Silsesquioxyl rhodium(i) complexes - Synthesis, structure and catalytic activity

Article abstract of DOI:10.1039/c0dt01631d

The first bi- and mononuclear rhodium(i) complexes [{Rh(μ-OSi ₈O₁₂(i-Bu)₇)(cod)}₂] (5), [Rh(cod)(PCy₃)(OSi₈O₁₂(i-Bu)₇)] (6) with a hindered hepta(iso-butyl)silsesquiox

Full text of DOI:10.1039/c0dt01631d

View Article Online / Journal Homepage / Table of Contents for this issue
Dynamic Article Links
Dalton
Transactions
Cite this: Dalton Trans., 2011, 40, 5073
www.rsc.org/dalton
PAPER
Silsesquioxyl rhodium(I) complexes - synthesis, structure and catalytic
activity†
Bogdan Marciniec,* Ireneusz Kownacki, Adrian Franczyk and Maciej Kubicki
Received 24th November 2010, Accepted 2nd March 2011
DOI: 10.1039/c0dt01631d
The first bi- and mononuclear rhodium(I) complexes [{Rh(m-OSi8O12(i-Bu)7)(cod)}2] (5),
[Rh(cod)(PCy3)(OSi8O12(i-Bu)7)] (6) with a hindered hepta(iso-butyl)silsesquioxyl ligand bonded to the
rhodium(I) center through Rh–O–Si bonds have been synthesized and their structures have been solved
by spectroscopic methods and X-ray analysis. Their exemplary catalytic properties in silylative coupling
of vinylsilanes with styrene are also presented.
Introduction
Results and discussion
According to a general idea presented by Wolczanski, TM alkox-
ides and siloxides are alternatives to cyclopentadienyl complexes1
(TM = transition metal). Moreover, siloxy groups with hindered
substituents at silicon, e.g. OSi(O-t-Bu)3, OSi(t-Bu)3 or OSiCy3,
can act as ancillary ligands in formation of low-coordinate reactive
metal centers at a low oxidation state, which particularly applies
to molecular catalysis.1 Since 1982 more than 120 new TM-
siloxide complexes including terminal and/or also bridging siloxy
ligands have been synthesized and characterized by spectroscopic
and X-ray methods to determine their molecular structure2 (for
a review see2a,b and references therein). Molecular compounds
containing a TM–O–Si moiety are also regarded as models for
metal complexes immobilized on silica and silicate surfaces,1–4
particularly in the case of silsesquioxyl5–7 ligands bonded to a metal
centre, which are structurally more relevant to silica than simple
triorganosubstituted siloxyl groups. While complexes of early tran-
sition elements containing siloxyl8 and silsesquioxyl6 ligands are
well-known and characterized, the data on the late TM-complexes
with such ligands in molecular form are scarce. Since 1995 we have
also been involved in TM-siloxide chemistry, particularly of the
late TM-complexes. We had earlier reported synthetic methods
and crystal structures of various binuclear and mononuclear
cobalt(I),9 rhodium(I),10 iridium(I)11 and ruthenium(II)12 siloxide
complexes and applied them in catalytic transformations of
organosilicon compounds, i.e. silylative coupling of olefins with
vinylsilanes,11,13 curing of polysiloxanes via hydrosilylation14 as well
as hydroformylation15 and silylcarbonylation16 of vinylsilanes. In
this communication we present an efficient method for preparation
of bi- and mononuclear silsesquioxyl rhodium(I) complexes as
molecular models of TM-complexes immobilized on silica or
silicate surfaces and discuss their potential application to catalysis.
Starting
organosilicon
materials,
i.e.
chlorohepta(iso-
butyl)silsesquioxane (Si8O12(Cl)(i-Bu)7) (1) as well as the
appropriate hydroxyl derivative (Si8O12(OH)(i-Bu)7) (2) were
synthesized according to modified well-known methods17 (see
Experimental section). Treatment of lithium salt (LiO)Si8O12(i-
Bu)7 (3), obtained after the reaction of HO-silsesquioxane (2)
with n-BuLi (see Experimental section), with binuclear complexes
[{Rh(m-Cl)(cod)}2] (4) in benzene solution gave silsesquioxyl
binuclear rhodium(I) complexes [{Rh(m-OSi8O12(i-Bu)7)(cod)}2]
(5), according to Scheme 1.
