6-TiMe2 showed no or very low activity (test not
reported in Table 3) and were not further investigated.
As expected, 1-TiCl2 and 1-TiMe2 behave identically in
terms of catalyst activity and molecular weight and
tacticity of the polymer. All other catalysts produce am-
PP with molecular weights that are strongly influenced
by the substitution of the Cp ring and polymerization
temperature, and only marginally by the MAO/Ti ratio.
Catalysts activities are on the low side, when compared
with MAO-activated metallocenes [1]. As observed by
Waymouth [15], the unsubstituted indenyl ligand in 2-
TiMe2 induces relatively low molecular weights, even
under liquid monomer conditions (see runs 9 and 10 in
Table 3). As shown by Spaleck and coworkers for C2-
symmetric ansa-zirconocenes [31], substituting 2-MeInd
for Ind as in 3-TiMe2, 7-TiMe2 and 8-TiMe2 generates
up to 4-fold increase in molecular weight (compare runs
metallocene-based catalysts, meso-C2H4(H4Ind)2ZrCl2ꢁ
MAO [1], and rac-CH2(3-iPr-Ind)2ZrCl2ꢁMAO [2], are
also shown for comparison in the Fig. 2.
/
/
It is apparent that am-PP produced with 1-TiCl2 (and
1-TiMe2), although amorphous, have a syndiotactic-
enriched microstructure, in accordance with the finding
of Waymouth [15]. Longer syndiotactic sequences
(rrrrrr) can be observed, although the triad distribution
does not enable us to tell what mechanism is operating
with this catalysts. On the other side, the very low level
of mmmm sequences is not consistent with the existence
of tight ion pairs during monomer insertion. 1-TiCl2
shows a negligible effect of polymerization temperature
on syndiotacticity, while a strong effect on molecular
weight can be noted.
9ꢁ
/
10 with 11ꢁ13 in Table 3). For PP from 8-TiMe2 the
/
molecular weight is lower than expected, although
higher than that made with 2-TiMe2. In turn, 8-TiMe2
shows the highest catalytic activity. The tetramethylcy-
Both 2-TMe2, sporting the unsubstituted indenyl
ligand, and 7-TMe2 produce nearly atactic PP: the

Table 2
Chemical shift (ppm)
Complex C2-CH3 H2
¯
H3
H4
H5
H6
H7
H8 SiÃCH3 in
H9 SiÃCH3 out
H10 MtÃCH3 in
H11 MtÃCH3 out
¯
¯
¯
¯
(a) 1 H
2-TiMe2
2-ZrMe2
3-TiMe2
4-TiMe2
5-TiMe2
6-TiMe2
7-TiMe2
8-TiMe2
ꢁ
ꢁ/
/
6.05
6.31
7.01
6.68
6.76
7.48
7.39
7.44
7.81
7.07
7.03
7.07
7.11
6.83
6.88
6.92
7.46
7.58
7.51
7.53
0.53
0.40,0.60
0.56
0.36
ꢂ0.15
ꢂ0.74
ꢂ0.11
ꢂ0.12
ꢂ0.19
0.0065
0.005
0.82
0.24
0.85
0.99
0.78
0.68
0.85
0.83
1.99
ꢁ/
6.89
6.84
0.46
0.38
0.39
0.42
0.47
0.49
ꢁ/
ꢁ/
ꢁ/
1.95
2.06
6.15
6.19
6.39
ꢁ/
7.09
0.63
0.57
ꢁ/
7.96
6.71
ꢁ/
ꢁ/
7.20
7.30
7.08ꢁ
7.11ꢁ
ꢁ/
/
7.18 6.92
7.32 6.97
7.21
7.53
7.52
7.44
0.61
0.60
ꢁ/
ꢁ/
ꢁ/
ꢁ/
/
0.60
ꢂ0.33
Complex C1
(b) 13 C
C2-CH3 C2
¯
C3
C4
C5
C6
C7
C8 SiÃCH3 in
C9 SiÃCH3 out
C10 MtÃCH3 in
C11 MtÃCH3 out
¯
¯
¯
¯
2-TiMe2
3-TiMe2
4-TiMe2
5-TiMe2
6-TiMe2
7-TiMe2
8-TiMe2
91.86
ꢁ
/
126.84 114.12 125.94
140.97 115.64 124.90
120.98 141.03 126.08
128.35 112.32 132.49
124.54 129.62 124.62
141.90 115.73 139.17
139.85 114.86 131.21
126.07
125.17
125.48 127.63
124.72 127.81
124.54 127.80
126.71 135.51
125.44 128.00
125.75 126.26
126.84 124.83
3.96
5.55
4.60
5.71
4.09
6.00
6.01
1.84
5.30
1.81
3.48
1.82
5.58
5.71
57.18
56.57
57.89
56.52
56.33
57.62
56.71
53.85
50.82
54.46
52.03
59.10
51.88
50.80
89.61
90.05
92.58
92.95
89.99
92.62
17.98
ꢁ/
ꢁ/
ꢁ/
18.51
18.42
125.25
125.71
126.65
125.35
129.22 or 132.35

10
L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ26
/
propylene concentration catalyst activities and molecu-
lar weights decrease, while the microstructure remains
unchanged.
Given the low activity observed at low pressure for
the MAO-activated complexes, the eight Ti complexes
were also tested in toluene with [Ph3C][B(C6F5)4] as
cocatalyst and Al(iBu)3 as scavenger. The results are
reported in Table 4. Again, 4-TiMe2 proved almost
inactive, followed by 6-TiMe2. In addition, the latter
also produces the lowest molecular weights of all
catalysts investigated. Hence, we focused our attention
on 2-TiMe2, 3-TiMe2 and 5-TiMe2. The tests performed
with these three complexes activated by [PhNHMe2]-
[B(C6F5)4] are also reported in Table 4. Polymerization
experiments were also carried out with B(C6F5)3 as the
activator, but under our chosen conditions it resulted
completely inactive (tests not reported in Table 4). Some
authors have already reported the noticeable activity
Chart 2. MtꢃTi, Zr.
/
Chart 3. 8-TiMe2. The peak numbering does not follow the correct
IUPAC numbering, to allow for an easier comparison with the
structures of the other complexes.
increase from B(C6F5)3 to [Ph3C][B(C6F5)4] [18,34ꢁ37],
/
which they attributed to the higher coordination ability
of [MeB(C6F5)3]ꢂ compared with [B(C6F5)4]ꢂ. In
combination with ‘constrained geometry’ catalysts this
interaction could be so strong to prevent the displace-
ment of the anion by the olefin, giving essentially
inactive species.
triads mm and rr are very similar to each other, and the
% rde, although higher than zero, are the lowest, to
indicate a marginal tendency toward syndiotacticity. In
all other cases, the tendency toward syndiotacticity
becomes more marked, following the order 1-TiMe2ꢁ
/
1-TiCl2ꢀ8-TiMe2ꢀ3-TiMe2ꢀ2-TiMe2ꢀ7-TiMe2.
/
/
/
/
While 1-TiCl2 is the most active catalyst, among the
indenyl-derivatives, 2-TiMe2 is the most active catalyst
when combined with [Ph3C][B(C6F5)4]. A good activity
is showed by 3-TiMe2 and 5-TiMe2, closely followed by
7-TiMe2. 8-TiMe2 is less active, at difference with what
observed in liquid monomer with MAO. With these
sterically open systems, no simple correlation between
ligand structure and activity could be derived.
With the exception of 3-TiMe2 and 8-TiMe2, all
catalysts produce relatively high levels of 2,1-insertions,
higher than observed in the corresponding ansa-zirco-
nocenes [1].
2.3.2. Propylene polymerization in solution: influence of
cocatalyst
MAO-activated 3-TiMe2, 5-TiMe2 and 6-TiMe2 were
also tested at 50 8C in toluene under 3 bar-g of
propylene pressure. For 3-TiMe2, as expected at lower
In the presence of the borate salt [PhNHMe2]-
[B(C6F5)4] all the three complexes tested showed almost
Fig. 1. Aromatic and methyl regions in 1H-NMR spectra of [Me2Si(Ind)(t-BuN)]ZrMe2 (2-ZrMe2, a) and [Me2Si(Ind)(t-BuN)]TiMe2 (2-TiMe2, b).
Peak assignments according to Chart 2. ꢀ, C6D5H, 7.15 ppm.

Table 3
Propylene polymerization: MAO activated catalysts
a
b
c
Run Catalyst
Type
Cocatalyst Al/Zr (mol molꢂ1
)
Temperature (8C) Time (min) Yield (g) Activity (kgpp (mmolTiꢄh)ꢂ1
)
% Triads
Rde (%)
E
B
2,1 (%)
/Mw/
mmol
mm mr rr
1
2
1-TiCl2 2.7
1-TiCl2 5.4
MAO
MAO
MAO
MAO
MAO
MAO
MAO
MAO
MAO
MAO
MAO
MAO
MAO
3000
1000
1000
1000
500
50
50
60
70
70
60
60
70
60
70
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
30
35.0
26.6
59.0
63.1
51.4
26.8
58.6
27.9
24.9
14.0
18.3
58.0
80.0
12.9
4.9
9.6 38.1 52.3 42.6
0.5 1.4 1.3
1 190 800
848 200
650 300
420 100
446 900
697 900
710 500
424 600
135 400
103 700
550 800
625 700
194 000
3
1-TiCl2 5.4
1-TiCl2 5.4
1-TiCl2 5.4
1-TiMe2 3.0
1-TiMe2 6.1
1-TiMe2 6.1
2-TiMe2 6.2
2-TiMe2 6.2
3-TiMe2 3.0
7-TiMe2 4.9
8-TiMe2 5.2
10.9
11.6
9.5
10.5 39.3 50.2 39.7
10.7 41.3 48.0 37.3
0.5 1.4 1.3
0.5 1.2 1.6
4
5
6
1000
500
8.8
9.6
10.5 38.9 50.6 40.0
0.5 1.4 1.6
7
8
500
4.6
4.1
9
1000
500
24.8 38.9 36.3 11.5
26.5 37.7 35.8 9.3
15.6 33.1 51.3 35.7
29.4 35.5 35.1 5.7
13.8 38.9 47.3 33.6
1.3 2.4 1.5
1.4 2.7
10
11
12
13
2.3
6.2
1000
1000
1000
0.9 2.9 0.6
1.7 3.3 1.1
0.7 1.7 0.7
11.9
30.8
Polymerization conditions: 1-L autoclave, propyleneꢃ300 g, 1 mmol Al(iBu)3.
a
Rde: racemic dyad excess; % rdeꢃ100([r]ꢂ[m])ꢃ% rrꢂ%mm. Positive numbers indicate syndiospecificity, negative ones isospecificity [32,33].
E, enantiomorphic site triad test. Eꢃ2[mm]/[mr] for a syndiotactic polymer; Eꢃ2[rr]/[mr] for an isotactic polymer. Eꢃ1 for perfect site control [32,33].
B, Bernoullian triad test. Bꢃ4[mm][mr]/[mr]2. Bꢃ1 for perfect Bernoullian distribution with chain-end control [32,33].
b
c

