A posteriori modification of carbosilane dendrimers and dendrons: Their activation in core and branch positions

Article abstract of DOI:10.1039/b501069a

The introduction of phenyl groups at different points on carbosilane dendrimers allows their acidolytic conversion to highly reactive triflato groups which in turn are readily substituted by anionic nucleophiles. Core phenylated first-fourth generation dendrimers were synthesized from tri(allyl)phenylsilane by an alternating sequence of hydrosilylation and allylation steps. Similarly, carbosilane dendrimers containing phenyl-Si groups at the branching points and in the periphery were prepared from tetraallylsilane which was hydrosilylated with PhHSiCl₂. Reaction of the phenylated dendrimers with triflic acid in toluene cleanly gave the silyl Inflate derivatives, provided that the correct stoichiometry of the reagents was used. In the presence of a large excess of triflic acid the SiMe₃-end groups are slowly converted to SiMe₂(OTf)-units. The proof of concept was provided by the fixation of a {Ph₂PCH₂} group using the lithiated diphenylphosphinomethanide Ph₂PCH₂Li, obtained by cleavage of Ph₃SnCH₂PPh₂ with PhLi, as well as a lithiated ether-alcohol functionalized triphos derivative to the core of a third generation carbosilane dendrimer. The Royal Society of Chemistry 2005.

Full text of DOI:10.1039/b501069a

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F U L L P A P E R
“A posteriori” modification of carbosilane dendrimers and dendrons:
their activation in core and branch positions
Arno Tuchbreiter,a,b Helmut Wernerb and Lutz H. Gade*a
a Anorganisch-Chemisches Institut, Universita¨t Heidelberg, Im Neuenheimer Feld 270, 69120,
Heidelberg, Germany. E-mail: lutz.gade@uni-hd.de
b Institut fu¨r Anorganische Chemie, Universita¨t Wu¨rzburg, Am Hubland, 97074, Wu¨rzburg,
Germany
Received 21st January 2005, Accepted 3rd March 2005
First published as an Advance Article on the web 15th March 2005
The introduction of phenyl groups at different points on carbosilane dendrimers allows their acidolytic conversion to
highly reactive triflato groups which in turn are readily substituted by anionic nucleophiles. Core phenylated
first–fourth generation dendrimers were synthesized from tri(allyl)phenylsilane by an alternating sequence of
hydrosilylation and allylation steps. Similarly, carbosilane dendrimers containing phenyl-Si groups at the branching
points and in the periphery were prepared from tetraallylsilane which was hydrosilylated with PhHSiCl2. Reaction of
the phenylated dendrimers with triflic acid in toluene cleanly gave the silyl triflate derivatives, provided that the correct
stoichiometry of the reagents was used. In the presence of a large excess of triflic acid the SiMe3-end groups are slowly
converted to SiMe2(OTf)-units. The proof of concept was provided by the fixation of a {Ph2PCH2} group using the
lithiated diphenylphosphinomethanide Ph2PCH2Li, obtained by cleavage of Ph3SnCH2PPh2 with PhLi, as well as a
lithiated ether-alcohol functionalized triphos derivative to the core of a third generation carbosilane dendrimer.
topologically different environments are completely convertible
Introduction
to triflates was a practical question to be resolved in this study.
Among the many known classes of dendrimers which have been
Finally, we were interested in establishing the possibility of using
developed during the past 2.5 decades,1 dendritic carbosilanes
these activated dendrimers for the immobilization of phosphine
were found to be particularly suited as platforms for further
ligands, which may be employed in catalytic applications of these
functionalization.2 This is due to their high kinetic and ther-
systems.
modynamic stability and the low polarity of the Si–C bond.
This inertness has even enabled the selective oxygenation of
the end groups in carbosilane dendrimers with H2O2 and wide
diversity of types of functionalization even under harsh reaction
conditions.3
The first carbosilane dendrimer was reported as early as 1978
by Fetters and co-workers,4 however, the field really opened up
in the 1990s after the seminal contributions by van der Made
and van Leeuwen et al.,5 Roovers et al.,6 Muzafarov et al.7 as
well as from Seyferth’s group.8
The aim of this work was the possibility of selectively function-
alizing carbosilane dendrimers in the core, the branching units
and at end groups subsequent to their divergent synthesis.
The key step in the growth sequence is the hydrosilylation
of olefinic end groups, a catalytic reaction which is not very
tolerant towards functional groups. It was thus desirable to
convert relatively inert molecular fragments to highly reactive
functionalities within the dendrimer structure. A well established
method of functionalization in carbosilane chemistry is the
cleavage of Si-phenyl units by strong mineral acids, in particular
trifluoromethansulfonic acid.9 While frequently employed in the
synthesis of “simple” silicon compounds this method has not
been used in dendrimer chemistry.
Results and discussion
Synthesis of G1–G4 carbosilane dendrimers containing a
PhSiR3 core
The syntheses of the core phenylated first–fourth generation
dendrimers 1–10 were carried out according to the method estab-
lished for carbosilane dendrimers by Roovers, van Leeuwen and
Seyferth.5,6,8 As the core molecule we chose tri(allyl)phenylsilane
from which the dendrimer growth was achieved by an alternating
sequence of hydrosilylation and allylation steps (Scheme 1).
The hydrosilylations were carried out in benzene using
Karsted’s catalyst which avoided the formation of possible
regioisomers. The chloroterminated carbosilanes were then
reacted with (allyl)MgBr giving the next-generation dendrimers
containing allyl end groups. While compounds 3–6, which were
employed as branching elements in composite polymers with
polyolefins, have been reported previously,10 they remained
incompletely characterized. The final step in the dendrimer
synthesis was the methylation of the end groups using MeMgCl
(Scheme 2).
The third- and fourth-generation core-phenylated dendritic
carbosilanes 7 and 10 were the objects of study in the subsequent
acidolytic activation and functionalization steps.
Synthesis of carbosilane dendrimers containing phenyl-Si groups
at the branching points and at the periphery
With the aim of synthesizing a carbosilane dendrimer which
is phenylated both at the branching points as well as the
end groups, tetraallylsilane11 was hydrosilylated with PhHSiCl2
The strategy is thus straightforward: introducing phenyl
groups at different points of a carbosilane dendrimer as
“dummy” functions which can be selectively converted to highly
reactive triflato groups which in turn are readily substituted
by anionic nucleophiles. To which degree dummy functions in
1
giving compound 11 (Scheme 3). In the H NMR spectrum of
the compound the outer methylene groups of the propylene units
resonate as triplets at d 0.58 and 1.35 ppm, the latter being
assigned to the protons adjacent to the SiPhCl2 groups, while
1 3 9 4
D a l t o n T r a n s . , 2 0 0 5 , 1 3 9 4 – 1 4 0 2
T h i s j o u r n a l i s
T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 5
©

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Scheme 2 Methylation of the SiMeCl2 end groups of the G2 and G3
carbosilane dendrimers 6 and 9.
cleavage of the Si-phenyl unit could also be achieved with one
molar equivalent of triflic acid albeit at a much slower conversion
rate). The quantitative conversion could be readily followed by
1H NMR spectroscopy which showed the absence of the phenyl
resonances at the end of the reaction. The chemical shift of
the other resonances of the reaction product 15 differed only
1
slightly from those of 2. In the 13C{ H} NMR spectrum a quartet
resonance at d 118.4 ppm is observed which is due to the CF3-
group of the triflate.
As for the first-generation dendrons 2 and 15, the 1H, 13C and
29Si NMR spectra of the third- and fourth-generation products
16 and 17 closely resemble those of the phenylated starting
materials 7 and 10, with only the signals of the phenyl groups
1
being absent. The shift of the resonances in the 29Si{ H} NMR
spectrum of d −3.8 ppm for 7 to d 39.7 ppm for 16 and from d
−3.8 ppm for 10 to d 39.8 ppm for 17 indicates the substitution
of the core phenyl unit by a triflato function.
In order to obtain high selectivities in the acidolytic cleavage
it is important to closely observe the correct stoichiometry of the
reagents. In the presence of an excess of triflic acid the SiMe3-end
groups are slowly converted to SiMe2(OTf)-units. To study this
side reaction we exposed compound 2 to a tenfold excess of the
acid, which not only led to the cleavage of the core-phenyl group
but a complete and clean conversion of all three SiMe3 termini
to dimethylsilyltriflato units giving compound 18 (Scheme 5).