Scheme 1 Synthesis of complex 5.
The product was fully characterized by 1H, 13C NMR and 29Si
NMR spectroscopy. The 1H NMR spectrum of [{Rh(m-OSi8O12(i-
Bu)7)(cod)}2] shows two chemically non-equivalent cod-olefinic
resonance lines which appear as broad singlets (presumably owing
to the unresolved coupling and not chemical exchange) at d =
2.57 and 4.52 ppm. The cod-aliphatic signals are hidden between
broad multiples in range 0.84–2.40 ppm assigned to protons of
i-Bu groups bonded to silsesquioxyl core. The 13C NMR spectrum
of 5 is also consistent with a dimeric folded structure and the
cod-olefinic resonance lines are not equivalent and appear at
d = 74.14 ppm (1JRh–C = 12.49 Hz); 78.48 ppm (1JRh–C = 12.24
Hz). Magnetic inequivalence of carbon atoms in the cod ligands
bonded to Rh centres is apparent that the complex has the A-frame
Adam Mickiewicz University, Faculty of Chemistry, ul. Grunwaldzka 6, 60-
780, Poznan´, Poland. E-mail: marcinb@amu.edu.pl; Tel: +48618291366
† CCDC reference numbers 776149 and 776150. For crystallographic data
in CIF or other electronic format see DOI: 10.1039/c0dt01631d
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 5073–5077 | 5073
©

View Article Online
bis-square planar geometry and the two pairs of top olefinic
carbons are close to each other, but the bottom pairs of olefinic
carbons are adjacent to the silsesquioxyl ligands. The cod-aliphatic
signals are located between the lines assigned to i-Bu groups.
The Rh–O–Si(Q4) resonance appears on 29Si NMR spectrum as
a singlet at d = -101.07 ppm. X-Ray analysis of single crystals,
obtained at -30 ◦C by slow evaporation of toluene, confirmed the
binuclear structure of the complex obtained, as shown in Fig. 1.
Scheme 2 Synthesis of complex 6.
cod-aliphatic signals are hidden between broad multiples in the
range 0.83–2.39 ppm assigned to protons of i-Bu and -Cy groups
bonded to silsesquioxyl core and phosphorus atom respectively.
The 13C NMR spectrum of 6 shows non-equivalent cod-olefinic
resonance lines at d = 63.35 (1JRh–C = 15.09 Hz), 100.76 (1JRh–C
=
Fig. 1 The perspective view of complex 5, with hydrogen atoms
omitted for clarity. For disordered fragments only those of larger
occupancy are shown. Selected distances (X1A, X1B are the midpoints
16.09 Hz). The cod-aliphatic signals are located between the lines
assigned to i-Bu and -Cy groups.
i
˚
of double bonds in cod fragment): Rh1–O1 2.091(4) A, Rh1–O1 (i:
To the best of our knowledge, 5 and 6 are the first rhodium-
silsesquioxyl complexes synthesized, whose structures have been
determined by the X-ray method.
The geometry of complex 5, is generally similar to that of
rhodium(I) and iridium(I) trimethylsiloxy analogues, i.e. [{M(m-
OSiMe3)(cod)}2] (M = Rh,10b Ir,11a whose structures were reported
previously. Complex 5 has the exact crystallographic C2 symmetry
(the twofold axis runs between the Rh atoms).
The coordination of Rh ions is square-planar, if the midpoints of
double bonds from cyclooctadiene fragments are regarded as the
coordination sites. Overall the complex has an A-frame bis-square
planar geometry; the roof angle is 125.9◦ and it is larger than in
simpler analogues (120.4◦ in OSiMe3,10b 109.6◦ in OSiPh310e). This
˚
˚
˚
2-x, y, 1/2-z) 2.111(4) A, Rh1–X1A 1.962(5) A, Rh1–X1B 1.973(5) A,
◦
◦
˚
<Si–O> 1.615(9) A, X1A–Rh1–X1B 88.5(3) , X1A–Rh1–O1–173.9(2)◦,
X1A–Rh1–O1i 95.4(2)◦, X1B–Rh1–O1 96.8(2)◦, X1B–Rh1–O1i 173.9(2) ,
O1–Rh1–O1i 79.14(15)◦, Rh1–O1–Rh1i 88.69(13)◦, Si1–O1–Rh1
127.5(2)◦, Si1–Rh1–O1i 143.8(2), <Si–O–Si> 150(5)◦.
