15Ethylene/Polar Monomer Copolymerization Using(Aza)ferrocenyl(di)imine Nickel(II) Catalysts
Makoto WATANABE
Takashi OKADA（アザ）フェロセニル（ジ）イミン Nickel（ＩＩ）触媒を用いるエチレン／
極性モノマー共重合
渡

辺

真

人

岡

田

隆

志

1,1 -Ferrocenyldiimine/NiBr2, 1,2-ferrocenyldiimine/NiBr2, and 2-azaferrocenylimine/NiBr2 were synthesizedand employed as catalysts for ethylene polymerization and ethylene/polar monomer copolymerization. 2Azaferrocenylimine/NiBr2 gave the highest activity for both ethylene polymerization and copolymerization of
ethylene with polar monomer such as acrylate among these complexes upon activation with PMAO. The cocatalyst components were also examined and a catalyst system consisting of 2-azaferrocenylimine/NiBr 2 andN,N-dimethylanilinium tetrakis(pentafluorophenyl)borate/ethylaluminum sesquichloride was found to be mostsuitable for the ethylene/acrylate copolymerization to afford an activity of 1.0 kg/Ni･mmol and an incorporationof 1.7 wt ％ polar comonomer in the obtained copolymer.

the highly pressurized (＞4MPa) conditions at elevated

1. Introduction

temperatures (＞ 80℃)4).

Late-transition-metal catalyzed olefin polymerization

Ferrocene is known as an electron-rich molecule due

1)

has attracted intense research interest in recent years ,to the electron donation from the iron(II) center 5).

since Brookhart and DuPont workers showed that

When ferrocene is combined with two imino groups tonickel(II) and palladium(II) α-diimine complexes canform ferrocenyldiimines as designed ligand, theirpolymerize ethylene into polymers with a branchedcomplexes with late transition metals can create an

microstructure2). The less oxophilic nature of late metalelectron-rich bidentate coordination environment that issystem may be suited for the copolymerization of

expected to increase poison resistance of transitionhydrocarbon olefins with polar monomers. Althoughmetals toward polar monomers. Furthermore,

there have been many reports regarding theazaferrocene itself can coordinate to transition metals

polymerization of polar monomers over transition metal

directly through its sp 2 -hybridized nitrogen 6) .

catalysts during the past decade3), the bulky α-diimine

Combining the azaferrocene molecule with an imino

ligating palladium catalyst is the only system with agroup creates a sterically rigid 5-membered bidentate

mechanism that gives random copolymerization ofgeometry that is expected to increase not only the

3b)

olefins with acrylate esters . Recently, the researchers

poison resistance but also copolymerization activity

in DuPont have reported α-diimine nickel(II) catalyzed

with polar monomers. We report here the synthesis ofcopolymerization of ethylene with acrylate esters under

1,1 -ferrocenyldiimine/NiBr2 (1), 1,2-ferrocenyldiimine（ 15 ）

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TOSOH Research ＆ Technology Review Vol.48（2004）

1

R
H
N
Ni

Fe

H

R

H
Fe

N

Br

N

Ph

Ph

Br
4

Fig.１

Br

Br

Ph

Ph

Ni

1

Ni

Fe

Ph

Br

N

N

N

Br

H

2

R

H

R

7

(Aza)ferrocenyl(di)imine Ni(II) complexes/NiBr2 (4), and 2-azaferrocenylimine/NiBr2 (7) (Fig.

44％ yield. On the other hand, 1,2-diformylferrocene1), and ethylene polymerization and ethylene/acrylates(5) 9) was synthesized by the lithiation of 2-

copolymerization using them7).

ferrocenecarboxaldehyde methoxymethylacetal
followed by acid hydrolysis. 1,2-Ferrocenyldiimines(6a,b) were easily prepared by reacting 5 with aniline

2. Results and Discussion

and 2-methylaniline in AcOH/EtOH. Formation of the［1］Synthesis of 1,1 -and 1,2-ferrocenyldiimine/corresponding nickel(II) complexs (4a and 4b) was

NiBr2

carried out with these diimines and (DME)NiBr2 in
93％ and 85％ yields, respectively. Synthetic routes are

