Zirconocene dichloride complexes with a 1,2-naphthylidene bridge as catalysts for the polymerisation of ethylene and propylene

Article abstract of DOI:10.1016/j.jorganchem.2004.03.021

Ansa-zirconocene dichloride complexes containing a 9-fluorenyl group at the 1-position of naphthalene and a 2-indenyl 12, 1-indenyl 13, or cyclopentadienyl 14 group at the 2-position of the naphthalene were synthesised and characterised. The molecular structures of the complexes have been determined by single crystal X-ray diffraction studies. After activation with excess methylalumoxane (MAO), the complexes were used as homogeneous catalysts for the homopolymerisation of ethylene and propylene.

Full text of DOI:10.1016/j.jorganchem.2004.03.021

Journal of Organometallic Chemistry 689 (2004) 1965–1977
www.elsevier.com/locate/jorganchem
Zirconocene dichloride complexes with a 1,2-naphthylidene bridge
as catalysts for the polymerisation of ethylene and propylene
a,
b,
b
b
Helmut G. Alt *, Robert W. Baker *, Mahmoud Dakkak , Michael A. Foulkes ,
a
Marc O. Schilling , Peter Turner
b
a
Lehrstuhl fur Anorganische Chemie II, Laboratorium f€ur Anorganische Chemie, Universit€at Bayreuth, Postfach 101251,
Universitaetsstrasse 30, NW I, D-95440 Bayreuth, Germany
b
School of Chemistry,University of Sydney, NSW 2006, Australia
Received 13 February 2004; accepted 17 March 2004
Abstract
Ansa-zirconocene dichloride complexes containing a 9-fluorenyl group at the 1-position of naphthalene and a 2-indenyl 12, 1-
indenyl 13, or cyclopentadienyl 14 group at the 2-position of the naphthalene were synthesised and characterised. The molecular
structures of the complexes have been determined by single crystal X-ray diffraction studies. After activation with excess methyl-
alumoxane (MAO), the complexes were used as homogeneous catalysts for the homopolymerisation of ethylene and propylene.
Ó 2004 Elsevier B.V. All rights reserved.
Keywords: Ansa-zirconocene; 1,2-Naphthylidene bridge; Catalysis; Olefin polymerisation
1. Introduction
like ‘‘self-immobilization’’ processes. The design of
such ‘‘multi-purpose’’ catalysts is a step into the di-
rection of nanotechnology. This contribution describes
the synthesis and catalytic properties of ansa-zircono-
cene complexes that possess a fluorenyl ligand that is
connected over a 1,2-naphthylidene bridge with a cy-
clopentadienyl or a 1-indenyl or 2-indenyl ligand. The
use of a 1,2-naphthylidene bridge stems from our in-
terest in the enantiospecific synthesis of planar chiral
fluorenylmetal complexes through the use of atrop-
isomerism [4,5]. To date there have been very few
examples of Group IV ansa-metallocenes having a
C(sp2)–C(sp2) bridge. Other examples reported include
the etheno-bridged complexes 1,2-dimethyl- and
[1,2-diphenyl-1,2-bis(cyclopentadienyl)ethene]TiCl2,
prepared by Burger and Brintzinger [6], and some
1,2-phenylidene-bridged complexes prepared by Hal-
terman et al. [7,8] ([1,2-bis(tetrahydro-1-indenyl)ben-
zene]Ti and ZrCl2, and [1,2-bis(1-indenyl)benzene]Ti
and ZrCl2). Arts et al. [9] have also reported the
preparation of [1,2-bis(2-indenyl)benzene]Zr and HfCl2
(together with some indenyl-substituted complexes),
and [1-(9-fluorenyl)-2-(2-indenyl)benzene]ZrCl2.
Zirconocene dichloride complexes activated with
methylalumoxane (MAO) are established as excellent
olefin polymerisation catalysts [1]. These catalysts can
be very versatile because small differences in the mo-
lecular structure of the metallocene unit can cause
considerable changes in the properties of the catalysts
and the polyolefins produced. In many cases, such
‘‘structure–property-relationships’’ allow the prediction
of catalyst and polyolefin features. In earlier studies
we have investigated the influence of various param-
eters such as the nature of the aromatic ligand [2], the
bridging unit [3] and ligand substituents [1(e)] in ansa-
metallocene complexes. As a result, tailored catalysts
could be prepared and applied for special purposes
* Corresponding authors. Tel.: +49-921-552-555; fax: +49-921-552-
044 (Helmut G. Alt), Tel.: +61-2-9351-4049; fax: +61-2-9351-6650
(Robert W. Baker).
E-mail addresses: helmut.alt@uni-bayreuth.de (H.G. Alt), r.bak-
er@chem.usyd.edu.au (R.W. Baker).
0022-328X/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.03.021

1966
H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
2. Results and discussion
Scheme 1. Coupling of 4 with fluorenyllithium provides
the 9-(1-naphthyl)fluorene 5 in 91% yield. A major ad-
vantage of the sulfoxide coupling methodology is that it
is rotamer-specific, with 5 obtained exclusively as the
rotamer where the ester moiety and the fluorene 9-H are
syn (designated sp) [4]. Following the precedence of
Bosnich and co-workers [11], reaction of 5 with the di-
Grignard reagent derived from 1,2-bis(chlorom-
ethyl)benzene provided the 2-indanol 6 in 75% yield.
Acid-catalysed dehydration of 6 provided the 2-indenyl
2.1. Synthesis of complexes 12, 13 and 14
The key starting material for the synthesis of all the
complexes, isopropyl rac-1-(phenylsulfinyl)naphthalene-
2-carboxylate (4), was prepared in an overall yield of
73% from 1-bromo-2-naphthalenecarboxylic acid (1)
(prepared from 2-methylnaphthalene according to the
procedure of Colletti and Halterman [10]), as outlined in
Scheme 1. (i) SOCl2 (10 equivalents), pyridine (1 equivalents), benzene, 25 °C, 16 h, then PriOH (2 equivalents), pyridine (2 equivalents), CH2Cl2, 25
°C, 30 min; (ii) PhSNa (1.2 equivalents), DMF, 70 °C, 16 h; (iii) OXONEÒ (2 equivalents), acetone (12 equivalents), MeCN/aqueous NaHCO3, 25
°C, 7 h; (iv) fluorenyllithium (1.2 equivalents), THF, 0 °C, 30 min; (v) 1,2-C6H4(CH2MgCl)2 (1.5 equivalents), THF, )78 to 25 °C, 16 h; (vi) 2-
(XMgCH2CH2)C6H4MgX (X ¼ Cl, Br; 3 equivalents), THF, )78 to 25 °C, 16 h; (vii) BrMgCH2CH ¼ CHCH2MgBr (2 equivalents), THF, )78 to 25
°C, 24 h; (viii) TsOH (0.05 equivalents), benzene, reflux, 20 min; (ix) SOCl2 (1.2 equivalents), Pri2NEt (2.9 equivalents), CH2Cl2, )78 °C to reflux, 20
h; (x) BuLi (2.4 equivalents), THF, 0 °C, 60 min, then ZrCl4 (1.1 equivalents), benzene, 25 °C, 90 min.

H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
1967
derivative 9 in 93% yield. Metallation of 9 was achieved
by di-lithiation with butyllithium in THF solution, fol-
lowed by replacement of the solvent with benzene and
reaction of the dilithio species with ZrCl4. After removal
of inorganic salts and concentration, the 2-indenyl ansa-
zirconocene complex 12 crystallised in 55% yield (the
synthesis and Xray crystal structure of complex 12 have
been previously reported in a short communication [5]).
The synthesis of the 1-indenyl complex 13 was
achieved using our recently reported di-Grignard strat-
egy for the synthesis of 3-substituted-1H-indenes [12].
Reaction of 5 with the di-Grignard reagent derived from
1-bromo-2-(2-chloroethyl)benzene provided the 1-inda-
nol 7 in 85% yield. Acid-catalysed dehydration of 7 then
provided the 3-indenyl derivative 10 in 72% yield. At
ambient temperature, slow rotation around the 2-nap-
thyl–3-indenyl bond leads to inequivalence of all the
fluorene carbon atoms in the 13C NMR spectrum of 10.
This slow rotation also produces substantial broadening
in the 1H NMR spectrum of 10 for the fluorene aromatic
protons and for the indene protons at the 1-position. On
cooling to 260 K these signals fully resolve and shar-
dehydration of 8 resulted in the formation of a large
amount of an unidentified side-product, however, de-
hydration could be carried out under basic conditions
(SOCl2 and excess Pri2NEt), affording the cyclopent-
1
adiene derivative 11 in 60% yield. The H NMR spec-
trum of 11 indicated the presence of both the
1,3-cyclopentadien-1-yl and 1,3-cyclopentadien-2-yl
tautomers in a ratio of 63:37 (or the reverse – the specific
identity of the major/minor isomers were not deter-
mined). When out of solution, compound 11 gradually
undergoes dimerisation, and so it was metallated im-
mediately upon isolation. Metallation was carried out
using the same method described above for the prepa-
ration of 12, with the complex 14 isolated in 51% yield.
2.2. X-ray crystallographic data
The solid state molecular structures of complexes 13
and 14 have been determined by X-ray diffraction anal-
ysis. ORTEP [16] depictions of the molecules are dis-
played in Figs. 2 and 3, together with the structure
previously determined for complex 12 [5] for comparison
(Fig. 1). Table 1 summarises the crystallographic data
and parameters for complexes 13 and 14, and Table 2
presents selected bond lengths and angles for all three
complexes. For all three complexes the fluorenyl ring
displays typical slippage towards the 9-position {crys-
tallographic number C(1)} [17], with the range of Zr–C
distances, D ¼ (Zr–Cmax) ) (Zr–Cmin) ¼ 0.307(7), 0.338(4)
1
pen. Metallation of 10 was carried out using the same
method described above for the preparation of 12, with
the complex 13 isolated in 55% yield.
For the preparation of the cyclopentadienyl complex
14, we sort to prepare the cyclopentadiene derivative 11
through a di-Grignard or diorganylmagnesium reaction
with the ester 5, analogous to our approach to the
syntheses of 9 and 10. The reaction of substituted but-
adienemagnesium complexes with carboxylate esters to
yield substituted 3-cyclopentenols has been previously
reported by Takase and co-workers [13], and Rieke et al.
[14]. Whilst butadienemagnesium can be prepared
through reaction of magnesium with butadiene in THF
solution in the presence of catalytic amounts of organ-
ohalides [15], we found it more convenient to generate
the complex by reacting 1,4-dibromo-2-butene with ex-
cess magnesium in THF solution at 0 °C, and then al-
lowing the butadiene generated in situ (together with
one equivalent of MgBr2) to react further with the
magnesium at room temperature over 18 h. Addition of
the resulting pale green suspension to the ester 5 ()78 °C
to room temperature over 24 h, then reflux 4 h) led to
formation of a complex mixture of products, with only
traces of the desired 3-cyclopentenol 8 present. It was
found, however, that addition of further MgBr2 (ca. 2
equivalents) to the butadienemagnesium complex sus-
pension resulted in its complete dissolution (presumably
through formation of the di-Grignard reagent), and that
addition of this solution to the ester 5 ()78 °C to room
temperature over 24 h) provided the desired 3-cyclo-
pentenol 8 in 31% yield. Attempted acid-catalysed
ꢀ
and 0.314(3) A [18], for 12, 13 and 14, respectively. For
complexes 12 and 13 the indenyl rings display typical
slippage towards the 2-position {crystallographic num-
ber C(25)} [19], with the range of Zr–C distances
ꢀ
D ¼ 0:163ð8Þ and 0.143(4) A for 12 and 13, respectively.
Fig. 1. ORTEP [16] depiction of complex 12 (reproduced from [5] by
permission of The Royal Society of Chemistry) with crystallographic
numbering; 20% displacement ellipsoids are shown for non-hydrogen
atoms.
1
Determination of the rotational barrier through DNMR methods
will be described elsewhere.

