Synthesis, structure and α-olefin polymerization activity of group 4 metal complexes with [OSSO]-type bis(phenolate) ligands

Article abstract of DOI:10.1016/j.jorganchem.2011.01.021

The tetradentate [OSSO]-type bis(phenol) ligands, [{2,2′-(HOC ₆H₂-4,6-R₂)₂CH₂SCH ₂CH₂SCH₂}] (R = ^tBu, 2; Br, 3) react with MBz₄ (M = Zr, Hf) to yield the corresponding dibenzyl complexes, [M{2,2′-(OC₆H₂-4,6-R₂) ₂CH₂SCH₂CH₂SCH₂}Bz ₂] (R = Br, M = Zr, 4^Br; Hf, 5^Br; R = ^tBu, M = Hf, 5) in a good to very good yield. Zirconium diamido complexes, [Zr{2,2′-(OC₆H₂-4,6-R₂) ₂CH₂SCH₂CH₂SCH₂}(NMe ₂)₂] (R = ^tBu, 6; Br, 6^Br) were prepared in a reaction of the corresponding disodium salt of 2 or 3 generated in situ with ZrCl₂(NMe₂)₂(THF)₂. Heating of 6 with TMSCl at 35 °C afforded zirconium dichloro complex, [Zr{2,2′-(OC₆H₂-4,6-^tBu₂) ₂CH₂SCH₂CH₂SCH₂}Cl ₂] (7), whereas the titanium analog 8 was prepared in a direct reaction with TiCl₄. While for complexes 4^Br, 5, 5 ^Br, 6, 6^Br and 7 single C₂-symmetric isomers were observed in solution at room temperature, as revealed by the NMR spectroscopic data, titanium complex 8 formed as a mixture of cis-α (8a) and cis-β (8b) isomers in a ratio of approx. 20:80% (measured in CD ₂Cl₂). The VT NMR studies revealed a reversible conversion of 8a into 8b above 60 °C. The X-ray crystal structure determination of complexes 4^Br, 5^Br and 7 confirmed their C ₂-symmetrical configuration in the solid state with cis-arranged benzyl/chloro groups and the trans-coordination of two bulky phenolato moieties. The zirconium dibenzyl complexes exhibit good catalytic activities in homopolymerization of 1-hexene (atactic poly(1-hexene), PDI = 1.5-1.7) and vinylcyclohexane (isotactic poly(vinylcyclohexane), PDI = 1.2-1.8) upon activation with a co-catalyst. In both polymerizations no increase of activity was observed for the complex 4^Br with electron-withdrawing substituents on phenolate rings. Moreover, polymerization of liquid propylene catalyzed by the titanium dichloro isomeric mixture 8 afforded at 5 °C ultrahigh molecular weight atactic/isotactic polypropylene mixtures.

Full text of DOI:10.1016/j.jorganchem.2011.01.021

Journal of Organometallic Chemistry 696 (2011) 1792e1802
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis, structure and a-olefin polymerization activity of group 4 metal
complexes with [OSSO]-type bis(phenolate) ligands
,
Marcin Konkol a, Masaaki Nabika a, Tetsuya Kohno b, Takahiro Hino a, Tatsuya Miyatake a
*
a Petrochemicals Research Laboratory, Sumitomo Chemical Co., Ltd., 2-1 Kitasode, Sodegaura, Chiba 299-0295, Japan
b Genomic Science Laboratories, Dainippon Sumitomo Pharma Co., Ltd., 3-1-98 Kasugadenaka, Konohana-ku, Osaka 554-0022, Japan
a r t i c l e i n f o
a b s t r a c t
The tetradentate [OSSO]-type bis(phenol) ligands, [{2,20-(HOC6H2-4,6-R2)2CH2SCH2CH2SCH2}] (R ¼ tBu,
2; Br, 3) react with MBz4 (M ¼ Zr, Hf) to yield the corresponding dibenzyl complexes, [M{2,20-(OC6H2-4,6-
R2)2CH2SCH2CH2SCH2}Bz2] (R ¼ Br, M ¼ Zr, 4Br; Hf, 5Br; R ¼ tBu, M ¼ Hf, 5) in a good to very good yield.
Article history:
Received 11 August 2010
Received in revised form
17 January 2011
Zirconium diamido complexes, [Zr{2,20-(OC6H2-4,6-R2)2CH2SCH2CH2SCH2}(NMe2)2] (R ¼ tBu, 6; Br, 6Br
)
Accepted 18 January 2011
were prepared in a reaction of the corresponding disodium salt of 2 or 3 generated in situ with
ZrCl2(NMe2)2(THF)2. Heating of 6 with TMSCl at 35 ꢀC afforded zirconium dichloro complex, [Zr{2,20-
(OC6H2-4,6-tBu2)2CH2SCH2CH2SCH2}Cl2] (7), whereas the titanium analog 8 was prepared in a direct
reaction with TiCl4. While for complexes 4Br, 5, 5Br, 6, 6Br and 7 single C2-symmetric isomers were
observed in solution at room temperature, as revealed by the NMR spectroscopic data, titanium complex
Keywords:
Polymerization
Propylene
1-Hexene
8 formed as a mixture of cis-a (8a) and cis-b (8b) isomers in a ratio of approx. 20:80% (measured in
Vinylcyclohexane
Group 4 metal
[OSSO]-type ligand
CD2Cl2). The VT NMR studies revealed a reversible conversion of 8a into 8b above 60 ꢀC. The X-ray crystal
structure determination of complexes 4Br, 5Br and 7 confirmed their C2-symmetrical configuration in the
solid state with cis-arranged benzyl/chloro groups and the trans-coordination of two bulky phenolato
moieties. The zirconium dibenzyl complexes exhibit good catalytic activities in homopolymerization of
1-hexene (atactic poly(1-hexene), PDI ¼ 1.5e1.7) and vinylcyclohexane (isotactic poly(vinylcyclohexane),
PDI ¼ 1.2e1.8) upon activation with a co-catalyst. In both polymerizations no increase of activity was
observed for the complex 4Br with electron-withdrawing substituents on phenolate rings. Moreover,
polymerization of liquid propylene catalyzed by the titanium dichloro isomeric mixture 8 afforded at 5 ꢀC
ultrahigh molecular weight atactic/isotactic polypropylene mixtures.
Ó 2011 Elsevier B.V. All rights reserved.
1. Introduction
considerable stereoelectronic variations of the resulting pre-
catalysts. It has been demonstrated that the nature of the link
The design and development of new non-metallocene multi-
dentate ligand frameworks for transition metal-based -olefin
polymerization catalysts is of particular interest from the view-
point of better understanding of the structure-property relation-
ships and thus achieving better control over molecular weight and
stereochemistry of polymers [1,2]. In recent few years non-met-
between the phenolate moieties in tetradentate bis(phenolate)
ligands may have an influence on the ligand wrapping around
a metal center and may thus affect reactivity and stereospecificity
[7h]. The group 4 metal complexes with [OSSO]-type bis(pheno-
late) ligands possessing 1,4-dithiabutanediyl-bridge developed by
Okuda et al. have been shown to lead to interesting chemical
activities such as the controlled isospecific polymerization of
styrene [5b,e,iek,n] and nonstereospecific oligomerization of 1-
hexene [5f]. Kol et al. featured a methylene spacer between the S
donor and the arene ring, achieving higher activity in polymeri-
zation of 1-hexene than the corresponding Salan-type analog but
with no stereocontrol (atactic polymer) [5g]. In contrast, high
isoselectivity in 1-hexene polymerization has been recently
observed by Ishii et al. for the zirconium dibenzyl complex with
the related bis(phenolate) ligand bearing trans-1,2-cyclooctanediyl
backbone [5a]. Moreover, Kol et al. have demonstrated for the
a
allocene group
4 complexes of the type [MX2(ODo)2] and
[MX2(ODoDoO)] (Do ¼ heteroatom donor, ODoꢁ ¼ monoanionic,
ODoDoO2ꢁ ¼ chelating, dianionic ligand) based on hard, electro-
negative,
p-donor aryl alkoxide ligands [3] with a sulfur [4,5],
nitrogen [6,7], phosphorus [8] or oxygen [9] donor function have
been receiving particular attention, since these ligands allow
* Corresponding author.
