Synthesis and characterisation of Group 4 metallocene alkoxide complexes. X-ray crystal structure of Cp*2ZrCl(OCH2CH2SPh)

Article abstract of DOI:10.1016/S0022-328X(00)00336-3

Halo-alkoxide zirconocene complexes (η⁵-C₅Me₅)₂ZrCl(OCH ₂CH₂SPh) (1) and (η⁵-C₅Me₅)₂ZrCl(OC ₆H₄SH) (2) have been prepared b

Full text of DOI:10.1016/S0022-328X(00)00336-3

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Journal of Organometallic Chemistry 606 (2000) 156–162
Synthesis and characterisation of Group 4 metallocene alkoxide
complexes. X-ray crystal structure of Cp*ZrCl(OCH2CH2SPh)
2
Rosa Fandos *a,1, Carolina Herna´ndez a, Antonio Otero *b,2, Ana Rodr´ıguez b,
Maria Jose´ Ruiz a, Pilar Terreros c
a Departamento de Qu´ımica Inorga´nica, Orga´nica y Bioqu´ımica, Facultad de Ciencias del Medio Ambiente, Uni6ersidad de Castilla-La Mancha,
A6d. Carlos III s/n, 45071 Toledo, Spain
b Departamento de Qu´ımica Inorga´nica, Facultad de Qu´ımica, Campus de Ciudad Real, Uni6ersidad de Castilla-La Mancha,
13071 Ciudad Real, Spain
c Instituto de Cata´lisis y Petroleoqu´ımica, CSIC, Cantoblanco, 28049 Madrid, Spain
Received 17 March 2000; accepted 19 May 2000
Abstract
Halo-alkoxide zirconocene complexes (h5-C5Me5)2ZrCl(OCH2CH2SPh) (1) and (h5-C5Me5)2ZrCl(OC6H4SH) (2) have been
prepared by reaction of the corresponding zirconocene dichloride with HOCH2CH2SPh or HOC6H4SH, respectively, in the
presence of NEt3. The molecular structure of 1 has been determined by X-ray diffraction studies. Alkyl- and aryl-containing
species (h5-C5Me5)2ZrMe(OCH2CH2SPh) (3) and (h5-C5Me5)2ZrPh(OCH2CH2SPh) (4) were synthesised by reaction of the
corresponding dialkyl or diaryl species with HOCH2CH2SPh, or by reaction of complex 1 with LiMe or LiPh, respectively.
Finally, the dialkoxide complexes L2M(OCH2CH2SR)2 [L=h5-C5H5, M=Ti, R=Ph (5); L=h5-C5Me5, M=Ti, R=Ph (6);
L=h5-C5Me5, M=Ti, R=Me (7)] were prepared by reaction of the appropriate dichloride and alcohol in the presence of NEt3,
and (h5-C5H5)2Zr(OCH2CH2SMe)2 (8) was synthesised by reacting (h5-C5H5)2ZrMe2 with two equivalents of HOCH2CH2SMe.
© 2000 Elsevier Science S.A. All rights reserved.
Keywords: Titanocene; Zirconocene; Alkoxide
chemistry of metal complexes. Under appropriate con-
ditions, the remaining donor atom can coordinate re-
1. Introduction
versibly to the metal centre and temporarily block a
vacant coordination site [4,5]. As a result, it seems
possible to stabilise highly reactive intermediates in
catalytic reactions and to increase their lifetimes. An-
other important feature of the additional donor func-
tion is the possibility of fixing catalytically active
complexes on surfaces that have been functionalised
previously. Finally, this class of ligand could be appro-
priate to stabilise heterometallic complexes. In this re-
spect, HOCH2CH2SR are interesting ligands that
contain both a hard oxygen donor and a soft sulfur
donor and can therefore act easily as bridging ligands
for an early and a late transition metal to yield a
heterometallic complex. In this paper we report the
synthesis and structural characterisation of several
families of zirconocene and titanocene complexes con-
taining this type of ligand.
