Synthesis and characterization of water-soluble ferrocene-dendrimers

Article abstract of DOI:10.1016/j.jorganchem.2012.07.048

The synthesis of two new families of water-soluble phosphorus dendrimers of type Poly(PhosphorHydrazone) (PPH) incorporating ferrocene(s) in their internal structure is reported. In the first series, the ferrocene is located at the core and the dendrimers (first and second generations) are ended either by ammonium groups or carboxylate groups, both ensuring the solubility in water. The electrochemical properties of one of them are reported. A new difunctional ferrocene suitable to be used as component of the branches of dendrimers has been synthesized and characterized by X-ray diffraction. It has been used for the synthesis of a second series of dendrimers incorporating 24 ferrocenes, located in the branches at the level of the second generation. The synthesis of these dendrimers is carried out up to the third generation ended by ammoniums or carboxylates.

Full text of DOI:10.1016/j.jorganchem.2012.07.048

Journal of Organometallic Chemistry 718 (2012) 22e30
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis and characterization of water-soluble ferrocene-dendrimers
,
b
,
,
b
,
a
,
,b
Edwin R. de Jong a c, Eric Manoury a
, Jean-Claude Daran b, Cédric-Olivier Turrin a
,
**
Jérôme Chiffre a b, Alix Sournia-Saquet a b, Wolfgang Knoll d, Jean-Pierre Majoral a
,
,
,
,b,
*
Anne-Marie Caminade a
,b,
*
a CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP 44099, F-31077 Toulouse, Cedex 4, France
b Université de Toulouse, UPS, INPT, LCC, F-31077 Toulouse, France
c Max-Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
d Austrian Institute of Technology, Donau-City-Straße 1, 1220 Vienna, Austria
a r t i c l e i n f o
a b s t r a c t
Article history:
The synthesis of two new families of water-soluble phosphorus dendrimers of type Poly(-
PhosphorHydrazone) (PPH) incorporating ferrocene(s) in their internal structure is reported. In the first
series, the ferrocene is located at the core and the dendrimers (first and second generations) are ended
either by ammonium groups or carboxylate groups, both ensuring the solubility in water. The electro-
chemical properties of one of them are reported. A new difunctional ferrocene suitable to be used as
component of the branches of dendrimers has been synthesized and characterized by X-ray diffraction. It
has been used for the synthesis of a second series of dendrimers incorporating 24 ferrocenes, located in
the branches at the level of the second generation. The synthesis of these dendrimers is carried out up to
the third generation ended by ammoniums or carboxylates.
Received 1 June 2012
Received in revised form
26 July 2012
Accepted 31 July 2012
Keywords:
Dendrimers
Ferrocene
Hydrosolubility
Polyammonium
Polycarboxylate
X-ray diffraction
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
to an hydrophilic interior generally based on Poly(PropylenImine)
(PPI) dendrimers [11].
Ferrocene-containing dendrimers have attracted a great interest
since a long time [1], mainly due to their particular electrochemical
properties. Indeed, ferrocene derivatives undergo fast one-electron
oxidation to the ferrocenium form, which is positively charged;
such oxidation is frequently fully reversible. These properties,
combined with those of dendrimers [2], have led to various uses, for
instance as redox sensors for molecular recognition [3], or as
mediators in amperometric biosensors [4], or as electron reservoir
[5], and also as catalysts [6,7]. Most of these properties are studied
in organic solvents; only few water-soluble dendrimeric ferrocenes
have been already described. They include in particular one ferro-
cene at the core of the dendrimer ended by carbohydrate [8] or by
carboxylic acids [9,10]. In other cases, the solubility in water is due
In this paper, we report new water-soluble ferrocene-den-
drimers based on Poly(PhosphorHydrazone) (PPH) dendrimers
[12], in which the ferrocene group(s) is(are) either located at the
core, or at one layer of the internal structure, whereas the solubility
in water is afforded either by ammoniums, or carboxylates as
terminal groups [13].
2. Results and discussion
2.1. Ferrocene as core of water-soluble phosphorus dendrimers
We have already published the synthesis of dendrimers having
a ferrocene as core, based either on the reactivity of ferrocene
bis(diphenylphosphine) with azides [14], or of ferrocene dicarbal-
dehyde with phosphorhydrazide [15]. The P]NeP]S linkages
generated in the first case are poorly stable when left in water for
several days, whereas the phosphorhydrazones generated in the
second case are stable; thus, we chose as core the ferrocene
dicarbaldehyde. The resulting dendrimers have either P(S)Cl2 (1-
Gn) or aldehyde ð1 ꢀ G0nÞ terminal groups, thus they are soluble in
organic solvents, but not in water. However, we have already
demonstrated the use of both types of functional groups to obtain
* Corresponding author. CNRS, LCC (Laboratoire de Chimie de Coordination), 205
route de Narbonne, BP 44099, F-31077 Toulouse, Cedex 4, France. Tel.: þ33 5 61 33
31 25; fax: þ33 5 61 55 30 03.
** Corresponding author. CNRS, LCC (Laboratoire de Chimie de Coordination), 205
route de Narbonne, BP 44099, F-31077 Toulouse, Cedex 4, France.
E-mail addresses: manoury@lcc-toulouse.fr (E. Manoury), majoral@lcc-
toulouse.fr (J.-P. Majoral), caminade@lcc-toulouse.fr (A.-M. Caminade).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.07.048

E.R. de Jong et al. / Journal of Organometallic Chemistry 718 (2012) 22e30
23
water-soluble
dendrimers,
either
by
reacting
N,N-
here the synthesis of a new ferrocene derivative in which the
phenol group is linked to the Cp ring via a CH2 linkage, to ensure
a greater flexibility.
diethylethylenediamine with P(S)Cl2 terminal groups to afford
ammonium end groups [16], or by reacting malonic acid with
aldehyde terminal groups, to afford carboxylate end groups after
reaction with NaOH [17]. Here we have applied both reactions to
generation 1 (1-G1, 1 ꢀ G10 ) and generation 2 (1-G2, 1 ꢀ G02) of the
dendrimers built from ferrocene dicarbaldehyde as core. Such
reactions afford dendrimers bearing charged terminal functions 2-
Gþ1 (4 ammoniums), 3-G1L (4 carboxylates), 2-Gþ2 (8 ammoniums),
3-Gꢀ2 (8 carboxylates) respectively, as shown in Scheme 1.
All these dendrimers are water-soluble, but due to the hydro-
phobic character of the internal structure, they are shrunk in water,
and the NMR signals of the internal structure are frequently not
detected inwater, as we have already demonstrated for another type
of water-soluble phosphorus dendrimer [18]. Thus the character-
ization bymultinucleusNMR wasdone in methanolin the case of the
ammonium terminations, and in dimethylsulfoxide in the case of the
carboxylate terminations. The presence of the cyclopentadienyl
rings at the core is detected in all cases in particular by the presence
of two singlets in 1H NMR at 4.3e4.4 ppm and 4.6e4.7 ppm. The
graftingof the amines induces a deshieldingof the signal in 31P NMR,
The synthetic route to the difunctional ferrocene requires five
steps from the commercially available ferrocenecarboxaldehyde 4.
