Metallocene analogues containing bulky heteroallylic ligands and their use as new olefin polymerization catalysts

Article abstract of DOI:10.1016/S1381-1169(97)00209-4

A series of Ti and Zr metallocene analogues containing bulky benzamidinate ligands has been prepared and fully characterized. Treatment of TiCl₄(THF)₂ or ZrCl₄(THF)₂ with two equivalents of the appropriate benzamidinate anions affords the bis(benzamidinato) complexes [C₆H₅C(NC₃H₇)₂]₂MCl₂ (M=Ti (1), Zr (2)) and [C₆H₅C(NC₆H₁₁)₂]₂MCl₂ (M = Ti (3), Zr (4)). The zirconium complex 2 was structurally characterized by X-ray diffraction. In a similar manner the nonafluoromesityl derivative [(CF₃)₃C₆H₂C(NC₆H₁₁)₂]₂ZrCl₂ (5) was synthesized from ZrCl₄(THF)₂ and Li[(CF₃)₃C₆H₂C(NC₆H₁₁)₂]. Methylation of 4 with methyllithium yields the dimethyl complex [C₆H₅C(NC₆H¹¹)₂]₂ZrMe₂ (6). The mixed-ligand metallocene analogues [C₆H₅C(NC₃HT₇)₂](C₅Me₅)MCl₂ (M = Ti (7), Zr (8)) and [C₆H₅C(NC₆H¹¹)₂](C₅Me₅)TiCl₂ (9) have been prepared by reacting (C₅Me₅)TiCl₃ or (Cs₅Me₅)ZrCl₃ with one equivalent of a lithium N,N'-dialkytbenzamidinate. The polymerization of ethylene and propylene has been studied by the catalytic precatalyst complexes I and 2 upon reaction of an excess of methylalumoxane to obtain the active cationic complexes. The polymerization activity of the complexes is comparable to other benzamidinate ancillary containing ligands although toward shorter amounts of time due to a competitive inhibition presumably obtained by a β-hydrogen elimination from the ligand. Polymerization activity is strongly dependent on catalyst and cocatalyst concentrations and on temperature.

Full text of DOI:10.1016/S1381-1169(97)00209-4

Ž
.
Journal of Molecular Catalysis A: Chemical 130 1998 149–162
Metallocene analogues containing bulky heteroallylic ligands and
their use as new olefin polymerization catalysts
a
a
b
Joachim Richter , Frank T. Edelmann , Mathias Noltemeyer ,
b
c
c,)
Hans-Georg Schmidt , Michal Shmulinson , Moris S. Eisen
a
Chemisches Institut der Otto-Õon-Guericke-UniÕersitat Magdeburg, UniÕersitatsplatz 2, D-39106 Magdeburg, Germany
¨
¨
b
Institut fur Anorganische Chemie der UniÕersitat Gottingen, Tammannstr. 4, D-37ß77 Gottingen, Germany
¨
¨
¨
¨
c
Department of Chemistry, Technion-Israel Institute of Technology, 32000 Haifa, Israel
Received 27 March 1997; accepted 11 September 1997
Abstract
A series of Ti and Zr metallocene analogues containing bulky benzamidinate ligands has been prepared and fully
Ž
.
Ž
Ž
.
characterized. Treatment of TiCl4 THF or ZrCl4 THF with two equivalents of the appropriate benzamidinate anions
2
2
Ž
.
w
.2x
Ž
Ž .
Ž ..
w
Ž
.2x
affords the bis benzamidinato complexes C6H5C NC3H7 2MCl2 MsTi 1 , Zr 2 and C6H5C NC6H11 2MCl2
Ž
Ž .
Ž ..
MsTi 3 , Zr 4 . The zirconium complex 2 was structurally characterized by X-ray diffraction. In a similar manner the
wŽ
.
Ž
.2 x
Ž .
Ž
.
nonafluoromesityl derivative
CF3 3C6 H2C NC6 H11 2 ZrCl2
5
was synthesized from ZrCl4 THF
and
wŽ
.
Ž
. x
w
Ž
Ž .
.2x 2
Li CF3 3C6H2C NC6H11 . Methylation of 4 with methyllithium yields the dimethyl complex C6H5C NC6H11 2ZrMe2
2
Ž .
w
Ž
. xŽ
.
Ž
Ž ..
8
6 . The mixed-ligand metallocene analogues C6H5C NC3H7
C5Me5 MCl2 M s Ti 7 , Zr
and
2
w
Ž
. xŽ
.
Ž .
Ž
.
Ž
.
C6H5C NC6H11
C5Me5 TiCl2 9 have been prepared by reacting C5Me5 TiCl3 or C5Me5 ZrCl3 with one equivalent
2
of a lithium N,NY-dialkylbenzamidinate. The polymerization of ethylene and propylene has been studied by the catalytic
precatalyst complexes 1 and 2 upon reaction of an excess of methylalumoxane to obtain the active cationic complexes. The
polymerization activity of the complexes is comparable to other benzamidinate ancillary containing ligands although toward
shorter amounts of time due to a competitive inhibition presumably obtained by a b-hydrogen elimination from the ligand.
Polymerization activity is strongly dependent on catalyst and cocatalyst concentrations and on temperature. q 1998 Elsevier
Science B.V.
Keywords: Heteroallylic ligands; Metallocene analogues; Zirconium complexes; Olefin polymerization
1. Introduction
w
x
use of bulky heteroallylic ligands 1–3 , this
class of compounds has attracted considerable
Following our discovery that analogues of
metallocene catalysts can be obtained with the
Ž
interest. Especially the synthesis of bis benz-
amidinato metal dihalides of Ti, Zr, and Hf
.
)
appears to be a promising approach to new
Corresponding author. Tel.: q972-4-8292680; fax: q972-4-
w
x
classes of olefin polymerization catalysts 4–10 .
8233735; e-mail: chmoris@techunix.technion.ac.il
1381-1169r98r$19.00 q 1998 Elsevier Science B.V. All rights reserved.
Ž
.
PII S1381-1169 97 00209-4

(
)
150
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
Such complexes usually contain the benzamidi-
nate ligands in a chelating coordination mode:
In the solid state, both compounds form dimers
in which the metal atoms are connected via
chlorine bridges. In the same year Roesky et al.
described the preparation of disubstituted com-
plexes by simple treatment of the metal tetra-
X
Ž
.
chlorides with lithium-N,N -bis trimethylsilyl -
Ž
Ž ..
benzamidinate in a 1:2 molar ratio Eq. 3
w
x
20 :
2Li C H C NSiMe
3
2
qMCl4
Ž
.
6
5
™ C H C NSiMe
sTi, Zr
2MCl2 q2LiCl
M
Ž
.
6
5
3
2
X
In most cases the substituents R and R are
3
Ž .
alkyl, aryl or SiMe3, but examples with R and
T he X -ray diffraction studies of
X
R sH or NMe2 are also known. Typical syn-
thetic routes to such benzamidinato complexes
involve reactions of transition metal halides with
alkali metal benzamidinates 11–16 or the par-
ent amidines 17 . In some cases carbodiimides
have been employed as precursors in insertion
reactions. For example, bis cyclopentadienyl di-
phenylzirconium IV reacts with p-toluyl-
carbodiimide under formation of an N-aryl sub-
stituted zirconium benzamidinate complex Eq.
w
Ž
. x
C6H5C NSiMe3 2 2TiCl2 obtained by Roesky
w
x
e t a l.
2 0
a n d th e a n a lo g o u s
w
Ž
. x
C6H5C NSiMe3 2 2ZrCl2 obtained by Eisen et
w
x
w x
al. 5 revealed in both cases the presence of
monomeric molecules, in which the central metal
is octahedrally coordinated by the two chelating
benz-
w
x
Ž
.
Ž
.
amidinate ligands and two chlorine atoms. The
chlorine atoms in the metallocene dichloride
analogues can be replaced stepwise by s-alkyl
ligands. For example, the methyl derivatives
Ž
Ž ..
w x
18 :
1
w
Ž
.
2 x
Ž .
C H C N S iM e 3
2 M M e C l an d
6
w
5Ž
.
x
Ž
.
C6H5C NSiMe3 2 2MMe2 MsTi, Zr have
been synthesized by methylation of the chloro
precursors using either methyllithium or dimeth-
w
x
7,21 . Independently,
ylm agnesium
w
Ž
. x
C6H5C NSiMe3 2 2TiMe2 has been obtained
in a protolytic reaction by treatment of tetra-
X
Ž .
1
Ž
.
methyltitanium with N,N -bis trimethylsilyl -
benzamidine. The dimethyltitanium complex has
been structurally characterized by X-ray diffrac-
In the case of titanium and zirconium, benza-
midinate complexes containing N-trimethylsilyl
substituents form the most thoroughly investi-
gated class of compounds. The first examples
w
x
tion 21 .
Ž
.
Several N-silylated mono cylopentadienyl
benzamidinato complexes of group IV elements
have also been reported. Edelmann et al. pre-
pared the first mixed-ligand complex of this
w
x
were reported by Dehnicke et al. in 1988 19 .
Ž .
They were prepared according to Eq. 2 by
treatment of the metal tetrachlorides with
w
Ž
.
x
Ž
.
type, C6H5C NSiMe3 2 C5H5 TiCl2, by re-
X
Ž
equimolar amounts of N,N,N -tris trimethyl-
Ž
.
acting C5H5 TiCl3 with the corresponding
.
silyl benzamidine:
2C H C NSiMe N SiMe
3
2
w
x
sodium benzamidinate 22 , while Roesky et al.
p re p a re d th e d iflu o ro c o m p le x
MeOC6 H 4C NSiMe3
C5Me5 TiF3 and Li MeOC6H4C NSiMe3 2
q2MCl4
Ž
.
Ž
.
6
5
3
w
Ž
.
x
Ž
.
C5Me5 TiF2 from
™ C H C NSiMe
q2ClSiMe3 MsTi, Zr
MCl3
Ä
Ž
.
4
6
5
3
2
2
Ž
.
w 2
Ž
.
x
2
Ž .
w
x
23 . More recently, Green et al. described a