Early-metal oxides such as titania and zirconia are
often employed as support materials for heterogeneous
catalysts [1,2]. The support may act simply as a disper-
sant for the late-metal centres or may play an active
role in the catalytic cycle. The latter situation gives rise
to the phenomenon known as strong metal support
interactions (SMSI).
The similarity of metal alkoxide species to metal
oxides and the propriety of such species as models for
metal–oxide surfaces has promoted extensive research
into this field [3].
Furthermore, ligand systems with two different
donor atoms are attracting increased interest in the
1 *Corresponding author.
2 *Corresponding author: Tel.: +34-26-295326; fax: +34-26-
295318; e-mail: aotero@qino-cr.uclm.es
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00336-3

R. Fandos et al. / Journal of Organometallic Chemistry 606 (2000) 156–162
157
2. Experimental
CꢀO), 164.6 (s, CꢀS). Anal. Calc. for C26H35OSZrCl: C,
59.74; H, 6.70. Found: C, 60.16; H, 6.68%.
2.1. General procedures
2.4. Synthesis of Cp*ZrMe(OCH2CH2SPh) (3)
2
All reactions were carried out under nitrogen using
standard vacuum line techniques. Toluene was distilled
from sodium, pentane was distilled from sodium–
potassium alloy and diethyl ether and THF were dis-
tilled from sodium–benzophenone. All solvents were
deoxygenated prior to use.
2.4.1. Method (a)
To a solution of Cp*ZrMe2 (0.078 g, 0.20 mmol) in 6
2
ml of pentane was added HOCH2CH2SPh (0.027 ml,
0.20 mmol). The mixture was stirred at room tempera-
ture for 1 h. The solvent was partially evaporated under
vacuum and the solution was cooled to −30°C to yield
a white crystalline solid that was filtered off and charac-
terised as 3 (0.032 g, 30%).
The following reagents were prepared by literature
procedures: Cp*2 ZrCl2 [6], Cp*ZrMe2 [7], Cp*ZrPh2 [7].
2
2
The commercially available compounds MeLi in diethyl
ether, Cp2ZrCl2, Cp2TiCl2, nBuLi, PhLi, HOCH2-
CH2SPh, HOCH2CH2SMe, NEt3, and 4-HO–C6H4SH
were used as received from Aldrich.
2.4.2. Method (b)
IR spectra were recorded on a Perkin–Elmer PE
To a solution of Cp*ZrCl(OCH2CH2SPh) (0.358 g,
2
1
883IR spectrophotometer. H- and 13C-NMR spectra
0.65 mmol) in 10 ml of toluene was added MeLi (0.487
ml, 0.78 mmol) and the mixture was stirred at 70°C for
4 h. The solvent was removed under vacuum and the
residue was extracted with pentane to yield 0.148 g
(44%) of complex 3. IR (Nujol–PET, cm−1): 1119 (vs),
were obtained on either Gemini 200 or Unity 300 MHz
Varian Fourier transform spectrometers. Trace
amounts of protonated solvents were used as refer-
ences, and chemical shifts are reported in units of parts
per million (ppm) relative to SiMe4. Microanalyses were
carried out with a Perkin–Elmer 2400 microanalyzer.
1
1019 (w), 689 (m), 567 (w). H-NMR (C6D6): l −0.16
(s, 3H, CH3), 1.73 (s, 30H, Cp*), 2.88 (m, 2H, CH2S),
4.16 (m, 2H, CH2O), 6.87–7.34 (m, 5H, Ph). 13C{1H}-
NMR (C6D6): l 11.3 (s, Cp*), 27.9 (s, CH3), 36.4 (s,
CH2S), 68.5 (s, CH2O), 117.4 (s, Cp*), 125.8, 129.1,
129.2 (s, CH), 137.5 (s, Cipso). Anal. Calc. for
C29H42OSZr: C, 65.68; H, 7.92. Found: C, 65.31; H,
8.07%.
