A new approach to directly synthesize (η5-C 5H4R)Fe(CO)2SiR′3 by reaction of cyclopentadienes with pentacarbonyliron and hydrosilanes

Article abstract of DOI:10.1021/om500066y

A new approach to the direct synthesis of Fe-Si-bonded complexes (η⁵-C₅H₄R)Fe(CO)₂SiR′ ₃ (1) by the reaction of cyclopentadienes C₅H₅R (2) with pentacarbonyliron in the presence of hydrosilanes R′ ₃SiH (5) has been developed. Thus, when the reaction of 2 and pentacarbonyliron in refluxing p-xylene was performed in the presence of 5, the desired complexes were successfully obtained in good yields, providing a simple one-step synthetic route to obtain 1 from the readily available starting materials, wherein the substituents R and R′ could vary over a wide range: C₅H₅R = C₅H₅SiMe ₂SiMe₃, R′₃ = Ph₃ (1a); C ₅H₅R = C₅H₅SiMe₂SiMe ₂Ph, R′₃ = Ph₃ (1b); C₅H ₅R = C₅H₅SiMe₂SiMePh₂, R′₃ = Ph₃ (1c); C₅H₅R = C ₅H₅SiMe₂SiPh₃, R′₃ = Ph₃ (1d); C₅H₅R = C₅H ₅SiPh₂SiPh₃, R′₃ = Ph ₃ (1e); C₅H₅R = C₅H ₅SiMe₃, R′₃ = Ph₃ (1f); C ₅H₅R = C₅H₆, R′₃ = Ph₃ (1g); C₅H₅R = C₅H₅Me, R′₃ = Ph₃ (1h); C₅H₅R = C₅H₅CH₂Ph, R′₃ = Ph ₃ (1i); C₅H₅R = MeC₅H ₄SiMe₃, R′₃ = Ph₃ (1j); C ₅H₅R=C₉H₈, R′₃ = Ph₃ (1k); C₅H₅R = C₅H ₅SiMe₂SiMe₂Ph, R′₃ = Me ₂Ph (1l); C₅H₅R = C₅H ₅SiMe₂Ph₃, R′₃ = Me ₂Ph (1m); C₅H₅R = C₅H ₅SiPh₂SiPh₃, R′₃ = Me ₂Ph (1n); C₅H₅R = C₅H ₅CH₂Ph, R′₃ = Me₂Ph (1o). A plausible mechanism involving interception of coordinatively unsaturated iron species (η⁴-C₅H₅R)Fe(CO)₂ by oxidative addition of the Si-H bond is believed to be responsible for the preferred formation of the desired product.

Full text of DOI:10.1021/om500066y

Article
pubs.acs.org/Organometallics
A New Approach to Directly Synthesize (η5‑C5H4R)Fe(CO)2SiR′3 by
Reaction of Cyclopentadienes with Pentacarbonyliron and
Hydrosilanes
Guangna Gu, Haiou Luo, and Huailin Sun*
Department of Chemistry and the Collaborative Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin
300071, People’s Republic of China
S
* Supporting Information
ABSTRACT: A new approach to the direct synthesis of Fe−Si-bonded
complexes (η5-C5H4R)Fe(CO)2SiR′3 (1) by the reaction of cyclo-
pentadienes C5H5R (2) with pentacarbonyliron in the presence of
hydrosilanes R′3SiH (5) has been developed. Thus, when the reaction of 2
and pentacarbonyliron in refluxing p-xylene was performed in the presence of 5, the desired complexes were successfully
obtained in good yields, providing a simple one-step synthetic route to obtain 1 from the readily available starting materials,
wherein the substituents R and R′ could vary over a wide range: C5H5R = C5H5SiMe2SiMe3, R′3 = Ph3 (1a); C5H5R =
C5H5SiMe2SiMe2Ph, R′3 = Ph3 (1b); C5H5R = C5H5SiMe2SiMePh2, R′3 = Ph3 (1c); C5H5R = C5H5SiMe2SiPh3, R′3 = Ph3 (1d);
C5H5R = C5H5SiPh2SiPh3, R′3 = Ph3 (1e); C5H5R = C5H5SiMe3, R′3 = Ph3 (1f); C5H5R = C5H6, R′3 = Ph3 (1g); C5H5R =
C5H5Me, R′3 = Ph3 (1h); C5H5R = C5H5CH2Ph, R′3 = Ph3 (1i); C5H5R = MeC5H4SiMe3, R′3 = Ph3 (1j); C5H5R=C9H8, R′3 =
Ph3 (1k); C5H5R = C5H5SiMe2SiMe2Ph, R′3 = Me2Ph (1l); C5H5R = C5H5SiMe2Ph3, R′3 = Me2Ph (1m); C5H5R =
C5H5SiPh2SiPh3, R′3 = Me2Ph (1n); C5H5R = C5H5CH2Ph, R′3 = Me2Ph (1o). A plausible mechanism involving interception of
coordinatively unsaturated iron species (η4-C5H5R)Fe(CO)2 by oxidative addition of the Si−H bond is believed to be
responsible for the preferred formation of the desired product.