12
L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ26
/
in position 4 and that to syndiotacticity due to the
substituent in position 2 are perfectly balanced in 7-
TiMe2, which has substituents in both positions 2 and 4:
the am-PP is then almost completely atactic (%mmꢃ
/
28.9 :%rrꢃ31.0). The methyl region of the spectra of
/
/
three am-PPs with different microstructures is shown in
Fig. 3.
Quite high levels of 2,1-insertions are observed in
most samples, while they are practically absent in those
from 3-TiMe2 and 8-TiMe2: these two complexes gave
the lowest, albeit not nil, amounts of regiomistakes also
in liquid monomer. Interestingly, the borate activators
induce a higher concentration of regioerrors compared
with MAO.
The molecular weight strongly depends on the sub-
stitution of the Cp ring: the complex without any
substituent gives polymers of lower molecular weight,
while the presence of a methyl group in position 2
determines, as in the case of liquid monomer polymer-
ization, a nearly 3-fold increase in molecular weight. The
cocatalyst seems to have some influence on molecular
weight, with MAO-activated systems producing am-PP
of lower molecular weights. This effect is most evident in
the case of 3-TiMe2. If we assume chain transfer to
AlMe3 (from MAO) to be the origin of the lower
polymer molecular weight, formation of a less reactive
TiÃ
/
AlMe3 complex could also explain the lower activity
Fig. 2. Methyl pentad region of 13C-NMR spectra (C2D2Cl4, 120 8C)
of am-PP with various degrees of microstructure prepared from 1-
of MAO-cocatalyzed versus borate-cocatalyzed systems.
TiCl2 ꢁ
/
MAO, meso-[C2H4(H4Ind)2]ZrCl2 ꢁ
/
MAO and rac-[CH2(3-i-Pr-
Ind)2]ZrCl2 ꢁ/MAO in liquid monomer at 60 8C.
2.3.3. Propylene polymerization in solution: influence of
monomer concentration
the same activity, a little higher than those obtained with
MAO, but much lower than in the case of
[Ph3C][B(C6F5)4].
The influence of propylene concentration in the liquid
phase was investigated in toluene at 50 8C on 2-TiMe2,
3-TiMe2 and 5-TiMe2, activated by [Ph3C][B(C6F5)4], in
By comparing Table 3 with Table 4, it appears that
there is no strong influence on tacticity of propylene
concentration (compare runs 11 in Table 3 with 23 in
Table 4 for 3-TiMe2), nor of cocatalyst type: 2-TiMe2, 3-
TiMe2 and 5-TiMe2 show the same or very similar
degree of stereocontrol when activated by MAO,
[Ph3C][B(C6F5)4], or [PhNHMe2][B(C6F5)4].
Even if all the polymers produced are essentially
atactic, a microstructure unbalanced towards isotacti-
city is observed for some of them (isotactoid, amor-
phous polypropylene, iam-PP), while some others are
syndiotactic-enriched (syndiotactoid, amorphous poly-
propylene, sam-PP). In particular, precatalysts without
any substituent on the Cp ring as 2-TiMe2 [15] and 5-
the propylene pressure range of 2ꢁ
to propylene concentration of 0.9ꢁ
/
6 bar, corresponding
3.7 mol lꢂ1. The
/
different concentrations were obtained by varying the
propylene pressure at constant temperature. The results
are collected in Table 5. The catalytic activity clearly
increases with propylene concentration in the liquid
phase, but the trends are not always linear. 2-TiMe2
shows a nicely linear dependence of activity on [propyl-
ene], while 3-TiMe2 displays a clear higher order
dependence. Models have been developed to explain
such a non-linear dependence [33], although in the
present case the available experimental evidence does
not allow us to elect one model over the others. In
addition, since catalytic activity is influenced by many
variables including possibly different catalyst decay
rates, a deviation from a linear dependence on monomer
concentration is quite easy.
TiMe2 give rise to iam-PP (%mm ꢀ%rr), and it also
/
seems that a substituent in position 4 (5-TiMe2) could
enhance the tendency to isotacticity, as already observed
in propylene polymerization in liquid monomer. In the
presence of a substituent on the Cp ring (3-TiMe2, 6-
The microstructure, in terms of triad distribution and
amount of 2,1 inserted units, and the molecular weight
do not seem to change noticeably with monomer
concentration.
TiMe2 and 8-TiMe2) a sam-PP is produced (%mm B
/
%rr). The tendency to isotacticity due to the substituent

Table 4
Propylene polymerization in solution with different activators
a
b
b
b
Run Catalyst
Type
Cocatalyst
Time (min)
Yield (g)
Activity (kgpp (mmolTiꢄh)ꢂ1
)
% Triads
mm mr
Rde (%)
21.6
E
B
2,1 (%)
/
Mw/
mmol
rr
c
14
15
16
17
18
19
20
21
22
23
24
25
26
27
1-TiCl2
1
[Ph3C][B(C6F5)4]
[Ph3C][B(C6F5)4]
[Ph3C][B(C6F5)4]
[Ph3C][B(C6F5)4]
[Ph3C][B(C6F5)4]
[Ph3C][B(C6F5)4]
[Ph3C][B(C6F5)4]
[Ph3C][B(C6F5)4]
MAO
8
5
5.2
3.2
1.9
0.4
2.2
0.8
1.6
1.0
1.0
1.7
1.7
2.2
2.8
2.9
39.1
19.1
11.3
0.2
13.1 52.2 34.7
0.5 0.7
1.1 2.1
0.9 1.4
2.0
2.4
0.7
2-TiMe2
3-TiMe2
4-TiMe2
5-TiMe2
6-TiMe2
7-TiMe2
8-TiMe2
3-TiMe2
5-TiMe2
6-TiMe2
2-TiMe2
3-TiMe2
5-TiMe2
2
38.8 39.7 21.5 ꢂ17.3
20.5 45.3 34.2 13.7
109 900
398 200
1
10
25
10
15
10
10
60
45
60
10
14
15
4
1
13.0
1.6
42.6 37.6 19.8 ꢂ22.8
1.1 2.4
0.4 0.8
1.4 2.2
0.7 1.1
4.8
6.4
2.2
0.5
111 400
58 000
2
9.9 46.8 43.3
28.9 40.1 31.0
15.5 46.2 38.3
16.7 39.9 43.4
33.4
2.1
1
9.4
6.1
317 800
326 000
293 400
73 000
1
22.9
26.7
3
0.3
0.8
0.8 1.8 traces
3
MAO
MAO
40.4 39.0 20.6 ꢂ19.8
11.0 48.1 40.9 29.9
36.3 38.8 24.9 ꢂ11.4
20.2 44.3 35.5 15.3
41.1 37.8 21.1 ꢂ20.1
1.1 2.2
0.5 0.8
1.3 2.4
0.9 1.5
1.1 2.4
2.5
8
0.1
2.6
3.9
1.7
1.2
3.8
35 800
82 900
5
[PhNHMe2][B(C6F5)4]
[PhNHMe2][B(C6F5)4]
[PhNHMe2][B(C6F5)4]
5
3.75
2.4
3.1
508 600
105 200
a
Polymerization conditions: 260 ml Buchi glass autoclave, 100 ml toluene, 0.5 mmol Al(iBu) as scavenger in toluene, B/Tiꢃ1 (mol molꢂ1), Al/Tiꢃ1000 (mol molꢂ1), pressureꢃ3 bar-g,
¨
3
temperatureꢃ50 8C, precontact in toluene (5 ml): 30 s (time necessary to transfer the catalytic solution into the reactor).
See footnotes of Table 3.
b
c
In order to use this dichloride derivative in combination with a borate, 1-TiCl2 was previously alkylated with Al(iBu)3 (Al/Tiꢃ50 (mol molꢂ1), agingꢃ10 min).

14
L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ26
/
used for the study of the effect of monomer concentra-
tion. The tests were performed under the same monomer
concentration (1.85 mol lꢂ1), by modulation of the
propylene pressure determined by Aspen Plus calcula-
tion.
The results are collected in Table 6. The catalytic
activity seems to increase with the polymerization
temperature, but some trends are not completely linear
for the reasons described above. For 5-TiMe2 a linear
dependence of the catalytic activity from the tempera-
ture is observed in the range 20ꢁ
/
80 8C, and the
Arrhenius plot ln(Activity)ꢃ
/
ln Aꢂ
/
DE%/RT gives an
overall activation energy DE% 5-TiMe2 for the polymer-
ization process of 7.35 kcal molꢂ1. This value is very
similar, even if slightly lower, to those obtained with
metallocene catalysts (in the range of 10ꢁ
/
15 kcal molꢂ1
[39]).
The isotacticity degree shows a slight decrease and the
regioinversion content shows a slight increase as the
¯
polymerization temperature increases, while the Mw
¯
strongly decreases. The Arrhenius plots of ln Pn (esti-
/
¯
mated from Mw; see Section 3) versus 1/Tp for the three
catalysts are reported in Fig. 4. From the slope of the
line the DDE% (activation energy barrier for chain
release) can be calculated for the three catalysts:
DDE% 2-TiMe2 ꢃ3:4 kcal molꢂ1
DDE% 5-TiMe2 ꢃ3:8 kcal molꢂ1
DDE% 3-TiMe2 ꢃ6:3 kcal molꢂ1
;
;
:
Fig. 3. Methyl pentad region of the 13C-NMR spectra (C2D2Cl4,
120 8C) of am-PP with various degrees of microstructure prepared
from ‘constrained geometry’ catalytic precursors in solution at 50 8C.
ꢀ, Toluene.
The molecular weight of a polyolefin (here defined by
¯
the average degree of polymerization, Pn; estimated
¯
from Mw; see Section 3) made with single center
2.3.5. Mechanism of enantioface selectivity
catalysts (which operate by coordination polyinsertion
mechanism) is given by the ratio between the overall rate
of propagation (Rp) and the sum of all rates of chain
The exact determination of pentad distribution of
these samples is difficult, due to the presence of
considerable amount of erythro (E) and threo (T) 2,1
units. In isotactic polypropylene, the chemical shift of
the methyl of a propylene unit close to the 2,1E unit
overlaps with the mmrr signal. On the other hand, no
assignments are available for the same methyl in a non
isotactic environment and for the methyl of a propylene
near to a 2,1T unit. It is not yet possible to introduce
corrections in the experimental integrals to take into
account the presence of signals due to propylene units
near to regioerrors.
release reactions (Rr) [32,33,38].
P
Rp
¯
P ꢃ
P
n
Rr
Assuming for simplicity a first order reaction rate
with respect to monomer concentration, that is: Rpꢃkp
/
[M], when the average degree of polymerization is
independent from monomer concentration, as in the
present case, then the rate of chain release is first order
The experimental pentad distribution for the three
samples is reported in Table 7. As these samples have a
slight tendency towards isotacticity, to understand what
mechanism of enantioface selectivity is operating, the B
(for chain end control) and E (for enantiomorphic site
control) triad tests were applied, using triads calculated
from the experimental pentads. As the E test is close to 1
in monomer: Rrꢃkr [M]. Whether this is due to direct
/
b-H transfer to the coordinated monomer or to asso-
ciative displacement following a unimolecular b-H
transfer [38] cannot be established with the data at hand.
2.3.4. Propylene polymerization in solution: effect of
polymerization temperature
for all three samples (see Tables 3ꢁ6), we can conclude
/
Tests at different polymerization temperatures were
carried out with the same three catalytic systems already
that chiral induction comes mainly form a weak
enantiomorphic site control.