1968
H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
Table 1
Crystallographic data and parameters for complexes 13 and 14
Compound 13 14
Model formula C32H20Cl2Zrꢀ1.15C6D6 C28H18Cl2Zrꢀ1.5C6D6
Model molecular 663.37
weight
642.76
Crystal system
Space group
Monoclinic
Monoclinic
C2=c (no. 15)
20.864(6)
27.237(8)
11.129(3)
114.150(4)
5771(3)
P21=n (no. 14)
9.4450(10)
13.0020(10)
26.3900(10)
95.6460(10)
3225.1(4)
1.366
ꢀ
A (A)
ꢀ
B (A)
ꢀ
C (A)
b (°)
3
ꢀ
V (A )
Dc (g cmꢁ3
)
1.480
8
Z
4
Crystal size (mm) 0.442 ꢂ 0.226 ꢂ 0.138
0.459 ꢂ 0.191 ꢂ 0.176
Yellow
Prism
Crystal colour
Crystal habit
Temperature (K) 297(2)
Red
Prism
150(2)
0.71073
0.592
ꢀ
k(Mo Ka) (A)
l(Mo Ka)
0.71073
0.532
(mmꢁ1
)
Tmin;max
2hmax (°)
hkl range
0.907, 1.000a
56.14
0.786, 0.876b
56.54
Fig. 2. ORTEP [16] depiction of complex 13, with crystallographic
numbering; 20% displacement ellipsoids are shown for non-hydrogen
atoms.
)12 12, )17 17, )34 34 )27 27, )36 36, )14 14
33918
N
30511
Nind (Rmerge
)
7600 (0.019)
6618
353
6931 (0.025)
6275
361
N
Nvar
obsI > 2rðIÞ
Residualsc
0.0412, 0.1253
0.0212, 0.0603
R1ðF Þ; wR2ðF 2Þ
GoF(all)
1.065
1.005
)0.213, 0.396
Residuꢁa3l extrema )0.391, 1.017
ꢀ
(e A
)
a
SADABS multi-scan.
b Gaussian.
P
P
P
2
c R1 ¼ kFojꢁjFck= jFoj for Fo > 2rFoÞ; wR2 ¼ ð wðFo2 ꢁFc2Þ =
P
2
1=2
2
ðwFc2Þ Þ
all reflections, w ¼ 1=½r2ðFo2Þ þ ðXPÞ þ YPꢃ where
P ¼ ðFo2 þ 2Fc2Þ=3 and X and Y ¼ 0:0777 and 1.218 for 13, and 0.0384
and 2.8069 for 14.
tadienyl groups of 82.1° and 84.8°, respectively. In
addition, the cyclopentadienyl moieties display con-
symmetric rotations [20], with respect to the ZrCl2 bi-
sector, of 3.6° and )4.8° for the fluorenyl and
cyclopentadienyl groups, respectively (for the conformer
illustrated in Fig. 3), and there are deviations involving
the bonding angles associated with the a- and ipso-car-
bons of the cyclopentadienyl moieties and the naphtha-
lene bridge carbons. In solution relatively unrestricted
fluctuation between the enantiometric conformations
observed in the solid state structure of complex 14 can be
expected [20].
Fig. 3. ORTEP [16] depiction of complex 14, with crystallographic
numbering; 20% displacement ellipsoids are shown for non-hydrogen
atoms.
In complex 14 the cyclopentadienyl ring shows relatively
minor variation in the Zr–C distances, with D ¼ 0:056ð3Þ
ꢀ
A. There appears to be little strain associated with the
1,2-naphthylidene bridging unit, with the bonding angles
associated with the bridge [i.e., C(1)–C(14)–C(23) and
C(14)–C(23)–C(24)] narrowed only slightly by 2–3° for
all the complexes. While the solid state molecular struc-
ture for complex 12 shows only small deviations from
Cs-symmetry, complex 14 deviates significantly, with
dihedral angles between the mean plane of the naph-
thalene the mean planes of the fluorenyl and cyclopen-
2.3. Complexes 12, 13 and 14 as catalyst precursors for
homogeneous a-olefin polymerisation
2.3.1. Ethylene polymerisation
After the activation of compounds 12, 13 and 14 with
MAO (30 wt% in toluene), the catalysts 12/MAO, 13/
MAO and 14/MAO, in combination with triisobutylal-