Scheme 1 Synthesis of the G0–G3 carbosilane dendrimers 1–7, 8, 9
containing a PhSiR3 core.
signal of the CH2-group in the middle is observed as a multiplet
at d 1.46–1.77. The 13C NMR signals are observed at d 15.8, 17.3
and 24.9 ppm. The 29Si nucleus at the core position resonates at
d 1.5 ppm whereas the peripheral SiPhCl2 groups give rise to a
29Si NMR signal at d 18.3 ppm.
1
Following the reaction by H NMR spectroscopy showed that
the phenyl group is very rapidly eliminated with a subsequent
slower cleavage of the Si–CH3 bonds.
Reacting 11 with allylmagnesium bromide in thf giving
compound 12 and a subsequent further hydrosilylation step
with PhHSiCl2 yielded the first-generation dendrimer 13
which was subsequently methylated with MeMgCl in THF
to give Si[CH2CH2CH2Si(Ph)[CH2CH2CH2Si(Ph)Me2]2]4 (14)
(Scheme 3) which was characterized, similar to the other
The selectivity of this reaction is remarkable in that only one
methyl group per SiMe3 unit is cleaved in spite of the large excess
of the acid. This is due to a significant decrease of electron
density at the silicon atom upon replacement of a CH3 group
by the triflate thus deactivating this position with respect to
further acidolytic transformations, a behaviour which has been
previously noted in silicon chemistry.9b The subsequent reaction
step therefore occurs at a different SiMe3 unit in the periphery.
A controlled and rapid acidolytic transformation both at the
branching points and the end groups was achieved by reaction of
the phenylated first generation dendrimer 14 with 12 equivalents
of triflic acid, cleanly giving the dodecatriflate 19 (Scheme 6). In
1
compounds, by elemental analysis, H, 13C, 29Si NMR and IR
spectroscopy, as well as FAB mass spectrometry.
Acidolytic cleavage of the phenyl-Si groups in dendrimers with
triflic acid giving triflato-Si core units
The acidolytic cleavage of the core-phenylated carbosilane den-
drimers was carried out using compounds 2, 7 and 10 (Scheme 4).
Reaction of carbosilane 2 with three molar equivalents of triflic
acid in toluene cleanly gave the silyl triflate derivative (a complete
1
the H NMR spectrum of compound 19 all signals are shifted
D a l t o n T r a n s . , 2 0 0 5 , 1 3 9 4 – 1 4 0 2
1 3 9 5

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Scheme 3 Synthesis of the carbosilane dendrimers 11–14 containing phenyl-Si groups at the branching points and in the periphery.
NMR spectrum of the compound. The synthesis of 19 clearly
demonstrates the versatility of the acidolytic modification of
phenylated dendrimers which is feasible in the core, branching
and endgroup positions of a dendritic carbosilane.
Fixation of a monodentate and a tripodal phosphine to the core
of a G3–R3Si(OTf) carbosilane dendrimer
The acidolysis of the phenyl groups provided a means of
activation of a relatively inert carbosilane dendrimer. In order to
demonstrate the possibility of “a posteriori” functionalization
we attached two different ligand systems via different linker
functions to the silyltriflato units of the third generation
dendrimer 16.
The first such modification concerned the introduction
of a {Ph2PCH2} group using the lithiated diphenylphosphi-
nomethanide Ph2PCH2Li. The latter may be synthesized by
direct lithiation of R2PCH3 with lithium alkyls,12 however, this
method generally leads to variable degrees of metallation of
the methyl phosphine and consequently to product mixtures.
In order to avoid this complication we chose a different
synthetic route for Ph2PCH2Li by nucleophilic cleavage of
Ph3SnCH2PPh2 with PhLi. This method is based on previous
work by Kauffmann et al.13 as well as the group of one of
us,14 and produced the desired lithium methanide very cleanly.
Upon addition of a stoichiometric amount of dendrimer 16 and
subsequent work up the target compound 21 was isolated as a
colourless oil in good yield (Scheme 7).
Scheme 4 Acidolytic cleavage of the core phenyl-Si groups in PhSiR3
dendrimers with triflic acid giving triflato-Si core units.
Scheme 5 Acidolytic cleavage of the core phenyl-Si group in 2 and
conversion of the SiMe3 end groups into SiMe2(OTf) groups in the
presence of a large excess of triflic acid.
As a second target for ligand fixation we employed an
ether-alcohol functionalized triphos derivative which we had
previously attached to the periphery of carbosilane dendrimers
employed in hydrogenation catalysis.15 Reaction of 16 with the
in situ lithiated tripodal phosphine readily gave the dendritic
to lower field due to the introduction of twelve electronegative
triflato groups, while there is a complete absence of phenyl
1
resonances. The same general trend is observed in the 13C{ H}
Scheme 6 Acidolytic cleavage of the phenyl-Si groups at the branching points and in the periphery of 14 giving the highly reactive triflato-Si
derivative 19.
1 3 9 6
D a l t o n T r a n s . , 2 0 0 5 , 1 3 9 4 – 1 4 0 2

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1
by centrifugation. The H, 19F and 13C Si NMR spectra were
recorded on Bruker AC 200, Bruker Avance 250 and Bruker
AMX 400 FT NMR spectrometers (reference: tetramethylsi-
lane), using the residual protonated solvent peak (1H) or the
carbon resonance (13C). IR spectra were recorded on a Nico-
let Magna IRTM 750 spectrometer. Elemental analyses were
carried out by the microanalytical service at the chemistry de-
partment at Strasbourg. Triallylphenylsilane,16 tetraallylsilane,11
15
HO(CH2)2OCH2C(CH2PPh2)3 and iodomethyltriphenylstan-
nane17 were prepared according to published procedures. All
other chemicals used as starting materials were obtained com-
mercially and used without further purification.
Preparation of the compounds
PhSi[CH2CH2CH2Si(Me)Cl2]3
(1). Phenyltriallylsilane
(1.84 g, 8.07 mmol), MeHSiCl2 (4.18 g, 36.3 mmol) and 50 ll
of Karstedt’s catalyst were slowly heated in 5 ml of benzene
until a weakly exothermic reaction set in and the colourless
solution turned pale yellow. The reaction mixture was stirred at
55 ◦C for 16 h. After cooling to room temperature, the volatiles
were removed in vacuo and compound 1 was obtained as an
analytically pure, pale yellow oil. Yield: 4.63 g (8.07 mmol,
100%). 1H NMR (400.14 MHz, CDCl3, 295 K): d 0.76 (s, 9 H,
3
3
H-10), 0.98 (t, 6 H, JHH = 8.5 Hz, H-6), 1.22 (t, 6 H, JHH
=
7.9 Hz, H-8), 1.56–1.63 (m, 6 H, H-7), 7.38–7.50 (m, 5 H,
1
H-2,H-3, H-4). 13C{ H} NMR (100.6 MHz, CDCl3, 295 K):
d 5.4 (C-10), 15.8 (C-6/7/8), 17.2 (C-6/7/8), 25.7 (C-6/7/8),
128.0 (C-3), 129.2 (C-4), 133.9 (C-2), 136.0 (C-1). 29Si{ H}
1
NMR (59.6 MHz, CDCl3, 295 K): d −3.4 (Si-5), 32.3 (Si-9). IR
(neat): m 3069vw, 2925m, 1451vw, 1427w, 1403w, 1339w, 1261s,
1148m, 1109m, 1021w, 943w, 906m, 815s, 787s, 738m, 700m,
536s cm−1. C18H32Si4Cl6 (573.51 g mol−1): calc.: C 37.70, H 5.63;
found: C 37.76, H 5.68%.
PhSi[CH2CH2CH2SiMe3]3 (2). To a solution of compound
1 (2.29 g, 4.00 mmol) in 40 ml of thf, which was cooled to
−5 ◦C, were added 11.2 ml (33.6 mmol) of a 3.00 molar solution
of methylmagnesium chloride in thf over a period of 1.5 h.
