Synthesis of palladium(II) complexes of bidentate phosphano ligands with carbosilane substituents

Article abstract of DOI:10.1016/j.jorganchem.2012.07.032

The synthesis of carbosilane dendrons with bidentate bis(diphenylphosphanomethyl)amino ligands at the focal point and terminal alkyl or dimethylamino end-groups, together with their palladium(II) complexes and a cationic ammonium-quaternized derivative, is described. All compounds were characterized by elemental analysis and NMR spectroscopy (¹H, ¹³C, ³¹P and ²⁹Si).

Full text of DOI:10.1016/j.jorganchem.2012.07.032

Journal of Organometallic Chemistry 717 (2012) 88e98
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis of palladium(II) complexes of bidentate phosphano ligands
with carbosilane substituents
*
*
Susana Vigo, Román Andrés , Pilar Gómez-Sal, Javier de la Mata, Ernesto de Jesús
Departamento de Química Inorgánica, Universidad de Alcalá, Campus Universitario, 28871 Alcalá de Henares, Madrid, Spain
a r t i c l e i n f o
a b s t r a c t
Article history:
The synthesis of carbosilane dendrons with bidentate bis(diphenylphosphanomethyl)amino ligands at
the focal point and terminal alkyl or dimethylamino end-groups, together with their palladium(II)
complexes and a cationic ammonium-quaternized derivative, is described. All compounds were char-
acterized by elemental analysis and NMR spectroscopy (1H, 13C, 31P and 29Si).
Received 11 April 2012
Received in revised form
6 July 2012
Accepted 18 July 2012
Ó 2012 Elsevier B.V. All rights reserved.
Keywords:
Palladium
Phosphane ligand
Amphiphilic ligand
Dendrimer
HeckeMizoroki reaction
1. Introduction
materials in catalysis because of their inertness and the stability
imparted by the strong and relatively unpolarized SieC bonds [7,8].
The development of organic reactions catalyzed by metal
complexes in the aqueous phase [1] has encouraged the synthesis
of water-soluble versions of the traditional hydrophobic ligands
used in organometallic catalysis in the last two decades [2]. Thus,
a large variety of aryl- and alkyl-substituted tertiary phosphanes
have been rendered water soluble by means of ionic (sulfonate,
carboxylate, phosphonate, ammonium.) or nonionic hydrophilic
substituents (polyols, carbohydrates, polyethers.) [2,3]. Indeed,
amphiphilic phosphanes add phase-transfer abilities to the water-
soluble ligand, often resulting in improved catalytic activities and
selectivities in biphasic processes [3].
Dendrimers and dendrons are versatile molecules for the
construction of catalysts adapted to a particular medium [4]. Thus,
functional groups can be methodically introduced into the desired
positions of a single dendritic molecule during or after the stepwise
construction, and voids and channels in the interior of the branched
structure can host molecules in an environment of adjustable
polarity, whereas interaction of the end-groups with the solvent
modulates the solubility of the macromolecule as a whole [5].
Of the many dendritic structures developed over the last few
decades, carbosilane dendrimers [6] have rapidly moved to the
forefront as regards the application of these hyperbranched
Krska and Seyferth reported the first examples of amphiphilic
carbosilane dendrimers in 1998 and demonstrated their ability to
enhance the solubility of lipophilic alkyl-substituted benzene
derivatives [9]. We have become interested in the synthesis of
metal-functionalized carbosilane-based dendritic catalysts over the
last few years [10]. Indeed, and closely related with the topic of this
report, we showed the effect of the bonding of triarylphosphane
ligands to carbosilane dendrons on the solubilization of palladium
catalysts in supercritical CO2 [11]. Likewise, in a different study, we
prepared mono- and bi-dentate phosphanes with ammonium-
functionalized (non-dendritic) carbosilane substituents [12],
although the metal complexes of these phosphanes were found to
be poorly soluble in water. Incorporation of the ligand at the focal
point, and the ammonium groups at the periphery, of a carbosilane
dendron multiplies the number of solubilizing groups and there-
fore should increase the water solubility of the whole molecule.
The synthesis of carbosilane structures with reactive functions
at both the focal point and periphery is challenging [13] as most
such functions are incompatible with the sequence of reactions
employed in the divergent growth of a carbosilane and have to be
introduced at the focal point after construction of the dendritic
structure. The usual strategies employed to solve this problem
make use of an inert protector of the focal point during carbosilane
synthesis that can be modified or replaced to introduce the desired
functionality as the last synthetic step [14]. For instance, we have
shown that a phenyl group linked to the core silicon atom of
* Corresponding authors. Tel.: þ34 91 885 4603; fax: þ34 91 885 4683.
E-mail addresses: roman.andres@uah.es (R. Andrés), ernesto.dejesus@uah.es
(E. de Jesús).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.07.032

S. Vigo et al. / Journal of Organometallic Chemistry 717 (2012) 88e98
89
a carbosilane can be replaced by nucleophiles upon acid-induced
cleavage of the siliconephenyl bond [15,16]. This route has led to
the synthesis of carbosilane dendrons doubly functionalized with
SieCl bonds at the focal point and group 4 metallocene complexes
at the periphery [17].
Herein we extend these studies to the preparation of carbosilane
dendrons bearing bidentate bis(diphenylphosphanomethyl)amino
ligands at the focal point and alkyl or ammonium groups at the
afforded PP:SiMe3, which contains a direct SieAr bond. Both
PP:OSiMe3 and PP:SiMe3 were obtained in good yields (z75%) as
colorless, analytically pure oils. Siliconearyloxide bonds are,
however, moisture-sensitive [19], thus meaning that the palladium
dichloride complex of phosphane PP:OSiMe3 (see below)
undergoes partial protolysis when exposed to air. Subsequent
studies therefore used direct siliconecarbon bonds only.
The last step of this exploratory work involved functionalization
of the ligand with a hydrophilic functionality. Chloro(chloromethyl)
dimethylsilane is an interesting synthetic building block for this
due to the quite different reactivity of the siliconechloride and
carbonechloride bonds. As illustrated in Scheme 1, the lithium
derivative PP:Li reacts selectively with the more electrophilic
siliconechloride bond at low temperature to afford the interme-
diate C6H4{1-N(CH2PPh2)2}(4-SiMe2CH2Cl), which was character-
ized by NMR spectroscopy and subsequently used without prior
purification. The carbonechloride bond of this intermediate reacts
with 2-dimethylaminoethanethiol, added as hydrochloride, at
80 ꢀC in methanol/water in the presence of a base to afford the
amphiphilic diphosphane PP:NMe2 as a yellow, analytically pure oil
in 69% yield. The methanol/water mixture has to be perfectly
deoxygenated before use to avoid oxidation of the phosphane. This
reaction was previously reported by Krska and Seyferth for the
synthesis of water-soluble carbosilane dendrimers and forms sulfur
linkages that are stable in water [9].
Palladium dichloride chelate complexes [PdCl2(PP:X)] were
obtained as yellow-orange solids in high yields (74e87%) by
displacement of 1,5-cyclooctadiene (cod) from [PdCl2(cod)] by the
PP:X ligand. Formation of the complexes shifts the 31P resonance
downfield from ꢁ27 ꢂ 1 ppm in the ligands to z10 ppm in the
complexes, both of which are typical values for bis(diphenylphos-
phanomethyl)amines and their Pd complexes, respectively
[18,20,21]. Another significant change in the NMR parameters
concerns the increase in the 1J(CeP) coupling constant of the
periphery.
para-Functionalized
N,N-bis(diphenylphosphano-
methyl)anilines of formula (4-XeC6H4)N(CH2PPh2)2 (X ¼ OH, Br)
are accessible by simple synthetic procedures and can be grafted
onto carbosilane dendrons via the hydroxyl or bromo functional-
ities (Scheme 1). Their palladium(II) complexes have also been
prepared and tested in a model Heck cross-coupling reaction.
2. Results and discussion
2.1. Synthesis of non-dendritic phosphanes and their palladium
complexes
We first explored the synthetic steps involved in the bonding of
ligands and hydrophilic groups to a carbosilane structure using
simple silanes as model analogs (Scheme 1). In the first step, the
modified aryl-bis(diphenylphosphanomethyl)amines PP:OH and
PP:Br were prepared in almost quantitative yields (>90%) by
treating the corresponding para-bromo- or para-hydroxy-
substituted aniline with paraformaldehyde and diphenylphos-
phane in hot toluene under a rigorously controlled oxygen-free
atmosphere, as reported elsewhere [18]. The next step involved
silylation of the aniline para position by treatment of chloro-
trimethylsilane with phenol PP:OH in the presence of triethyl-
amine or with the lithiated salt of the bromoaryl phosphane PP:Br.
The phenolysis reaction afforded PP:OSiMe3 in which both moie-
ties are linked through a SieOeAr bond, whereas the lithiation
PPh2
X
NH2
Me3Si
N
PPh2
PP:SiMe3
+ 2 (CH2O)
+ 2 HPPh2
Toluene
C
n
C
ClSiMe3 LiCl
PPh2
PPh2
n
n
X = Br
THF
Li
BuBr
PP:Li
X = OH
THF
X
N
(not isolated)
C
i. NEt3
ii. ClSiMe3
NHEt3Cl
N
ClSiMe2(CH2Cl)
LiCl
C
X = OH (PP:OH), Br (PP:Br)
PPh2
PPh2
PPh2
PPh2
Me3SiO
N
(ClCH2)Me2Si
PP:CH2Cl
PP:OSiMe3
Ph2
P
Cl
Cl
CH3OH / H2O
C
NMe2 HCl
NaOH
HS
[PdCl2(cod)]
CH2Cl2
Pd
X
N
PP:X
P
Ph2
PPh2
PPh2
Me2N
S
N
Si
[PdCl2(PP:R)]
Me2
X = OH, Br, OSiMe3, SiMe3,
SiMe2CH2SCH2CH2NMe2
PP:NMe2
Scheme 1. Synthesis of non-dendritic phosphanes and their palladium complexes.

90
S. Vigo et al. / Journal of Organometallic Chemistry 717 (2012) 88e98
The second part of the preparation is the deprotection step in
which the aryl group at the focal point is removed under acidic
conditions and replaced by a nucleophile (chloride in the case of
dendrons Cl:G1:Xn on Scheme 2). Electron-donating substituents
on the aryl leaving-group activate the SieC bond and soften the
conditions required for bond cleavage. The order of lability of the
aryl groups used in this work is 2,4,6-trimethoxyphenyl > 4-
methoxyphenyl > phenyl. Fewer methoxy substituents means
harsher deprotection conditions but also means that the
siliconearyl bond is less prone to undesired leaching during den-
drimer growth due to the small amounts of HCl generated by
hydrolysis of chlorosilane reagents [17].
