Pendent aminoalkyl-substituted monocyclopentadienyltitanium compounds and their polymerization behavior

Article abstract of DOI:10.1021/om980118c

A series of new aminoalkyl-substituted monocyclopentadienyltitanium trichloride compounds have been prepared that contain pyridyl (2-picolyl), diisopropylaminoethyl, dimethylaminoethyl, and phenylethyl ligands. Incorporation of these pendent ligands to corresponding (cyclopentadienyl)triisopropoxytitanium and (indenyl)triisopropoxytitanium complexes are also described. The utility of these complexes for the polymerization of ethylene, propylene and styrene has been investigated.

Full text of DOI:10.1021/om980118c

Organometallics 1998, 17, 3775-3783
3775
P en d en t Am in oa lk yl-Su bstitu ted
Mon ocyclop en ta d ien yltita n iu m Com p ou n d s a n d Th eir
P olym er iza tion Beh a vior
Matthew S. Blais, J ames C. W. Chien, and Marvin D. Rausch*
Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003
Received February 19, 1998
A series of new aminoalkyl-substituted monocyclopentadienyltitanium trichloride com-
pounds have been prepared that contain pyridyl (2-picolyl), diisopropylaminoethyl, di-
methylaminoethyl, and phenylethyl ligands. Incorporation of these pendent ligands to
corresponding (cyclopentadienyl)triisopropoxytitanium and (indenyl)triisopropoxytitanium
complexes are also described. The utility of these complexes for the polymerization of
ethylene, propylene and styrene has been investigated.
Ch a r t 1
In tr od u ction
With the discovery by Flores et al.1 of the pendent
aminoalkyl effect on organotitanium catalysts for the
polymerization of ethylene, propylene, and styrene,
considerable effort in our laboratory and elsewhere has
been focused on the development of new, more active,
and more stable catalyst systems of this type.
Qichen et al.2 reported the first example of a chelated
cyclopentadienyl ligand on a titanium half-sandwich
complex. Their synthesis and X-ray structural deter-
mination of [η5-(2-methoxyethyl)cyclopentadienyl]tri-
chlorotitanium (1) demonstrated that the ether oxygen
atom in the side chain attached to the cyclopentadienyl
ring coordinates with the titanium atom to form a
chelate ring (Chart 1). They also noted that 1 was
considerably more sensitive to moisture and was ther-
mally less stable than CpTiCl3. Flores et al. developed
the catalyst precursors [η5-(2-dimethylaminoethyl)cy-
clopentadienyl]trichlorotitanium (2)1 and [η5-2,3,4,5-
tetramethyl-1-(2-dimethylaminoethyl)cyclopentadienyl]-
trichlorotitanium (3).3 They demonstrated that 2 was
approximately 100 times as active for the polymeriza-
tion of ethylene as CpTiCl3 and that both 2 and 3 were
efficient catalyst precursors for the polymerization of
propylene, giving atactic polymer of high molecular
weight.
Recently, Herrmann et al.4 reported the pyrrolidine
and piperidine analogues of 1, confirming Ti-N in-
tramolecular coordination for the former (4) by an X-ray
diffraction study. J utzi and Kleimeier5 also recently
described the synthesis and molecular structure of the
first zirconium analogue (5) containing a pendent ami-
noalkylcyclopentadienyl system. Their studies demon-
strated direct coordination of the amino nitrogen to the
zirconium center. They also prepared the tris(dimethy-
lamido)titanium analogue (6).
In this paper, we report the synthesis of some
analogues of 1 that contain bridged pyridyl (2-picolyl),
diisopropylaminoethyl, and phenylethyl ligands. Exten-
sions of these pendent ligands to corresponding (cyclo-
pentadienyl)triisopropoxytitanium and (indenyl)triiso-
propoxytitanium complexes are described. The utility
of these complexes for the polymerization of ethylene,
propylene, and styrene is also discussed.
Resu lts a n d Discu ssion
Syn th esis of P en d en t Liga n d s. All organic ligands
used in the present study were prepared by modifica-
tions of the procedures described by Wang et al.6 and
Flores et al.1 Reactions between cyclopentadienylso-
dium and 2-picolyl chloride, 2-dimethylaminoethyl chlo-
ride, and 2-bromoethylbenzene in THF solution pro-
duced (2-picolyl)cyclopentadiene (7), (2-dimethylamino-
ethyl)cyclopentadiene (8), and (2-phenylethyl)cyclopen-
tadiene (9), respectively, in 67-78% yield. A similar
(1) Flores, J . C.; Chien, J . C. W.; Rausch, M. D. Organometallics
1994, 13, 4140.
(2) Qichen, H.; Yanlong, Q.; Guisheng, L. Transition Met. Chem.
1990, 15, 483.
(3) Flores, J . C.; Chien, J . C. W.; Rausch, M. D. Macromolecules
1996, 29, 8030.
(4) Herrmann, W. A.; Morawietz, M. J . A.; Priermeier, T. S.;
Mashima, K. J . Organomet. Chem. 1995, 486, 291.
(5) J utzi, P.; Kleimeier, J . J . Organomet. Chem. 1995, 486, 287.
(6) Wang, T.-F.; Lee, T.-Y.; Chou, J .-W.; Ong, C.-W. J . Organomet.
Chem. 1992, 423, 31.
S0276-7333(98)00118-6 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 07/21/1998

3776 Organometallics, Vol. 17, No. 17, 1998
Blais et al.
Sch em e 1
can be readily distilled under vacuum to give elemen-
tally pure samples. The tarlike materials observed in
the purification of the aminoalkylcyclopentadienes were
not observed in distillations of the substituted indenes
if the crude products were heated gently in an oil bath
with good temperature control.
New Cyclop en ta d ien ylth a lliu m Rea gen ts Con -
ta in in g P en d en t Liga n d s. During this study, three
new substituted cyclopentadienylthallium reagents (14-
16) were synthesized in excellent yield. Their utility
as intermediates in reactions with both early and late
organotransition metal halides was also demonstrated
(Scheme 2).
Many mono- and persubstituted cyclopentadienyl-
thallium compounds are reported in the literature, and
their utility as synthetic intermediates makes them
highly useful reagents.7 Their relative stability and
their ease of purification by vacuum sublimation are in
contrast to analogous organosodium and organolithium
reagents.
Reaction of 7 with 1 equiv of thallium ethoxide
produced (2-picolyl)cyclopentadienylthallium (14) in
87% yield as a white solid that slowly darkened in the
light at room temperature. Vacuum sublimation of the
darkened material gave a white crystalline sublimate,
which was used in a subsequent reaction with chlorodi-
carbonylrhodium dimer to form [η5-(2-picolyl)cyclopen-
tadienyl]dicarbonylrhodium (17) in 69% yield (Scheme
2). Vacuum distillation of 17 gave a sample of elemental
purity but also resulted in some decomposition. Com-
pound 17 is very hygroscopic and darkens on exposure
to air.
A reaction between 8 and thallium ethoxide produced
(2-dimethylaminoethyl)cyclopentadienylthallium (15) in
97% yield. The product could be vacuum sublimed to
afford 15 as a white crystalline solid that was of
elemental purity but was best stored at -15 °C under
argon and in the dark. Reaction of 15 with chlorodi-
carbonyl(pyridine)iridium gave [η5-(2-dimethylamino-
ethyl)cyclopentadienyl]dicarbonyliridium (18) in higher
yield (76%) than was obtained from the corresponding
organolithium reagent (45%).8
reaction in THF solution between 2-diisopropylamino-
ethyl chloride and cyclopentadienyllithium afforded (2-
diisopropylaminoethyl)cyclopentadiene (10) in 46% yield.
Analogous reactions between indenyllithium and 2-di-
methylaminoethyl chloride, 2-diisopropylaminoethyl chlo-
ride, and 2-pyridylethyl chloride formed 3-(2-dimethyl-
aminoethyl)indene (11), 3-(2-diisopropylaminoethyl)-
indene (12), and 3-(2-pyridylethyl)indene (13) in yields
of 50-95%, respectively. All pendent ligand compounds
were purified by vacuum distillation and were charac-
terized by elemental analyses as well as by their 1H
NMR spectra. Scheme 1 illustrates the syntheses of all
the pendent ligands.
Two basic methods were used to generate the free
chloroalkylamines from their respective hydrochlorides.
