Synthesis of silyl-molybdenum complexes connected by a 1,1′- metallocenylene unit and their electrochemical properties

Article abstract of DOI:10.1002/ejic.201100867

Methyl-molybdenum complexes react with hydrosilanes or hydrogermane under photo-irradiation to form the corresponding silyl- or germyl-molybdenum complexes, [(η⁵-C₅Me₅)Mo(CO) ₃(ER₃)] [ER₃ = SiPh₃ (1), GePh ₃ (2), SiMe₂Ph (3), SiMe₂(C₅H ₄FeC₅H₅) (4)]. This method can be adapted to form metallocenylene compounds that bear two dimethylsilyl groups, [{(η⁵-C₅Me₅)Mo(CO)₃(SiMe ₂C₅H₄)}₂M] [M = Fe (5), Ru (6)]. All of the new complexes were fully characterized by means of ¹H and ¹³C{¹H} NMR spectroscopy and elemental analyses. In addition, the structures of 1, 5, and 6 were determined by single-crystal X-ray diffraction studies. The electrochemical measurements of the ferrocene derivatives that bear one or two {(η⁵-C₅Me ₅)Mo(CO)₃(SiMe₂)} substituent(s) revealed that the {(η⁵-C₅Me₅)Mo(CO)₃(SiMe ₂)} unit has an electron-donating nature. Demethanative Mo-Si bond formation was attained in the photoreaction of [CpMo(CO)₃(Me)] with ferrocene, which had one or two dimethylsilyl group(s). The electrochemical properties of these complexes are explained by cyclic voltammetry. Copyright

Full text of DOI:10.1002/ejic.201100867

FULL PAPER
DOI: 10.1002/ejic.201100867
Synthesis of Silyl–Molybdenum Complexes Connected by a 1,1Ј-
Metallocenylene Unit and Their Electrochemical Properties
Masumi Itazaki,[a] Akio Ichimura,[a] and Hiroshi Nakazawa*[a]
Keywords: Molybdenum / Ferrocene / Si ligands / Structure elucidation / Cyclic voltammetry
Methyl–molybdenum complexes react with hydrosilanes or
hydrogermane under photo-irradiation to form the corre-
sponding silyl– or germyl–molybdenum complexes, [(η5-
C5Me5)Mo(CO)3(ER3)] [ER3 = SiPh3 (1), GePh3 (2), SiMe2Ph
(3), SiMe2(C5H4FeC5H5) (4)]. This method can be adapted to
form metallocenylene compounds that bear two dimethylsilyl
groups, [{(η5-C5Me5)Mo(CO)3(SiMe2C5H4)}2M] [M = Fe (5),
Ru (6)]. All of the new complexes were fully characterized by
means of 1H and 13C{1H} NMR spectroscopy and elemental
analyses. In addition, the structures of 1, 5, and 6 were deter-
mined by single-crystal X-ray diffraction studies. The elec-
trochemical measurements of the ferrocene derivatives that
bear one or two {(η5-C5Me5)Mo(CO)3(SiMe2)} substituent(s)
revealed that the {(η5-C5Me5)Mo(CO)3(SiMe2)} unit has an
electron-donating nature.
Introduction
The transition metal complexes that have a silylferrocene
moiety have been investigated as an important species for a
poly(silylferrocene), which exhibits attractive conductivity,
magnetic properties, and a high thermal stability.[1] When
1,1Ј-bis(silyl)ferrocene is the silylferrocene moiety, the com-
plexes that have two M–Si bonds are divided into two
groups. One group contains an ansa-type complex in which
the two M–Si bonds have a direct interaction through one
or two metal center(s) (Figures 1a and b) and the other
group is a linear-type complex in which the two M–Si
bonds are terminal (Figure 1c). However, these examples
are limited, and the electrochemical properties of these
complexes have not been well established.[2]
(1)
This result prompted us to examine the possibility of
Mo–Si bond formation through the demethanation of an
Mo–Me complex with an H–Si compound [Equation (2)].