E-mail address: miyataket1@sc.sumitomo-chem.co.jp (T. Miyatake).
0022-328X/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2011.01.021

M. Konkol et al. / Journal of Organometallic Chemistry 696 (2011) 1792e1802
1793
OH
R
S
S
Br
R
NEt3, THF
2
+
R
OH HO
R
HS
SH
R
R
R = tBu, Br
Scheme 1. Synthetic route for the ligands 2 and 3.
Salan-type/diamine bis(phenolate) complexes that incorporation
of the electron-withdrawing halo substituents on phenolate rings
increases the catalyst activity in highly isospecific polymerization
of vinylcyclohexane [7e] and in living isospecific polymerization of
1-hexene [7j].
bis(phenol), 2,20-[ethane-1,2-diylbis(sulfanediylmethylene)] bis(4,6-
dibromophenol) (3) was synthesized in an analogous manner.
Reacting 2 equiv. of 2,4-dibromo-6-(bromomethyl)phenol with 1,2-
ethanedithiol in the presence of triethylamine gave the ligand
precursor 3 in 64% yield (Scheme 1).
As a part of our investigations on group 4 metal complexes sup-
ported by bis(phenolate) ligands with S-containing linkers [4e,f], we
were interested in influence of the methylene spacer incorporated
between the phenoxy group and the sulfur atom (six-membered
chelate ring) as well as the electron-withdrawing substituents on the
phenolate ring of the [OSSO]-type ligand on polymerization activity
and stereoselectivity of group 4 metal complexes. We report here the
coordination of [OSSO]-type 1,4-dithiabutanediyl-bridged bis
(phenolate) ligands, possessing a Salan-type methylene spacer, at
tetravalent titanium, zirconium and hafnium centers and the activity
of complexes as catalyst precursors in 1-hexene, vinylcyclohexane
and propylene homopolymerization.
A reaction of the ligand precursors 2 and 3 with zirconium/
hafnium tetrabenzyl complexes at room temperature led cleanly to
the corresponding bis(phenolate) dibenzylzirconium (4/4Br) and
hafnium (5/5Br) complexes (Scheme 2).
The zirconium dibenzyl complex 4 has been previously reported
by Kol et al. [5g]. The complexes were prepared as yellow (4Br) or
off-white/beige (5/5Br) solids in a good (5, 57%) to very good yield
(4Br/5Br, 89/89%). The 1H NMR spectroscopic data of all zirconium
(4/4Br) and hafnium (5/5Br) dibenzyl complexes indicate a molec-
ular C2-symmetry at ambient temperature, which is evident from
the symmetry-related chemically equivalent phenolate rings, the
AB spin pattern for the CH2SCH2CH2SCH2 bridge and the AB
doublets for the CH2 groups of both cis-benzyl ligands.
2. Results and discussion
The complexes 4Br and 5Br were further characterized by means
of X-ray crystallography and the crystals were found to be iso-
structural. The ORTEP diagrams of 4Br and 5Br with selected bond
lengths and angles are shown in Figs. 1 and 2. The crystallographic
data for 4Br and 5Br are shown in Table 1.
2.1. Synthesis and structure of complexes
The tetradentate bis(phenol), 2,20-[ethane-1,2-diylbis(sulfane-
diylmethylene)]bis(4,6-di-tert-butylphenol) (2) was prepared
accordingtoaprocedurereported byKoletal. [5g]. TheBr-substituted
The results confirm the C2-symmetrical configuration of the
complexes in the solid state with cis-arranged benzyl (4Br
,
R
R
O
M
R = tBu, M = Zr, 4
S
S
MBz4
Bz
Bz
4Br
R = Br, M = Zr,
R = tBu, M = Hf,
5
toluene
R
5Br
R = Br, M = Hf,
O
R
R
OH
S
R
S
R
OH
R
R
O
R
S
S
NMe2
NMe2
1) NaH, THF
R = tBu, 6
R = Br,
Zr
6Br
2) ZrCl2(NMe2)2(THF)2
O
R
R
Scheme 2. Synthetic route for the complexes 4/4Br, 5/5Br and 6/6Br
.

1794
M. Konkol et al. / Journal of Organometallic Chemistry 696 (2011) 1792e1802
Fig. 2. ORTEP diagram of the molecular structure of [Hf{2,20-(OC6H2-4,6-
Br2)2CH2SCH2CH2SCH2}Bz2] (5Br). Hydrogen atoms are omitted for clarity; thermal
ellipsoids are drawn at the 50% probability level. Selected bond lengths (Å) and angles
(ꢀ): Hf1eS1 2.7714(12), Hf1eS2 2.7696(14), Hf1eO1 1.994(3), Hf1eO2 2.006(3),
Hf1eC14 2.287(7), Hf1eC21 2.293(6), Hf1eC13 2.514(5), S1eHf1eS2 73.82(4),
O1eHf1eO2 157.30(17), C14eHf1eC21 125.6(2), Hf1eC14eC13 81.3(4), Hf1eC21eC20
120.2(3), S1eHf1eC14 150.30(17), S2eHf1eC21 157.63(14).
Fig. 1. ORTEP diagram of the molecular structure of [Zr{2,20-(OC6H2-4,6-
Br2)2CH2SCH2CH2SCH2}Bz2] (4Br). Hydrogen atoms are omitted for clarity; thermal
ellipsoids are drawn at the 50% probability level. Selected bond lengths (Å) and angles
(ꢀ): Zr1eS1 2.7934(7), Zr1eS2 2.7932(6), Zr1eO1 2.028(2), Zr1eO2 2.007(2), Zr1eC7
2.307(3), Zr1eC14 2.314(3), Zr1eC6 2.516(2), S1eZr1eS2 73.60(2), O1eZr1eO2 156.35
(7), C7eZr1eC14 126.55(11), Zr1eC7eC6 80.6(2), Zr1eC14eC13 120.0(2), S1eZr1eC14
157.36(7), S2eZr1eC7 149.37(8).
114.05(19)ꢀ), the ZreS bond distances are similar (2.7934(7) and
2.7932(6) Å in 4Br vs. 2.8107(8) and 2.7682(8) Å). They are,
however, shorter than the ZreS bond lengths for the [Zr{2,20-
(OC6H2-4,6-tBu2)2CH2SCH2CH2SCH2}(OtBu)2] complex (2.8279(7)
and 2.8485(7) Å) [5g].
C7eZr1eC14 126.55(11)ꢀ; 5Br, C21eHf1eC14 125.6(2)ꢀ) and thio-
ether groups (4Br, S1eZr1eS2 73.60(2)ꢀ; 5Br, S1eHf1eS2 73.82
(4)ꢀ). The trans-coordination of two bulky phenolato moieties (4Br
,
O1eZr1eO2 156.35(7)ꢀ; 5Br, O1eHf1eO2 157.30(17)ꢀ) is enforced
by the gauche (synclinal) conformation of the sulfur atoms of the
SCH2CH2S bridge with the corresponding dihedral angles of ꢁ40.8
(3)ꢀ (4Br) and ꢁ39.1(6)ꢀ (5Br). In both structures, one of the benzyl
groups binds in a h1-mode with an MeCeC angle of ca. 120.1ꢀ,
Table 1
Summary of crystallographic data for 4Br, 5Br and 7.