In most cases, the amine was generated by reaction with
an aqueous solution of potassium hydroxide, followed
by extraction with hexane and benzene. Separation and
drying of the organic layer over magnesium sulfate gave
excellent results. In the case of several indenyllithium
reactions, 2 equiv of the organolithium compound was
used, and the amino reactant was added as the hydro-
chloride. The first equivalent was used as a base to
convert the hydrochloride to the amine, and the second
equivalent was used as a nucleophile, displacing the
halide and generating the desired ligand.
(2-Phenylethyl)cyclopentadienylthallium (16) was ob-
tained in 78% yield from a reaction between thallium
ethoxide and 9, followed by vacuum sublimation of the
product. It was necessary to extract the crude product
repeatedly with pentane before sublimation in order to
remove a small amount of excess 9 which otherwise
distilled with the desired product. Reactions of 16 with
chlorodicarbonylrhodium dimer and with (η5-penta-
All the aminoalkylcyclopentadienes generated in this
study are thermally sensitive compounds. Vacuum
distillation of the crude products in order to obtain pure
ligands always gave red or dark orange tarlike residues.
However, trapping the distilled product at dry ice
temperatues allowed for long-term storage of the puri-
fied ligands without appreciable loss due to side reac-
tions. Conversion to corresponding lithium cyclopen-
tadienides and subsequent conversion to respective
trimethylsilyl derivatives represents another means of
trapping the distilled ligands.
(7) See, for example: (a) Rausch, M. D.; Edwards, B. H.; Rogers, R,
D.; Atwood, J . L. J . Am. Chem. Soc. 1983, 105, 3882. (b) Conway, B.
G.; Rausch, M. D. Organometallics 1985, 4, 688. (c) Gassman, P. G.;
Winter, C. H. J . Am. Chem. Soc. 1986, 108, 4228. (d) Werner, H.; Otto,
H.; Kraus, H. J . J . Organomet. Chem. 1986, 315, C57. (e) Spink, W.
C.; Rausch, M. D. J . Organomet. Chem. 1986, 308, C1. (f) Schumann,
H.; J aniak, C.; Khani, H. J . Organomet. Chem. 1987, 330, 347. (g)
Arthurs, M.; Al-Daffaee, H. K.; Haslop, J .; Kubal, G.; Pearson, M. D.;
Thatcher, P.; Curzon, E. J . Chem. Soc., Dalton Trans. 1987, 2615. (h)
Singh, P.; Rausch, M. D.; Bitterwolf, T. E. J . Organomet. Chem. 1988,
352, 273. (i) Rausch, M. D.; Lewison, J . F.; Hart, W. P. J . Organomet.
Chem. 1988, 358, 161. (j) Rausch, M. D.; Spink, W. C.; Atwood, J . L.;
Baskar, A. J .; Bott, S. G. Organometallics 1989, 8, 2627. (k) J ones, S.
S.; Rausch, M. D.; Bitterwolf, T. E. J . Organomet. Chem. 1990, 396,
279. (l) Schumann, H.; Ghodsi, T.; Esser, L.; Hahn, E. Chem. Ber. 1993,
126, 591. (m) J ones, S. S.; Rausch, M. D.; Bitterwolf, T. E. J .
Organomet. Chem. 1993, 450, 27.
Indenyllithium reacted with the chloroalkylamines to
give the desired aminoalkylindenes in high yield (Scheme
l). These ligands are stable at room temperature and
(8) Blais, M. S.; Rausch, M. D. J . Organomet. Chem. 1995, 502, 1.

Pendent Aminoalkyl-Substituted CpTi Compounds
Organometallics, Vol. 17, No. 17, 1998 3777
Sch em e 2
Sch em e 3
titanium tetrachloride. However, using an approach
employed by Shaw et al.9 for monoindenyl trichloride
derivatives of zirconium and hafnium, we were able to
convert the indenyl ligand 11 to the tributyltin deriva-
tive 25 and subsequently into 26 (Scheme 4). The
product was very air sensitive and could not be obtained
in elemental purity. However, the reaction product was
pure by NMR and proved to be an excellent catalyst for
the polymerization of ethylene and propylene (see
Polymerization Studies section).
In addition to pendent aminoalkyl-substituted sys-
tems, Flores et al.10 synthesized [1-(2-phenylethyl)-
2,3,4,5-tetramethylcyclopentadienyl]trichlorotitanium and
determined that it was a good catalyst for the polym-
erization of both ethylene and styrene. For this reason,
we also synthesized [η5-(2-phenylethyl)cyclopentadienyl]-
trichlorotitanium (28) from ligand 9 via the trimethyl-
silyl intermediate 27 (Scheme 4). The ligand 9 under-
goes dimerization fairly rapidly, and an intractible tarry
residue was formed during vacuum distillation. The
ligand is best converted to either the trimethylsilyl
derivative 27 or the thallium complex 16 for prolonged
storage.
methylcyclopentadienyl)trichlorotitanium gave the de-
sired products (19, 20) in good yields.
Ca ta lyst P r ecu r sor Syn th esis. Initial studies were
directed toward the synthesis and characterization of
pendent [(aminoalkyl)cyclopentadienyl]trichlorotitanium
compounds using the ligands described above. Com-
pound 2 was prepared in high yield via the trimethyl-
silyl intermediate 21 by a modification of the original
literature procedure (Scheme 3).1 In the 2-picolyl
system, ligand 7 was sucessfully converted into the
corresponding trimethylsilyl intermediate 22 in 92%
yield. However, in subsequent reactions of 22 with
titanium tetrachloride under a variety of conditions, we
were not able to isolate the desired trichloride 23 but
obtained instead the µ-oxo dimer dihydrochloride 24
(Scheme 3). The extreme moisture sensitivity of 23 is
derived from the fact that the pyridyl group in 23 can
act as a driving force to facilitate its hydrolysis to form
24, as has been observed previously for 2. We were
subsequently able to prepare 23 in 83% yield from a
reaction between thallium reagent 14 and titanium
tetrachloride in toluene; however, the compound could
not be obtained in analytical purity due to its high
sensitivity.
The extraordinarily high sensitivity of aminoalkyl-
substituted cyclopentadienyltitanium trichlorides such
as 23 and 26 prompted us to develop catalyst precursor
systems that were more stable to hydrolysis. The use
of chlorotitanium triisopropoxide to form analogous
titanium triisopropoxide derivatives has several advan-
tages.11 First, the reaction products were much more
Several attempts to prepare [η5-1-(2-dimethylamino-
ethyl)indenyl]trichlorotitanium (26) via a trimethylsilyl
intermediate were unsuccessful. The reaction product
appeared via NMR to be an amine coordination complex
between the amino ligand of the silyl intermediate and
(9) Shaw, S. L.; Morris, R. J .; Huffman, J . C. J . Organomet. Chem.
1995, 489, C4.
(10) Flores, J . C.; Wood, J . S.; Chien, J . C. W.; Rausch, M. D.
Organometallics 1996, 15, 4944.

3778 Organometallics, Vol. 17, No. 17, 1998
Blais et al.
Sch em e 4
Sch em e 6
Ta ble 1. P olym er iza tion Da ta for Ca ta lyst
P r ecu r sor s 26 a n d 32 (50 µM)
Tp
time polymer activity
(h)
yield (g) (10-6
Mw
Tm
(°C)
catalyst monomer (°C)
)
(10-5
)
26
26
26
32
32
ethylene
propylene 21 1.0
styrene
ethylene
21 0.167 1.41
9.1
0.12
0.017
4.1
0.32
0.72 135.5
1.8
1.21
21 1.0
22 0.5
0.00367
1.986
3.20
3.7
4.3
133.9
propylene 22 6.0
pentadienyl]triisopropoxytitanium (29) could be vacuum
distilled in elemental purity before thermal decomposi-
tion occurred. Compounds 30 and 31 decomposed before
distillation; however, the crude products were pure
enough for catalysis, and both gave polyethylene and
polypropylene when used in olefin polymerizations (see
Polymerization Studies).
Three other catalyst precursors (32-34) were also
prepared in the indenyl system using isopropoxide
ancillary ligands. Scheme 6 illustrates the synthesis
of these compounds. The isopropoxides 32-34 were all
much more resistant to hydrolysis than any of the
corresponding aminoalkyl-substituted cyclopentadie-
nyltitanium trichlorides described above. They were
obtained as orange-red high-boiling oils and were char-
Sch em e 5
1
acterized by H NMR spectra. All attempts at further
purification were not successful.
