Water soluble ferrocenyl and polyferrocenyl compounds: Synthesis and electrochemistry

Article abstract of DOI:10.1016/S0022-328X(01)00959-7

The preparation and the electrochemical properties of different classes of water soluble ferrocenyl and multiferrocenyl compounds are described. Two strategies have been applied: (1) molecules with up to four redox units have been synthesized by quaterniz

Full text of DOI:10.1016/S0022-328X(01)00959-7

Journal of Organometallic Chemistry 637–639 (2001) 595–608
www.elsevier.com/locate/jorganchem
Water soluble ferrocenyl and polyferrocenyl compounds: synthesis
and electrochemistry
Alexander Salmon, Peter Jutzi *
Uni6ersita¨t Bielefeld, Fakulta¨t fu¨r Chemie-Anorganische Chemie III, Uni6ersita¨tstrasse 25, Postfach 10 01 31, D-33501 Bielefeld, Germany
Received 7 February 2001; received in revised form 30 March 2001; accepted 1 May 2001
Abstract
The preparation and the electrochemical properties of different classes of water soluble ferrocenyl and multiferrocenyl
compounds are described. Two strategies have been applied: (1) molecules with up to four redox units have been synthesized by
quaternization of 2-(N,N-dimethylamino)ethylferrocene or 1,1%-bis(2-(N,N-dimethylamino)ethyl)ferrocene with different organic
halides; (2) the synthesis of compounds with four and more redox moieties is based on the use of well established poly(propylene
imine) dendrimers; the reductive amination of formyl ferrocene with the NH2-functions of these macromolecules leads to
ferrocenyl dendrimers with a maximum of 64 metallocene units. The multi ammonium salts of these compounds exhibit solubility
only in polar solvents. All prepared ferrocenes have been studied with voltammetric, amperometric and coulometric techniques.
© 2001 Elsevier Science B.V. All rights reserved.
Keywords: Electrochemistry; Ferrocenyl compounds; Dendrimers; Water solubility
stituted ferrocenes with several organic bromides; this
reaction leads to molecules with up to four redox
moieties. The class II compounds 13b–17b with higher
molar weight are prepared by functionalization of
poly(propylene imine) dendrimers [7] with appropri-
ately substituted ferrocenes; this strategy leads to
molecules with up to 64 redox moieties. Voltammetric,
coulometric and amperometric techniques have been
applied to characterize the different ferrocenyl
compounds.
1. Introduction
In recent years many groups have focused their re-
search interests on the synthesis and electrochemical
investigation of redox active compounds useful for
electrochemical applications. For example, ferrocenyl
and multiferrocenyl systems have been used as redox
sensors for molecular recognition [1], as mediators in
amperometric biosensors [2], as building blocks in poly-
mers [3] or as coatings to modify electrode surfaces [4].
Most of the known compounds are only soluble in
hydrophobic media, only few ferrocenyl and polyferro-
cenyl systems are water soluble [5]; such species are of
particular interest as redox mediators, for example in
scanning electrochemical microscopy (SECM) [6] inves-
tigations in biological systems. Here we report on the
preparation and on the electrochemical properties of
two different classes of ammonium compounds contain-
ing ferrocenyl systems. The synthesis of the class I
compounds 3–10 with rather low molar weight is based
on the quaternization of two dimethylaminoethyl sub-
2. Results
2.1. Synthesis
2-(N,N-Dimethylamino)ethylferrocene (1) [8] or 1,1%-
bis(2-(N,N-dimethylamino)ethyl)ferrocene
(2)
[9]
(Scheme 1) were used as starting material for the syn-
thesis of the ferrocenyl ammonium salts 3, 4, 5, 6 and 7.
Treatment of solutions of the benzylic bromides based
on toluene, xylene, mesitylene and durene with fer-
rocenes 1 or 2 led to orange reaction mixtures which
turned turbid soon after the addition due to the forma-
tion of the products.
* Corresponding author. Tel.: +49-521-1066181; fax: +49-521-
1066026.
E-mail address: peter.jutzi@uni-bielefeld.de (P. Jutzi).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00959-7

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A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
Table 1
1H-NMR data of compounds 4–7 in DMSO-d6; shifts in ppm
Compound
4 (FcBz
)
5 (Fc2)
6 (Fc3)
7 (Fc4)
Number of
redox units
NCH3
NCH2CH2
NCH2CH2
Cp–H
1
2
3
4
Scheme 1.
