Substituent effects in (κ2-N,O)-salicylaldiminato nickel(II)-methyl pyridine polymerization catalysts: Terphenyls controlling polyethylene microstructures

Article abstract of DOI:10.1021/om0611498

A series of (κ²-N,O)-salicylaldiminato Ni(II)-methyl pyridine complexes 7-pyr and 8-pyr derived from 3,5-diiodosalicyaldehyde (3a) and 3-(9-anthryl)salicylaldehyde (3b), and terphenylamines 2,6-(3,5-R-4- R′-C₆H₂)₂C₆H ₃-NH₂ (4a, R = CF₃, R′ = H; 4b, R = ^tBu, R′ = H; 4c, R = ^tBu, R′ = OH; 4d, R = Me, R′ = H; 4e, R = Me, R′ = MeO; 4f, R = MeO, R′ = H; 4g, R = MeO, R′ = MeO), was prepared by reaction of the respective salicylaldimine (5a-f, 6a-g) with [(tmeda)Ni(CH₃)₂] (tmeda = N,N,N′ N′-tetramethylethylenediamine) or [(pyridine)₂Ni(CH ₃)₂]. Complexes 7-pyr and 8-pyr are highly active single component catalysts for the polymerization of ethylene, producing a wide range of different polyethylene microstructures. While comparable complexes derived from 3a, 3b, 5-nitrosalicylaldehyde, 3-tertbutylsalicylaldehyde, 3,5-[3,5-(CF₃)₂C₆H₃] ₂-salicylaldehyde, and 2,6-[3,5-(CF₃)₂C ₆H₃]₂C₆H₃-NH₂ afford polyethylenes with similar degrees of branching, variation of the terphenyl moieties in complexes 7-pyr and 8-pyr allows access to a wide range of polyethylene microstructures under identical reaction conditions. The X-ray diffraction analyses of complexes 7b-pyr and 8f-pyr are reported.

Full text of DOI:10.1021/om0611498

2348
Organometallics 2007, 26, 2348-2362
Substituent Effects in (K2-N,O)-Salicylaldiminato Nickel(II)-Methyl
Pyridine Polymerization Catalysts: Terphenyls Controlling
Polyethylene Microstructures
Inigo Go¨ttker-Schnetmann,† Peter Wehrmann,† Caroline Ro¨hr,‡ and Stefan Mecking*,†
UniVersita¨t Konstanz, Fachbereich Chemie, UniVersita¨tsstrasse 10, D-78457 Konstanz, Germany, and
Institut fu¨r Anorganische und Analytische Chemie, UniVersita¨t Freiburg, Albertstrasse 21,
D-79104 Freiburg i. Br., Germany
ReceiVed December 19, 2006
A series of (κ2-N,O)-salicylaldiminato Ni(II)-methyl pyridine complexes 7-pyr and 8-pyr derived
from 3,5-diiodosalicyaldehyde (3a) and 3-(9-anthryl)salicylaldehyde (3b), and terphenylamines 2,6-(3,5-
t
t
R-4-R′-C6H2)2C6H3-NH2 (4a, R ) CF3, R′ ) H; 4b, R ) Bu, R′ ) H; 4c, R ) Bu, R′ ) OH; 4d, R
) Me, R′ ) H; 4e, R ) Me, R′ ) MeO; 4f, R ) MeO, R′ ) H; 4g, R ) MeO, R′ ) MeO), was prepared
by reaction of the respective salicylaldimine (5a-f, 6a-g) with [(tmeda)Ni(CH3)2] (tmeda ) N,N,N′,N′-
tetramethylethylenediamine) or [(pyridine)2Ni(CH3)2]. Complexes 7-pyr and 8-pyr are highly active single
component catalysts for the polymerization of ethylene, producing a wide range of different polyethylene
microstructures. While comparable complexes derived from 3a, 3b, 5-nitrosalicylaldehyde, 3-tert-
butylsalicylaldehyde, 3,5-[3,5-(CF3)2C6H3]2-salicylaldehyde, and 2,6-[3,5-(CF3)2C6H3]2C6H3-NH2 afford
polyethylenes with similar degrees of branching, variation of the terphenyl moieties in complexes 7-pyr
and 8-pyr allows access to a wide range of polyethylene microstructures under identical reaction conditions.
The X-ray diffraction analyses of complexes 7b-pyr and 8f-pyr are reported.
catalysts promoting ethylene polymerization in the absence of
any activator.7 Even a small number of complexes where
displacement of phosphines by ethylene is prerequisite for
ethylene insertion behave as single component catalysts produc-
ing high molecular weight polyethylene,7d,e,8,9 instead of the most
commonly observed oligomers.10 Particularly, neutral κ2-(N,O)-
salicylaldiminato nickel methyl or phenyl complexes of type 1
were reported to be highly active and stable precatalysts tolerant
to polar media, and to produce high crystallinity high molecular
weight polyethylene, even when L ) PPh3 and no phosphine
scavenger was present (Chart 1).7d The steric bulk of the anthryl
Introduction
The discovery of highly active nickel and palladium diimine
catalysts for the polymerization of ethylene and R-olefins1 has
triggered an outburst of research activity in the field of late
transition metal-catalyzed olefin polymerization. Issues of
academic and industrial interest, such as, for example, the
copolymerization of ethylene and 1-olefins with polar acrylate
monomers incompatible with early transition metal polymeri-
zation catalysts,2 or the incorporation of substantial branching
in ethylene homopolymers by catalytic polymerization,1,3 have
been met early on, providing access to new polymer micro-
structures and material properties. Further, single component
precatalysts have been proven synthetically accessible,1 thereby
enabling detailed mechanistic studies and a deeper understanding
of the processes involved in late transition metal-catalyzed
insertion polymerization not only by these catalysts.4
(6) For earlier work reporting nickel-based polymerization catalysts,
see: (a) Keim, W.; Kowaldt, F. H.; Goddard, R.; Kru¨ger, C. Angew. Chem.,
Int. Ed. Engl. 1978, 17, 466-467. (b) Reference 3a,b. (c) Ostoja Starzewski,
K. A.; Witte, J. Angew. Chem., Int. Ed. Engl. 1985, 24, 599-601. (d)
Klabunde, U.; Ittel, S. D. J. Mol. Catal. 1987, 41, 123-134.
(7) Neutral nickel P,O-chelates (SHOP-type): (a) Reference 6a-d. (b)
Kuhn, P.; Se´meril, D.; Jeunesse, C.; Matt, D.; Neuburger, M.; Mota, A.
Chem.-Eur. J. 2006, 12, 5210-5219. (c) Nickel/palladium diimine com-
plexes: ref 1. (d) Nickel salicylaldiminato complexes: Younkin, T. R.;
Connor, E. F.; Henderson, J. I.; Friedrich, S. K.; Grubbs, R. H.; Bansleben,
D. A. Science 2000, 287, 460-462. (e) Nickel anilinotropone complexes:
Hicks, F. A.; Brookhart, M. Organometallics 2001, 20, 3217-3219. (f)
Cationic nickel P,O-chelates: Liu, W.; Malinoski, J. M.; Brookhart, M.
Organometallics 2002, 21, 2836-2838. (g) Cyclopentadienyl cobalt
complexes: Daugulis, O.; Brookhart, M.; White, P. S. Organometallics
2003, 22, 4699-4704. (h) Neutral iminopropanamide complexes: Diamanti,
S. J.; Ghosh, P.; Shimizu, F.; Bazan, G. C. Macromolecules 2003, 36, 9731-
9735.
Following these findings, new families of highly active late
transition metal olefin polymerization precatalysts have been
developed.5,6 These include a minor number of single component
* Corresponding author. E-mail: stefan.mecking@uni-konstanz.de.
† Universita¨t Konstanz.
‡ Universita¨t Freiburg.
(1) Johnson, L. K.; Killian, C. M.; Brookhart, M. J. Am. Chem. Soc.
1995, 117, 6414-6415.
(2) Mecking, S.; Johnson, L. K.; Wang, L.; Brookhart, M. J. Am. Chem.
Soc. 1998, 120, 888-899.
(3) For an earlier example of a nickel(II) complex producing branched,
low molecular weight ethylene homopolymer, see: (a) Keim, W.; Appel,
R.; Storeck, A.; Kru¨ger, C.; Goddard, R. Angew. Chem., Int. Ed. Engl. 1981,
20, 116-117. (b) Keim, W. Ann. N.Y. Acad. Sci. 1983, 415, 191-200.
(4) (a) Svejda, S. A.; Johnson, L. K.; Brookhart, M. J. Am. Chem. Soc.
1999, 121, 10634-10635. (b) Tempel, D. J.; Johnson, L. K.; Huff, R. L.;
White, P. S.; Brookhart, M. J. Am. Chem. Soc. 2000, 122, 6686-6700.
(5) For reviews, see: (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, 283-316. (c) Mecking, S. Coord. Chem. ReV. 2000, 203,
325-351. (d) Mecking, S. Angew. Chem., Int. Ed. 2001, 40, 534-540.
(8) (a) Jenkins, J. C.; Brookhart, M. Organometallics 2003, 22, 250-
256. (b) Hicks, F. A.; Jenkins, J. C.; Brookhart, M. Organometallics 2003,
24, 3533-3545. (c) Jenkins, J. C.; Brookhart, M. J. Am. Chem. Soc. 2004,
126, 5827-5842.
(9) Go¨ttker-Schnetmann, I.; Korthals, B.; Mecking, S. J. Am. Chem. Soc.
2006, 128, 7708-7709.
(10) Representative oligomerization catalysts: (a) Reference 6a. (b)
Desjardins, S. Y.; Cavell, K. J.; Jin, H.; Skelton, B. W.; White, A. H. J.
Organomet. Chem. 1996, 515, 233-243. (c) Pietsch, J.; Braunstein, P.;
Chauvin, Y. New J. Chem. 1998, 467-472. (d) Chen, Y.; Wu, G.; Bazan,
G. C. Angew. Chem., Int. Ed. 2005, 44, 1108-1112.
10.1021/om0611498 CCC: $37.00 © 2007 American Chemical Society
Publication on Web 03/28/2007

Nickel(II)-Methyl Pyridine Polymerization Catalysts
Organometallics, Vol. 26, No. 9, 2007 2349
Chart 1. K2-(N,O)-Salicylaldiminato Nickel Methyl Complexes of Type 1, 2, 7, and 8
Scheme 1. Synthesis of 3-(9-Anthryl)salicylaldehyde (3b)
substituent in 1b-PPh3 is believed to promote phosphine
dissociation from 1b, and to protect the catalytically active nickel
center toward deactivation routes, which ultimately afford bis-
chelate complexes [(κ2-N,O)2Ni], thus facilitating long-lasting
high activity ethylene polymerization.7d,11,12,16d
Driven by our interest to conduct ethylene polymerization in
highly polar aqueous media,13 we have shown that a similar
and easily accessible κ2-(N,O)-salicylaldiminato nickel-methyl
pyridine complex 2-pyr derived from commercially available
3,5-diiodosalicylaldehyde produces high molecular weight
polyethylene dispersions in aqueous miniemulsion, although its
activity is an order of magnitude smaller in aqueous systems
as compared to homogeneous toluene solution.14 Interestingly,
replacement of the 2,6-diisopropylphenyl moiety by different
terphenyls led to much more active precatalysts 7a,d,f-pyr that,
in addition, produced materials ranging from high molecular
weight semicrystalline polyethylene with a low degree of
branching to low molecular weight amorphous material with a
high degree of branching depending on the 3′,5′-substitution of
the terphenyl under otherwise identical reaction conditions.15
These findings and the reported high activity of complexes 1-L
(vide supra) have prompted us to combine the (expected) high
activity supported by the anthryl substitution and the possibility
to influence the microstructure of the produced polymers by
introducing different terphenyl substituents in complexes of type
8-pyr (Chart 1). Here, we report the synthesis and the catalytic
activity of new κ2-(N,O)-salicylaldiminato nickel methyl com-
Scheme 2. Synthesis of Salicylaldimines 5a-f, 6a-g
plexes of type 7-pyr and 8-pyr as well as the microstructures
of the polyethylenes obtained.
Results and Discussion
Improved Synthesis of 3-(9-Anthryl)salicylaldehyde (3b).
In contrast to commercially available 3,5-diiodosalicylaldehyde
(3a), 3-(9-anthryl)salicylaldehyde (3b) is only accessible via
multistep syntheses in moderate to good yield.16 In analogy to
a procedure developed by Grubbs et al.,12,16b we have improved
and simplified the synthesis of 3b (67% overall yield) starting
from 2-bromoanisole and anthrone by (a) conducting the final
formylation/oxidation sequence of 2-(9-anthryl)phenol in the
presence of freshly prepared MgBr2‚(Et2O)n under strict TLC
control (Scheme 1),17 and (b) cocrystallization of the product
as 3b‚1/2CH2Cl2 from the crude reaction mixture in CH3OH/
CH2Cl2, thus avoiding chromatographic workup (see experi-
mental section for details).
Synthesis of Salicylaldimines 5a-f, 6a-g. Condensation of
aldehydes 3a,b with m-terphenylamines 4a-g that are readily
accessible from 2,6-dibromoaniline and the respective 3,5-
substituted aryl boronic acids (for details, see experimental part)
yields the desired salicylaldimines in high yields (78-94%) in
analogy to known procedures (Scheme 2 and Table 1). In most
cases, the low solubility of the salicylaldimines in CH3OH
enables their straightforward isolation from the crude reaction
(11) Chan, M. S. W.; Deng, L. Q.; Ziegler, T. Organometallics 2000,
19, 2741-2750.
(12) Connor, E. F.; Younkin, T. R.; Henderson, J. I.; Waltman, A. W.;
Grubbs, R. H. Chem. Commun. 2003, 2272-2273.
(13) (a) Mecking, S.; Held, A.; Bauers, F. M. Angew. Chem., Int. Ed.
2002, 41, 544-561. (b) Mecking, S.; Claverie, J. In Late Transition Metal
Polymerization Catalysis; Rieger, B., Baugh, L. S., Kacker, S., Striegler,
S., Eds.; Wiley-VCH: Weinheim, 2003; pp 231-278. (c) Claverie, J. P.;
Soula, R. Prog. Polym. Sci. 2003, 28, 619-662. (d) Mecking, S. Colloid
Polym. Sci. 2007, 285, 605-619.
(14) (a) Bauers, F. M.; Mecking, S. Angew. Chem., Int. Ed. 2001, 40,
3020-3022. (b) Bauers, F. M.; Mecking, S. Macromolecules 2001, 34,
1165-1167.
(15) Zuideveld, M.; Wehrmann, P.; Ro¨hr, C.; Mecking, S. Angew. Chem.,
Int. Ed. 2004, 43, 869-873.
(16) Viable synthetic routes are reported by, for example: (a) Bansleben,
D. A.; Friedrich, S. K.; Younkin, T. R.; Grubbs, R. H.; Wang, C.; Li, R. T.
WO Patent Application 9842664 to W. R. Grace & Co. (b) Wang, C.;
Friedrich, S.; Younkin, T. R.; Li, R. T.; Grubbs, R. H.; Bansleben, D. A.;
Day, M. W. Organometallics 1998, 17, 3149-3151. (c) Bansleben, D. A.;
Friedrich, S.; Younkin, T. R.; Grubbs, R. H.; Wang, C.; Li, R. T. U.S.
Patent Application 6410664 to Cryovac Inc. (d) Bansleben, D. A.; Connor,
E. F.; Grubbs, R. H.; Henderson, J. I.; Younkin, T. R.; Nadjydi, A. R., Jr.
WO Patent Application 2000056787 to Cryovac Inc. (e) Gibson, V. C.;
Goh, C.; Yong, P. K. WO Patent Application 2002090365 to BP Chemicals
Limited. (f) Reference 12. (g) Jones, D. J.; Gibson, V. C.; Green, S. M.;
Maddox, P. J.; White, A. J. P.; Williams, D. J. J. Am. Chem. Soc. 2005,
127, 11037-11046.
(17) Commercially available Lewis acids, for example, SnCl4, MgCl2,
and MgBr2, did not perform as good as freshly prepared MgBr2 diethyl
ether complex.

