Synthesis, structure, and olefin polymerization behavior of nickel complexes with carborane [S,C or [S,S Ligands

Article abstract of DOI:10.1021/om200516b

The o-carborane [S,C ligand 1 (1-(2′-(S)PPh₂)-o-carborane) was prepared by the reaction of a monophosphino o-carborane with elemental sulfur in the presence of Et₃N. Ligand 1 was lithiated with n-BuLi and then reacted with (Ph_3<

Full text of DOI:10.1021/om200516b

ARTICLE
pubs.acs.org/Organometallics
Synthesis, Structure, and Olefin Polymerization Behavior of
Nickel Complexes with Carborane [S,C] or [S,S] Ligands
Ping Hu,† Zi-Jian Yao,† Jian-Qiang Wang,‡ and Guo-Xin Jin*,†
†Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, Shanghai,
200433, People's Republic of China
‡Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204,
People's Republic of China
S Supporting Information
b
ABSTRACT: The o-carborane [S,C] ligand 1 (1-(20-(S)PPh2)-
o-carborane) was prepared by the reaction of a monophosphino
o-carborane with elemental sulfur in the presence of Et3N.
Ligand 1 was lithiated with n-BuLi and then reacted with
(Ph3P)Ni(Ph)Cl2, Ni(PPh3)2Cl2, and (DME)NiBr2, respec-
tively, to give the same mononuclear Ni complex [1-(20-(S)-
PPh2)-o-carborane]2Ni (2). Additionally, the lithium salt of
ligand 1 was treated with elemental sulfur and then reacted with
(Ph3P)Ni(Ph)Cl2, affording the mononuclear Ni complex [1-
S-(20-(S)PPh2)-o-carborane]2Ni (3). Ni complexes 2 and 3 were characterized by IR, 1H NMR, and 31P NMR spectroscopy and
elemental analysis. In addition, an X-ray structure analysis was performed on complex 2, where the o-carborane [S,C] ligand 1 was
found to coordinate in a bidentate mode. EXAFS spectroscopy was performed on complex 3 to confirm that the coordination
geometry was similar to that for complex 2. Two nickel complexes with carborane [S,C] or [S,S] ligands show good catalytic
activities for the addition polymerization of norbornene in the presence of methylaluminoxane (MAO) as cocatalyst. Catalytic
activities, molecular weights, and molecular weight distributions of polynorbornene (PNB) have been investigated under various
reaction conditions.
’ INTRODUCTION
center. Therefore, the design of such ligand systems containing
one functional group strongly bound to a late transition metal and
another coordinative labile group has been of considerable
interest.11 In materials science or chemical research, rational
design of new o-carborane-derived materials has attracted much
attention.12 Some reports on unusually stable C,N-,13 C,P-,14 N,S-,15
N,P-,16 and S,S-chelating17 o-carboranyl metal complexes seem
to imply that the rigid chelate conformation and the o-carboranyl
ligand backbone might be ideal for the stabilization of possible
metal intermediates in organometallic reactions. However, to the
best of our knowledge, there are few reports on using carborane
ligands to synthesize olefin polymerization catalysts.18,19 It was
therefore of interest to design a new family of nickel complexes
containing dissimilar donor atoms as catalysts for olefin polym-
erization. In this paper, we describe the preparation, structures,
and catalytic properties of norbornene addition polymerization
of the nickel complexes with carborane [S,C] or [S,S] ligands.