The first step is the stannylation reaction of 4 which was carried out
as published to afford 5 [20] with a selectivity of 95% to the 10
position. The second step is a nucleophilic attack of lithiated bro-
moanisole on the carbonyl, which affords the ferrocene 6. The third
step is the reduction of the alcohol of 6 with BH3,SMe2 [21] or TiCl4/
NaB(CN)H3 [22] to afford the ferrocene 7. The fourth step is the
substitution of the tributylstannyl group with nBuLi/DMF which
leads to ferrocene 8. The fifth and last step has to be carried out
directly afterwards as 8 is not sufficiently stable for long term
storage. This last step is the deprotection of the methoxy group
with BBr3, to afford the desired difunctional ferrocene 9 (Scheme 2)
[23]. The overall yield for the synthesis of 9 is 17% from commer-
cially available ferrocenecarboxaldehyde.
The structure of compound 9 has been confirmed by X-ray
diffraction analysis on single crystals. The molecule displays a Z-like
shape with the two Cp rings being slightly staggered with a twist
angle of 12.8(2)ꢁ (Fig.1). The two Cp rings are nearly parallel to each
other with a centroideFe1ecentroid angle of 178.23(3)ꢁ. The phenyl
ring is exo with respect to the Cp ring to which it is attached and
makes a dihedral angle of 85.57(16)ꢁ with it. The most interesting
feature of the structure is the occurrence of the OeH.O hydrogen
on going from the P(S)Cl2 terminations (
(NHR)2 terminations (
¼ 69e70 ppm). The grafting of the carbox-
ylate is mainly demonstrated by the disappearance of the aldehyde
d
¼ 62e63 ppm) to the P(S)
d
signal in 1H NMR (
d
¼ 9.9 ppm) on behalf of the appearance of two
doublets (3JHH ¼ 15.9 Hz) corresponding to the AB system generated
by the AreHC]CHeCO2H linkage.
ꢀ
ꢀ
ꢀ
bond [OeH ¼ 0.82 A, H.O ¼ 1.89 A, O.O ¼ 2.698(4) A and Oe
H.O ¼ 171.3ꢁ] between the hydroxyl O atom and the O atom of
the aldehyde group of the symmetry related molecule (ꢀx þ 1/2,
y þ 1/2, ꢀz þ 1/2). These hydrogen bonds build up a zigzag-like chain
developing parallel to the b axis (Fig. 2).
2.2. Ferrocenes in the branches of water-soluble dendrimers
2.2.1. Synthesis of the difunctional ferrocene building block
One of the main building blocks when synthesizing phosphorus
dendrimers is hydroxybenzaldehyde. Thus the easiest way to
incorporate a precise function (such as a ferrocene) in the branches
of these dendrimers consists in synthesizing an analog of hydrox-
ybenzaldehyde, it means a compound having both a phenol and an
aldehyde. We have already used a chiral ferrocene possessing both
functions for studying the influence of the branches on the chirality,
depending on the location of the ferrocene [19], and also a phenol
directly linked to the cyclopentadienyl (Cp) ring [15]. We report
2.2.2. Ferrocenes in the branches of dendrimers
Despite the relatively low yield of the ferrocene 9, the sodium
salt of this compound was used for the grafting on the surface of
a second generation dendrimer having P(S)Cl2 terminations and
built from cyclotriphosphazene as core (10-G2) [24]. A small excess
of ferrocene derivative was used, which was removed and recycled.
The resulting dendrimer ended by ferrocene carbaldehyde 11 ꢀ G20
was isolated in 74% yield after work-up. This dendrimer, as well as
Scheme 1. Synthesis of water-soluble dendrimers having a ferrocene as core.

24
E.R. de Jong et al. / Journal of Organometallic Chemistry 718 (2012) 22e30
Scheme 2. Synthesis of a difunctional ferrocene.
all the following ones, has 24 ferrocenes in its structure. In order to
graft the same type of terminal groups to this dendrimer than in the
case of the dendrimers having ferrocene as core, we needed first to
have P(S)Cl2, then hydroxybenzaldehyde as terminal groups. Thus,
the next step consisted in reacting H2NNMeP(S)Cl2 for the
condensation with the aldehydes of 11 ꢀ G02, to afford the den-
drimer 11-G3, ended by P(S)Cl2 functions. Hydroxybenzaldehyde
was then reacted in the presence of Cs2CO3, to afford dendrimer
11 ꢀ G03. Dendrimer 11-G3 was also used for the reaction with N,N-
diethylethylenediamine, which afforded the positively charged
dendrimer 12-GD3 . As in the case of the reaction 1-Gn / 2-GDn , the
reaction 11-G3 / 12-GD3 is monitored by 31P NMR, which displays
the deshielding of the signal corresponding to the most external
P(S) groups from 63.0 ppm to 69.5 ppm. Dendrimer 13-GL3 ended
by carboxylate groups was also synthesized as previously, from
dendrimer 11 ꢀ G03, using malonic acid (Scheme 3). Here also, the
obtaining of dendrimer 13-GL3 is confirmed by the disappearance of
Fig. 2. Partial packing view showing the formation of the like zigzag chain through Oe
H.O hydrogen bonds. H atoms not involved in hydrogen bonding have been omitted
for clarity.
the signal corresponding to the aldehydes, on behalf of the
appearance of the system of two doublets due to the AreHC]CHe
CO2H linkage in 1H NMR.
2.3. Preliminary electrochemical studies
We intended to study the dendrimers by Cyclic Voltammetry (CV)
in water containing KCl as supporting electrolyte, but we observed
a massive adsorption of the multicharged dendrimers onto the elec-
trode. We tried to optimize the experiments on the small dendrimer
3-GL1 . Fig. 3A displays the results of CV experiments on Gold, Glassy
Carbon, and Platinumelectrodes. Theapparentlargerresistivityof the
solution observed in the case of the Au electrode is due to an impor-
tant adsorption of3-GL1 ontothiselectrode. Asthe adsorptionislower
on the Pt electrode, the next experiments were all carried out with Pt
electrodes. Cyclic voltammograms of dendrimer 3-GL1 in aqueous
solution (see Fig. 3B) exhibit a single electrochemical process
at þ0.35 V/SCE attributed to ferrocene moiety [25].