3.04
3.45
2.83
4.13–4.17
4.64
3.05
3.47
2.85
4.14–4.18
4.68
3.10
3.54
2.89
4.14–4.24
4.67
3.12
3.97
2.90
4.16–4.28
5.12
Compounds 3–7 (Scheme 2) could be obtained as
slightly hygroscopic bright yellow solids which are only
soluble in polar solvents like EtOH, DMSO and water.
However, the solubility of these compounds decreases
with their molar weight. In the 1H-NMR spectra of
compounds 3–7 the signals for the protons are gener-
ally shifted to lower field compared to those of the
parent ferrocenes 1 and 2 due to the presence of the
positively charged ammonium groups. The lowfield
shift also depends on the number of positive charges
per molecule. In general, an increase of positive charges
causes an increase of the proton shift to lower field.
Especially the values for the aromatic protons which
increase in the sequence 4“5“6“7 from 7.53 to 8.27
exhibit this effect. In Table 1 the proton shifts of 4–7
(which are all based on ferrocene 1) are given. The
increasing number of charges also has an influence on
CH2–benzyl
CH–phenyl
7.53–7.59
7.73
7.89
8.27
the redox potentials of the ferrocenyl systems (see Sec-
tion 2.2).
To improve the solubility of this kind of ferrocenyl
systems we introduced additionally to the NR+4 group
another hydrophilic function. The mixed ammonium
salts 8, 9 and 10 (Scheme 3) could be prepared in a two
step synthesis. First the reaction of 2-(N,N-dimethyl-
amino)ethanol with only one CH2Br function of 1,4-
bis(bromomethyl)benzene or 1,3,5-tris(bromomethyl)-
benzene led to the mono ammonium compounds 11
and 12 in acceptable yields. Compounds 11 and 12
Scheme 2. Synthesis of 3, images of compounds 4, 5, 6 and 7.

A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
597
Scheme 3. Synthesis of 8, 9 and 10.
possess one OH-function in addition to the NR4+
group; one (11) or two (12) CH2Br functions are still
left for the second synthetic step, the linkage with the
redox moieties of 1 and 2. Compounds 8, 9 and 10
could be obtained in good yields as slightly hygroscopic
yellow solids which exhibit excellent solubility in EtOH,
DMSO and water.
The preparation of multiferrocenyl compounds with
up to 64 redox centers is based on the reductive amina-
tion of formyl ferrocene with different poly(propylene
imine) dendrimers. In the first step the amino functions
of the dendrimer were condensed with the aldehyde in
toluene solution. The subsequent reduction of the
formed imino groups with NaBH4 in EtOH led to
compounds with 4 (13a), 8 (14a), 16 (15a), 32 (16a), or
64 (17a) ferrocene moieties per molecule. The amino
systems could be obtained as red waxy solids in good
yields which are only soluble in organic solvents such as
CH2Cl2, CHCl3 and toluene. The quaternization of all
NR3 and NR2H fragments in these molecules with HCl
gas causes a drastic change in solubility from non polar
to polar solvents. The substituted ammonium ferro-
cenyl systems 13b–17b could be isolated as bright yel-
low solids which are only soluble in solvents like
DMSO, EtOH and water. The larger systems with 32
and 64 redox moieties per molecule exhibit only poor
solubility in DMSO or DMSO+water mixtures.
Scheme 4 presents the synthesis of the tetraferro-
cenyl compound and a representation of the multiferro-
cenyl systems with 8, 16, 32 and 64 redox units per
molecule.
1
All compounds have been characterized by H- and
13C-NMR spectroscopy and by mass spectrometry
(MALDI TOF). For the smaller systems with up to
eight redox units an exact assignment of the proton and
carbon shifts to the inner and outer methylene groups is

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A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
possible. In the spectra of the larger compounds the
different signals of the dendritic methylene groups are
no longer distinguishable. Only the signals of the re-
spectve ferrocene units and of their a methylene groups
could be separated and appear in the expected region.
