Synthesis of mono- and dinuclear cyclopentadienyl-aryloxy titanium(IV) complexes

Article abstract of DOI:10.1016/S0022-328X(99)00555-0

This paper reports the reactivity of monocyclopentadienyl titanium complexes [Ti(C₅R₅)Cl₃] (R=H or Me) with phenol and hydroquinones to afford mono- and dinuclear aryloxy derivatives, respectively. The reaction of hydroqui

Full text of DOI:10.1016/S0022-328X(99)00555-0

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 592 (1999) 265–270
Synthesis of mono- and dinuclear cyclopentadienyl–aryloxy
titanium(IV) complexes
S. Are´valo, J.M. Benito, E. de Jesu´s, F.J. de la Mata, J.C. Flores, R. Go´mez *
Departamento de Qu´ımica Inorga´nica, Uni6ersidad de Alcala´, Campus Uni6ersitario, Edificio de Farmacia, E-28871 Alcala´ de Henares, Spain
Received 2 August 1999; accepted 27 September 1999
Abstract
This paper reports the reactivity of monocyclopentadienyl titanium complexes [Ti(C5R5)Cl3] (R=H or Me) with phenol and
hydroquinones to afford mono- and dinuclear aryloxy derivatives, respectively. The reaction of hydroquinones HO(C6H2XY)OH
(X=Y=H, Me; X=H, Y=Me) with [Ti(C5H5)Cl3] gave red–orange microcrystalline solids of the corresponding dinuclear
complexes [{Ti(C5H5)Cl2}2{m-O(C6H2XY)O}] (X=Y=H (1); X=H, Y=Me (2); X=Y=Me (3)) in high yields. However, their
dilithium salts Li2[O(C6H2XY)O] must be used in the treatment with [Ti(C5Me5)Cl3] to produce the expected dinuclear derivatives
[{Ti(C5Me5)Cl2}2{m-O(C6H2XY)O}] (X=Y=H (4); X=H, Y=Me (5); X=Y=Me (6)) as red–orange microcrystals in high
yields too. Reaction of [Ti(C5R5)Cl3] with 4-allyl-2-methoxyphenol (commonly called eugenol) [C6H3(OH)(OMe)(C3H5)] or its
lithium salt led to the monoaryloxy complexes [Ti(C5R5)Cl2{OC6H3(OMe)(C3H5)}] (R=H (7), Me (8)). © 1999 Elsevier Science
S.A. All rights reserved.
Keywords: Titanium; Aryloxy derivatives; Cyclopentadienyl complexes
compared with hybrid half-metallocene analogues [4].
And second because substituted aryloxy ligands could
be suitable groups to attach the metal complex to a
dendrimeric base, i.e. phenyl ether [5] or carbosilane [6]
dendrimers.
In this paper, we wish to present the synthesis and
characterisation of new mono- and dinuclear cyclopen-
tadienyl titanium derivatives containing aryloxy ancil-
lary ligands in their coordination environment, as
models and starting point for the synthesis of periph-
eral metal–dendrimers.
1. Introduction
An area of current interest is the synthesis of metallo-
dendrimers in which the metal has been attached to the
surface for generating new inorganic/organic hybrid
macromolecules with interesting advantages over both
homogeneous and heterogeneous catalysis [1]. On the
other hand, cyclopentadienyl Group 4 metal derivatives
are a family of well-defined homogeneous olefin poly-
merisation catalysts [2], which are very attractive for
their attachment over a dendritic surface, as model
systems for heterogenisation of such complexes on, i.e.
silica supports. As a part of our current research, we
are interested in the synthesis of monocyclopentadi-
enyl–aryloxy derivatives of titanium attached to a den-
drimeric base for two reasons. First, there are several
examples for the synthesis of molecular Cp–aryloxy
complexes of titanium and their use as olefin polymeri-
sation catalysts [3], showing that these complexes are
relatively easy to synthesise and as catalysts could be
2. Results and discussion
2.1. Synthesis of dinuclear complexes
Reactions of [Ti(C5R5)Cl3] (R=H or Me) with hy-
droquinones or their dilithium salts have been studied.