Complex
4Br$CH2Cl2
5Br$CH2Cl2
7$CH2Cl2
C33H50
Cl4O2S2Zr
775.91
Empirical
formula
Mr
C31H28Br4
Cl2O2S2Zr
978.42
C31H28Br4
Cl2O2S2Hf
1065.69
whereas the second benzyl group shows a h
2-binding mode via the
ipso carbon atom (4Br, Zr1eC7eC6 80.6(2)ꢀ; 5Br, Hf1eC14eC13 81.3
(4)ꢀ) with the corresponding MeCipso bond distances of 2.516(2)
Crystal size/mm 0.20 ꢂ 0.10 ꢂ 0.10 0.10 ꢂ 0.10 ꢂ 0.05 0.20 ꢂ 0.10 ꢂ 0.10
Crystal system
a/Å
b/Å
Monoclinic
8.9386(4)
22.6139(9)
17.1700(7)
3408.6(2)
P21/c (#14)
4
Monoclinic
8.9328(4)
22.625(1)
17.1494(7)
3404.1(3)
P21/c (#14)
4
Triclinic
13.2966(3)
17.3620(4)
18.3052(4)
3761.0(2)
P-1 (#2)
4
and 2.514(5) Å, respectively. A similar
h
2-coordination mode of
a benzyl group in group 4 metal complexes was observed by Ishii
[5a], Okuda [5b] and Carpentier [6c]. In both structures 4Br and 5Br
coplanarity of the zirconacyclopropane ring, the methylene carbon
atom of the second benzyl group and the two sulfur atoms results
in pentagonal bipyramidal geometry around a heptacoordinate
metal center. This higher coordination number of the metal center
may be attributed to its electron deficiency as was postulated by
Kol et al. for the related zirconium dibenzyl complexes of [ONNO0]-
type Salan ligands [7b]. Moreover, in 4Br and 5Br a phenyl ring of the
c/Å
V/Å3
Space group
Z
Dcalc/g cmꢁ3
F(000)
1.906
2.079
1.370
1904.00
110.445
93 ꢃ 1
2032.00
139.828
93 ꢃ 1
143.7
1810.00
62.466
93 ꢃ 1
136.4
m
(CuK
T/K
max/deg
a
)/cmꢁ1
2
q
143.4
No. of reflections 53690
39238
51106
h
2-benzyl group is pointed toward the 1-benzyl group.
h
No. of obs.
No. of variables
6428
491
6062
491
13128
1106
Compared to the other reported hafnium dibenzyl complex of 1,4-
dithiabutanediyl-bridged [OSSO]-type ligand, [Hf{2,20-(OC6H2-
4,6-tBu2)2SCH2CH2S}Bz2] [5n], where two benzyl groups are
directed outwards from each other, this results in an increase of the
CeHfeC bond angle in 5Br (125.6(2)ꢀ vs. 94.3(1)ꢀ) and in shorter
HfeS bond distances (2.7714(12) and 2.7696(14) Å in 5Br vs. 2.9222
(9) and 2.8260(8) Å). In the case of 4Br, although the CeZreC bond
angle is increased compared to the zirconium dibenzyl co-
mplex of 1,4-dithia-trans-1,2-cyclooctanediyl-bridged complex, [Zr
{2,20-(OC6H2-4,6-tBu2)2CH2S(Cyoct)SCH2}Bz2] [5a] (126.55(11)ꢀ vs.
Refls./Parameter 13.09
ratio
12.35
11.87
Residuals: R1
(I > 2 (I))
Residuals: R
(all data)
Residuals: wR2
(all data)
0.0260
0.0309
0.0733
0.0334
0.0432
0.0442
0.0517
0.0598
0.0874
s
GOF
1.014
1.017
1.56/-1.16
1.003
4.26/-1.93
Max/min
1.64/-0.77
peak/eꢁ Åꢁ3

tBu
tBu
1) NaH, THF
2) ZrCl2(NMe2)2(THF)2
3) TMSCl, toluene
O
S
S
Cl
Cl
Zr
tBu
O
tBu
tBu
OH
S
S
tBu
tBu
7
tBu
OH
tBu
tBu
tBu
S
Ti
O
O
Ti
O
S
tBu
S
S
TiCl4, toluene
Cl
Cl
Cl
Cl
+
O
tBu
tBu
tBu
tBu
8b
8a
Scheme 3. Synthetic route for the complexes 7 and 8a/8b.
Two bis(phenolate) zirconium diamido complexes 6 and 6Br
could be accessed in a moderate (6Br, 59%) to good (6, 73%) yield by
reacting the corresponding disodium salt of 2 or 3 generated in situ
with ZrCl2(NMe2)2(THF)2 (Scheme 2). The 1H NMR spectrum of 6
shows at room temperature
a configurationally stable C2-
symmetric structure with two aromatic doublets, four pseudo-AB
doublets for the protons of the CH2SCH2CH2SCH2 bridge and
a singlet resonance at d 3.39 ppm for the NMe2 group. On the other
hand, the 1H NMR spectrum of the analogous complex 6Br with Br-
substituted phenolate rings displays a pattern of broad signals at
room temperature, suggesting a fluxional structure. Heating of 6
with TMSCl at 35 ꢀC afforded zirconium dichloro complex 7 as
a white solid in 68% yield (Scheme 3). In contrast, the analogous
reaction of 6Br with TMSCl was not clean and the corresponding
dichloro complex was not isolated. Presumably, a Cl/Br exchange
occurred. Similarly to zirconium dibenzyl and diamido complexes,
the complex 7 has a C2-symmetric structure in solution as revealed
by the NMR spectroscopic data.
The structure of 7 was unambiguously determined by X-ray
crystallography. The ORTEP diagram of 7 with selected bond
lengths and angles is shown in Fig. 3. The crystallographic data for 7
are shown in Table 1. The asymmetric unit contains two homochiral
molecules and two molecules of dichloromethane. The structure of
only one of the two homochiral molecules will be discussed. The
central zirconium atom adopts a distorted octahedral geometry
with chloro ligands in mutual cis position and trans-coordination of
phenolato moieties (O1eZr1eO2 159.33(12)ꢀ, Zr1eO1 1.977(3),
Zr1eO2 1.977(3) Å). The smaller steric bulkiness of the chloro
ligands compared to benzyl ligands is reflected in a decrease in the
respective bond angle from 126.55(11) (C7eZr1eC14) to 108.18(4)ꢀ
(Cl1eZr1eCl2). The decrease of this angle causes a widening of the
SeZreS angle from 73.60(2) in 4Br to 74.70(3) in 7 and subsequent
shortening of the ZreS bonds by about 0.03 Å.
Fig. 3. ORTEP diagram of the molecular structure of [Zr{2,20-(OC6H2-
4,6-tBu2)2CH2SCH2CH2 SCH2}Cl2] (7). One of two molecules in the asymmetric unit is
shown. Hydrogen atoms are omitted for clarity; thermal ellipsoids are drawn at the
50% probability level. Selected bond lengths (Å) and angles (ꢀ): Zr1eS3 2.7613(9),
Zr1eS4 2.7591(11), Zr1eO1 1.977(3), Zr1eO2 1.977(3), Zr1eCl1 2.4133(11), Zr1eCl2
2.4034(9), S3eZr1eS4 74.70(3), O1eZr1eO2 159.33(12), Cl1eZr1eCl2 108.18(4),
S4eZr1eCl1 163.29(3), S3eZr1eCl2 162.42(3).
In contrast with zirconium, reaction of 2 with TiCl4 at room tem-
perature afforded the titanium dichloro complex as a mixture of cis-
a
(C2-symmetry, trans(O,O)-cis(S,S)) isomer 8a and cis-b (C1-symmetry,

1796
M. Konkol et al. / Journal of Organometallic Chemistry 696 (2011) 1792e1802
Table 2
Table 3
Polymerization of 1-hexene catalyzed by zirconium complexes 4/4Br and hafnium
complex 5 with co-catalysts.a
Polymerization of vinylcyclohexane catalyzed by zirconium complexes 4/4Br and
hafnium complex 5 with co-catalysts.a
Co-catalystb
Activityc
Mw
Mw/Mn
Entry
Catalyst
Co-catalystb
Activityc
Mw
Mw/Mn
d
d
d
d
Entry
Catalyst
1
2
3
4
5
4
4
B(C6F5)3
MAO
B(C6F5)3
B(C6F5)3
MAO
227.3
165.2
5.2
1.5
73.6
74600
46600
102000
830
1.7
1.5
1.3
1.1
1.1
6
7
8
9
4
4
B(C6F5)3
MAO
B(C6F5)3
B(C6F5)3
MAO
5.3
60.7
1.5
1.5
11.8
167000
20000
n.d.
