Ni(II) and Pd(II) Olefin Polymerization Catalysts
Organometallics, Vol. 20, No. 11, 2001 2329
vacuo, and the complex was precipitated by addition of ether.
Finally the product was filtered, washed with ether and
n-pentane, and dried in vacuo.
131.63; 132.26; 133.22; 135.11; 135.37; 142.36; 143.22; 160.05;
171.37; 176.07. Anal. Calcd for C45H43ClN2O4Pd: C, 66.10; H,
5.30; N, 3.42 Found: C, 65.86; H, 5.38; N, 3.38.
4a : yellow powder; yield 940 mg (82%). 1H NMR (C2D2Cl4):
δ 1.43 (s, -CH3, 6H); 7.07-7.31 (m, arom, 26H). 13C NMR
(C2D2Cl4): δ 16.52, 124.42, 126.93, 127.93, 128.97, 129.56,
131.20, 139.53, 145.82, 167.21. Anal. Calcd for C40H32Cl2N2-
Pd: C, 66.85; H, 4.46; N, 3.89 Found: C, 66.95; H, 4.43; N,
3.66.
Met h ylch lor or o(2,3-b u t a n ed ion e-b is-4-ter t-b u t ylt er -
p h en ylim in e))p a lla d iu m (II) (5c). In a 250 mL Schlenk flask
0.8 g (0.84 mmol) of compound 4c was dissolved in 80 mL of
methylene chloride. After the addition of a catalytic amount
of Et3NH4Cl, 0.3 mL (2.1 mmol) of Sn(CH3)4 was added via
syringe, and the reaction mixture was stirred at room tem-
erature for 40 h. The resulting orange solution was filteredand
reduced to a volume of about 20 mL. The product was
precipitated by addition of ether. Finally the solvent was
removed via filtration, and the complex was washed with ether
and dried in vacuo.
5c: orange powder; yield 0.542 g (70%). 1H NMR (C2D2-
Cl4): δ 0.41 (s, -CH3, 3H), 1.07 (s, -CH3, 3H), 1.11 (s, -CH3,
3H), 1.32 (d, -CH3, 36H), 7.23-7.54 (m, arom, 22H). 13C NMR
(C2D2Cl4): δ 7.86; 20,44, 21.53; 31.45; 31.48; 34.55; 34.61;
124.65; 125.12; 127.03; 127.88; 129.58; 130.10; 134.26; 134.64;
135.80; 136.55; 141.26; 141.43; 150.24; 150.80; 156.53; 171.13;
175.21. Anal. Calcd for C57H67ClN2Pd: C, 74.18; H, 7.27; N,
3.04. Found: C, 73.95; H, 7.20; N, 3.01.
Dich lor o(2,3-b u t a n e d ion e b is-4-m e t h oxyt e r p h e n yl-
im in e))p a lla d iu m (II) (4b). In a 500 mL Schlenk flask con-
taining 1.15 g (3.0 mmol) of (PhCN)2PdCl2, 250 mL of meth-
ylene chloride and 2.0 g (3.05 mmol) of ligand 3b were added.
After a few minutes the color of the reaction mixture changed
to dark red. The mixture was stirred for 72 h at room
temperature. Then the methylene chloride was removed in
vacuo until only about 15 mL of the solvent remained. Then
the complex was precipitated by addition of 50 mL of n-
pentane. The solvents were removed via filtration, and the
product was washed with n-pentane and dried in vacuo.
1
4b: orange powder; yield 2.44 g (97%). H NMR (C2D2Cl4):
δ 1.55 (s, -CH3, 6H); 3.91 (s, -O-CH3, 12H); 6.82 (d, arom,
8H); 7.19 (d, arom, 4H); 7.44 (m, arom, 10H). 13C NMR: (C2D2-
Cl4): δ 21.21; 55.46; 114.33; 128.55; 130.66; 131.02; 131.18;
135.00; 140.68; 159.03; 178.12. Anal. Calcd for C44H40Cl2N2O4-
Pd: C, 63.05; H, 4.81; N, 3.34 Found: C, 62.62; H, 4.87; N,
3.35.
Syn th esis of th e Nick el Ca ta lysts. The nickel complexes
were performed in situ by reaction of the ligand with (DME)-
NiBr2 in toluene for 12 h. The resulting solutions were directly
activated by addition of MAO and used for polymerizations.
Dich lor o(2,3-b u t a n ed ion eb is-4-ter t-b u t ylt er p h en yl-
im in e))p a lla d iu m (II) (4c). Following the procedure described
for compound 4b, 652 mg (1.7 mmol) of (C6H5CN)2PdCl2 and
1.43 g (1.86 mmol) of ligand 3c were converted in 75 mL of
methylene chloride to the palladium dichloro complex.
