Synthesis, structural characterization and reactivity of the (ferriomethyl)silanols C5R5(OC)2Fe-CH2-SiMe(R′)OH (R = H, Me; R′ = Me, Ph)

Article abstract of DOI:10.1002/1099-0682(200212)2002:12<3242::AID-EJIC3242>3.0.CO;2-Q

The novel (ferriomethyl)-substituted silanols C₅R₅(OC)₂Fe-CH₂-SiMe(R′)OH [R = H, R′ = Me (4a), Ph (4b); R = Me, R′ = Me (4c)] are obtained by hydrolysis of the chloro(ferriomethyl)silanes C₅R₅

Full text of DOI:10.1002/1099-0682(200212)2002:12<3242::AID-EJIC3242>3.0.CO;2-Q

FULL PAPER
Synthesis, Structural Characterization and Reactivity of the
(Ferriomethyl)silanols C5R5(OC)2Fe؊CH2؊SiMe(RЈ)OH
(R ؍ H, Me; RЈ ؍ Me, Ph)[‡]
Wolfgang Malisch,*[a] Marco Hofmann,[a] Martin Nieger,[b] Wolfgang W. Schöller,[c] and
Andreas Sundermann[c]
Keywords: Silicon / Iron / Oxygenation / (Metalloalkyl)silanols / Density functional calculations
The
novel
(ferriomethyl)-substituted
silanols
situation
in
the
related
(ferriomethyl)silanol
C5R5(OC)2Fe−CH2−SiMe(RЈ)OH [R = H, RЈ = Me (4a), Ph (4b);
R = Me, RЈ = Me (4c)] are obtained by hydrolysis of the
Cp(OC)2Fe−CH2−SiH2OH has been analyzed on the basis of
density functional calculations. 4a shows self-condensation
to give the 1,3-bis(ferriomethyl)disiloxane [Cp(OC)2-
Fe−CH2−SiMe2]2O (5), which is also obtained by the reaction
of 4a with 3a. Analogous treatment of 4a with the chloro(or-
chloro(ferriomethyl)silanes
C5R5(OC)2Fe−CH2−SiMe(RЈ)Cl
[R = H, RЈ = Me (3a), Ph (3b); R = Me, RЈ = Me (3c)] in the
presence of Et3N. Another access to this class of compounds
is offered by the oxygenation of Si−H-functional (ferriome- gano)silanes R(RЈ)Si(Me)Cl (R = H, RЈ = Me, p-Tol; R = RЈ =
thyl)silanes with dimethyldioxirane, as shown for 4a by the
oxo-functionalization of the (ferriomethyl)silane Cp(OC)2-
Fe−CH2−SiMe2H (3d). 4a−c have been characterized spectro-
scopically and by X-ray structure analyses showing the
formation of tube- or chain-like arrangements in the solid
state caused by hydrogen bonding. In addition, the bonding
Me)
yields
the
monometalated
disiloxanes
Cp(OC)2Fe−CH2−Si(Me)2OSi(Me)(R)RЈ [R = H, RЈ = Me (6a),
p-Tol (6b); R = RЈ = Me (6c)].
( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany,
2002)
Introduction
Another approach to transition metal substituted silox-
anes involves the synthesis of metallosilanols of the general
Transition metal substituted siloxanes represent attractive type LnMϪSi(R)3Ϫn(OH)n (n ϭ 1Ϫ3)[19Ϫ34] and their
model compounds for catalytically active transition metal extensive condensation with chlorosilanes giving access to
complexes anchored on silica surfaces.[2Ϫ5] They offer an metallosiloxanes with a direct metalϪsilicon bond. In this
opportunity to determine the reaction mechanisms of het- context, metallosilanols containing the metal fragments
erogeneous catalyzed reactions on a molecular level in order C5R5(OC)2(Me3P)M (M ϭ Mo, W; R ϭ H, Me),[19Ϫ24]
to improve the selectivity, activity and lifetime of a hetero- C5R5(OC)2M (M
ϭ
Fe, Ru;
R
ϭ
H, Me),[23Ϫ27]
(dcpe)(Ph)Pt,[30]
geneous catalyst. As a consequence many of those model (Ph3P)2(OC)(Cl)Os,[28]
(OC)5Cr,[29]
compounds have been synthesized in the last few years of- (Et3P)2(Cl)(H)Ir[33] and Cp2(H)Mo[34] have been realized.
ten starting from stable organosilanetriols[6Ϫ10] or incom- Due to the strong electron-releasing effect of the metal frag-
pletely condensed silsesquioxanes[11Ϫ18] which can react ment the acidity of the SiϪOH proton and the tendency
with various metal complexes resulting in the formation of towards self-condensation are strongly decreased. This situ-
metallosiloxanes with the structural unit LnMϪOϪSi, i.e. a ation offers the possibility of isolating metal derivatives
silanolate ligand sphere around the transition metal centre. with an Si(OH)3 unit,[20,28] which are synthetically useful
for the generation of well-defined metallosiloxanes by con-
trolled co-condensation processes.
[‡]
Synthesis and Reactivity of Silicon Transition Metal
Complexes, 52. Metallosilanols and Metallosiloxanes, 24. Part
51/23: Ref.[1]
In recent years, two routes Ϫ hydrolysis of chloro(metal-
lo)silanes in the presence of an auxiliary base[23Ϫ25] and
oxo-functionalization of hydrido(metallo)silanes with the
mild oxidizing agent dimethyldioxirane[31,32,35Ϫ37] Ϫ proved
to be most efficient for the generation of metallosilanols.
The electrophilic oxygen insertion is especially productive
for metallosilanes with electron-rich SiϪH bonds provided
by metal fragments with high donor capacity. For these sys-
[a]
Institut für Anorganische Chemie der Universität Würzburg,
Am Hubland, 97074 Würzburg, Germany
Fax: (internat.) ϩ 49-(0)931/888-4618
E-mail: Wolfgang.Malisch@mail.uni-wuerzburg.de
Institut für Anorganische Chemie der Universität Bonn,
Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
Fakultät für Chemie der Universität Bielefeld,
Postfach 100131, 33501 Bielefeld, Germany
E-mail: Wolfgang.Schoeller@uni-bielefeld.de
[b]
[c]
3242  2002 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim 1434Ϫ1948/02/1212Ϫ3242 $ 20.00ϩ.50/0 Eur. J. Inorg. Chem. 2002, 3242Ϫ3252

Synthesis, Structural Characterization and Reactivity of (Ferriomethyl)silanols
FULL PAPER
tems the hydrolysis of the analogous chloro(metallo)silanes after reaction periods of 16Ϫ36 h at room temperature
fails since the electrophilicity of the silicon atom is too (Scheme 1).[53] The heterogeneous method using cyclohex-
weak.
ane as a solvent proved to be advantageous over the homo-
Our interest has now turned to silanols having the geneous one using THF because of the formation of consid-
SiϪOH moiety separated from the metal fragment by a erable amounts of undesirable by-products in the latter case.
methylene group in order to check the ‘‘transition metal
In the synthesis of 3a,b metallation of 2a,b occurs prim-
effect’’ on silanol units that are not directly bound to the arily at the silicon atom. The initially formed ferriosilanes
transition metal atom. The spacer group should also help Cp(OC)2FeϪSiMe(RЈ)(CH2Cl) [RЈ ϭ Me (3aЈ), Ph (3bЈ)]
to suppress undesirable decomposition reactions involving can be subsequently converted into the chloro(ferriomethyl)-
‘‘β-hydrogen abstraction’’ from the SiϪOH group, observed silanes 3a,b by thermal rearrangement at 120 °C. In the case
for ferriosilanols of the type Cp(OC)2FeϪSi(R)(RЈ)OH (R, of 3a this rearrangement is nearly quantitative after 1
RЈ ϭ alkyl, aryl).[38]
h,[44,45] whereas in the other case a mixture of the two iso-
Although the Me3SiCH2 ligand has found wide applica- mers is produced after heating for 3 h (3b/3bЈ ഠ 80:20),
tion in transition metal chemistry due to its inertness with from which 3b can be separated by crystallization at Ϫ78
respect to β-hydride abstraction,[39Ϫ41] only a few examples °C from n-pentane. Prolonged heating and a higher temper-
exist in the literature with a silylmethyl ligand having one ature lead to extensive decomposition of 3b.
or more functional groups at the silicon atom.[42Ϫ52] These
In the metallation of 2a with the pentamethylcyclopenta-
compounds have been used as precursors in the synthesis dienyl-substituted ferrate 1b no isomer of 3c is detected; 3c
of silene transition metal complexes, which were originally is obtained directly at room temperature after appropriate
proposed by Pannell[42] as intermediates in the β-elimina- workup in a moderate yield of 33% due to the formation
tion reaction of Cp(OC)2FeϪCH2ϪSiMe2H and were spec- of considerable amounts of C5Me5(OC)2FeϪCl, which are
troscopically observed by Wrighton et al. by low-temper- removed by repeated fractional crystallization at Ϫ20 °C.
ature near-UV photolysis of C5R5(OC)3WϪCH2ϪSiMe2H
The SiϪH-functional (ferriomethyl)silane 3d is obtained
(R ϭ H, Me)[46] and C5Me5(OC)2FeϪCH2ϪSiMe2H.[47] analogously by nucleophilic metallation of ClCH2SiMe2H
The chloro-functional (silylmethyl)tungsten complex (2c) with 1a in THF.[42,43]
Cp2W(Cl)ϪCH2ϪSiMe2Cl has been used by Berry et al. to
Synthesis of (Ferriomethyl)silanols (4a؊c)
generate a stable silene transition metal complex by reduct-
ive dechlorination with magnesium.[48]
The (ferriomethyl)silanol Cp(OC)2FeϪCH2ϪSiMe2OH
(4a) is available by hydrolysis of 3a in diethyl ether in the
presence of the auxiliary base Et3N. It can be isolated after
2 h at room temperature in 89% yield (Scheme 2, route a).