Br
Cl(2)
N
Pd
P(2)
C(2)
C(3)
Cl(1)
P(1)
C(1)
The more resistant phenyl or 4-methoxyphenyl groups were
used during preparation of the alkyl-terminated dendrons
Ar:G1:Etn, where a chlorosilane reagent (HSiMe2Cl) is used. When
analogous preparations were tested with the trisubstituted aryl, the
systematic formation of 2,4,6-trimethoxybenzene was observed in
the hydrosilylation step (up to 15% by 1H NMR spectroscopy),
whereas the 4-methoxyphenylesilicon bonds remained unaffected
under the same experimental conditions. Cleavage of the
siliconearyl bonds was performed with triflic acid to afford den-
drons Cl:G1:Etn after addition of lithium chloride. In this case, the
use of ethereal solutions of the more convenient HCl reagent
resulted in only partial conversions under the conditions tested.
The better leaving group (2,4,6-trimethoxyphenyl) was preferred
for the preparation of Cl:G1:(CH2Cl)3. The absence of direct
siliconechloro bonds in the (chloromethyl)dimethylsilane avoids
problems of contamination with HCl and therefore of undesired
cleavage of the siliconearyl bonds. Cleavage is in this case conve-
niently performed with hydrogen chloride, which directly converts
the Si-aryl of Ar:G1:(CH2Cl)3 into a SieCl bond in Cl:G1:(CH2Cl)3
under milder conditions [24].
In the next step of the preparative route, the phosphane func-
tionalities were introduced at thefocalpointofdendronsCl:G1:X3 by
treatmentof their siliconechloride bondswiththelithium derivative
of PP:Br to afford compounds PP:G1:X3 under similar conditions to
those described in Scheme 1 for simple silanes. The chloromethyl-
terminated phosphane PP:G1:(CH2Cl)3 was then transformed into
the ammonium-terminated dendron PP:G1:(NMe2)3 by treatment
with 2-(dimethylamino)ethanethiol in the presence of a base in
methanol/water. These phosphanes were obtained in good yields as
colorless oils that readily oxidize in the presence of traces of air.
The extension of this preparative approach to the synthesis of
larger dendrons is theoretically feasible, as we have demonstrated
previously [15,17]. Thus, the initial alkenylation shown in Scheme 2
has to be followed by successive hydrosilylations with trichloro- or
di-chloromethylsilane and alkenylations with allylmagnesium
bromide to reach the desired generation before introducing the
SiMe2Cl or SiMe2(CH2Cl) end-groups. Preparation of the second-
generation analogs of the alkyl-terminated dendrons was first
attempted with a triply-branched structure. However, the synthesis
of PP:G2:(Et)6 failed in the last step when the aryl protector had to
be replaced by the diphosphine ligand at the focal-point of the
molecule. In contrast, the doubly-branched analog PP:G2:(Et)4
(Scheme 2) was successfully obtained by the same procedure, thus
highlighting the importance of steric effects during the focal-point
functionalization of dendrons.
Fig. 1. Molecular structure of complex [PdCl2(PP:Br)] obtained by X-ray diffraction.
Selected bond lengths (Å) and angles (ꢀ): PdeP(1) 2.240(5), PdeP(2) 2.245(5), PdeCl(2)
2.340(5), PdeCl(1) 2.366(5), NeC(2) 1.45(2), NeC(1) 1.563(17), P(1)eC(1) 1.804(16),
P(2)eC(2) 1.857(19), P(1)ePdeP(2) 95.06(16), P(1)ePdeCl(2) 178.3(2), P(1)ePdeCl(1)
87.76(18), P(2)ePdeCl(2) 85.73(17), P(2)ePdeCl(1) 176.4(2), Cl(2)ePdeCl(1) 91.39(17),
C(2)eNeC(1) 105.6(11), C(1)eP(1)ePd 119.2(5), C(2)eP(2)ePd 116.8(6), NeC(1)eP(1)
112.4(10), NeC(2)eP(2) 115.4(12).
methylene resonance from 13 to 16 Hz in the ligands to 40e47 Hz in
the complexes.
The structure of the palladium complex [PdCl2(PP:Br)] has been
confirmed byX-ray diffraction methods (Fig.1). The asymmetric unit
of the unit cell contains three molecules of the complex together
with three molecules of chloroform. These molecules are very
similar, with the exception of a small difference in the orientation of
the 4-bromophenyl groups. The palladium complex displays a cis-
planar PdP2Cl2 coordination environment and a flattened boat
conformation for the six-membered PdP2C2N ring. The structural
parameters of the Pd environment and metallocycle are similar to
those found in the parent complex [PdCl2{(PPh2CH2)2NC6H5}] [22]
and in other related aryl-substituted complexes [23].
2.2. Synthesis of dendritic phosphanes and their complexes
In the second part of this work, the chloro(chloromethyl)
dimethylsilane synthon was replaced by carbosilane dendrons in
order to prepare dendritic hydrophobic alkyl- and amphiphilic
ammonium-terminated diphosphanes (Scheme 2). The synthetic
strategy was based on our previous reports of the post-
functionalization of the focal point of carbosilane dendrons based
on the protolytic cleavage of arylesilicon bonds [15,17].
The process starts with an arylchlorosilane core from which the
carbosilane dendron can be grown up to the desired generation by
successive alkenylation and hydrosilylation reactions and termi-
nated with the required end-groups in the last preparative step
[17]. The three first-generation carbosilane dendrons Ar:G1:Xn in
Scheme
2 were prepared initially. Two of these are alkyl-
terminated dendrons with two (Ar:G1:Et2) or three (Ar:G1:Et3)
branches in which the hydrosilylation step was followed by alkyl-
ation of the peripheral SieCl bonds with EtMgCl. The third
(Ar:G1:(CH2Cl)3) has three peripheral chloromethyl functionalities
that allow the subsequent incorporation of hydrophilic ammonium
groups. Three different aryl groups (phenyl, 4-methoxyphenyl or
2,4,6-trimethoxyphenyl) have been incorporated to the focal point
of the dendrons as explained below.
All carbosilane derivatives were isolated and characterized by C,
H, N, S elemental analysis and 1H, 13C, 29Si, and, if applicable, 31P
NMR spectroscopy, as detailed in the Experimental section. 1H NMR
spectroscopy was particularly useful for monitoring the growth and
deprotection of the carbosilane dendrons. Monitoring of the reac-
tions during the hydrosilylation step is highly recommended
[14j,17]. 29Si NMR chemical shifts were especially useful for iden-
tifying the different silicon environments that appear in the

S. Vigo et al. / Journal of Organometallic Chemistry 717 (2012) 88e98
91
Ar SiMe Cl
n
n
i.
BrMg
Me
H Si CH2Cl
Me
ii. HSiMe2Cl
iii. EtMgCl
ii. HSiMe2Cl
iii. EtMgCl
n = 2
n = 3
n = 3
ii.
SiMe(CH2CH2CH2SiMe2Et)
Si(CH2CH2CH2SiMe2Et)3
Ar Si(CH2CH2CH2SiMe2(CH2Cl))3
2
Ar:G1:Et2
Ar:G1:Et3
Ar:G1:(CH2Cl)3
OMe
MeO
MeO
HCl
Ar =
Ar =
Ar =
OMe
Et2O
i. CF3SO3H
toluene
i. CF3SO3H
toluene
ii. LiCl
ii. LiCl
Cl
Cl Si
Si
Cl Si
Me
SiMe2Et
3
2
Cl Si
SiMe2Et
3
Me2
Cl:G1:(CH2Cl)3
Cl:G1:(Et)2
Cl:G1:(Et)3
C
C
C
PP:Li
PP:Li
PP:Li
Ph2P
Ph2P
Ph2P
Ph2P
Ph2P
Ph2P
Cl
N
Si
Si
Me2
N
Si
SiMe2Et
3
N
Si
SiMe2Et
3
2
Me
PP:G1:(CH2Cl)3
PP:G1:(Et)3
PP:G1:(Et)2
CH3OH / H2O
C
NMe2 HCl
NaOH
HS
Ph2P
Ph2P
N
Si
Si
SiMe2Et
2
2
Me
Me
PP:G2:(Et)4
Ph2P
Ph2P
NMe2
S
N
Si
Si
3
Me2
PP:G1:(NMe2)3
Scheme 2. Synthesis of dendritic phosphanes.
expected positions [25]: the ArSiR3-type of silicon atoms (R ¼ alkyl)
at the focal point of both Ar:G1:X3 and PP:G1:X3 dendrons appear
at ꢁ4.5 ꢂ 1 ppm, the SiR4-type (SiMe2Et and SiMe2(CH2Cl) end
groups) are found at around 3 ppm, whereas the SiR3Cl silicon
atoms (focal-point or terminal) are located at 31 ꢂ 1 ppm. The 31P
nuclei of phosphanes PP:G1:X3 are found in the same range of
chemical shifts as those described above for the parent PP:X
phosphanes (ꢁ27 ꢂ 1 ppm).
found to be fairly insoluble in most common organic solvents,
except dimethyl sulfoxide, and was also found to be insoluble in
water at room temperature.
2.3. Catalytic tests on the Heck reaction
The palladium complexes reported here, together with the
reference derivative [PdCl2{(Ph2PCH2)2NPh}], were tested in
the palladium-catalyzed MizorokieHeck reaction between
4-iodotoluene and methyl acrylate (Table 1). The reaction was
carried out in acetonitrile at 80 ꢀC, with palladium loadings of 1 mol
% and triethylamine as the base. Methyl 4-methylcinnamate was
the only product detected by GC analysis with all the catalysts
tested. These palladium precursors are not very active under these
reaction conditions, affording conversions ranging from 15% to 62%
after 24 h of reaction. They also showed extensive decomposition
by precipitation of black palladium with the exception of
dimethylamino-substituted complex PP:G1:(NMe2)3 which is also
the less active catalyst.
The corresponding [PdCl2(PP:G1:X3)] complexes were prepared
by treatment of [PdCl2(cod)] with the appropriate phosphane in
THF (see Scheme 3). They were isolated as orange solids after
elimination of volatiles and characterized by elemental analysis and
NMR spectroscopy, as detailed in the Experimental section.
The palladium dichloride complex of the dimethylamino-
terminated dendron PP:G1:(NMe)2 was found to be completely
insoluble in water but soluble in organic solvents such as toluene,
THF and CH2Cl2. The terminal dimethylamino groups were qua-
ternized by treatment with an excess of iodomethane, although this
quaternization was accompanied by chlorido/iodido ligand
exchange at the metal centers [12]. This exchange was reflected in
the 31P NMR resonance, which shifted from a typical value of
10 ppm found in the dichloride complexes to ꢁ10.4 ppm, a similar
value to that reported for [PdI2{(Ph2PCH2)2NPh}] [22]. This cationic
palladium complex was obtained as a dark-orange solid and fully
characterized by elemental analysis and NMR spectroscopy. It was
3. Conclusions
We have described the synthesis of carbosilane dendrons with
bidentate phosphanes at the focal point and alkyl or dimethyla-
mino groups at the periphery following a synthetic procedure

92
S. Vigo et al. / Journal of Organometallic Chemistry 717 (2012) 88e98
[27], 4-bromo-N,N-bis(diphenylphosphanomethyl)aniline (PP:Br),
Ph2
P
Cl
Cl
[PdCl2(cod)]
THF
4-(bis(diphenylphosphanomethyl)amino)phenol (PP:OH) [18],
[PdCl2(cod)] (cod ¼ 1,5-cyclooctadiene) [28], and [PdCl2{(P(Ph)2-
CH2)2NPh}] [22] were prepared according to reported procedures.
