New zirconocenes with 4,5,6,7-tetrahydroindene ligands. Synthesis and catalytic activity in the polymerization of ethylene and copolymerization of ethylene with hex-1-ene

Article abstract of DOI:10.1007/s11172-016-1485-x

A series of symmetric and nonsymmetric tetrahydroindenyl zirconium complexes was obtained by the reaction of ZrCl₄ or (CpTMS)ZrCl₃ with lithium salts of the corresponding tetrahydroindenes. Activated with methylalumoxane, these complexes exhibit high activity in polymerization of ethylene (up to 6.8?10⁶ g PE (mol Zr h)^–1), as well as in copolymerization of ethylene and hex-1-ene (up to 8.6?10⁶ g PE (mol Zr h)^–1).

Full text of DOI:10.1007/s11172-016-1485-x

Russian Chemical Bulletin, International Edition, Vol. 65, No. 6, pp. 1580—1585, June, 2016
1580
New zirconocenes with 4,5,6,7ꢀtetrahydroindene ligands.
Synthesis and catalytic activity in the polymerization of ethylene
and copolymerization of ethylene with hexꢀ1ꢀene
A. F. Asachenko,a A. A. Bush,a A. Yu. Smirnov,a O. S. Morozov,a P. B. Dzhevakov,a S.ꢀY. Kim,b M.ꢀS. Cho,b K.ꢀS. Lee,b
Y.ꢀH. Lee,b K.ꢀJ. Cho,b S.ꢀM. Lee,b and M. S. Nechaeva,c
aA. V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences,
29 Leninsky prosp., 119991 Moscow, Russian Federation.
Eꢀmail: m.nechaev@ips.ac.ru
bLGChem Research Park, Basic Material R&D,
104ꢀ1 Munjiꢀdong, Yuseongꢀgu Daejeon, 305ꢀ738, South Korea
cM. V. Lomonosov Moscow State University, Department of Chemistry,
Build. 3, 1 Leninskie Gory, 119991 Moscow, Russian Federation
A series of symmetric and nonsymmetric tetrahydroindenyl zirconium complexes was obꢀ
tained by the reaction of ZrCl4 or (CpTMS)ZrCl3 with lithium salts of the corresponding
tetrahydroindenes. Activated with methylalumoxane, these complexes exhibit high activity in
polymerization of ethylene (up to 6.8•106 g PE (mol Zr h)–1), as well as in copolymerization of
ethylene and hexꢀ1ꢀene (up to 8.6•106 g PE (mol Zr h)–1).
Key words: zirconocenes, 4,5,6,7ꢀtetrahydroindene, polymerization, copolymerization,
ethylene, hexꢀ1ꢀene.
In 1980, it was shown1 that zirconocene Cp2ZrCl2 acꢀ
tivated with methylalumoxane (MAO) forms a catalytic
system (Cp2ZrCl2—MAO), which exhibits considerably
higher catalytic activity than the systems based on triꢀ
methylaluminum. This gave an additional impetus to the
wider use of metallocene catalysts in polymerization of
αꢀolefins in laboratory practice and industry.2,3 The develꢀ
opers of new metalloceneꢀtype catalysts have set two goals:
1) to increase productivity of catalyst for decreasing the
cost of production of polyolefins and 2) to use them for
obtaining a series of polymers with improved physical
properties (such as recyclability, mechanical and optical
properties) through a fine control of molecular weight
(Mw), molecular weight distribution (MWD), incorporaꢀ
tion degree, and statistical distribution of a comonomer in
the polymer chain, as well as a branching degree of the
polymeric chain.2,4,5
In the work,6 the authors reported the preparation of
titanium and zirconium bisꢀη5ꢀtetrahydroindenyl comꢀ
plex dichlorides in 29% (Ti) and 37% (Zr) yields by
the hydrogenation on the Adams catalyst of the correꢀ
sponding indenyl derivatives (Ind2MCl2). At the present
time, hydrogenation of indenyl precursors is the basic
method for the preparation of IV group metal tetraꢀ
hydroindenyl complexes, which are important representaꢀ
tives of catalysts of homogeneous polymerization of
olefins7,8 (Scheme 1).
Scheme 1
M = Ti, Zr
Hydrogenated metallocene complexes possess favorꢀ
able steric and electron properties, as well as are more
stables to hydrolysis.9,10 As a rule, hydrogenation of the
benzene part is the last step of the synthesis of tetraꢀ
hydroindenyl complexes. These reactions frequently give
low yields, require expensive autoclave equipment and
compliance with fire safety measures. Apart from that, it
was shown earlier that the hydrogenation of IVb group
metal metallocene dichloride complexes can result in the
formation of side products, such as hydride and lowꢀvaꢀ
lence complexes.11
Thus, the development of an alternative method for
the synthesis of tetrahydroindenyl ligands is an actual probꢀ
lem, the solution of which will make it possible to considꢀ
erably broaden the scope of synthetically available tetraꢀ
hydroindenyl metallocenes. By the present moment, only
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1580—1585, June, 2016.
1066ꢀ5285/16/6506ꢀ1580 © 2016 Springer Science+Business Media, Inc.

