Synthesis and reactivity of new silyl-substituted monocyclopentadienyl molybdenum and tungsten complexes

Article abstract of DOI:10.1016/S0022-328X(98)00962-0

The functionalized silylated cyclopentadienyl molybdenum and tungsten complexes [MCp^Cl(CO)₃H] (M=Mo, W; Cp^Cl=η⁵-C₅H₄SiMe₂Cl) are prepared easily from the reaction of [M(CO)₃(NCMe)₃] with C₅H₅SiMe₂Cl in refluxing THF, via C-H activation and H transfer to the metal centre. Metathetical replacement of hydride by chloride is readily achieved when their methylene chloride solutions are treated with a few milliliters of CCl₄ to give the chloro complexes [MCp^Cl(CO)₃Cl] (M=Mo, W). The chloro-molybdenum complexes react with 1/2 equivalent of deoxygenated water to give the corresponding dinuclear complexes [{Mo(CO)₃X}₂(μ-Cp^OCp)], (X=H, Cl; Cp^OCp=η⁵-C₅H₄-SiMe ₂-O-SiMe₂-η⁵-C₅H₄), whereas their reaction with one equivalent of anhydrous LiOH in toluene leads to selective substitution of the silicon-bonded chlorine atom to give the hydroxo complexes [MoCp^OH(CO)₃X] (X=H, Cl; Cp^OH=η⁵-C₅H₄SiMe₂OH). These hydroxosilyl complexes can be transformed into the dinuclear compounds [{Mo(CO)₃X}₂(μ-Cp^OCp)] by heating (50°C, 2 h) or by their reaction with one equivalent of the respective hydrido and chloro derivatives [MoCp^Cl(CO)₃X]. Total decarbonylation of the hydrido compounds results from oxidation with a stoichiometric amount of PCl₅ to give the paramagnetic molybdenum(V) and tungsten(V) complexes [MCp^ClCl₄] (M=Mo, W). Reactions of these complexes with one equivalent of NH₂R in the presence of NEt₃ yield the imido derivatives [MCp^Cl(NR)Cl₂] (M=Mo, R=2,6-Me₂-Ph; M=W, R=^tBu) and subsequent oxidation of the tungsten complex with 1/2 equivalent of PCl₅ gives [WCp^Cl(N^tBu)Cl₃]. Reduction of [MoCp^ClCl₄] with two equivalents of Na/Hg gives the dinuclear molybdenum(III) complex [MoCp^Cl]₂(μ-Cl)₄. All of the reported compounds were characterized by elemental analysis and ¹H- and ¹³C NMR-spectroscopy.

Full text of DOI:10.1016/S0022-328X(98)00962-0

Journal of Organometallic Chemistry 572 (1999) 155–161
Synthesis and reactivity of new silyl-substituted monocyclopentadienyl
molybdenum and tungsten complexes
F. Javier de la Mata, Pilar Giner, Pascual Royo *
Departamento de Qu´ımica Inorga´nica, Uni6ersidad de Alcala´, Campus Uni6ersitario, E-28871 Alcala´ de Henares, Spain
Received 27 April 1998; received in revised form 15 July 1998
Abstract
The functionalized silylated cyclopentadienyl molybdenum and tungsten complexes [MCpCl(CO)3H] (M=Mo, W; CpCl=p5-
C5H4SiMe2Cl) are prepared easily from the reaction of [M(CO)3(NCMe)3] with C5H5SiMe2Cl in refluxing THF, via C–H
activation and H transfer to the metal centre. Metathetical replacement of hydride by chloride is readily achieved when their
methylene chloride solutions are treated with a few milliliters of CCl4 to give the chloro complexes [MCpCl(CO)3Cl] (M=Mo, W).
The chloro–molybdenum complexes react with 1/2 equivalent of deoxygenated water to give the corresponding dinuclear
complexes [{Mo(CO)3X}2(v-CpOCp)], (X=H, Cl; CpOCp=p5-C5H4-SiMe2-O-SiMe2-p5-C5H4), whereas their reaction with one
equivalent of anhydrous LiOH in toluene leads to selective substitution of the silicon-bonded chlorine atom to give the hydroxo
complexes [MoCpOH(CO)3X] (X=H, Cl; CpOH=p5-C5H4SiMe2OH). These hydroxosilyl complexes can be transformed into the
dinuclear compounds [{Mo(CO)3X}2(v-CpOCp)] by heating (50°C, 2 h) or by their reaction with one equivalent of the respective
hydrido and chloro derivatives [MoCpCl(CO)3X]. Total decarbonylation of the hydrido compounds results from oxidation with a
stoichiometric amount of PCl5 to give the paramagnetic molybdenum(V) and tungsten(V) complexes [MCpClCl4] (M=Mo, W).