Formation of [Rh(cod)(PCy3)(OSi8O12(i-Bu)7)] (6) complex (see
Fig. 2) occurs via a cleavage of two Rh–O–Rh bridging bonds in
the binuclear complex 5 in the presence of PCy3,10d,11b according
to Scheme 2 (see Experimental section).
˚
larger angle results also in longer Rh ◊ ◊ ◊ Rh contact, of 2.937(1) A
˚
˚
(2.812 A in OSiMe3, 2.785 A in OSiPh3), and might be connected
with the larger substituent at the bridging oxygen atom. Similar
geometry to that observed in 5 (roof angle of 129.8◦, Rh ◊ ◊ ◊ Rh
˚
distance 2.983 A) was described for the m-OSiMe3 complex when
cod ligand was exchanged by the norborna-2,5-diene one,10c which
led to the different disposition of the coordination centres at the
double bonds.
In the mononuclear complex 6 the Rh ion is again coordinated
in a square-planar fashion, with the midpoints of double bonds
as coordination centres. Interestingly, the position, with respect to
the O–Si bond, of the substituents at the Si atom closest to the Rh
atom can be described as +sc,-sc, ap (Rh–O–Si–C torsion angles
approximately +60◦, -60◦, 180◦) similarly to previously described
alkyl-substituted siloxyle Rh complexes;10d while this position was
different in the alkoxy-substituted siloxide,10d where it is +ac,-ac,
sp (Rh–O–Si–O values are close to +120◦,-120◦, 0◦).
In both structures the cyclooctadiene ligands are very close
to the lowest-energy C2 boat conformation; the deviations from
this ideal symmetry, measured by the combination of the dihedral
angles called asymmetry parameters,18 are as small as 2.8◦ in 5 and
3.8◦ in 6.
Fig. 2 The perspective view of complex 6, with hydrogen atoms
omitted for clarity. Selected geometrical parameters: (X1A, X1B are
˚
the midpoints of double bonds in cod fragment): Rh1–O1 2.041(3) A,
˚
˚
˚
Rh1–P1 2.3251(14) A, Rh1–X1A 2.090(5) A, Rh1–X1B 1.990(5) A;
◦
◦
˚
<Si–O> 1.623(8) A; X1A–Rh1–X1B 86.7(2) , X1A–Rh1–O1 91.1(2) ,
X1A–Rh1–P1 174.11(14)◦, X1B–Rh1–O1 172.6(2)◦, X1B–Rh1–P1
96.67(15)◦, O1–Rh1–P1 86.16(10)◦, Si1–O1–Rh1 143.1(2)◦, <Si–O–Si>
149(8)◦.