4,5,6,7ꢀTetrahydroindenyl zirconium catalysts
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 6, June, 2016
1581
Scheme 2
a limited amount of synthetic approaches to tetrahydroꢀ
indenyl ligands have been described.12—16
The purpose of the present work is the synthesis of new
zirconium complexes with substituted tetrahydroindenyl
ligands, bearing aryl substituents at positions 1 and 2 of
tetrahydroindene (IndH4). Such complexes cannot be obꢀ
tained in the individual state by hydrogenation because of
the low selectivity of the Adams catalyst, which gives
a mixture of products of reduction of both the indenyl fragꢀ
ment and the aromatic substituent. It should be noted that
several examples of the synthesis of symmetric 2ꢀarylꢀ
substituted tetrahydroindenyl metallocenes have been deꢀ
scribed earlier,17 but no data on the synthesis of their nonꢀ
symmetric analogues are available. This work is a continꢀ
uation of our studies on the development of metallocene
catalysts of polymerization of olefins.18—21
1, 2: Ar = Ph (a), 4ꢀMeC6H4 (b), 4ꢀMeCHC6H4 (c), 4ꢀButC6H4 (d),
4ꢀFC6H4 (e), 4ꢀMeOC6H4 (f), 2ꢀMeOC6H4 (g)
Reagents: i. 1) ArMgBr/Et2O, 2) HCl/Et2O; ii. 1) BunLi,
2) ZrCl4(THF)2.
Results and Discussion
treatment with pꢀtolyllithium with subsequent addition of
HCl in diethyl ether in 81% yield.
A synthetic approach to zirconium complexes with
substituted tetrahydroindenyl units is given in Scheme 2.
The starting 2Hꢀ3,3a,4,5,6,7ꢀhexahydroindenꢀ2ꢀone,22
2,3,4,5,6,7ꢀhexahydroindꢀ8(9)ꢀenꢀlꢀone, and 2ꢀmethylꢀ
2,3,4,5,6,7ꢀhexahydroindꢀ8(9)ꢀenꢀlꢀone23 were syntheꢀ
sized according to the procedures described in the literaꢀ
ture. 2ꢀArylꢀsubstituted ligands 1a—g were obtained in
three steps from 2Hꢀ3,3a,4,5,6,7ꢀhexahydroindenꢀ2ꢀone
(Scheme 2). Its reaction with arylmagnesium bromides
led to the corresponding allylic alcohols, which without
isolation were dehydrated under mild conditions with
a hydrogen chloride ethereal solution. Since tetrahydroꢀ
indenes 1a—g can readily undergo polymerization, to obtain
their high yields it is important to maintain the temperaꢀ
ture low and carry out the dehydration over a short time. It
is also important to note that the reaction conditions sugꢀ
gested allow one to obtain only one of possible isomeric
dienes 1a—g and avoid migration of the double bonds of
the cyclopentadiene ring. The deprotonation of tetrahydroꢀ
indenes 1a—g with a small excess of BunLi leads to the
formation of the corresponding lithium salts in a total
threeꢀstep yield from 50 to 90%. The reaction of the lithium
salts with ZrCl4•2THF in ether in the molar ratio of 2 : 1
leads to the corresponding metallocenes 2a—g in high yields.
Synthesis of 1ꢀarylꢀsubstituted tetrahydroindenes is
given in Scheme 3. 1ꢀPhenyltetrahydroindene (1h) was
obtained in two steps from 2,3,4,5,6,7ꢀhexahydroindꢀ8(9)ꢀ
enꢀlꢀone. Its treatment with phenylmagnesium bromide
leads to the corresponding allylic alcohol, which was inꢀ
volved in the second step of dehydration without additionꢀ
al purification. The dehydration was carried out for 20 min
under mild conditions with a catalytic amount of HCl in
a solution of the alcohol in diethyl ether at ~20 °C. The
target product 1h was obtained in 52% yield. 2ꢀMethylꢀ1ꢀ
tolyltetrahydroindene (1i) was obtained in one step from
2ꢀmethylꢀ2,3,4,5,6,7ꢀhexahydroindꢀ8(9)ꢀenꢀlꢀone upon
Scheme 3
1: Ar = Ph (h), 4ꢀMeC6H4 (i); R = H (h), Me (i); M = MgBr (h), Li (i)
Reagents: i. 1) ArM, 2) H+; ii. HCl, H2O.
Indenes 1b, f—i were converted to the corresponding
lithium salts by treatment with a slight excess of BunLi in
diethyl ether (Scheme 4). The reaction of the lithium salts
with (TMSC5H4)ZrCl3 (synthesized according to the proꢀ
cedure described earlier24) in toluene in the ratio of 1 : 1
gave the corresponding complexes 2h—l in high yields. All
1
the zirconocenes 2a—l were characterized by H and
13C NMR spectroscopy and elemental analysis.
The catalytic studies in the reactions of polymerizaꢀ
tion of ethylene and copolymerization of ethylene with
hexꢀ1ꢀene were carried out by the specialists of the LG
Chem company in the Research Center in Daejeon, South
Korea. As a result of these studies, an international patent
has been obtained.25 In the present work, we report the
data on the catalytic systems demonstrated the highest
activity, which were given in the patent.25
To study the influence of catalyst structure on the catꢀ
alytic activity in polymerization of ethylene and copolyꢀ

1582
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 6, June, 2016
Asachenko et al.
Scheme 4
In conclusion, we developed an efficient method for
the synthesis of 1ꢀ and 2ꢀarylꢀsubstituted tetrahydroinꢀ
denes (1a—i) and their symmetric (2a—g) and nonsymꢀ
metric (2h—l) complexes with zirconium. Complexes 2h—k
exhibit high catalytic activity in polymerization of ethylꢀ
ene (6.8•106 g PE (mol zirconocene h)–1 for the system
2i—MAO and 2k—MAO), as well as in the copolymerization
reaction of ethylene with hexꢀ1ꢀene (8.6•106 g copolyꢀ
mer (mol zirconocene h)–1 for the system 2i—MAO).
Reagents: i. 1) BunLi, 2) (TMSC5H4)ZrCl3.
Experimental
Compound
2h
2i
2j
2k
2l
R1
H
Me
R2
Ph
All the manipulations were carried out under pure argon
using standard Schlenk technique. Tetrahydrofuran, hexane, and
toluene were distilled over the system sodium—benzophenone.