Reactions of these complexes with one equivalent of NH2R in the presence of NEt3 yield the imido derivatives [MCpCl(NR)Cl2]
(M=Mo, R=2,6-Me2-Ph; M=W, R=tBu) and subsequent oxidation of the tungsten complex with 1/2 equivalent of PCl5 gives
[WCpCl(NtBu)Cl3]. Reduction of [MoCpClCl4] with two equivalents of Na/Hg gives the dinuclear molybdenum(III) complex
1
[MoCpCl]2(v-Cl)4. All of the reported compounds were characterized by elemental analysis and H- and 13C NMR-spectroscopy.
© 1999 Elsevier Science S.A. All rights reserved.
Keywords: Molybdenum; Tungsten; Cyclopentadienyl; Chlorosilyl
1. Introduction
cyclopentadienyl imido Group 6 metal complexes have
been reported also [4] and more recently we published
alternative methods to isolate molybdenum and tung-
sten imido derivatives in high yields [5].
Since the discovery and early investigations of chro-
mocene [1] the study of cyclopentadienyl Group 6 metal
derivatives has played a prominent role. Compounds
containing halide ligands in addition to the Cp ring are
particularly useful as synthons for other organometallic
systems [2]. We reported [3] the synthesis of some
dinuclear hydrido- and chloro-tricarbonyl cyclopentadi-
enyl molybdenum and tungsten complexes of the type
investigated extensively by Legzdins [3]. Lately, p5-
In addition, there has been growing interest in the
development of supported catalytic systems because the
attachment of metal complexes to organic polymers or
inorganic supports [6] combines the most advantageous
properties of both homogeneous and heterogeneous
catalysis. Functionalized silylated cyclopentadienyl
derivatives are good candidates for this purpose. In this
paper, we report an efficient approach for the synthesis
of new silyl-substituted monocyclopentadienyl molyb-
denum and tungsten complexes and describe some as-
* Corresponding author. Tel.: +34-1-8854765; fax: +34-1-
8854683; e-mail: proyo@inorg.alcala.es.
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(98)00962-0

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F. Ja6ier de la Mata et al. / Journal of Organometallic Chemistry 572 (1999) 155–161
as orange crystalline solids, although they become oily
materials after several hours at room temperature.
Complexes 1–4 are soluble in aromatic and saturated
hydrocarbons, methylene chloride and THF are air
and moisture sensitive and have to be stored in rigor-
ously dry, anaerobic conditions. They are thermally
stable and no decomposition was observed below
100°C. Particularly interesting was the thermal decom-
position of complex 3 monitored by 1H-NMR spec-
troscopy, which gave a mixture of [MoCpCl(v-Cl2)]2
(11) and another unidentified product (presumably
[MoCpCl(CO)3]2 or its decomposition product) when
heated for 12 h at 120°C. Identification of complex 11
was made by comparison of its NMR data with that
of a pure sample of 11 prepared by an alternative
method (see below).
pects of the comparative reactivity of their silicon–
chloro and metal–chloro bonds.
2. Results and discussion
2.1. Preparati6e methods
The three acetonitrile ligands in [M(CO)3(NCMe)3]
are substituted easily, with simultaneous ring C–H
activation and hydrogen transfer [7], by reaction with
C5H5SiMe2Cl in refluxing THF to give [MCpCl(CO)3H]
(M=Mo (1) [8], W (2); CpCl=p5-C5H4SiMe2Cl).
Complex 3 contains both Si–Cl and Mo–Cl bonds
each available for substitution reactions. Selective hy-
drolysis of the Si–Cl bond would be desirable in order
to attach these complexes to acidic inorganic oxides as
supports [9]. Hydrolysis reactions were carried out to
investigate the relative reactivity of the Si–Cl and Mo–
Cl bonds in 3 and extended to the hydrido complex 1
(Scheme 2). Both complexes 1 and 3 reacted with 1/2
equivalent of deoxygenated water in toluene with evolu-
tion of HCl, giving the corresponding dinuclear com-
plexes [{Mo(CO)3X}2(v-CpOCp)], (X=H (5), Cl (6);
CpOCp=p5-C5H4-SiMe2-O-SiMe2-p5-C5H4). Selective
hydrolysis of the Si–Cl bond was observed in both
cases even when an excess of water was used. Com-
plexes 5 and 6 were isolated as orange–red solids,
Scheme 1.
Metathetical replacement of hydride by chloride is
readily achieved when methylene chloride solutions of
1 and 2 are stirred with a few milliliters of CCl4,
giving the chloro-complexes [MCpCl(CO)3Cl] (M=Mo
(3), W (4)) (Scheme 1). These complexes are obtained
Scheme 2.