2350 Organometallics, Vol. 26, No. 9, 2007
Table 1. Synthesis of Salicylaldimines 5a-f, 6a-g
Go¨ttker-Schnetmann et al.
salicylaldehyde
terphenylamine
product salicylaldimines
3
4
yield
entry
5
6
R1
R2
R3
R4
5,6 [%]e
1a
2
ac
bc
cd
dc
ec
fc
a
a
a
a
a
a
b
b
b
b
b
b
b
I
I
I
I
I
I
I
I
I
I
I
I
H
H
H
H
H
H
H
a
b
c
d
e
f
a
b
c
d
e
f
CF3
tBu
H
H
OH
H
MeO
H
H
H
OH
H
MeO
H
87f
83
3b
4a
5
tBu
83b
90f
94
Me
Me
6a
7b
8
MeO
CF3
tBu
91f
92b
93
ac
bc
cc
dc
ec
fd
Ant
Ant
Ant
Ant
Ant
Ant
Ant
9b
10
11
12
13
tBu
92b
86
Me
Me
MeO
MeO
89
78
94
gc
g
MeO
a See ref 15. b See ref 9. c Obtained from methanol/cat. p-TsOH. d Obtained from refluxing toluene/cat. p-TsOH. e Isolated yield. f The general procedure
described here (cf. experimental section) gave higher yields than the procedure reported in ref 15.
Scheme 3. Synthesis of K2-(N,O)-Salicylaldiminato
Nickel(II) Methyl Pyridine Complexes 7-pyr and 8-pyr
methyl-containing species and methane within less than 15 min
at 25 °C. At this point, excess pyridine present in the reaction
mixture results in dynamical broadening of all signals observed.
However, after removal of the (frozen) solvent and excess
pyridine, and redissolution in benzene-d6, exclusively one
1
(sharp) set of signals is observed by H NMR spectroscopy
originating from compound 7a-pyr. Reaction of salicylaldimines
5a-f, 6a-g with both [(tmeda)Ni(CH3)2] and [(pyridine)2Ni-
(CH3)2] gave similarly high yields. Table 2 gives the method
performing better overall including preparative workup.
Additional phenolic (i.e., acidic) protons present in the
terphenyl moieties of salicylaldimines 5c and 6c or complexes
7c-pyr and 8c-pyr (R3 ) tBu, R4 ) OH) do not interfere with
either nickel-methyl source, that is, [(tmeda)Ni(CH3)2],
[(pyridine)2Ni(CH3)2], or the formed products 7c-pyr, 8c-pyr
to a noticeable extent on the basis of (a) the integration of an
suspensions by filtration. Efficient condensation of 3b with 4f
could not be achieved in methanol due to incomplete conversion.
However, azeotropic water removal in toluene gave the desired
salicylaldimine 6f in good yield.
1
observable H NMR resonances of these phenolic protons for
7c-pyr and 8c-pyr, (b) similarly high stabilities of benzene-d6
solutions of all complexes 7 and 8 over weeks without detectable
decomposition or formation of methane in the absence of
oxygen, and (c) similarly high yields as compared to the
synthesis of all other complexes 7-pyr and 8-pyr. The high
selectivity of either nickel-methyl source for the salicyl OH-
group as well as the stability of complexes 7c, 8c is likely related
to a higher acidity when compared to the terphenyl OH-groups.
In addition, the terphenyl OH-groups are more sterically
Synthesis of K2-(N,O)-Salicylaldiminato Nickel(II) Methyl
Pyridine Complexes (7a-f-pyr, 8a-g-pyr). Preparation of
complexes 7a-f-pyr and 8a-g-pyr was accomplished by
reaction of the respective salicylaldimine 5a-f, 6a-g either
with 1 equiv of [(tmeda)Ni(CH3)2]18 and 15 equiv of pyridine
(method A) or with 1.05 equiv of the recently reported
[(pyridine)2Ni(CH3)2]19 (method B) in diethyl ether suspension
or benzene solution at 25 °C under strict exclusion of oxygen
(Scheme 3). In our view, the use of [(pyridine)2Ni(CH3)2]
simplifies the synthesis of complexes 7-pyr and 8-pyr as it is
more readily accessible than [(tmeda)Ni(CH3)2] (although not
more stable).20
t
protected by the adjacent Bu-groups when compared to the
salicyl OH-group.
All complexes 7-pyr and 8-pyr are diamagnetic in solution
as evidenced by sharp resonances except for the (somewhat
dynamically broadened) signals of the pyridine ligand in the
1H and 13C NMR spectra. Therefore, a square planar coordina-
tion geometry of the nickel center is proposed for all new
complexes 7-pyr and 8-pyr. Most characteristic, the nickel-
bound methyl groups resonate between -0.5 and -1.1 ppm in
Consumption of the starting salicylaldimines 5a-f, 6a-g and
either nickel-dimethyl source is particularly fast in benzene
solution as evidenced by the observable ceasing of methane
evolution within 5-10 min at 25 °C. 1H NMR monitoring of a
1:1 reaction mixture of 5a and [(pyridine)2Ni(CH3)2] in benzene-
d6 (J. Young tube) reveals a clean conversion to one nickel-
1
the H NMR and between -7.6 and -9.1 in the 13C NMR
spectra, respectively, for all complexes 7-pyr and 8-pyr. The
2′- and 6′-positions as well as substituents in the 3′- and 5′-
positions of the m-terphenyl moieties give rise to one set of
13C and 1H NMR resonances for all complexes 7-pyr and 8-pyr,
respectively, at 25 °C, indicating free rotation of the 3′,5′-
disubstituted arene rings (for the numbering, refer to Chart 2).21
(18) Kaschube, W.; Po¨rschke, K. R.; Wilke, G. J. Organomet. Chem.
1988, 355, 525-532.
(19) Ca´mpora, J.; Conejo, M. d. M.; Mereiter, K.; Palma, P.; Pe´rez, C.;
Reyes, M. L.; Ruiz, C. J. Organomet. Chem. 2003, 683, 220-239.
(20) We note that the versatility of [(pyridine)2Ni(CH3)2] is somewhat
restricted when compared to [(tmeda)Ni(CH3)2]: While stronger coordinat-
ing and less volatile donor ligands such as phosphines displace pyridine in,
for example, complex 7a-pyr, preparation of similar acetonitrile complexes
requires the use of [(tmeda)Ni(CH3)2], because displacement of pyridine
by acetonitrile is not complete even when a huge excess of acetonitrile is
used: Go¨ttker-Schnetmann, I.; Berkefeld, A.; Mecking, S., unpublished
results.
(21) For a detailed investigation on the rotation in related ortho-
monoalkyl-biaryls, see: (a) Lunazzi, L.; Mazzanti, A.; Minzoni, M.;
Anderson, J. E. Org. Lett. 2005, 7, 1291-1294. (b) Mazzanti, A.; Lunazzi,
L.; Minzoni, M.; Andreson, J. E. J. Org. Chem. 2006, 71, 5474-5481.

Nickel(II)-Methyl Pyridine Polymerization Catalysts
Organometallics, Vol. 26, No. 9, 2007 2351
Table 2. Synthesis of K2-(N,O)-Salicylaldiminato Nickel(II) Methyl Pyridine Complexes 7-pyr and 8-pyr
7a-pyr
7b-pyr
7c-pyr
7d-pyr
7e-pyr
7f-pyr
8a-pyr
8b-pyr
8c-pyr
8d-pyr
8e-pyr
8f-pyr
8g-pyr
R1
I
I
I
I
I
I
I
I
I
I
I
I
Ant
H
CF3
H
92
B
Ant
H
Ant
H
Ant
H
Me
H
89
A
Ant
H
Me
MeO
96
Ant
H
MeO
H
92
B
Ant
H
MeO
MeO
92
R2
R3
CF3
H
tBu
H
93
A
tBu
OH
91
B
Me
H
Me
MeO
91
B
MeO
H
tBu
H
tBu
OH
91
R4
yield [%]a
method
>90b
A
>90b
A
>90b
A
91
B
A
B
B
a Isolated yield. b Yield taken from ref 15. (A) Starting from [(tmeda)Ni(CH3)2]. (B) Starting from [(pyridine)2Ni(CH3)2].
Chart 2. Numbering of the m-Terphenyl Moieties in
Complexes 7-pyr and 8-pyr
4
Additional features comprise the observation of JHH cou-
plings (1.8-2.2 Hz) for the 4- and 6-protons of the 3,5-
diiodosalicylaldimine moieties of complexes 7-pyr. Further,
characteristic high field shifts of the averaged ortho- (δ ) 7.40-
7.32), meta- (5.82-5.54 ppm), and the para-protons (6.27-
6.14 ppm) of the nickel-bound pyridine ligand in complexes
8-pyr are observed (likely arising from anisotropic shielding
by the anthryl substituent) when compared to complexes 7-pyr
(o-H, 8.34-8.18; m-H, 6.40-6.31; p-H, 6.70-6.62 ppm) and
free pyridine (for details, see experimental section).
While complexes 7a-f-pyr and 8a-e-pyr are isomerically
pure by 1H NMR spectroscopy and exhibit a trans-arrangement
of the phenolic oxygen and the methyl group bound to the nickel
center as evidenced by NOESY experiments of 7b-,7c-pyr and
8a-c-pyr, minor amounts of a second isomer with a supposed
cis-arrangement of nickel bound oxygen and the methyl group
are detectable for the anthryl-substituted complexes 8f-pyr
(trans:cis: ca. 12:1) and 8g-pyr (trans:cis: ca. 20:1).22 Such a
mixture of trans- and cis-isomers (in a 3:1 ratio) was also
observed for the anthryl-substituted complex 1a-CH3CN (Chart
1) in solution, with the trans- and cis-isomers exchanging on
the NMR time scale, while complex 1b-PPh3 (Chart 1) exhibits
exclusively trans-geometry in solution.12,16b For comparison of
catalytic activity, we have prepared the novel pyridine complex
1a-pyr and note here that in benzene-d6 solution 1a-pyr exists
exclusively as the trans-isomer. We therefore conclude that
while fine-tuning (cf., the trans:cis ratios in 8f-pyr and 8g-
pyr) is already influenced by pure electronics of the ligand
backbone (i.e., the salicylaldimine 6f or 6g in complexes 8f-
pyr and 8g-pyr), a more coarse influence is exerted by the
stereoelectronic nature of the respective donor-ligand (i.e.,
pyridine vs acetonitrile in 1a-pyr vs 1a-CH3CN).
Figure 1. X-ray diffraction analysis of complex 7b-pyr with 50%
probability ellipsoids. The solid-state structure is disordered with
the tert-butyl group C351-C357 occupying two split positions.
Hydrogen atoms and cocrystallized solvent molecules are omitted
for clarity. Selected bond distances and angles are given in
Table 3.
Bond distances and angles for the nickel center are in the
expected range and show only minor deviations when compared
to 7a-pyr15 and 1a-CH3CN12 (Table 3).
The positioning of the terphenyl moiety closely resembles
that in the already known structure of 7a-pyr,15 given, for
example, by similar dihedral angles C10-N1-C21-C26 (7a-
pyr, 72°; 7b-pyr, 62°; 8f-pyr, 65°), C21-C26-C41-C42 (7a-
pyr, 40°; 7b-pyr, 62°; 8f-pyr, 46°), and C21-C22-C31-C36
(7a-pyr, 63°; 7b-pyr, 48°; 8f-pyr, 46°) (for the numbering
scheme, refer to Figure 1). A marked difference found in the
coordination sphere of the nickel center of these complexes is
the positioning of the pyridine ring, given, for example, by the
dihedral angle O1-Ni-N2-C51 -51° (7b-pyr), -47° (8f-
pyr), when compared to -107° (7a-pyr).
In view of the influence of the 3′,5′-substituents of the
terphenyl moieties on the polymer microstructure obtained (vide
infra), we note here that the closest distance between the nickel
center and a tert-butyl methyl-carbon in 7b-pyr (i.e., Ni1-C351,
Figure 1) amounts to 4.190 as compared to 4.355 Å for the
shortest Ni-CF3-distance in the solid-state structure of complex
7a-pyr.15 With respect to complex 8f-pyr, the closest distance
of the nickel center to a 3′,5′-methoxy-carbon atom on the
terphenyl substituent (i.e., Ni1-C431) amounts to 4.232 Å
(Figure 2). Further, we find the anthryl substituent of complex
8f-pyr similarly twisted against the salicylaldimine plane, given
by, for example, C12-C13-C61-C62 77° (8f-pyr) when
compared to 65° (1a-CH3CN)12 and 80° (1b-PPh3).16b
X-ray diffraction analyses of complexes 7b-pyr and 8f-pyr
exhibit a slightly (tetrahedral) distorted square planar coordina-
tion geometry of the nickel center and confirm a trans-
arrangement of the oxygen atom (O1) and the nickel-bound
methyl group (C1) also in the solid state (Figures 1 and 2).
(22) One reviewer pointed to the possibility that the minor complex
present could be the pyridine-free dimeric species [((κ2-N,O)NiMe)2]. We
cannot totally exclude the reversible formation of the proposed pyridine-
free dimers (as irreversibly observed for (κ2-P,O)-nickel complexes).
However, NMR spectra of single crystals of complex 8f-pyr‚1.5C6H6
obtained by recrystallization exhibit the same isomeric ratio as amorphous
material obtained after solvent-sublimation from synthetic method B, thus
excluding an irreversible formation of such dimer and free pyridine. In
addition, the elemental analysis of complexes 8f-pyr (and somewhat less
convincing 8g-pyr) is in accordance with a higher nitrogen content than
expected for the pyridine-free dimeric structure.