(
)
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
151
w
Ž
. x
straightforward synthetic route to metallocene
or Li C6H5C NC6H11 2 , respectively, afforded
w
Ž
.
x
analogues of the type C6H5C NSiMe3 2
the disubstituted complexes 1–4 as wine-red
Ž
.
w x
Ž
.
Ž
.
C5R5 MCl2 6 :
MsTi or yellow MsZr crystalline solids
Ž
Ž ..
Eq. 5 :
C R MCl qLi C H C NSiMe
Ž
.
Ž
.
5
5
3
6
5
3
™ C H C NSiMe
C R MCl qLiCl
Ž
.
Ž
.
6
5
3
5
5
2
2
RsH; MsTi, Zr, Hf
RsMe; MsTi, Zr
4
Ž .
Meanwhile several research groups have
demonstrated the utility of metallocene ana-
logues containing bulky heteroallylic ligands as
novel homogeneous catalysts. Catalyst systems
Ž
.
comprising bis benzamidinato zirconium
dichlorides have been found to catalyze the
polymerization of ethylene, propylene and
styrene, although the catalytic activities are gen-
erally significantly lower than those of compa-
Ž .
5
All four products are stable in air for several
days and they are thus significantly less sensi-
tive to hydrolysis than the corresponding N-tri-
methylsilyl derivatives. Full characterization by
w
x
rable metallocene derivatives 4–10 . A consid-
erable disadvantage is the pronounced
moisture-sensitivity of complexes containing
N-trimethylsilyl substituted benzamidinate lig-
ands. This is due to the inherent hydrolytic
instability imposed by the presence of several
Si–N bonds in the molecules. A suitable ap-
proach to hydrolytically more robust catalysts
appeared to be the use of N-alkylated benza-
midinate anions as ancillary ligands. In this
paper we report the synthesis of several titanium
Ž1
elemental analysis as well as IR and NMR H,
13
.
C spectroscopy is simple and straightforward.
EI mass spectra of the titanium complexes 1 and
Ž
3 show the molecular ions 1: mrz 524, 3:
.
mrz: 686 , whereas in the spectra of the zirco-
nium derivatives only fragment peaks due to the
benzamidinate ligands are observed. The most
prominent characteristic bands in the IR spectra
result from absorptions of the NCN chelate unit.
Ž
.
and zirconium bis benzamidinate as well as
mixed-ligand catalysts which display a greatly
improved hydrolytic stability due to the use of
N,N1-dialkylbenzamidinate anions as support-
ing ligands. In addition, catalytic activity studies
toward the polymerization of ethylene and
propylene promoted by complexes 1 and 2 are
presented.
1
These bands appear at 1635 and 1639 cmy as
1
antisymmetrical and at 1346 and 1349 cmy as
symmetrical NCN valence vibration.
2.2. Crystal structure determination of
[
(
)2 ] ( )
C6 H5C NC3 H7 2 ZrCl2 2
The crystallographic data for complex 2 are
given in Tables 1, 3 and 4. Suitable single
crystals of 2 were obtained by the slow cooling
of a saturated solution in toluene from 208C to
y258C. Fig. 1 shows the structure of the
monomeric molecule. The central Zr atom is
octahedrally surrounded by two chelating benz-
amidinate ligands and two terminal chlorine
2. Results and discussion
(
)
(
2.1. Preparation of bis benzamidinato metal
[
(
)2 ]
dichlorides, C6 H5C NC3 H7 2 MCl2 MsTi
( ) ( )) ) ]
[
(
(
M
1 , Zr 2 and C6 H5C NC6 H11 2 2 MCl2
( ) ( ))
sTi 3 , Zr 4
Ž
.
Ž
.
Ž
Ž
..
Reactions of TiCl4 THF and ZrCl4 THF
atoms. One chlorine atom Cl 1a and one
2
w
2
Ž
.
2 x
Ž Ž ..
with two equivalents of Li C6H5C NC3H7
nitrogen atom of a chelate unit N 2a are in

