Synthesis of nonbridged (anilide)(cyclopentadienyl)titanium(IV) complexes of the type Cp′TiCl2[N(2,6-Me2C6H3)(R)] and their use in catalysis for olefin polymerization

Article abstract of DOI:10.1021/om020179h

(Anilide)(cyclopentadienyl)titanium(IV) complexes of the type Cp′TiCl₂[N(2,6-Me₂C₆H₃)-(R)] (8a-d: Cp* = C₅Me₅ (Cp*), 1,3-Me₂C₅H₃, Cp; R = SiMe₃, Si^tBuMe₂) have been prepared by the reaction of Cp′TiCl₃ with the corresponding lithium anilide in toluene. The structure of (1,3-Me₂C₅H₃)TiCl₂[N(2,6-Me₂ C₆H₃)(SiMe₃)] (8b) has been determined by X-ray crystal-lography. These complexes exhibited high catalytic activities for ethylene polymerization in the presence of methylaluminoxane (MAO); especially Cp*TiCl₂[N(2,6-Me₂C₆H₃)(SiMe ₃)] (8a) exhibited the highest catalytic activity (108s 0 kg of PE/((mol of Ti) h), ethylene 6 atm at 25 °C), whereas the analogous zirconium complex Cp*ZrCl₂[N(2,6-Me₂C₆H₃)(SiMe ₃)] (9a) showed a lower activity (637 kg of PE/((mol of Ti) h)) under the same conditions. The activity by Cp′TiCl₂[N(2,6-Me₂C₆H₃)(SiMe ₃)] for the ethylene polymerization increased in the order Cp* > 1,3-Me₂C₅H₃, Cp. The molecular weight for the resultant polyethylene depended upon the cyclopentadienyl fragment used. The low catalytic activity was observed for propylene polymerizations by 8a; the resultant polymer was atactic and possessed high molecular weight with narrow polydispersity.

Full text of DOI:10.1021/om020179h

3042
Organometallics 2002, 21, 3042-3049
Syn th esis of Non br id ged
(An ilid e)(cyclop en ta d ien yl)tita n iu m (IV) Com p lexes of
th e Typ e Cp ′TiCl2[N(2,6-Me2C6H3)(R)] a n d Th eir Use in
Ca ta lysis for Olefin P olym er iza tion
Kotohiro Nomura* and Kensaku Fujii
Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST),
8916-5 Takayama, Ikoma, Nara 630-0101, J apan
Received March 4, 2002
(Anilide)(cyclopentadienyl)titanium(IV) complexes of the type Cp′TiCl2[N(2,6-Me2C6H3)-
(R)] (8a -d : Cp′ ) C5Me5 (Cp*), 1,3-Me2C5H3, Cp; R ) SiMe3, SitBuMe2) have been prepared
by the reaction of Cp′TiCl3 with the corresponding lithium anilide in toluene. The structure
of (1,3-Me2C5H3)TiCl2[N(2,6-Me2C6H3)(SiMe3)] (8b) has been determined by X-ray crystal-
lography. These complexes exhibited high catalytic activities for ethylene polymerization in
the presence of methylaluminoxane (MAO); especially Cp*TiCl2[N(2,6-Me2C6H3)(SiMe3)] (8a )
exhibited the highest catalytic activity (1080 kg of PE/((mol of Ti) h), ethylene 6 atm at 25
°C), whereas the analogous zirconium complex Cp*ZrCl2[N(2,6-Me2C6H3)(SiMe3)] (9a ) showed
a lower activity (637 kg of PE/((mol of Ti) h)) under the same conditions. The activity by
Cp′TiCl2[N(2,6-Me2C6H3)(SiMe3)] for the ethylene polymerization increased in the order Cp*
> 1,3-Me2C5H3, Cp. The molecular weight for the resultant polyethylene depended upon
the cyclopentadienyl fragment used. The low catalytic activity was observed for propylene
polymerizations by 8a ; the resultant polymer was atactic and possessed high molecular
weight with narrow polydispersity.
In tr od u ction
pected to exhibit unique characteristics as olefin po-
lymerization catalysts that would be different from
those by ordinary metallocene type and/or so-called
“constrained geometry” (hybrid “half-metallocene”) type
catalysts.21-30 In addition, the synthesis of this type is
not complicated (shorter synthetic steps with relatively
Olefin polymerization by homogeneous transition-
metal complex catalysis has attracted particular atten-
tion in the field of organometallic chemistry, catalysis,
and polymer chemistry. Many contributions have thus
been made concerning this topic, especially using early-
transition-metal complexes.1 Among them, nonbridged
half-metallocene group 4 transition-metal complexes of
the type Cp′M(L)X2 (Cp′ ) cyclopentadienyl group; M
) Ti, Zr, Hf; L ) anionic ligand such as OAr, NR2, NPR3;
X ) halogen, alkyl)2-20 have attracted considerable
attention, because this type of catalyst has been ex-
(10) Report concerning ethylene polymerization using the CpTiCl2-
(O-4-XC6H4)-Et2AlCl (classical Ziegler type) catalyst system: Skupin-
ski, W.; Wasilewski, A. J . Organomet. Chem. 1985, 282, 69.
(11) Antin˜olo, A.; Carrillo-Hermosilla, F.; Corrochano, A.; Ferna´n-
dez-Baeza, J .; Lara-Sanchez, A.; Ribeiro, M.; Lanfranchi, M.; Otero,
A.; Pellinghelli, M. A.; Portela, M. F.; Santos, J . V. Organometallics
2000, 19, 2837.
(12) Shah, S. A. A.; Dorn, H.; Voigt, A.; Roesky, H. W.; Parisini, E.;
Schmidt, H.-G.; Noltemeyer, M. Organometallics 1996, 15, 3176.
(13) Doherty, S.; Errington, R. J .; J arvis, A. P.; Collins, S.; Clegg,
W.; Elsegood, M. R. J . Organometallics 1998, 17, 3408.
(14) Stephan, D. W.; Stewart, J . C.; Gue´rin, F.; Spence, R. E. v. H.;
Xu, W.; Harrison, D. G. Organometallics 1999, 18, 1116.
(15) Richter, J .; Edelmann, F. T.; Noltemeyer, M.; Schmidt, H.-G.;
Schmulinson, M.; Eisen, M. S. J . Mol. Catal. A 1998, 130, 149.
(16) Vollmerhaus, R.; Shao, P.; Taylor, N. J .; Collins, S. Organome-
tallics 1999, 18, 2731.
* To whom correspondence should be addressed. Tel: +81-743-72-
6041. Fax: +81-743-72-6049. E-mail: nomurak@ms.aist-nara.ac.jp.
(1) For example (review): (a) Brintzinger, H. H.; Fischer, D.;
Mu¨lhaupt, R.; Rieger, B.; Waymouth, R. M. Angew. Chem., Int. Ed.