2352 Organometallics, Vol. 26, No. 9, 2007
Go¨ttker-Schnetmann et al.
Figure 2. X-ray diffraction analysis of complex 8f-pyr with 50% probability ellipsoids in two orientations showing the coordination
geometry at nickel (left) and the twisting of terphenyl and anthryl moieties (right). Hydrogen atoms and cocrystallized solvent molecules
are omitted for clarity. Selected bond distances and angles are given in Table 3.
Table 3. Selected Bond Distances and Angles at the Nickel Center in Complexes 7a-pyr, 7b-pyr, 8f-pyr, and 1a-CH3CNa
Ni-N1
[Å]
Ni-O1
[Å]
Ni-C1
[Å]
Ni-N2
[Å]
O1-Ni-N1
N1-Ni-C1
C1-Ni-N2
N2-Ni-O1
[deg]
[deg]
[deg]
[deg]
7b-pyr
1.900(7)
1.897(2)
1.896(3)
1.8872(16)
1.949(7)
1.9051(15)
1.908(3)
1.991(9)
1.936(2)
1.931(4)
1.931(2)
1.890(7)
1.912(2)
1.897(4)
1.8588(19)
92.7(3)
95.3(3)
88.9(3)
85.1(3)
8f-pyr
93.21(7)
92.64(12)
94.12(6)
94.37(10)
96.25(17)
92.88(9)
88.89(10)
87.47(17)
89.07(9)
84.25(8)
83.69(13)
83.87(6)
7a-pyrb
1a-CH3CNc
1.9107(13)
a For the numbering scheme, refer to Figure 1. b Taken from ref 15. c Taken from ref 12.
Table 4. Polymerization Results with Complexes 1a-pyr, 7-pyr, and 8-pyr as Precatalystsa
yield
[g PE]
TON 10-4 × mol [C2H4]
× mol-1 [Ni]
TOF 10-4 × mol [C2H4]
× mol-1 [Ni] × h-1
Tm
[°C]
branches
/1000C
crystallinitye
[%]
f
entry
precatalyst
Mn
Mw/Mn
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1a-pyr
7a-pyrb
8a-pyr
7b-pyr
8b-pyr
7c-pyr
8c-pyr
7d-pyrb
8d-pyr
7e-pyr
8e-pyr
7f-pyrb
8f-pyr
8g-pyr
8.55
7.48
7.97
9.41
12.40
9.85
8.28
6.10
9.16
4.47
4.71
4.50
3.59
4.27
3.1
2.7
2.8
3.6
4.7
3.5
3.0
2.1
3.3
1.7
1.8
1.6
1.3
1.5
4.6
4.0
4.3
5.4
7.1
5.3
4.5
3.3
4.9
2.6
2.7
2.4
1.9
2.3
131
124
117
90
96
92
6c
10c
13c
38c
31c
32c
30c
76d
92
47
50
44
31
32
28
35
200
16
43
11
11
14
16
2.0
3.0
3.0
2.7
2.8
2.0
2.8
2.1
3.9
2.1
2.7
2.5
4.3
5.3
96
1.1
3.2
0.8
0.9
1.9
4.0
81d
88d
79d
80d
78d
10g
a Reaction conditions: 10 µmol of precatalyst, 50 °C, 40 min, 40 bar of ethylene in 100 mL of toluene. b Catalytic activity was reported in ref 15; values
given here differ slightly due to a different polymerization protocol applied here. c Exclusively methyl branches detected by 13C NMR spectroscopy. d >80%
methyl branches by 13C NMR spectroscopy. e Obtained from DSC data on the basis of ∆Hm ) 293 J g-1 for 100% crystallinity. f In 103 g mol-1; obtained
by GPC versus linear polyethylene standards at 160 °C. g Bimodal distribution.
Catalytic Ethylene Polymerization with K2-(N,O)-Salicyl-
aldiminato Nickel(II) Methyl Pyridine Complexes 7a-f-pyr
and 8a-g-pyr. Complexes 7a-f-pyr and 8a-g-pyr as well
as 1a-pyr behave as single component ethylene polymerization
catalysts at temperatures above 15 °C, reaching their highest
productivities in the range between 40 and 75 °C. Probably due
to impurities in the ethylene used (3.5 grade, 99.95% purity),
productivities did not increase linearly with increasing precata-
lyst concentrations at very low precatalyst concentrations. That
is, smaller amounts than 2 µmol of precatalysts, for example,
8a-c-pyr (applied as a freshly prepared stock solution in each
case), did not yield substantial amounts of polyethylenes. Such
effects might be induced by solvent impurities at very low
catalyst loadings. However, polymerization runs using, for
example, 10 µmol of precatalyst 8a-pyr, 50 °C, 40 bar of
ethylene in 200 mL of toluene instead of 100 mL of toluene
result in similar turnover frequencies (4.82 × 104 TO h-1, as
compared to 4.3 × 104 TO h-1, Table 5, entry 2 as compared
to Table 4, entry 3), which underlines the notion that solvent
impurities are not responsible for these activity effects. To obtain
reliable polymerization data without substantial reactor clogging
(e.g., with precatalysts 1a-pyr, 7a-pyr, and 8a-pyr, vide infra),
we have conducted standardized polymerization reactions for
40 min under 40 bar of ethylene at 50 °C using 10 µmol of
catalyst and monitored the ethylene uptake by means of mass-
flow meters. By assuming catalyst-independent saturation kinet-

Nickel(II)-Methyl Pyridine Polymerization Catalysts
Organometallics, Vol. 26, No. 9, 2007 2353
Table 5. Polymerization Results for Catalysts Derived from Terphenylamine 4aa
n[cat]
[µmol]
yield
[g PE]
TOF 104 × mol [C2H4]
× mol-1 [Ni] × h-1
Tm
[°C]
branches
/1000Cb
crystallinityc
[%]
d
entry
precatalyst
Mn
Mw/Mn
1
2
3
4
5
7a-pyr
8a-pyr
9a-pyr
10a-pyr
11a-pyr
16
10
40
20
15
22.6
13.5
11
15
1.50
4.98
4.82
0.98
2.68
0.35
124
117
111
114
114
10
13
15
15
14
50
44
45
49
49
16
43
20
8.5
9.6
3.0
3.0
2.3
2.4
2.2
a Reaction conditions: 50 °C, 60 min, 40 bar of ethylene in 200 mL of toluene. b Exclusively methyl branches detected by 13C NMR spectroscopy.
c Obtained from DSC data on the basis of ∆Hm ) 293 J g-1 for 100% crystallinity. d In 103 g mol-1; obtained by GPC at 160 °C versus linear polyethylene
standards.
Chart 3. K2-(N,O)-Salicylaldiminato Nickel(II) Methyl
Pyridine Complexes Derived from Terphenylamine 4a
ics of the polymerization reaction with respect to [ethylene],23
this procedure enabled (a) comparison of the activity and
stability of anthryl-substituted (1a-pyr and 8a-g-pyr) versus
diiodo-substituted catalysts 7a-f-pyr, and (b) comparison of
the microstructures of the obtained polyethylenes as a function
of the precatalyst (Table 4).
Notably, while anthryl-substituted complex 8b-pyr is the most
active precatalyst under these polymerization conditions (TOF
ca. 71.000 TO h-1, entry 5), all diiodo-substituted complexes
7-pyr perform similarly well when compared to the respective
anthryl-substituted complexes 8-pyr, and to 1a-pyr. Further,
the anthryl versus diiodo substitution does not exert a major
even though the distance of these groups to the nickel center is
quite high (vide supra).
influence on the degree of branching of the obtained polyeth-
ylenes.
As already stated, the degree of branching of the polyethyl-
enes obtained with complexes 7-pyr and 8-pyr is mainly
insensitive to the substitution of the salicyl-ring and highly
sensitive to the respective terphenyl substituent (vide supra). If
this observation holds true in general, complexes 9a-11a-pyr
(for details, see experimental part) derived from terphenylamine
4a should produce polyethylenes with a microstructure similar
to that of 7a-pyr, 8a-pyr, despite the variety of stereoelectronic
modifications exerted, for example, by the o-H and p-NO2 versus
o-tBu and p-H substituents in 10a-pyr and 11a-pyr (Chart 3).
Polymerization results with these complexes are summarized
in Table 5 and confirm the more general notion that it is the
terphenyl substituent in these catalysts that exclusively controls
the degree of branching.
Under the conditions studied here (50 °C; reaction times of
40-120 min), all catalysts are quite stable. In more detail,
complexes 1a-pyr and 7a-11a-pyr derived from 2,6-diisopro-
pylaniline or terphenylamine 4a appear to exhibit constant
polymerization activities over time as evidenced by the respec-
tive mass-flow traces (for details, see Supporting Information)
and polymer yields in 40- and 60-min (and for 7a-pyr: 120
min) polymerization runs. Further, complexes 7b,c-pyr, 8b,c-
pyr show a slight decrease in polymerization activity over time
reaching one-half of the initial activity after ca. 1.5-2.0 h, while
one-half of the initial activities after ca. 1 h were observed with
complexes 7d-f-pyr, 8d-g-pyr. At 70 °C, the decrease in
polymerization activities over time is more pronounced as
evidenced by the mass-flow traces of, for example, polymeriza-
tions with precatalyst 8b,c-pyr (Supporting Information).
In contrast, and as already found for complexes 7a-,7d-,7f-
pyr, the degree of branching of obtained polyethylenes is highly
sensitive to the 3′,5′-substitution pattern of the terminal arene
rings of the terphenyl moieties in both complexes 7-pyr and
8-pyr. As these 3′,5′-substituents appear to be far away from
the catalytically active nickel center (vide supra, Figures 1 and
2 and ref 15), we had suggested earlier for complexes 7a-,d-
,f-pyr that the microstructure control exerted by these substit-
uents is more electronic than steric in nature.15 That is, more
electron-deficient N-aryl substituents result in higher molecular
weights and lower degrees of branching supposedly by sup-
pressing chain walking and chain transfer relative to ethylene
insertion. To further probe this hypothesis, complexes 7b-,7c-
pyr, 8b-,8c-pyr, containing tert-butyl substituents (even bulkier
than the CF3-groups in 7a-pyr and 8a-pyr) with properties
electronically similar to those of the methyl-substituted com-
plexes 7d-pyr and 8d-pyr, have been prepared for this study.
These complexes, however, produce polyethylenes with (a)
significantly higher molecular weight (e.g., 7b-pyr: Mn ) 11
× 103 g mol-1) and less branching (e.g., 7b-pyr: 38 methyl
branches per 1000 carbon atoms) than that obtained with 7d-
pyr (Mn ) 1.1 × 103 g mol-1, 66 methyl-, 4 ethyl-, 6 C4+
-
branches per 1000 carbon atoms) or 8d-pyr (Mn ) 3.2 × 103
g mol-1, 72 methyl-, 6 ethyl- 14 C4+-branches), and (b)
significantly higher degree of branching than that obtained with
complexes 7a-pyr (10 methyl branches per 1000 carbon atoms)
or 8a-pyr (13 methyl branches per 1000 carbon atoms).
Therefore, it seems that, in addition to an increased electron-
withdrawing character of the 3′,5′-substituents, sterically more
demanding 3′,5′-substituents also favor the formation of higher
molecular weight polyethylenes with low branching content,
While, in principle, mass transfer limitations due to copre-
cipitation of the catalyst with the formed polyethylene may result
in decreasing ethylene consumption, we note here that only in
case of catalysts derived from 2,6-diisopropylaniline or ter-
phenylamine 4a (i.e., 1a-pyr, 7a-11a-pyr) were substantial
amounts of precipitated polyethylene present in the crude reac-
tion mixture, while reaction mixtures obtained with complexes
7d-f-pyr and 8d-g-pyr remained homogeneous throughout
the polymerization. We therefore conclude that the positive
effect of the anthryl substituent in complexes 1a-L on the long-
(23) The kinetic order of the catalysts under investigation with respect
to ethylene is likely 0th order in ethylene at 40 bar. We have not conducted
systematic studies with respect to the order in ethylene, but we have observed
that for exemplified catalysts (7a-pyr, 8a-pyr, and 8f-pyr) low ethylene
pressures (20, 10, and 5 bar of ethylene) result in increasingly lower
activities, while ethylene pressures >30 bar result in saturation behavior.
Polymerization conditions studied here were intended to compare activities
and polymer microstructures under identical reaction conditions, that is,
including saturation behavior.

2354 Organometallics, Vol. 26, No. 9, 2007
Go¨ttker-Schnetmann et al.
prepared in analogy to a known procedure.25 Column chromatog-
raphy: Merck silica gel 60. TLC: Merck silica gel 60F254 plates.
Rf-values refer to TLC tests. NMR spectra were recorded on a
term stability does not hold in general when the anthryl
substituent is combined with terphenyl substituents as in
complexes 8-pyr. Following the rational given by Grubbs et
al.,12 that the anthryl substituent of complexes 1a-L suppresses
the formation of catalytically inactive bis[(κ2-N,O)-salicylaldi-
minato]nickel complexes due to its bulkiness, and considering
similarly sterically congested situations for the bis-chelation of
salicylaldimines 6a-g (i.e., bearing anthryl and terphenyl
substituents) by nickel(II), we believe that a different decom-
position mechanism might be operative for complexes 8-pyr
when compared to complexes 1a-L.
1
Varian Inova 400 or a Bruker Avance DRX 600 instrument. H
chemical shifts were referenced to residual protiated solvent. 13C
chemical shifts were referenced to deuterated solvents. The assign-
ment of chemical shifts for new salicylaldimines and complexes is
based on 1H, 1H,1H-gCOSY, 13C{1H}, DEPT135, 1H,13C-gHMQC,
1
and H,13C-gHMBC NMR experiments. Elemental analyses were
carried out at the Department of Chemistry at the University of
Konstanz. Polymerization reactions were conducted in a 300 mL
Bu¨chi miniclave equipped with a heating/cooling jacket supplied
by a thermostat controlled by a thermocouple dipping into the
polymerization mixture. Ethylene uptake of the autoclave was
monitored via Bronkhorst mass-flow meters. Ethylene of 3.5 grade
supplied by Gerling Holz + Co. was used without further
purification. Molecular weights of obtained polyethylenes were
determined by NMR analyses or GPC versus linear polyethylene
standards on a PL220 instrument equipped with mixed B columns
using trichlorobenzene/0.0125% BHT at 160 °C. 1H and 13C NMR
analyses of obtained polyethylenes were conducted in 1,1,2,2-
tetrachloroethane-d2 at 130 °C. Integration of 13C NMR spectra is
based on inverse gated decoupled experiments with an acquisition
time of ca. 1.2 s and a relaxation delay of 1 s in the presence of
0.5 wt % Cr(acac)3 as relaxation aid. Differential scanning
calorimetry (DSC) of obtained polymers was measured on a Netzsch
DSC 204 F1 with a heating/cooling rate of 10 °C min-1. DSC data
reported are from second heating cycles.
General Procedure for the Preparation of Terphenylamines
(4a-g). To a mixture of 2,6-dibromoaniline, 2.3 equiv of the
respective aryl boronic acid, 1 mol % Pd(dba)2, and 2.1 mol %
PPh3 in an argon-filled Schlenk flask was added toluene (1.5 mL
per mmol boronic acid). The suspension was stirred at 25 °C until
the initially purple suspension turned orange (ca. 10 min), ethanol/
water (1:1) (0.5 mL per mmol boronic acid) and 4 equiv of
Na2CO3 were added, and the suspension was heated to 95 °C
with vigorous stirring for 10-48 h. The resulting biphasic mixture
was stirred for 30-60 min under air (resulting in formation of
palladium black) and poured into a separatory funnel, and water
and diethyl ether were added until all salts and organic material
dissolved. The organic layer was separated (and filtrated through a
plug of celite to remove Pd black), the aqueous phase was extracted
with additional 2 × 25 mL of diethyl ether, and the combined
organic phases were concentrated under reduced pressure (35 °C,
650 mbar, then 20 mbar). Analytically pure terphenylamines
4a-g were obtained after column chromatography of the residues
on silica. Analytical data of terphenylamines 4a,d,f are given in
ref 15.
Summary and Conclusion
A new high yield synthesis of (κ2-N,O)salicylaldiminato
nickel methyl complexes 1a-pyr, 7-pyr, and 8-pyr from
salicylaldimines 5a-f, 6a-g and [(pyridine)2Ni(CH3)2] has been
presented. Complexes 7-pyr and 8-pyr were studied in the
polymerization of ethylene and proved to be highly active with
turnover frequencies as high as ca. 71.000 mol ethylene mol-1
[Ni] h-1 at 50 °C, 40 bar of ethylene. Anthryl-substituted
complexes 1a-pyr and 8-pyr exhibit polymerization activities
similar to those of complexes 7-pyr derived from 3,5-diio-
dosalicylaldehyde. Independent of the stereoelectronic modifica-
tion of the salicyl-ring, the 3′,5′-substitution of the terphenyl
group has a major impact on the polyethylene microstructure.
Electron-withdrawing as well as sterically demanding 3′,5′-
substituents decrease the degree of branching (and increase
molecular weight) in the obtained polyethylenes as compared
to electron-donating and small substituents. Complexes 1a-pyr
and 7a-11a-pyr derived from terphenylamine 4a are highly
stable polymerization catalysts, while all other complexes 7-pyr
and 8-pyr slowly deactivate under the reaction conditions
studied.
Experimental Section
General Considerations and Materials. All manipulations of
air- and moisture-sensitive substances were carried out using
standard Schlenk, vacuum, and glovebox techniques under argon
or nitrogen. Pentane and dichloromethane were distilled from
calcium hydride, benzene and toluene from sodium, and diethyl
ether and THF from blue sodium benzophenone ketyl under argon
prior to use. Pyridine and triethylamine were deoxygenated, distilled
from potassium hydroxide, and stored in Rotaflo-flasks prior to
use. Petrol ether (bp 55-85 °C) for column chromatography was
distilled once by rotavap to remove high boiling impurities. All
other solvents were commercial grade. 2-Bromoanisole, anthrone,
BBr3, 1,2-dibromoethane, 2,6-dibromoaniline, 3,5-diiodosalicyl-
aldehyde, 3-(tert-butyl)salicylaldehyde, and 5-nitrosalicyladehyde
were used as received from Aldrich. Paraformaldehyde was dried
over P2O5 prior to use. 3,5-Bis[3,5-bis(trifluoromethyl)-phenyl]-
salicylaldehyde and complex 9a-pyr were prepared according to
known procedures.24 [(tmeda)Ni(CH3)2]18 was purchased from MCat
and stored at -30 °C in a glovebox prior to use. [(pyridine)2Ni-
(CH3)2]19 was synthesized by a modified literature procedure and
stored at -30 °C in a glovebox prior to use. Terphenylamines 4a,d,f
were synthesized in analogy to ref 15. Salicylaldimines 5a,d,f
described in ref 15 were obtained in improved yield using the
general procedure described here. Terphenylamine 4c and salicyl-
aldimines 5c,6c were synthesized according to ref 9. Boronic acids
were synthesized in analogy to known standard procedures except
for 3,5-di(tert-butyl)-4-hydroxyphenyl boronic acid, which was
2,6-Bis[3,5-di(tert-butyl)phenyl]aniline (4b). Following the
general procedure, 1.64 g (3.49 mmol, 87%) of 2,6-bis[3,5-di(tert-
butyl)phenyl]aniline (4b) was obtained from 2,6-dibromoaniline
(1.004 g, 4 mmol), 3,5-di(tert-butyl)phenylboronic acid (2.155 g,
9.2 mmol), Pd(dba)2 (23 mg, 41 µmol), PPh3 (22.6 mg, 86 µmol),
and Na2CO3 (1.70 g, 16 mmol) as a white solid after 16 h at 95 °C
and column chromatography using petrol ether/toluene (30:1, Rf )
0.2) as eluent. 1H NMR (399.8 MHz, C6D6, 25 °C): δ 7.55 (s, 6H,
3
2 × 8-, 10-, and 12-H), 7.31 (d, JHH ) 7.6 Hz, 2H, 3- and 5-H),
6.91 (t, 3JHH ) 7.6 Hz, 1H, 4-H), 3.79 (s, 2H, NH2), 1.30 (s, 36H,
(24) Wehrmann, P.; Zuideveld, M.; Thomann, R.; Mecking, S. Macro-
molecules 2006, 39, 5995-6002.
(25) Irlapati, N. R.; Baldwin, J. E.; Adlington, R. M.; Pritchard, G. J.
Org. Lett. 2003, 5, 2351-2354.