A second approach to 4a involves oxygenation of 3d with
dimethyldioxirane in acetone after 2 h (Ϫ78 °C to room
temp.) in 67% yield (Scheme 2, route b). The oxygenation
route guarantees a more convenient workup procedure but
proved to be inferior to the hydrolysis route with respect to
the lower yield of the resulting silanol 4a, presumably due
to oxidative decomposition reactions at the metal fragment.
No attempts so far have been made to generate or isolate
any (metallomethyl)-substituted silanols from these silicon-
functional complexes. Here we report on the synthesis of
the first (ferriomethyl)-substituted silanols bearing
a
methylene group between the silanol and the iron fragment.
Results and Discussion
Synthesis of Si؊Cl- and Si؊H-Functional
(Ferriomethyl)silanes (3a؊d)
The chloro-functional (ferriomethyl)silanes C5R5-
(OC)2FeϪCH2ϪSiMe(RЈ)Cl [R ϭ H, RЈ ϭ Me (3a), Ph
(3b); R ϭ Me, RЈ ϭ Me (3c)] are obtained by nucleophilic
metallation of the organosilanes ClCH2SiMe(RЈ)Cl [RЈ ϭ
Me (2a); Ph (2b)] with the sodium ferrates Na[Fe-
(CO)2C5R5] [R ϭ H (1a), Me (1b)] in THF or cyclohexane
Scheme 2. Synthesis of the (ferriomethyl)silanols 4aϪc by hydro-
Scheme 1. Synthesis of the (ferriomethyl)silanes 3aϪd
Eur. J. Inorg. Chem. 2002, 3242Ϫ3252
lysis or oxygenation
3243

W. Malisch, M. Hofmann, M. Nieger, W. W. Schöller, A. Sundermann
FULL PAPER
For the synthesis of the (ferriomethyl)silanols
C5R5(OC)2FeϪCH2ϪSi(Me)(RЈ)OH [R ϭ H, RЈ ϭ Ph
(4b); R ϭ Me, RЈ ϭ Me (4c)] only the hydrolysis route
(Scheme 2, route a) has been applied; 4b,c can be isolated
after reaction periods of 4 h at room temperature in the
presence of Et3N in yields of 74% (4b) and 40% (4c), re-
spectively.
The (ferriomethyl)silanols 4aϪc are obtained as slightly
air-sensitive yellow-brown waxy solids [m.p. 38 °C (4a), to
89 °C (4c)], which show good solubility in diethyl ether and
aromatic solvents like benzene and toluene and are rather
soluble even in aliphatic solvents like n-pentane. They are
characterized in the IR spectrum by the OH stretching band
at ν˜ ϭ 3698 cmϪ1 (4a), 3682 cmϪ1 (4b) and 3703 cmϪ1 (4c)
1
(n-pentane solution), and in the H NMR spectrum (C6D6)
by a broad signal for the hydroxy proton at δ ϭ 0.95 (4a),
1.28 (4b) and 0.92 (4c) ppm. The characteristic upfield sig-
nal of the CH2 protons is detected at δ ϭ Ϫ0.42 (4a) and
Ϫ0.62 (4c) ppm. In the case of 4b, the asymmetric silicon
atom leads to diastereotopic CH2 protons which are de-
tected as pair of doublets at δ ϭ Ϫ0.09 and Ϫ0.38 ppm. In
the 13C NMR spectra the signals for the CH2 group are
observed between δ ϭ Ϫ12.4 (4c) and Ϫ24.5 (4b) ppm. The
chemical shifts in the 29Si NMR spectra [δ ϭ 21.8 (4a),
11.7 (4b), 21.1 (4c) ppm] reveal a decreased influence of
the transition metal fragment on the silicon atom in the β-
position. For example, in the case of 4a, the signal is shifted
by approximately 44 ppm to a higher field compared with
its counterpart Cp(OC)2FeϪSiMe2OH (δ ϭ 66.1 ppm)[1]
without a methylene bridge.
Figure 1. ORTEP view of Cp(OC)2FeϪCH2ϪSiMe2OH (4a),
showing the two crystallographically independent molecules; hy-
drogen atoms have been omitted for clarity (except for those at
˚
C8 and O3); selected bond lengths [A] and angles [°]: Fe1ϪCp(Z)
1.728(2)/1.730(2),
Fe1ϪC8
2.0896(16)/2.0863(17),
C8ϪSi1
1.8451(17)/1.8508(16), Si1ϪO3 1.6599(13)/1.6558(13), Si1ϪC10
1.8596(19)/1.8686(19), Si1ϪC9 1.8668(17)/1.8508(18);
X-ray Analyses of 4a؊c
C1ϪFe1ϪC2 93.61(8)/93.15(7), C1ϪFe1ϪC8 89.38(8)/92.32(8),
Final evidence for the structural assignments of 4aϪc is C2ϪFe1ϪC8 87.20(7)/85.94(7), Cp(Z)ϪFe1ϪC1 126.8(2)/126.3(2),
given by single-crystal X-ray structure determinations
Cp(Z)ϪFe1ϪC2 125.1(1)/126.5(1), Cp(Z)ϪFe1ϪC8 123.4(1)/
121.6(1),
Fe1ϪC8ϪSi1
120.36(8)/120.51(8),
C8ϪSi1ϪO3
(Figures 1Ϫ3). In the case of 4a, two crystallographically
independent molecules have been found in the asymmetric
unit.
The crystal structures of 4aϪc reveal a pseudo-octahed-
ral coordination sphere at the iron atom, indicated by the
ligandϪironϪligand angles close to 90°. The largest one is
108.41(7)/114.90(7), C9ϪSi1ϪO3 102.63(7)/104.03(8); selected tor-
sion angles [°]: Fe1ϪC8ϪSi1ϪO3 Ϫ174.24(8)/40.09(12),
C1ϪFe1ϪC8ϪSi1
71.72(12)/Ϫ77.92(12)
70.57(11)/57.31(11),
Fe1ϪC8ϪSi1ϪC9
in all cases found between the carbonyl carbon atoms lying in sharp contrast to 4a,b and probably a consequence of
between 97.52(9)° (4c) and 93.15(7)° (4a), while the angles the higher steric demand of the C5Me5 ligand.
between the methylene carbon atom and the CO ligands are
slightly smaller [92.00(8)° (4c), to 85.94(7)° (4a)].
The lengths of the ironϪmethylene bonds lie in a close
range between 2.0931(18) (4b) and 2.0775(16) A (4c) and
˚
The conformation along the ironϪmethylene bond re- are similar to other C5R5(OC)2FeϪCR3 complexes bearing
veals a distorted staggered pseudo-ethane arrangement. In an sp3-carbon atom at the iron atom.[54Ϫ56]
the case of 4a,b the SiR3 substituent adopts a nearly ‘‘anti’’
The FeϪCϪSi bond angle is in all cases wider than the
position to one of the CO groups [C2ϪFe1ϪC8ϪSi1 tetrahedral angle and is up to 124.89(9)° for 4c, which is in
164.21(11)/150.30(11)° (4a), Ϫ161.32(11)° (4b)] and is posi- agreement with a higher s-character of the carbon orbital
tioned between the cyclopentadienyl and the other carbonyl interactions with the more electropositive iron and silicon
ligand, but as the dihedral angles indicate in the case of 4a, atoms according to Bent’s rule,[57,58] but also shows the
that a major difference exists concerning the orientation in higher steric demand of the iron and silanol groups in com-
the two different molecules of the asymmetric unit (see parison to the H atoms at the methylene carbon atom.
also below).