Dichloromethane was distilled over calcium hydride. Aryl bromides,
dicyclopentadiene, a solution of BunLi, chlorotrimethylsilane,
a solution of hydrogen chloride in diethyl ether, and zirconium(IV)
salts were purchased from Aldrich, Fluka, ABCR, Merck, and
4ꢀMeC6H4
4ꢀMeC6H4
4ꢀMeOC6H4
2ꢀMeOC6H4
H
H
H
merization of ethylene and hexꢀ1ꢀene, we carried out
a series of catalytic experiments (Table 1). Based on the
given data, a conclusion can be drawn that the size of the
substituent at position 2 of tetrahydroindenyl ligand conꢀ
siderably affect the value of the weight average molecular
mass of a polymer obtained. As the size of substituents
increases in the order H (2h) < methyl (2i) < pꢀtolyl (2j) ≈
≈ 4ꢀmethoxyphenyl (2k), the weight average molecular
mass (Mw) decreases from 71000 to 30000. It should also
be noted that the introduction of a substituent at position
2 of tetrahydroindenyl ligand leads to a considerable deꢀ
crease in the MWD (molecular weight distribution). Thus,
the polymers obtained on the unsubstituted catalyst 2h
(entries 1 and 5) are characterized by about twice as high
values of MWD than the polymers synthesized using
2ꢀarylꢀsubstituted zirconocenes 2j and 2k (entries 3, 4, 7,
and 8). A comparison of the results of entries 1—4 and 5—8
also shows that the addition into the polymerization mixꢀ
ture of hexꢀ1ꢀene increases activity of the catalysts 2h, 2i,
and 2k. In this case, a decrease in the weight average
molecular mass of polymers (Mw) and an increase in the
MWD are observed. Conversely, in the case of catalyst 2j
the introduction of hexꢀ1ꢀene leads to the decrease in
activity, weight average molecular mass of the polymer,
and molecular weight distribution.
1
Acros and used without additional purification. H (400 MHz)
and 13C NMR spectra (100 MHz) were recorded on an AVANCE
400 spectrometer in a solution in CDCl3. Elemental analysis was
carried out using a Carlo Erba E1108 CHNCꢀO analyzer.
Synthesis of arylmagnesium bromides (general procedure).
Magnesium (2.4 g, 0.1 mol) was placed into a twoꢀneckel flask
(250 mL) equipped with a reflux condenser and anhydrous diꢀ
ethyl ether (100 mL) was added. Without stirring, a small amount
(~10%) of aryl bromide and 1,2ꢀdibromoethane (0.2 mL) for
activation of magnesium were added to the solution. After beꢀ
ginning of the reaction, the solution was stirred and the rest of
aryl bromide (a total of 0.1 mol in diethyl ether (20 mL)) was
added over 30 min, then the reaction mixture was refluxed for
2 h. After cooling the mixture to ~20 °C, the solution was transꢀ
ferred into another flask, followed by the addition of diethyl
ether to a total volume of 150 mL. The concentration of Grigꢀ
nard reagents was determined by titration. This procedure was
used to obtain phenylmagnesium bromide, pꢀtolylmagnesium
bromide, 4ꢀisopropylphenylmagnesium bromide, 4ꢀtertꢀbuꢀ
tylphenylmagnesium bromide, 4ꢀfluorophenylmagnesium broꢀ
mide, 4ꢀmethoxyphenylmagnesium bromide, 2ꢀmethoxyphenylꢀ
magnesium bromide.
Synthesis of 2ꢀaryltetrahydroindenes (general procedure).
A solution of arylmagnesium bromide (1 equiv.) was added dropꢀ
wise to a solution of 4,5,6,7ꢀtetrahydroindenꢀ2ꢀone (10 g, 0.074 mol)
in anhydrous diethyl ether (100 mL) cooled to –20 °C over
20 min. Then, the cooling bath was removed and the mixture was
Table 1. Results of catalytic tests of zirconocenes
Entries
Monomers
Metallocene
Activity
Mw/g mol–1
MWD
/kg PE (mmol zirconocene h)–1
1
2
3
4
5
6
7
8
C2H4
C2H4
C2H4
2h
2i
2j
2k
2h
2i
4.5
6.8
6.3
6.8
6.3
8.6
6.0
7.7
71000
53000
30000
34000
47000
26000
17000
14000
18.5
14.2
14.7
14.4
10.3
17.6
14.0
15.6
C2H4
C2H4+C6H12
C2H4+C6H12
C2H4+C6H12
C2H4+C6H12
2j
2k

4,5,6,7ꢀTetrahydroindenyl zirconium catalysts
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 6, June, 2016
1583
stirred for 8 h. After this, the reaction mixture was cooled to –10 °C,
followed by the addition of a 2.0 M solution of hydrogen chloride
(41 mL, 1.11 equiv.) in diethyl ether. After 15 min, the mixture
was poured into water (200 mL), the organic layer was sepꢀ
arated, whereas the aqueous layer was extracted with diethyl
ether. The combined organic fractions were dried with sodium
sulfate. The solvent was removed at reduced pressure. The product
was purified by column chromatography on silica gel (eluent
nꢀhexane).
2ꢀPhenylꢀ4,5,6,7ꢀtetrahydroindene (1a). A white crystalline
compound, the yield was 9.2 g (64%). 1H NMR (CDCl3),
δ: 1.67—1.78 (m, 4 H); 2.25—2.33 (m, 2 H); 2.33—2.42 (m, 2 H);
3.24 (s, 2 H); 6.66 (s, 1 H); 7.14 (t, 1 H, J = 7.32 Hz); 7.28 (t, 2 H,
J = 7.69 Hz); 7.45 (d, 2 H, J = 8.30 Hz). 13C NMR (CDCl3), δ:
23.03, 23.22, 24.39, 25.47, 43.14, 124.57, 125.98, 128.45, 129.47,
136.62, 138.88, 139.20, 143.14. Found (%): C, 91.96; H, 8.04.