(
)
152
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
the axial positions, while the second Cl atom
and the remaining nitrogen atoms occupy the
equatorial positions. As a result the C–N bond
lengths of the two chelate units are slightly
Especially remarkable is the large torsion angle
between the two planar ZrCN2 rings, which are
almost perpendicular with respect to each other
Ž
.
89.28 . This situation obviously minimizes re-
Ž
.
different 132 and 135 pm . The identical Zr–N
pulsion between the bulky isopropyl groups in
the molecule, as illustrated in Fig. 2. The tor-
sion angles between the phenyl rings and the
ZrCN2 planes are 89.38, which is the highest
value found for any metal benzamidinate com-
Ž
.
distances 221 and 222 pm are somewhat longer
than in the dimeric zirconium benzamidinate
w
w
w
Ž
.
x
Ž
.
C6H5C NSiMe3 2 ZrCl3 2 214 and 219 pm
x
19 though alike in the monomeric
Ž
.
x
Ž
.
w x
w Ž
. x
C6H5C NSiMe3 2 2ZrCl2 220 and 224 5 .
plex. In C6H5C NSiMe3 2 2SbCl2 this torsion
Table 1
Bond lengths pm and angles 8 for complex 2
Ž . Ž . Ž .
Ž
.
Ž .
Ž . Ž .
Zr 1 –N 1 a1
Ž . Ž .
Zr 1 –N 2
Ž .
220.8 4
Ž .
222.0 4
Zr 1 –N 1 220.8 4
Ž . Ž .
Ž .
Zr 1 –N 2 a1 222.0 4
Ž .
Ž .
Ž
.
Ž .
Ž . Ž .
Zr 1 –C 1
Ž . Ž
N 1 –C 11
Ž .
Ž
.
Zr 1 –Cl 1 a1
240.99 14
Zr 1 –Cl 1
240.99 14
Ž . Ž .
Ž .
Ž .
Zr 1 –C 1 a1
Ž . Ž .
264.8 4
264.8 4
Ž .
134.6 6
Ž .
131.5 6
.
.
Ž .
147.2 6
Ž .
146.2 7
N 1 –C 1
Ž . Ž .
N 2 –C 1
Ž .
N 2 –C 21
Ž
Ž . Ž .
C 1 –C 2
Ž .
149.5 7
Ž . Ž .
Ž . Ž .
C 3 –C 4
Ž . Ž .
C 5 –C 6
Ž .
138.4 7
C 2 –C 7
Ž . Ž .
Ž .
Ž .
C 2 –C 3
139.1 7
138.1 7
Ž . Ž .
Ž .
137.3 8
Ž .
137.0 8
C 4 –C S
Ž . Ž .
Ž .
Ž . Ž
.
.
Ž .
C 6 –C 7
139.1 7
C 11 –C 13
150.9 8
Ž
.
.
Ž
Ž
.
.
Ž .
151.3 8
Ž .
153.6 11
Ž
.
Ž
Ž .
150.3 10
C 11 –C 12
C 21 –C 22
Ž
C 21 –C 23
Ž .
Ž . Ž .
Ž .
Ž .
Ž . Ž .
Ž .
100.0 2
N 1 –Zr 1 –N 1 a1
Ž . Ž . Ž .
153.5 2
N 1 –Zr 1 –N 2 a1
Ž
.
Ž . Ž .
.
Ž
.
N 1 a1–Zr 1 –N 2 a1
Ž . Ž . Ž .
60.05 14
N 1 –Zr-1 –N 2
Ž . Ž . Ž .
60.05 14
Ž .
Ž .
N 1 a1–Zr 1 –N 2
Ž . Ž . Ž .
100.0 2
N 2 a1–Zr 1 –N 2
Ž . Ž . Ž .
89.2 3
Ž
.
.
.
.
Ž
.
.
.
.
N 1 –Zr 1 –Cl 1 a1
Ž . Ž . Ž .
104.35 11
N 1 a1–Zr 1 –Cl 1 a1
Ž . Ž . Ž .
93.16 10
Ž
Ž
92.90 14
N 2 a1–Zr l –Cl 1 a1
Ž . Ž . Ž .
153.04 12
N 2 –Zr 1 –Cl 1 a1
Ž . Ž . Ž .
Ž
Ž
N 1 –Zr 1 –Cl 1
Ž . Ž .
93.16 10
N 1 a1–Zr 1 –Cl 1
Ž . Ž . Ž .
104.35 11
Ž .
Ž
Ž
N 2 a1–Zr 1 –Cl 1
Ž . Ž . Ž .
92.90 14
Ž .
N 2 –Zr 1 –Cl 1
Ž . Ž . Ž .
153.04 12
Ž .
Cl 1 a1–Zr 1 –Cl 1
Ž . Ž . Ž .
97.14 9
N 1 –Zr 1 –C 1 a1
Ž . Ž . Ž .
128.6 2
Ž .
Ž
.
N 1 a1–Zr 1 –C 1 a1
Ž . Ž . Ž .
30.49 14
Ž .
N 2 a1–Zr 1 –C 1 a1
Ž . Ž . Ž .
29.7 2
Ž
.
.
N 2 –Zr 1 –C 1 a1
Ž . Ž . Ž .
97.4 2
Cl 1 a1–Zr 1 –C 1 a1
Ž . Ž . Ž .
123.64 11
Ž
.
Ž
Cl 1 –Zr 1 –C 1 a1
Ž . Ž . Ž .
97.65 11
N 1 –Zr 1 –C 1
Ž . Ž . Ž .
30.49 14
Ž .
97.4 2
Ž .
N 1 a1–Zr 1 –C 1
Ž . Ž . Ž .
128.6 2
Ž .
N 2 a1–Zr 1 –C 1
Ž . Ž . Ž .
Ž
.
N 2 –Zr 1 –C 1
Ž . Ž . Ž .
29.7 2
Cl 1 a1–Zr 1 –C 1
Ž . Ž . Ž .
97.65 11
Ž .
117.4 2
Ž
.
Cl 1 –Zr 1 –C 1
123.64 11
C 1 a1–Zr 1 –C 1
Ž . Ž . Ž .
Ž . Ž .
Ž
.
Ž .
Ž .
93.2 3
Ž .
123.5 5
Ž .
142.5 4
C 1 –N 1 –C 11
Ž . Ž .
122.7 4
Ž .
C 1 –N 1 –Zr 1
Ž . Ž . Ž .
Ž
.
C 11 –N 1 –Zr 1
Ž . Ž . Ž .
141.5 3
C 1 –N 2 –C 21
Ž . Ž .
Ž .
93.5 3
Ž .
C 1 –N 2 –Zr 1
C 21 –N 2 –Zr 1
Ž . Ž . Ž .
Ž .
122.9 4
Ž .
56.4 2
Ž . Ž . Ž .
Ž .
56.8 2
Ž .
174.3 3
N 2 –C 1 –N 1
Ž . Ž . Ž .
112.7 4
Ž .
N 2 –C 1 –C 2
Ž . Ž . Ž .
124.4 4
Ž .
N 1 –C 1 –C 2
Ž . Ž . Ž .
N 2 –C 1 –Zr 1
Ž . Ž . Ž .
N 1 –C 1 –Zr 1
C 2 –C 1 –Zr 1
Ž . Ž . Ž .
C 3 –C 2 –C 1
Ž .
120.7 4
Ž . Ž . Ž .
C 4 –C 3 –C 2
Ž .
120.2 4
Ž .
119.8 4
C 7 –C 2 –C 3
Ž . Ž . Ž .
119.0 5
Ž .
C 7 –C 2 –C 1
Ž . Ž . Ž .
Ž . Ž . Ž .
Ž .
Ž .
120.1 5
Ž . Ž . Ž .
Ž . Ž . Ž .
C 2 –C 7 –C 6
Ž .
Ž .
120.4 5
C 5 –C 4 –C 3
120.9 5
C 6 –C 5 –C 4
119.7 5
Ž . Ž . Ž .
C 5 –C 6 –C 7
Ž .
Ž
.
Ž
.
Ž .
Ž .
Ž
Ž
.
.
Ž
Ž
.
.
Ž .
N 1 –C 11 –C 13
110.7 5
N 1 –C 11 –C 12
Ž .
110.0 4
Ž
.
Ž
.
Ž
.
Ž .
Ž .
110.8 6
Ž .
110.5 5
C 13 –C 11 –C 12
Ž .
111.9 5
Ž .
N 2 –C 21 –C 22
Ž
.
Ž
.
Ž
.
Ž
.
Ž .
N 2 –C 21 –C 23
108.6 6
C 22 –C 21 –C 23
Symmetric transformation for the equivalent atoms: a1 yx, y, yzq1r2.

(
)
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
153
Table 2
Activity data for the polymerization of ethylene and propylene by bis benzamidinate zirconium and titanium complexes
Ž
.
b
c
Catalysta
T
8C
Cat
Al:M ratio
a-olefin
Activityd
mp 8C
Ž
.
w
x
w x
Co-cat
Ž
.
Entry
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
2
2
2
2
2
2
2
2
1
2
2
2
2
2
25
0
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
4.4=10y4
0.088
0.352
0.088
0.176
0.352
0.880
0.176
0.352
0.440
0.880
0.176
0.176
0.440
1.760
0.440
0.880
200
800
200
400
800
2000
400
800
1000
2000
400
ethylene
ethylene
ethylene
ethylene
ethylene
ethylene
ethylene
ethylene
ethylene
ethylene
propylene
propylene
propylene
propylene
propylene
propylene
1.2=105
1.4=104
6.8=103
3.4=104
5.6=104
6.0=104
8.6=104
2.1=105
1.8=105
4.0=105
9.5=103
6.8=103
1.4=104
2.1=104
2.1=104
1.4=104
129.8
135.7
136.6
133.3
133.4
134.4
130.9
131.8
131.7
133.0
25
25
25
25
60
60
60
60
25
25
25
25
60
60
400
1000
4000
1000
2000
a Polymerization times5 min.
bw
cw
x
Catalyst , M in toluene.
y6
x
Ž
.
w
x
Co-catalyst , M in toluene, methylaluminoxane, solvent removed from a 20% solution in toluene Schering at 258Cr10 Trr monomer ,
pressures1 atm.
dGrams total polymerrmol Zr atm ethylene h.
Table 3
Crystal data, data collection and refinement for 2
Empirical formula
Formula weight
Temperature
C26 H38Cl2 N4 Zr
568.72
Ž .
223 2 K
Wavelength
Crystal system
Space group
71.073 pm
orthorhombic
Pbcn
Ž .
Unit cell dimensions
as2047.7 5 pm
Ž
.
bs851.110 10 pm
Ž .
cs1685.3 4 pm
3
Ž
.
Volume
2.9371 11 nm
Z
4
1.286 mgrm3
Ž
.
Density calculated
Absorption coefficient
0.576 mmy1
Ž
.
F 000
1184
Crystal size
0.90=0.70=0.20
u-range for data collection
Index ranges
3.54 to 22.488
y22FhF22, y1FkF9, y18FlF18
2248
Reflections collected
Independent reflections
Refinement method
Datarrestraintsrparameters
Goodness-of-fit on F2
Final R indices:
Ž
.
1902 Rint s0.0544
full-matrix least-squares on F2
1898r0r154
1.118
w
Ž .x
R1 I)2s I
wR2
0.0581
0.1489
Ž
.
R indices all data :
R1
0.0652
wR2
0.1644
Largest difference peak
Largest difference hole
1196 e nmy3
y757 e nmy3

