Highly selective synthesis and structural characterization of bis(silyl)-[3]-ferrocenophane derivatives

Article abstract of DOI:10.1021/om050194x

Bis(silyl)-[3]-ferrocenophanes have been easily prepared via ring-closing silylative coupling of 1,1′-bis(vinylsilyl)ferrocenes catalyzed by ruthenium hydride complexes. Dimethylvinylsilyl derivative 1 reacts under optimum conditions to give regioselectively and quantitatively disilacyclic product containing an exo-methylene (3) bond between two silicon atoms. The reaction with (diphenylvinylsilyl)ferrocene (2) permits stereoselective synthesis of the product with a cis-vinylene (4) bond between the silicon atoms. The structures of both products, which cannot be synthesized via a ring-closing metathesis procedure, have been confirmed using NMR and X-ray crystal structure methods.

Full text of DOI:10.1021/om050194x

Organometallics 2005, 24, 3731-3736
3731
Highly Selective Synthesis and Structural
Characterization of Bis(silyl)-[3]-ferrocenophane
Derivatives
Mariusz Majchrzak, Bogdan Marciniec,* Maciej Kubicki, and Adam Pawełczyk
Department of Organometallic Chemistry, Faculty of Chemistry, Adam Mickiewicz University,
Grunwaldzka 6, 60-780 Poznan, Poland
Received March 15, 2005
Bis(silyl)-[3]-ferrocenophanes have been easily prepared via ring-closing silylative coupling
of 1,1′-bis(vinylsilyl)ferrocenes catalyzed by ruthenium hydride complexes. Dimethylvinylsilyl
derivative 1 reacts under optimum conditions to give regioselectively and quantitatively
disilacyclic product containing an exo-methylene (3) bond between two silicon atoms. The
reaction with (diphenylvinylsilyl)ferrocene (2) permits stereoselective synthesis of the product
with a cis-vinylene (4) bond between the silicon atoms. The structures of both products,
which cannot be synthesized via a ring-closing metathesis procedure, have been confirmed
using NMR and X-ray crystal structure methods.
Scheme 1. Mechanism of Silylative Coupling
Reaction
Introduction
The discovery of ferrocene dates back to the 1950s,
and since then it has been an interesting research
material for scientists worldwide.1 Ferrocene and its
various derivatives have found application in many
fields such as synthetic organic chemistry, materials
science, and catalysis.2 Ferrocene has been found to be
easily functionalized. This feature is particularly evident
in the preparation of bridged ferrocenessthe so-called
“ring system”sferrocenophanes.3 The bridges of ferro-
cenophanes contain a few carbon atoms (for review see
ref 4) or heteroatom combinations such as group 13 (B),
group 14 (Si, the first example of A: ERx ) SiPh2,6 Ge,
Sn), group 15 (P, As, N7), and group 16 (S, Se) (A) (ref
5 and references within). The compounds of this type
are usually used for syntheses of inorganic polymers via
ring-opening polymerization (ROP).
1,3-diene in the presence of palladium complex [Pd-
(PPh3)4], giving cyclic unsaturated organometallic ring
systems.8
An alternative way to get this type of silicon com-
pounds is the reaction of silylative coupling of vinyl-
silanes in the presence of transition metal complexes
(e.g., ruthenium and rhodium) containing or generating
[M]-H and [M]-Si bonds. The silylative homo-coupling
reaction of monovinyl organosilicon compounds proceeds
through cleavage of the dC-Si bond of the vinyl-
substituted silicon compounds and the activation of the
dC-H bond of the second vinylsilane molecules.9 The
mechanism of this reaction (see Scheme 1) involving
â-silyl elimination and insertion of a CdC double bond
into the resulting [M-Si] bond has been proved by
insertion of ethylene and vinylsilane into [M-Si] (where
M ) Ru, Rh) bonds as well as by a series of elaborate
In contrast, the [2]-ferrocenophane (B) containing a
disilane bridge which cannot be applied to ROP is used
as a monomer in insertion reactions of acetylenes and
* Corresponding author. Tel: (+48)-61-8291-366. Fax: (+48)-61-
8291-508. E-mail: marcinb@amu.edu.pl.