F. Ja6ier de la Mata et al. / Journal of Organometallic Chemistry 572 (1999) 155–161
157
soluble in aromatic hydrocarbons and chlorinated sol-
vents. Complex 6 was air and moisture stable and
both were thermally stable below 150°C. A similar
selective reaction at the Si–Cl bond was observed
when complex 3 was treated with one equivalent of
the stronger nucleophile, anhydrous LiOH in toluene
at room temperature to give the hydroxosilyl complex
[MoCpOH(CO)3Cl] (8) (CpOH=p5-C5H4SiMe2OH),
which was isolated as a red microcrystalline solid in
quantitative yield. An analogous reaction of a ben-
zene-d6 solution of 1 with one equivalent of anhydrous
LiOH in a sealed NMR tube yielded the related hy-
drido complex [MoCpOH(CO)3H] (7), although it was
always contaminated with small amounts of the dinu-
clear compound 5, which prevented isolation of 7 as a
pure compound. Complexes 7 and 8 can be trans-
formed into the dinuclear compounds 5 and 6 on
heating (50°C, 2 h) or by reaction with one equivalent
of 1 and 3, respectively.
We observed no reactivity at the Mo–Cl bond in
the reactions described above. This contrasts with the
behaviour reported for the titanium and niobium
derivatives [10], where both the Si–Cl and the Ti–Cl
bonds were simultaneously involved in reactions with
protic reagents such as water, and reactions with
stronger nucleophilic reagents took place selectively at
the M–Cl bonds. This contrasting behaviour was an-
ticipated since the Lewis acidity of the Mo(II) centre is
lower than the Ti(IV) and Nb(V) centres.
could be reoxydized to 9 by addition of a stoichiomet-
ric amount of PCl5. Complex 11 is an air and mois-
ture sensitive compound, sparingly soluble in aromatic
hydrocarbons and soluble in chlorinated solvents.
Isolation of new cyclopentadienyl molybdenum and
tungsten imido derivatives was attempted by reaction
of complexes 9 and 10 with amines. Reaction of 10
t
with one equivalent of NH2 Bu in the presence of two
equivalents of triethylamine gave, after removing the
ammonium salt formed, [WCpCl(NtBu)Cl2] (12), which
could be oxidised to the diamagnetic tungsten(VI)
derivative [WCpCl(NtBu)Cl3] (13) by addition of 1/2
equivalent of PCl5. Complex 9 also reacted with
NHt2Bu in the presence of NEt3, but in this case the
reaction product could not be characterized and its
reaction with PCl5 did not allow the identification of
any molybdenum(VI) species. Nevertheless, a similar
reaction of 9 with NH2(2,6-Me2-C6H3) afforded the
paramagnetic complex [MoCpCl(N-2,6-Me2-C6H3)Cl2]
(14), which was characterized by elemental analysis
and IR spectroscopy. Subsequent oxidation of 14 with
1/2 equivalent of PCl5 failed and we could not charac-
terize any organometallic product in the resulting mix-
ture (Scheme 3).
Total decarbonylation of the hydrido complexes 1
and 2 was achieved by their oxidation with a stoichio-
metric amount of PCl5 to give the paramagnetic
molybdenum(V)
and
tungsten(V)
complexes
[MCpClCl4] (M=Mo (9), W (10)). However, the
molybdenum complex 9 was obtained better by oxida-
tion of the chloro derivative 3 with PCl5. Complexes 9
and 10 were found to be very moisture sensitive, react-
ing immediately with traces of water, and must be
stored under rigorously dry conditions. They are solu-
ble in aromatic hydrocarbons and chlorinated solvents
but insoluble in saturated hydrocarbons such as n-hex-
ane.
Reduction of 9 with two equivalents of sodium
amalgam (10% of Na) in toluene, followed by extrac-
tion into methylene chloride gave the molybdenum(III)
complex [MoCpCl(v-Cl2)]2 (11) in 70% yield, which
Scheme 3.

