Syntheses, characterization, and ethylene polymerization of titanium and zirconium complexes with [N, O] ligands

Article abstract of DOI:10.1039/b907598d

Bidentate monoanionic ligands 2-(benzo[d]thiazol-2-yl) phenol (La), 2-(benzo[d]thiazol-2-yl)-6-methylphenol (Lb), 2-(benzo[d]thiazol-2-yl)-6-tert- butyl-4-methylphenol (Lc), 2-(benzo[d]thiazol-2-yl)-6-chlorophenol (Ld), and 2-(benzo[d]thiazol-2-yl)-4-chlorophenol (Le) have been synthesized. Reactions of TiCl₄(THF)₂ or ZrCl₄ with La-Le afford the corresponding titanium complexes Ti[ON]₂^RCl₂ [R = 6-Me (2b); R = 4-Me-6-Bu^t (2c)], and zirconium complexes Zr[ON]₂^RCl₂ [R = H (3a); R = 6-Me (3b); R = 4-Me-6-Bu^t (3c); R = 6-Cl (3d); R = 4-Cl (3e)], and Zr[ON ^R]HCl₄·THF [R = 6-Me (4b)], respectively. Complexes 2a-4b were characterized by IR, ¹H NMR spectra and elemental analysis. The molecular structures of La, 2b, 2c, 3b, 3c and 4b have been characterized by single-crystal X-ray diffraction analyses. The effect of steric hindrance and the coordination metal on the structure of the products has been investigated. When activated by excess methylaluminoxane (MAO), 2b and 2c, 3a-3e and 4b can be used as catalysts for ethylene polymerization and exhibit moderate to good activities.

Full text of DOI:10.1039/b907598d

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www.rsc.org/dalton | Dalton Transactions
Syntheses, characterization, and ethylene polymerization of titanium and
zirconium complexes with [N, O] ligands†
Ai-Quan Jia and Guo-Xin Jin*
Received 16th April 2009, Accepted 13th July 2009
First published as an Advance Article on the web 6th August 2009
DOI: 10.1039/b907598d
Bidentate monoanionic ligands 2-(benzo[d]thiazol-2-yl) phenol (La), 2-(benzo[d]thiazol-2-yl)-
6-methylphenol (Lb), 2-(benzo[d]thiazol-2-yl)-6-tert-butyl-4-methylphenol (Lc), 2-(benzo[d]thiazol-
2-yl)-6-chlorophenol (Ld), and 2-(benzo[d]thiazol-2-yl)-4-chlorophenol (Le) have been synthesized.
Reactions of TiCl4(THF)2 or ZrCl4 with La–Le afford the corresponding titanium complexes
Ti[ON]2RCl2 [R = 6-Me (2b); R = 4-Me-6-But (2c)], and zirconium complexes Zr[ON]2RCl2 [R = H (3a);
R = 6-Me (3b); R = 4-Me-6-But (3c); R = 6-Cl (3d); R = 4-Cl (3e)], and Zr[ONR]HCl4·THF [R = 6-Me
(4b)], respectively. Complexes 2a–4b were characterized by IR, 1H NMR spectra and elemental analysis.
The molecular structures of La, 2b, 2c, 3b, 3c and 4b have been characterized by single-crystal X-ray
diffraction analyses. The effect of steric hindrance and the coordination metal on the structure of the
products has been investigated. When activated by excess methylaluminoxane (MAO), 2b and 2c, 3a–3e
and 4b can be used as catalysts for ethylene polymerization and exhibit moderate to good activities.
non-metallocenes catalysts based on tridentate dianionic [O, N, S]
ligands and bidentate monoanionic [N, O] ligands for ethylene
Introduction
and norbornene polymerization.6,7 Additionally, the tridentate
dianionic arylsulfide ligands could be easily oxidized into bidentate
monoanionic heterocycle-containing [N, O] ligands, according to
literature reported by Moghaddam et al.8 Herein, we described the
syntheses, X-ray crystallographic characterizations, and ethylene
polymerization chemistry of titanium and zirconium complexes
bearing the heterocycle-containing [N, O] ligands (Scheme 1).
