Synthesis and characterization of NiII and PdII complexes bearing N,N,S tridentate ligands and their catalytic properties for norbornene polymerization

Article abstract of DOI:10.1002/ejic.200800468

A series of new N,N,S tridentate nickel(II) complexes [(ArN = CHC ₆H₄NPh-2-SPh)NiBr] (Ar = 2,6-diisopropylphenyl, 1; Ar = 2,6-dimethylphenyl, 2; Ar = Ph, 3) and palladium(II) complexes [(ArN = CHC ₆H₄NPh-2-SPh)P

Full text of DOI:10.1002/ejic.200800468

FULL PAPER
DOI: 10.1002/ejic.200800468
Synthesis and Characterization of NiII and PdII Complexes Bearing N,N,S
Tridentate Ligands and Their Catalytic Properties for Norbornene
Polymerization
Jieming Long,[a] Haiyang Gao,*[a] Keming Song,[a] Fengshou Liu,[a] Hao Hu,[a]
Ling Zhang,[a] Fangming Zhu,[a,b] and Qing Wu*[a,b]
Keywords: Tridentate ligands / Nickel / Palladium / Norbornene polymerization
A series of new N,N,S tridentate nickel(II) complexes [(ArN
= CHC6H4NPh-2-SPh)NiBr] (Ar = 2,6-diisopropylphenyl, 1;
Ar = 2,6-dimethylphenyl, 2; Ar = Ph, 3) and palladium(II)
complexes [(ArN = CHC6H4NPh-2-SPh)PdCH3] (Ar = 2,6-di-
isopropylphenyl, 4; Ar = 2,6-dimethylphenyl, 5; Ar = Ph, 6)
were synthesized and characterized. X-ray diffraction analy-
ses of the single-crystal structures revealed that tridentate
complexes 1, 2, 4, 5, and 6 featured a distorted square-planar
coordination of the central metal. Compared to the bidentate
metal complexes bearing anilido–imine ligands, the N,N,S
tridentate metal complexes showed better stability. In the
presence of methylaluminoxane (MAO), nickel complexes 1–
3 showed moderate activity toward ethylene oligomerization
at atmosphere pressure, but the palladium complexes were
inactive. However, the nickel complexes exhibited high ac-
tivity up to 8.20ϫ106 g/(mol of Ni)h and palladium com-
plexes showed very high activity up to 2.68ϫ108 g/(mol of
Pd)h toward norbornene polymerization with MAO as cocat-
alyst. The obtained polynorbornenes are vinylic addition
polymers with high molecular weights.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2008)
search has been carried out to elucidate the influence of the
sterics of the ligands and the electronic effects of the ligands
on polymerization reactions.[1–14]
Introduction
During the last decade, transition-metal catalysts for ole-
fin polymerization have been extensively developed.[1]
Brookhart et al. reported that bulky α-diimine nickel(II)
and palladium(II) complexes exhibited high catalytic ac-
tivity for olefin polymerization.[2] Iron or cobalt complexes
bearing diimine–pyridine ligands were also reported as
highly active catalyst precursors for ethylene polymeriza-
tion.[3] (Salicylaldiminato)nickel complexes exhibited good
tolerance to functional groups and even remained active for
olefin polymerization in the presence of polar or protonic
solvents.[4–6] Coates[7] and Fujita[8] reported that high per-
formance olefin polymerization catalysts could be achieved
by the moderate electron-donating properties of the ligands.
For transition-metal olefin-polymerization catalysts, steric
and electronic effects of ligands play important roles in de-
termining the catalytic activity and polymer microstruc-
ture.[1,8,9] Therefore, the design and synthesis of transition-
metal olefin-polymerization catalysts mainly came from two
strategies: ligand sterics and electronic effects. Extensive re-
In addition, the sidearm approach had also proven to be
an efficient strategy for the design of organometallic cata-
lysts in olefin polymerization,[15–21] and the sidearm effect
of the extra donor had a strong influence on catalytic poly-
merization. In particular, metal complexes with N, P, O,
and S atoms in the sidearm were mainly reported. Chro-
mium,[15] titanium,[16,17] and nickel[18] complexes containing
salicylaldiminate ligands with pendant donors had higher
catalytic activities than the corresponding complexes with-
out sidearm donors. For the complexes containing relatively
hard nitrogen- and oxygen-coordinated atoms, a sidearm
containing the soft S or P donor atoms, for understandable
reasons, was usually introduced into the ligand backbone.
During the past few years, our groups has focused our
attention on nickel complexes bearing N,N ligands because
they can be easily modified in terms of steric and electronic
effects. Previously, from the ligand steric and electronic
points of view, nickel complexes chelating β-diimine, β-diket-
iminate, fluorinated β-diketiminate, and anilido–imine li-
gands were prepared, and their catalytic properties for ole-
fin polymerizations were studied.[22] Recently, interest in or-
ganometallic complexes chelating anilido–imine donor li-
gands has also increased dramatically. Yttrium,[23]
nickel,[22a–22e,24] copper,[25] aluminium,[26] and zinc[27] com-
plexes bearing anilido–imine ligands have also found appli-
[a] Institute of Polymer Science, School of Chemistry and Chemi-
cal Engineering, Sun Yat-Sen (Zhongshan) University,
Guangzhou 510275, China
Fax: +86-020-84114033
E-mail: ceswuq@mail.sysu.edu.cn,
gaohy@mail.sysu.edu.cn.
[b] PCFM Lab, OFCM Institute, Sun Yat-Sen (Zhongshan) Uni-
versity,
Guangzhou 510275, China
4296
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 4296–4305

NiII and PdII Complexes Bearing N,N,S Tridentate Ligands
cation in many areas of inorganic and organometallic
chemistry.
In this paper, modification of anilido–imine ligands by
the sidearm approach and the synthesis of the correspond-
ing N,N,S tridentate nickel(II) and palladium(II) complexes
is reported. Molecular structures of the complexes were also
characterized by X-ray single-crystal analyses. Additionally,
ethylene oligomerizations and norbornene (NB) polymeri-
zations catalyzed by these nickel and palladium complexes
after activation with methylaluminoxane (MAO) were also
investigated in detail.
Scheme 2. Synthesis of ligands L1–L3.
Results and Discussion
As described by the reported results, anilido–imino
nickel complexes existed as four-coordinate dimers in the
solid state, whereas they exist mainly as three-coordinate
monomers in solution.[22a] The introduction of a sidearm
group containing an S donor atom would lead to the for-
mation of more stable four-coordinate complexes
(Scheme 1). Therefore, nickel and palladium complexes
with various sterically hindered substituents were selected
for study.
Scheme 1.
Figure 1. Molecular structure of L2. The hydrogen atoms are omit-
ted for clarity. Selected bond lengths [Å] and angles [°]: S1–C1
1.782(2), S1–C7 1.785(2), C13–N1 1.383(3), N1–C12 1.410(2),
C19–C18 1.460(3), N2–C19 1.273(3), N2–C20 1.436(2), C1–S1–C7
102.03(9), C13–N1–C12 124.81(17), C19–N2–C20 117.25(17), N2–
C19–C18 125.04(18).
Three N,N,S tridentate ligands with various sterically
hindered substituents were synthesized. The synthetic route
for these tridentate ligands is shown in Scheme 2. Conden-
sation of 2-fluorobenzaldehyde with various anilines af-
forded imines 1a–c in high yields. The corresponding N,N,S
tridentate ligands were obtained by nucleophilic aromatic NMR spectra of complexes 4–6 exhibited methyl proton
displacement of fluorine in the imines by using PhS-2- signals at high field (δ = –0.420, –0.490 and –0.236 ppm,
C6H4NHLi. Pure products were obtained as yellow crystals respectively), which proved the existence of the Pd–Me
by recrystallization from ethanol in 44–57% yields. All of bonds.
these ligands were proved by 1H NMR and 13C NMR spec-
Crystals of nickel complexes 1 and 2 suitable for X-ray
troscopy and elemental analyses. A single crystal of L2 crystallography were grown from hexane/toluene solutions.