(2)
There are some examples in the group 6 transition metal
triads in which an M–Si bond is thought to be formed by
demethanation, but few straightforward examples of deme-
thanative M–Si bond formation have been reported.[4,5] The
demethanative reactions are appealing since both of the
starting compounds are easy to handle, and the methane
that forms as a byproduct can be readily removed. Thus,
we planned to use the demethanation reaction of a methyl–
molybdenum complex with 1,1Ј-bis(silyl)metallocene in or-
der to obtain linear-type complexes that have two terminal
Mo–Si bonds [Equation (3)]. Herein, we report the synthe-
ses of mononuclear Mo–Si(Ge) complexes and trinuclear
Figure 1. Two types of groups for the 1,1Ј-bis(silyl)ferrocenylene
complex that has two M–Si bonds.
The Shimoi group[3a] and our group[3b,3c] have previously
reported that Mo–B bond formation was achieved by the
demethanation of an Mo–Me complex with an H–B com-
pound [Equation (1)].
[a] Department of Chemistry,
Graduate School of Science Osaka City University,
3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
Fax: +81-6-6605-2522
E-mail: nakazawa@sci.osaka-cu.ac.jp
(3)
5496
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Synthesis and Electrochemical Properties of Silyl–Molybdenum Complexes
Mo–Si complexes that are connected by a 1,1Ј-metallocen-
ylene unit. We also present the electrochemical properties
of these complexes.
Results and Discussion
Scheme 2. Reaction of [Cp*Mo(CO)3(Me)] with (dimethylsilyl)fer-
rocene.
Only a few Mo–Si and Mo–Ge complexes that have a Cp
ligand (Cp = η5-C5H5) or its derivative have been previously
synthesized.[5–7] A typical method that is used to prepare
the Mo–Si complexes is the reaction of a halosilane with an
alkali metal anionic species, [M{(η5-C5R5)(CO)3Mo}] (M =
Li, Na, K; R = Me, H) [Equation (4)].[6b–6f,6j] However, this
method has some shortcomings, such as the instability of
the alkali metal anionic species and the inapplicability of
silicon compounds that have a functional group.
A limited number of monosilylferrocenes have been re-
ported where the silyl group is bonded to the transition
metal atom.[2e,10] In addition, the reactions with 1,1Ј-bis(di-
methylsilyl)metallocene, [(HMe2SiC5H4)2M] (M = Fe,[11]
Ru[2e]), afforded the trinuclear complexes 5 and 6 that have
two terminal Mo–Si bonds (Scheme 3). Although the Si
atom for 4 and 5 has two Me groups, surprisingly 4 and 5
are thermally more stable than 3, which also has two Me
substituents. The ferrocenyl and metallocenylene moieties
seem to have a strong electron-withdrawing property in
these complexes (vide infra). In the case of the metallocenes
that have one or two diphenylsilyl group(s), this method
was not applicable presumably due to the steric repulsion.
(4)
In order to overcome these shortcomings, we attempted a
demethanative reaction of an Mo–Me complex with R3SiH
(R3GeH) to form an Mo–Si(Ge) bond. The methyl–molyb-
denum complex, [Cp*Mo(CO)3(Me)] (Cp* = η5-C5Me5),[8]
was treated with an equimolar amount of Ph3EH (E = Si,
Ge) in benzene at 5 °C under photo-irradiation and pro-
duced the corresponding complexes, [Cp*Mo(CO)3(EPh3)]
[E = Si (1), Ge (2)], which contained an Mo–Si and an Mo–
Ge single bond, respectively (Scheme 1). Dimethyl(phenyl)
silane (Me2PhSiH) afforded the corresponding Mo–Si com-
plex 3 in 67% yield, whereas several complexes were formed
that could not be identified when Et3SiH and HEt2SiSi-
Et2H were used. Complex 1 was stable for several weeks in
air, but 3 decomposed within a few hours in solution even
under nitrogen. It would seem that the Mo–Si complexes
were stabilized by the electron-withdrawing substituent(s)
on the Si atom. This is consistent with the stability tendency
of [CpMo(CO)3(SiR3)] where SiCl3 Ͼ SiBr3 ≈ SiCl2H Ͼ
SiCl2Me ≈ SiClHMe Ͼ SiMe3.[6b]
Scheme 3. Reaction of [Cp*Mo(CO)3(Me)] with the metallocenes
that have one or two dimethylsilyl group(s).