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F. Ja6ier de la Mata et al. / Journal of Organometallic Chemistry 572 (1999) 155–161
Table 1
1H-NMR (C6D6)a data for complexes MCp(CO)3X (X=H, Cl)
Complex
–C5H4–
–SiMe2–
MoCpCl(CO)3H (1)
WCpCl(CO)3H (2)
4.75, 4.69 (AA%BB% spin system, 4H)
4.66 (m, 4H)
4.69, 4.52 (AA%BB% spin system, 4H)
4.66 (m, 4H)
4.83, 4.79 (AA%BB% spin system, 4H)
4.84, 4.76 (AA%BB% spin system, 4H)
4.83, 4.76 (AA%BB% spin system, 4H)
4.81, 4.44 (AA%BB% spin system, 4H)
0.32 (s, 6H)
0.32 (s, 6H)
0.41 (s, 6H)
0.41 (s, 6H)
0.17 (s, 6H)
0.23 (s, 6H)
0.11 (s, 6H)
0.22 (s, 6H)
MoCpCl(CO)3Cl (3)
WCpCl(CO)3Cl (4)
[Mo(CO)3H]2(v-CpO) (5)
[Mo(CO)3Cl]2(v-CpO) (6)
MoCpOH(CO)3H (7)
MoCpOH(CO)3Cl (8)
a Chemical shifts are given in ppm. Coupling constants are given in Hz.
2.2. Structural study
eties and four bridging chlorine atoms, similar to the
structure found for related molybdenum complexes
[12]. The small difference found in the H-NMR spec-
trum, between the two signals due to the protons of the
cyclopentadienyl group and its diamagnetic character is
consistent with the presence of a single metal–metal
bond between the two molybdenum centres.
1
Spectroscopic data for all the new complexes re-
ported are given in Section 4. The IR spectra of all
complexes show a characteristic band at 1250 cm−1
due to the SiMe2 group and the new carbonyl com-
plexes show w(CO) frequencies in the expected range for
terminal carbonyl ligands (2050–1900 cm−1). 1H-NMR
data of the new complexes 1–8 are given in Table 1.
These spectra show typical resonances in the range l
4.9–4.6 ppm for the cyclopentadienyl ring protons and
in the range l 0.41–0.11 for the SiMe2 protons. The
upfield shifts of the methyl resonances in complexes
5–8 indicate the replacement of chlorine by oxygen
bonded to silicon. The 13C-NMR data of these com-
plexes (Table 2) also show the selective substitution of
chlorine by oxygen in complexes 5–8, as methyl reso-
nances of these complexes are shifted upfield with re-
spect to the same resonances in complexes 1–4, whereas
no significant differences are observed for the carbonyl
groups of complexes 3, 6 and 8.
3. Conclusions
The synthesis of new chlorodimethylsilyl-substituted
mono cyclopentadienyl tricarbonyl hydrido [MCpCl-
(CO)3H] and chloro [MCpCl(CO)3Cl] molybdenum(II)
and tungsten(II) complexes was carried out following
typical reported procedures. A comparative study of
the reactivity of the two types of Si–Cl and Mo–Cl
bonds present in the molybdenum complex shows that
the Si–Cl bond reacts selectively with water and anhy-
drous LiOH to afford hydroxosilyl complexes
[MoCpOH(CO)3X] due to the lower Lewis acidity of the
molybdenum(II) centre. Oxidation of carbonyl com-
plexes with PCl5 gave the cyclopentadienyl tetrachloro
metal derivatives [MCpClCl4], which were transformed
into the corresponding imido molybdenum(V) and
tungsten(V) complexes [MCpClCl2(NR)] by reaction
with suitable amines in the presence of triethylamine.
Subsequent oxidation with PCl5 was only possible with
the imido tungsten complex to give the new diamag-
netic cyclopentadienyl imido tungsten(VI) derivative
[WCpCl(NtBu)Cl3].
The 1H-NMR spectra of the hydrido complexes show
high-field singlets between l −7.3 and −5.5 ppm with
W satellites resolved for 2. The 13C-NMR spectra of the
hydrido complexes recorded at room temperature show,
in all cases, a unique broad resonance for the carbonyl
carbons, whereas the chloro carbonyl complexes show
two resonances at room temperature. This different
behaviour may be related to the low-energy barriers to
hydride motion between piano stool legs [11].
Complexes 9, 10, 12 and 14 are paramagnetic and
were characterized by their analytical composition and
IR spectra and in the case of 12 by its reactivity to give
1
the diamagnetic complex 13. The H-NMR spectrum of
4. Experimental
complex 13 shows two signals for the protons of the
cyclopentadienyl ring, one singlet at l 1.02 ppm for the
tBu group of the imido ligand and one singlet at l 0.79
ppm for the methyl protons of the SiMe2 group. The
13C-NMR spectrum of 13 is consistent with its formula-
tion as an imido tungsten(VI) complex (see Section 4).