830
530
1.8
1.2
e
4Br
5
4Br
5
1.1
1.1
5
2040
10
5
a
a
Conditions: 20 mL glass reactor, 1-hexene (10 mL), catalyst 12.0
m
mol, poly-
Conditions: 20 mL glass reactor, toluene (5 mL), vinylcyclohexane (5 mL),
mol, polymerization time 2 h, room temperature.
B(C6F5)3 16.0 mol; PMAO 1.2 mmol.
In kg mol(cat)ꢁ1
merization time 2 h, room temperature.
catalyst 12.0 m
b
b
B(C6F5)3 16.0
m
mol; TMAO 1.2 mmol.
.
m
c
c
In kg mol(cat)ꢁ1
.
d
d
Determined by GPC with polystyrene standards.
Determined by GPC with polystyrene standards.
cis(O,O)-cis(S,S)) isomer 8b in a ratio of approx. 20:80% (measured in
CD2Cl2) (Scheme 3). The VT NMR studies revealed a reversible con-
version of 8a into 8b at 60 ꢀC. This finding stands in contrast with
a conversion of cis-b to cis-a isomer observed for the titanium dichloro
complex with the [ONNO]-type 1,4-diazabutanediyl-bridged bis
(phenolate) ligand [7a].
microstructure of the polymer was investigated by 13C NMR spec-
troscopy. The presence of six main peaks corresponding to six
different carbon atoms of the polymer chain as well as the broad-
ness and pattern of the methylene peaks indicate an atactic poly(1-
hexene) (Fig. 4).
The formation of atactic polymer is in agreement with the
observations that, in the case of zirconium bis(phenolate)
complexes, bulky phenolate substituents are necessary for stereo-
specific olefin polymerization [7j,p]. Moreover, in the case of TMAO
co-catalyst the polymer obtained shows lower molecular weight
2.2. Polymerization studies
The results of 1-hexene polymerization with zirconium dibenzyl
complexes 4/4Br and hafnium dibenzyl complex 5 are summarized in
Table 2.
than using tris(pentafluorophenyl)borane, indicating
a chain
transfer reaction to alkylaluminum compound (entry 2).
The results of vinylcyclohexane (VCH) polymerization with
zirconium dibenzyl complexes 4/4Br and hafnium dibenzyl
complex 5 are summarized in Table 3.
The polymerization runs have been performed in neat monomer
under the ambient conditions. At room temperature 4Br was found
to be insoluble in 1-hexene, forming a slurry. However, after
addition of tris(pentafluorophenyl)borane a clear solution could be
obtained after a few minutes. On the contrary to the expectations,
an introduction of the electron-withdrawing substituents on
phenolate rings did not cause an increase in catalytic activity, as it
was the case for the related diamine bis(phenolate) complexes
reported by Kol et al. [7j]. Although the activity of 4Br with Br
substituents was lower than that of 4 (227.3 vs 5.2 kg mol(cat)ꢁ1), it
Polymerization runs have been carried out in a toluene solution.
The activity of the complex 4 was found to be higher upon acti-
vation with PMAO than with B(C6F5)3 (5.3 vs 60.7 kg mol(cat)ꢁ1
,
Table 3, entry 4 and 5). Polymerization with B(C6F5)3, however,
afforded poly(vinylcyclohexane) with a higher molecular weight
(Mw ¼ 167000) and with a broader molecular weight distribution
(Mw/Mn ¼ 1.8). Similarly to homopolymerization of 1-hexene, no
increase of activity was observed for Br-substituted complex 4Br
.
afforded poly(1-hexene) with
a
higher molecular weight
Moreover, the activity even decreased from 5.3 to 1.5 kg mol(cat)ꢁ1
(Table 3, entry 6). In contrast, ultrahigh activities up to 3600 g mmol
(Mw ¼ 102000, 4Br; 74600, 4, Table 2, entry 1 and 3) and a narrower
molecular weight distribution (Mw/Mn
¼
1.3 vs 1.7). The
Fig. 4. 13C NMR spectrum of poly(1-hexene) obtained with 4Br/B(C6F5)3.

M. Konkol et al. / Journal of Organometallic Chemistry 696 (2011) 1792e1802
1797
Fig. 5. 13C NMR spectrum of poly(vinylcyclohexane) obtained with 4/B(C6F5)3.
(cat)ꢁ1 hꢁ1 in isospecific vinylcyclohexane polymerization were
observed for the halo-substituted [ONNO]-type dibenzylzirconium
complexes with diaminoethane and diaminocyclohexane bridge
[7e]. The 13C NMR analysis of poly(vinylcyclohexane) from entry 4
revealed an isotactic structure ([mm] ¼ 0.77) (Fig. 5). This result
indicates that it is easier to control VCH insertion and direction of
poly(vinylcyclohexane) chain around a Zr center for this bulkier
monomer compared to 1-hexene polymerization. The same high
isotacticity in vinylcyclohexane polymerization was observed for
the abovementioned [ONNO]-type dibenzylzirconium complexes,
regardless of the nature of the phenolate substituents [7e].
On the other hand, 1-hexene or vinylcyclohexene polymeriza-
tion using hafnium complex 5 gave only oligomers (Table 2, entries
4 and 5; Table 3, entries 9 and 10). The formation of a lower
molecular weight polymer with an [OSSO]-type hafnium complex
was also observed by Okuda et al. in styrene polymerization [5n].
However, it is quite unusual that the oligomers were formed with
hafnium catalyst systems.
The results of propylene polymerization with zirconium
dichloro complex 7 and titanium dichloro isomeric mixture 8a/8b
are summarized in Table 4.
Polymerization runs have been carried out at varied tempera-
tures (5, 40 and 60 ꢀC). The catalytic activity was found to increase
with an increasing temperature, with a molecular weight of poly-
propylene being the highest at 5 ꢀC (7: Mw ¼ 3200; 8a/8b:
Mw ¼ 2430000, Table 4, entries 11e16). In the cases of polymeri-
zation runs at 5 and 40 ꢀC using 8a/8b the differential scanning
calorimetry (DSC) thermograms of polypropylene samples show
additional peaks with melting temperatures above 160 ꢀC, indi-
cating a presence of an isotactic polymer (Fig. 6). However, at 60 ꢀC
atactic polypropylene is formed and only a peak below 100 ꢀC was
observed. This can be rationalized by a reversible conversion of 8a
into 8b above 60 ꢀC revealed by VT NMR studies in toluene-d8. At
Table 4
Polymerization of propylene catalyzed by zirconium complex
7
and titanium
complex 8 with TIBA/[Ph3C][B(C6F5)4].a
Entry Catalyst Temp. (ꢀC) Activityb Mw
Mw/Mn
Tm (ꢀC)
c
c
11
12
13
14
15
16
7
7
7
8
8
8
5
40
60
5
40
60
350
1250
1120
22
45
63
3220
2770
2400
1.7
1.7
1.7
n.d.
n.d.
n.d.
164.7/115.6
162.7/104.1
94.2
2430000 22.2
974000 33.9
488000 22.2
a
Conditions: 3.0 L autoclave, toluene (1000 mL), propylene (100 g), catalyst
mol, TIBA ¼ 1.5 mmol, [Ph3C][B(C6F5)4] 20.0 mol, polymerization time
90 min.
10.0
m
m
b
In kg mol(cat)ꢁ1
Determined by GPC with polystyrene standards.
.
