Synthesis, structural features, and formation of organometallic derivates of C1-bridged Cp/amido titanium and zirconium CpCN-constrained geometry systems

Article abstract of DOI:10.1021/om0505918

A series of C₁-bridged Cp/amido group 4 metal complexes [( CpCN )MX₂] was prepared. The starting compound 6-tert-butylfulvene (7) was reacted with LiNHR (R = o-anisyl (a), p-anisyl (b), phenyl (c), or tert-butyl (d)) to yield the Li(C₅H ₄-CH(tBu)-NHR) compounds (8). Subsequent deprotonation with n-butyllithium, followed by transmetalation with Cl₂Ti(NMe ₂)₂, yielded the ( CpCN )Ti(NR₂) ₂ complexes 10 (a-d). A second synthetic series started from 6-(dimethylamino)fulvene (11). The reaction with the LiNHR reagents led to addition followed by HNMe₂ elimination to yield the respective imino-substituted cyclopen-tadienides Li(C₅H₄-CH=NR) (13). Addition of methyllithium to 13 gave the (Li⁺)₂(C ₅H₄-CHMe-NR)^2-, ( CpCN ) ^2-, ligands (14). Transmetalation with Cl₂Ti(NMe ₂)₂ subsequently yielded the corresponding μ-CHMe-bridged Cp/amido group 4 complexes 15 (a-c). Treatment with Me ₂SiCl₂ cleanly converted the ( CpCN )M(NR ₂)₂ complexes to the respective ( CpCN )MCl ₂ systems [3a-d, 4a-c (Ti), 5a (Zr)]. These were transformed to the ( CpCN )M(CH₃)₂ complexes [μ-CHCMe ₃: 17a-d (Ti), 19a (Zr), μ-CHMe: 18a-c (Ti)] and the (s-cis-supine-η⁴-butadiene)( CpCN )Ti systems 21a-d and 22b,c. With respect to X-ray structure analyses the (CpCN)MX₂ systems must be regarded as more constrained than their ( CpSiN )MX₂ analogues. The ( CpCN )MCl ₂ and ( CpCN )M(CH₃)₂ complexes were used as catalysts for ethene homopolymerization and ethene/1-octene copolymerization. All systems gave active catalysts, but these were quite different in their catalytic performance when compared with the usually applied ( CpSiN )TiX₂-derived catalysts. The ( CpCN )M catalyst activities and selectivities were very dependent on the specific activator components employed.

Full text of DOI:10.1021/om0505918

4760
Organometallics 2005, 24, 4760-4773
Synthesis, Structural Features, and Formation of
Organometallic Derivates of C1-Bridged Cp/Amido
Titanium and Zirconium “CpCN-Constrained Geometry”
Systems
Cun Wang, Gerhard Erker,* Gerald Kehr, Katrin Wedeking,# and
Roland Fro¨hlich#
Organisch-Chemisches Institut der Universita¨t Mu¨nster, Corrensstrasse 40,
48149 Mu¨nster, Germany
Received July 13, 2005
A series of C1-bridged Cp/amido group 4 metal complexes [(“CpCN”)MX2] was prepared.
The starting compound 6-tert-butylfulvene (7) was reacted with LiNHR (R ) o-anisyl (a),
p-anisyl (b), phenyl (c), or tert-butyl (d)) to yield the Li(C5H4-CH(tBu)-NHR) compounds
(8). Subsequent deprotonation with n-butyllithium, followed by transmetalation with Cl2-
Ti(NMe2)2, yielded the (“CpCN”)Ti(NR2)2 complexes 10 (a-d). A second synthetic series
started from 6-(dimethylamino)fulvene (11). The reaction with the LiNHR reagents led to
addition followed by HNMe2 elimination to yield the respective imino-substituted cyclopen-
tadienides Li(C5H4-CHdNR) (13). Addition of methyllithium to 13 gave the (Li+)2(C5H4-
CHMe-NR)2-, (“CpCN”)2-, ligands (14). Transmetalation with Cl2Ti(NMe2)2 subsequently
yielded the corresponding µ-CHMe-bridged Cp/amido group 4 complexes 15 (a-c). Treatment
with Me2SiCl2 cleanly converted the (“CpCN”)M(NR2)2 complexes to the respective (“CpCN”)-
MCl2 systems [3a-d, 4a-c (Ti), 5a (Zr)]. These were transformed to the (“CpCN”)M(CH3)2
complexes [µ-CHCMe3: 17a-d (Ti), 19a (Zr), µ-CHMe: 18a-c (Ti)] and the (s-cis-supine-
η4-butadiene)(“CpCN”)Ti systems 21a-d and 22b,c. With respect to X-ray structure analyses
the (CpCN)MX2 systems must be regarded as more “constrained” than their (“CpSiN”)MX2
analogues. The (“CpCN”)MCl2 and (“CpCN”)M(CH3)2 complexes were used as catalysts for
ethene homopolymerization and ethene/1-octene copolymerization. All systems gave active
catalysts, but these were quite different in their catalytic performance when compared with
the usually applied (“CpSiN”)TiX2-derived catalysts. The (“CpCN”)M catalyst activities and
selectivities were very dependent on the specific activator components employed.
Introduction
merization catalysts.3 Many variations were carried out
at the original framework, especially with regard to
variations at the Cp ring and the substituents at the
bridging silicon and the nitrogen center.4,5 Okuda and
others have described a great variety of (CpSiN)MX2
derivates that contain an additional donor group that
The silicon-bridged Cp/amido framework of the “con-
strained geometry” metal complexes was introduced by
Bercaw et al. originally in scandium chemistry1 and
shortly thereafter applied by several groups for the
preparation of the respective group 4 metal complexes.2
The silicon-bridged “CpSiN” group 4 metal systems (1)
have found significant use in homogeneous Ziegler-
Natta catalysis, especially the titanium systems, which
were shown to give excellent ethene/1-alkene copoly-
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10.1021/om0505918 CCC: $30.25 © 2005 American Chemical Society
Publication on Web 08/23/2005

C1-Bridged Cp/Amido Titanium and Zirconium Systems
Organometallics, Vol. 24, No. 20, 2005 4761
Scheme 1
was attached directly or by a suitable linker at the
amido nitrogen atom.6
There are much fewer reports about related systems
where either the bridging group 14 or the terminal
anionic group 15 element has been varied. The “Cp-
SiP”ZrCl2 system has been reported,7 and synthetic
entries to the related “CpCN” and “CpCP” group 4 metal
complexes were developed.8-10 “CpCN” compounds should
in principle be more “constrained” than “CpSiN” and,
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consequently, show different catalytic behavior. This
was observed, but due to the limited number of ex-
amples of these types of complexes not well understood.
We here describe the synthesis and structural charac-
terization of a larger series of “CpCN”TiX2 and “CpC-
N”ZrX2 complexes and of some organometallic deriva-
tives that were used to arrive at a better understanding
of the chemical and catalytic properties of this interest-
ing class of compounds.8
Results and Discussion
Synthesis of the “CpCN” Group 4 Metal Com-
pounds. In this study two reaction routes to “CpCN”
ligand systems were used that had previously been
developed and described by us.8,11 Both are derived from
suitably substituted fulvenes as starting materials.
6-tert-Butylfulvene (7) was shown to add a variety of
lithium amide reagents LiNHR at the electrophilic
fulvene carbon atom C6 to yield the respective -CH-
(CMe3)-NHR-substituted cyclopentadienides (8). For
this study, these were not isolated, but depronotated
in situ at the secondary amine nitrogen by the subse-
quent addition of n-butyllithium to yield the “CpCN”
dianion equivalents (9). The dilithio reagents (9) were
isolated and characterized by NMR spectroscopy. Since
it was known that the reaction of some reagents 9 with
TiCl4 or ZrCl4 led to the organometallic “spiro” com-
plexes of the composition (“CpCN”)2M,8 transmetalation
was carried out with the TiCl2(NMe2)2 reagent12 to asure
a clean reaction in a 1:1 ratio to yield the respective
(“CpCN”)Ti(NMe2)2 products (10). These complexes8
1
were characterized by H NMR spectroscopy and then
directly treated with Me2SiCl2 9 to yield the correspond-
ing (“CpCN”)TiCl2 products 3a-d (see Scheme 2).
Both the p-anisyl (3b) and the o-anisyl substituted
complex (3a) feature very similar sets of 1H NMR
signals of diastereotype pairs of C5H4 hydrogens (3b:
δ 6.29, 6.26, 6.23, 5.91), although two of the methine
signals of the latter are shifted to larger δ-values (3a:
δ 6.75, 6.62, 6.25, 5.70). The 13C NMR resonance of the
bridging carbon atom C6 of 3b occurs at δ 70.5, of 3a at
δ 68.5. A major difference is observed between the
-OCH3 1H NMR and 13C NMR resonances [(3b: δ 3.23-
(1H), δ 54.9(13C); 3a: δ 4.35(1H), 59.4(13C)]. This marked
(7) Koch, T.; Hey-Hawkins, E. Polyhedron 1999, 18, 2113-2116.
Koch, T.; Blaurock, S.; Somoza, F. B.; Voigt, A.; Kirmse, R.; Hey-
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Z.; Nishiura, M.; Koizumi, T.; Wakatsuki, Y. Organometallics 2001,
20, 4565-4573. Altenhoff, G.; Bredeau, S.; Erker, G.; Kehr, G.;
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also: Stevens, J. C.; Timmers, F. J.; Wilson, D. R.; Schmidt, G. F.;
Nickias, P. N.; Rosen, R. K.; Knight, G. W.; Lai, S. (Dow) Eur. Pat.
Appl. 0 416 815 A2, 1991.
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R.; Zippel, F. Eur. J. Inorg. Chem. 1998, 1153-1162. Kunz, D.; Erker,
G.; Fro¨hlich, R.; Kehr, G. Eur. J. Inorg. Chem. 2000, 409-416. Kunz,
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2001, 123, 6181-6182. Kunz, K.; Erker, G.; Do¨ring, S.; Bredeau, S.;
Kehr, G.; Fro¨hlich, R. Organometallics 2002, 21, 1031-1041.
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Eur. J. Inorg. Chem. 2004, 1522-2529.
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Heidemann, T.; Jutzi, P. Synthesis 1994, 777-778. Koch, T.; Hey-
Hawkins, E. Polyhedron 1999, 18, 2113-2116. Koch, T.; Blaurock, S.;
Somoza, F. B., Jr.; Voigt, A.; Kirmse, R.; Hey-Hawkins, E. Organome-
tallics 2000, 19, 2556-2563. Bildmann, U. J.; Mu¨ller, G. Z. Naturfor-
sch. 2000, 55, 895-900. Ho¨cher, T.; Blaurock, S.; Hey-Hawkins, E. Eur.
J. Inorg. Chem. 2002, 1174-1180. Ishiyama, T.; Mizuta, T.; Miyoshi,
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2001, 20, 392-400, and references therein.
(12) Benzing, E.; Kornicker, W. Chem. Ber. 1961, 94, 2263-2267.

4762 Organometallics, Vol. 24, No. 20, 2005
Wang et al.
Scheme 2
Scheme 4
Scheme 5
Scheme 3
downfield shift is probably caused by the internal
coordination of the oxygen atom of the methoxy group
to the titanium center, as will later be supported by the
X-ray crystal structure analysis (see below).
(“CpCN”)TiCl2 complexes 3 and 4 were reacted with
methylmagnesium chloride to give the corresponding
(“CpCN”)Ti(CH3)2 complexes (17a-d and 18a-c) in
yields ranging from 64% to 81%. Some of the complexes
were isolated as yellow to red oils, others as yellow
solids. Several of the compounds were characterized by
X-ray diffraction. The (“CpCN”)ZrCl2 complex 5a showed
a very low solubility once it was isolated as a solid. Its
reaction with the methyl Grignard reagent produced the
soluble (“CpCN”)Zr(CH3)2 product (19a), that was iso-
lated as a yellowish solid in >80% yield (Scheme 5).
The (“CpCN”)TiMe2 complex 18a features a pair of
Ti-CH3 1H NMR signals at δ 0.29 and 0.11. The -OCH3
1H NMR resonance was found at δ 4.00, which is
markedly shifted “downfield” as compared to its p-anisyl
isomer 18b (OCH3: δ 3.37), which indicated coordina-
tion of the substituent oxygen atom to titanium. This
was further supported by an NOE experiment: irradia-
tion at the 1H NMR -OCH3 resonance produced a
strong response at both [Ti](CH3)2 signals in complex
18a. The structurally related o-anisyl-substituted tita-
nium system 17a features a -OCH3 1H NMR resonance
at δ 4.03 and [Ti](CH3)2 1H NMR signals at δ 0.46 and
0.03. The zirconium analogue of 18a, the (“CpCN”)Zr-
(CH3)2 complex 19a, shows a pair of [Zr](CH3)2 1H NMR
resonances at markedly lower δ values (δ 0.09 and
-0.30) and a -OCH3 1H NMR signal at δ 3.81. All these
systems showed NOE spectra that indicated coordina-
tion of the o-anisyl methoxide oxygen atom to the group
4 metal center.
A second series of (“CpCN”) titanium and zirconium
complexes was prepared that featured a methyl sub-
stituent at the bridging carbon atom (C6). The synthesis
of these systems required a different route, since the
reaction of a strongly basic LiNHR reagent with, for
example, 6-methylfulvene would have resulted in depro-
tonation at the methyl substituent to form an alkenyl-
cyclopentadienide.12 Therefore 6-(dimethylamino)ful-
vene (11)13 was reacted with the LiNHR reagents to
yield the aldimino-substituted cyclopentadienides (13)
by means of an amide addition/dimethylamine elimina-
tion process.11 Addition of methyllithium to 13 gave the
respective “CpCN” dianion equivalents (14), which were
subsequently transmetalated by treatment with the
TiCl2(NMe2)2 reagent to yield the (“CpCN”)Ti(NMe2)2
systems (15). Their treatment with Me2SiCl2 eventually
furnished the corresponding (“CpCN”)TiCl2 products
(4a-c) (see Scheme 3).
The [(“CpCN”)2-](Li+)2 reagent 9a was also reacted
14
with ZrCl2(NMe2)2(THF)2 to give the corresponding
(“CpCN”)Zr(NMe2)2 product (16a). Again, the reaction
with Me2SiCl2 was used to exchange the dialkylamido
σ-ligands at the group 4 transition metal center for
chlorides. The (“CpCN”)ZrCl2 product (5a, see Scheme
4) was isolated as a pale yellow solid in ca. 80% yield.
Formation of Organometallic Derivates of the
(“CpCN”)Titanium and Zirconium Complexes. The
(13) Hafner, K.; Schulz, G.; Wagner, K. Liebigs Ann. Chem. 1964,
678, 39-53. See also: Hafner, K.; Vo¨pel, K. H.; Ploss, G.; Ko¨nig, C.
Org. Synth. 1967, 47, 52-54.