Norbornene polymerization has been widely used in industrial
production, due to the special optical and mechanical properties
of the polymers.1 The norbornene addition polymerization pro-
duct (PNB) displays a characteristic rigid random coil conforma-
tion, which shows restricted rotation about the main chain and
exhibits high thermal stability (Tg > 350 °C). In addition, it has
excellent dielectric properties, optical transparency, and unusual
transport properties.2 Therefore, it has been attractive to many
chemists to study the NB (norbornene) additionꢀpolymerization
using organometallic complexes as catalysts. Up to now, catalytic
systems based on titanium,3 zirconium,4 cobalt,5 chromium,6
nickel,7 palladium,8 and copper9 have been mainly investigated
for the additionꢀpolymerization of NB. Nickel complexes bear-
ing [N,O] and [N,N] ligands employed for norbornene polym-
erization exhibited especially high activity.7
In the pasttwodecades, transition-metal complexes with ligands
containing dissimilar donor atoms have been widely studied,
primarilyfor their applicationsin importanthomogeneouscatalytic
processes.10 The coordinative labile donor atom in such ligands is
capable of reversible dissociation from the metal center. Such
dynamic behavior will produce vacant coordination sites that allow
complexation of substrates during the catalytic cycle; at the same
time, the strong donor moiety remains connected to the metal
’ RESULTS AND DISCUSSION
The o-carborane [S,C] ligand 1 was obtained in good yield by
the reaction of a monophosphino o-carborane20 with 1 equiv of
Received: June 15, 2011
Published: August 25, 2011
r
2011 American Chemical Society
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dx.doi.org/10.1021/om200516b Organometallics 2011, 30, 4935–4940
|

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Scheme 1. Synthesis of Ligand 1
Scheme 2. Synthesis of Complex 2
Figure 1. ORTEP drawing of the molecular structure of complex 2. Hydrogen atoms are omitted for clarity. Selected distances (Å) and angles (deg):
Ni(1)ꢀC(1) = 1.989(3), Ni(1)ꢀS(1) = 2.2039(7), C(1)ꢀC(2) = 1.711(4), S(1)ꢀP(1) = 2.0024(11); C(1)ꢀNi(1)ꢀC(1A) = 180.00(16),
S(1A)ꢀNi(1)ꢀS(1) = 179.998(1), C(1)ꢀNi(1)ꢀS(1) = 93.26(9), C(1A)ꢀNi(1)ꢀS(1) = 86.74(9), C(2)ꢀP(1)ꢀS(1) = 105.12(10).
elemental sulfur in the presence of Et3N in refluxing THF
complex 2 suitable for single-crystal X-ray diffraction analysis
were obtained by slow diffusion of hexane into its CH2Cl2
solution. The molecular structure and selected bond distances
and angles are depicted in Figure 1. The molecular structure
reveals that the geometry at the nickel atom is distorted square
planar, two chelates [S,C] adopt a trans arrangement around the
nickel atom, and there is C2 symmetry. The C(2)ꢀP(1)ꢀS(1)
angle within the five-membered ring is smaller (105.12(10)°)
than the expected 108°. The C(1)ꢀNi(1)ꢀS(1) angle is slightly
larger (93.26(9)°) than a right angle. The angles C(1)ꢀNi(1)ꢀ
C(1A) (180.00(16)°) and S(1A)ꢀNi(1)ꢀS(1) (179.998(1)°)
are close to a straight angle, confirming that atoms C(1), Ni(1),
C(1A) and S(1A), Ni(1), S(1) are in a line, respectively. The
1
(Scheme 1). The ligand 1 was characterized by IR, H NMR,
and 31P NMR spectroscopy.
Ligand 1 was lithiated with n-BuLi and then reacted with
(Ph)3PNi(Ph)Cl2, Ni(PPh3)2Cl2, and (DME)NiBr2, respectively,
to give a product with the same structure (Scheme 2). The nickel
complex 2 is resolvable in common organic solvents, such as THF,
CH2Cl2, and toluene. The complex 2 is stable for a short time inair
due to the formation of a five-membered chelate ring.
Complex 2 has been fully characterized by IR, 1H NMR, and
31P NMR spectra and elemental analysis (see the Experimental
Section). The molecular structure of complex 2 was determined
by single-crystal X-ray diffraction studies. Dark red crystals of
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Scheme 3. Synthesis of Complex 3
Table 2. Addition Polymerization of Norbornene with 2 and
3 Activated by MAOa
entry complex Al/Ni ratio temp/°C activityb Mv Mw Mw/Mn
c
d
d
1
2
2
2
2
2
2
2
3
3
3
3
3
3
3
4000
6000
8000
10000
6000
6000
6000
4000
6000
8000
10000
8000
8000
8000
30
30
30
30
0
0.98
1.77
1.43
1.10
0.50
1.55
1.15
0.58
1.13
1.37
0.95
0.38
1.25
0.92
7.5
2
8.0 9.8
8.3
2.1
2.0
2.0
3
4
8.7
5
8.2
6
50
80
30
30
30
30
0
7.0 8.8
5.6
7
8
4.9
9
6.0
10
11
12
13
14
7.7 8.6
8.1
Figure 2. Ni K-edge XANES spectrum of 3. The inset gives the Fourier
transform of experimental data and fit for 3.