(Figure 1) growing in ethanol solution also assuredly con- Each of the crystal structures bears two crystallographically
firmed the ligand structure.
independent molecules, but there are no significant differ-
The synthetic route for these tridentate complexes is ences in the bond lengths and small deviations in the angles
shown in Scheme 3. After the ligands were deprotonated of the two molecules. Therefore, only one molecule of each
with n-butyllithium (1.0 equiv.) in toluene, (1,2-dimethoxye- of complexes 1 and 2 is discussed as a representative exam-
thane)nickel(II) bromide [(dme)NiBr2; 1.0 equiv.] was ple. Crystals of palladium complexes 4, 5, and 6 suitable for
added to the solution, and nickel complexes 1–3 were ob- X-ray crystallography were also grown from hexane/toluene
tained as dark-red solids in high yields. Similarly, when (1,5- solutions. ORTEP diagrams are given in Figures 2, 3, 4, 5,
cyclooctadiene)methylpalladium chloride [(cod)PdMeCl; and 6 along with selected bond lengths and bond angles,
1.0 equiv.] was added, palladium complexes 4–6 were ob- respectively.
tained as red solids in moderate yields. Nickel and palla-
Unlike the tetrahedral geometries of the anilido–imino
1
dium complexes 1–6 were fully characterized by H NMR nickel complexes,[22a] all of these tridentate complexes fea-
1
and IR spectroscopy, MS, and elemental analyses. The H ture a distorted square-planar coordination of the central
Eur. J. Inorg. Chem. 2008, 4296–4305
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4297

H.-Y. Gao, Q. Wu et al.
FULL PAPER
Figure 3. Molecular structure of complex 2. One of two crystallo-
graphically independent molecules. The hydrogen atoms are omit-
ted for clarity. Selected bond lengths [Å] and angles [°]: Ni1–N1
1.888(3), Ni1–N2 1.906(3), Ni1–S1 2.1783(10), Br1–Ni1 2.3364(5),
N1–C11 1.369(4), N2–C9 1.298(4), N2–Ni1–N1 92.30(12), N2–
Ni1–S1 175.81(8), N1–Ni1–S1 87.65(9), N2–Ni1–Br1 94.79(8), N1–
Ni1–Br1 172.34(9), S1–Ni1–Br1 85.49(3), C16–S1–Ni1 105.99(11),
C22–S1–Ni1 97.30(12), C22–S1–C16 104.31(16).
Scheme 3. Synthesis of complexes 1–6.
Figure 2. Molecular structure of complex 1. One of two crystallo-
graphically independent molecules. The hydrogen atoms are omit-
ted for clarity. Selected bond lengths [Å] and angles [°]: Ni1–N1
1.915(3), Ni1–N2 1.869(3), Ni1–S1 2.2013(11), Br1–Ni1 2.3241(6),
N1–C19 1.291(4), N2–C13 1.363(5), N2–Ni1–N1 91.09(13), N2–
Ni1–S1 87.27(10), N1–Ni1–S1 174.10(9), N2–Ni1–Br1 171.68(9),
N1–Ni1–Br1 95.34(9), S1–Ni1–Br1 86.85(3), C1–S1–Ni1
106.18(14), C12–S1–Ni1 97.62(14), C12–S1–C1 104.45(18).
Figure 4. Molecular structure of complex 4. The hydrogen atoms
are omitted for clarity. Selected bond lengths [Å] and angles [°]:
Pd1–N1 2.099(2), Pd1–N2 2.046(2), Pd1–S1 2.2433(7), Pd1–C32
2.056(3), N1–C13 1.370(4), N2–C19 1.294(3), N2–Pd1–N1
92.46(9), N2–Pd1–S1 178.38(6), N1–Pd1–S1 86.49(6), N2–Pd1–
C32 93.21(10), N1–Pd1–C32 174.33(10), S1–Pd1–C32 87.85(8),
C7–S1–Pd1 98.93(10), C1–S1–Pd1 106.34(9), C7–S1–C1
101.51(13).
metal due to the coordination of the S-donor sidearm. Each
nickel atom is surrounded by N, N, and S atoms and a
terminal Br ligand, whereas each palladium atom is sur-
rounded by N, N, and S atoms, and a terminal methyl li- viously, we reported that the anilido–imino nickel com-
gand. plexes are localized and have two nitrogen atoms bound to
Compared to ligand L2, imine bond (C=N) length of nickel with different bond lengths.[22a] In a comparison of
complex 2 becomes long, whereas the amine bond (C–N) the N–Ni bond lengths of the anilido–imino nickel com-
length becomes short due to the coordination of the N, N, plexes with those of the N,N,S nickel complexes, the
and S donor atoms to metal. The bond angles of Mt–S–C N(amine)–Ni bond lengths are nearly the same (ca. 1.88 Å),
and C–S–C (ca. 100°) of all complexes suggest that the S whereas the N(imine)–Ni bond lengths of the anilido–imino
atom is sp3 hybridized.[17] The five-membered S,N chelate nickel complexes are slightly longer than those of the N,N,S
ring is coplanar, and the metal atom lies out of the SCCN nickel complexes. In addition, the Br–Ni bond lengths of
plane 0.5029 Å for 1, 0.5404 Å for 2, 0.2255 Å for 4, the anilido–imino nickel complexes (ca. 2.45 Å) are also
0.2839 Å for 5, 0.5755 Å for 6. The six-membered N,N che- longer than those of the N,N,S nickel complexes (ca.
late ring has a boat conformation with the metal atom lying 2.33 Å). These results indicate that the N,N,S nickel com-
out of the NCCCN plane (slightly twisted coplanar). Pre- plexes are more stable than the anilido–imino nickel com-
4298
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 4296–4305

NiII and PdII Complexes Bearing N,N,S Tridentate Ligands
slightly more than 90° (Ͻ93°), whereas the bite angles (N–
Mt–S) are slightly less than 90° (Ͼ85°).
Ethylene oligomerizations were carried out with the
nickel and palladium complexes in the presence of MAO.
When nickel complexes 1–3 catalyzed ethylene oligomeriza-
tion at atmospheric pressure, no solid polymer was ob-
tained, and an amount of oligomeric products were formed
[activity: ca. 104 g/(mol of Ni)hatm)]. However, palladium
complexes 4–6 were inactive toward ethylene polymeriza-
tion or oligomerization. GC–MS analyses confirmed that
the oligomers obtained by the nickel catalysts mainly con-
tained dimers (C4) and trimers (C6); only a few tetramers
(C8) and higher oligomers were detected, which may be a
result of the lower steric hindrance of the complexes.
The nickel and palladium complexes bearing N,N,S li-
gands showed very high catalytic activities for norbornene
polymerization after activation with MAO. The polymeriza-
tion results are collected in Table 1. In general, the type of
metal had an important influence on the catalytic activity
for norbornene polymerization. For palladium catalysts, the
norbornene polymerization reaction was so rapid that the
polynorbornene with high molecular weight precipitated
and the stirring was stopped within less than 10 s under
the reaction conditions (Table 1, Run 4).[28a] Decreasing the
monomer concentration still resulted in precipitation of the
great amount of polymer within less than 30 s (Table 1,
Run 5). Therefore, at fixed MAO concentration, norbor-
nene polymerizations were carried out on the condition of
low norbornene and complex concentration (Table 1,
Run 6–8), and a high monomer conversion (66.5%) with
palladium catalysts was still obtained in 3 min. Under the
same conditions of low norbornene and complex concen-
tration (Table 1, Run 9), a low conversion (16.0%) with 1/
MAO was obtained in 1 h. This result suggests that the pal-
ladium complex exhibits a markedly higher catalytic ac-
tivity than the nickel analogues. The obtained polynorborn-
enes catalyzed by nickel catalysts can dissolve in common
organic solvents, but those obtained catalyzed by palladium
catalysts are insoluble in any solvents, which has been noted
before by Janiak and other groups.[21,28] Moreover, steric
hindrance of the aryl substituent of the complexes also af-
fects their catalytic activities and the molecular weights of
the polynorbornene. The nickel and palladium complexes
with bulky aryl substituents showed higher activity toward
Figure 5. Molecular structure of complex 5. The hydrogen atoms
are omitted for clarity. Selected bond lengths [Å] and angles [°]:
Pd1–N1 2.040(3), Pd1–N2 2.090(3), Pd1–S1 2.2466(11), Pd1–C28
2.066(4), N1–C9 1.290(5), N2–C15 1.379(5), N2–Pd1–N1
92.30(13), N2–Pd1–S1 86.38(9), N1–Pd1–S1 175.96(9), N2–Pd1–
C28 174.48(14), N1–Pd1–C28 93.20(15), S1–Pd1–C28 88.16(12),
C22–S1–Pd1 102.41(12), C21–S1–Pd1 98.83(13), C21–S1–C22
101.90(18).