In recent years, non-metallocene molecular catalysts, includ-
ing both early and late transition metal complexes, have at-
tracted great attention.1–3 Group 4 metal complexes contain-
ing phenoxy–imine ligands are among the typical examples.2–4
It has been widely known that titanium–zirconium complexes
containing bis(salicylaldiminato) ligands can be used to produce
polyethylene or syndiotactic polypropylene with high molecular
weight and narrow molecular weight distribution, and that the
catalytic behaviors are highly affected by the substituent on
both the phenoxy and the imino groups.3a,3b,4 The work by
the groups of Fujita and Nomura on olefin polymerization
based on group 4 catalysts of phenoxy–amide ligands is well
known,3a,b,5j for example, complex bis[N-(3-cumyl-5- methylsali-
cylidene)cyclohexylaminato]zirconium(IV)dichloride with methy-
laluminoxane (MAO) displayed an ethylene polymerization activ-
ity of 4315 kg of polymer mmol-1 of cat h-1 at 25 ◦C at atmospheric
pressure.3a
In the past decades, considerable effort has been devoted to
the catalyst modification of group 4 non-metallocenes in order
to improve olefin polymerization activity and control polymer
properties such as stereoregularity, comonomer incorporation,
and microstructure.5 However, despite the extensive investiga-
tions of organometallic complexes of salicylaldiminato ligands
in olefin polymerization, few bidentate monoanionic heterocycle-
containing [N, O] ligated titanium(IV) and zirconium complexes
have been described and their reaction chemistry is rarely devel-
oped. Previously, our group has reported both metallocenes and
Results and discussion
Syntheses and characterizations of the titanium and zirconium
complexes
The benzo[d]thiazole-containing ligands Ld and Le are di-
rectly prepared in good yields by condensation reactions of
the corresponding salicyaldehyde with o-aminothiophenol in
boiling ethanol in air for 2 h (possibly due to the existence
of an electron-withdrawing chlorine substituent which bene-
fits the cyclization and dehydrogenation in ligands Ld and
Le), while La–Lc are obtained through additional oxidations
of 2-((2-mercaptophenylimino)methyl)phenol and its derivatives
(Scheme 2). The molecular structure of La was confirmed by
single-crystal X-ray analysis (Fig. 1), and the whole molecule
is almost in the plane. Erker’s group has reported a general
synthesis for titanium complexes with [N, O] ligands in a one-
pot procedure by treatment of titanium tetrachloride with 2
equivalents of N-phenylsalicylaldimine in dichloromethane in
the presence of triethylamine (2 equivalents).9 However, in this
contribution, titanium complexes 2b and 2c are simply synthesized
by the reaction of TiCl4(THF)2 with Lb and Lc in toluene solution
for about 12 h without any base (Scheme 1). When La is used,
the reaction does not lead to the expected structure and gives
precipitate that would not dissolve in ordinary organic solvents. As
for the syntheses of zirconium complexes, the reported method of
Shanghai Key Laboratory of Molecular Catalysis and Innovative
Materials, Department of Chemistry, and Key Lab of Molecular Engineering
of Polymers of Chinese Ministry of Education, Department of Macro-
molecular Science, Fudan University, Shanghai 200 433, China. E-mail:
gxjin@fudan.edu.cn; Fax: +86-21-65641740; Tel: +86-21-65643776
† CCDC reference numbers 727482–727487. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/b907598d
8838 | Dalton Trans., 2009, 8838–8845
This journal is
The Royal Society of Chemistry 2009
©

Scheme 1 Synthesis of titanium and zirconium complexes 2b, 2c, 3a–3e, and 4b.
Scheme 2 Synthetic routes to ligands La–Le.
1
olefin polymerization catalysts (FI catalysts) Zr[NO]2RCl2 involves
a two-step procedure, consisting of ZrCl4 with lithium salts of
C2-symmetric in solution, as deduced on the basis of H NMR
data (see Experimental section). Selected structural parameters,
along with those related titanium and zirconium complexes are
collected in Table 1.
n
ligands, obtained by deprotonation in the presence of BuLi.3a
However, in our paper, similar complexes 3a–3e could be prepared
by adding La–Le to 0.5 equivalents of ZrCl4 in THF in one step
in the absence of base. As for 4b, 1 equivalent ZrCl4 is involved
(Scheme 1).