(1) Kealy, T. J.; Pouson, P. L. Nature 1951, 168, 1039.
(2) (a) Ferrocene, Homogeneous Catalysis-Organic Synthesis-Materi-
als Science; Togni, A., Hayasi, T., Eds.; VCH: New York, 1995. (b)
Matallocenes, Togni, A., Helterman, R. L., Eds.; Wiley-VCH: Wein-
heim, Germany, 1998.
(3) (a) Plesske, K. Angew. Chem., Int. Ed. Engl. 1962, 1, 312; Angew.
Chem., Int. Ed. Engl. 1962, 1, 394. (b) Bublitz, D. E.; Reinehart, K. L.,
Jr. Org. React. 1967, 2, 231.
(4) Heo, R. W.; Lee, T. R. J. Organomet. Chem. 1999, 578, 31-42.
(5) Hudson, R. D. A. J. Organomet. Chem. 2001, 637-639, 47-69.
(6) Osborne, A. G.; Whiteley, R. H. J. Organomet. Chem. 1975, 101,
C27.
(7) Yamaguchi, I.; Sakano, T.; Ishii, H.; Osakada, K.; Yamamoto,
T. J. Organomet. Chem. 1999, 584, 213.
(8) Finckh, W.; Tang, B.-Z.; Lough, A.; Manners, I. Organometallics
1992, 11, 2904.
(9) (a) Marciniec, B.; Pietraszuk, C. Curr. Org. Chem. 2003, 7, 691-
735. (b) Marciniec, B.; Pietraszuk, C. Metathesis of Silicon-Containing
Olefins; Grubbs, R. H., Ed.; Handbook of Metathesis, Vol. 2; Wiley-
VCH: New York, 2003. (c) Marciniec, B. Appl. Organomet. Chem. 2000,
14, 527-538; Mol. Cryst. Liq. Cryst. 2000, 353, 173-182.
10.1021/om050194x CCC: $30.25 © 2005 American Chemical Society
Publication on Web 06/14/2005

3732 Organometallics, Vol. 24, No. 15, 2005
Majchrzak et al.
Scheme 2
Scheme 4
Scheme 3
Table 1. Effect of Catalyst (I-III) on the
Conversion of 1,1′-Bis(vinylsilyl)ferrocenes (1, 2)
and Yield of Products 3 and 4a
monomer
(group)
amount of
conversion of
monomer (%)c
yield
(%)d
[Ru]
catalyst (mol %)b
1e (Me)
I
0.1
0.1
0.1
1
>99
>99
>99
87
99
99
99
87
92
89
II
III
I
2f (Ph)
mass spectroscopic studies with deuterated styrene and
vinylsilanes.10
II
III
1
92
1
89
The evidence for the non-metallacarbene mechanism
of monovinylsilane transformation has been reported,10
but it can be generalized for dimerization of divinyl-
substituted silanes, siloxanes, and silazanes, leading
subsequently to competitive linear oligomerization and
ring-closing silylative coupling (Scheme 2).
The unique feature of the silylative coupling reaction
distinguishing it from cross-metathesis is the formation
of a 1,1-bis(silyl)ethene fragment under given condi-
tions.10b,11 Recently, we have reported a new facile and
efficient silylative coupling cyclization of 1,2-bis(di-
methylvinylsiloxy)ethane12a and of N,N′-dimethyl-N,N′-
bis(dimethylvinylsilyl)ethane,12b giving cyclic products,
subsequently used for regioselective synthesis of 1,1-
bis(silyl)ethenes.
a The selectivity of the reaction was over 99%. b Calculated to
monomer. c,d Calculated by GC and NMR. e t ) 5 h, toluene 1 M.
f t ) 18 h, toluene 0.25 M; T ) 110 °C. (1) [(ViSiMe2)2Fc], (2)
[(ViSiPh2)2Fc] where Fc ) [Fe(C5H4)2].
silylative coupling cyclization reaction catalyzed by
ruthenium(II) complexes was analyzed. Several catalytic
tests were performed in order to establish the most
favorable conditions for effective cyclization in the
presence of various catalysts: [RuH(Cl)(CO)(PPh3)3] (I),
[RuH(Cl)(CO)(PCy3)2] (II), [Ru(SiMe3)(Cl)(CO)(PPh3)2]
(III). In this case catalytic screenings were performed
using the model processes of 1 and 2 (Scheme 4) to
measure substrate conversions, selectivity, and the yield
of 3 and 4 by GC and GC-MS methods.