Subsequently, the influence of the potential scan rate on the
cyclic voltammograms was studied. The ratio between reduction
peak current and oxidation peak current almost equals unity and
anodic peak potential is independent of the logarithm of the scan
rate; this confirms that the electrochemical oxidation process is
reversible. The anodic peak intensity is correlated with the poten-
tial scanning rate (Fig. 4) by the following relationship (Randlese
Sevcik equation) [26], valid for reversible systems:
rffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
pffiffi
nFD
RT
Ip ¼ ꢀ0:4463nFSC
v
where S is the electrode area (cm2); C is the solute (dendrimer)
concentration (mol cmꢀ3); D is the diffusion coefficient (cm2 sꢀ1); F
Fig. 1. Molecular view of compound 9. Ellipsoids are drawn at the 30% probability
level. H atoms are represented as small spheres of arbitrary radii.

E.R. de Jong et al. / Journal of Organometallic Chemistry 718 (2012) 22e30
25
Scheme 3. Synthesis of water-soluble dendrimers having one layer of ferrocenes in the branches.
is the faraday (96,500 C); n is the number of exchanged electrons; v
is the potential scanning rate (V sꢀ1) and T is the absolute
temperature (K).
The dendrimer displays a linear relationship between peak
current and the square root of the scan rate, which indicates
a diffusion controlled process. In this condition, taking n ¼ 1, we can
deduce the diffusion coefficient [26,27] of 3-GL1 that is found to be
equal to 5.6 ꢂ 10ꢀ7 ꢃ 1 ꢂ 10ꢀ7 cm2
s
ꢀ1. Assuming the dendrimers
adopt a spherical shape, the StokeseEinstein relation provides the
dendrimer radius: D ¼ kBT/6phr, with kB being the Boltzmann
Fig. 3. A) Cyclic voltammograms of the 3-GL1 dendrimer in water with KCl as supporting electrolyte at 0.1 V sꢀ1 at 23 ꢃ 1 ꢁC, on Pt electrode (Pt, r ¼ 0.25 mm) (green line), on Glassy
carbon electrode (GC, r ¼ 0.5 mm) (blue line), on gold electrode (Au, r ¼ 10.12 mm) (red line). B) Cyclic voltammograms of the 3-GL1 dendrimer that bear a ferrocene at the core on Pt
microelectrode (r ¼ 0.25 mm) in water with KCl as supporting electrolyte at different scan rate at 23 ꢃ 1 ꢁC. (For interpretation of color referred in this figure legend, the reader is
referred to web version of the article.)

26
E.R. de Jong et al. / Journal of Organometallic Chemistry 718 (2012) 22e30
as shown by the measurement of the diffusion constant by elec-
trochemistry. This might be related to the percentage of charged
end groups at pH w 6 (more than 90% of charged terminal groups in
the case of carboxylic acids), as measured for other dendrimers
having the same terminal groups than here [28].
4. Experimental
All reactions are carried out under argon atmosphere and in
freshly distilled solvents. All water used is demineralised using
MilliQ equipment and the resistivity was 18 MU cm. All purifica-
tions by column chromatography were carried out with silicagel 60
as the static phase. All starting compounds were purchased from
Aldrich, Merck or Fluka and used as received. Compounds 1-G1,
1 ꢀ G01, 1-G2, 1 ꢀ G20 [15], 5 [20], and 10-G2 [24] were synthesized as
published. 1H, 13C{1H}, 31P{1H} and two-dimensional NMR spectra
were recorded on a Bruker 300 (DPX300) and 200 (AC200) MHz
spectrometers. Chemical shifts are reported in ppm relative to
external standards (TMS for 1H and 13C and 85% H3PO4 for 31P) and
coupling constants are given in Hz. The numbering used for NMR
assignment is shown in Fig. 5. Mass spectrometry experiments did
not afford accurate information about the structure of these den-
drimers, due to fragmentation and rearrangements [29].
Fig. 4. Oxidation peak current of 3-GL1 plotted against the square root of the scan rate
(3-GL1 dendrimer (5 ꢂ 10ꢀ3 mol Lꢀ1) on Pt microelectrode (r ¼ 0.5 mm) in water with
KCl as supporting electrolyte at different scan rates at 23 ꢃ 1 ꢁC).
constant, T the absolute temperature,
h the solution viscosity and r
the dendrimer radius. The diffusion coefficient D in water is
5.6 ꢂ 10ꢀ7 cm2
s
ꢀ1, and the radius deduced from this value is
4.1. Dendrimer 2-G1þ
4 ꢃ 2 nm (expected 2.5 nm).
The electrochemical behavior of the corresponding second
generation dendrimers (2-GD2 and 3-GL2 ) was also studied. In both
cases the oxidation was found not reversible, due to a high
adsorption onto the electrodes, and presumably to the oxidation of
the organic moieties of the dendrimer, inducing a drift of the
current. In the case of dendrimers 12-GD3 and 13-G3L, their solubility
in the conditions used was not high enough to study their elec-
trochemical behavior.
A solution of 600 mg of dendrimer 1-G1 (1.06 mmol, 1.0 eq) in
10 mL THF was cooled to 0 ꢁC and to this 596
mL of N,N-
diethylethylenediamine (4.24 mmol, 4.0 eq) was added dropwise.
The reaction mixture was kept stirring overnight at room temper-
ature. The solvent was evaporated and after two washing steps
with ether, 472 mg (459
tained as an orange powder.
m
mol, 43%) of dendrimer 2-GD1 was ob-
1H NMR (300 MHz, CD3OD): 1.32 (m, 24H, NeCH2eCH3), 3.21 (m,
32H, CH2), 3.35 (d, 3JHP ¼ 10.2 Hz, 6H, P1eNeCH3), 4.36 (s, 4H, Cp),
4.75 (s, 4H, Cp), 7.6 (s, 2H, CH]NeNeP1). 31P{1H} NMR (121.5 MHz,
CDCl3): 69.8 (s, P1). 13C{1H} NMR (75.5 MHz, CD3OD): 8.3 (Ne
CH2CH3), 31.2 (d, 2JCP ¼ 9.9 Hz, P1eNeCH3), 36.6 (CH2eNeP1), 49.2
(NCH2CH3) (CD3OD), 52.6 (d, 3JCP ¼ 6.6 Hz, P1eNeCH2CH2), 68.1 (Cp),
70.5 (Cp), 82.3 (Cpquat), 138.8 (d, 3JCP ¼ 14.1 Hz, CH]NeNeP1).