Engl. 1995, 34, 1143. (b) Kaminsky, W. Macromol. Chem. Phys. 1996,
197, 3903. (c) Kaminsky, W.; Arndt, M. Adv. Polym. Sci. 1997, 127,
143. (d) Suhm, J .; Heinemann, J .; Wo¨rner, C.; Mu¨ller, P.; Stricker, F.;
Kressler, J .; Okuda, J .; Mu¨lhaupt, R. Macromol. Symp. 1998, 129, 1.
(e) McKnight, A. L.; Waymouth, R. M. Chem. Rev. 1998, 98, 2587. (f)
Britovsek, G. J . P.; Gibson, V. C.; Wass, D. F. Angew. Chem., Int. Ed.
1999, 38, 429.
(17) J ayaratne, K. C.; Sita, L. R. J . Am. Chem. Soc. 2000, 122, 958.
(18) Sita, L. R.; Babcock, R. Organometallics 1998, 17, 5228.
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J . Am. Chem. Soc. 2000, 122, 10490.
(2) Ewart, S. W.; Baird, M. C. Top. Catal. 1999, 7, 1.
(3) Baird, M. C. Chem. Rev. 2000, 100, 1471.
(4) Nomura, K.; Naga, N.; Miki, M.; Yanagi, K.; Imai, A. Organo-
metallics 1998, 17, 2152.
(20) Keaton, R. J .; J ayaratne, K. C.; Henningsen, D. A.; Koterwas,
L. A.; Sita, L. R. J . Am. Chem. Soc. 2001, 123, 6197.
(21) Canich, J . A. M.; Hlatky, G. G.; Turner, H. W. U.S. Patent 542,-
236, 1990.
(5) Nomura, K.; Naga, N.; Miki, M.; Yanagi, K. Macromolecules
1998, 31, 7588.
(6) Nomura, K.; Komatsu, T.; Imanishi, Y. J . Mol. Catal. A 2000,
152, 249.
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159, 127.
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2000, 33, 3187.
(22) Canich, J . A. M. U.S. Patent 5,026,798, 1991.
(23) Canich, J . A. M. Eur. Pat. Appl. 420,436, 1991.
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10.1021/om020179h CCC: $22.00 © 2002 American Chemical Society
Publication on Web 06/05/2002

(Anilide)(cyclopentadienyl)titanium(IV) Complexes
Organometallics, Vol. 21, No. 14, 2002 3043
Ch a r t 1
Sch em e 1
Ch a r t 2
interest for exploring the possibility of nonbridged
(anilide)(cyclopentadienyl)titanium(IV) complexes as the
olefin polymerization catalyst. The synthesis of analo-
gous zirconium and hafnium complexes (2) has already
been reported by Roesky et al.,12 but reports concerning
the synthesis and catalytic activity for olefin polymer-
ization with related titanium complexes have not been
reported so far. One related report, by Teuben and
Linden,32 is known for the synthesis of CpTiCl2(NHPh)
from CpTiCl3 with Me3SiN(H)Ph, but this complex
readily decomposes to give the bridged imido dimer
[CpTiCl]2(µ-PhN)2 upon heating (Scheme 1). Therefore,
we first examined the possibility of preparing a series
of titanium(IV) complexes of this type, explored their
thermal stability, and performed an X-ray crystal-
lographic analysis. In this paper, we wish to introduce
our results concerning the synthesis of various com-
plexes of this type, Cp′TiCl2[N(2,6-Me2C6H3)(R)] (R )
SiMe3 and Cp′ ) Cp* (8a ), 1,3-Me2C5H3 (8b), Cp (8c);
R ) SitBuMe2 and Cp′ ) Cp (8d ; Chart 2), and the effect
of both cyclopentadienyl and anilide groups on olefin
polymerization.33
high yield), and the ligand modification sterically and/
or electronically should be thus easier especially than
the ordinary bridged half-metallocene type complexes.
There are several examples that have already been
known as efficient catalyst precursors for ethylene or
1-hexene homopolymerization, and these (1-7) are
listed in Chart 1. However, only a few reports concern-
ing ligand effects in ethylene/R-olefin copolymerization
and/or concerning detailed polymerization behavior with
these complexes have been published.
We have reported that the nonbridged (cyclopenta-
dienyl)(aryloxy)titanium(IV) complex-MAO catalyst sys-
tem, especially 1a , exhibited exceptionally high catalytic
activity not only for ethylene polymerization but also
for ethylene/R-olefin copolymerization.4,5,8,9 Moreover,
the efficient catalyst precursor toward both styrene
homopolymerization and ethylene/styrene copolymeri-
zation could be transferred only by replacing the sub-
stituent on the Cp′ groups (from 1a to 1b).31
Resu lts a n d Discu ssion
1. Syn th eses of Cp ′TiCl2[N(2,6-Me2C6H3)(R)] (8,
Cp ′ ) Cp *, 1,3-Me2C5H3, Cp ; R ) SiMe3, SitBu Me2)
an d Cp*Zr Cl2[N(2,6-Me2C6H3)(SiMe3)] (9a). Cp*TiCl2-
[N(2,6-Me2C6H3)(SiMe3)] (8a ) could be prepared in
relatively high yield (78%) by the reaction of Cp*TiCl3
with LiN(2,6-Me2C6H3)(SiMe3) in toluene under reflux
conditions (12 h), although 8a could not be isolated from
the mixture if the reaction was performed at room
temperature or at 50 °C (Cp*TiCl3 was recovered
instead). This is the related method for preparing
(amide)(cyclopentadienyl)titanium(IV) complexes of the
With regard to the relevance to the above Cp-
aryloxy-titanium chemistry, we thus have a strong
(28) du Plooy, K. L.; Moll, U.; Wocadlo, S.; Massa, W.; Okuda, J .
Organometallics 1995, 14, 3129.
(29) Carpenetti, D. W.; Kloppenburg, L.; Kupec, J . T.; Petersen, J .
L. Organometallics 1996, 15, 1572.
(30) McKnight, A. L.; Masood, M. A.; Waymouth, R. M. Organome-
tallics 1997, 16, 2879.
(31) Nomura, K.; Komatsu, T.; Imanishi, Y. Macromolecules 2000,
33, 8122.
(32) Vroegop, C. T.; Teuben, J . H.; van Bolhuis, F.; van der Linden,
J . G. M. J . Chem. Soc., Chem. Commun. 1983, 550.
(33) We have also found that the Cp*TiCl2[NMe(Cy)]-MAO catalyst
exhibited remarkable catalytic activity for ethylene polymerization:
Nomura, K. Unpublished results.

