[1-(2-Phenylethyl)-2,3,4,5-tetramethylcyclopentadienyl]-titanium compounds. Synthesis and their use for the syndiospecific polymerization of styrene

Article abstract of DOI:10.1021/om960475s

A series of monocyclopentadienyltitanium complexes containing the 1-(2-phenylethyl)-2,3,4,5-tetramethylcyclopentadienyl ligand (C₅Me₄CH₂CH₂Ph) have been synthesized and characterized. The reaction of C₅Me₄(SiMe₃)CH₂CH₂Ph (2) with TiCl₄ was used to synthesized the trichloro complex (C₅Me₄CH₂CH₂Ph)TiCl₃ (3), the molecular structure of which was confirmed by an X-ray diffraction study. Compound 3 was further converted into (C₅Me₄CH₂CH₂Ph)TiMe₃ (4). Reaction of the latter with 1 equiv of [Ph₃C][B(C₆F₅)₄] was almost quantitative to give the cationic compound [(C₅Me₄CH₂CH₂Ph)TiMe ₂]⁺[B(C₆F₅)₄]^- (5). Complex 5 was thermally unstable in solution and very moisture sensitive. Compound 4 was readily hydrolyzed to [(C₅Me₄CH₂CH₂Ph)TiMe ₂M]₂(μ-O) (6) upon recrystallization in wet pentane. Structural data indicate intramolecular coordination of the phenyl group to titanium in compound 5, whereas there are no such indications for 3, 4, or 6. The catalytic performance for styrene polymerization of 3 activated with methylaluminoxane (MAO) has been compared with the nonsubstituted reference compound (C₅Me₅)TiCl₃ (7). Complex 5, prepared in situ by reacting 4 with [Ph₃C][B(C₆F₅)₄], has also been found to be active for the syndiospecific polymerization of styrene. The polymerization data for 3 and 5 lead to the tentative suggestion that the active species is in equilibrium between two states, one with and one without intramolecular phenyl coordination to Ti. These findings would be consistent with postulated multihapto coordination of styrene by both the vinylic double bond and the aromatic ring to the metal center during the catalytic process.

Full text of DOI:10.1021/om960475s

4944
Organometallics 1996, 15, 4944-4950
[1-(2-P h en yleth yl)-2,3,4,5-tetr a m eth ylcyclop en ta d ien yl]-
tita n iu m Com p ou n d s. Syn th esis a n d Th eir Use for th e
Syn d iosp ecific P olym er iza tion of Styr en e
J uan C. Flores,†,‡ J ohn S. Wood,† J ames C. W. Chien,*,† and Marvin D. Rausch*,†
Department of Chemistry and Department of Polymer Science and Engineering,
University of Massachusetts, Amherst, Massachusetts 01003, and Departamento de
Quı´mica Inorga´nica, Facultad de Ciencias, Universidad de Alcala´, Campus Universitario,
28871 Alcala´ de Henares, Spain
Received J une 12, 1996X
A series of monocyclopentadienyltitanium complexes containing the 1-(2-phenylethyl)-
2,3,4,5-tetramethylcyclopentadienyl ligand (C5Me4CH2CH2Ph) have been synthesized and
characterized. The reaction of C5Me4(SiMe3)CH2CH2Ph (2) with TiCl4 was used to
synthesized the trichloro complex (C5Me4CH2CH2Ph)TiCl3 (3), the molecular structure of
which was confirmed by an X-ray diffraction study. Compound 3 was further converted
into (C5Me4CH2CH2Ph)TiMe3 (4). Reaction of the latter with 1 equiv of [Ph3C][B(C6F5)4]
was almost quantitative to give the “cationic” compound [(C5Me4CH2CH2Ph)TiMe2]+[B(C6F5)4]-
(5). Complex 5 was thermally unstable in solution and very moisture sensitive. Compound
4 was readily hydrolyzed to [(C5Me4CH2CH2Ph)TiMe2]2(µ-O) (6) upon recrystallization in
wet pentane. Structural data indicate intramolecular coordination of the phenyl group to
titanium in compound 5, whereas there are no such indications for 3, 4, or 6. The catalytic
performance for styrene polymerization of 3 activated with methylaluminoxane (MAO) has
been compared with the nonsubstituted reference compound (C5Me5)TiCl3 (7). Complex 5,
prepared in situ by reacting 4 with [Ph3C][B(C6F5)4], has also been found to be active for the
syndiospecific polymerization of styrene. The polymerization data for 3 and 5 lead to the
tentative suggestion that the active species is in equilibrium between two states, one with
and one without intramolecular phenyl coordination to Ti. These findings would be consistent
with postulated multihapto coordination of styrene by both the vinylic double bond and the
aromatic ring to the metal center during the catalytic process.
In tr od u ction
been applied to group 4 monocyclopentadienyl com-
pounds and several “cationic” complexes of the types
[CpMR2]+ and [CpMR2L]+ have been reported.7 Some
of the complexes were successfully used for the syn-
diospecific polymerization of styrene and other R-ole-
fins.8 The formation of this type of active species by
the action of MAO on half-sandwich metallocenes is
anticipated, although other proposed species cannot be
ruled out.2b,2c,9 In compounds of the type [CpMR2L]+
(L ) η6-toluene, ηn-styrene, ηn-benzyl; M ) Ti, Zr, Hf),
Ishihara and co-workers found that organotitanium
compounds activated with methylaluminoxane (MAO)
catalyze syndiospecific polymerization of styrene at
temperatures above 25 °C.1 This finding, together with
other studies in this field, has led to the conclusion that
half-sandwich titanium chloride or alkoxide compounds
containing η5-C5H5, η5-C5Me5, η5-C5Me4H, or η5-C9H7
ligands are among the favored precursors.1-3 The
isolation of metallocenium species (Cp2M+R)4 by react-
ing alkylmetallocenes with a strong Lewis acidic salt
of a noncoordinating anion (e.g., [Ph3C]+[B(C6F5)4]-),
and their use in the polymerization of ethylene and
propylene,5 have led to the acceptance of a catalytically
active metallocenium species.4,6 This idea has recently
(5) (a) Chien, J . C. W.; Tsai, W.-M.; Rausch, M. D. J . Am. Chem.
Soc. 1991, 113, 8570. (b) Tsai, W.-M.; Rausch, M. D.; Chien, J . C. W.
Appl. Organomet. Chem. 1993, 7, 71. (c) Elder, M. J .; Razavi, A.; Ewen,
J . A. U.S. Patents 5,155,080 (Oct 13, 1992) and 5,225,500 (J uly 6, 1993)
(to Fina Technology, Inc.). (d) For a recent review see: Mo¨hring, P.
