Highly selective propylene dimerization catalyzed by C1- symmetric zirconocene complexes

Article abstract of DOI:10.1002/aoc.3142

A series of ethylene-bridged C₁-symmetric ansa-(3-R-indenyl) (fluorenyl) zirconocene complexes (1, 2, 3, 4, 5, 6, 7, 8, 9) incorporating a pendant arene substituent on the 3-position of indenyl ring have been synthesized. The structure of complex 4 was further confirmed by X-ray diffraction analysis. When activated with methylaluminoxane, four sterically less encumbered complexes 1, 2, 4 and 5 could catalyze the dimerization of propylene in toluene at 100°C to afford 2-methyl-1-pentene with high selectivities up to 95.7-98.4% and moderate activities of 2.00×10 ⁴ to 7.89×10⁴g (mol-Zrh)^-1. Copyright

Full text of DOI:10.1002/aoc.3142

Full Paper
Received: 3 February 2014
Revised: 19 February 2014
Accepted: 24 February 2014
Published online in Wiley Online Library: 20 April 2014
(wileyonlinelibrary.com) DOI 10.1002/aoc.3142
Highly selective propylene dimerization
catalyzed by C1-symmetric zirconocene
complexes
Wenzhong Huang, Yan Wang, Haiyan Ma* and Jiling Huang*
A series of ethylene-bridged C1-symmetric ansa-(3-R-indenyl)(fluorenyl) zirconocene complexes (1–9) incorporating a pendant
arene substituent on the 3-position of indenyl ring have been synthesized. The structure of complex 4 was further confirmed
by X-ray diffraction analysis. When activated with methylaluminoxane, four sterically less encumbered complexes 1, 2, 4 and 5
could catalyze the dimerization of propylene in toluene at 100°C to afford 2-methyl-1-pentene with high selectivities up to
95.7–98.4% and moderate activities of 2.00 × 104 to 7.89 × 104 g (mol-ZrÁh)À1. Copyright © 2014 John Wiley & Sons, Ltd.
Additional supporting information may be found in the online version of this article at the publisher’s web-site.
Keywords: zirconocene; propylene; dimerization
activation with methylaluminoxane (MAO), these complexes display
moderate activity and high selectivity for propylene dimerization,
Introduction
The products of propylene dimerization, such as 2-methyl-1-
pentene and 4-methyl-1-pentene, are important olefin oligomers
and are widely used to synthesize economically valued products,
e.g. drugs[1] and branched polymers.[2] Typically, 2-methyl-1-
pentene is effectively produced (>90% in all products) at
extremely high temperature and pressure with catalyst systems
based on alkylaluminum.[3] Considering the risk of the process,
many efforts have been devoted to the single-site transition
metal catalysts, such as nickel,[4] cobalt,[5] iron[6] or vanadium[7]
complexes with bis(imino)pyridine,[7,8] diimine[9] or phosphorus-
based[10] chelating ligands, which are capable of catalyzing
propylene dimerization under mild conditions. Unfortunately, as
described in the literature, these complexes exhibit low selectiv-
ity towards a specific dimer, in most cases giving a mixture of
hexenes, methyl pentenes and dimethyl butenes.[4–10]
Group IV metallocene complexes are well-known catalysts for
propylene polymerization,[11] and by modifying the ligands’ skel-
eton or changing the polymerization conditions the microstruc-
tures of polymer chains can be conveniently tuned. In contrast,
there are only rare examples of metallocene complexes reported
for propylene oligomerization or dimerization.[12] Kaminsky[13]
reported that, at an extremely low monomer feed rate, ethylene-
bis(tetrahydroindenyl) zirconium dichloride could dimerize propyl-
ene to 2-methyl-1-pentene with a selectivity of 99.8% in all dimeric
products. However, due to the quite low activity, the reaction time
had to be expanded to 15–24 h and no activity data were reported.
Okuda and co-workers[14] described a series of unbridged hafnocene
complexes, e.g. (iBuC5Me4)2HfCl2, which showed moderate activity
for propylene oligomerization with the percentage of 4-methyl-1-
pentene up to 61.6% in all products, indicating the crucial role of
the bulky substituent on the Cp′ ring for propylene dimerization.
Herein we report a series of ethylene-bridged C1-symmetric ansa-
(3-R-indenyl)(fluorenyl) zirconocene complexes that incorporate a
pendant arene substituent on the 3-position of indenyl ring. Upon
with 2-methyl-1-pentene almost as the only product.
Experimental
General Procedures
All manipulations were carried out under a dry argon atmosphere
using standard Schlenk techniques unless otherwise indicated.
THF, diethyl ether (Et2O), n-hexane, petroleum ether (30–60°C)
and toluene were distilled from sodium–benzophenone prior to
use. Dichloromethane (CH2Cl2) was distilled from calcium hydride
under argon. Chloroform-d was dried over calcium hydride under
argon and stored in the presence of activated 4 Å molecular
sieves. n-BuLi (in n-hexane) was purchased from Acros. MAO
(1.53 M in toluene) was purchased from Witco GmbH. Polymer-
grade ethylene was directly used for polymerization. 9-(2-
Bromoethyl)-fluorene[15] and 6,6-dimethylbenzofulvene[16] were
prepared according to literature procedures. 13C (100 MHz) and
1H (400 MHz) NMR measurements were obtained in CDCl3 solu-
tion on a Bruker Avance 400 spectrometer. Chemical shifts for
NMR spectra were referenced internally using the residual sol-
vent resonances and reported relative to TMS. Elemental analyses
for C, N and H were carried out on an Elementar III Vario EI ana-
lyzer. The products of propylene oligomerization were character-
™
ized by a GC-MS instrument (Focus DSQ , Thermo Scientific).
*
Correspondence to: Jiling Huan and Haiyan Ma, Laboratory of Organometallic
Chemistry, East China University of Science and Technology, 130 Meilong Road,
Shanghai 200237, People’s Republic of China. E-mail: jlhuang@ecust.edu.cn;
haiyanma@ecust.edu.cn
Laboratory of Organometallic Chemistry, East China University of Science and
Technology, Shanghai, 200237, People’s Republic of China
Appl. Organometal. Chem. 2014, 28, 413–422
Copyright © 2014 John Wiley & Sons, Ltd.

W. Huang et al.
1
High-resolution mass spectra were performed on a Micromass Q-
TOF Micro mass spectrometer with an ESI source (Waters,
Manchester, UK).
8.0 mmol). H NMR (400 MHz, 298 K, CDCl3): δ 7.78 (d, J = 7.6 Hz,
2H, 4,5-Flu―H), 7.54 (d, J = 7.3 Hz, 1H, 1-Flu―H), 7.45
(d, J = 7.4 Hz, 1H, 8-Flu―H), 7.41–7.30 (m, 4H, 3,5-Ph―H,
2,7-Flu―H), 7.29–7.20 (m, 5H, 2,4,6-Ph―H, 3,6-Flu―H),
7.17–7.14 (m, 1H, 7-Ind―H), 7.04 (dt, J = 7.4, 0.7 Hz, 0.7H,
6-Ind―H), 7.02 (dt, J = 7.4, 0.7 Hz, 0.3H, 6-Ind―H), 6.94
(t, J = 7.4 Hz, 0.7H, 5-Ind―H), 6.93 (t, J = 7.4 Hz, 0.3H, 5-Ind―H),
6.61 (d, J = 7.6 Hz, 0.7H, 7-Ind―H), 6.59 (d, J = 7.6 Hz, 0.3H,
7-Ind―H), 6.38 (d, J = 1.9 Hz, 0.3H, 2-Ind―CH), 6.36 (d, J = 1.9 Hz,
0.7H, 2-Ind―CH), 4.01 (t, J = 5.4 Hz, 1H, 9-Flu―CH), 3.42–3.38
(m, 1H, 1-Ind―CH2), 2.23–2.09 (m, 2H, IndCH2CH2Flu,
CH2CH2CH3), 2.02–1.92 (m, 2H, IndCH2CH2Flu, CH2CH2CH3),
1.84–1.73 (m, 1H, IndCH2CH2Flu), 1.61 (s, 2.1H, CCH3), 1.55
(s, 0.9H, CCH3), 1.48–1.39 (m, 1H, IndCH2CH2Flu), 1.18–1.04 (m, 2H,
CH2CH2CH3), 0.89–0.84 (m, 3H, CH2CH2CH3). 13C NMR (100 MHz,
Synthesis of Proligands
1-(9-Fluorenyl)-2-{1-[3-(2-(2-phenylpropyl))indenyl]}ethane (L1H2)
A solution of n-BuLi in n-hexane (36.0 ml, 2.30 mol lÀ1, 83.0 mmol)
at 0°C was added dropwise to a solution of bromobenzene
(8.0 ml, 76 mmol) in 30 ml dry Et2O. The reaction mixture was
stirred overnight at room temperature (r.t.) and then 6,6-
dimethylbenzofulvene (9.08 g, 58.0 mmol) was added dropwise.
After stirring overnight at r.t., the reaction mixture was quenched
with 50 ml aqueous ammonium chloride. The organic phase was
separated and the aqueous layer was extracted with Et2O. The
combined organic phases were dried over anhydrous MgSO4.
After filtration, the solvents were removed under vacuum. The
product of 3-[2-(2-phenylpropyl)]indene (Ind 1) was isolated via
distillation under reduced pressure as a yellow oil (128–132°C/
40 Pa, 8.3 g, 82%). This compound was analyzed by 1H NMR spec-
troscopy and was used without further purification.
298 K, CDCl3):
δ 150.3 (1-Ph―C), 148.6 (7a-Ind―C), 147.4
(3a-Ind―C), 147.01 and 146.95 (8a,9a-Flu―C), 143.5 (3-Ind―C),
141.23 and 141.20 (4a,4b-Flu―C), 133.2 (2-Ind―C), 128.1
(3,5-Ph―C), 127.0 (3,6-Flu―C), 126.8 (2,7-Flu―C), 126.6
(2,6-Ph―C), 125.7 (4-Ph―C), 125.6 (5-Ind―C), 124.30 and 124.27
(4,5-Flu―C), 124.0 (6-Ind―C), 122.6 (4-Ind―C), 122.2 (7-Ind―C),
119.83 and 119.79 (1,8-Flu―C), 48.0 (1-Ind―CH2), 47.4 (9-Flu―CH),
43.6 (CH2CCH3), 42.5 (CH2CH2CH3), 29.2 (PhCH2CH2), 26.9
(PhCH2CH2), 26.8 (CCH3), 17.7 (CH2CH2CH3), 14.8 (CH2CH2CH3).
To a solution of Ind 1 (3.46 g, 14.8mmol) in 30 ml dry Et2O at 0°C
was added dropwise a solution of n-BuLi (7.0 ml, 2.15 mollÀ1
,
15 mmol) in n-hexane. The solution was stirred at r.t. for 5 h and
then added via cannula to a solution of 9-(2-bromoethyl)-fluorene
(3.46 g, 12.7mmol) in 20 ml of dry Et2O. The reaction mixture was
stirred overnight at r.t. and then quenched with 50 ml aqueous
NH4Cl. The organic phase was separated and the aqueous layer
was extracted with Et2O. The combined organic phases were dried
(MgSO4) and filtered, and the filtrate was concentrated under
vacuum. The resulting light-yellow oil was dissolved in petroleum
ether and kept at À20°C to afford an off-white solid (4.40 g, 81.6%).