3044 Organometallics, Vol. 21, No. 14, 2002
Nomura and Fujii
Sch em e 2
pound including decomposed compounds or some im-
purities (Scheme 3). The reaction in xylene at 130 °C
for 2-4 days was also attempted, but the desired
complex, Cp*TiCl2[N(2,6-iPr2C6H3)(SiMe3)], or related
products could not be isolated. These results are also
interesting in contrast with the synthesis of analogous
zirconium and hafnium complexes that were prepared
in high yield under mild conditions (room temperature
in Et2O). Attempts to prepare Cp*TiCl2[N(2,6-Me2C6H3)-
(SitBuMe2)] from the reaction of Cp*TiCl3 with LiN(2,6-
Me2C6H3)(SitBuMe2) under analogous conditions for 8a
(toluene reflux for 3 days) failed, and Cp*TiCl3 was
recovered instead.
type Cp′TiCl2(NR2),34-36 especially for preparing Cp*Ti-
Cl2(NiPr2),35 although the reaction was complete at room
temperature in the reported case. Furthermore, the
attempt of a reaction in Et2O at room temperature,
which has been a known method for the synthesis of
the analogous zirconium/hafnium complex Cp*MCl2-
[N(2,6-iPr2C6H3)(SiMe3)] (M ) Zr, Hf),12 was not suc-
cessful and Cp*TiCl3 was thus recovered. On the other
hand, the analogous zirconium complex Cp*ZrCl2[N(2,6-
Me2C6H3)(SiMe3)] (9a ) could be isolated in high yield
according to a previous report on preparing Cp*ZrCl2-
[N(2,6-iPr2C6H3)(SiMe3)].12 This is an interesting con-
trast between titanium and zirconium/hafnium com-
plexes of this type. In addition, Cp*TiCl3 was recovered
as the sole isolated compound from the reaction mixture
if reactions of Cp*TiCl3 with HN(2,6-Me2C6H3)(SiMe3)
in place of the lithium salt under various conditions
were attempted (Scheme 2). 8a could be identified by
1H and 13C NMR and elemental analysis.
Although the reaction under reflux conditions of
toluene was absolutely necessary to prepare 8a , (1,3-
Me2C5H3)TiCl2[N(2,6-Me2C6H3)(SiMe3)] (8b) could be
isolated in high yield by a similar reaction at 50 °C for
12 h after stirring the reaction mixture at room tem-
perature. In addition, CpTiCl2[N(2,6-Me2C6H3)(SiMe3)]
(8c), and CpTiCl2[N(2,6-Me2C6H3)(SitBuMe2)] (8d ) could
also be isolated in high yields by the reaction of CpTiCl3
with LiN(2,6-Me2C6H3)(SiMe3) and LiN(2,6-Me2C6H3)(Sit-
BuMe2), respectively, in toluene at room temperature.
The formation of (bridged or monodentate) imido de-
rivatives (e.g. CpTiCl(dN-2,6-Me2C6H3)) was not ob-
served under these conditions. These compounds were
1
also identified by H and 13C NMR spectra and elemen-
tal analyses.
2. Cr ysta l Str u ctu r e of (1,3-Me2C5H3)TiCl2[N(2,6-
Me2C6H3)(SiMe3)] (8b). Since attempts to prepare
Cp*TiCl2[N(2,6-iPr2C6H3)(SiMe3)] and/or Cp*TiCl2[N(2,6-
Me2C6H3)(SitBuMe2)] were not successful, even though
the analogous zirconium complex Cp*ZrCl2[N(2,6-i-
Pr2C6H3)(SiMe3)] was easily prepared in diethyl ether
under mild conditions, the structure determination for
the titanium complexes of this type by X-ray crystal-
lography was thus explored to observe the difference
among these complexes. Yellow prismatic microcrystals
were grown from the concentrated hot hexane solution
containing 8b by gradual cooling upon standing in the
drybox, and the structure could be determined if the
measurement was done at -30 °C. The attempt at room
temperature failed due to the gradual decomposition of
the crystal of 8b during the analysis run.
It turned out that 8a was thermally stable under
refluxing conditions in toluene for longer than 12 h, and
elimination of Me3SiCl was not observed under these
conditions. This is a remarkable contrast to the fact that
the reaction of CpTiCl3 with Me3SiN(H)Ph at room
temperature gave CpTiCl2N(H)Ph quantitatively, ac-
companying the elimination of Me3SiCl, then afforded
the imido-bridged dimer [CpTiCl]2(µ-PhN)2 upon heat-
ing, as shown in Scheme 1.32 The observed difference
might be explained by the steric bulk of the substituents
on the anilide group at the 2,6-positions that would
disturb the elimination of Me3SiCl.
The reaction of Cp*TiCl3 with LiN(2,6-iPr2C6H3)-
(SiMe3) in place of LiN(2,6-Me2C6H3)(SiMe3) was at-
The molecular structure of 8b is shown in Figure 1,
and selected bond distances and angles are summarized
in Table 1. The X-ray structure of 8b shows it to have
a tetrahedral geometry around the titanium metal
center, and remarkable differences in the structural
1
tempted under the same conditions for 8a , but the H
NMR spectrum for the reaction mixture after removal
of the solvent (which was then quickly washed with cold
hexane and dried in vacuo) showed the starting com-
Sch em e 3

(Anilide)(cyclopentadienyl)titanium(IV) Complexes
Organometallics, Vol. 21, No. 14, 2002 3045
F igu r e 1. Ortep drawings for (1,3-Me2C5H3)TiCl2[N(2,6-Me2C6H3)(SiMe3)] (8b). Thermal ellipsoids are drawn at the 50%
probability level, and hydrogen atoms are omitted for clarity.
Ta ble 1. Selected Bon d Dista n ces (Å) a n d Bon d
An gles (d eg) for
group. The observed value was shorter than the esti-
mated value (2.02 Å) for a titanium-nitrogen single
bond according to Pauling’s covalent radii38 and was
consistent with the presence of a titanium-nitrogen
double bond. No distinct differences were observed for
N-C (in phenyl) and N-Si bond distances between
these complexes. This structural result clearly explains
the reason it is difficult to prepare Cp*TiCl2[N(2,6-i-
Pr2C6H3)(SiMe3)], because the desired complex was
sterically hindered in the case of titanium.