3. Conclusion
We have used two different types of difunctionalized ferrocenes
for the synthesis of water-soluble Poly(PhosphorHydrazone) (PPH)
dendrimers. The first one (ferrocene dicarbaldehyde) has two
identical functions, and was used as core of the dendrimers. The
second one was especially engineered to have two different func-
tions (phenol and aldehyde) usable to be introduced in the
branches of the dendrimers. All the water-soluble dendrimeric
ferrocenes that we have synthesized possess a hydrophobic interior
and a hydrophilic external layer. We have already demonstrated
that other dendrimers having these properties are shrunk in water
[18]. The consequence here is that it is difficult to perform elec-
trochemical experiments, and only the smaller compound 3-G1L
affords a clean electrochemical response. When the dendrimers are
larger, the ferrocene is buried inside the organic (hydrophobic)
layer and cannot access easily to the electrode. The dendrimer
ended by carboxylates 3-GL1 is practically non-aggregated in water,
4.2. Dendrimer 2-G2þ
To a solution of 720 mg of dendrimer 1-G2 (465
m
mol, 1.0 eq) in
mL of N,N-diethylethylenediamine
20 mL THF was added 523
(3.72 mmol, 8.0 eq) at 0 ꢁC. This solution was kept stirring over-
night at room temperature. The solvent volume was reduced and
the dendrimer was precipitated from ether and washed several
times with ether. A 1.00 g (403
obtained as an orange powder.
m
mol, 87%) of dendrimer 2-GD2 was
1H NMR (300 MHz, CD3OD): 1.31 (m, 48H, NeCH2CH3), 3.26 (d,
3JHP ¼ 7.8 Hz, 18H, P1,2eNeCH3), 3.33 (m, 64H, CH2), 4.41 (s, 4H, Cp),
3
4.70 (s, 4H, Cp), 7.28 (d, JHH ¼ 8.1 Hz, 8H, CHarom), 7.65 (s, 2H,
Fig. 5. Numbering used for NMR assignments.

E.R. de Jong et al. / Journal of Organometallic Chemistry 718 (2012) 22e30
27
CH]NeNeP1), 7.74 (s, 4H, CH]NeNeP2), 7.86 (d, 3JHH ¼ 8.1 Hz, 8H,
CHarom.). 31P{1H} NMR (121.5 MHz, CD3OD): 62.4 (s, P1), 70.2 (s,
P2). 13C{1H} NMR (75.5 MHz, CD3OD): 7.9 (NeCH2CH3), 31.1 (d,
2JCP ¼ 10.0 Hz, P1,2eNeCH3), 36.2 (CH2eNeP2), 49.6 (NeCH2CH3),
DCM and washed several times with distilled water till both phases
were clear. The organic phase was dried over Na2SO4 and evapo-
rated. The crude material was purified by column chromatography
(several percent of ethyl acetate in hexane, increasing to 10%, with
few drops of triethylamine) yielding 1.04 g of compound 6 as an
orange oil (1.70 mmol, 72%).
3
52.2 (d, JCP ¼ 6.9 Hz, P2eNeCH2CH2), 68.5 (Cp), 71.1 (Cp), 81.2
(Cpquat), 121.3 (d, 3JCP-1 ¼ 5.1 Hz, C21), 127.8 (C31), 133.2 (C41), 137.5 (d,
3JCP ¼ 12.5 Hz, CH]NeNeP1), 151.1 (d, 2JCP ¼ 6.9 Hz, C11).
1H NMR (250 MHz, CDCl3): 0.9e1.1 (m, 9H, SnBu3), 1.6e1.1 (m,
18H, SnBu3), 2.51 (d, J ¼ 2.7 Hz, 1H, OH), 3.78 (s, 3H, OMe), 4.09 (m,
1H, Cp), 4.12 (s, 4H, Cp), 4.24 (t, J ¼ 1.6 Hz, 1H, Cp), 4.40 (t, J ¼ 1 Hz,
2H, Cp), 5.45 (d, J ¼ 2.7 Hz, 1H, CHeO), 6.86 (m, 2H, CHarom), 7.31
(m, 2H, CHarom). 13C{1H} NMR (63 MHz, CDCl3): 10.3 (satellites:
two doublets, J119Sne13C ¼ 348 Hz and J117Sne13C ¼ 332 Hz,
SnBu3), 13.9 (SnBu3), 27.5 (satellites: two doublets, J119Sne
13C ¼ 58 Hz and J117Sne13C ¼ 55 Hz, SnBu3), 29.3 (satellites: one
doublet, JSne13C ¼ 20 Hz SnBu3), 55.2 (OCH3), 65.8 (quat Cp), 67.4
(Cp), 68.15 (Cp), 68.19 (Cp), 69.6 (satellites: two doublets, J119Sne
13C ¼ 394 Hz and J117Sne13C ¼ 377 Hz, quat Cp), 71.01 (satellites:
one doublet, JSne13C ¼ 33 Hz, Cp), 70.98 (satellites: one doublet,
4.3. Dendrimer 3-G1ꢀ
A mixture of 486 mg of dendrimer 1 ꢀ G01 (537
m
mol, 1.0 eq),
895 mg of malonic acid (8.6 mmol, 16 eq) and 45
mL of piperidine
(freshly distilled over CaH2) were dissolved in 30 mL pyridine
(freshly distilled over CaH2) and kept under stirring overnight at
95 ꢁC. The reaction mixture was refluxed for 15 min and precipi-
tated with 37% HCl (in the dark). The precipitate was washed
several times with water and ether and subsequently freeze-dried.
The dendrimer was turned into a sodium salt with 9.08 mL of
aqueous NaOH (0.1996 M, 4 eq). This quantitatively yielded 624 mg
of dendrimer 3-GL1 as a dark red powder.
J
Sne13C ¼ 33 Hz, Cp), 71.9 (Cp), 74.92 (satellites: one doublet, JSne
13C ¼ 41 Hz, Cp), 74.95 (satellites: one doublet, JSne13C ¼ 41 Hz,
Cp),94.0 (CHOH), 113.8 (Ph), 127.6 (Ph)), 135.8 (quat Ph), 158.9
(quat Ph). 117Sn{1H} NMR (CDCl3): ꢀ18.5. MS (DCI, NH3): 611 (13%,
M), 595 (100%, MeOH).
3
1H NMR (300 MHz, DMSO-d6): 3.22 (d, JHP ¼ 11.4 Hz, 6H, P1e
3
NeCH3), 4.29 (s, 4H, Cp), 4.55 (s, 4H, Cp), 6.48 (d, JHH ¼ 15.9 Hz,
3
4H, CH]CH), 7.23 (d, JHH ¼ 7.9 Hz, 8H, CHarom.), 7.58 (d,
3JHH
¼
15.9 Hz, 6H, CH]CH and CH]NeNeP1), 7.77 (d,
3JHH ¼ 7.9 Hz, 8H, CHarom.). 31P{1H} NMR (121.5 MHz, DMSO-d6):
61.5 (s, P1). 13C{1H} NMR (75.5 MHz, DMSO-d6): 33.2 (d,
2JCP ¼ 12.3 Hz, P1eNeCH3), 68.8 (Cp), 71.7 (Cp), 81.1 (Cpquat), 119.8
(AreCH]CH), 121.7 (d, 3JCP ¼ 5.1 Hz, C21), 130.3 (C31), 132.1 (C41), 142.2
(CH]NeNeP1), 143.2 (CH]CHeCOOH), 151.8 (d, 2JCP ¼ 6.7 Hz, C11),
167.9 (COO).