Therefore, the aim of the paper is to extend this
reaction to the synthesis of novel cyclo-ferrocene-silicon
compounds with the silicon-(exo-methylene or cis-vi-
nylene)-silicon bridged structure by the respective reac-
tion of bis(vinylsilyl)ferrocenyl derivatives 1 and 2.
The results are collected in Table 1.
The preliminary study (see Table 1) allowed us to
optimize highly stereoselective synthesis of cyclo-bis-
(silyl)ferrocenyl compounds. Depending on the groups
substituted at the silicon atom, the conversions were
99% for substrate 1 and 87-92% for substrate 2. In both
cases, complex II was the most active and efficient as a
catalyst in the intramolecular coupling reaction. This
process successfully proceeded only in solvent. In par-
ticular, for the synthesis of product 4, the correct
concentration of substrate 2 in toluene was very impor-
tant for conversion of 2 and the reaction progress.
Results and Discussion
The synthesis of substrates was performed in “one
pot” (without intermediate isolation). The lithiation of
ferrocene can be conducted selectively to give dilithio-
ferrocene (using n-BuLi in hexane in the presence of
TMEDA), according to Scheme 3:
Application of this catalytic system for silylative
coupling cyclization of 1 and 2 gave exclusively disila-
cyclic products containing an exo-methylene or cis-
vinylene bond between two silicon atoms. The structures
of both cyclo-bis(silyl)ferrocenyl derivatives (3 and 4)
were straightforwardly determined by 1H, 13C, and 29Si
NMR, DEPT spectra, and X-ray crystal structure analy-
sis. Moreover, the analysis of mass products using FAB-
MS, HR-MS, and elemental analysis additionally con-
firmed their cyclic structures.
For example, a comparison of the carbon spectrum
with a fragment of DEPT spectrum (all protonated
carbons) of product 3 revealed the existence of a
quaternary carbon atom assigned to the signal at 156.29
ppm (Cb) and carbon atom (dCH2, Ca, at 138.62 ppm)
directly terminating the exo-bond (Figure 1).
Starting from dilithio-ferrocene, bis(vinylsilyl)ferro-
cenyl derivatives 1 and 2 were obtained with good yields
from 60% to 75%. The products-substrates were char-
acterized by standard NMR methods.
At the subsequent stage of our experiment, the
reactivity of the above-mentioned compounds in the
(10) (a) Wakatsuki, Y.; Yamazaki, H.; Nakano, N.; Yamamoto, Y.
J. Chem. Soc., Chem. Commun. 1991, 703. (b) Marciniec, B.; Pietras-
zuk, C. J. Chem. Soc., Chem. Commun. 1995, 2003-2004. Organome-
tallics 1997, 16, 4320.
(11) (a) Marciniec, B.; Lewandowski, M. Tetrahedron Lett. 1997, 36,
3777-3780. (b) Mise, T.; Takaguchi, Y.; Umem, T.; Shimizu, S.;
Wakatsuki, Y. Chem. Commun. 1998, 699. (c) Marciniec, B.; Lewan-
dowski, M.; Bijpost, E.; Malecka, E.; Kubicki, M.; Walczuk-Guœciora,
E. Organometallics 1999, 20, 3968.
(12) (a) Pawluc´, P.; Marciniec, B.; Hreczycho, G.; Gaczewska, B.;
Itami, Y. J. Org. Chem. 2005, 70, 370-372. (b) Pawluc´, P.; Hreczycho,
G.; Marciniec, B. Synlett 2005, 7, 1105-1108.