The reaction mixture was refluxed for 23 h, cooled to room
temperature and then added slowly to 50 ml of a cooled aqueous
solution of NH4Cl. After separation of the organic layer, the
aqueous phase was twice extracted with 30 ml of hexane, the
combined organic phases were washed with 30 ml of brine
and then dried over Na2SO4. After removal of the solvent and
volatiles in vacuo, the residual viscous yellow oil was purified
by column chromatography (SiO2, 15 cm, hexane–ethyl acetate
6 : 1). Compound 2 was obtained as a colourless viscous oil.
Yield: 1.25 g (2.77 mmol, 69%). 1H NMR (400.14 MHz, CDCl3,
Scheme 7 Fixation of a monodentate and a tripodal phosphine to the
core of the G3–R3Si(OTf) carbosilane dendrimer 16.
derivative 22. As for compound 21 the main difference in the
NMR spectra of this functionalized system with respect to those
of 16 concerns the methylene protons adjacent to the Si-core
(d 0.86 ppm) as well as the protons in the ethylene bridge of the
linker at the triphos ligand.
Conclusion
In this work we have presented a convenient strategy to intro-
duce “masked” functionality into carbosilane dendrimers. The
dendrimer synthesis is performed with the chemically relatively
inert phenylsilane derivatives which do not interfere negatively
with hydrosilylation catalysis. Acidolytic cleavage of the phenyl-
Si units using stoichiometric amounts of triflic acid then
generates highly reactive triflatosilyl units at the core, branching
points or the periphery of carbosilane dendrimers which allow a
facile subsequent nucleophilic substitution at these points. This
method allows the introduction of functional groups, catalytic
sites etc. into carbosilane dendrimers “a posteriori” to their
synthesis.
3
295 K): d −0.05 (s, 27 H, H-10), 0.57 (t, 6 H, JHH = 8.2 Hz,
H-8), 0.83 (t, 6 H, 3JHH = 8.2 Hz, H-6), 1.33–1.41 (m, 6 H, H-7),
1
7.31–7.48 (m, 5 H, H-2, H-3, H-4). 13C{ H} NMR (100.6 MHz,
CDCl3, 295 K): d −1.5 (C-10), 17.3 (C-6/7/8), 18.5 (C-6/7/8),
21.6 (C-6/7/8), 127.6 (C-3), 128.5 (C-4), 134.1 (C-2), 138.3 (C-
1
1). 29Si{ H} NMR (79.5 MHz, CDCl3, 295 K): d −3.9 (Si-5),
0.7 (Si-9). IR (neat): m 3068vw, 3050vw, 2952s, 2913s, 2874m,
1449vw, 1427w, 1412w, 1334w, 1259m, 1247s, 1141m, 1108m,
1022w, 943w, 907m, 862s, 834s, 734m, 698s cm−1. C24H50Si4
(451.00 g mol−1): calc.: C 63.92, H 11.17; found: C 64.03,
H 10.84%.
Experimental
All manipulations were performed under nitrogen. Solvents were
dried according to standard methods and saturated with nitro-
gen. The deuterated solvents used for the NMR spectroscopic
measurements were degassed by three successive “freeze–pump–
˚
thaw” cycles and stored over 4-A molecular sieves. Solids were
PhSi[CH2CH2CH2Si(Me)(allyl)2]3 (3). To a solution of 1
(4.63 g, 8.07 mmol) in 5 ml of thf, which was cooled to −5 ◦C,
separated from suspensions by filtration through dried Celite or
D a l t o n T r a n s . , 2 0 0 5 , 1 3 9 4 – 1 4 0 2
1 3 9 7

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84 ml (67.8 mmol) of a 0.81 molar solution of allylmagnesium
bromide were slowly added over a period of 1.5 h. The reaction
mixture was heated under reflux for 24 h, then cooled to
room temperature and slowly poured into 100 ml of a cooled
aqueous solution of NH4Cl. After separation of the organic
layer, the aqueous phase was twice extracted with 50 ml of
hexane, the combined organic phases washed with 50 ml of
brine and then dried over Na2SO4. After the removal of the
solvent and volatiles in vacuo, the residual viscous yellow
oil was purified by column chromatography (SiO2, 15 cm,
hexane). Compound 3 was obtained as a viscous colourless
127.7 (C-3), 128.6 (C-4), 134.0 (C-2), 135.2 (C-17), 138.0 (C-1).
1
29Si{ H} NMR (79.5 MHz, CDCl3, 295 K): d −4.0 (Si-5), 0.3
(Si-14), 1.1 (Si-9). IR (neat): m 3075w, 2994vw, 2970w, 2954w,
2912m, 2876m, 1629s, 1419m, 1333vw, 1252s, 1192vw, 1153s,
1108vw, 1031m, 990m, 931m, 893s, 814br m, 699m, 591m cm−1.
C78H146Si10 (1364.87 g mol−1): calc.: C 68.64, H 10.77; found: C
68.90, H 10.45%.
liquid. Yield: 3.92 g (6.46 mmol, 80%).1H NMR (400.14 MHz,
3
CDCl3, 295 K): d −0.05 (s, 9 H, H-10), 0.63 (t, 6 H, JHH
=
PhSi[CH2CH2CH2Si(Me)[CH2CH2CH2Si(Me)[CH2CH2CH2-
Si(Me)Cl2]2]2]3 (6). Same general procedure as for compound
4, using 2.52 g (1.85 mmol) of 5 and 4.34 g (37.7 mmol) of
MeHSiCl2. The reaction product, compound 6 was obtained as
a pale yellow liquid. Yield: 5.08 g (1.85 mmol, 100%). 1H NMR
(400.14 MHz, CDCl3, 295 K): d −0.12 (s, 9 H, H-10), −0.05
(s, 18 H, H-15), 0.48–0.63 (m, 54 H, H-8, H-11, H-13, H-16),
0.75 (s, 36 H, H-20), 0.82 (t, 6 H, 3JHH = 8.2 Hz, H-6), 1.16 (t,
3
8.2 Hz, H-8), 0.84 (t, 6 H, JHH = 8.2 Hz, H-6), 1.32–1.40 (m,
6 H, H-7), 1.51 (dt, 12 H,3JHH = 8.2 Hz, JHH = 1.2 Hz, H-
5
11), 4.80 (t, 6 H, 3JHH = 1.2 Hz, H(cis)-13), 4.81–4.83 (m, 6 H,
H(trans)-13), 5.68–5.79 (m, 6 H, H-12), 7.32–7.45 (m, 5 H, H-2,
H-3, H-4). 13C{ H} NMR (100.6 MHz, CDCl3, 295 K): d −7.8
1
(C-10), 17.3 (C-6/7/8), 18.0 (C-6/7/8), 18.2 (C-6/7/8), 21.4
(C-11), 113.1 (C-13), 127.7 (C-3), 128.7 (C-4), 134.0 (C-2), 134.8
(C-12), 137.7 (C-1). 29Si{ H} NMR (79.5 MHz, CDCl3, 295 K):
1
3
24 H, JHH = 7.9 Hz, H-18), 1.24–1.31 (m, 18 H, H-7, H-12),
d −3.9 (Si-5), 0.3 (Si-9). IR (neat): m 3075m, 2994w, 2970m,
2955m, 2914s, 2876m, 1629s, 1427m, 1418m, 1393m, 1335vw,
1252m, 1192w, 1155m, 1108w, 1032m, 990m, 931m, 893s, 825m,
735vw, 699m, 653vw, 591m, 549vw cm−1. C36H62Si4 (607.23 g
mol−1): calc.: C 71.15, H 10.28; found: C 70.74, H 10.08%.
1.47–1.53 (m, 24 H, H-17), 7.29–7.46 (m, 5 H, H-2, H-3, H-4).
1
13C{ H} NMR (100.6 MHz, CDCl3, 295 K): d −5.1 (C-15), −5.0
(C-10), 5.5 (C-20), 17.3 (C-16), 17.5 (C-17), 17.6 (C-6/7/8),
18.4 (C-11/12/13), 18.5 (C-6/7/8), 18.6 (C-11/12/13), 18.9
(C-11/12/13), 19.0 (C-6/7/8), 25.9 (C-18), 127.6 (C-3), 128.7
1
(C-4), 134.1 (C-2), 138.0 (C-1). 29Si{ H} NMR (79.5 MHz,
CDCl3, 295 K): d −4.0 (Si-5), 1.0 (Si-9), 1.5 (Si-14), 32.2 (Si-19).