H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
1969
Table 2
Selected distances (A) and angles (°) for complexes 12, 13 and 14
influence of the catalyst precursor structure on the po-
lymerisation activity was observed, with the indenyl
derivatives 12/MAO and 13/MAO possessing higher
activities than the catalyst containing the cyclopenta-
dienyl ligand 14/MAO. The reason for the increased
activity of the indenyl derivatives 12/MAO and 13/MAO
could be the so-called ring slippage reaction [17] of the
indenyl ligands in addition to the ring slippage of the
fluorenyl ligands. The ring slippage reaction, leading to
a change of the binding mode from g5 ! g3 ! g1, re-
sults in a decreased electron density and an increased
Lewis acidity of the central metal. Such an interpreta-
tion is reasonable when the olefin is considered as a
Lewis base and as long as all the other parameters that
have influence on the reaction kinetics remain constant.
The results of HT-GPC measurements show that the
highest molecular weights are observed for the poly-
ethylenes produced with the cyclopentadienyl derivative
14/MAO and the 1-indenyl derivative 13/MAO. The
molecular weights for the polyethylene produced with
the 2-indenyl derivative 12/MAO are significantly lower.
Assuming the principle chain transfer step is b-hydride
elimination, this may reflect a steric influence on the
growing polymer chain which favours to a greater de-
gree the conformation required for elimination. The
polydispersity of the polyethylenes grows with their
molecular masses. The highest polydispersity with
D ¼ 6:0 is found for the polymer produced with 14/
MAO. This behaviour presumably derives from slightly
different active sites generated during the polymerisa-
tion. This could be the consequence of the heterogeni-
sation process during the polymerisation, or the
formation of various ion pairs in the activation step with
MAO. The melting enthalpies and the crystallinities of
the polyethylenes are seen to decrease for increasing
molecular weight and polydispersity, while the melting
points increase. The polymers possess crystallinities be-
tween a ¼ 46 and 55%; these are typical values for
LDPE (low density polyethylene).
The dependence of the used MAO-aluminium to
zirconium ratio on the ethylene polymerisation activity
was investigated in the case of 12/MAO. MAO is a
dynamic mixture of various linear and cyclic MAO
oligomers [23]. The active MAO species consists of a
cage type compound containing monomeric trim-
ethylaluminium in the inside of the cage [24]. This sit-
uation explains the necessary high excess of MAO in
the activation process. As illustrated in Fig. 4, a higher
MAO-aluminium to zirconium ratio leads to an initial
marked increase in polymerisation activity of the cat-
alyst, which then plateaus. Similar behaviour has been
observed by Herfert and Fink [25] in the polymerisation
of ethylene using isopropylidene(cyclopentadienyl)(9-
fluorenyl)- ZrCl2/MAO; in this case activity plateaus at
an Al:Zr ratio of 5100:1 and then decreases at higher
ratios.
ꢀ
Compound
12a
13
14
ꢀ
Distances (A)
Zr(1)–Cl(1)
Zr(1)–Cl(2)
Zr(1)–Cfb
2.407(1)
2.412(1)
2.29(1)
2.4145(7)
2.4071(6)
2.30(1)
2.4260(6)
2.4273(6)
2.29(2)
Zr(1)–C(1)
Zr(1)–C(2)
Zr(1)–C(7)
Zr(1)–C(8)
Zr(1)–C(13)
Zr(1)–Cpc
2.406(3)
2.580(3)
2.704(4)
2.713(4)
2.552(3)
2.23(1)
2.405(2)
2.531(2)
2.711(2)
2.743(2)
2.604(2)
2.23(1)
2.4148(12)
2.5936(12)
2.7285(13)
2.6940(13)
2.5453(13)
2.19(1)
Zr(1)–C(24)
Zr(1)–C(25)
Zr(1)–C(26)
Zr(1)–C(b0)d
Zr(1)–C(a0)e
2.479(3)
2.467(4)
2.620(4)
2.630(4)
2.496(4)
2.483(2)
2.475(2)
2.528(3)
2.618(2)
2.565(2)
2.4930(13)
2.4753(13)
2.5166(15)
2.5313(13)
2.4982(13)
Angles (°)
Cl(1)–Zr(1)–Cl(2)
Cf–Zr(1)–Cp
99.03(5)
127.94(4)
117.7(3)
117.9(3)
126.8(3)
124.6(3)
125.8(3)
125.6(3)
97.84(3)
128.2(1)
118.2(2)
117.7(2)
124.53(19)
127.30(19)
129.1(2)
124.4(2)
97.16(2)
127.70(2)
118.31(10)
117.09(10)
123.80(10)
128.30(10)
125.02(12)
127.38(12)
C(1)–C(14)–C(23)
C(14)–C(23)–C(24)
C(2)–C(1)–C(14)
C(13)–C(1)–C(14)
C(23)–C(24)–C(25)
C(23)–C(24)–C(a0)
a Data from [5].
b Centroid of C(1, 2, 7, 8, 13).
c Centroid of C(24, 25, 26, 31, 32) for 12, C(24, 25, 26, 27, 32) for 13,
C(24, 25, 26, 27, 28) for 14.
d C(b0) is C(31) for 12, C(27) for 13 and 14.
e C(a0) is C(32) for 12 and 13, C(28) for 14.
Table 3
Catalyst activities and properties of the polyethylenes produced with
12/MAO, 13/MAO and 14/MAO
Catalysta
12/MAO
13/MAO
14/MAO
Mn (g/mol)
Mw (g/mol)
Mz (g/mol)
D ¼ Mw=Mn
A (103 kg(PE)/g(Zr)*h)
Tm (°C)
93,475
322,700
1,107,500
3.45
147,000
555,240
8,757,400
3.78
126,740
765,650
8,587,100
6.04
255.4
140.6
160.1
55
306.9
141.8
139.5
145.4
DHm (J/g)
135.3
47
132.8
46
a (%)b
a Polymerisation conditions: 60 °C, 250 ml pentane, 1 ml TIBA (1 M
in hexane), 1 h, 10 bar ethylene pressure, MAO-Al:Zr ratio ¼ 2500:1.
b Degree of crystallinity: a ¼ DHm=DHm;0 ðDHm;0 ¼ 290 J/g: en-
thalpy of fusion for 100% crystalline PE).
uminium (TIBA), displayed good activities for ethylene
polymerisation. The results are summarized in Table 3.
The addition of TIBA (as a routine method) was used to
increase catalyst activities [21]. This is thought to be due
to bulky isobutyl substituents being transferred from
TIBA to the MAO cages in the activation process. As a
consequence, the generated MAO anions become more
bulky and the separation of the catalyst cation and
MAO anion favours higher activity [22]. An obvious

1970
H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
Table 5
Pentad, triad and diad distributions (in %) of the polypropylenes by
13C NMR (62.9 MHz) spectroscopya
Catalyst
12/MAO
13/MAO
14/MAO
mmmm
mmmr
rmmr
mmrr
rmrr + mmrm
mrmr
rrrr
2.71
7.46
43.96
18.72
0.00
0.25
0.85
5.64
2.43
6.40
11.55
25.83
13.45
11.34
15.60
6.42
19.94
5.33
0.00
7.78
0.75
2.00
5.60
66.03
15.52
0.00
mrrr
mrrm
mm
4.44
15.81
50.83
33.37
41.23
58.77
62.68
25.27
12.04
73.32
24.68
3.53
Fig. 4. Dependence of the polymerisation activity of 12/MAO on the
MAO-aluminium to zirconium ratio. Polymerisation conditions: 60
°C, 250 ml pentane, 1 ml TIBA (1 M in hexane), 1 h, 10 bar ethylene
pressure, MAO-Al:Zr ratio ¼ 2500:1 up to 7500:1.
mr
rr
14.93
81.55
10.99
89.01
m
r
a Triad and diad distributions calculated from the corresponding
pentad distribution.
2.3.2. Propylene polymersation
The propylene polymerisations were carried out as
bulk polymerisations in neat propylene. The results are
summarized in Table 4. The relative activities of 12/
MAO, 13/MAO and 14/MAO show an opposite be-
haviour to the case of ethylene polymerisation. While
catalyst 13/MAO possesses the highest activity in eth-
ylene polymerisation, it has the lowest activity in bulk
polymerisation of propylene; conversely, catalyst 14/
MAO is the least active catalyst in ethylene polymeri-
sation, but the most active catalyst for propylene poly-
merisation. We interpret this result in a way that steric
factors around the active centre clearly dominate elec-
tronic factors. The molecular weights of the produced
polypropylenes were determined by viscometry. The
trend in molecular weights of the polypropylenes was
found to parallel the polymerisation activities of the
catalysts.
tions of both cyclopentadienyl moieties leads to the lack
of a preferential orientation for the growing polymer
chain and subsequent low enantiofacial discrimination
for propylene coordination and insertion. Complex 14
produces syndiotactic polypropylene with [rrrr] ¼ 66.0%.
By way of comparison, the catalyst 1,2-ethylidene(cy-
clopentadienyl)(9-fluorenyl)ZrCl2 (15)/MAO has been
reported by Razavi et al. [28] to produce syndiotactic
polypropylene with [rrrr] ¼ 74.3% under bulk polymer-
isation conditions at 60 °C. This catalyst has also been
examined by Lee et al. [29] for the polymerization of
propylene at 1.2 atm pressure in toluene solution; at 25
°C, [rrrr] ¼ 63.7%, while at 50 °C, [rrrr] ¼ 28.4%. Con-
sistent with the comparable stereospecificity of the
complexes, the geometry around the metal in complexes
ꢀ
The tacticities of the polypropylenes, determined by
13C NMR spectroscopy [26], are given in Table 5, and
are in accord with expectations based on the symmetry
and substitution pattern of the complexes [27]. Of the
two Cs-symmetric complexes, only complex 14 produces
moderately syndiotactic polypropylene. The polypro-
pylene obtained using complex 12 is substantially atac-
tic, although with a small racemic diad excess (17.5%).
Presumably the presence of substituents at all b-posi-
14 and 15 {Zr–Flu(centroid) ¼ 2.28(2) A, Zr–Cp(cen-
ꢀ
troid) ¼ 2.19(0) A, centroid–Zr–centroid ¼ 126.9(3)°
[29]} is similar.
The C1-symmetric complex 13 produces isotactic
polypropylene with [mmmm] ¼ 44.0% under bulk poly-
merisation conditions. Rieger et al. [30] have reported
the polymerisation of propylene using complexes related
to 13 with an ethylene bridge or substituted ethylene
bridge. In the case of catalysis by 1,2-ethylidene(9-flu-
orenyl)(1-indenyl)ZrCl2/MAO, isotactic polypropylene
with [mmmm] ¼ 68.1% was obtained at 50 °C and a
propylene concentration of 0.45 mol/l in toluene; the
isotacticity falls at higher propylene concentrations,
with [mmmm] ¼ 37.5% at 3.38 mol/l. For the more
stereorigid catalyst (RR,SS)-[1-(9-fluorenyl)-1-phenyl-2-
(1-indenyl)ethane]ZrCl2 (16)/MAO, isotactic polypro-
pylene with [mmmm] ¼ 80.4% was obtained at 50 °C and
a propylene concentration of 0.45 mol/l in toluene, and
[mmmm] ¼ 46.5% at 3.38 mol/l. The solid state structure
of the substituted ethylene bridge complex 16 has been
determined [30], and consistent with the comparable
Table 4
Catalyst activities and properties of the polypropylenes produced with
12/MAO, 13/MAO and 14/MAO
Catalysta
12/MAO
13/MAO
14/MAO
Mg (kg/mol)
A (kg(PP)/g(Zr)*h)
Tm (°C)
61
29.6
29
13.4
150
149.6
101.8
5.16
Amorphous
Amorphous
Amorphous
Amorphous
DHm (J/g)
a Polymerisation conditions: bulk polymerisation, 60 °C, 500 ml
propylene, 1 ml TIBA (1 M in hexane), 1 h, MAO-Al:Zr-ratio ¼
2500:1.