Solvents were dried prior to use and distilled under argon, as
described elsewhere [29]. 1H, 13C, 31P, and 29Si NMR spectra were
recorded with Varian Gemini-200, Mercury VX-300, or UnityPlus-
Pd
dend
N
PP:Gn:Xm
P
Ph2
[PdCl2(PP:Gn:Xm)]
500 spectrometers. Chemical shifts (d, ppm) are quoted relative to
Ph2
SiMe4 (1H, 13C, and 29Si) or 85% H3PO4 (31P), and were measured by
internal referencing to the deuterated solvent (13C and residual 1H
resonances), or by the substitution method (31P and 29Si). Coupling
constants (J) are given in Hz. Elemental analyses were performed in
duplicate by the Analytical Laboratories of the University of Alcalá
with a LECO CHNS-932 microanalyzer. Chromatographic analysis
wereperformed using an HP-5890 Series II gas chromatograph fitted
with an Agilent DB-1-capillary column (15 m length, 0.25 mm
Cl
Cl
P
Me2N
Pd
S
N
Si
3Si
Me2
P
Ph2
[PdCl2(PP:G1:(NMe2)3)]
CH3I
CH2Cl2
3Si
internal diameter, 0.10
mm film thickness) under the following
Ph2
P
I
I
conditions: injector temperature, 250 ꢀC; detector temperature,
260 ꢀC; oven temperature program, isothermal 120 ꢀC/5 min.
I
Me3N
Pd
S
N
Si
Me2
P
Ph2
4.2. Synthesis of non-dendritic phosphanes and their complexes
PdI2(PP:G1:(NMe3I)3)
4.2.1. (Ph2PCH2)2N(C6H4O-4-SiMe3) (PP:OSiMe3)
Scheme 3. Synthesis of palladium complexes.
Triethylamine (0.073 mL, 0.53 mmol) and chlorotrimethylsilane
(0.067 mL, 0.53 mmol) were added to a solution of PP:OH (0.240 g,
0.48 mmol) in THF (15 mL). The mixture was stirred for 3 h and the
volatiles then evaporated under vacuum. Diethyl ether was added
to the residue and the ammonium salt filtered off. The solution was
evaporated under vacuum to afford an oily off-white solid identi-
fied as diphosphine PP:OSiMe3 (0.22 g, 78%). Anal. Calc. for
C35H37NOP2Si: C, 72.77; H, 6.46; N, 2.42. Found: C, 72.14; H, 6.12; N,
involving bifunctionalization of dendrons using activated phenyl
groups bonded to the core silicon atom as protecting groups. The
versatility of this synthetic strategy allows the deprotection step to
be performed at the right time during the synthesis depending on
the nature of the functionalities selected for the focal point and the
periphery. Palladium complexes of phosphine-functionalized car-
bosilane dendrons were also prepared and terminal dimethylamino
groups quaternized. These complexes were tested as catalysts in
the Heck reaction but they showed poor activities and stabilities,
giving extensive precipitation of palladium black.
2.31%. 1H NMR (CDCl3, 300 MHz):
d
¼ 7.29 (m, 20H, PC6H5), 6.69 (d,
3
3JH,H ¼ 8.9, 2H, C6H4), 6.62 (d, JH,H ¼ 8.9, 2H, C6H4), 4.01 (d,
2JP,H ¼ 4.03, 4H, CH2P), 0.22 ppm (s, 9H, SiCH3). 13C{1H} NMR (CDCl3,
75 MHz):
d
¼ 147.8 (C6H4O, Cipso), 143.6 (C6H4N, Cipso), 137.6 (d,
JC,P ¼ 14.9, PC6H5, Cipso), 133.1 (d, JC,P ¼ 20.4, PC6H5, Cortho) 128.5 (d,
JC,P ¼ 17.3, PC6H5, Cmeta), 128.3 (d, JC,P ¼ 6.1, PC6H5, Cpara) 120.2
4. Experimental
1
(C6H4O, Cortho), 117.8 (C6H4N, Cortho), 55.5 (dd, JC,P ¼ 13.6 and
4.1. Reagents and general techniques
3JC,P ¼ 8.1, CH2P), 0.2 ppm (s, SiCH3). 31P{1H} NMR (CDCl3,
202 MHz):
d
¼ ꢁ25.9 ppm.
All operations were performed under argon using Schlenk or dry-
box techniques. Unless otherwise stated, reagents were obtained
from commercial sources and used as received. Diallyl(methyl)
phenylsilane [26], trichloro(2,4,6-trimethoxyphenyl)silane [24],
trichloro(4-methoxyphenyl)silane, triallyl(4-methoxyphenyl)silane
4.2.2. (Ph2PCH2)2N(C6H4-4-SiMe3) (PP:SiMe3)
1.6 solution of n-butyllithium in hexane (0.60 mL,
A
M
0.92 mmol) was slowly added to a solution of PP:Br (0.350 g,
0.62 mmol) at ꢁ78 ꢀC in THF (20 mL). Stirring was continued at the
Table 1
Heck coupling of 4-iodotoluene and methyl acrylate in acetonitrile.a
[(PP)PdCl2] (1 mol%)
Ar
ArI
+
(NEt3H)I
+
COOMe
ArI = 4-iodotoluene
COOMe
C, NEt3
PP ligand
Conv. after 24 h [%]b
PhN(CH2PPh2)2
PP:SiMe3
PP:G1:(Et)2
PP:G1:(Et)3
PP:G2:(Et)4
PP:NMe2
44
60
50
54
62
41
15
56
PP:G1:(NMe2)3
PP:G1:(NMe3I)3
a
Conditions: 0.5 mmol of 4-iodotoluene, 0.5 mmol of methyl acrylate, 0.5 mmol of triethylamine, 5 mmol
(1 mol%) of Pd catalyst were reacted in 5 mL of acetonitrile at 80 ꢀC for 24 h. See Experimental section for details.
b
Conversions determined by Gas Chromatography using naphthalene as an internal standard.

S. Vigo et al. / Journal of Organometallic Chemistry 717 (2012) 88e98
93
same temperature for 15 min, then chlorotrimethylsilane (0.08 mL,
0.62 mmol) was added and the reaction mixture allowed to warm
to room temperature. The solvent was then removed under vacuum
and the residue extracted with hexane (3 ꢃ 10 mL). Evaporation of
the combined hexane solutions to dryness yielded PP:SiMe3 as an
oily off-white solid (0.26 g, 75%). Anal. Calc. for C35H37NP2Si: C,
74.84; H, 6.64; N, 2.49. Found: C, 75.08; H, 6.77; N, 2.34%. 1H NMR
room temperature. The orange solution was then evaporated under
vacuum and the residue washed with hexane (2 ꢃ 10 mL) to give
[PdCl2(PP:OH)] as an orange solid (0.17 g, 82%). Anal. Calc. for
C32H29Cl2NOP2Pd (682.8): C, 56.28; H, 4.28; N, 2.05. Found: C,
56.24; H, 4.61; N, 1.74%. 1H NMR ([D6]DMSO, 300 MHz):
d
¼ 7.85 (m,
8H, PC6H5), 7.51 (m, 12H, PC6H5), 6.49 (br., 4H, C6H4), 4.23 ppm (br.,
4H, CH2P). 13C{1H} NMR ([D6]DMSO, 75 MHz):
d
¼ 153.0 (C6H4O,
(CDCl3, 300 MHz):
d
¼ 7.33 (m, 22H, PC6H5 overlapped with 2H
Cipso), 143.9 (C6H4N, Cipso), 133.5 (d, JC,P ¼ 10.0, PC6H5, Cortho), 130.8
(s, PC6H5, Cpara), 127.8 (d, JC,P ¼ 10.5, PC6H5, Cmeta), 121.5 (C6H4N,
Cortho), 115.1 (C6H4O, Cortho), 54.3 ppm (d, JC,P ¼ 40.9, NCH2P). 31P
signal of C6H4), 6.84 (d, 3JH,H ¼ 8.8, 2H, C6H4), 3.93 (d, 2JH,P ¼ 4.4, 4H,
NCH2P), 0.25 ppm (s, 9H, SiCH3). 13C{1H} NMR (CDCl3, 75 MHz):
d
¼ 148.1 (C6H4N, Cipso), 137.3 (d, JC,P ¼ 15.3, PC6H5, Cipso), 134.2
{1H} NMR ([D6]DMSO, 202 MHz):
d
¼ 10.0 ppm.
(C6H4Si, Cortho), 133.2, (d, JC,P ¼ 18.4, PC6H5, Cortho), 128.6 (d,
JC,P ¼ 17.2, PC6H5, Cmeta), 128.4 (d, JC,P ¼ 6.5, PC6H5, Cpara), 126.6
4.2.5. [PdCl2{(Ph2PCH2)2N(C6H4-4-Br)}] ([PdCl2(PP:Br)])
1
(C6H4Si, Cipso), 113.5 (C6H4N, Cortho), 53.7 (dd, JC,P ¼ 14.9 and
This complex was obtained as a slightly yellow solid (0.32 g,
75%) as described above in Section 4.2.4, starting from PP:Br
(0.330 g, 0.58 mmol) and [PdCl2(cod)] (0.16 g, 0.58 mmol). Anal.
Calc. for C32H28BrCl2NP2Pd: C, 51.54; H, 3.78; N, 1.88. Found: C,
3JC,P ¼ 6.5, NCH2P), ꢁ0.8 ppm (s, SiCH3). 31P{1H} NMR (CDCl3,
202 MHz):
d
¼ ꢁ27.8 ppm.
