The fixation of bis(2-pyridylimino)isoindolato (BPI) ligands to dendritic carbosilanes

Article abstract of DOI:10.1039/b501070e

Bis(2-pyridylimmo)isoindolato (BPI) ligands, containing an alkynyl linker unit which allows their fixation to carbosilane dendrimers and dendrons, were synthesized by reaction of 4-nitrophthalodinitrile with 4-butynol giving the phthalodinitrile derivativ

Full text of DOI:10.1039/b501070e

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F U L L P A P E R
The fixation of bis(2-pyridylimino)isoindolato (BPI) ligands to
dendritic carbosilanes
Markus B. Meder, Isabelle Haller and Lutz H. Gade*
Anorganisch-Chemisches Institut, Universita¨t Heidelberg, Im Neuenheimer Feld 270, 69120
Heidelberg, Germany. E-mail: lutz.gade@uni-hd.de
Received 21st January 2005, Accepted 3rd March 2005
First published as an Advance Article on the web 15th March 2005
Bis(2-pyridylimino)isoindolato (BPI) ligands, containing an alkynyl linker unit which allows their fixation to
carbosilane dendrimers and dendrons, were synthesized by reaction of 4-nitrophthalodinitrile with 4-butynol giving
the phthalodinitrile derivative 1 containing the linker. These were subsequently reacted with two molar equivalents of
2-amino-4-methylpyridine and 2-amino-4-tbutylpyridine yielding the respective BPI protioligands 2a and 2b.
Lithiation with LDA and reaction with Si–Cl or Si–OTf (OTf = triflate) end groups in core or peripheral positions of
dendritic carbosilanes gave the endodendrally and expdendrally functionalized dendrimers. Among these the first
and second generation dendrimers [G-1]8-exo-4-[C≡CCH2CH2O]-10-MeBPI (8), [G-1]12-exo-4-[C≡CCH2CH2O]-
10-MeBPI (9) and [G-2]16-exo-4-[C≡CCH2CH2O]-10-MeBPI (10) were synthesized and fully characterized. The
functional dendrimers were metallated by reaction with [(PhCN)2PdCl2] in dichloromethane to give the
corresponding pallada-dendrimers.
Introduction
Results and discussion
Since the first reports of the dendrimer fixation of molecular
catalysts,1 a variety of ligands and catalytically active complexes
have been immobilized on the inside and outside of dendritic
polymers.2 The aim of these research activities has been the
development of catalytic phases which combine the virtues of
homogeneous catalysis (high activity and selectivity, directed
catalyst design) with those of heterogeneous catalysts (e.g.
facile catalyst separation and recycling).3 In principle, the
position of catalytic sites in high density at the periphery of
dendritic macromolecules may significantly alter the activity
and selectivity in comparison with the respective mononuclear
molecular catalysts.4
Leaching of the metal is a major practical problem, regardless
of the method of catalyst fixation and the nature of the support
material.5 This may be suppressed to various degrees by using
polydentate ligands which form thermally and kinetically stable
complexes with the catalyst metal.
Synthesis of BPI-ligands (2a and 2b) containing an
alkynyl-linker
Linker units are conveniently attached to the isoindole part of
the bis(pyridylimino)isoindole protioligands (BPI’s), however,
their fixation has to be carried out at the phthalodinitrile level
and prior to the assembly of the tricoordinate ligands. This
was first noted by Siegl and coworkers7 and Brewis et al. have
shown in their synthesis of phthalocyanines at the core of
polyarylether dendrimers,11 that the coupling of the dendrons
with the ligand or dendrimer core is readily achieved by the nu-
cleophilic substitution of 4-nitrophthalodinitrile with the in situ
generated alcoholates. Reaction of 4-nitrophthalodinitrile with
4-butynol cleanly gave the “tagged” phthalodinitrile derivative
1 (Scheme 1).
We have recently begun to investigate the catalytic activity
of palladium complexes containing derivatives of the well
established bis(2-pyridylimino)isoindolate (BPI) ligands (A),6
which have been extensively studied previously in oxidation
catalysis induced by the middle and late transition metals.7–10 The
novel BPI–palladium compounds have proved to be a promising
new non-phosphine based class of molecular hydrogenation
catalysts for alkenes, operating at ambient hydrogen pressure.6
In this paper we report the synthesis of BPI derivatives
containing an alkynyl linker unit which allows their fixation
to carbosilane dendrimers and dendrons. These are metallated
to give the corresponding pallada-dendrimers.
Scheme 1 Synthesis of a BPI ligand with an alkynyl linker for the
immobilization on carbosilane dendrimers.
The synthesis of the BPI ligands derived from 1 was
achieved by reaction with two molar equivalents of 2-amino-4-
methylpyridine and 2-amino-4-tbutylpyridine in the presence of
CaCl2 in hexanol under reflux for 20 h to give the protioligands
2a and 2b as yellow microcrystalline solids.
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
D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5
1 4 0 3
©

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Silylation of the alkynyl-functionalized BPI-ligands and
synthesis of their palladium(II) complexes
equivalents of base per BPI protioligand were required, since de-
protonation of the isoindole-NH function preceded the H-abs-
traction from the alkynyl unit. The result was a doubly lithiated
species which, due to the greater nucleophilicity of the acetylide
anion selectively gave the desired Si–C-bonded products.
The reaction of acetylide anions with chlorosilanes as dendrimer
end groups has been reported by Kim et al.12 In their work, the
alkynyl reagents were employed in excess and then removed
in vacuo after reprotonation. Following this approach, pheny-
lacetylene functionalized dendrimers containing relatively inert
Si–C bonds were obtained. We took up this strategy of alkynyl
fixation for the attachment of the BPI-linker units described
above to carbosilane dendrimers, using LDA as the base for
the deprotonation of the alkynyl linkers. In all cases two molar
t
A first successful trial with BuMe2SiCl, giving the silylated
ligand 3 was followed up by the corresponding reaction with
a dendritic triflate substituted carbosilane 5 to yield a core
functionalized carbosilane dendrimer 6 (Scheme 2). The triflato
derivative 5 was conveniently generated from the dendritic
phenylsilane 4 by acidolytic treatment with triflic acid (see
Scheme 3).13 This transformation has been known for some
Scheme 2 Metallation of the BPI-linker unit 2a with LDA in thf and subsequent silylation. In the synthesis of 6 this amounts to the core fixation of
the protioligand to a dendritic carbosilane.
Scheme 3 Synthesis of the triflato carbosilane 5 by acidolysis of the “dummy” phenyl group at the core of 4. This activates the core position in
carbosilane dendrimers and allows the subsequent functionalization.
1 4 0 4
D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5