Fortunately, we obtained the single crystals of 2b, 2c, 3b, 3c and
4b (Fig. 2–6). In the solid state, 2b, 2c, 3b, 3c possess a distorted
octahedral geometry (Fig. 2–5). As for trans-dichloride complex
2c, racemates are found in the crystal. Complex 3c is C2-symmetric,
whereas 2b, 2c, and 3b are nearly C2-symmetric. The structure
provides support for the molecules being C2-symmetric or almost
1
The complexes are fully characterized by H NMR and ele-
mental analyses (see Experimental section). The chemical shift of
phenoxy protons in ligands La–Le are all above 12 ppm, but the
signals disappear in complexes 2b, 2c, 3a–3e, and 4b. Protons
(Ar-H) in complexes 2b, 2c, and 3a–3e are shifted downfield
by approximately 0.05 ppm compared to free ligands, indicating
obvious coordination of the phenoxy and imino nitrogen atoms
to the metal. In 2b, the Ti–O bond lengths are 1.809(3) and
˚
˚
1.850(3) A; the Ti–N bond lengths are 2.279(4) and 2.220(4) A;
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 8838–8845 | 8839
©

Table 1 Summary of crystallographic data for 2b, 2c, 3b, 3c, 4b and related complexes M[ON]2RCl2 (M = Ti, Zr)
Complexes
M–O
M–N
M–Cl
Cl–M–Cl
O–M–O
N–M–N
9
Bis(N-phenylsalicylaldiminato)TiCl2
1.854(1)
1.985(2)
1.994(3)
1.992(3)
1.809(3)
1.850(3)
1.829(3)
1.849(3)
1.980(4)
1.966(4)
1.966(2)
1.986(14)
2.214(14)
2.223(2)
2.355(2)
2.384(3)
2.381(3)
2.279(4)
2.220(4)
2.235(4)
2.219(4)
2.388(4)
2.364(4)
2.392(3)
—
2.299(1)
2.423(9)
2.447(2)
2.454(2)
2.320(2)
2.264(2)
2.345(2)
2.346(2)
2.419(2)
2.407(2)
2.417(1)
2.414(6)
2.442(6)
2.455(6)
2.496(5)
97.6(1)
100.4(5)
88.8(5)
165.1(1)
165.5(1)
93.1(1)
80.7(1)
74.0(1)
174.3(1)
3a
Bis[N-(3-tert-butylsalicylidene)anilinato]ZrCl2
10
Bis(“ferrocene–saliminato”)ZrCl2
Ti[NO]2MeCl2 (2b)
Ti[NO]2tBuCl2 (2c)
Zr[NO]2MeCl2 (3b)
97.4(6)
172.3(7)
97.7(5)
91.8(1)
104.5(2)
152.0(1)
89.4(2)
89.7(2)
82.0(1)
Zr[NO]2tBuCl2 (3c)
Zr[NO]HCl4·THF (4b)
103.9(6)
163.7(1)
176.7(6)
74.7(1)
—
Fig. 1 Molecular structure of La with thermal ellipsoids drawn at the
30% level.
Fig. 3 Molecular structure of Ti[NO]2t-BuCl2 (2c) with thermal ellipsoids
drawn at the 30% level, hydrogen atoms are omitted for clarity.
Fig. 2 Molecular structure of Ti[NO]2MeCl2 (2b) with thermal ellipsoids
drawn at the 30% level, hydrogen atoms are omitted for clarity.
˚
and the Ti–Cl bond lengths are 2.320(2) and 2.264(2) A. For 2c, the
˚
Ti–O bond distances are 1.829(3) and 1.849(3) A, somewhat longer
˚
than that in 2b; the Ti–N bond lengths are 2.235(4) and 2.219(4) A,
Fig. 4 Molecular structure of Zr[NO]2MeCl2 (3b) with thermal ellipsoids
˚
similar to that in 2b; the Ti–Cl bond lengths are 2.345(2) A and
˚
drawn at the 30% level, hydrogen atoms are omitted for clarity.
2.346(2) A, longer than that in 2b. The O–Ti–O bond angle is
104.5(2)◦, which is larger than that in 2b (91.8(1)◦). In complex 3b,
˚
˚
the Zr–O bond distances are 1.980(4) and 1.966(4) A, longer than
bond lengths are 2.419(2) and 2.407(2) A, still longer than that in
that in titanium complexes 2b and 2c; the Zr–N bond lengths are
2b and 2c. The O–Zr–O bond angle in complex 3b (152.0(1)◦) is
much larger than that in complexes 2b and 2c. As for 3c, the Zr–O
˚
2.388(4) and 2.364(4) A, longer than that in 2b and 2c; the Zr–Cl
8840 | Dalton Trans., 2009, 8838–8845
This journal is
The Royal Society of Chemistry 2009
©

Fig. 6 Molecular structure of Zr[NO]MeHCl4(THF) (4b) with thermal
ellipsoids drawn at the 30% level, hydrogen atoms are omitted for clarity.
Fig. 5 Molecular structure of Zr[NO]2t-BuCl2 (3c) with thermal ellipsoids
drawn at the 30% level, hydrogen atoms are omitted for clarity. The
symmetry codes are A: -x, y, -z + 1/2.
hindrance plays a significant role on the coordination property of
these complexes. In 3b and 3c, the configuration of the two chlorine
atoms is in a cis fashion and similar to the zirconium complexes
reported by Fujita et al.3a The Cl–Zr–Cl angles in 3b and 3c are
97.7(5)◦ and 103.9(6)◦, respectively. They are much less than that in
2c (172.3(7)◦), probably due to the larger space of the coordination
centre of the zirconium atom.
According to the structures of complexes 3b and 4b, and related
literature,9 we propose a mechanism for the production of 3a–3e.
The process involves the formation of ZrCl4(THF)2 as the first
step, then 1 equivalent of ligand combines with ZrCl4(THF)2,
which leads to the intermediate complex 4b, and then another
1 equivalent of ligand attacks 4b, followed by elimination of
2 equivalents HCl, which leads to the target complexes 3a–3e
(Scheme 3).