A plausible pathway for the Mo–E (E = Si, Ge) bond
formation in complexes 1–6 is shown in Scheme 4. One of
the CO ligands in [Cp*Mo(CO)3(Me)] is released by photo-
irradiation to give [Cp*Mo(CO)2(Me)] (A). The oxidative
addition of an H–E bond to the 16e– Mo complex yields
Scheme 1. Synthesis of the silyl– and germyl–molybdenum com-
plexes.
Next, we examined the reactions of [Cp*Mo(CO)3(Me)]
with hydrosilanes that have a metallocene moiety as a func-
tional group. The photoreaction of [Cp*Mo(CO)3(Me)]
with (dimethylsilyl)ferrocene, [(HMe2SiC5H4)FeCp] (Cp =
η5-C5H5),[9] afforded the corresponding Mo–Si complex 4
(Scheme 2).
Scheme 4. Proposed mechanism of demethanative Mo–E (E = Si,
Ge) bond formation.
Eur. J. Inorg. Chem. 2011, 5496–5501
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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M. Itazaki, A. Ichimura, H. Nakazawa
FULL PAPER
[Cp*MoIV(CO)2(H)(Me)(ER3)] (B). The subsequent re-
ductive elimination of CH4 affords [Cp*MoII(CO)2(ER3)]
(C), and the recoordination of CO gives the final complex
[Cp*Mo(CO)3(ER3)]. The evolution of CH4 gas was con-
1
firmed by the H NMR spectrum (δ = 0.15 ppm in C6D6).
It has been reported for iron complexes[12,13] that the oxi-
dative addition of the Si–H bond to [CpFe(CO)(SiR3)]
takes place and forms [CpFe(CO)(H)(SiR3)2], which has
been isolated and characterized by X-ray analysis.[12j–12m]
Therefore, the formation of the MoIV complex B is highly
likely, although it has not been detected. An E–H agostic
interaction that is followed by a σ-bond metathesis pathway
cannot be ruled out in place of the E–H oxidative addition
(A Ǟ B) that is followed by methane reductive elimination
(B Ǟ C).
The structures of 1, 5, and 6 were determined by X-ray
crystallography. The molecular structures of 1, 5, and 6 are
shown in Figures 2 and 3. Selected bond lengths and angles
and crystal data are listed in Tables 1 and 2, respectively.
Two independent molecules of 1 crystallized in the unit cell.
The molecular structure of the Mo1 molecule of 1 is de-
picted in Figure 2 with the atomic numbering scheme. The
Mo atom has a four-legged piano-stool geometry that bears
C5Me5 in an η5-fashion, three terminal CO ligands, and an
Figure 2. ORTEP drawing of the Mo1 molecule of 1 with 50%
thermal ellipsoidal plots; hydrogen atoms were omitted for sim-
plicity.
SiPh3 ligand with an Mo–Si bond. The Mo–Si bond lengths the first example that has two terminal transition metal–
of 1 [2.6531(7), 2.6616(7) Å] resemble those of the pre- silicon bonds. In addition, 6 is the first example of a si-
viously reported complexes (2.504–2.670 Å).[5,6c,6d,6g,14] For lylated ruthenocene with metal–silicon bond(s). The Mo–
5 and 6, the two molybdenum units, [Cp*Mo(CO)3], are Si bonds of 5 [2.6807(9), 2.6660(9) Å] and 6 [2.6675(17),
connected by means of the {–(Me2SiC5H4)M(C5H4SiMe2)–} 2.6752(17) Å] are slightly longer than those of 1.
spacer [Figure 3a, M = Fe for 5 and Figure 3b, M = Ru for
The redox behavior of 1 and 4–6 was examined by cyclic
6]. Only two crystal structures that have the {–(R2SiC5H4)- voltammetry (CV). The measurements were undertaken in
Fe(C5H4SiR2)–} spacer with two M–Si (M = metal) bonds a 0.10 m nBu4NPF6/CH2Cl2 solution at a scan rate of
have been reported previously (Figure 4).[2a,2c] Complex 5 is 0.1 Vs–1 at room temperature. Complex 1 showed irrevers-
Figure 3. ORTEP drawings of 5 (a) and 6 (b) with 50% thermal ellipsoidal plots; hydrogen atoms were omitted for simplicity.