IR (neat): m 3065vw, 2918s, 2875s, 1451vw, 1409w, 1336w, 1260s,
1145m, 1083w, 1021m, 943w, 909m, 787s, 745m, 701m, 676m,
538s. C90H194Si22Cl24 (2745.28 g mol−1): calc.: C 39.38, H 7.12;
found: C 39.36, H 7.15%.
PhSi[CH2CH2CH2Si(Me)[CH2CH2CH2Si(Me)Cl)2]2]3
(4).
Same procedure as for compound 1, using 3.34 g (5.50 mmol)
of 3 and 6.45 g (56.1 mmol) of MeHSiCl2. Compound 4 was
obtained as a pale yellow liquid. Yield: 7.14 g (5.50 mmol,
100%). 1H NMR (400.14 MHz, CDCl3, 295 K): d −0.08
3
(s, 9 H, H-10), 0.58 (t, 18 H, JHH = 8.0 Hz, H-8, H-11),
0.74 (s, 18 H, H-15), 0.83 (t, 6 H,3JHH = 8.4 Hz, H-6), 1.13
3
(t, 12 H, JHH = 7.9 Hz, H-13), 1.28–1.36 (m, 6 H, H-7),
PhSi[CH2CH2CH2Si(Me)[CH2CH2CH2Si(Me)[CH2CH2CH2-
SiMe3]2]2]3 (7). Same general procedure as for compound 2,
using 1.92 g (0.70 mmol) of 5 and 7.84 ml (23.5 mmol) of a 3.00
molar solution of methylmagnesium chloride. After work up
and purification by column chomatography compound 7 was
obtained as a viscous colourless oil. Yield: 1.14 g (0.50 mmol,
71%). 1H NMR (400.14 MHz, CDCl3, 295 K): d −0.12 (s,
9 H, H-10), −0.10 (s, 18 H, H-15), −0.04 (s, 108 H, H-20),
0.48–0.56 (m, 78 H, H-8, H-11, H-13, H-16, H-18), 0.82 (t, 6 H,
3JHH = 8.2 Hz, H-6), 1.23–1.36 (m, 42 H, H-7, H-12, H-17),
1.44–1.52 (m, 12 H, H-12), 7.31–7.44 (m, 5 H, H-2, H-3,
1
H-4). 13C{ H} NMR (100.6 MHz, CDCl3, 295 K): d −5.2
(C-10), 5.5 (C-15), 17.2 (C-11/12/13), 17.4 (C-6/7/8), 17.5 (C-
11/12/13), 18.4 (C-6/7/8), 18.6 (C-6/7/8), 25.9 (C-11/12/13),
1
127.8 (C-3), 128.4 (C-4), 134.0 (C-2), 137.7 (C-1). 29Si{ H}
NMR (39.8 MHz, CDCl3, 295 K): d −4.0 (Si-5), 1.5 (Si-9),
32.2 (Si-14). IR (neat): m 3069vw, 2925m, 2878m, 1451vw,
1427m, 1403w, 1339vw, 1261s, 1148m, 1109m, 1021w, 1021w,
943w, 906m, 815s, 787s, 738m, 700m, 536s cm−1. C42H86Si10Cl12
(1297.43 g mol−1): calc.: C 38.88, H 6.68; found: C 38.67,
H 6.49%.
1
7.29–7.43 (m, 5 H, H-2, H-3, H-4). 13C{ H} NMR (100.6 MHz,
CDCl3, 295 K): d −4.9 (C-10), −4.8 (C-15), −1.5 (C-20), 18.5
(C-16/17/18, C-11/12/13), 18.7 (C-16/17/18), 18.8 (C-6/7/8,
C-16/17/18), 18.9 (C-11/12/13), 19.0 (C-11/12/13), 19.1 (C-
6/7/8), 19.2 (C-6/7/8), 127.6 (C-3), 128.6 (C-4), 134.1 (C-2),
1
138.2 (C-1). 29Si{ H} NMR (79.5 MHz, CDCl3, 295 K): d −3.8
(Si-5), 0.8 (Si-9, Si-14), 1.3 (Si-19). IR (neat): m 2959s, 2910s,
2873m, 1447vw, 1412w, 1333vw, 1256s, 1138vw, 1102s, 1082s,
944vw, 909m, 862s, 827s, 800s, 694s, 690m cm−1. MS (FAB):
m/z (relative intensity) 2276.8 (59), [M + Na+]. C114H266Si22
(2255.25 g mol−1): calc.: C 60.76, H 11.89; found: C 60.85, H
11.98%.
PhSi[CH2CH2CH2Si(Me)[CH2CH2CH2Si(Me)(allyl)2]2]3 (5).
Same procedure as for compound 3 using 7.11 g (5.48 mmol) of
compound 4 and 114 ml (92.1 mmol) of a 0.81 molar solution
of allylmagnesium bromide. The reaction product, compound
5 was isolated after chromatography as a colourless viscous
1
oil. Yield: 5.00 g (3.66 mmol, 67%). H NMR (400.14 MHz,
CDCl3, 295 K): d −0.12 (s, 9 H, H-10), −0.04 (s, 18 H, H-15),
3
0.48–0.60 (m, 30 H, H-8, H-11, H-13), 0.83 (t, 6 H, JHH
=
8.4 Hz, H-6), 1.26–1.36 (m, 18 H, H-7, H-12), 1.52 (d, 24 H,
3JHH = 8.2 Hz, H-16), 4.80–4.86 (m, 24 H, H-18),5.70–5.80 (m,
12 H, H-17), 7.30–7.42 (m, 5 H, H-2, H-3, H-4). 13C{ H} NMR
1
(100.6 MHz, CDCl3, 295 K): d −7.7 (C-15), −5.0 (C-10), 17.6 (C-
6/7/8), 17.9 (C-11/12/13), 18.2 (C-11/12/13), 18.5 (C-6/7/8),
18.8 (C-11/12/13), 19.0 (C-6/7/8), 21.5 (C-16), 113.1 (C-18),
PhSi[CH2CH2CH2Si(Me)[CH2CH2CH2Si(Me)[CH2CH2CH2-
Si(Me)(allyl)2]2]2]3 (8). Same procedure as for compound 5,
using 5.02 g (1.83 mmol) of 6 and 92 ml (61.5 mmol) of a
1 3 9 8
D a l t o n T r a n s . , 2 0 0 5 , 1 3 9 4 – 1 4 0 2

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0.67 molar solution of allylmagnesium bromide. After work
up and purification by column chromatography the reaction
product 8 was isolated as a viscous colourless oil. Yield: 3.64 g
(C-21/22/23, C-16/17/18), 19.3 (C-6/7/8), 19.4 (C-6/7/8),
19.5 (C-6/7/8, C-16/17/18), 19.6 (C-16/17/18, C-11/12/13),
19.7 (C-11/12/13, C-11/12/13), 21.9 (C-21/22/23), 127.9
1
1
(1.26 mmol, 69%). H NMR (400.14 MHz, CDCl3, 295 K): d
(C-2/3), 128.0 (C-1), 128.1 (C-2/3), 128.3 (C-4). 29Si{ H} NMR
−0.11 (s, 9 H, H-10), −0.09 (s, 18 H, H-15), −0.02 (s, 36 H,
(79.5 MHz, CDCl3, 295 K): d −3.8 (Si-5), 0.8 (Si-9, Si-14), 1.2
(Si-19), 1.3 (Si-24). IR (neat): m 2952s, 2930s, 2873s, 2790vw,
1449w, 1412m, 1333m, 1247s, 1215w, 1141s, 1080m, 1022m,
979w, 944m, 909s, 862s, 834s, 796s, 756m, 690m, 664w cm−1.
MS (FAB): m/z (relative intensity) 4680.5 (98), [M + Na+].
C234H554Si46 (4660.91 g mol−1): calc.: C 60.25, H 11.98; found: C
60.22, H 11.94%.