Fig. 6. Melting temperatures of polypropylene produced using 8a/8b/TIBA/[Ph3C][B
(C6F5)4].
c

1798
M. Konkol et al. / Journal of Organometallic Chemistry 696 (2011) 1792e1802
5 oC
rings increases the catalyst activity in isospecific polymerization of
vinylcyclohexene [7e] and 1-hexene [7j]. The polymerization of
liquid propylene catalyzed by the titanium dichloro isomeric
mixture afforded at 5 ꢀC ultrahigh molecular weight atactic/
isotactic polypropylene mixtures. As a result of reversible conver-
sion of the C2-symmetrical to the C1-symmetrical isomer above
60 ꢀC, at 60 ꢀC only atactic polypropylene was obtained.
60 oC
40 oC
4. Experimental
All manipulations of air- and moisture-sensitive compounds
were performed under an inert atmosphere of nitrogen using a VAC
glovebox or standard Schlenk-line techniques. Toluene, pentane,
hexane, THF, diethyl ether and dichloromethane were dried by
passage through activated alumina towers and collected under
nitrogen using the Glass Contour Solvent Purification System.
ZrCl2(NMe2)2(THF)2 was prepared according to the published
procedure [10]. Titanium tetrachloride, zirconium tetrabenzyl,
hafnium tetrabenzyl and all other chemicals were commercially
available and were used as received unless stated otherwise.
Vinylcyclohexane and 1-hexene were stored over activated alumina
and molecular sieves 13X and were deoxygenated by bubbling
a stream of dry nitrogen gas before use. Triisobutylaluminum (TIBA)
(1 M solution in toluene) and 2 types of poly(methylaluminoxane),
namely, PMAO (2.6 M solution in toluene) and TMAO (3.4 M solution
in hexane) were purchased from Tosoh Finechem. Co., Ltd. (PMAO-S
and TMAO-341). Triphenylcarbenium tetrakis(pentafluorophenyl)
borate (denoted as F20) was purchased from Asahi Glass Co., Ltd. and
used as a 0.0050 M toluene solution. Tris(pentafluorophenyl)borane
(denoted as F15) was purchased from Tokyo Chemical Industry Co.,
Ltd. and used as a 0.016 M toluene solution.
1
2
3
4
5
6
7
log Aw
Fig. 7. GPC traces of polypropylene produced using 8a/8b/TIBA/[Ph3C][B(C6F5)4].
lower temperatures a mixture of C2- and C1-symmetrical isomers
exists in solution, leading to isotactic/atactic polypropylene,
respectively. Above 60 ꢀC no cis-
a structure is maintained and
atactic polypropylene is formed. Moreover, the gel permeation
chromatography (GPC) data of polypropylene samples revealed
broad molecular weight distribution. The data for polypropylene
show a trimodal distribution (Fig. 7). The intensity of the highest
peak was found to decrease with increasing the polymerization
temperature, while the intensity of other two peaks increased with
increasing temperature. The results of DSC, NMR and GPC
measurements show that the polymer melting at higher-temper-
ature has a higher molecular weight than the one melting at lower
temperature. Therefore, the GPC curve changed with polymeriza-
tion temperature that reflects the conformational change of
complex 8.
The zirconium complex 7 exhibits higher activity than the
titanium complex 8 and it affords polymers with a lower molecular
weight and a narrower molecular weight distribution. The rela-
tionship observed is similar to that reported for 1-hexene poly-
merization using [ONNO]-type complex [7j].
NMR spectra were recorded on a JEOL AL400 (1H, 399.6 MHz;
13C, 100.4 MHz) spectrometer at 25 ꢀC unless stated otherwise.
Mass spectra were recorded using a HewlettePackard HP-5970B
instrument. High-resolution mass spectra were recorded using
a JEOL JMS-T100GC spectrometer and elemental analyses were
performed by Sumika Chemical Analysis Service Ltd. using an
ELEMENTAR element analyzer. Molecular weights (Mw and Mn) and
molecular weight distributions (Mw/Mn) were determined by high
temperature GPC and calibrated using polystyrene standards. GPC
analysis was performed with an HLC-8121GPC/HT liquid chro-
matograph at 152 ꢀC in o-dichlorobenzene using a TSK-GEL
GMHHR-H(20)HT column. Differential scanning calorimetry (DSC)
melting curves were recorded at a rate of 5 ꢀC/min using a Perkin
Elmer Diamond DSC instrument. The melting point (Tm) of copol-
ymers was measured from the second heating.
3. Conclusions
In conclusion, a series of group 4 metal complexes with the
tetradentate bis(phenolate) [OSSO]-type ligand possessing elec-
tron-withdrawing substituents on the phenolate rings have been
prepared. Configurationally stable C2-symmetrical complexes were
obtained for zirconium and hafnium, as revealed by NMR spec-
troscopy and X-ray crystal structure diffraction analysis. For smaller
titanium a mixture of cis-
a
(trans(O,O)-cis(S,S)) and cis-
b
(cis(O,O)-
4.1. 2-Bromomethyl-4,6-di-tert-butylphenol (1)
cis(S,S)) isomers is formed. The C2-symmetrical isomer converts
reversibly to the C1-symmetrical one at temperatures above 60 ꢀC.
Upon activation with poly(methylaluminoxane) and tris(penta-
fluorophenyl)borane the zirconium dibenzyl complexes are active
in polymerization of 1-hexene and vinylcyclohexane, affording
atactic poly(1-hexene) and isotactic poly(vinylcyclohexane),
respectively. However, in both cases an introduction of the elec-
tron-withdrawing substituents on phenolate rings did not result in
an increase in catalytic activity. This finding indicates that the
polymerization activity of zirconium dibenzyl complexes sup-
ported by the [OSSO]-type 1,4-dithiabutanediyl-bridged bis
This compound was prepared by modification of a literature
procedure [11]. To a clear solution of 2,4-di-tert-butylphenol
(8.70 g, 42.17 mmol) in glacial acetic acid (25 mL) para-
formaldehyde (1.40 g, 46.62 mmol, 1.11 equiv.) was added at rt. The
resulting slurry was stirred for 2 h at rt. A 5.1 M HBr solution in
acetic acid (25 mL, 127.35 mmol, 3.02 equiv.) was then dropwise
added resulting in the formation of a yellow clear solution. After
30 min of stirring acetic acid was removed in vacuum yielding
orange viscous oil. The oil was stored at ꢁ30 ꢀC and after 3 h an
orange solid material formed. This material was washed with
a small amount of diethyl ether and dried thoroughly in a stream of
nitrogen for several hours to yield 10.6 g (84%) of a light orange
(phenolate) ligand with
a Salan-type methylene spacer is
presumably derived primarily from the bulkiness of phenolate
substituents (activity decreases on reduction of bulkiness from tBu
to Br). This trend stands in contrast with the results from Kol et al.
for the diamine bis(phenolate) complexes, showing that incorpo-
ration of the electron-withdrawing halo substituents on phenolate
powder.
t
1H NMR (399.6 MHz, CDCl3):
d
¼ 1.22 (s, 9H, Bu), 1.36 (s, 9H,
tBu), 4.50 (s, 2H, CH2), 5.20 (s, 1H, OH), 7.02 (d, J ¼ 2.4 Hz, 1H, Ar),
7.26 (d, J ¼ 2.4 Hz, 1H, Ar).

M. Konkol et al. / Journal of Organometallic Chemistry 696 (2011) 1792e1802
1799
4.2. 2,20-[Ethane-1,2-diylbis(sulfanediylmethylene)]bis(4,6-di-tert-
butylphenol) ([OSSO]H2) (2)
2H, CH2, AB system), 2.82e2.86 (d, 4H, 2ꢂCH2, AB system, over-
lapping), 3.26 (d, J ¼ 14.8 Hz, 2H, CH2, AB system), 6.89 (d,
J ¼ 6.8 Hz, 4H, Ar), 6.98 (d, J ¼ 2.4 Hz, 2H, Ar), 7.08 (t, J ¼ 7.2 Hz, 2H,
Ar), 7.18 (t, J ¼ 7.2 Hz, 4H, Ar), 7.60 (d, J ¼ 2.4 Hz, 2H, Ar).