Scheme 1
INTRODUCTION
■
Transition-metal silyl complexes have attracted much interest,
not only because they act as the key intermediates in catalytic
hydrosilylation,1 dehydrogenative coupling,2 and bis-silylation3
reactions but also due to the fact that they exhibit interesting
new chemistry and intriguing properties.4 Among the large
number of complexes that have been reported,5 the family of
Fe−Si-bonded complexes (η5-C5H4R)Fe(CO)2SiR′3 (1) are
perhaps the most developed, and the salt elimination reaction,
first developed by Wilkinson and co-workers in 1956, has been
frequently used for synthesis of such complexes.6−8 This
synthesis starts from the reaction of cyclopentadienes (2) and
pentacarbonyliron to produce the iron dimers [(η5-C5H4R)Fe-
(CO)2]2 (3), which react in turn with Na/Hg to give the iron
anions (η5-C5H4R)Fe(CO)2Na (4); the latter then react with
chlorosilanes R′3SiCl to provide the final products accompanied
by elimination of sodium chloride (Scheme 1). This three-step
synthesis was later simplified by using hydrosilanes 5 as starting
materials to react with iron dimers 3, which allows the desired
complexes 1 to be obtained in only two steps.9 However, this
two-step method has been successful in just a few cases due to
the difficulty of the reaction, which requires rather severe
reaction conditions. Here, we describe a new and the most
straightforward synthetic approach to the Fe−Si-bonded
complexes via the direct reaction of cyclopentadienes and
pentacarbonyliron in the presence of hydrosilanes, which allows
for the preparation of a wide variety of the target complexes in
one step, as illustrated in Scheme 1.
RESULTS AND DISCUSSION
Synthesis of Complexes. During the course of our study
■
on the activation of Si−Si bonds in the system of the iron dimer
[(η5-C5H4SiMe2SiMe3)Fe(CO)2]2, which was normally pre-
pared by the reaction of pentamethyldisilanyl-substituted
cyclopentadiene 2a with pentacarbonyliron, we attempted to
add triphenylsilane to the reaction system, aiming to trap
coordinatively unsaturated iron species possibly formed in a
Si−Si bond activation process. The reaction of 2a with
pentacarbonyliron and triphenylsilane was performed in p-
xylene at refluxing temperature. To our surprise, the sole
Received: January 21, 2014
Published: April 2, 2014
© 2014 American Chemical Society
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product obtained was the unexpected Fe−Si-bonded complex
(η5-C5H4SiMe2SiMe3)Fe(CO)2SiPh3 (1a) (eq 1). A series of
Figure 1. Molecular structure of 1e. Hydrogen atoms are omitted for
clarity in the ORTEP plot (ellipsoids are given at the 30% probability
level). Selected bond lengths (Å) and angles (deg): Fe(1)−Si(1),
2.3395(9); Fe(1)−C(21), 2.138(2); Fe(1)−C(22), 2.111(2); Fe(1)−
C(23), 2.092(2); Fe(1)−C(24), 2.102(2); Fe(1)−C(25), 2.100(2);
C(1)−Fe(1)−Si(1), 88.37(8); C(2)−Fe(1)−Si(1), 84.98(8); C(1)−
Fe(1)−C(2), 96.14(11).
other disilanyl-substituted cyclopentadiene ligands 2b−e were
applied to the reaction under the above conditions, and the
same kind of products 1b−e were also obtained.
These successes encouraged us to use a variety of other
cyclopentadiene ligands in the reaction. When silyl-substituted
cyclopentadiene (2f), unsubstituted cyclopentadiene (2g),
alkyl-substituted cyclopentadienes (2h,i), disubstituted cyclo-
pentadiene (2j), and even indene (2k) were utilized, to our
delight, the desired respective products 1f−k were all obtained
(eq 1).