The NH+2 and NH+ groups in 13b–17b are revealed by
signals at 9.4 and 11.1 ppm, respectively. The ratio of
the integrals for the NH+2 and for the NH+ resonance
is nearly two to one due to a complete protonation of
all inner and outer amino functions of 13a–17a. In
mass spectrometric investigations the amino and the
corresponding ammonium systems show the same m/z
peaks in form of the deprotonated species; this can be
explained by the loss of HCl during vaporization from
the MALDI matrix. All the collected NMR spectro-
scopic and mass spectrometric data reveal that the
functionalization of the dendrimer with redox moieties
is rather complete. Only the mass spectra of the large
systems (16a,b and 17a,b) indicate that the dendrimer
periphery is not perfectly covered with ferrocene units.
2.2. Voltammetric experiments
We examined the compounds 1–10 and 13a(b)–
17a(b) by cyclovoltammetry and square wave voltam-
metry and compared their electrochemical data. In
Table 2 the E1/2 values (vs. fc/fc+) of the ammonium
compounds in DMSO+0.1
M
TBAPF are
summarized.
In 1–10 the reversibility of the redox processes is
indicated by the fact that the observed peak separations
of all cyclic voltammograms were comparable to the
Scheme 4. Synthesis of 13b, images of 14b, 15b, 16b and 17b.

A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
599
Scheme 4. (Continued)
DEp values of decamethylferrocene which was used as
internal reference. The Eꢀ values of the square wave
voltammograms confirm the reversibility. All ferrocenyl
ammonium compounds are more difficult to oxidize
than ferrocene. The anodic shift towards the parent
ferrocenes 1 and 2 are 170 mV (3 and 9) and 60 to 80
mV (4–7, 8 and 10), respectively. This behavior can be
explained by the different substitution pattern of the
redox moieties of 3–10. The two positively charged
ammonium functions in 3 and 9 cause a larger anodic
shift of the E1/2 value than the only one function in the
other compounds. For the compounds 4–7 the increas-
ing number of positive charges per molecule also slightly
influences the redox potential. The anodic shift of E1/2
in the sequence 4“5“6“7 amounts to 20 mV.
In voltammetric measurements the multiferrocenyl
compounds 13a(b) to 17a(b) show only one redox signal
for a multi electron transfer. No interactions between the
redox moieties can be observed. The redox potential of
the ferrocenyl amines 13a to 17a amounts to 10–50 mV
(in CH2Cl2 vs. fc/fc+). Compared to the poly(propylene
imine) dendrimers of Cuadrado and Mora´n [10] with a
half-wave potential of 570–590 mV (in CH2Cl2 vs. SCE;
equals 110–130 mV vs. fc/fc+ [11]) the values of 13a to
17a are cathodically shifted (the potential difference
amounts to 80–100 mV). The molecules also adsorb
onto the working electrode surface during the electro-
chemical experiment. The potentials of the correspond-
ing ammonium salts 13b–17b amount to 90 mV each (in
DMSO vs. fc/fc+). In comparison with the ferrocenyl
systems above, the half wave potentials are anodically
shifted due to a shorter bridge between the positively
charged ammonium group and the redox center (–CH2–
instead of –CH2CH2–). Adsorption phenomena could
not be observed.
2.3. Coulometric and amperometric experiments
The diffusion coefficients D for the ammonium com-
pounds were measured by coulometric and amperomet-
ric experiments in DMSO solution relatively to ferrocene
as standard. The obtained D values and the determined
hydrodynamic radii (Stokes radii [12]) represent the
average of several measurements; the values are listed in
Table 3. Fig. 1 shows the diffusion coefficients as a
function of the molar weight of the respective ferrocenyl
system. As expected the D values decrease with increase
of the molar weight M, an adaption of the para-
meters gives the following correlation: DꢀM−0.67
.
Similar correlations have been found for macromolecu-
lar systems like ferrocenyl polymers as well as proteins
[13].

600
A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
Scheme 4. (Continued)
For the dendritic multiferrocenyl systems 13b to 17b
an expected increase of the hydrodynamic radii is ob-
The hydrodynamic radii give an impression of the
dimension of the synthesized compounds in solution
where they are surrounded by a solvating envelope.
These values are calculated as Stokes radii for ball
shaped molecules. A computer simulation (molecular
mechanics MM+) of poly(propylene imine) den-
drimers [15] shows that these macromolecules (espe-
cially the dendrimers of the fourth and fifth generation)
have the shape of a ‘drop’ or of an ellipse [16] where the
peripheric functions represent the surface of the
molecule; the inner butylene unit of the dendrimer is
situated in a cavity (the thinnest part of the ‘drop’). The
hydrodynamic radius for the largest synthesized system
,
served. The increase amounts to 9.0–9.5 A per genera-
tion. A linear dependence of these parameters as
presented in Fig. 2 is typical of dendritic systems [16].