4.6. (4-Methoxyphenyl)-(10-tributylstannylferrocenyl)-methane 7
4.6.1. Method A
In a Schlenk tube, a 25 mL THF solution of compound 6
(3.91 mmol, 1.0 eq) was preheated to 90 ꢁC to reflux conditions
before 3.91 mL of a borane dimethylsulfide complex (1.0 M in DCM,
3.91 mmol, 1.0 eq) were added. The mixture was refluxed for
30 min and directly quenched with water. The product was
extracted with pentane and the organic phase was dried over
MgSO4. The product was further purified on column chromatog-
raphy using pentane as eluent. This procedure yielded 1.68 g of
product 7 (2.83 mmol, 73%) as a red oil.
4.4. Dendrimer 3-G2ꢀ
In 50 mL of pyridine (freshly distilled over CaH2) were dissolved
750 mg of dendrimer 1 ꢀ G02 (335
m
mol, 1.0 eq), 558 mg of malonic
acid (5.36 mmol, 16 eq) and 70
mL of piperidine (freshly distilled
over CaH2). This solution was stirred overnight at 95 ꢁC. The
mixture was refluxed for 15 min; the dendrimers were precipitated
from 37% HCl and washed several times with water and ether. The
dendrimers were transformed into their sodium salt analog by
means of ion exchange with 13.5 mL of NaOH (0.1996 M, 2.70 mmol,
4.6.2. Method B
In a Schlenk tube, to 3 mL of THF, at 0 ꢁC, were added 65
ml of
titanium tetrachloride (0.6 mmol, 1 eq) and 189 mg of sodium
cyanoborohydride (3 mmol, 5 eq). The reaction mixture, initially
black, is kept stirring at 0 ꢁC during 30 min to become gradually
a clear yellow solution. To this solution was added a solution of
370 mg of compound 6 in 3 mL THF (0.6 mmol, 1.0 eq). After 5 min
stirring at 0 ꢁC, 50 mL of a 2 N aqueous ammonia solution was
added. The reaction mixture was filtered on Büchner, washed three
times with sodium hydroxide 2 N aqueous solution, then dried over
Na2SO4 and evaporated to yield a yellow oil (370 mg). The product
was further purified on silicagel by flash chromatography using
a pentane/ether mixture (99/1) as eluent. This procedure yielded
0.329 g of product 7 (0.55 mmol, 92%) as a red oil.
8 eq), which yielded 868 mg (338
an orange powder.
m
mol,100%) of dendrimer 3-GL2 as
1H NMR (300 MHz, DMSO-d6): 3.23 (d, JHP ¼ 10.8 Hz, 6H, P1e
3
3
NeCH3), 3.31 (d, JHP ¼ 10.5 Hz, 12H, P2eNeCH3), 4.28 (s, 4H, Cp),
4.58 (s, 4H, Cp), 6.45 (d, 3JHH ¼ 15.9 Hz, 8H, CH]CH), 7.22 (m, 24H,
3
CHarom.), 7.53 (d, JHH ¼ 15.9 Hz, 8H, CH]CH), 7.68 (m, 24H,
CHarom.), 7.93 (s, 6H, CH]NeNeP1,2). 31P{1H} NMR (121.5 MHz,
DMSO-d6): 61.8 (2s, P1,2). 13C{1H} NMR (75.5 MHz, DMSO-d6): 33.2
(d, 2JCP ¼ 12.4 Hz, P1eNeCH3), 33.4 (d, 2JCP ¼ 12.2 Hz, P2eNeCH3),
68.7 (Cp), 71.7 (Cp), 81.2 (Cpquat), 120.0 (C21), 121.8 (d, 3JCP ¼ 3.2 Hz,
C22), 128.8 (C31), 130.3 (C23), 132.2 (C42), 132.4 (C41), 141.3 (d,
3JCP ¼ 16.4 Hz, CH]NeNeP1,2), 143.0 (CH]CHeCOOH), 151.3 (d,
2JCP ¼ 6.6 Hz, C12), 151.6 (d, 2JCP ¼ 4.8 Hz, C11), 168.0 (COO).
1H NMR (250 MHz, CDCl3): 0.9e1.7 (m, 21H, SnBu3), 1.74 (m, 6H,
SnBu3), 3.63 (s, 2H, CH2), 3.77 (s, 3H, OMe), 3.97 (t, J ¼ 1.6 Hz, 2H,
Cp), 4.04e4.00 (s, 4H, Cp), 4.29 (t, J ¼ 1.6 Hz, 1H, Cp), 6.80 (d,
J ¼ 8.6 Hz, 2H, CHarom), 7.09 (d, J ¼ 8.6 Hz, 2H, CHarom). 13C{1H}
NMR (63 MHz, CDCl3): 10.2 (satellites: two doublets, J119Sne
13C ¼ 347 Hz and J117Sne13C ¼ 332 Hz, SnBu3), 13.7 (SnBu3), 27.4
(satellites: one doublets, JSne13C ¼ 57 Hz, SnBu3), 29.2 (satellites:
one doublet, JSne13C ¼ 18.3 Hz SnBu3), 35.3 (CH2), 55.2 (OCH3), 67.5
(Cp), 68.5 (Cp), 68.7 (quat Cp), 71.3 (satellites: one doublet, JSne
4.5. (4-Methoxyphenyl)-(10-tributylstannylferrocenyl)-methanol 6
In a Schlenk tube, a solution of 325
mL of bromoanisole
(2.6 mmol) in 7.5 mL of THF was cooled down to ꢀ64 ꢁC. To this
solution, 1.5 mL of a n-butyl lithium solution (1.6 M in pentane,
2.4 mmol) were slowly added and the mixture was stirred for 1 h at
this temperature. At ꢀ64 ꢁC a 20 mL THF solution containing 1.19 g
of ferrocene 5 (2.36 mmol) was added. This mixture was stirred for
15 min at ꢀ64 ꢁC and was allowed to stir for 2 h at room temper-
ature. The THF was evaporated and the product was dissolved in
13C
¼
34.6 Hz, Cp), 75.0 (satellites: one doublet, JSn-
13C ¼ 42.2 Hz, Cp), 88.1 (quat Cp), 113.3 (Ph), 129.2 (Ph), 133.9 (quat
Ph), 157.8 (quat Ph). 117Sn{1H} NMR (CDCl3): ꢀ18.3. MS (DCI, CH4):
596 (100%, M þ 1).