C.; Coville, N. J . J . Organomet. Chem. 1994, 479, 1.
(6) (a) Marks, T. J . Acc. Chem. Res. 1992, 25, 57. (b) Bochmann,
M.; Lancaster, S. J . Angew. Chem., Int. Ed. Engl. 1994, 33, 1634.
(7) (a) Gillis, D. J .; Tudoret, M.-J .; Baird, M. C. J . Am. Chem. Soc.
1993, 115, 2543. (b) Wang, Q.; Quyoum, R.; Gillis, D. J .; Tudoret, M.-
J .; J eremic, D.; Hunter, B. K.; Baird, M. C. Organometallics 1996, 15,
693. (c) Pellecchia, C.; Immirzi, A.; Zambelli, A. J . Organomet. Chem.
1994, 479, C9. (d) Pellecchia, C.; Immirzi, A.; Pappalardo, D.; Peluso,
A. Organometallics 1994, 13, 3773. (e) Pellecchia, C.; Immirzi, A.;
Grassi, A.; Zambelli, A. Organometallics 1993, 12, 4473. (f) Pellecchia,
C.; Grassi, A.; Immirzi, A. J . Am. Chem. Soc. 1993, 115, 1160. (g)
Lancaster, S. J .; Robinson, O. B.; Bochmann, M. Organometallics 1995,
14, 2456.
(8) (a) Reference 3c. (b) Pellecchia, C.; Longo, P.; Proto, A.; Zambelli,
A. Makromol. Chem., Rapid Commun. 1992, 13, 265. (c) Pellecchia,
C.; Proto, A.; Longo, P.; Zambelli, A. Makromol. Chem., Rapid
Commun. 1992, 13, 277. (d) Campbell, R. E. (Dow Chemical Co.) Int.
Pat. Appl. WO 93/03,067 (Chem. Abstr. 1993, 119, 204155b); U.S. Pat.
Appl. 5,066,741, continuation of Eur. Pat. Appl. Ep 421,659 (Chem.
Abstr. 1991, 115, 72440j). (e) Pellecchia, C.; Pappalardo, D.; Oliva,
L.; Zambelli, A. J . Am. Chem. Soc. 1995, 117, 6593.
† University of Massachusetts.
‡ Universidad de Alcala´.
X Abstract published in Advance ACS Abstracts, October 15, 1996.
(1) (a) Ishihara, N.; Seimiya, T.; Kuramoto, M.; Uoi, M. Macromol-
ecules 1986, 19, 2464. (b) Ishihara, N.; Kuramoto, M.; Uoi, M.
Macromolecules 1988, 21, 3356.
(2) (a) Chien, J . C. W.; Salajka, Z. J . Polym. Sci.: Part A, Polym.
Chem. 1991, 29, 1253. (b) Zambelli, A.; Pellecchia, C.; Oliva, L.; Longo,
P.; Grassi, A. Makromol. Chem. 1991, 192, 223. (c) Chien, J . C. W.;
Salajka, Z.; Dong, S. Macromolecules 1992, 25, 3199.
(3) (a) Kucht, A.; Kucht, H.; Barry, S.; Chien, J . C. W.; Rausch, M.
D. Organometallics 1993, 12, 3075. (b) Ready, T. E.; Day, R. O.; Chien,
J . C. W.; Rausch, M. D. Macromolecules 1993, 26, 5822. (c) Kucht,
H.; Kucht, A.; Chien, J . C. W.; Rausch, M. D. Appl. Organomet. Chem.
1994, 8, 393.
(4) (a) J ordan, R. F.; Bajgur, C. S.; Willett, R.; Scott, B. J . Am. Chem.
Soc. 1986, 108, 7410. (b) J ordan, R. F. Adv. Organomet. Chem. 1991,
32, 325.
S0276-7333(96)00475-X CCC: $12.00 © 1996 American Chemical Society

Ti-Cp Complexes
Organometallics, Vol. 15, No. 23, 1996 4945
Sch em e 1
the multihapto coordination of the phenyl ring has been
demonstrated in solution as well as in the solid state.7
Recently, there is interest in the study of substituted
cyclopentadienylmetal complexes containing a terminal
donor group in the side chain.10 Coordination of the
pendant Lewis base to a metal center has been described
for several half-sandwich compounds. Yanlong et al.
have demonstrated chelation of the pendant ligand in
(C5H4CH2CH2OMe)TiCl3 by X-ray studies.11 We have
also recently reported the synthesis of (C5H4CH2CH2-
NMe2)TiCl3 and (C5Me4CH2CH2NMe2)TiCl3 and ob-
tained structural and Ziegler-Natta polymerization
data. Intramolecular coordination of nitrogen to tita-
nium was proposed in these complexes.12 This Lewis
acid-base interaction occurs between the lone pair of
electrons on nitrogen and the doubly degenerate LUMO
2
2
of e symmetry (basically metal-dx -y and -dxy in char-
acter) extended along a plane parallel to the cyclopen-
tadienyl ring in CpTiCl3.13 During the course of the
present work, X-ray diffraction evidence for a Ti-N
interaction was obtained for the related N-pyrrolidinyl
analog [C5H4CH2CH2N(CH2)4]TiCl3.10h
The principal objective of this work was to synthesize
similar compounds where the basic group on the sub-
stituted cyclopentadienyl ligand was a π-electron system
such as in [C5Me4CH2CH2Ph]- (1-) and to investigate
the Ti-Ph interactions. Okuda et al. have shown14
chelation of the vinyl π-electron system to the metal in
the case of the (C5Me4CH2CH2CHdCH2)- ligand.
We describe here the synthesis of new precursors for
the preparation of organometallic compounds C5Me4(H)-
CH2CH2Ph (1) and C5Me4(SiMe3)CH2CH2Ph (2), the
titanium complexes (C5Me4CH2CH2Ph)TiCl3 (3),
(C5Me4CH2CH2Ph)TiMe3 (4), “cationic” [(C5Me4CH2-
CH2Ph)TiMe2]+[B(C6F5)4]- (5), and the hydrolysis prod-
uct of 4 [(C5Me4CH2CH2Ph)TiMe2]2(µ-O) (6), as well as
olefin polymerization catalysis of 3 in comparison with
the reference compound (C5Me5)TiCl3 (7) and 5, obtained
by in situ reaction of 4 with 1 equiv of [Ph3C][B(C6F5)4].
Results of a single-crystal X-ray diffraction study on 3
are also presented and discussed.