C15H16. Calculated (%): C, 91.78; H, 8.22.
J = 1.22 Hz); 7.04 (d, 1 H, J = 8.30 Hz); 7.19 (dt, 2 H, J = 7.53 Hz,
J = 5.77 Hz, J = 1.83 Hz); 7.49 (t, 1 H, J = 7.72 Hz). 13C NMR
(CDCl3), δ: 21.70, 21.90, 23.58, 23.76, 49.82, 54.67, 110.61,
115.19, 120.29, 127.88, 128.36, 130.38, 130.79, 133.37, 143.78,
155.18. Found (%): C, 84.84; H, 8.09. C16H18O. Calculated (%):
C, 84.91; H, 8.02.
1ꢀPhenylꢀ4,5,6,7ꢀtetrahydroindene (1h) was obtained accordꢀ
ing to the general procedure from 4,5,6,7ꢀtetrahydroindenꢀ1ꢀ
one, the yield was 5.6 g (52%). 1H NMR (CDCl3), δ: 1.62—1.74
(m, 4 H); 2.54—2.62 (m, 2 H); 2.62—2.67 (m, 2 H); 2.79—2.86
(m, 2 H); 5.60 (w.sh, 1 H); 7.24 (t, 1 H, J = 7.23 Hz); 7.36 (t, 2 H,
J = 7.81 Hz); 7.41 (d, 2 H, J = 8.14 Hz). 13C NMR (CDCl3), δ:
22.80, 25.12, 25.64, 27.26, 33.29, 116.58, 126.50, 127.42, 128.14,
137.04, 137.95, 138.22, 147.16. Found (%): C, 91.74; H, 8.26.
C15H16. Calculated (%): C, 91.78; H, 8.22.
2ꢀMethylꢀ1ꢀ(pꢀtolyl)ꢀ4,5,6,7ꢀtetrahydroindene (1i). A soluꢀ
tion of BunLi (13.3 mL, 2.5 M) was added to a solution of
4ꢀbromotoluene (5.69 g, 0.033 mol) in anhydrous THF cooled
to –80 °C at such a rate that to keep the temperature of the
reaction mixture below –60 °C. The reaction mixture was stirred
for another 1 h at –80 °C, followed by the addition of 2ꢀmethylꢀ
4,5,6,7ꢀtetrahydroindanꢀ1ꢀone, the cooling bath was removed.
When the mixture warmedꢀup to ~20 °C, it was diluted by
a solution of hydrochloric acid (2 mL, 2.0 M). THF was evaporatꢀ
ed at reduced pressure, dichloromethane (100 mL) was added to
the residue. The organic layer was separated, whereas the aqueous
layer was extracted twice with dichloromethane. The combined
organic layer was dried with Na2SO4, the solvent was removed on
a rotary evaporator. The product was isolated using column chroꢀ
matography on silica gel (eluent dichloromethane). The yield
was 6 g (81%) of pure compound obtained as pale yellow crystals.
1H NMR (CDCl3), δ: 1.5 (d, 1 H); 1.55 (d, 1 H); 1.79 (d, 2 H);
2.02 (s, 3 H); 2.17 (d, 4 H); 2.39 (d, 3 H); 3.34 (s, 1 H); 5.54 (s, 1 H);
7.14—7.29 (m, 4 H). 13C NMR (CDCl3), δ: 20.42, 20.79, 22.35,
24.83, 36.29, 38.87, 115.57, 127.54, 128.27, 128.38, 128.49,
135.58, 142.51, 145.22. Found (%): C, 91.09; H, 8.91. C17H20.
Calculated (%): C, 91.01; H, 8.99.
Bis(2ꢀarylꢀ4,5,6,7ꢀtetrahydroindenyl)zirconium dichlorides
(general procedure). Butyllithium (5.2 mL, 2.5 M solution in
hexane) was added dropwise to a solution of 2ꢀarylꢀ4,5,6,7ꢀtetraꢀ
hydroindene (13 mmol) in anhydrous diethyl ether (70 mL) at
–20 °C. The solution was warmedꢀup to ~20 °C and stirred overꢀ
night. The reagent ZrCl4(THF)2 (4.4 g, 12 mmol) was added to
the lithium salt obtained, the mixture was stirred for 8 h. The
solvents were evaporated at reduced pressure, the residue was
diluted with anhydrous toluene (50 mL) and the mixture was
heated to 80—90 °C. The resulting mixture was filtered through
celite, the filtrate was concentrated and diluted with anhydrous
hexane (10 mL). Then, the solution was placed into a freezer to
crystallize the product. The crystals formed were collected by
filtration, washed several times with anhydrous hexane, and dried
in vacuo (~1 Torr).
2ꢀ(pꢀTolyl)ꢀ4,5,6,7ꢀtetrahydroindene (1b). A white powder,
1
the yield was 10.3 g (66%). H NMR (CDCl3), δ: 1.04 (d, 3 H,
J = 6.85 Hz); 1.23—1.38 (m, 1 H); 1.43—1.60 (m, 1 H);
1.66—1.90 (m, 2 H); 2.09—2.27 (m, 4 H); 2.38 (s, 3 H);
3.27—3.38 (m, 1 H); 5.54 (d, 1 H, J = 2.57 Hz); 7.19 (d, 2 H,
J = 8.31 Hz); 7.23 (d, 2 H, J = 8.31 Hz). 13C NMR (CDCl3), δ:
20.42, 20.79, 22.35, 24.83, 24.85, 36.29, 38.87, 127.54, 128.38,
128.49, 135.58, 142.51, 145.22, 147.72, 153.99. Found (%):
C, 91.30; H, 8.58. C16H18. Calculated (%): C, 91.37; H, 8.63.