(1,3-Me2C5H3)TiCl2[N(2,6-Me2C6H3)(SiMe3)] (8b)a
Bond Distances
Ti-Cl(1)
2.2770(9) Ti-Cl(2)
2.2662(9)
2.387(3)
2.326(3)
Ti-N(1)
1.898(2)
2.307(2)
1.806(2)
Ti-C(1) in Cp
Ti-C(3) in Cp
Ti-C(2) (Cp)
Si(1)-N(1)
Si(1)-C(16) (SiMe3) 1.830(5)
C(1)-C(2)
N(1)-C(8) (phenyl) 1.442(3)
1.402(4)
C(1)-C(5)
1.417(5)
Bond Angles
Cl(1)-Ti-Cl(2)
Cl(1)-Ti-C(1)
Cl(2)-Ti-N(1)
N(1)-Si(1)-C(17)
103.25(4) Cl(1)-Ti-N(1)
83.63(8) Cl(1)-Ti-C(2)
105.17(7)
108.14(9)
3. E t h ylen e P olym er iza t ion b y t h e 8- a n d
9-MAO Ca ta lyst System s. Ethylene polymerization
by 8a was conducted in toluene (ethylene at 6 atm) by
using a 100 mL autoclave. MAO white solid, which was
prepared by removing toluene and AlMe3 contaminated
in the commercially available MAO (PMAO-S, Tosoh
Finechem Co.), was chosen as the cocatalyst, because
this MAO was effective in preparing ethylene/R-olefin
copolymers with narrow molecular weight distributions
as well as with relatively high molecular weights if our
Cp′-aryloxy titanium species and [Me2Si(C5Me4)(NtBu)]-
TiCl2 were employed as the catalyst precursors.5,8-9 The
results are summarized in Table 2.
It turned out that 8a exhibited high catalytic activity
for ethylene polymerization and that the activity could
be optimized by varying the Al/Ti molar ratio. The
activity was, however, very sensitive to the polymeri-
zation temperature, and the value decreased at both 40
and 0 °C. The decrease in the activity at 40 °C would
be probably due to the partial decomposition of catalyti-
cally active species, because a lower activity was ob-
served if the polymerization was carried out at 60 °C
(run 9). A decrease in the activity was, on the other
hand, not observed at 0 °C after 60 min (runs 6 and 7).
The polymerization with an analogous zirconium com-
plex (9a ) was also carried out; the optimized catalytic
activity was lower than that by 8a , and a significant
decrease in the activity was observed at 40 °C. Since
8a itself is stable under reflux conditions in toluene as
described above, one probable reason for the decrease
105.07(7) N(1)-Si(1)-C(16) 111.2(2)
114.6(2)
N(1)-Si(1)-C(18) 110.6(2)
C(16)-N(1)-C(17) 106.8(4)
Ti-N(1)-Si(1)
Ti-C(2)-C(1)
Ti-C(3)-C(4)
120.6(1)
75.8(2)
76.0(2)
Ti-N(1)-C(8)
Ti-C(2)-C(3)
111.6(2)
73.2(1)
a
For detailed conditions and collected data, see the Supporting
Information.
features compared tothehafnium complexCp*HfCl2[N(2,6-
iPr2C6H3)(SiMe3)]12 were not observed. The position of
substituents around the nitrogen atom was also found
to be the same as that in the analogous hafnium
complex, the aryl group was positioned close to the
cyclopentadienyl group, and a plane consisting of ni-
trogen and the three substituents (Ti, Si in SiMe3, and
carbon atoms in the aryl groups) is placed perpendicular
to the plane of the cyclopentadienyl ring. The Ti-N bond
distance (1.90 Å) in 8b was somewhat shorter than that
in hafnium (2.05 Å), and the Ti-Cl bond distances
(2.27-2.28 Å) were somewhat shorter than those in
hafnium (2.36-2.38 Å). The observed Ti-N bond dis-
tance (1.90 Å) was the same as that in Cp*Ti(CH2Ph)2-
(NMe2) (1.89 Å)36 or somewhat longer than that in
CpTiCl2[N(SiMe3)2] (1.88 Å)37 or Cp*TiCl2(NiPr2) (1.87
Å),35 despite the electron-withdrawing nature of the aryl
(34) Mart´ın, A.; Mena, M.; Ye´lamos, C.; Serano, R. J . Organomet.
Chem. 1994, 467, 79.
(35) Pupi, R. M.; Coalter, J . N.; Petersen, J . L. J . Organomet. Chem.
1995, 497, 17.
(36) Sinnema, P.-J .; Spaniol, T. P.; Okuda, J . J . Organomet. Chem.
2000, 598, 179.
(37) Bai, Y.; Noltemeyer, M.; Roesky, H. W. Z. Anorg. Allg. Chem.
1991, 21, 595.
(38) Pauling, L. The Nature of the Chemical Bond, 3rd ed.; Cornell
University Press: Ithaca, NY, 1960.

3046 Organometallics, Vol. 21, No. 14, 2002
Nomura and Fujii
Ta ble 2. Eth ylen e P olym er iza tion by th e
Cp *MCl2[N(2,6-Me2C6H3)(SiMe3)] (M ) Ti (8a ), Zr
(9a ))-MAO Ca ta lyst System a
effect of the amide ligand on the activity would be thus
explained by the assumption that the stability of
catalytically active species, especially the stability of the
N-alkylsilyl bond in solution under these reaction
conditions,37 affects the observed catalytic activity.
The resultant polymer was linear in all cases con-
activityc/(kg
run cat. (amt/
temp/ time/ yield/ of PE/((mol of
no.
µmol)
Al/Tib
°C
min
mg
Ti) h))
1
2
3
4
5
6
7
5
8
8a (1.0)
8a (1.0)
8a (1.0)
8a (1.0)
8a (2.0)
8a (2.0)
8a (2.0)
8a (2.0)
8a (2.0)
8a (2.0)
9a (3.0)
9a (1.0)
9a (1.0)
1000
2000
3000
5000
1000
1000
1000
1000
1000
1000
1000
3000
3000
25
25
25
25
25
0
30
30
30
30
10
10
60
10
10
10
30
30
30
207
361
435
451
360
23
173
360
113
78
414 (69.0)
722 (120)
870 (145)
902 (150)
1080 (180)
69 (11.5)
87 (14.5)
1080 (180)
338 (56.3)
235 (39.2)
478 (79.7)
637 (106)
40 (6.7)
1
firmed by H and 13C NMR, but the molecular weight
for the resultant polyethylene depended upon the sub-
stituent on the cyclopentadienyl group. The resultant
polymer from 8a possessed poor solubility in hot o-
dichlorobenzene and so was not suited for a conventional
GPC analysis (in o-dichorobenzene at 140 °C), but the
polymer was completely soluble in 1,3,5-trichloroben-
zene at 150 °C.40 This result suggests that the resultant
polymer from 8a possessed extremely high molecular
weight. On the other hand, the resultant polymer from
8b possessed relatively low molecular weight with
unimodal polydispersity. Moreover, the resultant poly-
mer from the Cp analogues 8c and 8d gave a mixture
consisting of polyethylene with multimodal molecular
weight distributions (insoluble in acidified ethanol) and
oligomeric oil (soluble in acidified ethanol and could be
extracted with chloroform). From the analysis of the GC
chromatogram as well as GC-MS, these oligomers
consisted of linear C14-C30 hydrocarbons. In addition,
0
25
40
60
25
25
40
9
10
11
12
717
319
200
a
Polymerization conditions: toluene 30 mL, d-MAO (prepared
by removing toluene and AlMe3 from commercially available
b
MAO), ethylene 6 atm. Molar ratio of Al/Ti. c In parentheses, the
activity is displayed as kg of PE/((mol of Ti) h atm).
in the activity would be the thermal stability of the
catalytically active species under these polymerization
conditions, containing an excess amount of MAO.