1,1 -Disubstituted ferrocenes can be derived fromshown in Scheme 1.

the reaction of 1,1 -dilithioferrocene with electorophiles.
8)

Therefore, 1,1 -diformylferrocene (2) was prepared［2］Ethylene polymerization and ethylene/methyl

using N,N -dimethylformamide (DMF) as anelectorophile. Formation of 1,1 -ferrocenyldiimine (3)acrylate

copolymerization

was carried out with 2 and aniline in EtOH. The

ferrocenyldiimine/Ni(II) catalysts

using

1,2-

reaction of (DME)NiBr2 with 3 proceeded in CH2Cl2 at

Polymerization of ethylene was examined using 1

room temperature to afford the nickel(II) complex 1 inand 4 (50 μmol) at 1.0 MPa ethylene pressure upon

H

H
CHO

1)n -BuLi,
Me2N(CH2)2NMe2

Fe

N

N
(DME)NiBr2

anilineFe

2)DMF
3)H3O＋

Fe

EtOH

Ni

Fe

CH2Cl2

N

N

CHO
2

3

H

H

85％y

1

44％y

R
O
CHO
1)tert -BuLi,Et2O

O
Fe

Fe

2)DMF
3)H3O＋

MeO

CHO

5
R

H

H
Fe

N

H2N

R

H
N

H
Fe

R

N

72％y

(DME)NiBr2
CH2Cl2

cat.AcOH,EtOH
6a(R＝H)61％y；6b(R＝Me)75％y

R

N

Ni
Br

Br

4a(R＝H)93％y，4b(R＝Me)85％y

Scheme１Synthesis of 1,1' -ferrocenyldiimine/NiBr2 (1) and 1,2-ferrocenyldiimine/NiBr2 (4)（ 16 ）BrBr

東ソー研究・技術報告 第48巻（2004）17

activation with PMAO as co-catalysts (Al/Ni ratio ＝

The copolymerization of ethylene/methyl acrylate100) in toluene. Whereas the precatalyst 1 showed nowas conducted with 4a/PMAO catalyst and the results

polymerization activity, 4a gave polymerization productwere summarized in Table 1. Although the activity was(0.07 kg/Ni・mmol,h) as an oil having a molecularquite low, the analysis of 13C NMR spectrum (Fig. 3) ofweight (Mw) of 5.6 × 102 g/mol and a molecular weightthe obtained polymer implied that copolymerization

distribution of 1.6 by GPC. The GC analysis showed

proceeded from the chemical shifts of carbonylthat the product contained no oligomers of C 4 -C 40

groups2b) (δ＝ 172-176).

content. The catalysts consisting of α-Diimine( N Ph)/NiBr2 and MMAO are known to give oligomers［3］Synthesis of 2-azaferrocenylimine/NiBr2

10)with a Schulz-Flory distribution . This difference

As described above, we have found the 1,2-

would probably lie on the number of chelating rings

ferrocenyldiimines nickel(II) complex was capable of13

and the presence of the ferrocene moiety. The C NMR

building the ethylene/methyl acrylate sequence in the

spectrum of the obtained polymer showed that it was

obtained polymer. This finding encouraged us tohighly branched and had the sec -butyl group as afurther pursue the investigation of ethylene/acrylate

11)(Fig. 2). On

ester copolymerization. Because the rigid 5-membered

the other hand, 4b gave no polymer. As 4b was mixedchelation structure is considered to be critical not onlywith PMAO, a black precipitate was immediately

to improve catalytic activity but also to increase

formed, indicating the reduction of nickel(II) species bymolecular weights, we attempted to exploit

PMAO took place.

azaferrocenylimine nickel(II) complexes. The synthesis

branch on branch group (δ= 11.4, 19.2)

Table 1 Ethylene/methyl acrylate copolymerization using 1,2-ferrocenyldiimine/NiBr2 (4a)aruncatalyst

4a [mmol]

1
2

4a/PMAO
4a/PMAO

0.113
0.110

methyl acrylate[mL, mmol]
5.0, 55
15.0, 165

yield
activity
acrylate
Mw c Mw /Mn[g] [g/Ni･mmol] incorporation [wt%]b [×10−3]
1.0
1.8
2.08
18.4
18.6
1.0
1.9
1.60
14.5
24.8

a

Polymerization conditions: ethylene pressure; 1 MPa, 0.5 L of toluene, 24 h, Al/Ni ratio 100. temperature 25℃,
time 24 h. bDetermined by 1H NMR. cDetermined by GPC relative to polystyrene standards.