4.2.3. (Ph2PCH2)2N(C6H4-4-SiMe2CH2SCH2CH2NMe2) (PP:NMe2)
1.6 solution of n-butyllithium in hexane (1.10 mL,
50.99; H, 3.73; N, 1.92%. 1H NMR (CDCl3, 300 MHz):
d
¼ 7.32 (m,
3
A
M
8H, PC6H5), 7.44 (m, 12H, PC6H5), 7.26 (d, JH,H ¼ 8.9, 2H, C6H4),
3
1.76 mmol) was slowly added to a solution of PP:Br (1.00 g,
1.76 mmol) at ꢁ78 ꢀC in THF (20 mL). The reaction mixture was
stirred for 15 min and then an excess of chloromethyl(dimethyl)
chlorosilane (0.30 mL, 2.21 mmol) in THF (5 mL) was added at
ꢁ78 ꢀC. The reaction mixture was allowed to warm slowly to room
temperature and then the solvent was removed under vacuum. The
residue was extracted with hexane (2 ꢃ 10 mL) and the combined
hexane solutions evaporated to dryness under vacuum to give the
intermediate C6H4{1-N(CH2PPh2)2}(4-SiMe2CH2Cl) as a spectro-
scopically pure colorless oil which was used without further puri-
6.45 (d, JH,H ¼ 8.9, 2H, C6H4), 3.92 (br., 4H, NCH2P). 13C{1H}
NMR (CDCl3, 75 MHz):
d
¼
150.2 (C6H4O, Cipso), 133.9 (d,
JC,P ¼ 10.5, PC6H5, Cortho), 132.7 (C6H4Br, Cortho), 131.9 (s, PC6H5,
Cpara), 128.9 (d, JC,P ¼ 11.8, PC6H5, Cmeta), 128.6 (C6H4Br, Cipso),
127.8 (d, JC,P ¼ 57.6, PC6H5, Cipso) 120.2 (C6H4N, Cortho), 53.4 (dd,
3
1JC,P ¼ 47.1, JC,P ¼ 3.6, NCH2P). 31P{1H} NMR (CDCl3, 202 MHz):
d
¼ 10.0 ppm.
4.2.6. [PdCl2{(Ph2PCH2)2N(C6H4-4-OSiMe3)}] ([PdCl2(PP:OSiMe3)])
This complex was obtained as an orange solid (0.09 g, 87%)
(0.32 g, 75%) as described in Section 4.2.4, starting from PP:OSiMe3
(0.080 g, 0.14 mmol) and [PdCl2(cod)] (0.040 g, 0.14 mmol). Anal.
Calc. for C35H37Cl2NOP2PdSi: C, 55.68; H, 4.94; N, 1.86. Found: C,
fication.
Spectroscopic
data
for
C6H4{1-N(CH2PPh2)2}(4-
SiMe2CH2Cl): 1H NMR (C6D6, 300 MHz):
d
¼ 7.30 (m, 12H, PC6H5),
3
7.03 (m, 8H, PC6H5), 7.27 (d, JH,H ¼ 8.8, 2H, C6H4), 6.90 (d,
3JH,H ¼ 8.8, 2H, C6H4), 4.05 (d, JH,P ¼ 4.5, 4H, NCH2P), 2.72 (s, 2H,
55.95; H, 4.71; N, 1.99%. 1H NMR (CDCl3, 300 MHz):
d
¼ 7.85 (m, 8H,
2
SiCH2Cl), 0.30 ppm (s, 6H, SiCH3). 13C{1H} NMR (C6D6, 75 MHz):
P(C6H5)2), 7.41 (m, 12H, P(C6H5)2), 6.68 (d, JH,H ¼ 8.6, 2H, C6H4),
3
d
¼ 149.5 (C6H4N, Cipso), 138.0 (d, JC,P ¼ 16.2, PC6H5, Cipso),135.1
6.60 (d, 3JH,H ¼ 8.6, 2H, C6H4), 3.82 (br., 4H, NCH2P), 0.20 ppm (s, 9H,
(C6H4Si, Cortho), 133.6 (d, JC,P ¼ 19.9, PC6H5, Cortho), 128.9 (d,
JC,P ¼ 14.0, PC6H5, Cmeta), 128.7 (d, JC,P ¼ 5.9, PC6H5, Cpara), 114.4
(C6H4N, Cortho), 54.0 (d, JC,P ¼ 8.8, NCH2P), 30.9 (SiCH2Cl), ꢁ4.4 ppm
SiCH3). 13C{1H} NMR (CDCl3, 75 MHz):
d
¼ 152.4 (C6H4O, Cipso),146.7
(C6H4N, Cipso), 134.0 (d, JC,P ¼ 10.5, PC6H5, Cortho), 131.6 (s, PC6H5,
Cpara), 128.7(d, JC,P ¼ 11.4, PC6H5, Cmeta), 128.3 (d, JC,P ¼ 57.0, PC6H5,
Cipso), 122.5 and 121.1 (C6H4N, Cortho and Cmeta), 56.5 (d, JC,P ¼ 46.4,
NCH2P), 0.1 ppm (SiCH3). 31P{1H} NMR (CDCl3, 202 MHz):
(SiCH3). 31P{1H} NMR (C6D6, 202 MHz):
d
¼ ꢁ27.1 ppm. 1He29Si
gHMBC (C6D6):
d
¼ ꢁ4.4 ppm.
Subsequently, a deoxygenated aqueous solution (5 mL) of NaOH
(0.260 g, 98% purity, 6.37 mmol) and 2-(dimethylamino)ethane-
thiol hydrochloride (0.270 g, 1.92 mmol) was added to a solution of
the above intermediate (1.09 g, 1.84 mmol) in deoxygenated
ethanol (20 mL). This mixture was stirred at 80 ꢀC overnight. The
reaction mixture was then cooled to room temperature and
extracted with diethyl ether (3 ꢃ 10 mL). The combined diethyl
ether solutions were dried over MgSO4 and evaporated to dryness
to give PP:NMe2 as a slightly yellow oil (0.84 g, 69%). Anal. Calc. for
C39H46N2P2SSi: C, 70.45; H, 6.97; N, 4.21; S, 4.82. Found: C, 70.15; H,
d
¼ 10.7 ppm.
4.2.7. [PdCl2{(Ph2PCH2)2N(C6H4-4-SiMe3)}] ([PdCl2(PP:SiMe3)])
This complex was obtained as a yellow solid (0.13 g, 74%) as
described in Section 4.2.4, starting from PP:SiMe3 (0.130 g,
0.24 mmol) and [PdCl2(cod)] (0.070 g, 0.24 mmol). Anal. Calc. for
C35H37Cl2NP2PdSi: C, 56.88; H, 5.05; N, 1.90. Found: C, 56.40; H,
4.96, N, 1.85%. 1H NMR (CDCl3, 300 MHz):
d
¼ 7.85 (m, 8H, PC6H5),
3
7.46 (m, 12H, PC6H5), 7.32 (d, JH,H ¼ 8.5, 2H, C6H4), 6.63 (d,
3JH,H ¼ 8.5, 2H, C6H4), 3.94 (br., 4H, NCH2P), 0.19 ppm (s, 9H, SiCH3).
7.02; N, 3.96, S, 4.78%. 1H NMR (CDCl3, 300 MHz):
d
¼ 7.30 (m, 22H,
13C{1H} NMR (CDCl3, 75 MHz):
d
¼ 151.9 (C6H4N, Cipso), 134.9
3
PC6H5 overlapped with 2H signal of C6H4), 6.79 (d, JH,H ¼ 8.5, 2H,
C6H4), 3.87 (d, 2JH,P ¼ 4.6, 4H, NCH2P), 2.56 (m, 4H, SCH2CH2NMe2),
2.23 (s, 6H, N(CH3)2), 1.97 (s, 2H, SiCH2S), 0.32 ppm (s, 6H, SiCH3).
(C6H4Si, Cortho), 133.9 (d, JC,P ¼ 9.9, PC6H5, Cortho), 131.8 (s, PC6H5,
Cpara), 129.8 (C6H4Si Cipso), 128.8 (d, JC,P ¼ 11.2, PC6H5, Cmeta), 128.1
(d, JC,P ¼ 57.7, PC6H5, Cipso), 118.2 (s, C6H4N, Cortho), 53.8 (d,
JC,P ¼ 43.4, NCH2P), ꢁ1.2 ppm (s, SiCH3). 31P{1H} NMR (CDCl3,
13C{1H} NMR (CDCl3, 75 MHz):
JC,P ¼ 15.0, PC6H5, Cipso), 134.6 (C6H4Si, Cortho), 133.2 (d, JC,P ¼ 18.6,
PC6H5, Cortho), 128.7 (d, JC,P ¼ 19.4, PC6H5, Cmeta), 128.5 (d, JC,P ¼ 6.2,
PC6H5, Cpara), 113.4 (C6H4N, Cortho), 58.3 (SCH2CH2N), 53.6 (d,
d
¼ 148.5 (C6H4N, Cipso), 137.3 (d,
202 MHz):
d
¼ 9.9 ppm.
4.2.8. [PdCl2{(Ph2PCH2)2N(C6H4-4-SiMe2CH2SCH2CH2NMe2)}]
([PdCl2(PP:NMe2)])
JC,P
¼
8.5, NCH2P), 44.6 (N(CH3)2), 33.7 (SCH2CH2N), 18.5
(SiCH2S), ꢁ3.1 ppm (SiCH3). 31P{1H} NMR (CDCl3, 202 MHz):
This complex was obtained as a yellow solid (1.27 g, 86%). as
described in Section 4.2.4, starting from PP:NMe2 (1.16 g,
1.75 mmol) and [PdCl2(cod)] (0.500 g, 1.75 mmol). However, in this
case the reagents were mixed at ꢁ78 ꢀC instead of room temper-
ature and the residue was washed with pentane instead of hexane.
Anal. Calc. for C39H46Cl2N2P2PdSSi: C, 55.62; H, 5.51; N, 3.33; S, 3.81.
d
¼ ꢁ27.8 ppm.