Table 3 summarizes results for the ethylene polym-
erization with various Cp′-anilide titanium complexes.
The observed catalytic activity with a series of Cp′TiCl2-
[N(2,6-Me2C6H3)(SiMe3)] complexes at 25 °C increased
in the order (MAO cocatalyst in toluene) Cp′ ) Cp* (8a ,
902 kg of PE/((mol of Ti) h)) > 1,3-Me2C5H3 (8b, 104 kg
of PE/((mol of Ti) h)), Cp (8c, 113 kg of PE/((mol of Ti)
h)). On the basis of these results, it would be suggested
that the introduction of an electron-donating group into
the cyclopentadienyl ring increases the catalytic activity
as previously reported in Cp′-aryloxy titanium com-
plexes,5 although there are several factors such as the
stability of the catalytically active species and/or the
percentage of the actual catalytically active species,
because these complexes are used as the catalyst
precursor and do not act as the catalyst itself. The
activity by CpTiCl2[N(2,6-Me2C6H3)(SitBuMe2)] (8d )
seemed somewhat higher than CpTiCl2[N(2,6-Me2C6H3)-
(SiMe3)] (8c) under the same conditions, and this trend
is similar to that observed for ethylene polymerization
with a series of [1,8-C10H6(NR)2]TiCl2 (R ) SiMe3, Sit-
BuMe2, SiiPr3)-MAO catalyst systems.39 The observed
1
the H NMR spectrum reveals that the resultant oligo-
mer consisted of a mixture of linear alkanes (71.5 mol
%) and olefins (28.5 mol %) (Figure 2b). Olefinic double
1
bonds were also observed by the H NMR spectrum for
the ethanol-insoluble sample (Figure 2a). One probable
assumption for producing a mixture of oligomer and
high-molecular-weight polyethylene by 8c,d would be
that several catalytically active species were present
under these polymerization conditions. Although the
polymerization by 8c,d afforded a mixture of low- and
high-molecular-weight products, these results clearly
suggest that the nature of the cyclopentadienyl frag-
ment directly affects the molecular weight in these
catalyses.
4. P olym er iza tion of P r op ylen e a n d 1-Hexen e by
th e 8a -MAO Ca ta lyst System . Table 4 summarizes
the results for propylene polymerization with the 8a -
MAO catalyst system. The catalytic activity increased
at the lower temperature of 0 °C, and the activity also
increased at higher propylene pressure. The resulting
polymer possessed extremely high molecular weight
Ta ble 3. Eth ylen e P olym er iza tion by th e Cp ′TiCl2[N(2,6-Me2C6H3)(R)]-MAO Ca ta lyst System (R ) SiMe3
a n d Cp ′ ) Cp * (8a ), 1,3-Me2C5H3 (8b), Cp (8c); R ) SitBu Me2 a n d Cp ′ ) Cp (8d ))a
e
e
run no.
cat. (amt/µmol)
Al/Tib
temp/°C
yieldc/mg
activityd/(kg of PE/((mol of Ti) h))
10-4Mw
Mw/Mn
3
4
8
13
14
15
16
17
18
19
8a (1.0)
8a (1.0)
8a (2.0)
8b (10.0)
8b (10.0)
8b (10.0)
8c (10.0)
8c (10.0)
8d (10.0)
8d (10.0)
3000
5000
1000
500
500
500
500
500
500
500
25
25
40
25
25
40
25
25
25
40
435
451
113
518
484
140
567 (373)
525 (335)
684 (477)
257 (183)
870 (145)
902 (150)
338 (56.3)
104 (17.3)
97 (16.2)
28 (4.7)
113 (18.8)
105 (17.5)
137 (22.8)
51 (8.5)
insolublef
insolublef
insolublef
0.19
0.19
0.18
34.2h
63.9h
2.00
2.00
2.01g
198
297
28.4i
96.1
a
Polymerization conditions: toluene 30 mL, d-MAO (prepared by removing toluene and AlMe3 from commercially available MAO),
ethylene 6 atm, 25 °C, 30 min (run 8, 10 min). Molar ratio of Al/Ti. c The yield of low-molecular-weight oligomer oil is given in parentheses
b
d
(soluble in acidified ethanol and extracted with chloroform; see the Experimental Section). In parentheses, the activity is displayed as
kg of PE/((mol of Ti) h atm). e GPC data (acidified ethanol-insoluble portion) in o-dichlorobenzene vs polystyrene standard. f The resulting
g
polyethylene was insoluble in hot o-dichlorobenzene (but soluble in 1,3,5-trichlorobenzene at 145-150 °C). High-molecular-weight PE
h
i
was also observed in a trace amount. Mixture of high- and low-molecular-weight polymers. Bimodal molecular weight distribution
consisted of Mw ) 5.01 × 105, 2.19 × 103.

(Anilide)(cyclopentadienyl)titanium(IV) Complexes
Organometallics, Vol. 21, No. 14, 2002 3047
Ta ble 5. P olym er iza tion of 1-Hexen e by th e
Cp ′TiCl2[N(2,6-Me2C6H3)(R)]-MAO Ca ta lyst System
(R ) SiMe3 a n d Cp ′ ) Cp * (8a ), 1,3-Me2C5H3 (8b),
Cp (8c); R ) SitBu Me2 a n d Cp ′ ) Cp (8d ))a
activity/(kg
run
no.
complex
(amt/µmol)
yield/
mg
of PH/((mol
of Ti) h)
Mw/
Mn
b
b
Mn
26
27
28
29
8a (20.0)
8b (10.0)
8c (10.0)
8d (10.0)
121.5
14
12
6.08
1.4
1.2
967c
932d
965e
769f
1.18
1.07
1.10
1.09
36
3.6
a
Polymerization conditions: catalyst 2.0 µmol/mL of 1-hexene,
1-hexene 5 mL (run 26, 10 mL), 60 min, room temperature, d-MAO
(prepared by removing toluene and AlMe3 from commercially
b
available MAO), molar ratio of Al/Ti 500. GPC data in THF vs
polystyrene standard. c High-molecular-weight PH was also ob-
d
served in a small amount. Mn ) 4.61 × 104, Mw/Mn ) 1.80. High-
molecular-weight PH was also observed in a small amount. Mn
)
2.34 × 104, Mw/Mn ) 1.32. e High-molecular-weight PH was also
observed in a small amount. Mn ) 8.38 × 105, Mw/Mn ) 1.53.
f High-molecular-weight 1-hexane oligomer was also observed in
a small amount. Mn ) 4.82 × 103, Mw/Mn ) 1.15.