The 1H NMR spectrum of 6 shows two cod-olefinic resonance
lines which appear as broad singlets at d = 3.30 and 5.59 ppm. The
5074 | Dalton Trans., 2011, 40, 5073–5077
This journal is
The Royal Society of Chemistry 2011
©

View Article Online
Table 1 Silylative coupling of vinylsilanes with styrene
and impossible to isolate, formally 16e species (a) with olefin
molecule bonded to the rhodium centre. The formation of a
similar four-coordinated complex of type (a) has been confirmed
spectroscopically for the reaction of [{Ir(m-OSiMe3)(cod)}2] with
H2C CHSi(OSiMe3)3 and H2C CHSi(OEt)3. Further trans-
formation involving Rh 16e intermediate which is generated
in situ, via oxidative addition of = C–H bond of styrene as
a coordinated molecule to the rhodium atom (see Scheme 3,
(a)→(b)), was confirmed for -OSiMe3 analogue by catalytic
vinylic H/D exchange13b between styrene and styrene-d8. The
insertion of vinylsilane into M–H bond (b)→(c)→(d) is followed
by evolution of ethylene (b-Si-transfer) to get five coordinated
Rh–Si intermediate (e). Our previous13b study revealed no traces
of siloxane, PhMe2SiOSiMe3, which would have been the evidence
for replacement of the siloxy ligand by reductive elimination from
the [Rh](SiMe2Ph)(OSiMe3) intermediate. The latter process is
observed in the hydrosilylation of alkene catalyzed by I, i.e., when
[Rh]–H is formed directly by oxidative addition of trisubstituted
silanes, Et3SiH21 and (EtO)3SiH.22
Conversion of
[Rh] mol%) CH2 CHSiR3 (%) product (%)
Yield of
Catalyst
R3= Me2Ph
[{Rh(m-OSiMe3)(cod)}2] 0,1
100
60
92
51
100
87
98
54
84
45
96
79
95
57
0,01
[Rh(cod)(PCy3)(OSiMe3)] 0,1
0,01
0,1
5
0,01
0,1
0,01
6
100
61
R3= (OC2H5)3
[{Rh(m-OSiMe3)(cod)}2]a 1a
100a
100
97
100a
95
95
5
6
0,1
Reaction conditions: [CH2 CHSiR3] : [styrene] = 1 : 3, T = 100 ◦C, t =
1 h, under argon;a [CH2 CHSiR3] : [styrene] = 1 : 10, 90 ◦C, 24 h, under
argon.13a
The rhodium(I) siloxide complexes 5 and 6 were examined in
the silylative coupling of styrene with PhMe2SiCH CH2 and
(EtO)3SiCH CH2, as the testing reactions, and their catalytic ac-
tivities were compared with those of siloxide rhodium(I) precursors
containing –OSiMe3 ligand. The data compiled in Table 1 show
that the new complexes (5 and 6) efficiently catalyze formation
of trans-b-silylstyrene in the presence of 0.01 mol% of rhodium,
particularly in the system consisting H2C CHSiMe2Ph, contrary
to isostructural trimethylsiloxyl analogues, which catalyzed the
silylative coupling of the substrates mentioned when 1 mol%
of rhodium and tenfold excess of styrene were used in the
reaction system. Slight differences in efficiency of new rhodium
silsesquioxyl complexes were observed when H2C CHSi(OEt)3
was used instead of H2C CHSiMe2Ph. We suppose that it is an
effect of three ethoxy groups bonded to the silicone atom in the
initial vinylsilane.
Generally, the complex 5 seems to be more efficient than pre-
catalyst 6 because the cleavage of the binuclear complex via
coordination of styrene is easier than the substitution of PCy3
ligand by styrene in complex 6.
We suppose that better efficiency of the complexes studied is
a result of the steric hindrance and strong electron-withdrawing
effect of silsesquioxyl ligand bonded to the rhodium centre, which
electronic properties are similar to -CF3 group.19 These two effects
make the rhodium centre more reactive in activation of the vinylic
C–H bond in styrene.
As we have reported earlier, rhodium binuclear siloxyl complex
as well as mononuclear siloxide, phosphine complex catalyze
efficiently silylative coupling under milder conditions, than those
reported with well-defined Ru, Rh and Co complexes containing
initially M–H and M–Si bonds (for review see Ref. 20).
The reaction mechanism is proposed on the basis of our previ-
ous mechanistic studies preformed for [{Rh(m-OSiMe3)(cod)}2]13b
complex as well as for iridium(I)11a structural analogue. These
studies have shown that the coupling reaction proceeds according
to the non-metalacarbene mechanism in which, in the first step
olefin (styrene) reacts with binuclear complex 5, giving very labile
Scheme 3 Mechanism of the silylative coupling catalyzed by 5 and 6.
In view of the foregoing, it can be assumed that the complex
5-catalyzed silylative coupling occurs along the same rules as
those catalysed by complex [{Rh(m-OSiMe3)(cod)}2] or [{Ir(m-
OSiMe3)(cod)}2]. When complex 6 is used instead of 5 the
substitution of phosphine ligand by styrene substrate leads to the
formation of complex (a). Further steps of the mechanism proceed
similarly as for complex 5.