The spectroscopic data for complex 11 suggest a
dimeric structure with terminal cyclopentadienyl moi-
All manipulations were performed under an inert
atmosphere of argon using standard Schlenck tech-
niques or a dry box. Solvents used were dried previ-
ously and freshly distilled under argon: tetrahydrofuran
from sodium benzophenone ketyl; toluene from
sodium; hexane from sodium–potassium; CCl4 over
calcium hydride. Unless otherwise stated, reagents were

F. Ja6ier de la Mata et al. / Journal of Organometallic Chemistry 572 (1999) 155–161
159
colour. The solvent was removed under vacuum and
the resulting brown oil extracted with n-hexane (2×10
ml) to give a yellow–brown oil characterized as 2
(90%). Complex 2 can be isolated in small amounts as
a yellow crystalline solid upon treatment of the oil with
cold hexane (1 ml), although it reverts to an oil after
several hours at room temperature and both oil and
solid show the same chemical behavior. IR (CsI,
cm−1): 2022 s, 1931 s, 1258 s, 1041 m, 806 s, 492 m,
obtained from commercial sources and used as re-
ceived. Amines, NH2t Bu and NH2(2,6-(Me2)-C6H3) were
purchased from commercial sources, dried over calcium
hydride and then purified by distillation under argon
before use. C5H5SiMe2Cl [13]. Mo(CO)3(NCMe)3 [14]
and W(CO)3(NCMe)3 [14] were prepared according to
reported methods.
IR spectra were recorded in Nujol mulls between CsI
pellets over the range 4000–200 cm−1 on a Perkin-
1
1
Elmer 583 spectrophotometer. H- and 13C-NMR spec-
429 m. H-NMR (C6D6): l 4.66 (m, 4H, C5H4), 0.32 (s,
6H, –SiMe2Cl), −7.33 (s, 1H, JWH=36.6 Hz, Hhydride).
13C{1H}-NMR (C6D6): l 216.3 (s, JWC=143.1 Hz,
CO), 94.2 (s, Cipso), 93.5 (s, C5H4), 92.9 (s, C5H4), 2.5
(s, –SiMe2Cl). Anal. Calc. for C10H11ClO3SiW: C,
28.14; H, 2.57. Found: C, 27.9; H, 2.00.
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 benzene-d6 and chloroform-d1 used as
solvents and coupling constants are in Hz. C, H and N
analyses were carried out with a Perkin-Elmer 240 C
microanalyzer.
4.3. [Mo(p5-C5H4SiMe2Cl)(CO)3Cl] 3
4.1. [Mo(p5-C5H4SiMe2Cl)(CO)3H] 1
CCl4 (3 ml, 31.1 mmol) was added to a CH2Cl2 (30
ml) solution of 1 (6.82 g, 20.13 mmol). The mixture was
stirred for 24 h at room temperature to give an orange
solution. The solvent was removed under vacuum and
the resulting orange oil was extracted into n-hexane (10
ml) and cooled to –40°C to give an orange solid which
was filtered and dried in vacuo to be characterized as 3
in 95% yield. IR (CsI, cm−1): 2056 s, 1985 s, 1260 s,
Chloro(cyclopentadienyl)dimethylsilane (4.22 ml,
26.7 mmol) was added to a THF (75 ml) solution of
[Mo(CO)3(CH3CN)3] (8.1 g, 26.7 mmol). The starting
yellow solution was stirred for 2 h at reflux, turning to
a brown colour. The solvent was removed completely in
vacuo and the resulting brown oil extracted into n-hex-
ane (2×10 ml) to give an orange-brown oil character-
ized as 1 (8.56 g, 94%). IR (CsI, cm−1): 2029 s, 1940 s,
1
1167 s, 1032 m, 809 s, 470 m. H-NMR (C6D6): l 4.69,
4.52 (AA% and BB% parts of an AA%BB% spin system, 4H,
C5H4), 0.41 (s, 6H, –SiMe2Cl). 13C{1H}-NMR (C6D6):
l 241.4 (s, 1C, CO), 223.9 (s, 2C, CO), 98.9 (s, Cipso),
104.8 (s, C5H4), 95.6 (s, C5H4), 2.36 (s, –SiMe2Cl).
Anal. Calc. for C10H10Cl2O3SiMo: C, 32.19; H, 2.68.
Found: C, 31.89; H, 2.90.
1
1259 s, 1040 m, 808 s, 489 m. H-NMR (C6D6): l 4.75,
4.69 (AA% and BB% parts of an AA%BB% spin system, 4H,
C5H4), 0.32 (s, 6H, –SiMe2Cl), −5.6 (s, 1H, Hhydride).
13C{1H}-NMR (C6D6): l 226,7 (s, CO), 104.7 (s, Cipso),
94.3 (s, C5H4), 94.1 (s, C5H4), 2.57 (s, –SiMe2Cl). Anal.
Calc. for C10H11ClO3SiMo: C, 35.35; H, 3.53. Found:
C, 35.16; H, 3.42.