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Scheme 4 Fixation of the ligand-linker units 2a,b to the chain ends of a zeroth generation carbosilane dendrimer.
time14 and, very recently, has been applied by us to carbosi-
lane dendrimer chemistry.13 The endodendrally functionalized
dendrimer 6 was characterized by 1H, 13C and 29Si NMR
spectroscopy as well as a FAB mass spectrum which displays
its molecular ion at m/z = 1670.1.
Following an analogous synthetic protocol as described
above the BPI-functionalized first and second genera-
tion dendrimers [G-1]8-exo-4-[C≡CCH2CH2O]-10-MeBPI (8),
[G-1]12-exo-4-[C≡CCH2CH2O]-10-MeBPI (9) and [G-2]16-exo-4-
[C≡CCH2CH2O]-10-MeBPI (10) were synthesized (Scheme 5).
The high molecular symmetry of the first generation car-
bosilane [G-1]8-exo-4-[C≡CCH2CH2O]-10-MeBPI (8) (Fig. 1) is
Fixation of the alkynyl-functionalized BPI-ligands at the
periphery of carbosilane dendrimers
1
reflected in the simplicity of the signal patterns in its H and
13C NMR spectra. As expected, three signals are observed in
the 29Si NMR spectrum, the resonance at −17.7 ppm being
again characteristic for the 29Si nuclei adjacent to the C≡C-
triple bond. The molecular ion peak was found at m/z = 4326.7
in the negative ion FAB mass spectrum and is associated with
the dianion peak at m/z = 2660.8.
Having shown the feasibility of an “endodendral” fixation of the
BPI ligand to dendritic carbosilanes we attempted the analo-
gous functionalization of dendrimer end-groups (“exodendral
fixation”). In order to avoid the formation of complex product
mixtures a complete conversion of the Si–Cl end groups and thus
an optimization of the coupling reaction were essential. Using
the lithiated alkynyl-BPI derivatives 2a and 2b described in the
previous section we first synthesized the two zeroth generation
BPI functionalized dendrimers 7a and 7b (Scheme 4).
The complete functionalization of the silyl end groups is
reflected in the observation of only a single singlet proton
resonance for the Si(CH3)2-groups at 0.14 ppm, of the triplet
at 2.74 ppm assigned to the methylene group adjacent to the
C≡C triple bond as well as a single set of 13C NMR resonances
for the carbosilane core and the attached ligands. In the 29Si-
NMR spectra two resonances at −17.5 ppm (periphery) and
1.0 ppm (core) are observed while the identity of the reaction
products [G-0]4-exo-4-[C≡CCH2CH2O]-10-MeBPI (7a) and [G-
0]4-exo-4-[C≡CCH2CH2O]-10-tBuBPI (7b) was confirmed by the
detection of the molecular ion peaks in the FAB mass spectra at
m/z = 2006.6 and 2344.4, respectively.
The NMR data of the other functionalized first generation
dendrimer [G-1]12-exo-4-[C≡CCH2CH2O]-10-MeBPI (9) are very
similar to those of compound 8. However, due to an accidental
coincidence of the 29Si NMR resonances of the inner Si nuclei
only two signals at 17 ppm and 1 ppm are observed. The
complete exodendral functionalization was confirmed by a
MALDI-TOF spectrum displaying the molecular ion peak at
m/z = 6244.7 and the absence of mass peaks due to incompletely
converted species.
The synthesis of the exodendrally functionalized correspond-
ing second generation dendrimer was achieved by reaction of
the chlorosilane [G-2]16-exo-Cl with the lithiated BPI derivative 2a
giving [G-2]16-exo-4-[C≡CCH2CH2O]-10-MeBPI (10). The simple
pattern of signals in the 1H, 13C and 29Si NMR spectra of
the highly symmetrical functionalized dendrimer (Fig. 2) are
consistent with the complete conversion of the chlorosilane
D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5
1 4 0 5

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Scheme 5 Exodendral fixation of the ligand-linker unit 2a to first and second generation carbosilane dendrimers.
precursor. This formulation was substantiated by the observa-
tion of the molecular ion peak at m/z = 8963.2 in the MALDI-
TOF mass spectrum and the absence of peaks attributable to
defect structures.
[C≡CCH2CH2O]-10-tBuBPIPdCl (13b) was found as expected
at m/z = 2869.7.
Reaction of the first generation dendrimer [G-1]8-exo-4-
[C≡CCH2CH2O]-10-MeBPI (8) with [(PhCN)2PdCl2] gave the
eightfold metallated product 14 (Fig. 3). The low yield of the
isolated product of 25% is due to the loss incurred in the re-
peated extractions in order to remove the ammonium salts which
strongly adhere to the dendrimer.
Metallation of the functionalized dendrimers with palladium(II)
In view of the established catalytic hydrogenation activity of
BPI–palladium complexes6 and the facile accessibility of the
square planar Pd and Pt complexes the palladation of the PBI-
functionalized dendrimers was the principal aim of this work.
In a first trial reaction of the simple silylated compound 3 with
[(PhCN)2PdCl2] in dichloromethane the Pd-complex 11 was
obtained in high yield (Scheme 6). The conversion was clean
and there was no indication of a partial cleavage of the Si–C(sp)
bond.
Similarly, the metallation of the “endodendrally”
functionalized second generation dendrimer [G-2]1-endo-4-
[C≡CCH2CH2O]-10-MeBPI (6) employing the same reaction
conditions gave the second generation endodendral palladium
complex [G-2]1-endo-4-[C≡CCH2CH2O]-10-MeBPIPdCl (12).
Its structure was established by the 1H, 13C and 29Si NMR
spectroscopic data and the observation of the molecular ion
peak at m/z = 1774.9 in the negative ion FAB mass spectrum.
In the same way as for the systems discussed above, the
palladation of the two “exodendrally” functionalized [G-0]-
dendrimers 7a,b gave the corresponding metalladendrimers
13a,b (Scheme 7). A convenient probe for the metallation is the
low field shift of the a-pyridyl protons in the BPI units from 8.5
to 9.5 ppm and the observation of a single set of resonances in
the 13C NMR spectrum. In the positive ion FAB mass spectrum
of [G-0]4-exo-4-[C≡CCH2CH2O]-10-MeBPIPdCl (13a) the base
peak was observed at m/z = 2534.5 which corresponds to the
fragment [M − Cl−]+ while the molecular ion peak of [G-0]4-exo-4-
1
The H, 13C and 29Si NMR spectra of dendrimer 14 display
similarly simple signal patterns as those of 13a,b indicating
complete metallation. The peak at m/z = 5419.9 observed
in the MALDI-TOF mass spectrum of 14 corresponds to
the monocation [M − Cl−]+, thus establishing the identity of
the pallada-dendrimer. All attempts to metallate the higher
BPI-functionalized dendrimers [G-1]12-exo-4-[C≡CCH2CH2O]-
10-MeBPI (9 and [G-2]16-exo-4-[C≡CCH2CH2O]-10-MeBPI (10)
in dichloromethane only gave insoluble materials which eluded
adequate characterization.
Conclusions
We have developed a new class of BPI-ligands containing
alkynyl linker units which allow their convenient grafting to
carbosilane dendrimers both in endo- and exodendral positions.
The choice of a carbon nucleophile and thus the formation of
Si–C bonds between the carbosilane and the ligand-linker unit
leads to kinetically inert functionalized dendrimers which may
be metallated by reaction with palladium(II) complexes. The
approach based on alkynyl linkers presented in this work may
be generally applied in the immobilization of metal complexes, as
we have previously shown for polydentate phosphines.15 Current
and future work will be devoted to the investigation of the
catalytic properties of these systems with the aim of extending
1 4 0 6
D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5