C1-Bridged Cp/Amido Titanium and Zirconium Systems
Organometallics, Vol. 24, No. 20, 2005 4763
Scheme 6
Group 4 metal dihalide complexes react readily with
the “butadiene-magnesium” reagent15 to yield the cor-
responding (η4-butadiene)metal complexes. It had been
shown that the conventional (“CpSiN”)TiCl2 and -ZrCl2
systems (1) furnished mixtures of “prone”- and “supine”
-η4-butadiene metal complex isomers upon treatment
with the butadiene-dianion equivalent (see Scheme 6).
The equilibrium ratios of these isomers were dependent
on the substituent pattern of the ligand framework and
the metal. There was a tendency that the “prone”
structures were favored for the Ti complexes and the
“supine” structures for zirconium in many (“CpSiN”)M-
(butadiene) examples.16,17,21 This was different in the
(“CpCN”)Ti(butadiene) series.
Figure 1. Dynamic 1H NMR spectra (600 MHz, d8-
toluene) of the aromatic region of complex 21b, indicating
a hindered rotation around the N-aryl vector.
Scheme 7
The (“CpCN”)TiCl2 complexes 3a-d, 4b, and 4c were
each reacted with the “butadiene-magnesium” reagent
to give the respective (η4-butadiene)titanium complexes
(21a-d, 22b, 22c). In each case the C4H6 ligand was
found to be coordinated in an s-cis-conformation,16,17 and
in each case only a single isomer was observed. In the
case of complex 21b (R ) p-anisyl) a low-temperature
1H NMR study revealed that no rapid isomerism
between prone and supine isomers18 obscured the
analysis.19 In toluene-d8 only a single set of signals was
observed down to the lowest temperature studied (193
K, 600 MHz). However, in this specific case it was
observed that the rotation around the N-(p-anisyl)
1
Table 1. Comparison of the Butadiene Ligand H
and 13C NMR Resonances of the
(“CpCN”)Ti(butadiene) Complexes 21 and 22 with
Some of Their (“CpSiN”)Ti(C4H6) Counterpartsa
d
d
d
e
d
compd δ 1Hmeso δ 1Hsyn δ 1Hanti ∆δH δ 13CHd δ 13CH2
21ac
21bb
21c
5.76
4.95
6.29
5.15
6.16
4.98
5.88
6.31
6.20
5.37
6.34
5.44
6.33
3.29
3.05
3.67
3.24
3.57
3.13
3.20
3.67
3.48
3.11
3.58
3.12
2.84
0.51 5.25 124.0
0.36 4.59 126.4
0.43 5.86 124.1
-0.07 5.22 124.9
0.47 5.69 125.1
-0.03 5.01 125.1
0.28 5.60 116.6
-0.20 6.51 129.9
0.32 5.88 124.8
0.07 5.30 124.8
0.35 5.99 125.7
0.13 5.31 125.4
0.04 6.29
63.6
64.2
63.3
65.7
64.2
66.4
64.2
66.2
64.0
65.2
65.6
66.6
21d
22bc
22c
1
vector became “frozen” on the H NMR time scale at
low temperature,20 which gave rise to a decoalescence
of the pair of -C6H4OCH3 1H NMR resonances below
Tc ) 233 K to four separate aromatic hydrogen reso-
nances (see Figure 1 and the Experimental Section for
details). From the temperature-dependent 1H NMR
spectra an N-aryl rotational barrier of ∆Gq(233 K) )
11.6 ( 0.3 kcal mol-1 was calculated.
20a f
(supine)
20a f
4.15
4.20
3.01
3.28
1.71 2.44 111.9
1.82 2.38 107.2
62.0
62.8
(prone)
20b f
(prone)
(14) Kempe, R. K.; Brenner, S.; Arndt, P. Z. Anorg. Allg. Chem. 1995,
621, 2021-2024.
(15) Fujita, K.; Ohnuma, Y.; Yasuda, H.; Tani, H. J. Organomet.
Chem. 1976, 113, 201-213. Yasuda, H.; Kajihara, Y.; Mashima, K.;
Nagasuna, K.; Lee, K.; Nakamura, A. Organometallics 1982, 1, 388-
396.
a Spectra in benzene-d6. b In toluene-d8 at 193 K. c In toluene-
d8 at 298 K. d Each was separated into two values because of the
chiral carbon of the bridge in these butadiene complexes. e δ 1Hmeso
1
- δ Hanti
.
f From ref 17.
(16) Reviews: Erker, G.; Kru¨ger, C.; Mu¨ller, G. Adv. Organomet.
Chem. 1985, 24, 1-39. Yasuda, H.; Tatsumi, K.; Nakamura, A. Acc.
Chem. Res. 1985, 18, 120-126. Erker, G.; Kehr, G.; Fro¨hlich, R. Adv.
Organomet. Chem. 2004, 51, 109-162.
(17) Dahlmann, M.; Schottek, J.; Fro¨hlich, R.; Kunz, D.; Nissinen,
M.; Erker, G.; Fink, G.; Kleinschmidt, R. J. Chem. Soc., Dalton Trans.
2000, 1881-1886. Strauch, J. W.; Petersen, J. L. Organometallics 2001,
20, 2623-2630.
(18) For the “prone” and “supine” definition see: Yasuda, H.;
Tatsumi, K.; Okamoto, T.; Mashima, K.; Lee, K.; Nakamura, A.; Kai,
Y.; Kanehisa, N.; Kasai, N. J. A. Chem. Soc. 1985, 107, 2410-2422.
(19) Erker, G.; Engel, K.; Kru¨ger, C.; Chiang, A.-P. Chem. Ber. 1982,
115, 3311-3323. Bu¨rgi, T.; Berke, H.; Wingbermu¨hle, D.; Psiorz, C.;
Noe, R.; Fox, T.; Knickmeier, M.; Berlekamp, M.; Fro¨hlich, R.; Erker,
G. J. Organomet. Chem. 1995, 497, 149-159.
Because of the presence of the chiral carbon center
in the C1-bridge, all the complexes 21 and 22 exhibit a
set of four separate C5H4 1H NMR signals and a total
of six butadiene 1H NMR resonances and four 13C NMR
resonances. The three pairs of C4H6 1H NMR signals
are widely separated and occur in characteristic regions
[e.g., 21d: δ 5.88/6.31 (Hmeso), δ 3.20/3.67 (Hsyn), 0.28/-
0.20 (Hanti)]. It was previously shown that the chemical
shift difference ∆δ of the 1H NMR Hmeso and Hanti
resonances was very different for the prone and supine
isomers [e.g., 20a: ∆δ (prone) ) 2.44, ∆δ (supine) ) 6.29
(see Scheme 7 and Table 1)].17,21 This can be used for a
spectroscopic identification of the isomer types. In the
case of the complexes 21 and 22 all our examples show
(20) Dreier, T.; Bergander, K.; Wegelius, E.; Fro¨hlich, R.; Erker, G.
Organometallics 2001, 20, 5067-5075.
(21) Devore, D. D.; Timmers, F. J.; Hasha, D. L.; Rosen, R. K.;
Marks, T. J.; Deck, P. A.; Stern, C. L. Organometallics 1995, 14, 3132-
3134.

4764 Organometallics, Vol. 24, No. 20, 2005
Wang et al.
structure determinations and the structural features of
all 10 compounds of this study are provided with the
Supporting Information. Some of the general structural
characteristics of this class of (“CpCN”)MX2 complexes
are discussed below by using selected examples.
Complex 3b may serve as an example to outline the
general characteristics of this class of compounds. The
central titanium atom in 3b is pseudotetrahedrally
coordinated to a pair of chloride ligands (Ti-Cl1 2.2697-
(5)/2.2717(5) Å, Ti-Cl2 2.2691(5)/2.2726(6) Å), the
amido nitrogen, and the Cp ligand of the CpCN ligand
system. The Ti-N1 bond is rather short (1.921(1)/1.919-
(1) Å).22 The Cp ligand is η5-coordinated to titanium,
but rather unsymmetrically probably because of the
strain imposed on the system by the short C1-bridge.
The Ti-C1 linkage is markedly shorter than the Ti-
C2/C5 bonds, which in turn are themselves slightly
shorter than the Ti-C3/C4 linkage (for values see Table
2). The connecting C1-C6 vector between the Cp ring
and the C1 bridge is bent out of the Cp ligand plane
toward the metal center. The corresponding Cp(cen-
troid)-C1-C6 angle amounts to 153.3°/153.1°. The
endocyclic C1-C6-N1 bond angle is 95.4° (averaged
value from two independent molecules), which is far
away from the tetrahedral sp3-C value. The “constrained
geometry” character in a series of related compounds
is probably best characterized by the Cp(centroid)-
metal-nitrogen angle, which responds sensitively to
steric and electronic geometry changes. In 3b it amounts
to 96.0°. The coordination geometry of the ligand
nitrogen atom is trigonal-planar. The p-anisyl substitu-
ent is rotated out of the plane of the nitrogen substit-
uents in a direction that minimizes its steric interaction
with the bulky tert-butyl group at C6 (dihedral angles:
C1-C6-N1-C8 168.8(1)°/-164.9(1)°, C6-N1-C8-C9
143.6(2)°/-144.0(1)°, Ti-N1-C8-C9 -53.0(2)°/66.2-
(2)°).
The o-anisyl-substituted -CH(CMe3)-bridged (“CpCN”)-
TiCl2 complex analogue 3a features a similar structure,
in which, however, the anisyl oxygen atom is coordi-
nated to titanium at a position trans to the unsym-
metrically bound η5-Cp ligand. The overall structure
may, therefore, be regarded as strongly distorted trigo-
nal-bipyramidal. The Cp(centroid)-Ti-O angle in 3a
amounts to 164.9°. The three basal angles at titanium
are 114.72(4)° (N-Ti-Cl1), 118.52(4)° (N-Ti-Cl2), and
111.25(2)° (Cl1-Ti-Cl2) [see for a comparison in 3b:
105.94(4)°/110.26(4)° (N-Ti-Cl1), 108.27(4)°/103.22(4)°
(N-Ti-Cl2), 104.51(2)°/106.76(2)° (Cl1-Ti-Cl2)]. The
Ti-O bond length (2.282(1) Å) is in the typical range
found in other ether adducts to CpTiX3 ,23 and the Ti-
Cl bond lengths amount to 2.329(1) Å (Ti-Cl1) and
2.331(1) Å (Ti-Cl2), respectively, which is markedly
larger than in 3b. Again, the C1-C6 vector is oriented
out of the Cp plane [Cp(centroid)-C1-C6: 156.5°,
which is ca. 3° more bent than in the otherwise related
complex 3b]. The C1-C6-N angle in 3a is 94.0(1)° and
the Cp(centroid)-Ti-N angle amounts to 93.6°, i.e.,
even slightly smaller than found in 3b. In contrast, the
Figure 2. 1H NMR and 1D-NOE spectra of complex 21d
(in benzene-d6).
Figure 3. Views of the (“CpCN”)TiCl2 complexes 3b (left)
and 3a (right) featuring p- and o-anisyl substituents at the
ligand nitrogen atom.
very large ∆δ (Hmeso - Hanti) values (in a range between
4.59 and 6.51 ppm), which indicates that in contrast to
the related (“CpSiN”)Ti(butadiene) systems17,21 the
newly prepared (“CpCN”)Ti(C4H6) examples (21, 22) all
favored a supine structure having the Hmeso hydrogen
atoms pointing away from the Cp ring.
The structural assignment of the (“CpCN”)Ti(buta-
diene) complexes 21 and 22 as “supine” isomers was
further supported by an NOE response of the Hmeso 1H
NMR pair of resonances (and the adjacent CH[C(CH3)3]
signals as well) upon irradiating the N-C(CH3)3 signal
of complex 21d (see Figure 2). Similar NOE features
were also observed for the other members of this series
of complexes.
The -OCH3 group of the o-anisyl substituent of the
(“CpCN”)Ti(butadiene) complex 21a seems not to be
coordinated to the titanium center in contrast to its
(“CpCN”)TiCl2 (3a) and (“CpCN”)TiMe2 (17a) relatives.
This was concluded from the observation of an “unper-
turbed” -OCH3 1H NMR resonance of 21a at δ 3.07
(3a: 4.35, 17a: 4.03).
X-ray Crystal Structure Analyses. Ten of the
(“CpCN”)M(IV) complexes prepared in the course of this
study were characterized by X-ray diffraction, among
them the µ-CH(CMe3)-bridged titanium dichlorides 3a,
3b, and 3d and the corresponding [Ti]Me2 system 17a.
In the µ-CH(CH3)-bridged Cp/amido series the titanium
dichlorides 4a, 4b, and 4c as well as their [Ti]Me2
derivates 18a and 18b were characterized by X-ray
crystal structure analyses. In addition, the structure of
the (“CpCN”)zirconium dimethyl system 19a was de-
termined. A comparison of some general structural
features is given in Table 2 together with some data of
the (“CpSiN”)TiX2 systems. Detailed information on the
(22) Erker, G.; Fro¨mberg, W.; Atwood, J. L.; Hunter, W. E. Angew.
Chem. 1984, 96, 72-73; Angew. Chem., Int. Ed. Engl. 1984, 23, 68-
69. Erker, G.; Fro¨mberg, W.; Kru¨ger, C.; Raabe, E. J. Am. Chem. Soc.
1988, 110, 2400-2405.
(23) Erker, G. J. Organomet. Chem. 1990, 400, 185-203, and
references therein.