Nickel(II)-Methyl Pyridine Polymerization Catalysts
Organometallics, Vol. 26, No. 9, 2007 2355
t
4 × Bu). 13C{1H} NMR (100.5 MHz, C6D6, 25 °C): δ 151.5 (Cq,
(1.951 g, 9.2 mmol), Pd(dba)2 (23 mg, 41 µmol), PPh3 (22.6 mg,
86 µmol), and Na2CO3 (1.70 g, 16 mmol) as a white solid after 34
h at 95 °C and column chromatography using petrol ether (PE)/
diethyl ether (E) (3:1) as eluent [Rf ) 0.3 (PE/E ) 3:1)]. Substantial
amounts of homocoupling product were also isolated. 4g, 1H NMR
(399.8 MHz, CDCl3, 25 °C): δ 7.15 (d, 3JHH ) 7.6 Hz, 2H, 3- and
2 × C9 and C11), 141.7 (Cq, C1), 140.2 (Cq, 2 × C7), 130.1 (CH,
C3 and C5), 129.2 (Cq, C2 and C6), 124.1 (CH, 2 × C8 and C12),
t
121.1 (CH, 2 × C10), 118.5 (CH, C4), 35.0 (Cq, 4 × Bu), 31.6
(CH3, 4 × Bu). Anal. Calcd for C34H47N (469.74 g mol-1): C,
t
86.93; H, 10.08; N, 2.98. Found: C, 86.77; H, 9.82; N, 3.18.
3
5-H), 6.88 (t, JHH ) 7.6 Hz, 1H, 4-H), 6.72 (s, 4H, 2 × 8- and
12-H), 3.91 (s, 6H, 2 × 10-OCH3), 3.89 (s, 12H, 2 × 9- and 11-
OCH3). 13C{1H} NMR (100.5 MHz, CDCl3, 25 °C): δ 153.4 (Cq,
2 × C9 and C11), 140.6 (Cq, C1), 137.1 (Cq, 2 × C10), 135.1 (Cq,
2 × C7), 129.5 (CH, C3 and C5), 127.9 (Cq, C2 and C6), 117.9
(CH, C4), 106.2 (CH, 2 × C8 and C12), 60.9 (CH3, 2 × 10-OCH3),
56.1 (CH3, 2 × 9- and 11-OCH3). Anal. Calcd for C24H27NO6
(425.47 g mol-1): C, 67.75; H, 6.40; N, 3.29. Found: C, 68.00;
H, 6.76; N, 3.08.
2,6-Bis[3,5-di(tert-butyl)-4-hydroxyphenyl]aniline (4c). Fol-
lowing the general procedure, 1.631 g (3.25 mmol, 81%) of 2,6-
bis[3,5-di(tert-butyl)-4-hydroxyphenyl]aniline (4c) was obtained
from 2,6-dibromoaniline (1.004 g, 4 mmol), 3,5-di(tert-butyl)-4-
hydroxyphenylboronic acid (2.300 g, 9.2 mmol), Pd(dba)2 (23 mg,
41 µmol), PPh3 (22.6 mg, 86 µmol), and Na2CO3 (1.70 g, 16 mmol)
as an off-white solid after 20 h at 95 °C and column chromatography
using petrol ether/toluene (10:1) as eluent [Rf ) 0.2 (PE/E )
4:1)]. 1H NMR (399.8 MHz, C6D6, 25 °C): δ 7.52 (s, 4H, 2 × 8-
3
3
and 12-H), 7.30 (d, JHH ) 7.6 Hz, 2H, 3- and 5-H), 6.91 (t, JHH
) 7.6 Hz, 1H, 4-H), 4.99 (s, 2H, 2 × OH), 3.82 (s, 2H, NH2), 1.36
2-(9-Anthryl)anisol. A 500 mL three-neck flask equipped with
a reflux condenser and a 250 mL dropping funnel was charged
with magnesium turnings (1.340 g, 55.1 mmol) under argon. THF
(3 mL) and 1,2-dibromoethane (100 mg) were added by syringe,
and the mixture was allowed to stand for ca. 5 min without stirring
until evolution of ethylene was observed. A solution of 2-bro-
moanisole (9.352 g, 50 mmol) in THF (120 mL) was carefully
added over 45 min under gentle reflux with no heating. The mixture
was stirred for an additional 30 min and cooled to -20 °C
(isopropanol/dry ice). A solution of anthrone (9.715 g, 50 mmol)
in 200 mL of THF/toluene (1:1) was added over 30 min under
vigorous stirring. The resulting mixture was allowed to warm to
20 °C, stirred for an additional 30 min, and poured into 100 mL of
ice-cold 3 N HCl. The mixture was stirred for 60 min. After phase
separation, the aqueous phase was extracted with 2 × 30 mL of
toluene, and the combined organic (and acidic) phases were
concentrated to dryness. The resulting residue was recrystallized
from boiling methanol to give 13.30 g (46.8 mmol, 93.5%) of 2-(9-
anthryl)anisol as a pale yellowish solid.
2-(9-Anthryl)phenol. To a solution of 2-(9-anthryl)anisol (5.707
g, 20 mmol), tetrabutylammonium iodide (12.91 g, 33 mmol), and
60 mL of dry dichloromethane in a 250 mL Schlenk tube was added
a solution of BBr3 (6.263 g, 25 mmol) in 5 mL of dichloromethane
within 5 min at -78 °C (isopropanol/dry ice). The cooling bath
was removed, and the solution was stirred for 40 h at 20 °C. After
careful addition of 5 mL of methanol (30 min), the resulting mixture
was extracted with 4 × 50 mL of water. The organic phase was
concentrated to dryness, and the resulting solid was dispersed in 5
mL of ethanol under sonication, filtrated, and washed with 2 × 2
mL of cold methanol to leave 4.925 g (18.2 mmol, 91.1%) of 2-(9-
anthryl)phenol as a pale yellow solid after removal of residual
solvent under high vacuum (10-3 mbar).
2-Hydroxy-3-(9-anthryl)benzaldehyde‚1/2CH2Cl2 (3b). To a
mixture of magnesium turnings (1.10 g, 45 mmol) and 5 mL of
diethyl ether in a 500 mL Schlenk tube connected to a 100 mL
dropping funnel with pressure release was added a solution of 1,2-
dibromoethane (9.400 g, 50 mmol) in 80 mL of diethyl ether over
90 min and gentle reflux (Caution: ethylene evolution). The mixture
was stirred until all magnesium dissolved, the dropping funnel was
replaced by a septum, and the solvent and remaining 1,2-
dibromoethane were removed under vacuum (20 °C, 10-3 mbar,
then 60 min, 100 °C, 10-3 mbar). To the freshly prepared MgBr2‚
(Et2O)n were added solid 2-(9-anthryl)phenol (4.900 g, 18.1 mmol),
paraformaldehyde (1.522 g, 50.7 mmol), and finally 150 mL of
toluene. The resulting mixture was stirred with a high mass stirring
(s, 36H, 4 × Bu). 13C{1H} NMR (100.5 MHz, C6D6, 25 °C): δ
t
153.4 (Cq, 2 × C10), 142.1 (Cq, C1), 136.5 Cq, 2 × C9 and C11),
132.1 (Cq, 2 × C7), 129.9 (CH, C3 and C5), 129.2 (Cq, C2 and
C6), 126.5 (CH, 2 × C8 and C12), 118.5 (CH, C4), 34.5 (Cq, 4 ×
tBu), 30.4 (CH3, 4 × Bu). Anal. Calcd for C34H47NO2 (501.74 g
t
mol-1): C, 81.39; H, 9.44; N, 2.79. Found: C, 80.99; H, 9.62; N,
2.90.
2,6-(4-Methoxy-3,5-dimethylphenyl)aniline (4e). Following the
general procedure, 526 mg (1,46 mmol, 73%) of 2,6-bis(4-methoxy-
3,5-dimethyphenyl)aniline (4e) was obtained from 2,6-dibromo-
aniline (500.2 mg, 2 mmol), 4-methoxy-3,5-dimethylphenylboronic
acid (830 mg, 4.6 mmol), Pd(dba)2 (12 mg, 21 µmol), PPh3 (12
mg, 46 µmol), and Na2CO3 (848 mg, 8 mmol) as an off-white solid
after 34 h at 95 °C and column chromatography using petrol ether
(PE)/diethyl ether (E) (3:1) as eluent [Rf ) 0.5 (PE/E ) 3:1)].
Substantial amounts of homocoupling product were also isolated.
1H NMR (399.8 MHz, CDCl3, 25 °C): δ 7.17 (s, 4H, 2 × 8- and
12-H), 7.09 (d, 3JHH ) 7.9 Hz, 2H, 3- and 5-H), 6.85 (t, 3JHH ) 7.9
Hz, 1H, 4-H), 3.90 (s br, 2 H, NH2), 3.80 (s, 6H, 2 × OCH3), 2.36
(s, 12H, 2 × 9- and 11-CH3). 13C{1H} NMR (100.5 MHz, CDCl3,
25 °C): δ 156.2 (Cq, 2 × C10), 140.7 (Cq, C1), 135.2 and 127.8
(Cq each, C2, C6, and 2 × C7), 131.2 (Cq, C9 and C11), 129.6
(CH, 2 × C8 and C12), 129.3 (CH, C3 and C5), 118.0 (CH, C4),
59.7 (CH3, 2 × 10-OCH3), 16.1 (CH3, 2 × 9- and 11-CH3). Anal.
Calcd for C24H27NO2 (361.48 g mol-1): C, 75.79; H, 7.53; N, 3.87.
Found: C, 76.00; H, 7.80; N, 3.54.
2,6-Bis(3,4,5-trimethoxyphenyl)aniline (4g). Following the
general procedure, 1.203 g (2.83 mmol, 71%) of 2,6-bis(3,4,5-
trimethoxyphenyl)aniline (4g) was obtained from 2,6-dibromo-
aniline (1.004 g, 4 mmol), 3,4,5-trimethoxyphenylboronic acid