2.2. Synthesis of Cp*ZrCl(OCH2CH2SPh) (1)
2
To a solution of Cp*ZrCl2 (1.000 g, 2.31 mmol) in 15
2
ml of toluene were added NEt3 (0.320 ml, 2.31 mmol)
and HOCH2CH2SPh (0.31 ml, 2.31 mmol). After stir-
ring for 3 h at 60°C, the suspension was filtered and the
solution was evaporated to dryness under vacuum to
yield complex 1. IR (Nujol–PET, cm−1): 1110 (vs), 546
2.5. Synthesis of Cp*ZrPh(OCH2CH2SPh) (4)
2
1
(m), 335 (m). H-NMR (C6D6): l 1.78 (s, 30H, Cp*),
2.5.1. Method (a)
3.06 (m, 2H, CH2S), 4.30 (m, 2H, CH2O), 6.88–7.38
(m, 5H, Ph). 13C{1H}-NMR (C6D6): l 11.6 (s, Cp*),
35.7 (s, CH2S), 70.3 (s, CH2O), 121.3 (s, Cp*), 125.8,
129.1, 129.3 (s, CH), 137.3 (s, Cipso). Anal. Calc. for
C28H39OSClZr: C, 61.05; H, 7.08. Found: C, 61.33; H,
7.05%.
To a solution of Cp*ZrCl(OCH2CH2SPh) (0.367 g,
2
0.66 mmol) in 12 ml of toluene was added PhLi (0.445
ml, 0.80 mmol) and the mixture was stirred at 75°C for
4 h. The solvent was removed under vacuum and the
residue was extracted with pentane to yield an oily
yellow compound, which was characterised as complex
4 (0.325 g, 83%).
2.3. Synthesis of Cp*ZrCl(OC6H4-4-SH) (2)
2
To a suspension of Cp*ZrCl2 (0.275 g, 0.63 mmol) in
2.5.2. Method (b)
2
8 ml of THF were added, at room temperature, NEt3
(0.088 ml, 0.63 mmol) and 4-hydroxythiophenol (0.080
g, 0.63 mmol). The mixture was stirred for 6 h at room
temperature, filtered and the solvent removed under
vacuum to yield an oily residue. This residue was
purified by washing with pentane to give 0.296 g (90%)
of a white solid, which was characterised as complex 2.
IR (Nujol–PET, cm−1): 1566 (vs), 1151 (m), 1070 (w),
To a solution of Cp*ZrPh2 (0.091 g, 0.17 mmol) in 6
2
ml of toluene was added HOCH2CH2SPh (0.047 ml,
0.35 mmol). The mixture was stirred at 90°C for 7 h
and the solvent was removed under vacuum to yield an
oily compound, which was characterised as 4. IR (Nu-
jol–PET, cm−1): 1585 (m), 1273 (m), 1114 (vs), 1057
(m), 1051 (m), 764 (m), 554 (s), 497 (s), 490 (s), 474 (m).
1H-NMR (C6D6): l 1.62 (s, 30H, Cp*), 3.15 (m, 2H,
CH2S), 4.35 (m, 2H, CH2O), 7.01–7.47 (m, 10H, Ph).
13C{1H}-NMR (C6D6): l 13.3 (s, Cp*), 38.4 (s, CH2S),
70.8 (s, CH2O), 120.7 (s, Cp*), 126.1, 127.8, 128.9,
130.9, 131.2, 139.8 (s, CH), 140.4, 192.3 (s, Cipso).
1
867 (s), 836 (s), 534 (w). H-NMR (C6D6): l 1.77 (s,
30H, Cp*), 6.63 (m, 2H, OC6H4SH), 7.43 (m, 2H,
OC6H4SH). 13C{1H}-NMR (C6D6): l 11.7 (s, Cp*),
122.6 (s, Cp*), 119.1, 134.6 (s, OC6H4SH), 125.9 (s,

158
R. Fandos et al. / Journal of Organometallic Chemistry 606 (2000) 156–162
2.6. Synthesis of Cp2Ti(OCH2CH2SPh)2 (5)
10H, Ph). 13C{1H}-NMR (C6D6): l 12.4 (s, Cp*), 36.9
(s, CH2S), 77.7 (s, CH2O), 126.3 (s, Cp*), 129.1, 129.2,
129.9 (s, CH), 136.2 (s, Cipso). Anal. Calc. for
C36H48O2S2Ti: C, 69.21; H, 7.74. Found: C, 68.84; H,
7.69%.