ethylene polymerization by 8a , in which extremely high
molecular weight polyethylene could be prepared. On
the basis of the 13C NMR spectrum (in C6D6/1,3,5-
trichlorobenzene), the resultant polypropylene possessed
regioregularity but did not have stereoregularity, and
the atactic polymer was thus obtained.41
Polymerization of 1-hexene was also employed, and
the results are summarized in Table 5. The observed
catalytic activity by 8a was low (6.08 kg of PH/((mol of
Ti) h)), and lower catalytic activities were found for 8b-
d . In addition, the resultant poly(1-hexene)s possessed
low molecular weights with narrow molecular weight
distributions in all cases. The results observed here are
in interesting contrast with those using the Cp*TiCl2(O-
2,6-iPr2C6H3)-MAO catalyst system, which exhibited
remarkably high catalytic activity and afforded high-
molecular-weight poly(1-hexene) with narrow molecular
weight distribution (Mn ) 69.5 × 104, Mw/Mn ) 1.62)
under similar conditions.6 As expected, the resultant
polymer does not have a stereoregularity.41
F igu r e 2. 1H NMR spectra (in CDCl3) for polyethylene
prepared by the CpTiCl2[N(2,6-Me2C6H3)(SiMe3)] (8c)-
MAO catalyst system (Table 3, run 17): (a) EtOH-insoluble
fractio; (b) EtOH-soluble fraction.
We have shown that (anilide)(cyclopentadienyl)tita-
nium(IV) complexes of the type Cp′TiCl2[N(2,6-Me2C6H3)-
(SiMe3)] should be candidates for effective catalyst
precursors especially for ethylene polymerization. How-
ever, we do not have an exact reason why a significant
difference (catalytic activity, molecular weight) can be
observed, especially in 1-hexene polymerization between
Cp′-aryloxy and Cp′-anilide titanium catalyst systems.
Although our present attempts to find titanium cata-
lysts more active than Cp*TiCl2(O-2,6-iPr2C6H3) for
olefin polymerization were not very successful, the facts
observed here should be very important for designing
effective catalyst precursors for precise olefin polymer-
ization. We are doing more research with these cata-
lysts, especially for ethylene-based copolymerization,
and these results will be introduced soon.
Ta ble 4. P olym er iza tion of P r op ylen e by th e
Cp *TiCl2[N(2,6-Me2C6H3)(SiMe3)] (8a )-MAO
Ca ta lyst System a
propylene
press./
atm
activityb/(kg
temp/ yield/ of PP/((mol
run
no.
Mw/
Mn
c
c
°C
mg
41.8 13.9 (2.78)
26.5 8.83 (1.77)
200.4 51.0 (7.29)
of Ti) h)))
10-4Mw
20
21
22
23
24
25
5
5
7
7
7
7
0
40
0
25
25
40
91.3
185d
1.77
53
51
12.3
17.7 (2.53)
17.0 (2.43)
4.10 (0.59)
1.40d
a
Polymerization conditions: 8a 6.0 µmol, toluene 30 mL,
d-MAO (prepared by removing toluene and AlMe3 from com-
b
mercially available MAO) 3.0 mmol (Al/Ti ) 500), 30 min. In
parentheses, the activity is displayed as kg of PP/((mol of Ti) h
atm). c GPC data in o-dichlorobenzene vs polystyrene standard.
d
Low-molecular-weight polypropylene was observed: Mn ) 7.08
× 104, Mw/Mn ) 1.60, Mn ) 5.16 × 103, Mw/Mn ) 1.09.
(39) Nomura, K.; Naga, N.; Takaoki, K. Macromolecules 1998, 31,
8009.
(40) K.N. expresses his thanks to Mr. G. Uematsu (Tosoh Co.) for
helpful comments concerning the analysis of polyethylene prepared
by 8a .
with narrow molecular weight distributions (Mw
)
(91.3-185) × 104, Mw/Mn ) 1.40-1.77), and these
(41) For the 13C NMR spectrum (in CDCl3), see the Supporting
Information.
results were in good correspondence with those for

3048 Organometallics, Vol. 21, No. 14, 2002
Nomura and Fujii
Syn th esis of (1,3-Me2C5H3)TiCl2[N(2,6-Me2C6H3)(SiMe3)]
(8b). Into a sealed tube equipped with a Kontes three-way bulb
was added (1,3-Me2C5H3)TiCl3 (100 mg, 0.404 mmol) in toluene
(10 mL) in the drybox. LiN(2,6-Me2C6H3)(SiMe3) (1.0 equiv
with respect to titanium) was then added at -30 °C, and the
reaction mixture was warmed slowly to room temperature and
placed into an oil bath preheated at 50 °C. After the reaction
(12 h), the mixture was filtered through a Celite pad, the
solution was evaporated in vacuo, and the resultant solid was
extracted with n-hexane (ca. 10 mL) at room temperature. The
extract was concentrated to half-volume and placed in the
freezer (-30 °C). The pale yellow microcrystals were collected
as the first crop (105 mg) from the chilled solution. The second
crop (30 mg) was collected from the chilled solution of the
concentrated mother liquor. Yield: 83% (135 mg). 1H NMR
(CDCl3): δ 7.07 (d, J ) 7.2 Hz, 2H, phenyl), 6.94 (t, J ) 7.4
Hz, 1H, phenyl), 6.02 (s, 1H, Cp), 5.49 (s, 2H, Cp), 2.26 (s, 6H,
CH3-phenyl), 2.17 (s, 15H, C5Me5), 0.28 (s, 9H, SiMe3). 13C
NMR (CDCl3): δ 159.3, 136.6, 128.4, 124.5, 123.0, 121.1, 20.6,
17.5, 2.8. Anal. Calcd. for C18H27Cl2NSiTi: C, 53.48; H, 6.73;
N, 3.46. Found: C, 53.16; H, 6.68; N, 3.63. (1,3-Me2C5H3)TiCl3
was prepared according to the procedures given in our previous
paper.5
Exp er im en ta l Section
Gen er a l P r oced u r es. All experiments were carried out
under a nitrogen atmosphere in a Vacuum Atmospheres
drybox or using standard Schlenk techniques unless otherwise
specified. All chemicals used were reagent grade and were
purified by the standard purification procedures. Toluene for
polymerization was distilled in the presence of sodium and
benzophenone under a nitrogen atmosphere and was stored
in a Schlenk tube in the drybox. Ethylene for polymerization
was of polymerization grade (purity >99.9%, Sumitomo Seika
Co. Ltd) and was used as received. Propylene for polymeriza-
tion was of polymerization grade (Takachiho Co. Ltd.) and was
used as received. 1-Hexene of reagent grade (Wako Chemical
Co. Ltd.) was stored in the drybox in the presence of molecular
sieves and was used without further purification. Toluene and
AlMe3 in the commercially available methylaluminoxane
(PMAO-S, 9.5 wt % (Al) toluene solution, Tosoh Finechem Co.)
were removed and dried in vacuo in the drybox and used as
the white solid.