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Fig. 1 Structure of the functionalized first generation carbosilane dendrimer 8.
our previous systematic investigation of “dendrimer effects” in
hydrogenation and C–C coupling catalysis.4,16
heated to 50 ◦C. To this mixture 3-butynol (0.81 g = 11.5 mmol)
was added over a period of 30 min. After stirring for 20 h,
the reaction mixture was cooled to room temperature. Upon
addition of water, the solid reaction product precipitated. It was
washed with 3 × 20 ml of water, re-dissolved in toluene and
the solution dried over MgSO4. Evaporation of the solvent gave
pure 4-(3-butynoxy)phthalodinitrile (1) as a colourless solid.
Yield: 0.93 g (4.73 mmol, 82%). Mp: 97 ◦C. 1H-NMR
(400.16 MHz, CDCl3, 298 K): d = 2.04 (t, 4JHH = 2.6 Hz, 1 H,
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–
3
4
˚
≡CH), 2.71 (dt, JHH = 6.7 Hz, JHH = 2.6 Hz, 2 H, ≡CCH2),
thaw” cycles and stored over 4-A molecular sieves. Solids were
3
3
4.16 (t, JHH = 6.7 Hz, 2 H, OCH2), 7.19 (dd, JHH = 8.8 Hz,
4JHH = 2.5 Hz, 1 H, H(5)), 7.26 (d, 4JHH = 2.5 Hz, 1 H, H(3)),
separated from suspensions by filtration through dried Celite
1
or by centrifugation. The H, 13C and 29Si NMR spectra were
7.70 (d, 3JHH = 8.8 Hz, 1 H, H(6)). { H} C-NMR (100.6 MHz,
CDCl3, 295 K): d = 19.3 (≡CCH2), 67.0 (OCH2), 70.7 (≡CH),
79.3 (C≡CH), 107.5 (C-1), 115.2, 115.6 (C-7), 117.4 (C-2), 119.6
(C-3), 120.1 (C-5), 135.3 (C-6), 161.6 (C-4). IR (KBr): m [cm−1] =
3306 (m), 3114 (w), 3083 (w), 3046 (w), 2956 (m), 2232 (s), 2127
(w), 1597 (s), 1507 (m), 1490 (w), 1473 (m), 1426 (w), 1413 (w),
1324 (s), 1262 (s), 1211 (w), 1180 (w), 1088 (m), 1021 (s), 929 (w),
868 (m), 856 (m), 739 (w), 645 (s). C12H8N2O (196.21 g mol−1):
calcd.: C 73.46, H 4.11, N 14.28; found: C 73.18, H 4.00, N
14.19.
1
13
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). Infrared spectra were recorded on a
Nicolet Magna IRTM 750 spectrometer. Elemental analyses
were carried out by the microanalytical service at the chem-
istry department at Strasbourg. 2-Amino-4-tert-butylpyridine,17
[(PhCN)2PdCl2]18 and the chlorosilyl functionalized carbosilane
dendrimers19 were prepared according to published procedures.
All other chemicals used as starting materials were obtained
commercially and used without further purification.
Preparation of 4-(3-butynoxy)phthalodinitrile (1)
Solid K2CO3 (1.59 g = 11.5 mmol) was added to a solution
of 4-nitrophthalodinitrile dissolved in DMF (15 ml) which was
D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5
1 4 0 7

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Fig. 2 Structure of the functionalized second generation carbosilane dendrimer 10.
Preparation of 4-(3-butynoxy)-10-MeBPI (2a)
4-(3-Butynoxy)phthalodinitrile (1) (1.00 g = 5.10 mmol), 2-
amino-4-methylpyridine (1.37 g = 12.7 mmol) and CaCl2
(0.16 g = 1.36 mmol) were dissolved in 1-hexanol (50 ml) and
heated under reflux for 72 h. Upon subsequent cooling to room
temperature, the solid reaction product precipitated and was
isolated by filtration. After washing the precipitate with 3 ×
50 ml of water, it was dried over P4O10 giving pure 2a as a yellow
solid.
Yield: 1.35 g (3.42 mmol, 67%). Mp: 180 ◦C. 1H-NMR
(300.17 MHz, CDCl3, 298 K): d = 2.06 (t, 4JHH = 2.8 Hz, 1 H,
Preparation of 4-(3-butynoxy)-10-tBuBPI (2b)
3
4
≡CH), 2.38 (s, 6 H, 10-CH3), 2.72 (dt, JHH = 6.9 Hz, JHH
=
2.8 Hz, 2 H, ≡CCH2–), 4.25 (t, 3JHH = 6.9 Hz, 2 H, –OCH2–),
4-(3-Butynoxy)phthalodinitrile (1) (1.00 g = 5.10 mmol), 2-
amino-4-tbutylpyridine (1.60 g = 10.6 mmol) and CaCl2
(0.16 g = 1.36 mmol) were dissolved in 1-hexanol (50 ml) and
heated under reflux for 36 h. Upon subsequent cooling to room
temperature, the solid reaction product precipitated and was
isolated by filtration. After washing the precipitate with 3 ×
50 ml of water it was dried over P4O10 giving pure 2b as a yellow
solid.
3
4
6.92 (m, 2 H, H(11)), 7.15 (dd, JHH = 8.2 Hz, JHH = 2.3 Hz,
1 H, H(5)), 7.28 (s, br, 2 H, H(9)), 7.52 (d, 4JHH = 2.3 Hz, 1 H,
H(3)), 7.98 (d, 3JHH = 8.2 Hz, 1 H, H(6)), 8.43 (m, 2 H, 1H(2)),
1
13
13.85 (s, br, 1 H, NH). { H} C-NMR (100.6 MHz, CDCl3,
298 K): d = 19.8 (≡CCH2–), 21.2 (10-CH3), 66.8 (–OCH2), 70.5
(–C≡CH), 80.3 (–C≡CH), 106.9 (C-3), 120.0 (C-5), 121.5/121.7
(C-9), 123.6/123.8 (C-11), 124.3 (C-6), 128.5 (C-1), 138.1 (C-2),
147.6/147.7 (C-12), 149.5 (C-10), 153.7 (C-7), 160.4 (C-8), 162.1
(C-4). IR (KBr): m [cm−1] = 3219 (m), 3049 (w), 2922 (w), 2130
(vw), 1627 (s), 1586 (s), 1540 (m), 1489 (m), 1465 (m), 1399 (w),
1358 (m), 1330 (m), 1291 (vw), 1274 (w), 1235 (s), 1191 (w),
1166 (m), 1151 (w), 1114 (m), 1041 (s), 936 (w), 816 (m), 718
(m), 681 (w). C24H21N5O (395.46 g.mol−1): calcd.: C 72.89, H
5.35, N 17.71; found: C 72.66, H 5.54, N 17.31.
Yield: 1.35 g (3.42 mmol, 67%). Mp: 199 ◦C. 1H-NMR
(300.17 MHz, CDCl3, 298 K): d = 1.34 (2·s, total of 18 H, 10-
C(CH3)3), 2.06 (t, 4JHH = 2.6 Hz, 1 H, ≡CH), 2.74 (dt, 3JHH
=
7.0 Hz, 4JHH = 2.6 Hz, 2 H, ≡CCH2–), 4.26 (t, 3JHH = 7.0 Hz,
3
2 H, –OCH2–), 7.08 (m, 2 H, H(11)), 7.13 (dd, JHH = 8.4 Hz,
4JHH = 2.2 Hz, 1 H, H(5)), 7.42 (m, br, 2 H, H(9)), 7.54 (d, 4JHH
=
2.2 Hz, 1 H, H(3)), 7.94 (d, 3JHH = 8.4 Hz, 1 H, H(6)), 8.48 (m,
1 4 0 8
D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5