To a solution of Cp2TiCl2 (0.500g, 2.01 mmol) in 15
ml of toluene were added NEt3 (0.56 ml, 4.03 mmol)
and HOCH2CH2SPh (0.54 ml, 4.03 mmol). The mixture
was stirred for 16 h at room temperature. The ammo-
nium salt was then separated by filtration. The solvent
was removed under vacuum and the residue washed
twice with pentane (2×8 ml) to yield 0.584 g (60%) of
complex 5. IR (Nujol–PET, cm−1): 1098 (s), 1010 (w),
2.8. Synthesis of Cp*Ti(OCH2CH2SMe)2 (7)
2
To a solution of Cp*TiCl2 (0.307 g, 0.78 mmol) in 15
2
ml of toluene were added NEt3 (0.219 ml, 1.50 mmol)
and HOCH2CH2SMe (0.265 ml, 3.00 mmol). The solu-
tion was heated at 70°C for 4 h. After filtration, the
solvent was evaporated to dryness and the residue
washed with Et2O at −30°C to give 0.238 g of a
deep-purple crystalline solid, which was characterised
as complex 7 (0.238 g, 61%). IR (Nujol–PET, cm−1):
1072 (vs), 1039 (m), 1018 (s), 776 (m), 573 (s), 410 (m).
1H-NMR (C6D6): l 1.77 (s, 30H, Cp*), 1.79 (s, 6H,
SCH3), 2.61 (m, 4H, CH2S), 4.36 (m, 4H, CH2O).
13C{1H}-NMR (C6D6): l 12.4 (s, Cp*), 13.0 (s, SꢀCH3),
38.3 (s, CH2S), 78.3 (s, CH2O), 124.9 (s, Cp*). Anal.
Calc. for C26H44O2S2Ti: C, 62.30; H, 8.78. Found: C,
61.84; H, 8.79%.
1
823 (m), 810 (s), 585 (w). H-NMR (C6D6): l 2.85 (t,
3
3
4H, JH–H=7.3 Hz, CH2S), 4.38 (t, 4H, JH–H=7.3
Hz, CH2O), 5.84 (s, 10H, Cp), 6.88–7.32 (m, 10H, Ph).
13C{1H}-NMR (C6D6): l 36.2 (s, CH2S), 80.1 (s,
CH2O), 116.6 (s, Cp), 125.8, 129.1, 129.2 (s, CH), 137.7
(s, Cipso). Anal. Calc. for C26H28O2S2Ti: C, 64.45; H,
5.82. Found: C, 63.97; H, 5.77%.
2.7. Synthesis of Cp*Ti(OCH2CH2SPh)2 (6)
2
To a solution of Cp*TiCl2 (0.211 g, 0.54 mmol) in 10
2
ml of toluene were added NEt3 (0.152 ml, 1.09 mmol)
and HOCH2CH2SPh (0.147 ml, 1.09 mmol). The result-
ing solution was stirred at 60°C for 4 h. After filtration
the solvent was evaporated to dryness and the residue
washed with pentane to give complex 6 (0.168 g, 50%).