5498
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Eur. J. Inorg. Chem. 2011, 5496–5501

Synthesis and Electrochemical Properties of Silyl–Molybdenum Complexes
Table 1. Selected bond lengths [Å] and bond angles [°] for 1, 5, and
6.
1
5
6
Bond lengths
Mo1–Si1
Mo1–C11
Mo1–C12
Mo1–C13
2.6531(7) 2.6803(8)
2.6675(17)
1.975(7)
1.965(7)
1.958(7)
2.6752(17)
1.968(7)
1.964(6)
1.968(6)
1.980(2)
1.968(3)
1.978(3)
1.985(3)
1.976(3)
1.972(3)
Mo2–Si2
2.6616(7) 2.6658(8)
Mo2–C38 (C42 for 1)
Mo2–C39 (C43 for 1)
Mo2–C40 (C44 for 1)
1.979(3)
1.987(3)
1.962(3)
1.967(3)
1.968(3)
1.989(3)
Bond angles
Si1–Mo1–C12
Mo1–Si1–C14
123.35(7) 126.58(9)
113.30(9)
123.5(2)
112.62(17)
Si2–Mo2–C39 (C44 for 1) 116.38(8) 122.80(10) 126.43(17)
Mo2–Si2–C19 112.73(9) 113.82(18)
Figure 5. Cyclic voltammograms of (a) 0.5 mm of 4 at 25 °C and (b)
0.5 mm of 5 at 25 °C in a CH2Cl2 solution that contains nBu4NPF6
(0.10 m) (scan rate = 0.1 Vs–1); E1/2 = 0.18 V for 4 and 0.12 V for
5.
fore, the {Cp*Mo(CO)3(SiMe2)} moiety can be considered
to be an electron-donating group. In 2008 Pannell et al.
reported that the E1/2 value of ferrocene with the
{CpFe(CO)2(SiMe2)} moiety was higher than that of ferro-
cene. These results show that the {CpFe(CO)2(SiMe2)} moi-
ety has an electron-withdrawing nature.[10a] The difference
between the electrochemical nature of the {Cp*Mo-
(CO)3(SiMe2)} and {CpFe(CO)2(SiMe2)} moieties probably
stems from the stronger electron-donating ability of the
pentamethylcyclopentadienyl group (Cp*) than that of the
cyclopentadienyl group (Cp). It has been reported that the
CV of ruthenocene shows an irreversible one-step two-elec-
tron oxidation process.[17] Complex 6, which has a rutheno-
cene unit, showed the same CV behavior.
Figure 4. Two types of 1,1Ј-bis(silyl)ferrocene complexes with
metal–silicon bonds that were previously reported.
ible redox behavior, which indicated that the Mo–Si bond
is susceptible to redox reactions. In contrast, 4 and 5 under-
went reversible one-electron oxidation. The cyclic voltam-
mograms are illustrated in Figure 5 and correspond to sin-
gle reversible ferrocene/ferrocenium redox behavior. Extrac-
tion of some of the effects of the two silyl substituents
[–SiMe2H and –(SiMe2)(CO)3MoCp*] on the ferrocene/
ferrocenium redox behavior was attempted from the CV
measurements (Figure 6). The E1/2 value for 1,1Ј-bis(dime-
thylsilyl)ferrocene (0.30 V vs. Ag/Ag+)[15] is higher than that
for (dimethylsilyl)ferrocene (0.27 V), which in turn is higher
than that of ferrocene (0.23 V). Therefore, a dimethylsilyl
group on ferrocene can be considered to have an electron-
withdrawing nature. This tendency is consistent with that
Conclusions
A convenient demethanative Mo–Si or Mo–Ge bond for-
reported by Okuda.[16] The E1/2 value of 0.18 V for 4 is mation from an Mo–Me complex and an H–Si or H–Ge
higher than the E1/2 value of 0.12 V for 5. The introduction compound has been reported. The electrochemical investi-
of the [Cp*Mo(CO)3SiMe2] group into the ferrocene Cp gations with cyclic voltammetry revealed that the HSiMe2
ring(s) causes the E1/2 value to be lower cumulatively group is electron-withdrawing and that the [Cp*Mo-
(0.23 V for ferrocene Ǟ 0.18 V for 4 Ǟ 0.12 V for 5). There- (CO)3(SiMe2)] group is electron-donating.