Table 5
Propylene polymerization in solution at different monomer concentrations
a
b
c
c
c
Run Catalyst
Type
Pressure (bar-g)
[Propylene]l.p. (mol lꢂ1
)
Time (min) Yield (g) Activity (kgpp (mmolTiꢄh)ꢂ1
)
% Triads
mm mr
Rde
%
E
B
2,1 (%)
/
Mw/
mmol
rr
28
29
15
30
31
32
33
16
34
35
36
37
18
38
39
2-TiMe2 1.7
2-TiMe2 1.7
2-TiMe2
2-TiMe2 1.5
2-TiMe2
3-TiMe2 1.3
1
2
3
4
5
1
2
3
4
5
1
2
3
4
5
0.87
1.57
2.26
2.95
3.65
0.87
1.57
2.26
2.95
3.65
0.87
1.57
2.26
2.95
3.65
7
7
0.6
2.6
3.2
3.0
3.4
1.1
0.8
1.9
2.7
3.0
1.8
0.7
2.2
3.2
1.7
3.0
13.2
19.1
24.0
29.1
3.4
38.8 39.6 21.7 ꢂ17.1 1.1 2.1 2.7
38.8 39.7 21.5 ꢂ17.3 1.1 2.1 2.4
35.7 39.3 25.0 ꢂ10.8 1.3 2.3 1.6
105 200
108 300
109 900
127 300
122 500
279 400
420 100
398 200
365 900
342 600
105 200
114 500
111 400
106 800
109 900
2
5
5
1
7
15
10
10
9
20.7 45.1 34.2
20.5 45.3 34.2
20.0 44.8 35.2
13.5 0.9 1.4 0.5
13.7 0.9 1.4 0.5
15.2 0.9 1.4 0.5
3-TiMe2
3-TiMe2
3-TiMe2
3-TiMe2
1
1
1
1
5.0
11.3
18.2
36.5
8.5
5
5-TiMe2 1.25
10
10
10
10
10
40.5 38.0 21.5 ꢂ18.9 1.1 2.4 3.9
42.6 37.6 19.8 ꢂ22.8 1.1 2.4 4.8
40.7 38.0 21.3 ꢂ19.3 1.1 2.4 3.6
5-TiMe2
5-TiMe2
5-TiMe2
5-TiMe2
1
1
1
1
4.2
13.0
19.4
10.4
a
Polymerization conditions: 260 ml Buchi glass autoclave, 100 ml toluene, 0.5 mmol Al(iBu) as scavenger in toluene, [Ph C][B(C F ) ] as cocatalyst, B/Tiꢃ1 (mol molꢂ1), temperatureꢃ50 8C,
precontact in toluene (5 ml): 30 s (time necessary to transfer the catalytic solution into the reactor).
¨
3
3
6 5 4
b
Propylene concentration in liquid phase in mol lꢂ1, obtained by interpolation of values calculated from Redlichꢁ
See footnotes in Table 3.
/
KwongꢁSoave equations (see Section 3).
/
c

Table 6
Propylene polymerization in solution at different temperatures
a
b
b
b
Run Catalyst
Type
Pressure (bar-g)
Temperature (8C)
Time (min) Yield (g) Activity (kgpp (mmolTiꢄh)ꢂ1
)
% Triads
mm mr
Rde (%)
E
B
2,1 (%)
/Mw/
mmol
rr
40
41
42
43
44
45
46
47
48
49
50
51
2-TiMe2 1.7
2-TiMe2 2.0
0.85
1.9
21
8
10
7
0.7
2.7
2.3
1.2
1.5
2.0
3.8
3.6
0.2
0.5
1.6
1.8
3.1
8.0
37.8 38.5 23.7 ꢂ14
1.2 2.4
1.2 1.9
2.4
2.7
190 400
138 700
93 100
46.5
63
2-TiMe2 1.8
2-TiMe2 1.8
3-TiMe2 1.5
3-TiMe2 1.5
3-TiMe2 1.5
3-TiMe2 1.5
5-TiMe2 1.0
5-TiMe2 1.0
5-TiMe2 2.0
3.3
5.0
11.1
8.2
80
20
5
32.8 42.1 25.1 ꢂ7.7
74 400
0.85
1.9
10
8
6.2
19.9 44.6 35.5
19.1 48.6 34.1
15.6
15.0
0.9 1.4 traces
1 036 700
433 500
253 900
160 600
210 400
132 100
90 200
44
65
10.0
15.4
9.7
3.3
5.0
10
15
12
12
10
12
80
23
0.8 1.2
1.1 2.4
1.2
3.3
0.85
1.9
1.0
2.8
41.8 37.6 20.6 ꢂ21.1
42.5
62
3.3
4.8
7.0
5-TiMe2 1.25 5.0
79
37.0 40.1 22.9 ꢂ14.2
1.1 2.1
4.1
75 800
a
Polymerization conditions: 260 ml Buchi glass autoclave, 100 ml toluene, 0.5 mmol Al(iBu) as scavenger in toluene, [Ph C][B(C F ) ] as cocatalyst, B/Tiꢃ1 (mol molꢂ1), precontact in toluene
¨
3
3
6 5 4
(5 ml): 30 s (time necessary to transfer the catalytic solution into the reactor). Propylene concentration in liquid phase: 1.85 mol lꢂ1
b
.
See footnotes of Table 3.

L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ
/26
17
of the free trimethylaluminum and used as 1 M toluene
solution. Polymerization grade propylene was obtained
from the Basell Ferrara plant. All complexes were
isolated by filtration and drying from a toluene solution,
1
and characterized by H- and 13C-NMR spectroscopy.
Elemental analysis in several cases did not give satisfac-
tory results, due to the limited air stability of these
dimethyl complexes.
3.2. 1H- and 13C-NMR analysis
The proton and carbon spectra of ligands and
metallocenes were obtained using a Bruker DPX 200
spectrometer operating in the Fourier transform mode
at room temperature (r.t.) at 200.13 MHz (1H) and
50.323 MHz (13C). The samples were dissolved in CDCl3
or C6D6. The residual peak of CHCl3 or C6D5H in the
1H spectra (7.25 and 7.15 ppm, respectively) and the
central peak of the solvent in the 13C-NMR spectra
(77.00 ppm for CDCl3 and 128.00 ppm for C6D6) were
used as references. Proton NMR spectra were acquired
with a 158 pulse and 2 s of delay between pulses; 16 or 32
transients were stored for each spectrum. The carbon
spectra were acquired with a 458 pulse and 6 s of delay
between pulses; about 512 transients were stored for
each spectrum. CDCl3 (Aldrich, 99.8 atom% D) and
C6D6 (Aldrich, 99.6 atom% D) were dried over P4O10 or
%
¯
Fig. 4. Arrhenius plots of ln(
3.4 kcal/mol), 3-TiMe2 (j, DDEr%elease
(', DDE%release
3.8 kcal/mol).
/
Pn) vs. 1/Tp for 2-TiMe2 (m, DDErelease
ꢃ/
ꢃ/
6.3 kcal/mol), and 5-TiMe2
ꢃ/
This result is confirmed by the application of both the
Bernoullian (for enantiomorphic site control) and the
(symmetric) Markovian (for chain end control) models
to the experimental pentad distribution. The calculated
pentads are reported in Table 7 together with the
probability parameters b (the probability for the inser-
tion of the preferred enantioface in the Bernoullian
model) and P(r) (the probability for the formation of an
r diad in the Markovian model). In the Table 7 the
values of the least-squares fitting L.S. is also reported.
The L.S. of the Bernoullian fitting is always lower that
the L.S. of the Markovian one, confirming the results
obtained from the E-test.
CaH2, distilled, and stored over activated molecular
˚
5 A).
sieves (4ꢁ
/
Carbon and proton NMR spectra of polymers were
recorded on a Bruker DPX-400 spectrometer operating
at 100.61 MHz in the Fourier transform mode, at
120 8C. The samples were prepared by dissolving 40
In spite of the non perfect fitting between experi-
mental and calculated pentads (likely due to the
presence of 2,1 units), this fitting is good enough for
the selection of the model [40].
1
mg of polymer (for 13C) or 10 mg (for H) in 0.5 ml of
1,1,2,2-tetrachloroethane-d2 at 120 8C. The peaks of
the mmmm pentad (21.8 ppm) and of C2HDCl2 (5.95
1
ppm) were used as internal reference in 13C- and H-
NMR spectra, respectively. Each carbon NMR spec-
3. Experimental
3.1. General procedures
trum was acquired with a 908 pulse, 12 s of delay
1
between pulses and CPD (waltz 16) to remove Hꢁ13
/
C
All operations were performed under nitrogen by
using conventional Schlenk-line techniques. Solvents
were purified by degassing with N2 and passing over
activated (8 h, N2 purge, 300 8C) Al2O3, and stored
under nitrogen. MeLi (Fluka or Aldrich), n-BuLi
(Aldrich), HexylLi (Aldrich), Me2SiCl2 (Aldrich),
TiCl4 (Aldrich), t-BuNH2 (Aldrich), 2-methylindene
(Boulder Scientific), t-butylindene (Boulder Scientific),
4,7-dimethylindene (Boulder Scientific), (Me4C5H)Si-
Me2(t-BuNH) (Boulder Scientific), indene (Aldrich),
B(C6F5)3 (Boulder Scientific), [Ph3C][B(C6F5)4] and
[PhNHMe2][B(C6F5)4] (Austin) were used as received.
Al(i-Bu)3 (Witco) was used as 1 M toluene solution and
MAO (methylalumoxane, Witco) was purchased as a 10
wt% solution in toluene and then used as received (liquid
propylene tests) or dried under vacuum to remove most
coupling. About 3000 transients were stored in 32K data
points using a spectral window of 60 ppm. Each proton
spectrum was acquired with a 458 pulse, 5 s of delay
between pulses. About 1K of transients were stored in
32K data points using a spectral window of 16 ppm.
3.3. Molecular weight measurements
The intrinsic viscosity (I.V.) was measured in tetra-
hydronaphthalene (THN) at 135 8C. The weight aver-
age molecular weights of am-PP were obtained from
their intrinsic viscosity values and the Markꢁ
/
Houwinkꢁ
/
Sakurada parameters derived by Pearson and Fetters:
0.737
¯
[h]ꢃ
/
1.85ꢄ
/
10ꢂ4ꢄ
The average degree of polymerization, Pn; is esti-
/
(
/
Mw)/
[41].
¯
¯
¯
¯
mated from Mw by assuming Mw=Mn ꢃ2:
/