Compound 1 was prepared using a procedure similar
to that reported by Okuda for C5Me4(H)CH2CH2CHd
CH215 and was isolated as a golden-yellow liquid in good
yield. Its 1H-NMR spectrum is consistent with a
mixture of several isomers, and follows the pattern
found for C5Me4(H)CH2CH2NMe2.16
The stepwise reaction of 1 with K metal and subse-
quent treatment of the resulting potassium salt with
Me3SiCl in THF afforded the silyl derivative 2 as a light-
sensitive yellow liquid (Scheme 1). Examination of the
1H-NMR spectrum of 2 reveals the fluxional behavior
of the Me3Si group around the C5 core of the ring by
sigmatropic shifting of the ring C-Si bond. The latter
is in agreement with earlier findings for C5Me5(SiMe3)
or C5Me4(SiMe3)CH2CH2NMe2.17 In these spectra, the
C5Me4(SiMe3) fragment is represented by a broad singlet
at high field for protons of the Me3Si group and a broad
singlet for the protons of the methyl groups on the ring.
The other fragment (i.e., -CH2CH2Ph) is observed as
two multiplets for the ethylenic side chain and a
multiplet at low field for the aromatic protons.
Resu lts a n d Discu ssion
Syn th esis. NMR and analytical data for 1-5 are
given in the Experimental Section. Only selected data
will be presented for this discussion.
Addition of 1 equiv of 2 to a solution of TiCl4 in
toluene, followed by workup of the reaction mixture,
gave complex 3 as fairly air-stable red crystals (Scheme
(9) (a) Grassi, A.; Pellecchia, C.; Oliva, L. Macromol. Chem. Phys.
1995, 196, 1093. (b) Grassi, A.; Zambelli, A.; Laschi, F. Organome-
tallics 1996, 15, 480.
1
1). In its H-NMR spectrum in either C6D6 or CDCl3,
(10) (a) Ogasa, M.; Mallin, D. T.; Macomber, D. W.; Rausch, M. D.;
Rogers, R. D.; Rollins, A. N. J . Organomet. Chem. 1991, 405, 41. (b)
Siemeling, U. J . Chem. Soc., Chem. Commun. 1992, 1335. (c) Hughes,
A. K.; Meetsma, A.; Teuben, J . H. Organometallics 1993, 12, 1936. (d)
Wang, T.-F.; Lee, T.-Y.; Chou, J .-W.; Ong, C.-W. J . Organomet. Chem.
1992, 423, 31. (e) Wang, T.-F.; Wen, Y.-S. J . Organomet. Chem. 1992,
439, 155. (f) J utzi, P.; Dahlhaus, J .; Kristen, M. D. J . Organomet.
Chem. 1993, 450, C1. (g) J utzi, P.; Kristen, M. D.; Dahlhaus, J .;
Newmann, B.; Stammler, H.-G. Organometallics 1993, 12, 2980. (h)
Herrmann, W. A.; Morawietz, M. J . A.; Priermeier, T.; Mashima, K.
J . Organomet. Chem. 1995, 486, 291. (h) Okuda, J .; du Plooy, K. E.;
Toscano, P. J . J . Organomet. Chem. 1995, 495, 195.
(11) Qichen, H.; Yanlong, Q.; Guisheng, L.; Youqi, T. Trans. Met.
Chem. 1990, 15, 48.
(12) (a) Flores, J . C.; Chien, J . C. W.; Rausch, M. D. Organometallics
1994, 13, 4140. (b) Flores, J . C.; Chien, J . C. W.; Rausch, M. D.
Macromolecules, in press.
the methyl protons on the five-membered ring appear
as two singlets, and the ethylene bridge as two distinct
triplets, where the one at higher field is assigned to
1
-CH2Ph by H-1H decoupling. The aromatic protons
on the phenyl ring gave a doublet for the ortho protons
at higher field than a multiplet for the para and meta
ones. The 13C-NMR spectrum of 3 in CDCl3 shows all
the expected peaks with chemical shifts and spin-spin
coupling constants in the normal range.
It is well-known that the ortho protons of an η6-arene
(e.g., η6-toluene) coordinated to an electronically unsat-
(13) Nadasdi, T. T.; Huang, Y.; Stephan, D. W. Inorg. Chem. 1993,
32, 347.
(14) Zimmermann, K. H.; Pilato, R. S.; Horva´th, I. T.; Okuda, J .
Organometallics 1992, 11, 3935. (b) Okuda, J .; Zimmermann, K. H.
Chem. Ber. 1992, 125, 637 and references therein.
(15) Okuda, J .; Zimmermann, K. H. J . Organomet. Chem. 1988, 344,
C1.
(16) J utzi, P.; Dahlhaus, J . Synthesis 1993, 7, 684.
(17) (a) J utzi, P. Chem. Rev. 1986, 86, 983. (b) Dahlhaus, J .; Bangel,
M.; J utzi, P. J . Organomet. Chem. 1994, 474, 55.

4946 Organometallics, Vol. 15, No. 23, 1996
Flores et al.
Ta ble 1. 1H a n d 13C NMR Da ta for th e P h en yl
and very soluble in dichloromethane. It is highly air-
sensitive but thermally stable at room temperature as
a solid. However, solutions of 5 in dichloromethane
readily decompose above 0 °C in less than 15 min. For
the C5Me4CH2CH2-fragment, both 1H- and 13C-NMR
spectroscopic data of 5 are very similar to the data found
for 3 and 4. For instance, compared with its precursor
4, the 1H-NMR spectrum of 5 in CD2Cl2 shows the same
splitting pattern for this group, and almost all reso-
nances are shifted to slightly lower field (ca. 0.2
ppm)sshifts expected for a more electron-deficient
metal center in 5. However, the Ti-Me singlet is
shifted 0.4 ppm to higher field. This change can only
be attributed to an anisotropic effect due to the proxim-
ity of the phenyl and the TiMe2 groups in 5. Other
Gr ou p in Com p ou n d s 3-5
1H-NMR (ppm)
δ
assgnt (δ)
3a
7.02
7.20-7.27
4b
5c
∆δd
ortho-Hf
meta-Hg
para-Hg
7.16
7.27
7.19
7.03
8.35
8.51
-0.13
+1.08
+1.32
e
}
13C-NMR (ppm/Hz)
δ/1J CH
3a
4a
5c
145.3
∆δ/∆1J CH
+3.6/-
d
assgnt
ipso-C
140.2
141.7
ortho-C
meta-C
para-C
128.5/159
128.6/157
126.5/158
128.3/159
128.6/156
126.0/159
137.6/175
125.8/168
130.9/175
+9.3/+16
-2.8/+12
+4.9/+16
1
interesting features in the H- and 13C-NMR spectra of
1
5 are the chemical shift and J CH observed for the C6H5
a
b
d
CDCl3, 25 °C. CD2Cl2, 25 °C. c CD2Cl2, -50 °C. ∆δ ) δ(5)
- δ(4); ∆J ) J (5) - J (4). e Multiplet. f Doublet. Triplet.