Fig.２

13

C NMR spectrum of obtained polyethylene（ 17 ）

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TOSOH Research ＆ Technology Review Vol.48（2004）

Fig.３

13

C NMR spectrum of obtained ethylene/methyl acrylate copolymer

of azaferrocenylimine/NiBr2 (7) was carried out by acarried out with anilines in AcOH/EtOH. Nickel(II)synthetic method similar to 1,2-ferrocenyldiimine/

complexes 7a and 7b were prepared from 10a,b andNiBr2 (4) (Scheme 2). Pentaphenylazaferrocene (8),(DME)NiBr2 in CH2Cl2. The Cp* derivative 7c was also

prepared from Ph5CpLi, FeCl2 and potassium pyrrolide

prepared similarly.

in one pot manner, underwent lithiathion by n-BuLi［4］Ethylene/acrylate ester copolymerization using

followed by formulation by DMF to afford 2-formyl

2-azaferrocenylimine/Ni(II) catalysts

azaferrocene 9 in 72％ yield. Formation of imines 10a
1

2

1

2

(R ＝ i -Pr, R ＝H) and 10b (R ＝Me, R ＝OMe) was

A highly active ethylene polymerization catalyzed by

1

R

Ph

N
Fe

1)n-BuLi,THF,−50℃
Ph

Ph

2)DMF
Ph 3)H2O

Ph

N
Fe

O

N
Fe

Substituted anilines
cat. AcOH, EtOH

Ph

Ph

2

R

H

H

Ph

Ph
Ph

Ph

Ph

N

Ph

Ph

Ph

8

9 72％y10a 89％y; b 95％y
Me(DME)NiBr2
CH2Cl2

Ph

N
Fe

N
Ni
Ph

Ph

N

N
Br

Br

Ph

Fe

Ph

7a 82％y

Ni
Ph

Br

Br

Ph

Ph

Ph

Ph

OMe

H

H

7b 97％y

H
N

N
Me

Fe

Me

Ni
Me

Br

Br

Me
Me

Scheme２7cSynthesis of 2-azaferrocenylimine/NiBr2 (7)（ 18 ）

東ソー研究・技術報告 第48巻（2004）

19

DAN・FABA exhibited approximately ten-times higher

azaferrocenylimine/NiBr2 was revealed upon activation
7)

with PMAO . The activity was as high as 7.0 kg/Ni・

activity (run 4). Halogenated alkylaluminums are

mmol,h at 1.0 MPa of ethylene pressure. The α-

thought to be suited for activating the nickel (II)diimine-nickel(II) catalyzed copolymerization of

precatalyst and suppressing the reduction of nickel(II)ethylene/2-phenoxyethyl acrylate was reported to takeactive species. When lithium tetrakis (pentafluoro-

place in the presence of a large excess ofphenyl)borate was used as an additive (20 equiv. totris(pentafluorophenyl)borane and tetrakis(penta-Ni)4), it gave a negative effect on the activity (run 5). On

H NMR

the other hand, although the complex 7b bearing an

characterization of the obtained copolymer and acrylate

electron-donating methoxy group on the N-aryl grouphomopolymer was shown in that literature. Therefore,

was less active than 7a, it led to higher incorporation of

we conducted the copolymerization of ethylene/2-

acrylate comonomer (run 6). When this catalyst system

phenoxyethyl acrylate catalyzed by 2-azaferrocenyl-

was heated to 100℃, the activity slightly decreased toimine/NiBr2 at 4 MPa of ethylene pressure (Table 2).