Bis(silyl)-[3]-ferrocenophane Derivatives
Organometallics, Vol. 24, No. 15, 2005 3733
Figure 1. 13C NMR and fragment of DEPT spectra of product 3.
Figure 2. 13C NMR spectra of product 4.
Cyclic compound 3 was obtained according to the
reaction mechanism presented in the Introduction. The
structure of 4 was also confirmed (Figure 2). In this
compound only a cis-fragment was observed.
The characteristic signal assigned to vinylene-carbon
atoms was identified at 149.24 ppm (-HCdCH-, Ca).
The steric effect of phenyl groups at silicon atoms led
to such a product formation.
It is worth emphasizing that both processes give
stereo- and/or regioselectively cyclo-bis(silyl)ferroceno-
phanes 3 and 4, respectively, and with no linear
products observed. Apparently, the intramolecular cy-
clization of monomers 1 and 2 under the conditions
applied is much faster than the silylative coupling
polycondensation.
The Structures of Both Bis(silyl)ferrocenophanes
(3 and 4) Were Solved by the X-ray Method.
Thermal ellipsoid representations of molecules 3a and
4a are shown in Figures 3 and 4, respectively. The
overall conformations of both molecules differ signifi-
cantly. In 3 both Cp rings and C-Si bonds are in almost
ideal eclipsed disposition and the angle between two
C(Cp)-Si vectors is 6.9° (Figure 3b), while in 4, probably
due to more bulky phenyl substituents and a more
flexible CdC bridge, the conformation is closer to a
staggered one with the angle between C-Si bonds of
46.3° (Figure 4b). A similar arrangement of the rings
and C-Si bonds was observed in the related com-
pounds: in siloxane-bridged ferrocenophanes the short
Si-O-Si bridge enforced an almost eclipsed conforma-
tion and the angles between C-Si bonds were smaller
for the tetramethyl derivative (0.6°, 5.2°, and 2.1° for
three symmetry-independent molecules) than in the
tetraphenyl one (13.6°).13 Similarly, in (Z)-(1,1,4,4-
tetramethyl-1,4-disila)ethane)-[3]-ferrocenophane, the

3734 Organometallics, Vol. 24, No. 15, 2005
Majchrzak et al.
Figure 3. (a) Anisotropic ellipsoid representation of complex 3. The ellipsoids are drawn at the 50% probability level;
hydrogen atoms are depicted as spheres with arbitrary radii. (b) View perpendicular to the Cp plane.
Figure 4. (a) Anisotropic ellipsoid representation of complex 4. Ellipsoids are drawn at the 33% probability level; hydrogen
atoms are depicted as spheres with arbitrary radii. (b) View perpendicular to the Cp plane.
tetramethyl analogue of 4, the angle between C-Si
bonds is 15.0°,14 much smaller than in 4.
atoms in the cyclic compound can be synthesized via
highly selective and efficient ring-closing silylative
coupling of bis(vinylsilyl)ferrocenyl derivatives, cata-
lyzed by ruthenium hydride complexes. While the vi-
nylmethyl-substituted silylferrocene undergoes intramo-
lecular coupling, yielding regioselectively cyclo-ferro-
cenophane with exo-methylene, the vinylphenyl-substi-
tuted silylferrocene gives stereoselectively cyclo-ferro-
cenophane with a cis-vinylene group between two silicon
atoms. 1H, 13C, and 29Si DEPT spectra and X-ray crystal
structure analysis confirm the cyclic structure of the
products that cannot be synthesized via the ring-closing
metathesis procedure.
Bond length and angle patterns in both compounds
are typical: mean values of the Fe-C distance are
2.050(3) in 3 and 2.033(10) Å in 4, as compared with
the value of 2.04(2) Å found in the Cambridge Crystal-
lographic Database;15 mean values of the C-C bond
lengths in cyclopentadienyl rings are 1.424(13) Å in 3
and 1.416(15) Å in 4 (CSD value is 1.42(2) Å). The Cp
rings are planar (largest deviation from the least-
squares plane is 0.011(2) Å and almost parallel; the
dihedral angles between the least-squares planes are
2.75(15)° in 7 and 2.91(14)° in 4. The crystallographic
data of 3 and 4 are presented in Table 2.