The reaction of HO(C6H2XY)OH (X=Y=H, Me;
X=H, Y=Me) with two equivalents of [Ti(C5H5)Cl3]
in diethyl ether at room temperature (r.t.) gave red
orange microcrystalline solids of dinuclear complexes
[{Ti(C5H5)Cl2}2{m-O(C6H2XY)O}] (X=Y=H (1);
* Corresponding author. Tel.: +34-91-8854685; fax: +34-91-
8854683.
E-mail address: rgomez@inorg.alcala.es (R. Go´mez)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00555-0

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S. Are´6alo et al. / Journal of Organometallic Chemistry 592 (1999) 265–270
The IR spectra of the new aryloxy complexes contain
bands due to the w(CꢀO) at ca. 1215 cm−1 and the
w(TiꢀO) at ca. 900 cm−1, which are in the range
reported for related derivatives [3c,11,12]. 1H-NMR
spectra show a singlet for the protons of the two C5H5
ligands in complexes 1 and 3 and for the methyl groups
of the two C5Me5 rings in compounds 4 and 6. Never-
theless, 2 and 5 exhibit two singlets attributed to the
non-equivalent ‘Ti(C5H5)Cl2’ or ‘Ti(C5Me5)Cl2’ units
bonded to the aryloxy bridging ligands. A relevant
feature is that C5H5 or C5Me5 signals are almost un-
modified on going from the non-substituted to the
disubstituted aryloxy compounds (l 6.78–6.75 for 1–3
or l 2.20–2.18 for 4–6 in CDCl3), indicating that alkyl
substitution on the phenyl ring does not induce signifi-
cant changes in the electronic density of the metal
centre. For the protons of the aryloxy ligands, a singlet
due to the four equivalent hydrogen atoms for com-
plexes 1 and 4 (l 6.92 and l 6.85, respectively) and
another singlet attributed to the two equivalent protons
for complexes 3 and 6 (l 6.81 and l 6.72, respectively)
are observed. These resonance patterns are comparable
to those shown by the analogous derivatives
[{MoTp(NO)X}2{m-O(C6H4)O}] [13] or [{MoTp(O)-
Cl}2{m-N(C6H4)N}] [14], and are expected for homod-
inuclear bonding to the corresponding diphenoxide lig-
ands. However, for compounds 2 and 5 a complex spin
system is observed as a consequence of asymmetric
substitution on the diphenoxide [O(C6H3Me)O]2− unit.
The most interesting feature in their 13C{1H}-NMR
spectra is the almost identical chemical shift of the ipso
carbons bonded directly to the oxygen atoms that are
recorded at the narrow range of l 164.6–164.1 for 2–3
and l 160.8–159.3 for 4–6. For pentamethylcyclopen-
tadienyl complexes, these signals appear at higher field
than those observed for compounds 2 and 3, as the
result of the presence of a more electron-donating
ligand [15].
X=H, Y=Me (2); X=Y=Me (3)) (Scheme 1) in
high yields. Complexes 1–3 are insoluble in hydrocar-
bon solvents and in diethyl ether, but scarcely soluble
in THF and chlorinated solvents. Solubility is slightly
increased on going from the unsubstituted derivative 1
to the dimethyl substituted aryloxy complex 3. Com-
pounds 1–3 are thermally stable but moisture sensitive,
decomposing slowly to the well known oxo complex
[{Ti(C5H5)Cl2}2(m-O)] [7] in the presence of traces of
water.
For compound [Ti(C5Me5)Cl3] no reaction was ob-
served with the hydroquinones in analogous conditions,
whereas at 100°C they gave, in all cases, mixtures of the
predicted complexes with unreacted starting materials.
Moreover, treatment above this temperature led to
decomposition of the organotitanium compounds. A
more suitable procedure consists in the treatment of
[Ti(C5Me5)Cl3] with the dilithium salt of the hy-
droquinones Li2[O(C6H2XY)O] (X=Y=H, Me; X=
H, Y=Me) [8] in a molar ratio 2:1 in dichloromethane
at r.t., affording the expected dinuclear derivatives
[{Ti(C5Me5)Cl2}2{m-O(C6H2XY)O}] (X=Y=H (4);
X=H, Y=Me (5); X=Y=Me (6)) (Scheme 1) as
red–orange microcrystals in high yields. C5Me5 deriva-
tives 4–6 present higher thermal stabilities and solubili-
ties in the common solvents than complexes 1–3
containing the unsubstituted cyclopentadienyl ring.