˚
bond length is 1.966(2) A, similar to that in 3b. The Zr–N bond
˚
˚
distance is 2.392(3) A, and the Zr–Cl bond distance is 2.417(12) A,
similar to that in 3b. The O–Zr–O bond angle (163.7(1)◦) is very
near to that in bis[N-(3-tert-butylsalicylidene)anilinato]ZrCl2.3a In
˚
complex 4b, the Zr–O (ligand) bond length is 1.986(14) A, which
is similar to that in 3b and 3c, indicative of obvious interactions
between zirconium and oxygen. Compared to the bond length
˚
of Zr–O (ligand), the Zr–O (THF) (2.214(14) A) is much longer,
presenting a weaker interaction.
Interestingly, the conformation of 2b is different from 2c.
For complex 2b, the two oxygen atoms are oriented cis to one
another (O–Ti–O angle 91.8(1)◦), as stated above, while the two
nitrogen atoms (N–Ti–N 89.4(2)◦) and the two chlorine atoms are
positioned in a cis fashion (Cl–Ti–Cl 97.4(6)◦) too. The latter is a
prerequisite for polymerization catalysis. Though, for complex 2c,
when R1 is bulkier as a tert-butyl group, the two chlorine atoms are
positioned in a trans-fashion (Cl–Ti–Cl 172.3(7)◦). Thus, the steric
Ethylene polymerization
The prepared complexes were briefly investigated in ethylene
polymerization. Titanium and zirconium complexes 2b and 2c,
Scheme 3 Proposed mechanism for preparations of 3a–3e.
The Royal Society of Chemistry 2009
This journal is
Dalton Trans., 2009, 8838–8845 | 8841
©

Table 2 Ethylene polymerization results with titanium and zirconium complexesa
Temp/◦C
Time/min
Activityb
Mv ¥ 10-4
c
Entry
Catalyst
Al : M ratio
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
2b
2b
2b
2b
2b
2b
2c
3a
3b
3b
3b
3b
3b
3b
3b
3c
3d
3e
4b
1000
1500
2000
2500
2000
2000
2000
500
300
500
750
1500
500
500
500
500
500
500
500
20
20
20
20
0
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
30
4
5
20
—
—
7.4
—
—
—
—
3.2
12.0
12.6
14.9
8
Trace
8
Trace
40
96
106
64
48
22
88
60
40
20
20
30
30
30
30
20
50
70
30
20
20
20
d
—
2.6
11.4
1.4
29.6
15.0
—
522
80
Trace
260
5.2
a Conditions: [M] 10 mmol, toluene = 50 mL, ethylene pressure = 1 atm. b Activity in 103 g PE mol M-1 h-1. c Mv measured by the Ubbelohde calibrated
viscosimeter technique. d Polymer can not be fully dissolved.
3a–3e and 4b showed moderate to good activities under the
initiation of MAO. The results are summarized in Table 2.
positioned in a trans-fashion in 2c, indicating that the size of the
coordination metal and steric hindrance both play a significant
role in the geometry of the complexes. When activated by excess
methylaluminoxane (MAO), these complexes can be used as
catalysts for ethylene polymerization. The activity of titanium
complex 2b is lower than those of its analogous complexes 3a–3d.
The activities of zirconium complexes 3a–3e increase as the R1
group is replaced from H to Bu. The highest activity can reach
5.2 ¥ 105 g PE mol Ti-1 h-1, but when R2 is Cl, the corresponding
complex 3e shows only trace activity for ethylene polymerization.
As mentioned above, the two chlorine atoms are positioned
in a trans-fashion in complex 2c, as a result, it does not possess
two available cis-located sites for efficient ethylene polymerization.
In fact, it had trace activity towards ethylene polymerization
(Table 2). Generally, the activity of titanium complex 2b was lower
than that of the zirconium complexes 3a–3d, possibly reflecting
the better activation abilities of MAO towards 3a–3d in the
polymerization. However, when R2 is a chlorine atom, which is
an electron-withdrawing group, complex 3e showed only a trace
of activity for ethylene polymerization. In the 2b/MAO systems,
the yellow mixture turned immediately into an orange solution
as MAO was charged, while in the 3a–3d/MAO systems, the light
yellow mixture turned into a colorless solution as MAO was added.