P olym er iza tion Stu d ies. The pendent ligand cata-
lyst precursors synthesized for this study were all
activated using methylaluminoxane (MAO) as a cocata-
lyst. The individual catalysts were run under various
polymerization conditions. Temperature, monomer,
catalyst concentration, and cocatalyst concentration
were varied in an attempt to optimize the polymeriza-
tion results. Activity (A) was calculated as a function
of grams of polymer produced per hour per mole of
catalyst per concentration of monomer (moles for liquid
monomers). Molecular weights (Mw) were determined
by viscosity measurements, and melting temperatures
(Tm) were determined by differential scanning calorim-
etry.
stable to hydrolysis and could, therefore, be handled
with greater ease. Second, the solubilities of the
catalyst precursors were much greater due to the
isopropoxide ligands. The synthesis of triisopropoxide
derivatives was also more straightforward since there
was no need to form trimethylsilyl analogues of the
ligands. Both organolithium and -thallium intermedi-
ates proved to be useful as starting materials for a series
of aminoalkyl-substituted cyclopentadienyltitanium tri-
isopropoxides (29-31), as shown in Scheme 5.
The major drawback to these triisopropoxide catalyst
precursors was the difficulty in purifying them, since
they are thermally sensitive and have very high boiling
points. Indeed, only [η5-(2-dimethylaminoethyl)cyclo-
High ethylene polymerization activity was obtained
for [(dimethylaminoethyl)indenyl]trichlorotitanium (26)
(A ) 9 × 106). The polyethylene (PE) produced has low
Mw (7.2 × 104) but good Tm (135.3 °C). Table 1
summarizes the polymerization data for catalyst 26. It
is extremely sensitive toward the environment, includ-
ing moisture, oxygen, heat, and light. Precursor 26 was
a relatively poor catalyst for propylene, with A ) 1.2 ×
105 and Mw ) 1.8 × 105. It was even less active for
styrene polymerization (A ) 1.7 × 104).
[(Dimethylaminoethyl)indenyl]triisopropoxytitan-
ium (32) was also a good catalyst for ethylene polym-
erization, giving polymerization activity comparable to
that reported for 2 by Flores et al.1 to produce PE of
(11) (a) Kucht, A.; Kucht, H.; Barry, S.; Chien, J . C. W.; Rausch, M.
D. Organometallics 1993, 12, 3075. (b) Barry, S.; Kucht, A.; Kucht,
H.; Rausch, M. D. J . Organomet. Chem. 1995, 489, 195.

Pendent Aminoalkyl-Substituted CpTi Compounds
Organometallics, Vol. 17, No. 17, 1998 3779
Ta ble 2. P olym er iza tion Da ta for Ca ta lyst
Ta ble 4. P olym er iza tion Da ta for Ca ta lyst
P r ecu r sor s 28 a n d 35
P r ecu r sor s 33 a n d 34 (50 µM)
Tp time polymer activity Mw
Tm
catalyst
catalyst
monomer
ethylene
(°C) (h) yield (g) (10-6
)
(10-5
)
(°C)
concn
Tp time polymer activity
Al/Ti monomer (°C) (h) yield (g) (10-6
catalyst
(µM)
)
33
33
33
34
34
21 3.5
21 3.5
0.72
0
0.22
0
0.88 134.8
28
28
28
28
28
35
35
35
50
1
1
50
50
50
50
50
4000/1 ethylene
20000/1 ethylene
20000/1 ethylene
4000/1 styrene
4000/1 styrene
4000/1 ethylene
4000/1 ethylene
4000/1 styrene
20 1.0
20 1.0
50 1.0
20 0.67 0.2128
50 1.0 1.541
20 0.08 0.290
50 0.08 0.147
50 1.0
0.0388
0.0066
0.0185
0.047
0.41
1.7
2.6
12.8
3.75
2.56
4.06
propylene
ethylene/hexene 21 3.5
0.44
0.31
trace
0.43
0.056
0
ethylene
propylene
21 6.0
21 6.0
3.5
135.2
Ta ble 3. P olym er iza tion Da ta for Ca ta lyst
P r ecu r sor s 24, 29, 30, a n d 31 (50 µM)
0.441
Tp
time polymer activity
Mw
catalyst monomer (°C)
(h)
yield (g)
(l0-6
)
(10-5
)
the isopropyl groups on the nitrogen and the titanium
center, partially blocking a coodination site on the
titanium and inhibiting chain propagation.
24
24
31
31
29
29
30
30
ethylene
ethylene
ethylene
styrene
ethylene
propylene
ethylene
propylene
0
20
75
75
50
50
25
25
1.0
1.0
4.0
12
0.25
1.0
0.52
0.90
3.02
0.068
0.33
0.16
0.89
0.22
0.74
1.5
2.9
0.0025
1.8
0.19
6.4
6.8
The even lower activity of 34 as a catalyst precursor
was surprising. The reactivity of the other pendent
pyridyl systems (24 and 31) would lead to the conclusion
that 34 would be a good catalyst precursor. The
difference between 34 and the other pyridyl systems is
the length of the bridge between the nitrogen atom and
the η5-cyclopentadienyl ring. All of the highly active
systems have two carbons between the nitrogen and the
ring. In 34, there are three carbons bridging the
nitrogen and the ring. The extra torsional energy in
the bridge and the changes in geometry of the nitrogen
coordination to the titanium probably account for the
decrease in catalytic activity of 34.
0.22
2.0
0.81
1.0
5.0
0.96
0.027
higher Mw but lower Tm. It has a slightly better activity
for propylene than 26, giving polymer of molecular
weight similar to that of 2. The glass transition
temperature and 13C NMR spectrum of the polypropy-
lene are consistent with atactic polymer, as expected.
There was a long induction period for catalyst precur-
sor 32 if it and the cocatalyst MAO were introduced
separately. Apparently their reaction is slow in dilute
concentration and in the presence of olefin. We found
that the induction period could be eliminated and
reasonable activities obtained with the isopropoxy-
substituted catalyst precursor by preactivation of 32
with 2000 equiv of MAO. Typically, the catalyst precur-
sor was dissolved in toluene, MAO was added, and the
solution was stirred for 30 min. The major advantage
of 32 was its enhanced stability and increased solubility.
Both [1-(2-diisopropylaminoethyl)indenyl]triisopro-
poxytitanium (33) and [1-(2-pyridylethyl)indenyl]triiso-
propoxytitanium (34) were an order of magnitude less
reactive than 2 in the polymerization of ethylene. They
were inactive toward propylene. Table 2 summarizes
the polymerization data.
[(2-Picolyl)cyclopentadienyl]dichlorotitanium µ-oxo
dimer dihydrochloride (24), [(2-picolyl)cyclopentadienyl]-
triisopropoxytitanium (31), [(2-dimethylaminoethyl)-
cyclopentadienyl]triisopropoxytitanium (29) and [(2-di-
isopropylaminoethyl)cyclopentadienyl]triisopropoxytitan-
ium (30) were all preactivated with 2000 equiv of MAO
for 30 min prior to injection. All of the catalyst
precursors gave activities similar to that of 2 except for
30, which was considerably lower. This is consistent
with the data obtained for the indenyl systems (vide
supra), where the diisopropylaminoethyl substituent
gave very poor activities. Table 3 gives a summary of
the polymerization data for these catalyst precursors.
Some definite trends were noted in the polymerization
behavior of the pendent amino-substituted half-sand-
wich titanium catalyst precursors. The steric bulk of
the diisopropylaminoethyl systems 30 and 33 definitely
decreases the catalytic activity toward both ethylene
and propylene compared to their dimethylaminoethyl
counterparts 29 and 32, respectively. There was also
a significant reduction in polymer molecular weights.
These two factors may indicate an interaction between
The last catalyst precursor examined was [(2-phenyl-
ethyl)cyclopentadienyl]trichlorotitanium (28). Flores et
al.14 found that [1-(2-phenylethyl)-2,3,4,5-tetramethyl-
cyclopentadienyl]trichlorotitanium (35) was an efficient
catalyst for both ethylene and styrene. For this reason,
we had high hopes for the catalytic activity of 28. In a
previous study, Flores et al.3 had discovered that the
pendent (2-dimethylaminoethyl)cyclopentadienyl sys-
tem (2) was an order of magnitude better than the (2-
dimethylaminoethyl)tetramethylcyclopentadienyl sys-
tem (3). Table 4 shows a comparison of the catalytic
properties of 28 and 35.