1H NMR (400 MHz, 298 K, CDCl3): δ 7.72 (d, J= 7.6 Hz, 2H, 4,5-Flu-H),
7.48 (d, J= 7.6 Hz, 1H, 1-Flu-H), 7.41 (d, J= 7.6Hz, 1H, 8-Flu-H), 7.34-
7.32 (m, 2H, 3,5-Ph-H), 7.30–7.26 (m, 4H, 2,6-Ph―H, 2,7-Flu―H),
7.23–7.18 (m, 3H, 4-Ph―H, 3,6-Flu―H), 7.13 (d, J= 6.8 Hz, 1H,
7-Ind―H), 7.00–6.92 (m, 2H, 5,6-Ind―H), 6.61 (d, J= 7.6 Hz, 1H, 4-
Ind―H), 6.33 (d, J=2.0Hz, 1H, 2-Ind―CH), 3.96 (t, J= 5.4 Hz, 1H, 9-
Flu―CH), 3.35 (t, J= 5.6 Hz, 1H, 1-Ind―CH), 2.19–2.10 (m, 1H,
CH2CH2), 1.99–1.90 (m, 1H, CH2CH2), 1.78–1.69 (m, 1H, CH2CH2),
1.63 (s, 3H, CH3), 1.62 (s, 3H, CH3), 1.45–1.36 (m, 1H, CH2CH2). 13C
NMR (100 MHz, 298 K, CDCl3): δ 151.5 (1-Ph―C), 148.7 (7a-Ind―C),
147.9 (3a-Ind―C), 147.0 and 146.9 (8a,9a-Flu―C), 143.3 (3-Ind―C),
141.22 and 141.20 (4a,4b-Flu―C), 132.1 (2-Ind―C), 128.2 (3,5-
Ph―C), 126.9 (3,6-Flu―C), 126.8 (2,7-Flu―C), 126.1 (2,6-Ph―C),
125.73 (4-Ph―C), 125.66 (5-Ind―C), 124.3 (4,5-Flu―C), 124.1
(6-Ind―C), 122.7 (4-Ind―C), 122.3 (7-Ind―C), 119.81 and 119.77
(1,8-Flu―C), 48.0 (1-Ind―CH2), 47.4 (9-Flu―CH), 40.3 (C(CH3)2),
30.0 (C(CH3)2), 29.3 (CH2CH2), 29.2 (C(CH3)2), 26.9 (CH2CH2).
1-(9-Fluorenyl)-2-{1-[3-(3-(3-phenylpentyl))indenyl]}ethane (L3H2)
Following the procedure described above, n-BuLi (43.6 ml,
2.39 mol lÀ1, 104 mmol), bromobenzene (10.0 ml, 95 mmol) and
6,6-diethylbenzofulvene (13.1 g, 71.0 mmol) were used. The prod-
uct of 3-[3-(3-phenylpentyl)]indene (Ind 3) was isolated via distil-
lation under reduced pressure as a yellow oil (106–110°C/40 Pa,
1
11.04 g, 59.0%). This compound was analyzed by H NMR spec-
troscopy and was used without further purification.
A yellow solid was produced analogously to L1H2 in 79.3%
yield (1.90 g) from Ind 3 (1.74 g, 6.63 mmol), n-BuLi (2.80 mL,
2.39 mol lÀ1, 6.69 mmol) and 9-(2-bromoethyl)- fluorene (1.44 g,
1
5.27 mmol). H NMR (400 MHz, 298 K, CDCl3): δ 7.78–7.75 (m, 2H,
4,5-Flu―H), 7.54 (d, J= 7.4Hz, 1H, 1-Flu―H), 7.44 (d, J= 7.2Hz, 1H,
8-Flu―H), 7.40–7.29 (m, 4H, 3,5-Ph―H, 2,7-Flu―H), 7.28–7.21 (m,
4H, 2,6-Ph―H, 3,6-Flu―H), 7.19 (d, J= 7.4 Hz, 1H, 7-Ind―H), 7.16–
7.14 (m, 1H, 4-Ph―H), 7.01 (m, 1H, 5-Ind―H), 6.89 (t, J= 7.4 Hz, 1H,
6-Ind―H), 6.53 (d, J= 7.7 Hz, 1H, 4-Ind―H), 6.42 (d, J= 1.9Hz, 1H, 2-
Ind―CH), 4.02 (t, J=5.4Hz, 1H, 9-Flu―CH), 3.43-3.39 (m, 1H, 1-
Ind―CH2), 2.26–2.11 (m, 3H, CH2CH3, CH2CH2), 2.09–1.94 (m, 3H,
CH2CH3, CH2CH2), 1.82–1.73 (m, 1H, CH2CH2), 1.44–1.34 (m, 1H,
CH2CH2), 0.68 (t, J= 7.4 Hz, 3H, CH2CH3), 0.65 (t, J= 7.4 Hz, 3H,
CH2CH3). 13C NMR (100 MHz, 298 K, CDCl3): δ 148.7 (7a-Ind―C),
147.5 (3a-Ind―C), 147.0 and 146.9 (8a,9a-Flu―C), 145.9 (1-Ph―C),
143.5 (3-Ind―C), 141.24 and 141.21 (4a,4b-Flu―C), 134.6 (2-Ind―C),
127.9 (3,5-Ph―C), 127.4 (3,6-Flu―C), 126.93 and 126.92 (2,7-Flu―C),
126.8 (2,6-Ph―C), 125.7 (4-Ph―C), 125.5 (5-Ind―C), 124.2
(4,5-Flu―C), 124.0 (6-Ind―C), 122.5 (4-Ind―C), 122.2 (7-Ind―C),
119.83 and 119.77 (1,8-Flu―C), 48.1 (1-Ind―CH2), 47.3
(9-Flu―CH), 47.1 (C(C2H5)), 29.3(CH2CH2), 27.4 (CH2CH3),
27.1 (CH2CH3), 26.9 (CH2CH2), 8.4 (CH2CH3), 8.2 (CH2CH3).
1-(9-Fluorenyl)-2-{1-[3-(2-(2-phenylpentyl))indenyl]}ethane (L2H2)
Following the procedure described above, n-BuLi (35.0 ml,
2.39 mol lÀ1, 84.0 mmol), bromobenzene (8.0 ml, 76 mmol) and
6-methyl-6-propylbenzofulvene (9.97 g, 54.0 mmol) were used.
The product of 3-[2-(2-phenylpentyl)]indene (Ind 2) was isolated
via distillation under reduced pressure as a yellow oil (56–60°C/
1-(9-Fluorenyl)-2-{1-[3-(2-(2-(2-methylphenyl)propyl))indenyl]}ethane (L4H2)
1
15 Pa, 7.30 g, 51.2%). This compound was analyzed by H NMR
Following the procedure described above, n-BuLi (34.8 ml,
2.39 mol lÀ1, 83.0 mmol), o-bromotoluene (10.0 ml, 83 mmol) and
6,6-dimethylbenzofulvene (6.72 g, 43.0 mmol) were used. The
product of 3-{2-[2-(2-methylphenyl)propyl]}indene (Ind 4) was
isolated via distillation under reduced pressure as an orange oil
spectroscopy and was used without further purification.
A yellow solid was produced analogously to L1H2 in 37.1%
yield (1.35 g) from Ind 2 (2.10 g, 8.00 mmol), n-BuLi (4.50 ml,
1.79 mol lÀ1, 8.00 mmol) and 9-(2-bromoethyl)- fluorene (2.17 g,
wileyonlinelibrary.com/journal/aoc
Copyright © 2014 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. 2014, 28, 413–422

Propylene dimerization catalyzed by zirconocene complexes
(110–114°C/10 Pa, 5.47 g, 51.2%). This compound was analyzed by
1H NMR spectroscopy and was used without further purification.
A yellow solid was produced analogously to L1H2 in 62.8% yield
of 3-{3-[3-(2-methylphenyl)pentyl]}indene (Ind 6) was isolated via
distillation under reduced pressure as an orange oil (114–118°C/
10 Pa, 5.60 g, 41.5%). This compound was analyzed by 1H NMR
spectroscopy and was used without further purification.
(3.04 g) from Ind 4 (3.25 g, 13.1mmol), n-BuLi (5.5ml, 2.39 mollÀ1
,
13.1 mmol) and 9-(2-bromoethyl)- fluorene (3.00 g, 11.1mmol). 1H
NMR (400 MHz, 298 K, CDCl3): δ 7.78–7.76 (m, 2H, 4,5-Flu―H), 7.60
(d, J = 7.6Hz, 1H, 3-Ph―H), 7.54 (d, J = 7.2Hz, 1H, 1-Flu―H), 7.45
(d, J = 7.2Hz, 1H, 8-Flu―H), 7.41–7.32 (m, 5H, 7-Ind-H, 2,3,6,7-Flu-H),
7.21–7.15 (m, 2H, 4,5-Ph―H), 7.04 (t, J = 7.4 Hz, 1H, 6-Ind―H), 6.97
(d, J = 7.4Hz, 1H, 4-Ind―H), 6.91 (t, J = 7.4 Hz, 1H, 5-Ind―H), 6.48
(d, J = 7.6Hz, 1H, 6-Ph―H), 6.34 (d, J = 1.6 Hz, 1H, 2-Ind―CH), 4.02
(t, J = 5.4Hz, 1H, 9-Flu―CH), 3.34 (t, J = 5.9Hz, 1H, 1-Ind―CH),
2.42–2.33 (m, 1H, CH2CH2), 2.28–2.17 (m, 1H, CH2CH2), 2.04 (s, 3H,
Ph―CH3), 1.80–1.70 (m, 1H, CH2CH2), 1.73 (s, 3H, CH3), 1.70 (s, 3H,
CH3), 1.39–1.29 (m, 1H, CH2CH2). 13C NMR (100 MHz, 298 K, CDCl3): δ
152.2 (1-Ph―C), 148.6 (7a-Ind―C), 146.94 and 146.89 (8a,9a-Flu―C),
144.9 (3a-Ind―C), 143.5 (3-Ind―C), 141.23 and 141.20 (4a,
4b-Flu―C), 137.2 (2-Ind―C), 132.2 (2-Ph―C), 130.6 (3-Ph―C),
126.9 (3,6-Flu―C), 126.8 (2,7-Flu―C), 126.3 (4-Ph―C), 126.0
(5-Ph―C), 125.9 (6-Ph―C), 125.8 (5-Ind―C), 124.23 (6-Ind―C),
124.17 (4,5-Flu―C), 122.6 (4-Ind―C), 121.3 (7-Ind―C), 119.82
and 119.77 (1,8-Flu―C), 48.1 (1-Ind―CH2), 47.4 (9-Flu―CH),
40.6 (C(CH3)2), 29.8 (CH2CH2), 29.4 (2C, C(CH3)2), 26.7 (CH2CH2),
21.4 (Ph-CH3).