This finding parallels that for the complexes
Looking at 4c, the silanol group is positioned between Cp(OC)(Ph3P)FeϪCH2ϪSiMe3 [FeϪCϪSi 122.8(2)°],[59]
the two carbonyl ligands [C1BϪFe1ϪC11ϪSi1 41.70(12)°; Cp(OC)2FeϪCH2ϪSiMe2ϪSiMe2ϪFe(CO)2Cp [FeϪCϪSi
C1AϪFe1ϪC11ϪSi1 Ϫ55.91(12)°] in a mutually ‘‘anti’’ po- 123.4(2)°][60] and meso-[Cp(OC)2FeϪCH2ϪSi(Me)(Ph)]2
sition to the pentamethylcyclopentadienyl group, which is [FeϪCϪSi 120.5(1)°][61] which, to the best of our know-
3244
Eur. J. Inorg. Chem. 2002, 3242Ϫ3252

Synthesis, Structural Characterization and Reactivity of (Ferriomethyl)silanols
FULL PAPER
ones to the methylene carbon atom [114.89(8) (4b) to
114.29(10)° (4c)].
Looking at the arrangement of the substituents along the
methyleneϪsilicon bond, in the case of 4b there is a nearly
ideal ‘‘anti’’ arrangement of the iron fragment and the
phenyl group, with a small deviation of only about 6°
[Fe1ϪC8ϪSi1ϪC10 173.59(8)°], whereas in the case of 4c
the hydroxy group adopts the ‘‘anti’’ position to the iron
fragment [Fe1ϪC11ϪSi1ϪO1 169.61(10)°] with a deviation
of about 10°.
The situation in the case of 4a is a bit more complex. The
two different molecules are characterized by a nearly ideal
‘‘anti’’ position of the iron atom and the hydroxy group
Figure 2. ORTEP view of Cp(OC)2FeϪCH2ϪSi(Me)(Ph)OH (4b);
hydrogen atoms have been omitted for clarity (except for those at
˚
C8 and O3); selected bond lengths [A] and angles [°]: Fe1ϪCp(Z)
1.734(1), Fe1ϪC8 2.0931(18), C8ϪSi1 1.8464(18), Si1ϪO3 [Fe1ϪC8ϪSi1ϪO3 Ϫ174.24(8)] in the one case and a
1.6645(13), Si1ϪC9 1.8598(18), Si1ϪC10 1.8825(19); C1ϪFe1ϪC2
‘‘gauche’’ position of these ligands with a more significant
93.38(9),
C1ϪFe1ϪC8
90.98(8), C2ϪFe1ϪC8
86.42(8),
126.2(1),
deviation from ideal conformation of about 20°
[Fe1ϪC8ϪSi1ϪO3 40.09(12)°] in the other. This situation
is clearly a consequence of the formation of a polymeric
arrangement of the molecular subunits based on hydrogen
bonding (see also below).
Cp(Z)ϪFe1ϪC1
126.2(1),
Cp(Z)ϪFe1ϪC2
Cp(Z)ϪFe1ϪC8 122.4(1), Fe1ϪC8ϪSi1 116.14(9), C8ϪSi1ϪO3
112.18(7), C9ϪSi1ϪO3 104.72(8), C8ϪSi1ϪC9 114.89(8),
O3ϪSi1ϪC10
105.80(7);
selected
torsion
angles
[°]:
Fe1ϪC8ϪSi1ϪO3 Ϫ67.89(10), Fe1ϪC8ϪSi1ϪC10 173.59(8),
C1ϪFe1ϪC8ϪSi1 Ϫ68.00(10), Fe1ϪC8ϪSi1ϪC9 51.55(12)
Triorganosilanols often show interesting hydrogen-
bonded superstructures, the pattern of which depends on
the nature of the organic substituents.[65] In contrast
to the structures of other diorgano(metallo)silanols
LnMϪSiR2OH, which prefer hydrogen-bonded ‘‘dimeriz-
ation’’, e.g. C5Me5(OC)2FeϪSiMe2OH[1] and C5Me5-
(OC)2RuϪSi(o-Tol)2OH,[26] in the case of the (ferriomethyl)-
silanols 4a,b strong intermolecular OH···O bridges lead to
the formation of discrete tetrameric units in the solid state,
indicated by O···O distances of 2.7320(16)/2.7410(17) (4a)
˚
and 2.6965(17) A (4b). This arrangement is similar to that
found for Ph3SiOH.[62]
Looking at 4a, the tetramers consist of the two types of
staggered conformers, concerning the C8ϪSi bond (see
above). They are formed by an alternating arrangement of
Figure 3. ORTEP view of C5Me5(OC)2FeϪCH2ϪSiMe2OH (4c);
hydrogen atoms have been omitted for clarity (except for those at
˚
C11 and O1); selected bond lengths [A] and angles [°]:
Fe1ϪC5Me5(Z) 1.759(2), Fe1ϪC11 2.0775(16), C11ϪSi1
1.8477(17), Si1ϪO1 1.6589(12), Si1ϪC12 1.859(2), Si1ϪC13
1.865(2); C1BϪFe1ϪC1B 97.52(9), C1BϪFe1ϪC11 92.17(7),
C1AϪFe1ϪC11
92.00(8),
C5Me5(Z)ϪFe1ϪC1A
122.2(1),
C5Me5(Z)ϪFe1ϪC1B 124.1(1), C5Me5(Z)ϪFe1ϪC11 120.7(1),
Fe1ϪC11ϪSi1 124.89(9), C11ϪSi1ϪO1 106.66(7), C12ϪSi1ϪO1
106.39(8), C11ϪSi1ϪC12 113.72(9), O1ϪSi1ϪC13 107.53(10),
C11ϪSi1ϪC13 114.29(10), C12ϪSi1ϪC13 107.78(13); selected tor-
sion
angles
[°]:
C1BϪFe1ϪC11ϪSi1
41.70(12),
C1AϪFe1ϪC11ϪSi1 Ϫ55.91(12), Fe1ϪC11ϪSi1ϪO1 169.61(10),
Fe1ϪC11ϪSi1ϪC12 Ϫ73.43(13), Fe1ϪC11ϪSi1ϪC13 50.93(16)
ledge, are the only other structurally characterized com-
pounds with a CpL2FeϪCH2ϪSiR3 (L ϭ CO, PPh3)
moiety.
The SiϪO bond lengths with values between 1.6645(13)
˚
(4b) and 1.6558(13) A (4a) are nearly identical and lie
within the range of other organo- and metallo-substituted
silanols.[19Ϫ34,62Ϫ65] The silicon atom shows in all cases a
distorted tetrahedral arrangement of substituents with the
expected smaller angle between the OH and CH3
Figure 4. Ladder-type connection of 4a between the ‘‘anti’’ con-
group[57,58] [106.39(8) (4c) to 102.63(7)° (4a)] and enlarged formers of neighboring tetramers via CH···OC bridges
Eur. J. Inorg. Chem. 2002, 3242Ϫ3252
3245

W. Malisch, M. Hofmann, M. Nieger, W. W. Schöller, A. Sundermann
FULL PAPER
the ‘‘anti’’ and ‘‘gauche’’ conformers and exhibit a centre
of symmetry.
The tetrameric units are stacked on top of each other in
the same way, resulting in a tube-like arrangement of the
The tetrameric units are connected to each other in a SiϪOH moieties, which can be seen from Figure 5. The
ladder-type fashion by weak CH···OC interactions of the tubes can be considered as hydrophilic channels inside a
˚
Cp and one CO ligand [C4···O1 3.358(3) A] between two lipophilic shape of the remaining (ferriomethyl) fragments.