Experimental Section
Conclusions
General Procedure: Monomer and Cyclic Product
Characterization. 1H NMR (300 MHz), 13C NMR (75 MHz),
and 29Si NMR (60 MHz) and DEPT spectra were recorded on
a Varian XL 300 MHz spectrometer in CDCl3 solution. Chemi-
cal shifts are reported in δ (ppm) with reference to the residue
portio solvent (CH3Cl) peak for 1H and 13C and to TMS for
29Si. Analytical gas chromatographic (GC) analyses were
Disilacyclic ferrocenophanes containing an exo-meth-
ylene or cis-vinylene fragment between two silicon
(13) Angelakos, C.; Zamble, D. B.; Foucher, D. A.; Lough, A. J.;
Manners, I. Inorg. Chem. 1994, 33, 1709-1718.
(14) Finckh, W.; Tang, B.-Z.; Lough, A.; Manners, I. Organometallics
1992, 11, 2904-2911.
(15) Flack, H. D. Acta Crystallogr. Part A 1983, 39, 876.

Bis(silyl)-[3]-ferrocenophane Derivatives
Organometallics, Vol. 24, No. 15, 2005 3735
Table 2. Crystal Data, Data Collection, and
Structure Refinement
a 250 mL two-necked round-bottomed flask equipped with a
magnetic stirring bar and condenser connected with a bubbler.
After that, the n-butyllithium (25 mL, 40 mmol of 1.6 M
solution in hexane) was added slowly dropwise to a suspension,
the system was stirred for 20 h at room temperature, and a
pale orange dilithium salt [(Fe(η5-C5H4Li)2)‚TMEDA)] was
formed. Then the system was cooled to -78 °C in order to instil
41.77 mmol of chlorodimethylvinylsilane (or chlorodiphenylvi-
nylsilane). After 25 min the mixture was warmed to room
temperature and stirred for additional 8 h. At the subsequent
step, the final mixture was filtered off and excess solvent was
removed under vacuum. The final products were isolated by
the use of column chromatography with silica, using benzene/
hexane as eluent. Each time two components were observed.
The first, light yellow fraction corresponding to a small amount
of ferrocene was discarded. The second fraction was collected
and the solvent removed, obtaining pure compounds: [Fe(η5-
C5H4SiMe2CHdCH2)2] (1), rust-orange liquid, yield 5.29 g
(75%), and [Fe(η5-C5H4SiPh2CHdCH2)2] (2), reddish-yellow
solid, yield 7.19 g (60%).
3
4
formula
fw
cryst syst
space group
a (Å)
b (Å)
c (Å)
C
16H22FeSi2
C
36H30FeSi2
326.37
574.63
monoclinic
P21/n
orthorhombic
P212121
8.9732(9)
14.5210(11)
22.7141(16)
90
9.7611(8)
13.0367(10)
12.7297(10)
100.660(7)
1591.9(2)
4
â (deg)
V (Å3)
Z
2959.6(4)
4
Dx (g cm-3
F(000)
)
1.362
1.2905
688
1200
µ (mm-1
T (K)
)
1.082
0.614
110(1)
295(1)
cryst size (mm)
θ range (deg)
hkl range
0.2 × 0.2 × 0.07
3.26-28.00
-10 e h e 13
-17 e k e 17
-16 e l e 16
0.55 × 0.1 × 0.1
3.03-27.00
-11 e h e 11
-16 e k e 18
-28 e l e 28
1
Analytical Data of [Fe(η5-C5H4SiMe2CHdCH2)2], 1. H
reflections
collected
unique (Rint
NMR (CDCl3; δ (ppm)): 0.27 (s, 12H, -CH3); 4.04 (m, 4H,
C5H4); 4.28 (m, 4H, C5H4); 5.69 (dd, 2H, -CHdCH2); 5.97 (dd,
2H, -CHdCH2); 6.27 (dd, 2H, -CHdCH2). 13C NMR (CDCl3;
δ (ppm)): -2.00 (-CH3); 69.92 (>C-Si in C5H4); 73.11, 71.42
(C5H4); 131.63 (-CHdCH2); 139.05 (-CHdCH2). 29Si NMR
(CDCl3; δ (ppm)): -9.58. MS (FAB, m/z (%)): 354 (M+, 100).