The pendent ligand appears to have an effect on
precursor 35, as seen in the enhanced ethylene polym-
erization activity for 35. This system also still shows
an appreciable polymerization activity for styrene. The
activities for styrene and ethylene are similar under the
conditions of 50 °C and 4000/1 MAO-to-precursor ratio.
This brings up the interesting possibility of copolymer-
ization of ethylene and styrene using such a system. The
poor polymerization activity of 28 relative to that of
ethylene is surprising based on previous expectations.
Precursor 28 behaves strictly like a nonpendent sub-
stituted cyclopentadienyltrichlorotitanium, giving excel-
lent polymerization activity toward styrene, poor activ-
ity toward ethylene, and no activity toward propylene.
This suggests the absence of bonding interaction be-
tween the pendent phenyl group and titanium.
(12) (a) Ready, T. E.; Day, R. O.; Chien, J . C. W.; Rausch, M. D.
Macromolecules 1993, 26, 5822.
(13) (a) Llinas, G. H.; Dong, S.-H.; Mallin, D. T.; Rausch, M. D.; Lin,
Y.-G.; Winter, H.H.; Chien, J . C. W. Macromolecules 1992, 25, 1242.
(b) Tsai, W.-M.; Rausch, M. D.; Chien, J . C. W. Appl. Organomet. Chem.
1993, 7, 71.
(14) Flores, J . C.; Wood, J . S.; Chien, J . C. W.; Rausch, M. D.
Organometallics 1996, 15, 4944.

3780 Organometallics, Vol. 17, No. 17, 1998
Blais et al.
6.47-6.06 (m, 3 H, vinylic C5H5), 2.96-2.90 (m, 2 H, sp3 C5H5),
2.50 (m, 4 H, CH2CH2), 2.26 (bs, 6 H, NCH3).
Exp er im en ta l Section
All operations were performed under an argon atmosphere
using Schlenk and glovebox techniques. Argon was deoxy-
genated by BASF catalyst and dried with P2O5 and molecular
sieves. Methylaluminoxane (MAO) was purchased from Akzo.
All other chemicals were obtained from Aldrich unless other-
wise stated. Reaction solvents were purified by distillation
from sodium-potassium alloy under argon, except for dichlo-
romethane which was distilled under argon from calcium
hydride. Styrene was purified by distllation from calcium
hydride under reduced pressure and stored at -25 °C under
argon in the dark. Infrared spectra were recorded on a Perkin-
Elmer 1600 FTIR in CH2Cl2 using subtraction techniques to
remove solvent signals. GCMS were recorded on a Perkin-
(2-P h en yleth yl)cyclop en ta d ien e (9). Cyclopentadienyl-
sodium (55.63 mmol) was prepared by reacting 1.335 g (55.63
mmol) of NaH with 3.68 g (55.7 mmol) of freshly cracked
cyclopentadiene in 100 mL of THF. The solution was allowed
to stir until gas evolution ceased and the sodium hydride was
consumed. To this solution, 10.295 g (55.63 mmol) of (2-
bromoethyl)benzene was added dropwise. The addition must
be done slowly because of the exothermic nature of the
reaction. After the addition was complete, the reaction
mixture was allowed to stir at room temperature for 1 h. The
mixture was then hydrolyzed with aqueous ammonium chlo-
ride (50 mL), and the layers were separated. The aqueous
layer was extracted with 50 mL of hexane, and the organic
portions were combined and dried over magnesium sulfate.
After filtration, the solvent was removed by rotary evaporation.
The resulting oil was vacuum distilled, with the fraction boiling
boiling between 91 and 93 °C collected as the main fraction
(6.80 g, 71% yield). 1H NMR (CDCl3, 200 MHz): δ 7.33-7.18
(m, 5 H, aromatic), 6.45-6.04 (m, 3 H, vinylic), 2.96-2.64 (m,
6 H, CH2CH2 and sp3 of C5 ring). Anal. Calcd for C13H14: C,
91.71; H, 8.29. Found: C, 91.65; H, 8.39.
1
Elmer HP 5970A gas chromatograph-mass spectrometer. H
and 13C NMR spectra were recorded on IBM NR-80 or Brucker
AC200 spectrometers. Elemental analyses were performed by
the University of Massachusetts Microanalytical Laboratory.
Note: Thallium and its compounds are extraordinarily toxic
and must be handled with appropriate safety precautions.
Suitable protective gloves should always be worn when han-
dling these materials.
(2-Diisop r op yla m in oeth yl)cyclop en ta d ien e (10). Cy-
clopentadienyllithium (75.2 mmol) was prepared from 5.04 g
(76.6 mmol) of freshly cracked cyclopentadiene and 47.9 mL
of 1.6 M n-BuLi (76.6 mmol) in 100 mL of THF at 0 °C, and
the solution was allowed to warm to room temperature. (2-
Chloroethyl)diisopropylamine hydrochloride (15.1 g, 75.2 mmol)
was dissolved in 100 mL of 2 N aqueous NaOH and extracted
with two 25-mL portions of hexane. The hexane fractions were
combined and dried with magnesium sulfate. After filtration,
this solution was added dropwise to the THF solution of
cyclopentadienyllithium, and the resulting brown solution was
refluxed for 4 h. After the brown suspension was allowed to
cool to room temperature, 50 mL of H2O was added, and after
the solution was stirred for 5 min, the layers were separated.
The solvent was removed under vacuum at room temperature,
and the brown oil was vacuum distilled to give an orange oil
(6.64 g, 45.7% yield) boiling at 64-68 °C and 0.5 mmHg. A
second distillation produced an elementally pure sample. 1H
NMR (CDCl3): δ (6.43-6.03 (m, 3 H, vinylic), 3.23-2.93 (m, 4
H, NCH(CH3)2 and sp3 of C5 ring), 2.56 (bs, 4 H, CH2CH2),
1.03 (d, 12 H, CH(CH3)2). Anal. Calcd for C13H23N: C, 80.76;
H, 11.99; N, 7.24. Found: C, 80.47; H, 11.94, N, 7.02.
(2-P icolyl)cyclop en ta d ien e (7). An aqueous solution of
5.00 g (89.1 mmol) of KOH in 40 mL of H2O was prepared
and cooled to 0 °C in an ice bath. To the cooled solution was
added 10.34 g (63.0 mmol) of 2-picolyl chloride hydrochloride,
and the solution was extracted two times with 40 mL of
benzene. The benzene layers were combined and dried over
magnesium sulfate. The benzene solution was transferred via
cannula to a solution of 66.7 mmol of cyclopentadienylsodium
in 100 mL of THF (prepared by reacting 1.60 g (66.7 mmol) of
NaH with 4.41 g (66.7 mmol) of freshly cracked cyclopentadi-
ene in 100 mL of THF). The solution became warm during
the addition, and a precipitate formed, giving a cloudy orange-
brown appearance. After the solution was stirred overnight,
10 mL of H2O was added, and the mixture was stirred for 10
min.
The layers were separated, and the organic layer was dried
with magnesium sulfate. Removal of the volatiles gave an
orange oil. The oil was vacuum distilled to give a light yellow
oil, boiling from 62 to 68 °C at 0.1 mmHg (6.64 g, 67% yield).
A second vacuum distillation gave a sample of elemental
purity, bp 64-66 °C at 0.1 mmHg. Anal. Calcd for C11H11N:
C, 84.04; H, 7.05; N, 8.91. Found: C, 83.83; H, 7.07; N, 8.85.
3-(2-Dim eth yla m in oeth yl)in d en e (11). Into an argon-
flushed round-bottom Schlenk flask were added 22.2 mL (0.190
mol) of indene, 150 mL of THF, and a magnetic stirring bar.
The flask was cooled to 0 °C, and 118.5 mL of 1.6 M n-BuLi
(0.190 mol) was added slowly via syringe. The reaction was
allowed to warm to room temperature and stir for 2 h. (2-
Chloroethyl)dimethylamine was generated via the solid-phase
reaction of (2-chloroethyl)dimethylamine hydrochloride and
powdered potassium hydroxide (1:2 molar ratio) and vacuum
distillation of the amine using a dry ice-2-propanol cooled
trap. The indenyllithium solution was cooled to 0 °C, and 20.4
g of the amine (0.190 mol) was added slowly via a pressure-
equalizing addition funnel (considerable heat is generated if
the addition is too fast). The solution turned cloudy upon
warming to room temperature and was allowed to stir for an
additional 2 h. The solution was hydrolyzed with 20 mL of
H2O, and the layers were separated. The organic layer was
dried with magnesium sulfate, filtered, and rotary evaporated.