8.3
50
7.1
80
5.4
Table 1. Fit Parameters of Ni EXAFS Spectra for Complex 3
a Conditions: nickel complex, 0.8 μmol; solvent, chlorobenzene (total
Na
Rb
σ2 (10-3 Å2) c
ΔE0 (eV) d
volume 15 mL); norbornene, 1.88 g; reaction time, 30 min. b In units of
shell
106 g of PNB (mol of Ni)1ꢀ
h
ꢀ1. Mv (10ꢀ5 g molꢀ1) values were
c
NiꢀS
3.2 ( 0.2
2.19 ( 0.01
3.1 ( 0.8
5.9 ( 0.7
measured by the Ubbelohde calibrated viscosimeter technique. d Mw
(10ꢀ5 g molꢀ1) and Mw/Mn values were determined by GPC.
a Coordination number. b Distance between absorber and backscatterer atoms.
c DebyeꢀWaller factor. d Inner potential correction.
observed in other crystallographically characterized nickel(II)
complexes (average value of 2.10 Å).21
NiꢀS bond lengths of 2.2039(7) Å are typical for NiꢀS bonds.21
The NiꢀC distances (1.989(3) Å) in 2 are similar to those
observed in other crystallographically characterized nickel(II)
complexes.22
Preliminary experiments indicated that nickel complexes 2
and 3 can be used as catalysts for norbornene polymerization in
the presence of MAO as a cocatalyst. The polymerization results
are summarized in Table 2. It was revealed that MAO was
essential for the polymerization. In the complex 2/MAO catalytic
system, the optimal Al/Ni ratio was 6000. Increasing the Al/Ni
molar ratio from 4000 to 6000 led to higher activity in norbor-
nene polymerization and molecular weight (Mv) of the polymer
(entries 1ꢀ3, Table 2). However, when the Al/Ni ratio was
increased to 8000 or 10 000, the catalytic activity slightly
decreased (entries 4 and 5, Table 2). Additionally, the tempera-
ture was also crucial for the polymerization. We found that the
complex 2/MAO catalytic system showed the highest activity at
room temperature (30 °C). The complex 3/MAO catalytic
system can also polymerize norbornene with moderate activity
(entries 8ꢀ14, Table 2). The highest activity appears at 30 °C in
the optimal Al/Ni molar ratio (entry 10, Table 2). The drop in
activity at higher temperature seems to be indicative of complex
decomposition. The molecular weights (Mv) of the resulting
polymer are in the range of 490 000ꢀ870 000 with moderate
molecular weight distributions (Mw/Mn = 2).
Additionally, the lithium salt of ligand 1 was treated with
1 equiv of elemental sulfur and then reacted with (Ph3P)Ni-
(Ph)Cl2, affording the mononuclear Ni complex [1-S-(20-
(S)PPh2)-o-carborane]2Ni (3) (Scheme 3).
Complex 3 has been characterized by IR, 1H NMR, and 31
P
NMR spectra and elemental analysis. The local atomic environ-
ment and charge state of the metal center in complex 3 was
further confirmed by X-ray absorption spectroscopy, including
extended X-ray absorption fine structure (EXAFS) and X-ray
absorption near-edge structure (XANES) (Figure 2). The Four-
ier transform of the EXAFS spectrum (inset of Figure 2, bottom)
only comprises one main peak, which corresponds to the sulfur
donor atoms in the first coordination sphere of the metal ion.