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Scheme 6 Metallation of the protioligands 3 and 6 by reaction with [PdCl2(PhCN)2].
0.91 (s, 9 H, –SiC(CH3)3), 2.35 (s, 6 H, 10-CH3), 2.76 (t, 3JHH
=
6.7 Hz, 2 H, ≡CCH2–), 4.21 (t, 3JHH = 6.7 Hz, 2 H, –OCH2–),
6.90 (m, 2 H, H(11)), 7.13 (m, 1 H, H(5)), 7.23 (s, br, 2 H, H(9)),
7.50 (d, 4JHH = 2.0 Hz, 1 H, H(3)), 7.91 (d, 3JHH = 8.4 Hz, 1 H,
1
13
2 H, 1H(2)), 13.84 (s, br, 1 H, NH). { H} C-NMR (75.5 MHz,
CDCl3, 298 K): d = 19.5 (≡CCH2–), 30.5 (10-C(CH3)3), 34.8
(10-C(CH3)3), 66.5 (OCH2), 70.1 (≡CH), 80.5 (–C≡CH), 106.5
(C-3), 117.4/117.6 (C-9), 119.7 (C-5), 119.8/119.9 (C-11), 123.8
(C-6), 128.4 (C-1), 137.9 (C-2), 147.5/147.6 (C-12), 153.5 (C-
7), 160.5/160.6 (C-8), 161.9 (C-4), 162.3 (C-10). IR (KBr): m
[cm−1] = 3312 (m), 2963 (s), 2126 (vw), 1633 (s), 1590 (s), 1534
(s), 1488 (m), 1466 (m), 1400 (m), 1365 (m), 1353 (m), 1326 (w),
1285 (m), 1264 (m), 1225 (m), 1107 (w), 1046 (m), 926 (vw), 894
(m), 859 (vw), 835 (m), 785 (vw), 719 (m), 622 (w), 495 (vw).
C30H33N5O (479.63 g.mol−1): calcd.: C 75.13, H 6.94, N 14.60;
found: C 75.03, H 7.08, N 14.56.
1
13
H(6)), 8.44 (m, 2 H, 1H(2)), 12.61 (s, br, 1 H, NH). { H} C-
NMR (100.6 MHz, CDCl3, 298 K): d = −4.5 (–Si(CH3)2–), 16.5
(SiC(CH3)3), 20.9 (10-CH3), 21.0 (≡CCH2–), 26.0 (SiC(CH3)3),
66.7 (–OCH2–), 84.9 (CH2C≡C), 102.7 (–C≡CSi), 106.5 (C-3),
119.8 (C-5), 121.2/121.4 (C-9), 123.4/123.5 (C-11), 123.9 (C-6),
128.2 (C-1), 137.9 (C-2), 147.4 (C-12), 149.3 (C-10), 153.7 (C-
1
29
7), 160.3/160.4 (C-8), 161.9 (C-4). { H} Si-NMR (39.8 MHz,
CDCl3, 298 K): d = −8.6 (–Si(CH3)2–). IR (KBr): m [cm−1] =
2954 (m), 2924 (m), 2179 (m), 1652 (m), 1635 (m), 1590 (s), 1489
(m), 1465 (m), 1386 (w), 1260 (m), 1191 (vw), 1105 (m), 1037
(w), 821 (m), 697 (m), 618 (w). C30H35N5OSi (509.72 g.mol−1):
calcd.: C 70.69, H 6.92, N 13.74; found: C 71.02, H 7.36,
N 14.11.
Preparation of 4-(tBuSi(CH3)2C≡CCH2CH2O–)-10-MeBPI (3)
A solution of LDA in thf (2 M) (0.25 ml = 0.23 mmol) was slowly
added to a solution of 4-(3-butynoxy)-10-MeBPI (2a) (91.0 mg =
0.23 mmol) in thf (10 ml), which was cooled to −80 ◦C. The mix-
ture was warmed to −40 ◦C and then re-cooled to −80 ◦C. After
addition of tBuSi(CH3)2Cl (35.0 mg = 0.23 mmol) the reaction
mixture was warmed to room temperature and then stirred for
another 16 h. After removal of the volatiles in vacuo, the residue
was washed with 3 × 10 ml of water and then recrystallized from
CH3Cl/n-hexane giving 3 as a yellow solid.
Preparation of PhSi[(CH2)3Si[(CH2)3SiMe3]3]3 (4)
To a solution of 1.24 g (1.82 mmol) of IV in 60 ml of thf, which
was cooled to −5 ◦C, were added 7.84 ml (23.5 mmol) of a 3.00
molar solution of methylmagnesium chloride over a period of
1.5 h. The reaction mixture was refluxed for 17 h and then poured
into an ice cold aqueous solution of NH4Cl (100 ml). After
separation of the organic phase, the aqueous solution was twice
extracted with 50 ml of hexane. The combined organic phases
were washed with 50 ml of brine and then dried over Na2SO4.
After removal of the solvent in vacuo, the residue was purified
◦
1
Yield: 87.0 mg (0.17 mmol, 74%). Mp: 184 C. H-NMR
(300.17 MHz, CDCl3, 298 K): d = −0.04 (s, 6 H, Si(CH3)2),
D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5
1 4 0 9

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Scheme 7 Metallation of the zeroth generation dendrimers 7a,b by reaction with [PdCl2(PhCN)2].
1
13
by column chromatography (silica, hexane/ethyl acetate 6 : 1).
14-1H(6)), 1.30 (m, 24 H, 12-1H(5)). { H} C-NMR (75.5 MHz,
CDCl3, 298 K): d = 1.5 (C17), 17.5 (C11–14), 18.6 (C13–16), 21.7
Compound 4 was obtained as a colourless viscous oil. Yield:
1
1
29
59%. H-NMR (300.17 MHz, CDCl3, 298 K): d = −0.02 (s,
(C12–15), 118,4 (CF3). { H} Si-NMR (79.5 MHz, CDCl3, 298 K):
d = 40.2 (CF3S(O)2–OSi), 0.8 (Si–Me3). 0.6 (CH2–Si–CH2). IR
(KBr) [cm−1] = 1247 (m, C–F), 1350 (S = O). C64H153O3SSi13F3
(1425.09 g mol−1): calcd.: C 53,94, H 10,82; found: C 53.20, H
11.31.
81 H, 1H(7)), 0.55 (m, 48 H, 11-13-14-1H(6)), 1.32 (m, 24 H, 12-
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13
1H(5)), 7.32–7,47 (m, H(5), HPh). { H} C-NMR (75.5 MHz,
CDCl3, 298 K): d = −1.4 (C17), 18.6 and 17.5 (C11,13,14,16), 21.7
1
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(C12, C15), 127.7, 128.7, 134.0; 137.8 (C-arom.). { H} Si-NMR
(79.5 MHz, CDCl3, 298 K): d = −4.1 (Si–Ph), 0.6 (CH2–Si–
CH2), 0.5 (Si–Me3). IR (KBr) = 2952 (s), 2911 (s), 2874 (s), 698
(m) cm−1. C69H158Si13 (1353 g.mol−1): calcd.: C 61,25, H 11,77;
found: C 61,29, H 11,83.
Preparation of [G-2]1-endo-4-[C≡CCH2CH2O]-10-MeBPI (6)
A solution of LDA in thf (2 M) (86.3 ll = 0.17 mmol) was
slowly added to a solution of 4-(3-butynoxy)-10-MeBPI (2a)
(60.0 mg = 86.3 lmol) in thf (15 ml), which was cooled
to −80 ◦C. The mixture was warmed to −40 ◦C and then
re-cooled to −80 ◦C. After the addition of [G-2]1-endo-SiOTf
(0.12 g = 86.3 lmol) the reaction mixture was warmed to room
temperature and then stirred for another 16 h. After removal of
the volatiles in vacuo, the residue was washed with 3 × 10 ml
of water and then purified by column chromatography (silica,
elution with pentane/CH2Cl2/Et2O).
Preparation of (TfO)Si[(CH2)3Si[(CH2)3SiMe3]3]3 (5)
To a solution of 4 0,86 g (1,91 mmol) in 5 ml of toluene, which
was cooled to −40 ◦C, were added 0,17 mL (1,91 mmol) of
trifluoromethanesulfonic acid over a period of 10 min. The
reaction mixture was stirred at −20 ◦C for 30 min and then
at room temperature for another 55 min. After removal of
the volatiles under high vacuum, compound 5 was obtained in
quantitative yield as a pale yellow oil. 1H-NMR (300.17 MHz,
CDCl3, 298 K): d = −0.03 (s, 81 H, SiMe3). 0.56 (m, 54 H, 11-13-
Yield: 0.10 g (61.3 lmol, 71%). 1H-NMR (300.17 MHz,
CDCl3, 298 K): d = −0.03 (s, 81 H, H(k)), 0.56 (m, br, 48 H, H(e),
1 4 1 0
D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5