0.35 kg/Ni・mmol (run 7). A plausible explanation for

When PMAO was used as an activator for the nickel(II)the higher incorporation of acrylate comonomer would

complex 7a (Ni/Al ratio ＝ 1/100), the activity of 0.11

be the increased electron density around the nickel

kg/Ni・mmol was obtained at 25℃ (run 1), but it

center of 7b enaugh to attract an electron-poor acrylate.

decreased to 0.02 kg/Ni・mmol at 50℃ (run 2). One

The Cp* derivative 7c was extremely less active (run 8)

needs to take into consideration the fact thatas compared with 7a, although its incorporation ofunfavorable concomitant reduction of nickel(II) active

acrylate ester became more than doubled. Thus, thespecies competes especially at higher temperature.

pentaphenyl cyclopentadienyl moiety in the complexes

Therefore, the catalyst containing a borate component

was indispensable for the copolymerization of ethylene-

was examined. When trimethylaluminum wasacrylate esters.

4)

fluorophenyl)borate salt . Detailed

1

combined with N , N -dimethylanilinium tetrakis

Characterization of the incorporation of acrylate(pentafluorophenyl)borate(DAN・FABA)(Ni/B/Al

monomer was carried out by measuring 1 H NMR

ratio ＝ 1/5/100), the comparable activity (0.15

spectra of the obtained polymers. The typical spectrum

kg/Ni・ mmol) was obtained even at higherof a polymer from run 4 was shown in Fig. 4. The

temperatures (80℃, run 3). Surprisingly, the cocatalyst

chemical shift around 4.37 to 4.45 ppm was assigned toconsisting of ethylaluminum sesquichloride andthe phenoxyethyl moieties in the copolymer but theaTable 2 Ethylene/2-phenoxy acrylate copolymerization using 2-azaferrocenylimine/NiBr2 (7)run catalyste7temp. time
[μmol] [℃] [h]yieldactivitya. i.
b[g] [kg/Ni･mmol] [wt%]Mw c Mw /Mn Tm d
-4[℃]
[×10 ]ΔH[J/g]

7a/PMAO

22.1

25

30

2.62

0.11

1.7

2.9

3.7

57.7

28.1

2e 7a/PMAO

12.8

50

12

0.29

0.02

1.2

1.7

3.3

48.3

25.3

3f 7a/Ph(Me)2NH・B(C6F5)4 5.5/Me3Al4f 7a/Ph(Me)2NH・B(C6F5)4 5.7/Et3Al2Cl3f,g
5 7a/Ph(Me)2NH・B(C6F5)4 5.5/Et3Al2Cl3
6f 7b/Ph(Me)2NH・B(C6F5)4 10.0
/Et3Al2Cl3
7f 7b/Ph(Me)2NH・B(C6F5)4 5.0/Et3Al2Cl3f
8 7c/Ph(Me)2NH・B(C6F5)4 6.9/Et3Al2Cl3

80

20

0.72

0.15

0.7

1.9

3.7

40.0

80

10

5.73

1.00

1.7

2.2

3.1

80

10

2.99

0.54

0.9

2.0

3.3

80

10

4.51

0.45

2.1

1.4

3.7

100

10

1.75

0.35

2.5

0.9

3.5

50

10

0.03

0.004

5.7

0.2

2.6

30.9
74.8
44.8
83.7
42.0
85.0
33.2
81.0
35.0
69.5
55.3

1

a

55.5
56.3
62.7
53.1
75.0

Polymerization conditions: ethylene pressure; 4 MPa, 0.5 mL (2.86 mmol) of 2-phenoxyethyl acrylate, 30 mL of toluene.
Acrylate incorporation, determined by 1H NMR. cDetermined by GPC relative to polystyrene standards. dDetermined
by DSC. eAl/Ni ratio 100. fNi/B/Al ratio 1/5/100. g20 equiv. of Li・B(C6F5)4 to the Ni complex was added as additive.
b（ 19 ）

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TOSOH Research ＆ Technology Review Vol.48（2004）

Fig.４

13

C NMR spectrum of obtained ethylene/2-phenoxyethyl acrylate copolymer

peak due to acrylate homopolymer (δ＝ 4.31) were not4)

observed . All polymers obtained in Table 2 were1

consistently characterized by H NMR analysis as themethod is more practical on the economical point ofview because it needs only small amounts of highly
expensive borate cocatalyst.

expected copolymers.