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 5073–5077 | 5075
©

View Article Online
Table 2 Crystal data, data collection and structure refinement
In contrast to the previously reported silylative coupling of
olefins with M–H and M–Si complexes (when M = Ru, Rh,
Co, Ir),20 the proposed catalytic cycle does not involve migratory
insertion of olefin into the Rh–Si bond since the final step of
the product formation occurs via reductive elimination of the
product (the dissociative mechanism) regenerating in excess of
styrene complex (a).
Complex
5
6
Formula
C72H150O26Rh2Si16
2087.18
Monoclinic
C2/c
20.084(2)
19.082(2)
28.570(3)
90
98.940(10)
90
10816.2(19)
4
1.28
4416
0.54
2.49 – 27.96
-26 £ h £ 25
-24 £ k £ 24
-37 £ l £ 36
C54H108O13PRhSi8
1324.00
Formula weight
Crystal system
Space group
Triclinic
¯
P1
˚
a/A
10.9023(12)
14.8954(18)
21.769(3)
99.731(12)
98.469(9)
104.467(10)
3306.6(7)
2
˚
b/A
˚
c/A
Conclusions
a (◦)
b (◦)
g (◦)
Two silsesquioxyl bi- (5) and mononuclear (6) rhodium(I) com-
plexes have been synthesized and their structure were solved by
spectroscopic and X-ray methods. Those complexes appeared to
be efficient homogeneous catalysts in the silylative coupling of
vinylsilane with styrene. It is necessary to emphasise, that the
mechanism of catalysis illustrated in Scheme 3 indicates that 5
and 6 are excellent molecular models for transition metal complex
immobilized on silica as a heterogeneous catalyst since TM–O–Si
bond is not cleaved in the catalytic cycle.
3
˚
V/A
Z
dx/g cm-3
F(000)
1.33
1416
0.48
2.85 – 26.00
-13 £ h £ 13
-17 £ k £ 18
-26 £ l £ 26
m/mm-1
H range (0)
hkl range
Reflections:
collected
50571
24946
unique (Rint
)
12106 (0.051)
7342
501
0.068
0.195
0.110
0.204
1.181
0.86/-1.08
12709 (0.049)
7712
719
0.056
0.131
0.096
0.137
0.960
2.31/-0.80
Experimental Section
with I > 2s(I)
Number of parameters
R(F) [I > 2s(I)]
wR(F2) [I > 2s(I)]
R(F) [all data]
Materials and Methods
All synthesis and manipulations were carried out under ar-
gon using standard Schlenk-line and vacuum techniques. The
(Si8O12(Cl)(i-Bu)7) (1), (Si8O12(OH)(i-Bu)7) (2), and (LiO)Si8O12(i-
Bu)7 (3) ligands were synthesized according to a published
method.17 The binuclear complex [{Rh(m-Cl)(cod)}2]23 was syn-
thesized according to the literature. 1H, 13C and 29Si NMR spectra
were recorded on a Varian Gemini 300 VT spectrometer and
Varian Mercury 300 VT in C6D6.
wR(F2) [all data]
Goodness of fit
-3
˚
max/min Dr/e A
as disordered, and weak constraints were applied to the geometry
of the disordered fragments. Relevant crystal data are listed in
Table 2, together with refinement details.
Crystallographic data (excluding structure factors) for the struc-
tural analysis has been deposited with the Cambridge Crystallo-
graphic Data Centre, No. CCDC 776149 (5) and CCDC 776150
(6). Copies of this information may be obtained free of charge
from: The Director, CCDC, 12 Union Road, Cambridge, CB2
1EZ, UK. Fax: +44(1223)336-033, e-mail:deposit@ccdc.cam.
ac.uk, or www.ccdc.cam.ac.uk.
The chemicals were obtained from the following sources:
dimethylphenylvinylsilane, tri(ethoxy)vinylsilane, styrene, n-
butyllithium, cyclooctadiene and C6D6 from Aldrich Chemical
Co.; benzene, pentane from POCH Gliwice (Poland); tricyclo-
hexylphosphine from ABCR; RhCl3·3H2O from Pressure Chem-
R
icals Company; and TriSilanolIsobutyl POSSꢀ from Hybrid
Plastics. All solvents were dried and distilled under argon prior
to use.