3. Conclusion
The preparation of two classes of hydrophilic ferro-
cenyl and multiferrocenyl ammonium compounds has
been described. The first class includes systems with up
to four redox units per molecule. Their synthesis is
based on the quaternization of the amino ferrocenes 1
and 2 with different organic halides. This reaction type
offers also the access to mixed quaternary systems
which have an additional hydrophilic function (OH
group). All products 3–10, especially the compounds
with hydroxy groups (8–10), show the desired solubility
in polar solvents. Multiferrocenyl compound with up to
,
(17b) amounts to 47 A (Stokes radius). This value is
large compared to the corresponding MM+ modeled
,
system which has a maximal diameter of 27 A. The
difference between these two values indicates that 17b is
surrounded by a bulky solvating envelope in DMSO
solution; this behavior is not unusual for polar com-
pounds dissolved in polar solvents.

A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
601
Scheme 4. (Continued)
The diffusion coefficients of the ferrocenyl systems
could be determined by chronocoulometry and
chronoamperometry in DMSO solution. The obtained
values are a function of the molar weight of the
molecules and allow the calculation of the hydrody-
namic radii. For the dendritic systems 13b–17b a linear
correlation between the radius and the number of gen-
erations could be observed.
64 redox units (class II) have been prepared by func-
tionalization of poly(propylene imine) dendrimers. The
reductive amination of formyl ferrocene with these
polyamino compounds and subsequent protonation
with HCl leads to the polyammonium systems 13b–
17b.
Voltammetric investigations of the ferrocenyl systems
show that the redox potential depends on the length of
the carbon bridge between redox centre and the respec-
tive ammonium group. For the compounds based on
amino ferrocene 1 (4–7) E1/2 values from 40 to 60 mV
are obtained. The values for 3 and 9 (both based on
ferrocene 2) with two positive charges near the redox
centre amount to 80 mV. For the multiferrocenyl com-
pounds 13b–17b the redox potentials amount to 90 mV
(all vs. fc/fc+).
4. Experimental
4.1. General
All experiments were carried out under argon. Sol-
vents were dried and purified by distillation. Commer-

602
A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
Scheme 4. (Continued)
cially available starting materials were used without
further purification. Poly(propylene imine) dendrimers
were purchased from Aldrich. 1,1%-bis(2-(N,N-
dimethylamino)ethyl)ferrocene (2) [9], 1-chloro-2-N,N-
dimethylaminoethane [8], Fe(C5H5)(C5H4Li) [17],
1,3,5-tris(bromomethyl)benzene and 1,2,4,5-tetrakis-
(bromomethyl)benzene [18] were prepared as de-
scribed. NMR measurements: Bruker Avance DRX
500 (1H-NMR: 500.1 MHz; 13C{1H}-NMR: 125.8
MHz). Chemical shifts are given relative to SiMe4.
Mass spectra: PE Biosystems Voyager System 1161,
MALDI-TOF with dihydroxy benzoic acid (DHB) as
matrix. Only characteristic m/z values are listed.
Compounds 15b–17b tend to include solvent
4.2. Electrochemistry
The electrochemical experiments were performed
with a EG&G PARC Model 273A potentiostat/gal-
vanostat in combination with the Model 270 software.
A three-electrode configuration was employed. The
working electrode was a platinum disc (diameter 2
mm). The counter electrode was a platinum wire. A
silver wire was used as pseudo reference electrode. The
potentials were referenced to that of decamethylfer-
rocene as the internal reference [19]. DMSO (commer-
cially available) or CH2Cl2 (each containing 0.1 M
NBu4PF6 (TBAPF) as the supporting electrolyte) was
used as the solvent for the measurements. All potentials
were determined by cyclovoltammetry (scan rate 100
mV s−1) and square-wave voltammetry (frequency 5
1
molecules in the dendritic cavities, as detected by H-
NMR spectroscopy [10a].