Figure 6. Redox potentials of ferrocene and the derivatives with one or two HSiMe2 or {Cp*Mo(CO)3(SiMe2)} substituent(s); [Mo] =
[Cp*Mo(CO)3(SiMe2)].
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M. Itazaki, A. Ichimura, H. Nakazawa
FULL PAPER
(1.00 mmol, 305 mg) gave 2 (0.89 mmol, 550 mg, 89%) as an
orange powder. 1H NMR (400 MHz, C6D6): δ = 1.54 (s, 15 H, Me),
7.14–7.22 (m, 9 H, Ph), 7.77 (d, JH,H = 6.8 Hz, 6 H, Ph) ppm.
13C{1H} NMR (100.4 MHz, C6D6): δ = 11.02 (CMe), 104.69
(CMe), 128.08 (Ph), 128.34 (Ph), 135.89 (Ph), 143.85 (Ph-ipso),
229.57 (CO), 235.70 (CO) ppm. C31H30GeMoO3 (619.11): calcd. C
60.14, H 4.88; found C 59.88, H 5.05.
Experimental Section
General Methods: All of the manipulations were carried out by
using standard Schlenk techniques under nitrogen. The methyl-
molybdenum complex [Cp*Mo(CO)3(Me)],[8] (dimethylsilyl)-
ferrocene,[9] 1,1Ј-bis(dimethylsilyl)ferrocene,[11] and 1,1Ј-bis(di-
methylsilyl)ruthenocene[2e] were prepared according to literature
methods. The other chemicals were purchased. All of the solvents
were distilled from the appropriate drying agents (sodium and
benzophenone for hexane and benzene, P2O5 for CH2Cl2, and
CaH2 for MeCN) under dry nitrogen prior to use. NMR spectra
(1H and 13C{1H}) were recorded with a JEOL JNM-AL 400 spec-
[Cp*Mo(CO)3(SiMe2Ph)] (3): In a procedure analogous to that
outlined above, [Cp*Mo(CO)3(Me)] (1.00 mmol, 330 mg) and
PhMe2SiH (1.00 mmol, 150 μL) gave 3 (0.67 mmol, 303 mg, 67%)
as an orange powder. 1H NMR (400 MHz, C6D6): δ = 0.89 (s, 6
H, SiMe), 1.53 (s, 15 H, CMe), 7.18 (d, JH,H = 7.6 Hz, 1 H, Ph-p),
7.25 (m, 2 H, Ph-m), 7.88 (m, 2 H, Ph-o) ppm. 13C{1H} NMR
(100.4 MHz, C6D6): δ = 4.95 (SiMe), 10.93 (CMe), 104.29 (CMe),
127.76 (Ph), 128.61 (Ph), 134.47 (Ph), 144.45 (Ph-ipso), 235.71
(CO), 239.02 (CO) ppm. C21H26MoO3Si (450.46): calcd. C 55.99,
H 5.82; found C 54.84, H 5.70.
1
trometer. The H and 13C{1H} NMR spectroscopic data are refer-
enced to the residual peaks of the solvent as an internal standard.
The photo-irradiation was performed with a 400 W medium-pres-
sure mercury arc lamp at 5 °C. Cyclic voltammetric measurements
were performed with an ALS-612A electrochemical analyzer by
using a glassy carbon working electrode, a Pt counter electrode,
and an Ag/AgPF6 reference electrode in CH2Cl2 that contained
0.1 m nBu4NPF6 (MeCN) as the supporting electrolyte at a scan
rate of 100 mVs–1. The Fc/Fc+ couple was used as an internal stan-
dard.