4.2.4. [PdCl2{(Ph2PCH2)2N(C6H4-4-OH)}] ([PdCl2(PP:OH)])
A solution of [PdCl2(cod)] (0.090 g, 0.31 mmol) in CH2Cl2 and
PP:OH (0.160 g, 0.31 mmol) in CH2Cl2 (10 mL) was stirred for 3 h at

94
S. Vigo et al. / Journal of Organometallic Chemistry 717 (2012) 88e98
Found: C, 55.84; H, 5.28; N, 2.99; S, 3.96%. 1H NMR (CDCl3,
4.3.3. (C6H4-4-OMe)(CH2CH2CH2SiMe2Et)3 (Ar:G1:(Et)3)
300 MHz):
d
¼ 7.84 (m, 8H, PC6H5), 7.43 (m, 14H, PC6H5 overlapped
This compound was synthesized as described above for
Ar:G1:(Et)2, starting from triallyl(4-methoxyphenyl)silane (1.50 g,
5.8 mmol) and chloro(dimethyl)silane (2.50 mL, 22.7 mmol) for the
hydrosilylation step, and subsequent treatment with ethyl-
magnesium chloride (11.40 mL, 22.8 mmol). Ar:G1:(Et)3 was iso-
lated as a colorless oil (2.61 g, 86%). Anal. Calc. for C28H58OSi4: C,
64.29; H, 11.18. Found: C, 64.12; H, 11.18. 1H NMR (CDCl3, 300 MHz):
with 2H signal of C6H4), 6.60 (d, 3JH,H ¼ 8.5, 2H, C6H4), 3.95 (br., 4H,
NCH2P), 2.50 (m, 4H, SCH2CH2NMe2), 2.20 (s, 6H, N(CH3)2), 1.93 (s,
2H, SiCH2S), 0.29 ppm (s, 6H, SiCH3). 13C{1H} NMR (CDCl3, 75 MHz):
d
¼ 152.1 (s, C6H4N, Cipso), 135.2 (s, C6H4Si, Cortho), 133.9 (d,
JC,P ¼ 10.7, PC6H5, Cortho), 131.8 (s, PC6H5, Cpara), 128.8 (d, JC,P ¼ 11.5,
PC6H5, Cmeta), 127.9 (d, JC,P ¼ 57.6, PC6H5, Cipso) 117.9 (C6H4N, Cortho),
58.8 (s, SCH2CH2N), 53.3 (d, JC,P ¼ 47.6, NCH2P), 45.3 (s, N(CH3)2),
34.2 (s, SCH2CH2N), 18.0 (s, SiCH2S), ꢁ3.1 ppm (s, (SiCH3)). 31P{1H}
d
¼ 7.37 (d, 3JH,H ¼ 7.7, 2H, C6H4), 6.88 (d, 3JH,H ¼ 7.7, 2H, C6H4), 3.80
3
(s, 3H, CH3O), 1.35 (m, 6H, SiCH2CH2CH2Si), 0.89 (t, JH,H ¼ 8.0, 9H,
SiCH2CH3), 0.81 (m, 6H, SiCH2CH2CH2SiEt), 0.56 (m, 6H,
SiCH2CH2CH2SiEt), 0.43 (q, 3JH,H ¼ 8.0, 6H, SiCH2CH3), ꢁ0.09 ppm (s,
NMR (CDCl3, 202 MHz):
¼ ꢁ4.2 ppm.
d
¼ 10.0 ppm. 1He29Si gHMBC (CDCl3):
d
18H, Si(CH3)2). 13C{1H} NMR (CDCl3, 75 MHz):
d
¼ 160.0 (C6H4O,
4.3. Synthesis of dendritic phosphanes and their complexes
Cipso), 128.9 (C6H4Si, Cipso), 135.4 (C6H4Si, Cortho), 113.4 (C6H4O, Cor-
tho), 54.9 (CH3O), 19.8, 18.4 and 17.6 (SiCH2CH2CH2Si), 7.3 and 7.0
4.3.1. Triallyl(2,4,6-trimethoxyphenyl)silane
(SiCH2CH3), ꢁ3.8 ppm (Si(CH3)2). 1He29Si gHMBC (CDCl3):
(SiCH2CH3), ꢁ4.5 ppm (SiC6H4).
d
¼ 2.8
A solution of trichloro(2,4,6-trimethoxyphenyl)silane (17.85 g,
59.2 mmol)inTHF (100 mL) was slowlyadded via a dropping funnel to
a 1 M diethyl ether solution of allylmagnesium bromide (180 mL,
180 mmol) in 50 mL of diethyl ether at 0 ꢀC. The mixture was subse-
quently heated at reflux for 4 h, then cooled to room temperature and
hydrolyzed with a saturated aqueous solution of ammonium chloride.
The ethereal phasewas decanted and the aqueous phasewashed with
diethyl ether (3 ꢃ 20mL). The combined ethereal solutions were dried
overMgSO4 and filtered. The solvent wasthen removed under vacuum
to yield the title compound as a slightly brown oil (16.21 g, 86%). Anal.
Calc. for C18H26O3Si: C, 67.88; H, 8.23. Found: C, 67.36; H, 7.88%. 1H
4.3.4. (C6H4-2,4,6-(OMe)3)Si(CH2CH2CH2SiMe2(CH2Cl))3
(Ar:G1:(CH2Cl)3)
Triallyl(2,4,6-trimethoxyphenyl)silane (0.440 g, 1.40 mmol)
was combined with chloromethyl(dimethyl)silane (0.52 mL,
4.26 mmol) in a 25 mL ampoule fitted with a PTFE stopcock. Three
drops of the Karstedt catalyst (3e3.5% based on Pt of a plat-
inum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex solu-
tion) were added. After stirring overnight, all volatiles were
removed under reduced pressure to leave a slightly yellow oil that
was identified as Ar:G1:(CH2Cl)3 (0.90 g, 98%). Anal. Calc. for
C28H55Cl3O3Si4: C, 51.08; H, 8.42. Found: C, 51.10; H, 8.21%. 1H NMR
NMR (CDCl3, 300 MHz):
d
¼ 6.04 (s, 2H, C6H2), 5.78 (m, 3H,
Si(CH2eCH]CH2)3), 4.79 (m, 6H, Si(CH2eCH]CH2)3), 3.79 (s, 3H,
OCH3), 3.71 (s, 6H, OCH3), 1.86 (m, 6H, Si(CH2eCH]CH2)3). 13C{1H}
(CDCl3, 300 MHz):
d
¼ 6.04 (s, 2H, C6H2), 3.80 (s, 3H, OCH3), 3.70
NMR (CDCl3, 75 MHz):
d
¼ 166.5 and 163.4 (C6H2O3, Cipso), 135.8
(s, 6H, OCH3), 2.72 (s, 6H, SiCH2Cl), 1.33 (m, 6H, SiCH2CH2CH2Si),
0.85 (m, 6H, C6H2SiCH2CH2CH2Si), 0.67 (m, 6H, C6H2-
SiCH2CH2CH2Si), 0.05 ppm (s, 18H, SiCH3). 13C{1H} NMR (CDCl3,
(CH2CH]CH2), 112.9 (CH2CH]CH2), 101.1 (C6H2Si, Cipso), 90.1 (C6H2),
55.0 and 54.9 (CH3O), 21.4 (CH2CH]CH2). 1He29Si gHMBC (CDCl3):
d
¼ ꢁ7.8 ppm.
75 MHz):
d
¼
166.5 and 163.1 (C6H2(OCH3)3, Cipso), 92.9
(C6H2Si, Cipso), 90.1 (C6H2Si, Cmeta), 55.1 and 55.0 (OCH3), 30.6
(SiCH2Cl), 19.2, 18.6 and 18.5 (SiCH2CH2CH2Si), ꢁ4.5 ppm
4.3.2. (C6H5)SiMe(CH2CH2CH2SiMe2Et)2 (Ar:G1:(Et)2)
A
5.6 solution of tetrabutylammonium hexa-
10ꢁ3
ꢃ
M
(Si(CH3)2). 1He29Si gHMBC (CDCl3):
(SiC6H2).
d
¼ 3.2 (SiCH2Cl), ꢁ4.2 ppm
chloroplatinate(IV) in dichloromethane (1.0 mL, 5.6 mmol) and an
excess of chloro(dimethyl)silane (1.8 mL, 16.9 mmol) were added
via a syringe to diallyl(methyl)phenylsilane (1.140 g, 5.65 mmol) in
a 25 mL ampoule fitted with a PTFE stopcock. The solution was
stirred at room temperature until the reaction was complete (ca.
6 h, 1H NMR monitoring), then the excess of silane and other
volatiles were removed under vacuum. The crude product was
dissolved in THF (20 mL) and added dropwise (15 min) to an ice-
cooled 2.0 M THF solution of ethylmagnesium chloride (8.5 mL,
17.0 mmol) diluted in THF (20 mL). After the addition had finished,
the reaction mixture was allowed to reach room temperature and
stirring was continued overnight. The excess ethylmagnesium
chloride was hydrolyzed with a concentrated aqueous solution of
ammonium chloride (50 mL). The organic phase was separated by
decantation, and the aqueous solution washed with diethyl ether
(3 ꢃ 15 mL). The combined organic extracts were dried with
anhydrous MgSO4, filtered off, and evaporated in vacuo to yield
Ar:G1:(Et)2 as a colorless oil (1.65 g, 77%). Anal. Calc. for C21H42Si3:
C, 66.58; H, 11.18. Found: C, 66.11; H, 10.96%. 1H NMR (CDCl3,
4.3.5. ClSiMe(CH2CH2CH2SiEtMe2)2 (Cl:G1:(Et)2)
Compound Ar:G1:(Et)2 (1.64 g, 4.33 mmol) was dissolved in
toluene (5 mL). Trifluoromethanesulfonic acid (0.38 mL,
4.33 mmol) was then added dropwise from a syringe to the above
solution previously cooled to 0 ꢀC. Stirring was continued for
15 min at room temperature, and an excess of lithium chloride
(0.730 g, 17.3 mmol) was then added. After stirring the reaction
mixture for 1 h, the volatiles were removed in vacuo and the
residue extracted with hexane (10 mL). The mixture was then
filtered and the solvent evaporated to yield Cl:G1:(Et)2 as a color-
less oil (1.43 g, 98%). Anal. Calc. for C15H37ClSi3: C, 53.43; H, 11.06.
Found: C, 53.64; H, 11.23%. 1H NMR (CDCl3, 300 MHz):
d
¼ 1.41 (m,
3
4H, SiCH2CH2CH2Si), 0.87 (t, JH,H ¼ 8.0, 6H, CH2CH3), 0.82 (m, 4H,
ClSiCH2CH2CH2Si), 0.56 (m, 4H, ClSiCH2CH2CH2Si), 0.46 (q,
3JH,H ¼ 8.0, 4H, CH2CH3), 0.34 (s, 3H, SiCH3), ꢁ0.07 ppm (s, 12 H,
Si(CH3)2). 13C{1H} NMR (CDCl3, 75 MHz):
d
¼ 22.3, 19.1 and 17.6
(SiCH2CH2CH2Si), 7.4 and 6.9 (CH2CH3), 0.2 (SiCH3), ꢁ3.9 ppm
300 MHz):
d
¼ 7.45 (m, 2H, C6H5), 7.33 (m, 3H, C6H5), 1.35 (m, 4H,
(Si(CH3)2). 1He29Si gHMBC (CDCl3):
(Si(CH3)2).
d
¼ 31.4 (SiCl), 3.2 ppm
3
SiCH2CH2CH2Si), 0.85 (t, JH,H ¼ 7.9, 6H, CH2CH3), 0.81 (m, 4H,
PhSiCH2CH2CH2Si), 0.55 (m, 4H, SiCH2CH2CH2SiEt), 0.44 (q,
3JH,H ¼ 7.9, 4H, CH2CH3), 0.23 (s, 3H, PhSiCH3), ꢁ0.09 ppm (s, 12 H,
4.3.6. ClSi(CH2CH2CH2SiEtMe2)3 (Cl:G1:(Et)3)
Si(CH3)2). 13C{1H} NMR (CDCl3, 75 MHz):
d
¼ 139.0 (C6H5Si, Cipso),
This compound was synthesized as a pale-brown oil (0.44 g,
99%) following the procedure described above for Cl:G1:(Et)2,
starting from Ar:G1:(Et)3 (0.500 g, 0.98 mmol), tri-
fluoromethanesulfonic acid (0.10 mL, 1.17 mmol), and lithium
chloride (0.130 g, 3 mmol). Anal. Calc. for C21H51ClSi4: C, 55.87; H,
133.8 (C6H5Si, Cortho), 128.6 (C6H5Si, Cpara), 127.6 (C6H5Si, Cmeta),
19.6, 18.9 and 18.4 (SiCH2CH2CH2Si), 7.4 and 7.0 (CH2CH3), ꢁ3.8
(Si(CH3)2), ꢁ4.9 ppm (C6H5SiCH3). 1He29Si gHMBC (CDCl3):
(Si(CH3)2), ꢁ3.6 ppm (SiC6H5).