2ꢀ(4ꢀIsopropylphenyl)ꢀ4,5,6,7ꢀtetrahydroindene (1c). Pale
yellow crystals, the yield was 9.0 g (51%). 1H NMR (CDCl3), δ:
1.29 (d, 6 H); 1.76 (d, 4 H); 2.35 (d, 4 H); 2.92 (d, 1 H); 3.27 (s, 1 H);
6.65 (s, 1 H); 7.20 (d, 2 H); 7.42 (d, 2 H). 13C NMR (CDCl3),
δ: 22.65, 22.85, 23.55, 24.02, 25.08, 33.37, 42.79, 124.21, 126.12,
128.29, 133.96, 138.25, 138.46, 142.82, 146.32. Found (%):
C, 90.63; H, 9.27. C18H22. Calculated (%): C, 90.70; H, 9.30.
2ꢀ(4ꢀtertꢀButylphenyl)ꢀ4,5,6,7ꢀtetrahydroindene (1d). Pale
1
yellow crystals, the yield was 8.0 g (43%). H NMR (CDCl3),
δ: 1.37 (s, 9 H); 1.77 (d, 4 H); 2.37 (d, 4 H); 3.28 (br.s, 2 H); 6.66
(s, 1 H); 7.38 (d, 2 H, J = 8.56 Hz); 7.44 (d, 2 H, J = 8.56 Hz).
13C NMR (CDCl3), δ: 22.66, 22.86, 24.03, 25.10, 30.93, 34.06,
42.78, 123.96, 124.98, 128.39, 133.57, 138.29, 138.28, 142.72,
148.55. Found (%): C, 90.39; H, 9.60. C19H24. Calculated (%):
C, 90.42; H, 9.58.
2ꢀ(4ꢀFluorophenyl)ꢀ4,5,6,7ꢀtetrahydroindene (1e). A white
1
powder, the yield was 7.6 g (48%). H NMR (CDCl3), δ: 1.76
(dt, 4 H, J = 6.02 Hz, J = 2.92 Hz); 2.27—2.36 (m, 2 H); 2.36—2.43
(m, 2 H); 3.23 (d, 2 H, J = 1.10 Hz); 6.61 (s, 1 H); 6.96—7.06
(m, 2 H); 7.38—7.49 (m, 2 H). 13C NMR (CDCl3), δ: 22.62,
22.81, 23.98, 25.04, 42.86, 114.90 (d, J = 21.47); 125.53, 125.60,
128.77, 132.53 (d, J = 3.45); 138.58 (d, J = 15.34), 141.66,
161.04 (d, J = 244.98). Found (%): C, 83.97; H, 7.01. C15H15F.
Calculated (%): C, 84.08; H, 7.06.
2ꢀ(4ꢀMethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroindene (1f). A white
1
powder, the yield was 12.1 g (72%). H NMR (CDCl3), δ: 1.47
(d, 2 H); 1.86 (d, 2 H); 2.33 (d, 2 H); 2.56 (d, 2 H); 3.49 (s, 2 H);
3.82 (s, 3 H); 6.61 (s, 1 H); 6.84 (d, 2 H); 7.30 (d, 2 H). 13C NMR
(CDCl3), δ: 22.28, 22.34, 30.00, 33.56, 48.57, 55.29, 114.01,
127.41, 128.98, 131.81, 133.69, 139.67, 150.33, 159.05. Found (%):
C, 84.82; H, 8.12. C16H18O. Calculated (%): C, 84.91; H, 8.02.
2ꢀ(2ꢀMethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroindene (1g). A white
Bis(2ꢀphenylꢀ4,5,6,7ꢀtetrahydroindenyl)zirconium dichloride
(2a). A grey microcrystalline powder, the yield was 0.970 g (27%).
1H NMR (CDCl3), δ: 1.44 (d, 4 H); 1.87 (d, 4 H); 2.33 (d, 8 H);
6.24 (s, 4 H); 7.23—7.41 (m, 10 H). 13C NMR (CDCl3), δ:
21.98, 23.83, 113.63, 123.97, 125.23, 127.25, 128.92, 130.80,
133.33. Found (%): C, 64.31; H, 5.96. C30H30Cl2Zr. Calculated (%):
C, 65.19; H, 5.47.
1
powder, the yield was 15.6 g (93%). H NMR (CDCl3), δ: 1.78
(d, 2 H); 1.96 (d, 2 H); 2.19 (d, 1 H); 2.32 (d, 1 H); 2.53 (d, 2 H);
3.55 (d, 2 H); 3.87 (d, 3 H); 5.94 (d, 1 H); 6.96 (td, 1 H, J = 7.51 Hz,
Bis[2ꢀ(pꢀtolyl)ꢀ4,5,6,7ꢀtetrahydroindenyl]zirconium dichlorꢀ
ide (2b). A grey microcrystalline powder, the yield was 1.17 g

1584
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 6, June, 2016
Asachenko et al.
1
(31%). H NMR (CDCl3), δ: 1.38—1.51 (m, 4 H); 1.80—1.95
(m, 4 H); 2.23—2.34 (m, 4 H); 2.37 (s, 6 H); 2.39—2.50 (m, 4 H);
6.18 (s, 4 H); 7.16 (d, 4 H, J = 7.81 Hz); 7.27 (d, 4 H, J = 8.30 Hz).