IR (Nujol–PET, cm−1): 1146 (m), 1063 (m), 572 (m),
2.9. Synthesis of Cp2Zr(OCH2CH2SMe)2 (8)
A solution of Cp2ZrMe2 (0.250 g, 1.02 mmol) in 10
ml of pentane was stirred with HOCH2CH2SMe (0.134
ml, 1.54 mmol) at room temperature for 72 h. A white
solid was obtained, which was separated by filtration
and identified as 8 (0.090 g, 22%). IR (Nujol–PET,
1
405 (m). H-NMR (C6D6): l 1.76 (s, 30H, Cp*), 3.04
(m, 4H, CH2S), 4.41 (m, 4H, CH2O), 7.01–7.38 (m,
Table 1
1
cm−1): 1014 (m), 819 (m), 796 (s), 521 (m). H-NMR
Crystal data and structure refinement for 1
3
(C6D6): l 1.85 (s, 6H, SCH3), 2.52 (t, 4H, JH–H=6.9
Empirical formula
Formula weight
Temperature (K)
C28H39ClOSZr
550.32
293(2)
Hz, CH2S), 4.08 (t, 4H, 3JH–H=6.9 Hz, CH2O), 6.02 (s,
10H, Cp). 13C{1H}-NMR (C6D6): l 15.9 (s, SꢀCH3),
38.8 (s, CH2S), 72.1 (s, CH2O), 112.1 (s, Cp). Anal.
Calc. for C16H24O2S2Zr: C, 47.56; H, 5.94. Found: C,
46.57; H, 5.59%.
,
Wavelength (A)
0.7107
Monoclinic
P21/n
Crystal system
Space group
Unit cell dimensions
,
a (A)
8.541(9)
2.10. X-ray structural determination of complex 1
,
b (A)
17.339(2)
18.619(5)
102.21(5)
2695(3)
,
c (A)
i (°)
V (A )
Crystal, data collection, and refinement parameters
are collected in Table 1. Suitable crystals were selected
and mounted on a fine glass fibre with epoxy cement.
The unit cell parameters were each determined from the
angular setting of least-squares fit of 25 strong high-
angle reflections. The asymmetric unit contained one
independent molecule. Reflections were collected at
25°C on a NONIUS-MACH3 diffractometer equipped
with a graphite monochromated radiation source (u=
3
,
Z
4
Dcalc (g cm−3
)
1.356
6.0
1152
Absorption coefficient (cm−1
)
F(000)
q Range for data collection (°)
Index ranges
2.24–26.99
05h510, 05k522,
−235l523
5871
5871/0/290
1.208
R1=0.0707,
wR2=0.2433
1.524 and −2.119
Reflections collected
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I\2|(I)] a
,
0.71073 A). The sample showed no significant intensity
decay over the duration of data collection.
Data were corrected in the usual fashion for Lorentz
and polarisation effects and empirical absorption was
applied [8]. The space group was determined from the
systematic absences in the diffraction data. The struc-
Largest difference peak and hole
(e A
−3
,
)
a R1=ꢀꢁꢁFoꢁꢁ−ꢁꢁFcꢁꢁ/ꢀꢁFoꢁ; wR2=[ꢀ[w(F2o−Fc2)2]/ꢀ[w(F2o)2]]0.5
.

R. Fandos et al. / Journal of Organometallic Chemistry 606 (2000) 156–162
159
Scheme 1.
tures were solved by direct methods [9] and refinements
on F2 were carried out by full-matrix least-squares
analysis [10]. Anisotropic temperature parameters were
considered for all non-hydrogen atoms, while hydrogen
atoms were included in calculated positions but not
refined. Final disagreement indices are R1=0.0707,
phenyl group resonates at 137.0 ppm. In the IR spec-
trum it is worth noting that the expected band corre-
sponding to w(ZrꢀO) appears at 546 cm−1
.
In order to confirm the proposed structural disposi-
tion, the molecular structure of complex 1 was solved
by X-ray diffraction analysis. An ORTEP view of the
molecule with the atom labelling scheme is shown in
Fig. 1. Selected bond lengths and angles are given in
Table 2.
wR2=0.2433, largest difference peak and hole 1.524
−3
,
and −2.119 e A
.
The crystal structure consists of discrete molecules
with no unusually short intermolecular distances. The
complex exhibits the typical bent metallocene structure.