g
group. Thus, again compared with its precursor 4, the
two triplets for the meta- and para-protons appear
shifted to lower field (∆δ ca. 1.1 and 1.3 ppm, respec-
tively), whereas the doublet for the ortho-protons is
shifted slightly to higher field (see Table 1). Even more
significant are the field shifts (∆δ from ca. -3 up to
+9 ppm) for the C6-ring carbons relative to the compa-
urated group 4 compound are shifted in 1H-NMR to
lower field with respect to the ortho protons on the free
arene.7,18 In contrast, for benzyl complexes the elec-
tronic unsaturation is very often relieved via ηn-benzyl
interactions (n ) 1-3), resulting in a shift of the ortho
protons to higher field.19 The study of the aromatic
region for 3 (see Table 1 and Experimental Section)
leads to the conclusion that coordination of the phenyl
ring to the titanium center is very unlikely in solution.
There is also no coordination in the solid state as shown
by X-ray diffraction studies, since the phenyl ring is
located far away from the metal (vide infra).
1
rable values in 4, together with increasing of the J CH
(∆1J CH ) 12-16 Hz) for the ortho- meta-, and para-
carbons (see Table 1). These differences indicate an
important change in the electronic environment of the
phenyl group in 5 compared to 4. Similar observations
have been made in “cationic” compounds of the type
[CpMR2L]+ (M ) Ti, Zr, Hf; L ) η6-arene), where arene
multihapto coordination to the metal has been demon-
strated in solution,7 as well as in the solid state.7c-e,g
Therefore, we propose an ηn-coordinate phenyl group
(most likely η6) in compound 5. Besides, NMR experi-
ments at different concentrations and temperatures
(never above -10 °C to avoid thermal decomposition)
show the phenyl group in 5 to be intramolecularly
coordinated to Ti and strongly bound as it does not
exchange in dichloromethane. The steric relief rela-
tive to 3 or 4, together with the stronger Lewis acidity
of the Ti(IV)+ center in 5, facilitate the Ti-Ph intra-
molecular coordination in the latter, conferring to
the cation in ansa-titanocenium character (16-electron
complex).
As mentioned before, in compounds like (C5R4CH2-
CH2Y)TiCl3 (Y ) -N(CH2)4,5, R ) H;10h Y ) -OMe, R
) H;11 Y ) -NMe2, R ) H, Me12), the Y function is
intramolecularly coordinated to titanium. The different
result found for 3 could be related to the fact that the
phenyl group is a weaker base compared to the N- and
O-containing ligands and also possibly to steric effects.
A peralkylation reaction of 3 with MeLi in pentane
at low temperature led to a thermally-stable moisture-
sensitive yellow crystalline solid, characterized as the
1
trimethyl compound 4 (Scheme 1). The H-NMR spec-
trum of 4 is fairly similar to the spectrum observed for
3, with the addition of an intense singlet for the methyl
protons attached to titanium. In different deuterated
solvents, the resonance for the CH2CH2 backbone fol-
lows an AA′BB′ splitting pattern, and the low-field
region is better resolved. Thus, from higher to lower
field a doublet, a triplet and another triplet are recorded
for the ortho, para, and meta protons, respectively (see
Table 1 and Experimental Section). As in the case of
Recrystallization in wet pentane of a sample of the
trimethyl compound 4, led to the isolation of the µ-oxo
compound 6 as a thermally-stable, moisture-sensitive
pale-yellow microcrystalline solid (Scheme 1). Com-
plexes such as C5Me5TiMe3 have been found to be very
moisture sensitive,20 and the formation of 6 results from
the hydrolysis of 4. This oxo compound has been
1
compound 3, neither H- nor 13C-NMR data of 4 indicate
1
characterized by elemental analyses and H-NMR. The
any Ti-Ph interaction.
1H-NMR spectrum of 6 in C6D6 shows the Ti-Me
protons at 1.06 ppm with an integral ratio 1:1 compared
to any of the two C5M4 signals. In this case, the
ethylenic side chain is recorded as a complicated mul-
tiplet (δ 2.50-2.73) and the aromatic protons on the
phenyl ring grouped in a singlet multiplet (δ 7.00-7.19).
Str u ctu r e of (C5Me4CH2CH2P h )TiCl3 (3). Single
crystals of 3 were obtained by recrystallization from a
dichloromethane/toluene mixture at -20 °C. Figure 1
gives an ORTEP view of the structure of 3 together with
Addition of [Ph3C]+[B(C6F5)4]- to a hexane suspension
of 4 at -40 °C, followed by slow warming to room
temperature, afforded the “cationic” compound
[(C5Me4CH2CH2Ph)TiMe2]+[B(C6F5)4]- (5) as a mustard-
yellow solid in almost quantitative yield (Scheme 1). The
Ph3CMe byproduct was isolated (97% yield) spectro-
scopically pure from the mother liquor of this reaction.
Compound 5 is insoluble in hexanes or aromatic solvents
(18) (a) Horton, A. D.; Frijns, J . H. G. Angew. Chem., Int. Ed. Engl.
1991, 30, 1152. (b) Solari, E.; Floriani, C.; Chiesi-Villa, A.; Guastini,
C. J . Chem. Soc., Chem. Commun. 1989, 1747. (c) Bochmann, M.;
Karger, G.; J aggar, A. J . J . Chem. Soc., Chem. Commun. 1990, 1038.
(19) For a discussion see: Reference 10c and literature cited therein.
(20) Blanco, S. G.; Go´mez-Sal, P.; Carreras, S. M.; Mena, M.; Royo,
P.; Serrano, R. J . Chem. Soc., Chem. Commun. 1986, 1572.

Ti-Cp Complexes
Organometallics, Vol. 15, No. 23, 1996 4947
the addition to the double bond is cis.21 They propose
that the active species is similar to a (Scheme 2) with
the addition of one η2 coordinated styrene through the
vinylic double bond.9b,21b In this model they also propose
the ηn coordination of the phenyl group of the last
inserted monomer, which accounts for the formation of
a benzyl-type growing chain due to 2,1-insertions. The
lowering in A observed for 3/MAO compared to 7/MAO
could be merely due to the steric hindrance of the
cyclopentadienyl ligand. However, another reasonable
interpretation, derived from Zambelli’s mechanism,9b,21b
could be the formation of intermediate b (Scheme 2),
which leads to a cis-secondary mode for the migratory
insertion. This intermediate bears a multihapto coor-
dination of styrene, by both the vinylic double bond and
the aromatic ring and of the benzyl group of the last
inserted monomer as well.2b This proposed mechanism
is supported by recent X-ray molecular structures
obtained for group 4 monocyclopentadienyl cationic
complexes7d,e as well as the isolation of compound 5 in
this work. The geometric requirement for the multi-
hapto interactions is not met by a group 4 metal with
bis(cyclopentadienyl) ligands, thus they are not suited
for syndiospecific styrene polymerization. That is also
the case for species c (Scheme 3) which has a pseudo-
metallocene character.