The fitting results are summarized in Table 1. The fitting analysis
for the first shell confirms that the nickel ions in this complex
have the coordination number 3.2 ( 0.2, which is in the typical
range of a four-coordinate NiS4 environment. The average NiꢀS
distance is 2.19 Å. This bond lengths for 3 are similar to those
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The norbornene polymerization catalyzed by complexes 2 and
3 was the typical addition-vinyl type as confirmed by IR, 1H and
13C NMR, and GPC analyses of the obtained PNB. The reso-
nances of PNB appear at 0.9ꢀ3.03 ppm (m, maxima at 1.52, 1.87,
2.23, 2.59 ppm) in the 1H NMR, and the absence of bands in the
range 1680ꢀ1620 cmꢀ1 in the IR spectra indicated no double
bonds, which was different from the case for the polymers of
norbornene ring-opening metathesis polymerization.23 The 13C
NMR spectrum of PNB shows the main resonances at δ 30.0ꢀ
48.8 ppm (m, maxima at 32.43, 39.12, 48.39, 48.77 ppm),
attributed to the vinyl-addition polymer structure of polynorbor-
nene, bridge carbon, bridgehead carbon, and the backbone
carbon.24 All of the obtained PNB are soluble in chlorobenzene,
o-dichlorobenzene, and cyclohexane solvents, which indicates
low stereoregularity.25 Attempts to determine the glass transition
temperatre (Tg) of PNB failed, and DSC studies did not give an
endothermic signal upon heating to the decomposition tempera-
ture (above 450 °C).
warmed to room temperature and stirred overnight. The solvent was
removed under vacuum, leaving a dark red powder. Recrystallization of
the product from CH2Cl2/hexane afforded 2 as dark red crystals in a
yield of 71%. IR (KBr, cmꢀ1): 2567 m (BH), 1631 m, 1576 m, 1436 s
(Ph), 693 s (PdS). 1H NMR (400 MHz, CDCl3, ppm): δ 8.23ꢀ7.46
(m, 20 H, Ph H), 2.9ꢀ1.8 (br, 20H, carborane BH). 31P NMR
(162 MHz, CDCl3, H3PO4, 25 °C): δ 68.26 (s, PdS) ppm. Anal. Calcd
for C28H40B20NiP2S2: C, 43.25; H, 5.18. Found: C, 43.29; H, 5.21.
Method 2. To a stirred solution of 1 (90 mg, 0.25 mmol) in 15 mL of
THF, which was cooled to ꢀ78 °C, was added 1.6 M n-BuLi (0.16 mL,
0.25 mmol) via a syringe. The resulting pale yellow solution was stirred
at ꢀ78 °C for 1 h and then transferred through a cannula to a solution of
Ni(PPh3)2Cl2 (81.7 mg, 0.125 mmol) in 15 mL of THF. The resulting
dark red solution was warmed to room temperature and stirred over-
night. The solvent was removed under vacuum, leaving a dark red
powder. Recrystallization of the product from CH2Cl2/hexane afforded
2 as dark red crystals in a yield of 63%.
Method 3. To a stirred solution of 1 (90 mg, 0.25 mmol) in 15 mL of
THF, which was cooled to ꢀ78 °C, was added 1.6 M n-BuLi (0.16 mL,
0.25 mmol) via a syringe. The resulting pale yellow solution was stirred
at ꢀ78 °C for 1 h and then transferred through a cannula to a solution of
(DME)NiBr2 (38.2 mg, 0.125 mmol) in 15 mL of THF. The resulting
dark red solution was warmed to room temperature and stirred over-
night. The solvent was removed under vacuum, leaving a dark red
powder. Recrystallization of the product from CH2Cl2/hexane afforded
2 as dark red crystals in a yield of 80%.
’ CONCLUSION
We have synthesized two nickel complexes containing an o-
carboranyl S,C or S,S chelating ligand. The combination of X-ray
crystallographic and X-ray absorption spectroscopy confirms
the structures of these mononuclear nickel complexes. A pre-
liminary study shows that the new complexes 2 and 3 can be used
as catalysts for the addition polymerization of norbornene and
exhibited high activities in the presence of excess methylalumi-
noxane (MAO). Further investigations of the olefin polymeriza-
tion of such complexes and of the polymerization mechanism are
ongoing.