2356 Organometallics, Vol. 26, No. 9, 2007
Go¨ttker-Schnetmann et al.
t
t
bar (alternatively a mechanical stirrer may be used) for 10 min at
20 °C, triethylamine (3.542 g, 35 mmol) was added by syringe
while color change from pale yellow to orange was observed, and
slowly heated to 80 °C under vigorous stirring, while the dis-
persed solids became sticky. After 120 min at 80 °C, a TLC test
indicated consumption of the starting phenol. The organic phase
was decanted and evaporated to ca. 25 mL (55 °C, 20 mbar),
and the resulting mixture was cooled to 20 °C, poured into 200
mL of 1 N HCl, stirred for 20 min, and finally extracted with di-
ethyl ether (4 × 50 mL). The combined organic phases were
dried over Na2SO4 and concentrated to dryness (20-80 °C,
650-20 mbar). The crude product thus obtained (5.31 g) was
dissolved in the minimum amount of boiling dichloromethane (ca.
7-8 mL) and allowed to slowly cool to 20 °C. The resulting
solution was carefully layered with 10 mL of methanol and allowed
to stand for 1 d at +5 °C after which 4.465 g (13.10 mmol,
72.4%) analytically pure crystals of 2-hydroxy-3-(9-anthryl)-
benzaldehyde‚1/2CH2Cl2 (3b) had deposited. Repeated crystalliza-
tion from the mother liquor yielded another crop of 0.42 g (1.23
mmol, 6.8%) of compound 3b (combined yield: 79.2%). 1H
NMR (399.8 MHz, C6D6, 25 °C): δ 11.57 (s, 1H, OH), 9.28 (s,
1H, 7-H), 8.24 (s, 1H, 15-H), 7.83 and 7.73 (m each, 2H each,
10-, 13-, 17-, and 20-H), 7.24 and 7.16 (m each, 2H and 3H, 11-,
C5), 79.1 (Cq, C3), 34.8 (Cq, 4 × Bu), 31.4 (CH3, 4 × Bu). Anal.
Calcd for C41H49NOI2 (825.64 g mol-1): C, 59.64; H, 5.98; N,
1.70. Found: C, 60.00; H, 6.31; N, 1.40.
Salicylaldimine 5e. Following the general procedure, 811 mg
(1.13 mmol, 94%) of compound 5e was obtained after 12 h as an
1
orange powder. H NMR (399.8 MHz, C6D6, 25 °C): δ 13.98 (s
br, 1H, OH), 7.71 (d, 4JHH ) 1.9 Hz, 1H, 4-H), 7.32 (d, 3JHH ) 7.7
3
Hz, 2H, 10- and 12-H), 7.30 (s, 1H, 7-H), 7.12 (t, JHH ) 7.7 Hz,
1H, 11-H), 7.04 (s, 4H, 15-, 19-, 21-, and 25-H), 6.57 (d, JHH
4
)
1.9 Hz, 1H, 6-H), 3.36 (s, 6H, 2 × OCH3), 2.17 (s, 12H, 4 × CH3).
13C{1H} NMR (100.5 MHz, C6D6, 25 °C): δ 166.3 (CH, C7), 160.3
(Cq, C2), 156.9 (Cq, C17 and C23), 149.0 (CH, C4), 144.6 (Cq,
C8), 140.1 (CH, C6), 135.4 and 135.0 (Cq each, C9, C13, C14,
and C20), 131.2 (Cq, C16, C18, C22, and C24), 130.6 (CH, C15,
C19, C21, and C25), 130.1 (CH, C10 and C12), 126.5 (CH, C11),
120.5 (Cq, C1), 87.4 (Cq, C5), 79.8 (Cq, C3), 59.3 (CH3, 2 × OCH3),
16.2 (CH3, 16-, 18-, 22-, and 24-CH3). Anal. Calcd for C31H29-
NO3I2 (717.38 g mol-1): C, 51.90; H, 4.07; N, 1.95. Found: C,
52.11; H, 4.48; N, 1.75.
3
4
12-, 18-, 19-, and 4-H), 6.88 (dd, JHH ) 7.8 Hz and JHH ) 1.9
Hz, 1H, 6-H), 6.63 (vt, JHH ) 7.8 Hz, 1H, 5-H). 13C{1H} NMR
(100.5 MHz, C6D6, 25 °C): δ 196.6 (CH, C7), 160.4 (Cq, C2),
140.1 (CH, C4), 133.7 (CH, C6), 132.0 and 131.0 (Cq each, C9,
C14, C16, and C21), 131.6 (Cq, C8), 129.0 and 126.6 (CH each,
C10, C13, C17, and C20), 127.9 (Cq, C3) 127.8 (CH, C15), 125.9
and 125.3 (CH each, C11, C12, C18, and C19), 121.1 (Cq, C1),
119.6 (CH, C5).
General Procedure for the Preparation of Salicylaldimines
5a-f, 6a-g. Unless otherwise noted, the following general
procedure gave satisfactory results: To a mixture of 1.2 mmol of
the respective salicylaldehyde 3a,b, 1.2 mmol of the respective
terphenylamine 4a-g, and 5 mg of p-toluene sulfonic acid hydrate
in a 50 mL flask was added 15 mL of methanol. The suspension
was heated to 60 °C for 30-120 min while all starting materials
dissolved, then sonicated at 25 °C for 5 min to facilitate precipitation
of the product, and stirred for 12-18 h at 25 °C. The resulting
suspension was cooled to 0 °C and filtrated, and the residue was
washed with 3 × 3 mL of cold methanol (0 °C) and dried in vacuum
(10-3 mbar) to yield analytically pure samples.
Salicylaldimine 6b. Following the general procedure, 834 mg
(1.11 mmol, 93%) of compound 6b was obtained after 14 h as a
pale yellow powder. 1H NMR (399.8 MHz, C6D6, 25 °C): δ 12.96
(s br, 1H, OH), 8.20 (s, 1H, 33-H), 7.85 (s, 1H, 7-H), 7.84 and
3
7.78 (m each, 2H each, 28-, 31-, 35- and 38-H), 7.46 (d, JHH
)
7.6 Hz, 2H, 10- and 12-H), 7.39 (s, 6H, 15-, 17-, 19-, 21-, 23- and
3
25-H), 7.29 (m, 4H, 29-, 30-, 36- and 37-H), 7.15 (t, JHH ) 7.6
3
4
Hz, 1H, 11-H), 7.02 (dd, JHH ) 8.0 Hz and JHH ) 2.0 Hz, 1H,
3
4
4-H), 6.60 (dd, JHH ) 8.0 Hz and JHH ) 2.0 Hz, 1H, 6-H), 6.52
(t, (dd, JHH ) 8.0, 1H, 5-H), 1.19 (s, 36H, 4 × Bu). 13C{1H} NMR
t
(100.5 MHz, C6D6, 25 °C): δ 169.3 (CH, C7), 160.0 (Cq, C2),
150.9 (Cq, C16, C18, C22, and C24), 145.9 (Cq, C8), 139.5 and
136.5 (Cq each, C9, C13, C14, and C20), 136.4 (CH, C4), 133.3
(Cq, C26), 132.0 and 131.0 (Cq each, C27, C32, C34, and C39),
132.0 (CH, C6), 130.4 (CH, C10 and C12), 128.8 and 127.5 (CH
each, C28, C31, C35, and C38), 127.3 (Cq, C33), 127.1 (Cq, C3),
126.1 (CH, C11), 125.3 and 125 (CH each, C29, C30, C36, and
C37), 124.8 (CH, C15, C19, C21, and C25), 121.0 (CH, C17 and
Salicylaldimine 5b. Following the general procedure, 824 mg
(1.00 mmol, 83%) of compound 5b was obtained after 14 h,
concentration of the reaction mixture to ca. 5 mL (70 °C, 1 bar),
1
and crystallization as a pale orange powder. H NMR (600 MHz,
4
t
CDCl3, 25 °C): δ 13.85 (s br, 1H, OH), 7.93 (d, JHH ) 1.9 Hz,
C23), 119.5 (Cq, C1), 118.4 (CH, C5), 34.9 (Cq, 4 × Bu), 31.5
3
t
1H, 4-H), 7.70 (s, 1H, 7-H), 7.48 (d, JHH ) 7.8 Hz, 2H, 10- and
(CH3, 4 × Bu). Anal. Calcd for C55H59NO (750.06 g mol-1): C,
3
12-H), 7.40 (t, JHH ) 7.8 Hz, 1H, 11-H), 7.33 (s, 2H, 17- and
88.07; H, 7.93; N, 1.87. Found: C, 87.61; H, 8.28; N, 1.70.
Salicylaldimine 6d. Following the general procedure, 602 mg
(1.03 mmol, 86%) of compound 6d was obtained after 12 h as a
pale yellow powder. 1H NMR (399.8 MHz, C6D6, 25 °C): δ 13.17
(s, 1H, OH), 8.23 (s, 1H, 33-H), 7.87 and 7.81 (m each, 2H each,
4
23-H), 7.18 (s, 4H, 15-, 19-, 21-, and 25-H), 6.92 (d, JHH ) 1.9
t
Hz, 1H, 6-H), 1.25 (s, 36H, 4 × Bu). 13C{1H} NMR (150 MHz,
CDCl3, 25 °C): δ 166.3 (Cq, C7), 159.9 (Cq, C2), 150.8 (Cq, C16,
C18, C22, and C24), 148.6 (CH, C4), 143.9 (Cq, C8), 139.8 (CH,
C6), 138.1 and 135.9 (Cq each, C9, C13, C14, and C20), 129.9
(CH, C10 and C12), 126.3 (CH, C11), 124.3 (CH, C15, C19, C21,
and C25), 121.1 (CH, C17 and C23), 120.4 (Cq, C1), 86.7 (Cq,
3
28-, 31-, 35-, and 38-H), 7.85 (s, 1H, 7-H), 7.35 (d, JHH ) 7.9
Hz, 2H, 10- and 12-H), 7.26 (m 4H, 29-, 30-, 36-, and 37-H), 7.12
(t, JHH ) 7.9 Hz, 1H, 11-H), 7.05 (s, 4H, 15-, 19-, 21-, and 25-
3

Nickel(II)-Methyl Pyridine Polymerization Catalysts
Organometallics, Vol. 26, No. 9, 2007 2357
(<60% by NMR) even after prolongated reaction times. However,
6f was obtained by the following procedure: A solution of
2-hydroxy-3-(9-anthryl)benzaldehyde‚1/2CH2Cl2 (3b) (409 mg, 1.2
mmol) and 2,6-bis(3,5-dimethoxyphenyl)aniline (364 mg, 1.2 mmol)
in 60 mL of toluene was refluxed for 6 h with a Dean-Starck
apparatus (150 °C bath temperature). The solvent was removed
under reduced pressure (50 °C, 300 to 20 mbar), 10 mL of methanol
was added, and the resulting mixture was sonicated for 30 min.
The resulting pale yellow solid was collected by filtration, washed
with small portions of cold methanol (0 °C), and dried in a vacuum
to yield 601 mg (0.93 mmol, 78%). 1H NMR (95:5 mixture of two
isomers, main isomer reported) (399.8 MHz, C6D6, 25 °C): δ 13.41
(s, 1H, OH), 8.23 (s, 1H, 33-H), 7.84 (vd, J ) 8.0 Hz, 2H, 28- and
38-H), 7.81 (s, 1H, 7-H), 7.75 (vd, J ) 8.0 Hz, 31- and 35-H),
7.37 (d, 3JHH ) 7.8 Hz, 2H, 10- and 12-H), 7.26 (m, 4H, 29-, 30-,
36-, and 37-H), 7.05 (m, 2H, 11-H and 4-H), 6.71 (s, 4H, 15-, 19-,
21-, and 25-H), 6.63 (m, 1H, 6-H), 6.53 (m, 1H, 5-H), 6.46 (s, 2H,
17- and 23-H), 3.26 (s, 12H, 4 × OCH3). 13C{1H} NMR (100.5
MHz, C6D6, 25 °C): δ 168.4 (CH, C7), 161.3 (Cq, C16, C18, C22,
and C24), 160.0 (Cq, C2), 145.8 (Cq, C8), 141.7 (Cq each, C9 and
C13), 136.6 (CH, C4), 135.2 (Cq, C14 and C20), 133.2 and 127.1
(Cq each, C3 and C26), 132.4 (CH, C6), 132.0 and 131.1 (Cq each,
C27, C32, C34, and C39), 130.2 (CH, C31 and C35), 128.8 (CH,
C28 and C38), 127.3 (CH, C33), 127.1 (CH, C10 and C12), 126.2
(CH, C11), 125.6 and 125.2 (CH each, C29, C30, C36, and C37),
119.3 (Cq, C1), 118.9 (CH, C5), 108.1 (CH, C15, C19, C21, and
C25), 100.5 (CH, C17 and C23), 55.0 (CH3, 4 × OCH3). Anal.
Calcd for C43H35NO5 (645.74 g mol-1): C, 79.98; H, 5.46; N, 2.17.
Found: C, 79.13; H, 5.66; N, 1.87.
H), 7.04 (dd, 3JHH ) 7.9 and 4JHH ) 1.9 Hz, 1H, 4-H), 6.64 (s, 2H,
17- and 23-H), 6.60 (dd, 3JHH ) 7.9 and 4JHH ) 1.9 Hz, 1H, 6-H),
3
6.52 (vt, JHH ) 7.9, 1H, 5-H), 2.16 (s, 12 H, 4 × CH3). 13C{1H}
NMR (100.5 MHz, C6D6, 25 °C): δ 168.5 (CH, C7), 160.1 (Cq,
C2), 145.9 (Cq, C8), 139.7 and 135.4 (Cq each, C9, C13, C14, and
C20), 137.7 (Cq, C16, C18, C22, and C24), 136.3 (CH, C15, C19,
C21, and C25), 133.5 (Cq, C26), 132.2 (CH, C6), 132.1 and 131.1
(Cq each, C27, C32, C34, and C39), 130.1 (CH, C10 and C12),
128.9 (CH, C17 and C23), 128.8 and 127.2 (CH, C28, C31, C35,
and C39), 128.2 (CH, C15, C19, C21, and C25), 127.3 (CH, C33),
127.1 (Cq, C3), 126.0 (CH, C11), 125.4 and 125.1 (CH each, C29,
C30, C36, and C37), 119.2 (Cq, C1), 118.6 (CH, C5), 21.2 (CH3,
16-, 18-, 22-, and 24-CH3). Anal. Calcd for C43H35NO (581.74 g
mol-1): C, 88.78; H, 6.06; N, 2.41. Found: C, 88.31; H, 5.78; N,
2.10.
Salicylaldimine 6e. Following the general procedure, 688 mg
(1.07 mmol, 89%) of compound 6e was obtained after 18 h as a
pale yellow powder. 1H NMR (399.8 MHz, C6D6, 25 °C): δ 13.14
(s, 1H, OH), 8.24 (s, 1H, 33-H), 7.89 (s, 1H, 7-H), 7.85 and 7.79
3
(m each, 2H each, 28-, 31-, 35-, and 38-H), 7.35 (d, JHH ) 7.8
Salicylaldimine 6g. Following the general procedure, 797 mg
(1.13 mmol, 94%) of compound 6g was obtained after 12 h as an
off-white powder. H NMR (399.8 MHz, C6D6, 25 °C): δ 13.43
Hz, 2H, 10- and 12-H), 7.25 (m, 4H, 29-, 30-, 36-, and 37-H),
3
3
4
7.13 (t, JHH ) 7.8 Hz, 1H, 11-H), 7.05 (dd, JHH ) 7.6 and JHH
) 2.0 Hz, 1H, 4-H), 6.60 (dd, 3JHH ) 7.6 and 4JHH ) 2.0 Hz, 1H,
6-H), 6.53 (vt, JHH ) 7.6 Hz, 1H, 5-H), 3.26 (s, 6H, 2 × OCH3),
2.13 (s, 12H, 4 × CH3). 13C{1H} NMR (100.5 MHz, C6D6, 25
°C): δ 168.3 (CH, C7), 160.1 (Cq, C2), 156.6 (Cq, C17 and C23),
145.8 (Cq, C8), 136.3 (CH, C4), 135.2 and 135.1 (Cq each, C9,
C13, C14, and C20), 133.5 (Cq, C26), 132.2 (CH, C6), 132.0 and
131.1 (Cq each, C27, C32, C34, and C39), 130.8 (CH, C15, C19,
C21, and C25), 130.7 (Cq, C16, C18, C22, and C24), 129.9 (CH,
C10 and C12), 128.8 and 127.1 (CH each, C28, C31, C35, and
C35), 127.2 (CH, C33), 127.1 (Cq, C3), 126.0 (CH, C11), 125.5
and 125.2 (CH each, C29, C30, C36, and C37), 119.2 (Cq, C1),
118.5 (CH, C5), 59.1 (CH3, 2 × OCH3), 16.1 (CH3, 16-, 18-, 22-,
and 24-CH3). Anal. Calcd for C45H39NO3 (641.80 g mol-1): C,
84.21; H, 6.12; N, 2.18. Found: C, 84.20; H, 6.30; N, 2.10.
1
(s, 1H, OH), 8.22 (s, 1H, 33-H), 7.87 (s, 1H, 7-H), 7.82 and 7.68
3
(m each, 2H each, 28-, 30-, 35-, and 38-H), 7.45 (d, JHH ) 7.9
Hz, 2H, 10- and 12-H), 7.24 (m, 4H, 29-, 30-, 36-, and 37-H),
3
3
7.20 (t, JHH ) 7.9 Hz, 1H, 11-H), 7.03 (d, JHH ) 7.4 Hz, 1H,
4-H), 6.69 (s, 4H, 15-, 19-, 21-, and 25-H), 6.59 (m, 1H, 6-H),
6.54 (m, 1H, 5-H), 3.80 (s, 6H, 17- and 23-OCH3), 3.37 (s, 12H,
16-, 18-, 22-, and 24-OCH3). 13C{1H} NMR (100.5 MHz, C6D6,
25 °C): δ 168.3 (CH, C7), 159.9 (Cq, C2), 154.1 (Cq, C16, C18,
C22, and C24), 145.9 (Cq, C8), 138.8 (Cq, C17 and C23), 136.6
(CH, C4), 135.4 (Cq, C9 and C13), 134.8 (Cq, C14 and C20), 132.9
and 127.2 (Cq each, C26 and C3), 132.3 (CH, C6), 132.0 and
131.0 (Cq each, C27, C32, C34, and C39), 130.3 (CH, C10 and
C12), 128.8 and 126.9 (CH each, C28, C31, C35, and C38), 127.3
(CH, C33), 126.2 (CH, C11), 125.8 and 125.3 (CH each, C29, C30,
C36, and C37), 119.2 (Cq, C1), 119.0 (CH, C5), 108.0 (CH, C15,
C19, C21, and C25), 60.5 (CH3, 17- and 23-OCH3), 56.0 (CH3,
16-, 18-, 22-, and 24-OCH3). Anal. Calcd for C45H39NO7 (705.79
g mol-1): C, 76.58; H, 5.57; N, 1.98. Found: C, 77.00; H, 5.11;
N, 1.67.
General Procedure for the Synthesis of (K2-N,O)-Salicylaldi-
minato Nickel Methyl Pyridine Complexes (7a-f-pyr and 8a-
g-pyr). Method A. To [(tmeda)NiMe2] (20.4 mg, 100 µmol) and
the respective salicylaldimine 5a-f, 6a-f (100 µmol) in a 10 mL
septum capped Schlenk tube was added a solution of pyridine (120
mg, 1.52 mmol) in 5 mL of benzene at 25 °C. Immediate methane
evolution was observed, which ceased within 5-10 min. The
Salicylaldimine 6f. The preparation of compound 6f failed
following the general procedure due to incomplete conversion