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Fig. 3 Structure of the first generation pallada-dendrimer 8.
H(g), H(h), H(j)), 1.33 (m, 24 H, H(f), H(i)), 2.39 (s, br, 6 H, 10-
Preparation of [G-0]4-exo-4-[C≡CCH2CH2O]-10-MeBPI (7a)
CH3), 2.78 (t, 3JHH = 7.3 Hz, 2 H, H(b)), 4.23 (t, 3JHH = 7.3 Hz,
A solution of LDA in thf (2 M) (1.77 ml = 3.54 mmol) was slowly
added to a solution of 4-(3-butynoxy)-10-MeBPI (2a) (0.70 g =
1.77 mmol) in thf (80 ml), which was cooled to −80 ◦C. The mix-
ture was warmed to −40 ◦C and then re-cooled to −80 ◦C. After
the addition of [G-0]4-exo-Cl (0.23 g = 0.40 mmol) the reaction
mixture was warmed to room temperature and then stirred for
another 24 h. After removal of the volatiles in vacuo, the residue
was washed with 3 × 10 ml of water and then extracted with
n-hexane until the extracts were colourless. The pure reaction
product was obtained as a yellow amorphous solid.
2 H, H(a)), 6.92 (m, 2 H, H(11)), 7.15 (dd,3JHH = 8.2 Hz, 4JHH
=
2.1 Hz, 1 H, H(5)), 7.25 (s, br, 2 H, H(9)), 7.51 (s, br, 1 H, H(3)),
7.94 (d, 3JHH = 8.2 Hz, 1 H, H(6)), 8.43 (m, 2 H, 1H(2)), 10.88
1
13
(s, br, 1 H, NH). { H} C-NMR (75.5 MHz, CDCl3, 298 K): d =
−1.7 (C-k), 17.4/18.6 (C-e, C-g, C-h, C-j), 21.0 (10-CH3), 21.7
(C-b, C-f, C-i), 66.6 (C-a), 84.7 (C-c), 103.0 (C-d), 106.5 (C-3),
119.5 (C-5), 121.3 (C-9), 123.6 (C-6/C-11), 128.4 (C-1), 138.0
(C-2), 147.5 (C-12), 149.1 (C-10), 153.5 (C-7), 160.6 (C-8), 162.3
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(C-4). { H} Si-NMR (79.5 MHz, CDCl3, 298 K): d = −15.1
(≡C–Si–), 0.6 ((CH3)3Si- and Si(CH2)4–). IR (neat): m [cm−1] =
2953 (s), 2911 (s), 2181 (vw), 1632 (m), 1592 (s), 1545 (w), 1467
(w), 1412 (m), 1330 (m), 1247 (s), 1141 (m), 1022 (m), 944 (w),
910 (m), 862 (s), 833 (s), 694 (m). MS (FAB): m/z = 1670.1 [M]+.
C87H173N5OSi13 (1670.48 g.mol−1): calcd.: C 62.55, H 10.43, N
4.19; found: C 62.64, H 10.71, N 3.86.
Yield: 0.67 g (0.33 mmol, 83%). Mp: 46 ◦C. 1H-NMR
(400.16 MHz, CDCl3, 298 K): d = 0.14 (s, 24 H, H(e)), 0.68
(m, 16 H, H(f), H(h)), 1.42 (m, 8 H, H(g)), 2.34 (s, 24 H, 10-
CH3), 2.74 (t, 3JHH = 7.1 Hz, 8 H, H(b)), 4.25 (t, 3JHH = 7.1 Hz,
8 H, H(a)), 6.86 (m, 8 H, H(11)), 7.07 (m, 4 H, H(5)), 7.21 (s, br,
8 H, H(9)), 7.52 (d, 4JHH = 2.1 Hz, 4 H, H(3)), 7.89 (d, 3JHH
=
8.4 Hz, 4 H, H(6)), 8.39 (m, 8 H, 1H(2)), 13.79 (s, br, 4 H,
1
13
NH). { H} C-NMR (100.6 MHz, CDCl3, 298 K): d = −1.5
(C-e), 17.1/18.5 (C-f, C-h), 20.9 (C-g), 21.0 (10-CH3), 21.1 (C-
b), 66.7 (C-a), 86.2 (C-c), 102.5 (C-d), 106.7 (C-3), 119.6 (C-5),
121.0/121.3 (C-9), 123.3/123.6 (C-11), 123.9 (C-6), 128.3 (C-1),
137.9 (C-2), 147.3/147.4 (C-12), 149.1 (C-10), 153.5 (C-7), 160.3
1
29
(C-8), 161.8 (C-4). { H} Si-NMR (79.5 MHz, CDCl3, 298 K):
d = −17.6 (≡C–Si), 1.0 (Si(CH2)–). IR (KBr): m [cm−1] = 2917
(m), 2169 (w), 1633 (s), 1591 (s), 1544 (m), 1466 (m), 1359 (w),
1328 (w), 1242 (m), 1121 (w), 1039 (w), 821 (m). MS (FAB):
D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5
1 4 1 1