F igu r e 1. Structure of (C5Me4CH2CH2Ph)TiCl3 (3), show-
ing the atomic numbering scheme.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 3a
Bond Lengths
Ti-Cl(1)
Ti-Cl(2)
2.221(2)
2.241(2)
Ti-Cl(3)
Ti-Cp
2.245(2)
2.011(3)
Bond Angles
Cl(1)-Ti-Cl(2)
Cl(1)-Ti-Cl(3)
Cl(2)-Ti-Cl(3)
102.7(1)
103.9(1)
102.1(1)
Cl(1)-Ti-Cp
Cl(2)-Ti-Cp
Cl(3)-Ti-Cp
115.8(1)
115.4(1)
115.1(1)
a
Cp is the center of the cyclopentadienyl ring.
Therefore, we tentatively suggest that the active
species derived from 3 is in equilibrium between two
states, one with (c in Scheme 3) and one without (a in
Scheme 3) intramolecular phenyl coordination to Ti.
Species a polymerizes styrene proceeding through mul-
tihapto coordination of the monomer as shown in
Scheme 2, whereas the Ph-Ti interaction in species c
blocks the monomer coordination. As a result, starting
with the same concentration of precursors 3 and 7, the
concentration of active species formed from them is
greater for the latter.
Table 4 summarizes the results for 3/MAO in the
polymerization of ethylene. It has an A value of about
3 × 106 g polymer/(molTi‚[C2H4]‚h), which is much
greater than CpTiCl3/MAO.12 (C5H4CH2CH2NMe2)-
TiCl3/MAO has A for ethylene comparable to 3/MAO,
where for the former intramolecular coordination of the
amino group has also been proposed.12a
the atom labeling, while Table 2 presents selected bond
distance and angle data for the coordination geometry
of the titanium atom. The metal center and phenyl
group are located at opposite faces of the cyclopentadi-
enyl ring. The geometry around Ti, as defined by the
centroid of the five-membered ring and the Cl atoms, is
roughly tetrahedral, the angles from the centroid to the
Cl atoms being much larger (average 115.4(1)°) than the
angles between the Cl atoms (average 102.9(1)°). The
Ti-Cl(1) bond distance is slightly shorter (ca. 0.02 Å)
than the other Ti-Cl separations, and there is a small
spread in the Ti-C(ring) distances. The substitution
of the benzyl group at C(6) causes no apparent distortion
of the C5Me4(CH2-) group, which has local 5-fold
symmetry to within the standard deviations. The
average C-C distance in the ring is 1.413(7) Å, while
the average exocyclic distance to carbons C(6) to C(10)
is 1.501(7) Å.
Table 5 summarizes the results obtained by 5, pre-
pared in situ by reacting 4 with 1 equiv of [Ph3C]-
[B(C6F5)4], in the polymerization of ethylene and sty-
rene. It is noteworthy that this catalytic system was
inactive for either monomer in the absence of triisobu-
tylaluminum (TIBA) (runs 10, 12, and 15). However,
the presence of a sufficient amount of TIBA (1 mM for
ethylene, run 11; 5 mM for styrene, runs 14 and 17) to
scavenge any monomer or solvent impurities led to the
formation of the corresponding polymers. The increase
of A(ethylene) compared to 3/MAO (run 11, Table 5 vs
run 9, Table 4) could be understood as a result of a
looser ion-pair interaction of the active species (e.g., c
in Scheme 3) with [B(C6F5)4]- compared to MAO, which
might even shift the equilibrium depicted in Scheme 3
to the metallocene-like c-species. However, A(styrene)
compared to 3/MAO (runs 14 and 17, Table 5 vs runs 4
and 5, Table 3) is comparable or slightly lower, and both
catalyst systems produce the same % s-PS. For 7/MAO
P olym er iza tion Ca ta lysis. The C5Me5TiCl3 (7)/
MAO catalyst system has previously been found to be
highly active and syndiospecific for the polymerization
of styrene.1b,3c Table 3 summarizes the results obtained
with both 3/MAO and 7/MAO under several polymeri-
zation conditions. The data show differences in activity
(A) as well as syndioselectivity and the effect of Tp on
them.
The maximum polymerization activities for 7/MAO
and 3/MAO were found at Tp ) 70 °C. Both the A value
and yield of s-PS are lower at 90 °C, which could be due
to decomposition of the titanium complexes. The po-
lymerization activities at 25 °C are only one-tenth of
those at 50 °C for both catalyst systems. The A values
over the entire temperature range were about 2-3 times
smaller for 3/MAO than 7/MAO, whereas they produce
the same % s-PS (see Table 3).
Zambelli et al. have established that the mechanism
of syndiospecific styrene polymerization in the presence
of half-sandwich titanium catalysts is a polyinsertion
of the monomer, the regiospecificity is secondary, and
(21) (a) Reference 2b. (b) Longo, P.; Proto, A.; Zambelli, A. Macro-
mol. Chem. Phys. 1995, 196, 3015 and references therein.

4948 Organometallics, Vol. 15, No. 23, 1996
Ta ble 3. Styr en e P olym er iza tion Ca ta lyzed by 3 or 7/MAOa
(C5Me5)TiCl3 (7) [C5Me4(CH2CH2Ph)]TiCl3 (3)
Flores et al.
run no.