[Cp*Mo(CO)3(SiMe2Fc)] (Fc = C5H4FeC5H5) (4): In a procedure
analogous to that outlined above, [Cp*Mo(CO)3(Me)] (1.05 mmol,
350 mg) and HSiMe2Fc (0.92 mmol, 224 mg) gave 4 (0.54 mmol,
1
303 mg, 59%) as a yellow powder. H NMR (400 MHz, C6D6): δ
= 0.97 (s, 6 H, SiMe), 1.55 (s, 15 H, CMe), 4.10 (s, 5 H, C5H5),
4.20 (d, JH,H = 2.0 Hz, 2 H, C5H4Si), 4.39 (d, JH,H = 2.0 Hz, 2 H,
C5H4Si) ppm. 13C{1H} NMR (100.4 MHz, C6D6): δ = 5.19 (SiMe),
10.86 (CMe), 68.86 (C5H5), 70.61 (C5H4Si), 73.73 (C5H4Si), 79.57
(C5H4Si-ipso), 104.23 (CMe), 229.86 (CO), 234.46 (CO) ppm.
C25H30FeMoO3Si (558.38): calcd. C 53.78, H 5.42; found C 53.87,
H 5.45.
[Cp*Mo(CO)3(SiPh3)] (1):
A
benzene solution (8 mL) of
[Cp*Mo(CO)3(Me)] (1.00 mmol, 330 mg) and Ph3SiH (1.00 mmol,
260 mg) was subjected to photo-irradiation at 5 °C for 2 h.
The volatile materials were removed under reduced pressure and
yielded an orange solid, which was washed with hexane at –70 °C,
collected by filtration, and dried in vacuo to give 1 (0.87 mmol,
500 mg, 87%) as an orange powder. Yellow crystals of 1 that were
suitable for an X-ray diffraction study were obtained by cooling a
CH2Cl2/hexane solution to –20 °C for a few days. 1H NMR
(400 MHz, C6D6): δ = 1.52 (s, 15 H, Me), 7.16–7.22 (m, 9 H, Ph),
7.79 (d, JH,H = 6.8 Hz, 6 H, Ph) ppm. 13C{1H} NMR (100.4 MHz,
C6D6): δ = 10.79 (CMe), 104.76 (CMe), 127.77 (Ph), 128.77 (Ph),
136.70 (Ph), 141.46 (Ph-ipso), 229.88 (CO), 236.09 (CO) ppm.
C31H30MoO3Si (574.60): calcd. C 64.80, H 5.26; found C 64.67, H
5.35.
[Cp*Mo(CO)3(SiMe2FcЈMe2Si)(CO)3MoCp*] (FcЈ = C5H4FeC5H4)
(5): In a procedure analogous to that outlined above, [Cp*Mo-
(CO)3(Me)] (1.05 mmol, 350 mg) and HSiMe2FcЈMe2SiH
(0.50 mmol, 224 mg) gave 5 (0.29 mmol, 226 mg, 57%) as a yellow
powder. Yellow crystals of complex 5 that were suitable for an X-
ray diffraction study were obtained by cooling a CH2Cl2/hexane
solution to –20 °C for a few days. 1H NMR (400 MHz, C6D6): δ =
1.03 (s, 12 H, SiMe), 1.55 (s, 30 H, CMe), 4.42 (app. t, JH,H
=
[Cp*Mo(CO)3(GePh3)] (2): In a procedure analogous to that out-
lined above, [Cp*Mo(CO)3(Me)] (1.00 mmol, 330 mg) and Ph3GeH
1.6 Hz, 4 H, C5H4Si), 4.52 (app. t, JH,H = 1.6 Hz, 4 H, C5H4Si)
ppm. 13C{1H} NMR (100.4 MHz, C6D6): δ = 5.41 (SiMe), 10.97
Table 2. Crystallographic data and structural refinement details for 1, 5, and 6.