4. Experimental
3. Conclusion［1］General

1,1 -Ferrocenyldiimine/NiBr 2 (1), 1,2-ferroceny

Ethylene/acrylate ester copolymerization was

ldiimine/NiBr2 (4), and 2-azaferrocenylimine/NiBr2 (7)performed in a 0.15 L stainless steel autoclave. NMR

were synthesized, and used as catalyst for the

spectra were recorded on a JEOL GSX-270WB (270ethylene polymerization and ethylene/acrylates

MHz) spectrometer. Chemical shifts for 1 H NMR

copolymerization. Although 1 had no polymerization

spectra were referenced to internal solvent references

activity for ethylene, 4 was found to work as catalyst for

and reported as parts per million relative toboth ethylene polymerization and ethylene/acrylates

tetramethylsilane. 1 H-NMR spectra of ethylene/2-

copolymerization. The polymerization method was

phenoxyethyl acrylate copolymers were measured inextended to use the complexes 7a-c. The catalytic[D 2 ]1,1,2,2-tetrachloroethane at 120℃. 13 C NMR

activity towand ethylene polymerization was 7 > 4 inspectra of polymers (about 15％ (w/v) solutions ofaccordance with the size of chelation sphere. We havesample) were measured in CDCl3 at 25℃ using a 10-

also found that the catalyst system consisting of 7,

mm sample tube. Chemical shifts were referenced toethylaluminum sesquichloride and borate drasticallythe major backbone methylene carbon resonance,

improved the activity for ethylene/acrylate copolymeri-

which was taken as 30.00 ppm downfield fromzation. Compared to the method of ethylene/acrylate

tetramethylsilane. High-temperature gel permeation

copolymerization by DuPont, our copolymerization

chromatography (GPC) was performed in 1,2,4-（ 20 ）

東ソー研究・技術報告 第48巻（2004）21

trichlorobenzene at 140℃ using a Tosoh HLC-8121GPC

Am. Chem. Soc ., 117, 6414 (1995); (b)/HT apparatus with TSKgel GMHhr-H(20)HT (× 3)

WO96/23010, to DuPont Co.; Chem. Abstr., 125,

columns. A calibration curve was established with
polystylene standards. Differential scanning calorimetry

222773t (1996); (c) D. P. Gates, S. A. Svejda, E.
〜ate, C. M. Killian, L. K. Johnson, P. S. White, M.
On

was recorded on a Seiko Instruments DSC200. A 8.7％

Brookhart, Macromolecules, 33, 2320 (2000).

Al (wt ％) solution of polymethylaluminoxane (PMAO)

3)(a) H. Yasuda, M. Furo, H. Yamamoto, A.

in toluene and a 20.3％ solution of ethylaluminum

Nakamura, S. Miyake, N. Kibino, Macromolecules,

sesquichloride in toluene were purchased from Tosoh-

25, 5115 (1992); (b) S. Mecking, L. K. Johnson, L.

Finechem Co. 2-Phenoxyethyl acrylate was purchased

Wang, M. Brookhart, J. Am. Chem. Soc., 120, 888

from Tokyo Kasei Kogyo Co., was degassed by(1998); (c) T. R. Younkin, E. F. Connor, J. Y.

repeated freeze-pump-thaw cycles and dried overHenderson, S. K. Friedrich, R. H. Grubbs, D. A.

Zeolite.

Bansleben, Science, 287, 460 (2000); (d) J. Imuta,［2］Typical ethylene/acrylate ester copolymerization

N. Kashiwa, Y. Toda, J. Am. Chem. Soc., 124, 1176

procedure(2002); (e) H. W. Boone, P. S. Athey, M. J. Mullins,

A 0.15 L stainless steel autoclave with a magnetic

D. Philipp, R. Muller, W. A. Goddard, J. Am. Chem.

stirrer bar was heated at 100℃ under vacuum for 1 hSoc., 124, 8790 (2002); (f) G. J. P. Britovsek, V. C.