The molecular weight and molecular weight distribution of
the resultant polymers were measured by gel permeation
chromatography (Tosoh HLC-8121GPC/HT) with a polystyrene
gel column (TSK gel GMHHR-H HT x 2) at 140 °C using
o-dichlorobenzene containing 0.05 wt/v % 2,6-di-tert-butyl-p-
cresol as solvent. The molecular weight was calculated by a
standard procedure based on calibration with standard poly-
styrene samples.
Syn th esis of Cp TiCl2[N(2,6-Me2C6H3)(SiMe3)] (8c). Into
a round-bottom flask containing CpTiCl3 (100 mg, 0.456 mmol)
in toluene (10 mL) was added LiN(2,6-Me2C6H3)(SiMe3) (91
mg, 0.456 mmol) at -30 °C. The stirred reaction mixture was
warmed slowly to room temperature, and the mixture was then
stirred for 12 h. The solution was then filtered through a Celite
pad, and the filtrate was placed in a rotary evaporator to
remove toluene. The resultant solid was extracted with n-
hexane, and the chilled (-30 °C) concentrated solution gave
the first crop as yellow needles. Yield: 126 mg (73%). 1H NMR
(CDCl3): δ 7.08 (d, J ) 7.2 Hz, 2H, phenyl), 6.95 (t, J ) 7.6
Hz, 1H, phenyl), 6.30 (s, 5H, Cp), 2.16 (s, 6H, CH3-phenyl),
0.31 (s, 9H, SiMe3). 13C NMR (CDCl3): δ 160.0, 128.5, 128.1,
124.9, 121.1, 20.6, 2.7. Anal. Calcd for C16H23Cl2NSiTi: C,
51.08; H, 6.16; N, 3.72. Found: C, 51.0; H, 5.96; N, 3.59.
Syn th esis of Cp TiCl2[N(2,6-Me2C6H3)(SitBu Me2)] (8d ).
The synthetic procedure for preparing 8d was the same as that
for 8c from CpTiCl3 (266 mg, 0.752 mmol), except that LiN-
(2,6-Me2C6H3)(SitBuMe2) (1.0 equiv with respect to titanium;
320 mg was used in this case) was added in place of LiN(2,6-
Me2C6H3)(SiMe3). Orange microcrystals were collected from the
chilled hexane solution. Yield: 81% (341 mg). 1H NMR
(CDCl3): δ 7.06 (d, J ) 7.2 Hz, 2H, phenyl), 6.96 (t, J ) 7.6
Hz, 1H, phenyl), 6.25 (s, 5H, Cp), 2.23 (s, 6H, CH3-phenyl),
All 1H and 13C NMR spectra were recorded on a J EOL J NM-
LA400 spectrometer (399.65 MHz, 1H). All deuterated NMR
solvents were stored over molecular sieves under a nitrogen
atmosphere, and all chemical shifts are given in ppm and are
referenced to Me4Si. All spectra were obtained in the solvent
indicated at 25 °C unless otherwise noted. 13C NMR spectra
for polyethylene and polypropylene were recorded on a J EOL
J NM-LA400 spectrometer (100.40 MHz, 13C) with proton
decoupling. The pulse interval was 5.2 s, the acquisition time
was 0.8 s, the pulse angle was 90°, and the number of
transients accumulated was ca. 10 000. The polymer solution
for polyethylene prepared by the 8a -MAO catalyst system was
prepared by dissolving the polymers in a mixed solution of
1,3,5-trichlorobenzene and benzene-d6 (90/10 wt), and the
spectrum was measured at 130 °C. The samples for polyeth-
ylene prepared by the 8c-MAO catalyst system were mea-
sured at room temperature in CDCl3. The sample for polypro-
pylene prepared by the 8a -MAO catalyst system was also
measured at room temperature in CDCl3. Molecular weights
and molecular weight distributions for the resultant polypro-
pylene and poly(1-hexene) were measured by GPC (Shimazu
SCL-10A with RID-10A detector, ShimPAC GPC-806, 804, and
802 columns) in THF vs polystyrene standard.
0.74 (s, 6H, SiMe2 Bu), 0.31 (s, 9H, SiMe2 Bu). 13C NMR
(CDCl3): δ 158.9, 128.7, 128.4, 125.3, 121.6, 27.5, 22.8, 21.9,
0.3. Anal. Calcd for C16H23Cl2NSiTi: C, 54.56; H, 6.99; N, 3.35.
Found: C, 54.70; H, 6.85; N, 3.41.
t
t
Syn th esis of Cp *Zr Cl2[N(2,6-Me2C6H3)(SiMe3)] (9a ). The
synthesis of 9a was according to the analogous procedure for
the synthesis of Cp*ZrCl2[N(2,6-iPr2C6H3)(SiMe3)] reported by
Roesky.12 A round-bottom flask containing Cp*ZrCl3 (250 mg,
0.751 mmol) was cooled to -30 °C. LiN(2.6-Me2C6H3)(SiMe3)
(150 mg, 0.752 mmol) was then added and the reaction mixture
was warmed to room temperature, and the solution was stirred
for 24 h. The solvent was then removed in vacuo after the
reaction, and the resultant solid was extracted with hexane
at room temperature. The extract was concentrated to ca. 3
mL and was placed in the freezer (-30 °C). The pale yellow
microcrystals were collected as the first crop (288 mg) from
Syn th esis of Cp *TiCl2[N(2,6-Me2C6H3)(SiMe3)] (8a ). Into
a sealed tube equipped with a Kontes three-way bulb was
added Cp*TiCl3 (500 mg, 1.727 mmol) in toluene (30 mL) in
the drybox. LiN(2,6-Me2C6H3)(SiMe3) (344 mg, 1.727 mmol)
was then added at -30 °C, and the reaction mixture was
warmed slowly to room temperature and was placed into an
oil bath preheated at 110 °C. After the reaction (12 h), the
mixture was filtered through a Celite pad, the solution was
evaporated in vacuo, and the resultant solid was extracted
with n-hexane (ca. 80 mL) at room temperature. The extract
was concentrated and placed in the freezer (-30 °C). The pale
yellow microcrystals were collected as the first crop (602 mg)
from the chilled solution. Yield: 78%. 1H NMR (CDCl3): δ 7.01
(d, J ) 7.6 Hz, 2H, phenyl), 6.88 (t, J ) 8.0 Hz, 1H, phenyl),
2.12 (s, 6H, CH3-phenyl), 1.86 (s, 15H, C5Me5), 0.22 (s, 9H,
SiMe3). 13C NMR (CDCl3): δ 155.7, 131.9, 130.2, 128.2, 124.1,
1
the chilled solution. Yield: 78%. H NMR (CDCl3): δ 7.02 (d,
J ) 7.2 Hz, 2H, phenyl), 6.84 (t, J ) 7.4 Hz, 1H, phenyl), 2.17
(s, 6H, CH3-phenyl), 1.82 (s, 15H, C5Me5), 0.21 (s, 9H, SiMe3).