H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
1971
stereospecificity of this complex with that observed with
complex 13 (the concentration of propylene being ca. 10
mol/ls under bulk conditions at 60 °C [31]), the geometry
around the metal in complexes 13 and 16 {Zr–Flu(cen-
formamide were obtained by distillation from calcium
hydride. Zirconium tetrachloride was sublimed imme-
diately prior to use at ca. 195 °C/0.3 mm Hg. The MAO
used in the polymerisations was obtained from Witco,
Bergkamen, Germany. Flash chromatography was per-
formed using Merck Kieselgel 60 silica gel (particle size
0.040–0.063 mm) with the indicated solvents. Melting
points of compounds were determined on a Reichert hot
stage microscope and are uncorrected. Microanalyses
were carried out by the Microanalytical Laboratory,
University of Otago (Dunedin, New Zealand), or the
Microanalytical Laboratory, University of New South
ꢀ
ꢀ
troid) ¼ 2.259 A, Zr–Ind(centroid) ¼ 2.226 A, centroid–
Zr–centroid ¼ 127.3° [30]} is similar.
3. Conclusions
It is very difficult to predict the performance of a
metallocene catalyst because too many known and un-
known parameters have an influence on the polymeri-
zation kinetics such as the structure of a catalyst, the
activation process with MAO, the interactions of
the catalyst cation with the solvent, the monomer and
the generated polymer chain. This situation justifies the
investigation of ‘‘structure–property-relationships’’ in
order to tailor catalysts. For this purpose only one
parameter should be varied. In this study we could show
that an indenyl moiety in a bridging ligand increases the
activity in ethylene polymerization considerably com-
pared with a cyclopentadienyl unit. Steric hindrance
does not play a major role: the catalyst 13/MAO with a
1-indenyl moiety shows only a slightly better activity
than the 2-indenyl analog 12/MAO. The situation
changes in propylene polymerization: the catalyst 14/
MAO with a cyclopentadienyl unit performs much
better (factor 11.2) than the 1-indenyl derivative 13/
MAO. It is tempting to speculate that steric reasons are
responsible for this effect. Indeed, the bulkiness of a
catalyst cannot only control the kinetics of the first step,
the coordination of the olefin to the metal, but also the
orientation of the growing polymer chain. The tacticity
of the produced polypropylene is determined from the
symmetry of the catalysts. In the case of the Cs-sym-
metric complexes, 12/MAO produces atactic polypro-
pylene, while with 14/MAO syndiotactic polypropylene
is obtained analogous to the classical example with
C1-bridging, isopropylidene(cyclopentadienyl)(fluorenyl)-
ZrCl2 [32]. In the case of the C1-symmetric catalyst 13/
MAO the production of isotactic polypropylene is ob-
served, presumably through a ‘‘stationary insertion’’
mechanism [33].
1
Wales (Sydney, Australia). H (400 MHz) and 13C (100
MHz) NMR Spectra were obtained on a Bruker
1
AMX400 spectrometer. H (200 MHz) NMR Spectra
were obtained on a Bruker AC200 spectrometer. Spectra
were recorded in deuterochloroform, deuterodichlo-
romethane or deuterobenzene, as stated, and were ref-
erenced to residual CHCl3 at 7.26 ppm (1H) and 77.0
ppm (13C); CHDCl2 at 5.35 ppm (1H) and 53.8 ppm
(13C); or C6HD5 at 7.15 ppm (1H) and 128.0 ppm (13C)
downfield from TMS, respectively. Signals are assigned
as: s, singlet; d, doublet; t, triplet; q, quartet; m, multi-
plet; br broad. Coupling constants, J, are quoted in
Hertz. Mass spectra were determined on an AEI Kratos
MS902 spectrometer using electron impact ionisation
(70 eV) calibrated with perflourokerosene, and an MSS
MASPEC data system used to obtain high resolution
spectra. Infra-red spectra were recorded using a Perkin-
Elmer 1600 Fourier Transform infra-red spectrometer.
The determination of molecular weights (Mn, Mw and
Mz) and polydispersities (D) of polyethylene samples was
carried out by high temperature gel permeation chro-
matography. A Waters 150CV+ apparatus with refrac-
tive index detection was used for the measurements, with
1,2,4-trichlorbenzene as the eluting solvent at 140 °C.
The column material was polystyrene of the type
Styragel HT6E. Calibration of the instrument was car-
ried out with polystyrene standards. The determination
of Mg of polypropylene samples was carried out by
dissolving the polymers in decahydronaphthalene (iso-
meric mixture) at 130 °C. The viscosity measurements
were made using a Ubbelohde viscometer at 135 °C with
the capillary No. 0c. For the measurement of the
13C{1H} NMR spectra of the polypropylenes a Bruker
ARX 250 spectrometer was used. The polymers were
dissolved in 1,2,4-trichlorobenzene and 1,1,2,2-dideu-
tero-1,2-dichloroethane was added as a lock substance.
The samples were measured at 70 °C. Melting points
and enthalpies of fusion of the polymers were measured
with a Netsch DSC-200 instrument: 3-5 mg of the
polymer were sealed in a standard aluminum vessel
(diameter 5 mm) and the following temperature pro-
gram was used: (i) 30.0–200.0 °C at 40 °C/min, (ii)
200.0–25 °C at 30 °C/min, (iii) 30.0–180.0 °C at 10 °C/
min, (iv) 180.0–25.0 °C at 30 °C/min. Melting points and
4. Experimental
4.1. General procedures
All reactions involving moisture or air sensitive spe-
cies were carried out under a nitrogen or argon atmo-
sphere, using standard Schlenk techniques. Anhydrous
THF, ether, toluene and benzene were distilled imme-
diately prior to use from sodium-benzophenone under
nitrogen. Anhydrous dichloromethane and dimethyl-

1972
H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
melting enthalpies were determined from the curve of
program (iii). The temperature was corrected linearly to
the melting point of indium (m.p. ¼ 156.62 °C). For
calibration the melting enthalpy of indium was used
(DHm ¼ 28:45 J/g).
rapidly via cannula to a solution of the foregoing crude
ester 2 in dry dimethylformamide. The temperature was
raised to 70 °C and the mixture stirred for 18 h. The
mixture was allowed to cool to 30 °C, then diluted with
water until cloudy, seeded with crystals of sulfide 3 and
cooled slowly to 5 °C. The crystallised product was fil-
tered off, and the crystals washed with water and etha-
nol, affording the sulfide 3 (54.7 g, 0.170 mol, 85% from
acid 1) as light brown crystals, m.p. 70.5–72 °C (Found:
C, 74.2; H, 5.4. C20H18O2S requires C, 74.5; H, 5.6%);
4.2. Synthesis of complexes 12, 13 and 14
4.2.1. Isopropyl 1-bromonaphthalene-2-carboxylate 2
Thionyl chloride (145 ml) was added to an ice-cooled
solution of 1-bromo-2-naphthoic acid 1 [10] (50.0 g,
0.199 mol) in a mixture of dry benzene (200 ml), and
pyridine (16 ml, 1 equivalents). The mixture was then
allowed to warm to room temperature, and stirred for
18 h before dilution with an equal volume of dry ben-
zene and evaporation in vacuo. Residual thionyl chlo-
ride was removed by azeotropic distillation with 3
further portions of dry benzene. The acid chloride thus
obtained was taken up in dry dichloromethane (200 ml)
and placed under a nitrogen atmosphere. Pyridine (32
ml, 0.40 mol, 2 equivalents) was added, the solution
cooled in a water bath, and isopropanol (30 ml, 0.38
mol, 2 equivalents) added cautiously. The mixture began
to reflux spontaneously for a short period and was
stirred for 1 h. The mixture was then washed with hy-
drochloric acid (2 M) to remove pyridine, followed by
sodium hydroxide solution (2 M) to remove any unre-
acted acid. Drying over sodium sulfate and evaporation
in vacuo afforded the ester 2 (53 g) as a brown oil, which
was used without further purification. An analytical
sample was prepared by flash chromatography, eluting
with 20% EtOAc-light petroleum, followed by vacuum
distillation (Found: C, 57.5; H, 4.2. C14H13BrO2
requires C, 57.4; H, 4.5%); mmax(thin film)/cmꢁ1 1729
(C@O); dH(400 MHz, CDCl3) 1.44 [6H, d, J 6.3,
CH(CH3)2], 5.36 [1H, septet, J 6.3, CH(CH3)2], 7.56–
7.67 (2H, m, 6- and 7-H), 7.63 (1H, d, J3;4 8.4, 3-H), 7.82
(1H, br d, J4;3 8.4, 4-H), 7.83 (1H, br d, J5;6 8.2, 5-H) and
8.44 (1H, br d, J8;7 8.5, 8-H); dC(100 MHz, CDCl3) 167.8
[CO2CH(CH3)2], 135.7, 132.94 and 132.92 (each C),
129.1, 128.9, 128.7, 128.6, 128.5 and 126.3 (each CH),
122.7 (C), 70.4 [CO2CH(CH3)2] and 22.5 [CO2CH
(CH3)2]; m=z 294 (Mþ, 15%), 292 (Mþ, 15), 252 (30), 250
(31), 235 (37), 233 (39), 207 (14), 205 (16), 127 (28), 126
(100), 76 (15), 75 (15) and 74 (17).
m
max(KBr)/cmꢁ1 1732 (C@O); dH(400 MHz, CDCl3) 1.27
[6H, d, J 6.3, CH(CH3)2], 5.27 [1H, septet, J 6.3,
CH(CH3)2], 7.04–7.17 (5H, m, Ph-H), 7.50–7.56 (2H, m,
6- and 7-H), 7.64 (1H, d, J3;4 8.4, 3-H), 7.88 (1H, br d,
J5;6 8.0, 5-H), 7.97 (1H, br d, J4;3 8.4, 4-H) and 8.52 (1H,
br d, J8;7 8.4, 8-H); dC(100 MHz, CDCl3) 168.9
[CO2CH(CH3)2], 139.8, 138.7, 135.3 and 135.2 (each C),
131.2 (CH), 129.5 (2 ꢂ CH), 129.2 and 128.6 (each CH),
128.2 (C), 128.1 (CH), 127.81 (2 ꢂ CH), 127.76, 126.0
and 125.1 (each CH), 70.2 ([CO2CH(CH3)2] and 22.4
[CO2CH(CH3)2]; m=z 322 (Mþ, 56%), 280 (24), 263 (24),
235 (28), 234 (75), 202 (21), 188 (11), 187 (100), 186 (41),
115 (18) and 77 (14).
4.2.3. Isopropyl rac-1-(phenylsulfinyl)naphthalene-2-car-
boxylate 4
A solution of the sulfide 3 (50.0 g, 0.155 mol) in
acetonitrile (775 ml) was cooled to 0 °C. A sodium
EDTA solution (620 ml, 5 ꢂ 10ꢁ4 M) was added, fol-
lowed by acetone (135 ml, 1.84 mol, 12 equivalents),
sodium hydrogen carbonate (24 g, 0.286 mol) and OX-
ONEÒ (48 g, 0.155 mol of KHSO5). The bulk of the
sulfide precipitated from solution and the liquid became
bi-phasic. The suspension was stirred vigorously at 4–8
°C for 2 h, then a further equivalent of OXONEÒ (48 g)
and sodium hydrogen carbonate (24 g) were added, and
vigorous stirring continued for a further 7 h. The reac-
tion was then quenched by addition of sufficient 2 M
hydrochloric acid to dissolve the inorganic matter (ꢄ1 l).
The acetonitrile was then removed in vacuo, and the
precipitated product was filtered off, and washed with
water. Recrystallisation from benzene afforded the pure
sulfoxide 4 (45.2 g, 0.134 mol, 86%), m.p. 99.5–100.5 °C
(Found: C, 70.7; H, 5.2. C20H18O3S requires C, 71.0; H,
5.4%); mmax(KBr)/cmꢁ1 1704 (C@O), 1042 (S@O);
dH(400 MHz, CDCl3) 1.41 and 1.42 [each 3H, d, J 6.2,
CH(CH3)2], 5.35 [1H, septet, J 6.2, CH(CH3)2], 7.36–
7.46 (4H, m, 30-, 40-, 50- and 7-H), 7.51 (1H, br dd, J6;5
8.0, J6;7 6.8, 6-H), 7.74 (1H, d, J3;4 8.5, 3-H), 7.81 (2H,
m, 20- and 60-H), 7.86 (1H, br d, J5;6 8.0, 5-H), 8.00 (1H,
br d, J4;3 8.5, 4-H) and 8.74 (1H, br d, J8;7 8.6, 8-H); dC
(100 MHz, CDCl3) 167.2 [CO2CH(CH3)2], 145.0, 140.0,
136.2 and 134.1 (each C), 133.3 and 130.6 (each CH),
130.1 (C), 129.5 (3 ꢂ CH), 128.7, 128.5 and 126.3 (each
CH), 125.9 (2 ꢂ CH), 124.7 (CH), 71.3 [CO2CH(CH3)2]
and 22.5 [CO2CH(CH3)2]; m=z 338 (Mþ, 24%), 279 (36),
4.2.2. Isopropyl 1-(phenylsulfanyl)naphthalene-2-carbox-
ylate 3
Sodium hydride (9.6 g, 60% in paraffin oil, 0.240 mol,
1.2 equivalents) was placed under a nitrogen atmo-
sphere, washed 4 times with dry light petroleum and
dried under vacuum. The flask was cooled in an ice bath
and dry dimethylformamide (125 ml) added before
dropwise addition of thiophenol (24.6 ml, 0.240 mol, 1.2
equivalents) (vigorous evolution of hydrogen). The
mixture was then stirred for 15 min at 0 °C, then added