The highest activity of 2b was 2.0 ¥ 104 g PE mol Ti-1 h-1, while
complex 3c presented the highest activity about 5.2 ¥ 105 g PE mol
Zr1 h-1, 25 times higher than that of 2b. Complex 4b could also
be the catalyst precursor for ethylene polymerization with 2.6 ¥
105 g PE mol Zr-1 h-1 (entry 19). The influence of Al : M ratio and
temperature has also been studied. For complex 3b, it can be seen
from the results in Table 2 that when Al : Zr was 500, it gave the
highest activity, and by increasing the ratio of Al : Zr, a rise in the
molecular weight of the polymer was observed. In addition, as
the temperature increased, the molecular weight went up and then
went down. The activity of complex 3c, having a bulky tert-butyl
group, was somewhat higher than that of complexes 3a, 3b, 3d.
t
Experimental section
General considerations
All the operations were carried out under pure argon atmo-
sphere using standard Schlenk techniques. Tetrahydrofran (THF),
hexane, and toluene were distilled from sodium–benzophenone.
Dichloromethane was distilled from calcium hydride. Commer-
cial reagents, namely, TiCl4, ZrCl4, methylaluminoxane (MAO),
ZrOCl2·8H2O, salicyaldehyde, and o-aminothiophenol were pur-
chased from ACROS Co. The ligands La–Le were prepared
according to the literature.7c,8,11
1H (500 MHz) NMR measurements were obtained on a Bruker
AC500 spectrometer in CDCl3 solution. Elemental analyses for C
and H were carried out on an Elementar III Vario EI analyzer.
[NO]H (La)
A mixture of salicylaldehyde (5 mL, 47.8 mmol), o-amino-
Conclusions
thiophenol (5.50 g, 47.8 mmol), and 30 mL ethanol was heated to
◦
A series of titanium and zirconium complexes with heterocycle-
containing [N, O] ligands have been prepared in one step. The
coordination properties of complexes 2b and 2c, 3b and 3c, and
4b have been investigated to compare with related systems. When
R1 is the bulky tert-butyl group and the coordination metal is the
comparable smaller titanium atom, the two chlorine atoms are
80 C and refluxed for 2 h. The reaction mixture was cooled to
room temperature and the product was obtained as light yellow
crystals [N, O, S] form ligand, which was further oxidized by
ZrOCl2·8H2O (1.61 g, 5 mmol) in refluxed ethanol for 8 h and
then cooled and filtered. La was obtained in 70% (8.20 g) yield.
1H NMR (CDCl3, 500 MHz): d 12.52 (s, 1H, OH), 7.99 (d, 1H,
8842 | Dalton Trans., 2009, 8838–8845
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The Royal Society of Chemistry 2009
©

Ar-H), 7.90 (d, 1H, Ar-H), 7.70 (d, 1H, Ar-H), 7.55 (t, 1H, Ar-H),
7.42 (m, 2H, Ar-H), 7.12 (d, 1H, Ar-H), 6.97 (t, 1H, Ar-H).
Ti[ON]2t-BuCl2 (2c)
This complex was prepared as described above for 2b, starting from
Lc (0.297 g, 1.0 mmol), and TiCl4(THF)2 (0.167 g, 0.5 mmol) in
toluene (15 mL). Workup afforded 2c as a red power. Recrystal-
lization of the product from CH2Cl2/hexane afforded 2c (0.18 g,
[NO]Me (Lb)
Using the same procedure as for the synthesis of La, Lb
(3.14 g) was obtained as light yellow crystals by the reaction of
3-methylsalicyaldehyde (2.45 g, 18.0 mmol), o-aminothiophenol
(2.25 g, 18.0 mmol), ZrOCl2·8H2O (0.61 g, 2 mmol) in a yield of
72%. 1H NMR (CDCl3, 500 MHz): d 12.75 (br, 1H, OH), 7.97 (d,
1H, Ar-H), 7.90 (d, 1H, Ar-H), 7.56 (d, 1H, Ar-H), 7.49 (t, 1H,
Ar-H), 7.42 (m, 2H, Ar-H), 6.87 (t, 1H, Ar-H), 2.36 (s, 3H, CH3).
1
50%) as dark red crystals. H NMR (CDCl3, 500 MHz): d 7.97
(d, 2H, Ar-H), 7.91 (d, 2H, Ar-H), 7.51 (t, 2H, Ar-H), 7.38–7.44
(m, 4H, Ar-H), 7.20 (m, 2H, Ar-H), 2.39 (s, 6H, CH3), 1.63 (s,
18H, tBu). Anal. Calc. for C36H36O2N2S2TiCl2: C, 60.76; H, 5.10;
N, 3.94; Found: C, 60.85; H,5.16; N, 4.06.
Zr[ON]2Cl2 (3a)
[NO]t-Bu (Lc)
To a stirred suspension of ZrCl4 (0.122 g, 0.5 mmol) in 10 mL of
THF, La (0.229 g, 1.0 mmol) in THF (10 mL) was added dropwise
at -78 ◦C. Stirring was maintained for 12 h at room temperature.