H-20), 0.49–0.63 (m, 78 H, H-8, H-11, H-13, H-16, H-18),
3
0.82 (t, 6 H, JHH = 8.1 Hz, H-6), 1.20–1.37 (m, 42 H, H-7,
3
H-12, H-17), 1.54 (d, 48 H, JHH = 8.2 Hz, H-21), 4.81–4.86
(m, 48 H, H-23), 5.71–5.82 (m, 24 H, H-22), 7.30–7.45 (m, 5 H,
1
H-2, H-3, H-4). 13C{ H} NMR (100.6 MHz, CDCl3, 295 K):
d −5.7 (C-20), −5.02 (C-10), −5.0 (C-15), 17.6 (C-6/7/8),
18.0 (C-11/12/13), 18.2 (C-11/12/13), 18.3 (C-16/17/18),
18.5 (C-6/7/8), 18.5 (C-11/12/13), 18.8 (C-16/17/18), 19.0
(C-16/17/18), 19.1 (C-6/7/8), 21.5 (C-21), 113.1 (C-23), 127.6
(C-3), 128.6 (C-4), 134.1 (C-2), 134.8 (C-22), 138.0 (C-1).
1
29Si{ H} NMR (79.5 MHz, CDCl3, 295 K): d −4.1 (Si-5), 0.3
(Si-19), 1.0 (Si-9, Si-14). IR (neat): m 3076m, 2994w, 2970m,
2954m, 2913s, 2876m, 2793vw, 1630s, 1449vw, 1419m, 1333w,
1252s, 1193w, 1153m, 1081vw, 1031m, 990m, 931m, 893s,
814br s, 699m, 654vw, 591m cm−1. C162H314Si22 (2880.16 g
mol−1): calc.: C 67.56, H 10.99; found: C 66.87, H 9.89%.
Si[CH2CH2CH2Si(Ph)Cl2]4 (11). Tetraallylsilane (934 mg,
4.85 mmol), PhHSiCl2 (5.85 g, 33.0 mmol) and 60 ll of
Karstedt’s catalyst were slowly warmed in 15 ml of benzene
until an exothermic reaction set in and the colourless solution
turned bright yellow. The reaction mixture was stirred at 60 ◦C
for 48 h. After cooling to room temperature, the solution was
filtered through 5 cm of silica and the solvent and volatiles were
then removed in vacuo. After leaving under high vacuum for
1.5 h, compound 11 was obtained as a pure pale yellow liquid.
1
Yield: 4.37 g (4.85 mmol, 100%). H NMR (400.14 MHz,
CDCl3, 295 K): d 0.58 (t, 8 H, 3JHH = 5.9 Hz, H-2), 1.35 (t, 8 H,
3JHH = 7.6 Hz, H-4), 1.46–1.77 (m, 8 H, H-3), 7.41–7.71 (m, 20 H,
PhSi[CH2CH2CH2Si(Me)[CH2CH2CH2Si(Me)[CH2CH2CH2-
Si(Me)[CH2CH2CH2Si(Me)Cl2]2]2]2]3 (9). Same general pro-
cedure as for compound 4, using 1.58 g (0.55 mmol) of 8 and
49 g (21.7 mmol) of MeHSiCl2. After work-up compound 9
was isolated as a pale yellow liquid. Yield: 3.10 g (0.55 mmol,
1
H-7, H-8, H-9). 13C{ H} NMR (100.6 MHz, CDCl3, 295 K):
d 15.8 (C-2/3/4), 17.3 (C-2/3/4), 24.9 (C-2/3/4), 128.3 (C-8),
1
131.6 (C-9), 131.7 (C-6), 132.2 (C-7). 29Si{ H} NMR (79.5 MHz,
CDCl3, 295 K): d 1.5 (Si-1), 18.3 (Si-5). IR (neat): m 3073w,
3058vw, 2963m, 2924m, 2876m, 2209w, 1590w, 1429s, 1337 w;
1262m, 1117s, 1020m, 797s, 737m, 694s, 565m, 510m cm−1.
C36H44Si5Cl8 (900.80 g mol−1): calc.: C 47.96, H 4.92; found:
C 47.05, H 4.91%.
1
100%). H NMR (400.13 MHz, CDCl3, 295 K): d −0.12 (s,
9 H, H-10), −0.09 (s, 18 H, H-15), −0.04 (s, 36 H, H-20),
0.51–0.64 (m, 126 H, H-8, H-11, H-13, H-16, H-18, H-21), 0.75
(s, 72 H, H-25), 0.81 (t, 6 H, 3JHH = 8.1 Hz, H-6), 1.16 (t, 48 H,
3JHH = 8.0 Hz, H-23), 1.23–1.33 (m, 42 H, H-7, H-12, H-17),
1.48–1.56 (m, 48 H, H-22), 7.29–7.43 (m, 5 H, H-2, H-3, H-4).
1
13C{ H} NMR (100.6 MHz, CDCl3, 295 K): d −5.1 (C-10),
−5.0 (C-15), −4.9 (C-20), 5.5 (C-25), 17.3 (C-21/22/23), 17.5
(C-21/22/23), 18.0 (C-6/7/8), 18.2 (C-6/7/8), 18.3 (C-6/7/8),
18.5 (C-16/17/18), 18.6 (C-16/17/18), 18.9 (C-16/17/18),
19.0 (C-11/12/12), 19.1 (C-11/12/12), 19.2 (C-11/12/12),
25.9 (C-21/22/23), 127.6 (C-3), 128.6 (C-4), 134.1 (C-2), 138.0
Si[CH2CH2CH2Si(Ph)(allyl)2]4 (12). To a solution of com-
pound 11 (4.36 g, 4.85 mmol) in 10 ml of thf, which was cooled
to –5 ◦C, 116 ml (54.5 mmol) of a 0.47 molar solution of
allylmagnesium bromide were added over a period of 1.5 h. The
reaction mixture was heated under reflux for 48 h, then cooled
to room temperature and slowly poured into a cooled aqueous
solution (100 ml) of NH4Cl. After separation of the organic layer
the aqueous phase was twice extracted with 50 ml of hexane,
the combined organic phases were washed with brine and then
dried over Na2SO4. After removal of the volatiles the residue
was purified by column chromatography (SiO2, 15 cm, hexane–
ethyl acetate 6 : 1) giving compound 12 as a viscous colourless
1
(C-1). 29Si{ H} NMR (79.5 MHz, CDCl3, 295 K): d −4.3
(Si-5), 0.7 (Si-9), 0.8 (Si-14), 1.3 (Si-19), 31.9 (Si-24). IR (neat):
m 2957m, 2917s, 2875s, 2792w, 1451m, 1409m, 1336m, 1260s,
1217m, 1145s, 1084m, 1021m, 979w, 943m, 909s, 817s, 787s,
746s, 700m, 677m, 539s cm−1.
1
PhSi[CH2CH2CH2Si(Me)[CH2CH2CH2Si(Me)[CH2CH2CH2-
Si(Me)[CH2CH2CH2SiMe3]2]2]2]3 (10). Same general pro-
cedure as for compounds 2 and 7, using 2.99 g (0.53 mmol)
of 9 and 11.9 ml (35.6 mmol) of a 3.0 molar solution of
methylmagnesium chloride. After work-up and purification
by column chromatography, compound 10 was obtained as
a viscous, colourless liquid. Yield: 1.72 g (0.37 mmol, 69%).
1H NMR (400.14 MHz, CDCl3, 295 K): d −0.11 (s, 9 H,
H-10), −0.10 (s, 18 H, H-15), −0.09 (s, 36 H, H-20), −0.04 (s,
216 H, H-25), 0.54 (t, 3JHH = 8.3 Hz, 174 H, H-8, H-11, H-13,
oil. Yield: 3.21 g (3.40 mmol, 70%). H NMR (400.14 MHz,
CDCl3, 295 K): d 0.50 (t, 8 H, 3JHH = 8.2 Hz, H-2), 0.87 (t, 8 H,
3JHH = 8.2 Hz, H-4), 1.28–1.39 (m, 8 H, H-3), 1.83 (d, 16 H,
3JHH = 7.6 Hz, H-10), 4.85–4.93 (m, 16 H, H-12), 5.73–5.85 (m,
1
8 H, H-11), 7.34–7.51 (m, 20 H, H-7, H-8, H-9). 13C{ H} NMR
(100.6 MHz, CDCl3, 295 K): d 16.7 (C-2/3/4), 17.4 (C-2/3/4),
18.2 (C-2/3/4), 20.1 (C-10), 113.9 (C-12), 127.7 (C-8), 129.1 (C-
1
9), 134.1 (C-7/11), 134.2 (C-7/11), 136.1 (C-6). 29Si{ H} NMR
(79.5 MHz, CDCl3, 295 K): d −6.5 (Si-5), 0.9 (Si-1). IR (neat): m
3075s, 3053m, 3021m, 2998m, 2972m, 2918m, 2883m, 2125s,
1812w, 1630s, 1486w, 1427s, 1416m, 1399m, 1300w, 1261w,
1191m, 1156m, 1114m, 1038m, 990m, 929m, 896s, 848s, 824m,
786m, 738m, 699s, 660w, 600m, 571w cm−1. C60H84Si5 (945.75 g
mol−1): calc.: C 76.14, H 8.95; found: C 76.12, H 8.80%.