(
)
154
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
Table 4
4
Ž
.
Atomic coordinates =10 and equivalent isotropic displacement
parameters pm =10
2
y1
Ž
.
for complex 2
Ž .
U eq
X
Y
Z
Ž .
Zr 1
Ž .
517 1
Ž .
2500 1
Ž .
79 1
0
40 1
Ž .
Ž .
Ž .
Ž .
Ž .
Cl 1
375 1
y1356 2
3471 1
Ž .
N 1
Ž .
N 2
Ž .
1001 2
Ž .
157 2
Ž .
Ž .
2115 2
Ž .
1595 3
Ž .
1111 4
45 1
Ž .
Ž .
2374 5
60 1
Ž .
C 1
Ž .
C 2
Ž .
791 2
Ž .
1239 2
Ž .
Ž .
2906 5
Ž .
1562 3
Ž .
980 3
Ž .
Ž .
45 1
2133 5
46 1
Ž .
C 3
Ž .
1372 3
Ž .
Ž .
2933 6
Ž .
251 3
Ž .
Ž .
61 1
2208 6
57 1
Ž .
Ž .
Ž .
Fig. 2. Side view of the molecular structure of complex 2.
C 4
1793 3
y274 3
Ž .
C 5
Ž .
C 6
Ž .
2084 1
Ž .
1945 3
Ž .
Ž .
Ž .
4339 6
y88 3
57 1
Ž .
Ž .
5053 7
Ž .
621 3
59 1
Ž .
C 7
Ž .
1525 2
Ž .
Ž .
504 6
Ž .
1159 3
Ž .
Ž .
54 1
4336 6
55 1
Ž
.
.
.
.
.
.
Ž .
Ž .
C 11
1674 2
2133 3
Ž
.
ubstitution product 5 in low yield 24% as a
cream-colored solid which decomposes at 1618C
Ž
Ž .
1682 3
Ž .
Ž .
1889 4
Ž .
C 12
y1207 7
81 2
Ž
Ž .
Ž .
749 8
Ž .
Ž .
C 13
1976 3
2940 4
76 2
Ž .
Ž
Ž .
y191 3
Ž .
Ž .
1063 4
C 21
3442 8
86 2
Ž
Ž ..
Eq. 6 .
Ž
Ž .
Ž
.
Ž .
Ž .
C 22
y552 4
2539 11
Ž .
434 4
109 3
Ž .
Ž
Ž .
Ž .
1557 5
C 23
y667 4
4437 7
103 3
U
is defined as one third of the trace of the orthogonalized U
i j
eq
tensor.
w
x
Ž . Ž .
angle is 88.98 24 . With 112.78 the N 1 –C 1 –
Ž .
N 2 is slightly smaller than the comparable
w
Ž
.
x
Ž
. w x
angle in C6H5C NSiMe3 2 ZrCl3 2 114.98 19
or in C6H5C NSiMe3 2 ZrCl2 114.78 5 .
Ž
.
Ž
.
w x
[(
)
CF3 3 C 6 H 2 C
2.3. Preparation of
) ] ( )
Ž .
6
(
NC6 H11 2 2 ZrCl2
5
Ž
.
2
Similar treatment of ZrCl4 THF with the
The low yield is due to the formation of large
nonafluoromesityl substituted lithium-N,NX-di-
amounts of oily by-products. Purification of the
crude material can only be achieved by recrys-
tallization from hexane, which results in consid-
erable losses due to the high solubility of 5.
w
Ž
.
cyclohexylbenzamidinate Li CF3 3C6 H 2C
NC6H11 2 molar ratio 1:2 afforded the dis-
Ž
.
x
Ž
.
[
(
) ]
2.4. Preparation of C6 H5C NC6 H11 2 2 ZrMe2
( )
6
The chlorine atoms in 4 are readily replaced
by methyl groups upon treatment with two
Ž
Ž ..
equivalents of methyllithium Eq. 7 . The re-
action proceeds smoothly in diethylether and
affords the dimethyl derivative 6. The product
melts at 1358C without decomposition, indicat-
ing a higher thermal stability than the dichloride
precursor. A similar observation has earlier been
Fig. 1. The molecular structure of 2 showing the atom numbering
scheme.

(
)
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
155
reported for the dimethylzirconium complex
substituted counterparts. Crystals of 7–9 are
stable in air for several days. They are highly
soluble in THF or toluene, and moderately solu-
ble in hexane.
Žt
.
w x
Bu3CO ZrMe2 25 .
2
2.6. Polymerization actiÕity studies
The catalytic polymerization of ethylene and
propylene were studied using the catalytic pre-
cursors 1 and 2. Cationic catalysts were gener-
ated by the reaction of the corresponding com-
Dichloro or dialkyl complexes such as 1–6
plexes with methylaluminoxane MAO 1. For
the dimethyl analogue of complex 2, the cationic
active species was determined spectroscopically
by reacting the dimethyl complex with an ex-
Ž
.
are useful precursors for the generation of
w
xq
cationic zirconium alkyls of the type L2 ZrR ,
Ž
.
w
x
which are catalytically active vide-infra 5,26 .
Ž
.
cess of MAO or B C6F5 3 in an NMR tube. The
2 . 5 .
[
P r e p a r a t i o n
) ](
o f
( )
Ž
.
methyl Zr- CH3 2 signal at 44.3 ppm in the
C-NMR shifts toward 62.3 ppm in the Zr-
CH3 similar to other cationic signals found
for resembling cyclopentadienyl complexes .
(
)
(
C6 H5C NC3 H7
C5 Me5 MCl2 MsTi 7 ,
13
2
w
( ))
[
(
) ](
)
Zr 8 and C6 H5C NC6 H11 2 C5 Me5 TiCl2
Ž
.
xq
( )
9
2
Ethylene and propylene polymerizations were
Another goal of this study was the prepara-
c a r r ie d
o u t u n d e r v ig o r o u s ly
tion of mixed-ligand complexes of Ti and Zr
containing both pentamethylcyclopentadienyl
and the N-alkylated benzamidinate ligands. The
anaerobicranhydrous vacuum line conditions,
and reactions were quenched after measured
time intervals with methanolrHCl solutions
prior to polymer collection, washing with pen-
tane and acetone and drying. Polymer mi-
crostructure of the obtained high density poly-
ethylene or atactic polypropylene were charac-
terized by 13C NMR using standard analysis
Ž
.
reactions between C 5 Me5 TiCl3 and
2 x
Ž
.
w
Ž
.
C5Me5 ZrCl3 with Li C6H5C NC3H7
Li C6H5C NC6H11 2 were carried out in THF
solution according to Eq. 8 . THF is known to
or
w
Ž
. x
Ž .
be a suitable solvent especially for reactions
Ž
.
with C5Me5 ZrCl3 as it forms the stable
w
x
46 .
Several interesting trends are evident in the
Ž
.
Ž
. w x
monomeric adduct C5Me5 ZrCl3 THF 27 .
Ž
.
ethylene polymerization data Table 2 . The ac-
tivity of the catalysts is strongly dependent on
Ž
.
the temperature entries 2, 5 and 8 . Thus, rais-
ing the temperature from 0 to 608C induces an
increase in catalytic activity by a factor of 15
Ž
.
and lowers the melting point smaller chains of
1 The polymerization of either ethylene or propylene by com-
The mixed ligand complexes 7–9 were iso-
Ž
.
Ž
.
plex 6 activated by either MAO or B C6 F5 gave similar poly-
lated in the form of red MsTi or yellow
3
merization results as those obtained for ethylene or propylene with
Ž
.
MsZr crystals. As expected, these com-
complex 2 and MAO.
2 For recent reviews on olefin polymerization catalysts, see
plexes exhibit a significantly higher hydrolytic
stability as compared to their N-trimethylsilyl
w
x
w
x
Refs. 28–34 . For some recent references, see 35–45 .