H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
1973
278 (31), 234 (66), 219 (29), 204 (29), 203 (100), 202 (95),
143 (46), 126 (57), 115 (56) and 77 (38).
was stirred at )78 °C for 15 min after addition of the
Grignard reagent was complete, then allowed to warm
slowly to room temperature and stirred for 18 h. The
reaction was quenched with ammonium chloride solu-
tion (10%, 150 ml). The phases were then separated, and
the aqueous phase extracted with ether. The combined
organic phases were dried over sodium sulfate and
evaporated in vacuo to leave a pale yellow crystalline
solid. Recrystallisation from dichloromethane-light pe-
troleum afforded the pure alcohol 6 (6.68 g, 15.7 mmol,
75%) as colourless crystals, m.p. 199.5–201.5 °C (Found:
C, 90.5; H, 5.7. C32H24O requires C, 90.5; H, 5.7%);
4.2.4. Isopropyl sp-1-(90-fluorenyl)naphthalene-2-carbox-
ylate 5
A solution of fluorenyllithium was prepared by add-
ing n-butyllithium (7.1 ml, 2.5 M in hexane, 17.8 mmol,
1.2 equivalents) to a solution of fluorene (2.95 g, 17.8
mmol, 1.2 equivalents) in dry THF (100 ml) at 0 °C
under nitrogen, and stirring for 5 min. A solution of the
sulfoxide 4 (5.0 g, 14.8 mmol) in dry THF (15 ml) was
then added rapidly via cannula, and the mixture, which
turned dark green, was stirred for 30 min before
quenching with ammonium chloride solution (10%, 25
ml). The phases were separated and the aqueous phase
extracted with ether. The combined organic phases were
then dried over sodium sulfate and evaporated in vacuo
to leave an orange oil. The product was purified by flash
chromatography, eluting with 5% EtOAc-light petro-
leum, and afforded the pure ester 5 (5.09 g, 13.5 mmol,
91%) as a pale yellow oil which crystallised on standing,
m.p. 124–125 °C (Found: C, 85.7; H, 5.85. C27H22O2
requires C, 85.7; H, 5.9%); mmax(KBr)/cmꢁ1 1719 (C@O);
dH(400 MHz, CDCl3) 1.42 [6H, d, J 6.2, CH(CH3)2],
5.37 [1H, septet, J 6.2, CH(CH3)2], 6.20 (1H, s, 90-H),
6.60 (1H, br d, J8;7 8.7, 8-H), 6.89 (1H, ddd, J7;8 8.7, J7;6
m
max(KBr)/cmꢁ1 3531 (OH); dH(400 MHz, CDCl3) 2.56
(1H, s, OH), 3.64 and 4.04 [each 2H, AB, JAB 16.0,
(1-H)2 and (3-H)2], 6.52 (1H, br d, J8 ;7 8.8, 80-H), 6.55
0
0
(1H, s, 900-H), 6.82 (1H, ddd, J7 ;8 8.8, J7 ;6 6.8, J7 ;5 1.4,
0
0
0
0
0
0
70-H), 7.20 (1H, ddd, J6 ;5 8.0, J6 ;7 6.8, J6 ;8 1.0, 60-H),
7.19–7.24 (6H, m, 100-, 200-, 5-, 6-, 700- and 800-H), 7.28–
7.32 (2H, m, 4- and 7-H), 7.40–7.45 (2H, m, 300- and 600-
0
0
0
0
0
0
H), 7.72 (1H, br d, J5 ;6 8.0, 50-H), 7.81 (1H, br d, J4 ;3
0
0
0
0
8.8, 40-H), 7.92 (1H, d, J3 ;4 8.8, 30-H) and 7.98 (2H, d,
0
0
J4 ;3 7.6, 400- and 500-H); dC(100 MHz, CDCl3) 150.4
00 00
(2 ꢂ C), 143.0 (C), 141.2 and 140.7 (each 2 ꢂ C), 135.7,
134.5 and 133.5 (each C), 128.66 and 128.63 (each CH),
128.0, 127.8 and 127.4 (each 2 ꢂ CH), 126.7, 126.3 and
126.0 (each CH), 125.8 (2 ꢂ CH), 124.9 (3 ꢂ CH), 121.1
(2 ꢂ CH), 86.0 (2-COH), 51.9 (900-CH) and 50.0 (1- and
3-CH2); m=z 423 ([M)H]þ, 1.3%), 409 (15), 408
([M )H2O]þ, 63), 407 (100), 406 (37) 392 (23), 390 (20),
316 (53), 304 (57), 292 (23), 291 (68) and 165 (37).
0
0
0
0
0
0
6.8, J7;5 1.3, 7-H), 7.21 (2H, ddd, J2 ;1 7.4, J2 ;3 7.4, J2 ;4
0.9, 20- and 70-H), 7.27 (2H, br d, J1 ;2 7.4, 10- and 80-H),
0
0
7.28 (1H, ddd, J6;5 8.1, J6;7 6.8, J6;8 0.8, 6-H), 7.43 (2H,
br dd, J3 ;4 7.6, J3 ;2 7.4, 30- and 60-H), 7.75 (1H, br d,
J5;6 8.1, 5-H), 7.84 and 7.85 (2H, AB, JAB 8.8, 3- and 4-
0
0
0
0
H) and 7.96 (2H, br d, J4 ;3 7.6, 40- and 50-H); dC(100
MHz, CDCl3) 170.1 [CO2CH(CH3)2], 149.2 and 140.8
(each 2 ꢂ C), 137.2, 135.8, 133.8 and 132.0 (each C),
129.0 and 128.9 (each CH), 128.1 and 127.8 (each
2 ꢂ CH), 127.4, 127.1, 126.9 and 125.7 (each CH), 125.5
and 121.0 (each 2 ꢂ CH), 70.1 [CO2CH(CH3)2], 51.7 (90-
CH) and 22.6 [CO2CH(CH3)2]; m=z 378 (Mþ, 5.5%), 336
(17) 335 (51), 319 (38), 318 (100), 290 (27), 289 (77), 288
(14), 287 (25) and 144 (12).
4.2.6. sp-1-[10-(900-fluorenyl)-20-naphthyl]indan-1-ol 7
1,2-Dibromoethane (100 ll, 1.2 mmol) was added
dropwise to a stirred suspension of magnesium granules
[20 mesh (Aldrich), 480 mg, 19.6 mmol] in dry THF
(5 ml) under an argon atmosphere. Upon cessation of
0
0
effervescence
a
solution of 1-bromo-2-(2-chloro-
ethyl)benzene [12] (1.0 g, 4.6 mmol) in dry THF (15 ml)
was added dropwise over 30 min at room temperature.
After stirring overnight, the di-Grignard solution was
added dropwise via cannula over 1 h to a solution of the
ester 5 (500 mg, 1.32 mmol) in dry THF (5 ml) at )78 °C
under an argon atmosphere. The mixture was then al-
lowed to warm slowly to room temperature over 18 h
before quenching with ammonium chloride solution
(10%, 10 ml). The phases were separated and the aque-
ous phase extracted with ether. The combined organic
phases were then dried over sodium sulfate and evapo-
rated in vacuo to leave a pale yellow oil. Flash chro-
matography eluting with 1:9:11 EtOAc–CH2Cl2–light
petroleum afforded the alcohol 7 (474 mg, 1.12 mmol,
85%) as a colourless solid, m.p. 247.5–249.5 °C; (Found:
C, 90.55; H, 5.5. C32H24O requires C, 90.5; H, 5.7%);
4.2.5. sp-2-[10-(900-fluorenyl)-20-naphthyl]indan-2-ol 6
Magnesium turnings (2.92 g, 120 mmol, 4 equiva-
lents) were activated by stirring in dry THF (20 ml)
under a nitrogen atmosphere for 20 min, followed by
addition of 1,2-dibromoethane (200 ll, 2.3 mmol, 0.075
equivalents) and gentle warming. After evolution of
ethylene (effervescence) had ceased, a solution of a,a0-
dichloro-o-xylene (5.25 g, 30 mmol) in dry THF (350 ml)
was added slowly via cannula over 3 h at room tem-
perature. The mixture was then stirred for 18 h, turning
pale green. This solution was added slowly via cannula
over 90 min to a solution of the ester 5 (7.89 g, 20.8
mmol) in dry THF (100 ml) at )78 °C under a nitrogen
atmosphere. The di-Grignard reagent began to precipi-
tate when the addition was ꢄ2/3 complete. The mixture
m
max(KBr)/cmꢁ1 3538 (OH); dH(400 MHz, CDCl3) 2.37
(1H, s, OH), 2.70–2.77 (1H, m, 2-H), 2.95–3.03 (1H, m,
0
0
2-H), 3.12–3.21 [2H, m, (3-H)2], 6.51 (1H, br d, J8 ;7 8.7,