The organic residue was vacuum distilled (112 °C at 0.01
mmHg) to give 33.5 g (94% yield) of a light yellow oil. The
sample was distilled a second time to obtain a sample of
elemental purity. 1H NMR (CDCl3): δ 7.47-7.20 (m, 4 H,
C6H4), 6.25 (bs, 1 H, dCH), 3.32 (bs, 2 H, CH2 of C5 ring), 2.78-
2.58 (m, 4 H, CH2CH2), 2.33 (s, 6 H, N(CH3)2). 13C NMR
(CDCl3): δ 145.3 (C3), 144.3 (C9), 142.5 (C8), 128.3, 126.0,
124.6, 123.7 (C4-7), 58.4 (CH2CH2N), 45.5 (NCH3), (CH2-
(2-Dim et h yla m in oet h yl)cyclop en t a d ien e (8). Com-
pound 8 was prepared by a modification of the method
developed by Wang et al.6 Sodium hydride (1.69 g, 70.4 mmol)
was placed in a 500-mL round-bottom Schlenk flask with 100
mL of THF and cooled to 0 °C, and 4.65 g (70.4 mmol) of freshly
distilled cyclopentadiene was added dropwise. The mixture
was allowed to stir until gas evolution ceased and all the
sodium hydride was consumed. Free amine was generated via
base extraction of (2-chloroethyl)dimethylamine hydrochloride.
Potassium hydroxide (6.05 g) was dissolved in 75 mL of water,
and 10.14 g of (2-chloroethyl)dimethylamine hydrochloride
(70.4 mmol) was added. The solution was extracted with two
50-mL portions of hexane. The organic layers were combined
and dried over magnesium sulfate. The cyclopentadienylso-
dium solution was placed in an ice bath, and the hexane
solution of the free amine was added dropwise via a pressure-
equalizing addition funnel. After the addition was complete,
the reaction mixture was heated at reflux for 4 h and allowed
to cool to room temperature. The cloudy yellow-brown suspen-
sion was hydrolyzed with 25 mL of water, and the layers were
separated. The organic layer was rotary evaporated, and the
resulting oil was vacuum distilled to give a colorless to light
yellow oil (6.57 g, 68% yield) at 42 °C and 0.5 mmHg (it is
necessary to cool the collection flask to -78 °C to prevent
substantial loss of product). 1H NMR (CDCl3, 200 MHz): δ

Pendent Aminoalkyl-Substituted CpTi Compounds
Organometallics, Vol. 17, No. 17, 1998 3781
CH2N), 26.2 (C1). Anal. Calcd for C13H17N: C, 83.37; H, 9.15;
N, 7.48. Found: C, 83.15; H, 9.07; N, 7.27.
white solid was collected on a Schlenk frit, washed several
times with pentane, and dried under vacuum. The solid
darkened during drying and was, therefore, placed in a
sublimer and heated to 90 °C and 0.03 mmHg, giving 2.80 g
(77.5% yield) of 16. 1H NMR (DMSO): δ 7.26-7.10 (m, 5 H,
aromatic), 5.73 (t, 2 H, C5H4), 5.56 (t, 2 H, C5H4), 2.75 (m, 4
H, CH2CH2). Anal. Calcd for C13H13Tl: C, 41.79; H, 3.51.
Found: C, 41.68; H, 3.54.
3-(2-Diisop r op yla m in oeth yl)in d en e (12). Indene (9.31
g, 78.6 mmol) was placed in a Schlenk tube with 50 mL of
THF and cooled to 0 °C, and 49.0 mL of 1.6 M n-BuLi (78.6
mmol) was added via syringe. After the solution was stirred
for 2 h at room temperature, 7.80 g (39.3 mmol) of (2-
chloroethyl)diisopropylamine hydrochloride was added as a
solid. Heat was evolved, and the solution became lighter. The
solution was allowed to stir overnight and was hydrolyzed with
20 mL of water. The layers were separated, and the organic
layer was dried over magnesium sulfate. Filtration and
removal of the solvent gave a red oil. The oil was vacuum
distilled twice at 0.01 mmHg, and the fraction boiling at 126-
127 °C was collected, giving 7.81 g (81.6% yield) of a yellow
oil. 1H NMR (CDCl3) δ 7.47-7.19 (m, 4 H, C6H4), 6.23 (bs, 1
H, dCH), 3.33 (bs, 2 H, CH2 of C5 ring), 3.09 (h, 2 H,
NCH(CH3)2, 2,72 (bs, 4 H, CH2CH2), 1.06 (d, 12 H, NCH(CH3)2.
Anal. Calcd for C17H24N: C, 83.89; H, 10.35; N, 5.74. Found:
C, 83.47; H, 10.28; N, 5.63.
3-(2-P yr id yleth yl)in d en e (13). 2-Pyridylethanol was con-
verted to (2-chloroethyl)pyridine hydrochloride by reaction
with 1 equiv of thionyl chloride in methylene chloride. The
resulting white solid was collected by suction filtration and
used as a crude material in the next step of the reaction.
Indene (7.8 g, 67.4 mmol) was dissolved in 50 mL of THF and
cooled to 0 °C, and 42.1 mL of 1.6 M n-BuLi (67.4 mmol) was
added by syringe. The solution was allowed to stir for 2 h,
and 6.00 g (33.7 mmol) of 2-chloroethylpyridine hydrochloride
was added as a solid. The solution became warm, and a solid
precipitated. After the solution was stirred overnight, 50 mL
of water was added, and the layers were separated. The
organic layer was dried over magnesium sulfate and filtered,
and the solvent was removed under vacuum. The resulting
oil was vacuum distilled, and the fraction boiling at 126-128
°C and 0.1 mmHg was collected (3.75 g, 50.3% yield). 1H NMR
(CDCl3): δ 8.58 (d, 1 H, pyr), 7.63-7.08 (m, 7 H, aromatic),
6.23 (bs, 1 H, dCH), 3.32 (bs, 2 H, CH2 of C5 ring), 3.21 (t, 2
H, CH2CH2), 3.02 (t, 2 H, CH2CH2). Anal. Calcd for C16H15N:
C, 86.84; H, 6.83; N, 6.33. Found: C, 86.57; H, 6.77; N, 6.15.
(2-P icolyl)cyclop en ta d ien ylth a lliu m (14). Freshly dis-
tilled (2-picolyl)cyclopentadiene (1.68 g, 10.7 mmol) was dis-
solved in 25 mL of diethyl ether, and 2.66 g (10.7 mmol) of
thallium ethoxide was added dropwise. A white crystalline
precipitate formed immediately. The solution was allowed to
stir for 20 min and then collected on a Schlenk filter. The
solid was washed twice with 30 mL of hexane. The white
platelike crystals (3.36 g, 87%) were sublimed at 100 °C and
0.001 mmHg to obtain a sample of elemental purity. 1H NMR
(DMSO): δ 8.38-8.36 (m, 1 H, aromatic), 7.72-7.63 (d of t, 1
H, aromatic), 7.32-7.28 (d, 1 H, aromatic), 7.21-7.14 (t, 1 H,
aromatic), 5.72-5.66 (m, 4 H, C5H4), 3.87 (s, 2 H, CH2). Anal.
Calcd for C11H10NTl: C, 36.64; H, 2.80; N, 3.88. Found: C,
36.99; H, 2.80, N, 3.85.
[η5-(2-P icolyl)cyclop en t a d ien yl]d ica r b on ylr h od iu m
(17). (2-Picolyl)cyclopentadienylthallium (1.06 g, 2.77 mmol)
was suspended in 25 mL of THF, 0.554 g (1.42 mmol) of
chlorodicarbonylrhodium dimer was added, and the solution
was allowed to stir overnight. The solvent was removed, and
the residue was extracted with hexane. Silica (3 g, 100-200
mesh) was added, and the solvent was removed and placed
on a 10- × 2-cm column packed dry with silica. Elution with
hexane, hexane/dichloromethane (50/50), and dichloromethane
gave no results. Elution with THF gave an orange band.