HRMS calcd for C18H26FeSi2: 354.09224. Found: 354.09252.
9932
3821 (0.03)
0.030
0.043
0.92
0.30/-0.31
20 011
6420 (0.048)
0.035
0.047
0.76
0.28/-0.25
)
final R(F) [I > 2σ(I)]
final wR(F2) [all data]
goodness of fit
max./min. ∆F (e Å-3
)
1
Analytical Data of [Fe(η5-C5H4SiPh2CHdCH2)2], 2. H
performed on a Varian Star 3400CX with a DB-5 fused silica
capillary column (30 m × 0.15 mm) and TCD. Mass spectra of
the monomers and products were obtained by GC-MS analysis
(Varian Saturn 2100T, equipped with a BD-5 capillary column
(30 m) and an ion trap detector). High-resolution mass
spectroscopic (HRMS) analyses were made on a AMD-402
mass spectrometer and FAB mass spectra on an AMD-604
instrument (AMD Intectra GmbH). Thin-layer chromatogra-
phy (TLC) was performed on plates coated with 250 µm thick
silica gel (Aldrich), and column chromatography was per-
formed with silica gel 60 (70-230 mesh; Fluka). Benzene and
pentane were dried, having been distilled from sodium hydride;
similarly toluene was from sodium and hexane from calcium
hydride under argon. All liquid substrates were also dried and
degassed by bulb-to-bulb distillation. All the reactions were
carried out under dry argon atmosphere.
Materials. The chemicals were obtained from the following
sources: benzene, toluene, CH2Cl2, pentane, hexane, and
N,N,N′,N′-tetramethylethylenediamine were purchased from
Fluka, CDCl3 from Dr Glaser A.G. Basel, chlorodimethylvi-
nylsilane and chlorodiphenylvinylsilane from Gelest, and
n-buthyllithium and ferrocene from Aldrich. CH2Cl2 was
additionally passed through a column with aluminum oxide.
The ruthenium complexes [RuH(Cl)(CO)(PPh3)3] (I),16a [RuH-
(Cl)(CO)(PCy3)2] (II),16b and [Ru(SiMe3)(Cl)(CO)(PPh3)2] (III)10b
were prepared on the basis of the procedure described in the
above literature.
NMR (CDCl3; δ (ppm)): 4.06 (m, 4H, C5H4); 4.21 (m, 4H, C5H4);
5.78 (dd, 2H, -CHdCH2); 6.29 (dd, 2H, -CHdCH2); 6.62 (dd,
2H, -CHdCH2); 7.37 (m, 16H, m(p)-C6H5); 7.28 (d, 8H,
o-C6H5). 13C NMR (CDCl3; δ (ppm)): 66.28 (>C-Si in C5H4);
72.39, 74.60 (C5H4); 127.57 (m-C6H5); 129.24 (p-C6H5); 134.26
(Si-CHdCH2); 134.63 (Si-C< in C6H5); 135.39 (o-C6H5);
136.15 (Si-CHdCH2). 29Si NMR (CDCl3; δ (ppm)): -16.33. MS
(FAB, m/z (%)): 602 (M+, 100). HRMS calcd for C38H34FeSi2:
602.15484. Found: 602.15523.
General Procedure of Catalytic Examinations. Cata-
lytic tests of cyclization using silylative coupling reactions and
catalytic screenings were essentially performed under argon
using an earlier prepared toluene solution (1 and 0.25 M) with
1,1′-bis(vinylsilyl)ferrocenes derivatives, 1 (and 0.1) mol % of
ruthenium catalysts, and decane as internal standard, at 110
°C for 5 h (and 18 h for 1,1′-bis(vinyldiphenylsilyl)ferrocene)).
The composition of the reaction mixture was analyzed by GC
and GC-MS. The substrate conversion, chemoselectivity of
reaction, and yield were calculated by GC using the internal
standard method.