2358 Organometallics, Vol. 26, No. 9, 2007
Go¨ttker-Schnetmann et al.
resulting orange to red solution was stirred for an additional 30
min at 25 °C, and all volatiles were then removed by sublimation
at -10 °C (crushed ice/sodium chloride) under high vacuum (10-3
mbar). Alternatively, the reaction was conducted in 8 mL of diethyl
ether containing pyridine (120 mg, 1.52 mmol) where salicylaldi-
mines did not completely dissolve, methane evolution was much
slower, and the reaction time was prolonged to 3 h at 25 °C, after
which time all volatiles were removed in vacuo (10-3 mbar).
Independent of the solvent used, the resulting solid was transferred
to a Schlenk frit, washed with 4 × 2 mL of pentane, and dried
under high vacuum (10-3 mbar) to yield an analytically pure sample
of pyridine complexes 7a-f-pyr and 8a-g-pyr. Method B. To
[(pyridine)2NiMe2] (26.0 mg, 105 µmol) and the respective salicyl-
aldimine 5a-f, 6a-f (100 µmol) in a 10 mL septum capped
Schlenk tube was added benzene (5 mL) at 25 °C. Immediate
methane evolution was observed, which ceased within 5-10 min.
The resulting orange to red solution was stirred for an additional
120 min at 25 °C, during which time excess [(pyridine)2NiMe2]
decomposed to nickel black. The resulting mixture was filtrated to
remove nickel black, the residue was extracted with benzene (4 ×
0.5 mL), and all volatiles were removed by sublimation at -10 °C
(crushed ice/sodium chloride) under high vacuum (10-3 mbar) to
yield analytically pure samples of pyridine complexes 7a-f-pyr
and 8a-g-pyr.
C13, C14, and C20), 135.8 (CH, p-C pyridine), 129.8 (CH, C10
and C12), 126.5 (CH, C11), 125.6 (CH, C15, C19, C21, and C25),
122.7 (CH, m-C pyridine), 121.4 (Cq, C1), 121.2 (CH, C17 and
C23), 96.8 (Cq, C5), 71.4 (Cq, C3), 35.2 (Cq, 4 × tBu), 31.7 (CH3,
t
4 × Bu), -7.6 (CH3, Ni-CH3). Anal. Calcd for C47H56N2OI2Ni
(977.46 g mol-1): C, 57.75; H, 5.77; N, 2.87. Found: C, 58.00;
H, 5.95; N, 3.06.
Complex 7c-pyr. Following the general procedure of method
A, 90.1 mg (89.3 µmol, 89.3%) of compound 7c-pyr was obtained
from [(tmeda)NiMe2] (20.4 mg, 100 µmol), salicylaldimine 5c (85.8
mg, 100 µmol), and pyridine (120 mg, 1.52 mmol) in benzene
solution as a red powder. Method B gave 92.2 mg (91.3 µmol,
91.3%) of compound 7c-pyr from [(pyridine)2NiMe2] (26.0 mg,
1
105 µmol) and salicylaldimine 5c (85.8 mg, 100 µmol). H NMR
(399.8 MHz, C6D6, 25 °C): δ 8.34 (m, 2H, o-H pyridine), 7.99 (d,
4JHH ) 2.1 Hz, 1H, 4-H), 7.68 (s, 4H, 15-, 19-, 21-, and 25-H),
7.50 (d, 3JHH ) 7.8 Hz, 2H, 10- and 12-H), 7.13 (t, 3JHH ) 7.8 Hz,
1H, 11-H), 6.78 (s, 1H, 7-H), 6.70 (m, 1H, p-H pyridine), 6.63 (d,
4JHH ) 2.1 Hz, 1H, 6-H), 6.49 (m, 2H, m-H pyridine), 5.07 (s,
t
2H, 2 × OH), 1.48 (s, 36H, 4 × Bu), -0.62 (s, 3H, Ni-CH3).
13C{1H} NMR (100.5 MHz, C6D6, 25 °C): δ 168.3 (CH, C7), 163.4
(Cq, C2), 153.5 (Cq, C17 and C23), 151.8 (CH, o-C pyridine), 150.0
(Cq, C8), 148.7 (CH, C4), 141.9 (CH, C6), 137.0 (Cq, C9 and C13),
136.1 (Cq, C16, C18, C22, and C24), 135.9 (CH, p-C pyridine),
131.4 (Cq, C14 and C20), 129.2 (CH, C10 and C12), 128.3 (CH,
C15, C19, C21, and C25), 126.7 (CH, C11), 122.9 (CH, m-C
pyridine), 122.0 (Cq, C1), 96.7 (Cq, C5), 71.4 (Cq, C3), 34.7 (Cq, 4
× Bu), 30.5 (CH3, 4 × Bu), -8.0 (CH3, Ni-CH3). Anal. Calcd
for C47H56N2O3I2Ni (1008.46): C, 55.98; H, 5.50; N, 2.78. Found:
C, 56.41; H, 5.89; N, 2.45.
Complex 7b-pyr. Following the general procedure of method
A, 90.9 mg (93.0 µmol, 93.0%) of compound 7b-pyr was obtained
from [(tmeda)NiMe2] (20.4 mg, 100 µmol), salicylaldimine 5b (82.6
mg, 100 µmol), and pyridine (120 mg, 1.52 mmol) in diethyl ether
as a red powder. Method B gave 89.8 mg (91.9 µmol, 91.9%) of
compound 7b-pyr from [(pyridine)2NiMe2] (26.0 mg, 105 µmol)
and salicylaldimine 5b (82.6 mg, 100 µmol). Crystals suitable for
X-ray analysis were obtained within 4 d at 25 °C after layering a
solution of complex 7b-pyr (26 mg) in 0.4 mL of benzene with 3
mL of pentane.
t
t
Crystallographic Data for 7b-pyr‚1.5C6H6. C56H65N2OI2Ni, Mr
) 1093.63, monoclinic, space group P21/c (no. 14), a ) 17.81(7),
b ) 18.24(7), c ) 19.05(7) Å, R ) 90.00(7)°, â ) 114.45(7)°, γ
) 90.00(7), V ) 5643(38) Å3, Z ) 4, Fcalcd ) 1.280, µ ) 14.76
cm-1, no. of rflns measd ) 32 147, no. of unique rflns ) 9923,
no. of rflns I > 2σ(I) ) 5173, R1(I > 2σ(I)) ) 0.0548, R1 (all
data) ) 0.1066, wR2 ) 0.1450, T ) 293(2) K, GOF ) 0.889. The
intensity data were collected on a Bruker AXS CCD diffractometer
with graphite-monochromated Mo KR radiation (0.71070 Å). The
structure was solved by direct methods with SHELLXS-97 and
refined by full matrix least-squares on F2 using SHELXL-97.
Hydrogen atoms were treated in a riding model. One tert-butyl
group is disordered and was refined isotropically over two split
Complex 7e-pyr. Following the general procedure of method
A, 74.2 mg (85.4 µmol, 85.4%) of compound 7e-pyr was obtained
from [(tmeda)NiMe2] (20.4 mg, 100 µmol), salicylaldimine 5e (71.8
mg, 100 µmol), and pyridine (120 mg, 1.52 mmol) in benzene
solution as a red powder. Method B gave 78.9 mg (90.8 µmol,
90.8%) of compound 7e-pyr from [(pyridine)2NiMe2] (26.0 mg,
1
105 µmol) and salicylaldimine 5e (85.8 mg, 100 µmol). H NMR
1
positions. 7b-pyr. H NMR (399.8 MHz, C6D6, 25 °C): δ 8.29
(399.8 MHz, C6D6, 25 °C): δ 8.18 (m, 2H, o-H pyridine), 7.97 (d,
4
3
(m, 2H, o-H pyridine), 7.95 (d, JHH ) 1.9 Hz, 1H, 4-H), 7.70 (s,
4JHH ) 2.0 Hz, 1H, 4-H), 7.43 (d, JHH ) 7.8 Hz, 2H, 10- and
4H, 15-, 19-, 21-, and 25-H), 7.60 (s, 2H, 17- and 23-H), 7.49 (d,
12-H), 7.39 (s, 4H, 15-, 19-, 21-, and 25-H), 7.15 (1H occluded by
C6D5H, 11-H), 7.13 (s, 1H, 7-H), 6.88 (d, 4JHH ) 2.0 Hz, 1H, 6-H),
6.62 (m, 1H, p-H pyridine), 6.31 (m, 2H, m-H pyridine), 3.38 (s,
6H, 17- and 23-OCH3), 2.28 (s, 12H, 16-, 18-, 22-, and 24-CH3),
-0.60 (s, 3H, Ni-CH3). 13C{1H} NMR (100.5 MHz, C6D6, 25
°C): δ 167.6 (CH, C7), 163.4 (Cq, C2), 157.1 (Cq, C17 and C23),
151.8 (CH, o-C pyridine), 149.9 (Cq, C8), 148.9 (CH, C4), 141.9
(CH, C6), 136.0 and 135.7 (Cq each, C9, C13, C14, and C20), 135.8
3
3JHH ) 7.8 Hz, 2H, 10- and 12-H), 7.18 (d, JHH ) 7.8 Hz, 1H,
4
11-H), 6.89 (s, 1H, 7-H), 6.69 (d, JHH ) 1.9 Hz, 1H, 6-H), 6.67
(m, 1H, p-H pyridine), 6.40 (m, 2H, m-H pyridine), 1.40 (s, 36H,
t
4 × Bu), -0.55 (s, 3H, Ni-CH3). 13C{1H} NMR (100.5 MHz,
C6D6, 25 °C): δ 168.2 (CH, C7), 163.3 (Cq, C2), 151.8 (CH, o-C
pyridine), 151.0 (Cq, C16, C18, C22, and C24), 150.5 (Cq, C8),
148.7 (CH, C4), 142.0 (CH, C6), 139.6 and 137.2 (Cq each, C9,

Nickel(II)-Methyl Pyridine Polymerization Catalysts
Organometallics, Vol. 26, No. 9, 2007 2359
(CH, p-C pyridine), 131.5 (CH, C15, C19, C21, and C25), 130.9
(Cq, C16, C18, C22, and C24), 129.9 (CH, C10 and C12), 126.3
(CH, C11), 122.7 (CH, m-C pyridine), 121.3 (Cq, C1), 97.3 (Cq,
C5), 71.7 (Cq, C3), 59.4 (CH3, 17- and 23-OCH3), 16.4 (CH3, 16-,
18-, 22-, and 24-CH3), -7.9 (CH3, Ni-CH3). Anal. Calcd for
C37H36N2O3I2Ni (869.19 g mol-1): C, 51.13; H, 4.17; N, 3.22.
Found: C, 51.54; H, 4.29; N, 3.29.
7-H), 7.29 and 7.25 (m each, 2H each, 29-, 30-, 36-, and 37-H),
3
3
4
7.20 (t, JHH ) 7.8 Hz, 1H, 11-H), 7.19 (dd, JHH ) 7.9 and JHH
) 1.9 Hz, 1H, 4-H), 6.67 (dd, 3JHH ) 7.9 and 4JHH ) 1.9 Hz, 1H,
6-H), 6.39 (vt, 3JHH ) 7.9 Hz, 1H, 5-H), 6.23 (m, 1H, p-H pyridine),
t
5.71 (m, 2H, m-H pyridine), 1.40 (s, 36H, 4 × Bu), -0.71 (s, 3H,
Ni-CH3). 13C{1H} NMR (100.5 MHz, C6D6, 25 °C): δ 169.2 (CH,
C7), 165.5 (Cq, C2), 151.0 (Cq, C8), 151.0 (CH, o-C pyridine),
150.8 (Cq, C16, C18, C22, and C24), 140.0 and 137.5 (Cq
each, C9, C13, C14, and C20), 137.6 (Cq, C26), 136.6 (CH, C4),
134.7 (CH, p-C pyridine), 133.6 (CH, C6), 132.0 and 131.2 (Cq
each, C27, C32, C34, and C39), 130.4 (Cq, C3), 130.0 (CH, C10
and C12), 128.9 and 128.2 (CH each, C28, C31, C35, and
C38), 126.3 (CH, C11), 125.6 (CH, C15, C19, C21, and C25), 125.3
(CH, C33), 125.0 and 124.6 (CH each, C29, C30, C36, and C37),
121.7 (CH, m-C pyridine), 121.3 (Cq, C1), 121.0 (CH, C17 and
t
t
C23), 112.9 (CH, C5), 35.2 (Cq, 4 × Bu), 31.8 (CH3, 4 × Bu),
-8.7 (CH3, Ni-CH3). Anal. Calcd for C61H67N2ONi (902.91 g
mol-1): C, 81.15; H, 7.48; N, 3.10. Found: C, 80.88; H, 7.10; N,
3.00.
Complex 8a-pyr. Following the general procedure of method
A, 82.7 mg (87.1 µmol, 87.1%) of compound 8a-pyr was obtained
from [(tmeda)NiMe2] (20.4 mg, 100 µmol), salicylaldimine 6a (79.8
mg, 100 µmol), and (pyridine 120 mg, 1.52 mmol) in diethyl ether
as an orange-red powder. Method B gave 88.0 mg (92.3 µmol,
92.3%) of compound 8a-pyr from [(pyridine)2NiMe2] (26.0 mg,
1
105 µmol) and salicylaldimine 6a (79.8 mg, 100 µmol). H NMR
(399.8 MHz, C6D6, 25 °C): δ 8.27 (s, 4H, 15-, 19-, 21-, and 25-
H), 8.07 (s, 1H, 33-H), 7.89 and 7.73 (m each, 2H each, 28-, 31-,
35-, and 38-H), 7.71 (s, 2H, 17- and 23-H), 7.33 (m br, 2H, o-H
pyridine), 7.31 and 7.18 (m each, 2H each, 29-, 30-, 36-, and
37-H), 7.12 (dd, 3JHH ) 7.8 and 4JHH ) 1.8 Hz, 1H, 4-H), 6.92 (m,
3
4
4H, 10-12-H and 7-H), 6.67 (dd, JHH ) 7.8 and JHH ) 1.8 Hz,
1H, 6-H), 6.38 (vt, JHH ) 7.8 Hz, 1H, 5-H), 6.14 (m, 1H, p-H
pyridine), 5.54 (m, 2H, m-H pyridine), -1.08 (s, 3H, Ni-CH3).
13C{1H} NMR (100.5 MHz, C6D6, 25 °C): δ 168.1 (CH, C7), 166.2
(Cq, C2), 150.9 (Cq,C8), 150.3 (CH, o-C pyridine), 141.8 (Cq, C9
and C13), 137.8 (CH, C4), 136.4 (Cq, C26), 135.2 (CH, p-C
pyridine), 133.4 (Cq, C10 and C14), 133.3 (CH, C6), 131.9 and
130.0 (Cq each, C27, C32, C34, and C39), 131.8 (Cq, q, 2JCF ) 33
Hz, C16, C18, C22, and C24), 131.2 (Cq, C3), 130.9 (CH, C15,
C19, C21, and C25), 130.7 (CH, C10 and C12), 128.1 and
128.0 (CH each, C28, C31, C35, and C38), 126.6 (CH, C11), 125.5
(CH, C33), 125.2 and 124.9 (CH each, C29, C30, C36, and C37),
124.1 (Cq, q, 1JCF ) 272 Hz, 4 × CF3), 122.1 (CH, m-C pyridine),
121.1 (CH, m, C17 and C23), 119.2 (Cq, C1), 114.1 (CH, C5),
-8.3 (CH3, Ni-CH3). Anal. Calcd for C49H30N2OF12Ni (949.56 g
mol-1): C, 61.99; H, 3.18; N, 2.95. Found: C, 61.36; H, 3.40; N,
3.21.
Complex 8c-pyr. Following the general procedure of method
A, 85.3 mg (91.2 µmol, 91.2%) of compound 8c-pyr was obtained
from [(tmeda)NiMe2] (20.4 mg, 100 µmol), salicylaldimine 6c (78.2
mg, 100 µmol), and pyridine (120 mg, 1.52 mmol) in diethyl ether
as an orange-red powder. Method B gave 84.8 mg (90.7 µmol,
90.7%) of compound 8c-pyr from [(pyridine)2NiMe2] (26.0 mg,
1
105 µmol) and salicylaldimine 6c (78.2 mg, 100 µmol). H NMR
(399.8 MHz, C6D6, 25 °C): δ 8.14 (s, 1H, 33-H), 8.13 and 7.82
(m each, 2H each, 29-, 30-, 36-, and 36-H), 7.83 (s, 4H, 15-, 19-,
3
21-, and 25-H), 7.55 (d, JHH ) 7.8 Hz, 2H, 10- and 12-H), 7.36
(m, 2H, o-H pyridine), 7.33 and 7.28 (m each, 2H each, 28-, 31-,
35-, and 38-H), 7.25 (s, 1H, 7-H), 7.20 (t, 3JHH ) 7.8 Hz, 1H, 11-
3
4
H), 7.18 (dd, JHH ) 8.0 Hz and JHH ) 2.0 Hz, 1H, 4-H), 6.62
3
4
(dd, JHH ) 8.0 Hz and JHH ) 2.0 Hz, 1H, 6-H), 6.40 (vt, JHH
8.0 Hz, 1H, 5-H), 6.27 (m, 1H, p-H pyridine), 5.82 (m, 2H, m-H
)
t
pyridine), 4.99 (s, 2H, 2 × OH), 1.46 (s, 36H, 4 × Bu), -0.78 (s,
3H, Ni-CH3). 13C{1H} NMR (100.5 MHz, C6D6, 25 °C): δ 169.3
(CH, C7), 165.5 (Cq, C2), 153.2 (Cq, C17 and C23), 151.0 (CH,
o-C pyridine), 150.5 (Cq, C8), 137.8 (Cq, C26), 137.1 (Cq, C9 and
C13), 136.3 (CH, C4), 135.9 (Cq, C16, C18, C22, and C24), 134.7
(CH, p-C pyridine), 133.5 (CH, C6), 132.0, 131.9, and 131.2 (Cq
each, C14, C20, C27, C39, C32, and C34), 130.4 (Cq, C3), 129.3
(CH, C10 and C12), 129.0, 128.4, and 128.3 (CH each, C15, C19,
C21, C25, C28, C31, C35, and C38), 126.5 (CH, C11), 125.3 (CH,
C33), 125.0 and 124.7 (CH each, C29, C30, C36, and C37), 122.8
(Cq, C1), 121.9 (CH, m-C pyridine), 112.9 (CH, C5), 34.8 (Cq, 4
t
× tBu), 30.5(CH3, 4 × Bu), -9.1 (CH3, Ni-CH3). Anal. Calcd
for C61H66N2O3Ni (934.90 g mol-1): C, 78.37; H, 7.22; N, 3.00.
Found: C, 78.00; H, 7.53; N, 2.84.
Complex 8b-pyr. Following the general procedure of method
A, 78.4 mg (86.8 µmol, 86.8%) of compound 8b-pyr was obtained
from [(tmeda)NiMe2] (20.4 mg, 100 µmol), salicylaldimine 6b
(75.1 mg, 100 µmol), and pyridine (120 mg, 1.52 mmol) in benzene
as an orange-red powder. Method B gave 82.1 mg (90.9 µmol,
90.9%) of compound 8b-pyr from [(pyridine)2NiMe2] (26.0 mg,
105 µmol) and salicylaldimine 5b (75.1 mg, 100 µmol). 1H NMR
(399.8 MHz, C6D6, 25 °C): δ 8.12 (s, 1H, 33-H), 8.07 and 7.79
(m each, 2H each, 28-, 31-, 35-, and 38-H), 7.85 (s, 4H, 15-, 19-,
3
21-, and 25-H), 7.55 (s, 2H, 17- and 23-H), 7.54 (d, JHH ) 7.8
Hz, 2H, 10- and 12-H), 7.35 (m, 2H, o-H pyridine), 7.34 (s, 1H,