Synthetic procedure
Crystallography
Synthesis of [{Rh(cod)(l-OSi8O12)(i-Bu)7)}2] (5). To a portion
of [{Rh(cod)(m-Cl)}2] (4) (0.5g; 1 mmol) placed in a Schlenk flask
under argon, a solution of (LiO)Si8O12(i-Bu)7 (3) (1.76 g; 2.1 mmol)
in 25 mL of benzene was added. The reaction mixture was stirred
for 24 h at room temperature. After this time it was heated to
50 ◦C for 1 h. Subsequently the benzene was evaporated and 2 ¥
20 mL of dried and deoxygenated pentane was added. The entire
mixture was filtered off by a cannula system. Thorough drying and
recrystallization from toluene gave (5) as a yellow microcrystalline
Diffraction data were collected at room temperature for 5 and
at 100(1) K for 6 by the w-scan technique, on an Xcalibur
Eos diffractometer24 with graphite-monochromatized Mo-Ka
˚
radiation (l = 0.71073 A). The temperature was controlled by
an Oxford Instruments Cryosystems cooling device. The data
were corrected for Lorentz polarization and absorption effects.25
Accurate unit-cell parameters were determined by a least-squares
fit of 13335 (5) and 9078 (6) reflections of highest intensity, chosen
from the whole experiment. The structure was solved with SIR9225
and refined with the full-matrix least-squares procedure on F2 by
SHELXL97.26
Scattering factors incorporated in SHELXL97 were used. All
non-hydrogen atoms were refined anisotropically; hydrogen atoms
were placed in calculated positions, and refined using a ‘riding
model’ with the isotropic displacement parameters set at 1.2 (1.5
for methyl groups) times the Ueq value for the appropriate non-
hydrogen atom. In both cases some of the i-Bu groups were refined
1
material (3.13 g, 1.50 mmol, 75%). H NMR (C6D6, d, ppm):
0.84–2.40 (d, 84H, -CH3, i-Bu; t, 28H, -CH2-Si, i-Bu; m, 14H,
-CH-, i-Bu; bs, 8H, -CH2-, cod); 4.52, 2.57 (bs, 8H, = CH, cod).
13C NMR (C6D6, d, ppm): 22.78, 23.01, 24.38, 24.42, 25.92, 26.41,
31.29 (28C, -CH3; 14C, -CH2–Si; 14C, -CH-; 8C, -CH2-); 74.14
(1JC–Rh = 12.49 Hz); 78.48 (1JC–Rh = 12.24 Hz) (8C, = CH-) 29Si NMR
(INEPT) (C6D6, d, ppm): -67.42(Q3); -67.52(Q3); -101.07(Q4).
Elemental Anal. Calcul. for C72H150O26Rh2Si16 C, 41.44; H, 7.58
Found: C 42.05; H 7.69.
5076 | Dalton Trans., 2011, 40, 5073–5077
This journal is
The Royal Society of Chemistry 2011
©

View Article Online
Synthesis of [Rh(cod)(PCy3)(l-OSi8O12)(i-Bu)7)] (6). Portions
of [{Rh(cod)(m-OSi8O12)(i-Bu)7)}2] (5) (0.5g; 0.24 mmol) and PCy3
(0.134 g, 0.48 mmol) were placed in a Schlenk flask in an argon
atmosphere. Then 10 ml of dried and deoxygenated benzene were
added. The reaction was carried out for 12 h at room temperature.
After this time the benzene was removed yielding a yellow solid
of (6) (0.616 g, 0.475 mmol, 98%).1H NMR (C6D6, d, ppm): 0.83–
2.39 (d, 42H, -CH3, i-Bu; t, 14H, -CH2-Si, i-Bu; m, 7H, -CH-, i-Bu;
bs, 4H, -CH2-, cod); 3.30 (bs, 2H, = CH, cod), 5.59 (bs, 2H, = CH,
cod).13C NMR (C6D6, d, ppm): 23.27, 23.83, 24.49, 24.57, 26.01,
26.29, 26.93, 28.10, 28.20, 28.75, 30.53, 31.41, 32.58, 33.85 (14C,
-CH3; 7C, -CH2–Si; 7C, -CH-; 8C, -CH2-); 63.35 (1JC–Rh = 15.09
Hz), 100.76 (1JC–Rh = 16.09 Hz) (4C, = CH-). 31P NMR (C6D6,
d, ppm): 26.27 (d, JRh–P = 149.15 Hz) 29Si NMR (INEPT) (C6D6,
d, ppm): -67.53(Q3); -68.20(Q3); -102.21(Q4). Elemental Anal.