The solvent was removed under vacuum and the residue was
extracted in 20 mL of CH2Cl2, filtered, and removal of volatiles
Using the same procedure as the synthesis of La, followed
by additional chromatographic purification, Lc (3.09 g) was
obtained as light yellow crystals by the reaction of 3-tert-butyl-
5-methylsalicyaldehyde (3.82 g, 19.9 mmol), o-aminothiophenol
(2.48 g, 19.9 mmol), ZrOCl2·8H2O (0.61 g, 2 mmol) in a yield of
52%. 1H NMR (CDCl3, 500 MHz): d 12.97 (s, 1H, OH), 7.96 (d,
1H, Ar-H), 7.89 (d, 1H, Ar-H), 7.49 (t, 1H, Ar-H), 7.39 (t, 2H,
Ar-H), 7.20 (d, 1H, Ar-H), 2.35 (s, 3H, CH3), 1.49 (s, 9H, tBu).
1
under vacuum left a yellow powder 3a (0.19 g, 65%). H NMR
(CDCl3, 500 MHz): d 8.00 (d, 2H, Ar-H), 7.91 (d, 2H, Ar-H), 7.70
(d, 2H, Ar-H), 7.52 (t, 2H, Ar-H), 7.44 (m, 4H, Ar-H), 7.11 (d, 2H,
Ar-H), 6.97 (m, 2H, Ar-H). Anal. Calc. for C26H16O2N2S2ZrCl2:
C, 50.81; H, 2.62; N, 4.56; Found: C, 50.27; H, 2.56; N, 4.32.
[NO]o-Cl (Ld)
Zr[ON]2o-MeCl2 (3b)
A mixture of 3-chlorosalicyaldehyde (3.11 g, 19.9 mmol) and
30 mL of ethanol was heated to 80 ◦C, and then a solution
of o-aminothiophenol (2.48 g, 19.9 mmol) in 20 mL of ethanol
was dropwise added. The reaction mixture was refluxed for 2 h
and cooled to room temperature. The product was obtained as
light yellow crystals in a yield of 2.85 g (54%). 1H NMR (CDCl3,
500 MHz): d 12.53 (s, 1H, OH), 8.00 (d, 1H, Ar-H), 7.90 (d, 1H,
Ar-H), 7.70 (d, 1H, Ar-H), 7.51 (t, 1H, Ar-H), 7.42 (m, 1H, Ar-H),
7.12 (d, 1H, Ar-H), 6.96 (t, 1H, Ar-H).
This complex was prepared as described above for 3a, starting
from ZrCl4 (0.122 g, 0.5 mmol), and Lb (0.241 g, 1.0 mmol) in THF
(15 mL). Workup afforded 3b as a yellow power. Recrystallization
of the product from CH2Cl2/hexane afforded 3b (0.19 g, 62%) as
1
colorless crystals. H NMR (CDCl3, 500 MHz): d 8.02 (d, 2H,
Ar-H), 7.89 (d, 2H, Ar-H), 7.63 (d, 2H, Ar-H), 7.53 (t, 2H, Ar-H),
7.43 (t, 2H, Ar-H), 7.23 (m, 2H, Ar-H), 6.86 (t, 2H, Ar-H), 2.37 (s,
6H, CH3). Anal. Calc. for C28H20O2N2S2ZrCl2: C, 52.33; H, 3.14;
N, 4.36; Found: C, 52.28; H, 3.19; N, 4.27.
[NO]p-Cl (Le)
Zr[ON]2t-BuCl2 (3c)
Using the same procedure as for the synthesis of Ld, Le (2.63 g)
was obtained as light yellow crystals by the reaction of 5-chloro-
salicyaldehyde (3.11 g, 19.9 mmol) and o-aminothiophenol (2.48 g,
This complex was prepared as described above for 3a, starting
from ZrCl4 (0.122 g, 0.5 mmol), and Lc (0.297 g, 1.0 mmol) in THF
(15 mL). Workup afforded 3c as a yellow power. Recrystallization
of the product from CH2Cl2/hexane afforded 3c (0.20 g, 55%) as
light yellow crystals. 1H NMR (CDCl3, 500 MHz): d 7.91 (d, 2H,
Ar-H), 7.58 (m, 2H, Ar-H), 7.47 (m, 4H, Ar-H), 7.37–7.31 (m,
4H, Ar-H), 2.36 (s, 6H, CH3), 1.50 (s, 18H, tBu). Anal. Calc. for
C36H36O2N2S2ZrCl2: C, 57.28; H, 4.81; N, 3.71; Found: C, 57.15;
H, 4.89; N, 3.66.
1
19.9 mmol), in a yield of 50%. H NMR (CDCl3, 500 MHz): d
12.52 (s, 1H, OH), 7.97 (d, 1H, Ar-H), 7.90 (d, 1H, Ar-H), 7.63
(s, 1H, Ar-H), 7.52 (t, 1H, Ar-H), 7.42 (t, 1H, Ar-H), 7.29 (d, 1H,
Ar-H), 7.03 (d, 1H, Ar-H).