A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
603
Table 2
Redox potentials E1/2 of compounds 1–10 and 13b–17b; in DMSO+
0.1 M TBAPF relative to ferrocene/ferrocenium
Compound
Number of redox E1/2 (vs. fc/fc+
)
units
(mV)
1
1
1
2
3
4
1
2
−20
40
40
50
60
4 (FcBz
5 (Fc2)
6 (Fc3)
7 (Fc4)
)
8 (FcOH
)
40
40
10 (2FcOH
)
2
1
1
1
−90
80
80
3 (Fc2Bz
)
9 (Fc2OH
)
Fig. 1. Plot of diffusion coefficients D versus molar weight M of the
compounds given in Table 3.
13b (DAB–Fc-4×6HCl)
14b (DAB–Fc-8×14HCl)
15b (DAB–Fc-16×30HCl)
16b (DAB–Fc-32×62HCl)
4
8
16
32
90
90
90
90
KOH solution is added dropwise till the color of the
organic layer turns red. The organic layer is separated,
washed twice with 50 ml water and dried over Na2SO4.
After removing the solvent 1 can obtained as red oil.
Yield: 42% (1.02 g, 4.0 mmol). 1H-NMR (CDCl3):
l=2.25 (s, 6H, CH3); 2.43 (m, 2H, CpCH2); 2.48 (m,
2H, CH2N); 4.03 (s, 2H, CpH); 4.07 (s, 2H, CpH); 4.08
(s, 5H, CpH). E1/2= −20 mV (DMSO+0.1 M
TBAPF; vs. fc/fc+). See also [8].
17b (DAB–Fc-64×126HCl) 64
90
Hz). The diffusion coefficients D were determined by
chronocoulometry and chronoamperometry as double
step experiment relative to the value of ferrocene
(6.50×10−6 cm2 s−1 [20]).
4.3. Synthesis of 2-(N,N-dimethylamino)ethylferrocene
(1)
4.4. Synthesis of 3 (Fc2Bz
)
A solution of 1.0 g (9.8 mmol) 1-chloro-2-N,N-
dimethylaminoethane in 15 ml THF was added slowly
to a stirred suspension of Fe(C5H5)(C5H4Li) in 40 ml
THF at room temperature (r.t.). After the addition the
mixture is stirred for 14 h. The solvent is removed in
vacuo and the residue is suspended in 50 ml petroleum
ether and filtered. The solution is treated with 50 ml
diluted HCl. The aqueous layer is separated and treated
with 50 ml CH2Cl2. To the stirred mixture concentrated
Bromomethylbenzene (2.8 g, 16.4 mmol) are added
to a solution of 0.47 g (1.43 mmol) 1,1%-bis(2-(N,N-
dimethylamino)ethyl)ferrocene in 20 ml hexane at r.t.
After the addition the orange solution turns turbid. The
mixture is stirred for 14 h. The solvent is removed in
vacuo and the residue is washed twice with 15 ml
hexane. Compound 3 can be obtained as yellow solid.
1
Yield: 85% (0.82 g, 1.22 mmol). H-NMR (DMSO-d6):
l=2.87 (m, 4H, CpCH2CH2N); 3.06 (s, 12H, CH3)
Table 3
Diffusion coefficients D and hydrodynamic radii rhyd of compounds 3–10, 13b–17b, ferrocene and acetyl ferrocene
Molar weight (g mol−1
)
Diffusion coefficient D (cm2 −1×10−6
s )
Hydrodynamic radius rhyd (A)
,
Compound
Ferrocene
Acetyl ferrocene
186.04
228.07
428.19
610.25
670.35
778.26
960.32
1034.47
1128.33
1327.48
1478.40
2868.11
5949.19
6.70
4.71 [14]
2.78
2.38
1.13
1.89
1.54
1.31
1.23
1.17
1.12
0.69
0.37
0.31
0.24
1.7
2.3
4.0
4.6
9.7
5.8
7.1
8.4
9.0
9.4
9.9
15.9
29.6
36.0
46.6
4 (FcBz
)
8 (FcOH
3 (Fc2Bz
5 (Fc2)
)
)
10 (2FcOH
)
9 (Fc2OH
)
6 (Fc3)
13b (DAB–Fc-4×6HCl)
7 (Fc4)
14b (DAB–Fc-8×14HCl)
15b (DAB–Fc-16×30HCl)
16b (DAB–Fc-32×62HCl) 12111.53
17b (DAB–Fc-64×126HCl) 24436.19

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A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
3.50 (m, 4H, CpCH2CH2N) 4.13 (s, 2H, CpH); 4.21 (s,
2H, CpH); 4.69 (s, 4H, CH2Ph); 7.53 (m, 6H, PhH);
7.61 (m, 4H, PhH). 13C-NMR (DMSO-d6): l=21.9
(CpCH2CH2N); 49.1 (CH3); 63.5 (CH2Ph); 66.2
(CpCH2CH2N); 68.5, 68.7, 83.2 (Cp–C); 128.2, 128.9,
130.3, 133.0 (Ph–C). Anal. Calc. for C32H42N2Br2Fe×
0.5H2O: (679.37 g mol−1): C, 56.49; H, 6.52; N, 4.12
[21]. Found: C, 56.82; H, 6.51; N, 3.92%. E1/2=80 mV
(DMSO+0.1 M TBAPF; vs. fc/fc+). D=1.13×10−6
cm2 s−1 (DMSO+0.1 M TBAPF).