C1-Bridged Cp/Amido Titanium and Zirconium Systems
Organometallics, Vol. 24, No. 20, 2005 4765
Table 2. Compilation of Characteristic Structural Parameters of the (“CpCN”)MX2 Complexesa
3d (Ti)b
4c (Ti)
3b (Ti)b
4b (Ti)
18b (Ti)
3a (Ti)
17a (Ti)b
4a (Ti)
18a (Ti)
19a (Zr)
M-C1
2.234(5)
2.242(5)
2.278(5)
2.275(6)
2.313(5)
2.323(6)
2.376(5)
2.364(6)
2.381(5)
2.391(6)
1.982
2.251(2)
2.258(2)
2.254(2)
2.311(2)
2.280(2)
2.303(2)
2.326(2)
2.374(2)
2.358(2)
2.366(2)
2.374(2)
1.987
2.259(2)
2.257(2)
2.278(1)
2.294(2)
2.298(2)
2.323(2)
2.331(2)
2.346(2)
2.346(2)
2.427(2)
2.424(2)
2.448(2)
2.438(2)
2.042
2.290(2)
2.312(2)
2.427(2)
M-C2
2.310(2)
2.302(2)
2.375(2)
2.372(2)
1.988
2.310(2)
2.312(2)
2.371(2)
2.370(2)
1.991
2.332(3)
2.311(3)
2.412(3)
2.412(3)
2.018
2.318(2)
2.331(2)
2.416(2)
2.432(2)
2.027
2.334(2)
2.326(2)
2.422(2)
2.422(2)
2.032
2.347(2)
2.353(2)
2.433(2)
2.445(2)
2.054
2.469(2)
2.484(2)
2.559(2)
2.576(2)
2.196
M-C5
M-C3
M-C4
Cp(centr.)-M
M-N
1.990
1.984
2.042
1.936(4)
1.930(4)
155.5
1.942(1)
154.0
1.921(1)
1.919(1)
153.3
1.933(1)
153.7
1.944(2)
153.8
1.963(1)
156.5
2.009(2)
2.005(2)
155.7
1.956(2)
155.8
1.989(1)
155.1
2.130(1)
158.0
Cp(centr.)-C1-C6
N-M-Cp(centr.)
C1-C6-N
M-O
154.6
153.1
155.4
96.3
96.2
96.1
96.0
97.4
93.6
94.2
93.4
93.3
89.4
96.8
95.9
93.9
94.7(4)
95.5(4)
96.8(1)
95.6(1)
95.1(1)
96.4(1)
98.5(2)
94.0(1)
2.282(1)
357.6
96.7(2)
96.3(2)
2.320(2)
2.302(2)
349.4
94.8(2)
2.295(2)
360.0
96.5(1)
2.332(1)
358.7
98.2(1)
2.320(1)
353.0
∑ N angles
∑ O angles
356.3
358.4
359.0
358.3
354.2
359.0
359.5
348.7
356.7
355.0
359.5
359.2
357.8
354.2
a Bond lengths in Å, angles in deg. b Values from two independent molecules in the unit cell.
4° smaller than the corresponding angle in the tetra-
coordinated isomer 18b (see Table 2). The zirconium
complex 19a also features a disturbed tetrahedral
coordination geometry of the central complex core that
is complemented by a weaker fifth donor coordination
of the o-anisyl ether oxygen. Again, the metal-oxygen
linkage is rather long (2.320(1) Å). The C5H4 unit of the
“CpCN” ligand features the typical slightly disturbed
η5-coordination with an elongated M-Cp(centroid) value
of 2.196 Å. The C1-C6 vector is oriented even more out
of the Cp plane [Cp(centroid)-Zr-C6: 158.0°], and the
Cp(centroid)-Zr-N angle in 19a amounts to only 89.4°
(see Table 3 and Figure 5).
The Cp(centroid)-metal-nitrogen angle serves as a
good qualitative measure to assess and compare the
structural “constraints” featured by the respective Cp/
amido ligand frameworks in the series of “CpCN”MX2
complexes and their various differently bridged coun-
terparts that were previously published in the litera-
ture. The open, nonbridged reference system 25 (see
Scheme 8) may mark the extreme, featuring a rather
large Cp(centroid)-Ti-N angle of 116.2°. Most of the
Me2Si-bridged titanium complexes (1) exhibit Cp(cen-
troid)-Ti-N angles around 105° to 107°, similar to the
-C2H4-bridged complex 24 (104°). All the four-coordi-
nate C1-bridged “CpCN” titanium complexes feature far
more “constrained” frameworks, featuring Cp(centroid)-
Ti-N angles between 97.4° and 95.9°. The correspond-
ing five-coordinate C1-bridged systems that contain a
weak internal ether oxygen donor binding to the metal
show even slightly smaller Cp(centroid)-Ti-N angles
in a range between 93.3° and 94.2° (see Table 2). We
must assume that the introduction of the one-carbon
µ-CHR bridge between the Cp and the amido unit in
the “CpCN” ligand frameworks results in an increase
of the steric constraints of the dianionic ligand systems
and an increased exposure of the central metal atom to
other incoming ligands. This effect becomes even more
pronounced on going to the related “CpCN”ZrX2 sys-
Figure 4. Molecular structures of the p-/o-anisyl-substi-
tuted (“CpCN”)TiMe2 complexes 18b (left) and 18a (right).
Ti-N bond length in the “pentacoordinated” complex
3a is 1.964(1) Å, which is >0.04 Å longer than the
corresponding bond in 3b. The chelating oxygen forces
the phenylene moiety in an orientation closer to the
CpCN ligand plane (θC1-C6-N-C8 159.9(1)°, Ti-N-
C8-C13-21.4(2)°).
The pairs of the corresponding CH(CH3)-bridged p-
and o-anisyl-substituted “CpCN”TiCl2 complexes (4b,
4a) show similar structural features (for details see
Table 2 and the Supporting Information). Figure 4
shows views of the molecular structures of the corre-
sponding pair of p-/o-anisyl-substituted (“CpCN”)TiMe2
complexes 18b and 18a.
In the dimethyl-Ti complexes 18 the Ti-C(Cp) bonds
seem to be slightly longer than in the respective [Ti]Cl2
complexes. Aside from that, very similar characteristic
differences in the essential bonding features are ob-
served between the examples of this pair of “constrained
geometry” complexes. In the chelate complex 18a the
Ti-N bond is >0.04 Å longer than in 18b (see Table 2),
which is probably caused by the competing oxygen
coordination. Also the Ti-CH3 σ-bonds in 18b [2.090-
(3) Å (Ti-C16), 2.092(3) Å (Ti-C15)] are shorter than
in 18a [2.130(2) Å (Ti-C16), 2.140(2) Å (Ti-C15)].
Again, the central CpCN framework seems to be more
“constrained” in the five-coordinate system 18a, which
features a Cp(centroid)-Ti-N angle (93.3°) that is ca.

4766 Organometallics, Vol. 24, No. 20, 2005
Wang et al.
Table 3. Ethene Polymerization Examples
Employing the (“CpCN”)MCl2 and (“CpCN”)MMe2
Complexes with Different Activatorsa
entry compd activator T (°C) t (min) g(PE) activityb
substantial structural changes introduced by the “CpCN”
relative to, for example, the commonly employed “CpSiN”
ligand will have an influence on some of the chemical
properties of these compounds and the active catalysts
derived from them.
Olefin Polymerization Experiments. Preliminary
investigations were carried out to study the behavior
of the (“CpCN”)MCl2 and (“CpCN”)MMe2 (M ) Ti, Zr)
derived catalyst systems in olefin polymerization. Test
reactions on ethene homopolymerization and subse-
quently on ethene/1-octene copolymerization reactions
were performed. The catalytic features were very de-
pendent on the specific activation method applied. The
(“CpCN”)TiX2-derived systems were often found less
active catalysts than their (“CpCN”)ZrX2 counterparts,
a trend contrary to what had previously been observed
in the (“CpSiN”)MX2 series.3
Some representative data of ethene polymerization
reactions are listed in Table 3 (see the Supporting
Information for more details and additional polymeri-
zation experiments). It reveals that most of the (“CpCN-
”)TiCl2 systems gave rather low activity ethene polym-
erization catalysts under the applied experimental
conditions when activated with excess methylalumoxane
(MAO, Al/Ti ratio g 500). The 3c/MAO catalyst is more
active (entries 1 and 2 in Table 3), but even this system
is less active than the (“CpSiN”)TiCl2 reference 1a/MAO
(Table 3, entry 9).
1
2
3c
MAO
60
25
25
60
25
25
60
60
60
25
60
60
60
60
60
60
90
60
60
60
5
30
60
60
60
40
60
60
20
30
30
60
30
30
30
10
20
20
3
3.7
5.8
5.4
0.8
1.1
0.5
1.4
4.4
380
100
43
6
10
5
12
37
980
96
6
48
27
2
3c
MAO
3
3d
MAO
4
4c
MAO
5
3b
MAO
6
4b
MAO
7
3a
MAO
8
4a
MAO
9
1a
MAO
37
10
11
12
13
14
15
16
17
18
19
20
17d
17a
17a
18a
18a
18a
19a
19a
19a
19a
19a
MAO
8.5
0.33
5.8
B(C6F5)3
[Ph3C+]c
MAO
1.9
0.15
6.5
16.1
17.8
0
9.4
9.0
B(C6F5)3
[Ph3C+]c
MAO
94
910
1006
MAO
B(C6F5)3
[Ph3C+]c
[Ph3C+]c
3520
3370
3
a In toluene solution, 2 bar ethene pressure, MAO-activated
reactions with Al/M ratios of ca. 500. b Catalyst activities in g(PE)/
[mmol(group 4 metal complex) h bar]-1. Catalyst amounts used:
20 mg except entries 6, 7, 10 (25 mg) and 17, 19, 20 (10 mg).
c [Ph3C+][B(C6F5)3-].
The method of activation seems to be of importance.
Treatment of the (“CpCN”)TiMe2 complexex with B-
(C6F5)3, a method widely used in homogeneous metal-
locene Ziegler-Natta catalyst activation,28 here led to
low activities. In our study, treatment of the (“CpCN”)-
ZrMe2 complex 19a with B(C6F5)3 did not give an active
ethene polymerization catalyst, although 19a turned out
to be a precursor for markedly faster catalysts when
other methods of activation were used. MAO activation
of (“CpCN”)ZrMe2 (19a) gave ethene polymerization
catalysts of activities (entries 16 and 17) equal to those
of the (“CpSiN”)TiCl2/MAO reference system (entry 9).
The (“CpCN”)ZrMe2-derived system even surpassed this
reference when the activation was carried out with trityl
cation as methyl anion abstractor.29 The 19a/[Ph3C+]-
[B(C6F5)4-] catalyst exhibited a more than 3 times
higher activity (Table 3, entries 19 and 20) than the
already fast 1a/MAO reference system in ethene po-
lymerization under our reaction conditions.
Figure 5. View of the molecular structure of the (“CpCN”)-
Zr(CH3)2 complex 19a.
Scheme 8. Cp(centroid)-M-N (deg) Angles and
M-N [Å] Bond Lengths of Some “Constrained
Geometry” Group 4 Metal Complexes and Related
Systems for Comparison
Some of the (“CpCN”)TiCl2/MAO catalysts gave rea-
sonable ethene/1-octene copolymerization activities (see
Table 4, entries 1-4). The ethene/1-octene molar ratio
(24) Carpenetti, D. W.; Kloppenburg, L.; Kupec, J. T.; Petersen, J.
L. Organometallics 1996, 15, 1572-1581.
(25) Go´mez, R.; Go´mez-Sal, P.; Martin, A.; Nu´n˜ez, A.; del Real, P.
A.; Royo, P. J. Organomet. Chem. 1998, 564, 93-100.
(26) Sinnema, P.-J.; Van der Veen, L.; Speck, A. L.; Veldman, N.;
Teuben, J. H. Organometallics 1997, 16, 4245-4247.
(27) Pupi, R. M.; Coalter, J. N.; Petersen, J. L. J. Organomet. Chem.
1995, 497, 17-25.
(28) Massey, A. G.; Park, A. J.; Stone, F. G. A. Proc. Chem. Soc.
1963, 212. Massey, A. G.; Park, A. J. J. Organomet. Chem. 1964, 2,
245-250. Massey, A. G.; Park, A. J. Organometallic Syntheses; King,
R. B., Eisch, J. J., Eds.; Elsevier: New York, 1986; Vol. 3, pp 461-
462. Marks, T. J. Acc. Chem. Res. 1992, 25, 57-65. Yang, X.; Stern,
C. L.; Marks, T. J. J. Am. Chem. Soc. 1994, 116, 10015-10031.
(29) Bochmann, M.; Jaggar, A. J.; Nicholls, J. C. Angew. Chem. 1990,
102, 830-832; Angew. Chem., Int. Ed. Engl. 1990, 29, 780-782. Chien,
J. C. W.; Tsai, W.-M.; Rausch, M. D. J. Am. Chem. Soc. 1991, 113,
8570-8571. Review: Chen, E. Y.-X.; Marks, T. J. Chem. Rev. 2000,
100, 1391-1434.
tems. The Cp(centroid)-Zr-N angle in complex 19a is
only 89.4°, which is ca. 4° smaller than found in its
(“CpCN”)TiMe2 analogue 18a and ca. 7° smaller than
found in complex 18b. We will see whether these very

C1-Bridged Cp/Amido Titanium and Zirconium Systems
Organometallics, Vol. 24, No. 20, 2005 4767
Table 4. Ethene/1-Octene Copolymerization with the (“CpCN”)MX2 (M ) Ti, Zr; X ) Cl or Me) Derived
Catalystsa
c
c
entry
compd
activator
T (°C)
t (min)
g(copol)
ethene/1-octeneb
Mw
Mw/Mn
activityd
1
2
3c
MAO
60
90
60
60
60
60
60
60
90
90
90
20
10
10
10
5
19.3
8.4
3.0
3.6
3.4
3.5
3.4
5.8
3.6
31
7900
6100
6700
5500
52000
21000
29000
2700
1800
6700
7000
1.5
1.5
1.7
3.9
2.1
4.4
1.7
2.0
1.5
1.7
1.6
990
860
3c
MAO
3
3d
MAO
7.2
670
4
4a
MAO
1.6
35.1
1.5
160
14 900
145
1000
1420
2540
2780
3040
5
1a
MAO
6
17a
18a
19a
19a
19a
19a
[Ph3C+]d
[Ph3C+]d
MAO
10
10
5
7
11.4
3.2
8
9
MAO
5
5.6
21
10
11
[Ph3C+]d
[Ph3C+]d
5
6.2
14
14
5
6.7
a Reactions in 50 mL toluene/30 mL 1-octene at 2 bar ethene pressure. b Molar monomer ratio in the copolymer determined by 13C
NMR spectroscopy. c Determined by GPC. d In g(copolymer)/[mmol(group 4 metal complex) h bar]-1. Catalyst amounts used: 20 mg except
entries 5, 8-11 (10 mg). e [Ph3C+][ B(C6F5)4-].
in the random copolymer (as determined by 13C NMR
including deuterated solvents used for NMR spectroscopy,
spectroscopy)30 is similar to that typically observed for
were dried and distilled prior to use. Elemental analyses were
made at a Foss-Heraeus CHN-O-Rapid, and a Nicolet 5DXC
FT-IR spectrometer was used for IR spectra. NMR experiments
were measured using a Bruker AC 200 P, a Varian Inova 500,
the 1a/MAO reference, but the (“CpCN”)TiCl2/MAO
systems are less active than the 1a/MAO system and
give lower molecular weights under the here applied
or a Varian Unity Plus 600 NMR spectrometer. Most assign-
reaction conditions. Again the (“CpCN”)ZrMe2-derived
ments were based on a series of 2D NMR experiments.
catalysts are more active also for ethene/1-octene copo-
lymerization than their (“CpCN”)TiX2 counterparts,
X-ray Crystal Structure Analyses. Data sets were col-
lected with a Nonius KappaCCD diffractometer, equipped with
especially when the activation was carried out by
a rotating anode generator. Programs used: data collection
COLLECT (Nonius B.V., 1998), data reduction Denzo-SMN
(Otwinowski, Z.; Minor, W. Methods Enzymol. 1997, 276, 307-
326), absorption correction SORTAV (Blessing, R. H. Acta
Crystallogr. 1995, A51, 33-37; Blessing, R. H. J. Appl.
Crystallogr. 1997, 30, 421-426) and Denzo (Otwinowski, Z.;
Borek, D.; Majewski, W.; Minor, W. Acta Crystallogr. 2003,
A59, 228-234), structure solution SHELXS-97 (Sheldrick, G.
M. Acta Crystallogr. 1990, A46, 467-473), structure refine-
ment SHELXL-97 (Sheldrick, G. M. Universita¨t Go¨ttingen,
1997), graphics XP (BrukerAXS, 2000).
-
treatment of complex 19a with [Ph3C+][B(C6F5)4
]
(Table 4, entries 9-11), but in this case the 1-octene
incorporation is markedly reduced (see Table 4).
Some Conclusions. It was shown in this study that
the (“CpCN”) group 4 metal dihalides and a variety of
typical organometallic derivates of these complexes can
rather easily be prepared. The synthetic routes allow
for some variation of the substituents at the “CpCN”
complex framework. For the catalytic use of these
systems it seems important that (“CpCN”)M derivates
can now be prepared that feature σ-bonded hydrocarbyl
ligands since this allows the application of a variety of
catalyst activation procedures. The small number of
variations carried out in the course of this study has
already shown that finding the right activation method
may be an important feature for generating active and
selective CC-coupling catalysts from these “CpCN”M-
(IV) precursors. The (“CpCN”)MX2-derived catalysts in
some cases seem to exhibit properties different from
those of the conventional (“CpSiN”)TiX2-derived sys-
tems. The rather small number of experiments carried
out so far may suggest that ion-pairing effects31 could
be significantly determining some of the chemistry of
these very open (“CpCN”)M(IV) complex derived Zie-
gler-Natta catalysts systems. Some of the remarkable
features of the neutral (“CpCN”)MX2 complexes and the
(charged) catalyst systems derived thereof probably
make it worthwhile to explore these interesting new C1-
bridged Cp/amido metal complex systems further.
Preparation of the Lithium Compounds. Preparation
of (1-Phenylamido-2,2-dimethyl)propylcyclopentadie-
nyldilithium (9c). Aniline (2.79 g, 30.0 mmol) was dissolved
in THF (40 mL) and cooled to 0 °C. n-BuLi (1.69 M in hexane,
17.8 mL, 30.0 mmol) was added dropwise. The solution was
stirred at room temperature for 30 min and then cooled to -78
°C. 6-tert-Butylfulvene (7) (4.02 g, 30.0 mmol) in THF (10 mL)
was slowly added. The mixture was warmed slowly to room
temperature followed by stirring for 2 h to give a solution
whose yellow color faded away. The solution was cooled to -78
°C, and n-BuLi (1.69 M in hexane, 17.8 mL, 30.0 mmol) was
added dropwise. The mixture was stirred overnight, while it
warmed to room temperature. THF was removed, and the
residue was washed with pentane and dried under vacuum to
1
give a white powder of 9c (9.82 g, 27.4 mmol, 91%). H NMR
experiment suggested the product contained 1.65 equiv of
THF. 1H NMR (200.1 MHz, d6-DMSO, 298 K): δ 6.89 (m, 2H,
m-Ph), 6.55 (m, 2H, o-Ph), 6.29 (m, 1H, p-Ph), 5.28, 5.17 (each
m, each 2H, Cp), 3.89 (s, 1H, 6-H), 0.91 (s, 9H, 8-H). 13C{1H}
NMR (50.3 MHz, d6-DMSO, 298 K): δ 128.2 (m-Ph), 113.6 (p-
Ph),112.6 (o-Ph), 102.6, 101.7 (C-1/C-2/C-3/C-4), 64.8 (C-6), 36.2
(C-7), 27.7 (C-8).
Preparation of (1-tert-Butylamido-2,2-dimethyl)pro-
pylcyclopentadienyldilithium (9d). Lithium N-tert-buty-
lamide (3.16 g, 40.0 mmol) was dissolved in THF (40 mL) and
cooled to -78 °C. 6-tert-Butylfulvene (7) (5.36 g, 40.0 mmol)
in THF (10 mL) was slowly added. The mixture was warmed
slowly to room temperature followed by stirring overnight to
give a light yellow solution. The solution was cooled to -78
°C, and n-BuLi (1.68 M in hexane, 23.8 mL, 40.0 mmol) was
added dropwise. The mixture was stirred overnight while it
warmed to room temperature. THF was removed, and the
residue was washed with pentane and dried under vacuum to
Experimental Section
General Comments. All reactions were carried out under
argon using Schlenk-type glassware or in a glovebox. Solvents,
(30) Randall, J. C. JMS-Rev. Macromol. Chem. Phys. 1989, C29
(2&3), 201-317. See also: Wang, W. J.; Kolodka, E.; Zhu, S.; Hamielec,
A. E. J. Polym. Sci: A 1999, 37, 2949-2957. Liu, W.; Ray, D. G., III;
Rinaldi, P. L. Macromolecules 1999, 32, 3817-3819.
(31) Lanza, G.; Fragala`, I. L.; Marks, T. J. J. Am. Chem. Soc. 1998,
120, 8257-8258. Lanza, G.; Fragala`, I. L.; Marks, T. J. J. Am. Chem.
Soc. 2000, 122, 12764-12777.