A yellow solid was produced analogously to L1H2 in 67.7% yield
(1.80 g) from Ind 6 (1.97 g, 7.13 mmol), n-BuLi (2.98 ml, 2.39 mollÀ1
,
7.12 mmol) and 9-(2-bromoethyl)- fluorene (1.55 g, 5.67 mmol). 1H
NMR (400MHz, 298 K, CDCl3): δ 7.77–7.75 (m, 2H, 4,5-Flu―H), 7.58
(d, J = 7.8 Hz, 1H, 1-Flu―H), 7.54 (d, J = 7.3Hz, 1H, 8-Flu―H), 7.44
(d, J = 7.3Hz, 1H, 3-Ph―H), 7.41–7.29 (m, 4H, 2,3,6,7-Flu―H), 7.24
(m, 1H, 5-Ph―H), 7.17 (d, J = 7.4 Hz, 1H, 7-Ind―H), 7.12 (dt, J = 7.4,
0.8 Hz, 1H, 6-Ind―H), 7.00 (dt, J = 7.4, 0.7Hz, 1H, 5-Ind―H), 6.93
(d, J = 6.9Hz, 1H, 6-Ph―H), 6.84 (m, 1H, 4-Ph―H), 6.40
(d, J = 7.7 Hz, 1H, 4-Ind―H), 6.35 (d, J = 2.0 Hz, 1H, 2-Ind―CH), 4.04
(t, J = 5.4Hz, 1H, 9-Flu―CH), 3.36–3.34 (m, 1H, 1-Ind―CH2),
2.33–2.16 (m, 3H, CH2CH3, CH2CH2), 2.13–2.03 (m, 3H, CH2CH3,
CH2CH2), 1.99 (s, 3H, Ph―CH3), 1.80–1.71 (m, 1H, CH2CH2),
1.32–1.25 (m, 1H, CH2CH2), 0.66 (t, J = 7.3Hz, 3H, CH2CH3), 0.63 (t,
J = 7.3 Hz, 3H, CH2CH3). 13C NMR (100 MHz, 298K, CDCl3): δ 148.8
(1-Ph―C), 148.5 (7a-Ind―C), 146.93 and 146.86 (8a,9a-Flu―C),
143.7 (3a-Ind―C), 142.9 (3-Ind―C), 141.3 and 141.2 (4a,4b-Flu―C),
137.6 (2-Ind―C), 133.4 (2-Ph―C), 132.4 (3-Ph―C), 127.7 (4-Ph―C),
126.94 and 126.93 (3,6-Flu―C), 126.8 (2,7-Flu―C), 126.0 (5-Ph―C),
125.6 (6-Ph―C), 125.3 (5-Ind―C), 124.20 and 124.16 (4,5-Flu―C),
124.09 (6-Ind―C), 122.5 (4-Ind―C), 121.4 (7-Ind―C), 119.84 and
119.77 (1,8-Flu―C), 48.2 (1-Ind―CH2), 47.4 (9-Flu―CH), 47.0 (C
(C2H5)), 30.1 (CH2CH2), 26.8 (CH2CH2), 25.51 (CH2CH3), 25.47
(CH2CH3), 21.7 (Ph―CH3), 8.6 (CH2CH3), 8.4 (CH2CH3).
1-(9-Fluorenyl)-2-{1-[3-(2-(2-(2-methylphenyl)pentyl))indenyl]}ethane (L5H2)
Following the procedure described above, n-BuLi (44.6 ml,
1.58 mol lÀ1, 71.0 mmol), o-bromotoluene (8.0 ml, 67 mmol) and
6-methyl-6-propylbenzofulvene (6.70 g, 36.0mmol) were used.
The product of 3-{2-[2-(2-methylphenyl)pentyl]}indene (Ind 5) was
isolated via distillation under reduced pressure as an orange oil
(114–118°C/10 Pa, 6.56 g, 65.3%). This compound was analyzed by
1H NMR spectroscopy and was used without further purification.
A yellow solid was produced analogously to L1H2 in 61.3%
yield (2.21 g) from Ind 5 (2.13 g, 7.71 mmol), n-BuLi (4.30 ml,
1.79 mol lÀ1, 7.70 mmol) and 9-(2-bromoethyl)- fluorene (2.10 g,
7.69 mmol). 1H NMR (400 MHz, 298 K, CDCl3): δ 7.79–7.77 (m, 2H, 4,
5-Flu―H), 7.57–7.55 (m, 2H, 1,8-Flu―H), 7.46 (d, J = 7.1 Hz, 1H,
3-Ph―H), 7.43–7.32 (m, 4H, 2,3,6,7-Flu―H), 7.27 (m, 1H, 6-Ind―H),
7.22 (d, J =7.4 Hz, 1H, 7-Ind―H), 7.15 (m, 1H, 5-Ph―H), 7.05
(m, 1H, 4-Ph―H), 6.97 (d, J= 7.3 Hz, 1H, 6-Ph―H), 6.91
(t, J = 7.2 Hz, 1H, Ph―H), 6.46 (d, J= 7.9 Hz, 1H, 4-Ind―H), 6.34
(s, 1H, 2-Ind―CH), 4.03 (t, J = 5.2 Hz, 1H, 9-Flu―CH), 3.39–3.35
(m, 1H, 1-Ind―CH2), 2.26–2.19 (m, 2H, IndCH2CH2Flu, CH2CH2CH3),
2.08–2.00 (m, 2H, IndCH2CH2Flu, CH2CH2CH3), 2.03 (s, 3H, Ph―CH3),
1.82–1.73 (m, 1H, IndCH2CH2Flu), 1.70 (s, 3H, CCH3), 1.42–1.30
(m, 1H, IndCH2CH2Flu), 1.01–0.88 (m, 5H, CH2CH2CH3, CH2CH2CH3).
13C NMR (100 MHz, 298 K, CDCl3): δ 151.5 (1-Ph―C), 148.6
(7a-Ind―C), 147.0 and 146.9 (8a,9a-Flu―C), 143.7 (3,3a-Ind―C),
141.23 and 141.19 (4a,4b-Flu―C), 137.4 (2-Ind―C), 132.2
(2-Ph―C), 131.4 (3-Ph―C), 127.1 (4-Ph―C), 126.9 (3,6-Flu―C),
126.84 and 126.83 (2,7-Flu―C), 126.2 (5-Ph―C), 125.7 (6-Ph―C),
125.6 (5-Ind―C), 124.27 and 124.22 (4,5-Flu―C), 124.1 (6-Ind―C),
122.5 (4-Ind―C), 121.3 (7-Ind―C), 119.83 and 119.78 (1,8-Flu―C),
48.0 (1-Ind―CH2), 47.4 (9-Flu―CH), 43.8 (CH2CCH3), 41.5
(CH2CH2CH3), 29.7 (PhCH2CH2), 26.8 (PhCH2CH2), 26.7 (CCH3), 21.5
(Ph―CH3), 17.9 (CH2CH2CH3), 14.8 (CH2CH2CH3).
1-(9-Fluorenyl)-2-{1-[3-(2-(2-(2-methoxyphenyl)propyl))indenyl]} ethane (L7H2)
Following the procedure described above, n-BuLi (10.3 ml,
2.39 mol lÀ1, 24.5 mmol), 2-bromoanisole (4.59 g, 24.5 mmol) and
6,6-dimethylbenzofulvene (3.69 g, 20.0 mmol) were used. The
product of 3-{2-[2-(2-methoxyphenyl)propyl]}indene (Ind 7) was
crystallized with diethyl ether as colorless crystalline solids
(3.12 g, 59.0%) and was used without further purification.
A yellow solid was produced analogously to L1H2 in 42.1%
yield (1.24 g) from Ind 7 (1.70 g, 6.43 mmol), n-BuLi (4.00 ml,
1.60 mol lÀ1, 6.40 mmol) and 9-(2-bromoethyl)- fluorene (1.75 g,
1
6.41 mmol). This compound was analyzed by H NMR spectros-
copy and was used without further purification. 1H NMR
(400 MHz, 298 K, CDCl3): δ 7.78 (d, J = 7.2 Hz, 2H, 4,5-Flu―H),
7.54 (d, J = 7.6 Hz, 1H, 1-Flu―H), 7.49 (d, J = 7.4 Hz, 1H, 8-Flu―H),
7.43–7.37 (m, 3H, 7-Ind―H, 2,7-Flu―H), 7.33 (dt, J = 7.4, 1.2 Hz,
2H, 3,6-Flu―H), 7.24–7.20 (m, 2H, 6-Ind―H, 6-Ph―H), 7.04–7.02
(m, 1H, 5-Ind―H), 6.98–6.93 (m, 2H, 3,5-Ph―H), 6.76–6.75
(m, 1H, 4-Ph―H), 6.62 (d, J = 7.6Hz, 1H, 4-Ind―H), 6.27 (d,
J = 2.1 Hz, 1H, 2-Ind―CH), 4.03 (t, J = 5.5 Hz, 1H, 9-Flu―CH), 3.37
(s, 3H, OCH3), 3.36–3.32 (m, 1H, 1-Ind―CH2), 2.29–2.20 (m, 1H,
CH2CH2), 2.09–2.01 (m, 1H, CH2CH2), 1.80–1.68 (m, 1H, CH2CH2),
1.72 (s, 3H, C(CH3)2), 1.71 (s, 3H, C(CH3)2), 1.43–1.35 (m, 1H, CH2CH2).
1-(9-Fluorenyl)-2-{1-[3-(2-(2-(2-methoxyphenyl)pentyl))indenyl]} ethane (L8H2)
Following the procedure described above, n-BuLi (15.3 ml,
1.79 mol lÀ1, 27.4 mmol), 2-bromoanisole (5.10 g, 27.3 mmol) and
6,6-diethylbenzofulvene (3.99 g, 21.7 mmol) were used. The
product of 3-{2-[2-(2-methoxyphenyl)pentyl]}indene (Ind 8) was
recrystallized with diethyl ether as an off-white powder (3.23 g,
1-(9-Fluorenyl)-2-{1-[3-(3-(3-(2-methylphenyl)pentyl))indenyl]}ethane (L6H2)
1
51.0%). This compound was analyzed by H NMR spectroscopy
Following the procedure described above, n-BuLi (34.8 ml,
2.39 mol lÀ1, 83.0 mmol), o-bromotoluene (10.0 ml, 83 mmol) and
6,6-diethylbenzofulvene (9.0g, 49.0mmol) were used. The product
and was used without further purification.