Table 7
Analysis of pentad distribution of samples 18, 24 and 28
a
b
c
d
e
Sample
18
mmmx
rmmr
mmrr
xmrx
rmrm
rrrr
rrrm
mrrm
B
E
b
P(r)
L.S.
Exp
Bern
MK
Exp
Bern
MK
Exp
Bern
MK
0.3910
0.4104
0.3890
0.3796
0.4011
0.3785
0.3567
0.3778
0.3579
0.0299
0.0343
0.0500
0.0318
0.053
0.2042
0.1646
0.1000
0.2096
0.1640
0.1020
0.2033
0.1619
0.1059
0.1197
0.1371
0.2472
0.1284
0.1412
0.2477
0.1412
0.1517
0.2484
0.0522
0.0685
0.1000
0.0400
0.0706
0.1020
0.0459
0.0759
0.1059
0.0303
0.0343
0.0130
0.0351
0.0353
0.0141
0.0353
0.0379
0.0166
0.0528
0.0685
0.0509
0.0541
0.0706
0.0536
0.0571
0.0759
0.0593
0.1199
0.0823
0.0500
0.1213
0.0820
0.0510
0.1136
0.0810
0.0530
2.415
2.426
2.182
1.079
1.114
1.055
0.7547
0.7493
0.7335
4.21Eꢂ03
3.58Eꢂ02
0.3374
0.3446
0.3590
28
24
5.47Eꢂ03
3.62Eꢂ02
0.0510
0.0470
0.0379
0.0530
4.67Eꢂ03
2.96Eꢂ02
a
Bꢃ4[mm][rr]/[mr]2. Chain end control is identified by Bꢃ1.
Eꢃ2[rr]/[mr]. Site control is identified by Eꢃ1.
b
c
b, Probability for the insertion of the preferred enantioface in the Bernoullian model.
P(r), Probability for the formation of an r diad in the Markovian model.
L.S.ꢃapenteds(xxxxexpꢂxxxxcalc)2.
d
e

L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ
/26
19
3.4. GCꢁ
/
MS analysis
pressurized; the pressure was kept constant by feeding
propylene. The polymerization was stopped by degasing
the reactor and by adding 2 ml of methanol. The
polymer was precipitated with 200 ml of acidified
methanol, filtered, washed with methanol and dried
overnight at 60 8C under reduced pressure.
GCꢁMS analyses were carried out on a HP 5890-serie
/
2 gas-chromatograph and a HP 5989B mass spectro-
meter.
3.5. Determination of monomer concentration
The composition of liquid phase of propyleneꢁ
toluene mixtures was calculated from the Redlichꢁ
KwongꢁSoave equations [42ꢁ44]. This set of thermo-
/
3.8. Synthesis of [Me2Si(Me4C5)(t-BuN)]TiMe2 (1-
TiMe2)
/
/
/
dynamic equations was selected among those available
in Aspen PlusTM (commercialized by Aspen Technology
Inc., Release 9) on the basis of a comparison with the
experimental results. The propylene concentration was
hence calculated.
About 21.5 ml of a 1.6 M solution of MeLi in Et2O
(34.4 mmol) were slowly added at 0 8C to a solution of
2.12 g of (Me4Cp)Me2Si(t-BuNH) in 45 ml of diethyl
ether. During the addition an increasing turbidity
develops with final formation of a white suspension.
The mixture was allowed to warm up to r.t. and stirred
for 1 h. TiCl4 (0.93 ml, 8.45 mmol) were diluted with 10
ml of pentane. This solution was added to the Li salt
suspension in diethyl ether at r.t. (slightly exothermic
reaction with gas evolution). The resulting black suspen-
sion was stirred at r.t. for 1 h, then brought to dryness
under reduced pressure. The black solid obtained (4.26
g) was extracted with 90 ml of toluene and the filtrate
evaporated to dryness under reduced pressure to give
3.6. Polymerization in liquid monomer
Batch polymerizations were carried out in a 1-L
jacketed stainless-steel autoclave, equipped with magne-
tically driven stirrer, a 35 ml stainless-steel vial, and
connected to a thermostat for temperature control. The
reactor was purified by washing with a hexane solution
of Al(iBu)3, and then dried by purging with propylene at
80 8C for 1 h. The catalystꢁ
prepared by dissolving the amount of complex in the
required amount of MAOꢁtoluene solution, and aged
/cocatalyst mixture was
1
1.95 g of a dark brown sticky solid (70% yield). H-
NMR shows the presence of chemically pure [Me2-
Si(Me4Cp)(t-BuN)]TiMe2.
/
10 min at r.t. before being injected into the autoclave.
Al(iBu)3 (1 mmol) and the amount of propylene
reported in Table 3 were charged, at r.t., in the
autoclave. It was then thermostated at 2 8C below the
polymerization temperature and the catalyst system,
prepared as reported above, was injected in the auto-
clave by means of nitrogen pressure through the
stainless-steel vial. The temperature was rapidly raised
to the polymerization temperature, and the polymeriza-
tion was carried out at constant temperature, for the
time reported in Table 3. After venting the unreacted
monomer and cooling the reactor to r.t., the polymer
was dried under reduced pressure, at 60 8C.
1H-NMR (C6D6, d, ppm): 0.43 (s, 6H, Si-CH3); 0.50
¯
(s, 6H, Ti-CH3); 1.56 (s, 9H, t-Bu); 1.85 (s, 6H, Cp-
¯
CH3); 1.96 (s, 6H, Cp-CH3).
¯
¯
3.9. Synthesis of [Me2Si(Me4Cp)(t-BuN)]ZrMe2 (1-
ZrMe2)
About 12.16 ml of a 1.6 M solution of MeLi in Et2O
(19.46 mmol) were added at r.t. to 1.16 g (4.63 mmol) of
(Me4Cp)Me2Si(t-BuNH) in 25 ml of Et2O over about 5
min. The mixture was stirred for 2 h. An increasing
turbidity develops with final formation of a white
suspension, and then a mixture of 1.08 g of ZrCl4
(4.63 mmol) in 25 ml pentane was quickly added. The
mixture was stirred overnight and a brown solution is
finally obtained. The reaction mixture is brought to
dryness under reduced pressure, and the brown solid
was extracted with 60 ml of toluene and then the filtrate
was evaporated to dryness under reduced pressure to
3.7. Polymerization in solution
Propylene polymerizations were carried out in a 260
ml Buchi glass autoclave equipped with magnetic stirrer,
¨
thermocouple and feeding line for the monomer, pur-
ified with nitrogen and kept in a thermostatic bath.
Toluene (95 ml) and Al(iBu)3 (0.5 mmol) were intro-
duced into the autoclave and warmed to the polymer-
ization temperature, then the autoclave was fluxed with
propylene. The catalytic system was separately prepared
in 5 ml of toluene by mixing the desired amounts of
metallocene and cocatalyst. After about 30 s of stirring
at r.t., the solution was introduced into the autoclave
under monomer flow. The reactor was closed and
1
give 1.52 g of a light brown solid (89% yield). H-NMR
shows the presence of spectroscopically pure [Me2-
Si(Me4Cp)(t-BuN)]ZrMe2. The same experiment was
repeated at ꢂ
1H-NMR (C6D6, d, ppm): ꢂ
0.46 (s, 6H, SiÃCH3); 1.40 (s, 9H, t-Bu); 1.92 (s, 6H,
CpÃCH3); 1.97 (s, 6H, CpÃ
/
78 8C, giving a yield of 86%.
/
0.01 (s, 6H, ZrÃ
/
CH3);
¯
/
¯
/
/
CH3).
¯
¯