This compound was prepared according to a literature proce-
dure [5g].
13C{1H} NMR (100.4 MHz, C6D6):
d
¼ 35.6 (CH2), 36.1 (CH2), 58.5
t
1H NMR (399.6 MHz, C6D6):
d
¼ 1.28 (s, 18H, Bu), 1.61 (s, 18H,
(CH2Ph), 110.6 (CAreBr), 115.6 (CAreBr), 124.0 (Ar), 126.9 (Ar), 128.8
(Ar), 130.6 (Ar), 130.9 (Ar), 135.3 (Ar), 144.6 (Ar), 157.4 (CAreO).
Anal. Calc. for C30H26Br4O2S2Zr (MW ¼ 893.50): C, 40.33; H,
2.93. Found: C, 40.40; H, 2.90. Yellow block crystals were grown
from a dichloromethane/hexane solution at ꢁ35 ꢀC.
tBu), 2.13 (s, 4H, CH2), 3.33 (s, 4H, CH2), 6.74 (s, 2H, OH), 6.81 (d,
J ¼ 2.4 Hz, 2H, Ar), 7.46 (d, J ¼ 2.4 Hz, 2H, Ar). 13C{1H} NMR
(100.4 MHz, C6D6):
d
¼ 30.0 (CMe3), 30.4 (CH2), 31.8 (CMe3), 34.1
(CH2), 34.3 (CMe3), 35.3 (CMe3), 121.8 (CAr), 124.0 (CHAr), 125.5
(CHAr), 137.6 (CAr), 142.4 (CAr), 152.7 (CAr).
4.6. {2,20-[Ethane-1,2-diylbis(sulfanediylmethylene)]bis(4,6-di-
tert-butylphenolato)} dibenzylhafnium ([OSSO]HfBz2) (5)
4.3. 2,20-[Ethane-1,2-diylbis(sulfanediylmethylene)]bis(4,6-
dibromophenol) ([OSSO]BrH2) (3)
The ligand precursor 2 (0.50 g, 0.94 mmol) in pentane (8 mL)
was added dropwise at rt to a solution of HfBz4 (0.510 g, 0.94 mmol)
in toluene (10 mL). The reaction mixture was stirred at rt for 3 h.
The solvents were removed in vacuum and pentane (10 mL) was
added. Removal of pentane afforded 0.48 g (57%) of 5 as an off-
white solid.
To a solution of 2,4-dibromo-6-(bromomethyl)phenol (5.00 g,
14.50 mmol) in THF (30 mL) 1,2-ethanedithiol (0.71 g, 7.54 mmol,
0.52 equiv.) was added dropwise at rt. After complete dissolution
triethylamine (1.467 g, 14.50 mmol, 1.00 equiv.) was added dropwise.
Awhite precipitate formed and the flaskwarmed up. White slurry was
stirred at rt in the dark for 24 h. The white precipitate was removed by
filtration and the filtrate was concentrated in vacuum yielding yellow
oil. Diethyl ether was added and a yellow solution was separated from
a yellow smeary material by decantation. Diethyl ether was concen-
trated in vacuum affording yellow viscous oil. After addition of
dehydrated methanol the resulting solution was stored overnight
at ꢁ25 ꢀC. An off-white precipitate, which had formed, was filtered off
andwashedwithasmall amountofmethanol. Pentanewas addedand
the resulting white slurry was stirred for ca.1 h (within this time a bit
sticky precipitate became fine). The precipitate was then filtered off,
washed with pentane and dried to yield 2.92 g (64%) of 3.
1H NMR (399.6 MHz, C6D6):
d
¼ 1.24 (s, 18H, tBu), 1.70 (d,
J ¼ 8.8 Hz, 2H, CH2, AB system), 1.81 (s, 18H, tBu), 1.86 (d, J ¼ 9.2 Hz,
2H, CH2, AB system, overlapping), 2.47 (d, J ¼ 11.6 Hz, 2H, CH2, AB
system), 2.90 (d, J ¼ 11.2 Hz, 14.8 Hz, 4H, 2ꢂCH2, AB system, over-
lapping), 3.07 (d, J ¼ 14.0 Hz, 2H, CH2, AB system), 6.53 (d,
J ¼ 2.4 Hz, 2H, Ar), 6.80 (t, J ¼ 7.2 Hz, 2H, Ar), 7.11 (t, J ¼ 7.8 Hz, 4H,
Ar), 7.32 (d, J ¼ 7.2 Hz, 4H, Ar), 7.54 (d, J ¼ 2.4 Hz, 2H, Ar).
13C{1H} NMR (100.4 MHz, C6D6):
34.2, 34.3, 35.4, 35.6 (CMe3/CH2), 75.3 (CH2Ph), 122.0 (Ar), 122.5
(Ar), 124.6 (Ar), 125.2 (Ar), 127.9 (Ar), 128.1 (Ar), 138.6 (Ar), 141.4
(Ar), 147.8 (Ar), 158.0 (CAr-O).
d
¼ 30.8 (CMe3), 31.7 (CMe3),
1H NMR (399.6 MHz, CD2Cl2):
d
¼ 2.69 (s, 4H, CH2S), 3.77 (s, 4H,
EI-MS m/z: 799.3 ([M ꢁ Bz]).
CCH2), 6.16 (s, 2H, OH), 7.33 (d, J ¼ 2.4 Hz, 2H, Ar), 7.56 (d, J ¼ 2.4 Hz,
2H, Ar).
4.7. {2,20-[Ethane-1,2-diylbis(sulfanediylmethylene)]bis(4,6-
13C{1H} NMR (100.4 MHz, CD2Cl2):
112.0 (CAreBr), 112.9 (CAreBr), 128.2 (CAr), 133.1 (CH), 133.8 (CH),
150.7 (CAreO).
d
¼ 31.7 (CH2), 32.0 (CH2),
dibromophenolato)} dibenzylhafnium ([OSSO]BrHfBz2) (5Br
)
The ligand precursor 3 (0.30 g, 0.48 mmol) was dissolved in
toluene (3 mL) and added dropwise at rt to a solution of HfBz4
(0.26 g, 0.48 mmol) in toluene (7 mL). The reaction mixture was
stirred at rt for 3 h. Toluene was removed in vacuum and pentane
(5 mL) was added. Filtration of a beige precipitate, washing with
Anal. Calc. for C16H14Br4O2S2 (MW ¼ 622.03): C, 30.89; H, 2.27.
Found: C, 31.40; H, 2.40.
4.4. {2,20-[Ethane-1,2-diylbis(sulfanediylmethylene)]bis(4,6-di-
tert-butylphenolato)} dibenzylzirconium ([OSSO]ZrBz2) (4)
pentane and drying in vacuum afforded 0.42 g (89%) of 5Br
.
1H NMR (399.6 MHz, CD2Cl2):
d
¼ 1.49 (d, J ¼ 10.0 Hz, 2H, CH2,
This compound was prepared according to a literature proce-
dure [5g]. The ligand precursor 2 (0.20 g, 0.38 mmol) was dissolved
in toluene (5 mL) and added dropwise to a solution of ZrBz4
(0.173 g, 0.38 mmol) in toluene (3 mL). The reaction mixture was
stirred at rt for 4 h. Toluene was removed in vacuum and pentane
(ca. 4 mL) was added. Removal of pentane afforded 0.25 g (82%) of 4
AB system), 1.56 (d, J ¼ 9.6 Hz, 2H, CH2, AB system), 2.27 (d,
J ¼ 10.0 Hz, 2H, CH2, AB system), 2.77e2.84 (d, 4H, 2ꢂCH2, AB
system, overlapping), 3.25 (d, J ¼ 14.8 Hz, 2H, CH2, AB system),
6.97e7.02 (m, 8H, Ar), 7.15 (t, J ¼ 7.6 Hz, 4H, Ar), 7.65 (d, J ¼ 2.0 Hz,
2H, Ar).