1974
H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
80-H), 6.56 (1H, s, 900-H), 6.81 (1H, ddd, J7 ;8 8.7, J7 ;6
(5H, m, 60-, 100-, 200-, 700- and 800-H), 7.40 (2H, br dd, J3 ;2
0
0
0
0
00 00
6.7, J7 ;5 1.3, 70-H), 7.07 (1H, br d, J8 ;7 7.5, 800-H), 7.15
7.5, J3 ;4 7.5, 300- and 600-H), 7.71 (1H, br d, J5 ;6 8.1, 50-
0
0
00 00
00 00
0
0
(1H, ddd, J7 ;6 7.5, J7 ;8 7.5, J7 ;5 0.9, 700-H), 7.18 (1H,
H), 7.82 (1H, br d, J4 ;3 8.9, 40-H), 7.95 (2H, d, J4 ;3 7.5,
00 00
00 00
00 00
0
0
00 00
ddd, J6 ;5 8.2, J6 ;7 6.7, J6 ;8 0.9, 60-H), 7.24 (1H, ddd,
400- and 500-H) and 8.09 (1H, d, J3 ;4 8.9, 30-H); dC(100
MHz, CDCl3) 150.0 (2 ꢂ C), 145.2 (C), 140.7 (2 ꢂ C),
134.4, 133.9 and 133.2 (each C), 129.4 (2 ꢂ CH), 128.7
and 128.5 (each CH), 128.0 and 127.5 (each 2 ꢂ CH),
126.4, 126.2 and 125.8 (each CH), 124.9 (2 ꢂ CH), 124.5
(CH), 121.2 (2 ꢂ CH), 83.6 (1-COH), 52.2 (2- and 5-
CH2) and 51.4 (900-CH); m=z 374 (Mþ, 1.4%), 372 (2),
356 (100), 341 (12), 339 (12), 328 (33), 315 (54), 302 (13),
289 (35), 178 (16) and 165 (23).
0
0
0
0
0
0
0
0
J2 ;1 7.5, J2 ;3 7.5, J2 ;4 1.1, 200-H), 7.25 (1H, d, J3 ;4 8.6,
00 00
00 00
00 00
0
0
30-H), 7.36–7.44 (5H, m, 300-, 4-, 5-, 6- and 600-H), 7.45
(1H, br d, J1 ;2 7.5, 100-H), 7.52–7.56 (1H, m, 7-H), 7.64
00 00
(1H, br d, J4 ;3 8.6, 40-H), 7.68 (1H, br d, J5 ;6 8.2, 50-H),
0
0
0
0
7.95 (1H, br d, J5 ;6 7.5, 500-H) and 7.96 (1H, br d, J4 ;3
7.5, 400-H); dC(100 MHz, CDCl3) 149.7 (2 ꢂ C), 148.7,
143.8, 143.6, 140.03, 139.96, 134.4, 133.7 and 132.8
(each C), 128.7, 128.0, 127.4, 127.3, 127.1, 127.0, 126.7,
126.6, 125.9, 125.5, 125.4, 125.3, 125.2, 124.9, 124.8,
124.0, 120.3 and 120.2 (each CH), 87.5 (1-COH), 51.4
(900-CH), 45.3 (3-CH2) and 30.1 (2-CH2); m=z 406
([M)H2O]þ, 100%), 405 (57), 404 (19), 389 (24), 318
(22), 315 (41), 289 (22), 278 (25), 241 (28), 228 (20) and
165 (23).
00 00
00 00
4.2.8. sp-9-[20-(200-indenyl)-10-naphthyl]fluorene 9
A solution of the alcohol 6 (7.33 g, 17.3 mmol) and p-
toluenesulfonic acid (150 mg, 0.79 mmol, 5 mol%) in
benzene (250 ml) was refluxed for 20 min in a Dean-
Stark apparatus for azeotropic removal of water. The
solution was allowed to cool, then the solvent was re-
moved in vacuo and replaced with dichloromethane (200
ml). The solution was then washed with water, dried
over sodium sulfate, and evaporated in vacuo to leave
an off-white crystalline solid. Recrystallisation from
benzene afforded the pure hydrocarbon 9 (6.53 g, 16.6
mmol, 93%) as colourless crystals, m.p. 263.5–264.5 °C;
(Found: C, 94.3; H, 5.4. C32H22 requires C, 94.5; H,
5.5%); dH(400 MHz, CDCl3) 3.96 [2H, s, (100-H)2], 5.96
4.2.7. sp-1-[10-(900-fluorenyl)-20-naphthyl]-3-cyclopente-
nol 8
1,2-Dibromoethane (90 ll, 1.0 mmol) was added
dropwise to a stirred suspension of magnesium powder
[50 mesh (Aldrich), 540 mg, 22.2 mmol] in dry THF (5
ml) under an argon atmosphere. Upon cessation of ef-
fervescence the reaction was cooled to 0 °C and a so-
lution of 1,4-dibromo-2-butene (1.13 g, 5.28 mmol) in
dry THF (100 ml) was added dropwise over 1 h. The
mixture was then allowed to warm slowly to room
temperature over 18 h, affording a pale green suspen-
sion. A solution of MgBr2 in THF was prepared by
adding 1,2-dibromoethane (1.04 ml, 12.1 mmol) drop-
wise to a stirred suspension of magnesium powder [50
mesh (Aldrich), 580 mg, 23.9 mmol] in dry THF (100
ml) under an argon atmosphere. After stirring 1 h at
room temperature, this solution was added via cannula
to the pale green suspension, resulting in dissolution of
the suspension and formation of a pale green solution.
This solution was then added dropwise via cannula over
1.5 h to a solution of the ester 5 (1.00 g, 2.65 mmol) in
dry THF (10 ml) at )78 °C under an argon atmosphere.
The mixture was then allowed to warm slowly to room
temperature over 24 h before quenching with ammo-
nium chloride solution (10%, 50 ml). The phases were
separated and the aqueous phase extracted with ether.
The combined organic phases were then dried over so-
dium sulfate and evaporated in vacuo to leave a pale
yellow oil. Flash chromatography eluting with 20%
EtOAc-light petroleum afforded the alcohol 8 (310 mg,
(1H, s, 9-H), 6.48 (1H, dd, J8 ;7 8.7, J8 ;6 1.1, 80-H), 6.86
0
0
0
0
(1H, ddd, J7 ;8 8.7, J7 ;6 6.8, J7 ;5 1.3, 70-H), 7.13 (1H, br
0
0
0
0
0
0
s, 300-H), 7.18 (1H, ddd, J5 ;4 7.4, J5 ;6 7.4, J5 ;7 1.1, 500-
H), 7.18–7.23 (4H, m, 1-, 2-, 7- and 8-H), 7.22 (1H, ddd,
00 00
00 00
00 00
J6 ;5 8.0, J6 ;7 6.8, J6 ;8 1.1, 60-H), 7.27 (1H, br dd, J6 ;5
0
0
0
0
0
0
00 00
7.4, J6 ;5 7.3, 600-H), 7.38 (1H, br d, J4 ;5 7.4, 400-H),
00 00
00 00
00 00
7.36–7.42 (2H, m, 3- and 6-H), 7.48 (1H, br d, J7 ;6 7.3,
700-H), 7.57 (1H, d, J3 ;4 8.5, 30-H), 7.74 (1H, br d, J5 ;6
0
0
0
0
8.0, 50-H), 7.81 (1H, d, J4 ;3 8.5, 40-H) and 7.91 (2H, br d,
0
0
J
4;3 7.6, J5;6 7.6, 4- and 5-H); dC(100 MHz, CDCl3) 149.6
(2 ꢂ C), 148.9, 145.6 and 144.1 (each C), 140.8 (2 ꢂ C),
139.0, 134.4, 133.8 and 132.2 (each C), 131.7, 129.0 and
128.4 (each CH), 128.0 and 127.65 (each 2 ꢂ CH),
127.58, 127.4, 126.7, 126.5, 126.1 and 125.5 (each CH),
124.8 (2 ꢂ CH), 124.3 and 121.9 (each CH), 52.2 (9-CH)
and 45.2 (100-CH2); m=z 406 (Mþ, 100%), 405 (28), 390
(19), 315 (50), 302 (36), 278 (21), 241 (25), 239 (20) and
165 (43).
4.2.9. sp-9-[20-(300-indenyl)-10-naphthyl]fluorene 10
The alcohol 7 (2.09 g, 4.93 mmol) was dehydrated
using the procedure described for the preparation of 9.
Recrystallisation from benzene–heptane afforded the
pure hydrocarbon 10 (1.44 g, 3.55 mmol, 72%) as fine
colourless crystals, m.p. 208–209.5 °C; (Found: C, 94.45;
H, 5.5. C32H22 requires C, 94.5; H, 5.5%); dH(400 MHz,
0.83 mmol, 31%) as a colourless solid, m.p. 138–139 °þC
C
1H2216O requires M ,
28
(Found: Mþ, 374.1663.
12
374.1671); mmax(KBr)/cmꢁ1 3429 (OH); dH(400 MHz,
CDCl3) 1.69 (1H, s, OH), 3.02 and 3.51 [each 2H, AB,
JAB 16.3, (2-H)2 and (5-H)2], 5.81 (2H, s, 3- and 4-H),
00 00
CDCl3, 260 K) 3.61 (1H, A part of ABX, JAB 23.7, J1 ;2
5.82 (1H, br s, 900-H), 6.40 (1H, br d, J8 ;7 8.7, 80-H), 6.78
1.9, 100-H), 3.70 (1H, B part of ABX, JAB 23.7, J1 ;2 1.9,
0
0
00 00
(1H, ddd, J7 ;8 8.7, J7 ;6 6.8, J7 ;5 1.2, 70-H), 7.12–7.20
100-H), 5.94 (1H, s, 9-H), 6.61 (1H, br d, J8 ;7 8.4, 80-H),
0
0
0
0
0
0
0
0