2360 Organometallics, Vol. 26, No. 9, 2007
Go¨ttker-Schnetmann et al.
Complex 8d-pyr. Following the general procedure of method
A, 65.4 mg (89.2 µmol, 89.2%) of compound 8d-pyr was obtained
from [(tmeda)NiMe2] (20.4 mg, 100 µmol), salicylaldimine 6d (58.2
mg, 100 µmol), and pyridine (120 mg, 1.52 mmol) in benzene
solution as an orange-red powder. 1H NMR (399.8 MHz, C6D6, 25
°C): δ 8.11 (s, 1H, 33-H), 7.93 and 7.77 (m each, 2H each, 28-,
31-, 35-, and 38-H), 7.71 (s, 1H, 7-H), 7.53 (s, 4H, 15-, 19-, 21-,
3
and 25-H), 7.43 (d, JHH ) 7.6 Hz, 2H, 10- and 12-H), 7.37 (s,
2H, o-H pyridine), 7.14 (m, 6H, 4-, 11-, 29-, 30-, 36-, and 37-H),
6.94 (dd, 3JHH ) 7.6 and 4JHH ) 1.8 Hz, 1H, 6-H), 6.85 (s, 2H, 17-
and 23-H), 6.48 (t, JHH ) 7.6 Hz, 1H, 5-H), 6.19 (m, 1H, p-H
pyridine), 5.58 (m, 2H, m-H pyridine), 2.22 (s, 12H, 4 × CH3),
-0.72 (s, 3H, Ni-CH3). 13C{1H} NMR (100.5 MHz, C6D6, 25
°C): δ 168.5 (CH, C7), 165.7 (Cq, C2), 151.0 (CH, o-C pyridine),
150.7 (Cq, C8), 140.6 and 137.5 (Cq each, C9, C13, 14 and C20),
137.6 (Cq, C16, C18, C22, and C24), 136.7 (Cq, C26), 136.7 (CH,
C4), 134.6 (CH, p-C pyridine), 133.9 (CH, C6), 132.0 and 131.2
(Cq each, C27, C32, C34, and C39), 130.6 (Cq, C3), 130.1 (CH,
C10 and C12), 129.0 (CH, C15, C19, C21, and C25), 128.9 (CH,
C17 and C23), 128.5 and 128.2 (CH each, C28, C31, C35, and
C38), 125.9 (CH, C11), 125.4 (CH, C33), 125.0 and 124.7 (CH
each, C29, C30, C36, and C37), 121.7 (CH, m-C pyridine), 120.7
(Cq, C1), 113.1 (CH, C5), 21.5 (CH3, 16-, 18-, 22-, and 24-CH3),
-8.3 (CH3, Ni-CH3). Anal. Calcd for C49H42N2ONi (733.58 g
mol-1): C, 80.23; H, 5.77; N, 3.82. Found: C, 80.00; H, 5.86; N,
3.43.
Complex 8f-pyr. Following the general procedure of method
A, 70.7 mg (88.6 µmol, 88.6%) of compound 8f-pyr was obtained
from [(tmeda)NiMe2] (20.4 mg, 100 µmol), salicylaldimine 6f (64.6
mg, 100 µmol), and pyridine (120 mg, 1.52 mmol) in a diethyl
ether suspension as an orange-red powder. Method B gave 72 mg
(92.1 µmol, 92.1%) of compound 8f-pyr from [(pyridine)2NiMe2]
(26.0 mg, 105 µmol) and salicylaldimine 6f (70.6 mg, 100 µmol).
Crystals suitable for X-ray analysis were obtained within 3 d at 25
°C after layering a solution of complex 8f-pyr (20 mg) in 0.4 mL
of benzene with 1 mL of pentane/diethyl ether (3:1).
Crystallographic Data for 8f-pyr‚1.5C6H6. C58H51N2O5Ni, Mr
) 914.72, triclinic, space group P-1 (no. 2), a ) 10.116(3), b )
15.276(4), c ) 16.317(5) Å, R ) 85.398(5), â ) 80.664(5), γ )
81.100(6)°, V ) 2454.2(12) Å3, Z ) 2, Fcalcd ) 1.238, µ ) 4.46
cm-1, no. of rflns measd ) 17 777, no. of unique rflns ) 11 188,
no. of rflns I > 2σ(I) ) 4353, R1(I > 2σ(I)) ) 0.0406, R1, all
data ) 0.1403, wR2 ) 0.0850, T ) 293(2) K, GOF ) 0.682. The
intensity data were collected on a Bruker AXS CCD diffractometer
with graphite-monochromated Mo KR anode radiation (0.71070 Å).
The structure was solved by direct methods with SHELLXS-97.
1
Hydrogen atoms were treated in a riding model. 8f-pyr. H NMR
(399.8 MHz, C6D6, 25 °C): δ 8.11 (s, 1H, 33-H), 7.88 and 7.76
(m each, 2H each, 29-, 30-, 36-, and 37-H), 7.58 (s, 1H, 7-H), 7.44
(d, 3JHH ) 8.0 Hz, 2H, 10- and 12-H), 7.40 (m, 2H, o-H pyridine),
7.23 (d, 4JHH ) 2.0 Hz, 4H, 15-, 19-, 21-, and 25-H), 7.16 (m, 5H,
3
4-, 28-, 31-, 35-, and 38-H), 7.09 (t, JHH ) 8.0 Hz, 1H, 11-H),
6.82 (dd, 3JHH ) 8.0 Hz and 4JHH ) 2.0 Hz, 1H, 6-H), 6.68 (t, dd,
3JHH ) 2.0 Hz, 2H, 17- and 23-H), 6.40 (vt, JHH ) 8.0 Hz, 1H,
5-H), 6.18 (m, 1H, p-H pyridine), 5.56 (m, 2H, m-H pyridine), 3.55
(s, 12H, 4 × OCH3), -0.72 (s, 3H, Ni-CH3). 13C{1H} NMR (100.5
MHz, C6D6, 25 °C): δ 168.3 (CH, C7), 165.6 (Cq, C2), 161.3 (Cq,
C16, C18, C22, and C24), 150.8 (CH, C8 and o-C pyridine), 142.4
and 136.3 (Cq each, C9, C13, C14, and C20), 137.1 (Cq, C26),
136.9 (CH, C4), 134.7 (CH, p-C pyridine), 133.9 (CH, C6), 132.0
and 131.0 (Cq each, C27, C32, C34, and C39), 130.6 (Cq, C3),
130.1 (CH, C10 and C12), 128.2 and 127.9 (CH each, C28, C31,
C35, and C38), 126.3 (CH, C11), 125.4 (Cq, C33), 125.1 and 124.8
(CH each, C29, C30, C36, and C37), 121.9 (CH, m-C pyridine),
120.7 (Cq, C1), 113.3 (CH, C5), 109.1 (CH, C15, C19, C21, and
C25), 100.8 (CH, C17 and C23), 55.3 (CH3, 4 × OCH3), -8.2
(CH3, Ni-CH3). Anal. Calcd for C49H42N2O5Ni (797.57 g mol-1):
C, 73.79; H, 5.31; N, 3.51. Found: C, 74.00; H, 5.40; N, 3.40.
Complex 8e-pyr. Following the general procedure of method
A, 66.2 mg (83.4 µmol, 83.4%) of compound 8e-pyr was obtained
from [(tmeda)NiMe2] (20.4 mg, 100 µmol), salicylaldimine 6e (64.2
mg, 100 µmol), and pyridine (120 mg, 1.52 mmol) in a diethyl
ether suspension as an orange powder. Method B gave 75.2 mg
(95.7 µmol, 95.7%) of compound 8e-pyr from [(pyridine)2NiMe2]
(26.0 mg, 105 µmol) and salicylaldimine 6e (64.2 mg, 100 µmol).
1H NMR (399.8 MHz, C6D6, 25 °C): δ 8.10 (s, 1H, 33-H), 7.89
and 7.75 (m each, 2H each, 28-, 31-, 35-, and 38-H), 7.71 (s, 1H,
3
7-H), 7.56 (s, 4H, 15-, 19-, 21-, and 25-H), 7.42 (d, JHH ) 7.6
Hz, 2H, 10- and 12-H), 7.37 (m, 2H, o-H pyridine), 7.21 (dd, 3JHH
4
) 7.6 and JHH ) 2.0 Hz, 1H, 4-H), 7.19 and 7.10 (m each, 2H
each, 29-, 30-, 36-, and 37-H), 7.17 (t, 3JHH ) 7.6 Hz, 1H, 11-H),
6.95 (dd, 3JHH ) 7.6 and 4JHH ) 2.0 Hz, 1H, 6-H), 6.50 (vt, JHH
)
7.6 Hz, 1H, 5-H), 6.21 (m, 1H, p-H pyridine), 5.60 (m, 2H, m-H
pyridine), 3.29 (s, 6H, 17- and 23-OCH3), 2.27 (s, 12H, 16-, 18-,
22-, and 24-CH3), -0.73 (s, 3H, Ni-CH3). 13C{1H} NMR (100.5
MHz, C6D6, 25 °C): δ 168.4 (CH, C7), 165.7 (Cq, C2), 156.8
(Cq, C17 and C23), 150.9 (CH, o-C pyridine), 150.7 (Cq, C8), 137.4
(Cq, C26), 136.7 (CH, C4), 136.4 and 136.1 (Cq each, C9,
C13, C14, and C20), 134.6 (CH, p-C pyridine), 133.8 (CH, C6),
131.9 and 131.1 (Cq each, C27, C32, C34, and C39), 131.6 (CH,
C15, C19, C21, and C25), 130.7 (Cq, C3), 130.6 (Cq, C16, C18,
C22, and C24), 130.0 (CH, C10 and C12), 128.4 and 128.2
(CH each, C28, C31, C35, and C38), 125.9 (CH, C11), 125.4
(CH, C33), 125.0 and 124.7 (CH each, C29, C30, C36, and C37),
121.7 (CH, m-C pyridine), 120.7 (Cq, C1), 113.1 (CH, C5), 59.2
(CH3, 17- and 23-OCH3), 16.4 (CH3, 16-, 18-, 22-, and 24-CH3),
-8.6 (CH3, Ni-CH3). Anal. Calcd for C51H46N2O3Ni (793.63 g
mol-1): C, 77.18; H, 5.84; N, 3.53. Found: C, 76.43; H, 6.12; N,
3.01.
Complex 8g-pyr. Following the general procedure method A,
77.4 mg (90.3 µmol, 90.3%) of compound 8g-pyr was obtained
from [(tmeda)NiMe2] (20.4 mg, 100 µmol), salicylaldimine 6g (70.6
mg, 100 µmol), and pyridine (120 mg, 1.52 mmol) in diethyl ether
as an orange-red powder. Method B gave 72 mg (92.1 µmol, 92.1%)
of compound 8g-pyr from [(pyridine)2NiMe2] (26.0 mg, 105 µmol)
and salicylaldimine 6g (70.6 mg, 100 µmol). 1H NMR (399.8 MHz,