Synthesis of 3. To a stirred solution of 1 (90 mg, 0.25 mmol) in
15 mL of THF, which was cooled to ꢀ78 °C, was added 1.6 M n-BuLi
(0.16 mL, 0.25 mmol) via a syringe. The resulting pale yellow solution
was stirred at ꢀ78 °C for 1 h. Sulfur (8 mg, 0.25 mmol) was added after
the reaction mixture was warmed to room temperature. The resulting
yellow solution was transferred through a cannula to a solution of
trans-(Ph)3PNi(Ph)Cl2 (87 mg, 0.125 mmol) in 15 mL of THF. The
resulting dark red solution was warmed to room temperature and stirred
overnight. The solvent was removed under vacuum, leaving a dark red
powder. Recrystallization of the product from CH2Cl2/hexane afforded
3 as a dark red powder in a yield of 66%. IR (KBr, cmꢀ1): 2573 m (BH),
’ EXPERIMENTAL SECTION
General Procedures. All manipulations were performed using
standard Schlenk techniques. Dichloromethane was distilled from calcium
n
hydride. Commercial reagents, namely BuLi (1.6 M in hexene), Et3N,
1
1637 m, 1570 m, 1434 s (Ph), 691 s (PdS). H NMR (400 MHz,
sulfur, methylaluminoxane (MAO, 1.46 M in toluene), trans-(Ph3P)Ni-
(Ph)Cl2 and norbornene, were purchased from Acros Co. (DME)NiBr2,26
Ni(PPh3)2Cl2,27 and 1-(PPh2)-1,2-C2B10H1120 were prepared according to
the literature. Other solvents were used as received as technical grade
solvents. IR (KBr) spectra were recorded on a Nicolet FT-IR spectro-
photometer. 1H NMR measurements were obtained on a Bruker AC 400
spectrometer in CDCl3 solution. 31P NMR (162 MHz) spectra were
measured with a VAVCE DMX-400 spectrometer. Elemental analyses for
C and H were carried out on an Elementar III Vario EI analyzer.
Synthesis of 1. Sulfur (32 mg, 0.5 mmol) and 2 mL of triethylamine
were added to a solution of 1-(PPh2)-1,2-C2B10H11 (164.2 mg,
0.5 mmol) in THF (10 mL). The reaction mixture was stirred at reflux
temperature for 2 h and cooled to room temperature. Purification by
column chromatography used 1/3 ethyl acetate/petroleum ether. The
product was obtained as white needles in 85% yield. IR (KBr, cmꢀ1):
3052 m, 3023 s (carborane CꢀH), 2571 s (BH), 1642 w, 1584 m, 1436 s
(Ph), 690 s (PdS). 1H NMR (400 MHz, CDCl3, ppm): δ 8.25ꢀ8.19
(m, 5H, Ph H), δ 7.56ꢀ7.54 (m, 5H, Ph H), 4.66(s, 1H, carborane CH),
2.78ꢀ2.05 (br, 10H, carborane BH). 31P NMR (162 MHz, CDCl3,
H3PO4, 25 °C): δ 51.33 (s, PdS) ppm.
CDCl3, ppm): δ 7.71ꢀ7.45 (m, 20H, Ph H), 3.18ꢀ1.74 (br, 20H,
carborane BH). 31P NMR (162 MHz, CDCl3, H3PO4, 25 °C): δ 43.99
(s, PdS) ppm. Anal. Calcd for C28H40B20NiP2S4: C, 39.95; H, 4.79.
Found: C, 39.91; H, 4.80.
Single-Crystal X-ray Structure Determination of Com-
pound 2. Compound 2 did not show signs of decomposition during
X-ray data collection, which was carried out at room temperature, and
the intensity data of a single crystal were collected on a CCD-Bruker
Smart APEX system. All determinations of the unit cell and intensity
data were performed with graphite-monochromated Mo KR radiation
(λ = 0.710 73 Å). All data were collected at room temperature using the
ω-scan technique. The structures was solved by direct methods, using
Fouriertechniques, andrefinedon F2 by a full-matrix least-squares method.
All the calculations were carried out with the SHELXTL program.28 All
non-hydrogen atoms were refined anisotropically, and all the hydrogen
atoms were includedbut not refined. Crystallographic data and processing
parameters are given in ref 29.