(
)
156
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
the polymer. Large effects have been also ob-
time used for the polymerization was 5 min.
Larger polymerization periods of time does not
achieve more polymer. This result indicates that
besides the b-methyl elimination pathway,
which presumably is the major chain termina-
tion process, a competitive deactivating path-
way is taking place inhibiting polymer forma-
tion. We believe that the competitive b-hydro-
gen elimination pathway from the ancillary lig-
and is responsible for this deactivation of the
catalyst. A simple comparison in the poly-
merization of either propylene or ethylene, of
Ž
served for the Al:Zr ratio compare entries 3–6
.
or 7–10 . Increasing the Al:Zr ratio results in a
general increase in the catalytic activities reach-
ing a plateau limit with larger excess of MAO.
This leveling behavior obtained by adding large
excess of MAO and increasing the ratio Al:Zr is
opposite to the behavior found by the analogue
cyclopentadienyl early transition metal systems,
in which the larger the ratio Al:Zr the larger the
w
x
catalytic activity is observed 35–53 . This re-
sult can be rationalized by the known effects of
the cocatalyst concentration catalyzing different
possible eliminations, alkyl transfer pathways
Ž
.
catalyst 2 with the bis silylated benzamidinate
w
Ž
. x
zirconium dichloride C6H5C NSiMe3 2 2 ZrCl2
3
w x
and other deactivation processes . In addition,
complex 5 in which no b-hydrogens are pre-
the metal effect on these benzamidinate ancil-
lary ligands is shown by comparing the catalytic
precursor 1 and 2. The titanium complex has
been found to be a slightly better catalyst than
the analogous zirconium complex. This similar
behavior has been encountered in the poly-
merization of ethylene and propylene by
sent at the ancillary ligands, shows that for the
latter, the catalytic activity is similar to that
observed for complex 2, though the catalyst is
able to polymerize the a-olefins for long peri-
ods of time.
It is very interesting to compare some of our
results with similar catalytic polymerization sys-
tems containing the benzamidinate ancillary lig-
ation. For example, reactions of mixed cy-
clopentadienyl-benzamidinate titanium dichlo-
w
x
bisamido ancillary ligands 56 .
The polymerization of propylene to atactic
polypropylene by the catalytic complexes 1 and
2 resembles the same features obtained for ethy-
lene. For polypropylene, the proton and carbon
spectroscopic analyses of the polymers reveal
only vinylriso-propyl end groups with no
Ž
.
rides and a large excess of MAO AlrTis839
have shown an ethylene catalytic activity of
y
1
0.6=105 g polymer mol Ti
hy1 atmy1
.
Ž
.
Similar mixed system of zirconium dimethyl
Ž
Ž
.
vinylidenern-propyl end groups characteristic
with B C6F5 3 as cocatalyst has a smaller activ-
NMR for the obtained polymer structure is given
ity compared to the corresponding Ti of 1.2=
4
y1
.
Ž
.
in Section 3 similar to the polymers obtained
10 g polymer mol Zr
hy1 atmy1, presum-
by Cp2) MMeq MsZr, Hf systems 57,58 .
Polymers containing these end-groups may be
formed at least from three different theoretical
mechanisms. The first, involves an allylic C–H
ably due to the production of the inert pentaflu-
Ž
.
w
x
w
x
orophenyl side complex 60,61 . The use of
these hard basic benzamidinate ligands replac-
ing both cyclopentadienyl groups stems from
the fact that these are electron withdrawing
ancillary ligands which should enhance the elec-
w
x
activation of propylene 59 , the second, in-
w
x
volves a b-methyl elimination 59 , and thirdly,
a b-hydrogen elimination from a polymer chain
in which the last inserted monomer inserts in a
2–1 fashion. The last mechanism in our case
can be rejected since no n-propyl end groups
are observed. Noteworthy to point out, that the
Ž
trophilic character of the metal center as found
for the methyl signal in the 13C-NMR, 62.3
ppm, of the respectively cationic Zr–Meq com-
.
plex . These benzamidinate systems are 4 elec-
tron donating groups with 2 coordination sites
whereas the cyclopentadienyl ligand is a 6 elec-
tron donating and 3 coordination site system.
3
Ž .
w
x
Comparing the results of mixed systems Zr, Ti
For a summary on reaction pathways, see Refs. 54,55 .

(
)
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
157
to those obtained in Table 2, it is evident that
3. Experimental part
two benzamidinate ligation groups have a mod-
erately improved catalytic reactivity. It is impor-
tant to point out, that both systems have lower
catalytic reactivity than the analogous cyclopen-
All manipulations of air-sensitive materials
were performed with the rigorous exclusion of
oxygen and moisture in flamed Schlenk-type
glassware on a dual manifold Schlenk line, or
tadienyl systems for the polymerization of ethy-
7
lene or propylene 1=10 and 6=106
g
Ž
y
5
Ž
.
interfaced to a high vacuum 10 Torr line, or
in a nitrogen filled vacuum atmospheres glove
y
1
mol Zr
hy1 atmy1, for ethylene and propy-
lene, respectively 31 despite the larger cat-
alytic activity which has been observed, for
Ž
.
w
x.
Ž
box with a medium capacity recirculator 1–2
.
ppm O2 . Argon and nitrogen were purified by
Ž
.
example, in the bis benzamidinate yttrium-
passage through a MnO oxygen-removal col-
w x
catalyzed oligomerization of alkynes 4 .
˚
umn and a Davison 4 A molecular sieve col-
The difference in catalytic activity of our
‘cationic’ complexes compared with the cy-
clopentadienyl ‘cationic’ systems can be ratio-
nalized by the structural environment of the
metal center. Normally, it has been observed
that the smaller the angle between the ancillary
ligands, the more coordinatively unsaturated the
metal center of the complex and the better the
umn. Ether solvents were distilled under argon
from sodium benzophenone ketyl. Hydrocarbon
Ž
.
solvents toluene-d8, C6D6, hexane were dis-
tilled under nitrogen from NarK alloy. All
solvents for vacuum line manipulations were
stored in vacuo over NarK alloy in resealable
Ž
.
bulbs. Nitrile compounds Aldrich were de-
gassed and freshly distilled under argon. NMR
spectra were recorded on a Bruker AM 200
4
catalytic activity observed for the catalyst ,
although, in our case, we have a catalyst with
lesser reactivity in the catalytic polymerization
of ethylene than the analogous cyclopentadienyl
complexes. This activity–structure relationship
for complex 2 can be simply illustrated by the
spectrometer. Chemical shifts for H- and 13C-
1
NMR are referenced to internal solvent reso-
nances and are reported relative to tetramethyl-
silane. The NMR experiments were conducted
Ž
.
on teflon valve-sealed tubes J-Young after
vacuum transfer of the solvent in a high vacuum
line.
fact that the small angle tilted to the back of the
X
w
Ž .
Ž . Ž
.
Ž . x
molecule N 2 –Zr 1 – N2 s89.2 3 8 will
prevent the approach of the olefin from the back
similarly to the cyclopentadienyl case, although
Ž .
Ž .
the presence of the large angle N 1 –Zr 1 –
(
)
3.1. Reactions of MCl4 MsTi, Zr with
Ž .X
Ž .
N 1 s153.5 2 with the two isopropyl equato-
rial groups congest the approach from the side
of the molecule, which may induce the low
catalytic activity. This side approach is believed
to be responsible for the catalytic polymeriza-
tion activity of the metal center which is gov-
erned by the 4 center transition state mecha-
[
(
)2 ]
[
and Li C 6 H5 C
Li C 6 H5 C NC3 H 7
) ] (
(
)
NC6 H11 2 general procedure
To a stirred solution of the given amount of
Ž
.
Ž
.
TiCl4 THF or ZrCl4 THF in 130 ml THF is
2
2
added dropwise at room temperature over a
period of 15 min a solution of the lithium
5
nism .
Ž
.
benzamidinate molar ratio 1:2 in 100 ml THF.
The reaction mixture is stirred overnight at room
temperature. The solvent is removed in vacuum,
the residue is extracted with 80 ml of toluene
and precipitated LiCl is removed by filtration
through a thin layer of Celite filter-aid. The
clear filtrate is evaporated to dryness, washed
4
w
x
For some recent references, see 62–65 .
5 For representative theoretical studies on Ziegler Natta poly-
merizations, see Refs. 66–75 .
w
x