3
H-16, H-18, H-21, H-23), 0.82 (t, 6 H, JHH = 8.2 Hz, H-6),
1.24–1.36 (m, 90 H, H-7, H-12, H-17, H-22), 7.27–7.44 (m, 5 H,
1
H-2, H-3, H-4). 13C{ H} NMR (125.8 MHz, C6D6, 295 K): d
−4.5 (C-25, C-20), −4.4 (C-15, C-10), 19.1 (C-21/22/23), 9.2
D a l t o n T r a n s . , 2 0 0 5 , 1 3 9 4 – 1 4 0 2
1 3 9 9

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stirred for 30 min at that temperature. After stirring for another
45 min while warming the solution to room temperature, the
acid was completely dissolved. After removal of the volatiles
in vacuo, the reaction product was left in a high vacuum (10−5
mbar) for 2.5 h. The yield of the silyltriflates, which are pale
yellow oils was quantitative in all cases.
1
F3CSO3Si[CH2CH2CH2SiMe3]3 (15). H NMR (400.14 MHz,
3
Si[CH2CH2CH2Si(Ph)[CH2CH2CH2Si(Ph)Cl2]2]4 (13). Same
procedure as in the preparation of 11, using 361 mg (0.38 mmol)
of compound 12 and 757 mg (4.28 mmol) of PhHSiCl2. After
work-up, compound 13 was obtained as a pale yellow oil. Yield:
897 mg (0.38 mmol, 100%). H NMR (400.14 MHz, CDCl3,
295 K): d 0.92–1.01 (m, 24 H, H-2, H-10), 1.41–1.46 (m, 24 H,
CDCl3, 295 K): d −0.03 (s, 27 H, H-8), 0.58 (t, 6 H, JHH
=
3
8.2 Hz, H-6), 0.95 (t, 6 H, JHH = 8.2 Hz, H-4), 1.39–1.47
1
(m, 6 H, H-5). 13C{ H} NMR (100.6 MHz, CDCl3, 295 K):
d −1.7 (C-8), 17.0 (C-4/5/6), 18.3 (C-4/5/6), 21.0 (C-4/5/6),
1
1
118.4 (q, C-1). 29Si{ H} NMR (79.5 MHz, CDCl3, 295 K): d
1.3 (Si-7), 37.1 (Si-3). 19F NMR (376.4 MHz, CDCl3, 295 K):
d −76.8 (F-2). IR (neat): m 2953m, 2916m, 2874m, 2205br w,
1394w, 1248s, 1209s,1027s, 946vw, 909m, 862s, 835s, 770vw,
693m, 638m, 577vw, 513w cm−1.
H-4, H-12), 1.60–1.70 (m, 24 H, H-3, H-11), 7.45–7.73 (m, 60 H,
1
H-7, H-8, H-9, H-15, H-16, H-17). 13C{ H} NMR (100.6 MHz,
CDCl3, 295 K): d 15.8 (C-10/11/12), 16.0 (C-2/3/4), 16.3 (C-
2/3/4), 17.3 (C-10/11/12), 24.7 (C-2/3/4, C-10/11/12), 127.9
(C-8), 128.3 (C-16), 129.2 (C-9), 131.6 (C-17), 132.7 (C-6, C-14),
1
133.3 (C-15), 133.9 (C-7). 29Si{ H} NMR (79.5 MHz, CDCl3,
295 K): d −12.1 (Si-1), −4.0 (Si-5), 18.1 (Si-13). IR (neat): m
3072w, 3051vw, 2956m, 2925s, 2878m, 1618w, 1590m, 1487w,
1429s, 1337w, 1259w, 1145m, 1117s, 1028m, 998m, 901m, 793m,
738m, 695s, 564s, 549m, 510s cm−1. C108H132Si13Cl16 (2362.59 g
mol−1): calc.: C 54.86, H 5.63; found: C 54.55, H 5.74%.
F3CSO3Si[CH2CH2CH2Si(Me)[CH2CH2CH2Si(Me)[CH2 -
CH2CH2SiMe3]2]2]3 (16). 1H NMR (300.17 MHz, CDCl3,
295 K): d −0.11 (s, 9 H, H-8), −0.10 (s, 18 H, H-13), −0.05
3
(s, 108 H, H-18), 0.53 (t, 84 H, JHH = 7.9 Hz, H-4, H-6, H-9,
H-11, H-14, H-16), 1.24–1.43 (m, 42 H, H-5, H-10, H-15).
1
13C{ H} NMR (100.6 MHz, CDCl3, 295 K): d −5.1 (C-8), −4.8
(C-13), −1.4 (C-18), 18.5 (C-14/15/16), 18.6 (C-9/10/11), 18.8
(C-14/15/16, C-4/5/6), 19.0 (C-9/10/11), 19.1 (C-9/10/11),
19.2 (C-4/5/6), 19.3 (C-4/5/6), 21.6 (C-14/15/16), 128.6 (q,
1
C-1). 29Si{ H} NMR (79.5 MHz, CDCl3, 295 K): d 0.3 (Si-12),
Si[CH2CH2CH2Si(Ph)[CH2CH2CH2Si(Ph)Me2]2]4 (14). To
a solution of compound 13 (874 mg, 0.37 mmol) in 40 ml of
thf, which was cooled to −5 ◦C, 2.84 ml (8.51 mmol) of a
3.0 molar solution of methylmagnesium chloride were slowly
added. After refluxing for 48 h, the reaction mixture was cooled
to room temperature and then poured into a cooled aqueous
solution (50 ml) of NH4Cl. After separation of the organic
layer, the aqueous phase was twice extracted with 30 ml of
hexane, the combined organic phases were washed with 30 ml
of brine and then dried over Na2SO4. After removal of the
volatiles in vacuo, the residual yellow oil was purified by column
chromatography (SiO2, 15 cm, hexane–ethyl acetate 6 : 1).
Compound 14 was obtained as a viscous colourless liquid. Yield:
482 mg (0.24 mmol, 65%). 1H NMR (400.13 MHz, CDCl3,
0.9 (Si-17), 3.2 (Si-7), 39.7 (Si-3). 19F NMR (376.4 MHz, CDCl3,
295 K): d −77.2 (F-2). IR (neat): m 2952s, 2911s, 2873m, 2791vw,
1448vw, 1411w, 1333vw, 1258s,1248s, 1215vw, 1141m, 1081m,
1081m, 1026m, 981vw, 944w, 910m, 862s, 834s, 807m,750m,
691m cm−1.
F3CSO3Si[CH2CH2CH2Si(Me)[CH2CH2CH2Si(Me)[CH2 -
CH2CH2Si(Me)[CH2CH2CH2SiMe3]2]2]2]3 (17). 1H NMR
(300.17 MHz, CDCl3, 295 K): d −0.12 (s, 9 H, H-8), −0.11
(s, 18 H, H-13), −0.10 (s, 36 H, H-18), −0.05 (s, 216 H, H-23),
0.53 (t, 180 H, 3JHH = 7.9 Hz, H-4, H-6, H-9, H-11, H-14, H-16,
H-19, H-21), 1.24–1.34 (m, 90 H, H-5, H-10, H-15, H-20).