‘‘anti’’ conformers of neighbouring units, as depicted in Between atoms of different tubes there are no or only mar-
Figure 4. This kind of hydrogen bonding, although very ginal interactions, indicated by C···O distances of more than
˚
rare, has recently been found by Braga et al. in the struc- 3.70 A.
tures of [Cp(CO)2Fe]2 and Cp2Fe2(CO)2(µ-CO)(µ-
In the case of 4b, the situation is similar, but in contrast
to 4a there are no conformational isomers in the crystal
structure, but two pairs of enantiomers which form the
tetramer. The enantiomers are linked in an alternate fashion
by hydrogen bonding to produce the centrosymmetric tetra-
CHMe).[66,67]
Figure 9. Population analysis of Cp(OC)2FeϪX (X ϭ CH3, CH2Si-
H2OH), NBO charges and Wiberg bond indices (in italics); in par-
entheses are FeϪX equilibrium distances
Figure 5. View inside the tube-like arrangement of the tetrameric
units of 4a
Figure 6. View inside the tube-like arrangement of the tetrameric units of 4b with connection of the tubes via CH···OC bridges; hydrogen
atoms (except for those involved in hydrogen bonding) as well as the phenyl carbon atoms (except for the ipso carbon atom) have been
omitted for clarity
3246
Eur. J. Inorg. Chem. 2002, 3242Ϫ3252

Synthesis, Structural Characterization and Reactivity of (Ferriomethyl)silanols
FULL PAPER
˚
˚
mer. Like 4a, the tetramers are stacked on top of each other puted 2.088 A, experimental 2.089 A). The calculations also
to produce a tube-like arrangement (Figure 6). These tubes predict a widened valent angle at the carbon atom [X ϭ
are linked by weak CH···OC interactions of the Cp and one CH2SiH2(OH): FeϪCϪSi ϭ 115.7°], in agreement with the
CO ligand of two enantiomers with the same configuration expectations from Bent’s rule.[57,58] It is of interest to ana-
˚
of neighboring tubes [C7···O1 3.406(2) A].
lyze the electron density distributions within the calculated
The situation for the (ferriomethyl)silanol 4c is somehow structures. The substituent X (CH3, CH2SiH2OH) is only
different. The molecules are connected by OH···O bridges weakly bound to the metal atom (Wiberg bond index for
giving rise to the formation of an infinite chain structure. FeϪC 0.59 vs. 0.55), as compared with a stronger coordina-
This arrangement is a result of a ‘‘flip mechanism’’ of the tion of the carbonyl units (bond index 0.89 vs. 0.90). Inter-
disordered SiϪOH proton[68] which guarantees the linkage estingly, the iron atom accumulates negative charge, al-
of the molecules in two directions (intermolecular O···O though the overall metal fragment releases electron density
˚
distance 2.751/2.789 A). This connection via hydrogen to X. The electron-withdrawing effect of X (ϪI) is more
bonding is repeated in an infinite fashion to result in the strongly pronounced for X ϭ CH2SiH2OH than for X ϭ
formation of a linear chain structure, as depicted in Fig- CH3.
ure 7.
Condensation Behavior of 4a
Although 4a can be stored at Ϫ20 °C for several months
without any self-condensation, at room temperature, this
process slowly starts even in the solid state, leading to the
1,3-bis(ferriomethyl)disiloxane 5.[43] The disiloxane forma-
tion also occurs in solution, which was proven by mon-
itoring a C6D6 solution by NMR spectroscopy. In this case,
5 is formed in 33% yield after 30 d.
The disiloxane 5 is additionally obtained by the reaction
of 4a with the chloro(ferriomethyl)silane 3a in diethyl ether
in the presence of the auxiliary base Et3N after a reaction
period of 3 d at room temperature (Scheme 3).
Disiloxanes with only one iron fragment are available in
the same manner using the chlorosilanes R(RЈ)Si(Me)Cl
(R ϭ H, RЈ ϭ Me, p-Tol; R ϭ RЈ ϭ Me) (Scheme 4). The
(ferriomethyl)-substituted disiloxanes 5 and 6aϪc are ob-
tained in good yields of 76Ϫ85% as orange-brown (5) and
yellow-brown oils (6aϪc), respectively, which can be stored
under nitrogen at room temperature for several months
without decomposition.
The dinuclear disiloxane 5 shows a characteristic upfield
shift of δ ϭ 9 ppm in the 29Si NMR spectrum compared to
the silanol 4a [δ ϭ 12.8 (5) versus 21.8 (4a) ppm], which
finds its counterpart in the resonances of triorganosilanols
and the corresponding disiloxanes.[75]
Figure 7. Chain structure of 4c via OH···O bridges of the disor-
dered SiOH proton
In accordance with this finding, the 29Si NMR reson-
ances of the β-Si atom of 6aϪc are observed at δ ϭ 15.9
(6a), 17.0 (6b) and 13.8 (6c) ppm. The SiϪH-functionalized
disiloxanes 6a,b offer the possibility of further functionaliz-
ation. In this context, experiments to effect SiϪH/SiϪOH
transformation are under investigation, as well as oxidative
addition reactions to electronically unsaturated metal frag-
ments.
These chains interact by weak CH···OC contacts of
the C5Me5 and one CO ligand with intermolecular
˚
C···O distances lying between 3.409(2) and 3.632(3) A
(Figure 8).
DFT Calculations
In order to analyze the bonding situation in the (ferri-
omethyl)silanol 4a in more detail, we performed density
functional calculations[69] on the model compounds
Cp(OC)2FeϪX (X ϭ CH3, CH2SiH2OH). Plots of their
Conclusion
The results of this paper demonstrate that (ferriomethyl)-
equilibrium structures, determined at BP86/SBK(d) substituted silanols are accessible either by Cl/OH exchange
level,[70Ϫ73] are shown in Figure 9, together with the results at the silicon atom of chloro(ferriomethyl)silanes or by oxy-
of a natural bond orbital population analysis (NBO).[74]
gen insertion into the SiϪH bond of the corresponding (fer-
The bonding parameters for X ϭ CH2SiH2OH are in riomethyl)silanes. They show interesting structural features,
agreement with the X-ray investigation on 4a (FeϪC: com- like aggregation to tetramers and the formation of tube- or
Eur. J. Inorg. Chem. 2002, 3242Ϫ3252
3247

W. Malisch, M. Hofmann, M. Nieger, W. W. Schöller, A. Sundermann
FULL PAPER
Figure 8. Connection of the chains of 4c via CH···OC interactions
from triorganosilanols. Apart from that, these compounds
are ideal precursors to perform controlled reactions with
chlorosilanes to generate novel transition metal containing
siloxanes.
Current work deals with the generation of (ferriomethyl)-
substituted silanediols and silanetriols in order to check the
capability of these species to create metal-substituted oligo-
or polysiloxanes by controlled self-condensation reactions.
Scheme 3. Synthesis of the 1,3-bis(ferriomethyl)disiloxane 5
Experimental Section
General Remarks: All operations were performed under purified
and dried nitrogen using Schlenk-type techniques. Solvents were
dried according to conventional procedures, distilled and saturated
with N2 prior to use. NMR: Jeol Lambda 300 (300.4 MHz,
75.5 MHz, and 59.6 MHz for 1H, 13C, and 29Si, respectively).
[D6]Benzene as a solvent: δH ϭ 7.15 ppm, δC ϭ 128.0 ppm; for 29Si
rel. to TMS external. IR: PerkinϪElmer 283 grating spectrometer.
Melting points: differential thermo analysis (Du Pont 9000 Ther-
mal Analysis System). Elemental analyses were performed in the
laboratories of the Institut für Anorganische Chemie der Univer-
sität Würzburg. Starting materials were prepared according to liter-
ature procedures: Na[Fe(CO)2Cp],[76] Na[Fe(CO)2C5Me5],[77]
ClCH2Si(Me)(Ph)Cl,[78] Cp(OC)2FeϪCH2ϪSiMe2H,[43] Cp(OC)2-
FeϪCH2ϪSiMe2Cl,[45] ClSi(Me)(p-Tol)H[79] and dimethyldioxir-
ane.[37] ClCH2SiMe2Cl, ClSiMe2H and ClSiMe3 were purchased
commercially and distilled prior to use.
Scheme 4. Synthesis of the (ferriomethyl)disiloxanes 6aϪc
chain-like arrangements, which is a consequence of inter-
molecular hydrogen bonding.
The stability of this type of metal fragment substituted
silanols with respect to self-condensation is reduced, com-
pared with the ferriosilanols C5R5(OC)2FeϪSiMe2OH
(R ϭ H, Me)[1] bearing the SiϪOH unit directly at the
transition metal atom. As a consequence, the silanol 4a un-
1.
Chloro{[dicarbonyl(η5-cyclopentadienyl)ferrio]methyl}methyl-
dergoes condensation to a disiloxane, which is well known (phenyl)silane (3b): A stirred suspension of Na[Fe(CO)2Cp] (1a)
3248 Eur. J. Inorg. Chem. 2002, 3242Ϫ3252

Synthesis, Structural Characterization and Reactivity of (Ferriomethyl)silanols
FULL PAPER
(1329 mg, 6.65 mmol) in cyclohexane (40 mL) was treated with pentane): ν˜ ϭ 3698 (w, OH), 2000 (s, CO), 1959 cmϪ1 (vs, CO).
ClCH2Si(Me)(Ph)Cl (2b) (2157 mg, 10.51 mmol) and stirred for C10H14FeO3Si (266.15): calcd. C 45.13, H 5.30; found C 45.11, H
36 h at room temperature in the dark. The reaction mixture was 5.21.
filtered through a Celite pad and the filtrate concentrated in vacuo.