Calcul. for C54H108O13PRhSi8 C, 48.98; H, 7.86 Found: C 49.05; H
7.95.
5 R. Duchateau, Chem. Rev., 2002, 102, 3525–3542.
6 (a) E. A. Quadrelli and J.-M. Basset, Coord. Chem. Rev., 2010, 254,
707–728; (b) D. B. Cordes, P. D. Lickiss and F. Rataboul, Chem. Rev.,
2010, 110, 2081–2173.
7 H. C. L. Abbenhuis, Chem.–Eur. J., 2000, 6, 25–32.
8 (a) G. C. Bruce and S. R. Stobart, Inorg. Chem., 1988, 27, 3879–3880;
(b) K. J. Covert, P. T. Wolczanski, S. A. Hill and P. J. Krusic, Inorg.
Chem., 1992, 31, 66–78; (c) L. J. C. Chamberlain, J. Huffman, I. P.
Keddington and P. Rothwell, J. Chem. Soc., Chem. Commun., 1982,
805–806; (d) B. D. Steffey, P. E. Fanwick and P. Rothwell, Polyhedron,
1990, 9, 963–968; (e) O. W. Steward and D. R. Fussaro, J. Organomet.
Chem., 1977, 129, C28–C32; (f) S. Shambayatei, J. F. Blake, S. G.
Wierschke, W. L. Jorgensen and S. L. Schreiber, J. Am. Chem. Soc.,
1990, 112, 6155–6156; (g) T. V. Lubben, P. T. Wolczanski and G. D. Van
Duyne, Organometallics, 1984, 3, 977–983; (h) M. Nandi, D. Rhubright
and A. Sen, Inorg. Chem., 1990, 29, 3066–3068.
9 I. Kownacki, M. Kubicki and B. Marciniec, Polyhedron, 2001, 20, 3015–
3018.
10 (a) B. Marciniec and P. Krzyz˙anowski, J. Organomet. Chem., 1995,
493, 261–266; (b) P. Krzyz˙anowski, M. Kubicki and B. Marciniec,
Polyhedron, 1996, 15, 1–4; (c) B. Marciniec, P. Krzyz˙anowski and
M. Kubicki, Polyhedron, 1996, 15, 4233–4239; (d) B. Marciniec, P.
Błazejewska-Chadyniak and M. Kubicki, Can. J. Chem., 2003, 81,
1292–1298; (e) A. J. Vizi-Orosz, R. Ugo, R. Psaro, A. Sironi, M. Moret,
C. Zucchi, F. Ghelfi and G. Palyi, Inorg. Chem., 1994, 33, 4600–4603.
11 (a) B. Marciniec, I. Kownacki and M. Kubicki, Organometallics, 2002,
21, 3263–3270; (b) I. Kownacki, M. Kubicki and B. Marciniec, Inorg.
Chim. Acta, 2002, 334, 301–307; (c) I. Kownacki, M. Kubicki, K.
Szubert and B. Marciniec, J. Organomet. Chem., 2008, 693, 321–328.
12 S. Rogalski, C. Pietraszuk and B. Marciniec, J. Organomet. Chem.,
2009, 694, 3918–3922.
13 (a) B. Marciniec, E. Walczuk-Gusciora and P. Blazejewska-Chadyniak,
J. Mol. Catal. A: Chem., 2000, 160, 165–171; (b) B. Marciniec, E.
Walczuk-Gusciora and C. Pietraszuk, Organometallics, 2001, 20, 3423–
3428.