Figure 6. Molecular structure of complex 6. The hydrogen atoms
are omitted for clarity. Selected bond lengths [Å] and angles [°]:
Pd1–N1 2.076(4), Pd1–N2 2.031(4), Pd1–S1 2.2503(13), Pd1–C26
2.055(5), N1–C13 1.362(5), N2–C19 1.306(6), N2–Pd1–N1 norbornene polymerization and produced higher molecular
91.10(14), N2–Pd1–S1 175.53(10), N1–Pd1–S1 85.61(10), N2–Pd1–
C26 92.29(17), N1–Pd1–C26 176.28(15), S1–Pd1–C26 91.08(14),
tion conditions, 1 with 2,6-diisopropyl on N-aryl groups
C1–S1–Pd1 105.58(13), C7–S1–Pd1 97.41(15), C7–S1–C1 104.4(2).
weight polymers. For example, under the same polymeriza-
produced a polynorbornene with a molecular weight of
112.2ϫ104 g/mol in the highest activity 6.80ϫ106 g/(mol of
plexes due to the coordination of the S sidearm to the metal Ni)h, whereas 3 without substituents on the aryl groups
atom. In contrast to the nickel complexes, the N(amine)– produced a polynorbornene with a molecular weight of
Pd bond lengths of the palladium complexes are slightly 72.5ϫ104 g/mol in the relatively low activity 4.60ϫ106 g/
longer than the N(imine)–Pd bond lengths, and the Pd– (mol of Ni)h, which is in accord with the steric hindrance
CH3 bond lengths (ca. 2.06 Å) are shorter than Br–Ni bond order of the three nickel complexes (1 Ͼ 2 Ͼ 3). These
lengths of the nickel complexes. Despite the different metal results indicate that the bulky steric hindrance could stabi-
atoms and different steric effects of the N-aryl groups, the lize the active species and suppress the chain transfer reac-
two bite angles (N–Mt–N and N–Mt–S) of all the com- tion during the polymerization process. Similar results were
plexes are nearly same. The bite angles (N–Mt–N) are obtained with the palladium catalysts.
Eur. J. Inorg. Chem. 2008, 4296–4305
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4299

H.-Y. Gao, Q. Wu et al.
FULL PAPER
Table 1. Results of norbornene polymerization with Ni or Pd cata-
lysts.[a]
Table 2. Results of norbornene polymerization with 2/MAO.[a]
[c]
Run Al/Ni Tp [°C] NB [g] % Yield Activity[b] Mw
Mw/Mn
[g]
Run Complex
Al/Ni(Pd) % Yield Activity[f] Mw
Mw/Mn
1
2
3
4
5
6
7
8
2000
2000
2000
2000
0
1000
3000
4000
2000
2000
2000
0
4
4
4
4
4
4
4
4
2
3
5
39.0
40.8
36.5
29.8
0
34.5
38.3
35.5
20.8
32.4
40.8
6.24
6.52
5.84
4.76
0
5.52
6.12
5.68
1.68
3.88
8.20
168.4
141.5
104.6
93.6
–
141.8
–
131.9
–
3.01
2.68
2.49
2.47
–
3.55
–
3.09
–
1
2
3
1 (1 µmol)
2 (1 µmol)
3 (1 µmol)
2000
2000
2000
2000
2000
20000
20000
20000
20000
2000
42.5
36.5
28.8
70.0
84.0
66.5
59.0
56.5
16.0
13.0
12.1
6.80
5.84
4.60
–
201
266
236
226
3.2
112.2
104.6
72.5
–
–
–
–
–
–
2.48
2.49
2.59
–
–
–
–
–
–
–
25
50
75
25
25
25
25
25
25
25
4[b] 4 (1 µmol)
5[c]
4 (1 µmol)
6[d] 4 (0.1 µmol)
7[d] 5 (0.1 µmol)
8[d] 6 (0.1 µmol)
9
9[e]
10
11
1 (0.1 µmol)
AI-Pr (1 µmol)
AI-Me (1 µmol)
10
–
–
–
–
2.08
1.94
–
–
11[d]
2000
–
[a] Polymerization conditions: complex (1 µmol), NB (4 g), toluene
(20 mL), 15 min. [b] In units of 106 g PNB/(mol of Ni)h. [c] In units
of 104 g/mol. [d] 10 min.
[a] Polymerization conditions: 50 °C, NB (4 g), 15 min, toluene
(20 mL). [b] NB (4 g), Ͻ10 s. [c] NB (2 g), 30 s. [d] NB (2 g), 3 min.
[e] NB (2 g), 60 min. [f] In units of 106 g PNB/(mol of cat)h. [g] In
units of 104 g/mol.
For a comparison, the results of norbornene polymeriza-
tions with anilido–imino nickel complexes [(ArN
=
CHC6H4NAr)NiBr] (Ar = 2,6-diisopropylphenyl, AI-Pr; Ar
= 2,6-dimethylphenyl, AI-Me) were also listed in Table 1
(Runs 10 and 11). The N,N,S tridentate nickel complexes
were more active than the N,N bidentate nickel complexes
in the norbornene polymerization. The coordination of S
sidearm to nickel metal resulted in a more stable four-coor-
dinate catalytic species, which would enhance the catalytic
activity. In addition, palladium complexes 4–6 also showed
much higher activity for norbornene polymerization than
the dinuclear tridentate P,N,S palladium complexes re-
ported by Kersting and coworkers with MAO as a cocata-
lyst [8.7ϫ105 g/(mol of Pd)h].[21]
Figure 7. Influence of polymerization time on the polymerization
yield with 2/MAO. Polymerization conditions: Al/Ni ratio, 2000;
complex (1 µmol); NB (4 g); toluene (20 mL); 25 °C.
To further investigate the reaction parameters affecting
norbornene polymerization, complex 2 was typically inves-
tigated by changing the polymerization temperature, Al/Ni
ratio, and the monomer concentration (Table 2). The 2/ rough analogy to that in the cases of the 2/MAO system. As
MAO catalytic system showed high activities over a large shown in Figure 8, the polymerization temperature strongly
range of reaction temperature. With an increase in reaction influenced the catalytic activity. The catalytic activity in-
temperature, the activity of complex 2 increased and creased obviously with increasing reaction temperature and
reached a maximal value of 6.52ϫ106 g/(mol of Ni)h at reached a maximal value at 50 °C. Additionally, preliminary
25 °C, and then decreased gradually, whereas the molecular experiments indicated that these palladium complexes were
weights of the obtained polynorbornenes decreased uni- not able to catalyze norbornene polymerization without co-
formly. The activator MAO was essential to norbornene po- catalysts. As we all know, MAO alone is also inactive for
lymerization, but the effects of the Al/Ni ratio on catalytic norbornene polymerization.[29] The role of MAO in the
activity and molecular weight of the obtained polynorborn- metal-catalyzed polymerization processes mainly are
enes were not obvious with an increase in Al/Ni from 1000 cleanup of the impurity, activation of metal complex, and
to 4000. Increasing the monomer concentration at fixed stabilization of active species.[30] Therefore, it is necessary
other reaction conditions resulted in dramatic increase in to use an excess amount of MAO for good to high activities.
the polymerization rate and catalytic activity. Figure 7 With an increase in the Al/Pd ratio from 10000 to 25000,
shows the time dependence of the norbornene polymeriza- the catalytic activities for norbornene polymerization in-
tion with 2/MAO. Apparently, the polymer yield increased creased markedly and then increased slowly (Figure 9). Sim-
in this whole process with longer reaction time. No induc- ilar results were obtained with other palladium catalysts.[31]
tion period was observed in the polymerization process.