28
E.R. de Jong et al. / Journal of Organometallic Chemistry 718 (2012) 22e30
4.7. 10-[(4-Methoxyphenyl)methyl]ferrocenecarboxaldehyde 8
4.10. Dendrimer 11-G3
In a Schlenk tube, a 20 mL THF solution of 0.84 g of compound 7
To a solution of 100 mg (8.6
in 8 mL of chloroform were added 0.9 mL of a 0.24 M solution of
m
mol, 1.0 eq) of dendrimer 11 ꢀ G20
(1.41 mmol, 1.0 eq) was cooled to ꢀ78 ꢁC before 791
m
L of a n-butyl
lithium solution (2.5 M in hexane, 1.98 mmol, 1.4 eq) were added.
This mixture was stirred for 15 min at this temperature, and
subsequently for 1 h at room temperature. Then it was cooled again
H2NNMePSCl2 (265
precipitated from pentane twice. A 128 mg (8.3
m
mol, 25 eq). After 45 min the product was
mol, 96%) of
m
dendrimer 11-G3 were obtained as an orange powder.
to ꢀ78 ꢁC and 593
mL
of freshly distilled (on CaH2) DMF
1H NMR (300 MHz, CDCl3): 3.23 (s, 48H, CH2Fc), 3.35 (d,
3JHP ¼ 15 Hz, 72H, CH3NeP3), 3.51 (m, 54H, CH3NeP1,2), 4.05 (2s,
96H, Cp), 4.31 (s, 48H, Cp), 4.59 (s, 48H, Cp), 6.95e7.62 (m, 212H,
CHarom. þ CH]N). 31P{1H} NMR (121.5 MHz, CDCl3): 8.6 (s, P0),
62.3 (s, P1,2), 63.0 (s, P3). 13C{1H} NMR (75.5 MHz, CDCl3): 32.1 (d,
(7.045 mmol, 5.5 eq) was added. This mixture was stirred at this
temperature for 15 min and then stirred at room temperature
overnight. The reaction was quenched by the addition of water
followed by extraction with ether, washing with brine and drying
on Na2SO4. After column purification (up to 30% ether in hexane)
the product 8 was yielded as 0.363 g (1.09 mmol, 77%) of a red oil.
1H NMR (250 MHz, CDCl3): 3.52 (s, 2H, CH2), 3.76 (s, 3H, OMe),
4.18 (m, 4H, Cp), 4.55 (t, J ¼ 1.9 Hz, 2H, Cp), 4.73 (t, J ¼ 1.9 Hz, 2H,
Cp), 6.79 (m, 2H, CHarom), 7.05 (m, 2H, CHarom), 9.90 (s, 1H, CHO).
13C{1H} NMR (63 MHz, CDCl3): 34.4 (CH2), 55.2 (OCH3), 69.2 (Cp),
70.1 (Cp), 70.2 (Cp), 74.0 (Cp), 79.6 (quat Cp), 90.6 (quat Cp), 113.8
(Ph), 129.2 (Ph), 133.0 (quat Ph), 158.0 (quat Ph), 193.5 (CHO). MS
(DCI, NH3): 335 (100%, M þ 1).
2JCP ¼ 12.5 Hz, CH3eNeP3), 33.1 (d, JCP ¼ 12.6 Hz, CH3eNeP0,1),
2
34.9 (CH2), 68.7 (Cp), 69.0 (Cp), 70.1 (Cp), 71.0 (Cp), 79.0 (Cpquat),
88.6 (Cpquat), 121.2 (d, JCP-2 ¼ 4.5 Hz, C22), 121.8 (C20,1), 128.3 (C30,1),
3
129.3 (C32), 132.2 (C04), 132.4 (C41), 138.5 (C42), 143.6 (d,
3JCP1,2,3 ¼ 18.9 Hz, CH]NeNeP1,2,3), 148.8 (d, JCP2 ¼ 6.8 Hz, C12),
2
151.2 (d, 2JCP-0,1 ¼ 6.0 Hz, C10,1).
4.11. Dendrimer 11 ꢀ G30
A solution of 71 mg of dendrimer 11-G3 (4.59
27.8 mg of p-hydroxybenzaldehyde (228 mol, 50 eq) and 149 mg
of Cs2CO3 (457 mol,100 eq) in 5 mL of THF was stirred overnight at
mmol, 1.0 eq),
m
4.8. 10-[(4-Hydroxyphenyl)methyl]ferrocenecarboxaldehyde 9
m
room temperature. The product was precipitated from pentane
In a Schlenk tube, a 6 mL DCM solution of 207 mg of compound
yielding 91 mg (4.65
orange powder.
m
mol, 100%) of dendrimer 11 ꢀ G03 as an
8 (622
m
mol, 1.0 eq) was cooled to ꢀ78 ꢁC and 2.2 mL of boron
tribromide (1.0 M in DCM, 2.2 mmol, 3.5 eq) were added. The
reaction was stirred at room temperature and in the dark for
45 min. The reaction mixture was added to vigorously stirred ice
water and stirred for 15 min. The product was extracted with DCM,
washed three times with an aqueous 1.0 M Na2S2O3 solution, three
times with brine and finally dried over Na2SO4. After column
chromatography (30% ether in pentane) the product 9 was yielded
1H NMR (300 MHz, CDCl3): 3.24e3.32 (2s þ d, JHP ¼ 15 Hz,
48H þ 72H, CH2Fc þ CH3NeP3), 3.41 (m, 54H, CH3NeP1,2), 3.95 (s,
96H, Cp), 4.26 (s, 48H, Cp), 4.52 (s, 48H, Cp), 6.95e7.82 (m, 402H,
CHarom. þ CH]N), 9.86 (s, 48H, CHO). 31P{1H} NMR (121.5 MHz,
CDCl3): 8.36 (s, P0), 59.9 (s, P3), 62.5 (s, P1), 63.0 (s, P2). 13C{1H} NMR
(75.4 MHz, CDCl3): 32.9 (d, 2JCP ¼ 13.5 Hz, CH3NeP1,2,3), 34.8 (CH2),
68.3 (Cp), 68.9 (Cp) 69.9 (Cp), 70.8 (Cp), 79.7 (Cpquat), 88.3 (Cpquat),
121.2 (d, 3JCP-0,1,2 ¼ 4.2 Hz, C02,1,2), 121.8 (d, 3JCP-3 ¼ 5.1 Hz, C23), 128.3
(C30,1), 129.3 (C23), 131.4 (C33), 132.2 (C04), 132.5 (C34), 133.5 (C44), 138.4
3
as a red powder (143 mg, 447 mmol, 72%). Monocrystals of 9 suit-
able for X-ray diffraction analysis have been obtained by slow
diffusion of hexane in a dichloromethane solution of 9.