4. {[Dicarbonyl(η5-cyclopentadienyl)ferrio]methyl}methyl(phenyl)-
Excess 2b was distilled off at 90 °C (10Ϫ2 Torr) and the remaining
dark brown oil was heated to 120 °C for 3 h. After cooling to room
temperature, the mixture was suspended in n-pentane (20 mL) and
filtered off from insoluble decomposition products through a Celite
pad. The filtrate was reduced to a volume of 8 mL and 3b was
crystallized at Ϫ78 °C and dried in vacuo. Yield: 1093 mg (47%).
silanol (4b): According to 3.a) obtained from 3b (352 mg,
1.02 mmol), Et3N (219 mg, 2.16 mmol) and H2O (100 mg,
5.56 mmol) in Et2O (20 mL) after 4 h at room temperature. Yield:
247 mg (74%). Yellow-orange, crystalline solid. M.p. 60 °C. 1H
NMR: δ ϭ 7.63 (m, 2 H, H5C6Si), 7.26 (m, 3 H, H5C6Si), 4.18 (s,
5 H, H5C5), 1.28 (br. s, 1 H, HO), 0.44 (s, 3 H, H3CSi), Ϫ0.09 (d,
2JH,H ϭ 12.8 Hz, 1 H, H2C), Ϫ0.38 (d, 2JH,H ϭ 12.8 Hz, 1 H, H2C)
ppm. 13C{1H} NMR: δ ϭ 217.8 (s, CO), 217.6 (s, CO), 142.9 (s,
C-1 of C6H5), 133.5 (s, C-2, C-6 of C6H5), 129.1 (s, C-3, C-5 of
C6H5), 128.0 (s, C-4 of C6H5), 84.8 (s, C5H5), 1.8 (s, CH3), Ϫ24.9
(s, CH2) ppm. 29Si{1H} NMR: δ ϭ 11.7 (s) ppm. IR (n-pentane):
ν˜ ϭ 3682 (w, br, OH), 1995 (s, CO), 1952 cmϪ1 (vs, CO).
C15H16FeO3Si (328.23): calcd. C 54.89, H 4.91; found C 54.60, H
5.06.
1
Orange-brown, waxy solid. M.p. 55 °C. H NMR: δ ϭ 7.69 (m, 2
H, H5C6Si), 7.20 (m, 3 H, H5C6Si), 3.97 (s, 5 H, H5C5), 0.75 (s, 3
2
H, H3C), Ϫ0.02 (d, JH,H ϭ 12.9 Hz, 1 H, H2C), Ϫ0.05 ppm (d,
2JH,H ϭ 12.9 Hz, 1 H, H2C). 13C{1H} NMR: δ ϭ 216.99 (s, CO),
216.96 (s, CO), 139.7 (s, C-1 of C6H5), 133.7 (s, C-2, C-6 of C6H5),
129.9 (s, C-4 of C6H5), 128.2 (s, C-3, C-5 of C6H5), 84.8 (s, C5H5),
3.3 (s, CH3), Ϫ24.9 (s, CH2) ppm. 29Si{1H} NMR: δ ϭ 27.9 (s)
ppm. IR (n-pentane): ν˜ ϭ 1999 (s, CO), 1962 cmϪ1 (vs, CO).
C15H15ClFeO2Si (346.75): calcd. C 51.97, H 4.36; found C 51.60,
H 4.64.
5.
{[Dicarbonyl(η5-pentamethylcyclopentadienyl)ferrio]methyl}-
dimethylsilanol (4c): According to 3.a) obtained from 3c (126 mg,
0.36 mmol), Et3N (365 mg, 3.60 mmol) and H2O (200 mg,
11.1 mmol) in Et2O (20 mL) after 4 h at room temperature. Precip-
itated [Et3NH]Cl and excess H2O were removed by filtration
through Na2SO4. The filtrate was concentrated in vacuo and
treated with n-pentane (5 mL). The by-products C5Me5(OC)2FeCl
and [C5Me5(OC)2Fe]2 were crystallized at 0 °C and separated by
filtration through a Celite pad. The filtrate was reduced to 2 mL
and 6c was crystallized at Ϫ78 °C and dried in vacuo. Yield: 48 mg
2. Chloro{[dicarbonyl(η5-pentamethylcyclopentadienyl)ferrio]meth-
yl}dimethylsilane (3c): A stirred suspension of Na[Fe(CO)2C5Me5]
(1b) (1315 mg, 4.87 mmol) in cyclohexane (40 mL) was treated with
ClCH2SiMe2Cl (2a) (1087 mg, 7.60 mmol) and stirred for 20 h at
room temperature in the dark. The reaction mixture was filtered
through a Celite pad and the filtrate concentrated in vacuo. The
orange-red residue was treated with n-pentane (15 mL) and stored
at Ϫ20 °C overnight to crystallize the by-products [C5Me5-
(OC)2Fe]2 and C5Me5(OC)2FeCl. The supernatant liquid was
separated and the volume reduced in vacuo to 10 mL. Remaining
C5Me5(OC)2FeCl was crystallized at Ϫ20 °C and filtered off. The
filtrate was reduced in vacuo to 5 mL and 3c was crystallized at
Ϫ78 °C, washed twice with n-pentane (each 1 mL) at this temper-
ature and dried in vacuo. Yield: 571 mg (33%). Orange-brown,
waxy solid. M.p. 60 °C (decomp.). 1H NMR: δ ϭ 1.25 [s, 15 H,
(H3C)5C5], 0.66 (s, 6 H, H3CSi), Ϫ0.43 (s, 2 H, H2C) ppm. 13C{1H}
NMR: δ ϭ 219.5 (s, CO), 95.7 [s, C5(CH3)5], 9.1 [s, (CH3)5C5], 4.7
(s, CH3Si), Ϫ12.0 (s, CH2) ppm. 29Si NMR: δ ϭ 35.5 (non, 2JSi,H ϭ
6.7 Hz) ppm. IR (cyclohexane): ν˜ ϭ 1983 (s, CO), 1931 cmϪ1 (vs,
CO). C15H23ClFeO2Si (354.75): calcd. C 50.79, H 6.53; found C
50.51, H 6.30.
1
(40%). Yellow-orange solid. M.p. 89 °C (decomp.). H NMR: δ ϭ
1.35 [s, 15 H, (H3C)5C5], 0.92 (br. s, 1 H, HO), 0.40 (s, 6 H, H3CSi),
Ϫ0.62 (s, 2 H, H2C) ppm. 13C{1H} NMR: δ ϭ 220.1 (s, CO), 95.2
[s, C5(CH3)5], 9.2 [s, (CH3)5C5], 3.2 (s, CH3Si), Ϫ12.4 (s, CH2) ppm.
29Si{1H} NMR: δ ϭ 21.1 (s) ppm. IR (n-pentane): ν˜ ϭ 3703 (w,
OH), 1988 (s, CO), 1936 cmϪ1 (vs, CO). C15H24FeO3Si (336.29):
calcd. C 53.57, H 7.19; found C 53.82, H 7.05.
6. 1,3-Bis{[dicarbonyl(η5-cyclopentadienyl)ferrio]methyl}-1,1,3,3-te-
tramethyldisiloxane (5). a) Self Condensation of Cp(OC)2FeCH2Si-
Me2OH (4a): In an NMR sample tube 4a (20 mg, 0.08 mmol) was
dissolved in C6D6 (0.6 mL). After 30 d at room temperature, 5 was
formed in 33% yield as determined by 1H NMR spectroscopy. b)
Reaction of Cp(OC)2FeCH2SiMe2OH (4a) with Cp(OC)2FeCH2Si-
Me2Cl (3a): 3a (103 mg, 0.48 mmol) in Et2O (20 mL) was added
dropwise to a stirred solution of 4a (108 mg, 0.41 mmol) in Et2O
(20 mL). After stirring for 3 d in the dark at room temperature, all
volatiles were removed in vacuo. The residue was suspended in n-
pentane (15 mL) and filtered through a Celite pad. The volume of
the filtrate was reduced in vacuo to 3 mL and 5 crystallized at Ϫ78
°C. Solid 5 melts upon warming to room temperature. Yield:
163 mg (77%). Orange-brown oil. 1H NMR: δ ϭ 4.24 (s, 10 H,
H5C5), 0.36 (s, 12 H, H3C), Ϫ0.25 (s, 4 H, H2C) ppm. 13C{1H}
NMR: δ ϭ 218.0 (s, CO), 84.9 (s, C5H5), 4.0 (s, CH3), Ϫ22.4 (s,
CH2) ppm. 29Si{1H} NMR: δ ϭ 12.8 (s) ppm. IR (n-pentane): ν˜ ϭ
2003 (s, CO), 1961 cmϪ1 (vs, CO). C20H26Fe2O5Si2 (514.29): calcd.
C 46.71, H 5.09; found C 46.37, H 5.32.
3.