and then cooled and repeated pressuring with nitrogen

Gibson, S. K. Spitzmesser, K. P. Tellmann, A. J. P.

to 0.7 MPa and venting three times. A suspension ofWhite, D. J. Williams, J. Chem. Soc., Dalton Trans.,

precatalyst (5-6 μmol) in toluene (15 mL) was injected

1159 (2002); (g) E. Drent, R. van Dijk, R. vaninto autoclave via a cannula at room temperature. Then,

Ginkel, B. van Oort, R. I. Pugh, Chem. Cummun.,the autoclave was pressurized with ethylene to 1 MPa

744 (2002).

and vented. Ethylaluminum sesquichloride (20.3％,

4)

L. Wang, E. Hauptman, L. K. Johnson, E. F.

1.48 M (Al) toluene solution, 0.5 mL, 0.74 mmol) and

MacCord, Y. Wang, S. D. Ittel, WO0192342 ,N , N -dimethylanilinium tetrakis(pentafluorophenyl)

DuPont Co.

borate (29.0 mg, 0.0361 mmol) in toluene (15 mL) were

5)

A. Togni, T. Hayashi, Ferrocenes, VCH,

added. And then, after 2-phenoxyethyl acrylate (0.5 mL,

Weinheim, Germany (1995); A. Shafir, J. Arnold, J.

2.86 mmol) was added, the autoclave was immediately

Am. Chem. Soc., 123, 9212 (2001).

pressurized with ethylene to 4 MPa, shaken, and placed

6)

N. I. Pyshnograeva, V. N. Setkina, D. N. Kursanov,in an oil bath at 80℃. The mixture was stirred at 80℃

Izv. Akad. Nauk SSSR, Ser. Khim., 2778 (1984); M.

for 10 h. Then the autoclave was vented and the

M. C. Lo, G. C. Fu, J. Am. Chem. Soc., 120, 10270

reaction mixture was poured into ethanol (200 mL) with

(1998).

stirring to precipitate the polymer, which was filtered

7)

M. Watanabe, T. Okada, M. Sato, S. Hamura, M.
Tanabiki, US Patent Appl., 2002/0120160, Tosohand dried in a vacuum oven at 50℃. The obtained1

polymers were characterized by H NMR, GPC andCo.; Chem. Abstr., 137, 201710 (2002); M.

DSC.

Watanabe, Macromol.Rapid Commun . 26, 34(2005) ; M. Watanabe, J. Organomet. Chem., to besubmitted.

5. References
1)8)

Organomet. Chem., 412, 381 (1991).

For reviews on late-transition-metal catalyzed
olefin polymerization, see : (a) G. J. P. Britovsek,

9)10) C. M. Killian, L. K. Johnson, M. Brookhart,

and M. Brookhart, Chem. Rev., 100, 1169 (2000);(c) V. C. Gibson and S. K. Spitzmesser, Chem .
2)

O. Riant, O. Samuel, T. Flessner, S. Taudien, H. B.
Kagan, J. Org. Chem., 62, 6733 (1997).

V. C. Gibson, and D. F. Wass, Angew. Chem. Int.

Ed., 38, 428 (1999); (b) S. D. Ittel, L. K. Johnson,

G. G. A. Balavoine, G. Doisneau, T. F.-Khan, J.

Organometallics, 16, 2005 (1997).
11) S. J. McLain, E. F. McCord, L. K. Johnson, S. D.

Rev., 103, 283 (2003).

Ittel, L. T. J. Nelson, S. D. Arthur, M. J. Halfhill,(a) L. K. Johnson, C. M. Killian, M. Brookhart, J.

M. F. Teasley, Polym. Prepr., 38, 772 (1997).

（ 21 ）

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TOSOH Research ＆ Technology Review Vol.48（2004）

著

者

氏名 渡 辺 真 人
Makoto WATANABE著者

氏名 岡 田 隆 志Takashi OKADA入社 昭和60年 4 月 1 日

入社 昭和62年 4 月 1 日

所属 四日市研究所新規分野

所属 四日市研究所新規分野

IT材料・環境材料グループ

光学材料・エラストマーグループ

主任研究員

主任研究員

（ 22 ）