However, they are likewise moisture sensitive and un-
dergo hydrolysis. For instance, complex 4 produced the
mononuclear compound [Ti(C5Me5)Cl2{O(C6H4)OH}]
by selective hydrolysis of the TiꢀO bond (1H-NMR
evidence) [9]. Subsequent hydrolysis of this intermediate
led to the well known oxo complex [{Ti(C5Me5)Cl2}2(m-
O)] [10].
The IR and NMR data and analytical composition
for complexes 1–6 (see Section 4) are consistent with
the structures depicted in Scheme 1.
Scheme 1.

S. Are´6alo et al. / Journal of Organometallic Chemistry 592 (1999) 265–270
267
Scheme 2.
Reactions of homodinuclear complexes with different
alkylating reagents have been studied. Attempts to pre-
pare tetraalkyl derivatives by treatment of complexes 1
or 6 with LiMe, MeMgCl or AlMe3 were unsuccessful.
In contrast, these processes seem to be appropriated for
more sterically encumbered aryloxy systems [16]. It is
interesting to note that the reaction of complex 1 or 6
with two equivalents of AlMe3 in toluene at r.t. gave a
mixture of previously reported monometallic deriva-
tives [Ti(C5R5)MeCl2] (R=H, Me) [17,18] and
[Ti(C5R5)Me3] (R=H, Me) [19,20] as unique organoti-
tanium species. These results are probably due to the
lack of steric hindrance around the TiꢀO bond
[3a,3b,16] and to the high affinity of aluminium alkyls
for oxo functionalities [21].
thermally stable but moisture sensitive, slightly soluble
in alkanes and very soluble in the rest of the common
solvents.
The structures proposed for the new complexes 7 and
8 are shown in Scheme 2 and their spectroscopic and
analytical data collected in Section 4.
Once more, the IR spectra of the new monoaryloxy
complexes contain bands due to the w(CꢀO) at ca. 1270
cm−1 and the w(TiꢀO) at ca. 890 cm−1, similar to those
found in the dinuclear systems prepared above and
1
other related derivatives [3c,11,12]. The H-NMR spec-
tra of complexes 7 and 8 show the singlet attributed to
the cyclopentadienyl and pentamethylcyclopentadienyl
ligands, and one resonance for the corresponding car-
bon atoms of the rings are observed in their 13C-NMR
spectra. Regarding to the eugenolate moiety, the pres-
ence of three different substituents makes all the phenyl
proton and carbon atoms chemically non-equivalent.
Thus, a set of complex signals for the phenyl ring
protons in the 1H-NMR and six resonances for the
corresponding carbon atoms in the 13C-NMR are de-
tected. The ipso carbon bonded to the TiꢀO unit ap-
pears at l 157.4 for compound 7 and slightly shifted to
higher field for complex 8 (l 153.6), again due to the
different electrodonating properties of the C5H5 and
C5Me5 rings, and both shifted downfield from the reso-
nance of the free eugenol (l 143.7). The chemical shift
of the ipso-C atom bonded to the OMe group is located
at l 150.0 for both complexes, moved 3 ppm downfield
from the free alcohol. This observation is in agreement
with the lack of interaction with the metal centre [22].
2.2. Synthesis of mononuclear complexes
Treatment of [Ti(C5H5)Cl3] with one equivalent of
4-allyl-2-methoxyphenol (commonly called eugenol)
[C6H3(OH)(OMe)(C3H5)] in toluene at 80°C afforded
the aryloxy complex [Ti(C5H5)Cl2{OC6H3(OMe)-
(C3H5)}] (7) (Scheme 2) as red microcrystals in 80%
yield. However, the reaction with [Ti(C5Me5)Cl3] in
analogous conditions was not completed, recovering
1
always large amounts of starting materials. A H-NMR
experiment carried out in a sealed tube shown that a
mixture of [Ti(C5Me5)Cl3] and eugenol in CDCl3 at
100°C for 12 h, yielded almost quantitatively the com-
plex [Ti(C5Me5)Cl2{OC6H3(OMe)(C3H5)}] (8) when the
spectrum was registered keeping such temperature. In
contrast, upon cooling the tube at r.t., the reverse
reaction took place, leading quantitatively to the start-
ing substrates. In a NMR tube scale, compound 8 can
be isolated by means of heating and subsequent re-
moval of the concomitant HCl under vacuum. Unfortu-
nately, this procedure is not appropriated for 8 in a
large scale synthesis. A more convenient method con-
sists in the reaction of [Ti(C5Me5)Cl3] with the lithium
salt [Li{OC6H3(OMe)(C3H5)}] [8] that gave 8 as an
orange solid in 90% yield. Complexes 7 and 8 are
1
Analogously to this, the H- and 13C-NMR spectra of
the allyl fragment in complexes 7 and 8 are consistent
with neither intra- nor intermolecular interactions with
the titanium metal [22,23].