3
295 K): d 0.22 (s, 48 H, H-18), 0.80 (t, 48 H, JHH = 8.0 Hz,
H-2, H-4, H-10, H-12), 1.30–1.39 (m, 24 H, H-3, H-11), 7.33–
1
7.48 (m, 60 H, H-7, H-8, H-9, H-15, H-16, H-17). 13C{ H} NMR
(100.6 MHz, CDCl3, 295 K): d −2.9 (C-18), 17.2 (C-10/11/12),
17.4 (C-2/3/4), 18.3 (C-2/3/4), 18.4 (C-10/11/12), 20.3 (C-
2/3/4), 20.4 (C-10/11/12), 127.6 (C-8), 127.3 (C-16), 128.6 (C-
9), 128.7 (C-17), 133.5 (C-15), 134.0 (C-7), 137.9 (C-6), 139.7
1
13C{ H} NMR (125.7 MHz, CDCl3, 295 K): d −5.1 (C-8),
−5.0 (C-13), −4.9 (C-18), −1.4 (C-23), 18.5 (C-19/20/21), 18.6
(C-14/15/16), 18.7 (C-19/20/21, C-9/10/11), 18.8 (C-4/5/6,
C-4/5/6), 18.9 (C-4/5/6), 19.0 (C-14/15/16, C-14/15/16),
19.1 (C-9/10/11), 19.2 (C-9/10/11), 21.5 (C-19/20/21), 128.7
1
(C-14). 29Si{ H} NMR (79.5 MHz, CDCl3, 295 K): d −22.1 (Si-
1), −4.1 (Si-5/13), −4.0 (Si-5/13). IR (neat): m 3068w, 3046vw,
2961s, 2908m, 2873w, 2851w, 2790vw, 1447w, 1426m, 1412m,
1258s, 1110s, 1023s, 863m, 819s, 728m, 699m, 661m cm−1. MS
(FAB): m/z (relative intensity) 2058.1 (25), [M + Na+].
1
(q, C-1). 29Si{ H} NMR (79.5 MHz, CDCl3, 295 K): d 0.3
(Si-12, Si-17), 0.8 (Si-22), 3.2 (Si-7), 39.8 (Si-3). 19F NMR
(376.5 MHz, CDCl3, 295 K): d −76.7 (F-2). IR (neat): m 2952s,
2911s, 2872m, 2793vw, 1453vw, 1411w, 1333vw, 1248s, 1217vw,
1141m, 1080m, 1025m, 978vw, 943w, 909m, 862s, 834s, 809m,
751m, 691m cm−1.
General procedure for the preparation of the dendritic silyl
triflates
F3CSO3Si[CH2CH2CH2Si(Me)2OSO2CF3]3 (18). To a solu-
tion of compound 2 (242 mg, 0.54 mmol) in 10 ml of toluene,
which was cooled at −40 ◦C, were added dropwise 810 mg
(5.40 mmol) of trifluoromethanesulfonic acid over a period of
10 min. The reaction mixture was warmed to −20 ◦C and stirred
To a solution of the dendritic phenylcarbosilane (0.6 mmol)
in 10 ml of toluene, which was cooled to −40 ◦C, 91.5 mg
(0.61 mmol) of trifluoromethanesulfonic acid were added drop-
wise. The reaction mixture was then warmed to −20 ◦C and
1 4 0 0
D a l t o n T r a n s . , 2 0 0 5 , 1 3 9 4 – 1 4 0 2

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for another 30 min at that temperature. After subsequent stirring
at room temperature for 45 min, all the volatiles were removed in
vacuo yielding compound 19 as a light yellow oil. Yield: 497 mg
(0.54 mmol, 100%). 1H NMR (400.14 MHz, CDCl3, 295 K): d
0.47 (s, 18 H, H-8), 0.98–1.05 (m, 12 H, H-4, H-6), 1.53–1.62 (m,
6 H, H-5). 13C{ H} NMR (100.6 MHz, CDCl3, 295 K): d −1.4
1
Ph2PCH2Si[CH2CH2CH2Si(Me)[CH2CH2CH2Si(Me)[CH2 -
CH2CH2SiMe3]2]2]3 (21). To a solution of Ph3SnCH2PPh2
(65.9 mg, 0.12 mmol) in 2 ml of diethyl ether, which was stirred
at room temperature, were added 64 ll (0.12 mmol) of a 1.8
molar solution of PhLi in cyclohexane–ether with the aid of
a Hamilton syringe. After stirring for 16 h, a colourless solid
had precipitated. The suspension was cooled to −78 ◦C and
13.9 mg (0.12 mmol) of TMEDA and then 279 mg (0.12 mmol)
of compound 16 (dissolved in 2 ml of diethyl ether) were added.
After stirring at that temperature for 30 min, the reaction
mixture was warmed to room temperature and stirred for
another 30 min. After removal of the volatiles in vacuo, the
residue was extracted with 20 ml of hexane. The solvent of
the extract was again removed leaving an oily residue which
was taken up in 1 ml of pentane and subjected to column
chromatography (Al2O3 basic, activity I, eluent: pentane) giving
the reaction product 21 as a colourless oil. Yield: 214 mg
(C-8), 15.4 (C-4/5/6), 17.4 (C-4/5/6), 20.3 (C-4/5/6), 118.3 (q,
1
C-1, C-9). 29Si{ H} NMR (79.5 MHz, CDCl3, 295 K): d 38.7 (Si-
3), 43.1 (Si-7). 19F NMR (376.4 MHz, CDCl3, 295 K): d −76.9
(F-10), −76.6 (F-2). IR (neat): m 2952m, 2927m, 2875m, 2204br
w, 1388s, 1343m, 1247s, 1200 br s, 1156s, 1030s, 967m, 909m,
860m, 807m, 717w, 629s, 550w, 530w, 515w cm−1.
Si[ CH2CH2CH2Si( OSO2CF3 )[ CH2CH2CH2Si( OSO2CF3 ) -
Me2]2]4 (19). To a solution of compound 14 (143 mg,
0.07 mmol) in 5 ml of toluene, which was cooled at −40 ◦C, were
added dropwise 127 mg (0.84 mmol) of trifluoromethanesulfonic
acid. After stirring at −20 ◦C for 30 min and at room temperature
for another 50 min, the solvent and volatiles were removed. After
leaving the reaction product under high vacuum (10−5 mbar)
for 5 h, compound 19 was obtained as a pale yellow oil. Yield:
1
(0.09 mmol, 74%). H NMR (300.17 MHz, CDCl3, 295 K): d
−0.09 (s, 9 H, H-12), −0.08 (s, 18 H, H-17), −0.03 (s, 108 H,
2
H-22), 0.55 (t, 78 H, JHH = 7.5 Hz, H-10, H-13, H-15, H-18,
3
H-20), 0.87 (t, 2 H, JHH = 6.6 Hz, H-8), 1.25–1.41 (m, 42 H,
H-9, H-14, H-19), 1.61 (d, 2 H, 3JHP = 3.5 Hz, H-2), 7.30–7.41
1
84.1 mg (0.07 mmol, 100%). H NMR (300.17 MHz, CDCl3,
1
(m, 10 H, H-5, H-6, H-7). 13C{ H} NMR (100.6 MHz, CDCl3,
295 K): d 0.47 (s, 48 H, H-12), 0.98–1.06 (m, 48 H, H-2, H-4,
1
H-8, H-10), 1.52–1.63 (m, 24 H, H-3, H-9). 13C{ H} NMR
295 K): d −5.0 (C-12), −4.9 (C-17), −1.5 (C-22), 12.5 (d,
JPC = 13.2 Hz, C-2), 18.5 (C-18/19/20, C-13/14/15), 18.7 (C-
18/19/20, C-8/9/10), 18.9 (C-13/14/15), 19.0 (C-13/14/15),
19.1 (C-8/9/10), 19.2 (C-8/9/10), 21.5 (C-18/19/20), 128.3 (d,
JPC = 3.0 Hz, C-6), 132.1 (d, JPC = 18.3 Hz, C-4), 137.2 (C-7),
(75.4 MHz, CDCl3, 295 K): d −1.4 (C-12), 15.4 (C-8/9/10),
17.4 (C-8/9/10, C-2/3/4), 17.9 (C-2/3/4), 19.9 (C-2/3/4),
20.2 (C-8/9/10), 116.2 (q, C-6, C-13). IR (neat): m 2861s,
2925s, 2874s, 2217 br w, 1512vw, 1450m, 1394s, 1260s, 1205s,
1160s, 1107s, 1030s, 976s, 911s, 865s, 822s, 712w, 633s, 570vw,
514m cm−1.