4.4. [W(p5-C5H4SiMe2Cl)(CO)3Cl] 4
4.2. [W(p5-C5H4SiMe2Cl)(CO)3H] 2
CCl4 (3 ml) was added to a CH2Cl2 (30 ml) solution
of 2 (1.5 g, 3.25 mmol) and the mixture was stirred for
24 h at room temperature to give an orange solution.
The solvent was removed under vacuum and the re-
sulting orange oil was extracted into n-hexane (10 ml)
and cooled to −40°C. An orange crystalline solid
Chloro(cyclopentadienyl)dimethylsilane (1.25 ml, 8.0
mmol) was added to a THF (30 ml) solution of
[W(CO)3(CH3CN)3] (3.08 g, 7.8 mmol). The starting
yellow solution was refluxed for 3 h turning to a brown
Table 2
13C-NMR (C6D6)a data for complexes MCp(CO)3X (X=H, Cl)
Complex
–C5H4–
–SiMe2–
CO
MoCpCl(CO)3H (1)
WCpCl(CO)3H (2)
104.7 (Cipso), 94.3, 94.1
94.2 (Cipso), 93.5, 92.9
98.9 (Cipso), 104.8, 95.6
96.2 (Cipso), 102.7, 94.3
99.3 (Cipso), 95.0, 93.7
101.3 (Cipso), 104.6, 95.8
103.4 (Cipso), 105.3, 93.9
2.57 (s)
2.50 (s)
2.36 (s)
2.20 (s)
1.22 (s)
1.26 (s)
0.85 (s)
226.7 (s, 3C)
216.3 (s, 3C, JWC=143.1)
241.4, 223.9 (s, 1C, s, 2C)
230.7, 215.3 (s, 1C, s, 2C)
227.5 (s, 3C)
242.5, 224.7 (s, 1C, s, 2C)
242.2, 224.8 (s, 1C, s, 2C)
MoCpCl(CO)3Cl (3)
WCpCl(CO)3Cl (4)
[Mo(CO)3H]2(v-CpO) (5)
[Mo(CO)3Cl]2(v-CpO) (6)
MoCpOH(CO)3Cl (8)
a Chemical shifts are given in ppm. Coupling constants are given in Hz.

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F. Ja6ier de la Mata et al. / Journal of Organometallic Chemistry 572 (1999) 155–161
4.8. [Mo(p5-C5H4SiMe2OH)(CO)3Cl] 8
precipitated which after being filtered and dried in
vacuo was characterized as 4 (90% yield). 1H-NMR
(C6D6): l 4.66 (m, 4H), 0.41 (s, 6H, –SiMe2Cl).
13C{1H}-NMR (C6D6): l 230.7 (s, 1C, CO), 215.3 (s,
2C, CO), 96.2 (s, Cipso), 102.7 (s, C5H4), 94.3 (s, C5H4),
2.2 (s, –SiMe2Cl). Anal. Calc. for C10H10Cl2O3SiW: C,
26.04; H, 2.17. Found: C, 26.42; H, 2.22.
LiOH (0.027 g, 1.12 mmol) was added to a toluene
(25 ml) solution of 3 (0.4 g, 1.12 mmol) and the
reaction mixture was stirred in an ultrasound bath for 1
h and then 12 h at room temperature outside the bath.
After filtration, all volatile compounds are removed
under vacuum and the residue washed with n-hexane
(2×10 ml) to give a red solid identified as 8. IR (CsI,
cm−1): 3442 m, 2057 s, 1984 s, 1259 s, 1045 m, 822 s,
4.5. [{Mo(CO)3H}2(p5-C5H4-SiMe2-O-SiMe2-p5-
C5H4)] 5
1
476 m. H-NMR (C6D6): 4.81, 4.44 (AA% and BB% parts
of an AA%BB% spin system, 4H, C5H4), 3.03 (s, 1H,
–OH), 0.22 (s, 6H, –SiMe2OH). 13C{1H}-NMR
(C6D6): l 242.2 (s, 1C, CO), 224.8 (s, 2C, CO), 103.4 (s,
Cipso), 105.3 (s, C5H4), 93.9 (s, C5H4), 0.85 (s,
–SiMe2OH). Anal. Calc. for C10H11ClO4SiMo: C,
33.87; H, 3.10. Found: C, 34.48; H, 3.06.