Additionally, under the conditions of very low monomer
This observation suggests that the active species can be concentration (0.04 g/mL), the time dependence of the nor-
formed rapidly at the initial stage of the reaction and are bornene polymerization with 5/MAO was investigated (Fig-
then stabilized for a period of time.
ure 10). Like that of the nickel catalyst, polymer yield in-
The influences of the polymerization temperature and creased with an increase in reaction time and no induction
Al/Pd ratio for the 4–6/MAO catalytic system were in a period was observed. Polymerization yield was up to 85%
4300
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 4296–4305

NiII and PdII Complexes Bearing N,N,S Tridentate Ligands
Figure 8. Influence of polymerization temperature on catalytic ac-
tivity for norbornene polymerization with 4, 5, and 6/MAO. Poly-
merization conditions: Al/Pd ratio, 20000; complex (0.1 µmol); NB
(2 g); toluene (20 mL); 3 min.
Figure 10. Influence of polymerization time on polymerization
yield with 5/MAO. Polymerization conditions: 50 °C; Al/Pd ratio,
20000; complex (0.1 µmol); NB (0.8 g); toluene (20 mL).
unsuccessful, and the DSC curves did not show an endo-
thermic signal upon heating the polymers up to the decom-
position temperature.
Figure 9. Influence of Al/Pd ratio on catalytic activity for the nor-
bornene polymerization with 4, 5, and 6/MAO. Polymerization
conditions: 50 °C, complex (0.1 µmol), NB (2 g), toluene (20 mL),
3 min.
Figure 11. FTIR spectra of polynorbornenes catalyzed by 2/MAO
(a) and 5/MAO (b).
within 10 min. This observation suggests that the palladium
active species can be formed rapidly at the initial stage of
the reaction and is stabilized for a period of time until the
majority of the monomer is consumed.
The obtained polymers catalyzed by 1–3/MAO could be
1
characterized by H NMR and IR spectroscopy and GPC
analyses, whereas those catalyzed by 4–6/MAO were char-
acterized by IR spectroscopy because of their insolubility.
All of the obtained polymers showed very similar IR spec-
tra (Figure 11), which prove the absence of a double bond
Figure 12. 1H NMR spectrum of polynorbornene catalyzed by
2/MAO.
1
at 1620–1680 cm–1, and the H NMR spectrum (Figure 12)
of the obtained polynorbornenes catalyzed by 2/MAO also
prove no any traces of double bond, ensuring all of the
obtained polymers catalyzed by nickel or palladium cata-
lysts are vinylic addition polynorbornenes.[22b,28,29] TGA
Conclusions
We successfully synthesized and characterized N,N,S tri-
studies indicated that the obtained polymers were stable up dentate ligands and the corresponding nickel and palladium
to 450 °C under an atmosphere of nitrogen. The determi- complexes by modifying an anilido–imine ligand from a
nation of the glass transition temperature (Tg) of vinyl poly- sidearm approach. These complexes have a distorted
norbornenes is difficult, because the Tg of vinyl homopoly- square-planar coordination of the central metal. In the
mers is apparently close to the temperature.[22b] Attempts presence of MAO, nickel complexes 1–3 show moderate ac-
to measure Tg of polynorbornene from DSC curves was tivity for ethylene oligomerization, but the palladium com-
Eur. J. Inorg. Chem. 2008, 4296–4305
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4301

H.-Y. Gao, Q. Wu et al.
FULL PAPER
8.24 (dt, 1 H, ph), 7.52 (q, 1 H, ph), 7.30 (t, 1 H, ph), 7.24–7.09
(m, 4 H, ph), 2.99 (sp, 2 H, CH of iPr), 1.23 (d, 12 H, CH3) ppm.
13C NMR (75 MHz, CDCl3): δ = 164.3 (d, C–F), 155.5 (CH=N),
149.2, 137.4, 132.9, 127.6, 124.5, 124.2, 123.7, 123.0, 116.0, 28.0,
23.6 ppm. C19H22FN (283.38): calcd. C 80.53, H 7.82, N 4.94;
found C 80.54, H 7.67, N 4.73.
plexes are inactive. The obtained oligomers consist of di-
mers (C4) and trimers (C6) and a few tetramers (C8) and
higher oligomers. All of the nickel and palladium complexes
exhibit very high activity up to 8.20ϫ106 g/(mol of Ni)h
for nickel complexes and 2.68ϫ108 g/(mol of Pd)h for pal-
ladium complexes toward norbornene polymerizations. The
coordination of the S sidearm to nickel metal results in a
more stable four-coordinate catalytic species; thus, the
N,N,S tridentate nickel complexes have higher catalytic ac-
tivity than N,N bidentate anilido–imino nickel complexes.
All of the obtained polynorbornenes are vinylic addition
polymers with high molecular weights.
2-C6H4F(CH=NC6H3Me2-2,6) (1b): A solution of 2-fluorobenzal-
dehyde (9.4 g, 75.8 mmol) and 2,6-diimethylaniline (10.0 g,
82.5 mmol) in n-hexane (40 mL) was stirred for 2 h before MgSO4
was added. The mixture was then filtered, and the bright-yellow
solution was evaporated to dryness in vacuo to give a yellow oil.
The oil was distilled under reduced pressure, and a light-yellow
distillate at 170 °C/5 Torr was collected. Yield: 13.4 g (78%). 1H
NMR (300 MHz, CDCl3): δ = 8.58 (s, 1 H, CH=NAr), 8.29 (dt, 1
H, ph), 7.52 (q, 1 H, ph), 7.30 (t, 1 H, ph), 7.24–7.06 (m, 3 H, ph),
7.00 (t, 1 H, ph), 2.12 (s, 6 H, CH3) ppm. 13C NMR (75 MHz,
CDCl3): δ = 164.3 (d, C–F), 156.1 (CH=N), 151.0, 132.9, 127.9,
127.5, 126.9, 124.3, 123.8, 116.0, 18.4 ppm. C15H14FN (227.28):
calcd. C 79.27, H 6.21, N 6.16; found C 79.37, H 6.22, N 6.13.
Experimental Section
General: All manipulations of air- and moisture-sensitive com-
pounds were carried out under an atmosphere of nitrogen by using
standard Schlenk and vacuum-line techniques. Toluene, hexane,
and tetrahydrofuran (thf) were dried with sodium metal and dis-
tilled under nitrogen. [D]Chloroform was dried with CaH2. 2-Fluo-
robenzaldenyde (97%), 2,6-diisopropylaniline (92%), 2,6-dimeth-
ylniline(95%), 2-(phenoxythio)aniline (98%) and n-butyllithium
solution (2.86  in hexane) were bought from Aldrich Chemical
Co. and used without further purification. Norbornene (NB,
2-C6H4F(CH=NC6H5) (1c): A solution of 2-fluorobenzaldehyde
(9.4 g, 75.8 mmol) and aniline (8.0 g, 85.9 mmol) in n-hexane
(40 mL) was stirred for 2 h before MgSO4 was added. The mixture
was then filtered, and the bright-yellow solution was evaporated to
dryness in vacuo to give a yellow oil. The oil was distilled under
reduced pressure, and the light-yellow distillate at 120 °C/5 Torr
was collected. Yield: 11.5 g (76%). 1H NMR (300 MHz, CDCl3): δ
= 8.84 (s, 1 H, CH=NAr), 8.26 (dt, 1 H, ph), 7.54–7.12 (m, 8 H,
ph) ppm. 13C NMR (75 MHz, CDCl3): δ = 164.3 (d, C–F), 153.2
(CH=N) ppm. C13H10FN (199.22): calcd. C 78.37, H 5.06, N 7.03;
found C 78.16, H 5.15, N 7.03.
Acros) was purified by distillation over potassium and used as a
[32]
solution (0.4 g/mL) in toluene. The (dme)NiBr2
and (cod)-
PdMeCl[33] complexes were synthesized according to the literature.
Methylaluminoxane (MAO) was prepared by partial hydrolysis of
trimethylaluminium (TMA) in toluene at 0–60 °C with Al2(SO4)3·
18H2O as the water source. The initial H2O/Al molar ratio was 1.3.