{[Dicarbonyl(η5-cyclopentadienyl)ferrio]methyl}dimethylsilanol
(4a). a) Hydrolysis of Cp(OC)2FeCH2SiMe2Cl (3a) in the Presence
of Et3N: A stirred solution of 3a (237 mg, 0.83 mmol) in Et2O (30
mL) was treated with Et3N (730 mg, 7.21 mmol) and H2O (100 mg,
5.55 mmol). After addition, stirring was continued for 2 h at room
temperature. Precipitated [Et3NH]Cl and excess H2O were removed
by filtration through Na2SO4. The filtrate was concentrated in va-
cuo, leaving yellow-brown oily 4a, which was crystallized from n-
pentane (3 mL) at Ϫ78 °C and dried in vacuo. Yield: 197 mg (89%).
b) Oxygenation of Cp(OC)2FeCH2SiMe2H (3d) with Dimethyldioxi-
rane: A stirred solution of 3d (238 mg, 0.95 mmol) in acetone (10
mL) was treated dropwise at Ϫ78 °C with a solution of dimethyldi-
oxirane (1.22 mmol,16 mL, 0.076 ) in acetone. After addition, the
reaction mixture was stirred for 1 h at this temperature and an ad-
ditional 1 h at room temperature. All volatiles were removed in va-
7. 1-{[Dicarbonyl(η5-cyclopentadienyl)ferrio]methyl}-1,1,3,3-tetra-
cuo, leaving brown oily 4a, which was crystallized from n-pentane methyldisiloxane (6a): According to 6.b) obtained from 4a (866 mg,
(3 mL) at Ϫ78 °C and dried in vacuo. Yield: 170 mg (67%). Yellow-
brown, waxy solid. M.p. 38 °C. 1H NMR: δ ϭ 4.24 (s, 5 H, H5C5),
0.95 (br. s, 1 H, HO), 0.23 (s, 6 H, H3C), Ϫ0.42 (s, 2 H, H2C) ppm.
3.26 mmol), Et3N (1186 mg, 11.50 mmol) and Me2Si(H)Cl
(694 mg, 10.26 mmol) in Et2O (60 mL) after stirring in the dark at
room temperature for 12 h. The residue was suspended in n-pent-
13C{1H} NMR: δ ϭ 218.0 (s, CO), 84.8 (s, C5H5), 3.2 (s, CH3), ane (40 mL) and filtered through a Celite pad. The filtrate was
Ϫ23.1 (s, CH2) ppm. 29Si{1H} NMR: δ ϭ 21.8 (s) ppm. IR (n-
concentrated in vacuo, leaving 6a. Yield: 900 mg (85%). Yellow-
Eur. J. Inorg. Chem. 2002, 3242Ϫ3252
3249

W. Malisch, M. Hofmann, M. Nieger, W. W. Schöller, A. Sundermann
brown oil. 1H NMR: δ ϭ 5.05 (sept, 3JH,H ϭ 2.4, 1JH,Si ϭ 201.6 Hz, room temperature. Yield: 204 mg (79%). Yellow-brown oil. 1H
FULL PAPER
1 H, HSi), 4.19 (s, 5 H, H5C5), 0.28 [s, 6 H, (H3C)2SiCH2], 0.22 [d,
NMR: δ ϭ 4.21 (s, 5 H, H5C5), 0.28 [s, 6 H, (H3C)2Si], 0.18 [s, 9
3JH,H ϭ 2.4 Hz, 6 H, (H3C)2SiH], Ϫ0.39 (s, 2 H, H2C) ppm. H, (H3C)3Si], Ϫ0.36 (s, 2 H, H2C) ppm. 13C{1H} NMR: δ ϭ 217.9
13C{1H} NMR: δ ϭ 217.9 (s, CO), 84.8 (s, C5H5), 3.4 [s, (s, CO), 84.9 (s, C5H5), 3.8 [s, (CH3)2Si], 2.3 [s, (CH3)3Si], Ϫ22.5 (s,
(CH3)2SiCH2], 1.2 [s, (CH3)2SiH], Ϫ23.0 (s, CH2) ppm. 29Si{1H}
NMR: δ ϭ 15.9 (s, SiCH2Fe), Ϫ8.0 (s, SiH) ppm. IR (n-pentane):
CH2) ppm. 29Si NMR: δ ϭ 13.8 (m, SiCH2Fe), 6.2 [dec, JSi,H
ϭ
2
7.0 Hz, Si(CH3)3] ppm. IR (Et2O): ν˜ ϭ 2000 (vs, CO), 1953 cmϪ1
ν˜ ϭ 2116 (w, br, SiH), 2003 (s, CO), 1961 cmϪ1 (vs, CO). (vs, CO). C13H22FeO3Si2 (338.33): calcd. C 46.15, H 6.55; found C
C12H20FeO3Si2 (324.30): calcd. C 44.44, H 6.21; found C 44.09,
H 6.21.
46.80, H 6.63.
X-ray Crystal Structure Analyses of 4a؊c: Table 1 contains details
of the structures. The intensities were measured with a Nonius-
8.
1-{[Dicarbonyl(η5-cyclopentadienyl)ferrio]methyl}-1,1,3-trime-
˚
thyl-3-(p-tolyl)disiloxane (6b): According to 7. obtained from 4a Kappa CCD diffractometer (Mo-Kα radiation, λ ϭ 0.71073 A,
(296 mg, 1.11 mmol), Et3N (219 mg, 2.16 mmol) and (p-Tol)-
(Me)(H)SiCl (189 mg, 1.11 mmol) in Et2O (40 mL) after stirring
for 24 h in the dark at room temperature. After workup the crude
graphite monochromator) at T ϭ Ϫ150 °C. The structures were
solved by direct methods (Patterson methods)[80] (SHELXS-97)
and refined by least-squares methods based on F2 with all meas-
ured reflections (SHELXL-97) (full-matrix least-squares on F2,[81]).
product was dried for 6 h at 5 ϫ 10Ϫ5 Torr. Yield: 338 mg (76%).
3
Brown oil. 1H NMR: δ ϭ 7.63 (d, JH,H ϭ 7.4 Hz, 2 H, H4C6), Non-hydrogen atoms were refined anisotropically, H atoms local-
3
7.08 (d, 3JH,H ϭ 7.4 Hz, 2 H, H4C6), 5.47 (q, JH,H ϭ 2.8, 1JH,Si ϭ ized by difference electron density and refined using a ‘‘riding’’
206.4 Hz, 1 H, HSi), 4.16 (s, 5 H, H5C5), 2.10 (s, 3 H, H3CC6H4), model [H(O) free]. An empirical absorption correction was applied.
0.47 (d, 3JH,H ϭ 2.8 Hz, 3 H, H3CSiH), 0.31 [s, 6 H, (H3C)2SiCH2],
Ϫ0.35 (s, 2 H, H2C) ppm. 13C{1H} NMR: δ ϭ 217.8 (s, CO), 139.8
CCDC-115086 (4a), -148145 (4b) and -156552 (4c) contain the sup-
plementary crystallographic data for this paper. These data can be
(s, C-1 of C6H4), 135.0 (s, C-4 of C6H4), 134.0 (s, C-2, C-6 of C6H4), obtained free of charge at www.ccdc.cam.ac.uk/conts/retriev-
129.1 (s, C-3, C-5 of C6H4), 84.8 (s, C5H5), 21.5 (s, CH3C6H4), 3.5 ing.html or from the Cambridge Crystallographic Data Centre, 12
[s, (CH3)2SiCH2], 0.1 (s, CH3SiH), Ϫ23.1 (s, CH2) ppm. 29Si NMR: Union Road, Cambridge CB2 1EZ, UK [Fax: (internat.) ϩ 44-
1
2
δ ϭ 17.0 (m, SiCH2Fe), Ϫ14.6 (dsext, JSi,H ϭ 206.4, JSi,H
ϭ
1223/336-033; E-mail: deposit@ccdc.cam.ac.uk].
6.4 Hz, SiH) ppm. IR (n-pentane): ν˜ ϭ 2119 (w, br, SiH), 2002 (s,
CO), 1960 cmϪ1 (vs, CO). C18H24FeO3Si2 (400.41): calcd. C 53.99,
H 6.04; found C 54.00, H 5.97.
Acknowledgments
We gratefully acknowledge financial support from the Deutsche
9. 3-{[Dicarbonyl(η5-cyclopentadienyl)ferrio]methyl}-1,1,1,3,3-pen-
Forschungsgemeinschaft (Schwerpunktprogramm ‘‘Spezifische
tamethyldisiloxane (6c): According to 7. obtained from 4a (213 mg, Phänomene in der Siliciumchemie’’) as well as from the Fonds der
0.80 mmol), Et3N (219 mg, 2.16 mmol) and Me3SiCl (257 mg,
2.37 mmol) in Et2O (30 mL) after stirring for 24 h in the dark at
Chemischen Industrie. M. N. wants to thank the DAAD for finan-
cial support.