[Ti] (µM)
Al/Ti
Tp (°C)
yield (g)
Ab × 10-6
% s-PSc
Tm (°C)
yield (g)
Ab × 10-6
% s-PSc
Tm (°C)
1
2
3
4
25
50
50
50
2000
2000
4000
4000
25
25
25
50
0.016
0.028
0.044
0.441
0.29
0.26
0.40
4.06
56
68
86
90
0.058
0.698
1.07
12.8
88
89
271.1
273.2
269.1
271.4
260.3
268.3
258.8
263.4
5
50
50
4000
4000
70
90
0.932
0.701
17.1
12.9
95
92
0.899
0.580
8.27
5.33
95
80
6
a
b
Polymerization conditions: volume, 50 mL toluene + 5 mL styrene; tp ) 0.5 h for 7 and 1 h for 3. g of bulk polymer/(molTi × molstyrene
× h). c % s-PS ) (g of 2-butanone insoluble polymer/g of bulk polymer) × 100.
chemicals from Aldrich, unless otherwise stated. [Ph3C]+
Sch em e 2
[B(C6F5)4]- was prepared according to a literature procedure.5a
NMR spectra were recorded on Varian Unity 500+ (1H-NMR,
500 MHz; 13C-NMR, 125 MHz) and Varian XL 200 NMR
spectrometers. Chemical shifts (δ) are reported in ppm
referenced to TMS. Elemental analyses were performed by
the University of Massachusetts or University of Alcala´
Microanalytical Laboratories. Styrene was purified by distil-
lation from calcium hydride under reduced pressure and stored
at -25 °C under argon in darkness. Polymerization grade
ethylene was dried and purified by passing it through a
Matheson Gas Purifier (Model 6436). Methylaluminoxane
(MAO) was purchased from Akzo. The procedures used to
polymerize styrene3 and ethylene5b,23 have been previously
given in detail. A Perkin-Elmer DSC-4 Thermoanalytic in-
strument was used to obtain DSC melting endotherms.
Polyethylene molecular weight determinations were made by
viscosity measurements in decalin at 135 °C.
1-(2-P h e n yle t h yl)-2,3,4,5-t e t r a m e t h ylcyclop e n t a d i-
Sch em e 3
en e (1). (2-Bromoethyl)benzene (11.10 g, 60 mmol) was added
dropwise to an excess of magnesium turnings (1.70 g, 70 mmol)
in diethyl ether (50 mL) at room temperature. The reaction
mixture was subsequently heated at reflux for 1 h. After
cooling, the Grignard reagent was reacted in situ by the slow
addition of cis, trans-2,3,4,5-tetramethyl-2-cyclopentenone
(8.30 g, 60 mmol) at room temperature. The reaction mixture
was then heated at reflux for 2 h, quenched by addition of 150
g of ice, treated with concentrated HCl (40 mL), and stirred
for 2 h. The organic layer was collected and the aqueous layer
extracted with diethyl ether (4 × 50 mL). The combined
Ta ble 4. Eth ylen e P olym er iza tion Ca ta lyzed by
3/MAOa
run no. Al/Ti Tp (°C) yield(g) Ab × 10-6 Tm (°C) Mw × 10-4
organic extracts were washed with a 10% aqueous solution of
NaHCO3 (4 × 60 mL) and a saturated aqueous solution of NaCl
(2 × 50 mL), before being dried over MgSO4. After filtration,
the volatiles were removed under vacuum to give a brownish
liquid, which was distilled (111-112 °C at 10-3 mmHg) to
afford pure 1 as a yellow-golden liquid. Yield: 8.78 g (65%).
Anal. Calcd for C17H22: C, 90.20; H, 9.80. Found: C, 90.38;
H, 9.81. 1H-NMR (CDCl3): δ 0.99 (d, J ) 8.4 Hz, C5Me4H),
1.04 (d, J ) 8.6 Hz, C5Me4H), 1.63, 1.72, 1.77 and 1.83 (major)
(4 s, ring-Me on sp2 carbons)[12H]; 2.04 (m, 1H, C5Me4H);
2.48 (m, 2H, CH2Ph); 2.61-2.68 (m, 2H, CH2); 7.14-7.27 (m,
5H, Ph).
7
8
9
2000
4000
4000
20
20
50
0.164
0.290
0.147
2.12
3.75
2.56
136.8
137.3
136.5
5.3
3.4
1.4
a
Polymerization conditions: volume, 50 mL toluene; [Ti] ) 50
µM; tp ) 5 min; PC H ) 15 psig, [C2H4](20 °C) ) 0.37 M, [C2H4](50 °C)
) 0.28 M. g of polymer/(molTi × [C2H4] × h).
2
4
b
compared to the Cp*TiMe3/[Ph3C][B(C6F5)4] catalytic
system, a higher A(styrene) and the same syndiospeci-
ficity has been previously observed.3c The discrepancy
in the trend of A for the current case could be explained
if the positive effect of a weaker counterion association
is compensated by the above mentioned shift of the
equilibrium in Scheme 3 to the c species, which we
suggest not to be active vs styrene.
[1-(2-P h en yleth yl)-2,3,4,5-tetr am eth ylcyclopen tadien yl]-
tr im eth ylsila n e (2). A reaction of C5Me4(H)CH2CH2Ph (1)
(3.15 g, 13.9 mmol) with potassium metal (0.42 g, 13.9 mmol)
was carried out in refluxing THF (50 mL) over night. Removal
of the solvent under reduced pressure afforded a white
potassium salt which was washed with pentane (50 mL), dried,
redissolved in THF (50 mL), and reacted with Me3SiCl (1.51
g, 13.9 mmol) at 0 °C. After stirring for 5 h the THF was
evaporated and the residue was extracted with pentane (2 ×
40 mL). The silyl derivative 2 was isolated as an analytically
pure yellow-golden liquid by simple removal of the solvent from
Exp er im en ta l Section
All operations were performed under an argon atmosphere
using Schlenk or drybox techniques. Argon was deoxygenated
with activated BTS catalyst and dried with molecular sieves
and P2O5. Solvents were purified as described elsewhere.22
(2-Bromoethyl)benzene were purchased from Fluka and other
(22) Perrin, D. P.; Armarego, W. L. F. Purification of Laboratory
Chemicals, 3rd ed.; Pergamon Press Ltd.: Oxford, U.K., 1988.
(23) 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.

Ti-Cp Complexes
Organometallics, Vol. 15, No. 23, 1996 4949
Ta ble 5. Eth ylen e or Styr en e P olym er iza tion Ca ta lyzed by 4/Coca ta lysta
run no.
monomerb
Tp (°C)
tp (min)
cocatalyst
Al/Ti
yield (g)
Ac × 10-6
% s-PSd
10
11
12
13
14
15
16
17
ethylene
ethylene
styrene
styrene
styrene
styrene
styrene
styrene
50
50
50
50
50
70
70
70
60
1e
[Ph3C]+[B(C6F5)4]-
0
20
0
20
100
0
0
[Ph3C]+[B(C6F5)4]-/TIBA
[Ph3C]+[B(C6F5)4]-
0.331
0
0
0.435
0
0
28.8
60
60
60
60
60
60
[Ph3C]+[B(C6F5)4]-/TIBA
[Ph3C]+[B(C6F5)4]-/TIBA
[Ph3C]+[B(C6F5)4]-
4.00
92
96
[Ph3C]+[B(C6F5)4]-/TIBA
[Ph3C]+[B(C6F5)4]-/TIBA
20
100
0.543
4.99
a
b
Polymerization conditions: volume, 50 mL toluene; [Ti] ) 50 µM; ratio [Ph3C][B(C6F5)4]/Ti ) 1. For runs 10 and 11, PC H ) 15 psig,
2
4
d
[C2H4](50
) 0.28 M. For runs 12-17, 5 mL of styrene. c A vs ethylene; see note b of Table 4; A vs styrene; see note b of Table 3. See
°C)
note c of Table 3. e The polymer produced stops the stirring of the polymerization mixtures in less than 1 min.