H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
1975
6.88 (1H, apparent t, J2 ;2 1.9, 200-H), 6.98 (1H, ddd,
chloride (325 mg, 1.39 mmol, 1.1 equivalents) in dry
benzene (5 ml) at r.t. The mixture, which turned orange
and cloudy, was then stirred for 1 h. The mixture was
filtered through Celite under argon and washed through
with dry benzene (10 ml), to give a clear orange solution.
The volume was reduced to 15 ml under vacuum, while
maintaining the temperature near r.t. The solution was
then allowed to stand overnight to allow the complex to
crystallise. The supernatant solution was then removed
via cannula and the remaining crystals dried under
vacuum. This afforded orange prisms of the complex
(393 mg, 0.694 mmol, 55%), m.p. dec. >175 °C; (Found:
C, 67.4; H, 3.5; Cl, 12.55. C32H20Cl2Zr requires C, 67.8;
00 00
J7 ;8 8.4, J7 ;6 6.9, J7 ;5 1.3, 70-H), 7.17–7.22 (2H, m, 1-
and 2-H), 7.31–7.38 (3H, m, 7-, 60- and 600-H), 7.40–7.47
(3H, m, 3-, 8- and 500-H), 7.48–7.52 (2H, m, 6- and 400-
0
0
0
0
0
0
H), 7.63 (1H, br d, J7 ;6 7.3, 700-H), 7.67 (1H, d, J3 ;4 8.4,
00 00
0
0
30-H), 7.88 (1H, br d, J5 ;6 7.8, 50-H), 7.970 (1H, br d, J4;3
0
0
7.6, 4-H), 7.971 (1H, d, J4 ;3 8.4, 40-H) and 8.01 (1H, br
d, J5;6 7.6, 5-H); dC(100 MHz, CDCl3, 295 K) 149.0,
148.7, 146.2, 145.5, 143.9, 140.2, 139.9, 136.2, 134.00
and 133.94 (each C), 132.3 (CH), 131.6 (C), 128.3 and
127.8 (each CH), 127.3 (2 ꢂ CH), 127.2, 126.9, 126.8,
126.5, 126.3, 125.7, 125.4, 125.1, 124.4, 124.2, 123.9 and
120.4 (each CH), 120.2 (2 ꢂ CH), 51.4 (9-CH), and 38.6
(100-CH2); m=z 406 (Mþ, 100%), 405 (31), 389 (14), 315
(24), 278 (13), 241 (16), 228 (10), 165 (10), 78 (14).
0
0
H, 3.6; Cl, 12.5%); (Fouþnd: Mþ, 564.0003.
12
C
1H2035Cl290Zr requires M , 563.9989); dH(400
32
MHz, C6D6) 6.03 (2H, s, 100- and 300-H), 6.86–6.96 (5H,
m, 1-, 500-, 600-, 70- and 8-H), 6.96–7.05 (3H, m, 2-, 7- and
4.2.10. sp-9-[20-(100,300-cyclopentadien-100-yl)-10-naphthyl]-
fluorene and sp-9-[20-(100,300-cyclopentadien-200-yl)-10-
naphthyl]fluorene 11
80-H), 7.23 (1H, br dd, J6 ;5 8.2, J6 ;7 6.5, 60-H), 7.30–
7.35 (5H, m, 3-, 30-, 400-, 6- and 700-H) and 7.74–7.79 (4H,
m, 4-, 40-, 5- and 50-H); dC(100 MHz, C6D6) 139.4 (20-C),
137.6 (200-C), 134.3 (10-C), 134.0 (8a0-C), 133.6 (4a0-C),
129.6 (2- and 7-CH), 129.3 (40-CH), 128.59 (50-CH),
128.53 (3a00- and 7a00-C), 127.9 (70-CH), 127.4 (60-CH),
127.1 (8a- and 9a-C), 127.0 (3C, 30-, and 3- and 6-, or 500
and 600-CH), 126.7 (500- and 600-, or 3- and 6-CH), 125.8
(400- and 700-CH), 124.97 (4- and 5-CH), 124.90 (80-CH),
124.87 (4a- and 4b-C), 122.2 (1- and 8-CH), 102.1 (100-
and 300-CH) and 100.9 (9-C); m=z 574 (2.1%), 573 (6.6),
572 (18), 571 (27), 570 (58), 569 (61), 568 (85), 567 (84),
566 (100), 565 (90) and 564 (92, each Mþ), 563 (26), 529
(29), 528 (22), 527 (35), 526 (22), 525 (28), 523 (24), 400
(23) and 263 (20).
0
0
0
0
A solution of the alcohol 8 (590 mg, 1.58 mmol) in dry
dichloromethane (15 ml) was added dropwise to a solu-
tion of N,N-diisopropylethylamine (800 ll, 4.6 mmol)
and thionyl chloride (140 ll, 1.9 mmol) dry dichlorome-
thane (15 ml) at )78 °C under an Ar atmosphere. The
mixture was then allowed to warm to room temperature
and then heated at reflux for 19 h. The solution was then
diluted with dichloromethane and washed with dilute
HCl (2 M) and water. The organic phase was dried over
sodium sulfate and evaporated in vacuo to leave a pale
yellow oil. The product was purified by flash chroma-
tography, eluting with 8% EtOAc-light petroleum, and
afforded the pure ligand 11 (338 mg, 0.95 mmol, 60%) as a
þ
12
pale yellow foam; (Found: M , 356.1560.
C
28
1H20 re-
þ
1
quires M , 356.1565); the H NMR spectrum indicated
two tautomers were present in a ratio of 63:37, dH(200
MHz, C6D6, * denotes signal for the minor tautomer)
2.77 and 3.30* [2H, each apparent q, J 1.4, (500-H)2], 6.05*
and 6.16 (1H, each s, 9-H), 6.25–6.32 and 6.34–6.39* (1H,
each m, vinyl-H), 6.48–6.52 and 6.73–6.77* (1H, each m,
vinyl-H), 6.54–6.65 (1H, m, 70-H), 6.82–7.26 (9H, m, vi-
nyl-H and Ar-H), 7.38–7.62 (3H, m, Ar-H) and 7.76 (2H,
d, J4;3 7.6, 4- and 5-H); m=z 356 (Mþ, 100%), 339 (22), 328
(43), 315 (53),178 (20) and 165 (23).
4.2.12. [10-(9-fluorenyl)-20-(100-indenyl)naphthalene]zir-
conium dichloride 13
The ligand 10 (500 mg, 1.23 mmol) was metallated
using the procedure described for the preparation of
complex 12. Crystallisation from 15 ml of dry benzene
afforded bright orange/pink microfine crystals of the
complex 13 (380 mg, 0.671 mmol, 55%), m.p. dec. >175
þ
°C; (Found: M , 563.9959.
C
32
1H2035Cl290Zr requires
12
Mþ, 563.9989); dH(400 MHz, C6D6) 6.04 (1H, d, J2 ;3
00 00
3.1, 200-H), 6.54 (1H, d, J3 ;2 3.1, 300-H), 6.73 (1H, br dd,
00 00
J6 ;7 8.6, J6 ;5 7.4, 600-H), 6.82 (1H, br d, J1;2 8.6, 1-H),
00 00
00 00
4.2.11. [10-(9-fluorenyl)-20-(200-indenyl)naphthalene]zir-
conium dichloride 12
6.87–6.92 (2H, m, 7- and 8-H), 6.99 (1H, br dd, J5 ;4 8.2
00 00
J5 ;6 7.4, 500-H), 6.99–7.06 (2H, m, 2- and 70-H), 7.07
00 00
00 00
0
0
n-Butyllithium (1.23 ml, 2.48 M in hexanes, 3.0
mmol, 2.4 equivalents) was added to a solution of the
ligand 9 (508 mg, 1.25 mmol) in dry THF (15 ml) at 0 °C
under argon, and the mixture stirred for 30 min to form
the dark red/burgundy dianion. The solvent was re-
moved under vacuum, then the residue was redissolved
in dry benzene (15 ml), and the solvent removed once
more under vacuum. The residue was then taken up in
dry benzene (15 ml) and the dark red solution (at r.t.)
added via cannula to a suspension of zirconium tetra-
(1H, br d, J7 ;6 8.6, 700-H), 7.16 (1H, br d, J8 ;7 8.6, 80-
H), 7.26 (1H, br dd, J6;5 8.6, J6;7 7.4, 6-H), 7.27 (1H, br
d, J4 ;5 8.2, 400-H), 7.34 (1H, br dd, J6 ;7 6.7, J6 ;5 8.2, 60-
00 00
0
0
0
0
H), 7.41 (1H, br d, J3 ;4 8.6, 30-H), 7.51 (1H, br dd, J3;4
0
0
8.2, J3;2 7.4, 3-H), 7.82 (1H, br d, J5;6 8.6, 5-H), 7.88 (1H,
br d, J5 ;6 8.2, 50-H), 7.90 (1H, br d, J4 ;3 8.6, 40-H) and
0
0
0
0
2
7.95 (1H, br d, J4;3 8.2, 4-H); dC(100 MHz, C6D6):
2
Two quaternary carbon signals, which are probably obscured by
the solvent peak, could not be located