1
140.2 (d, JPC = 11.2 Hz, C-5). 31P{ H} NMR (121.5 MHz,
CDCl3, 295 K): d −26.9 (P-3). IR (neat): m 3060vw, 2952s,
2910s, 2875s, 2795vw, 1480vw, 1451vw, 1432w, 1412w, 1383vw,
1332w, 1247s, 1215vw, 1141m, 1063w, 1141m, 944vw, 909m,
861s, 833s, 737m, 694m cm−1. C121H273Si22P (2377.35 g mol−1):
calc.: C 61.07, H 11.58; found: C 61.08, H 11.75%.
Ph3SnCH2PPh2 (20). To a stirred solution of iodomethyltri-
phenylstannane17 (2.01 g, 4.09 mmol) in 60 ml of toluene, which
was cooled to −55 ◦C, were added 2.57 ml (4.09 mmol) of
a 1.59 molar solution of n-BuLi in hexane. After stirring for
30 min at that temperature 951 mg (8.19 mmol) of TMEDA were
added and the clear solution further cooled to −90 ◦C. At this
temperature 902 mg (4.09 mmol) of Ph2PCl were added dropwise
over a period of 10 min. The yellow solution was then warmed
to −80 ◦C and stirred for another 45 min. After slowly warming
to room temperature, the reaction mixture was hydrolyzed with
15 ml of degassed water, the organic layer was then separated,
twice extracted with 10 ml of degassed water and then dried
over Na2SO4. After removal of all the volatiles in vacuo, the oily
residue was taken up in 3 ml of pentane and subjected to column
chromatography on Al2O3 (basic, activity III) with pentane as
eluent. After collection of the product fraction, all volatiles were
removed in vacuo and the colourless solid residue dried in high
[Ph2PCH2 ]3CCH2OCH2CH2OSi[CH2CH2CH2Si(Me)[CH2 -
CH2CH2Si(Me)[CH2CH2CH2SiMe3]2]2]3 (22). To a solution
of [Ph2PCH2]3CCH2OCH2CH2OH (47.9 mg, 0.07 mmol) in 1 ml
of thf, which was cooled to −60 ◦C, 44 ll (0.07 mmol) of a 1.59
molar solution of n-BuLi in hexane were added with the aid of
a Hamilton syringe. The resulting yellow solution was warmed
to room temperature and stirred for 30 min. After re-cooling
the reaction mixture to −90 ◦C, compound 16 (163 mg,
0.07 mmol) dissolved in 1 ml of thf was added. After stirring for
another 15 min at that temperature, the solution was warmed
to room temperature and stirred for 16 h. After removal of the
volatiles in vacuo, the residue was taken up in 10 ml of toluene
and the colourless precipitate separated by centrifugation.
The solvent of the centrifugate was removed in vacuo and
the reaction product left under high vacuum (10−5 mbar)
for another 5 h to afford compound 22 as a colourless oil.
Yield: 190 mg (0.07 mmol, 95%). 1H NMR (300.17 MHz,
CDCl3, 295 K): d −0.09 (s, 9 H, H-6), −0.08 (s, 18 H, H-11),
1
vacuum to give pure 20. Yield: 1.95 g (3.56 mmol, 87%). H
NMR (300.17 MHz, C6D6, 295 K): d 1.96 (d, 2 H, 2JHP = 2.2 Hz,
H-6), 6.96–7.05 (m, 10 H, H-3, H-4, H-5), 7.32–7.46 (m, 15 H,
1
H-8, H-9, H-10). 13C{ H} NMR (75.4 MHz, CDCl3, 295 K):
3
d 8.7 (d, JPC = 34.2 Hz, C-6), 128.2 (d, JPC = 6.1 Hz, C-4),
−0.03 (s, 108 H, H-16), 0.55 (t, 78 H, JHH = 7.8 Hz, H-4,
128.4 (C-10), 128.9 (C-9), 132.3 (d, JPC = 19.5 Hz, C-2), 136.8
(C-5), 136.9 (C-8), 138.3 (d, JPC = 2.4 Hz, C-7), 141.1 (d, JPC
=
1
14.7 Hz, C-3). 31P{ H} NMR (121.5 MHz, C6D6, 295 K): d
−20.2 (J(119/117SnP) = 50.9 Hz, P-1). C31H27SnP (549.24 g mol−1)
calc.: C 67.85, H 4.96; found: C 68.02, H 5.14%.
D a l t o n T r a n s . , 2 0 0 5 , 1 3 9 4 – 1 4 0 2
1 4 0 1

View Article Online
3
H-7, H-9, H-12, H-14), 0.86 (t, 6 H, JHH = 8.3 Hz, H-2),
3 K. Lorenz, R. Mu¨hlhaupt, H. Frey, U. Rapp and F. J. Mayer-Posner,
Macromolecules, 1995, 28, 6657.
4 N. Hadjichritidis, A. Guyot and L. J. Fetters, Macromolecules, 1978,
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Chem. Commun., 1992, 1400; (b) A. W. van der Made, P. W. N. M.
van Leeuwen, J. C. de Wilde and R. A. C. Brandes, Adv. Mater., 1993,
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Roovers, P. M. Toporowski and L.-L. Zhan, Polym. Prepr. (Am.
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7 A. M. Muzafarov, O. B. Gorbatsevich, E. A. Rebrov, G. M. Ignat’eva,
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8 D. Seyferth, D. Y. Son, A. L. Rheingold and R. L. Ostrander,
Organometallics, 1994, 13, 2682.
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340, 7; (b) W. Uhlig, Chem. Ber., 1992, 125, 47.
10 D. K. Polyakov, G. M. Ignat’eva, E. A. Rebrov, N. G. Vasilenko, S. S.
Sheiko, M. Mo¨ller and A. M. Muzafarov, Vysokomolekul. Soedin.,
Ser. A, Ser. B, 1998, 40, 1421.
2
1.25–1.38 (m, 42 H, H-3, H-8, H-13), 2.44 (d, 6 H, JHP
=
1.7 Hz, H-21), 2.87 (t, 2 H, 3JHH = 4.2 Hz, H-17/18), 3.30–3.34
(m, 4 H, H-17/18, H-19), 7.15–7.31 (m, 30 H, H-aromat.).
13C{ H} NMR (75.5 MHz, CDCl3, 295 K): d −5.0 (C-6), −4.9
1
(C-11), −1.4 (C-16), 18.5 (C-12/13/14), 18.6 (C-7/8/9), 18.7
(C-12/13/14), 18.8 (C-2/3/4), 18.9 (C-7/8/9), 19.0 (C-7/8/9),
19.1 (C-2/3/4), 19.2 (C-2/3/4), 21.5 (C-12/13/14), 38.3–39.0
(m, C-21), 42.4–42.9 (m, C-20), 61.1 (C-17/18), 71.4 (C-17/18),
76.9 (C-19), 128.3 (d, JPC = 7.3 Hz, C-aromat.), 132.9 (d, JPC
=
20.7 Hz, C-aromat.), 133.0 (C-aromat.), 139.5 (d, JPC = 11.3 Hz,
Cquarta¨r-aromat.). 31P{ H} NMR (121.5 MHz, CDCl3, 295 K):
1
d −26.6 (P-22). 29Si{ H} NMR (79.5 MHz, CDCl3, 295 K): d
1
0.4 (Si-15), 0.9 (Si-10), 3.2 (Si-5), 15.3 (Si-1). IR (neat): m 2952s,
2910s, 2873s, 2792vw, 1450vw, 1233w, 1247s, 1215w, 1141m,
1082m, 1024m, 978w, 943w, 909m, 862s, 834s, 822s, 802m,
691m cm−1. C151H303Si22O2P3 (2861.87 g mol−1): calc.: C 63.37,
H 10.67; found: C 62.54, H 11.23%.
11 A. Boudin, C. Chuit, C. Genevieve, J. P. Corriu and C. Reye, Angew.
Chem., 1986, 98, 474.
Acknowledgements
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We thank the Deutsche Forschungsgemeinschaft for funding
and Wacker Chemie AG for generous gifts of basic chemicals.
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1 4 0 2
D a l t o n T r a n s . , 2 0 0 5 , 1 3 9 4 – 1 4 0 2