1H NMR (250 MHz, CDCl3): 3.51 (s, 2H, CH2), 4.18 (m, 4H, Cp),
4.55 (t, J ¼ 1.9 Hz, 2H, Cp), 4.73 (t, J ¼ 1.9 Hz, 2H, Cp), 6.72 (d,
J ¼ 8.5 Hz, 2H, CHarom), 6.99 (d, J ¼ 8.5 Hz, 2H, CHarom), 9.90 (s,1H,
CHO). 13C{1H} NMR (63 MHz, CDCl3): 34.4 (CH2), 69.1 (Cp), 70.1
(Cp), 70.2 (Cp), 73.8 (Cp), 80.5 (quat Cp), 91.2 (quat Cp), 115.2 (Ph),
129.5 (Ph), 132.4 (quat Ph), 155.9 (quat Ph), 193.5 (CHO). MS (DCI,
NH3): 321 (100%, M þ 1).
(C42), 141.4 (d, JCP-1,2,3 ¼ 13.5 Hz, CH]NeNeP1,2,3), 148.8 (d, JCP-
3
2
¼ 6.9 Hz, C12), 151.2 (C10,1), 155.2 (d, 2JCP-3 ¼ 6.7 Hz, C13), 190.7 (CHO).
2
4.12. Dendrimer 12-G3þ
To a 5 mL THF solution of 47 mg of dendrimer 11-G3 (3.69
1.0 eq) were added 25.4 of N,N-diethylethylenediamine
(177
mol, 48 eq) at 0 ꢁC. It was washed twice with dry THF
mmol,
m
L
m
(partly soluble). 37 mg (1.76
obtained as an orange solid.
m
mol, 48%) of dendrimer 12-GD3 were
4.9. Dendrimer 11 ꢀ G20
1H NMR (300 MHz, CD3OD): 1.23 (m, 24H, NeCH2eCH3), 3.21
3
To a suspension of 5.1 mg of NaH (215
m
mol, 27 eq) in 5 mL of
mol, 28 eq) in 5 mL
(m, 32H, CH2), 3.23 (2s, 48H, CH2Fc), 3.35 (d, JHP ¼ 15 Hz, 72H,
THF, a solution of 71.5 mg of compound 9 (223
m
CH3NeP3), 3.51 (m, 54H, CH3NeP1,2), 4.02 (2s, 96H, Cp), 4.21 (s,
48H, Cp), 4.58 (s, 48H, Cp), 6.98e7.63 (m, 212H, CHarom. þ CH]N).
31P{1H} NMR (121.5 MHz, CD3OD): 8.6 (s, P0), 61.3 (s, P1), 62.7 (s, P2),
69.5 (s, P3). 13C{1H} NMR (75.5 MHz, CD3OD): 9.0 (CH3CH2eN), 32.1
THF was added at 0 ꢁC. This mixture was stirred for 1 h at room
temperature. Subsequently it was cooled again to 0 ꢁC and a 5 ml
THF solution of 10-G2 (7.69 mmol, 1.0 eq) was added. The reaction
2
2
was stirred overnight at room temperature. The solution volume
was reduced and the dendrimer was precipitated from ether/
(d, JCP ¼ 12.5 Hz, CH3NeP3), 33.1 (d, JCP ¼ 12.6 Hz, CH3eNeP1,2),
34.9 (CH2), 36.3 (CH2eNeP3), 49.6 (CH3CH2eN), 52.2 (d,
3JCP ¼ 6.9 Hz, CH2CH2eNeP3), 68.7 (Cp), 69.0 (Cp), 70.1 (Cp), 71.0
(Cp), 79.0 (Cpquat), 87.6 (s, Cpquat), 121.2 (d, 3JCP-2 ¼ 4.5 Hz, C22), 121.8
(C20,1), 128.3 (C30,1), 129.3 (C23), 132.2 (C04), 132.4 (C41), 138.5 (C42), 143.6
(d, 3JCP-1,2,3 ¼ 18.9 Hz, CH]NeNeP1,2,3),148.8 (d, 2JCP-2 ¼ 6.8 Hz, C12),
151.2 (d, 2JCP-0,1 ¼ 6.0 Hz, C10,1).
pentane (1:3). A 66 mg (5.69
obtained as an orange powder.
m
mol, 74%) of dendrimer 11 ꢀ G02 were
1H NMR (300 MHz, CDCl3): 3.22 (m, 54H, P1,2eNeCH3), 3.49 (s,
48H, CH2Fc), 4.13 (s, 96H, Cp), 4.49 (s, 48H, Cp), 4.68 (s, 48H, Cp),
6.92e7.61 (m, 186H, CHarom þ CH]N), 9.86 (s, 24H, CHO). 31P{1H}
NMR (121.5 MHz, CDCl3): 8.4 (s, P0), 62.6 (s, P1), 62.9 (s, P2). 13C{1H}
NMR (75.5 MHz, CDCl3): 33.1 (d, 2JCP ¼ 12.3 Hz, CH3eNeP1,2), 34.6
(CH2), 69.4 (Cp), 70.2 (Cp), 70.3 (Cp), 74.0 (Cp), 79.6 (Cpquat), 89.5
(Cpquat), 121.2 (d, 3JCP-2 ¼ 4.5 Hz, C22), 121.8 (C20,1), 128.3 (C30,1), 129.3
(C32), 132.2 (C04), 132.4 (C41), 138.1 (C42), 138.6 (m, CH]NeNeP1,2),
148.9 (d, 2JCP-2 ¼ 7.1 Hz, C12), 151.2 (C10,1), 193.4 (CHO).
4.13. Dendrimer 13 ꢀ G3ꢀ
In 2 mL of freshly distilled (on CaH2) pyridine were dissolved
60 mg of dendrimer 11 ꢀ G03 (3.07
mmol, 1.0 eq), 32 mg of malonic
acid (307 mmol, 100 eq) and 1.5 mL of piperidine (freshly distilled

E.R. de Jong et al. / Journal of Organometallic Chemistry 718 (2012) 22e30
29
Table 1
Table 2
ꢁ
ꢀ
Crystal data and structure refinement for compound 9.
Bond lengths [A] and angles [ ] for compound 9.