To further evaluate the scope of the reaction, phenyl-
dimethylsilane was employed to replace triphenylsilane. It is
found that this hydrosilane reacted readily with substituted
cyclopentadienes 2b,d,e,i to provide the desired products 1l−o,
respectively (eq 2).
Figure 2. Molecular structure of 1h. Hydrogen atoms are omitted for
clarity in the ORTEP plot (ellipsoids are given at the 30% probability
level). Selected bond lengths (Å) and angles (deg): Fe(1)−Si(1),
2.3311(12); Fe(1)−C(3), 2.0919(17); Fe(1)−C(4), 2.0951(17);
Fe(1)−C(5), 2.0838(18); Fe(1)−C(6), 2.0987(18); Fe(1)−C(7),
2.1216(17); C(1)−Fe(1)−Si(1), 88.13(6); C(2)−Fe(1)−Si(1),
85.56(6); C(1)−Fe(1)−C(2), 96.98(7).
All of the products were obtained in good yields in
comparison to the classical pathways9,10 and were fully
characterized by spectroscopic methods and elemental analyses.
More direct evidence for the molecular structures was achieved
by X-ray diffraction studies of 1e,h,l (Figures 1−3,
respectively). All of them demonstrate the Fe−Si-bonded
structures. The Fe−Si bond lengths are 2.3395(9) Å for 1e,
2.3311(12) Å for 1h, and 2.3401(16) Å for 1l, which are nearly
identical with each other as well as with the length of the Fe−Si
bond in (η5-C5H5)Fe(CO)2SiMePh2 (2.3353(5) Å).11 This
indicates that there should be no obvious steric hindrance
between iron and the silyl groups in all of the complexes, due
probably to the relatively long distances of the Fe−Si bonds.
Proposed Mechanisms. The mechanism of the reaction
could be rationalized as shown in Scheme 2. First, dissociation
of a CO ligand from (η4-cyclopentadiene)tricarbonyliron (6),
which is formed from the reaction of cyclopentadienes and
pentacarbonyliron, produces the coordinatively unsaturated
(η4-cyclopentadiene)dicarbonyliron (7). The Si−H bond then
quickly adds to the coordinatively unsaturated iron center,
resulting in the adduct 8. There would be two possible
pathways to continue the reaction, η4−η2 slippage of the
cyclopentadiene ligand or dissociation of a CO ligand, to afford
9 and 10, respectively, with vacant coordination sites. They
would both be able to activate the C−H bond at the
cyclopentadiene ring, followed by reductive elimination of H2,
to afford the final product.
The key step in the success of the reaction might be quick
oxidative addition of the Si−H bond to 7, which should be
much faster than activation of the C−H bond of cyclo-
pentadiene. Facile oxidative addition of a Si−H bond to similar
unsaturated iron centers has been mentioned for CpFe(CO)2R
systems,12 which could easily occur in refluxing benzene. In
contrast, activation of the C−H bond at cyclopentadiene rings
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the form of dimers as purchased. Other chemicals were purchased and
used without further purification.
Synthesis of Cyclopentadiene Ligands 2b−e,j.
C5H5SiMe2SiMe2Ph (2b), C5H5SiMe2SiMePh2 (2c), C5H5SiMe2SiPh3
(2d), and C5H5SiPh2SiPh3 (2e) were prepared following procedures
similar to those used for the synthesis of 2a in the literature,10c as
mentioned above. MeC5H4SiMe3 (2j) was prepared following
procedures similar to those used for the synthesis of 2f in the
literature.16 In addition, the crude products also were used directly in
the subsequent reactions without further characterization.