13C NMR (CDCl3), δ: 21.18, 22.04, 22.60, 23.92, 31.54, 113.27,
124.60, 125.19, 129.51, 130.51, 130.67, 137.03. Found (%): C, 66.51;
H, 6.02. C32H36Cl2Zr. Calculated (%): C, 66.18; H, 5.90.
Bis[2ꢀ(4ꢀisopropylphenyl)ꢀ4,5,6,7ꢀtetrahydroindenyl]zirconꢀ
ium dichloride (2c). A yellow microcrystalline powder, the yield
was 1.41 g (34%). 1H NMR (CDCl3), δ: 1.26 (d, 12 H, J = 6.91 Hz);
1.36—1.45 (m, 4 H); 1.78—1.87 (m, 4 H); 2.17—2.24 (m, 4 H);
2.24—2.32 (m, 4 H); 2.92 (septet, 2 H, J = 6.92 Hz); 6.26 (s, 4 H);
7.24 (d, 4 H, J = 8.22 Hz); 7.36 (d, 4 H, J = 8.22 Hz). 13C NMR
(CDCl3), δ: 22.04, 23.68, 24.02, 33.87, 113.32, 124.00, 125.30,
126.94, 130.49, 130.73, 148.27. Found (%): C, 67.97; H, 6.81.
C36H42Cl2Zr. Calculated (%): C, 67.89; H, 6.65.
were added. The organic layer was separated and dried with
Na2SO4, the solvent was removed at reduced pressure. The prodꢀ
uct was distilled to obtain trimethylsilylcyclopentadiene (21.4 g)
as a colorless liquid (b.p. 57—61 °C at 30 Torr). This compound
was dissolved in diethyl ether (150 mL) and BunLi (2.5 M soluꢀ
tion in hexane, 62.5 mL) was added. The mixture was stirred
over night, the solvents were removed at reduced pressure, the
residue was dissolved in THF (100 mL). The solution was cooled
to –80 °C and trimethylsilyl chloride (16.8 g, 155 mmol) was
added. The reaction mixture was allowed to warmꢀup to ~20 °C
(over about 1 h) and treated with little methanol and hydrochloric
acid, and then poured into water. The product was extracted
with hexane (3×100 mL). The combined organic layer was dried
with magnesium sulfate. The evaporation of the solvent at reꢀ
duced pressure gave the product (27.7 g, 40%) as a pale yellow
oil. The product was a mixture of isomers. It was used in subseꢀ
quent syntheses without additional purification.
Bis[2ꢀ(4ꢀtertꢀbutylphenyl)ꢀ4,5,6,7ꢀtetrahydroindenyl]zirconꢀ
ium dichloride (2d). Large yellow crystals, the yield was 1.25 g
(29%). 1H NMR (CDCl3), δ: 1.33 (s, 18 H); 1.34—1.42 (m, 4 H);
1.77—1.86 (m, 4 H); 2.14—2.27 (m, 8 H); 6.27 (s, 4 H); 7.38 (d, 4 H,
J = 8.39 Hz); 7.40 (d, 4 H, J = 8.39 Hz). 13C NMR (CDCl3),
δ: 22.01, 23.59, 31.33, 34.63, 113.32, 123.72, 125.02, 125.79, 130.25,
130.49, 150.54. Found (%): C, 69.17; H, 7.11. C38H46Cl2Zr,
Calculated (%): C, 68.64; H, 6.97.
(Trimethylsilylcyclopentadienyl)zirconium trichloride. Zirconꢀ
ium(IV) chloride (20.9 g, 90 mmol) was suspended in anhydrous
toluene (450 mL). A mixture of isomers of bis(trimethylsilyl)ꢀ
cyclopentadiene (18.9 g, 90 mmol) was added to the suspension
obtained and slowly heated to 100 °C. Then, the reaction mixꢀ
ture was stirred at this temperature overnight and filtered. The
mother liquor obtained was placed into a freezer (–30 °C). A preꢀ
cipitate formed was collected by filtration, washed with hexane,
and dried in vacuo, using an oil pump. The yield was 18.3 g (63%).
1H NMR (CDCl3), δ: 6.98 (d, 2 H); 6.94 (d, 2 H); 0.35 (s, 9 H).
(Arylꢀ4,5,6,7ꢀtetrahydroindenyl)(trimethylsilylcyclopentadiꢀ
enyl)zirconium dichlorides (general procedure). Butyllithium (2.4 mL,
2.5 M solution in hexane) was added dropwise to a solution of
arylꢀ4,5,6,7ꢀtetrahydroindene (6 mmol) in anhydrous diethyl
ether (40 mL) at –20 °C. Then, the solution was heated to ~20 °C
and stirred for 8 h. Diethyl ether was removed at reduced presꢀ
sure, toluene (40 mL) and (TMSC5H4)ZrCl3 (1.8 g, 0.9 equiv.)
were added to the residue. The reaction mixture was heated to
100 °C and stirred overnight. The resulting mixture was filtered
through celite, the filtrate was concentrated to 10 mL. The solution
obtained was placed into a freezer to crystallize the product. The
crystals formed were collected by filtration, washed with anhyꢀ
drous hexane several times and dried in vacuo, using an oil pump.