(
)
158
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
1
Ž
.
x
Ž
.
Ž
with hexane 20–30 ml and dried under vac-
45% . H NMR THF-d8 : d 7.55 m, 6 H,
Ž
.
.
Ž
.
w
uum 12 h .
C6H5 , 7.25 m, 4 H, C6H5 , 3.30 sept, 4 H,
3
Ž
.
x
w
C H CH3 2, JH – H s7.2 Hz , 1.28 d, 24 H,
X
CH C H3 2, JH – H s7.2 Hz ppm. 13C NMR
3
(
Ž
.
x
Ž
.
3.2. Dichloro-bis N,N -diisopropylbenzami-
( ) ( )
)
Ž
Ž
.
w
.
x
dinato titanium IV
1
THF-d8 : d 180.8 C6H5C NC3H7 , 131.6
.
Ž
2 Ž
.
C6H5, Cipso , 130.4 C6H5 , 129.8 C6H5 ,
. x
126.8 C6 H 5 , 50.4 C H CH 3 ,
2
CH CH3 2 ppm.
Due to some sensitivity of the compound to
moisture and oxygen, a suitable crystal for X-ray
analysis was placed inside a glovebox into Kel-F
Ž
.
.
Ž
.
w
Ž
The reaction of 6.68 g 20.0 mmol
25.0
Ž
.
Ž
w
Ž
. x
TiCl4 THF
with 8.41
2 x
g
40.0 mmol
2
w
Ž
.
Ž .
Li C6H5C NC3H7
the wine-red product, m.p. 1038C. Found: C
58.7, H 7.1, N 10.1; calc. for C26H38Cl2 N4Ti
affords 7.12 g 68% of
Ž
.
Ž
.
525.40 : C 59.4, H 7.3, N 10.7%. IR: 1636 m,
Oil Voltalef . Then, it was mounted on the four
cycle diffractometer where it met a cold stream
of nitrogen at 223 K. Reflections were collected
on a Siemens P4 automated four cycle diffrac-
tometer. Intensities were corrected in the usual
way except for absorption. The structure was
solved by direct methods, and refined, based on
F2, by full matrix least-squares procedures. All
non-hydrogen atoms were refined with
anisotropic temperature coefficients. The hydro-
gen atoms were included by use of a riding
1342 m, 1217 m, 1170 m, 1157 m, 1137 m,
1075 m, 1014 s, 974 m, 938 w, 919 w, 892 w,
846 w, 702 m, 541 w, 496 w, 435 w cmy1. MS:
w
5
Ž
x
w
x
mrz 524 M, 2% , 509 M-CH3, 7% , 321
w
w
w
Ž
.
,
2
x
1 4 % , 2 0 3
M -C H C N C H
6
3
7
.
x
4 3 % , 1 4 6
C
6 H 5 C N C 3 H
,
7
2
x
Ž
.
w
C6 H5C NC3H7 , 25% , 104 C6 H5CNH,
100% . H NMR THF-d8, 200.13 MHz : d
1
x
Ž
.
Ž
.
Ž
Ž
.
x
7.55 m, 6 H, C6H5 , 7.28 m, 4 H, C6H5 ,
3
w
w
.
3.45 sept, 4 H, C H CH3 , JH – H s7.5 Hz ,
3
Ž
.
x
JH – H s7.5 Hz
Ž
.
1.35 d, 24 H, CH C H3 2
,
model and refined isotropically. The d C–H
ppm. 13C NMR
CDCl3
d
176.9
˚
˚
Ž
.
:
used was 0.95 A for the aromatic and 0.98 A for
the methyl hydrogens. Preliminary data, mea-
surement conditions and structure refinement
are summarized in Table 3. Final atomic coordi-
nates are given in Table 4. Additional material
available from the Cambridge Crystallographic
Data Center comprises thermal parameters hy-
drogen coordinates and the structural factors.
w
Ž
.
x
Ž
.
.
C6H5C NC3H7 , 129.9 C6H5, Cipso , 129.6
Ž
.
Ž 2
.
Ž
C6H5 , 128.7 C6H5 , 128.5 C6H5 , 126.5
C6H5 , 126.0 C6H5 , 52.4 CH CH3 2 , 23.9
Ž
.
Ž
.
w
Ž
. x
w
Ž
. x
CH CH3 2 ppm.
X
(
3.3. Dichloro-bis N,N -diisopropylbenzami-
( ) ( )
)
dinato zirconium IV
2
X
Ž
.
.
(
The reaction of 7.54 g 20.0 mmol
3.4. Dichloro-bis N,N -dicyclohexylbenzami-
Ž
.
Ž
)
( ) ( )
ZrCl4 THF
with 8.41
2 x
g
40.0 mmol
gave 6.78 g 60% of a
pale yellow, crystalline powder, m.p. 858C
dec. . Found: C 54.0, H 6.3, N 9.5; calc. for
C26H38Cl2 N4Zr 568.75 : C 54.9, H 6.7, N
9.9%. IR: 3067 m, 1639 m, 1578 w, 1507 m,
1417 s, 1343 s, 1219 m, 1172 m, 1140 m, 1127
dinato titanium IV
3
2
w
Ž
.
Ž .
Li C6H5C NC3H7
Ž
.
Ž
.
.
From 5.27 g 15.8 mmol TiCl4 THF and
Ž
.
Ž
.
w
Ž
2x
9.18 g 31.8 mmol Li C6H5C NC6H11 2 are
Ž
.
Ž
.
isolated 6.87 g 64% of a wine-red, crystalline
Ž
.
solid, m.p. 1288C dec. . Found: C 65.8, H 7.5,
Ž
.
N 7.8; calc. for C38H34Cl2 N4Ti 685.66 : C
66.6, H 7.9, N 8.2%. IR: 2122 s, 1639 m, 1346
s, 1212 w, 1152 m, 1074 s, 1057 s, 989 m, 919
m, 1075 m, 1016 m, 974 w, 944 w, 914 w, 848
w, 777 s, 738 m, 702 s, 484 w, 418 w cmy
.
1
w
Ž
.
x
MS: mrz 203 C6H5C NC3H7 2, 25% , 161
w, 889 w, 843 w, 774 m, 702 w, 669 w, 533 w,
1
C H C N H N C H
1 2 % , 1 4 6
494 w, 439 w cmy . MS: mrz 686 M, 8% ,
w
w
Ž
.
,
7
x
w
x
6
5Ž
.
3x
w
Ž
.
w
Ž
.
x
10% , 283
C6H5C NC3H7 , 7% , 132 C6H5C NC2H5 ,
403 M-C 6 H 5C NC 6 H 11
,
2
x
w
x
w
w
Ž
.
,
2
x
17% , 104 C6H5CNH, 100% , 58 HNC3H7,
C H C N C H
1 0 0 % , 2 0 1
6
5
6
1 1