Other commercially available reagents were purchased and used
without purification. Elemental analyses were performed with a
Vario EL micro analyzer. Mass spectra were measured with an LC–
Ligand L1: A solution of n-butyllithium (2.86  in hexane, 9.3 mL,
26.6 mmol) was added slowly to a solution of 2-(phenylthio)aniline
(5.33 g, 26.5 mmol) in thf (40 mL) at –78 °C, and the reaction mix-
ture was warmed to room temperature and stirred overnight. This
1
pale suspension was added to
a
solution of 1a [2-
MS instrument by using electro spray ionization (ESI). H NMR
and 13C NMR spectra were recorded with an INOVA 300 MHz
instrument at room temperature in CDCl3 or C6D6 solution for
ligands and complexes (with TMS as internal standard), and o-
dichlorobenzene solution for polymers (by using solvent as internal
standard). IR spectra were recorded with a Nicolet NEXUS-670
spectrometer. Mn, Mw, and Mw/Mn values of obtained polymers
were determined by using a Waters Alliance GPC 2000 series at
135 °C (by using polystyrene calibration, 1,2,4-trichlorobenzene as
the solvent at a flow rate of 1.0 mL/min). The GC–MS data were
recorded with a Finnigan Voyager GC-8000 TOP series GC-MS
system with DB-5MS GC column and the GC spectra were re-
corded with Varian CP3800 series GC system with a HP-5MS GC
column. Differential scanning calorimetry (DSC) analysis was con-
ducted with a Perkin–Elmer DCS-7 system. The DSC curves were
recorded at a heating rate of 10 °C/min. The cooling rate was 10 °C/
min. TGA data were collected with a TG-290C thermal analysis
system instrument under a nitrogen atmosphere up to 600 °C at
heating rate of 10 °C/min.
C6H4F(CH=NC6H3iPr2-2,6); 7.51 g, 26.5 mmol) in thf (20 mL) at
room temperature. After stirring for 12 h, the reaction was
quenched with H2O (20 mL) and extracted with n-hexane. The or-
ganic phase was evaporated to dryness in vacuo to give the crude
product as a yellow oil. Pure product was obtained as yellow crys-
tals by recrystallization from ethanol. Yield: 6.33 g (51%). 1H
NMR (300 MHz, CDCl3): δ = 11.06 (s, 1 H, N–H), 8.25 (s, 1 H,
CH=N), 7.58 (d, 1 H, Ar–H), 7.35 (d, 1 H, Ar–H), 7.30–7.05 (m,
12 H, Ar–H), 6.98 (t, 1 H, Ar–H), 6.82 (t, 1 H, Ar–H), 3.05 (sp, 2
H, CH of iPr), 1.13 (d, 12 H, CH3) ppm. 13C NMR (75 MHz,
CDCl3): δ = 164.8, 148.6, 145.8, 141.0, 138.1, 135.0, 134.5, 133.4,
131.6, 130.5, 128.8, 128.6, 128.0, 126.6, 124.2, 123.8, 122.8, 122.4,
119.0, 117.6, 113.4, 28.0, 23.7 ppm. C31H32N2S (464.66): calcd. C
80.13, H 6.94, N 6.03; found C 80.30, H 7.18, N 6.00.
Ligand L2: A similar procedure to that used for the preparation of
L1 was employed. 2-(Phenoxythio)aniline (4.20 g, 20.9 mmol), n-
butyllithium (2.86  in hexane, 7.3 mL, 20.9 mmol), and 1b (4.75 g,
20.9 mmol). Yield: 4.86 g (57%). 1H NMR (300 MHz, CDCl3): δ
= 11.17 (s, 1 H, N–H), 8.25 (s, 1 H, CH=N), 7.68, (d, 1 H, Ar–H),
7.25–7.44 (m, 5 H, Ar–H), 6.96–7.10 (m, 9 H, Ar–H), 6.86 (t, 1 H,
Ar–H), 2.12 (s, 6 H, CH3) ppm. 13C NMR (75 MHz, CDCl3): δ =
164.9, 150.4, 145.3, 142.0, 135.5, 135.0, 134.4, 131.5, 128.7, 127.8,
127.6, 126.3, 125.9, 123.6, 123.4, 1216, 119.3, 117.7, 113.6,
18.6 ppm. C27H24N2S (408.56): calcd. C 79.37, H 5.92, N 6.86;
found C 79.21, H 6.15, N 6.64.
2-C6H4F(CH=NC6H3iPr2-2,6) (1a): A solution of 2-fluorobenzal-
dehyde (11.7 g, 94.4 mmol) and 2,6-diisopropylaniline (17.6 g,
99.4 mmol) in n-hexane (40 mL) was stirred for 2 h before MgSO4
was added. The mixture was then filtered and washed with n-hex-
ane. The bright-yellow solution was concentrated to ca. 30 mL and
then cooled to –10 °C overnight to give large yellow crystals
(13.5 g). The filtrate was condensed to lower volume and cooled to
–10 °C to give additional pure crystals (4.2 g). Total yield: 17.7 g
Ligand L3: A similar procedure to that used for the preparation of
L1 was employed. 2-(Phenoxythio)aniline (7.71 g, 38.3 mmol), n-
1
(66%). H NMR (300 MHz, CDCl3): δ = 8.53 (s, 1 H, CH=NAr),
4302
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 4296–4305

NiII and PdII Complexes Bearing N,N,S Tridentate Ligands
butyllithium (2.86  in hexane, 13.4 mL, 38.3 mmol), and 1c
C27H23BrN2NiS (546.15): calcd. C 59.38, H 4.24, N 5.13; found C
(7.63 g, 38.3 mmol). Yield: 6.36 g (44%). 1H NMR (300 MHz, 59.65, H 4.39, N 4.80.
CDCl3): δ = 11.395 (s, 1 H, N–H), 8.52 (s, 1 H, CH=N), 7.60 (d,
Complex 3: A similar procedure to that used for the preparation
1 H, Ar–H), 7.28–6.85 (m, 16 H, Ar–H), 6.81 (t, 1 H, Ar–H) ppm.
13C NMR (75 MHz, CDCl3): δ = 161.5, 153.2, 150.6, 145.0, 142.0,
134.6, 132.3, 131.4, 130.9, 129.3, 128.8, 126.4, 126.1, 125.7, 123.2,
121.2, 121.0, 119.7, 117.8, 113.4 ppm. C25H20N2S (380.50): calcd.
C 78.91, H 5.30, N 7.36; found C 78.82, H 5.63, N 7.46.
of complex 1 was employed. L3 (0.97 g, 2.5 mmol), n-butyllithium
(2.86  in hexane, 0.89 mL, 2.55 mmol), and (dme)NiBr2 (0.86 g).
Yield: 0.87 g (65.9%). MS (ESI): m/z = 437, 438, 439, 440, 441, 442
(isotope, [M – Br]+). 1H NMR (300 MHz, C6D6): δ = 7.80–7.51
(m, 3 H, CH=N, Ar–H overlap); 7.50–6.46 (m, 16 H, Ar–H) ppm.
IR (KBr): ν = 1612, 1579, 1523, 1448, 1318, 1219, 1181, 1158, 1123,
˜
Complex 1: To a solution of compound L1 (1.05 g, 2.3 mmol) in
dried toluene (30 mL) at –78 °C was added n-butyllithium (2.86 
in hexane, 0.8 mL, 2.3 mmol) dropwise over a 10 min period. The
mixture was warmed to room temperature and stirred overnight.
(dme)NiBr2 (0.75 g) was added at room temperature, and the re-
sulting mixture was stirred overnight and filtered. The solid was
washed with toluene (3ϫ10 mL). The combined organic filtrates
were concentrated under reduce pressure to ca. 3 mL, and then dry
hexane (50 mL) was added. After the mixture was stirred for
30 min, filtration of the mixture gave complex 1 as a dark-red solid
in 89% yield (1.23 g). MS (ESI): m/z = 521, 522, 523, 524, 525
(isotope, [M – Br]+). 1H NMR (300 MHz, C6D6): δ = 7.82–7.68
(m, 2 H, CH=N, Ar–H overlap), 7.63 (d, 1 H, Ar–H), 7.23–7.05
(m, 3 H, Ar–H), 6.99–6.78 (m, 7 H, Ar–H), 6.73 (t, 1 H, Ar–H),
6.50 (t, 1 H, Ar–H), 6.30 (t, 1 H, Ar–H), 2.62–0.64 [m, 14 H,
1027, 746, 691 cm–1. C25H19BrN2NiS (518.09): calcd. C 57.96, H
3.70, N 5.41; found C 57.56, H 3.98, N 5.30.