(1ꢀPhenylꢀ4,5,6,7ꢀtetrahydroindenyl)(trimethylsilylcycloꢀ
pentadienyl)zirconium dichloride (2h). A yellow microcrystalline
Bis[2ꢀ(4ꢀfluorophenyl)ꢀ4,5,6,7ꢀtetrahydroindenyl]zirconium
dichloride (2e). A pale yellow microcrystalline powder, the yield
was 1.53 g (40%). H NMR (CDCl3), δ: 1.42—1.52 (m, 4 H);
1
1.80—1.88 (m, 4 H); 2.31—2.40 (m, 4 H); 2.42—2.50 (m, 4 H);
6.20 (s, 4 H); 7.02 (t, 4 H, J = 8.59 Hz); 7.30 (dd, 4 H, J = 8.80 Hz,
J = 5.18 Hz). 13C NMR (CDCl3), δ: 22.04, 24.04, 113.03, 115.82
(d, J = 21.01 Hz); 123.68, 126.92 (d, J = 7.74 Hz); 129.46 (d, J =
= 3.21 Hz); 130.86, 162.01 (d, J = 247.68 Hz). Found (%): C, 61.44;
H, 4.85. C30H28F2Cl2Zr. Calculated (%): C, 61.21; H, 4.79.
Bis[2ꢀ(4ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroindenyl]zirconꢀ
ium dichloride (2f). Bright yellow crystals, the yield was 1.87 g
1
(47%). H NMR (CDCl3), δ: 1.46 (d, 4 H); 1.85 (d, 4 H); 2.33
(d, 4 H); 2.45 (d, 4 H); 3.83 (s, 6 H); 6.16 (s, 4 H); 6.88 (d, 4 H);
7.30 (d, 4 H). 13C NMR (CDCl3), δ: 22.08, 23.97, 55.30, 112.59,
114.18, 124.85, 126.15, 126.56, 130.29, 158.92. Found (%): C, 62.99;
H, 5.77. C32H34Cl2O2Zr. Calculated (%): C, 62.73; H, 5.59.
Bis[2ꢀ(2ꢀmethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroindenyl]zirconꢀ
ium dichloride (2g). A yellow microcrystalline powder, the yield
1
was 1.71 g (43%). H NMR (CDCl3), δ: 1.45—1.59 (m, 4 H);
1
1.96—2.11 (m, 4 H); 2.32—2.44 (m, 4 H); 2.55—2.70 (m, 4 H);
3.92 (s, 6 H); 6.27 (s, 4 H); 6.95 (td, 2 H, J = 7.52 Hz, J = 1.22 Hz);
7.00 (d, 2 H, J = 8.31 Hz); 7.18 (dt, 2 H, J = 7.58 Hz, J = 5.78 Hz,
J = 1.83 Hz); 7.29 (t, 2 H, J = 7.76 Hz). 13C NMR (CDCl3), δ:
21.70, 23.58, 54.67, 110.61, 115.19, 115.34, 120.29, 121.27,
122.43, 127.88, 128.36, 130.38, 155.18. Found (%): C, 62.90;
H, 5.83. C32H34Cl2O2Zr. Calculated (%): C, 62.73; H, 5.59.
Bis(trimethylsilyl)cyclopentadiene. Cyclopentadiene dimer
was decomposed at 160 °C. Butyllithium (2.5 M solution in hexꢀ
ane, 121 mL, 303 mmol,) and diethyl ether (100 mL) were placed
into a 1ꢀL flask. The solution was cooled to –5 °C, followed by
a dropwise addition of cyclopentadiene (20 g, 303 mmol) and
stirring for 18 h. All the volatile compounds were removed at
reduced pressure. The residue was washed thrice with diethyl
ether and dried in vacuo, using an oil pump. The yield of cycloꢀ
pentadiene lithium salt was 21.3 g (293 mmol). This salt was
dissolved in THF (150 mL), and trimethylsilyl chloride (50 mL)
was slowly added at 0 °C. The reaction mixture was stirred overꢀ
night at ~20 °C, then water (100 mL) and diethyl ether (200 mL)
powder, the yield was 1.28 g (43%). H NMR (CDCl3), δ: 0.25
(s, 9 H); 1.42—1.58 (m, 1 H); 1.63—1.74 (m, 2 H); 1.93—2.03
(m, 1 H); 2.44—2.59 (m, 2 H); 2.92—3.03 (m, 1 H); 3.10—3.23
(m, 1 H); 5.73 (d, 1 H, J = 3.29 Hz); 5.87—5.96 (m, 1 H); 6.06—6.15
(m, 1 H); 6.35—6.41 (m, 1 H); 6.41—6.44 (m, 1 H); 6.72 (d, 1
H, J = 3.29 Hz); 7.27 (t, 1 H, J = 7.24 Hz); 7.31 (d, 2 H, J = 7.65 Hz);
7.38 (t, 2 H, J = 7.48 Hz). 13C NMR (CDCl3), δ: 0.00, 21.39,
22.75, 24.62, 25.18, 108.18, 110.87, 113.35, 119.15, 121.65,
124.53, 125.52, 127.43, 127.62, 128.78, 132.06, 134.04. Found (%):
C, 56.00; H, 5.84. C23H28Cl2SiZr. Calculated (%): C, 55.84; H, 5.71.
[2ꢀMethylꢀ1ꢀ(pꢀtolyl)ꢀ4,5,6,7ꢀtetrahydroindenyl](trimethylꢀ
silylcyclopentadienyl)zirconium dichloride (2i). A yellow microꢀ
crystalline powder, the yield was 0.75 g (24%). 1H NMR
(CDCl3), δ: 0.26 (s, 9 H); 1.37—1.51 (m, 1 H); 1.51—1.58 (m, 1 H);
1.58—1.67 (m, 1 H); 1.69—1.80 (m, 1 H); 2.20 (s, 3 H); 2.22—2.26
(m, 1 H); 2.31 (s, 3 H); 2.47—2.59 (m, 1 H); 2.60—2.68 (m, 1 H);
2.93—3.05 (m, 1 H); 5.94 (br.s, 1 H); 6.06—6.10 (m, 1 H);
6.21—6.25 (m, 1 H); 6.46—6.50 (m, 2 H); 7.11 (d, 2 H, J = 8.14 Hz);
7.14 (d, 2 H, J = 8.14 Hz). 13C NMR (CDCl3), δ: 0.19, 16.72,

4,5,6,7ꢀTetrahydroindenyl zirconium catalysts
Russ.Chem.Bull., Int.Ed., Vol. 65, No. 6, June, 2016
1585
21.41, 22.67, 23.24, 25.01, 25.95, 111.37, 115.06, 116.27, 124.25,
125.67, 126.12, 126.23, 129.27, 130.43, 131.49, 135.30, 137.33.