d
¼ 3.2

S. Vigo et al. / Journal of Organometallic Chemistry 717 (2012) 88e98
95
11.39. Found: C, 55.87; H, 11.86%. 1H NMR (CDCl3, 300 MHz):
C
ipso), 134.9 (C6H4Si, Cortho), 133.3 (d, JC,P ¼ 18.6, PC6H5, Cortho), 128.6
3
d
¼ 1.41 (m, 6H, SiCH2CH2CH2Si), 0.90 (t, JH,H ¼ 8.1, 9H, CH2CH3),
(d, JC,P ¼ 21.7, PC6H5, Cmeta), 128.4 (s, PC6H5, Cpara), 124.4 (C6H4Si,
Cipso), 113.4 (C6H4N, Cortho), 53.6 (d, JC,P ¼ 8.0, NCH2P), 19.9, 18.5 and
17.8 (SiCH2CH2CH2Si), 7.4 and 7.1 (CH2CH3), ꢁ3.7 ppm (SiCH3). 31P
0.84 (m, 6H, SiCH2CH2CH2SiEt), 0.57 (m, 6H, SiCH2CH2CH2SiEt), 0.45
(q, 3JH,H ¼ 8.1, 6H, CH2CH3), ꢁ0.07 ppm (s, 18H, SiCH3). 13C{1H} NMR
(CDCl3, 75 MHz):
d
¼ 21.0, 19.2 and 17.7 (SiCH2CH2CH2Si), 7.3 and
{1H} NMR (C6D6, 202 MHz):
d
¼ ꢁ26.2 ppm. 1He29Si gHMBC (C6D6):
6.9 (CH2CH3), ꢁ3.9 ppm (SiCH3). 1He29Si gHMBC (CDCl3):
(SiCl), 2.8 ppm (SiCH3).
d
¼ 29.8
d
¼ 2.8 (SiCH3), ꢁ4.8 ppm (SiC6H4).
4.3.10. (Ph2PCH2)2N(C6H4-4-SiMe((CH2)3SiMe(CH2)3SiEtMe2)2)
PP:G2:(Et)4
4.3.7. ClSi(CH2CH2CH2SiMe2(CH2Cl))3 (Cl:G1:(CH2Cl)3)
Compound Ar:G1:(CH2Cl)3 (0.680 g, 1.04 mmol) was dissolved
in 20 mL of diethyl ether and an excess of hydrogen chloride in the
form of a 1 M diethyl ether solution (1.20 mL, 1.2 mmol) was added
via a syringe. The solution was stirred at room temperature for
30 min and then evaporated under vacuum. 1,3,5-
Trimethoxybenzene was removed by sublimation at 120 ꢀC and
1 mbar of pressure to leave a brown oil that was subsequently
identified as Cl:G1:(CH2Cl)3 (0.52 g, 96%). Anal. Calc. for
C19H44Cl4Si4: C, 43.33; H, 8.42. Found: C, 43.03; H, 8.20%. 1H NMR
This compound was obtained as a slightly yellow oil (0.76 g,
92%) following the procedure described above for PP:G1:(Et)2,
starting from 4-bromo-N,N-bis(diphenylphosphanomethyl)aniline
(0.39 g, 0.68 mmol), n-butyllithium (0.43 mL, 0.68 mmol) and
the second generation dendron Cl:G2:(Et)4 (0.52 g, 0.68 mmol),
which was prepared following similar procedure to those re-
ported previously [14,16]. This compound was obtained with
small amounts of Cl:G2:(Et)6 and PhN(CH2PPh2)2 but was used
without prior purification. 1H NMR (CDCl3, 300 MHz):
d
¼ 7.29
(CDCl3, 300 MHz):
d
¼ 2.76 (s, 6H, SiCH2Cl), 1.46 (m, 6H,
(m, 22H, PC6H5 overlapped with 2H signal of C6H4), 6.77 (d,
3JH,H ¼ 8.3, 2H, C6H4), 3.88 (br., 4H, NCH2P), 1.30 (m, 12H,
SiCH2CH2CH2Si), 0.86 (m, 6H, ClSiCH2CH2CH2Si), 0.72 (m, 6H,
ClSiCH2CH2CH2Si), 0.10 ppm (s, 18H, SiCH3). 13C{1H} NMR
SiCH2CH2CH2Si), 0.89 (t, JH,H ¼ 7.9, 12H, SiCH2CH3), 0.75 (m,
3
(CDCl3, 75 MHz):
d
¼
30.3 (SiCH2Cl), 20.7, 17.9 and 17.5
4H, C6H4SiCH2CH2CH2Si), 0.53 (m, 20H, SiCH2CH2CH2Si), 0.44 (q,
3JH,H ¼ 7.9, 8H, SiCH2CH3), 0.16 (s, 3H, C6H4SiCH3), 0.08 (s, 24H,
Si(CH3)2), ꢁ0.10 ppm (s, 6H, SiCH3). 13C{1H} NMR (CDCl3,
(SiCH2CH2CH2Si), ꢁ4.5 ppm (SiCH3). 1He29Si gHMBC (CDCl3):
d
¼ 30.3 (SiCl), 3.3 ppm (SiCH2Cl).
75 MHz):
d
¼ 148.2 (C6H4N, Cipso), 137.3 (d, JC,P ¼ 15.3, PC6H5,
4.3.8. (Ph2PCH2)2N(C6H4-4-SiMe(CH2CH2CH2SiEtMe2)2)
(PP:G1:(Et)2)
Cipso), 134.7 (C6H4Si, Cortho), 133.2 (d, JC,P ¼ 21.2, PC6H5, Cortho),
128.5 (d, JC,P ¼ 23.6, PC6H5, Cmeta), 128.4 (s, PC6H5, Cpara), 113.5
1
3
A
1.6
M
solution of n-butyllithium in hexane (0.98 mL,
(s, C6H4N, Cortho), 53.8 (dd, JC,P ¼ 24.8, JC,P ¼ 7.4, NCH2P), 19.7,
1.56 mmol) was slowly added to a solution of 4-bromo-N,N-bis(-
diphenylphosphanomethyl)aniline (0.890 g, 1.56 mmol) at ꢁ78 ꢀC
in THF (15 mL). Stirring was continued at the same temperature for
15 min, then a solution ofCl:G1:(Et)2 (0.08 mL, 0.62 mmol) was
added and the reaction mixture allowed to warm to room
temperature. The solvent was then removed under vacuum and the
residue extracted with hexane (3 ꢃ 10 mL). Evaporation of the
hexane solution to dryness yielded PP:G1:(Et)2 as a slightly yellow
oil (0.99 g, 81%). Anal. Calc. for C47H65NP2Si3: C, 71.44; H, 8.29; N,
18.5
and
17.9
(SiCH2CH2CH2SiEt),
19.5,
18.7
and
17.7 (C6H4SiCH2CH2CH2Si), 7.4 and 7.0 (SiCH2CH3), ꢁ3.8
(Si(CH3)2), ꢁ4.9 ppm (C6H4SiCH3 and SiCH3 overlapped). 31P{1H}
NMR (CDCl3, 202 MHz):
d
¼
ꢁ27.5 ppm. 1He29Si gHMBC
(CDCl3):
d
¼ 3.2 (SiEt), 1.3 (SiMe), ꢁ4.5 ppm (SiC6H4).
4.3.11. (Ph2PCH2)2N(C6H4-4-Si(CH2CH2CH2SiMe2(CH2Cl))3)
(PP:G1:(CH2Cl)3)
This compound was isolated as a pale-yellow oil (1.89 g, 94%)
following the procedure described above for PP:G1:(Et)2, starting
from 4-bromo-N,N-bis(diphenylphosphanomethyl)aniline (1.16 g,
2.05 mmol), n-butyllithium (0.82 mL, 2.05 mmol) and
Cl:G1:(CH2Cl)3 (1.19 g, 2.27 mmol). Anal. Calc. for C51H72Cl3NP2Si4:
C, 62.52; H, 7.41; N, 1.43. Found: C, 62.49; C, 7.38; N, 1.45%. 1H NMR
1.77. Found: C, 70.98, H, 8.34; N, 1.79%. 1H NMR (CDCl3, 300 MHz):
3
d
¼ 7.30 (m, 20H, PC6H5), 7.27 (d, JH,H ¼ 8.6, 2H, C6H4), 6.77 (d,
3JH,H
¼
8.6, 2H, C6H4), 3.89 (br., 4H, NCH2P), 1.33 (m, 4H,
3
SiCH2CH2CH2Si), 0.89 (t, JH,H ¼ 8.0, 6H, CH2CH3), 0.75 (m, 4H,
SiCH2CH2CH2SiEt), 0.55 (m, 4H, SiCH2CH2CH2SiEt), 0.45 (q,
3JH,H ¼ 8.0, 4H, CH2CH3), 0.16 (s, 3H, C6H4SiCH3), ꢁ0.08 (s, 12 H,
(CDCl3, 300 MHz):
d
¼ 7.30 (m, 20H, PC6H5), 7.21 (d, 3JH,H ¼ 8.6, 2H,
Si(CH3)2). 13C{1H} NMR (CDCl3, 75 MHz):
d
¼ 148.1 (C6H4N, Cipso),
C6H4), 6.76 (d, 3JH,H ¼ 8.6, 2H, C6H4), 3.89 (d, 2JH,P ¼ 3.6, 4H, NCH2P),
2.75 (s, 6H, SiCH2Cl), 1.34 (m, 6H, SiCH2CH2CH2Si), 0.79 (m, 6H,
C6H4SiCH2CH2CH2Si), 0.70 (m, 6H, C6H4SiCH2CH2CH2Si), 0.08 ppm
137.5 (d, JC,P ¼ 15.3, PC6H5, Cipso), 134.7 (C6H4Si, Cortho), 133.2 (d,
JC,P ¼ 19.1, PC6H5, Cortho), 128.8 (d, JC,P ¼ 16.9, PC6H5, Cmeta), 128.4 (d,
JC,P ¼ 6.2, PC6H5, Cpara), 125.2 (C6H4Si, Cipso), 113.4 (C6H4N, Cortho),
(s, 18H, SiCH3). 13C{1H} NMR (CDCl3, 75 MHz):
d
¼ 148.1 (C6H4N,
1
3
53.6 (dd, JC,P ¼ 18.4 and JC,P ¼ 8.4, NCH2P), 19.7, 19.3 and 18.5
(SiCH2CH2CH2Si), 7.5 and 7.1 (CH2CH3), ꢁ3.7 (Si(CH3)2), ꢁ4.6 ppm
Cipso), 137.3 (d, JC,P ¼ 15.3, PC6H5, Cipso), 134.9 (C6H4Si, Cortho), 133.2
(d, JC,P ¼ 18.4, PC6H5, Cortho), 128.6 (d, JC,P ¼ 17.7, PC6H5, Cmeta), 128.4
(d, JC,P ¼ 6.1, PC6H5, Cpara), 123.2 (C6H4Si, Cipso), 113.4 (s, C6H4N,
Cortho), 53.5 (d, JC,P ¼ 8.4, NCH2P), 30.6 (CH2Cl), 18.6, 18.3 and 17.5
(SiCH2CH2CH2Si), ꢁ4.4 ppm (SiCH3). 31P{1H} NMR (CDCl3,
(C6H4SiCH3). 31P{1H} NMR (CDCl3, 202 MHz):
d
¼ ꢁ26.6 ppm.