Ti[ON]2o-MeCl2 (2b)
To a stirred suspension of TiCl4(THF)2 (0.167 g, 0.5 mmol) in
toluene (15 mL), Lb (0.241 g, 1.0 mmol) in 10 mL toluene was
slowly added at -78 ◦C. Stirring was maintained for 12 h at
room temperature, and the solvent was removed under vacuum.
The residue was extracted with dichloromethane, filtered, and the
filtrate was dried to obtain the crude product as a dark red power.
Recrystallization of the product from toluene/hexane afforded 2b
(0.15 g, 50%) as dark red crystals. 1H NMR (CDCl3, 500 MHz): d
7.99 (d, 2H, Ar-H), 7.90 (d, 2H, Ar-H), 7.57 (d, 2H, Ar-H), 7.51
(t, 2H, Ar-H), 7.42 (t, 2H, Ar-H), 7.17 (m, 2H, Ar-H), 6.88 (t, 2H,
Ar-H), 2.36 (s, 6H, CH3). Anal. Calc. for C28H20O2N2S2TiCl2: C,
56.11; H, 3.36; N, 4.67; Found: C, 56.27; H, 3.26; N, 4.56.
Zr[ON]2o-ClCl2 (3d)
This complex was prepared as described above for 3a, starting
from ZrCl4 (0.112 g, 0.5 mmol), and Ld (0.262 g, 1.0 mmol) in
THF (15 mL). Workup afforded 3d (0.178 g) as a light yellow
1
power in a yield of 52%. H NMR (CDCl3, 500 MHz): d 7.99
(d, 2H, Ar-H), 7.90 (d, 2H, Ar-H), 7.70 (d, 2H, Ar-H), 7.51 (m,
4H, Ar-H), 7.10 (t, 2H, Ar-H), 6.95 (t, 2H, Ar-H). Anal. Calc. for
C26H14O2N2S2ZrCl4: C, 45.69; H, 2.06; N, 4.10; Found: C, 45.60;
H, 2.08; N, 4.16.
This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 8838–8845 | 8843
©

Table 3 Summary of crystallographic data for La, 2b, 2c, 3b, 3c, 4b
La
2b
2c
3b
3c
4b
Formula
FW
T/K
C13H9NOS
227.27
293(2)
Monoclinic
P2(1)/c
12.432(5)
5.863(3)
15.623(7)
90
111.696(6)
90
1058.2(8)
4
C35H28Cl2N2O2S2Ti C36H36Cl2N2O2S2Ti C28H20Cl2N2O2S2Zr C36H36Cl2N2O2S2Zr C18H19Cl4NO2SZr
691.51
293(2)
Monoclinic
P2(1)/c
16.734(5)
12.974(4)
15.553(5)
90
106.260(5)
90
3241.5(18)
4
711.59
293(2)
Monoclinic
P2(1)/c
15.359(6)
16.453(7)
16.708(7)
90
93.492(6)
90
4215(3)
4
642.70
293(2)
Orthorhombic
Fdd2
28.606(8)
30.227(9)
13.172(4)
90
90
90
754.91
293(2)
Monoclinic
C2/c
20.663(10)
9.303(4)
17.749(8)
90
92.766(7)
90
546.42
293(2)
Triclinic
¯
P1
Crystal system
Space group
˚
a/A
7.223(4)
˚
b/A
12.381(7)
12.661(7)
90.178(7)
90.091(7)
106.687(7)
1084.5(11)
2
˚
c/A
a/◦
b/◦
g /◦
3
˚
Volume/A
11 390(6)
16
3408(3)
4
Z
D
calc/Mg m-3
1.427
0.279
472
1.417
0.593
1.121
0.458
1.499
0.749
1.471
0.637
1.673
1.110
Absorp coeff/mm-1
F(000)
1424
1480
5184
1552
548
Crystal size/mm
0.20 ¥ 0.10 ¥ 0.08 0.20 ¥ 0.12 ¥ 0.08 0.20 ¥ 0.07 ¥ 0.05
1.76–27.08
4851/2262
0.10 ¥ 0.10 ¥ 0.08
1.83–27.14
13 619/4422
[R(int) = 0.0554]
4422/1/337
0.12 ¥ 0.10 ¥ 0.10
1.97–27.01
7950/3654
[R(int) = 0.0568]
3654/0/208
0.12 ¥ 0.10 ¥ 0.10
1.61–25.01
4434/3696
[R(int) = 0.0558]
3696/0/246
2q range/◦
2.02–25.01
1.74–25.01
No. of reflns
13 151/5706
[R(int) = 0.1176]
5706/0/400
17 129/7405
[R(int) = 0.1048]
7405/0/414
collected/unique
No. of data/restraints/
params
[R(int) = 0.0652]
2262/2/149
Goodness of fit on F2
0.830
0.696
0.879
0.868
0.806
1.137
Final R indices [I > 2s(I)]a R1 = 0.0771
wR2 = 0.1996
R1 = 0.0501
R1 = 0.0698
wR2 = 0.1879
0.499 and -0.478
R1 = 0.0362
wR2 = 0.0802
0.342 and -0.278
R1 = 0.0435
wR2 = 0.0780
0.669 and -0.404
R1 = 0.1399
wR2 = 0.3891
2.152 and -0.898
wR2 = 0.0871
Largest diff peak and
1.334 and -0.223 0.365 and -0.315
-3
˚
hole/e A
ꢀ
ꢀ
ꢀ
a R1 = ꢀFo| - |Fcꢀ/ |Fo|; wR2 = [ w(|Fo2| - |Fc2|)2/ w|Fo2|2]1/2
.