Identification code
Empirical formula
Formula weight
Temperature
Wavelength
Crystal system
Space group
9
C
Fe(1)eCT1
O(1)eC(114)
O(2)eC(21)
C(1)eC(5)
C(1)eC(2)
C(1)eC(11)
C(2)eC(3)
C(3)eC(4)
C(4)eC(5)
1.6480(4)
1.365(3)
1.218(5)
1.412(4)
1.417(4)
1.495(4)
1.404(4)
1.399(5)
1.423(4)
1.410(5)
1.428(4)
1.441(5)
178.23(3)
106.7(3)
127.1(3)
126.2(3)
108.9(3)
108.3(3)
107.6(3)
108.5(3)
107.8(3)
126.0(3)
125.4(3)
107.9(3)
108.6(3)
108.7(3)
Fe(1)eCT2
C(7)eC(8)
C(8)eC(9)
C(9)eC(10)
C(11)eC(111)
C(111)eC(116)
C(111)eC(112)
C(112)eC(113)
C(113)eC(114)
C(114)eC(115)
C(115)eC(116)
1.6432(4)
18H16FeO2
1.390(5)
1.401(5)
1.399(5)
1.521(3)
1.376(4)
1.380(4)
1.370(4)
1.380(4)
1.382(4)
1.385(4)
320.16
293(2) K
0.71073 A
Monoclinic
P21/n
ꢀ
¼ 90ꢁ
ꢀ
a
Unit cell dimensions
a ¼ 7.5652(10) A
b ¼ 11.0984(11) A
b
¼ 92.875(16)ꢁ
ꢀ
¼ 90ꢁ
C(6)eC(7)
C(6)eC(10)
C(6)eC(21)
ꢀ
c ¼ 17.134(2) A
g
3
ꢀ
Volume
Z
Density (calculated)
Absorption coefficient
F(000)
Crystal size
Theta range for data collection
Index ranges
Reflections collected
Independent reflections
Completeness to theta ¼ 26.06ꢁ
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I > 2sigma(I)]
R indices (all data)
Largest diff. peak and hole
1436.8(3) A
4
1.480 Mg/m3
1.050 mmꢀ1
664
CT2eFe(1)eCT1
C(5)eC(1)eC(2)
C(5)eC(1)eC(11)
C(2)eC(1)eC(11)
C(3)eC(2)eC(1)
C(4)eC(3)eC(2)
C(3)eC(4)eC(5)
C(1)eC(5)eC(4)
C(7)eC(6)eC(10)
C(7)eC(6)eC(21)
C(10)eC(6)eC(21)
C(8)eC(7)eC(6)
C(7)eC(8)eC(9)
C(10)eC(9)eC(8)
C(9)eC(10)eC(6)
C(1)eC(11)eC(111)
O(2)eC(21)eC(6)
106.9(3)
114.6(2)
123.9(4)
117.9(2)
122.1(3)
120.0(3)
121.8(3)
120.0(3)
117.4(3)
123.3(3)
119.3(3)
119.8(3)
121.3(3)
0.64 ꢂ 0.45 ꢂ 0.1 mm3
C(116)eC(111)eC(112)
C(116)eC(111)eC(11)
C(112)eC(111)eC(11)
C(113)eC(112)eC(111)
C(112)eC(113)eC(114)
O(1)eC(114)eC(113)
O(1)eC(114)eC(115)
C(113)eC(114)eC(115)
C(114)eC(115)eC(116)
C(111)eC(116)eC(115)
2.19e26.06ꢁ
ꢀ9 ꢄ h ꢄ 9, ꢀ13 ꢄ k ꢄ 13, ꢀ21 ꢄ l ꢄ 21
10,984
2804 [R(int) ¼ 0.0702]
98.6%
Full-matrix least-squares on F2
2804/0/191
0.832
R1 ¼ 0.0367, wR2 ¼ 0.0720
R1 ¼ 0.0706, wR2 ¼ 0.0788
ꢀꢀ3
0.390 and ꢀ0.333 e.A
The structure was solved by direct methods (SIR97 [30]) and
over CaH2) and stirred overnight at 95 ꢁC. The reaction mixture was
refluxed for 15 min to remove the CO2 and precipitated from HCl
(37%). The precipitate was washed three times with water and
twice with ether before it was freeze-dried. Ion exchange with
refined by least-squares procedures on F2 with the SHELXL-97
program [31] using the integrated system WINGX [32].
H
attached to carbon or oxygen atoms were introduced at calculated
positions and treated as riding on their parent atoms
ꢀ
ꢀ
579
mL (0.1996 M, 116 mmol, 48 eq) of NaOH yielded 27 mg of
[d(CH) ¼ 0.93e0.97 A and d(OH) ¼ 0.82 A] with a displacement
parameter equal to 1.2Ueq (C6H5, C5H5, CH2, OH) times that of the
parent atom. The Molecular view was realised with the help of
ORTEP-III [33] and the packing view was done using PLATON [34].
Crystal data and refinement parameters are shown in Table 1, bond
lengths and angles in Table 2.
dendrimer 13-GL3 (1.19
mmol, 39%) as an orange powder.
1H NMR (300 MHz, DMSO-d6): 3.22e3.41 (m, 102H, CH3Ne
P1,2,3), 3.90 (s, 48H, Cp), 3.97 (s, 48H, Cp), 4.21 (s, 48H, Cp), 4.48
3
(s, 48H, Cp), 6.39 (d, JHH ¼ 15.6 Hz, 48H, CH]CHeCOO), 7.39 (d,
3JHH
¼
15.6 Hz, 48H, CH]CHeCOO), 6.95e7.82 (m, 402H,
CHarom þ CH]N). 31P{1H} NMR (121.5 MHz, CDCl3): 8.17 (s, P0),
60.8 (s, P1), 61.4 (s, P3), 62.9 (s, P2).
Acknowledgements
A
13C NMR spectrum could not be taken due to a limited solu-
bility and low concentration.
Thanks are due to the EC for the ESR Marie Curie NANOTOOL,
especially for a grant to E. de J., and to the CNRS and the ANR
DendSwitch for financial support.
4.14. Cyclic Voltammetry
The CV measurements of dendrimer 3 ꢀ GL1 were carried out with
an Autolab PGSTAT100 controlled by GPES 4.09 software and per-
formed in a homemade three electrode cell. The reference electrode
was a saturated calomel electrode, separated from the aqueous
solution by a bridge compartment. The counter electrode was a plat-
inum wire with an approximate surface area of 1 cm2. The working
electrode was a platinum electrode (0.5 mm diameter). The den-
drimer concentration was 3.73 mM and the supporting electrolyte
(KCl) concentration was 100 mM in water. Before each measurement,
the solution was degassed with argon and the working electrode was
polished with a polishing machine (Presi P230).
Appendix A. Supplementary material
CCDC 842974 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.
References
[1] B. Alonso, I. Cuadrado, M. Moran, J. Losada, J. Chem. Soc. Chem. Commun.
(1994) 2575e2576.
[2] A.M. Caminade, C.O. Turrin, R. Laurent, A. Ouali, B. Delavaux-Nicot (Eds.),
Dendrimers. Towards Catalytic, Material and Biomedical Uses, John Wiley and
Sons, Chichester, UK, 2011.
4.15. X-ray crystallography
[3] (a) C. Valerio, J.L. Fillaut, J. Ruiz, J. Guittard, J.C. Blais, D. Astruc, J. Am. Chem.
Soc. 119 (1997) 2588e2589;
(b) M.C. Daniel, J. Ruiz, D. Astruc, J. Am. Chem. Soc. 125 (2003) 1150e1151;
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