Synthesis of (η5-C5H4SiMe2SiMe3)Fe(CO)2SiPh3 (1a). In a 100
mL flask were placed 2a (1.31 g, 6.7 mmol), pentacarbonyliron (2.62
g, 13.4 mmol), triphenylsilane (2.63 g, 10.1 mmol), and 20 mL of p-
xylene. The mixture was refluxed for 24 h with magnetic stirring. After
the mixture was cooled to room temperature, the solvent was removed
under reduced pressure (unreacted Fe(CO)5, which is poisonous,
should be collected with a liquid nitrogen trap!). Then the residue was
dissolved in dichloromethane, and the resulting solution was filtered
through Celite to remove insoluble impurities. After removed of the
dichloromethane under reduced pressure, the residue was dissolved in
a small amount of dichloromethane once again and separated through
a column of neutral alumina using hexane as eluent to give 1a as a
yellow solid (0.94 g, 25% yield): mp 126−127 °C. IR (KBr): νCO 1942
(s), 1988 (s) cm−1. 1H NMR (CDCl3): δ 0.15 (s, 9H, SiCH3), 0.40 (s,
6H, SiCH3), 4.43 (s, 2H, C5H4), 4.73 (s, 2H, C5H4), 7.37 (m, 9H,
C6H5), 7.60 (m, 6H, C6H5). 13C NMR (CDCl3): δ −3.11, −2.19
(SiCH3), 88.58, 89.65, 92.57 (C5H4), 127.59, 128.24, 135.60, 142.70
(C6H5), 215.95 (CO). Anal. Calcd for C30H34FeO2Si3: C, 63.58; H,
6.05. Found: C, 63.35; H, 5.93.
Figure 3. Molecular structure of 1l. Hydrogen atoms are omitted for
clarity in the ORTEP plot (ellipsoids are given at the 30% probability
level). Selected bond lengths (Å) and angles (deg): Fe(1)−Si(1),
2.3401(16); Fe(1)−C(11), 2.103(5); Fe(1)−C(12), 2.104(4);
Fe(1)−C(13), 2.092(5); Fe(1)−C(14), 2.106(5); Fe(1)−C(15),
2.134(4); C(1)−Fe(1)−Si(1), 86.48(17); C(2)−Fe(1)−Si(1),
83.77(16); C(1)−Fe(1)−C(2), 95.3(2).
has been reported to need much higher temperatures13 or
ultraviolet irradiation.14 The iron hydride 13 thus formed has
been well documented to quickly dimerize at room temper-
ature, leading to the formation of the iron dimer 3.14a,15
Experimental results demonstrate that 3 does not react with
hydrosilanes in refluxing p-xylene. Therefore, the formation of
the final product from 3 could be ruled out under the present
reaction conditions.
Synthesis of (η5-C5H4SiMe2SiMe2Ph)Fe(CO)2SiPh3 (1b). Com-
pound 1b was synthesized by using the same procedure as described
for the preparation of 1a, starting from 2b (2.58 g, 10.0 mmol),
pentacarbonyliron (3.92 g, 20.0 mmol), and triphenylsilane (3.91 g,
15.0 mmol). The product was obtained as a yellow solid (1.38 g, 22%
CONCLUSION
■
1
yield): mp 117−119 °C. IR (KBr): νCO 1930 (s), 1988 (s) cm−1. H
A new reaction of cyclopentadienes with pentacarbonyliron and
hydrosilanes under thermal conditions has been described,
which provides a one-step and general approach to synthesize
the title Fe−Si-bonded complexes. Obviously, this method is
advantageous over all traditional syntheses. Further work will
focus on the application of this reaction to synthesize more
complex molecules containing Fe−Si bonds.
NMR (CDCl3): δ 0.37 (s, 6H, SiCH3), 0.41 (s, 6H, SiCH3), 4.34 (s,
2H, C5H4), 4.56 (s, 2H, C5H4), 7.50 (m, 20H, C6H5). 13C NMR
(CDCl3): δ −3.98, −3.01 (SiCH3), 85.00, 88.58, 89.81 (C5H4),
127.59, 127.64, 128.02, 128.25, 128.30, 128.88, 133.94, 135.59, 142.68
(C6H5), 215.89 (CO). Anal. Calcd for C35H36FeO2Si3: C, 66.86; H,
5.77. Found: C, 66.59; H, 5.85.
Synthesis of (η5-C5H4SiMe2SiMePh2)Fe(CO)2SiPh3 (1c). Com-
pound 1c was synthesized by using the same procedure as described
for the preparation of 1a, starting from 2c (2.56 g, 8.0 mmol),
pentacarbonyliron (3.13 g, 16.0 mmol), and triphenylsilane (3.12 g,
12.0 mmol). The product was obtained as a yellow solid (1.21 g, 22%
EXPERIMENTAL SECTION
■
General Procedures. All reactions were carried out under an
argon atmosphere using a vacuum line and Schlenk techniques. NMR
spectra were recorded at 400 MHz (1H) and 100 MHz (13C) using
CDCl3 as the solvent. Chemical shifts are given in terms of ppm.