XAFS Data Collection and Analysis. The X-ray absorption data
at the Ni K-edge of the sample were measured at room temperature in
transmission mode using ion chambers at beamline BL14W1 of the
Shanghai Synchrotron Radiation Facility (SSRF), People's Republic of
China. The station was operated with a Si (311) double-crystal mono-
chromator. During the measurement, the synchrotron was operated at
an energy of 3.5 GeV and a current between 150 and 210 mA. The
photon energy was calibrated with Ni metal foil. Data processing was
Synthesis of 2. Method 1. To a stirred solution of 1 (90 mg,
0.25 mmol) in 15 mL of THF, which was cooled to ꢀ78 °C, was added
1.6 M of n-BuLi (0.16 mL, 0.25 mmol) via a syringe. The resulting pale
yellow solution was stirred at ꢀ78 °C for 1 h and then transferred
through a cannula to a solution of trans-(Ph)3PNi(Ph)Cl (87 mg,
0.125 mmol) in 15 mL of THF. The resulting dark red solution was
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ARTICLE
performed using the program ATHENA.30 All fits to the EXAFS data
were performed using the program ARTEMIS.30
(7) (a) Gao, H.; Guo, W.; Bao, F.; Gui, G.; Zhang, J.; Zhu, F.; Wu, Q.
Organometallics 2004, 23, 6273–6280. (b) Wang, X.; Liu, S.; Jin, G.-X.
Organometallics 2004, 23, 6002–6007. (c) Huang, Y.-B.; Tang, G.-R.; Jin,
G.-X. Organometallics 2008, 27, 259–269. (d) Chen, F.-T.; Tang, G.-R.;
Jin, G.-X. J. Organomet. Chem. 2007, 692, 3435–3442.
(8) (a) Carlini, C.; Giaiacopi, S.; Marchetti, F.; Pinzino, C.; Galletti,
A. M. R.; Sbrana, G. Organometallics 2006, 25, 3659–3664. (b) Tang,
G.-R.; Lin, Y.-J.; Jin, G.-X. J. Organomet. Chem. 2007, 692, 4106–4112.
(c) Blank, F.; Scherer, H.; Ruiz, J.; Rodriguez, V.; Janiak, C. Dalton Trans.
2010, 39, 3609–3619. (d) Blank, F.; Vieth, J.; Ruiz, J.; Rodriguez, V.;
Janiak, C. J. Organomet. Chem. 2011, 696, 473–487. (e) Blank, F.;
Scherer, H.; Janiak, C. J. Mol. Catal. A: Chem. 2010, 330, 1–9.
(9) (a) Lassahn, P.-G.; Lozan, V.; Janiak, C. Dalton Trans. 2003,
927–935. (b) Berchtold, B.; Lozan, V.; Lassahn, P.-G.; Janiak, C.
J. Polym. Sci. A: Polym. Chem. 2002, 40, 3604–3614.
(10) (a) Takei, I.; Nishibayashi, Y.; Arikawa, Y.; Uemura, S.; Hidai,
M. Organometallics 1999, 18, 2271–2274. (b) Yang, H.; Alvarez-Gressier,
M.; Lugan, N.; Mathieu, R. Organometallics 1997, 16, 1401–1409.
(c) Yang, H.; Lugan, N.; Mathieu, R. Organometallics1997, 16, 2089–2095.
(11) (a) van Leeuwen, P. W. N. M.; Kamer, P. C. J.; Reek, J. N. H.;
Dierkes, P. Chem. Rev. 2000, 100, 2741. (b) McGuinness, D. S.; Cavell,
K. J. Organometallics 2000, 19, 741–748. (c) Chen, J. C. C.; Lin, I. J. B.
Organometallics 2000, 19, 5113–5121. (d) Gandelman, M.; Milstein, D.
Chem. Commun. 2000, 1603–1604.
(12) (a) Hawthorne, M. F.; Zink, J. I.; Skelton, J. M.; Bayer, M. J.;
Liu, C.; Livshits, E.; Baer, R.; Neuhauser, D. Science 2004, 303,
1849–1851. (b) Juhasz, M.; Hoffmann, S.; Stoyanov, E.; Kim, K.-C.;
Reed, C. A. Angew. Chem., Int. Ed. 2004, 43, 5352–5355.
(13) Lee, J. D.; Kim, S. J.; Yoo, D.; Ko, J.; Cho, S.; Kong, S. O.
Organometallics 2000, 19, 1695–1703.