2.3. Electrochemical studies
Cyclic voltammograms have been recorded for com-
plexes 1–6 versus the Cp2Fe/Cp2Fe+ couple at a plat-

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S. Are´6alo et al. / Journal of Organometallic Chemistry 592 (1999) 265–270
Table 1
XY)O}]. These simple procedures would be a key step
for the attachment of the titanium complex on phenyl
ether dendrimers via HCl elimination or lithiation/
transmetallation sequences. Analogous reaction with
eugenol or its lithium salt afforded [Ti(C5R5)Cl2-
{OC6H3(OMe)(C3H5)}] (R=H or Me) in high yield.
The synthesis of such complexes containing pendant
allyl groups would allow their introduction on the
surface of organosilicon dendrimers containing SiꢀH
bonds via hydrosilylation reactions.
Cyclic voltammetric data for mono- and dinuclear aryloxy complexes
in THF/[Bu4N][PF6]
Complex
Ec (V) vs. Cp2Fe/Cp2Fe+
1
2
3
4
5
6
7
−1.38 a
−1.50 a
−1.40 a
−1.34 a
−1.52 a
−1.54 a
−1.68 b
−0.86
[Ti(C5H5)Cl3]
4. Experimental
a Reduction potentials since the couple is irreversible.
b Partially reversible process.
All manipulations were performed under an inert
atmosphere of argon using standard Schlenk techniques
or a dry box. Solvents were previously dried and freshly
distilled under argon: tetrahydrofuran and diethyl ether
from sodium benzophenone, toluene from sodium, hex-
ane from sodium–potassium alloy, and methylene chlo-
ride over P2O5. Unless otherwise stated, reagents were
obtained from commercial sources and used as re-
ceived. [Ti(C5H5)Cl3] [27] and [Ti(C5Me5)Cl3] [28] were
prepared according to reported methods.
inum electrode in a THF solution using [Bu4N][PF6] as
supporting electrolyte. They all show two irreversible
overlapped reduction waves. We assume that the irre-
versible reductions are metal centred and the resulting
radical anions are very reactive and decompose rapidly.
The dinuclear derivatives undergo two one-electron re-
duction processes, although it is difficult to distinguish
from a single two-electron transfer when the separation
between the two redox waves is so short [13,14,24]. The
reduction peaks are broad and poorly defined and the
results are summarised in Table 1 for a scan rate of 200
mV s−1. Comparing these data with that of the
[Ti(C5H5)Cl3], replacement of one chlorine atom by an
aryloxy ligand makes the reduction potential more neg-
ative by a value of ca. 0.50–0.60 V. It has been
proposed that the formal potentials for the TiIV/TiIII
couples are insensitive to the substituents of the phenyl
ring in aryloxy complexes [25,26]. In our case, the
slightly different results could be attributed to both the
overlapping processes and some degree of interaction
between the metal centres. Identical rationalisation
have been described for other homodinuclear systems
containing Group 5 metals [13,14]. A cyclic voltam-
mogram has also been carried out for compound 7
which, under analogous conditions, exhibits a reversible
wave at potential −1.68 V. The reversibility decreases
as scan rate decreases. These results show that the
titanium metal centre in 7 is slightly more electron rich
than in the related homodinuclear complexes 1–6.