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3
m/z = 2006.6 [M]−. C116H128N20O4Si5 (2006.85 g.mol−1): calcd.:
7.1 Hz, 16 H, H(b)), 4.25 (t, JHH = 7.1 Hz, 16 H, H(a)),
C 69.43, H 6.43, N 13.96; found: C 69.19, H 6.70, N 14.06.
6.86 (m, 16 H, H(11)), 7.06 (m, 8 H, H(5)), 7.21 (s, br, 16 H,
3
H(9)), 7.44 (s, br, 8 H, H(3)), 7.89 (d, JHH = 8.3 Hz, 8 H,
1
13
H(6)), 8.39 (m, 16 H, 1H(2)), 13.76 (s, br, 8 H, NH). { H} C-
NMR (75.5 MHz, CDCl3, 298 K): d = −4.9 (C-i), −1.5 (C-e),
17.6–20.8 (C-b, C-f, C-g, C-h, C-j, C-k, C-l), 20.9 (10-CH3),
66.5 (C-a), 86.1 (C-c), 102.4 (C-d), 106.4 (C-3), 119.5 (C-5),
121.0/121.2 (C-9), 123.4/123.6 (C-11), 123.8 (C-6), 128.2 (C-1),
137.8 (C-2), 147.3/147.4 (C-12), 149.0 (C-10), 153.4/153.5 (C-
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29
7), 160.2/160.4 (C-8), 161.6 (C-4). { H} Si-NMR (79.5 MHz,
CDCl3, 298 K): d = −17.7 (≡C–Si), 0.3 (Si(CH2)–), 1.1
(–Si(CH3)–). IR (KBr): m [cm−1] = 2959 (w), 2912 (m), 2875
(w), 2177 (w), 1632 (s), 1590 (s), 1544 (m), 1487 (m), 1466 (m),
1401 (vw), 1359 (w), 1328 (w), 1280 (m), 1242 (m), 1162 (m),
1040 (m), 910 (w), 820 (m), 716 (vw). MS (FAB): m/z = 4326.7
[M]−, 2660.8 [M]2−. C248H292N40O8Si13 (4326.42 g.mol−1): calcd.:
C 68.84, H 6.80, N 12.95; found: C 69.19, H 6.83, N 13.06.
Preparation of [G-0]4-exo-4-[C≡CCH2CH2O]-10-tBuBPI (7b)
A solution of LDA in thf (2 M) (0.67 ml = 1.34 mmol) was slowly
added to a solution of 4-(3-butynoxy)-10-tBuBPI (2b) (0.32 g =
0.67 mmol) in thf (50 ml), which was cooled to −80 ◦C. The mix-
ture was warmed to −40 ◦C and then re-cooled to −80 ◦C. After
the addition of [G-0]4-exo-Cl (87.0 mg = 0.15 mmol) the reaction
mixture was warmed to room temperature and then stirred for
another 24 h. After removal of the volatiles in vacuo, the residue
was washed with 3 × 10 ml of water and then extracted with
n-hexane until the extracts were colourless. The pure reaction
product was obtained as a yellow amorphous solid.
Yield: 0.30 g (0.13 mmol, 86%), Mp: 54 ◦C. 1H-NMR
(300.17 MHz, CDCl3, 298 K): d = 0.15 (s, 24 H, H(e)), 0.69
(m, 16 H, H(f), H(h)), 1.42 (m, 8 H, H(g), 10-C(CH3)3), 2.78 (t,
3JHH = 7.3 Hz, 8 H, H(b)), 4.23 (t, 3JHH = 7.3 Hz, 8 H, H(a)), 7.11
(m, 12 H, H(5), H(11)), 7.41 (m, 8 H, H(9)), 7.54 (m, 4 H, H(3)),
7.92 (d, 3JHH = 8.1 Hz, 4 H, H(6)), 8.46 (m, 8 H, 1H(2)), 13.83
Preparation of [G-1]12-exo-4-[C≡CCH2CH2O]-10-MeBPI (9)
1
13
(s, br, 4 H, NH). { H} C-NMR (75.5 MHz, CDCl3, 298 K):
d = −1.5 (C-e), 17.1/18.5 (C-f, C-h), 20.9 (C-g), 21.1 (C-b), 30.6
(10-C(CH3)3), 34.8 (10-C(CH3)3), 66.7 (C-a), 86.2 (C-c), 102.4
(C-d), 106.6 (C-3), 117.4/117.6 (C-9), 119.7 (C-5), 119.8/119.9
(C-11), 123.8 (C-6), 128.4 (C-1), 138.0 (C-2), 147.5/147.6 (C-
12), 153.5 (C-7), 160.6/160.7 (C-8), 161.8 (C-4), 162.2 (C-10).
A solution of LDA in thf (2 M) (1.85 ml = 3.70 mmol) was
slowly added to a solution of 4-(3-butynoxy)-10-MeBPI (2a)
(0.70 g = 1.85 mmol) in thf (60 ml), which was cooled to
−80 ◦C. The mixture was warmed to −40 ◦C and then re-cooled
to −80 ◦C. After addition of [G-1]12-exo-Cl (0.27 g = 0.14 mmol)
the reaction mixture was warmed to room temperature and
then stirred for another 24 h. After removal of the volatiles in
vacuo, the residue was washed with 3 × 10 ml of water and then
extracted with n-hexane until the extract remains colourless. The
pure reaction product was obtained as a yellow amorphous solid.
Yield: 0.69 g (0.11 mmol, 79%). Mp: 47 ◦C. 1H-NMR
(300.17 MHz, CDCl3, 298 K): d = 0.18 (s, br, 72 H, H(e)), 0.73
(m, br, 64 H, H(f), H(h), H(i), H(k)), 1.42 (m, 32 H, H(g), H(j)),
2.27 (s, br, 72 H, 10-CH3), 2.74 (m, br, 24 H, H(b)), 4.08 (m,
br, 24 H, H(a)), 6.78 (m, 24 H, H(11)), 6.98–7.11 (m, br, 36 H,
H(5), H(9)), 7.33 (s, br, 12 H, H(3)), 7.72 (s, br, 12 H, H(6)), 8.28
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{ H} Si-NMR (79.5 MHz, CDCl3, 298 K): d = −17.7 (≡C–Si),
0.9 (Si(CH2)–). IR (KBr): m [cm−1] = 2957 (m), 2912 (m), 2888
(m), 2172 (w), 1633 (s), 1588 (s), 1533 (s), 1478 (s), 1401 (m),
1367 (m), 1223 (m), 1285 (m), 1263 (m), 1224 (m), 1102 (w), 1042
(m), 1019 (w), 892 (w), 832 (m), 782 (w), 716 (w). MS (FAB):
m/z = 2344.4 [M]+. C140H176N20O4Si5 (2343.50 g.mol−1): calcd.:
C 71.75, H 7.57, N 11.95; found: C 71.93, H 7.71, N 12.04.
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(m, br, 24 H, 1H(2)), 13.67 (s, br, 12 H, NH). { H} C-NMR
(75.5 MHz, CDCl3, 298 K): d = −1.3 (C-e), 17.1–18.6 (C-f, C-g,
C-h, C-i, C-j, C-k), 20.9 (10-CH3), 21.2 (C-b), 66.5 (C-a), 86.1
(C-c), 102.5 (C-d), 106.4 (C-3), 119.2 (C-5), 121.0 (C-9), 123.4
(C-11), 123.6 (C-6), 128.3 (C-1), 137.8 (C-2), 147.2 (C-12), 148.7
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(C-10), 153.4 (C-7), 160.2 (C-8), 161.5 (C-4). { H} Si-NMR
(79.5 MHz, CDCl3, 298 K): d = −17.9 (≡C–Si), 0.7 (Si(CH2)–).
IR (KBr): m [cm−1] = 3420 (m, br), 2952 (w), 2914 (m), 2872 (w),
2177 (m), 1632 (s), 1590 (s), 1544 (m), 1488 (m), 1466 (m), 1400
(vw), 1359 (w), 1328 (w), 1280 (m), 1242 (m), 1162 (w), 1039
(m), 909 (w), 821 (m), 716 (vw), 457 (w). MS (MALDI-TOF):
m/z = 6244.7 [M]−. C360H408N60O12Si17 (6245.05 g.mol−1): calcd.:
C 69.24, H 6.59, N 13.46; found: C 68.90, H 6.83, N 13.04.
Preparation of [G-1]8-exo-4-[C≡CCH2CH2O]-10-MeBPI (8)
A solution of LDA in thf (2 M) (1.40 ml = 2.80 mmol) was slowly
added to a solution of 4-(3-butynoxy)-10-MeBPI (2a) (0.56 g =
1.40 mmol) in thf (60 ml), which was cooled to −80 ◦C. The mix-
ture was warmed to −40 ◦C and then re-cooled to −80 ◦C. After
the addition of [G-1]8-exo-Cl (0.23 g = 0.16 mmol). The reaction
mixture was warmed to room temperature and then stirred for
another 24 h. After removal of the volatiles in vacuo, the residue
was washed with 3 × 10 ml of water and then extracted with
n-hexane until the extracts were colourless. The pure reaction
product was obtained as a yellow amorphous solid.
Yield: 0.57 g (0.13 mmol, 82%), Mp: 42 ◦C. 1H-NMR
(300.17 MHz, CDCl3, 298 K): d = −0.03 (s, 12 H, H(i)), 0.14
(s, 48 H, H(e)), 0.68 (m, 48 H, H(f), H(h), H(j), H(l)), 1.42 (m,
3
24 H, H(g), H(k)), 2.33 (s, br, 48 H, 10-CH3), 2.74 (t, JHH
=
1 4 1 2
D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5