Synthesis of (Bis(silyl)-[3]-ferrocenophane))ethene De-
rivatives. The syntheses were performed under argon using
[RuH(Cl)(CO)(PCy3)2] (II) as a catalyst. Reagents and solvents
were dried and deoxygenated. The details are presented below.
[(Fe(η5-C5H4SiMe2)2)CdCH2], {(1,1,3,3-Tetramethyl-2-
exo-2-methylene-1,3-disila)-[3]-ferrocenophane}, 3. The
monomer 1 (300 mg, 0.846 mmol), ruthenium complex II (1.2
mg, 1.65 × 10-3 mmol), and toluene (0.85 mL, 1 M) were placed
in a 5 mL minireactor with a magnetic stirring bar and
condenser connected with a bubbler. The reaction mixture was
stirred and heated at 110 °C under an argon flow for 5 h. The
excess solvent was removed under vacuum. The gem-cyclic
product was isolated and purified by repeated reprecipitation
with cold pentane from toluene to afford 254 mg of 3 (0.778
mmol) in 92% as a deep orange crystal.
Representative Procedure for Synthesis of 1,1′-Bis-
(vinylsilyl)ferrocene Derivatives. The title substrates were
synthesized in a manner similar to that reported in ref 17a
with modifications. For the first time, the method of synthesis
of monomer 1 (Scheme 3) was described forty years ago, by
means of hydrosilylation reaction.17b All solvents and chemicals
were dried and distilled under argon prior to use. The main
substratesferrocene was sublimed. The ferrocene (3.70 g,
19.89 mmol), hexane (80 mL), and N,N,N′,N′-tetramethyleth-
ylenediamine (TMEDA; 6.15 mL, 40.77 mmol) were placed into
Analytical Data. 1H NMR (CDCl3; δ (ppm)): 0.31 (s, 12H,
-CH3); 4.12 (m, 4H, C5H4); 4.32 (m, 4H, C5H4); 6.33 (s, 2H,
>CdCH2). 13C NMR (CDCl3; δ (ppm)): -2.09 (-CH3); 68.65
(>C-Si at C5H4); 71.04 (C5H4); 73.34 (C5H4); 138.62 (>CdCH2);
156.29 (>CdCH2, quaternary carbon atom). 29Si NMR (CDCl3;
δ (ppm)): -8.71. MS (FAB, m/z (%)) 326 (M+, 100). HRMS calcd
for C16H23FeSi2: 326.06094. Found: 326.05983. Anal. Calcd
(16) (a) Ahmad, N.; Levison, J. J.; Robinson, S. D.; Uttley, M. F.
Inorg. Synth. 1974, 15, 45. (b) Yi, C. S.; Lee, D. W.; Chen, Y.
Organometallics 1999, 18, 2043.
(17) (a) Garcia, B.; Casado, C. M.; Cuadrado, I.; Alonso, M. M.;
Losada, J. Organometallics 1999, 18, 2349. (b) Greber, V.; Hallensle-
ben, M. L. Makromol. Chem. 1965, 83, 148.

3736 Organometallics, Vol. 24, No. 15, 2005
Majchrzak et al.
for C16H22FeSi2: C, 58.88; H, 6.79, Found: C, 58.82; H, 6.74.
Mp: 58.1-58.3 °C. Single crystals of 3 suitable for X-ray
crystal structure analysis were obtained by recrystallization
from benzene/hexane at room temperature.
eters were determined by a least-squares fit of 3369 (3) and
4103 (4). The structures were solved with SHELXS9721 and
refined with the full-matrix least-squares procedure on F2 by
SHELXL97.22 Scattering factors incorporated in SHELXL93
2
2
were used. The function ∑w(|Fo| - |Fc| )2 was minimized, with
[(Fe(η5-C5H4SiPh2)2)CHdCH], {(Z)-(1,1,4,4-Tetraphenyl-
1,4-disila)-2,3-ethene)-[3]-ferrocenophane}, 4. The mono-
mer 2 (350 mg, 0.581 mmol), ruthenium complex II (4.2 mg,
5.78 × 10-3 mmol), and toluene (2.32 mL, 0.25 M), as a
mixture, was heated in a 5 mL glass minireactor with a
magnetic stirring bar and condenser connected with a bubbler
at 110 °C under an argon flow for 18 h. Then excess solvent
was removed under vacuum. The Z-cyclic product was isolated
and purified by repeated reprecipitation with cold pentane
from toluene to afford 277 mg of 4 (0.482 mmol) in 83% as a
pale reddish powder.