4768 Organometallics, Vol. 24, No. 20, 2005
Wang et al.
a white powder of 9d (10.48 g, 38.4 mmol, 96%). 1H NMR
(20 mL), a brown powder of 14b (9.73 g, 29.0 mmol, 97%) was
obtained. The 1H NMR spectrum of the product revealed that
the dilithium salt contained 1.5 equiv of THF. 1H NMR (200.1
MHz, d6-benzene/d8-tetrahydrofuran, 10:1, 298 K): δ 6.82, 6.58
1
suggested the product contained 0.75 equiv of THF. H NMR
(200.1 MHz, d6-DMSO, 298 K): δ 5.13 (ps, 4H, Cp), 3.00 (s,
1H, 6-H), 0.87 (s, 9H, 10-H), 0.78 (s, 9H, 8-H). 13C{1H} NMR
(50.3 MHz, d6-DMSO, 298 K): δ 123.4 (C-5), 101.9, 101.1 (C-
1/C-2/C-3/C-4), 62.6 (C-6), 50.1 (C-9), 35.5 (C-7), 30.6 (C-10),
28.0 (C-8).
(each d, 3JHH ) 8.7 Hz, each 2H, Ph), 5.99 (b, 4H, Cp), 4.48 (q,
3
3JHH ) 5.9 Hz, 1H, 6-H), 3.54 (s, 3H, OCH3), 1.63 (d, JHH
)
5.9 Hz, 3H, 7-H). 13C{1H} NMR (50.3 MHz, d6-benzene/d8-
tetrahydrofuran, 10:1, 298 K): δ 155.7, 147.4 (ipso-Ph), 130.4
(C-5), 116.0, 113.7, 103.2, 102.6 (Ph and Cp), 67.8 (OCH3), 56.5
(C-6), 25.7 (C-7).
Preparation of [1-(o-Methoxyphenylamido)-2,2-dim-
ethyl]propylcyclopentadienyldilithium (9a). By the same
method used in the preparation of compound 9c, from o-
anisidine (3.69 g, 30.0 mmol) and 6-tert-butylfulvene (7) (4.02
g, 30.0 mmol), a pale gray powder of 9a (11.89 g, 28.5 mmol,
95%) was obtained. 1H NMR suggested the product contained
2.0 equiv of THF. 1H NMR (200.1 MHz, d6-benzene/d8-
tetrahydrofuran, 10:1, 298 K): δ 6.58, 6.37, 5.74 (each m, 4H,
Ph), 5.86 (ps, 4H, Cp), 3.98 (s, 1H, 6-H), 3.47 (s, 3H, OCH3),
1.11 (s, 9H, 8-H). 13C{1H} NMR (50.3 MHz, d6-benzene/d8-
tetrahydrofuran, 10:1, 298 K): δ 153.3, 149.3 (ipso-Ph), 123.4
(C-5), 125.1, 106.6, 103.5, 100.9, 100.5 (Ph and Cp, the peak
at 100.9 ppm shows double intensity), 67.8 (OCH3), 53.5 (C-
6), 36.0 (C-7), 28.9 (C-8).
Preparation of [1-(o-Methoxyphenylamido)ethyl]cy-
clopentadienyldilithium (14a). By the method used in
preparation of compound 14b, from o-anisidine (3.69 g, 30.0
mmol) and 6-(dimethylamino)fulvene (11) (3.63 g, 30.0 mmol),
a brown powder of 14a (8.31 g 29.0 mmol, 97%) was obtained.
The 1H NMR spectrum of the product revealed that the
dilithium salt contained 0.75 equiv of THF. 1H NMR (200.1
MHz, d8-tetrahydrofuran, 298 K): δ 6.49, 6.33, 6.18, 5.64 (each
m, each 1H, Ph), 5.71, 5.57 (each m, each 2H, Cp), 4.29 (q,
3
3JHH ) 6.2 Hz, 1H, 6-H), 3.63 (s, 3H, OCH3), 1.37 (d, JHH
)
6.2 Hz, 3H, 7-H). 13C{1H} NMR (50.3 MHz, d8-tetrahydrofuran,
298 K): δ 152.2, 149.5 (ipso-Ph), 130.7 (C-5), 123.8, 107.0,
106.3, 102.5, 101.7 (Ph and Cp, the peak at 101.7 ppm shows
double intensity), 68.3 (OCH3), 54.2 (C-6), 26.3 (C-7).
Synthesis of CpCN-Titanium and -Zirconium Dia-
mides. General Procedure. The dilithium salt ligand was
dissolved in THF (10 mL THF/g lithium salt) and added slowly
to a solution of bis(diamido)dichlorotitanium or bis(diamido)-
dichlorozirconium (1 equiv) in THF (5 mL THF/g lithium salt)
at -78 °C. The mixture was warmed to room temperature and
stirred for 2 h. THF was removed, and the residue was
extracted with pentane (3 × 20 mL). Removal of pentane gave
a dark red oil (sometimes solid). The product was checked by
1H NMR and was used for the chlorination reaction without
further purification.
Preparation of [1-(p-Methoxyphenylamido)-2,2-dim-
ethyl]propylcyclopentadienyldilithium (9b). By the same
method used in the preparation of compound 9c, from p-
anisidine (3.69 g, 30.0 mmol) and 6-tert-butylfulvene (8) (4.02
g, 30.0 mmol), a yellow powder of 9b (8.83 g, 27.3 mmol, 91%)
1
was obtained. H NMR suggested the product contained 0.75
equiv of THF. 1H NMR (200.1 MHz, d6-DMSO, 298 K): δ 6.58,
6.50 (each d, 3JHH ) 9.2 Hz, each 2H, Ph), 5.26, 5.16 (each m,
each 2H, Cp), 3.77 (s, 1H, 6-H), 3.58 (s, 3H, OCH3), 0.91 (s,
9H, 8-H). 13C{1H} NMR (50.3 MHz, d6-DMSO, 298 K): δ 149.5,
145.5 (ipso-Ph), 119.1 (C-5), 114.2, 113.6 (Ph), 102.6, 101.7 (C-
1/C-2/C-3/C-4), 66.0 (OCH3), 55.5 (C-6), 36.1 (C-7), 27.8 (C-8).
Preparation of [1-(Phenylamido)ethyl]cyclopentadi-
enyldilithium (14c). Method 1. MeLi (2.0 M in ether, 4.0
mL, 8.0 mmol) was added dropwise to a solution of (N-
phenylformimidoyl)cyclopentadienyllithium (13c) (1.40 g, 8.0
mmol) in ether (25 mL) at -78 °C. The reaction mixture was
warmed slowly to room temperature and stirred for 14 h. Ether
was removed under vacuum; the remaining brown powder was
washed with pentane and dried under vacuum to get 14c (9.82
g, 7.26 mmol, 91%). 1H NMR suggested the dilithium salt was
coordinated with one-third of an equivalent of ether. 1H NMR
(200.1 MHz, d6-benzene/d8-tetrahydrofuran, 10:1, 298 K): δ
7.17 (m, 2H, m-Ph), 6.64 (m, 2H, o-Ph), 6.44 (m, 1H, p-Ph),
5.95 (b, 4H, Cp), 4.51 (q, 3JHH ) 5.9 Hz, 1H, 6-H), 1.64 (d, 3JHH
) 5.9 Hz, 3H, 7-H).
Preparation of Bis(dimethylamido)[η5:[1-(o-methoxy-
phenylamido)-2,2-dimethylpropyl]cyclopentadienyl-
KN,O]titanium (10a). From [1-(o-methoxyphenylamido)-2,2-
dimethylpropyl]cyclopentadienyldilithium (9a) (2.0 THF ad-
duct, 6.26 g, 15.0 mmol) and bis(dimethylamido)dichlorotita-
nium (3.10 g, 15.0 mmol) a dark red oil of 10a was obtained.
1H NMR (200.1 MHz, d6-benzene, 298 K): δ 7.60, 6.87, 6.58
(each br, 4H, Ph), 6.28, 6.14, 5.90 (each br, 4H, Cp), 5.55 (br,
1H, 6-H), 3.36 (br, 3H, OCH3), 3.06, 2.86 (each s, each 6H,
(NCH3)2), 1.14 (s, 9H, 8-H).
Preparation of Bis(dimethylamido)[η5:[1-(p-methoxy-
phenylamido)-2,2-dimethylpropyl]cyclopentadienyl-
KN]titanium (10b). From [1-(p-methoxylphenylamido)-2,2-
dimethylpropyl]cyclopentadienyldilithium (9b) (0.75 THF ad-
duct, 4.85 g, 15.0 mmol) and bis(dimethylamido)dichlorotita-
nium (3.10 g, 15.0 mmol) a dark red oil of 10b was obtained.
1H NMR (200.1 MHz, d6-benzene, 298 K): δ 6.97, 6.80 (each
m, each 2H, Ph), 6.18, 6.13, 5.85, 5.74 (each m, each 1H, Cp),
4.79 (s, 1H, 6-H), 3.39 (s, 3H, OCH3), 3.03, 2.88 (each s, each
6H, (NCH3)2), 1.14 (s, 9H, 8-H).
Method 2. Lithium anilide (41.3 mmol) was prepared by
adding n-BuLi (1.74 M in hexane, 41.3 mL, 41.3 mmol) to a
solution of aniline (3.84 g, 41.3 mmol) in THF (20 mL) at -78
°C. The reaction mixture was stirred at room temperature for
1 h. The solution of lithium anilide was added slowly to a
solution of 6-(dimethylamino)fulvene (9) (5.00 g, 41.3 mmol)
in THF (20 mL), and the reaction mixture was stirred
overnight. The reaction mixture was concentrated under
vacuum to near dryness, and then 50 mL of ether was added.
At -78 °C, MeLi (2.04 M in ether, 20.3 mL, 41.3 mmol) was
added slowly, and the reaction mixture was stirred overnight.
All volatiles were removed under vacuum. The residue was
washed with pentane and dried under vacuum to give 14c
Preparation of Bis(dimethylamido)[η5:[1-(phenylami-
do)-2,2-dimethylpropyl]cyclopentadienyl-KN]titanium
(10c). From [1-(phenylamido)-2,2-dimethylpropyl]cyclopenta-
dienyldilithium (9c) (1.65 equiv THF adduct, 4.22 g, 11.8
mmol) and bis(dimethylamido)dichlorotitanium (2.44 g, 11.8
mmol) a dark red oil of 10c was obtained. 1H NMR (200.1 MHz,
d6-benzene, 298 K): δ 7.20 (m, 2H, m-Ph), 7.06 (m, 2H, o-Ph),
6.78 (m, 1H, p-Ph), 6.14, 6.11, 5.80, 5.71 (each m, each 1H,
Cp), 4.87 (s, 1H, 6-H), 3.01, 2.84 (each s, each 6H, N(CH3)2),
1.13 (s, 9H, 8-H).
1
(10.96 g, 40.7 mmol, 98%) as a brown powder. The H NMR
spectrum of the product revealed the dilithium salt was
coordinated with 1 equiv of THF. 1H NMR (200.1 MHz, d6-
benzene/d8-tetrahydrofuran, 10:1, 298 K): δ 7.01 (m, 2H,
m-Ph), 6.60 (m, 2H, o-Ph), 6.22(m, 1H, p-Ph), 5.93 (b, 4H, Cp),
3
3
Preparation of Bis(dimethylamido)[η5:[1-(tert-butyla-
mido)-2,2-dimethylpropyl]cyclopentadien-yl-KN]titani-
um (10d). From (1-tert-butylamido-2,2-dimethyl)propylcyclo-
pentadienyldilithium (9d) (0.75 THF adduct, 4.10 g, 15.0
mmol) and bis(dimethylamido)dichlorotitanium (3.10 g, 15.0
mmol) a dark red oil of 10d was obtained. 1H NMR (200.1
4.49 (q, JHH ) 5.9 Hz, 1H, 6-H), 1.49 (d, JHH ) 5.9 Hz, 3H,
7-H).
Preparation of [1-(p-Methoxyphenylamido)ethyl]cy-
clopentadienyldilithium (14b). By method 2 used in prepa-
ration of compound 14c, from p-anisidine (3.69 g, 30.0 mmol)
and 6-(dimethylamino)fulvene (9) (3.63 g, 30.0 mmol) in THF