hexane. Compound 5 can be obtained as yellow solid.
Yield: 95% (0.45 g, 0.58 mmol). H-NMR (DMSO-d6):
1
l=2.85 (m, 4H, CpCH2CH2N); 3.05 (s, 12H, CH3);
3.47 (m, 4H, CpCH2CH2N); 4.14 (s, 4H, CpH); 4.18 (s,
14H, CpH); 4.68 (s, 4H, CH2Ph); 7.73 (s, 4H, PhH).
13C-NMR (DMSO-d6): l=21.9 (CpCH2CH2N); 49.2
(CH3); 63.5 (CH2Ph); 65.6 (CpCH2CH2N); 67.5, 67.9,
68.5, 82.8 (Cp–C); 130.1, 133.4 (Ph–C). Anal. Calc.
for C36H46N2Br2Fe2 (778.26 g mol−1): C, 55.56; H,
5.95; N, 3.60. Found: C, 55.41; H, 6.04; N, 3.63%.
E
1/2=40 mV (DMSO+0.1 M TBAPF; vs. fc/fc+).
4.5. Synthesis of 4 (FcBz)
D=1.89×10−6 cm2 s−1 (DMSO+0.1 M TBAPF).
The preparation of 4 is similar to that of 3 above (2.9
g (17.0 mmol) bromomethylbenzene, 0.18 g (0.70
mmol) 2-(N,N-dimethylamino)ethylferrocene in 20 ml
CH2Cl2). Yellow solid. Yield: 83% (0.25 g, 0.58 mmol).
1H-NMR (DMSO-d6): l=2.83 (m, 2H, CpCH2CH2N);
3.04 (s, 6H, CH3); 3.45 (m, 2H, CpCH2CH2N); 4.13 (s
2H, CpH); 4.16 (s, 5H, CpH); 4.17 (s, 2H, CpH); 4.64
(s, 2H, CH2Ph); 7.53 (m, 3H, PhH); 7.59 (m, 2H, PhH).
13C-NMR (DMSO-d6): l=21.9 (CpCH2CH2N); 49.1
(CH3); 63.3 (CH2Ph); 66.4 (CpCH2CH2N); 67.5, 67.8,
68.5, 82.8 (Cp–C); 128.1, 130.0, 130.3, 133.0 (Ph–C).
Anal. Calc. for C21H26NBrFe×0.75H2O (441.71 g
mol−1): C, 57.10; H, 6.28; N, 3.17 [21]. Found: C,
57.10; H, 6.23; N, 3.46%. E1/2=40 mV (DMSO+0.1
M TBAPF; vs. fc/fc+). D=2.78×10−6 cm2 s−1
(DMSO/0.1 M TBAPF).
4.7. Synthesis of 6 (Fc3)
The preparation of 6 is similar to that of 5 above
(0.44
g (1.71 mmol) 2-(N,N-dimethylamino)ethyl-
ferrocene, 0.2 g (0.56 mmol) 1,3,5-tris(bromomethyl)-
benzene in 15 ml MeCN). Yellow solid. Yield: 83%
(0.47 g, 0.58 mmol). 1H-NMR (DMSO-d6): l=2.89 (m,
6H, CpCH2CH2N); 3.10 (s, 18H, CH3), 3.54 (m, 6H,
CpCH2CH2N); 4.14 (s, 6H, CpH); 4.18 (s, 15H, CpH);
4.24 (s, 6H, CpH); 4.67 (s, 6H, CH2Ph); 7.89 (s, 3H,
PhH). 13C-NMR (DMSO-d6): l=22.2 (CpCH2CH2N);
49.0 (CH3); 64.1 (CH2Ph); 65.4 (CpCH2CH2N); 67.5,
68.0, 68.6, 82.8 (Cp–C); 129.5, 139.1 (Ph–C). Anal.