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Preparation of [G-2]16-exo-4-[C≡CCH2CH2O]-10-MeBPI (10)
106.8 (C-3), 119.0 (C-5), 121.2 (C-9), 123.6 (C-6), 126.4 (C-11),
130.4 (C-1), 139.9 (C-2), 151.1 (C-10), 151.5 (C-7/C-8), 152.7 (C-
A solution of LDA in thf (2 M) (0.76 ml = 1.52 mmol) was
slowly added to a solution of 4-(3-butynoxy)-10-MeBPI (2a)
(0.30 g = 0.76 mmol) in thf (30 ml), which was cooled to
−80 ◦C. The mixture was warmed to −40 ◦C and then re-cooled
to −80 ◦C. After the addition of [G-2]16-exo-Cl (0.14 g = 43.3
lmol) the reaction mixture was warmed to room temperature
and then stirred for another 24 h. After removal of the volatiles
in vacuo, the residue was washed with 3 × 10 ml of water and
then extracted with n-hexane until the extracts were colourless.
The pure reaction product was obtained as a yellow amorphous
solid.
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12), 153.6 (C-7/C-8), 161.7 (C-4). { H} Si-NMR (79.5 MHz,
CDCl3, 298 K): d = −8.7 (≡C–Si). IR (KBr): m [cm−1] = 2954 (w),
2922 (w), 2857 (w), 2164 (vw), 1582 (s), 1519 (m), 1470 (s), 1405
(vw), 1364 (m), 1329 (vw), 1296 (w), 1232 (w), 1188 (w), 1106
(w), 1088 (vw), 1020 (w), 933 (vw), 885 (vw), 825 (m), 808 (m),
776 (w), 679 (vw). C30H34ClN5OPdSi (650.58 g.mol−1): calcd.: C
55.39, H 5.27, N 10.76; found: C 54.93, H 4.91, N 10.45.
Yield: 0.29 g (32.9 lmol, 76%). Mp: 54 ◦C. 1H-NMR
(300.17 MHz, CDCl3, 298 K): d = −0.05 (s, 12 H, H(m)), −0.04
(s, 24 H, H(i)), 0.15 (s, 96 H, H(e)), 0.68 (m, 112 H, H(f), H(h),
H(j), H(l), H(n), H(p)), 1.42 (m, 56 H, H(g), H(k), H(o)), 2.33
(s, br, 96 H, 10-CH3), 2.74 (m, br, 32 H, H(b)), 4.17 (m, br, 32 H,
H(a)), 6.86 (m, br, 32 H, H(11)), 7.07 (m, br, 16 H, H(5)), 7.20 (s,
br, 32 H, H(9)), 7.44 (s, br, 16 H, H(3)), 7.85 (m, br, 16 H, H(6)),
1
13
8.38 (m, br, 32 H, 1H(2)), 13.79 (s, br, 16 H, NH). { H} C-
NMR (75.5 MHz, CDCl3, 298 K): d = −4.9 (C-i, C-m), −1.5
(C-e), 18.3–19.9 (C-f, C-g, C-h, C-j, C-k, C-l, C-n, C-o, C-p),
20.8 (C-b), 20.9 (10-CH3), 66.5 (C-a), 86.1 (C-c), 102.4 (C-d),
106.4 (C-3), 119.4 (C-5), 120.9/121.1 (C-9), 123.4/123.5 (C-11),
123.6 (C-6), 128.4 (C-1), 137.9 (C-2), 147.3 (C-12), 148.9 (C-
10), 153.4 (C-7), 160.3/160.5 (C-8), 161.7 (C-4). { H} Si-NMR
(79.5 MHz, CDCl3, 298 K): d = −17.7 (≡C–Si), 0.8/0.9/1.1
(Si(CH2)4–, Si(CH3)–). IR (KBr): m [cm−1] = 3428 (m, br), 2912
(m), 2875 (w), 2177 (m), 1633 (s), 1590 (s), 1543 (m), 1487 (m),
1465 (m), 1401 (vw), 1358 (w), 1328 (w), 1280 (w), 1242 (m), 1162
(m), 1039 (m), 910 (w), 818 (m), 716 (vw). MS (MALDI-TOF):
m/z = 8963.2 [M]−. C512H620N80O16Si29 (8965.56 g.mol−1): calcd.:
C 68.59, H 6.97, N 12.49; found: C 68.60, H 7.16, N 12.37.
[G-2]1-endo-4-[C≡CCH2CH2O]-10-MeBPIPdCl (12)
Yield: 55.0 mg (30.1 lmol, 56%). 1H-NMR (300.17 MHz,
CD2Cl2, 298 K): d = −0.02 (s, 81 H, H(k)), 0.57 (m, br, 48 H,
H(e), H(g), H(h), H(j)), 1.35 (m, 24 H, H(f), H(i)), 2.42 (s, br,
6 H, 10-CH3), 2.79 (t, 3JHH = 7.3 Hz, 2 H, H(b)), 4.24 (t, 3JHH
=
1
29
7.3 Hz, 2 H, H(a)), 6.90 (m, 2 H, H(11)), 7.15 (d, br,3JHH
=
8.1 Hz, 1 H, H(5)), 7.36 (m, br, 2 H, H(9)), 7.50 (s, br, 1 H,
H(3)), 7.87 (d, 3JHH = 8.1 Hz, 1 H, H(6)), 9.63 (m, 2 H, 1H(2)).
1
13
{ H} C-NMR (100.6 MHz, CD2Cl2, 298 K): d = −1.4 (C-k),
17.8–19.0 (C-e, C-g, C-h, C-j), 20.7 (10-CH3), 22.1 (C-b, C-f, C-
i), 67.0 (C-a), 84.9 (C-c), 100.4 (C-d), 107.2 (C-3), 118.7 (C-5),
121.2 (C-9), 123.6 (C-6), 125.4 (C-11), 135.8 (C-1), 140.2 (C-2),
151.5 (C-10), 151.8 (C-7/C-8), 152.7 (C-12), 153.6 (C-7/C-8),
1
29
161.9 (C-4). { H} Si-NMR (79.5 MHz, CDCl3, 298 K): d =
−21.9 (≡C–Si), 0.3 ((CH3)3Si–). IR (neat): m [cm−1] = 2953 (s),
2921 (s), 2854 (s), 2180 (vw), 1584 (m), 1469 (m), 1408 (m), 1336
(w), 1259 (s), 1246 (s), 1138 (m), 1096 (s), 1021 (s), 910 (m), 861
(s), 834 (s), 799 (s), 693 (m). MS (FAB): m/z = 1774.9 [M −
Cl]+. C87H172ClN5OPdSi13 (1811.34 g.mol−1): calcd.: C 57.69, H
9.57, N 3.87; found: C 57.99, H 9.97, N 3.42.
General procedure for the preparation of the palladium
complexes 11–14
The BPI-substituted carbosilane (0.05 mmol) was dissolved in
5 ml of CH2Cl2 and 1.5 molar equivalents of triethylamine
per BPI-ligand were added to this solution. Subsequently, 1.5
molar equivalents of [(PhCN)2PdCl2] were added for every
BPI-equivalent and the reaction mixture then stirred at room
temperature for 24 h. After removal of the volatiles in vacuo
the yellow–ochre residue was washed with 3 × 10 ml of water
and 3 × 10 ml of n-hexane. The crude product was taken up
in CH2Cl2, filtered through Celite and the filtrate dried over
MgSO4. After removal of the solvent in vacuo, the product
palladium complex was obtained as an analytically pure yellow
oil (11) or amorphous solid (12–14).
[G-0]4-exo-4-[C≡CCH2CH2O]-10-MeBPIPdCl (13a)
Yield: 14.5 mg (5.65 lmol, 63%), Mp: 88 ◦C. 1H-NMR
(300.17 MHz, CDCl3, 298 K): d = 0.19 (s, 24 H, H(e)), 0.73
(m, 16 H, H(f), H(h)), 1.51 (m, 8 H, H(g)), 2.35 (s, br, 24 H,
3
3
10-CH3), 2.78 (t, JHH = 7.4 Hz, 8 H, H(b)), 4.09 (t, JHH
=
7.4 Hz, 8 H, H(a)), 6.75 (m, 8 H, H(11)), 6.86 (m, 4 H, H(5)),
3
7.15–7.19 (m, br, 12 H, H(3), H(9)), 7.67 (d, JHH = 8.1 Hz,
1
13
4 H, H(6)), 9.50 (m, 8 H, 1H(2)). { H} C-NMR (100.6 MHz,
CDCl3, 298 K): d = −1.4 (C-e), 17.1/18.7/20.8 (C-f, C-g, C-h),
20.9 (10-CH3), 21.0 (C-b), 66.7 (C-a), 86.3 (C-c), 102.6 (C-d),
107.2 (C-3), 118.8 (C-5), 121.4/121.5 (C-9), 124.4 (C-6), 125.6
(C-11), 126.4 (C-1), 139.0 (C-2), 150.3 (C-10), 151.3/151.4 (C-
4-[tBuSi(CH3)2C≡CCH2CH2O]-10-MeBPIPdCl (11)
Yield: 10.0 mg (19.2 lmol, 65%). Mp: 140 ◦C. 1H-NMR
(300.17 MHz, CDCl3, 298 K): d = 0.11 (s, 6 H, H(e)), 0.95
3
(s, 9 H, H(g)), 2.40 (s, 6 H, 10-CH3), 2.79 (t, JHH = 7.3 Hz,
3
1
29
2 H, H(b)), 4.23 (t, JHH = 7.3 Hz, 2 H, H(a)), 6.85 (m, 2 H,
7/C-8), 152.9 (C-12), 154.1 (C-7/C-8), 161.7 (C-4). { H} Si-
NMR (79.5 MHz, CDCl3, 298 K): d = −17.4 (≡C-Si), 1.2
(–Si(CH3)2–). IR (neat): m [cm−1] = 2950 (w), 2906 (w), 2883
(w), 2174 (w), 1581 (s), 1519 (m), 1470 (s), 1403 (vw), 1364 (w),
1331 (w), 1288 (m), 1231 (m), 1189 (w), 1102 (w), 1085 (w),
1020 (w), 815 (m). MS (FAB): m/z = 2534.5 [M − Cl]+, 1249.4
3
4
H(11)), 6.97 (dd, JHH = 8.1 Hz, JHH = 2.5 Hz, 1 H, H(5)),
7.26 (m, 2 H, H(9)), 7.45 (d, 4JHH = 2.5 Hz, 1 H, H(3)), 7.82 (d,
1
13
3JHH = 8.1 Hz, 1 H, H(6)), 9.64 (m, 2 H, 1H(2)). { H} C-NMR
(75.5 MHz, CDCl3, 298 K): d = −4.52 (C-e), 16.3 (C-f), 20.6 (10-
CH3), 20.9 (C-b), 26.1 (C-g), 66.7 (C-a), 92.7 (C-c), 105.7 (C-d),
D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5
1 4 1 3