C1-Bridged Cp/Amido Titanium and Zirconium Systems
Organometallics, Vol. 24, No. 20, 2005 4769
(1)°, V ) 1026.0(2) Å3, Fcalc ) 1.360 g cm-3, µ ) 6.86 cm-1
MHz, d6-benzene, 298 K): δ 6.24, 5.71, 5.60, 5.45 (each m, each
1H, Cp), 4.39 (s, 1H, 6-H), 3.08, 2.91 (each s, each 6H, (NCH3)2),
1.33, 1.24 (each s, each 9H, 8-H/10-H).
,
empirical absorption correction (0.821 e T e 0.875), Z ) 2,
triclinic, space group P1h (No. 2), λ ) 0.71073 Å, T ) 198 K, ω
and æ scans, 9375 reflections collected ((h, (k, (l), [(sin θ)/λ]
) 0.66 Å-1, 4830 independent (Rint ) 0.039) and 4246 observed
Preparation of Bis(dimethylamido)[η5:[1-(o-methoxy-
phenylamido)ethyl]cyclopentadienyl-KN,O]titanium
(15a). From [1-(o-methoxyphenylamido)ethyl]cyclopentadienyl-
dilithium (14a) (0.75 THF adduct, 4.22 g, 15.0 mmol) and bis-
(dimethylamido)dichlorotitanium (3.10 g, 15.0 mmol), a dark
red oil of 15a was obtained. 1H NMR (200.1 MHz, d6-benzene,
298 K): δ 6.83, 6.65-6.59 (4H, Ph), 6.09, 5.80 (each m, each
2
reflections [I g 2σ(I)], 255 refined parameters, R ) 0.035, Rw
) 0.096, max. residual electron density 0.28 (-0.34) e Å-3
,
toluene refined with geometrical restraints, hydrogen atoms
calculated and refined as riding atoms.
Preparation of [η5:[1-(p-Methoxyphenylamido)-2,2-
dimethylpropyl]cyclopentadienyl-KN]dichlorotitani-
um (3b). After treatment of bis(dimethylamido)[η5:[1-(meth-
oxyphenylamido)-2,2-dimethylpropyl]cyclopentadienyl-
κN]titanium (10b) [prepared from 9b (4.85 g, 15.0 mmol) and
TiCl2(NMe2)2 (3.10 g, 15.0 mmol)] with 18 mL of dichlorodim-
ethylsilane (18.58 g, 144 mmol) in 20 mL of toluene at 50 °C
for 1 h, the reaction mixture was filtered, and the filtrate was
slowly cooled to -30 °C and stored overnight at this temper-
ature (3b: 3.47 g, 9.3 mmol, 62%). The dark brown precipitated
powder was collected by filtration and dried under vacuum.
Suitable X-ray crystals were obtained by slow diffusion of
pentane into a solution of this dichloride in toluene. Anal.
Calcd for C17H21Cl2NOTi (374.1): C 54.58, H 5.66, N 3.74.
Found: C 54.33, H 5.66, N 3.36. 1H NMR (499.8 MHz,
d6-benzene, 298 K): δ 7.15 (m, 2H, 10-H), 6.74 (m, 2H, 11-H),
6.29 (m, 1H, 1-H), 6.26 (m, 1H, 2-H), 6.23 (m, 1H, 3-H), 5.91
(m, 1H, 4-H), 4.98 (s, 1H, 6-H), 3.23 (s, 3H, 13-H), 0.79 (s, 9H,
8-H). 13C{1H} NMR (125.7 MHz, d6-benzene, 298 K): δ 158.2
(C-12), 147.4 (C-9), 125.2 (C-4), 123.3 (C-1), 120.7 (C-2), 120.1
(C-3), 119.8 (C-10), 114.8 (C-11), 110.8 (C-5), 70.5 (C-6), 54.9
(C-13), 36.6 (C-7), 27.8 (C-8). X-ray crystal structure analysis
of 3b: formula C17H21NOTiCl2, M ) 374.15, dark red crystal
0.45 × 0.40 × 0.15 mm, a ) 8.950(1) Å, b ) 14.276(1) Å, c )
15.915(1) Å, R ) 64.89(1)°, â ) 88.06(1)°, γ ) 80.45(1)°, V )
1814.3(3) Å3, Fcalc ) 1.370 g cm-3, µ ) 7.67 cm-1, empirical
absorption correction (0.724 e T e 0.894), Z ) 4, triclinic, space
group P1h (No. 2), λ ) 0.71073 Å, T ) 198 K, ω and æ scans,
3
1H, Cp), 5.90 (m, 2H, Cp), 5.10 (q, JHH ) 6.2 Hz, 1H, 6-H),
3.44 (s, 3H, OCH3), 2.88, 2.85 (each s, each 6H, NCH3), 1.35
3
(d, JHH ) 6.2 Hz, 3H, 7-H).
Preparation of Bis(dimethylamido)[η5:[1-(p-methoxy-
phenylamido)ethyl]cyclopentadienyl-KN]titanium (15b).
From
[1-(p-methoxyphenylamido)ethyl]cyclopentadienyl-
dilithium (14b) (1.5 THF adduct, 5.03 g, 15.0 mmol) and bis-
(dimethylamido)dichlorotitanium (3.10 g, 15.0 mmol), a dark
red oil of 15b was obtained. 1H NMR (200.1 MHz, d6-benzene,
298 K): δ 6.92 (ps, 4H, Ph), 6.11, 6.06 (each m, each 1H, Cp),
5.87 (m, 2H, Cp), 4.94 (q, 3JHH ) 6.2 Hz, 1H, 6-H), 3.44 (s, 3H,
3
OCH3), 3.03, 2.99 (each s, each 6H, (NCH3)2), 1.46 (d, JHH
6.2 Hz, 3H, 7-H).
)
Preparation of Bis(dimethylamido)[η5:[1-(phenylami-
do)ethyl]cyclopentadienyl-KN]titanium (15c). From [1-(phe-
nylamido)ethyl]cyclopentadienyldilithium (14c) (1.0 equiv THF
adduct, 5.40 g, 20.0 mmol) and bis(dimethylamido)dichloroti-
tanium (4.12 g, 20.0 mmol), a red powder of 15c was obtained.
1H NMR (200.1 MHz, d6-benzene, 298 K): δ 7.29 (m, 2H,
m-Ph), 6.98 (m, 2H, o-Ph), 6.81 (m, 1H, p-Ph), 6.09, 6.02 (each
m, each 1H, Cp), 5.85 (m, 2H, Cp), 4.94 (q, 3JHH ) 6.2 Hz, 1H,
3
6-H), 3.00, 2.96 (each s, each 6H, NCH3), 1.44 (d, JHH ) 6.2
Hz, 3H, 7-H).
Preparation of Bis(dimethylamido)[η5:[1-(o-methoxy-
phenylamido)-2,2-dimethylpropyl]cyclopentadienyl-
KN,O]zirconium (16a). From [1-(o-methoxyphenylamido)-2,2-
dimethylpropyl]cyclopentadienyldilithium (9a) (2.0 THF ad-
duct, 4.17 g, 10.0 mmol) and bis(dimethylamido)dichlorozir-
coniumbis(tetrahydrofuran) (25) (3.94 g, 10.0 mmol), a brown
oil of 16a was obtained. 1H NMR (200.1 MHz, d6-benzene, 298
K): δ 6.97, 6.78, 6.48 (each m, 4H, Ph), 6.28, 6.11, 6.04, 5.77
(each m, each 1H, Cp), 4.80 (s, 1H, 6-H), 3.63 (s, 3H, OCH3),
2.78, 2.41 (each s, each 6H, N(CH3)2), 1.25 (s, 9H, 8-H).
Synthesis of CpCN-Titanium or -Zirconium Dichlo-
ride Complexes. Preparation of [η5:[1-(o-Methoxyphe-
nylamido)-2,2-dimethylpropyl]cyclopentadienyl-KN,O]-
dichlorotitanium (3a). After treatment of bis(dimethyl-
amido)[η5:[1-(o-methoxyphenylamido)-2,2-dimethylpropyl]-
cyclopentadienyl-κN,O]titanium (10a) [prepared from 9a (6.26
g, 15.0 mmol) and TiCl2(NMe2)2 (3.10 g, 15.0 mmol)] with 18
mL of dichlorodimethylsilane (18.58 g, 144 mmol) in 20 mL of
toluene at 50 °C for 2 h, the reaction mixture was slowly cooled
to -30 °C. The dark brown precipitated powder was collected
by filtration and dried in a vacuum (3a: 4.86 g, 11.6 mmol,
77%). Suitable X-ray crystals were obtained by slow diffusion
of pentane into a solution of this dichloride in toluene. 1H NMR
experiment and X-ray crystal structure analysis suggested that
complex 3a contained 0.5 equiv of toluene. Anal. Calcd for
C17H21Cl2NOTi 0.5C7H8 (420.2): C 58.60, H 6.00, N 3.33.
Found C 58.43, H 6.01, N 3.10. 1H NMR (499.8 MHz,
d6-benzene, 298 K): δ 6.77 (m, 1H, 11-H), 6.75 (m, 1H, 3-H),
6.62 (m, 1H, 2-H), 6.58 (m, 1H, 12-H), 6.56 (m, 1H, 13-H), 6.41
(m, 1H, 10-H), 6.25 (m, 1H, 1-H), 5.70 (m, 1H, 4-H), 4.82 (s,
1H, 6-H), 4.35 (s, 3H, 15-H), 0.92 (s, 9H, 8-H). 13C{1H} NMR
(125.7 MHz, d6-benzene, 298 K): δ 153.4 (C-14), 145.0 (C-9),
125.7 (C-3), 124.6 (C-2), 122.2 (C-4), 120.9 (C-12), 120.4 (C-
11), 119.0 (C-1), 111.9 (C-5), 109.8 (C-13), 106.0 (C-10), 68.5
(C-6), 59.4 (C-15), 36.9 (C-7), 29.8 (C-8). X-ray crystal structure
analysis of 3a: formula C17H21NOTiCl2‚0.5 C7H8, M ) 420.21,
red crystal 0.30 × 0.25 × 0.20 mm, a ) 9.118(1) Å, b ) 10.196-
(1) Å, c ) 11.842(1) Å, R ) 78.07(1)°, â ) 73.09(1)°, γ ) 81.50-
19 626 reflections collected ((h, (k, (l), [(sin θ)/λ] ) 0.66 Å-1
,
8575 independent (Rint ) 0.039) and 7204 observed reflections
2
[I g 2σ(I)], 405 refined parameters, R ) 0.034, Rw ) 0.092,
max. residual electron density 0.34 (-0.36) e Å-3, hydrogen
atoms calculated and refined as riding atoms.
Preparation of [η5:[1-(Phenylamido)-2,2-dimethylpro-
pyl]cyclopentadienyl-KN]dichlorotitanium (3c). After treat-
ment of bis(dimethylamido)[η5:[1-(phenylamido)-2,2-dimeth-
ylpropyl]cyclopentadienyl-κN]titanium (10c) [prepared from 9c
(4.22 g, 11.8 mmol) and TiCl2(NMe2)2 (2.44 g, 11.8 mmol)] with
15 mL of dichlorodimethylsilane (15.48 g, 120 mmol) in 20 mL
of toluene at 50 °C for 1 h, the reaction mixture was filtered,
and the filtrate was cooled to -30 °C and stored overnight at
this temperature. The brown precipitated powder was collected
by filtration and dried in a vacuum (3c: 2.63 g, 7.6 mmol,
65%). Anal. Calcd for C16H19Cl2NTi (344.1): C 55.85, H 5.57,
N 4.07. Found: C 55.33, H 5.66, N 4.02. 1H NMR (200.1 MHz,
d6-benzene, 298 K): δ 7.26-7.10 (m, 4H, o-Ph/m-Ph), 6.82 (m,
1H, p-Ph), 6.26 (m, 3H, Cp), 5.88 (m, 1H, Cp), 5.03 (s, 1H, 6-H),
1
0.77 (s, 9H, 8-H). H NMR (599.9 MHz, d2-dichloromethane,
298 K): δ 7.44 (m, 2H, m-Ph), 7.24 (m, 2H, o-Ph), 7.14 (m,
1H, p-Ph), 6.93 (m, 1H, 2-H), 6.92 (m, 1H, 3-H), 6.76 (m, 1H,
1-H), 6.48 (m, 1H, 4-H), 5.57 (s, 1H, 6-H), 1.04 (s, 9H, 8-H).
13C{1H} NMR (150.8 MHz, d2-dichloromethane, 298 K):
δ
153.6 (ipso-Ph), 129.7 (m-Ph), 126.7 (C-4), 126.2 (p-Ph), 124.6
(C-1), 121.7 (C-2), 121.3 (C-3), 118.6 (o-Ph), 111.6 (C-5), 70.9
(C-6), 37.2 (C-7), 28.1 (C-8).
Preparation of [η5:[1-(tert-Butylamido)-2,2-dimethyl-
propyl]cyclopentadienyl-KN]dichlorotitanium (3d). Bis-
(dimethylamido)[η5:[1-(tert-butylamido)-2,2-dimethylpropyl]-
cyclopentadienyl-κN]titanium (10d) [prepared from 9d (4.10
g, 15.0 mmol) and TiCl2(NMe2)2 (3.10 g, 15.0 mmol)] was
dissolved in 20 mL of toluene. To the solution was added 18
mL of dichlorodimethylsilane (18.58 g, 144 mmol). The mixture