Ta ble 6. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
for 3
the combined extracts. Yield: 3.40 g (82%). Anal. Calcd for
20H30Si: C, 80.46; H, 10.13. Found: C, 80.46; H, 10.30. 1H-
C
Diffractometer
empirical formula
fw
Enraf-Nonius CAD-4
C17H21Cl3Ti
379.61
NMR (CDCl3, 25 °C): δ -0.15 (s, 9H, SiMe3); 1.81 (br s, 8 Hz,
12H, C5Me4); 2.05 (m, 2H, CH2Ph); 2.50 (m, 2H, CH2); 7.21
(br s, 8 Hz, Ph).
temp
293(2) K
[1-(2-P h en yleth yl)-2,3,4,5-tetr am eth ylcyclopen tadien yl]-
tr ich lor otita n iu m (3). A solution of 2 (3.38 g, 11.3 mmol)
in toluene (20 mL) was slowly added to a second solution of
TiCl4 (2.14 g, 11.3 mmol) in toluene (80 mL) at -78 °C. After
the addition was completed the mixture was allowed to warm
to room temperature and stirred overnight. A small amount
of sticky red precipitate was filtered from the bright red
solution. Evaporation of the solvent afforded crude 3, which
was washed with pentane (2 × 40 mL), recrystallized from
CH2Cl2/toluene, and collected in two crops as air-stable red
needles. Yield: 2.52 g (59%). Anal. Calcd for C17H21Cl3Ti:
C, 53.79; H, 5.58. Found: C, 54.23; H, 5.39. 1H-NMR (CDCl3,
25 °C): δ 2.18 (s, 6H, C5Me4); 2.36 (s, 6H, C5Me4); 2.73 (t, 2H,
J ) 7.5 Hz, CH2Ph); 3.16 (t, 2H, J ) 7.5 Hz, CH2); 7.02 (d, 2H,
o-Ph); 7.20-7.27 (m, 3H, m- and p-Ph). 1H-NMR (C6D6, 25
°C): δ 1.81 (s, 6H, C5Me4); 1.90 (s, 6H, C5Me4); 2.31 (t, 2H, J
) 7.5 Hz, CH2Ph); 2.92 (t, 2H, J ) 7.5 Hz, CH2); 6.71 (d, 2H,
o-Ph); 6.97-7.05 (m, 3H, m- and p-Ph). 13C-NMR (CDCl3, 25
wavelength
0.710 73 Å; monochromated
Mo KR
cryst system
space group
a (Å)
b (Å)
c (Å)
monoclinic
P21/a
15.114(2)
7.212(4)
17.131(4)
102.45(2)
1823.4(11)
4
1.383
9.00
empirical; ψ scans
784
0.3 × 0.55 × 0.2
5-44; ω/2θ scans
0 e h e 15, 0 e k e 7,
-17 e l e 17
2073
2073 [Rint ) 0.0000]
full-matrix least-squares
on F2
â(deg)
V (Å3)
Z
Dcalcd (g cm-1
)
abs coeff (cm-1
abs corr
)
F(000)
cryst size (mm)
2θ range (deg)
index ranges
reflcns collcd
indepdt reflcns
refinement method
1
1
°C): δ 14.13 (C5Me4, J CH ) 128.8 Hz); 14.31 (C5Me4, J CH
)
1
1
129.0 Hz); 31.38 (CH2, J CH ) 130.9 Hz); 35.90 (CH2Ph, J CH
) 128.4 Hz); 126.47 (p-Ph, 1J CH ) 158.0 Hz); 128.51 (o-Ph, 1J CH
) 159.0 Hz); 128.59 (m-Ph, 1J CH ) 157.3 Hz); 137.78 (ipso-C5-
Me4); 138.00 and 140.10 (C5Me4); 140.22 (ipso-Ph).
data/restraints/params
goodness of fit on F2
final R indices
2073/0/194
1.105
R1 ) 0.0387, wR2 ) 0.0895
on 1409 data
R1 ) 0.0809, wR2 ) 0.1123
0.227 and -0.254
[I > 2σ(I)]
[1-(2-P h en yleth yl)-2,3,4,5-tetr am eth ylcyclopen tadien yl]-
tr im eth yltita n iu m (4). A solution of MeLi‚LiBr (6.0 mL, 1.7
M in diethyl ether) was slowly added to a suspension of
compound 3 (1.10 g, 2.9 mmol) in pentane (50 mL) at -40 °C.
When the addition was completed the mixture was gradually
(1 h) warmed to room temperature, and the resulting yellow
solution filtered from a white precipitate. Vacuum distillation
of the solvent gave a yellow microcrystalline solid which was
recrystallized in pentane, producing a yellow crystalline solid
characterized as the trimethyl compound 4. Yield: 0.81 g
(88%). Anal. Calcd for C20H30Ti: C, 75.46; H, 9.50. Found:
C, 75.08; H, 9.42. 1H-NMR (CDCl3, 25 °C): δ 0.71 (s, 9H, Ti-
Me); 1.86 (s, 6H, C5Me4); 1.94 (s, 6H, C5Me4); 2.56-2.60 (m,
2HAA′, CH2Ph); 2.74-2.78 (m, 2HBB′, CH2); 7.16 (d, 2H, o-Ph);
7.19 (t, 1H, p-Ph); 7.27 (t, 2H, m-Ph). 1H-NMR (C6D6, 25 °C):
δ 1.01 (s, 9H, Ti-Me); 1.66 (s, 6H, C5Me4); 1.74 (s, 6H, C5Me4);
2.48-2.52 (m, 2HAA′, CH2Ph); 2.60-2.64 (m, 2HBB′, CH2); 6.99
(d, 2H, o-Ph); 7.07 (t, 1H, p-Ph); 7.13 (t, 2H, m-Ph). 1H-NMR
(CD2Cl2, 25 °C): δ 0.71 (s, 9H, Ti-Me); 1.86 (s, 6H, C5Me4);
1.95 (s, 6H, C5Me4); 2.57-2.61 (m, 2HAA′, CH2Ph); 2.74-2.78
R indices (all data)
largest diff peak
and hole (e‚Å-3
)
(0.32 g, 1.0 mmol) and [Ph3C][B(C6F5)4] (0.92 g, 1.0 mmol) as
solids, hexane (20 mL) was added at -40 °C. The resulting
suspension was warmed to room temperature and stirred for
1 h. The solvent was then decanted, and the solid washed
with toluene (2 × 10 mL) and pentane (2 × 10 mL). The Ph3-
CMe byproduct was obtained spectroscopically pure from the
combined mother-liquor and extracts (0.25 g, 97% yield). The
product of this reaction was isolated as a very air-sensitive
mustard-yellow powder, and characterized as compound 5.