20
L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ26
/
3.10. Synthesis of [Me2Si(Ind)(t-BuN)]TiMe2 (2-
TiMe2)
aromatic protons overlapped with those of the allylic
isomer, 7.77 (d, 1H, ArÃH).
/
¯
3.10.1. IndSiMe2Cl
About 37.5 ml of a 2.5 M solution of n-BuLi in
3.10.3. [Me2Si(Ind)(t-BuN)]TiMe2
About 11.3 ml of a 1.6 M solution of methyllitium in
diethyl ether (18.04 mmol) were slowly added at
hexane (93.7 mmol, n-BuLi:indeneꢃ
dropwise to a solution of indene (11 ml, 84.9 mmol) in
60 ml of Et2O, previously cooled to ꢂ78 8C. At the end
/1.1) were added
ꢂ78 8C to a solution of 1.08 g (4.40 mmol) of
/
/
(Ind)SiMe2(t-BuNH) in 23 ml of diethyl ether. During
the addition an increasing turbidity develops with final
formation of a yellow suspension. This mixture was
allowed to warm to r.t. and stirred for 2 h. TiCl4 (0.5 ml,
4.40 mmol) were diluted in 23 ml of pentane. This
solution was added very slowly and cautiously to the Li
salt suspension in diethyl ether at r.t. The resulting dark
suspension was stirred at r.t. overnight. The reaction
mixture was then brought to dryness under reduced
pressure. The dark solid was extracted with 60 ml of
toluene and then the filtrate was evaporated to dryness
of the addition, the yellow slurry was allowed to reach
r.t. and stirred for 4 h to give an orange solution. The
solvents were evaporated under reduced pressure to give
a yellow solid, which was taken up in 75 ml of hexane.
The milky suspension was stirred for a few minutes, and
the lithium salt of indene (white precipitate) was filtered
and washed with hexane (3ꢄ20 ml). The solid was
/
again slurried in hexane (40 ml) and added to a stirred
solution of Me2SiCl2 (15.6 ml, 136.8 mmol, Me2SiCl2/
IndLiꢃ
/
1.5) in 50 ml of hexane, previously cooled to
ꢂ
/
78 8C. At the end of the addition, the mixture was
under reduced pressure to give 0.99 g of a grayꢁblack
/
allowed to reach r.t. and stirred overnight. The suspen-
sion was then filtered, and the filtrate brought to dryness
in vacuo to yield a light yellow oil of (1-Ind)SiMe2Cl
free from its vinylic isomer (16.5 g, 89% yield). About
solid (70% yield). 1H-NMR confirms formation of
[Me2Si(Ind)(t-BuN)]TiMe2.
1H-NMR (C6D6, d, ppm, assignments following
Chart 2): ꢂ
0.36 (s, 3H, SiÃ
0.82 (q, Jꢃ0.48 Hz, 3H, TiÃ
Bu); 6.05 (d, Jꢃ3.21 Hz, 1H, CpÃ
8.50, 6.64, 1.04 Hz, 1H, ArÃ
/
0.15 (q, Jꢃ
/
0.48 Hz, 3H, TiÃ
/
CH3, H10),
¯
¯
5% of bis(1-indenyl)dimethylsilane (rac/mesoꢃ
also present.
1H-NMR (CDCl3, d, ppm): 0.21 (s, 3H, SiÃ
0.26 (s, 3H, SiÃCH3), 3.77 (bt, Jꢃ1.87 Hz, 1H, CpÃ
6.68 (dd, Jꢃ5.39, 1.87 Hz, 1H, CpÃ
5.39, 1.87, 0.62 Hz, 1H, CpÃ
/
1:1.2) is
/
CH3, H9), 0.53 (s, 3H, SiÃ
/
CH3, H8),
¯
¯
¯
¯
/
/
CH3, H11), 1.44 (s, 9H, t-
¯
¯
/
CH3),
/
/
H2); 6.88 (ddd, Jꢃ
/
¯
¯
/
/
/
H),
¯
/
H6); 7.01 (dd, Jꢃ
/3.21, 0.83
¯
¯
/
/
H), 7.03 (ddd, Jꢃ
7.36 (m, 2H, ArÃ
7.61 (m, 1H, ArÃ
/
Hz, 1H, CpÃ
/
H3); 7.07 (ddd, Jꢃ
/
8.50, 6.64, 1.04 Hz, 1H,
¯
¯
/
H), 7.19ꢁ
H), 7.57ꢁ
/
/
ArÃ
/
H5); 7.46 (dq, Jꢃ
/
8.50, 1.04 Hz, 1H, ArÃ
/
H7); 7.48
¯
¯
¯
H), 7.48ꢁ
/
7.52 (m, 1H, ArÃ
/
/
/
(dt, Jꢃ
/
8.50, 1.04 Hz, 1H, ArÃ
/
H4).
¯
¯
¯
H).
13C-NMR (C6D6, d, ppm, assignments following
¯
Chart 2): 1.84 (C9Ã
/
Si); 3.96 (C8Ã
/
Si); 34.31 (CH3Ã
/
t-
¯
¯
¯
/
3.10.2. (Ind)SiMe2(t-BuNH)
About 5.6 g of (Ind)SiMe2Cl (26.8 mmol) in 10 ml
Et2O were slowly added with stirring to a solution of 6.6
ml of t-BuNH2 (62.9 mmol, t-BuNH2:(Ind)SiMe2Clꢃ
2.3) in 50 ml Et2O and cooled to ꢂ78 8C. At the end of
Bu); 53.85 (C11Ã
/
Ti); 57.18 (C10Ã
/
Ti); 58.52 (CÃ
t-Bu);
¯
¯
¯
91.86 (C1), 114.12 (C3); 125.48 (C6); 125.94 (C4); 126.07
¯
¯
¯
¯
(C5); 126.84 (C2); 127.63 (C7); 133.22 (C3a or C7a);
¯
¯
¯
¯
¯
/
133.44 (C7a or C3a).
¯
¯
/
For additional NMR data see Section 5.
the addition, the mixture was allowed to reach r.t. and
was stirred 24 h to give a white milky suspension. The
solvents were evaporated under reduced pressure, and
the residue was extracted with 40 ml of pentane and
filtered to remove the white ammonium salt from the
soluble product. The filtrate was concentrated in vacuo
3.11. Synthesis of [Me2Si(Ind)(t-BuN)]ZrMe2 (2-
ZrMe2)
About 12.8 ml of a 1.6 M solution of methyllitium in
diethyl ether (20.54 mmol) were added slowly at
1
to give a light lemon yellow oil (5.46 g, 83% yield). H-
ꢂ78 8C to a solution of 1.2 g (4.89 mmol) of
/
NMR analysis shows the formation of (Ind)SiMe2(t-
BuNH) as a mixture of two isomers (allilic, 75%; vinilic,
25%).
(Ind)SiMe2(t-BuNH) in 25 ml of diethyl ether. During
the addition an increasing turbidity develops with final
formation of a yellow suspension. This mixture was
allowed to warm to r.t. and stirred for 2 h. ZrCl4 (1.14 g,
4.89 mmol) were slurried in 25 ml of pentane. This
suspension was added to the Li salt suspension in diethyl
ether at r.t. The resulting brown suspension was stirred
at r.t. overnight. The reaction mixture was then brought
to dryness under reduced pressure. The brown solid was
extracted with 60 ml of toluene and then the filtrate was
evaporated to dryness under reduced pressure to give
1H-NMR (CDCl3, d, ppm, for the indenyl fragment
assignment see Chart 2), allylic isomer: ꢂ
SiÃCH3), 0.03 (s, 3H, SiÃCH3), 0.72 (bs, 1H, NÃ
1.28 (s, 9H, t-Bu), 3.68 (bt, Jꢃ
6.76 (dd, Jꢃ5.39, 1.87 Hz, 1H, CpÃ
5.39, 1.87, 0.62 Hz, 1H, CpÃ
/
0.01 (s, 3H,
/
/
/
H),
¯
¯
¯
/
1.87 Hz, 1H, CpÃ
/
H1),
¯
/
/
H), 6.98 (ddd, Jꢃ
/
¯
/
H), 7.15ꢁ
/
7.40 (m, 2H, ArÃ
H); vinylic isomer: 0.44 (s, 6H,
/
¯
H), 7.5ꢁ
/
7.61 (m, 2H, ArÃ
/
¯
¯
/
Si(CH3)2), 0.9 (bs, 1H, NÃ
H), 1.22 (s, 9H, t-Bu), 3.47
¯
¯
1
(bm, 2H, CpÃ
/
H1), 6.87 (t, Jꢃ
/
1.87 Hz, 1H, CpÃ
/
H2), 3
¯
1.62 g of a beige solid (90% yield). H-NMR shows the
¯

L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ
/26
21
presence of spectroscopically pure [Me2Si(Ind)(t-
BuN)]ZrMe2.
CÃ
/
H); vinylic isomer: 0.46 (s, 6H, SiÃ
/
CH3); 1.1 (s, 9H,
¯
¯
t-Bu); 2.06 (s, 3H, CH3); 3.05 (s, 2H, CH2); both
¯
¯
1H-NMR (C6D6, d, ppm, assignments following
isomers: 0.37 and 0.65 (bs, 1H, NÃH); 6.98ꢁ7.82 (m,
8H, ArÃ
/
/
¯
Chart 2): ꢂ
ZrÃCH3, H11), 0.40 (s, 3H, SiÃ
CH3), 1.31 (s, 9H, t-Bu); 6.31 (d, Jꢃ
/
0.74 (s, 3H, ZrÃ
/
CH3, H10), 0.24 (s, 3H,
/
H).
¯
¯
¯
/
/
CH3), 0.60 (s, 3H, SiÃ
/
¯
¯
¯
/
3.21 Hz, 1H, CpÃ
/
3.12.3. [Me2Si(2-MeInd)(t-BuN)]TiMe2
¯
H2); 6.68 (dd, Jꢃ
/
3.21, 0.83 Hz, 1H, CpÃH3), 6.92
/
About 25 ml of MeLi 1.6 M in Et2O (40 mmol) were
added at 0 8C to a solution of 2.53 g of (2-Me-
Ind)SiMe2(t-BuNH) (9.75 mmol), the reaction mixture
was allowed to warm up to r.t. and stirred 1.5 h. TiCl4
(1.07 ml) in pentane (9.75 mmol) were added very slowly
to the dilithium salt (exothermic reaction with gas
evolution). After stirring for 2 h, the solvents were
removed under reduced pressure, and the crude residue
was taken up in 50 ml of toluene, stirred 30 min, and
filtered to give, after evaporation of the solvent, 2.68 g
of dark brown powder. The powder was slurried in
pentane, filtered, and the extract brought to dryness
under reduced pressure to give 2.31 g of ochra powder
(71% yield). Heat stability tests, in the solid state and in
solution of C6D6, respectively, for 1 and 2 h at 50 8C,
indicate that the complex is more stable in the solid
state.
¯
¯
(ddd, Jꢃ
Jꢃ8.29, 6.74, 1.14 Hz, 1H, ArÃ
1.14 Hz, 1H, ArÃ
/
8.29, 6.74, 1.14 Hz, 1H, ArÃ
/
H6), 7.03 (ddd,
¯
/
/
H5), 7.39 (dt Jꢃ
/
8.29,
¯
/
H4); 7.58 (dq, Jꢃ
/
8.29, 1.14 Hz, 1H,
¯
ArÃ
/
H7).
¯
For additional NMR data see Section 5.
3.12. Synthesis of [Me2Si(2-MeInd)(t-BuN)]TiMe2
(3-TiMe2)
3.12.1. (2-MeInd)SiMe2Cl
About 22.1 ml of n-BuLi 2.5 M in hexane (55.25
mmol) were added at ꢂ
2-MeInd (50.23 mmol) in 70 ml of Et2O. The resulting
orange solution was stirred at ꢂ20 8C for 15 min, then
/
20 8C to a solution of 6.54 g of
/
allowed to warm up to r.t., and stirred overnight. The
solvents were removed giving a light orange lithium salt,
which was suspended in hexane and filtered; the
insoluble in hexane was washed twice with hexane and
dried. The lithium salt was suspended in 70 ml of
1H-NMR (C6D6, d, ppm, assignments following
Chart 3): ꢂ
0.46 (bs, 3H, SiÃ
0.85 (q, Jꢃ0.48 Hz, 3H, TiÃ
Bu); 1.99 (s, 3H, C2ÃCH3); 6.76 (bs, 1H, H3); 6.89 (ddd,
Jꢃ8.41, 6.77, 1.08 Hz, 1H, H6); 7.07 (ddd, Jꢃ
6.77, 1.08 Hz,1H, H5); 7.44 (dt, Jꢃ
/
0.11 (q, Jꢃ
/
0.48 Hz, 3H,TiÃ
/
CH3, H10);
¯
¯
/
CH3, H9); 0.56 (bs, 3H, SiÃ
/CH3, H8);
¯
¯
¯
¯
hexane, cooled at ꢂ20 8C and added at this tempera-
/
/
/CH3, H11); 1.47 (s, 9H, t-
¯
¯
ture to a solution of 9.1 ml of Me2SiCl2 (75.02 mmol) in
60 ml of hexane. The resulting light orange mixture was
/
¯
¯
/
/8.41,
¯
stirred at ꢂ
r.t., and stirred overnight. The color of the final reaction
mixture was whiteꢁlight yellow. After filtration on G4
filter, the soluble in hexane was concentrated at 40 8C
under vacuum giving 8.40 g of a yellowꢁorange oil as
/
20 8C for 15 min, allowed to warm up to
/8.41, 1.08 Hz, 1H,
¯
H4); 7.51 (dq, Jꢃ
/
8.41, 1.08 Hz, 1H, H7).
¯
¯
13C-NMR (C6D6, d, ppm, assignments following
/
Chart 3): 5.30 (C9Ã
/
Si); 5.55 (C8Ã
/
Si); 17.98 (C2Ã
/
CH3);
¯
¯
¯
/
33.85 (CH3Ã
/
t-Bu); 50.82 (C11Ã
t-Bu); 89.61 (C1), 115.64 (C3); 124.72 (C6);
¯
/
Ti); 56.57 (C10Ã
/
Ti);
¯
¯
¯
product (75% yield). Purity by GC: 89.1% of target
product and about 6.4% of bis(2-Me-1-indenyl)di-
methylsilane.
1H-NMR (CDCl3, d, ppm, for the indenyl fragment
57.55 (CÃ
/
¯
¯
¯
124.90 (C4); 125.17 (C5); 127.81 (C7); 131.57 (C3a);
¯
¯
¯
¯
133.82 (C7a); 140.97 (C2).
For further NMR data see Section 5.
¯
¯
assignments see Chart 3): 0.22 (s, 3H, SiÃ
3H, SiÃCH3); 2.36 (bs, 3H, CH3); 3.64 (bs, 1H, H1);
6.70 (bs, 1H, H3); 7.18ꢁ
/
CH3); 0.47 (s,
¯
/
¯
¯
¯
3.13. Synthesis of [Me2Si(3-t-BuInd)(t-BuN)]TiMe2
(4-TiMe2)
/
7.56 (m, 4H, ArÃ
/
H).
¯
¯
3.12.2. (2-MeInd)SiMe2(t-BuNH)
About 5.02 g of (2-MeInd)SiMe2Cl (25.53 mmol) in
Et2O were added at 0 8C to a solution of 4.18 g of t-
BuNH2 (56.16 mmol) to give a yellow slurry. The
mixture was stirred at r.t. for 16 h. The solvents were
evaporated under reduced pressure, and the residue
extracted with 50 ml of toluene to give, after filtration
and evaporation of the solvent, 5.52 g of an orange oil
(83% yield). 1H-NMR analysis shows the presence of (2-
MeInd)SiMe2(t-BuNH) as a mixture of two isomers
(allylic, 60.2%, vinylic, 39.8%).
3.13.1. (3-t-BuInd)SiMe2Cl
About 24 ml di n-BuLi 2.5 M in hexane (60 mmol)
were added at 0 8C to a solution of 9.3 g (10 ml) of t-Bu
indene (54 mmol) in Et2O, obtaining a light yellow
suspension, and the mixture of reaction was stirred for 2
h at r.t. A 7.16 ml (7.66 g, 59.4 mmol) of Me2SiCl2 were
dropwise at 0 8C to lithium salt and the suspension was
stirred for 2 h at r.t. The solvent was dried in vacuo and
the residue was extracted with 50 ml of toluene,
obtaining 13.85 g of an orange oil (81% yield). 1H-
NMR spectrum confirms formation of (t-BuInd)Si-
Me2Cl, purity 83.8% wt and about 4.0% wt of bis(1-
indenyl)dimethylsilane was also present.
1H-NMR (C6D6, d, ppm), allylic isomer: ꢂ
(s, 3H, SiÃCH3); 0.11 (s, 3H, SiÃCH3); 1.02 (s, 9H, t-
Bu); 2.14 (s, 3H, CH3); 3.21 (s, 1H, CÃ
/
0.09
/
/
¯
¯
/
H); 6.52 (s, 1H,
¯
¯