Complex 4: To a solution of compound L1 (0.52 g, 1.12 mmol) in
dried toluene (30 mL) at –78 °C was added a n-butyllithium (2.86 
in hexane, 0.4 mL, 1.14 mmol) dropwise over a 10 min period. The
mixture was warmed to room temperature and stirred overnight.
(cod)PdMeCl (0.30 g) in dichloromethane (10 mL) was added at
room temperature. The resulting mixture was stirred overnight and
filtered. The solid was washed with toluene (3ϫ10 mL). The com-
bined organic filtrates were concentrated under reduce pressure,
and then dry hexane (5 mL) was added. After the mixture was
stirred for 30 min, the filtration of the mixture gave complex 4 as
a red powder in 62% yield (0.41 g). MS (ESI): m/z = 583, 584, 585,
586, 587, 588, 589, 590 [isotope, M+]; 566, 567, 568, 569, 570, 571,
572, 573, 574 [isotope, (M – CH3)+]. 1H NMR (300 MHz, CDCl3):
δ = 7.82–7.71 (m, 3 H, CH=N, Ar–H overlap), 7.61–7.51 (m, 2 H,
Ar–H), 7.29–7.23 (m, 3 H, Ar–H), 7.21–7.07 (m, 7 H, Ar–H), 6.59
(t, 1 H, Ar–H), 6.50 (t, 1 H, Ar–H), 3.36 (sp, 2 H, CH of iPr),
1.22–1.05 (m, 12 H, CH3), –0.42 (s, 3 H, Pd–CH3) ppm. IR (KBr):
CH(CH ) , overlap] ppm. IR (KBr): ν = 1606, 1579, 1533, 1437,
˜
3 2
1322, 1214, 1159, 1124, 1039, 745, 685 cm–1. C31H31BrN2NiS
(602.25): calcd. C 61.82, H 5.19, N 4.65; found C 61.59, H 5.45, N
4.60.
Complex 2: A similar procedure to that used for the preparation
of complex 1 was employed. L2 (0.82 g, 2.0 mmol), n-butyllithium
(2.86  in hexane, 0.7 mL, 2.0 mmol), (dme)NiBr2 (0.69 g). Yield:
1.03 g (91%). MS (ESI): m/z = 465, 466, 467, 468, 469, 470 (isotope,
[M – Br]+). 1H NMR (300 MHz, C6D6): δ = 7.75–7.62 (m, 2 H,
ν = 1602, 1582, 1525, 1473, 1447, 1443, 1332, 1202, 1028, 932, 837,
˜
742, 687 cm–1. C32H34N2PdS (585.11): calcd. C 65.69, H 5.86, N
4.79; found C 65.80, H 5.95, N 4.69.
Complex 5: A similar procedure to that used for the preparation of
CH=N, Ar–H overlap), 7.55 (d, 1 H, Ar–H), 7.23 (d, 1 H, Ar–H), complex 4 was employed. L2 (0.44 g, 1.07 mmol), n-butyllithium
7.04–6.60 (m, 10 H, Ar–H), 6.53–6.36 (m, 2 H, Ar–H), 6.26 (t, 1 (2.86  in hexane, 0.38 mL, 1.08 mmol), and (cod)PdMeCl (0.28 g).
H, Ar–H), 3.75–1.64 (m, 6 H, CH , overlap) ppm. IR (KBr): ν Yield: 0.32 g (56%). MS (ESI): m/z = 527, 528, 529, 530, 531, 532,
˜
3
= 1602, 1579, 1522, 1449, 1317, 1212, 1090, 1031, 752, 690 cm–1.
533, 534, 535 [isotope, M+]: 511, 512, 513, 514, 515, 516, 517, 518,
Table 3. Crystallographic date and refinement for L2 and complexes 1 and 2.
L2
1
2
Formula
Fw
C27H24N2S
408.54
C62H62Br2N4Ni2S2
1204.52
C54H46Br2N4Ni2S2
1092.31
T [K]
173(2)
0.71073
monoclinic
P21/n
173(2)
0.71073
monoclinic
P21/c
173(2)
0.71073
monoclinic
P21/c
λ(Mo-Kα) [Å]
Crystal system
Space group
a [Å]
10.125(2)
17.7626(16)
20.513(2)
b [Å]
c [Å]
8.0233(18)
26.920(6)
19.7558(17)
16.6084(15)
13.5870(15)
18.720(2)
α [°]
β [°]
90
98.449(4)
90
90
109.901(2)
114.605(2)
γ [°]
90
2163.1(8)
90
5480.1(8)
90
4743.7(9)
V [Å3]
Z
4
4
4
Dcalcd. [g/cm3]
Absorp. coeff. [mm–1]
F(000)
1.254
0.166
864
1.460
2.265
2480
1.529
2.608
2224
Crystal size [mm]
θ [°]
No. of date collected
No. of unique date
Goodness-of-fit on F2
Final R indexes [IϾ2σ(I)]
R indexes (all data)
0.48ϫ0.45ϫ0.30
1.53–27.10
10388
4665 Rint = 0.0354
1.053
R1 = 0.0510 wR2 = 0.1537
R1 = 0.0690, wR2 = 0.1707
0.44ϫ0.32ϫ0.28
1.22–27.09
28030
11937 Rint = 0.0519
1.002
R1 = 0.045 wR2 = 0.0943
R1 = 0.1012, wR2 = 0.1148
0.48ϫ0.42ϫ0.19
1.09–27.06
23990
10189 Rint = 0.0318
1.005
R1 = 0.0375 wR2 = 0.0973
R1 = 0.0659, wR2 = 0.1150
Eur. J. Inorg. Chem. 2008, 4296–4305
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4303

H.-Y. Gao, Q. Wu et al.
FULL PAPER
Table 4. Crystallographic date and refinement for complexes 4, 5, and 6.
4
5
6
Formula
Fw
C32H35N2PdS
586.08
C28H26N2PdS
528.97
C26H22N2PdS
500.92
T [K]
173(2)
173(2)
0.71073
monoclinic
P21/n
10.775(2)
11.479(2)
18.635(4)
173(2)
λ(Mo-Kα) [Å]
Crystal system
Space group
a [Å]
b [Å]
c [Å]
0.71073
triclinic
0.71073
triclinic
¯
¯
P1
P1
10.8867(17)
11.1754(17)
12.694(2)
10.156(3)
10.666(3)
11.179(4)
α [°]
β [°]
89.271(2)
76.702(2)
90
93.410(3)
102.810(5)
99.588(5)
γ [°]
64.493(2)
1349.9(4)
90
2300.9(8)
109.301(5)
1076.0(6)
V [Å3]
Z
2
4
2
Dcalcd. [g/cm3]
Absorp. coeff. [mm–1]
F(000)
1.442
0.788
606
1.527
0.916
1080
1.546
0.975
508
Crystal size [mm]
θ [°]
No. of date collected
No. of unique date
Goodness-of-fit on F2
Final R indexes [IϾ2σ(I)]
R indexes (all data)
0.48ϫ0.48ϫ0.36
1.66–27.10
11466
5809 Rint = 0.0203
1.074
R1 = 0.0302 wR2 = 0.0867
R1 = 0.0380, wR2 = 0.093
0.36ϫ0.25ϫ0.16
2.08–27.14
11280
5027 Rint = 0.0356
1.001
R1 = 0.0416 wR2 = 0.1094
R1 = 0.0615, wR2 = 0.1267
0.37ϫ0.32ϫ0.18
1.94–25.99
8076
4083 Rint = 0.0255
1.023
R1 = 0.0403 wR2 = 0.1328
R1 = 0.0496, wR2 = 0.1474
1
519 [isotope, (M – CH3)+]. H NMR (300 MHz, CDCl3): δ = 7.73
by syringe at the desired polymerization temperature. The resulting
(s, 1 H, CH=N), 7.71 (s, 1 H, Ar–H), 7.68 (s, 1 H, Ar–H) 7.59– mixture was stirred for a further 10 min, and the catalyst precursor
7.53 (m, 2 H, Ar–H), 7.31–7.26 (m, 3 H, Ar–H), 7.21–6.98 (m, 7 in toluene was injected by syringe. The polymerization was carried
H, Ar–H), 6.59 (t, 1 H, Ar–H), 6.50 (t, 1 H, Ar–H), 2.24 (s, 6 H,
out for the desired time and then quenched with concentrated HCl
CH ), –0.49 (s, 3 H, Pd–CH ) ppm. IR (KBr): ν = 1601, 1580, in ethanol (150 mL, HCl/ethanol, 5:95, v/v). The precipitated poly-
˜
3
3
1526, 1445, 1432, 1329, 1211, 1153, 1127, 1089, 1030, 837, 742,
mer was collected and washed with ethanol, and then dried over-
690 cm–1. C28H26N2PdS (529.00): calcd. C 63.57, H 4.95, N 5.30; night under vacuum at 50 °C.
found C 63.29, H 4.87, N 5.11.