Elemental analyses were performed by using a Vario EL instrument. IR
spectra were recorded with an FT-IR spectrometer. p-Xylene was
distilled from sodium/benzophenone. C5H5SiMe2SiMe3 (2a),10c
C5H5SiMe3 (2f),16 and C5H5CH2Ph (2i)17 were prepared according
to the literature methods. C5H6 (2g) and C5H5Me (2h) were used in
1
yield): mp 114−117 °C. IR (KBr): νCO 1934 (s), 1988 (s) cm−1. H
NMR (CDCl3): δ 0.44 (s, 6H, SiCH3), 0.62 (s, 3H, SiCH3), 4.27 (s,
2H, C5H4), 4.51 (s, 2H, C5H4), 7.30 (m, 25H, C6H5). 13C NMR
(CDCl3): δ −4.84, −2.43 (SiCH3), 88.66, 90.15, 91.21 (C5H4),
127.59, 127.83, 128.13, 128.26, 129.26, 129.93, 134.97, 135.31, 135.57,
136.09, 142.59 (C6H5), 215.83 (CO). Anal. Calcd for C40H38FeO2Si3:
C, 69.54; H 5.54. Found: C, 69.82; H, 5.78.
Scheme 2
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Synthesis of (η5-C5H4SiMe2SiPh3)Fe(CO)2SiPh3 (1d). Com-
pound 1d was synthesized by using the same procedure as described
for the preparation of 1a, starting from 2d (2.67 g, 7.0 mmol),
pentacarbonyliron (2.74 g, 14.0 mmol), and triphenylsilane (2.73 g,
10.5 mmol). The product was obtained as a yellow solid (1.26 g, 24%
12.0 mmol). The product was obtained as a yellow solid (0.92 g, 22%
1
yield): mp 102−104 °C. IR (KBr): νCO 1922 (s), 1984 (s) cm−1. H
NMR (CDCl3): δ 0.24 (s, 9H, SiCH3), 1.39 (s, 3H, CH3), 3.98 (s, 1H,
C5H3), 4.54 (s, 1H, C5H3), 4.82 (s, 1H, C5H3), 7.31 (m, 9H, C6H5),
7.62 (m, 6H, C6H5). 13C NMR (CDCl3): δ −0.61 (SiCH3), 11.95
(CH3), 86.42, 89.26, 91.88, 94.27, 102.88 (C5H3), 127.51, 128.15,
135.74, 142.76 (C6H5), 216.60 (CO). Anal. Calcd for C29H30FeO2Si2:
C, 66.65; H, 5.79. Found: C, 66.61; H, 5.70.
1
yield): mp 153−154 °C. IR (KBr): νCO 1938 (s), 1988 (s) cm−1. H
NMR (CDCl3): δ 0.53 (s, 6H, SiCH3), 4.23 (s, 2H, C5H4), 4.49 (s,
2H, C5H4), 7.41 (m, 30H, C6H5). 13C NMR (CDCl3): δ −1.77
(SiCH3), 88.51, 90.35, 90.84 (C5H4), 127.40, 128.04, 129.33, 134.17,
135.37, 135.87, 142.39 (C6H5), 215.63 (CO). Anal. Calcd for
C45H40FeO2Si3: C, 71.79; H, 5.35. Found: C,72.00; H, 5.50.
Synthesis of (η5-C9H7)Fe(CO)2SiPh3 (1k). Compound 1k was
synthesized by using the same procedure as described for the
preparation of 1a, starting from 2k (0.58 g, 5.0 mmol),
pentacarbonyliron (1.96 g, 10.0 mmol), and triphenylsilane (1.95 g,
7.5 mmol). The product was obtained as a yellow solid (0.32 g, 13%
yield): mp 172−174 °C (lit.19 mp 166−167 °C). 1H NMR (CDCl3): δ
4.84 (s, 3H, C9H7), 7.32 (m, 11H, C9H7, C6H5), 7.54 (m, 8H, C6H5).
13C NMR (CDCl3): δ 74.15, 92.32, 105.62, 124.53, 127.62, 127.67,
128.41, 135.47, 142.13 (C9H7), 215.17 (CO).
Synthesis of (η5-C5H4SiPh2SiPh3)Fe(CO)2SiPh3 (1e). Com-
pound 1e was synthesized by using the same procedure as described
for the preparation of 1a, starting from 2e (2.02 g, 4.0 mmol),
pentacarbonyliron (1.57 g, 8.0 mmol), and triphenylsilane (1.56 g, 6.0
mmol). The product was obtained as a yellow solid (0.88 g, 25%
1
yield): mp 268−270 °C. IR (KBr): νCO 1943 (s), 1994 (s) cm−1. H
Synthesis of (η5-C5H4SiMe2SiMe2Ph)Fe(CO)2SiMe2Ph (1l).