w-1 ) [σ2(Fo)2 + (AP)2], where P ) [Max(Fo , 0) + 2Fc2]/3, A )
2
0.01 for 7 and 0.001 for 4. No empirical extinction corrections
were applied. All non-hydrogen atoms were refined anisotro-
pically. In 3 the positional parameters of hydrogen atoms were
refined; in 4 they were put in idealized positions and refined
as a “riding model”. In both structures Uiso values of hydrogen
atoms were set at 1.2 times Ueq of the appropriate carrier atom.
In the case of 4, which crystallizes in the non-centrosym-
metric space group, the absolute structure was determined on
the basis of the Flack parameter, which converged at 0.003-
(11).15
Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic Data Centre,
Nos. CCDC 250559 (3) and CCDC 250560 (4). Copies of the
data may be obtained free of charge from: The Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, U.K. Fax: +44
(1223) 336-033, e-mail: deposit@ccdc.cam.ac.uk, or www:
http://www.ccdc.cam.ac.uk.
Analytical Data. 1H NMR (CDCl3; δ (ppm)): 4.13 (m, 4H,
C5H4); 4.17 (m, 4H, C5H4); 7.32-7.41 (m, 12H, m(p)-C6H5); 7.51
(s, 2H, Si-CHdCH-Si); 7.59 (d, 8H, o-C6H5). 13C NMR (CDCl3;
δ (ppm)): 72.84 (C5H4); 75.47 (C5H4); 127.80 (o-C6H5); 129.29
(p-C6H5); 135.33 (m-C6H5); 136.78 (>C-Si at C6H5); 149.24
(Si-CHdCH-Si). 29Si NMR (CDCl3; δ (ppm)): -19.31. MS
(FAB, m/z (%)): 574 (M+, 100). HRMS calcd for C36H30FeSi2:
574.12354. Found: 574.12316. Anal. Calcd for C36H30FeSi2: C,
75.24; H, 5.26. Found: C, 75.16; H, 5.21. Mp: 189.8-190.2
°C. Single crystals of 4 suitable for X-ray crystal structure
analysis were obtained by very slow recrystallization from
benzene at room temperature.
Acknowledgment. This work was supported by the
3T09A 145 26.
Supporting Information Available: Tables giving X-ray
crystallographic data for 3 and 4. This material is available
free of charge via the Internet at http://pubs.acs.org.
X-ray Crystal Structure Analysis. For both compounds,
the X-ray diffraction data were measured using graphite-
monochromatized Mo KR radiation (λ ) 0.71073 Å) by
the ω-scan technique on a KUMA-KM4CCD diffractometer
equipped with CCD camera18 with graphite-monochromatized
Mo KR radiation (λ ) 0.71073 Å). The temperature was
controlled by an Oxford Instruments Cryosystem cooling
device. The data were corrected for Lorentz-polarization
effects19 as well as for absorption.20 Accurate unit-cell param-
OM050194X
(19) CrysAlisRed, Program for Reduction of the Data from Kuma
CCD Diffractometer, ver. 171; Oxford Diffraction Poland Sp: Wrocław,
Poland, 2003.
(20) Blessing, R. H. J. Appl. Crystallogr. 1989, 22, 396-397.
(21) Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467-473.
(22) Sheldrick, G. M. SHELXL-97, Program for the Refinement of
Crystal Structures; University of Go¨ttingen: Go¨ttingen, Germany,
1997.
(18) CrysAlisCCD, User Guide ver. 171; Oxford Diffraction Poland
Sp.: Wrocław, Poland, 2003.