22
L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ26
/
1H-NMR (C6D6, d, ppm): ꢂ
0.02 (s, 3H, SiÃCH3); 1.34 (s, 9H, t-Bu); 3.43 (d, Jꢃ
2.07 Hz, 1H, CÃ
/
0.05 (s, 3H, SiÃ
/
CH3);
3.14. Synthesis of [Me2Si(4,7-Me2Ind)(t-BuN)]TiMe2
(5-TiMe2)
¯
/
/
¯
/
H); 6.24 (d, Jꢃ
/
2.07, 1H, CÃ
/
H); 7.07ꢁ
/
¯
¯
3.14.1. (4,7-Me2Ind)SiMe2Cl
7.63 (m, 4H, ArÃ
/
H). m/z (%): 264 (35) [Mꢅ]; 208 (30);
¯
About 29.26 ml of n-BuLi (73.15 mmol) were drop-
wise at 0 8C to a solution of 9.59 g (10 ml) di 4,7-
dimethyl indene (66.5 mmol) in 25 ml di Et2O, obtaining
a light yellow suspension. The reaction mixture was
stirred at r.t. for 2 h, then the lithium salt was slowly
added at 0 8C to a solution of 9.54 g of Me2SiCl2 (8.97
93 (91); 57 (100).
3.13.2. (3-t-BuInd)SiMe2(t-BuNH)
About 13.85 g of (t-BuInd)SiMe2Cl (52.3 mmol) were
added at 0 8C to a solution of 8.98 g (12.9 ml) of t-
BuNH2 in Et2O, obtaining a yellow suspension. At the
end of addition the mixture of reaction was warm up to
r.t. and stirred overnight. The solvent was dried in vacuo
and the residue was extracted with 40 ml of toluene and
the filtrate was concentrated in vacuo to give an orange
ml, 73.15 mmol) in 20 ml of Et2O, obtaining a whiteꢁ
/
light yellow suspension. After a night at r.t., the solvent
was dried in vacuo, then the residue was exracted with
60 ml di toluene, the filtrate was brought to dryness
under reduced pressure, obtaining 15.25 g of an orange
oil.
1
1H-NMR (CDCl3, d, ppm): 0.32 (s, 3H, SiÃ
0.43 (s, 3H, SiÃCH3); 2.61 (s, 3H, CH3ÃAr); 2.62 (s, 3H,
CH3ÃAr); 4.05 (m, 1H, CÃ 6.92 (m, 1H, CÃH);
/
CH3);
oil (14.39 g, 91% yield). H-NMR spectrum shows the
presence only of allilic isomer.
¯
/
/
1H-NMR (C6D6, d, ppm, for the indenyl fragment
¯
¯
/
/
/
H); 6.82ꢁ
/
¯
¯
¯
assignment see Chart 2): ꢂ
(s, 3H, SiÃCH3); 0.38 (bs, 1H, NÃ
H); 1.00 (s, 9H, C3Ã
/
0.13 (s, 3H, SiÃ
/
CH3); ꢂ0.08
/
7.05ꢁ
/
7.29 (m, 3H, CpÃ
/
Hꢅ
/
ArÃ/H).
¯
¯
¯
/
/
H); 0.39 (bs, 1H, NÃ
/
¯
¯
/
t-Bu); 1.38 (s, 9H, NÃ
H); 6.31 (d, Jꢃ2.07, 1H, CÃ
/t-Bu); 3.33 (d,
3.14.2. (4,7-Me2Ind)SiMe2(t-BuNH)
¯
Jꢃ
/
2.07, 1H, CÃ
/
/
/
H); 7.07ꢁ
/
About 15.25 g of (4,7-Me2Ind)SiMe2Cl (64.39 mmol)
in 40 ml of Et2O, were added at 0 8C to a solution of
15.22 ml (10.59 g, 141.66 mmol) of t-BuNH2 in 30 ml of
Et2O, obtaining a yellow suspension. After a night at
r.t., the suspension was brought to dryness under
reduced pressure and the residue was extracted with 50
ml of toluene. The extract was dried in vacuo obtaining
¯
¯
7.68 (m, 4H, ArÃ
/
H).
¯
3.13.3. [Me2Si(3-t-BuInd)(t-BuN)]TiMe2
About 34.91 ml of MeLi (48.88 mmol) were dropwise
at 0 8C to a solution of 3.64 g (4 ml) of (t-BuInd)Si-
Me2(t-BuNH) (12.07mmol) in 25 ml of Et2O, obtaining
an orange solution, and the reaction mixture was stirred
at r.t. for 2 h. TiCl4 (1.33 ml, 12.07 mmol) were added at
r.t. to lithium salt, obtaining a dark suspension
(exothermic reaction with gas evolution). After 2 h the
solvent was dried in vacuo and the crude residue was
extracted with 50 ml of toluene, obtaining 4.4 g of a
black sticky solid which was extracted with 40 ml of
pentane, the solvent was removed under reduced
pressure obtaining 3.02 g of dark brown oil (66% yield).
1H-NMR (C6D6, d, ppm, assignments following
1
16.01 g of an orange oil. H-NMR confirms formation
of (4,7-Me2Ind)SiMe2(t-BuNH).
1H-NMR (CDCl3, d, ppm): ꢂ
/
0.043 (bs, 3H, SiÃ
/
CH3); 0.05 (bs, 3H, SiÃ
/
CH3); 0.64 (bs, 1H, NÃH);
/
¯
¯
¯
1.22 (s, 9H, t-Bu); 2.48 (s, 3H, CH3); 2.51 (s, 3H, CH3);
¯
¯
3.74 (t, Jꢃ
/
1.87, 1H, CÃ
/
H); 6.74 (dd, Jꢃ
/
5.45, 1.87 Hz,
¯
1H, CÃH); 6.91ꢁ
/
/
7.03 (m, 3H, ArÃ
/
Hꢅ
/
CÃH).
/
¯
¯
¯
3.14.3. [Me2Si(4,7-Me2Ind)(t-BuN)]TiMe2
About 44.41 ml of MeLi (62.17 mmol) were dropwise
at 0 8C to a solution of 4.2 g of (4,7-Me2Ind)SiMe2(t-
BuNH) (5 ml, 15.35 mmol) in 40 ml of Et2O, obtaining a
Chart 2): ꢂ
0.38 (s, 3H, SiÃ
0.99 (q, Jꢃ0.34 Hz, 3H, TiÃ
t-Bu); 1.49 (s, 9H, C3Ãt-Bu); 6.15 (s, 1H, H2); 6.84
(ddd, Jꢃ7.70, 6.67, 0.97 Hz, 1H, H6); 7.11 (ddd, Jꢃ
7.76, 6.67, 1.07 Hz, 1H, H5); 7.53 (dt, Jꢃ
/
0.12 (q, Jꢃ
/
0.34 Hz, 3H, TiÃ
/
CH3, H10);
yellowꢁorange solution, the reaction mixture was stirred
/
¯
¯
/
CH3, H9); 0.63 (s, 3H, SiÃ
/
CH3, H8);
at r.t. for 1 h. TiCl4 (1.69 ml, 2.91 g, 15.35 mmol) were
added at r.t. to lithium salt, obtaining a brown suspen-
sion (light exothermic reaction with gas evolution).
After 1 h the solvent was dried in vacuo and the residue
was extracted with 50 ml of toluene, obtaining 3.43 g of
a dark brown oil, which resulted to be the desired
¯
¯
¯
¯
/
/
CH3, H11); 1.45 (s, 9H,NÃ
/
¯
¯
/
¯
/
/
¯
/8.61, 1.05 Hz,
¯
1H, H7); 7.81 (dt, Jꢃ
/
7.70, 1.05 Hz, 1H, H4).
¯
¯
13C-NMR (C6D6, d, ppm, assignments following
1
product (61% yield). Purity by H-NMR: 95.71% wt.
Traces of starting ligand (2.75% wt) were also present.
Chart 2): 1.81 (CH3ÃSi, C9); 4.60 (CH3ÃSi, C8), 30.54
/
/
¯
¯
¯
¯
1H-NMR (C6D6, d, ppm, assignments following
(C3Ã
/
CH3Ã
/
t-Bu); 34.19 (C3Ã
/
CÃ
/
t-Bu); 34.29 (NÃ
/
CH3Ã
/
¯
¯
¯
t-Bu); 54.46 (C11 CÃ
/
Ti); 57.89 (C10Ã
/
C Ti); 58.77 (NÃ
/
Chart 2): ꢂ
0.39 (q, Jꢃ0.34 Hz, 3H, SiÃ
Hz, 3H, SiÃCH3, H8); 0.78 (q, Jꢃ
CH3, H11); 1.47 (s, 9H, t-Bu); 2.25 (s, 3H, CH3Ã
/
0.19 (q, Jꢃ
/
0.54 Hz, 3H, TiÃ
/
CH3, H10);
¯
¯
¯
¯
CÃ
/
t-Bu); 90.05 (C1); 120.98 (C2); 124.54 (C6); 125.25
¯
/
/
CH3, H9); 0.57 (q, Jꢃ
/
0.34
0.54 Hz, 3H, TiÃ
C7);
3.40 Hz, 1H, H2);
¯
¯
¯
¯
¯
/
(C5); 126.08 (C4); 127.80 (C7); 132.38 (C3a); 135.96
¯
/
/
¯
¯
¯
¯
¯
(C7a); 141.03 (C3).
/
¯
¯
¯
¯
¯
For additional NMR data see Section 5.
2.31 (s, 3H, CH3Ã
/
C4); 6.19 (d, Jꢃ
/
¯
¯