Zr[ON]2p-ClCl2 (3e)
intensity data were performed with graphite-monochromated
˚
Mo Ka radiation (l = 0.71073 A). All data were collected at room
This complex was prepared as described above for 3a, starting
from ZrCl4 (0.112 g, 0.5 mmol), and Le (0.262 g, 1.0 mmol) in
THF (15 mL). Workup afforded 3e (0.196 g) as light yellow power
temperature using the w-scan technique. These structures were
solved by direct methods, using Fourier techniques, and refined
on F2 by a full-matrix least-squares method. There are disordered
solvents in the void of 2c, which can not be refined properly.
PLATON SQUEEZE12 process was used to omit these solvent
molecules and the structures were refined to convergence. All
the non-hydrogen atoms were refined anisotropically, and all the
hydrogen atoms were included but not refined. Crystallographic
data are summarized in Table 3.
1
in a yield of 58%. H NMR (CDCl3, 500 MHz): d 7.94 (d, 2H,
Ar-H), 7.67 (d, 2H, Ar-H), 7.52 (s, 2H, Ar-H), 7.45 (t, 2H, Ar-
H), 7.35–7.30 (m, 4H, Ar-H), 7.06 (d, 2H, Ar-H). Anal. Calc. for
C26H14O2N2S2ZrCl4: C, 45.68; H, 2.05; N, 4.10; Found: C, 45.59;
H, 2.11; N, 4.03.
Zr[ON]MeHCl4·THF(4b)
Ethylene polymerization
This complex was prepared as described above for 3a, starting
from ZrCl4 (0.112 g, 0.5 mmol), and Lb (0.131 g, 0.5 mmol) in THF
(15 mL). Workup afforded 4b as a yellow power. Recrystallization
of the product from CH2Cl2/hexane afforded 4b (0.189 g) as
colorless crystals in a yield of 68%. 1H NMR (CDCl3, 500 MHz):
d 14.10 (s, 1H, NH), 8.48 (d, 1H, Ar-H), 7.97 (d, 1H, Ar-H), 7.75
(t, 1H, Ar-H), 7.51–7.66 (m, 3H, Ar-H), 7.00 (t, 1H, Ar-H), 4.78
(s, 4H, THF), 2.85 (s, 3H, CH3), 2.14 (s, 4H, THF). Anal. Calc.
for C18H19O2NSZrCl4: C, 39.56; H, 3.50; N, 2.56; Found: C, 39.35;
H, 3.58; N, 2.46.
A 100 mL flask was equipped with an ethylene inlet, a magnetic
stirrer, and a vacuum line. The flask was filled with 30 mL of
freshly distilled toluene, MAO (10 wt% in toluene) was added,
and the flask was placed in a bath at the desired polymerization
temperature for 10 min. The polymerization reaction was started
by adding a toluene solution of the catalyst precursor (0.010 mmol)
with a syringe. Then the solvent toluene was added to make the
total volume of the solution 50 mL. The polymerization was
carried out for the desired time and then quenched with 3% HCl
in ethanol (250 mL). The precipitated polymer was filtered and
then dried overnight in a vacuum oven at 80 ◦C.
Single-crystal X-ray structure determination of complexes La, 2b,
2c, 3b, 3c and 4b†
For complexes 2b, 2c, 3b, 3c and 4b, a single-crystal suitable for
X-ray analysis was sealed into a glass capillary, all the intensity
data of the single crystal were collected on the CCD-Bruker
Smart APEX system. All determinations of the unit cell and
Acknowledgements
This work was supported by the National Science Foundation
of China (20531020, 20721063, 20771028), Shanghai Science and
8844 | Dalton Trans., 2009, 8838–8845
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The Royal Society of Chemistry 2009
©

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This journal is
The Royal Society of Chemistry 2009
Dalton Trans., 2009, 8838–8845 | 8845
©