1He29Si gHMBC (CDCl3):
d
¼ 2.9 (SiCH2CH3), ꢁ4.8 ppm (SiC6H4).
4.3.9. (Ph2PCH2)2N(C6H4-4-Si(CH2CH2CH2SiMe2Et)3) (PP:G1:(Et)3)
This compound was obtained as a slightly yellow oil (1.16 g, 92%)
following the procedure described above for PP:G1:(Et)2, starting
from 4-bromo-N,N-bis(diphenylphosphanomethyl)aniline (0.790 g,
1.39 mmol), n-butyllithium (0.90 mL, 1.39 mmol) and Cl:G1:(Et)3
(0.630 g, 1.39 mmol). Anal. Calc. for C53H79NP2Si4: C, 70.38; H, 8.80;
202 MHz):
(SiCH2Cl), ꢁ4.8 ppm (SiC6H4).
d
¼ ꢁ27.5 ppm. 1He29Si gHMBC (CDCl3):
d
¼ 3.4
4.3.12. (Ph2PCH2)2N(C6H4-4-Si(CH2CH2CH2SiMe2(CH2S(CH2)2
NMe2))3) (PP:G1:(NMe2)3)
This compound was isolated as a slightly yellow oil (1.48 g, 86%)
following the procedure described above for PP:NMe2, starting
from PP:G1:(CH2Cl)3 (1.40 g, 1.45 mmol), 2-(dimethylamino)etha-
nethiol hydrochloride (0.640 g, 4.49 mmol) and NaOH (0.890 g,
21.8 mmol). Anal. Calc. for C63H102N4P2S3Si4: C, 63.80; H, 8.67; N,
4.62; S, 8.11. Found: C, 63.85; H, 8.75, N, 4.71; S, 8.09%. 1H NMR
N, 1.55. Found: C, 70.29; H, 8.83; N, 1.52%. 1H NMR (C6D6, 300 MHz):
3
d
¼ 7.30 (m, 20H, PC6H5), 7.23 (d, JH,H ¼ 8.6, 2H, C6H4), 6.75 (d,
3JH,H ¼ 8.6, 2H, C6H4), 3.90 (d, JH,P ¼ 4.4, 4H, NCH2P), 1.35 (m, 6H,
2
3
SiCH2CH2CH2Si), 0.89 (t, JH,H ¼ 7.9, 9H, CH2CH3), 0.77 (m, 6H,
SiCH2CH2CH2SiEt), 0.56 (m, 6H, SiCH2CH2CH2SiEt), 0.44 (q,
3JH,H ¼ 7.9, 6H, CH2CH3), ꢁ0.08 ppm (s, 18H, SiCH3). 13C{1H} NMR
(CDCl3, 300 MHz):
d
¼ 7.29 (m, 20H, PC6H5), 7.22 (d, 3JH,H ¼ 8.6, 2H,
(C6D6, 75 MHz):
d
¼ 148.1 (C6H4N, Cipso), 137.4 (d, JC,P ¼ 14.2, PC6H5,
C6H4), 6.75 (d, 3JH,H ¼ 8.6, 2H, C6H4), 3.89 (d, 2JH,P ¼ 4.0, 4H, NCH2P),

96
S. Vigo et al. / Journal of Organometallic Chemistry 717 (2012) 88e98
3
2.61 (m, 6H, SCH2CH2N), 2.53 (m, 6H, SCH2CH2N), 2.26 (s, 18H,
N(CH3)2), 1.78 (s, 6H, SiCH2S), 1.36 (m, 6H, SiCH2CH2CH2Si), 0.78 (m,
6H, C6H4SiCH2CH2CH2Si), 0.66 (m, 6H, C6H4SiCH2CH2CH2Si),
7.45 (m, 12H, PC6H5), 7.26 (d, JH,H ¼ 8.8, 2H, C6H4), 6.63 (d,
3JH,H ¼ 8.8, 2H, C6H4), 3.94 (br., 4H, NCH2P), 1.26 (m, 12H,
3
SiCH2CH2CH2Si), 0.87 (t, JH,H ¼ 8.0, 12H, CH2CH3), 0.72 (m, 4H,
0.05 ppm (s, 18H, SiCH3). 13C{1H} NMR (CDCl3, 75 MHz):
d
¼ 148.1
C6H4SiCH2CH2CH2Si), 0.49 (m, 20H, SiCH2CH2CH2SiCH2CH2CH2Si),
3
(C6H4N, Cipso), 137.1 (d, JC,P ¼ 14.7, PC6H5, Cipso), 134.7 (C6H4Si, Cor-
tho), 133.0 (d, JC,P ¼ 19.1, PC6H5, Cortho), 123.5 (C6H4Si, Cipso), 128.4 (d,
JC,P ¼ 29.5, PC6H5, Cmeta), 128.3 (d, JC,P ¼ 5.9, PC6H5, Cpara), 113.3
(C6H4N, Cortho), 58.7 (SCH2CH2N), 53.3 (br., NCH2P), 45.2 (NCH3),
33.9 (SCH2CH2N), 18.2 (SiCH2S), 19.7, 17.6 and 17.4
(SiCH2CH2CH2Si), ꢁ3.4 ppm (SiCH3). 31P{1H} NMR (CDCl3,
0.42 (q, JH,H ¼ 8.0, 8H, CH2CH3), 0.16 (s, 3H, C6H4SiCH3), ꢁ0.11 (s,
24 H, Si(CH3)2), ꢁ0.15 ppm (s, 6H, SiCH3). 13C{1H} NMR (CDCl3,
75 MHz):
d
¼ 151.8 (C6H4N, Cipso), 135.3 (C6H4Si, Cortho), 133.9 (d,
JC,P ¼ 9.9, PC6H5, Cortho), 131.8 (s, PC6H5, Cpara), 128.8 (d, JC,P ¼ 11.2,
PC6H5, Cmeta), 127.9 (d, JC,P ¼ 57.6, PC6H5, Cipso), 118.1 (C6H4N, Cortho),
53.7 (d, JC,P ¼ 47.1, NCH2P), 19.7, 18.7 and 18.4 (SiCH2CH2CH2Si), 19.1,
18.9 and 18.4 (C6H4SiCH2CH2CH2Si), 7.4 and 7.0 (CH2CH3), ꢁ3.8
(Si(CH3)2), ꢁ4.9 ppm (C6H4SiCH3 and SiCH3 overlapped). 31P{1H}
202 MHz):
(SiCH3), ꢁ5.0 ppm (SiC6H4).
d
¼ ꢁ26.4 ppm. 1He29Si gHMBC (CDCl3):
d
¼ 1.6
NMR (CDCl3, 202 MHz):
d
¼ 10.0 ppm. 1He29Si gHMBC (CDCl3):
4.3.13. [PdCl2{(Ph2PCH2)2N(C6H4-4-SiMe(CH2CH2CH2SiEtMe2)2)}]
([PdCl2(PP:G1:(Et)2)])
d
¼ 2.9 (SiEt), 1.0 (SiMe), ꢁ3.8 ppm (SiC6H4).
A solution of [PdCl2(cod)] (0.220 g, 0.76 mmol) in CH2Cl2 (10 mL)
was added to a solution of PP:G1:(Et)2 (0.600 g, 0.76 mmol) in
CH2Cl2 (15 mL). After stirring for 3 h at room temperature, the
orange solution was evaporated under vacuum and the residue
extracted with hexane (2 ꢃ 10 mL). Volatiles were removed under
vacuum to leave [PdCl2(PP:G1:(Et)2)] as a yellow solid (0.17 g, 82%).
Anal. Calc. for C47H65Cl2NP2PdSi3: C, 58.34; H, 6.77; N, 1.45. Found:
4.3.16. [PdCl2{(Ph2PCH2)2N(C6H4-4-Si(CH2CH2CH2SiMe2(CH2SCH2-
CH2NMe2))3)}] ([PdCl2(PP:G1:(NMe2)3)])
A solution of [PdCl2(cod)] (0.100 g, 0.36 mmol) in CH2Cl2 (5 mL)
was added to a solution of phosphane PP:G1:(NMe2)3 (0.420 g,
0.36 mmol) in CH2Cl2 (10 mL). The reaction mixture was stirred
overnight at room temperature and then the solvent was evapo-
rated under vacuum to afford [PdCl2(PP:G1:(NMe2)3)] as a yellow
solid (0.47 g, 96%) after washing with hexane (3 ꢃ 10 mL). Anal.
Calc. for C63H102Cl2N4P2PdS3Si4: C, 55.50; H, 7.54; N, 4.11; S, 7.06.