Table 1. Data for the crystal structure analyses
4a
4b
4c
Empirical formula
Formula mass
Crystal system
Space group
C10H14FeO3Si
266.15
C15H16FeO3Si
328.22
tetragonal
I41/a (no. 88)
C15H24FeO3Si
336.28
monoclinic
C2/c (no. 15)
triclinic
¯
P1 (no. 2)
Unit cell
˚
a [A]
8.0351(4)
11.4028(4)
13.9508(6)
75.637(2)
79.190(2)
76.894(2)
1194.27(9)
4
22.0578(10)
22.0578(10)
12.4151(6)
90
90
90
6040.5(5)
16
1.444
1.081
2720
27.2245(2)
13.8293(1)
9.3090(1)
90
101.394(1)
90
3435.73(5)
8
1.300
˚
b [A]
˚
c [A]
α [°]
β [°]
γ [°]
3
˚
Volume [A ]
Z
Calcd. density [g/cm3]
1.480
1.347
552
µ [mmϪ1
F(000)
]
0.951
1424
Crystal size [mm]
θ range [°]
0.30 ϫ 0.25 ϫ 0.09
2.85/28.30
Ϫ10 Յ h Յ 9
Ϫ14 Յ k Յ 14
Ϫ17 Յ l Յ 14
11445
5413
277, 4
0.0275
0.40 ϫ 0.35 ϫ 0.30
1.85/26.35
Ϫ27 Յ h Յ 27
Ϫ25 Յ k Յ 25
Ϫ12 Յ l Յ 15
13115
3035
184, 1
0.0299
0.35 ϫ 0.20 ϫ 0.10
1.66/25.00
Ϫ32 Յ h Յ 32
Ϫ16 Յ k Յ 16
Ϫ11 Յ l Յ 11
34665
3020
186, 0
0.0255
Index ranges (h, k, l)
No. of reflections
No. of unique reflections
Parameters, restraints
R1 [I Ͼ 2σI]
wR2
T [K]
0.0678
123(2)
0.367/Ϫ0.353
0.0664
123(2)
0.220/Ϫ0.304
0.0690
123(2)
0.282/Ϫ0.268
3
˚
Max. residual electron density [e/A ]
3250
Eur. J. Inorg. Chem. 2002, 3242Ϫ3252

Synthesis, Structural Characterization and Reactivity of (Ferriomethyl)silanols
FULL PAPER
[33]
R. Goikhman, M. Aizenberg, H.-B. Kraatz, D. Milstein, J. Am.
Chem. Soc. 1995, 117, 5865Ϫ5866.
[1]
[2]
W. Malisch, M. Hofmann, G. Kaupp, H. Käb, J. Reising, Eur.
J. Inorg. Chem. 2002, 3235Ϫ3241, preceding paper.
P. Panster, S. Wieland in Applied Homogeneous Catalysis with
Organometallic Compounds (Eds.: B. Cornils, W. A. Herrm-
ann), VCH, Weinheim, 1996, p. 605.
Y. Iwasawa, Tailored Metal Catalysts, Reidel, Dordrecht, 1986.
F. R. Hartley, Supported Metal Complexes, Reidel, Dord-
recht, 1985.
Y. I. Yermakov, B. N. Kuznetsov, V. A. Zakharov, Catalysis by
Supported Complexes, Elsevier, Amsterdam, 1981.
R. Siefken, M. Teichert, D. Chakraborty, H. W. Roesky, Or-
ganometallics 1999, 18, 2321Ϫ2325.
P. Jutzi, M. Schneider, H.-G. Stammler, B. Neumann, Organo-
metallics 1997, 16, 5377Ϫ5380.
R. Murugavel, V. Chandrasekhar, H. W. Roesky, Acc. Chem.
Res. 1996, 29, 183Ϫ189.
N. Winkhofer, A. Voigt, H. Dorn, H. W. Roesky, A. Steiner, D.
Stalke, A. Reller, Angew. Chem. 1994, 106, 1414Ϫ1416; Angew.
Chem. Int. Ed. Engl. 1994, 33, 1352Ϫ1354.
N. Winkhofer, H. W. Roesky, M. Noltemeyer, W. T. Robinson,
Angew. Chem. 1992, 104, 670Ϫ671; Angew. Chem. Int. Ed.
Engl. 1992, 31, 599Ϫ601.
H. C. L. Abbenhuis, Chem. Eur. J. 2000, 6, 25Ϫ32.
F. J. Feher, T. A. Budzichowski, Polyhedron 1995, 14,
3239Ϫ3253.
[34]
[35]
[36]
[37]
[38]
[39]
[40]
S. H. A. Petri, D. Eikenberg, B. Neumann, H.-G. Stammler, P.
Jutzi, Organometallics 1999, 18, 2615Ϫ2618.
W. Adam, R. Mello, R. Curci, Angew. Chem. 1990, 102,
916Ϫ917; Angew. Chem. Int. Ed. Engl. 1990, 29, 890Ϫ891.
W. Adam, A. K. Smerz, Bull. Soc. Chim. Belg. 1996, 105,
581Ϫ599.
W. Adam, J. Bialas, L. Hadajiarapolou, Chem. Ber. 1991, 124,
2377.
W. Malisch, M. Hofmann, M. Vögler, H. Jehle, D. Schumacher,
unpublished results.
[3]
[4]
[5]
[6]
[7]
[8]
[9]
W. Mowat, G. Wilkinson, J. Chem. Soc., Dalton Trans. 1973,
1120Ϫ1124.
P. J. Davidson, M. F. Lappert, R. Pearce, Acc. Chem. Res. 1974,
7, 209Ϫ217.
R. R. Schrock, G. W. Parshall, Chem. Rev. 1976, 76, 243Ϫ268.
K. H. Pannell, J. Organomet. Chem. 1970, 21, P17ϪP18.
J. E. Bulkowski, N. D. Miro, D. Sepelak, C. H. Van Dyke, J.
Organomet. Chem. 1975, 101, 267Ϫ277.
C. Windus, S. Sujishi, W. P. Giering, J. Am. Chem. Soc. 1974,
96, 1951Ϫ1952.
C. Windus, S. Sujishi, W. P. Giering, J. Organomet. Chem. 1975,
101, 279Ϫ293.
C. Lewis, M. S. Wrighton, J. Am. Chem. Soc. 1983, 105,
7768Ϫ7770.
C. L. Randolph, M. S. Wrighton, Organometallics 1987, 6,
365Ϫ371.
T. S. Koloski, P. J. Carroll, D. H. Berry, J. Am. Chem. Soc.
1990, 112, 6405Ϫ6406.
J. E. Bulkowski, R. Stacy, C. H. Van Dyke, J. Organomet.
Chem. 1975, 87, 137Ϫ143.
K. Itoh, T. Fukahori, J. Organomet. Chem. 1988, 349,
227Ϫ234.
[41]
[42]
[43]
[44]
[45]
[46]
[47]
[48]
[49]
[50]
[51]
[52]
[10]
[11]
[12]
[13]
[14]
[15]
H. C. L. Abbenhuis, S. Krijnen, R. A. van Santen, Chem. Com-
mun. 1997, 331Ϫ332.
F. J. Feher, F. Nguyen, D. Soulivong, J. W. Ziller, Chem. Com-
mun. 1999, 1705Ϫ1706.
F. J. Feher, R. Terroba, R.-Z. Jin, Chem. Commun. 1999,
2513Ϫ2514.
[16]
[17]
G. Calzaferri, Nachr. Chem. Tech. Lab. 1992, 40, 1106Ϫ1114.
F. T. Edelmann, Angew. Chem. 1992, 104, 600Ϫ601; Angew.
Chem. Int. Ed. Engl. 1992, 31, 586Ϫ587.
W. A. Herrmann, R. Anwander, V. Dufaud, W. Scherer, Angew.
Chem. 1994, 106, 1338Ϫ1340; Angew. Chem. Int. Ed. Engl.
1994, 33, 1285Ϫ1286.
W. Malisch, H. Jehle, C. Mitchel, W. Adam, J. Organomet.
Chem. 1998, 566, 259Ϫ262.
W. Malisch, R. Lankat, S. Schmitzer, J. Reising, Inorg. Chem.
1995, 34, 5701Ϫ5702.
W. Malisch, R. Lankat, O. Fey, J. Reising, S. Schmitzer, J.
Chem. Soc., Chem. Commun. 1995, 1917Ϫ1919.