A yellow solid was produced analogously to L1H2 in 41.3% yield
(1.23 g) from Ind 8 (1.80 g, 6.16 mmol), n-BuLi (3.85 ml, 1.60 mollÀ1
,
Appl. Organometal. Chem. 2014, 28, 413–422
Copyright © 2014 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/aoc

W. Huang et al.
1
6.16 mmol) and 9-(2-bromoethyl)- fluorene (1.68 g, 6.15 mmol). H
2.15 mol lÀ1, 5.44 mmol). The resulting suspension was stirred
for 6 h at r.t. The solvent was removed under vacuum, and the
residue was washed with 2 × 10 ml portions of dry petroleum
ether and dried under vacuum. The obtained yellow solid was
suspended in 20 ml dry Et2O and cooled to 0°C. ZrCl4 (0.67 g,
2.88 mmol) was added as solid. The orange suspension was
stirred overnight at r.t. and the solvent was removed by filtration.
The residue was extracted with dry CH2Cl2 and filtrated. The fil-
trate was concentrated and stored at À20°C to give the product
as a red crystalline solid (0.245 g, 15.4%). 1H NMR (400 MHz,
NMR (400 MHz, 298K, CDCl3): δ 7.76 (d, J = 7.4Hz, 2H, 4,5-Flu―H),
7.53 (d, J = 7.3 Hz, 1H, 1-Flu―H), 7.46 (d, J = 7.3Hz, 1H, 8-Flu―H),
7.38–7.36 (m, 3H, 7-Ind―H, 2,7-Flu―H), 7.32–7.30 (m, 2H, 3,6-
Flu―H), 7.20–7.18 (m, 2H, 6-Ind―H, 6-Ph―H), 7.00 (t, J = 7.3Hz,
1H, 5-Ind―H), 6.95–6.94 (m, 2H, 4,5-Ph―H), 6.73 (d, J = 8.0Hz, 1H,
3-Ph―H), 6.56 (d, J = 7.6Hz, 1H, 4-Ind―H), 6.22 (d, J = 1.3 Hz, 1H,
2-Ind―CH), 4.01 (t, J = 5.4Hz, 1H, 9-Flu―CH), 3.32 (m, 4H,
1-Ind―CH, OCH3), 2.28–2.16 (m, 2H, IndCH2CH2Flu, CH2CH2CH3),
2.05–1.98 (m, 2H, IndCH2CH2Flu, CH2CH2CH3), 1.80–1.69 (m, 1H,
IndCH2CH2Flu), 1.64 (s, 3H, CCH3), 1.43–1.32 (m, 1H, IndCH2CH2Flu),
1.15–1.02 (m, 2H, CH2CH2CH3), 0.85 (t, J = 7.3 Hz, 3H, CH2CH2CH3).
13C NMR (100 MHz, 298 K, CDCl3): δ 158.6 (2-Ph―C), 150.9
(7a-Ind―C), 148.6 (3a-Ind―C), 147.1 (8a,9a-Flu―C), 144.3
(3-Ind―C), 141.23 and 141.20 (4a,4b-Flu―C), 135.0 (1-Ph―C),
130.8 (2-Ind―C), 128.1 (6-Ph―C), 127.4 (4-Ph―C), 126.9
(3,6-Flu―C), 126.84 and 126.82 (2,7-Flu―C), 125.5 (5-Ind―C),
124.34 and 124.30 (4,5-Flu―C), 123.6 (6-Ind―C), 122.4 (4-Ind―C),
121.4 (7-Ind―C), 120.3 (5-Ph―C), 119.81 and 119.78 (1,8-Flu―C),
112.1 (3-Ph―C), 55.0 (OCH3), 47.9 (1-Ind―CH2), 47.5 (9-Flu―CH),
42.6 (CH2CCH3), 41.1 (CH2CH2CH3), 29.7 (PhCH2CH2), 27.1
(PhCH2CH2), 25.5 (CCH3), 17.9 (CH2CH2CH3), 14.8 (CH2CH2CH3).
298 K, CDCl3):
δ 8.07 (d, J = 8.6 Hz, 1H, 7-Ind―H), 7.92
(d, J = 8.4 Hz, 1H, 4-Flu―H), 7.88 (d, J = 8.6 Hz, 1H, 1-Flu―H), 7.78
(d, J= 8.4 Hz, 1H, 5-Flu―H), 7.68–7.65 (m, 1H, 3-Flu―H), 7.51
(d, J= 8.6 Hz, 1H, 8-Flu―H), 7.46–7.42 (m, 1H, 2-Flu―H), 7.30–7.27
(m, 1H, 6-Flu―H), 7.10–7.04 (m, 4H, 7-Flu―H, 6-Ind―H, 3,5-Ph―H),
7.01–6.96 (m, 2H, 4-Ind―H, 4-Ph―H), 6.92–6.86 (m, 3H, 5-Ind―H,
2,6-Ph―H), 6.23 (s, 1H, 2-Ind―CH), 4.74–4.66 (m, 1H, CH2CH2),
4.27–4.181 (m, 1H, CH2CH2), 4.04–3.96 (m, 2H, CH2CH2), 1.96 (s, 3H,
CH3), 1.56 (s, 3H, CH3). 13C NMR (100 MHz, 298 K, CDCl3): δ 151.0
(1-Ph―C), 128.9 (7-Ind―C), 128.6 (4b-Flu―C), 127.8 (3,5-Ph―C),
127.7 (4a-Flu―C), 127.6 (4-Flu―C), 127.1 (8a,9a-Flu―C), 126.7
(1-Flu―C), 126.1 (7a-Ind―C), 125.92 (5-Flu―C), 125.86 (3a-Ind―C),
125.7 (3-Flu―C), 125.6 (2,6-Ph―C), 125.4 (8-Flu―C), 125.1
(4-Ph―C), 124.9 (2-Flu―C), 124.8 (6-Flu―C), 124.2 (6-Ind―C), 124.1
(5-Ind―C), 123.9 (9-Flu―C), 123.2 (1-Ind―C), 123.1 (7-Flu―C),
121.6 (4-Ind―C), 121.3 (3-Ind―C), 117.5 (2-Ind―C), 41.0 (C(CH3)2),
32.2 (CH2CH2), 31.2 (CH2CH2), 30.0 (C(CH3)2), 25.6 (C(CH3)2). Anal. Calcd
for C33H28Cl2ZrÁ0.9CH2Cl2: C, 61.40; H, 4.53; found: C, 61.58; H, 4.45%.
1-(9-Fluorenyl)-2-{1-[3-(3-(3-(2-methoxyphenyl)pentyl))indenyl]} ethane (L9H2)
Following the procedure described above, n-BuLi (11.5 ml,
2.39 mol lÀ1, 27.5 mmol), 2-bromoanisole (5.09 g, 27.2 mmol) and
6,6-diethylbenzofulvene (3.99 g, 21.7 mmol) were used. The prod-
uct of 3-{3-[3-(2-methoxyphenyl)pentyl]}indene (Ind 9) was
recrystallized with diethyl ether to give an off-white powder
Ethylene-1-(9-fluorenyl)-2-{1-[3-(2-(2-phenylpentyl))indenyl]} zirconium
dichloride (2)
1
(3.23 g, 51.0%). This compound was analyzed by H NMR spec-
troscopy and was used without further purification.
Following the procedure described above, L2H2 (1.13 g,
2.49 mmol), n-BuLi (2.80 ml, 1.79 mol lÀ1, 4.97 mmol)) and ZrCl4
(0.65 g, 2.78 mmol) were reacted to afford the product as red
A yellow solid was produced analogously to L1H2 in 41.3% yield
(1.23 g) from Ind 9 (1.92 g, 6.57 mmol), n-BuLi (2.75 ml, 2.39 mollÀ1
6.57 mmol) and 9-(2-bromoethyl)- fluorene (1.55 g, 5.67 mmol) were
,
1
crystals (0.858 g, 56.3%). H NMR (400 MHz, 298 K, CDCl3): δ 8.07
1
reacted to afford the product as a yellow solid (1.27 g, 48.6%). H
(d, J = 8.4 Hz, 1H, 7-Ind―H), 7.91 (dd, J = 8.4, 2.8 Hz, 2H, 1,4-
Flu―H), 7.77 (d, J = 8.4 Hz, 1H, 5-Flu―H), 7.67 (t, J = 7.2 Hz, 1H,
3-Flu―H), 7.49 (d, J = 8.6 Hz, 1H, 8-Flu―H), 7.46 (t, J = 7.8 Hz, 1H,
2-Flu―H), 7.28 (t, J = 7.2 Hz, 1H, 6-Flu―H), 7.07–7.02 (m, 3H,
7-Flu―H, 3,5-Ph―H), 6.98-6.93 (m, 3H, 4,6-Ind―H, 4-Ph―H),
6.88 (d, J = 7.2 Hz, 2H, 2,6-Ph―H), 6.84 (t, J = 8.0 Hz, 1H, 5-Ind―H),
6.29 (s, 1H, 2-Ind―H), 4.76–4.67 (m, 1H, CH2Flu), 4.29-4.20 (m, 1H,
CH2Ind), 3.95 (dd, J = 14.7, 7.7 Hz, 2H, IndCH2CH2Flu), 2.34
(dt, J = 12.4, 4.9 Hz, 1H, CH2CH2CH3), 1.88 (s, 3H, CCH3), 1.71 (dt,
J = 12.4, 3.4 Hz, 1H, CH2CH2CH3), 1.24–1.14 (m, 1H, CH2CH2CH3),
0.72 (t, J = 7.2 Hz, 3H, CH2CH2CH3), 0.66-0.55 (m, 1H, CH2CH2CH3).
13C NMR (100 MHz, 298 K, CDCl3): δ 148.4 (1-Ph―C), 131.5
(7a-Ind―C), 128.9 (7-Ind―C), 128.3 and 127.6 (4a,4b-Flu―C),
127.5 (3,5-Ph―C), 127.4 (4-Flu―C), 126.7 (1-Flu―C), 126.5 (2,6-
Ph―C), 126.09 and 126.05 (8a,9a-Flu―C), 125.8 (3a-Ind―C), 125.5
(4-Ph―C), 125.2 (5-Flu―C), 125.1 (3-Flu―C), 124.9 (8-Flu―C),
124.6 (2-Flu―C), 124.04 (6-Ind―C), 124.02 (5-Ind―C), 123.96
(4-Ind―C), 123.3 (9-Flu―C), 123.2 (6-Flu―C), 121.8 (7-Flu―C),
121.2 (1-Ind―C), 117.4 (3-Ind―C), 103.7 (2-Ind―C), 43.9
(CH3CCH2CH2CH3), 43.4 (CH3CCH2CH2CH3), 32.5 (CH2CH2), 30.1
(CH2CH2), 21.5 (CCH3), 16.6 (CH2CH2CH3), 14.6 (CH2CH2CH3). Anal.
Calcd for C35H32Cl2Zr: C, 68.38; H, 5.25; found: C, 68.18; H, 5.09%.