13C{1H} NMR (100.4 MHz, CD2Cl2):
d
¼ 35.8 (CH2), 37.5 (CH2),
as a yellow solid.
64.6 (CH2Ph), 111.2 (CAreBr), 115.6 (CAreBr), 123.7 (Ar), 127.0 (Ar),
129.0 (Ar),129.7 (Ar),131.3 (Ar),135.5 (Ar),144.6 (Ar),157.2 (CAreO).
EI-MS m/z: 889.7 ([M ꢁ Bz]).
t
1H NMR (399.6 MHz, C6D6):
d
¼ 1.24 (s, 18H, Bu), 1.75 (s þ m,
t
20H, BuþCH2), 1.85 (d, J ¼ 9.2 Hz, 2H, CH2, AB system), 2.10 (d,
J ¼ 8.8 Hz, 2H, CH2, AB system), 2.60 (d, J ¼ 9.2 Hz, 2H, CH2, AB
system), 2.85 (d, J ¼ 14.4 Hz, 2H, CH2, AB system), 3.03 (d,
J ¼ 14.8 Hz, 2H, CH2, AB system), 6.50 (d, J ¼ 2.4 Hz, 2H, Ar), 6.96 (t,
J ¼ 7.2 Hz, 2H, Ar), 7.12 (t, J ¼ 7.6 Hz, 4H, Ar), 7.23 (d, J ¼ 7.6 Hz, 4H,
Ar), 7.45 (d, J ¼ 2.4 Hz, 2H, Ar).
Yellow block crystals were grown from a dichloromethane
solution at ꢁ35 ꢀC.
4.8. {2,20-[Ethane-1,2-diylbis(sulfanediylmethylene)]bis(4,6-di-
tert-butylphenolato)} bis(dimethyl) amidozirconium ([OSSO]Zr
(NMe2)2) (6)
4.5. {2,20-[Ethane-1,2-diylbis(sulfanediylmethylene)]bis(4,6-
dibromophenolato)} dibenzylzirconium ([OSSO]BrZrBz2) (4Br
)
The ligand precursor 2 (0.50 g, 0.94 mmol) in THF (ca. 10 mL)
was added dropwise at rt to a suspension of NaH (0.046 g,
1.93 mmol, 2.05 equiv.) in THF (10 mL). After 30 min a clear solution
This complex was prepared in an analogous way as 4 with 89%
yield.
1H NMR (399.6 MHz, CD2Cl2):
system), 1.60 (d, J ¼ 10.0 Hz, 2H, CH2, AB system), 2.29 (d, J ¼ 8.4 Hz,
formed that was stirred at rt for
2 h. A solution of
d
¼ 1.45 (d, J ¼ 8.0 Hz, 2H, CH2, AB
ZrCl2(NMe2)2(THF)2 (0.371 g, 0.94 mmol) in THF (5 mL) was
subsequently syringed in at rt. The resulting milky solution was

1800
M. Konkol et al. / Journal of Organometallic Chemistry 696 (2011) 1792e1802
stirred overnight at rt and then filtered using a syringe filter with
a PTFE membrane. THF was removed in vacuum and pentane (4 mL)
was added. The resulting white precipitate was filtered, washed
with hexane/pentane and dried in vacuum to yield 0.486 g (73%) of
6 as a white powder.
was concentrated in vacuum until dryness and pentane was added.
A red precipitate formed that was filtered off, washed with pentane
and dried in vacuum to afford 0.195 g (80%) of 8. The NMR analysis
in C6D6 revealed two isomers, C1- and C2-symmetric, in a ratio
59%:41%, respectively. In CD2Cl2 this ratio was 80%:20%.
1H NMR (399.6 MHz, C6D6):
d
¼ 1.32 (s, 18H, tBu), 1.68 (d,
J ¼ 9.6 Hz, 2H, SCH2, AB system),1.74 (s, 18H, tBu), 2.08 (d, J ¼ 9.2 Hz,
2H, SCH2, AB system), 3.15 (d, J ¼ 13.6 Hz, 2H, CCH2, AB system),
3.39 (s, 12H, NMe2), 3.76 (d, J ¼ 13.6 Hz, 2H, CH2C, AB system), 6.67
(d, J ¼ 2.4 Hz, 2H, Ar), 7.51 (d, J ¼ 2.8 Hz, 2H, Ar).
4.11.1. C1-Symmetric isomer
1H NMR (399.6 MHz, CD2Cl2):
d
¼ 1.22 (s, 9H, tBu), 1.28 (s, 18H,
tBu), 1.57 (s, 9H, tBu), 2.51e2.59 (m, 1H, CH2, overlapping),
3.17e3.25 (m, 1H, CH2), 3.41e3.45 (td, J ¼ 11.6 Hz, 2.8 Hz, 1H, CH2),
3.66e3.70 (td, J ¼ 13.2 Hz, 2.8 Hz, 1H, CH2), 3.91 (d, J ¼ 14.4 Hz, 1H,
CH2), 4.07 (d, J ¼ 12.4 Hz, 1H, CH2), 4.46 (d, J ¼ 14.4 Hz, 1H, CH2,
overlapping), 4.63 (d, J ¼ 12.4 Hz,1H, CH2), 7.01 (d, J ¼ 2.0 Hz,1H, Ar,
overlapping), 7.02 (d, J ¼ 2.4 Hz, 1H, Ar, overlapping), 7.27 (d,
J ¼ 2.4 Hz, 1H, Ar), 7.32 (d, J ¼ 2.4 Hz, 1H, Ar).
13C{1H} NMR (100.4 MHz, C6D6):
33.4, 34.2, 35.6, 36.2 (CMe3/CH2), 45.3 (NMe2), 123.1 (CAr), 124.2
(CHAr), 125.2 (CHAr), 138.2 (CAr), 140.1 (CAr), 159.4 (CAreO).
d
¼ 30.2 (CMe3), 31.9 (CMe3),
4.9. {2,20-[Ethane-1,2-diylbis(sulfanediylmethylene)]bis(4,6-
dibromophenolato)}bis(dimethyl) amidozirconium ([OSSO]BrZr
13C{1H} NMR (100.4 MHz, CD2Cl2):
d
¼ 30.2 (CMe3), 30.4 (CMe3),
(NMe2)2) (6Br
)
31.5 (2ꢂCMe3), 32.2, 34.8, 35.6, 35.8 (CH2/CMe3), 37.7 (CH2), 38.4
(CH2), 40.4 (CH2), 122.6 (Ar), 124.5 (Ar), 124.8 (Ar), 125.5 (Ar), 125.6
(Ar), 127.1 (Ar), 136.8 (Ar), 138.2 (Ar), 145.2 (Ar), 145.3 (Ar), 161.1
(CAreO), 161.4 (CAreO), one aliphatic resonance obscured.
The ligand precursor 3 (0.50 g, 0.80 mmol) in THF (ca. 10 mL)
was added dropwise at rt to a suspension of NaH (0.039 g,
1.64 mmol, 2.05 equiv.) in THF (10 mL). A pale yellow cloudy
solution formed that was stirred at rt for 3 h. Within this time the
colour turned to pale brown. A solution of ZrCl2(NMe2)2(THF)2
(0.316 g, 0.80 mmol) in THF (5 mL) was subsequently syringed in at
rt. The resulting pale yellow slurry was stirred overnight at rt and
then filtered using a syringe filter with a PTFE membrane. THF was
removed in vacuum and pentane (4 mL) was added. Removal of
pentane afforded a bit sticky solid material. It was dissolved in
dichloromethane and the product was precipitated with pentane.
Filtration, washing with pentane and drying in vacuum gave
0.380 g (59%) of 6Br as an off-white powder.