1976
H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
138.6, 137.3, 135.4 and 134.7 (each C), 130.2 (CH),
129.9(C), 129.81(CH), 129.5 (C), 129.0, 128.8, 128.6,
128.0, 127.8 and 127.5 (each CH), 127.3 (2 ꢂ CH),
126.7 and 126.3 (each CH), 125.69 (C), 125.63, 125.4
and 125.2 (each CH), 124.8 (C), 123.5, 122.8 and
122.1 (each CH), 121.6 (C), 113.2 and 109.4 (each CH)
and 100.4 (9-C); m=z 573 (2.1%), 572 (7.4), 571 (12), 570
(34), 569 (26), 568 (68), 567 (61), 566 (98), 565 (70)
and 564 (100, each Mþ), 563 (16), 562 (16), 527 (18),
405 (33), 404 (49), 403 (28), 402 (19), 401 (19) and 400
(21).
4.3.2. Homogeneous polymerisation of propylene
The polymerisation of propylene was carried out as a
bulk polymerisation in neat propylene. A quantity of 5–
10 mg of the catalyst precursor was dissolved or sus-
pended in 5–10 ml of toluene and activated with the
corresponding amount of MAO solution (30 wt% in
toluene) to give a ratio of MAO-aluminium to zirco-
nium of 2500:1. A solution of TIBA (1 ml of a 1 M
solution in hexane) was added, and the solvent then
removed in vacuo. The catalyst was transferred into a 1 l
€
Buchi autoclave and propylene (500 ml) condensed into
the autoclave. The reaction mixture was then stirred for
1 h at 60 °C. The remaining propylene was then allowed
to expand and the formed polymer was dried in vacuo.
4.2.13. [10-(9-fluorenyl)-20(cyclopentadienyl)naphtha-
lene]zirconium dichloride 14
The ligand 11 (255 mg, 0.72 mmol) was metallated
using the procedure described for the preparation of
complex 12. Crystallisation from 10 ml of dry benzene
afforded bright yellow/orange microfine crystals of the
complex 14 (190 mg, 0.37 mmol, 51%), m.p. dec. >175
°C; (Found: C, 65.5; H, 3.85%. C28H18Cl2Zr requires C,
65.1; H, 3.5%); dH(400 MHz, CD2Cl2) 6.05 and 6.44
4.4. X-ray structure determinations for complexes 13 and
14
Suitable crystals of compounds 13 and 14 were grown
from C6D6 solution at room temperature. Diffraction
data for compounds 13 and 14 were obtained from a
Bruker SMART 1000 diffractometer using graphite
monochromated Mo Ka radiation generated from a
sealed tube. Room temperature data were collected for
13 by attaching a crystal to a thin glass fibre. Data for 14
were collected at 150(2) K by attaching, with Exxon
Paratone N, a single crystal to a short length of suture
fibre supported on a thin piece of copper wire inserted in
a copper mounting pin. The crystal was quenched in a
cold nitrogen gas stream from an Oxford Cryosystems
Cryostream. The data integration and reduction were
undertaken with SAINT and XPREP [34]. The data for
compound 13 were corrected for absorption using a
multi-scan correction determined with SADABS [35], and
the data for 14 were corrected with a Gaussian ab-
sorption correction [34,36]. Data reduction included the
application of Lorentz and polarisation corrections.
Subsequent computations were carried out with the
teXsan [37], WinGX [38] and XTAL [39] graphical user
interfaces. Solutions for 13 and 14 were obtained with
SIR 97 [40], and were extended and refined with SHELXL
97 [41].
The asymmetric unit of 13 contains a complex mol-
ecule and 1.5 deuterated benzene molecules, with one of
the solvate molecules being centred on an inversion site.
The benzene molecules have high thermal motion and,
or, unresolved disorder and the solvate molecule C(33)–
C(38) was constrained to planarity. The populations of
the solvates were refined to convergence and then fixed
at the first decimal place, with an occupancy of 0.7 for
C(33)–C(38) and 0.9 for C(39)–C(41). The benzene
molecules were modeled with isotropic thermal param-
eters, and the remaining non-hydrogen atoms were
modeled with anisotropic thermal parameters. The
asymmetric unit of 14 contains the complex molecule
and three deuterated benzene molecules, each of which
0
0
(each 2H, apparent t, J 2.6, Cp-H), 7.04 (1H, d, J8 ;7 8.5,
80-H), 7.17 (2H, d, J1;2 8.6, 1- and 8-H), 7.31–7.36 (3H,
m, 2-, 7- and 70-H), 7.58 (1H, dd, J6 ;5 8.3, J6 ;7 6.8, 60-
0
0
0
0
H), 7.66 (1H, d, J3 ;4 8.4, 30-H), 7.72 (2H, dd, J3;2 6.9, J3;4
0
0
8.5, 3- and 6-H), 8.09 (1H, d, J5 ;6 8.3, 50-H), 8.14 (1H, d,
0
0
J4 ;3 8.4, 40-H) and 8.21 (2H, d, J4;3 8.5, 4- and 5-H);
dC(100 MHz, CD2Cl2) 138.8, 135.7, 134.6, 134.3 and
134.1 (each C), 129.8 (2 ꢂ CH), 129.7, 128.8 and 127.5
(each CH), 127.4 (2 ꢂ C), 127.2 and 127.10 (each CH),
127.06 (2 ꢂ CH), 125.4 (2 ꢂ C), 125.0 (2 ꢂ CH), 124.5
(CH), 122.2, 120.2 and 109.5 (each 2 ꢂ CH) and 100.1
(9-C); m=z 522 (7.7%), 521 (9.1), 520 (31), 519 (22), 518
(68), 517 (42), 516 (100), 515 (49) and 514 (92, each Mþ),
481 (13), 480 (10), 479 (22), 478 (13), 477 (25), 475 (15)
and 239 (13).
0
0
4.3. Polymerisation reactions
4.3.1. Homogeneous polymerisation of ethylene
A quantity of 0.5–10.0 mg of the catalyst precursor
was dissolved or suspended in 5–10 ml of toluene and
activated with the corresponding amount of MAO so-
lution (30 wt% in toluene) to give the desired ratio of
MAO-aluminium to zirconium. A solution of TIBA (1
ml of a 1 M solution in hexane) was added, and the
solution of the activated catalyst then dissolved in pen-
tane (250 ml). The pentane solution was then transferred
€
into a 1 l Buchi autoclave and warmed up to 60 °C.
Ethylene (99.98% purified with aluminium oxide) was
then polymerised under a constant pressure of 10 bar.
After 1 h the ethylene supply was stopped and the re-
action mixture cooled to room temperature. The formed
suspension was filtered and the polymer was dried in
vacuo.

H.G. Alt et al. / Journal of Organometallic Chemistry 689 (2004) 1965–1977
1977
[16] C.K. Johnson, ORTEPII, Report ORNL-5138, Oak Ridge
National Laboratory, Oak Ridge, TN, USA, 1976.
[17] H.G. Alt, E. Samuel, Chem. Soc. Rev. 27 (1998) 323.
[18] J.L. Atwood, W.E. Hunter, D.C. Hrncir, E. Samuel, H. Alt, M.D.
Rausch, Inorg. Chem. 14 (1975) 1757.
is centred on a twofold axis. A riding atom model was
used for the hydrogen and deuterium atoms for both of
the structures.
[19] J.W. Faller, R.H. Crabtree, A. Habib, Organometallics 4 (1985)
929.
5. Supplementary material
[20] P. Burger, J. Diebold, S. Gutmann, H.U. Hund, H.H. Brintzinger,
Organometallics 11 (1992) 1319.
Crystallographic data has been deposited with the
Cambridge Crystallographic Data Centre, CCDC nos.
231233 and 231234 for compounds 13 and 14, respec-
tively. Copies of this information (but not including the
thermal parameters) may be obtained free of charge
from The Director, CCDC, 12 Union Road, Cambridge,
CB2 1EZ, UK (Fax: +44-1223-336-033; e-mail: deposit
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