(
)
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
159
w
Ž
.
x
w
Ž
.
Ž
C6H5CNH NC6H11 , 22% , 104 C6H5CNH,
4.62 m, 2 H, C HC5H10 , 2.85 m, 2 H,
1
x
Ž
.
Ž
.
Ž
.
59% . H NMR THF-d8 : d 7.08–7.61 m, 10
C HC5H10 , 0.91–2.25 m, 40 H, CHC5 H10
ppm. 13C NMR THF-d8 :
d
155.2 s,
140.0
.
Ž
.
Ž
.
w
H, C6H5 3.02 m, 4 H, C HC5H10 , 0.85–2.15
Ž
.
Ž
Ž
.
Ž
.
Ž
x
w
m, 40 H, CHC5 H10 ppm.
C F3 3 C 6 H C N C 6 H 11
,
s,
2
2
2
.
x
CF3 3C6H2, Cipso , 135.5 q, p-C6H2, JC – F
X
2
(
3.5. Dichloro-bis N,N -dicyclohexylbenzami-
dinato zirconium IV
.
Ž
s32.4 Hz , 132.3 q, o-C6H2, JC – F s32.4
3
)
( ) ( )
4
.
Ž
.
Hz , 129.9 q, m-C6H2, JC – F s6.8 Hz , 123.7
1
Ž
.
Ž
.
q, CF3, JC – F s274.5 Hz , 58.8 s, CHC5H10 ,
Ž .
17.2 mmol
Ž .
Treatment of 6.49
g
Ž
.
Ž
.
Ž
54.0 s, CHC5H10 , 32.1 s, CHC5H10 , 26.3 s,
Ž
.
ZrCl4 THF
with 9.97 g 34.3 mmol of
CHC5H10 , 25.9 s, CHC5H10 ppm. 19F NMR
2
.
Ž
.
w
Ž
.
x
Ž
.
Li C6H5C NC6H11 2 affords 8.02 g 64% of
the pale yellow product, m.p. 1188C. Found: C
61.9, H 6.9, N 7.5; calcd. for C38H54Cl2 N4Zr
Ž
.
Ž
THF-d8, 235.32 MHz : d y57.5 Hz s, 12 F,
.
Ž
.
o-CF3 , y63.3 Hz s, 6 F, p-CF3 ppm.
X
Ž
.
(
)
729.01 : C 62.6, H 7.5, N 7.7%. IR: 3271 m,
3.7. Bis N,N -dicyclohexylbenzamidinato di-
methylzirconium IV
( ) ( )
2118 m, 1635 w, 1605 m, 1529 m, 1349 w,
6
1221 w, 1153 m, 1076 m, 991 w, 930 w, 891 w,
844 w, 776 m, 705 w, 670 w, 525 w, 491 w,
Ž
.
w
Ž
. x
3.0 g 4.1 mmol C6H5C NC6H11 2 2 ZrCl2
Ž .
4 is suspended in 50 ml of diethylether and
1
434 w cmy . MS: mrz 283 C6H5C NC6H11 2
,
w
Ž
.
Ž
.
0.27 g 12.4 mmol methyllithium in 40 ml
diethylether is added dropwise at y208C. The
mixture is stirred for another 15 min at y208C
and allowed to warm up to room temperature
overnight. The solvent is completely removed in
x
w
Ž
.
x
88% , 201 C6H5CNH NC6H11 , 84% , 121
C6H5C NH2 2, 55% , 104 C6H5CNH, 100% ,
98 HNC6H11, 48% . H NMR THF-d8 : d
w
Ž
.
x
x
w
x
1
w
Ž
.
Ž
.
Ž
7.08–7.61 m, 10 H, C6H5 , 2.80 m, 4 H,
.
Ž
.
C HC5H10 , 0.82–2.17 m, 40 H, CHC5 H10
Ž
vacuo, the residue is redissolved in pentane 30
ml and the resulting solution is filtered through
a thin layer of Celite filter aid in order to
remove insoluble particles. Evaporation of the
filtrate to dryness affords 1.67 g 59% of a
yellow crystalline solid, m.p. 1358C. Found: C
69.0, H 8.2, N 7.6; calc. for C40H60N4Zr
ppm. 13C NMR
CDCl3
:
d
177.8
Ž
.
.
w
Ž
.
x
Ž
.
C6H5C NC6H11 2 , 139.8 C6H5, Cipso , 132.0
C6H5 , 129.8 C6H5 , 128.9 C6H5 , 128.7
C6H5 , 126.1 C6H5 , 58.1 CHC5H10 , 34.6
Ž
Ž
Ž
.
Ž
.
Ž
.
.
Ž
.
Ž
.
Ž
.
.
Ž
.
Ž
.
CHC5H10 , 25.8 CHC5H10 , 24.7 CHC5H10
ppm.
X
Ž
.
688.17 : C 69.8, H 8.8, N 8.1%. IR: 3438 w,
[
3.6. Dichloro-bis N,N -dicyclohexyl-2,4,6-
3060 m, 1638 m, 1578 m, 1347 vs, 1311 s,
1212 m, 1153 s, 1100 s, 1074 s, 990 m, 953 m,
918 w, 889 w, 775 m, 702 m, 666 w, 633 w,
624 w, 490 w, 430 w cmy1. MS: mrz 283
(
)
]
tris trifluoromethyl benzamidinato zirconium
( ) ( )
IV
5
Ž
.
.
The reaction of 3.47
ZrCl4 THF
g
9.2 mmol
18.3 mmol
Ž
.
Ž
w
w
w
Ž
.
,
2
x
with 9.07
g
C H C N C H
1 0 0 % , 2 0 1
2
6
5
6
1 1
w
Ž
.
Ž
. x
Ž
.
x
Li CF3 3C6H2C NC6H11 2 affords 2.46 g
C H C N H N C H
,
w
9 1 % , 1 2 1
6
6
1 1
5Ž
.
x
x
Ž
Ž
.
.
24% of a cream-colored solid, m.p. 1618C
dec. . Found: C 45.9, H 4.0, N 4.3; calc. for
C44H48Cl2 F18N4Zr 1136.99 : C 46.5, H 4.3, N
4.9%. IR: 2122 w, 1652 m, 1605 w, 1583 w,
C6H5C NH2 2, 74% , 104 C6H5CNH, 90% ,
98 HNC6H11, 50% . 1H NMR C6D6 : d
w
x
Ž
.
Ž
.
Ž
.
Ž
7.00–7.25 m, 10 H, C6H5 , 3.30 m, 2 H,
CHC5H10 , 2.95 m, 2 H, CHC5H10 , 0.81–2.25
m, 40 H, CHC5H10 , 0.28 s, 6 H, CH3 ppm.
C NMR C6D6 : d 175.5 C6H5C NC6H11 2 ,
.
Ž
.
Ž
.
Ž
.
1411 m, 1301 m, 1281 m, 1204 m, 1152 s, 912
13
w, 891 w, 870 w, 685 w, 538 w, 465 w cmy
.
1
Ž
.
w
Ž
. x
w
Ž
.
Ž
.
x
Ž
.
Ž
.
MS: mrz 488 CF3 3C6H2C NC6H11 2, 10% ,
419
CF3 3C6H2C NH2 2, 71% , 83 C6H11, 12% .
H NMR THF-d8 : d 8.59 s, 4 H, C6H2 ,
137.7 C6H5, Cipso , 130.0 C6H5 , 126.6
w
.
Ž
. Ž . x
CF3 2C6 H2C NC6 H11 2, 10% , 325
Ž
Ž
Ž
.
Ž
.
Ž
.
.
C6H5 , 126.4 C6H5 , 57.0 CHC5H10 , 49.1
w
Ž
Ž
.
x
w
x
.
.
Ž
.
Ž
CH3 , 36.4 CHC5H10 , 27.2 CHC5H10 , 26.7
CHC5H10 ppm.
1
Ž
.
Ž
.

(
)
160
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
(
)
(
)
3.8. Reactions of C5 Me5 MCl3 MsTi, Zr
low crystals, m.p. 758C. Found: C 54.1, H 6.2,
[
(
)2 ]
Ž
.
w ith L i C 6 H 5 C N C 6 H 1 1
a n d
N 5.2; calc. for C23H34Cl2 N2 Zr 500.67 : C
[
(
) ] (
)
Li C6 H5C NC3 H7
general procedure
55.2, H 6.9, N 5.6%. IR: 1635 s, 1207 w, 974
2
1
m, 937 w, 919 w, 890 w, 674 m, 485 m cmy
.
To a solution of the given amount of
C5Me5 TiCl3 or C5Me5 ZrCl3 in 70 ml THF
w
Ž
.
x
MS: mrz 295 C5Me5 ZrCl2, 18% , 203
Ž
.
Ž
.
w
Ž
.
x
w
C6H5C NC3H7 2, 20% , 104 C6H5CNH,
1
is added dropwise at 08C the lithium benzamidi-
nate, dissolved in 30 ml THF. After warming to
room temperature the reaction mixture is stirred
for another 24 h. The solvent is completely
removed in vacuo, the residue is redissolved in
toluene 70 ml and filtered through a thin layer
of Celite. After evaporation of the filtrate to
dryness, the residue is washed with hexane and
x
Ž
.
100% . H NMR CDCl3, 200.13 MHz : d 7.60
m, 3 H, C6H5 , 7.30 m, 2 H, C6H5 , 3.20
sept, 2 H, C H CH3 2, JH – H s6.5 Hz , 2.07
s, 15 H, C5 CH3 5 , 1.19 d, 12 H, CH C H3 2
JH – H s6.5 Hz ppm. C NMR CDCl3 : d
164.0 C6H5C NC3H7 , 132.0 C6H5, Cipso
129.9 C5 CH3 5 , 127.9 C6H5 , 127.5 C6H5 ,
127.0 C6H5 , 126.4 C6H5 , 125.9 C6H5 ,
Ž
.
Ž
.
x
3
w
Ž
.
w
Ž
.
x
w
Ž
.
,
3
13
x
Ž
.
Ž
.
w
w
Ž
.
.
x
Ž
.
.
.
,
Ž
x
2Ž
.
Ž
Ž
Ž
w
.
Ž
.
Ž
.
dried under vacuum 12 h .
Ž
.
x
w
Ž
. x
48.2 CH CH3 2 , 23.1 CH CH3 2 , 13.3
w
Ž
. x
C5 CH3 5 ppm.
X
(
)
3.9. Dichloro- N,N -diisopropylbenzamidinato -
5
X
(
)
( )
h -pentamethylcyclopentadienyl titanium IV
(
3.11. Dichloro- N,N -dicyclohexylbenzami-
5
( )
7
) (
)
dinato - h - pentamethylcyclopentadienyl titan-
( ) ( )
ium IV
9
Ž
. Ž
.
From 0.87 g 3.0 mmol C5Me5 TiCl3 and
2 x
Ž
.
w
Ž
.
0.63 g 3.0 mmol Li C6H5C NC3H7
are
Ž .
3.0 mmol
3.0 mmol
Treatment of 0.87
g
Ž
.
isolated 0.38 g 28% of the orange product,
Ž
.
Ž
.
C5Me5 TiCl3 with 0.87
g
Ž
.
m.p. 1358C dec. . Found: C 59.3, H 7.0, N 5.6;
w
Ž
.
x
Ž
.
Li C6H5C NC6H11 2 affords 0.56 g 36% of
Ž
.
calc. for C23H34Cl2 N2Ti 457.33 : C 60.4, H
7.5, N 6.1%. IR: 1636 s, 1312 m, 1113 m, 702
m, 620 m, 452 m, 398 m cmy1. MS: mrz 457
Ž
.
an orange crystalline solid, m.p. 1598C dec. .
Found: C 63.8, H 7.1, N 4.7; calc. for
C29H42Cl2 N2Ti 537.46 : C 64.8, H 7.9, N
5.2%. IR: 1635 s, 1591 m, 1064 m, 978 w, 959
w, 892 w, 844 w, 772 s, 746 s, 665 w, 621 w,
Ž
.
w
w
x
w
Ž
. x
C5Me5 TiCl2, 8% , 203
M, 1% , 259
Ž
.
x
w
x
C6H5C NC3H7 2, 6% , 135 C5Me5, 100% ,
1
1
w
x
Ž
105 C6H5CNH2, 24% . H NMR THF-d8,
200.13 MHz : d 7.55 m, 5 H, C6H5 , 3.42
452 w, 397
w
.
cmy
.
MS: mrz 283
.
Ž
.
x
w
Ž
x
w
Ž
.
C6H5C NC6H11 2, 4% , 254 C5Me5 TiCl2,
3
w
Ž
.
sept, 2 H, C H CH3 2, JH – H s6.3 Hz , 2.27
x
w
w
x
w
x
6% , 135 C5Me5, 15% , 98 HNC6H11, 12% ,
83 C6H11, 28% . H NMR THF-d8, 200.13
1
w
Ž
.
x
w
Ž
.
,
s, 15 H, C5 CH3 5 , 1.35 d, 12 H, CH C H3 2
x
Ž
3
13
x
Ž
.
JH – H s6.3 Hz ppm. C NMR THF-d8 : d
.
Ž
.
Ž
. x
MHz : d 7.52 m, 5 H, C6H5 , 3.21 m, 2 H,
w
Ž
Ž
.
x
w
Ž
.
. x
162.1 C6H5C NC3H7 , 134.6 C5 CH3 5 ,
.
w
Ž
C HC5H10 , 2.21 s, 15 H, C5 CH3 5 , 0.82–
2
2.38 m, 20 H, CHC5 H10 ppm. 13C NMR
.
Ž
Ž
132.4 C6H5, Cipso , 130.7 C6H5 , 129.8
Ž
.
Ž
Ž
.
.
Ž
.
.
C6H5 , 129.0 C6H5 , 128.1 C6H5 , 127.9
Ž
Ž
.
w
Ž
. x
THF-d8 : d 158.5 C6H5C NC6H11 2 , 141.2
w
Ž
.
x
w
Ž
. x
C6H5 , 48.0 CH CH3 2 , 23.5 CH CH3 2 ,
.
w
Ž
.
.
x
Ž
.
C6H5, Cipso , 134.5 C5 CH3 5 , 130.4 C6H5 ,
w
Ž
. x
13.5 C5 CH3 5 ppm.
Ž
.
Ž
Ž
.
129.8 C6H5 , 129.6 C6H5 , 128.8 C6H5 ,
Ž
.
Ž
.
126.0 C6 H 5
CHC5H10 , 26.3 CHC5H10 , 23.4 CHC5H10 ,
13.4 C5 CH3 5 ppm.
,
55.6 C HC 5 H 10 ,
32.4
X
(
3.10. D ichloro- N,N -diisopropylbenz-
amidinato - h - pentamethylcyclopentadien-
( ) ( )
yl zirconium IV
Ž
.
Ž
.
Ž
.
5
) (
w
Ž
. x
)
8
3.12. Ethylene and propylene polymerizations
Ž
Ž
.
.
The reaction of 0.87
g
g
2.5 mmol
2.5 mmol
Ž .
Ž
.
C5Me5 ZrCl3 with 0.53
2 x
General procedure: A 100 ml glass reactor
with a strong magnetic stirrer, flame dried under
w
Ž
.
Li C6H5C NC3H7
yields 0.39 g 33% yel-