View Article Online
[M − 2·Cl]2+. C116H124Cl4N20O4Pd4Si5 (2570.31 g.mol−1): calcd.:
C 54.21, H 4.86, N 10.90; found: C 53.89, H 4.67, N 10.55.
Acknowledgements
We thank the Deutsche Forschungsgemeinschaft for funding
and Wacker Chemie AG for generous gifts of basic chemicals.
[G-0]4-exo-4-[C≡CCH2CH2O]-10-tBuBPIPdCl (13b)
Yield: 20.0 mg (6.96 lmol, 65%), Mp: 100 ◦C (dec.). 1H-NMR
(300.17 MHz, CDCl3, 298 K): d = 0.17 (s, 24 H, H(e)), 0.72 (m,
References
16 H, H(f), H(h)), 1.51 (m, 80 H, H(g), 10-tBu), 2.81 (t, 3JHH
=
7.4 Hz, 8 H, H(b)), 4.21 (t, 3JHH = 7.4 Hz, 8 H, H(a)), 6.99 (m,
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12 H, H(5), H(11)), 7.32–7.44 (m, br, 12 H, H(3), H(9)), 7.70 (d,
1
13
3JHH = 8.1 Hz, 4 H, H(6)), 9.59 (m, 8 H, 1H(2)). { H} C-NMR
(100.6 MHz, CDCl3, 298 K): d = −1.4 (C-e), 17.1/18.6/20.9
(C-b, C-f, C-g, C-h), 30.2 (10-C(CH3)3), 34.9 (10-C(CH3)3), 66.6
(C-a), 86.2 (C-c), 102.5 (C-d), 106.7 (C-3), 117.7 (C-9), 118.6
(C-5), 122.9 (C-11), 123.4 (C-6), 128.3 (C-1), 139.9 (C-2), 151.7
(C-7/C-8), 152.7 (C-12), 153.2 (C-7/C-8), 161.5 (C-4), 163.5
1
29
(C-10). { H} Si-NMR (79.5 MHz, CDCl3, 298 K): d = −17.5
(≡C–Si), 1.1 (–Si(CH3)2–). IR (neat): m [cm−1] = 2996 (m), 2820
(w), 2867 (w), 2166 (vw), 1605 (m), 1573 (s), 1509 (m), 1479 (s),
1398 (m), 1366 (m), 1329 (w), 1297 (w), 1281 (w), 1249 (w), 1222
(m), 1207 (m), 1185 (m), 1143 (w), 1106 (m), 1079 (m), 1016 (w),
946 (vw), 920 (w), 888 (w), 824 (m), 716 (vw). MS (FAB): m/z =
2869.7 [M − Cl]+, 2834.2 [M − 2·Cl]+. C140H172Cl4N20O4Pd4Si5
(2906.96 g.mol−1): calcd.: C 57.85, H 5.96, N 9.64; found: C
57.69, H 5.55, N 10.03.
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[G-1]8-exo-4-[C≡CCH2CH2O]-10-MeBPIPdCl (14)
Yield: 7.00 mg (1.26 lmol, 25%). Mp: 103 ◦C. 1H-NMR
(300.17 MHz, CDCl3, 298 K): d = 0.03 (s, 12 H, H(i)), 0.19
(s, 48 H, H(e)), 0.77 (m, 48 H, H(f), H(h), H(j), H(l)), 1.43 (m,
3
24 H, H(g), H(k)), 2.33 (s, br, 48 H, 10-CH3), 2.75 (t, JHH
=
3
6.8 Hz, 16 H, H(b)), 4.25 (t, JHH = 6.8 Hz, 16 H, H(a)), 6.72
(m, 16 H, H(11)), 6.83 (m, br, 8 H, H(5)), 7.09 (s, br, 16 H,
H(9)), 7.17 (s, br, 8 H, H(3)), 7.59 (m, br, 8 H, H(6)), 9.48 (m,
1
13
br, 16 H, 1H(2)). { H} C-NMR (75.5 MHz, CDCl3, 298 K):
d = −4.8 (C-i), −1.4 (C-e), 17.1/18.4/18.6/19.2 (C-f, C-g, C-h,
C-j, C-k, C-l), 20.5 (C-b), 20.8 (10-CH3), 66.3 (C-a), 86.1 (C-c),
102.5 (C-d), 106.1 (C-3), 118.2 (C-5), 120.7 (C-9), 123.1 (C-6),
126.4 (C-11), 130.1 (C-1), 139.5 (C-2), 150.4 (C-10), 151.2 (C-
1
29
7/C-8), 152.5 (C-12), 152.7 (C-7/C-8), 160.9 (C-4). { H} Si-
NMR (79.5 MHz, CDCl3, 298 K): d = −17.6 (≡C–Si), 0.5
(Si(CH2)4–), 1.2 (–Si(CH3)–). IR (neat): m [cm−1] = 2963 (w),
2906 (m), 2852 (w), 2173 (w), 1579 (s), 1517 (m), 1468 (m),
1397 (vw), 1364 (w), 1261 (s), 1228 (w), 1188 (m), 1103 (s),
1019 (s), 803 (s). MS (MALDI-TOF): m/z = 5416.9 [M − Cl]+.
C248H284Cl8N40O8Pd8Si13 (5453.34 g.mol−1): calcd.: C 54.62, H
5.25, N 10.27; found: C 54.42, H 5.47, N 10.48.
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D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5

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D a l t o n T r a n s . , 2 0 0 5 , 1 4 0 3 – 1 4 1 5
1 4 1 5