X-ray Structure Determination: The crystals were mounted on a
Complex 6: A similar procedure to that used for the preparation of
complex 4 was employed. L3 (0.75 g, 1.97 mmol), n-butyllithium
(2.86  in hexane, 0.7 mL, 2.0 mmol), and (cod)PdMeCl (0.53 g).
Yield: 0.65 g (66%). MS (ESI): m/z = 1002 [2M]+; 524, 525, 526,
527, 528, 529, 530, 531 [isotope, [M + Na]+]; 499, 500, 501, 502,
503, 504, 505, 506 [isotope, [M]+]; 485, 486, 487, 488, 489, 490, 491
[isotope, (M – CH3)+]. 1H NMR (300 MHz, CDCl3): δ = 7.90 (s, 1
H, CH=N), 7.69–7.62 (m, 2 H, Ar–H), 7.59–7.52 (m, 2 H, Ar–H),
7.36–7.24 (m, 6 H, Ar–H), 7.21–7.01 (m, 6 H, Ar–H), 6.61 (t, 1 H,
Ar–H), 6.48 (t, 1 H, Ar–H), –0.24 (s, 3 H, Pd–CH3) ppm. IR (KBr):
glass fiber by using the oil drop scan method. Dates obtained with
the ω-2θ scan mode were collected with a Bruker SMART 1000
CCD diffractometer with graphite-monochromated Mo-Kα radia-
tion. The structures were solved by direct methods, whereas further
refinement with full-matrix least-squares on F2 was obtained with
the SHELXTL program package. All non-hydrogen atoms were re-
fined anistotropically. Hydrogen atoms were introduced in calcu-
lated positions with the displacement factor of the host carbon
atoms. Crystal data and processing parameters for L2 and com-
plexes 1, 2, 4, 5, and 6 are summarized in Tables 3 and 4.
ν = 1602, 1780, 1527, 1473, 1447, 1425, 1332, 1217, 1152, 1123,
˜
CCDC-673899 (for L2), -673900 (for 1), -673901 (for 2), -673902
(for 4), -673903 (for 5), and -673904 (for 6) contain the supplemen-
tary crystallographic data for this paper. These data can be ob-
tained free of charge from The Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data_request/cif.
1026, 933, 836, 740, 691 cm–1. C26H22N2PdS (500.95): calcd. C
62.34, H 4.43, N 5.59; found C 62.51, H 4.65, N 5.49.
Ethylene Oligomerization: The oligomerization under 1 atm of eth-
ylene was carried out in a typical procedure as follows. Appropriate
MAO solid was added into a 50-mL flask. The flask was back-
filled twice with ethylene, and then freshly distilled toluene (20 mL)
was added by syringe under an ethylene atmosphere at the desired
polymerization temperature. The resulting mixture was stirred for
a further 10 min, and the catalyst precursor in toluene was injected
by syringe. The reaction solution was vigorously stirred under
1 atm of ethylene for the desired time. The flask was cooled to
–10 °C and then quenched with concentrated HCl in ethanol
(10 mL, HCl/ethanol, 5:95, v/v). About 2 mL of organic solution
was dried with anhydrous Na2SO4 for GC–MS analysis.
Acknowledgments
Support from the National Natural Science foundation of China
(NSFC) (Projects 20734004, 20674097, and 20604034) and the Gu-
angdong Natural Science Foundation (NSFG) (Project 06300069
and 8251027501000018) are gratefully acknowledged. We thank Dr.
Qing Wang and Dr. Yu Liu for single-crystal X-ray technical assist-
ance.
Norbornene Polymerization: In a typical procedure, the appropriate
MAO solid was added into a 50-mL flask, and then freshly distilled
toluene and norbornene dissolved in toluene (0.4 g/mL) was added
[1] a) G. J. P. Britovsek, V. C. Gibson, D. F. Wass, Angew. Chem.
Int. Ed. 1999, 38, 428–447; b) S. D. Ittel, L. K. Johnson, M.
4304
www.eurjic.org
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2008, 4296–4305

NiII and PdII Complexes Bearing N,N,S Tridentate Ligands
Brookhart, Chem. Rev. 2000, 100, 1169–1203; c) G. W. Coates,
Chem. Rev. 2000, 100, 1223–1252; d) L. S. Boffa, B. M. Novak,
Chem. Rev. 2000, 100, 1479–1493; e) S. K. Mecking, Coord.
Chem. Rev. 2000, 203, 325–351; f) V. C. Gibson, S. K. Spitz-
messer, Chem. Rev. 2003, 103, 283–315; g) H. G. Alt, E. H.
Licht, A. I. Licht, K. J. Schneider, Coord. Chem. Rev. 2006,
250, 2–17; h) C. Janiak, Coord. Chem. Rev. 2006, 250, 66–94;
i) C. Janiak, F. Blank, Macromol. Symp. 2006, 236, 14–22.
[2] a) L. K. Johnson, C. M. Killian, M. Brookhart, J. Am. Chem.
Soc. 1995, 117, 6414–6415; b) L. K. Johnson, S. Mecking, M.
Brookhart, J. Am. Chem. Soc. 1996, 118, 267–268; c) C. M.
Killian, D. J. Tempel, L. K. Johnson, M. Brookhart, J. Am.
Chem. Soc. 1996, 118, 11664–11665; d) S. J. Mclain, J. Feld-
man, L. K. Johnson, M. Brookhart, Macromolecules 1998, 31,
6705–6707; e) P. Preishuber-Pflugl, M. Brookhart, Macromole-
cules 2002, 35, 6074–6076; f) A. C. Gottfried, M. Brookhart,
Macromolecules 2003, 36, 3085–3100.
[3] a) B. L. Small, M. Brookhart, A. M. A. Bennett, J. Am. Chem.
Soc. 1998, 120, 4049–4050; b) G. J. P. Britovsek, V. C. Gibson,
B. S. Kimberley, P. J. Maddox, S. J. McTavish, G. A. Solan,
A. J. P. White, D. J. Williams, Chem. Commun. 1998, 849–850.
[4] a) C. M. Wang, S. Friendrich, T. R. Younkin, R. T. Li, R. H.
Grubbs, D. A. Bansleben, M. W. Day, Organometallics 1998,
17, 3149–3151; b) T. R. Younkin, E. F. Connor, J. I. Hender-
son, S. K. Friendrich, R. H. Grubbs, D. A. Bansleben, Science
2000, 287, 460–462.
[5] a) X.-F. Li, Y.-S. Li, J. Polym. Sci., Part A: Polym. Chem. 2002,
40, 2680–2685; b) W.-H. Sun, H.-J. Yang, Z.-L. Li, Y. Li, Orga-
nometallics 2003, 22, 3678–3683.
[6] a) F. M. Bauers, S. Mecking, Angew. Chem. Int. Ed. 2001, 40,
3020–3022; b) F. M. Bauers, S. Mecking, Macromolecules 2001,
34, 1165–1171.
[7] a) J. Tian, P. D. Hustad, G. W. Coates, J. Am. Chem. Soc. 2001,
123, 5134–5135; b) P. D. Hustad, J. Tian, G. W. Coates, J. Am.
Chem. Soc. 2002, 124, 3614–3621; c) C. De Rosa, T. Circelli, F.
Auriemma, R. T. Mathers, G. W. Coates, Macromolecules 2004,
37, 9034–9047.