1
5
6
Empirical formula
Formula mass
C31H30MoO3Si
574.58
C40H50FeMo2O6Si2
930.71
C40H50Mo2O6RuSi2
975.93
T [K]
Crystal system
Space group
120(2)
120(1)
monoclinic
P21/c
200(2)
monoclinic
P21/c
triclinic
¯
P1
a [Å]
b [Å]
c [Å]
α [°]
β [°]
γ [°]
8.9900(3)
16.2800(6)
18.6800(8)
83.990(3)
89.930(5)
84.510(5)
2706.35(18)
4
16.7453(8)
15.7729(6)
16.4598(7)
16.851(5)
15.842(4)
16.627(5)
111.023(2)
110.158(3)
Unit cell volume [Å3]
Number of formula units per unit cell, Z
ρcalcd. [mgm–3]
μ [mm–1]
4058.0(3)
4
1.523
4167(2)
4
1.556
1.410
0.559
1.064
1.051
F(000)
1184
0.30ϫ0.20ϫ0.10
19755
11298 (0.0168)
0.0347
1904
0.26ϫ0.24ϫ0.16
29469
8746 (0.0197)
0.0316
1976
0.20ϫ0.10ϫ0.02
33456
9490 (0.0611)
0.0718
Crystal size [mm]
Reflections collected
R(int)
R1 [IϾ2σ(I)]
wR2 [IϾ2σ(I)]
Goodness of fit
0.0952
1.178
0.1100
1.183
0.1241
1.186
5500
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Eur. J. Inorg. Chem. 2011, 5496–5501

Synthesis and Electrochemical Properties of Silyl–Molybdenum Complexes
aba, M. Tsukamoto, T. Hirata, C. Kabuto, H. Horino, J. Am.
Chem. Soc. 2000, 122, 11511–11512.
a) M. Hirotsu, T. Nunokawa, K. Ueno, Organometallics 2006,
25, 1554–1556; b) K. Ueno, A. Masuko, H. Ogino, Organome-
tallics 1999, 18, 2694–2699.
(CMe), 71.76 (C5H4Si), 73.98 (C5H4Si), 79.69 (C5H4Si-ipso), 104.27
(CMe), 229.83 (CO), 234.20 (CO) ppm. C40H50FeMo2O6Si2
(930.73): calcd. C 51.62, H 5.41; found C 51.88, H 5.41.
[5]
[Cp*Mo(CO)3(SiMe2RcЈMe2Si)(CO)3MoCp*] (RcЈ
= C5H4Ru-
C5H4) (6): In a procedure analogous to that outlined above,
[Cp*(CO)3Mo(Me)] (1.28 mmol, 423 mg) and HSiMe2RcЈMe2SiH
(0.64 mmol, 221 mg) gave 6 (0.26 mmol, 260 mg, 42%) as a pale
orange powder. Colorless crystals of complex 6 that were suitable
for an X-ray diffraction study were obtained by cooling a CH2Cl2/
hexane solution to –60 °C for a few days. 1H NMR (400 MHz,
C6D6): δ = 0.86 (s, 12 H, SiMe), 1.62 (s, 30 H, CMe), 4.73 (app. t,
JH,H = 1.6 Hz, 4 H, C5H4Si), 4.92 (app. t, JH,H = 1.6 Hz, 4 H,
C5H4Si) ppm. 13C{1H} NMR (100.4 MHz, C6D6): δ = 5.73 (SiMe),
10.75 (CMe), 73.50 (br., C5H4Si), 75.95 (br., C5H4Si), 84.02
(C5H4Si-ipso), 104.23 (CMe), 230.03 (CO), 234.36 (CO) ppm.
C40H50Mo2O6RuSi2 (975.95): calcd. C 49.23, H 5.16; found C
49.02, H 5.22.
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Crystal Structure Determination: Crystals of 1, 5, and 6 that were
suitable for X-ray diffraction studies were separately mounted in a
glass capillary. The data were collected at 120 K for 1 and 5 and
at 200 K for 6 with a Rigaku AFC-7/Mercury CCD area-detector
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Acknowledgments
This work was supported by a Challenging Explorating Research
(No. 23655056) and by a Grant-in-Aid for Young Scientists (B)
(No. 23750063) from the Ministry of Education, Culture, Sports,
Science and Technology, Japan.
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Received: August 19, 2011
Published Online: November 8, 2011
Eur. J. Inorg. Chem. 2011, 5496–5501
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
5501