The cyclopentadienyl rings are tilted by 44.2(2)° with
respect to one another and are bonded to the zirconium
atom in an almost symmetric h5-fashion. The
Zr(1)ꢀCE(1) and Zr(1)ꢀCE(2) (CE=ring centroid) dis-
3. Results and discussion
Reaction of Cp*ZrCl2 (Cp*=h5-C5Me5) with one
2
equivalent of 2-phenyl-mercaptoethanol in the presence
of NEt3 yields the monomeric complex 1 (Scheme 1).
The same reaction in the presence of an excess of ligand
and NEt3 yielded the same product. It seems that
substitution of the second chloride ion is not possible
using this procedure. The inertness of the second chlo-
ride toward substitution has already been observed in
,
tances of 2.2703(6) and 2.2596(7) A compare well with
those of other Cp2Zr(IV) complexes [12].
similar reactions [11]. In the same way, Cp*ZrCl2 re-
2
acts, at room temperature, with 4-hydroxythiophenol in
the presence of NEt3 to yield Cp*ZrCl(OC6H4SH) (2)
2
(Scheme 1).
1
Complexes 1 and 2 have been characterised by H-
and 13C-NMR spectroscopy (see Section 2). In both
cases, the NMR spectra indicate that the alkoxide
ligand is acting in a monodentate fashion. As an exam-
1
ple, the H-NMR spectrum of 1 shows multiplet signals
at 3.06 and 4.30 ppm, which are assigned to the methyl-
ene protons bonded to the sulfur and the oxygen atoms,
respectively. The Cp* ligand gives rise to a singlet at
1.78 ppm, indicating that both rings are equivalent, and
the phenyl group shows two multiplet signals at 6.88
and 7.38 ppm. The 13C-NMR spectrum of 1 exhibits
signals for methylene carbon atoms at 35.7 and 70.3
ppm and these are the carbons bonded to the sulfur and
oxygen atoms, respectively. In addition, the Cipso of the
Fig. 1. Perspective ORTEP drawing of the molecular structure complex
1.

160
R. Fandos et al. / Journal of Organometallic Chemistry 606 (2000) 156–162
Table 2
CH2SPh) (4) were prepared either by a protonolysis
reaction of the corresponding dialkyl derivatives
,
Selected bonds distances (A) and angles (°) for 1
Cp*Zr(R)2
(R=Me,
Ph)
with
the
alcohol
2
Bond angles
Zr(1)ꢀCE(1)
Zr(1)ꢀCE(2)
Zr(1)ꢀO(4)
Zr(1)ꢀCl(2)
S(3)ꢀC(7)
S(3)ꢀC(6)
O(4)ꢀC(5)
C(5)ꢀC(6)
HOCH2CH2SPh, or through a metathesis reaction of 1
with the appropriate lithium salt (MeLi or PhLi, respec-
tively) (Scheme 2). In the first procedure complexes 3
and 4 were isolated even when a large excess of the
alcohol was used. Nevertheless, complex 4 was always
found to contain small amounts of HOCH2CH2SPh as
an impurity, even when a 1:1 ratio of reactants was
used. Both complexes were characterised spectroscopi-
2.2703(6)
2.2596(7)
1.930(5)
2.468(3)
1.756(8)
1.801(8)
1.395(8)
1.484(11)
Bond distances
O(4)ꢀZr(1)ꢀCl(2)
C(7)–S(3)ꢀC(6)
C(5)ꢀO(4)ꢀZr(1)
O(4)ꢀC(5)ꢀC(6)
C(5)ꢀC(6)ꢀS(3)
1
cally. The H-NMR spectra of 3 and 4 exhibit a singlet
94.3(2)
106.6(4)
162.9(6)
111.6(6)
113.7(6)
at ca. 1.70 ppm for the methyl protons of the Cp* ring
as well as two triplet signals at ca. 3.00 and 4.20 ppm,
which are assigned to the methylene protons bonded to
the sulfur and the oxygen atoms, respectively, of the
alkoxide ligand. In addition, the methyl group for
complex 3 resonates at −0.16 ppm, while the reso-
nances for the phenyl groups in complex 4 appear
between 6.87 and 7.34 ppm as a series of multiplet
signals. The 13C-NMR spectra show methylene carbon
resonances at ca. 37.0 and 70.0 ppm for the carbons
bonded to the sulfur and oxygen atoms, respectively.