IR spectra were recorded in Nujol mulls between CsI
pellets over the range 4000–200 cm−1 on a Perkin–
1
Elmer 583 spectrophotometer. H- and 13C-NMR spec-
tra were recorded on a Varian Unity VXR-300 or
Varian Unity 500 Plus instruments. Chemical shifts (l
1
ppm) were measured relative to residual H and 13C
resonances for chloroform-d1 used as solvent. C, H and
N analyses were carried out with a Perkin–Elmer 240 C
microanalyzer. Cyclic voltammetry measurements were
carried out under dry argon using distilled and dried
THF as solvent. [Bu4N][PF6] (0.2 M) was used as
supporting electrolyte. A three-platinum-electrode cell
and ferrocene as internal reference were used. Measure-
ments were made using an AMEL 553 Potentiostat, an
AMEL 567 wave generator and recorded on an AMEL
863 recorder.
4.1. Synthesis of [{Ti(C5H5)Cl2}2{v-O(C6H4)O}] (1)
A solution of [Ti(C5H5)Cl3] (1.00 g, 4.56 mmol) in
Et2O (50 ml) was slowly cannulated into a solution of
hydroquinone (0.25 g, 2.3 mmol) in Et2O (20 ml). An
orange solid precipitated and the mixture was stirred
overnight at r.t. Then, the solution was filtered off
through Celite, and the solid was dried under vacuum
affording 1 as an orange microcrystalline solid (0.92 g,
85% yield). Complex 1 can be purified by washing with
several small portions of toluene. Anal. Calc. for
C16H14Cl4O2Ti2: C, 40.39; H, 2.97. Found: C, 40.44; H,
2.98%. IR (Nujol, CsI): 1629 (w), 1225 (s), 1096 (w),
1020 (m), 909 (s), 486 (m), 438 (s), 419 (m), 389 (m).
1H-NMR (CDCl3): l 6.92 (s, 4H, C6H4), 6.78 (s, 10H,
3. Conclusions
Treatment of [Ti(C5H5)Cl3] with hydroquinones
cleanly afforded new homodinuclear aryloxy complexes
[{Ti(C5H5)Cl2}2{m-O(C6H2XY)O}] without the use of
their dilithium salts or auxiliary amines for chloro
abstraction, while in the case of [Ti(C5Me5)Cl3], their
dilithium salts must be used for the synthesis of the
corresponding complexes [{Ti(C5Me5)Cl2}2{m-O(C6H2-

S. Are´6alo et al. / Journal of Organometallic Chemistry 592 (1999) 265–270
269
C5H5). 13C{1H}-NMR (CDCl3): l 120.9 (C5H5), 119.2
(C6H4). Cipso not observed.
[Ti(C5Me5)Cl3] (0.42 g, 1.4 mmol) and 0.7 mmol of the
dilithium salt of methylhydroquinone [8]. Complex 5
was isolated as orange microcrystals (0.4 g, 90% yield).
Anal. Calc. for C27H36Cl4O2Ti2: C, 51.46; H, 5.71.
Found: C, 52.06; H, 5.97%. IR (Nujol, CsI): 1589 (w),
1221 (s), 1102 (m), 1005 (w), 901 (s), 467 (m), 435 (m),
413 (m). 1H-NMR (CDCl3): l 6.81–6.73 (m, 3H, C6H3),
2.20 (s, 15H, C5Me5), 2.19 (s, 15H, C5Me5%), 2.17 (s, 3H,
4.2. Synthesis of [{Ti(C5H5)Cl2}2{v-O(C6H3Me)O}] (2)
This complex was obtained by the same procedure
described for 1, starting from [Ti(C5H5)Cl3] (0.71 g, 3.2
mmol) and methylhydroquinone (0.20 g, 1.6 mmol)
giving 2 as a red solid (0.63 g, 80% yield). For further
purification, it was washed with CH2Cl2. Anal. Calc. for
C17H16Cl4O2Ti2: C, 41.68; H, 3.29. Found: C, 41.85; H,
3.34%. IR (Nujol, CsI): 1592 (w), 1212 (s), 1011 (m), 904
CH3). 13C{1H}-NMR (CDCl3): l 160.7, 159.6 (Cipso
,
C6H3), 132.9, 132.7, 132.3, 129.3 (C6H3), 121.1 (C5Me5),
120.7 (C5Me5%), 16.8 (CH3), 13.0 (C5Me5), 12.9 (C5Me%).