W. Malisch, S. Schmitzer, R. Lankat, M. Neumayer, F. Prechtl,
W. Adam, Chem. Ber. 1995, 128, 1251Ϫ1255.
W. Malisch, S. Möller, R. Lankat, J. Reising, S. Schmitzer, O.
Fey, in Organosilicon Chemistry II: From Molecules to Mat-
erials (Eds.: N. Auner, J. Weis), VCH, Weinheim, 1996, p. 575.
W. Malisch, S. Schmitzer, G. Kaupp, K. Hindahl, H. Käb, U.
Wachtler, in Organosilicon Chemistry: From Molecules to Mat-
erials, vol. 1 (Eds.: N. Auner, J. Weis), VCH, Weinheim, 1994,
p. 185.
W. Malisch, H. Jehle, S. Möller, C.-S. Möller, W. Adam, Eur.
J. Inorg. Chem. 1998, 1585Ϫ1587.
S. Möller, O. Fey, W. Malisch, W. Seelbach, J. Organomet.
Chem. 1996, 507, 239Ϫ244.
C. S. Cundy, M. F. Lappert, C. K. Yuen, J. Chem. Soc., Dalton
Trans. 1978, 427Ϫ433.
C. E. F. Rickard, W. R. Roper, D. M. Salter, L. J. Wright, J.
Am. Chem. Soc. 1992, 114, 9682Ϫ9683.
H. Handwerker, C. Leis, R. Probst, P. Bissinger, A. Grohmann,
P. Kiprof, E. Herdtweck, J. Bluemel, N. Auner, C. Zybill, Or-
ganometallics 1993, 12, 2162Ϫ2176.
A. D. Horton, A. G. Orpen, Organometallics 1992, 11,
1193Ϫ1201.
M. Enders, J. Fink, V. Maillant, H. Pritzkow, Z. Anorg. Allg.
[18]
Chem. 2001, 627, 2281Ϫ2288.
[53]
[54]
3a was first synthesized by Giering et al.[44,45]
L. Pope, P. Sommerville, M. Laing, J. Organomet. Chem. 1976,
112, 309Ϫ324.
[19]
[20]
[21]
[22]
[23]
[55]
[56]
G.-H. Lee, S.-M. Peng, S.-F. Lush, D. Mu, R.-S. Liu, Organo-
metallics 1988, 7, 1155Ϫ1161.
M. Akita, A. Kondoh, Y. Moro-oka, J. Chem. Soc., Dalton
Trans. 1989, 1083Ϫ1087.
H. A. Bent, Chem. Rev. 1961, 61, 275Ϫ311.
R. L. Scholl, G. E. Maciel, W. K. Musker, J. Am. Chem. Soc.
1972, 94, 6376Ϫ6385.
S. G. Davies, I. M. Dordor-Hedgecock, K. H. Sutton, M.
Whittaker, J. Am. Chem. Soc. 1987, 109, 5711Ϫ5719.
K. H. Pannell, T. Kobayashi, F. Cervantes-Lee, Y. Zhang, Or-
ganometallics 2000, 19, 1Ϫ3.
Y. Zhang, F. Cervantes-Lee, K. H. Pannell, J. Am. Chem. Soc.
2000, 122, 8327Ϫ8328.
[57]
[58]
[59]
[60]
[61]
[62]
[63]
[64]
[24]
[25]
[26]
[27]
[28]
[29]
H. Puff, K. Braun, H. Reuter, J. Organomet. Chem. 1991,
409, 119Ϫ129.
Z. H. Aiube, N. H. Buttrus, C. Eaborn, P. B. Hitchcock, J. A.
Zora, J. Organomet. Chem. 1985, 292, 177Ϫ188.
P. D. Lickiss, N. L. Clipston, D. W. H. Rankin, H. E. Robert-
son, J. Mol. Struct. 1995, 344, 111Ϫ116.
P. D. Lickiss, Adv. Inorg. Chem. 1995, 42, 147Ϫ262.
D. Braga, F. Grepioni, K. Biradha, V. R. Pedireddi, G. R. Desi-
raju, J. Am. Chem. Soc. 1995, 117, 3156Ϫ3166.
D. Braga, F. Grepioni, Acc. Chem. Res. 1997, 30, 81Ϫ87.
The difference electron density determination [after refinement
taking H(C) into account, which was also localized by differ-
ence electron density determination and refined using a riding
model] shows two difference peaks in a reasonable OϪH dis-
tance, also with reasonable intermolecular HϪO distances for-
ming hydrogen bonds (to SiϪOH in two different molecules).
[65]
[66]
[67]
[68]
[30]
[31]
[32]
L. S. Chang, M. P. Johnson, M. J. Fink, Organometallics 1991,
10, 1219Ϫ1221.
W. Adam, U. Azzena, F. Prechtl, K. Hindahl, W. Malisch,
Chem. Ber. 1992, 125, 1409Ϫ1411.
W. Malisch, K. Hindahl, H. Käb, J. Reising, W. Adam, F.
Prechtl, Chem. Ber. 1995, 128, 963Ϫ965.
Eur. J. Inorg. Chem. 2002, 3242Ϫ3252
3251

W. Malisch, M. Hofmann, M. Nieger, W. W. Schöller, A. Sundermann
FULL PAPER
[71]
There is a significant gap between those two peaks and the
remaining peaks in the difference density map. Using HFIX
87, HFIX 147 and HTAB in the SHELXL-97 refinement two
possible H(O) positions, very close to the low localized density
peaks, are indicated. This all suggests a disorder (50:50) of the
SiϪOH group with ‘‘flipping’’ hydrogen bond pattern. In addi-
tion, data are collected at 123 K and the quality is ‘‘not so
bad’’, which even improves the possibility of localization of
disordered H atoms.
W. J. Stevens, M. Krauss, H. Basch, P. Jasien, Can. J. Chem.
1992, 70, 612Ϫ630.
T. Cundari, W. J. Stevens, J. Chem. Phys. 1993, 98, 5555Ϫ5565.
The d-orbital exponents for the polarization functions are: Si
0.395, C. 0.800, O. 0.800.
Gradient-corrected density functional of Perdew: J. P. Perdew,
Phys. Rev. 1986, B33, 8822Ϫ8824.
A. E. Reed, L. A. Curtiss, F. Weinhold, Chem. Rev. 1988, 88,
899Ϫ926. E. D. Glendening, A. E. Reed, J. E. Carpenter, F.
Weinhold, NBO, version 3.1.
H. Marsmann, in NMR Ϫ Basic Principles and Progress, vol.
17 (Eds.: P. Diehl, E. Fluck, R. Kosfeld), Springer-Verlag, Ber-
lin, Heidelberg, New York, 1981, p. 151.
T. S. Piper, G. Wilkinson, J. Inorg. Nucl. Chem. 1956, 3,
104Ϫ124.
T. Blackmore, M. I. Bruce, F. G. A. Stone, J. Chem. Soc. A
1968, 2158Ϫ2162.
[72]
[73]
[74]
[69]
All quantum chemical calculations were performed with the
Gaussian set of programs. M. J. Frisch, G. W. Trucks, H. B.
Schlege, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, V. G.
Zakrzewski, J. A. Montgomery, R. E. Stratmann, J. C. Burant,
S. Dapprich, J. M. Millam, A. D. Daniels, K. N. Kudin, M. C.
Strain, O. Farkas, J. Tomasi, V. Barone, M. Cossi, R. Cammi,
B. Mennucci, C. Pomelli, C. Adamo, S. Clifford, J. Ochterski,
G. A. Petersson, P. Y. Ayala, Q. Cui, K. Morokuma, D. K.
Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J.
Cioslowski, J. V. Ortiz, B. B. Stefanov, G. Liu, A. Liashenko,
P. Piskorz, I. Komaromi, R. Gomperts, R. L. Martin, D. J.
Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanyakkara,
C. Gonzalez, M. Challacombe, P. M. W. Gill, B. G. Johnson,
W. Chen, M. W. Wong, J. L. Andres, M. Head-Gordon, E. S.
Replogle, J. A. Pople, Gaussian 98 (Revision A.1), Gaussian
Inc., Pittsburgh PA, 1998.
[75]
[76]
[77]
[78]
N. Auner, J. Grobe, J. Organomet. Chem. 1980, 188, 151Ϫ177.
A. Kunai, E. Toyoda, T. Kawakami, M. Ishikawa, Organomet-
allics 1992, 11, 2899Ϫ2903.
SHELXS-97: G. M. Sheldrick, Acta Crystallogr., Sect. A 1990,
46, 467Ϫ473.
G. M. Sheldrick, SHELXL-97, University of Göttingen, 1997.
[79]
[80]
[81]
[70]
Basis set SBK(d): W. J. Stevens, H. Basch, M. Krauss, J. Chem.
Received March 15, 2002
[I02131]
Phys. 1984, 81, 6026Ϫ6033.
3252
Eur. J. Inorg. Chem. 2002, 3242Ϫ3252