Calc. for C51H66N3Br3Fe3×2H2O (1164.40 g mol−1):
C, 52.96; H, 6.06; N, 3.61 [21]. Found: C, 52.96; H,
6.13; N, 3.62%. E1/2=50 mV (DMSO+0.1 M TBAPF;
vs. fc/fc+). D=1.23×10−6 cm2 s−1 (DMSO+0.1 M
TBAPF).
4.6. Synthesis of 5 (Fc2)
2-(N,N-Dimethylamino)ethylferrocene (0.32 g, 1.24
mmol) was added to a solution of 0.16 g (0.61 mmol)
1,4-bis(bromomethyl)benzene in 25 ml MeCN at r.t.
After the addition the orange solution turns turbid. The
mixture was stirred for 14 h. The solvent was removed
in vacuo and the residue was washed twice with 20 ml
4.8. Synthesis of 7 (Fc4)
The preparation of 7 is similar to that of 5 above
(1.00
g (3.89 mmol) 2-(N,N-dimethylamino)ethyl-
ferrocene, 0.20 g (0.44 mmol) 1,2,4,5-tetrakis(bro-
momethyl)benzene in 25 ml MeCN, stirred for 4 days).
Fig. 2. Plot of hydrodynamic radii versus number of generation of compounds 13b–17b.

A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
605
Yellow solid. Yield: 84% (0.55 g, 0.37 mmol). 1H-
NMR (DMSO-d6): l=2.90 (m, 8H, CpCH2CH2N);
3.13 (s, 24H, CH3), 3.97 (m, 8H, CpCH2CH2N); 4.16
(s, 8H, CpH); 4.24 (s, 20H, CpH); 4.28 (s, 8H,
CpH); 5.12 (s, 8H, CH2Ph); 8.27 (s, 2H, PhH). 13C-
NMR (DMSO-d6): l=22.2 (CpCH2CH2N); 48.5
(CH3); 61.7 (CH2Ph); 64.6 (CpCH2CH2N); 67.5, 68.0,
68.6, 82.7 (Cp–C); 131.9, 141.9 (Ph–C). Anal. Calc.
for C66H86N4Br4Fe4×4H2O (1550.52 g mol−1): C,
51.13; H, 6.11; N, 3.61 [21]. Found: C, 51.22; H,
4.11. Synthesis of 9 (Fc2OH
)
The preparation of 9 is similar to that of 5 above
(0.20 g (0.61 mmol) 1,1%-bis(2-(N,N-dimethylamino)-
ethyl)ferrocene, 0.78 g (2.20 mmol) 11 in 70 ml MeCN).
1
Yellow solid. Yield: 79% (0.52 g, 0.48 mmol). H-NMR
(DMSO-d6): l=2.91 (m, 4H, CpCH2CH2N); 3.07 (s,
12H, CH3); 3.12 (s, 12H, CH3); 3.45 (m, 4H,
CH2CH2OH); 3.63 (m, 4H, CpCH2CH2N); 3.92 (s, 4H,
NCH2CH2OH); 4.16 (s, 4H, CpH); 4.27 (s, 4H, CpH);
4.71 (s, 2H, CH2Ph); 4.81 (s, 2H, CH2Ph); 5.39 (s br,
2H, OH); 7.74 (s br, 8H, PhH). 13C-NMR (DMSO-d6):
l=22.0 (CpCH2CH2N), 49.1, 49.9 (CH3); 54.9
(CH2OH); 63.7, 65.0, 65.2, 66.5 (NCH2); 68.3, 68.8,
83.3 (Cp–C); 130.1, 133.3, 133.5 (PhC). Anal. Calc. for
C42H66N4Br4FeO2×0.5H2O (1043.50 g mol−1): C,
48.34; H, 6.47; N, 5.37 [21]. Found: C, 48.30; H, 7.09;
N, 5.34%. E1/2=80 mV (DMSO+0.1 M TBAPF; vs.
fc/fc+). D=1.31×10−6 cm2 s−1 (DMSO+0.1 M
TBAPF).
6.18; N, 3.65%.