5
1
4.6. Synthesis of [{Ti(C5Me5)Cl2}2{v-O(C6H2Me2)O}]
(6)
(s), 467 (m), 437 (s), 388 (w). H-NMR (CDCl3): l 6.89
(m, 2H, C6H3), 6.77 (s, 5H, C5H5), 6.76 (s, 5H, C5H%5),
6.73 (m, 1H, C6H3), 2.27 (s, 3H, CH3). 13C{1H}-NMR
(CDCl3): l 164.6, 164.2 (Cipso, C6H3), 120.9 (C5H5),
120.8 (C5H5%), 120.5, 120.3, 119.9, 116.8 (C6H3), 16.9
(CH3).
This complex was prepared by a similar procedure to
that described for 4, starting from [Ti(C5Me5)Cl3] (0.38
g, 1.3 mmol) and 0.65 mmol of the dilithium salt of
dimethylhydroquinone [8]. Complex 6 was isolated as
an orange solid (0.38 g, 90% yield). Anal. Calc. for
C28H38Cl4O2Ti2: C, 52.20; H, 5.90. Found: C, 51.42; H,
5.93%. IR (Nujol, CsI): 1600 (w), 1246 (s), 1095 (m),
4.3. Synthesis of [{Ti(C5H5)Cl2}2{v-O(C6H2Me2)O}]
(3)
1
1021 (w), 921 (s), 462 (s), 418 (s), 391 (m). H-NMR
This complex was obtained by the same procedure
described for 1, starting from [Ti(C5H5)Cl3] (0.63 g, 2.9
mmol) and 2,3-dimethylhydroquinone (0.20 g, 1.4
mmol) to give 3 as a red solid (0.60 g, 82% yield)). For
further purification it was washed with toluene. Anal.
Calc. for C18H18Cl4O2Ti2: C, 42.90; H, 3.60. Found: C,
43.03; H, 3.65%. IR (Nujol, CsI): 1592 (w), 1212 (s),
1108 (m), 1011 (m), 904 (s), 467 (m), 438 (s), 389 (w).
1H-NMR (CDCl3): l 6.81 (s, 2H, C6H2), 6.75 (s, 10H,
C5H5), 2.21 (s, 6H, CH3). 13C{1H}-NMR (CDCl3): l
164.1 (Cipso, C6H2), 120.7 (C5H5), 120.4, 117.5 (C6H2),
13.3 (CH3).
(CDCl3): l 6.72 (s, 2H, C6H2), 2.18 (s, 30H, C5Me5),
2.16 (s, 6H, CH3). 13C{1H}-NMR (CDCl3): l 159.3
(Cipso, C6H2), 132.6, 132.1 (C6H2), 118.4 (C5Me5), 13.1
(CH3), 12.9 (C5Me5).
4.7. Synthesis of
[Ti(C5H5)Cl2{O[C6H3(OMe)(CH2CHꢁCH2)]}] (7)
A solution of [Ti(C5H5)Cl3] (1.00 g, 4.56 mmol) in
toluene (40 ml) was slowly added to a solution of
eugenol (0.75 g, 4.56 mmol) in toluene (20 ml). The
mixture was heated at 80°C for 5 h and subsequently
stirred overnight at r.t. Then, the solvent was removed
at reduced pressure, to obtain a red oil. The product was
washed with hexane to leave 7 as red microcrystals (1.26
g, 80% yield). Anal. Calc. for C15H16Cl2O2Ti: C, 51.91;
H, 4.65. Found: C, 52.36; H, 4.83%. IR (Nujol, CsI):
1593 (w), 1277 (s), 1228 (s), 1031 (m), 889 (s), 452 (m),
4.4. Synthesis of [{Ti(C5Me5)Cl2}2{v-O(C6H4)O}] (4)
A solution of [Ti(C5Me5)Cl3] (0.80 g, 2.8 mmol) in
methylene chloride (30 ml) was added to 1.4 mmol of
the dilithium salt of hydroquinone [8]. The reaction
mixture was stirred for 12 h and then filtered through
Celite to remove LiCl. The resulting orange solution
was evaporated under reduced pressure and cooled to
−40°C, to give 4 as orange microcrystals (0.77 g, 90%
yield). Anal. Calc. for C26H34Cl4O2Ti2: C, 50.72; H,
5.52. Found: C, 50.46; H, 5.51%. IR (Nujol, CsI): 1550
(w), 1223 (s), 1089 (w), 1023 (m), 909 (s), 481 (m), 446
1
413 (s). H-NMR (CDCl3): l 6.92 (m, 1H, C6H3), 6.74
(s, 5H, C5H5), 6.72–6.65 (m, 2H, C6H3), 5.90 (m, 1H,
CH2ꢀCHꢁCH2), 5.07 (m, 2H, CH2ꢀCHꢁCH2), 3.86 (s,
3H, OMe), 3.34 (m, 2H, CH2ꢀCHꢁCH2); 13C{1H}-
NMR (CDCl3): l 157.4 (Cipso bonded to ꢀOTi), 150.0
(Cipso bonded to ꢀOMe), 137.1 (Cipso bonded to ꢀC3H5),
137.0 (CH2ꢀCHꢁCH2), 121.1 (C5H5), 120.5, 119.1
(C6H3), 116.2 (CH2ꢀCHꢁCH2), 113.2 (C6H3), 56.4
(OMe), 40.1 (CH2ꢀCHꢁCH2).