Norbornene Polymerization. In a typical procedure, 0.8 μmol of
nickel complex 2 or 3 in 2.0 mL of chlorobenzene, 1.88 g of norbornene,
and 5 mL of fresh chlorobenzene were added into a special polymeri-
zation bottle (20 mL) with a strong stirrer under an Ar atmosphere. After
the mixture was kept at the desired temperature for 10 min, the desired
MAO (10%) was charged into the polymerization system via syr-
inge, and the reaction was started. Thirty minutes later, acidic ethanol
(20/1 v/v ethanol/concentrated HCl) was added to terminate the
reaction. The PNB was isolated, washed with ethanol, and dried at
80 °C for 48 h under vacuum. For all the polymerization procedures, the
total reaction volume was 15.0 mL, which can be achieved by variation
of chlorobenzene when necessary. IR (KBr, cmꢀ1): 2947 vs, 2869 vs,
1476 m, 1450 s, 1375 m, 1295 m, 1258 m, 1222 m, 1148 m, 1108 m, 1040 w,
1
943 w, 893 m, 805 m. H NMR (o-dichlorobenzene-d4, 500 MHz):
δ 0.9ꢀ3.03 ppm (m, maxima at 1.52, 1.87, 2.23, 2.59). 13C NMR
(o-dichlorobenzene-d4, 500 MHz): δ 30.0ꢀ48.8 ppm (m, maxima at
32.43, 39.12, 48.39, 48.77).
’ ASSOCIATED CONTENT
S
Supporting Information. A CIF file giving crystallo-
b
graphic data for complex 2, an ORTEP diagram of complex 2,
and a 13C NMR spectrum of the norbornene polymers formed by
the complex 2/MAO system. This material is available free of
charge via the Internet at http://pubs.acs.org.
’ AUTHOR INFORMATION
(14) Lee, T.; Lee, S. W.; Wang, H. G.; Ko, J.; Kang, S. O.; Ko, J.
Organometallics 2001, 20, 741–748.
(15) Chung, S. W.; Ko, J.; Park, K.; Cho, S.; Kang, S. O. Collect.
Czech. Chem. Commun. 1999, 64, 883–894.
Corresponding Author
*E-mail: gxjin@fudan.edu.cn;. Fax: (+86)-21-65643776.
(16) Lee, H. S.; Bae, J. Y.; Ko, J.; Kang, Y. S.; Kim, H. S.; Kim, S.-J.;
Chung, J.-H.; Kang, S. O. J. Organomet. Chem. 2000, 614ꢀ615, 83–91.
(17) (a) Jin, G.-X. Coord. Chem. Rev. 2004, 246, 587–602. (b) Yu,
X. Y.; Lu, S. X.; Jin, G.-X. Inorg. Chim. Acta 2004, 357, 361–366. (c) Yu,
X. Y.; Jin, G.-X.; Hu, N. H.; Weng, L. H. Organometallics 2002,
21, 5540–5548. (d) Jin, G.-X.; Wang, J.-Q.; Zhang, C.; Weng, L. H.;
Herberhold, M. Angew. Chem. 2005, 44, 259–262. (e) Wang, J.-Q.; Hou,
X. F.; Weng, L. H.; Jin, G.-X. Organometallics 2005, 24, 826–830.
(18) (a) Zi, G. F.; Li, H.-W.; Xie., Z. W. Organometallics 2002,
21, 3850–3855. (b) Wang, H. P.; Wang, Y. R.; Li., H.-W.; Xie., Z. W.
Organometallics 2001, 20, 5110–5118.
’ ACKNOWLEDGMENT
This work was supported by the Shanghai Science and
Technology Committee (Nos. 08DZ2270500, 08DJ1400103),
Shanghai Leading Academic Discipline Project (No. B108), and
the National Basic Research Program of China (Nos. 2009-
CB825300, 2010DFA41160).
’ DEDICATION
(19) (a) Wang, X.; Jin., G.-X. Organometallics 2004, 23, 6319–6322.
(b) Wang, X.; Weng, L. H.; Jin, G.-X. Chem. Eur. J. 2005, 11, 5758–5764.
(c) Wang, X.; Liu, S.; Jin., G.-X. Organometallics 2004, 23, 6002–6007.