(
)
J. Richter et al.rJournal of Molecular Catalysis A: Chemical 130 1998 149–162
161
vacuum for few hours, was charged with 5 mg
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M. Wedler, F. Knosel, M. Noltemeyer, F.T. Edelmann, J.
¨
Ž
.
Organomet. Chem. 388 1990 21.
w x
Ž .
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F.T. Edelmann, Coord. Chem. Rev. 137 1994 403.
w x
Ž
.
3
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w x
4
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Ž
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Ž
.
Am. Chem. Soc. 115 1993 4931.
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5
D. Herscovics-Korine, M.S. Eisen, J. Organomet. Chem. 503
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Ž
.
1995 307.
˚
.
Davison 4 A molecular sieve column were
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Polymerizations were quenched by introducing
30 ml of methanolrHCl. Polyethylene was fil-
tered out washed with water, pentane and ace-
tone. For polypropylene, the organic layer was
separated and washed with water, treated with
molecular sieves and dried under vacuum 0.001
mm Hg at 608C for few hours.
w x
6
R. Gomez, R. Duchateau, A.N. Chernega, A. Meetsma, F.T.
´
Edelmann, J.H. Teuben, M.L.H. Green, J. Chem. Soc. Dalton
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.
Trans. 1995 217.
w x
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.
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J.R. Hagadorn, J. Arnold, Organometallics 13 1994 4670.
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.
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¨
Ž
.
Organomet. Chem. 508 1996 13.
w
w
w
w
x
10 D. Walther, R. Fischer, M. Friedrich, P. Gebhardt, H. Gorls,
¨
Ž
.
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x
Ž
.
11 A. Bino, F.A. Cotton, W. Kaim, Inorg. Chem. 18 1979
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x
For polypropylene, the 13C NMR shows only
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Ž
.
Trans. 1986 1359.
x
Ž
.
13 J. Barker, M. Kilner, J. Chem. Soc. Dalton Trans. 1987
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w
w
w
x
Ž
.
14 Y. Zhou, D.S. Richeson, Inorg. Chem. 35 1996 2448.
x
Ž
.
15 J.R. Hagadorn, J. Arnold, Inorg. Chem. 36 1997 132.
x
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¨
Ž
.
D. Amberger, Chem. Ber. 125 1992 2171.
w
w
w
w
w
x
Ž
.
17 F.A. Cotton, W.H. Ilsley, W. Kaim, Inorg. Chem. 13 1980
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x
18 S. Gambarotta, S. Stroloyo, C. Floriani, A. Chiesi-Villa, C.
Ž
.
Guastini, Inorg. Chem. 24 1985 654.
x
19 D. Fenske, E. Hartmann, K. Dehnicke, Z. Naturforsch. 43b
Ž
.
1988 1611.
The relevant signals for the determination
x
20 H.W. Roesky, B. Meller, M. Noltemeyer, H.-G. Schmidt, U.
Ž
.
Ž
.
Ž
.
are: d C6D8 135.7 A2 , 114.3 A1 , 46.2
Ž
.
Scholz, G.M. Sheldrick, Chem. Ber. 121 1988 1403.
x
21 K.-H. Thiele, H. Windisch, H. Windisch, F.T. Edelmann, U.
Ž
.
Ž
.
Ž
.
Ž
.
B4 , 24.5 B2 , 21.5 B3 , 20.5 B1 . No sig-
Ž
.
Kilimann, M. Noltemeyer, Z. Anorg. Allg. Chem. 622 1996
nals were observed at 142, 109.5 ppm from a
vinylidene end group or at 12.5 ppm for the
n-propyl group.
713.
w
w
w
w
w
w
w
w
x
22 J.-K. Buijink, M. Noltemeyer, F.T. Edelmann, Z. Natur-
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.
forsch. B 46 1991 1328.
x
23 M. Sotoodeh, I. Leichtweis, H.W. Roesky, M. Noltemeyer,
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.
H.-G. Schmidt, Chem. Ber. 126 1993 913.
x
24 C. Ergezinger, F. Weller, K. Dehnicke, Z. Naturforsch. B 43
Ž
.
1988 1119.
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x
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.
Organometallics 3 1984 977.
x
26 F.S. Dychachkovskij, A.K. Shilova, A.E. Shilov, J. Polym.
This research was supported by the Ministry
of Sciences and Arts, Ministry of Niedersach-
sen, Germany and the Technion, by the Israel
Science Foundation administered by the Israel
Academy of Sciences and Humanities under
Contract 76r94-1, and by the V.P.R. Fund Pro-
motion of Sponsored Research.
Ž
.
Sci. 16 1967 2333.
x
Ž
.
27 P.T. Wolczanski, J.E. Bercaw, Organometallics 1 1982
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x
Ž
.
28 R.P. Quirk Ed. , Transition Metal Catalyzed Polymeriza-
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Ž
.
29 W. Kaminsky, H. Sinn Eds. , Transition Metals and
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)
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30 J.A. Ewen, in: T. Keii, K. Soga Eds. , Catalytic Polymeriza-
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x
x
Ž
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.
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.
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.
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