NMR (400 MHz, 298 K, CDCl3): δ 7.76 (dd, J= 7.2, 2.9 Hz, 2H, 4,5-
Flu―H), 7.53 (d, J= 7.4 Hz, 1H, 1-Flu―H), 7.48–7.44 (m, 2H, 7-Ind―H,
8-Flu―H), 7.39–7.28 (m, 4H, 2,3,6,7-Flu―H), 7.21–7.16 (m, 2H, 6-
Ind―H, 6-Ph―H), 6.99–6.95 (m, 2H, 4,5-Ph―H), 6.84 (t, J= 7.5 Hz,
1H, 5-Ind―H), 6.69 (d, J= 7.5 Hz, 1H, 3-Ph―H), 6.45 (d, J= 7.6 Hz,
1H, 4-Ind―H), 6.26 (d, J= 1.9 Hz, 1H, 2-Ind―CH), 4.03 (t, J= 5.4 Hz,
1H, 9-Flu―CH), 3.35–3.33 (m, 1H, 1-Ind―CH2), 3.21 (s, 3H, OCH3),
2.34–2.20 (m, 3H, CH2CH3, CH2CH2), 2.12–1.98 (m, 3H, CH2CH3,
CH2CH2), 1.77–1.68 (m, 1H, CH2CH2), 1.33–1.24 (m, 1H, CH2CH2),
0.66–0.61 (m, 6H, C(CH2CH3)2). 13C NMR (100 MHz, 298 K, CDCl3): δ
158.6 (2-Ph―C), 148.56 (7a-Ind―C), 148.55 (3a-Ind―C), 147.06
and 147.05 (8a,9a-Flu―C), 144.3 (3-Ind―C), 141.23 and 141.21
(4a,4b-Flu―C), 133.9 (1-Ph―C), 132.3 (2-Ind―C), 128.8 (6-Ph―C),
127.3 (4-Ph―C), 126.9 (3,6-Flu―C), 126.83 and 126.81 (2,7-Flu―C),
125.4 (5-Ind―C), 124.3 and 124.2 (4,5-Flu―C), 123.5 (6-Ind―C),
122.3 (4-Ind―C), 121.2 (7-Ind―C), 120.1 (5-Ph―C), 119.80 and
119.76 (1,8-Flu―C), 112.2 (3-Ph―C), 55.0 (OCH3), 48.0 (1-Ind―CH2),
47.5 (9-Flu―CH), 45.8 (C(C2H5)), 30.0 (CH2CH2), 27.3 (CH2CH2), 25.4
(CH2CH3), 25.2 (CH2CH3), 8.54 (CH2CH3), 8.46 (CH2CH3).
Synthesis of Complexes
Ethylene-1-(9-fluorenyl)-2-{1-[3-(2-(2-phenylpropyl))indenyl]} zirconium
dichloride (1)
Ethylene-1-(9-fluorenyl)-2-{1-[3-(3-(3-phenylpentyl))indenyl]} zirconium
dichloride (3)
To a solution of L1H2 (1.16 g, 2.72 mmol) in 25 ml dry Et2O at 0°C
was added dropwise a solution of n-BuLi in n-hexane (2.53 ml,
Following the procedure described above, L3H2 (0.98 g, 2.16 mmol),
n-BuLi (1.80 ml, 2.39mol lÀ1
, 4.30 mmol) and ZrCl4 (0.54 g,
wileyonlinelibrary.com/journal/aoc
Copyright © 2014 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. 2014, 28, 413–422

Propylene dimerization catalyzed by zirconocene complexes
2.32 mmol) were reacted to afford the product as red crystals
(0.406g, 30.6%). 1H NMR (400 MHz, 298 K, CDCl3): δ 8.02 (d,
J = 8.6Hz, 1H, 7-Ind―H), 7.93 (d, J = 8.4Hz, 1H, 4-Flu―H), 7.86 (d,
J = 8.4Hz, 1H, 1-Flu―H), 7.79 (d, J = 8.4Hz, 1H, 5-Flu―H), 7.68
(t, J = 7.6Hz, 1H, 3-Flu―H), 7.58 (d, J = 7.2 Hz, 2H, 3,5-Ph―H), 7.53
(d, J = 8.6 Hz, 1H, 8-Flu―H), 7.45 (t, J = 7.6Hz, 1H, 2-Flu―H), 7.28(t,
J = 7.5Hz, 1H, 6-Flu―H), 7.21–7.14 (m, 3H, 2,4,6-Ph―H), 7.07 (t,
J = 7.6Hz, 1H, 7-Flu―H), 6.94 (t, J = 7.5 Hz, 1H, 6-Ind―H), 6.81
(t, J = 7.5Hz, 1H, 5-Ind―H), 6.40 (d, J = 8.6 Hz, 1H, 4-Ind―H), 6.13
(s, 1H, 2-Ind―H), 4.69-4.60 (m, 1H, CH2Flu), 4.22–4.13 (m, 1H,
CH2Ind), 4.00–3.93 (m, 2H, IndCH2CH2Flu), 2.64–2.54 (m, 1H,
CH2CH3), 2.10–1.99 (m, 2H, CH2CH3), 1.83–1.74 (m, 1H, CH2CH3),
0.48 (t, J = 7.4Hz, 3H, CH2CH3), 0.32 (t, J = 7.4Hz, 3H, CH2CH3). 13C
NMR (100MHz, 298 K, CDCl3): δ 144.7 (1-Ph―C), 131.4 (7a-Ind―C),
129.0 (1,4-Flu―C), 128.8 (4b-Flu―C), 128.7 (7-Ind―C), 127.8 (3,5-
Ph―C), 127.71 (4a-Flu―C), 127.66 (5-Flu―C), 126.7 (3-Flu―C),
126.4 (9a-Flu―C), 126.0 (2,6-Ph―C), 125.7 (8-Flu―C), 125.5 (8a-
Flu―C), 125.13 (6-Ind―C), 125.09 (2-Flu―C), 124.72 (4-Ph―C),
124.69 (3a-Ind―C), 123.97 (5-Ind―C), 123.95 (6-Flu―C), 123.3
(4-Ind―C), 123.1 (9-Flu―C), 121.6 (7-Flu―C), 121.1 (1-Ind―C),
117.2 (3-Ind―C), 103.9 (2-Ind―C), 49.8 (C(C2H5)), 32.3 (CH2CH2),
30.8 (CH2CH3), 30.0 (CH2CH2), 27.7 (CH2CH3), 9.3 (CH2CH3), 8.1
(CH2CH3). Anal. Calcd for C35H32Cl2Zr: C, 68.38; H, 5.25; found: C,
68.29; H, 5.23%.
0.8 Hz, 1H, 6-Flu―H), 7.08 (dt, J = 8.0, 1.0 Hz, 1H, 7-Flu―H), 7.05–
7.02 (m, 1H, 5-Ph―H), 6.98–6.93 (m, 2H, 6-Ind―H, 4-Ph―H),
6.85–6.78 (m, 2H, 4,5-Ind―H), 6.69 (dd, J = 7.4, 0.6 Hz, 1H, 3-
Ph―H), 6.35 (s, 1H, 2-Ind―H), 4.75–4.66 (m, 1H, CH2Flu), 4.28–
4.19 (m, 1H, CH2Ind), 4.00–3.93 (m, 2H, IndCH2CH2Flu), 2.20–2.15
(m, 2H, CH2CH2CH3), 1.97 (s, 3H, CCH3), 1.41 (s, 3H, Ph―CH3),
1.25–1.16 (m, 1H, CH2CH2CH3), 0.75 (t, J = 7.2 Hz, 3H, CH2CH2CH3),
0.60–0.49 (m, 1H, CH2CH2CH3). 13C NMR (100 MHz, 298 K, CDCl3): δ
144.7 (1-Ph―C), 136.5 (2-Ph―C), 132.5 (6-Ph―C), 131.8
(7a-Ind―C), 128.9 (7-Ind―C), 128.6 (1-Flu―C), 127.8 (4-Flu―C),
127.3 (4a,4b-Flu―C), 127.1 (5-Ph―C), 126.9 (5-Flu―C), 126.6
(9a-Flu―C), 126.0 (3-Flu―C), 125.8 (8a-Flu―C), 125.41 (8-Flu―C),
125.37 (6-Ind―C), 125.1 (2-Flu―C), 125.0 (6-Flu―C), 124.8
(4-Ph―C), 124.5 (5-Ind―C), 124.3 (3-Ph―C), 124.0 (4-Ind―C),
123.5 and 123.4 (9-Flu―C, 1-Ind―C), 122.0 (3a-Ind―C), 120.0
(3-Ind―C),
119.1
(7-Flu―C),
104.2
(2-Ind―C),
44.3
(CH3CCH2CH2CH3), 39.1 (CH3CCH2CH2CH3), 33.0 (CH2CH2), 29.9
(CH2CH2), 25.5 (CCH3), 22.1 (Ph―CH3), 17.3 (CH2CH2CH3), 14.7
(CH2CH2CH3). EI/HRMS: [M]+ calcd for C36H34Cl2Zr, 626.1085;
found, 626.1088.