1
(m), 339 (w). H-NMR (CDCl3): l 6.85 (s, 4H, C6H4),
2.20 (s, 30H, C5Me5). 13C{1H}-NMR (CDCl3): l 160.8
(Cipso
, C6H4), 133.1 (C6H4), 120.1 (C5Me5), 13.0
(C5Me5).
4.8. Synthesis of [Ti(C5Me5)Cl2{O[C6H3(OMe)-
(CH2CHꢁCH2)]}] (8)
4.5. Synthesis of [{Ti(C5Me5)Cl2}2{v-O(C6H3Me)O}]
(5)
4.8.1. Method A
This complex was prepared by a similar procedure to
that described above for complex 4, starting from
A solution of [Ti(C5Me5)Cl3] (0.35 g, 1.2 mmol) in
diethyl ether (20 ml) was added over a diethyl ether

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S. Are´6alo et al. / Journal of Organometallic Chemistry 592 (1999) 265–270
Advanced Organometallic Chemistry, vol. 33, Academic Press,
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solution (10 ml) of the lithium salt of eugenol [8]. The
reaction mixture was stirred overnight and then filtered
leading to an orange solution that was evaporated to
dryness to give complex 8 as an oily orange solid (0.45
g, 90% yield).
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standard procedures: in a typical experiment, over a solution of
the alcohol ligand in diethyl ether one or two equivalents of
LinBu was added.
4.8.2. Method B
In a sealed NMR tube was placed a solution of
[Ti(C5Me5)Cl3] (0.015 g, 0.066 mmol) in chloroform-d1
and eugenol (10 ml, 0.066 mmol). The reaction mixture
was heated at 100°C during 2 h, then the inert atmo-
sphere of the tube was replaced by vacuum, in order to
remove the HCl formed, and the tube was heated to
100°C for an additional 30 min, to give 8 in quantitative
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1
Found: C, 57.09; H, 6.02%. H-NMR (CDCl3): l 6.90
(m, 1H, C6H3), 6.69–6.62 (m, 2H, C6H3), 5.87 (m, 1H,
CH2CHꢁCH2), 5.04 (m, 2H, CH2CHꢁCH2), 3.80 (s, 3H,
OMe), 3.33 (m, 2H, CH2CHꢁCH2), 2.18 (s, 15H,
C5Me5). 13C{1H}-NMR (CDCl3): l 153.6 (Cipso bonded
to ꢀOTi), 150.0, (Cipso bonded to ꢀOMe), 137.8 (Cipso
bonded to ꢀC3H5), 137.4 (CH2ꢀCHꢁCH2), 135.6, 132.7
(C6H3), 120.3 (C5Me5), 115.8 (CH2ꢀCHꢁCH2), 113.2
(C6H3), 56.3 (OMe), 40.0 (CH2ꢀCHꢁCH2), 12.7
(C5Me5).
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Acknowledgements
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The authors acknowledge DGICYT (project PB97-
0765), University of Alcala´ (project E020/98 and E040/
99) and The Royal Society of Chemistry of UK for
financial support.
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