Deoxygenated water (27 ml, 1.49 mmol) was added
by syringe to a toluene (30 ml) solution of 1 (0.5 g, 1.49
mmol) and the mixture was stirred for 16 h at room
temperature to give a red solution. The solvent was
removed under vacuum and the residue was extracted
into n-hexane (25 ml). The hexane solution was concen-
trated and stored at −40°C overnight. A solid precipi-
tated which after being filtered and dried in vacuo was
characterized as 5 (0.57 g, 50%). IR (CsI, cm−1): 2024
s, 1951 s, 1258 s, 1043 m, 823 s, 489 m. 1H-NMR
(C6D6): l 4.83, 4.79 (AA% and BB% parts of an AA%BB%
spin system, 4H, C5H4), 0.17 (s, 6H, –SiMe2O–), −
5.53 (s, 1H, Hhydride). 13C{1H} -NMR (C6D6): l 227.5
(s, CO), 99.3 (s, Cipso), 95.0 (s, C5H4), 93.7 (s, C5H4),
1.22 (s, –SiMe2O–). Anal. Calc. for C20H22O7Si2Mo2:
C, 38.57; H, 3.54. Found: C, 39.31; H, 3.69.
4.9. [Mo(p5-C5H4SiMe2Cl)Cl4] 9
A slight excess of PCl5 (8.41 g, 40.5 mmol) was
slowly added to a solution of 3 (6.85 g, 18.36 mmol) in
toluene (75 ml) and the mixture was stirred at 70°C for
12 h to give a dark red suspension. A pink precipitate
was filtered, washed with n-hexane, dried under vac-
uum and identified as 9 (6.9 g, 95%) by elemental
analysis and IR spectroscopy. IR (CsI, cm−1): 1257 s,
1051 m, 803 m, 495 m, 335 s. Anal. Calc. for
C7H10Cl5SiMo: C, 21.24; H, 2.78. Found: C, 22.04; H,
2.92.
4.6. [{Mo(CO)3Cl}2(p5-C5H4-SiMe2-O-SiMe2-p5-
C5H4)] 6
This complex can also be obtained by oxidation of 1
with PCl5, but the yield is lower.
This complex was obtained by the same procedure
described for 5 but starting from complex 3 (0.5 g, 1.34
mmol) and deoxygenated water (24 ml, 1.34 mmol), as
an orange–red solid (0.91 g, 98%). IR (CsI, cm−1):
4.10. [W(p5-C5H4SiMe2Cl)Cl4] 10
A slight excess of PCl5 (4.8 g, 23.0 mmol) was slowly
added to a solution of 2 (4.28 g, 10.0 mmol) in toluene
(50 ml) and the mixture was stirred at 70°C for 12 h,
while evolution of CO was observed. The resulting
suspension was filtered and the orange-brown solid
washed with n-hexane (2×10 ml) and dried in vacuo to
yield complex 10 (4.2 g, 85%). IR (CsI, cm−1): 1256 s,
1036 m, 802 s, 498 m, 322 s. Anal. Calc. for
C7H10Cl5SiW: C, 17.41; H, 2.07. Found: C, 18.52; H,
2.33.
1
2045 s, 1977 s, 1261 s, 1052 m, 826 s, 475 m. H-NMR
(C6D6): l 4.8, 4.76 (AA% and BB% parts of an AA%BB%
spin system, 4H, C5H4), 0.23 (s, 6H, –SiMe2O–).
13C{1H}-NMR (C6D6): l 242.5 (s, 1C, CO), 224.7 (s,
2C, CO), 101.3 (s, Cipso), 104.6 (s, C5H4), 95.8 (s,
C5H4), 1.26 (s, –SiMe2O–). Anal. Calc. for
C20H20Cl2O7Si2Mo2: C, 34.75; H, 2.89. Found: C,
34.77; H, 3.15.
4.7. [Mo(p5-C5H4SiMe2OH)(CO)3H] 7
4.11. [Mo(p5-C5H4SiMe2Cl)Cl2]2 11
LiOH (0.0021 g, 0.009 mmol) was added to a ben-
zene-d6 (0.5 ml) solution of 1 (0.03 g, 0.09 mmol) in a
NMR tube. The tube was introduced into an ultra-
sound bath for 3 h to improve the solubility of the
Fifty milliliters of a toluene solution of 9 (1.5 g, 3.79
mmol) were transferred via a canula over a 10% sodium
amalgam (0.18 g of Na, 7.58 mmol) and the reaction
mixture was stirred for 16 h. The solvent was removed
under vacuum and the resulting residue was extracted
into methylene chloride (2×30 ml). This solution was
filtered, concentrated under vacuum and cooled to
−40°C to give a yellow–green solid characterized as 11
1
LiOH. A H-NMR spectrum of the reaction mixture
recorded after this time confirmed the formation of 7.
1H-NMR (C6D6): l 4.83, 4.76 (AA% and BB% parts of an
AA%BB% spin system, 4H, C5H4), 1.15 (s, 1H, –OH),
0.11 (s, 6H, –SiMe2OH), −5.54 (s, 1H, Hhydride).