Ethylene-1-(9-fluorenyl)-2-{1-[3-(3-(3-(2-methylphenyl)pentyl))indenyl]}
zirconium dichloride (6)
Following the procedure described above, L6H2 (0.99 g,
2.11 mmol), n-BuLi (1.77 ml, 2.39 mol lÀ1, 4.23 mmol) and ZrCl4
(0.50 g, 2.15 mmol) were reacted to afford the product as red
Ethylene-1-(9-fluorenyl)-2-{1-[3-(2-(2-(2-methylphenyl)propyl))indenyl]}zirconium
dichloride (4)
1
crystals (0.71 g, 53.1%). H NMR (400 MHz, 298 K, CDCl3): δ 8.06
Following the procedure described above, L4H2 (1.89 g,
4.29 mmol), n-BuLi (3.60 ml, 2.39 mol lÀ1, 8.60 mmol) and ZrCl4
(1.03 g, 4.42 mmol) were reacted to afford the product as red
(d, J = 8.6 Hz, 1H, 7-Ind―H), 7.89 (d, J = 8.4 Hz, 1H, 4-Flu―H),
7.87 (d, J = 8.6 Hz, 1H, 1-Flu―H), 7.76 (d, J = 8.4 Hz, 1H, 5-Flu―H),
7.66 (t, J = 7.6 Hz, 1H, 3-Flu―H), 7.54 (d, J = 8.6 Hz, 1H, 8-Flu―H),
7.47 (d, J = 8.6 Hz, 1H, 6-Ph―H), 7.42 (t, J = 7.6 Hz, 1H, 2-Flu―H),
7.29 (t, J = 7.7 Hz, 1H, 6-Flu―H), 7.10 (t, J = 5.6 Hz, 1H, 7-Flu―H),
7.08 (t, J = 5.6 Hz, 1H, 5-Ph―H), 6.98 (t, J = 7.2 Hz, 1H, 4-Ph―H),
6.93 (dd, J = 8.4, 4.0 Hz, 1H, 4-Ph―H), 6.84 (d, J = 3.6 Hz, 2H, 4,5-
Ind―H), 6.75 (d, J = 7.4 Hz, 1H, 3-Ph―H), 6.18 (s, 1H, 2-Ind―H),
4.74–4.65 (m, 1H, CH2Flu), 4.26–4.17 (m, 1H, CH2Ind), 3.95 (dd,
J = 14.6, 7.8 Hz, 2H, IndCH2CH2Flu), 2.69–2.60 (m, 1H, CH2CH3),
2.58–2.48 (m, 1H, CH2CH3), 2.39–2.30 (m, 1H, CH2CH3), 2.21–2.12
(m, 1H, CH2CH3), 1.30 (s, 3H, Ph―CH3), 1.06 (t, J = 7.3 Hz, 3H,
CH2CH3), 0.60 (t, J = 7.4 Hz, 3H, CH2CH3). 13C NMR (100 MHz,
1
crystals (0.97 g, 34.4%). H NMR (400 MHz, 298 K, CDCl3): δ 8.13
(d, J = 8.6 Hz, 1H, 7-Ind―H), 7.89 (d, J = 7.4 Hz, 2H, 1,4-Flu―H),
7.76 (d, J = 8.4 Hz, 1H, 5-Flu―H), 7.68–7.64 (m, 1H, 3-Flu―H),
7.50 (d, J = 8.6 Hz, 1H, 8-Flu―H), 7.46–7.42 (m, 2H, 2-Flu―H,
6-Ph―H), 7.30–7.26 (m, 1H, 6-Flu―H), 7.10–7.02 (m, 2H, 7-Flu―H,
5-Ph―H), 7.00–6.94 (m, 2H, 6-Ind―H, 4-Ph―H), 6.90–6.82 (m, 2H,
4,5-Ind―H), 6.75 (dd, J = 7.4, 0.6 Hz, 1H, 3-Ph―H), 6.28 (s, 1H,
2-Ind―H), 4.75–4.66 (m, 1H, CH2Flu), 4.28–4.19 (m, 1H, CH2Ind),
4.00–3.94 (m, 2H, IndCH2CH2Flu), 2.03 (s, 3H, C(CH3)2), 1.65 (s,
3H, C(CH3)2), 1.51 (s, 3H, Ph―CH3). 13C NMR (100 MHz, 298 K,
CDCl3): δ 147.5 (1-Ph―C), 136.2 (2-Ph―C), 132.6 (6-Ph―C),
131.8 (7a-Ind―C), 129.0 (7-Ind―C), 127.5 and 127.4 (4a,4b-
Flu―C), 127.2 (1-Flu―C), 127.0 (4-Flu―C), 126.5 (9a-Flu―C),
126.1 (5-Flu―C), 126.0 (3-Flu―C), 125.8 (8a-Flu―C), 125.7
(6-Ind―C), 125.6 (8-Flu―C), 125.3 (5-Ph―C), 125.0 (4-Ph―C),
124.9 (2-Flu―C), 124.5 (3-Ph―C), 124.2 (6-Flu―C), 124.0
(5-Ind―C), 123.42 (9-Flu―C), 123.40 (4-Ind―C), 123.38
(1-Ind―C), 122.0 (3a-Ind―C), 120.1 (3-Ind―C), 119.4 (7-Flu―C),
104.1 (2-Ind―C), 41.0 (C(CH3)2), 32.8 (CH2CH2), 29.9 (CH2CH2),
29.1 (C(CH3)2), 27.1 (C(CH3)2), 22.2 (PhCH3). Anal. Calcd for
C34H30Cl2ZrÁ0.25CH2Cl2: C, 66.14; H, 4.94; found: C, 66.35; H,
4.83%.
298 K, CDCl3):
δ 142.2 (1-Ph―C), 137.1 (2-Ph―C), 132.6
(6-Ph―C), 131.1 (7a-Ind―C), 129.1 (7-Ind―C), 128.8 (1-Flu―C),
127.9 (4a,4b-Flu―C), 127.6 (4-Flu―C), 126.8 (5-Flu―C), 126.3
(9a-Flu―C), 126.2 (3-Flu―C), 125.9 (5-Ph―C), 125.60 (8-Flu―C),
125.57 (8a-Flu―C), 125.2 (6-Ind―C), 125.04 (2-Flu―C), 124.98
(6-Flu―C), 124.5 (4-Ph―C), 124.0 (5-Ind―C), 123.9 (3-Ph―C),
123.6 (9-Flu―C), 123.2 (1-Ind―C), 123.0 (4-Ind―C), 121.7
(3a-Ind―C), 120.8 (3-Ind―C), 118.5 (7-Flu―C), 104.3 (2-Ind―C),
49.0 (C(C2H5)), 32.8 (CH2CH2), 31.4 (CH2CH3), 30.5 (CH2CH3), 30.0
(CH2CH2), 21.8 (Ph―CH3), 11.7 (CH2CH3), 10.2 (CH2CH3). Anal.
Calcd for C36H34Cl2ZrÁ0.5CH2Cl2: C, 65.31; H, 5.26; found: C,
65.40; H, 5.32%.
Ethylene-1-(9-fluorenyl)-2-{1-[3-(2-(2-(2-methylphenyl)pentyl))indenyl]}zirconium
dichloride (5)
Ethylene-1-(9-fluorenyl)-2-{1-[3-(2-(2-(2-methoxylphenyl)propyl))indenyl]}
zirconium dichloride (7)
Following the procedure described above, L5H2 (1.10 g,
2.35 mmol), n-BuLi (2.65 ml, 1.79 mol lÀ1, 4.74 mmol) and ZrCl4
(0.57 g, 2.45 mmol) were reacted to afford the product as red
Following the procedure described above, L7H2 (0.84 g,
1.84 mmol), n-BuLi (2.33 ml, 1.59 mol lÀ1, 3.68 mmol), and ZrCl4
(0.44 g, 1.89 mmol) were reacted to afford the product as red
1
1
crystals (0.372 g, 25.2%). H NMR (400 MHz, 298 K, CDCl3): δ 8.13
crystals (0.234 g, 20.6%). H NMR (400 MHz, 298 K, CDCl3): δ 8. 07
(d, J = 8.7 Hz, 1H, 7-Ind―H), 7.89 (d, J = 8.6 Hz, 2H, 1,4-Flu―H),
7.76(d, J = 8.4 Hz, 1H, 5-Flu―H), 7.66 (dt, J = 8.2, 1.0 Hz, 1H, 3-
Flu―H), 7.51–7.44 (m, 3H, 2,8-Flu―H, 6-Ph―H), 7.28 (dt, J = 6.9,
(d, J = 8.6 Hz, 1H, 7-Ind―H), 7.89 (t, J = 8.4 Hz, 2H, 1,4-Flu―H),
7.76 (d, J = 8.4 Hz, 1H, 5-Flu―H), 7.66 (t, J = 7.6 Hz, 1H, 3-Flu―H),
7.50 (d, J = 8.4 Hz, 1H, 8-Flu―H), 7.45 (t, J = 7.6 Hz, 1H, 2-Flu―H),
Appl. Organometal. Chem. 2014, 28, 413–422
Copyright © 2014 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/aoc

W. Huang et al.
7.28 (t, J = 7.4 Hz, 1H, 6-Flu―H), 7.22 (d, J = 8.0 Hz, 1H, 6-Ph―H),
7.08-7.01 (m, 3H, 7-Flu―H, 3,5-Ph―H), 6.94 (t, J = 7.6 Hz, 1H,
6-Ind―H), 6.86 (t, J = 7.6 Hz, 1H, 5-Ind―H), 6.82 (t, J = 8.0 Hz, 1H,
4-Ph―H), 6.55 (d, J = 8.0 Hz, 1H, 4-Ind―H), 6.26 (s, 1H, 2-Ind―H),
4.73–4.65 (m, 1H, CH2Flu), 4.27–4.19 (m, 1H, CH2Ind), 4.01–3.93
(m, 2H, IndCH2CH2Flu), 3.21 (s, 3H, OCH3), 1.97 (s, 3H, C(CH3)2),
1.68 (s, 3H, C(CH3)2). 13C NMR (100 MHz, 298 K, CDCl3): δ 157.8
(2-Ph―C), 138.0 (7a-Ind―C), 131.3 (1-Ph―C), 128.8 (1-Flu―C),
127.5 and 127.4 (4a,4b-Flu―C), 127.3 (4-Flu―C), 127.2 (7-Ind―C),
126.6 (5-Flu―C), 126.5 (3-Flu―C), 126.1 and 125.9 (8a,9a-Flu―C),
125.5 (8-Flu―C), 125.3 (6-Ph―C), 125.0 (2-Flu―C), 124.7
(6-Flu―C), 124.2 (4-Ph―C), 124.1 (6-Ind―C), 124.0 (5-Ind―C),
123.5 (3a-Ind―C), 123.20 and 123.19 (9-Flu―C,1-Ind―C), 121.7
(4-Ind―C), 120.5 (5-Ph―C), 120.2 (3-Ind―C), 119.6 (7-Flu―C),
112.4 (3-Ph―C), 103.6 (2-Ind―C), 54.8 (OCH3), 39.9 (C(CH3)2),
32.3 (CH2CH2), 30.0 (C(CH3)2), 27.1 (C(CH3)2), 26.3 (CH2CH2). Anal.
Calcd for C34H30OCl2Zr: C, 66.21; H, 4.90; found: C, 66.02; H, 4.95%.
3-Ph―H), 4.20–4.07 (m, 2H, IndCH2CH2Flu), 4.03–3.95 (m, 1H,
CH2CH2), 3.66–3.57 (m, 1H, CH2CH2), 2.20–2.11 (m, 1H, CH2CH3),
2.06–1.97 (m, 1H, CH2CH3), 1.91–1.82 (m, 1H, CH2CH3), 1.51–1.40
(m, 1H, CH2CH3), 0.53 (t, J = 7.3 Hz, 3H, CH2CH3), 0.43 (t,
J = 7.3 Hz, 3H, CH2CH3). 13C NMR (100 MHz, 298 K, CDCl3): δ 160.7
(2-Ph―C), 131.7 (7a-Ind―C), 128.4 (7-Ind―C), 127.6 (1,4-Flu―C),
127.4 (5-Flu―C), 126.8 (4a,4b-Flu―C), 126.7 (6-Ph―C), 126.5
(1-Ph―C), 125.8 (8a,9a-Flu―C), 124.9 (2,3-Flu―C), 124.8 (6,7-
Flu―C), 124.4 (8-Flu―C), 124.1 (4-Ph―C), 123.7 (6-Ind―C),
123.5 (5-Ind―C), 122.8 (3a-Ind―C), 121.7 (4-Ind―C), 120.9
(9-Flu―C,1-Ind―C), 120.4 (3-Ind―C), 119.6 (5-Ph―C), 119.2
(2-Ind―C), 101.3 (3-Ph―C), 44.0 (C(C2H5)), 28.1 (CH2CH2), 27.6
(CH2CH2), 26.6 (CH2CH3), 25.6 (CH2CH3), 8.6 (CH2CH3), 8.1
(CH2CH3). Anal. Calcd for C35H31OClZrÁ1.2CH2Cl2: C, 62.45; H,
4.84; found: C, 62.55; H, 4.97%.