Removal of the solvent produced 0.61 g of a red oil (69% yield).
Vacuum distillation resulted in a single fraction as a red oil
boling at 92 °C and 0.05 mmHg. 1H NMR (CDCl3, 200 MHz):
δ 8.56 (m, 1 H, aromatic), 7.65 (d of t, 1 H, aromatic), 7.26-
7.13 (m, 2 H, aromatic), 5.51 (t, 2 H, C5H4), 5.34 (t, 2 H, C5H4),
3.82 (s, 2 H, CH2). FTIR (CH2Cl2) ν(CO) 2042.8, 1976.3 cm-1
.
Anal. Calcd for C13H10NO2Rh: C, 49.55; H, 3.20; N, 4.44.
Found: C, 49.82; H, 3.41; N, 4.41.
[η5-(2-Dim eth ylam in oeth yl)cyclopen tadien yl]dicar bon -
ylir id iu m (18). (2-Dimethylaminoethyl)cyclopentadienylthal-
lium (2.40 g, 7.047 mmol) and 2.33 g (6.40 mmol) of chlorodi-
carbonyl(pyridine)iridium were allowed to react in 50 mL of
benzene. The suspension was heated at reflux for 2 d and
allowed to cool to room temperature. The solution was filtered
and the solvent removed under vacuum, giving 2.46 g (76%
yield) of a yellow oil. The oil was analyzed by 1H NMR and
FTIR and was found to be identical to 18 obtained previously.8
The crude material was as pure as the distilled product
obtained via the lithium salt.8
[η5-(2-P h en ylet h yl)cyclop en t a d ien yl]d ica r b on ylr h o-
d iu m (19). (2-Phenylethyl)cyclopentadienylthallium (1.50 g,
4.014 mmol) was suspended in 25 mL of THF, and 0.780 g
(2.007 mmol) of chlorodicarbonylrhodium dimer was added.
The solution was stirred overnight and filtered. Silica gel (5
g, 100-200 mesh) was added, and the solvent was removed.
The residue was added to a 10- × 2-cm dry packed column of
silica. On elution with hexane, an orange band was obtained.
Removal of the solvent gave 1.21 g of an orange oil (91.8%
yield). Microdistillation of the product at 0.005 mmHg gave
a single fraction boiling at a pot temperature of 110 °C. 1H
NMR (CDCl3): δ 7.34-7.16 (m, 5 H, aromatic), 5.38 (t, 2 H,
C5H4), 5.30 (t, 2 H, C5H4), 2.84 (m, 2 H, CH2), 2.63 (m, 2 H,
CH2). Anal. Calcd for C15H13O2Rh: C, 54.90; H, 3.99.
Found: C, 54.81; H, 3.94.
[η5-(2-P h en yleth yl)cyclop en ta d ien yl](η5-p en ta m eth yl-
cyclop en ta d ien yl)d ich lor otita n iu m (20). (2-Phenylethyl)-
cyclopentadienylthallium (1.30 g, 3.48 mmol) was suspended
in 50 mL of benzene, and 1.46 g (5.04 mmol) of pentamethyl-
cyclopentadienyltitanium trichloride was added. The solution
turned yellow-orange after stirring overnight. Filtration and
removal of the solvent gave a purple solid. The solid was
dissolved in a minimum of toluene and cooled to -20 °C to
give red crystals, which proved to be pentamethylcyclopenta-
dienyltitanium trichloride. Removal of the solvent and extrac-
tion with hot hexane gave a small amount of crystals after
cooling to room temperature. The solution was filtered and
(2-Dim eth ylam in oeth yl)cyclopen tadien ylth alliu m (15).
Freshly distilled (2-dimethylaminoethyl)cyclopentadiene (0.64
g, 4.66 mmol) was dissolved in 25 mL of diethyl ether, and
1.16 g (4.66 mmol) of thallium ethoxide was added by syringe.
After 1 min of stirring, a yellow precipitate formed. The
solution was stirred for 2 h, and the solid was collected on a
Schlenk filter (1.55 g, 97.9% yield). A sample was sublimed
at 132 °C and 0.001 mmHg to give a white solid. 1H NMR
(DMSO) δ (5.79-5.75 (m, 4 H, C5H4), 2.50 (bs, 4 H, CH2CH2),
2.06 (s, 6 H, N(CH3). Anal. Calcd for C9H14NTi: C, 31.74; H,
4.14; N, 4.11. Found: C, 31.81; H, 4.12; N, 4.05.
1
cooled to -20 °C to give 0.77 g (52% yield) of red crystals. H
NMR (CDCl3): δ 7.26-7.12 (m, 5 H, aromatic), 5.99-5.95 (m,
4 H, C5H4), 3.01-2.94 (m, 4 H, CH2), 2.03 (s, 15 H, CH3). Anal.
Calcd for C23H28Cl2Ti: C, 65.26; H, 6.67. Found: C, 65.34; H,
6.66.
(2-Dim e t h yla m in oe t h yl)t r im e t h ylsilylcyclop e n t a -
d ien e (21). Freshly distilled (2-dimethylaminoethyl)cyclo-
(2-P h en yleth yl)cyclopen tadien ylth alliu m (16). (2-Phen-
ylethyl)cyclopentadiene (1.66 g, 9.67 mmol) was dissolved in
30 mL of diethyl ether, and 2.41 g (9.67 mmol) of thallium
ethoxide was added. A white precipitate formed immediately,
and the reaction mixture gelled. An additional 20 mL of ether
was added, and the reaction was allowed to stir for 1 h. The

3782 Organometallics, Vol. 17, No. 17, 1998
Blais et al.
pentadiene (3.48 g, 21.9 mmol) was dissolved in 50 mL of
diethyl ether and cooled to 0 °C, and 13.7 mL of 1.6 M n-BuLi
in hexane (21.9 mmol) was added slowly via syringe. The
solution was allowed to stir at room temperature for 4 h, and
3.04 g (21.9 mmol) of chlorotrimethylsilane was added. After
the solution was stirred overnight and the solvent removed,
the residue was extracted with 50 mL of pentane and filtered.
Removal of the pentane gave 5.01 g of a yellow oil (87% yield).
1H NMR (CDCl3, 200 MHz): δ 6.70-6.05 (m, 3 H, C5H4), 3.28-
2.85 (m, 2 H, sp3 ring), 2.65-2.37 (m, 4 H, CH2CH2N), 2.28
and 2.27 (s, 6 H, NCH3), 0.14, 0.13, -0.04 (s, 9 H, SiCH3).
[η5-(2-Dim eth ylam in oeth yl)cyclopen tadien yl]tr ich lor o-
tita n iu m (2). In a Schlenk tube were placed 100 mL of
dichloromethane and 5.01 g (23.9 mmol) of (2-dimethylami-
noethyl)trimethylsilylcyclopentadiene. The solution was cooled
to -78 °C, and 2.63 mL of titanium tetrachloride was added
via a syringe. A dark orange solution formed immediately.
The solution was allowed to warm to room temperature, and
the oily residue was triturated with 100 mL of pentane. The
solid was collected on a Schlenk filter and dried under vacuum
to give 6.10 g of a highly air- and moisture-sensitive yellow
powder (88% yield). 1H NMR (CD2Cl2, 80 MHz): δ 6.95 (t, 2
H, C5H4), 6.81 (t, 2 H, C5H4), 3.16 (m, 4 H, CH2CH2), 2.65 (s,
6 H, NCH3).
Anal. Calcd for C11H10Cl3NTi: C, 42.56; H, 3.25; N, 4.51.
Found: C, 43.02; H, 3.57; N, 4.61.
[3-(2-Dim eth yla m in oeth yl)-1-in d en yl]tr ibu tyltin (25).
Into an argon-purged Schlenk tub were placed 4.59 g (24.5
mmol) of 3-(2-dimethylaminoethyl)indene and 100 mL of THF,
and the solution was cooled in an ice bath. To the solution
was added 15.3 mL of 1.6 M n-BuLi in hexane (24.5 mmol).