Compound 1l was synthesized by using the same procedure as
described for the preparation of 1a, starting from 2b (10.3 g, 40.0
mmol), pentacarbonyliron (15.6 g, 80.0 mmol), and phenyl-
dimethylsilane (8.16 g, 60.0 mmol). The product was obtained as a
yellow solid (4.44 g, 22% yield): mp 154−156 °C. IR (KBr): νCO 1922
(s), 1980 (s) cm−1. 1H NMR (CDCl3): δ 0.23 (s, 6H, SiCH3), 0.31 (s,
6H, SiCH3), 0.56 (s, 6H, SiCH3), 4.22 (s, 2H, C5H4), 4.33 (s, 2H,
C5H4), 7.31 (m, 10H, C6H5). 13C NMR (CDCl3): δ −3.95, −3.00,
5.46 (SiCH3), 87.91, 88.47, 91.47 (C5H4), 127.70, 127.94, 128.79,
132.63, 133.92, 138.39, 147.48 (C6H5), 215.88 (CO). Anal. Calcd for
C25H32FeO2Si3: C, 59.50; H, 6.39. Found: C, 59.52; H, 6.59.
NMR (CDCl3): δ 4.31 (s, 2H, C5H4), 4.38 (s, 2H, C5H4), 7.36 (m,
40H, C6H5). 13C NMR (CDCl3): δ 86.74, 89.43, 91.64 (C5H4),
127.51, 128.11, 128.14, 128.20, 129.69, 129.93, 133.25, 133.84, 135.52,
136.60, 136.66, 142.31 (C6H5), 214.99 (CO). Anal. Calcd for
C55H44FeO2Si3: C, 75.32; H, 5.06. Found: C, 75.39; H, 5.34.
Synthesis of (η5-C5H4SiMe3)Fe(CO)2SiPh3 (1f). Compound 1f
was synthesized by using the same procedure as described for the
preparation of 1a, starting from 2f (0.93 g, 6.70 mmol),
pentacarbonyliron (2.62 g, 13.4 mmol), and triphenylsilane (2.60 g,
10.0 mmol). The product was obtained as a yellow solid (0.98 g, 29%
1
yield): mp 162−163 °C. IR (KBr): νCO 1930 (s), 1984 (s) cm−1. H
NMR (CDCl3): δ 0.33 (s, 9H, SiCH3), 4.39 (s, 2H, C5H4), 4.78 (s,
2H, C5H4), 7.34 (m, 9H, C6H5), 7.58 (m, 6H, C6H5). 13C NMR
(CDCl3): δ −0.28 (SiCH3), 86.62, 89.82, 92.43 (C5H4), 127.59,
128.26, 135.60, 142.27 (C6H5), 215.87 (CO). Anal. Calcd for
C28H28FeO2Si2: C, 66.13; H, 5.55. Found: C, 65.95; H, 5.39.
Synthesis of (η5-C5H4SiMe2SiPh3)Fe(CO)2SiMe2Ph (1m). Com-
pound 1m was synthesized by using the same procedure as described
for the preparation of 1a, starting from 2d (1.91 g, 5.0 mmol),
pentacarbonyliron (1.96 g, 10.0 mmol), and phenyldimethylsilane
(1.02 g, 7.5 mmol). The product was obtained as a yellow solid (0.67
g, 21% yield): mp 150−152 °C. IR (KBr): νCO 1922 (s), 1988 (s)
Synthesis of (η5-C5H5)Fe(CO)2SiPh3 (1g).18 Compound 1g was
synthesized by using the same procedure as described for the
preparation of 1a, starting from dicyclopentadiene (4.06 g, 30.8
mmol), pentacarbonyliron (6.03 g, 30.8 mmol), and triphenylsilane
(4.0 g, 15.4 mmol). The product was obtained as a yellow solid (0.67
g, 10% yield, based on Ph3SiH): mp 162−163 °C. 1H NMR (CDCl3):
δ 4.70 (s, 5H, C5H5), 7.35 (m, 9H, C6H5), 7.57 (m, 6H, C6H5). 13C
NMR (CDCl3): δ 85.00 (C5H5), 127.64, 128.30, 135.54, 142.54
(C6H5), 215.58 (CO). Anal. Calcd for C25H20FeO2Si: C, 68.81; H,
4.62. Found: C, 68.99; H, 4.77.
1
cm−1. H NMR (CDCl3): δ 0.49 (s, 6H, SiCH3), 0.64 (s, 6H, CH3),
4.24 (s, 2H, C5H4), 4.35 (s, 2H, C5H4), 7.43 (m, 20H, C6H5). 13C
NMR (CDCl3): δ −1.60, 5.46 (SiCH3), 88.00, 89.12, 90.99 (C5H4),
127.72, 127.96, 128.18, 129.44, 132.64, 134.58, 136.10, 147.47 (C6H5),
215.81 (CO). Anal. Calcd for C35H36FeO2Si3: C, 66.86; H, 5.77.