Found (%): C, 57.59; H, 6.23. C25H32Cl2SiZr. Calculated (%):
C, 57.44; H, 6.17.
References
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[2ꢀ(pꢀTolyl)ꢀ4,5,6,7ꢀtetrahydroindenyl](trimethylsilylcycloꢀ
pentadienyl)zirconium dichloride (2j). A yellow microcrystalline
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1
powder, the yield was 1.37 g (45%). H NMR (CDCl3), δ: 0.17
(s, 9 H); 1.48—1.59 (m, 2 H); 1.83—1.94 (m, 2 H); 2.32 (s, 3 H);
2.46—2.58 (m, 2 H); 2.72— 2.84 (m, 2 H); 5.94 (t, 2 H, J = 2.43 Hz);
6.23 (br.s, 2 H); 6.32 (t, 2 H, J = 2.47 Hz); 7.18 (d, 2 H, J = 8.14 Hz);
7.37 (d, 2 H, J = 8.14 Hz). 13C NMR (CDCl3), δ: –0.09, 21.21,
22.08, 24.60, 108.73, 117.62, 124.89, 125.17, 126.17, 128.32,
129.78, 131.12, 132.56, 137.68. Found (%): C, 56.95; H, 6.01.
C24H30Cl2SiZr. Calculated (%): C, 56.66; H, 5.94.
[2ꢀ(4ꢀMethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroindenyl](trimethylꢀ
silylcyclopentadienyl)zirconium dichloride (2k). A yellow microꢀ
crystalline powder, the yield was 1.61 g (51%). 1H NMR (CDCl3),
δ: 0.27 (s, 9 H); 1.63 (d, 2 H); 2.02 (d, 2 H); 2.63 (d, 2 H); 2.89
(d, 2 H); 4.00 (s, 3 H); 6.03 (d, 2 H); 6.41 (d, 2 H); 6.54 (d, 1 H);
7.08 (d, 2 H); 7.33 (d, 2 H); 7.58 (d, 1 H). 13C NMR (CDCl3), δ:
0.50, 21.72, 24.14, 54.72, 111.02, 111.34, 117.30, 120.77, 122.64,
124.62, 127.34, 128.46, 132.21, 155.27. Found (%): C, 62.99;
H, 5.77. C32H34Cl2O2Zr. Calculated (%): C, 62.73; H, 5.59.
Found (%): C, 55.31; H, 5.88. C24H30Cl2OSiZr. Calculated (%):
C, 54.94; H, 5.76.
[2ꢀ(2ꢀMethoxyphenyl)ꢀ4,5,6,7ꢀtetrahydroindenyl](trimethylꢀ
silylcyclopentadienyl)zirconium dichloride (2l). A yellow microꢀ
crystalline powder, the yield was 1.51 g (48%). 1H NMR
(CDCl3), δ: 0.27 (s, 9 H); 1.56—1.73 (m, 2 H); 1.94—2.10 (m, 2 H);
2.57—2.68 (m, 2 H); 2.85—2.97 (m, 2 H); 4.00 (s, 3 H); 6.03 (t, 2 H,
J = 2.45 Hz); 6.41 (t, 2 H, J = 2.45 Hz); 6.54 (s, 2 H); 7.07
(td, 1 H, J = 5.01 Hz, J = 4.16 Hz, J = 1.10 Hz); 7.10 (dd,
J = 7.46 Hz, J = 1.10 Hz); 7.33 (td, 1 H, J = 7.90 Hz, J = 7.46 Hz,
J = 1.59 Hz); 7.58 (dd, J = 7.70 Hz, J = 1.59 Hz). 13C NMR
(CDCl3), δ: –0.50, 21.72, 24.14, 54.72, 111.02, 111.34, 117.30,
120.77, 122.64, 123.13, 124.62, 127.15, 127.34, 128.46, 132.21,
155.27. Found (%): C, 55.40; H, 5.84. C24H30Cl2OSiZr. Calcuꢀ
lated (%): C, 54.94; H, 5.76.
Polymerization (general procedure). A 300ꢀmL flask was
washed with a small amount of a solution of AlMe3 in toluene,
then toluene (180 mL) and MAO (5 mL, 10 wt.%) were placed
into this flask. The flask was equipped with a mechanical stirrer
and placed in an oil bath heated to 90 °C. A metallocene catalyst
(20 μmol) was dissolved in toluene (20 mL) in a separate flask.
To carry out the polymerization, this solution (5 mL) was added
to the mixture. Ethylene was passed through the content of the
flask until saturation of the solution, the operation was repeated
three times. The polymerization was carried out with stirring
(500 rpm) for 30 min. Upon completion of the reaction, the
mixture was cooled to ~20 °C, the content of the flask was poured
into ethanol (400 mL) and this mixture was stirred for 1 h. The
polymer was collected by filtration and dried in a vacuum oven
for 20 h at 60 °C. A small amount of the sample was analyzed by
gelꢀpermeation chromatography.
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25 WO Pat. 2014061921ꢀA1, 2014.
Copolymerization of ethylene and hexꢀ1ꢀene was carried
out similarly to the procedure described above, except that hexꢀ
1ꢀene (5 mL) was added to the reaction mixture before placing it
in an oil bath.
Received March 16, 2016;
in revised form April 6, 2016