This salt was found to be soluble in chlorinated solvents, and
thermally unstable in solution. Yield: 0.93 g (95%). Anal.
Calcd for C43H27BF20Ti: C, 52.58; H, 2.77. Found: C, 53.08;
H, 3.29. 1H-NMR (CD2Cl2, -50 °C): δ 0.27 (s, 6H, Ti-Me);
1.85 (s, 6H, C5Me4); 2.13 (s, 6H, C5Me4); 2.80 (t, 2HAA′, CH2-
Ph); 3.03 (t, 2HBB′, CH2); 7.03 (d, 2H, o-Ph); 8.35 (t, 1H, p-Ph);
8.51 (t, 2H, m-Ph). 13C-NMR (CD2Cl2, -50 °C): δ 12.25 (C5Me4,
1J CH ) 127.2 Hz); 12.39 (C5Me4, 1J CH ) 127.4 Hz); 24.50 (CH2,
1J CH ) 130.1 Hz); 33.99 (CH2Ph, 1J CH ) 131.8 Hz); 64.05 (Ti-
Me; 1J CH ) 125.0 Hz); 125.84 (m-Ph, 1J CH ) 168.1 Hz); 127.06
(m, 2HBB′, CH2); 7.16 (d, 2H, o-Ph); 7.19 (t, 1H, p-Ph); 7.27 (t,
1
2H, m-Ph). 13C-NMR (CDCl3, 25 °C): δ 11.81 (C5Me4, J CH
)
)
126.0 Hz); 12.01 (C5Me4, 1J CH ) 126.0 Hz); 29.66 (CH2, 1J CH
126.6 Hz); 36.93 (CH2Ph, 1J CH ) 127.0 Hz); 60.90 (Ti-Me; 1J CH
) 118.7 Hz); 122.25 (C5Me4); 124.98 (ipso-C5Me4); 125.96 (p-
1
(C5Me4); 127.52 (ipso-C5Me4); 130.87 (p-Ph, J CH ) 175.3 Hz);
1
131.90 (C5Me4); 137.63 (o-Ph, J CH ) 174.5 Hz); 145.27 (ipso-
1
1
Ph). 13C-NMR data for C6F5 of [B(C6F5)4]-: 122-123 (br m,
Ph, J CH ) 159.5 Hz); 128.32 (o-Ph, J CH ) 159.4 Hz); 128.57
1
ipso-C), 135.3 (br, d, 1J CF ) 229.7 Hz, o-C), 137.1 (br d, 1J CF
)
(m-Ph, J CH ) 155.5 Hz); 141.76 (ipso-Ph).
a n sa -{η5:ηn :[1-(2-P h en ylet h yl)-2,3,4,5-t et r a m et h ylcy-
clop en t a d ien yl]d im et h ylt it a n iu m (IV)} Tet r a k is(p en -
t a flu or op h en yl)bor a t e (5). To a mixture of compound 4
235.5 Hz, m-C), 147.0 (br d, J CF ) 243.5 Hz, p-C).
Isola tion of {[1-(2-P h en yleth yl)-2,3,4,5-tetr a m eth ylcy-
clop en ta d ien yl]d im eth yltita n iu m }(µ-oxo) (6). A sample
1

4950 Organometallics, Vol. 15, No. 23, 1996
Flores et al.
of compound 4 (0.70 g, 1.8 mmol) was dissolved in wet pentane.
Concentration of the resulting yellow solution to ca. 10 mL
and cooling at -78 °C overnight gave a yellow solid which was
recrystallized in dry pentane, producing a pale yellow micro-
crystalline solid characterized as the µ-oxo compound 6.
Yield: 0.28 g (49%). Anal. Calcd for C38H54OTi2: C, 73.30;
H, 8.74. Found: C, 72.83; H, 9.01. 1H-NMR (C6D6, 25 °C): δ
1.06 (s, 12H, Ti-Me); 1.71 (s, 12H, C5Me4); 1.79 (s, 12H, C5Me4);
2.50-2.73 (m, 8H, CH2CH2); 7.00-7.19 (m, 10H, Ph).
X-r a y Str u ctu r e Deter m in a tion . The details of the X-ray
data collection, lattice parameters, and physical properties of
the crystal of 3 are summarized in Table 6. Lattice parameters
were determined for a crystal mounted in a Lindemann glass
capillary from 25 reflections in the range 18° > 2θ > 26°. The
reflection data were corrected for Lorentz and polarization
factors and an empirical absorption correction based on ψ
scans. Five standard reflections monitored during the data
collection showed no significant change in intensity. The
structure was solved by direct methods and refined by full-
matrix least-squares methods on F2 using all 2073 independent
reflections in the SHELX-TL set of programs.24 The final
residuals (based on F) for the 1409 reflections with I g 2σ(I)
are R ) 0.039 and Rw ) 0.089. Hydrogen atoms based on
riding model were included. Neutral atom scattering factors
for non-hydrogen atoms were taken from ref 25, while that
tabulated by Stewart et al. was used for hydrogen.26 Correc-
tions for anomalous dispersion were included.27
Ack n ow led gm en t. We are indebted to Dr. M. Gala-
khov (Univ. of Alcala´) for valuable NMR assistance and
discussions and to Dr. A. Chandrasekaran for assistance
with the X-ray structure determination. J .C.F. was
supported by a Ministerio de Educacio´n y Ciencia
(Spain) postdoctoral fellowship.
Su p p or tin g In for m a tion Ava ila ble: Tables S1-S4, list-
ing complete crystallographic information for (C5Me4CH2CH2-
Ph)TiCl3, including atomic coordinates, anisotropic thermal
parameters, H coordinates, and complete bond distances and
angles (4 pages). Ordering information is given on any current
masthead page.
OM960475S
(25) International Tables for X-ray Crystallography; Kynoch Press:
Birmingham, U.K., 1974; Vol. IV, pp 99, 149.
(26) Stewart, R. F.; Davidson, R. F.; Simpson, W. J . J . Chem. Phys.
1965, 42, 3175.
(27) Cromer, D. T.; Liberman, D. J . J . Chem. Phys. 1970, 53, 1891.
(24) Sheldrick, G. M. SHELX-TL; Structure determination and full
matrix least squares refinements program package, 1988.