General Oligomerization Procedures
Ethylene-1-(9-fluorenyl)-2-{1-[3-(2-(2-(2-methoxylphenyl)pentyl))indenyl]}
zirconium dichloride (8)
A 100 ml stainless steel autoclave equipped with a magnetic stirrer
was heated under vacuum for 1 h over 100°C, then allowed to cool
to the required temperature under propylene atmosphere, and
charged with 20ml toluene. The reactor was sealed and pressur-
ized to 6 bar of propylene pressure. Stirring for about 30 min
ensured that the solution was equilibrated and the required reac-
tion temperature was established. The propylene pressure was
then released. An appropriate amount of MAO in toluene and the
solution of zirconocene complex in 1 ml toluene were added se-
quentially. The reactor was sealed and pressurized to the required
propylene pressure. After the reaction was carried out for 0.5h,
the reactor was cooled rapidly with an ice–salt bath to quench
the further reaction and avoid any loss of possible low-boiling-
point fraction. When the reactor was completely cooled down,
the pressure was released and 1 ml of methanol was injected im-
mediately. Heptane (0.2ml) was added as internal standard. An
aliquot of the reaction solution was withdrawn, filtered and then
analyzed by GC. The residual bulk solution was quenched by the
addition of 3% HCl–ethanol and washed three times with water.
All the volatiles of the solution were evaporated to check the pro-
duction of any higher-molecular-weight oligomers.
Following the procedure described above, L8H2 (0.84 g,
1.84 mmol), n-BuLi (2.33 ml, 1.59 mol lÀ1, 3.68 mmol), and ZrCl4
(0.44 g, 1.89 mmol) were reacted to afford the product as red
1
crystals (0.234 g, 20.6%). H NMR (400 MHz, 298 K, CDCl3): δ 8. 08
(d, J = 8.6 Hz, 1H, 7-Ind―H), 7.89 (t, J = 8.8 Hz, 2H, 1,4-Flu―H),
7.75 (d, J = 8.4 Hz, 1H, 5-Flu―H), 7.66 (t, J = 7.5 Hz, 1H, 3-Flu―H),
7.48 (d, J = 8.6 Hz, 1H, 8-Flu―H), 7.45 (t, J = 7.8 Hz, 1H, 2-Flu―H),
7.38 (d, J = 7.8 Hz, 1H, 6-Ph―H), 7.29–7.25 (m, 1H, 6-Flu―H),
7.04 (t, J = 7.2 Hz, 1H, 7-Flu―H), 7.02 (t, J = 7.2 Hz, 1H, 5-Ph―H),
6.94 (d, J = 8.6 Hz, 1H, 4-Ind―H), 6.91 (t, J = 8.4 Hz, 1H, 4-Ph―H),
6.86 (t, J = 7.6 Hz, 1H, 6-Ind―H), 6.80 (t, J = 7.8 Hz, 1H, 5-Ind―H),
6.48 (d, J = 8.1 Hz, 1H, 3-Ph―H), 6.33 (s, 1H, 2-Ind―H), 4.75–4.66
(m, 1H, CH2Flu), 4.30–4.21 (m, 1H, CH2Ind), 4.00–3.90 (m, 2H,
IndCH2CH2Flu), 3.04 (s, 3H, OCH3), 2.36 (dt, J = 12.5, 4.0 Hz, 1H,
CH2CH2CH3), 2.14 (dt, J = 12.5, 4.0 Hz, 1H, CH2CH2CH3), 1.90
(s, 3H, CCH3), 1.23–1.13 (m, 1H, CH2CH2CH3), 0.74 (t, J = 7.2 Hz,
3H, CH2CH2CH3), 0.62–0.50 (m, 1H, CH2CH2CH3). 13C NMR
(100 MHz, 298 K, CDCl3): δ 158.0 (2-Ph―C), 135.7 (7a-Ind―C),
131.3 (1-Ph―C), 128.8 (6-Ph―C), 128.1 (1-Flu―C), 127.4 (4a-
Flu―C), 127.3 (7-Ind―C), 127.12 (4b-Flu―C), 127.08 (4,5-Flu―C),
127.0 (3-Flu―C), 126.9 and 126.8 (8a,9a-Flu―C), 126.7 (8-Flu―C),
125.4 (2-Flu―C), 125.1 (6-Flu―C), 125.0 (4-Ph―C), 124.7
(6-Ind―C), 124.2 (5-Ind―C), 124.1 (9-Flu―C), 123.9 (1-Ind―C),
123.2 (3a-Ind―C), 121.9 (4-Ind―C), 120.4 (5-Ph―C), 120.0
(3-Ind―C), 119.5 (7-Flu―C), 112.5 (3-Ph―C), 103.6 (2-Ind―C),
54.9 (OCH3), 43.1 (CCH3), 38.5 (CH2CH2CH3), 32.5 (PhCH2CH2),
30.0 (PhCH2CH2), 23.6 (CCH3), 17.4 (CH2CH2CH3), 14.7
(CH2CH2CH3). Anal. Calcd for C36H34OCl2ZrÁ0.1CH2Cl2: C, 66.37;
H, 5.28; found: C, 66.05; H, 5.28%.
GC-MS Analysis
GC-MS analysis was performed on an Agilent 6890GC-5975MSD
instrument (Agilent Technologies, USA). A fused silica capillary
Agilent Technologies HP-5MS (5% phenyl methyl siloxane)
column (30 m × 0.25 mm × 0.25 μm) was used for the separation.
The injection volume was 10μl. The inlet temperature was
maintained at 250°C. The column oven was held at 35°C for
2 min, and then increased to 50°C at a rate of 5.0°C minÀ1 and held
for 3 min. The linear velocity of the helium carrier gas was 1.0 ml
minÀ1 at a split ratio of 20:1. The mass spectrometer was used
under the following conditions: ion source temperature, 230°C;
scan range, m/z 10–550. The internal standard was heptane.
Components were identified by matching their recorded mass
spectra with the standard mass spectra from the National Insti-
tute of Standards and Technology (NIST05.LIB) libraries data pro-
vided by the software of the GC-MS system, literature data and
standards of the main components. The results were also con-
firmed based on their retention indices (determined with refer-
ence to a homologous series of normal alkanes) on HP-5MS
capillary column. (Jayaprakasha et al., 1997; Lazari et al., 1999;
Adams, 2001; Gallori et al., 2001; Skaltsa et al., 2003).[17]
Ethylene-1-(9-fluorenyl)-2-{1-[3-(3-(3-(2-oxy-phenyl)pentyl))indenyl]}zirconium
chloride (9)
Following the procedure described above, L9H2 (1.10 g,
2.27 mmol), n-BuLi (1.90 ml, 2.39 mol lÀ1, 4.54 mmol), and ZrCl4
(0.53 g, 2.27 mmol) were reacted to afford the product as yellow
1
crystals (0.214 g, 15.9%). H NMR (400 MHz, 298 K, CDCl3): δ 8.04
(d, J = 8.4 Hz, 1H, 7-Ind―H), 7.98 (d, J = 8.2 Hz, 1H, 4-Flu―H),
7.83 (d, J = 8.2 Hz, 1H, 1-Flu―H), 7.70 (d, J = 8.4 Hz, 1H, 5-Flu―H),
7.40 (d, J = 6.8 Hz, 1H, 6-Ph―H), 7.38–7.28 (m, 4H, 2,3,6,7-Flu―H),
7.22 (d, J = 7.7 Hz, 1H, 8-Flu―H), 6.96 (t, J = 7.7 Hz, 1H, 6-Ind―H),
6.93–6.89 (m, 1H, 5-Ind―H), 6.77–6.70 (m, 3H, 4-Ind―H,
4,5-Ph―H), 6.62 (br s, 1H, 2-Ind―H), 6.12 (d, J = 8.0 Hz, 1H,
wileyonlinelibrary.com/journal/aoc
Copyright © 2014 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. 2014, 28, 413–422

Propylene dimerization catalyzed by zirconocene complexes
Propylene Dimerization
Results and Discussion
Propylene dimerization by zirconocene complexes 1–9 in the
presence of MAO were explored. In general, C1-symmetric ansa-
(indenyl)(fluorenyl) zirconocene complexes (where indenyl,
fluorenyl could also be substituted) are well known for their
catalytic abilities of producing polypropylenes with various
tacticities.[18] However, upon activation with MAO, these
zirconocene complexes showed no activity for propylene poly-
merization or transformation in toluene at 30 and 60°C. Interest-
ingly, when the polymerization temperature was increased to
100°C, the four sterically less encumbered C1-symmetric
zirconocene complexes 1, 2, 4 and 5 could catalyze the dimeriza-
tion of propylene to produce 2-methyl-1-pentene with high se-
lectivities ranging from 95.7% to 98.4% and moderate activities.
There were no polymers or higher oligomers in the reaction
end products, but with 4-methyl-2-pentene detected as the only
byproduct. Among them, complex 4 displayed the highest dimer-
ization activity of 7.89 × 104 g (mol-ZrÁh)À1 at an Al/Zr ratio of
8000 (Table 1, run 9), while complex 5 gave the highest selectivity
for 2-methyl-1-pentene up to 98.4% (run 11). All results are listed
in Table 1, and a typical GC trace of propylene dimer obtained by
complex 4 is shown in Fig. 2.
It seems that the alkyl groups on the quaternary carbon bridge
of the substituent have a significant influence on the catalytic
performance of these zirconocene complexes. In comparison
with complexes 1, 2, 4 and 5, complexes 3 and 6 with two ethyl
groups on the quaternary carbon bridge only afforded trace
amount of propylene dimerization products under
otherwise identical conditions (runs 5 and 12). The
activities of complexes 1–3 decreased in the order 2> 1>> 3,
while for complexes 4–6 with a pendant o-methylphenyl
group activity decreased with the increase of the steric
bulkiness of the alkyl groups on the quaternary carbon.
Synthesis of Zirconium Complexes
The synthesis of substituted indene Ind1–Ind9 and the relevant
ethylene-bridged indenyl-fluorenyl proligands L1H2–L9H2 was
accomplished via a procedure reported previously.[18] According
to this method, the zirconocene complexes 1–8 were prepared
via a straightforward reaction of ZrCl4 with 1 equiv. of dilithium salt
of the corresponding ligand in diethyl ether (Scheme 1), followed
by an extraction and recrystallization in dichloromethane. In con-
trast to complexes 7 (R2 = R3 = Me) and 8 (R2 = Me, R3 = nPr) bearing
a pendant o-methoxyphenyl group on the indenyl ring, complex 9
(R2 = R3 = Et) with the same pentant group was obtained as a
zircoxacyclic structure. A similar result was previously observed in
the synthesis of titanocene complexes with analogous Cp ligands,
where the presence of bigger ethyl groups on the quaternary
carbon was suggested to promote an intramolecular elimination
of a molecule of chloromethane to form a titanoxacyclic species.[19]
All complexes 1–9 were characterized by 1H,13C NMR spectroscopy
and elemental analysis or high-resolution mass spectroscopy.