4770 Organometallics, Vol. 24, No. 20, 2005
Wang et al.
was stirred at 50 °C for 1 h. All volatiles were removed. The
residue was extracted with pentane (3 × 30 mL). After
filtration, the pentane solution was stored at -30 °C overnight.
The precipitated yellow solid were collected by filtration and
dried under vacuum (3d: 1.89 g, 5.8 mmol, 39%). Suitable
X-ray crystals were obtained by slow diffusion of pentane into
a solution of this dichloride in toluene. Anal. Calcd for C14H23-
Cl2NTi (324.1): C 51.88, H 7.15, N 4.32. Found: C 51.54, H
7.05, N 4.40. 1H NMR (599.9 MHz, d6-benzene, 298 K): δ 6.39
(m, 1H, 3-H), 6.25 (m, 1H, 2-H), 6.04 (m, 1H, 1-H), 5.53 (m,
1H, 4-H), 4.38 (s, 1H, 6-H), 1.46 (s, 1H, 10-H), 0.93 (s, 1H,
8-H). 13C{1H} NMR (150.8 MHz, d6-benzene, 298 K): δ 125.0
(C-4), 121.9 (C-3), 121.5 (C-2), 121.4 (C-1), 110.5 (C-5), 71.9
(C-6), 62.4 (C-9), 35.7 (C-7), 29.9 (C-10), 29.0 (C-8). X-ray
crystal structure analysis of 3d: formula C14H23NTiCl2, M )
324.13, orange crystal 0.30 × 0.20 × 0.20 mm, a ) 15.058(1)
Å, b ) 18.737(1) Å, c ) 12.564(1) Å, â ) 114.18(1)°, V ) 3233.8-
(4) Å3, Fcalc ) 1.332 g cm-3, µ ) 8.44 cm-1, empirical absorption
correction (0.786 e T e 0.849), Z ) 8, monoclinic, space group
P21/c (No. 14), λ ) 0.71073 Å, T ) 198 K, ω and æ scans, 30 503
reflections collected ((h, (k, (l), [(sin θ)/λ] ) 0.66 Å-1, 7659
independent (Rint ) 0.059) and 6068 observed reflections [I g
precipitated dark brown powder was collected by filtration and
dried under vacuum (4b: 4.30 g, 11.4 mmol, 76%). Suitable
X-ray crystals were obtained by slow diffusion of pentane into
a solution of this dichloride in toluene. 1H NMR and X-ray
crystal structure analysis suggested that complex 4b contained
0.5 equiv of toluene. Anal. Calcd for C14H15Cl2NOTi 0.5C7H8
(378.1): C 55.59, H 5.06, N 3.70. Found: C 55.66, H 5.05, N
3.59. 1H NMR (499.8 MHz, d6-benzene, 298 K): δ 7.31 (m, 2H,
9-H), 6.72 (m, 2H, 10-H), 6.24 (m, 1H, 2-H), 6.20 (m, 1H, 3-H),
3
6.05 (m, 1H, 1-H), 5.86 (m, 1H, 4-H), 5.01 (q, JHH ) 6.4 Hz,
1H, 6-H), 3.25 (s, 3H, 12-H), 1.01 (d, 3JHH ) 6.4 Hz, 3H, 7-H).
13C{1H} NMR (125.7 MHz, d6-benzene, 298 K): δ 157.7 (C-
11), 147.4 (C-8), 123.5 (C-4), 121.4 (C-1), 120.5 (C-3), 120.1 (C-
2), 115.8 (C-9), 114.1 (C-10), 112.1 (C-5), 55.0 (C-12), 54.8 (C-
6), 15.3 (C-7). X-ray crystal structure analysis of 4b: formula
C14H15NOTiCl2‚0.5 C7H8, M ) 378.14, red crystal 0.35 × 0.30
× 0.10 mm, a ) 8.739(1) Å, b ) 9.758(1) Å, c ) 11.401(1) Å, R
) 91.13(1)°, â ) 95.52(1)°, γ ) 112.59(1)°, V ) 891.8(2) Å3,
Fcalc ) 1.408 g cm-3, µ ) 7.81 cm-1, empirical absorption
correction (0.772 e T e 0.926), Z ) 2, triclinic, space group
P1h (No. 2), λ ) 0.71073 Å, T ) 198 K, ω and æ scans, 9961
reflections collected ((h, (k, (l), [(sin θ)/λ] ) 0.67 Å-1, 4219
independent (Rint ) 0.035) and 3787 observed reflections [I g
2
2σ(I)], 337 refined parameters, R ) 0.078, Rw ) 0.196, max.
residual electron density 0.51 (-0.43) e Å-3, two almost
identical molecules in the asymmetric unit, crystals are always
of relatively poor quality, hydrogen atoms calculated and
refined as riding atoms.
2σ(I)], 214 refined parameters, R ) 0.035, Rw ) 0.094, max.
2
residual electron density 0.29 (-0.30) e Å-3, toluene refined
with split positions, hydrogen atoms calculated and refined
as riding atoms.
Preparation of [η5:[1-(o-Methoxyphenylamido)ethyl]-
cyclopentadienyl-KN,O]dichlorotitanium (4a). Bis(dim-
ethylamido)[η5:[1-(o-methoxyphenylamido)ethyl]cyclo-
pentadienyl-κN,O]titanium (15a) [prepared from 14a (4.22 g,
15.0 mmol) and TiCl2(NMe2)2 (3.10 g, 15.0 mmol)] was dis-
solved in 50 mL of toluene, and 20 mL of dichlorodimethylsi-
lane (20.64 g, 160 mmol) was added. After it was stirred at 50
°C for 8 h, the mixture was cooled slowly to room temperature
and finally stored at -30 °C overnight. The precipitated brown
powder was collected by filtration and dried under vacuum
(4a: 4.48 g, 13.5 mmol, 90%). Suitable X-ray crystals were
obtained by slow diffusion of ether to a solution of the
dichloride in dichloromethane, THF, and toluene. Anal. Calcd
for C14H15Cl2NOTi (332.1): C 50.64, H 4.55, N 4.22. Found:
C 49.76, H 4.04, N 2.98. 1H NMR (499.8 MHz, d2-dichlo-
romethane, 298 K): δ 7.18 (m, 1H, 12-H), 7.07 (m, 1H, 3-H),
7.05 (m, 1H, 2-H), 7.04 (m, 1H, 10-H), 6.97 (m, 1H, 11-H), 6.51
(m, 1H, 9-H), 6.45 (m, 1H, 1-H), 6.27 (m, 1H, 4-H), 5.47 (q,
3JHH ) 6.4 Hz, 1H, 6-H), 4.60 (s, 3H, 14-H), 1.71 (d, 3JHH ) 6.4
Hz, 3H, 7-H). 13C{1H} NMR (125.7 MHz, d2-dichloromethane,
298 K): δ 153.0 (C-13), 143.0 (C-8), 125.7 (C-3), 125.2 (C-2),
121.9 (C-10), 121.8 (C-11), 121.3 (C-4), 118.2 (C-1), 114.6 (C-
1), 109.9 (C-12), 105.0 (C-9), 59.3 (C-14), 54.3 (C-6), 16.4 (C-
7). X-ray crystal structure analysis of 4a: formula C14H15-
NOTiCl2, M ) 332.07, red crystal 0.30 × 0.20 × 0.05 mm, a )
18.280(1) Å, b ) 8.406(1) Å, c ) 9.450(1) Å, V ) 1452.1(2) Å3,
Fcalc ) 1.519 g cm-3, µ ) 9.47 cm-1, empirical absorption
correction (0.764 e T e 0.954), Z ) 4, orthorhombic, space
group Pca21 (No. 29), λ ) 0.71073 Å, T ) 198 K, ω and æ scans,
Preparation of [η5:[1-(Phenylamido)ethyl]cyclopen-
tadienyl-KN]dichlorotitanium (4c). Bis(dimethylamido)[η5:
[1-(N-phenylamido)ethyl]cyclopentadienyl-κN]titanium (15c)
[prepared from 14c (5.40 g, 20.0 mmol) and TiCl2(NMe2)2 (4.12
g, 20.0 mmol)] was dissolved in 50 mL of toluene, and 10 mL
of dichlorodimethylsilane (10.32 g, 80 mmol) was added. The
mixture was stirred at 50 °C for 3 h. Then most of the
dichlorodimethylsilane was removed under reduced pressure.
The remaining solution was filtered through Celite. The
filtrate was concentrated to about 30 mL, and 15 mL of
pentane was slowly added. The mixture was stored overnight
at -30 °C. The precipitated dark red crystals were collected
by filtration and dried under vacuum (4c: 6 g, 0.1 mmol, 80%).
Anal. Calcd for C13H13Cl2NTi (302.0): C 51.69, H 4.34, N 4.64.
Found: C 51.45, H 4.42, N 4.67. 1H NMR (599.9 MHz,
d6-benzene, 298 K): δ 7.33 (m, 2H, o-Ph), 7.14 (m, 2H, m-Ph),
6.80 (m, 1H, p-Ph), 6.21 (m, 1H, 2-H), 6.16 (m, 1H, 3-H), 6.01
3
(m, 1H, 1-H), 5.81 (m, 1H, 4-H), 4.97 (q, JHH ) 6.6 Hz, 1H,
3
6-H), 0.99 (d, JHH ) 6.6 Hz, 3H, 7-H). 13C{1H} NMR (150.8
MHz, d6-benzene, 298 K): δ 151.8 (ipso-Ph), 129.0 (m-Ph),
125.3 (p-Ph), 123.8 (C-4), 121.6 (C-1), 120.8 (C-3), 120.4 (C-2),
114.2 (o-Ph), 112.3 (C-5), 54.6 (C-6), 15.2 (C-7). X-ray crystal
structure analysis of 4c: formula C13H13NTiCl2, M ) 302.04,
red crystal 0.25 × 0.15 × 0.10 mm, a ) 12.527(1) Å, b ) 13.747-
(1) Å, c ) 15.721(1) Å, V ) 2707.3(3) Å3, Fcalc ) 1.482 g cm-3
,
µ ) 10.03 cm-1, empirical absorption correction (0.788 e T e
0.906), Z ) 8, orthorhombic, space group Pbca (No. 61), λ )
0.71073 Å, T ) 198 K, ω and æ scans, 20 694 reflections
collected ((h, (k, (l)), [(sin θ)/λ] ) 0.66 Å-1, 3220 independent
(Rint ) 0.042) and 2649 observed reflections [I g 2σ(I)], 155
11 076 reflections collected ((h, (k, (l)), [(sin θ)/λ] ) 0.66 Å-1
,
2
3375 independent (Rint ) 0.061) and 3131 observed reflections
refined parameters, R ) 0.031, Rw ) 0.080, max. residual
[I g 2σ(I)], 174 refined parameters, R ) 0.031, Rw ) 0.079,
electron density 0.24 (-0.50) e Å-3, hydrogen atoms calculated
2
Flack parameter -0.01(3), max. residual electron density 0.21
(-0.42) e Å-3, hydrogen atoms calculated and refined as riding
atoms.
and refined as riding atoms.
Preparation of [η5:[1-(o-Methoxyphenylamido)-2,2-
dimethylpropyl]cyclopentadienyl-KN,O]dichlorozirco-
nium (5a). Bis(dimethylamido)[η5:[1-(o-methoxyphenylamido)-
2,2-dimethylpropyl]cyclopentadienyl-κN,O]zirconium (16a)
[prepared from 9a (4.17 g, 10.0 mmol) and ZrCl2(NMe2)2 (3.94
g, 10.0 mmol)] was dissolved in 40 mL of toluene. Then 10
mL of dichlorodimethylsilane (10.32 g, 80 mmol) was added
at -20 °C. The mixture was warmed to room temperature and
stirred for 1 h. The precipitated yellow powder was collected
by filtration and dried under vacuum (5a: 3.46 g, 8.3 mmol,
83%). The zirconium complex does not dissolve in any selected
Preparation of [η5:[1-(p-Methoxyphenylamido)ethyl]-
cyclopentadienyl-KN]dichlorotitanium (4b). After treat-
ment of bis(dimethylamido)[η5:[1-(p-methoxyphenylamido)-
ethyl]cyclopentadienyl-κN]titanium (15b) [prepared from 14b
(5.03 g, 15.0 mmol) and TiCl2(NMe2)2 (3.10 g, 15.0 mmol)] with
18 mL of dichlorodimethylsilane (18.58 g, 144 mmol) in 20 mL
of toluene at 50 °C for 4 h, the mixture was cooled slowly to
room temperature. Then 20 mL of pentane was added. The
dark red solution was stored at -30 °C overnight. The