F. Ja6ier de la Mata et al. / Journal of Organometallic Chemistry 572 (1999) 155–161
161
(1.8 g, 73%). IR (CsI, cm−1): 1257 s, 1044 m, 803 m,
491 w, 328 w. H-NMR (C6D6): l 5.91, 5.67 (AA% and
Acknowledgements
1
BB% parts of an AA%BB% spin system, 4H, C5H4), 0.06 (s,
6H, –SiMe2Cl). 13C{1H}-NMR (C6D6): l 107.1 (s,
Cipso), 111.7 (s, C5H4), 108.8 (s, C5H4), 1.3 (s,
–SiMe2Cl). Anal. Calc. for C14H20Cl6Si2Mo2: C, 25.91;
H, 3.08. Found: C, 25.00; H, 3.39.
The authors acknowledge DGICYT (project PB92-
0178-C) for financial support.
References
4.12. [W(p5-C5H4SiMe2Cl) (NtBu)Cl2] 12
[1] (a) G. Wilkinson, J. Am. Chem. Soc. 76 (1954) 209. (b) E.O.
Fischer and W. Hafner, Z. Naturforsch. 10b (1955) 140. (c) E.O.
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(1955) 47.
t
A stoichiometric amount of freshly distilled BuNH2
(0.63 ml, 6.13 mmol) and two equivalents of NEt3 (1.70
ml, 12.32 mmol) were added to a toluene (50 ml)
suspension of 10 (3 g, 6.13 mmol) and the mixture was
stirred for 24 h to give a brown suspension. The
ammonium salt formed was filtered off and all volatile
compounds were removed in vacuum yielding a brown
solid. Recrystallization of the residue from n-hexane
(30 ml) gave complex 12 in 70% yield. IR (CsI, cm−1):
1322 m, 1258 s, 1026 m, 777 s, 494 m, 331 m. Anal.
Calc. for C11H19Cl3NSiW: C, 27.31; H, 3.93; N, 2.89.
Found: C, 26.72; H, 4.42; N, 2.72.
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4.13. [W(p5-C5H4SiMe2Cl) (NtBu)Cl3] 13
A toluene solution of 12 (2 g, 4.13 mmol) was treated
with PCl5 (0.43 g, 2.06 mmol). The colour of the
solution changed from brown to yellow and after stir-
ring for 12 h at room temperature the insoluble solid
was removed by filtration. The toluene solution was
cooled to −40°C to give complex 13 as a yellow
microcrystalline solid (1.9 g, 90% yield). IR (CsI,
cm−1): 1317 m, 1256 s, 1055 m, 807 s, 492 m, 329 m.
1H-NMR (C6D6): l 6.46, 5.48 (AA% and BB% parts of an
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[8] The same complex can be prepared, in similar yield, by reaction
of [1,3,5-C6H3Me3]Mo(CO)3 and C5H5SiMe2Cl in THF.
[9] (a) Ref. [4]. (b) M.D. Curtis, J.J. D’Errico, D.N. Duffy, P.S.
Epstein, L.G. Bell, Organometallics 2 (1983) 1808.
t
AA%BB% spin system, 4H, C5H4), 1.02 (s, 9H, Bu), 0.79
(s, 6H, –SiMe2Cl). 13C{1H}-NMR (C6D6): l 122.6 (s,
Cipso), 135.0 (s, C5H4), 102.9 (s, C5H4), 77.0 (s,
C(CH3)3), 28.3 (s, C(CH3)3), 1.1 (s, –SiMe2Cl). Anal.
Calc. for C11H19Cl4NSiW: C, 25.43; H, 3.66; N, 2.69.
Found: C, 25.63; H, 4.06; N, 2.59.
4.14. [Mo(p5-C5H4SiMe2Cl) (N-2,6-(Me2)-C6H3)Cl2]
14
A stoichiometric amount of freshly distilled 2,6-Me2-
C6H3NH2 (0.43 ml, 3.5 mmol) and two equivalents of
NEt3 (0.97 ml, 7.0 mmol) were added to a toluene (50
ml) suspension of 9 (1.6 g, 3.5 mmol) and the mixture
was stirred for 24 h to give a brown suspension. The
ammonium salt formed was filtered off and all volatile
compounds were removed in vacuo yielding an orange
oil. Recrystallization of the residue from n-hexane (30
ml) yielded 1.01 g (65%) of orange crystals of complex
14. IR (CsI, cm−1): 1580 w, 1376 m, 1257 s, 1041 m,
802 s, 494 m, 320 m. Anal. Calc. for C15H19Cl3NSiMo:
C, 40.59; H, 4.30; N, 3.16. Found: C, 39.77; H, 4.37; N,
2.76.
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