The resonance for the methyl group bonded to the
zirconium atom in 3 appears at 27.9 ppm. Finally, the
expected band in the IR spectra for w(ZrꢀO) appears at
ca. 500 cm−1 (see Section 2). These spectroscopic data
are in agreement with
analogous to that found in complex 1, in which the
alkoxide behaves as a monodentate ligand.
The reactions of Cp2TiCl2 and Cp*TiCl2 with 2-
phenylmercaptoethanol were also considered. These
complexes react with HOCH2CH2SPh in the presence
of NEt3 to yield the corresponding dialkoxide deriva-
The Zr atom is bonded exclusively to the alkoxide
ligand through the O(4) atom with a bond distance of
1.930(5) A. This value falls into the range expected
(1.92–2.00 A) for zirconium alkoxide complexes [2,13]
and is close to the ZrꢀO bond length found in the
analogous mono-chloro complex Cp2ZrCl(OCH2-
,
,
,
CH2SPh) [1.921(2) A] [14], although the Zr(1)ꢀO(4)ꢀ
C(5) angle is rather large [162.9(6)°]. These data indi-
cate that an appreciable p-contribution from electronic
donation of the oxygen atom to the ZrꢀO bond must be
considered. Finally, the phenyl ring of the mercaptane
moiety is twisted with respect to the coordination plane,
defined by the plane Zr(1)ꢀO(4)ꢀCl(2), with a dihedral
angle of 41.9(2)°. No interaction between the sulfur and
the zirconium atoms is observed, which is in agreement
with proposed structural disposition.
a
structural disposition
2
The synthesis of alkyl(aryl)-alkoxide-containing zir-
conocene complexes was also considered. Complexes
Cp*Zr(CH3)(OCH2CH2SPh) (3) and Cp*ZrPh(OCH2-
tives
Cp2Ti(OCH2CH2SPh)2
(5)
and
Cp*Ti-
2
(OCH2CH2SPh)2 (6), respectively (Scheme 3). How-
ever, while reaction of Cp2TiCl2 takes place at
2
2
Scheme 2.

R. Fandos et al. / Journal of Organometallic Chemistry 606 (2000) 156–162
161
Scheme 3.
room temperature, Cp2*TiCl2 requires a temperature of
60°C to react.
140607. Copies of this information may be obtained
free of charge from The Director, CCDC, 12 Union
Road, Cambridge CB2 LE2, UK (fax: +44-1223-
336033, or e-mail: depositccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
Both complexes were characterised by the usual spec-
1
troscopic techniques. H- and 13C-NMR spectra indi-
cate that there is no interaction between the sulfur atom
and the titanium centre.
It is worth noting that in the case of zirconium it is
not possible, under these experimental conditions, to
substitute the second chlorine atom, but in the case of
titanium, the substitution takes place readily.
In the same way, we also explored the reactivity of
Acknowledgements
We thank the Direccio´n General de Ensen˜anza Supe-
rior e Investigacio´n Cient´ıfica (grant no. PB95-0023-
C01-C02) for financial support and the Junta de
Comunidades de Castilla-La Mancha for a fellowship
(C. Herna´ndez).
Cp*TiCl2 and Cp2ZrMe2 towards 2-methylmercap-
2
toethanol. Reaction of Cp*2 TiCl2 with two equivalents
of the mercaptoethanol, in the presence of NEt3,
yielded the complex Cp*Ti(OCH2CH2SMe)2 (7).
2
Reaction of Cp2ZrMe2 with 2-methylmercap-
toethanol in a 1:2 molar ratio afforded the complex
Cp2Zr(OCH2CH2SMe)2 (8).
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1
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4. Supplementary material
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