C1-Bridged Cp/Amido Titanium and Zirconium Systems
Organometallics, Vol. 24, No. 20, 2005 4771
solvents (such as toluene, benzene, chloroform, dichloromethane)
without tetrahydrofuran. It could be that the zirconium
dichloride complex is a polymer with the chorines as bridges
between individual molecules. Anal. Calcd for C17H21Cl2NOZr
(417.5): C 48.91, H 5.07, N 3.36. Found: C 48.95, H 4.76, N
3.02. 1H NMR (499.8 MHz, d6-benzene/d8-tetrahydrofuran, 10:
1, 298 K): δ 6.90 (m, 1H, 11-H), 6.69 (m, 1H, 1-H), 6.67 (m,
1H, 10-H), 6.59 (m, 1H, 13-H), 6.54 (m, 1H, 12-H), 6.34 (m,
1H, 4-H), 6.25 (m, 1H, 2-H), 6.21 (m, 1H, 3-H), 4.78 (s, 1H,
6-H), 4.00 (s, 3H, 15-H), 1.17 (s, 9H, 8-H). 13C{1H} NMR (125.7
MHz, d6-benzene/d8-tetrahydrofuran, 10:1, 298 K): δ 151.1 (C-
14), 143.2 (C-9), 122.8 (C-11), 120.0 (C-4), 116.9 (C-12), 115.9
(C-1), 115.5 (C-5), 115.4 (C-3), 114.0 (C-2), 110.4 (C-10), 110.2
(C-13), 66.1 (C-6), 58.2 (C-15), 37.3 (C-7), 30.1 (C-8).
Synthesis of CpCN-Titanium or -Zirconium Dimethyl
Complexes. General Procedure. The CpCN titanium or
CpCN zirconium dichloride was dissolved in toluene (ca. 10
mL toluene/mmol dichloride) and cooled to -78 °C. MeMgCl
(3.0 M in THF, 2 molar equiv) was added. The mixture was
warmed slowly to room temperature. All volatiles were re-
moved under vacuum, and the residue was extracted with
pentane (20 mL), followed by filtration. After evaporation of
the solvent, normally a dark yellow oil or a brown solid was
obtained.
Preparation of [η5:[1-(Phenylamido)-2,2-dimethylpro-
pyl]cyclopentadienyl-KN]dimethyltitanium (17c). From
[η5:[1-(phenylamido)-2,2-dimethylpropyl)]cyclopentadienyl-κN]-
dichlorotitanium (3c) (344 mg, 1.0 mmol) and MeMgCl (3.0 M
in THF, 0.67 mL, 2.0 mmol), a dark yellow oil was obtained
(17c: 218 mg, 0.72 mmol, 72%). Anal. Calcd for C18H25NTi
(303.3): C 71.29, H 8.31, N 4.62. Found: C 71.46, H 8.16, N
4.05. 1H NMR (599.9 MHz, d6-benzene, 298 K): δ 7.28 (m, 2H,
o-Ph), 7.26 (m, 2H, m-Ph), 6.90 (m, 1H, p-Ph), 6.39 (m, 1H,
3-H), 6.37 (m, 1H, 2-H), 5.88 (m, 1H, 1-H), 5.59 (m, 1H, 4-H),
4.63 (s, 1H, 6-H), 0.92 (s, 3H, 9-H), 0.89 (s, 9H, 8-H), 0.29 (s,
3H, 10-H). 13C{1H} NMR (150.8 MHz, d6-benzene, 298 K): δ
151.9 (ipso-Ph), 130.0 (m-Ph), 122.7 (p-Ph), 121.8 (C-4), 119.5
(C-1), 118.2 (o-Ph), 115.6 (C-2), 115.4 (C-3), 104.4 (C-5), 67.0
(C-6), 57.8 (C-10), 47.5 (C-9), 37.1 (C-7), 28.0 (C-8).
Preparation of [η5:[1-(tert-Butylamido)-2,2-dimethyl-
propyl]cyclopentadienyl-KN]dimethyltitanium (17d).
From [η5:[1-(tert-butylamido)-2,2-dimethylpropyl)]cyclopenta-
dienyl-κN]dichlorotitanium (3d) (324 mg, 1.0 mmol) and
MeMgCl (3.0 M in THF, 0.67 mL, 2.0 mmol), a dark yellow oil
was obtained (17d: 229 mg, 0.81 mmol, 81%). Anal. Calcd for
C16H29NTi (283.3): C 67.84, H 10.32, N 4.94. Found: C 67.14,
1
H 9.98, N 4.80. H NMR (599.9 MHz, d6-benzene, 298 K): δ
6.47 (m, 1H, 3-H), 6.43 (m, 1H, 2-H), 5.61 (m, 1H, 1-H), 5.31
(m, 1H, 4-H), 4.04 (s, 1H, 6-H), 1.59 (s, 9H, 10-H), 1.02 (s, 9H,
8-H), 0.60 (s, 3H, 11-H), 0.27 (s, 3H, 12-H). 13C{1H} NMR
(150.8 MHz, d6-benzene, 298 K): δ 121.1 (C-4), 117.3 (C-1),
116.4 (C-3), 116.2 (C-2), 105.5 (C-5), 69.1 (C-6), 57.7 (C-9), 47.3
(C-12), 43.5 (C-11), 35.1 (C-7), 31.2 (C-10), 29.4 (C-8).
Preparation of [η5:[1-(o-Methoxyphenylamido)-2,2-
dimethylpropyl]cyclopentadienyl-KN,O]dimethyltitani-
um (17a). From [η5:[1-(o-methoxyphenylamido)-2,2-dimeth-
ylpropyl]cyclopentadienyl-κN,O]dichlorotitanium (3a) (630 mg,
1.5 mmol) and MeMgCl (3.0 M in THF, 1.0 mL, 3.0 mmol), a
yellow to brown powder of 17a (403 mg 1.2 mmol, 81%) was
obtained. Suitable X-ray crystals were obtained by slow
diffusion of pentane into a toluene solution of the dimethyl
complex at -30 °C. Anal. Calcd for C19H27NOTi (333.3): C
68.47, H 8.17, N 4.20. Found: C 68.28, H 7.88, N 4.13. 1H NMR
(499.8 MHz, d6-benzene, 298 K): δ 6.91 (m, 1H, 11-H), 6.74
(m, 1H, 3-H), 6.71 (m, 1H, 13-H), 6.60 (m, 2H, 10-H/12-H), 6.50
(m, 1H, 2-H), 5.88 (m, 1H, 1-H), 5.38 (m, 1H, 4-H), 4.32 (s,
1H, 6-H), 4.03 (s, 3H, 15-H), 1.03 (s, 9H, 8-H), 0.46 (s, 3H,
16-H), 0.03 (s, 3H, 17-H). 13C{1H} NMR (125.7 MHz, d6-
benzene, 298 K): δ 152.2 (C-14), 144.2 (C-9), 122.1 (C-11),
119.4 (C-3), 117.3 (C-4), 117.2 (C-2), 115.7 (C-12), 113.6 (C-1),
109.3 (C-13), 108.6 (C-10), 107.1 (C-5), 65.7 (C-6), 57.2 (C-15),
48.7 (C-17), 44.8 (C-16), 36.6 (C-7), 29.5 (C-8). X-ray crystal
structure analysis of 17a: formula C19H27NOTi, M ) 333.32,
yellow crystal 0.20 × 0.15 × 0.05 mm, a ) 9.197(1) Å, b )
11.255(1) Å, c ) 17.432(1) Å, R ) 79.97(1)°, â ) 87.83(1)°, γ )
Preparation of [η5:[1-(o-Methoxyphenylamido)ethyl]-
cyclopentadienyl-KN,O]dimethyltitanium (18a). From [η5:
[1-(o-methoxyphenylamido)ethyl]cyclopentadienyl-κN,O]dichlo-
rotitanium (4a) (498 mg, 1.5 mmol) and MeMgCl (3.0 M in
THF, 1.0 mL, 3.0 mmol), a yellow to brown powder of 18a (297
mg 1.0 mmol, 68%) was obtained. Suitable X-ray crystals were
obtained by slow diffusion of pentane into a toluene solution
of the dimethyl complex at -30 °C. Anal. Calcd for C16H21-
NOTi (291.2): C 65.99, H 7.27, N 4.81. Found: C 65.74, H
6.96, N 4.47. 1H NMR (499.8 MHz, d6-benzene, 298 K): δ 6.96
(m, 1H, 10-H), 6.74 (m, 1H, 12-H), 6.71 (m, 1H, 3-H), 6.67 (m,
1-H, 11-H), 6.63 (m, 1H, 2-H), 5.71 (m, 1H, 1-H), 5.45 (m, 1H,
3
4-H), 4.34 (q, JH-H ) 6.4 Hz, 1H, 6-H), 4.00 (s, 3H, 14-H),
3
1.17 (d, JH-H ) 6.4 Hz, 3H, 7-H), 0.29 (s, 3H, 15-H), 0.11 (s,
3H, 16-H). 13C{1H} NMR (125.7 MHz, d6-benzene, 298 K): δ
151.7 (C-13), 142.4 (C-8), 122.3 (C-10), 118.3 (C-3), 117.2 (C-
2), 115.8 (C-11), 115.4 (C-4), 112.1 (C-1), 108.9 (C-5), 108.8 (C-
12), 106.2 (C-9), 57.2 (C-14), 51.1 (C-6), 46.4 (C-16), 44.3 (C-
15), 16.4 (C-7). X-ray crystal structure analysis of 18a: formula
C16H21NOTi, M ) 291.24, yellow crystal 0.35 × 0.25 × 0.15
mm, a ) 8.889(1) Å, b ) 8.988(1) Å, c ) 10.515(1) Å, R )
111.86(1)°, â ) 94.71(1)°, γ ) 104.14(1)°, V ) 742.0(1) Å3, Fcalc
) 1.304 g cm-3, µ ) 5.69 cm-1, empirical absorption correction
(0.826 e T e 0.920), Z ) 2, triclinic, space group P1h (No. 2), λ
) 0.71073 Å, T ) 198 K, ω and æ scans, 7546 reflections
collected ((h, (k, (l), [(sin θ)/λ] ) 0.66 Å-1, 3506 independent
(Rint ) 0.044) and 3092 observed reflections [I g 2σ(I)], 176
86.50(1)°, V ) 1772.9(3) Å3, Fcalc ) 1.249 g cm-3, µ ) 4.85 cm-1
,
empirical absorption correction (0.909 e T e 0.976), Z ) 4,
triclinic, space group P1h (No. 2), λ ) 0.71073 Å, T ) 198 K, ω
and æ scans, 18 724 reflections collected ((h, (k, (l), [(sin θ)/
λ] ) 0.66 Å-1, 8441 independent (Rint ) 0.055) and 5678
observed reflections [I g 2σ(I)], 409 refined parameters, R )
0.051, Rw2 ) 0.119, max. residual electron density 0.31 (-0.38)
e Å-3, two almost identical molecules in the asymmetric unit,
hydrogen atoms calculated and refined as riding atoms.
Preparation of [η5:[1-(p-Methoxyphenylamido)-2,2-
dimethylpropyl]cyclopentadienyl-KN]dimethyltitani-
um (17b). From [η5:[1-(p-methoxyphenylamido)-2,2-dimeth-
ylpropyl]cyclopentadienyl-κN]dichlorotitanium (3b) (374 mg,
1.0 mmol) and MeMgCl (3.0 M in THF, 0.67 mL, 2.0 mmol), a
yellow to red oil of 17b (236 mg 0.71 mmol, 71%) was obtained.
Anal. C19H27NOTi (333.3): C 68.47, H 8.17, N 4.20. Found: C
2
refined parameters, R ) 0.038, Rw ) 0.104, max. residual
electron density 0.30 (-0.36) e Å-3, hydrogen atoms calculated
and refined as riding atoms.
Preparation of [η5:[1-(p-Methoxyphenylamido)ethyl]-
cyclopentadienyl-KN]dimethyltitanium (18b). From [η5:
[1-(p-methoxyphenylamido)ethyl]cyclopentadienyl-κN]dichlo-
rotitanium (4b) (0.5 equiv toluene adduct, 378 mg, 1.0 mmol)
and MeMgCl (3.0 M in THF, 0.67 mL, 2.0 mmol), a red powder
of 18b (186 mg 0.64 mmol, 64%) was obtained. Suitable X-ray
crystals could be obtained by slow diffusion of pentane into a
solution of the dimethyl complex in toluene at -30 °C. Anal.
Calcd for C16H21NOTi (291.2): C 65.99, H 7.27, N 4.81.
Found: C 65.46, H 7.30, N 4.78. 1H NMR (499.8 MHz,
d6-benzene, 298 K): δ 7.25 (m, 2H, 9-H), 6.87 (m, 2H, 10-H),
6.36 (m, 2H, 2-H/3-H), 5.77 (m, 1H, 1-H), 5.63 (m, 1H, 4-H),
1
68.49, H 8.08, N 3.88. H NMR (599.9 MHz, d6-benzene, 298
K): δ 7.11 (m, 2H, 10-H), 6.84 (m, 2H, 11-H), 6.39 (m, 1H,
3-H), 6.36 (m, 1H, 2-H), 5.86 (m, 1H, 1-H), 5.60 (m, 1H, 4-H),
4.55 (s, 1H, 6-H), 3.31 (s, 3H, 13-H), 0.87 (s, 9H, 8-H), 0.86 (s,
3H, 14-H), 0.25 (s, 3H, 15-H). 13C{1H} NMR (150.8 MHz, d6-
benzene, 298 K): δ 156.3 (C-12), 145.5 (C-9), 121.8 (C-4), 120.0
(C-10), 119.4 (C-1), 115.3 (C-11), 115.2 (C-2), 115.0 (C-3), 104.5
(C-5), 68.0 (C-6), 56.0 (C-15), 54.9 (C-13), 46.0 (C-14), 36.9 (C-
7), 27.9 (C-8).