Nickel(II)-Methyl Pyridine Polymerization Catalysts
Organometallics, Vol. 26, No. 9, 2007 2361
C6D6, 25 °C): δ 8.11 (s, 1H, 33-H), 7.83 and 7.75 (m each, 2H
salicylaldimines, condensation of terphenylamine 4a (518 mg, 1
3
each, 29-, 30-, 36-, and 37-H), 7.54 (s, 1H, 7-H), 7.52 (d, JHH
)
mmol) with 5-nitrosalicylaldehyde (167 mg, 1 mmol) in 15 mL of
1
8.0 Hz, 2H, 10- and 12-H), 7.35 (m, 2H, o-H pyridine), 7.25 (s,
methanol gave salicylaldimine 12 (500 mg, 0.75 mmol, 75%). H
3
4H, 15-, 19-, 21-, and 25-H), 7.23 (t, JHH ) 8.0 Hz, 1H, 11-H),
NMR (399.8 MHz, CDCl3, 25 °C): δ 12.79 (s, 1H, OH), 8.12 (dd,
7.16 (m, 5H, 4-, 28-, 31-, 35-, and 38-H), 6.77 (dd, 3JHH ) 8.0 Hz
3JHH ) 9.2 Hz, JHH ) 2.8 Hz, 1H, 4-H), 8.06 (s, 1H, 7-H), 7.89
4
4
4
and JHH ) 2.0 Hz, 1H, 6-H), 6.39 (vt, JHH ) 8.0 Hz, 1H, 5-H),
(d, JHH ) 2.8 1H, 6-H), 7.87 (s, 4H, 15-, 19-, 21-, and 25-H),
6.16 (m, 1H, p-H pyridine), 5.59 (m, 2H, m-H pyridine), 3.86 (s,
6H, 17- and 23-OCH3), 3.70 (s, 12H, 16-, 18-, 22-, and 24-OCH3),
-0.76 (s, 3H, Ni-CH3). 13C{1H} NMR (100.5 MHz, C6D6, 25
°C): δ168.3 (CH, C7), 165.5 (Cq, C2), 154.0 (Cq, C16, C18, C22,
and C24), 150.8 (Cq, C17 and C23), 150.5 (CH, o-C pyridine),
139.0 and 136.4 (Cq each, C9, C13, C14, C20), 136.9 (CH, C4),
136.8 (Cq, C26), 134.9 (CH, p-C pyridine), 133.7 (CH, C6), 131.9
and 131.0 (Cq each, C27, C32, C34, and C39), 130.7 (Cq, C3),
129.8 (CH, C10 and C12), 128.7 and 128.5 (CH each, C28, C31,
C35, and C38), 126.3 (CH, C11), 125.5 (Cq, C33), 125.2 and 124.9
(CH each, C29, C30, C36, C37), 122.1 (CH, m-C pyridine), 120.7
(Cq, C1), 113.4 (CH, C5), 109.4 (CH, C15, C19, C21, and C25),
60.7 (CH3, 17- and 23-OCH3), 56.4 (CH3, 16-, 18-, 22-, and 24-
OCH3), -8.7 (CH3, Ni-CH3), C8 not detected. Anal. Calcd for
C45H38N2O7Ni (857.62 g mol-1): C, 71.43; H, 5.41; N, 3.27.
Found: C, 71.00; H, 5.72; N, 2.84.
1.83 (s, 2H, 17- and 23-H), 7.58 (m, 3H, 10-12-H), 7.02 (d, 3JHH
) 9.2 Hz, 1H, 5-H). 13C{1H} NMR (100.5 MHz, CDCl3, 25 °C):
δ 168.4 (CH, C7), 166.0 (Cq, C2), 144.5 (Cq, C8), 140.4 and 132.1
2
(Cq each, C9, C13, C14, and C20), 140.1 (Cq, C5), 132.1 (q, JCF
) 34 Hz, C16, C18, C22, and C24), 131.5 (CH, C10 and C12),
129.8 (CH, C15, C19, C21, and C25), 129.3 (CH, C4), 128.3 (CH,
1
C6), 127.5 (CH, C11), 123.0 (q, JCF ) 272 Hz, 4 × CF3), 121.4
(m, CH, C17 and C23), 118.4 (CH, C3), 116.7 (Cq, C1). (b)
Preparation of Complex 10a-pyr. To a mixture of [(tmeda)Ni-
(CH3)2] (100 mg, 0.49 mmol) and salicalyldimine 12 (326 mg, 0.49
mmol) in a 25 mL Schlenk flask was added a solution of 0.5 mL
of pyridine in diethyl ether (10 mL) at -30 °C under stirring. The
temperature was slowly raised to 0 °C, while the color changed to
orange-red. After 2 h at 0 °C, the solvent was removed under
vacuum (10-3 mbar), and the residue was washed with small
amounts of cold pentane to leave complex 10a-pyr as an orange
1
powder (213 mg, 0.26 mmol, 53%). H NMR (399.8 MHz, CD2-
Cl2, 25 °C): δ 8.33 (m br, 2H, o-H pyr), 8.28 (s, 4H, 15-, 19-, 21-,
3
and 25-H), 8.02 (s, 2H, 17- and 23-H), 7.93 (dd, JHH ) 9.2 Hz,
4
4JHH ) 2.8 Hz, 1H, 4-H), 7.88 (d, JHH ) 2.8 Hz, 1H, 6-H), 7.68
(s br, 2H, 7-H and p-H pyr), 7.55 (m, 3H, 10-12-H), 7.20 (m br,
3
2H m-H pyr), 6.33 (d, JHH ) 9.2 Hz, 3-H), -0.98 (s, 3H, Ni-
CH3). 13C{1H} NMR (100.5 MHz, CD2Cl2, 25 °C): δ 171.2 (Cq,
C2), 168.2 (CH, C7), 150.9 (CH br, o-C pyr), 149.6 (Cq, C8), 141.0
and 133.0 (Cq each, C9, C13, C14, and C20), 137.1 (CH br, p-C
pyr), 135.5 (Cq, C5), 131.8 (CH, C6), 131.7 (q, 2JCF ) 33 Hz, C16,
C18, C22, and C24), 131.1 (CH, C10 and C12), 130.6 (CH br,
C15, C19, C21, and C25), 128.8 (CH, C4) 127.5 (CH, C11), 123.5
(q, 1JCF ) 272 Hz, 4 × CF3), 123.2 (CH br, m-C pyr), 122.6 (CH,
C3), 121.5 (m, CH, C17 and C23), 117.7 (Cq, C1), -7.3 (CH3,
Ni-CH3).
Complex 1a-pyr. Following the general procedure method A,
113 mg (186 µmol, 93%) of compound 1-pyr was obtained from
[(tmeda)NiMe2] (40.8 mg, 200 µmol), 2-anthracen-9-yl-6-[(2,6-di-
isopropylphenylimino)-methyl]-phenol (91.4 mg, 200 µmol), and
pyridine (240 mg, 3.04 mmol) in benzene as an orange-red powder.
1H NMR (399.8 MHz, C6D6, 25 °C): δ 8.16 (s, 1H, 21-H), 8.06
and 7.75 (d each, JHH ) 8.8 Hz, 2H each, 16-, 19-, 23- and 26-H),
7.79 (s, 1H, 7-H), 7.75 (m, 2H, o-H pyridine), 7.36 and 7.18 (d
3
each, JHH ) 7.2 Hz, each, 1H each, 4- and 6-H), 7.11 and 6.94
(m:t, JHH ) 7.4 Hz, 5:2H, 10-12-, 17-, 18-, 24-, and 25-H), 6.67
3
(vt, JHH ) 7.2 Hz, 1H, 5-H), 6.27 (vt br, JHH ) 7.2 Hz, 1H, p-H
pyridine), 5.61 (vt br, JHH ) 6.2 Hz, 2H, m-H pyridine), 4.26 (m,
i
3
2H, 2 × Pr), 1.44 and 1.12 (d each, JHH ) 7.2 Hz each, 6:6H, 2
× Pr), -0.80 (s, 3H, Ni-CH3). 13C{1H} NMR (100.5 MHz, C6D6,
i
25 °C): δ 166.5 (CH, C7), 166.2 (Cq, C2), 151.5 (CH, o-C
pyridine), 150.2 (Cq, C8), 141.2 (Cq, C9 and C13), 137.1 (CH each,
C4), 135.0 (p-C pyridine), 134.1 (CH, C6), 132.0 and 131.3 (Cq
each, C15, C20, C22, and C27), 131.0 (Cq, C3 and C14), 128.5
and 128.1 (CH each, C16, C19, C23, and C26), 126.5 (CH, C10
and C12), 125.6 (CH, C21), 123.6 (CH, C11), 122.2 (CH, m-C
Synthesis of Complex 11a-pyr. (a) Preparation of Salicylal-
dehyde 13. Following the general procedure for the synthesis of
salicylaldimines, condensation of terphenylamine 4a (518 mg, 1
mmol) with 3-(tert-butyl)alicylaldehyde (178 mg, 1 mmol) in 15
mL of methanol gave salicylaldimine 13 (589 mg, 0.87 mmol, 87%).
1H NMR (399.8 MHz, C6D6, 25 °C): δ 12.61 (s, 1H, OH), 7.68
(s, 4H, 15-, 19-, 21-, and 25-H), 7.56 (s, 2H, 17- and 23-H), 7.12
i
pyridine), 120.5 (Cq, C1), 113.7 (CH, C5), 28.5 (CH, 2 × Pr),
i
28.5 and 25.0 (CH3 each, 2 × Pr), -7.3 (CH3, Ni-CH3). Anal.
Calcd for C39H38N2ONi (609.43 g mol-1): C, 76.86; H, 6.28; N,
4.60. Found: C, 76.40; H, 6.71; N, 4.08.
3
4
(dd, JHH ) 7.6 Hz, JHH ) 1.6 Hz, 1H, 4-H), 6.93 (m, 4H, 7-H
and 10-12-H), 6.38 (vt, JHH ) 7.6 Hz, 5-H), 6.22 (dd, 3JHH ) 7.6
4
t
Hz, JHH ) 1.6 Hz, 1H, 6-H), 1.49 (s, 9H, Bu). 13C {1H} NMR
(100.5 MHz, C6D6, 25 °C): δ 170.9 (CH, C7), 160.9 (Cq, C2),
146.1 (Cq, C8), 141.2 and 132.1 (Cq each, C9, C13, C14, and C20),
138.2 (Cq, C3), 132.0 (q, 2JCF ) 33 Hz, C16, C18, C22, and C24),
131.9 (CH, C4), 131.0 (CH, C10 and C12), 130.6 (CH, C6), 130.2
(m br, CH, C15, C19, C21, and C25), 126.4 (CH, C11), 123.8 (q,
1JCF ) 271 Hz, 4 × CF3), 121.0 (m, CH, C17 and C23), 118.9
t
t
(CH, C5), 117.9 (Cq, C1), 35.0 (Cq, Bu), 29.3 (CH3, Bu). (b)
Preparation of Complex 11a-pyr. To a mixture of [(tmeda)Ni-
(CH3)2] (100 mg, 0.49 mmol) and salicylaldimine 13 (332 mg, 0.49
mmol) in a 25 mL Schlenk flask was added a solution of 0.5 mL
Synthesis of Complex 10a-pyr. (a) Preparation of Salicylal-
dehyde 12. Following the general procedure for the synthesis of

2362 Organometallics, Vol. 26, No. 9, 2007
Go¨ttker-Schnetmann et al.
of pyridine in diethyl ether (10 mL) at -30 °C under stirring. The
temperature was slowly raised to 0 °C under stirring, while the
color changed to orange-red. After 2 h at 0 °C, the solvent was
removed under vacuum (10-3 mbar), and the residue was washed
with small amounts of cold pentane to leave complex 11a-pyr as
an orange powder (343.8 mg, 0.295 mmol, 60%). 1H NMR (399.8
51 °C. After a total of 40 min stirring at 500 rpm, 40 bar of ethylene,
the reaction was quenched by terminating the ethylene flow,
carefully venting the reactor, and pouring the reaction mixture into
200 mL of technical grade methanol. The resulting mixtures
containing precipitated polyethylenes in case of complexes 1a-pyr,
7a-c-pyr, and 8a-c-pyr were stirred for 1 h at 20 °C, the polymer
collected by filtration, washed with 2 × 50 mL of methanol and
50 mL of acetone, and dried to constant weight under vacuum (50
°C, 20 mbar). In case of polyethylenes obtained with complexes
7d-f-pyr, 8d-g-pyr, workup was as follows: The homogeneous
solution was evaporated to dryness under reduced pressure (60-
80 °C, 500-20 mbar). To the resulting highly viscous orange-
yellowish oil was added methanol (10 mL), the resulting mixture
was vigorously stirred for 30 min at 55 °C, the mixture was cooled
to 0 °C, and the yellowish methanol phase was decanted. Finally,
residual solvent was removed at 50 °C, 20 mbar for 2 d.
Characterization data and yields are given in Table 4.
MHz, C6D6, 25 °C): δ 8.45 (m br, 2H, o-H pyr), 8.28 (s, 4H, 15-,
3
19-, 21-, and 25-H), 7.79 (s, 2H, 17- and 23-H), 7.10 (d, JHH
)
7.2 Hz, 1H, 4-H), 6.90 (m, 4H, 7-H and 10-12-H), 6.54 (m br,
3
1H, p-H pyr), 6.46 (d, JHH ) 7.2 Hz, 1H, 6-H), 6.27 (m br, 3H,
t
5-H and m-H pyr), 0.97 (s, 9H, Bu), -0.88 (s, 3H, Ni-CH3).
13C{1H} NMR (100.5 MHz, C6D6, 25 °C): δ 168.0 (CH, C7), 166.9
(Cq, C2), 151.2 (Cq, C8), 150.7 (CH, o-C pyr), 142.0 and 133.8
(Cq each, C9, C13, C14, and C20), 140.8 (Cq, C3), 136.1 (CH, p-C
pyr), 131.9 (CH, C6), 131.8 (q, 2JCF ) 33 Hz, C16, C18, C22, and
C24), 131.5 (CH, C4), 131.0 (CH, C15, C19, C21, and C25), 130.7
(CH, C10 and C12), 126.4 (CH, C11), 124.1 (q, 1JCF ) 271 Hz, 4
× CF3), 123.4 (CH, m-C pyr), 121.0 (CH, C17 and C23), 118.9
t
t
(Cq, C1), 113.9 (CH, C5), 34.5 (Cq, Bu), 28.9 (CH3, Bu), -8.1
(CH3, Ni-CH3).
Acknowledgment. Financial support by BASF AG is
gratefully acknowledged. S.M. is indebted to the Fonds der
Chemischen Industrie. We thank Lars Bolk for DSC and GPC
analyses.
General Procedure for the Polymerization of Ethylene in
Toluene. 95 mL of toluene was cannula-transferred to a 3×
evacuated and argon-filled reactor thermostated to 44 °C. The
solvent was saturated 3× with 5 bar of ethylene under stirring (500
rpm) over a total of 15 min. The reactor was vented with a slow
ethylene flow remaining (1.1 bar), and 5 mL of a toluene solution
containing 10 µmol of the respective catalysts 1a-pyr, 7-pyr, or
8-pyr was injected by syringe/Teflon-cannula. The injection-valve
was closed, and the reactor was pressurized with 40 bar of ethylene,
while the temperature rose to 49-51 °C within 2 min. The
temperature of the thermostate was adjusted to 48.5 °C, resulting
in a polymerization temperature in the reactor between 49.5 and
Supporting Information Available: Examples of 1H and
13C{1H} NMR spectra of new compounds and obtained polyeth-
ylenes, GPC traces, mass-flow traces, and CIF files containing the
X-ray diffraction analyses of complexes 7b-pyr (CCDC-629991)
and 8f-pyr (CCDC-629992). This material is available free of
charge via the Internet at http://pubs.acs.org.
OM0611498