The solution was allowed to warm to room temperature and
stir for 4 h (note: this reaction takes all 4 h). To the bright
red solution was added 7.977 g (24.5 mmol) of chlorotributyltin,
and the reaction was allowed to stir for 2 d (this reaction is
very slow). The solvent was removed under vacuum, and the
orange residue was extracted with pentane. The extracts were
combined and filtered to give an orange solution and a white
solid. The solvent was removed to give an orange oil which
turned slightly cloudy on standing. Repeated extraction with
pentane and filtration gave a clear orange oil. 1H NMR
(CDCl3): δ 7.50-7.13 (m, 4 H, C6H4), 6.46 (bs, 1 H, dCH), 4.01
(bs, 1 H, CH2 of C5 ring), 2.85 (m, 2 H, NCH2), 2.65 (m, 2 H,
ind-CH2), 2.34 (s, 6 H, N(CH3)2), 1.36-0.69 (2 m, 27 H, SnBu3).
[η5-1-(2-Dim et h yla m in oet h yl)in d en yl]t r ich lor ot it a n -
iu m (26). In a Schlenk tube were placed 3.71 g (6.96 mmol)
of [3-(2-dimethylaminoethyl)-1-indenyl]tributyltin and 50 mL
of dichloromethane. The solution was cooled to -78 °C, and
1.32 g (6.96 mmol) of titanium tetrachloride was added via
syringe. The solution turned dark green immediately. The
solvent was removed, and the resulting oily green solid was
washed two times with hexane and dried under vacuum. The
green solid was highly air sensitive and turned red-brown with
the slightest exposure to air. However, the crude material was
of sufficient purity for polymerization studies. 1H NMR
(CDCl3): δ 7.98-7.41 (m, 4 H, C6H4), 7.09 (d, 1 H, C5H2), 7.01
(d, 1 H, C5H2), 3.40 (m, 4 H, CH2CH2), 2.74 (s, 6 H, NCH3).
(2-P h en yleth yl)tr im eth ylsilylcyclop en ta d ien e (27). In
a 100-mL Schlenk flask were placed 1.08 g (6.34 mmol) of
2-phenylethylcyclopentadiene and 20 mL of THF. The reaction
mixture was cooled to 0 °C, and 4.0 mL of 1.6 M n-BuLi (6.4
mmol) was added, turning the solution a dark red. The
solution was stirred overnight, and 1.5 mL (6.4 mmol) of
chlorotrimethylsilane was added. The reaction was stirred for
8 h and turned a light yellow. The solvent was removed, and
the residue was extracted with pentane. After filtration, the
solvent was removed under vacuum, giving a light yellow oil.
[(2-P icolyl)cyclop en ta d ien yl]tr im eth ylsila n e (22). (2-
Picolyl)cyclopentadiene (7.09 g, 45.1 mmol) was dissolved in
50 mL of THF, and 30 mL of 1.6 M n-BuLi (45.1 mmol) was
added dropwise. The solution turned dark red immediately
but was allowed to stir at room temperature for 1 h. Chlo-
rotrimethylsilane (4.9 g, 5.8 mL, 45 mmol) was added by
syringe, and the solution was allowed to stir overnight. The
THF was removed under vacuum, and the yellow oily solid
was extracted with 50 mL of pentane. Filtration and removal
of the pentane gave an orange oil (9.46 g, 91.5% yield). The
oil was vacuum distilled at 96 °C and 0.1 mmHg to give a light
yellow oil. 1H NMR (CDCl3): δ 8.49 (m, 1 H, aromatic), 7.57
(t, 1 H, aromatic), 7.24-7.07 (m, 2 H, aromatic), 6.41 and 6.16
(bs, 2 H, vinylic), 3.90 (bs, 2 H, CH2), 3.26-2.93 (m, 1 H, CH
sp3). Anal. Calcd for C14H19NSi: C, 73.30; H, 8.35; N, 6.11.
Found: C, 72.84; H, 8.73; N, 5.73.
[η5-(2-P icolyl)cyclopen tadien yl]dich lor otitan iu m µ-Oxo
Dim er Dih yd r och lor id e (24). [(2-Picolyl)cyclopentadienyl]-
trimethylsilane (1.32 g, 5.36 mmol) was dissolved in 50 mL of
toluene, and 1.01 g (5.36 mmol) of titanium tetrachloride was
added slowly at room temperature. A bright orange precipitate
formed immediately. The solution was filtered, and the solid
was washed with hexane, dried under vacuum, analyzed by
1H NMR, and determined to be the µ-oxo dimer. The solid
was extracted with 50 mL of dichloromethane, and the solvent
was removed after filtration to give 2.36 g of 24 as a bright
orange solid. The solid was washed with pentane and toluene
and placed under high vacuum overnight to give a sample of
elemental purity. 1H NMR (CDCl3): δ 8.90 (m, 2 H, aromatic),
7.81 (t, 2 H, aromatic), 7.39 (m, 4 H, aromatic), 7.10-7.08 (m,
4 H, C5H4), 4.46 (s, 4 H, CH2). Anal. Calcd for C22H22Cl6ON2-
Ti2: C, 41.35; H, 3.47; N, 4.38. Found: C, 41.19; H, 3.03; N,
4.22.
A
1H NMR spectrum was taken and exhibited the expected
values for the trimethylsilyl derivative. 1H NMR (CDCl3, 200
MHz): δ 7.34-7.19 (m, 5 H, aromatic), 6.49-6.14 (m, 3 H,
vinylic), 3.29 (bs, 1 H, sp3 of C5 ring), 2.94-2.66 (m, 4 H, CH2-
CH2), 0.17, -0.06 (m, 9 H, Si(CH3)3).
[η5-(2-P h en ylet h yl)cyclop en t a d ien yl]t r ich lor ot it a n -
iu m (28). The yellow oil 27 (6.34 mmol) was placed in 40 mL
of dichloromethane and cooled to -78 °C, and 1.2 g (6.4 mmol)
of titanium tetrachloride was added. The reaction mixture was
allowed to warm to room temperature and was stirred for 4
h. The solvent was removed under vacuum, giving an orange
powder after two triturations with pentane. The powder was
dried under vacuum to give 1.65 g (80.5% yield) of 28.
A
sample was dissolved in a minimum amount of toluene, and
hexane was layered on top of the toluene solution. After the
solution was cooled for 3 d at -20 °C, orange crystals were
obtained. 1H NMR (CDCl3): δ 7.34-7.12 (m, 5 H, aromatic),
6.92 (t, 2 H, C5H4), 6.76 (t, 2 H, C5H4), 3.19 (m, 2 H, CH2),
2.98 (m, 2 H, CH2). Anal. Calcd for C13H13Cl3Ti: C, 48.27; H,
4.05. Found: C, 48.70; H, 3.92.
[η5-(2-Dim et h yla m in oet h yl)cyclop en t a d ien yl]t r iiso-
p r op oxytita n iu m (29). To a hexane solution containing
0.920 g of chlorotitanium triisopropoxide (3.53 mmol) was
added 1.23 g (3.61 mmol) of (2-dimethylaminoethyl)cyclopen-
tadienylthallium. The solution changed color immediately but
was stirred overnight. Filtration gave a gray solid and an
orange solution. The hexane was removed under vacuum, and
the resulting orange oil was vacuum distilled, giving a light
[η5-(2-P icolyl)cyclop en ta d ien yl]tr ich lor otita n iu m (23).
In a 100-mL Schlenk flask were added 0.69 g (1.90 mmol) of
2-picolylcyclopentadienylthallium, 0.360 g (2.00 mmol) of
titanium tetrachloride, and 50 mL of toluene. The reaction
mixture was stirred at room temperature for 24 h. The
solution turned yellow immediately, and gradually a white
precipitate formed. The solution was filtered, and the solvent
was removed under vacuum. The yellow solid was trituated
with hexane, and the solid was collected on a Schlenk filter.
The solid was sublimed at 194 °C and 0.005 mmHg to give
0.49 g (83% yield) of an orange crystalline solid. 1H NMR
(CDCl3): δ 8.93 (d, 1 H, aromatic), 7.85 (t, 1 H, aromatic), 7.40
(m, 2 H, aromatic), 7.14 (m, 4 H, C5H4), 4.47 (s, 2 H, CH2),

Pendent Aminoalkyl-Substituted CpTi Compounds
Organometallics, Vol. 17, No. 17, 1998 3783
yellow oil of bp 112-113 °C at 0.001 mmHg. 1H NMR (CDCl3,
200 MHz): δ 6.11(m, 2 H, C5H4), 6.07 (m, 2 H, C5H4), 4.54
(hept, 3 H, CH(CH3)3), 2.89 (t, 2 H, CH2), 2.59 (t, 2 H, CH2),
2.19 (s, 6 H, NCH3), 1.20 (d, 18 H, CH(CH3)2, (80 MHz) (6.11
(m, 4 H, C5H4), 4.54 (hept, 3 H, CH(CH3)2, 2.66 (m, 4 H, CH2-
CH2), 2.29 (s, 6 H, NCH3), 1.20 (d, 18 H, CH(CH3)2). Anal.