4772 Organometallics, Vol. 24, No. 20, 2005
Wang et al.
3
4.69 (q, JHH ) 6.5 Hz, 1H, 6-H), 3.37 (s, 3H, 12-H), 1.13 (d,
oily product was dried in a vacuum (atom numbering of the
butadiene ligand used: 11-14 in complexes 21, 8-11 in the
complexes 22).
3JHH ) 6.5 Hz, 3H, 7-H), 0.84 (13-H), 0.58 (14-H). 13C{1H} NMR
(125.7 MHz, d6-benzene, 298 K): δ 154.9 (C-11), 145.0 (C-8),
120.0 (C-4), 117.5 (C-1), 115.2 (C-3), 115.1 (C-9), 114.8 (C-10),
114.7 (C-2), 106.3 (C-5), 57.4 (C-14), 54.9 (C-12), 52.0 (C-6),
49.7 (C-13), 15.6 (C-7). X-ray crystal structure analysis of
18b: formula C16H21NOTi, M ) 291.24, red crystal 0.20 × 0.20
× 0.15 mm, a ) 7.820(1) Å, b ) 11.577(1) Å, c ) 16.910(1) Å,
V ) 1530.9(3) Å3, Fcalc ) 1.264 g cm-3, µ ) 5.51 cm-1, empirical
absorption correction (0.898 e T e 0.922), Z ) 4, orthorhombic,
space group P212121 (No. 19), λ ) 0.71073 Å, T ) 198 K, ω
and æ scans, 12 189 reflections collected ((h, (k, (l), [(sin θ)/
λ] ) 0.66 Å-1, 3623 independent (Rint ) 0.063) and 2836
observed reflections [I g 2σ(I)], 176 refined parameters, R )
Preparation of [η5:[1-(o-Methoxyphenylamido)-2,2-
dimethylpropyl]cyclopentadienyl-KN](butadiene)tita-
nium (21a). From [η5:[1-(o-methoxyphenylamido)-2,2-dime-
thylpropyl]cyclopentadienyl-κN,O]dichlorotitanium (3a) (with
0.5 equiv toluene, 210 mg, 0.5 mmol) and butadiene magne-
sium THF complex (C4H6Mg‚2THF) (122 mg, 0.55 mmol), a
dark green to yellow oil of 21a (192 mg 0.61 mmol, 61%) was
dried in a vacuum. Anal. Calcd for C21H27NOTi (357.3): C
70.59, H 7.62, N 3.92. Found: C 71.53, H 7.65, N 3.73. 1H NMR
(499.8 MHz, d8-toluene, 298 K): δ 6.90 (ps, 1H, 1-H), 6.66 (m,
1H, 16-H), 6.60 (m, 1H, 4-H), 6.58 (m, 1H, 15-H), 6.34 (br, 1H,
14-H), 6.21 (m, 1H, 17-H), 5.76 (m, 1H, 10-H), 5.46 (ps, 1H,
2-H), 5.34 (ps, 1H, 3-H), 5.05 (s, 1H, 6-H), 4.95 (m, 1H, 11-H),
3.29 (m, 1H, 9syn-H), 3.07 (s, 3H, 19-H), 3.05 (m, 1H, 12syn-H),
1.00 (s, 9H, 8-H), 0.51 (m, 1H, 9anti-H), 0.36 (br, 1H, 12anti-H).
13C{1H} NMR (125.7 MHz, d8-toluene, 298 K): δ 151.0 (C-18),
142.5 (C-13), 126.4 (C-11), 124.0 (C-10), 123.3 (C-16), 120.6
(C-15), 113.8 (C-4), 111.0 (C-5), 110.2 (C-1/C-17), 109.5 (C-3),
108.3 (C-2), 73.5 (C-6), 64.2 (C-12), 63.6 (C-9), 55.0 (C-19), 36.4
(C-7), 28.0 (C-8).
2
0.042, Rw ) 0.099, Flack parameter 0.04(3), max. residual
electron density 0.31 (-0.31) e Å-3, hydrogen atoms calculated
and refined as riding atoms.
Preparation of [η5:[1-(Phenylamido)ethyl]cyclopen-
tadienyl-KN]dimethyltitanium (18c). From [η5:1-(N-phe-
nylamido)ethylcyclopentadienyl-κN]dichlorotitanium (4c) (302
mg, 1.0 mmol) and MeMgCl (3.0 M in THF, 0.67 mL, 2.0
mmol), a dark yellow oil was obtained (18c: 177 mg, 0.68
mmol, 68%). Anal. Calcd for C15H19NTi (261.2): C 68.98, H
7.33, N 5.36. Found: C 70.29, H 6.56, N 4.48. 1H NMR (599.9
MHz, d6-benzene, 298 K): δ 7.34 (m, 2H, o-Ph), 7.29 (m, 2H,
m-Ph), 6.86 (m, 1H, p-Ph), 6.35 (m, 2H, 2-H/3-H), 5.77 (m, 1H,
1-H), 5.60 (m, 1H, 4-H), 4.66 (q, 3JHH ) 6.6 Hz, 1H, 6-H), 1.12
(d, 3JHH ) 6.6 Hz, 3H, 7-H), 0.87 (s, 3H, 8-H), 0.62 (s, 3H, 9-H).
13C{1H} NMR (150.8 MHz, d6-benzene, 298 K): δ 150.6 (ipso-
Ph), 129.7 (m-Ph), 121.4 (p-Ph), 120.4 (C-4), 117.9 (C-1), 115.7
(C-3), 115.1 (C-2), 114.0 (o-Ph), 106.7 (C-5), 59.4 (C-9), 51.8
(C-6/C-8), 16.1 (C-7).
Preparation of [η5:[1-(p-Methoxyphenylamido)-2,2-
dimethylpropyl]cyclopentadienyl-KN](butadiene)tita-
nium (21b). From [η5:[1-(p-methoxyphenylamido)-2,2-dime-
thylpropyl]cyclopentadienyl-κN]dichlorotitanium (3b) (374 mg,
1.0 mmol) and butadiene magnesium THF complex (C4H6Mg‚
2THF) (244 mg, 1.1 mmol), a dark green to yellow oil of 21b
(239 mg 0.67 mmol, 67%) was obtained. Anal. Calcd for C21H27-
NOTi (357.3): C 70.59, H 7.62, N 3.92. Found: C 70.55, H
7.66, N 3.90. 1H NMR (599.9 MHz, d8-toluene, 193 K): δ 6.99
3
Preparation of [η5:[1-(o-Methoxyphenylamido)-2,2-
dimethylpropyl]cyclopentadienyl-KN]dimethylzirconi-
um (19a). From [η5:[1-(o-methoxyphenylamido)-2,2-dimeth-
ylpropyl]cyclopentadienyl-κN,O]dichlorozirconium (5a) (417
mg, 1.0 mmol) and MeMgCl (3.0 M in THF, 0.67 mL, 2.0
mmol), a yellow powder of 19a (304 mg 0.81 mmol, 81%) was
obtained. Suitable X-ray crystals were obtained by slow
diffusion of pentane to a toluene solution of the dimethyl
complex at -30 °C. Anal. Calcd for C19H27NOZr (376.7): C
60.59, H 7.23, N 3.72. Found: C 60.03, H 6.66, N 3.99. 1H NMR
(599.9 MHz, d6-benzene, 298 K): δ 6.93 (m, 1H, 11-H), 6.72
(m, 1H, 10-H), 6.49 (m, 2H, 12-H/13-H), 6.41 (m, 1H, 3-H), 6.21
(m, 1H, 2-H), 6.13 (m, 1H, 1-H), 5.55 (m, 1H, 4-H), 4.49 (s,
1H, 6-H), 3.81 (s, 3H, 15-H), 1.10 (s, 9H, 8-H), 0.09 (s, 3H,16-
H), -0.30 (s, 3H, 17-H). 13C{1H} NMR (150.8 MHz, d6-benzene,
298 K): δ ) 150.1 (C-14), 142.3 (C-9), 123.5 (C-11), 114.6 (C-
3), 114.4 (C-4), 114.2 (C-12), 111.8 (C-2), 111.0 (C-10), 110.4
(C-1), 109.3 (C-13), 109.1 (C-5), 65.3 (C-6), 57.8 (C-15), 36.9
(C-7), 32.3 (C-17), 30.3 (C-16), 29.6 (C-8). X-ray crystal
structure analysis of 19a: formula C19H27NOZr, M ) 376.64,
light yellow crystal 0.25 × 0.20 × 0.10 mm, a ) 9.409(1) Å, b
) 9.442(1) Å, c ) 11.747(1) Å, R ) 76.51(1)°, â ) 73.70(1)°, γ
) 65.31(1)°, V ) 902.0(2) Å3, Fcalc ) 1.387 g cm-3, µ ) 6.11
cm-1, empirical absorption correction (0.862 e T e 0.941), Z
) 2, triclinic, space group P1h (No. 2), λ ) 0.71073 Å, T ) 198
K, ω and æ scans, 9955 reflections collected ((h, (k, (l), [(sin
θ)/λ] ) 0.67 Å-1, 4380 independent (Rint ) 0.036) and 4158
observed reflections [I g 2σ(I)], 205 refined parameters, R )
0.024, Rw2 ) 0.067, max. residual electron density 0.37 (-0.55)
e Å-3, hydrogen atoms calculated and refined as riding atoms.
Synthesis of CpCN-Titanium Butadiene Complexes.
General Procedure. The CpCN titanium or CpCN zirconium
dichloride and 1.1 equiv of butadiene magnesium THF complex
(C4H6Mg‚2THF) were combined and cooled at -78 °C. Pre-
cooled toluene (10 mL of toluene/mmol dichloride) was added.
The mixture was warmed slowly to room temperature. Toluene
was removed, and the residue was taken up with pentane (20
mL of pentane/mmol dichloride). After filtration of lithium
chloride, pentane was removed and the remaining dark brown
(m, 1H, 1-H), 6.72 (m, 1H, 4-H), 6.54, 6.40 (each d, each JHH
) 8.0 Hz, each 1H, 14-H/18-H), 6.29 (m, 1H, 10-H), 6.11, 5.81
3
(each d, each JHH ) 8.0 Hz, each 1H, 15-H/17-H), 5.26 (m,
1H, 2-H), 5.15 (m, 1H, 11-H), 5.09 (ps, 1H, 3-H), 4.68 (s, 1H,
6-H), 3.67 (m, 1H, 9syn-H), 3.24 (m, 1H, 12syn-H), 3.17 (s, 3H,
19-H), 0.99 (s, 9H, 8-H), 0.43 (m, 1H, 9anti-H), -0.07 (m, 1H,
12anti-H). 13C{1H} NMR (150.8 MHz, d8-toluene, 193 K):
δ
154.9 (C-16), 147.7 (C-13), 125.3, 117.8 (C-15/C-17), 124.9 (C-
11), 124.1 (C-10), 113.4, 112.3 (C-14/C-18), 112.3 (C-4), 111.1
(C-1), 110.1 (C-5), 109.5 (C-3), 109.3 (C-2), 72.9 (C-6), 65.7 (C-
12), 63.3 (C-9), 54.2 (C-19), 36.7 (C-7), 27.9 (C-8).
Preparation of [η5:[1-(Phenylamido)-2,2-dimethylpro-
pyl]cyclopentadienyl-KN]-(butadiene)titanium (21c). From
[η5:[1-(N-phenylamido)-2,2-dimethylpropyl]cyclopentadienyl-
κN]dichlorotitanium (3c) (344 mg, 1.0 mmol) and butadiene
magnesium THF complex (C4H6Mg‚2THF) (244 mg, 1.1 mmol),
a dark brown oily product of 21c (214 mg 0.65 mmol, 65%)
was obtained. Anal. Calcd for C20H25NTi (327.3): C 73.40, H
7.70, N 4.28. Found: C 73.76, H 7.84, N 3.73. 1H NMR (499.8
MHz, d6-benzene, 298 K): δ 6.98 (m, 1H, 1-H), 6.90 (m, 2H,
m-Ph), 6.72 (m, 1H, p-Ph), 6.67 (m, 1H, 4-H), 6.20 (m, 2H,
o-Ph), 6.16 (m, 1H, 10-H), 5.39 (m, 1H, 2-H), 5.23 (m, 1H, 3-H),
4.98 (m, 1H, 11-H), 4.94 (s, 1H, 6-H), 3.57 (m, 1H, 9syn-H), 3.13
(m, 1H, 12syn-H), 0.96 (s, 9H, 8-H), 0.47 (m, 1H, 9anti-H), -0.03
(m, 1H, 12anti-H). 13C{1H} NMR (125.7 MHz, d6-benzene, 298
K): δ 154.7 (ipso-Ph), 128.1 (m-Ph), 125.9 (C-11), 125.1 (C-
10), 122.5 (p-Ph), 121.4 (o-Ph), 122.2 (C-4), 111.2 (C-1), 110.6
(C-5), 109.7 (C-2/C-3), 73.8 (C-6), 66.4 (C-12), 64.2 (C-9), 37.1
(C-7), 28.2 (C-8).
Preparation of [η5:[1-(tert-Butylamido)-2,2-dimethyl-
propyl]cyclopentadienyl-KN](butadiene)titanium (21d).
From [η5:[1-(tert-butylamido)-2,2-dimethylpropyl)]cyclopenta-
dienyl-κN]dichlorotitanium (3d) (324 mg, 1.0 mmol) and
butadiene magnesium THF complex (C4H6Mg‚2THF) (244 mg,
1.1 mmol), a dark brown oily product of 21d (167 mg 0.54
mmol, 54%) was obtained. Anal. Calcd for C18H29NTi (307.3):
1
C 70.35, H 9.51, N 4.56. Found: C 69.73, H 9.40, N 4.26. H
NMR (599.9 MHz, d6-benzene, 298 K): δ 6.51 (m, 1H, 4-H),
6.41 (m, 1H, 1-H), 6.31 (m, 1H, 13-H), 5.88 (m, 1H, 12-H), 5.78

C1-Bridged Cp/Amido Titanium and Zirconium Systems
Organometallics, Vol. 24, No. 20, 2005 4773
(m, 1H, 3-H), 4.95 (s, 1H, 6-H), 4.12 (m, 1H, 2-H), 3.67 (m,
1H, 14syn-H), 3.20 (m, 1H, 11syn-H), 1.15 (s, 9H, 8-H), 0.61 (s,
9H, 10-H), 0.28 (m,1H, 11anti-H), -0.20 (m, 1H, 14anti-H). 13C-
{1H} NMR (150.8 MHz, d6-benzene, 298 K): δ 129.9 (C-13),
116.6 (C-12), 122.5 (C-5), 110.7 (C-4), 109.4 (C-3), 108.2 (C-2),
105.5 (C-1), 70.6 (C-6), 66.2 (C-14), 64.2 (C-11), 62.5 (C-9), 35.2
(C-7), 31.2 (C-10), 30.2 (C-8).
minum (used as scavenger) were introduced into the autoclave
before catalysts (prepared by adding a solution of 1 equiv of
activator in 5 mL of 1,2-dichlorobenzene to a solution of
dimethyl complexes in 2 mL of 1,2-dichlorobenzene) were
loaded into the reservoir.
The polymerization reaction was stopped by terminating the
transfer of ethylene with the bpc controller and quenching with
20 mL of aqueous HCl in methanol (1:1 v/v). The precipitated
polyethylene was collected by filtration, washed subsequently
with HCl, water, and methanol, and dried at 80 °C in a vacuum
overnight to constant weight.
Catalytic Ethylene/1-Octene Copolymerization. A 1 L
Bu¨chi glass autoclave with a catalyst reservoir and magnetic
stirrer was evacuated and filled with argon three times before
it was charged with 30 mL of toluene, 50 mL of 1-octene, and
20 mL of 10% methylalumoxane in toluene. A precise amount
of catalyst was dissolved in 7 mL of toluene and then loaded
into the reservoir. The stirrer was started (600 rpm), and the
autoclave was thermostated at a certain temperature while
the solution was saturated with ethylene at 1 bar, which was
controlled by a bpc 1202 (Bu¨chi pressflow gas controller with
program ‘bls2’). After the solution was saturated with ethylene
(the line of consumption volume went flat), the catalyst
solution in the reservoir was introduced directly into the
autoclave.
When [Ph3C+][B(C6F5)4-] was used instead of MAO as
activator, 50 mL of toluene, 50 mL of 1-octene, and 0.5 mL of
triisobutylaluminum (used as scavenger) were introduced into
the autoclave before catalysts (prepared by adding a solution
of 1 equiv of activator in 5 mL of 1,2-dichlorobenzene to a
solution of dimethyl complexes in 2 mL of 1,2-dichlorobenzene)
were loaded into the reservoir.
Preparation of [η5:[1-(p-Methoxyphenylamido)ethyl]-
cyclopentadienyl-KN](butadiene)titanium (22b). From
[η5:[1-(p-methoxyphenylamido)ethyl]cyclopentadienyl-κN]dichlo-
rotitanium (4b) (0.5 equiv toluene adduct, 378 mg, 1.0 mmol)
and butadiene magnesium THF complex (C4H6Mg‚2THF) (244
mg, 1.1 mmol), a dark green to yellow oil of 22b (198 mg 0.63
mmol, 63%) was obtained. Anal. Calcd for C18H21NOTi
(315.2): C 68.58, H 6.71, N 4.44. Found: C 68.52, H 6.72, N
4.29. 1H NMR (599.9 MHz, d8-toluene, 298 K): δ 6.86 (m, 1H,
1-H), 6.67 (m, 1H, 4-H), 6.49 (m, 2H, 13-H), 6.20 (m, 1H, 9-H),
6.04 (m, 2H, 14-H), 5.56 (m, 1H, 2-H), 5.37 (m, 1H, 10-H), 5.25
3
(m, 1H, 3-H), 4.92 (q, JHH ) 6.5 Hz, 1H, 6-H), 3.48 (m, 1H,
8
syn-H), 3.28 (s, 3H, 16-H), 3.11 (m, 1H, 11syn-H), 1.19 (d, 3JHH
) 6.5 Hz, 3H, 7-H), 0.32 (m, 1H, 8anti-H), 0.07 (m, 1H, 11anti
-
H). 13C{1H} NMR (150.8 MHz, d8-toluene, 298 K): δ 155.4 (C-
15), 147.5 (C-12), 124.8 (C-9/C-10), 121.1 (C-14), 113.5 (C-13),
112.2 (C-5), 109.9 (C-4), 109.6 (C-3), 109.1 (C-1), 108.9 (C-2),
65.2 (C-11), 64.0 (C-8), 58.6 (C-6), 54.6 (C-16), 17.0 (C-7).
Preparation of [η5:[1-(Phenylamido)ethyl]cyclopen-
tadienyl-KN](butadiene)titanium (22c). From [η5:[1-(N-
phenylamido)ethyl]cyclopentadienyl-κN]dichlorotitanium (4c)
(302 mg, 1.0 mmol) and butadiene magnesium THF complex
(C4H6Mg‚2THF) (244 mg, 1.1 mmol), a gray oily product of 22c
(192 mg 0.67 mmol, 67%) was obtained. Anal. Calcd for C17H19-
NTi (285.2): C 71.59, H 6.71, N 4.91. Found: C 71.34, H 7.07,
1
N 4.41. H NMR (499.8 MHz, d6-benzene, 298 K): δ 6.97 (m,
2H, m-Ph), 6.91 (m, 1H, 1-H), 6.75 (m, 1H, p-Ph), 6.66 (m, 1H,
4-H), 6.34 (m, 1H, 9-H), 6.22 (m, 2H, o-Ph), 5.55 (m, 1H, 2-H),
5.44 (m, 1H, 10-H), 5.13 (m, 1H, 3-H), 5.09 (q, JHH ) 6.3 Hz,
The polymerization reaction was stopped by terminating the
transfer of ethylene with the bpc controller and quenching with
20 mL of aqueous HCl in methanol (1:1 v/v). The reaction
mixture was separated. The organic phase was washed with
aqueous HCl and water. The toluene solution was concentrated
by using a rotating evaporator, and then the residue was dried
at 80 °C in a vacuum overnight to constant weight.
3
1H, 6-H), 3.58 (m, 1H, 8syn-H), 3.12 (m, 1H, 11syn-H), 1.28 (d,
3JHH ) 6.3 Hz, 3H, 7-H), 0.35 (m, 1H, 8anti-H), 0.13 (m, 1H,
11anti-H). 13C{1H} NMR (125.7 MHz, d6-benzene, 298 K): δ
153.5 (ipso-Ph), 128.5 (m-Ph), 125.7 (C-9), 125.4 (C-10), 121.6
(p-Ph), 119.6 (o-Ph), 112.5 (C-5), 110.3 (C-3), 109.7 (C-4), 109.5
(C-1/C-2), 66.6 (C-11), 65.6 (C-8), 57.6 (C-6), 17.2 (C-7).
Catalytic Ethylene Polymerization. A 1 L Bu¨chi glass
autoclave with a catalyst reservoir and magnetic stirrer was
evacuated and filled with argon three times before it was
charged with 200 mL of toluene and 20 mL of 10% methyla-
lumoxane in toluene. A precise amount of catalyst was
dissolved in 7 mL of toluene and then loaded into the catalyst
reservoir. The stirrer was started (600 rpm) and the autoclave
was thermostated at a certain temperature while the solution
was saturated with ethylene at 2 bar, which was controlled
by bpc 1202 (Bu¨chi pressflow gas controller with program
‘bls2’). After the solution was saturated with ethylene (the line
of consumption volume went flat), the catalyst solution in the
reservoir was introduced directly into the autoclave.
Acknowledgment. Financial support from the Fonds
der Chemischen Industrie and the Deutsche Fors-
chungsgemeinschaft is gratefully acknowledged. C.W.
thanks the NRW Graduate School of Chemistry at the
Universita¨t Mu¨nster for a stipend.
Supporting Information Available: A more detailed
Experimental Section is provided, including further spectro-
scopic data of the organometallic compounds and additional
information about the polymerization experiments and ad-
ditional information about the X-ray crystal structure deter-
minations. This material is available free of charge via the
Internet at http://pubs.acs.org.
When Ph3C+B(C6F5)4- or B(C6F5)3 was used instead of MAO
as activator, 200 mL of toluene and 0.5 mL of triisobutylalu-
OM0505918