4.11.2. C2-Symmetric isomer
1H NMR (399.6 MHz, CD2Cl2):
d
¼ 1.29 (s, 18H, tBu, overlapping),
1.60 (s, 18H, tBu, overlapping), 2.51e2.59 (m, 2H, CH2, overlapping),
2.86 (d, J ¼ 8.8 Hz, 2H, CH2, AB system), 3.83 (d, J ¼ 14.8 Hz, 2H, CH2,
AB system), 4.44 (d, J ¼ 14.0 Hz, 2H, CH2, AB system, overlapping),
6.93 (d, J ¼ 1.8 Hz, 2H, Ar), 7.38 (d, J ¼ 1.8 Hz, 2H, Ar).
13C{1H} NMR (100.4 MHz, CD2Cl2):
d
¼ 30.4 (CMe3), 31.6 (CMe3),
31.4, 34.2, 35.7 (CH2/CMe3), 38.3 (CH2), 122.8 (Ar), 125.0 (Ar), 126.3
(Ar), 138.4 (Ar), 144.7 (Ar), 160.2 (CAreO).
Anal. Calc. for C32H48Cl2O2S2Ti (MW ¼ 647.63): C, 59.35; H, 7.47.
1H NMR (399.6 MHz, CD2Cl2):
CH2), 3.23 (s, 12H, NMe2), 3.71 (br, 4H, CH2, overlapping), 7.10 (d,
d
¼ 1.73 (br, 2H, CH2), 2.54 (br, 2H,
Found: C, 58.80; H, 7.30.
J ¼ 2.8 Hz, 2H, Ar), 7.63 (d, J ¼ 2.8 Hz, 2H, Ar).
4.12. Typical neat 1-hexene polymerization experiment
13C{1H} NMR (100.40 MHz, CD2Cl2):
d
¼ 34.1 (CH2), 35.9 (CH2),
45.0 (NMe2), 109.9 (CAreBr), 115.3 (CAreBr), 126.8 (CAr), 132.0
(CHAr), 135.8 (CHAr), 158.5 (CAreO).
In a glovebox, a solution of F15 (16.0
was combined with a solution of a bis(phenolate) complex
(12.0 mol) and 1-hexene (9.0 mL). The reaction mixture was
mmol) in 1-hexene (1.0 mL)
m
4.10. {2,20-[Ethane-1,2-diylbis(sulfanediylmethylene)]bis(4,6-di-
tert-butylphenolato)} dichlorozirconium ([OSSO]ZrCl2) (7)
stirred at room temperature for 2 h. It was then quenched by
adding methanol (1.0 mL). After several minutes the volatiles were
removed in a high vacuum at 80 ꢀC for 4 h, affording poly(1-hex-
ene) as colorless sticky oil. Samples of poly(1-hexene) were
analyzed by means of GPC and 13C NMR measurements.
To a solution of complex 6 (0.50 g, 0.71 mmol) in toluene (10 mL)
TMSCl (0.77 g, 7.06 mmol,10.00 equiv.) was dropwise added at 0 ꢀC.
The solution was warmed up to 35 ꢀC and stirred for 3 h. The
volatiles were removed in vacuum and pentane was added. The
resulting white precipitate was filtered off, washed with pentane
4.13. Typical vinylcyclohexane polymerization experiment
and dried in vacuum to yield 0.330 g (68%) of 7 as a white powder.
In a glovebox, a solution of F15 (16.0
was combined with a solution of a bis(phenolate) complex
(12.0 mol) and vinylcyclohexane (5.0 mL) in toluene (4.0 mL). The
reaction mixture was stirred at room temperature for 2 h. The
polymerization reaction was quenched by adding methanol
(1.0 mL). After several minutes the volatiles were removed in a high
vacuum at 80 ꢀC for 4 h, affording poly(vinylcyclohexane) as
colorless sticky oil. Samples of poly(vinylcyclohexane) were
analyzed by means of GPC and 13C NMR measurements.
mmol) in toluene (1.0 mL)
t
1H NMR (399.6 MHz, C6D6):
d
¼ 1.27 (s, 18H, Bu), 1.80 (s, 18H,
tBu), 3.11 (d, J ¼ 13.6 Hz, 2H, CH2C, AB system), 4.12 (d, J ¼ 13.6 Hz,
2H, CH2C, AB system), 6.56 (d, J ¼ 2.4 Hz, 2H, Ar), 7.55 (d, J ¼ 2.4 Hz,
2H, Ar), both SCH2 resonances obscured by tBu ones.
m
13C{1H} NMR (100.4 MHz, C6D6):
d
¼ 30.5 (CMe3), 31.0 (SCH2),
31.7 (CMe3), 34.4 (CMe3), 35.6 (CH2), 36.8 (CMe3), 120.6 (CAr), 125.2
(CHAr), 125.9 (CHAr), 138.9 (CAr), 142.7 (CAr), 157.4 (CAreO).
Anal. Calc. for C32H48Cl2O2S2Zr (MW ¼ 690.98): C, 55.62; H, 7.00.
Found: C, 55.20; H, 7.10. Colorless block crystals were grown from
a dichloromethane/pentane solution at ꢁ35 ꢀC.
4.14. Typical propylene polymerization experiment
4.11. {2,20-[Ethane-1,2-diylbis(sulfanediylmethylene)]bis(4,6-di-
tert-butylphenolato)} dichlorotitanium ([OSSO]TiCl2) (8)
An autoclave with an inner volume of 3.0 L was dried under
vacuum. After charging with toluene (1.0 mL) and liquid propylene
(100 g), the autoclave was corrected at given temperature (5, 40,
60 ꢀC). After the system had stabilized, TIBA (1.5 mmol) was added
to the reaction mixture. Subsequently, a bis(phenolate) complex
To a solution of the ligand precursor 2 (0.20 g, 0.38 mmol) in
toluene (5 mL) TiCl4 (0.071 g, 0.38 mmol) was added dropwise at rt
with vigorous stirring. The solution turned immediately red. The
reaction mixture was stirred for ca. 1 h and then filtered. Toluene
(10.0
mmol) and F20 (20.0 mmol) were added. Polymerization was
carried out for 90 min, while the temperature was maintained. The

M. Konkol et al. / Journal of Organometallic Chemistry 696 (2011) 1792e1802
1801
8507;
polymerization mixture was quenched with methanol (5.0 mL).
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After a few minutes the gas was vented and the mixture was then
poured into methanol (1.0 L) with hydrochloric acid (1 M, 10 mL).
The polymer was isolated by filtration, washed with fresh methanol
and dried in a high vacuum at 80 ꢀC for 4 h.
4.15. X-ray crystallography
Crystals of 4Br, 5Br and 7 suitable for X-ray analysis were grown
from a dichloromethane/hexane (4Br), dichloromethane (5Br) or
dichloromethane/pentane (7) solution at ꢁ35 ꢀC. X-ray diffraction
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2
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hydrogen atoms and the calculations were performed using the
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Hydrogen atomswere refined isotropicallyor usingtheridingmodel.
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Acknowledgments
(e) K.-H. Tam, J.C.Y. Lo, Z. Guo, M.C.W. Chan, J. Organomet. Chem. 692 (2007)
4750;
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(i) R.K.J. Bott, M. Hammond, P.N. Horton, S.J. Lancaster, M. Bochmann, P. Scott,
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The authors thank Mr. Shunji Murao and Ms. Asami Tanaka for
the experimental assistance, Mr. Takashi Kohara for NMR analysis
of polymers, Mr. Mitsuharu Mitobe for GPC analysis and Mr. Tsu-
tomu Suzuki for the DSC analysis.
Appendix A. Supplementary material
(j) S. Groysman, E.Y. Tshuva, I. Goldberg, M. Kol, Z. Goldschmidt, M. Shuster,
Organometallics 23 (2004) 5291.
CCDC 793742e793744 contain the supplementary crystallo-
graphic data for compounds 4Br, 5Br and 7. These data can be
obtained free of charge from The Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
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