4c: dark orange powder; yield 1.36 g (85%). 1H NMR (C2D2-
Cl4): δ 1.22 (s, -CH3, 6H), 1.38 (s, -CH3, 36H), 7.15 (d, arom,
8H), 7.23 (t, arom, 2H), 7.35 (t, arom, 12H). 13C NMR (C2D2-
Cl4): δ 17.85, 31.54, 34.51, 124.11, 124.79, 128.9, 129.46,
P olym er iza tion Rea ction s w ith Eth ylen e. P a lla d iu m
Mon och lor o Com p ou n d s. The calculated amount of the
catalyst was dissolved in methylene chloride (50 mL/100 mL
steel reactor, 30 mL/50 mL steel reactor) under argon. Two
equivalents of NaB(Ar′)4 was added, and the autoclave was
pressurized with ethene. The pressure was kept constant dur-
ing the reaction time. The polymerizations were stopped by
pouring the reaction mixture into methanol. The polymers
were filtered, washed with methanol, and dried in vacuo over-
night. Polyethene was obtained in yields from 0.3 to 1.05 g.
131.59, 137.26, 145.71, 149.54, 167.89. Anal. Calcd for C56H64
-
Cl2N2Pd: C, 71.30; H, 6.79; N, 2.97. Found: C, 70.97; H, 6.86;
N, 2.99.
P a lla d iu m Dich lor o Com p ou n d s. Polymerizations were
performed using the above-described procedure in a 50 mL
steel autoclave, in which toluene, cocatalyst MAO, and the
catalyst were fed under argon. The polymerizations were
quenched by pouring the reaction mixture in acidified metha-
nol. Polyethene was obtained in yields from 0.75 to 3.24 g.
Met h ylch lor o(2,3-b u t a n ed ion eb is(t er p h en ylim in e))-
p a lla d iu m (II) (5a ). Ether (75 mL) was added to a Schlenk
flask containing 530 mg (2.0 mmol) of (COD)PdMeCl and a
slight excess of ligand 3a (1.13 g, 2.1 mmol). An orange
precipitate began to form immediately upon mixing. The
reaction mixture was stirred overnight, and the ether and free
COD were removed via filtration. The product was washed
with ether and dried in vacuo.
Nick el Dibr om o Com p ou n d s. A 2000 mL steel autoclave
was charged with 800 mL of toluene under argon. In case of
the hydrogen experiments, a pressure buret was repeatedly
pressurized with hydrogen (V ) 10 mL, p ) 20 bar) and
exhausted into the reactor until the desired hydrogen concen-
tration was obtained. Then the reactor was pressurized with
ethene. After the solution was saturated with monomer, the
activated catalyst solution was injected into the autoclave via
a pressure buret. The pressure was kept constant during the
entire polymerization period. The polymerization reactions
were stopped and treated as described above yielding 20-101
g of polyethene.
1
5a : orange powder; yield 1.03 g (74%). H NMR (C2D2Cl4):
δ 0.65 (s, -CH3, 3H); 1.53 (s, -CH3, 3H), 1.57 (s, -CH3, 3H),
7.09-7.49 (m, arom, 24H), 7.62 (d, arom, 3H). 13C NMR (C2D2-
Cl4): δ 1.77; 20.23; 22.18; 126.45; 127.39; 127.69; 127.72;
128.45; 128.69; 128.81; 129.43; 130.96; 131.34; 134.26; 134.49;
138.42; 139.18; 140.91; 141.68; 169.95; 174.60. Anal. Calcd for
C41H35ClN2Pd: C, 70.57; H, 5.06; N, 4.01. Found: C, 70.57;
H, 5.04; N, 4.05.
Me t h y lc h lo r o (2,3-b u t a n e d io n e b is -4-m e t h o x y t e r -
p h en ylim in e))p a lla d iu m (II) (5b). In a 250 mL Schlenk flask
0.6 g (0.71 mmol) of compound 4b was suspended in 120 mL
of methylene chloride. Sn(CH3)4 (0.25 mL, 1.77 mmol) was
added via syringe, and the reaction mixture was stirred at
room temperature for 40 h. The resulting red solution was
filtered and reduced to a volume of about 20 mL. The product
was precipitated by addition of 150 mL of ether using an ice
bath for cooling. The solvent was removed via filtration, and
the complex was washed with ether and dried in vacuo.
5b: orange powder; yield 0.4 g (69%). 1H NMR (C2D2Cl4):
δ 0.64 (s, Pd-CH3, 3H); 1.40 (s, -CH3, 3H); 1.42 (s, -CH3,
3H); 3.84 (s, -O-CH3, 6H); 3.85 (s, -O-CH3, 6H); 6.68 (d,
arom, 4H); 6.81 (d, arom, 4H); 7.17 (d, arom, 6H); 7.24 (d, arom,
2H); 7.31 (m, arom, 2H); 7.63 (d, arom, 4H). 13C NMR (C2D2-
Cl4): δ 3.27; 21.36; 23.05; 56.75; 115.13; 115.48; 127.93; 128.84;
P olym er An a lysis. The soluble polymers were analyzed
1
by H and 13C NMR on a Bruker AC 200 or AMX 500 at 80 °C
in C2D2Cl4. Molecular weights were determined by a Waters
150 C ALC/GPC system in 1,2,4-triclorobenzene at 135 °C.
DSC measurements were done using a Perkin-Elmer series 7
DSC instrument.
Ack n ow led gm en t. We are grateful to Prof. Dr.
Markku Ahlgren, Department of Chemistry, University
of J oensuu, Finland, for collecting the X-ray data of 4c.
We also wish to thank Prof. Ulf Thewalt, Section for
X-Ray and Electron Diffraction, University of Ulm, for
the structure solution of 4b. Finally we are grateful to