Found: C, 55.46; H, 7.62; N, 4.07; S, 6.97%. 1H NMR (CDCl3,
C, 58.34; H, 6.28; N, 1.63%. 1H NMR (CDCl3, 300 MHz):
d
¼ 7.85 (m,
8H, PC6H5), 7.44 (m, 12H, PC6H5), 7.28 (d, 3JH,H ¼ 8.2, 2H, C6H4), 6.62
3
(d, JH,H ¼ 8.2, 2H, C6H4), 3.95 (br., 4H, NCH2P), 1.27 (m, 4H,
3
SiCH2CH2CH2Si), 0.85 (t, JH,H ¼ 7.9, 6H, CH2CH3), 0.73 (m, 4H,
300 MHz):
d
¼ 7.85 (m, 8H, PC6H5), 7.45 (m, 12H, PC6H5), 7.25 (d,
3
C6H4SiCH2CH2CH2Si), 0.50 (m, 4H, C6H4SiCH2CH2CH2Si), 0.39 (q,
3JH,H ¼ 7.9, 4H, CH2CH3), 0.16 (s, 3H, C6H4SiCH3), ꢁ0.12 ppm (s, 12 H,
3JH,H ¼ 8.1, 2H, C6H4), 6.61 (d, JH,H ¼ 8.1, 2H, C6H4), 3.99 (br., 4H,
NCH2P), 2.58 (m, 6H, SCH2CH2N), 2.49 (m, 6H, SCH2CH2N), 2.30 (s,
18H, N(CH3)2), 1.76 (s, 6H, SiCH2S), 1.30 (m, 6H, SiCH2CH2CH2Si),
0.76 (m, 6H, C6H4SiCH2CH2CH2Si), 0.63 (m, 6H, C6H4-
SiCH2CH2CH2Si), 0.01 ppm (s, 18H, SiCH3). 13C{1H} NMR (CDCl3,
Si(CH3)2). 13C{1H} NMR (CDCl3, 75 MHz):
d
¼ 151.7 (C6H4N, Cipso),
135.3 (C6H4Si, Cortho), 133.8 (d, JC,P ¼ 9.9, PC6H5, Cortho), 131.8 (s,
PC6H5, Cpara), 128.8 (d, JC,P ¼ 12.8, PC6H5, Cmeta), 127.9 (d, JC,P ¼ 57.1,
PC6H5, Cipso), 129.8 (C6H4Si, Cipso), 118.9 (s, C6H4N, Cortho), 53.7 (d,
JC,P ¼ 47.7, NCH2P), 19.5, 18.9 and 18.3 (SiCH2CH2CH2Si), 7.3 and 7.0
(CH2CH3), ꢁ3.8 (Si(CH3)2), ꢁ4.9 ppm (C6H4SiCH3). 31P{1H} NMR
75 MHz):
d
¼ 152.0 (C6H4N, Cipso), 135.5 (C6H4Si, Cortho), 133.8 (d,
JC,P ¼ 10.3, PC6H5, Cortho), 131.7 (s, PC6H5, Cpara), 128.7 (d, JC,P ¼ 11.2,
PC6H5, Cmeta), 127.9 (d, JC,P ¼ 55.3, PC6H5, Cipso), 117.9 (C6H4N, Cortho),
1
(CDCl3, 202 MHz):
d
¼ 10.9 ppm. 1He29Si gHMBC (CDCl3):
d
¼ 3.6
129.7 (C6H4Si, Cipso), 58.8 (SCH2CH2N), 53.6 (dd, JC,P ¼ 42.2,
(SiCH2CH3), ꢁ3.5 ppm (SiC6H4).
3JC,P ¼ 3.4, NCH2P), 45.3 (N(CH3)2), 34.0 (SCH2CH2N), 18.3 (SiCH2S),
19.8,17.8 and 17.2 (SiCH2CH2CH2Si), ꢁ3.2 ppm (SiCH3). 31P{1H} NMR
4.3.14. [PdCl2{(Ph2PCH2)2N(C6H4-4-Si(CH2CH2CH2SiEtMe2)3)}]
([PdCl2(PP:G1:(Et)3)])
(CDCl3, 202 MHz):
d
¼ 10.8 ppm. 1He29Si gHMBC (CDCl3):
d
¼ 1.7
(SiCH2S), ꢁ4.1 ppm (SiC6H4).
This compound was isolated as an orange solid (0.54 g, 72%)
following the procedure described above for (PP:G1:(Et)2)PdCl2,
starting from PP:G1:(Et)3 (0.630 g, 0.70 mmol) and [PdCl2(cod)]
(0.200 g, 0.70 mmol). Anal. Calc. for C53H79Cl2NP2PdSi4: C, 58.84; H,
7.36; N, 1.29. Found: C, 58.77; H, 6.83; N, 1.45%. 1H NMR (CDCl3,
4.3.17. [PdI2{(Ph2PCH2)2N(C6H4-4-Si(CH2CH2CH2SiMe2(CH2SCH2CH2-
NMe3))3)}]I3 (PdI2(PP:G1:(NMe3I)3))
Methyl iodide (0.34 mL, 0.69 mmol) was added to a solution
of [PdCl2(PP:G1:(NMe2)3)] (0.150 g, 0.12 mmol) in CH2Cl2
(15 mL) with a syringe. The reaction mixture was stirred over-
night at room temperature and the solvent then removed under
vacuum. The residue thus obtained was washed with diethyl
ether (3 ꢃ 10 mL) and dried in vacuo to yield PdI2(PP:G1:(N-
Me3I)3) as an orange solid (0.17 g, 80%). Anal. Calc. for
C66H111I5N4P2PdS3Si4: C, 40.20; H, 5.67; N, 2.84; S, 4.88. Found:
C, 40.04; H, 5.63; N, 2.84; S, 4.95%. 1H NMR ([D6]DMSO,
300 MHz):
d
¼ 7.83 (m, 8H, PC6H5), 7.40 (m, 12H, PC6H5), 7.26 (d,
3JH,H ¼ 8.2, 2H, C6H4), 6.60 (d, JH,H ¼ 8.2, 2H, C6H4), 3.96 (br., 4H,
NCH2P),1.28 (m, 6H, SiCH2CH2CH2Si), 0.86 (t, 3JH,H ¼ 8.0, 9H, CH2CH3),
0.75 (m, 6H, C6H4SiCH2CH2CH2Si), 0.52 (m, 6H, C6H4SiCH2CH2CH2Si),
0.41 (q, 3JH,H ¼ 8.0, 6H, CH2CH3), ꢁ0.12 ppm (s, 18H, SiCH3). 13C{1H}
3
NMR (CDCl3, 75 MHz):
d
¼ 151.6 (C6H4N, Cipso), 135.5 (C6H4Si, Cortho),
133.9 (d, JC,P ¼ 10.3, PC6H5, Cortho), 131.8 (s, PC6H5, Cpara), 129.8
(C6H4Si, Cipso), 128.8 (d, JC,P ¼ 11.1, PC6H5, Cmeta), 127.9 (d, JC,P ¼ 57.6,
PC6H5, Cipso), 118.0 (C6H4N, Cortho), 53.6 (d, JC,P ¼ 47.0, NCH2P), 19.7,
18.4 and 17.3 (SiCH2CH2CH2Si), 7.4 and 7.0 (CH2CH3), ꢁ3.8 ppm
300 MHz):
d
¼ 7.98 (m, 8H, PC6H5), 7.51 (m, 12H, PC6H5), 6.83 (d,
3JH,H ¼ 8.2, 2H, C6H4), 6.33 (d, 3JH,H ¼ 8.2, 2H, C6H4), 4.72 (br., 4H,
NCH2P), 3.50 (m, 6H, SCH2CH2N), 3.05 (s, 27H, N(CH3)3), 2.83 (m,
6H, SCH2CH2N), 1.87 (s, 6H, SiCH2S), 1.23 (m, 6H, SiCH2CH2CH2Si),
0.65 (m, 6H, C6H4SiCH2CH2CH2Si), 0.58 (m, 6H, C6H4Si-
CH2CH2CH2Si), ꢁ0.08 ppm (s, 18H, SiCH3). 13C{1H} NMR ([D6]
(SiCH3). 31P{1H} NMR (CDCl3, 202 MHz):
d
¼ 10.9 ppm. 1He29Si
gHMBC (CDCl3):
d
¼ 2.9 (SiCH3), ꢁ4.1 ppm (SiC6H4).
4.3.15. [PdCl2{(Ph2PCH2)2N(C6H4-4-SiMe((CH2)3SiMe(CH2)3
SiEtMe2)2)}] ([PdCl2(PP:G2:(Et)4)])
DMSO, 75 MHz):
d
¼ 145.2 (C6H4N, Cipso), 134.0 (d, JC,P ¼ 9.3,
PC6H5, Cortho), 133.6 (C6H4Si, Cortho), 130.7 (s, PC6H5, Cpara), 127.6
(d, JC,P 7.3, PC6H5, Cmeta), 114.0 (C6H4N, Cortho), 63.5
Compound [PdCl2(PP:G2:(Et)4)] was isolated as a yellow solid
(0.70 g, 74%) following the procedure described above for
[PdCl2(PP:G1:(Et)2)], starting from PP:G2:(Et)4 (0.83 g, 0.68 mmol)
and [PdCl2(cod)] (0.19 g, 0.68 mmol). Anal. Calc. for
C69H117Cl2NP2PdSi7: C, 59.34; H, 8.44; N, 1.00. Found: C, 58.88; H,
¼
(SCH2CH2N), 51.7 (N(CH3)3, overlapped with NCH2P), 26.7
(SCH2CH2N), 17.3 (SiCH2S), 18.5, 16.2 and 15.8 (SiCH2-
CH2CH2Si), ꢁ3.9 ppm (SiCH3). 31P{1H} NMR ([D6]DMSO,
202 MHz):
(SiCH2S), ꢁ4.7 ppm (SiC6H4).
d
¼ ꢁ10.4 ppm. 1He29Si gHMBC ([D6]DMSO):
d
¼ 1.8
8.98; N, 1.21%. 1H NMR (CDCl3, 300 MHz):
d
¼ 7.84 (m, 8H, PC6H5),

S. Vigo et al. / Journal of Organometallic Chemistry 717 (2012) 88e98
97
Table 2
that instant as the starting time of the reaction. Stirring of the
mixture was maintained and 1 L samples were withdrawn
Selected crystallographic data and structure refinement details for [PdCl2(PP:Br)].
m
periodically and analyzed by GC using naphthalene as internal
standard.
Empirical formula
Formula weight
Color
C32H18BrCl2NP2Pd$CHCl3
2595.22
Yellow
Temperature (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
200(2)
0.71073
Monoclinic
P21
17.281(4)
17.358(4)
18.260(5)
90
102.73(2)
90
5343(2)
6
1.613
2.132
2580
Acknowledgments
We gratefully acknowledge financial support from the DGI-
Ministerio de Ciencia y Tecnología (Project CTQ2008-02918/BQU
and CTQ2011-24096) and Universidad de Alcalá (FPI grant to SV).
b (Å)
c (Å)
a
b
g
(ꢀ)
(ꢀ)
(ꢀ)
Appendix A. Supplementary material
Volume (Å3)
CCDC 874139 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
Z
Calculated density (g/cm3)
Absorption coefficient (mmꢁ1
F(000)
)
Crystal size (mm)
0.5 ꢃ 0.4 ꢃ 0.3
q
range (ꢀ)
3.05 to 27.57
References
Limiting indices
ꢁ22 ꢄ h ꢄ 21, ꢁ22 ꢄ k ꢄ 22, 0 ꢄ l ꢄ 23
24,508/24,147 [R(int) ¼ 0.0419]
99.5%
Reflections collected/unique
Completeness to qmax
Absorption correction
Max. and min. transmission
Refinement method
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