Furthermore, the molecular structure of complex 4 was deter-
mined by X-ray diffraction study. As shown in Fig. 1, the bond
lengths of Zr―C1, Zr―C2, Zr―C7, Zr―C8, Zr―C13 vary to a cer-
tain degree (2.427(2)–2.701(2) Å), which may evidence the
coordination mode of the central five-membered ring of the
fluorenyl slipping from η5 towards η3.
Br
R3
R2
R1
R3
nBuLi
Furthermore, neither complexes 7 and 8 bearing a
R2 R1
Et2O
PE
pendant o-methoxyphenyl on the indenyl ring nor the
zircoxacyclic complex 9 could show any catalytic activity
for propylene transformation. According to our previous
studies,[20] the introduction of the same type of substitu-
ent on a Cp or indenyl ring would easily lead to the for-
mation of a metalloxacyclic complex via the elimination
of a CH3Cl molecule at higher reaction temperature; thus
it is reasonable that in the cases of complexes 7 and
8 analogous zircoxacyclic structures might also be
formed under the adopted polymerization conditions.
Similar to complex 9, the inert intramolecular Zr―O cova-
lent bonding and the lack of two cis-located halogen
ligands might prevent the formation of any catalytically
active species. Moreover, some weak interactions
between the methoxy group and MAO might also be
the factor accounting for the deactivation of these
zirconocene complexes.
L1H2: R1 = H, R2 = R3 = Me
L2H2: R1 = H, R2 = Me, R3
L3H2: R1 = H, R2 = R3 = Et
=
nPr
1) 2 equiv. nBuLi/Et2O
2) ZrCl4
L4H2: R1 = Me, R2 = R3 = Me
L5H2: R1 = Me, R2 = Me, R3
L6H2: R1 = Me, R2 = R3 = Et
L7H2: R1 = OMe, R2 = R3 = Me
=
nPr
R1
R2
R3
L8H2: R1 = OMe, R2 = Me, R3
L9H2: R1 = OMe, R2 = R3 = Et
=
nPr
O
Zr
Cl
Zr
Cl
Cl
1-8
9
In order to investigate the influence of reaction time on
catalytic activity, propylene was polymerized for 30 and
60 min by using complexes 1, 2, 4 and 5 as catalysts in
the presence of MAO (Fig. 3). An obvious decrease in
dimerization activity was observed for all four complexes
with the prolongation of reaction time, indicating that the
active species of these complexes could not steadily
survive for a relative long time at high temperature.
Moreover, the monomer pressure and the Al/Zr ratio also
significantly influenced the catalytic activities of complexes
Ind 1: R1 = H, R2 = R3 = Me
Ind 2: R1 = H, R2 = Me, R3
Ind 3: R1 = H, R2 = R3 = Et
=
nPr
Ind 4: R1 = Me, R2 = R3 = Me
Ind 5: R1 = Me, R2 = Me, R3
Ind 6: R1 = Me, R2 = R3 = Et
=
nPr
Ind 7: R1 = OMe, R2 = R3 = Me
Ind 8: R1 = OMe, R2 = Me, R3
Ind 9: R1 = OMe, R2 = R3 = Et
=
nPr
Scheme 1. Synthesis of complexes 1–9.
Appl. Organometal. Chem. 2014, 28, 413–422
Copyright © 2014 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/aoc

W. Huang et al.
Figure 2. GC trace of propylene dimer made by complex 4/MAO (run 9).
Figure 1. ORTEP view of the molecular structure of complex 4; hydrogen
atoms have been omitted. Selected bond lengths (Å): Zr―C1 = 2.427(2),
Zr―C2= 2.559(2), Zr―C7 = 2.700(2), Zr―C8= 2.701(2), Zr―C13= 2.580(2).
Table 1. Dimerization of propylene by complexes 1–9/MAOa
Run Cat. PPE Time Yieldb
Activityc
104 g
Selectivity (%)d
(bar) (min) (mg)
(mol-Zr · h)À1
2-Methyl- 4-Methyl-
1-pentene 2-pentene
1
1
2
3
6
3
6
6
3
6
6
6
3
6
6
30
30
30
30
30
30
30
60
30
30
30
30
13.0
24.1
20.8
37.2
Trace
26.5
44.1
65.5
49.3
12.5
31.1
Trace
2.08
3.86
3.33
5.95
—
96.9
96.7
96.6
97.6
—
3.1
3.3
3.4
2.4
—
2
3
4
5
3
4
Figure 3. Influence of dimerization time on activity (polymerization condi-
tions: V= 25 ml, [Cat.]= 0.05 mmollÀ1, Al/Zr = 4000, 6 bar propylene, 100°C).
6
4.24
7.06
5.24
7.89
2.00
4.98
—
97.7
97.3
95.7
97.6
97.6
98.4
—
2.3
2.7
4.3
2.4
2.4
1.6
—
7
8
9 e
10
11
12
Previously, it was reported that ansa-zirconocene complexes
with a steric bulky substituent at the 3-position of indenyl or
cyclopentadienyl ring, such as {C2H4―1-[9-C13H8] ―2-[1-(3-tBu)
C9H5]}ZrCl2,18c {Me2C― [3-(2-CH3―2-adamantyl)C5H3] (C13H8)}
ZrCl2,18e could polymerize propylene to high-molecular-weight
polymers. Thus it is conceivable that the steric bulkiness of the
substituent at the 3-position of the indenyl ring in complexes 1,
2, 4 and 5 might not be the key factor governing the dimeriza-
tion activity and selectivity. A similar type of substituents was
used to obtain half-sandwich titanium complexes, represented
by [(C6H5)C(CH3)2(C5H4)]TiCl3, which proved to be highly
selective for ethylene trimerization.[21,22] Based on an extensive
NMR spectroscopic and DFT (density functional theory) study,
Hessen et al.[21] suggested that a hemilabile coordination effect
of the pendant aryl group to the titanium center was responsi-
ble for the trimerization selectivity, and the alkyl groups on
the quaternary carbon bridge exerted a crucial influence on
the intensity of this hemilabile interaction. Moreover, Green
et al.[23] proved that a coordination effect (more possibly, an
agostic effect) between the pendant phenyl ring and the metal
center does exist in the cationic species generated from a
5
6
aConditions: V = 25ml, [Cat.]= 0.05mmollÀ1, Al/Zr = 4000, 30 min, 100°C.
bMeasured by GC, the total mass of dimeric products.
cCatalytic activity based on all dimeric products.
dPercentage in all oligomeric products.
eAl/Zr = 8000.
1, 2, 4 and 5. With the increase of propylene pressure, the activities
of these four complexes were nearly doubled. Increasing the Al/Zr
ratio to 8000, the activity of these complexes also increased. How-
ever, as depicted in Figs 4–6, the monomer pressure, polymeriza-
tion time and Al/Zr ratio had a negligible effect on the selectivity
of complexes 1, 2, 4 and 5 towards propylene dimerization, and
high selectivities were obtained in all cases. Noticeably, for all of
these zirconocenes, no observable product including 2-methyl-1-
pentene could be detected when the polymerization temperature
was lower than 100°C.
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Copyright © 2014 John Wiley & Sons, Ltd.
Appl. Organometal. Chem. 2014, 28, 413–422

Propylene dimerization catalyzed by zirconocene complexes
1,2-insertion
[Zr]
H
Zr
β-H elimination
1,2-insertion
Zr
Scheme 2. Formation of 2-methyl-1-pentene.
16-electron zirconocene complex. All these encourage us to
suspect that a similar interaction caused the dimerization of
propylene rather than polymerization in this work.
Consistent with this assumption, the introduction of a pendant
phenyl group in complex 1 led to a highly selective catalyst for
propylene dimerization, while {C2H4―1-[9-C13H8] ―2-[1-(3-tBu)
t
C9H5]}ZrCl2 with a Bu substituent instead of a cumyl group at
Figure 4. Influence of dimerization time on selectivity (polymerization con-
ditions: V=25ml, [Cat.] =0.05mmollÀ1, Al/Zr = 4000, 6 bar propylene, 100°C).
the 3-position of indenyl ring displayed high isoselectivity and
activity for propylene polymerization.18c Furthermore, {Ph2C(9-
C13H8)[1-(3-cumyl)C5H3]}ZrCl2 bearing the same pendant substitu-
ent as complex 1 could not promote propylene polymerization.[24]
All these facts evidenced the crucial influence of the pendant aryl
group on the catalytic performance.
As suggested by Hessen et al.,[21] the alkyl substituents on the
quaternary carbon bridge would force the pendant aryl group
too close to the metal center, facilitating the occurrence of a
hemilabile interaction in the active species. The easy formation
of the zircoxacyclic complex 9 with two ethyl groups on the car-
bon bridge evidenced such a tendency. The negligible activity of
complexes 3 and 6 also indicated that the bulkier ethyl groups
might make the pendant phenyl ring get much closer to the
metal center than the others, which might disturb the coordination
of propylene monomer to the active sites. At the present stage,
although a hemilabile interaction is still uncertain, the steric
hindrance caused by a favorable orientation of the pendant aryl
group might be tentatively suggested to be responsible for the
dimerization selectivity: after two sequential monomer insertions,
the repulsion between the growing chain and surroundings might
lead to a chain termination exclusively and thus avoid the forma-
tion of trimers and any other longer-chain products. The over-
whelming 2-methyl-1-pentene fraction demonstrated that two
successive 1,2-insertions followed by a β-hydrogen elimination
constituted the dominant pathway in propylene dimerization
catalyzed by these complexes and MAO (Scheme 2).[13]
Figure 5. Influence of Al/Zr ratio on selectivity (polymerization condi-
tions: V = 25 ml, [Cat.] = 0.05 mmol lÀ1, 6 bar propylene, 30 min, 100°C).
Conclusions
In summary, a series of C1-symmetric zirconocene complexes
with a pendant aryl group on the indenyl ring were synthesized.
Among them, complexes 1, 2, 4 and 5 with less steric bulky sub-
stituents on the carbon bridge could serve as efficient catalysts
for propylene dimerization to produce 2-methyl-1-pentene in
high selectivity and moderate activity. The steric hindrance
around the metal center caused by the adjacency of the pendant
aryl group and a possible electronic interaction between this aryl
group and the metal center were both supposed to be the factors
accounting for propylene dimerization. Our subsequent work will
try to develop a comprehensive understanding of the dimeriza-
tion mechanism operating in these systems.
Figure 6. Influence of propylene pressure on selectivity (polymerization
conditions: V = 25 ml, [Cat.] = 0.05 mmol lÀ1, Al/Zr = 4000, 6 bar propylene,
100°C).
Appl. Organometal. Chem. 2014, 28, 413–422
Copyright © 2014 John Wiley & Sons, Ltd.
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W. Huang et al.
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Financial support from the National Natural Science Foundation
of China (NNSFC, 20774027 and 21274041) and the Fundamental
Research Funds for the Central Universities (WK1214048, WD1113011)
are gratefully acknowledged.
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