L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ
/26
23
6.71 (dq, Jꢃ
/
6.89, 0.93 Hz, 1H, H6); 6.83 (dq, Jꢃ
/
6.89,
3.15.3. (3-PhInd)SiMe2(t-BuNH)
¯
0.93 Hz, 1H, H5); 7.09 (d, Jꢃ
/
3.40 Hz, 1H, H3).
¯
About 9.71 g (34.09 mmol) of (3-PhInd)SiMe2Cl in 35
ml of Et2O, obtained as reported above, were added at
0 8C to a solution of 7.68 ml of t-BuNH2 in 25 ml of
Et2O and the orange suspension obtained was stirred
overnight at r.t. The solvent was evaporated under
reduced pressure and the crude (14.18 g) was extracted
with 50 ml of toluene, the filtrate was dried in vacuo
obtaining 10.41 g of a dark orange oil (67% yield).
¯
13C-NMR (C6D6, d, ppm, assignments following
Chart 2): 3.48 (CH3Ã
/
Si, C9); 5.71 (CH3Ã
/
Si, C8);19.1
¯
¯
¯
¯
(CH3Ã
/
C4); 22.8 (CH3Ã
/
C7); 34.36 (CH3Ã
/
t-Bu); 52.03
¯
¯
¯
(CH3Ã
/
Ti, C11); 56.52 (CH3Ã
/
Ti, C10); 58.59 (CÃt-Bu);
/
¯
¯
¯
¯
¯
92.58 (C1); 112.32 (C3); 125.71 (C5); 126.71 (C6), 128.35
¯
¯
¯
¯
(C2); 132.49 (C4); 132.55 (C7a); 134.73 (C3a); 135.51
¯
¯
¯
¯
(C7).
¯
1
For further NMR data see Section 5.
Purity by H-NMR: 70.32% wt.
1H-NMR (CDCl3, d, ppm): 0.07 (s, 3H, SiÃ
/
CH3);
¯
0.11 (s, 3H, SiÃ
Bu); 3.82 (d, Jꢃ
Hz, 1H, CÃH); 7.25ꢁ
/
CH3); 0.81 (bs, 1H, NÃ
/
H); 1.32 (s, 9H, t-
¯
¯
3.15. Synthesis of [Me2Si(3-PhInd)(t-BuN)]TiMe2 (6-
TiMe2)
/
2.15 Hz, 1H, CÃ
/
H); 6.84 (d, Jꢃ2.15
/
¯
/
/
7.83 (m, 9H, ArÃ
/
H).
¯
¯
3.15.4. [Me2Si(3-PhInd)(t-BuN)]TiMe2
3.15.1. 1-Phenylindene
About 35.25 ml (56.40 mmol) of MeLi 1.6 M in Et2O,
were added at 0 8C to a solution of 4.51 g (14.03 mmol)
of (3-Ph Ind)SiMe2(t-BuNH), obtained as reported
About 24.13 ml (72.40 mmol) of PhMgBr were added
dropwise to a solution of 6.45 g (48.27 mmol) of 1-
indanone in 35 ml of Et2O, previously cooled at
above, in 25 ml of Et2O, the solution redꢁorange
/
ꢂ
/
78 8C, obtaining a grey suspension. The mixture of
obtained was stirred 1h at r.t. To the lithium salt were
added 1.54 ml (14.03 mmol) of TiCl4 in 5ml of pentane
(exothermic reaction with gas evolution). The dark
brown suspension obtained was stirred 1 h at r.t. The
solvents were evaporated under reduced pressure, the
crude (9.45 g) was extracted with 50 ml of toluene, the
dark brown suspension obtained was filtrated and the
filtrate dried in vacuo obtaining 4.91 g of product target
reaction was allowed to warm up to r.t. in about 4 h and
1
subsequently stirred overnight. The H-NMR spectrum
showed the formation of the 1-Ph-indanol. Then the
solvent was evaporated under reduced pressure, the
residue was dissolved in 40 ml of toluene and were
added some crystals of p-toluenesolfonic acid. After 1.5
h the mixture of reaction was extracted with a solution
aqueous of NaHCO3 (2ꢄ
50 ml). The organic layer was dried over Na2SO4.
Filtration followed by removal of the solvent, resulted
1
/
50 ml), then with water (2ꢄ
/
as a dark brown sticky solid (79% yield). Purity by H-
NMR: 89.65% wt.
1H-NMR (C6D6, d, ppm, assignments following
in the isolation of 7.79 g of a yellowꢁ
/
orange oil and the
1H-NMR spectrum confirm the formation of product
target (71% yield).
Chart 2): 0.0065 (bs, 3H, TiÃ
SiÃCH3, H9); 0.61 (s, 3H, SiÃ
TiÃ
(ddd, Jꢃ
2H, H5ꢅHpara); 7.21ꢁ
/
CH3, H10); 0.42 (s, 3H,
¯
¯
/
/
CH3, H8); 0.68 (bs, 3H,
¯
¯
¯
¯
¯
/
CH3, H11); 1.45 (s, 9H, t-Bu); 6.39 (s, 1H, H2); 6.92
¯
¯
1H-NMR (CDCl3, d, ppm): 3.56 (d, Jꢃ
/2.15 Hz, 2H,
/
8.61, 6.65, 0.98 Hz, 1H, H6); 7.08ꢁ
/7.18 (m,
¯
CH2); 6.64 (t, Jꢃ
/
2.15 Hz, 1H, CÃ
/
H); 7.28ꢁ7.60 (m, 9H,
/
/
/
7.31 (m, 1H, Hmeta); 7.53 (dt,
¯
¯
¯
¯
¯
ArÃ
/
H).
¯
Jꢃ
7.96 (dt, Jꢃ
13C-NMR (C6D6, d, ppm, assignments following
/
8.61, 0.98 Hz, 1H, H7); 7.63ꢁ7.68 (m, 1H, Hortho);
/
¯
¯
/
8.61, 0.98 Hz, 1H, H4).
¯
3.15.2. (3-PhInd)SiMe2Cl
Chart 2): 1.82 (C9Ã
/
Si); 4.09 (C8Ã
/
Si); 34.42 (CH3Ã
/
t-
¯
¯
¯
About 13.8 ml (34.49 mmol) of n-BuLi were added
dropwise at 0 8C to a solution of 7.79 g (34.08 mmol) of
1-PhInd in 35 ml of Et2O, obtaining a red brown
solution, which was stirred 4 h at r.t. Then the litium
salt was siphoned at 0 8C in a solution of 4.22 ml (4.5 g,
34.49 mmol) of Me2SiCl2 in 20 ml of Et2O. The dark
yellow suspension obtained was stirred overnight at r.t.,
then the solvents were dried in vacuo and the crude
(12.27 g) was extracted with 50 ml of toluene, obtaining
Bu); 56.33 (C10Ã
/
Ti); 58.97 (CÃ
/
t-Bu); 59.10 (C11Ã
/
Ti);
¯
¯
¯
92.95 (C1); 124.54 (C2); 124.62 (C4); 125.44 (C6); 126.65
¯
¯
¯
¯
(C5); 128.00 (C7); 128.60 (Cpara); 128.64 (Cortho);
¯
¯
¯
¯
129.03 (Cmeta); 129.62 (C3); 131.46 (C3a); 134.56
¯
¯
¯
(C7a); 136.37 (CÃ
/
C3).
¯
¯
For additional NMR data see Section 5.
3.16. Synthesis of [Me2Si(2-Me-4-PhInd)(t-
BuN)]TiMe2 (7-TiMe2)
1
9.71 g of an orange oil (82% yield). H-NMR analysis
confirm the formation of (3-PhInd)SiMe2Cl. Purity by
1H-NMR: 81.89% wt.
3.16.1. (2-Me-4-PhInd)SiMe2Cl
About 6.54 ml (16.34 mmol) of nBuLi were added
dropwise at 0 8C to a yellow solution of 3.21 g (15.56
mmol) of 2-Me-4-PhIndene in 25 ml of Et2O, obtaining
immediately the formation of a yellow ochre suspension.
After 30 min of stirring at r.t., 1.96 ml (16.03 mmol) of
1H-NMR (CDCl3, d, ppm): 0.29 (s, 3H, SiÃ
/
CH3);
¯
0.34 (s, 3H, SiÃ
6.75 (d, Jꢃ2.15 Hz, 1H, CÃ
H).
/
CH3); 3.90 (d, Jꢃ
/
2.15 Hz, 1H, CÃ
/
H);
¯
¯
/
/
H); 7.26ꢁ
/
7.78 (m, 9H, ArÃ
/
¯
¯