Found: C, 66.69; H, 5.53.
Synthesis of (η5-C5H4SiPh2SiPh3)Fe(CO)2SiMe2Ph (1n). Com-
pound 1n was synthesized by using the same procedure as described
for the preparation of 1a, starting from 2e (2.53 g, 5.0 mmol),
pentacarbonyliron (1.96 g, 10.0 mmol), and phenyldimethylsilane
(1.03 g, 7.6 mmol). The product was obtained as a yellow solid (0.95
g, 25% yield): mp 154−156 °C. IR (KBr): νCO 1930 (s), 1984 (s)
cm−1. 1H NMR (CDCl3): δ 0.53 (s, 6H, SiCH3), 3.89 (s, 4H,
C5H4),7.33 (m, 30H, C6H5). 13C NMR (CDCl3): δ 5.18 (SiCH3),
88.08, 88.33, 90.37 (C5H4), 127.49, 127.86, 127.95, 129.47, 129.65,
132.44, 133.51, 133.88, 136.48, 146.93 (C6H5), 214.89 (CO). Anal.
Calcd for C45H40FeO2Si3: C, 71.79; H, 5.35. Found: C, 71.55; H, 5.48.
Synthesis of (η5-C5H4CH2Ph)Fe(CO)2SiMe2Ph (1o). Compound
1o was synthesized by using the same procedure as described for the
preparation of 1a, starting from 2i (1.43 g, 9.2 mmol),
pentacarbonyliron (3.62 g, 18.5 mmol), and phenyldimethylsilane
(1.87 g, 13.8 mmol). The product was separated by a column of
neutral alumina, loading samples by the dry method and using hexane
as eluent, to give 1o as a yellow oil (0.55 g, 15% yield). IR (KBr): νCO
Synthesis of (η5-C5H4Me)Fe(CO)2SiPh3 (1h). Compound 1h was
synthesized by using the same procedure as described for the
preparation of 1g, starting from methylcyclopentadiene dimer (2.46 g,
15.4 mmol), pentacarbonyliron (3.02 g, 15.4 mmol), and triphenylsi-
lane (2.0 g, 7.7 mmol). The product was obtained as a yellow solid
(0.45 g, 13% yield, based on Ph3SiH): mp 156−157 °C. IR (KBr): νCO
1934 (s), 1980 (s) cm−1. 1H NMR (CDCl3): δ 1.92 (s, 3H, CH3), 4.38
(s, 2H, C5H4), 4.56 (s, 2H, C5H4), 7.30 (m, 9H, C6H5), 7.54 (m, 6H,
C6H5). 13C NMR (CDCl3): δ 13.30 (CH3), 84.14, 84.82, 103.14
(C5H4), 127.52, 128.13, 135.49, 142.74 (C6H5), 216.07 (CO). Anal.
Calcd for C26H22FeO2Si: C, 69.34; H, 4.92. Found: C, 69.28; H, 5.03.