14 (a) I. Kownacki, B. Marciniec, A. Macina, S. Rubinsztajn and D. Lamb,
Appl. Catal., A, 2007, 317, 53–57; (b) B. Marciniec, I. Kownacki,
M. Kubicki, P. Krzyz˙anowski, E. Walczuk and P. Błaz˙ejewska-
Chadyniak, in Perspectives in Organometallic Chemistry, Royal Society
of Chemistry, (Eds, C. G. Screttas and B. R. Steele), Cambridge, UK,
2003, 253-265.
Catalytic examinations in silylative coupling of styrene with
trisubstituted vinylsilane
The catalytic tests of the rhodium(I) silsesquioxide complexes
in silylative coupling reactions were performed in glass am-
poules or Schlenk tubes filled with a mixture of reagents:
(1.8 mmol) styrene and (0.6 mmol) dimethylphenylvinylsilane
or tri(ethoxy)vinylsilane, appropriate amounts of catalyst (3 ¥
10-4 mmol (3 ¥ 10-5 mmol) of (5) or 6 ¥ 10-4 mmol (6 ¥ 10-5
mmol) of (6)) and decane as an internal standard. The ampoules
◦
(or Schlenk tubes) were heated at 100 C for one hour under an
argon atmosphere. The distribution of substrates and products,
conversion of substrates and the yield of products were determined
by GC and GC-MS analyses.
15 E. Mieczyn´ska, A. M. Trzeciak, J. J. Zio´łkowski, I. Kownacki and B.
Marciniec, J. Mol. Catal. A: Chem., 2005, 237, 246–253.
16 I. Kownacki, B. Marciniec, K. Szubert and M. Kubicki,
Organometallics, 2005, 24, 6179–6183.
17 R. Duchateau, U. Cremer, R. J. Harmsen, S. I. Mohamud, H. C. L.
Abbenhuis, R. A. van Santen, A. Meetsma, S. K.-H. Thiele, M. F. H.
van Tol and M. Kranenburg, Organometallics, 1999, 18, 5447–5459.
18 W. L. Duax and D. A. Norton, Atlas of Steroid Structures, New York,
Plenum, 1975.
Acknowledgements
This work was made possible by a grant (NR 05 0005 04/2008)
from the Ministry of Science and Higher Education and
Ventures/2010-6/3, project operated within the Foundation for
Polish Science, co-financed by the European Regional Develop-
ment Fund, Operational Program Innovative Economy 2007–
2013.
19 F. J. Feher and T. A. Budzichowski, J. Organomet. Chem., 1989, 379,
33–40.
20 B. Marciniec, Coord. Chem. Rev., 2005, 249, 2374–2390.
21 B. Marciniec, P. Krzyzanowski, E. Walczuk-Gusciora and W. Duczmal,
J. Mol. Catal. A: Chem., 1999, 144, 263–271.
22 S. B. Duckett and R. N. Perutz, Organometallics, 1992, 11, 90–98.
23 (a) I. Matsuda, A. Ogisto and S. Sato, J. Am. Chem. Soc., 1990,
112, 6120–6121; (b) I. Matsuda, J. Skakibara and H. Nagashima,
Tetrahedron Lett., 1991, 32, 7431–7434.
Notes and references
1 T. Wolczanski, Polyhedron, 1995, 14, 3335–3362.
2 (a) B. Marciniec and H. Maciejewski, Coord. Chem. Rev., 2001, 223,
301–335, and references therein; (b) B. Marciniec, in Education in
Advanced Chemistry, (Eds, A. Trzeciak and P. Sobota), 2005, vol. 9,
195-214.
24 Oxford Diffraction 2009 CrysAlis PRO (Version 1.171.33.36d). Oxford
Diffraction Ltd.
3 (a) F. R. Hartley, Supported Metal Complexes (Ed. Reidel), Boston,
1985; (b) Y. Iwasawa, (Ed. Tailoral) Metal Catalysts (Ed. Reidel),
Boston, 1986.
25 A. Altomare, G. Cascarano, C. Giacovazzo and A. Gualardi, J. Appl.
Crystallogr., 1993, 26, 343–350.
26 G. M. Sheldrick, Acta Crystallogr., Sect. A: Found. Crystallogr., 2008,
A64, 112–122.
4 F. J. Feher, J. Am. Chem. Soc., 1986, 108, 3850–3852.
This journal is
The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 5073–5077 | 5077
©