13C NMR (CDCl3): δ 150.0, 131.8, 128.4, 126.5, 123.1, 21.2
(Cp*), 11.6 (CH3-Ph), 3.0 (SiMe3).
21.3 (Cp*), 12.9 (CH3-Ph), 3.7 (SiMe3). Anal. Calcd for C21H33
Cl2NSiTi: C, 56.51; H, 7.45; N, 3.14. Found (1): C, 57.05; H,
7.70; N, 3.30. Found (2): C, 57.06; H, 7.35; N, 3.51.
-
P olym er iza tion P r oced u r es. Ethylene polymerizations
were conducted in a 100 mL stainless steel autoclave. The
typical reaction procedure (run 4, Table 2) is as follows.

(Anilide)(cyclopentadienyl)titanium(IV) Complexes
Organometallics, Vol. 21, No. 14, 2002 3049
Ta ble 6. Cr ysta l a n d Da ta Collection P a r a m eter s
for (1,3-Me2C5H3)TiCl2[N(2,6-Me2C6H3)(SiMe3)] (8b)a
Toluene (29.5 mL) and d-MAO solid (290 mg, prepared from
ordinary MAO (Tosoh Finechem Co. PMAO-S) by removing
toluene and AlMe3) were added into the autoclave in the
drybox. The reaction apparatus was then filled with ethylene
(1 atm) and the autoclave was placed into an oil bath. 8a (1.0
µmol) in toluene (0.5 mL) was then added into the autoclave,
the reaction apparatus was immediately pressurized to 5 atm,
and the mixture was magnetically stirred for 30 min. After
the above procedure, the ethylene that remained was purged,
and the mixture was then poured into EtOH (50 mL) contain-
ing HCl (5 mL). The resultant polymer (white precipitate) was
collected on a filter paper by filtration, and was adequately
washed with EtOH and water and then dried in vacuo for
several hours. In polymerization by 8c,d (runs 16-19), the
EtOH solution was then added to chloroform. The chloroform
extract was then washed with water and dried over Na2SO4.
The solution was placed in a rotary evaporator, and the low-
boiling compounds such as CHCl3 and toluene were removed
in vacuo. Polymerization of propylene was also performed in
the same manner.
Polymerization of 1-hexene was performed as follows: 1-hex-
ene (5 mL) and the prescribed amount of MAO were added to
a round-bottom flask (25 mL) connected to three-way valves
under N2, and the polymerization was started by the addition
of a toluene solution (2.5 mL) containing the catalyst (5.0
µmol). The reaction mixture was stirred for 30 min at room
temperature, and the polymerization was terminated with the
addition of EtOH. The reaction product was extracted with
CHCl3, and the extract was washed with HCl aqueous solution
and then rinsed with water. The chloroform extract was dried
over Na2SO4, and the chloroform and 1-hexene that remained
were then removed in vacuo.
Cr ysta llogr a p h ic An a lysis for 8b. The yellow prismatic
microcrystal was grown from the concentrated hot hexane
solution containing 8b upon standing at room temperature in
the drybox, and the structure could be determined if the
measurement was done at -30 °C. All measurements were
made on a Rigaku RAXIS-RAPID imaging plate diffractometer
with graphite-monochromated Mo KR radiation. The selected
crystal collection parameters are listed in Table 6. All struc-
tures were solved by direct methods and expanded using
Fourier techniques.42 The non-hydrogen atoms were refined
anisotropically. Hydrogen atoms were included but not refined.
All calculations were performed using the teXsan43 crystal-
lographic software package of Molecular Structure Corp.
Detailed results are described in the Supporting Information.
formula
fw
C18H27Cl2NSiTi
404.31
habits
cryst size (mm)
cryst syst
yellow, prism
0.80 × 0.80 × 0.33
triclinic
space group
a (Å)
b (Å)
c (Å)
P1h (No. 2)
8.887(1)
10.298(2)
13.081(1)
94.823(6)
101.545(4)
114.807(6)
1045.5(2)
3
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
Dcalcd (g/cm3)
1.926
F000
636.00
temp (K)
243
λ(Mo KR) (Å)
0.71069
2θ range (deg)
4.4-54.7
9207; 4662
0.056
no. of rflns measd: total; unique
Rint
no. of observns (I > -10.00δ(I))
no. of variables
4662
208
residuals: R1; wR2
GOF
0.062; 0.172
2.21
0.40 (-0.47)
max (min) peak in final diff map (e/Å3)
a
Conditions: diffractometer, Rigaku RAXIS-RAPID imaging
plate; structure solution, direct methods; refinement, full-matrix
2
least squares; function minimized, ∑w(Fo - Fc2)2; least-squares
weights, w ) 1/δ2(Fo2); p factor, 0.05.
our sincere thanks to Prof. K. Koga (Nara Institute of
Science and Technology, NAIST) for helpful discussions,
to Prof. A. Nakamura (OM Research, emeritus Professor
of Osaka University) for his helpful comments, and to
Dr. K. Tsutsumi (NAIST) for assisting us with X-ray
crystallography. K.N. expresses his heartfelt thanks to
Tosoh Finechem Co. for donating MAO (PMAO-S) and
to Asahi Kasei Co. Ltd. for GPC analysis of polyethyl-
ene. K.N. thanks Prof. M. Hirano (Tokyo University
A&T) for helpful comments. We also acknowledge Prof.
Y. Imanishi (emeritus Professor of NAIST) for his
comments on this project.
Su p p or tin g In for m a tion Ava ila ble: Figures giving the
13C NMR spectrum (in CDCl3) for polypropylene prepared by
the 8a -MAO catalyst system (Table 3, run 17) and selected
GPC traces for polyethylene summarized in Table 3 and tables
giving detailed crystallographic analysis data for 8b. This
material is available free of charge via the Internet at
http://pubs.acs.org.
Ack n ow led gm en t. Part of this research was sup-
ported by a Grant-in-Aid for Encouragement of Young
Scientists from the Ministry of Education, Science,
Sports and Culture of J apan (No. 13750727). We express
(42) DIRDIF94: Beurskens, P. T.; Admiraal, G.; Beurskens, G.;
Bosman, W. P.; de Delder, R.; Israel, R.; Smits, J . M. M. The DIRDIF94
Program System, Technical Report of the Crystallography Laboratory;
University of Nijmegen, Nijmegen, The Netherlands, 1994.
OM020179H
(43) teXsan: Crystal Structure Analysis Package; Molecular Struc-
ture Corp., The Woodlands, TX, 1985 and 1999.