Synthesis of (η5-C5H4CH2Ph)Fe(CO)2SiPh3 (1i). Compound 1i
was synthesized by using the same procedure as described for the
preparation of 1a, starting from 2i (1.05 g, 6.7 mmol),
pentacarbonyliron (2.62g, 13.4 mmol), and triphenylsilane (2.61 g,
10.0 mmol). The product was obtained as a yellow solid (0.98 g, 28%
1
1
yield): mp 116−118 °C. IR (KBr): νCO 1926 (s), 1980 (s) cm−1. H
1922 (s), 1992 (s) cm−1. H NMR (CDCl3): δ 0.65 (s, 6H, SiCH3),
NMR (CDCl3): δ 3.53 (s, 2H, CH2), 4.38 (s, 2H, C5H4), 4.60 (s, 2H,
C5H4), 7.18 (m, 2H, C6H5), 7.31 (m, 12H, C6H5), 7.56 (m, 6H,
C6H5). 13C NMR (CDCl3): δ 34.08 (CH2), 84.56, 84.61, 106.76
(C5H4), 126.89, 127.63, 128.27, 128.63, 128.78, 135.56, 139.24, 142.63
(C6H5), 215.99 (CO). Anal. Calcd for C32H26FeO2Si: C, 73.00; H,
4.98. Found: C, 73.06; H, 5.11.
3.26 (s, 2H, CH2), 4.29 (s, 2H, C5H4), 4.56 (s, 2H, C5H4), 7.07 (m,
2H, C6H5), 7.20 (m, 3H, C6H5), 7.33 (m, 3H, C6H5), 7.61 (m, 2H,
C6H5). 13C NMR (CDCl3): δ 5.27 (SiCH3), 33.87 (CH2), 83.05,
85.14, 104.31 (C5H4), 126.68, 127.78, 128.02, 128.45, 128.64, 132.65,
139.73, 147.33 (C6H5), 215.86 (CO). Anal. Calcd for C22H22FeO2Si:
C, 65.67; H, 5.51. Found: C, 65.80; H, 5.35.
Crystallographic Analysis. Yellow single crystals of complexes
1e,h,l suitable for an X-ray structural determination were obtained by
recrystallization from CH2Cl2/hexane solvents. All measurements were
carried out on a Rigaku Saturn 70 diffractometer equipped with a
Synthesis of (η5-MeC5H3SiMe3)Fe(CO)2SiPh3 (1j). Compound
1j was synthesized by using the same procedure as described for the
preparation of 1a, starting from 2j (1.22 g, 8.0 mmol),
pentacarbonyliron (2.62 g, 16.0 mmol), and triphenylsilane (3.12 g,
1713
dx.doi.org/10.1021/om500066y | Organometallics 2014, 33, 1710−1714

Organometallics
Article
rotating anode system at 113(2) K by using graphite-monochromated
Mo Kα radiation (ω−2θ scans, λ = 0.71073 Å). The structures were
solved by direct methods and refined by full-matrix least squares. All
calculations were performed by using the SHELXL-97 program
system. Hydrogen atoms were added theoretically and refined with
isotropic thermal parameters. Crystal and structure refinement data
and bond lengths and angles are shown in Tables S1−S7 in the
Supporting Information.
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ASSOCIATED CONTENT
* Supporting Information
■
S
́
Pannell, K. H. Inorg. Chim. Acta 2008, 361, 1793−1796. (d) Ramırez-
Figures, tables and CIF files giving crystallographic data for
1e,h,l. This material is available free of charge via the Internet at
http://pubs.acs.org.
Oliva, E.; Cuadrado, I.; Casado, C. M.; Losada, J.; Alonso, B. J.
Organomet. Chem. 2006, 691, 1131−1137. (e) Zhang, Y.; Cervantes-
Lee, F.; Pannell, K. H. Organometallics 2003, 22, 2517−2524.
(f) Zhang, Y.; Pannell, K. H. Organometallics 2003, 22, 1766−1770.
(g) Malisch, W.; Jehle, H.; Schumacher, D.; Binnewies, M.; Soger, N. J.
AUTHOR INFORMATION
Corresponding Author
*E-mail for H.S.: sunhl@nankai.edu.cn.
̈
■
Organomet. Chem. 2003, 667, 35−41. (h) Grogger, C.; Fallmann, H.;
Furpaß, G.; Stuger, H.; Kickelbick, G. J. Organomet. Chem. 2003, 665,
̈
̈
186−195. (i) Zhang, Y.; Cervantes-Lee, F.; Pannell, K. H. Organo-
Notes
metallics 2002, 21, 5859−5867. (j) McIndoe, J. S.; Nicholson, B. K. J.
Organomet. Chem. 2002, 648, 237−245. (k) Malisch, W.; Vogler, M.;
̈
The authors declare no competing financial interest.
Schumacher, D.; Nieger, M. Organometallics 2002, 21, 2891−2897.
(l) Sharma, S.; Pannell, K. H. Organometallics 2000, 19, 1225−1231.
(m) Sharma, H. K.; Pannell, K. H. Organometallics 2001, 20, 7−9.
(n) Zhang, Y.; Pannell, K. H. Organometallics 2002, 21, 503−510.
(o) Zhang, Y.; Cervantes-Lee, F.; Pannell, K. H. J. Organomet. Chem.
2001, 634, 102−108.
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2775. (b) Harrod, J. F.; Pelletier, E. Organometallics 1984, 3, 1064−
1069.
ACKNOWLEDGMENTS
■
We thank the National Natural Science Foundation of China
(Nos. 20372036 and 20421202), the Natural Science
Foundation of Tianjin (No. 08JCZDJC21600), and the
Ministry of Education of China (No. 03406) for financial
support.
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S.; Conville, J. J. Organomet. Chem. 1970, 23, 357−359. (c) Sun, H.;
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