[8] a) H. Makio, N. Kashiwa, T. Fujita, Adv. Synth. Catal. 2002,
344, 477–493; b) Y. Yoshida, S. Matsui, T. Fujita, J. Organomet.
Chem. 2005, 690, 4382–4397; c) R. Furuyama, J. Saito, S. Ishii,
H. Makio, M. Mitani, H. Tanaka, M. Fujita, J. Organomet.
Chem. 2005, 690, 4398–4413.
[16]
[17]
[18]
D. C. H. Oakes, B. S. Kimberley, V. C. Gibson, D. J. Jones,
A. J. P. White, D. Williams, Chem. Commun. 2004, 2174–2175.
C. Wang, Z. Ma, X.-L. Sun, Y. Gao, Y.-H. Guo, Y. Tang, L.-
P. Shi, Organometallics 2006, 25, 3259–3266.
a) W.-F. Li, W.-H. Sun, G.-M. Chen, G.-Z. Wang, M.-D. Hu,
Q. Shen, Y. Zhang, Organometallics 2005, 24, 5925–5928; b) V.
Lozan, P. G. Lassahn, C. Zhang, B. Wu, C. Janiak, G. Rhein-
wald, H. Z. Lang, Naturforsch. B 2003, 58, 1152–1164.
J. Hou, W.-H. Sun, S. Zhang, H. Ma, Y. Deng, X. Lu, Organo-
metallics 2006, 25, 236–244.
E. Y. Tshuva, S. Groysman, I. Godbeg, M. Kol, Organometal-
lics 2002, 21, 662–670.
G. Siedle, P. G. Lassabn, V. Lozan, C. Janiak, B. Kersting, Dal-
ton Trans. 2007, 52–61.
a) H.-Y. Gao, W.-J. Guo, F. Bao, G.-Q. Gui, J.-K. Zhang, F.-
M. Zhu, Q. Wu, Organometallics 2004, 23, 6273–6280; b) H.-Y.
Gao, J.-K. Zhang, Y. Chen, F.-M. Zhu, Q. Wu, J. Mol. Catal. A
2005, 240, 178–185; c) H.-Y. Gao, Y. Chen, F.-M. Zhu, Q. Wu,
J. Polym. Sci., Part A: Polym. Chem. 2006, 44, 5237–5246; d)
H.-Y. Gao, Z.-F. Ke, L.-X. Pei, K.-M. Song, Q. Wu, Polymer
2007, 48, 7249–7254; e) H.-Y. Gao, L.-X. Pei, K.-M. Song, Q.
Wu, Eur. Polym. J. 2007, 43, 908–914; f) H.-Y. Gao, L.-X. Pei,
Y.-F. Li, J.-K. Zhang, Q. Wu, J. Mol. Catal. A 2008, 280, 81–
86; g) J.-K. Zhang, H.-Y. Gao, Z.-F. Ke, F. Bao, F.-M. Zhu, Q.
Wu, J. Mol. Catal. A 2005, 231, 27–34; h) J.-K. Zhang, Z.-F.
Ke, F. Bao, J.-M. Long, H.-Y. Gao, F.-M. Zhu, Q. Wu, J. Mol.
Catal. A 2006, 249, 31–39; i) Y.-F. Li, L. Jiang, L.-Y. Wang,
H.-Y. Gao, F.-M. Zhu, Q. Wu, Appl. Organomet. Chem. 2006,
20, 181–186; j) Y.-F. Li, L.-Y. Wang, H.-Y. Gao, F.-M. Zhu, Q.
Wu, Appl. Organomet. Chem. 2006, 20, 436–442.
P. G. Hayes, G. C. Welch, D. J. H. Emslie, C. L. Noack, W. E.
Piers, M. Parvez, Organometallics 2003, 22, 1577–1579.
H.-Y. Wang, X. Meng, G.-X. Jin, Dalton Trans. 2006, 2579–
2585.
a) E. C. Brown, N. W. Aboelella, A. M. Reynolds, G. Aullon,
S. Alvarez, W. B. Tolman, Inorg. Chem. 2004, 43, 3335–3337;
b) A. M. Reynolds, B. F. Gherman, C. J. Cramer, W. B. Tol-
man, Inorg. Chem. 2005, 44, 6989–6997.
X.-M. Liu, W. Gao, G.-H. Li, Y. Mu, H. Xia, Y. Ren, S.-H.
Feng, Organometallics 2005, 24, 1614–1619.
a) B. Y. Lee, H. Y. Kwon, S. Y. Lee, S. J. Na, S.-i. Han, H. Yun,
H. Lee, Y.-W. Park, J. Am. Chem. Soc. 2005, 127, 3031–3037;
b) T. Bok, H. Yun, B. Y. Lee, Inorg. Chem. 2006, 45, 4228–
4237.
a) X. Mi, Z. Ma, L.-Y. Wang, Y.-C. Ke, Y.-L. Hu, Macromol.
Chem. Phys. 2003, 204, 868–876; b) P. G. Lassahn, C. Janiak,
J. S. Oh, Macromol. Rapid Commun. 2002, 23, 16–20; c) H.
Liang, J.-Y. Liu, X.-F. Li, Y.-S. Li, Polyhedron 2004, 23, 1619–
1627; d) , P. G. Lassahn, V. Lozan, B. Wu, A. S. Weller, C.
Janiak, Dalton Trans. 2003, 4437–4450.
[19]
[20]
[21]
[22]
[23]
[24]
[25]
[26]
[27]
[9] a) C. Janiak, U. Versteeg, K. C. H. Lange, R. Weimann, E.
Hahn, J. Organomet. Chem. 1995, 501, 219–234; b) C. Jan-
iak Lange, K. C. H. U. Versteeg, D. Lentz, P. H. M. Budzelaar,
Chem. Ber. 1996, 129, 1517–1529; c) P. C. Mohring, N. J. Co-
ville, Coord. Chem. Rev. 2006, 250, 18–35; d) P. C. Mohring,
N. J. Coville, J. Organomet. Chem. 1994, 479, 1–29; e) P. C.
Mohring, N. Vlachakis, N. E. Grimmer, N. J. Coville, J. Or-
ganomet. Chem. 1994, 483, 159–166; f) P. C. Mohring, N. J. Co-
ville, J. Mol. Catal. 1992, 77, 41–50; g) C. Popeney, Z.-B. Guan,
Organometallics 2005, 24, 1145–1155.
[28]
[10] D. R. Moore, M. Cheng, E. B. Lobkovsky, G. W. Coates, An-
gew. Chem. Int. Ed. 2002, 41, 2599–2602.
[29]
a) X.-F. Li, Y.-S. Li, J. Polym. Sci., Part A: Polym. Chem. 2002,
40, 2680–2685; b) T. Hu, Y.-G. Li, Y.-S. Li, N.-H. Hu, J. Mol.
Catal. A 2006, 253, 155–164.
E. Y.-X. Chen, T. J. Marks, Chem. Rev. 2000, 100, 1391–1434.
C. Janiak, P. G. Lassahn, Polym. Bull. 2002, 47, 539–546.
L. G. L. Ward, Inorg. Synth. 1972, 13, 154–156.
R. E. Rulke, J. M. Ernsting, A. L. Spek, C. J. Elsevier, W. N. M.
Van Leeuwen, K. Vrieze, Inorg. Chem. 1993, 32, 5769–5778.
Received: May 10, 2008
[11] L. M. Alcazar-Roman, B. J. O’Keefe, M. A. Hillmyer, W. B.
Tolman, Dalton Trans. 2003, 3082–3087.
[30]
[31]
[32]
[33]
[12] G. Lanza, I. L. Fragala, T. J. Marks, J. Am. Chem. Soc. 2000,
122, 12764–12777.
[13] T. J. Demin, J. Am. Chem. Soc. 1997, 119, 2759–2760.
[14] M. Kamigaito, T. K. Lal, R. M. Waymouth, J. Polym. Sci.,
Part A: Polym. Chem. 2000, 38, 4649–4660.
[15] D. J. Jone, V. C. Gibson, S. Green, P. Maddox, Chem. Commun.
2002, 1038–1039.
Published Online: August 22, 2008
Eur. J. Inorg. Chem. 2008, 4296–4305
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4305