(20) Clara, V.; Rajae, B.; Francesc, T.; Jaume, C. Inorg. Chem. 1995,
34, 3844–3845.
Dedicated to Herr Professor Dr. Max Herberhold on the
occasion of his 75th birthday
’ REFERENCES
(21) Huang, Y.-B.; Jia, W.-G.; Jin, G.-X. J. Organomet. Chem. 2009,
694, 86.
(1) (a) Janiak, C. Coord. Chem. Rev. 2006, 250, 66–94. (b) Janiak, C.;
Lassahn, P. G. J. Mol. Cata. A: Chem 2001, 166, 193–209. (c) Buchmeiser,
M. R. Chem. Rev. 2000, 100, 1565–1604. (d) Coates, G. W. Chem. Rev.
2000, 100, 1223ꢀ1252. (e) Blank, F; Janiak, C. Coord. Chem. Rev. 2009, 253,
827–861. (f) Janiak, C.; Lassahn, P.-G.; Lozan, V. Macromol. Symp. 2006,
236, 88–99.
(2) (a) Ittel, S. D.; Johnson, L. K.; Brookhart, M. Chem. Rev. 2000,
100, 1169–1203. (b) Gibson, V. C.; Spitzmesser, S. K. Chem. Rev. 2003,
103, 283–315.
(22) Wang, X.; Jin, G.-X. Organometallics 2004, 23, 6319–6322.
(23) (a) Sacchi, M. C.; Sonzogni, M.; Losio, S.; Forlin, F. Macromol.
Chem. Phys. 2001, 202, 2052–2058. (b) Barnes, D. A.; Benedikt, G. M.;
Goodall, B. L.; Huang, S. S. Macromolecules 2003, 36, 2623–2632.
(24) Huang, W. J.; Chang, F. C.; Chu, P. P. J. Polym. Sci. 2000,
38, 2554–2563. Mi, X.; Ma, Z.; Cui, N. J. Appl. Polym. Sci. 2003,
88, 3273–3278.
(25) Mast, C.; Krieger, M.; Dehnicke, K.; Greiner, A. Macromol.
Rapid Commun. 1999, 20, 232–235.
(3) Tritto, I.; Boggioni, L.; Sacchi, M. C.; Locatelli, P. J. Mol. Catal. A:
Chem. 1998, 133, 139–150.
(26) Kermagoret, A.; Braunstein, P. Organometallics 2008, 27, 88–99.
(27) Pei, L. X.; Liu, X. M.; Gao, H. Y.; Wu, Q. Appl. Organomet.
Chem. 2009, 23, 455–459.
(28) Sheldrick, G. M. SHELXL-97; Universit€at G€ottingen, G€ottingen,
Germany, 1997.
(4) Kaminsky, W.; Bark, A.; Arndt, M. Makromol. Chem. Macromol.
Symp. 1991, 47, 83–93.
(5) (a) Goodall, B. L.; McIntosh, L. H., III; Rhodes, L. F. Makromol.
Chem. Macromol. Symp. 1995, 89, 421–432. (b) Yasuda, H.; Nakayama,
Y.; Sato, Y. J. Organomet. Chem. 2004, 689, 744–750.
(6) Peuckert, U.; Heitz, W. Macromol. Rapid Commun. 1998, 19,
159–162.
(29) Crystal data for 2: C28H40B20NiP2S2, Mr = 777.57, monoclinic,
space group Pbca, a = 9.9525(8) Å, b = 18.2899(15) Å, c = 24.3850(19)
4939
dx.doi.org/10.1021/om200516b |Organometallics 2011, 30, 4935–4940

Organometallics
ARTICLE
Å, R = 90°, β = 90°, γ = 90°, V = 4438.8(6) Å3, Z = 4, Fcalcd = 1.164
g cmꢀ3, 30 302 total reflections, 5082 of which were independent (Rint
=
0.0334). The structure was refined to final R1 = 0.0663 (I > 2σ(I)),
wR2 = 0.1540 for all data, GOF = 1.240, and the maximum/minimum
residual electron density was 0.8110/0.7620 e Åꢀ3
.
(30) Ravel, B.; Newville, M. J. Synchrotron Radiat. 2005, 12,
537–541.
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