Calcd for C18H35NO3Ti: C, 59.83; H, 9.76; N, 3.99. Found: C,
58.99; H, 9.99; N, 3.43.
[η5-1-(2-Diisopr opylam in oeth yl)in den yl]tr iisopr opoxy-
tita n iu m (33). In a Schlenk tube were placed 1.13 g (4.6
mmol) of 3-(2-diisopropylaminoethyl)indene and 50 mL of
hexane. The solution was cooled to 0 °C, and 2.9 mL of 1.6 M
n-BuLi (4.6 mmol) was added via syringe. After the solution
was stirred overnight at room temperature, 1.2 g (4.6 mmol)
of chlorotitanium triisopropoxide was added, causing the
solution to turn orange and a white precipitate to form. The
reaction mixture was stirred overnight and filtered. Removal
of the solvent gave an orange oil which was analyzed by 1H
NMR and found to be the desired product. All attempts at
purification failed. 1H NMR (CDCl3): δ 7.43-7.17 (m, 4 H,
C6H4), 6.81 (d, 1 H, C5H2), 6.58 (d, 1 H, C5H2), 4.48 (hept, 3 H,
OCH(CH3)2), 3.99 (t, 2 H, CH2), 3.55 (t, 2 H, CH2), 3.01 (hept,
2 H, NCH(CH3)2), 1.23 (d, 18 H, OCH(CH3)2), 1.07 (m, 12 H,
NCH(CH3)2).
[η5-(2-Diisop r op yla m in oeth yl)cyclop en ta d ien yl]tr iiso-
p r op oxytita n iu m (30). To a solution of 2.42 g (12.5 mmol)
of 2-diisopropylaminocyclopentadiene in 100 mL of THF was
added 7.8 mL of 1.6 M n-BuLi (12.5 mmol) in hexane at 0 °C.
The reaction mixture was stirred for 6 h at room temperature,
and 3.25 g (12.5 mmol) of chlorotitanium triisopropoxide was
added as a solid. After the solution was stirred overnight, the
THF was removed under vacuum, and the residue was
extracted 2 times with 50 mL of pentane. Filtration via
cannula and removal of the solvent under vacuum gave a
yellow oil. All attempts to vacuum distill the product led to
[η5-1-(2-P yr id ylet h yl)in d en yl]t r iisop r op oxyt it a n iu m
(34). In a Schlenk tube were placed 2.76 g (12.4 mmol) of 3-(2-
pyridylethyl)indene, 10 mL of THF, and 50 mL of hexane. The
solution was cooled to 0 °C, and 7.8 mL of 1.6 M n-BuLi (12.4
mmol) was added by syringe. The solution was allowed to stir
overnight, and 3.24 g (12.4 mmol) of chlorotitanium triisopro-
poxide was added as a solid. A white solid formed im-
mediately, and the solution turned orange. The mixture was
allowed to stir overnight, and the solvent was removed under
vacuum. Extraction with hexane and filtration gave an orange
solution. Removal of the solvent gave a red-orange oil. 1H
NMR (CDCl3): δ 8.54 (m, 1 H, pyr), 7.58-7.07 (m, 7 H, pyr
and aromatic), 6.83 (d, 1 H, C5 ring), 6.57 (d, 1 H, C5 ring),
4.51 (hept, 3 H, OCH(CH3)2), 3.22-2.77 (m, 4 H, CH2CH2), 1.24
(d, 18 H, OCH(CH3)2).
P olym er iza tion a n d P olym er Ch a r a cter iza tion . Po-
lymerization grade ethylene and propylene were dried and
purified by passing them through Matheson gas purifiers
(model 6436). Polymerizations were carried out in 250-mL
crown-capped glass pressure reactors with magnetic stirring
and thermostated to the desired temperature. The system was
first evacuated and flushed with argon three times and then
charged with 50 mL of toluene (freshly distilled from Na/K
alloy). The system was evacuated again and charged with the
appropriate gaseous monomer. In the case of liquid monomers,
5 mL of styrene was injected into the bottle.
The order of reagent addition was monomer, MAO, and
catalyst. All of the triisopropoxytitanium catalysts were
preactivated by addition of 2000 equiv of MAO to the catalyst
solution and stirring for 30 min. The polymerization mixture
was quenched with 2% HCl in methanol, filtered, and washed
with methanol. The polymer samples were dried in a vacuum
oven at 0.1 mmHg and 70 °C to a constant weight.
The activity values were calculated using the measured
solubility of propylene and ethylene or the known number of
moles of liquid monomer injected. DSC melting endotherms
were obtained on either Perkin-Elmer DSC-4 or Du Pont TA
2000, SCD 10 instruments. Molecular weight determinations
were made by viscosity measurements in Decalin at 135 °C.
The procedures used to polymerize styrene12 and ethylene
or propylene13 have been given in detail previously.
1
decomposition. However, the product was determined by H
NMR to be pure enough for polymerization studies.1H NMR
(CDCl3, 200 MHz): δ 6.14 (m, 2 H, C5H4), 6.11 (m, 2 H, C5H4),
4.54 (hept, 3 H, OCH(CH3)2), 3.05 (hept, 3 H, NCH(CH3)2), 2.66
(bs, 4 H, CH2CH2), 1.20 (d, 18 H, OCH(CH3)2), 1.02 (d, 12 H,
NCH(CH3)2).
[η5-(2-P icolyl)cyclop en t a d ien yl]t r iisop r op oxyt it a n -
iu m (31). (2-Picolyl)cyclopentadienylthallium (2.80 g, 7.76
mmol) was placed in 50 mL of diethyl ether, and 2.02 g (7.76
mmol) of chlorotitanium triisopropoxide was added. The
solution was stirred overnight, and the ether was removed
under vacuum. The yellow cloudy residue was extracted with
hexane and filtered, leaving a gray precipitate. Removal of
the hexane under vacuum gave 2.91 g of a yellow oil (98%
yield). A sample of the oil was vacuum distilled at 0.001
mmHg, but the sample decomposed on heating before distilling
at approximately 95 °C. The original crude material was
extracted with hexane and filtered, and the solvent was
removed. After being placed on high vacuum and heating to
40 °C overnight, a sample was sent for elemental analysis. 1H
NMR (CDCl3, 200 MHz): δ 8.56 (m, 1 H, aromatic), 7.59 (t, 1
H, aromatic), 7.19 (m, 2 H, aromatic), 6.19 (t, 2 H, C5H4), 6.12
(t, 2 H, C5H4), 4.57 (hept, 3 H, CH(CH3)2), 4.11 (s, 2 H, CH2),
1.12 (d, 18 H, CH(CH3)2). Anal. Calcd for C20H31NO3Ti: C,
62.98; H, 8.19; N, 3.67. Found: C, 59.47; H, 7.93, N, 3.41.
[η5-1-(2-Dimethylaminoethyl)indenyl]triisopropoxytitan-
iu m (32). In a Schlenk tube were placed 5.06 g (27.0 mmol)
of 3-(2-dimethylaminoethyl)indene, 50 mL of THF, and 16.9
mL of 1.6 M n-BuLi (27.0 mmol). The solution was stirred
overnight, and 7.04 g of chlorotitanium triisopropoxide was
added. The solution turned very dark, and a precipitate
formed. The THF was removed under vacuum, and the red
tarry residue was extracted with hexane. Filtration gave a
red-orange solution, and removal of the solvent resulted in a
red oil (l0.74 g, 97.2% yield). 1H NMR (CDCl3): δ 7.44-7.15
(m, 4 H, C6H4), 6.80 (d, 1 H, C5H2), 6.53 (d, 1 H, C5H2), 4.49
(hept, 3 H, CH(CH3)2), 2.67 (m, 4 H, CH2CH2), 2.25 (s, 6 H,
NCH3), 1.25 (d, 18 H, CH(CH3)2).
Ack n ow led gm en t. The authors are grateful to
Barrie Rhodes for technical assistance.
OM980118C