24
L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ26
/
Me2SiCl2 dissolved in 6 ml of Et2O were added at 0 8C
to the lithium salt. The resulting light yellow suspension
was stirred 1 h at r.t. Then the solvents were dried in
vacuo and the crude, 5.21 g, was extracted with 40 ml of
toluene and the filtrate evaporated to dryness under
reduced pressure to give 4.15 g of an orange oil (77%
yield). Purity by 1H-NMR: 86.15% wt, 13.85% wt of (2-
Me-4-PhInd)2Me2Si.
(Cortho); 128.98 (Cmeta); 130.69 (C3a); 135.14 (C7a);
¯
¯
¯
¯
139.17 (C4); 141.08 (CÃ
/
C4); 141.90 (C2).
¯
¯
¯
For additional NMR data see Section 5.
3.17. Synthesis of [Me2Si(2-Me-Benz[e]Ind)(t-
BuN)]TiMe2 (8-TiMe2)
3.17.1. (2-Me-Benz[e]Ind)SiMe2Cl
1H-NMR (CDCl3, d, ppm): 0.21 (s, 3H, SiÃ
0.44 (s, 3H, SiÃCH3); 2.28 (bs, 3H, CH3); 3.67 (s, 1H,
CÃH); 6.82 (s, 1H, CÃ
/
CH3);
About 8.62 ml (21.56 mmol) of HexylLi were added
dropwise at 0 8C to a yellow solution of 3.7 g of 2-Me-
benz[e]indene (20.53 mmol) in 12 ml of Et2O and the
resulting light yellow suspension was stirred 30 min at
r.t. Then to the lithium salt cooled to 0 8C, were added
2.59 ml (2.76 g, 21.15 mmol) of Me2SiCl2 dissolved in 7
ml of Et2O. The mixture of reaction, a yellow suspen-
sion, was stirred 1h at r.t. The solvents were evaporated
under reduced pressure, and the crude 6.12 g, was
extracted with 50 ml of toluene. The filtrate was
evaporated to dryness under reduced pressure to give
4.26 g of (2-Me-3-H-cyclopenta[a]naphthalene)SiMe2Cl
as an orange oil (69% yield). Purity by 1H-NMR:
91.21% wt of target product and 8.79% wt of bis(2-
Me-3-H-ciclopenta[a]naphthalen)SiMe2.
¯
/
¯
¯
/
/
H); 7.16ꢁ
/
7.59 (m, 8H, ArÃ
/H).
¯
¯
¯
3.16.2. (2-Me-4-PhInd)SiMe2(t-BuNH)
About 3.27 ml (30.34 mmol) of t-BuNH2 dissolved in
10 ml of Et2O were added at ꢂ5 8C to a yellow solution
/
of 4.15 g (13.88 mmol) of (2-Me-4-PhInd)SiMe2Cl,
obtained as described above, in 25 ml of Et2O. The
resulting yellow suspension was allowed to reach r.t. and
stirred overnight. Then the solvents were evaporated
under reduced pressure and the crude, 6 g, was extracted
with 50 ml of toluene. The filtrate was concentrated in
1
vacuo to give 4.41 g of an orange oil. The H-NMR
analysis shows the formation of (2-Me-4-PhInd)Si-
Me2(t-BuNH) (97% yield) as a mixture of two isomers
(allylic, 90.29%; vinilic, 9.71%).
1H-NMR (CDCl3, d, ppm): 0.16 (s, 3H, SiÃ
0.40 (s, 3H, SiÃCH3); 2.42 (d, Jꢃ1.37 Hz, 3H, CH3);
3.82 (s, 1H, CÃH); 7.25ꢁ
/
CH3);
¯
/
/
¯
¯
¯
/
/
8.17 (m, 7H, ArÃ
/
Hꢅ
/
CpÃ
/
H).
1H-NMR (CDCl3, d, ppm): 0.00 (s, 3H, SiÃ
/
CH3);
¯
¯
¯
0.18 (s, 3H, SiÃ
Bu); 2.29 (d, Jꢃ
6.75 (m, 1H, CÃH) 7.12ꢁ
/
CH3); 0.64 (bs, 1H, NÃ
/
H); 1.22 (s, 9H, t-
¯
3.17.2. (2-Me-Benz[e]Ind)SiMe2(t-BuNH)
About 3.68 ml (34.34 mmol) of t-BuNH2 in 10 ml of
Et2O were added dropwise at 0 8C to a yellow solution
¯
/
1.37 Hz, 3H, CH3); 3.50 (s, 1H, CÃ
/
H);
¯
¯
/
/
7.62 (m, 8H, ArÃ
/
H).
¯
¯
of 4.26
g (15.61 mmol) of (2-Me-3-H-cyclopen-
3.16.3. [Me2Si(2-Me-4-PhInd)(t-BuN)]TiMe2
ta[a]naphthalene)SiMe2Cl, as obtained above, in 25 ml
of Et2O, obtaining a light yellow suspension which was
stirred overnight at r.t. The solvents were evaporated
under reduced pressure, and the crude 6.46 g, was
extracted with 40 ml of toluene. The filtrate was
evaporated to dryness under reduced pressure to give
4.57 g of an orange oil (95 5 yield). The 1H-NMR
spectrum shows the formation of (2-Me-Benz[e]Ind)Si-
Me2(t-BuNH) as a mixture of two isomers (allylic,
95.16%; vinilic, 4.84%).
About 34.02 ml (54.43 mmol) of MeLi 1.6 M in Et2O
were added at 0 8C to a yellow solution of 4.51 g (13.44
mmol) of (2-Me-4-PhInd)SiMe2(t-BuNH) in 15 ml of
Et2O, obtaining an orange suspension which was stirred
subsequently 30 min at r.t. Then to a lithium salt were
added at r.t. TiCl4 (1.49 ml, 2.58 g, 13.44 mmol)
dissolved in 10 ml of pentane (exothermic reaction
with gas evolution). This black suspension obtained
was stirred 1 h. The solvents were dried in vacuo and the
crude, 8.44 g, was extracted with 50 ml of toluene. The
filtrate was concentrated in vacuo to give 5.58 g of
product target as a black sticky solid (86% yield).
1H-NMR (CDCl3, d, ppm): ꢂ
0.14 (s, 3H, SiÃCH3); 0.66 (bs, 1H, NÃ
Bu); 2.41 (d, Jꢃ
7.17ꢁ8.17 (m, 7H, ArÃ
/
0.08 (s, 3H, SiÃ
/
CH3);
¯
/
/
H); 1.23 (s, 9H, t-
¯
¯
/
1.37 Hz, 3H, CH3); 3.66 (s, 1H, CÃ
/
H);
¯
¯
1H-NMR (C6D6, d, ppm, assignments following
/
/
Hꢅ
/
CpÃ
/
H).
¯
¯
Chart 2): 0.005 (bs, 3H, TiÃ
SiÃCH3, H9); 0.60 (s, 3H, SiÃ
TiÃ
6.97 (ddd, Jꢃ
7.11ꢁ
8.61, 0.98 Hz, 1H, H7); 7.62ꢁ
/
CH3, H10); 0.47 (s, 3H,
¯
¯
/
/
CH3, H8); 0.85 (bs, 3H,
¯
3.17.3. [Me2Si(2-Me-Benz[e]Ind)(t-BuN)]TiMe2
¯
¯
¯
¯
¯
/
CH3, H11);1.48 (s, 9H, t-Bu); 1.95 (s, 3H, C2Ã
/
CH3);
¯
About 37.36 ml of MeLi (59.78 mmol) were added at
0 8C to a yellow suspension of 4.57 g (14.76 mmol) of
(2-Me-Benz[e]Ind)SiMe2(t-BuNH) in 15 ml of Et2O,
/
8.61, 6.85 Hz, 1H, H6); 7.20 (s, 1H, H3),
¯
¯
/
7.32 (m, 4H, H5, Hpara, Hmeta); 7.52 (dt, Jꢃ
/
¯
¯
¯
/
7.69 (m, 1H, Hortho).
obtaining a redꢁorange solution which was stirred 1 h at
/
¯
¯
13C-NMR (C6D6, d, ppm, assignments following
r.t. Then to the lithium salt was added a solution of 1.63
ml (14.76 mmol) of TiCl4 in 8 ml of pentane, (exho-
termic reaction with gas evolution). After 1h the black
suspension was dried in vacuo and the crude, 9.22 g was
extracted with 40 ml of toluene. The filtrate was
Chart 2): 5.58 (SiÃ
/
C9); 6.00 (SiÃ
/
C8); 18.51 (C2Ã
/
CH3);
¯
¯
¯
34.38 (CH3Ã
/
t-Bu); 51.88 (TiÃ
/
C11); 57.62 (TiÃ
/
C10);
¯
¯
¯
58.08 (CÃ
/
t-Bu); 89.99 (C1); 115.73 (C3); 125.35 (C5);
¯
¯
¯
¯
¯
125.75 (C6); 126.26 (C7); 127.82 (Cpara); 128.62
¯
¯

L. Resconi et al. / Journal of Organometallic Chemistry 664 (2002) 5ꢁ
/26
25
evaporated to dryness under reduced pressure to give
5.14 g of target product as a green powder (87% yield).
merization temperature increases. The rate of chain
release is first order in monomer. No influence of
monomer concentration or polymerization temperature
on microstructure could be found, with the exception of
1
Purity evaluated by H-NMR: ]
/
96% wt.
1H-NMR (C6D6, d, ppm, assignments following
Chart 3): ꢂ0.33 (bs, 3H, TiÃCH3, H10); 0.49 (s, 3H,
SiÃCH3, H9); 0.60 (s, 3H, SiÃ
TiÃ
CH3); 7.21 (d, Jꢃ
/
/
2-Me2ꢁMAO. Chiral induction comes mainly from a
/
¯
¯
¯
¯
/
/
CH3, H8); 0.83 (bs, 3H,
weak enantiomorphic site control. The influence of
ligand structure on regioselectivity and copolymeriza-
tion performance deserves a deeper investigation. We
have pursued other ligand variations on this type of
complexes, and will report the results in a following
study.
¯
¯
¯
¯
/
CH3, H11); 1.46 (s, 9H, t-Bu); 2.06 (s, 3H, C2Ã
/
/
8.19 Hz, 1H, H6); 7.30 (s, 1H, H3);
¯
¯
¯
7.44 (d, Jꢃ
Hb); 7.57 (dm, Jꢃ
Hz, 1H, Ha).
¯
/
8.19 Hz, 1H, H7); 7.19ꢁ
/
7.46 (m, 2H, Hc,
¯
¯
/
7.83 Hz, 1H, Hd); 8.02 (dm, Jꢃ
/
8.02
¯
¯
13C-NMR (C6D6, d, ppm, assignments following
Chart 3): 5.71 (SiÃ
/
C9); 6.01 (SiÃ
/
C8); 18.42 (C2Ã
/
CH3);
¯
¯
¯
34.37 (CH3Ã
/
t-Bu); 50.80 (TiÃ
/
C11); 56.71 (TiÃ
/
C10);
¯
5. Supporting information
¯
¯
¯
57.41 (CÃ
/
t-Bu); 92.62 (C1); 114.86 (C3); 123.62 (Ca);
¯
¯
¯
¯
124.83 (C7); 126.42 (Cc); 126.84 (C6); 127.25 (Cb);
¯
Detailed NMR analysis and 2D-NMR spectra of the
complexes 2-ZrMe2 and 2-TiMe2-8-TiMe2.
¯
¯
129.05 (Cd); 129.22 (C3a or C5); 131.21 (C4); 132.35
¯
¯
¯
¯
(C5 or C3a); 132.55 (C7a); 139.85 (C2).
¯
¯
¯
¯
For further NMR data see Section 5.
Acknowledgements
4. Conclusions
We thank Anna Droghetti for the synthesis of
IndSiMe2NHt-Bu, Marcello Colonnesi for the 1H-
NMR spectra and Fabrizio Piemontesi for helpful
discussions on-NMR assignments.
We have described here a facile, highly efficient, one-
pot synthesis of ‘constrained geometry’ Group 4 metal
dimethyl complexes, by the reaction of the ligand with a
2-fold excess of MeLi, and MtCl4 (Mtꢃ
NMR and COSY 2D-NMR spectra of the complexes
confirm the presence of through-metal protonꢁproton
/
Ti, Zr). The 1H-
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