E1/2=60 mV (DMSO+0.1 M
TBAPF; vs. fc/fc+). D=1.12×10−6 cm2 s−1
(DMSO+0.1 M TBAPF).
4.9. Synthesis of 11 (1Bz1OH)
A solution of 0.35 g (3.93 mmol) 2-(N,N-dimethy-
lamino)ethanol in 20 ml MeCN was added slowly to
a solution of 1.50 g (5.68 mmol) 1,2-bis(bromom-
ethyl)benzene in 50 ml MeCN at r.t. After the addi-
tion the solution turned turbid and the mixture was
stirred for 5 h. The precipitate was removed by filtra-
tion and the solvent was removed in vacuo. After
washing the residue three times with 20 ml Et2O 11
was obtained as white solid. Yield: 30% (0.42 g, 1.19
mmol). 1H-NMR (CD3CN): l=3.08 (s, 6H, CH3);
3.47 (m, 2H, CH2OH); 4.02 (m, 2H, NCH2CH2OH);
4.61 (s, 2H, CH2Ph); 4.66 (s, 2H, CH2Ph); 4.83 (t,
3JH–H=5.5 Hz, 1H, OH), 7.54 (d, 3JH–H=8.2 Hz,
2H, PhH); 7.60 (d, 3JH–H=8.2 Hz, 2H, PhH). 13C-
NMR (CD3CN): l=33.5 (BrCH2Ph); 51.4 (CH3);
56.2 (CH2OH); 66.6 (CH2Ph); 68.6 (NCH2CH2OH);
128.8, 130.5, 134.7, 141.7 (Ph–C).
4.12. Synthesis of 12 (1Bz2OH)
The preparation of 12 is similar to that of 11 above
(0.30 g (3.36 mmol) 2-(N,N-dimethylamino)ethanol in
20 ml MeCN, 1.50 g (4.20 mmol) 1,3,5-tris(bro-
momethyl)benzene in 50 ml MeCN). White solid. Yield:
1
21% (0.31 g, 0.70 mmol). H-NMR (DMSO-d6): l=
3.04 (s, 6H, CH3); 3.41 (s, 2H, NCH2CH2OH); 3.91 (s,
2H, NCH2CH2OH); 4.67 (s, 2H, PhCH2N); 4.74 (s, 4H,
PhCH2Br); 5.40 (s br, 1H, OH); 7.62 (s, 1H, PhH); 7.68
(s, 2H, PhH). 13C-NMR (DMSO-d6): l=33.2
(PhCH2Br); 49.9 (CH3); 54.9 (NCH2CH2OH); 65.1,
66.8 (NCH2); 129.1, 131.6, 133.8, 139.3 (PhC).
4.10. Synthesis of 8 (FcOH
)
4.13. Synthesis of 10 (2FcOH
)
The preparation of 8 is similar to that of 5 above
(0.20 (0.78 mmol) 2-(N,N-dimethylamino)ethyl-
The preparation of 10 is similar to that of 5 above
(0.30 (1.17 mmol) 2-(N,N-dimethylamino)ethyl-
g
g
ferrocene, 0.20 g (0.57 mmol) 11 in 30 ml MeCN).
Yellow solid. Yield: 72% (0.25 g, 0.41 mmol). 1H-
NMR (DMSO-d6): l=2.85 (m, 2H, CpCH2CH2N);
3.04 (s, 6H, CH3); 3.07 (s, 6H, CH3); 3.42 (m, 2H,
CH2CH2OH); 3.51 (m, 2H, CpCH2CH2N); 3.92 (s,
2H, NCH2CH2OH)); 4.12 (s, 2H, CpH); 4.14 (s, 5H,
CpH); 4.18 (s, 2H, CpH); 4.68 (s, 2H, CH2Ph); 4.70
(s, 2H, CH2Ph); 5.39 (m, 1H, OH); 7.72 (s, 4H,
ferrocene, 0.25 g (0.56 mmol) 12 in 50 ml MeCN).
Yellow solid. Yield: 84% (0.45 g, 0.47 mmol). H-NMR
1
(DMSO-d6): l=2.89 (s, 4H, CpCH2CH2N); 3.13 (s,
6H, CH3); 3.16 (s, 12H, CH3); 3.50 (s, 2H,
NCH2CH2OH); 3.57 (s, 4H, CpCH2CH2N); 3.91 (s, 2H,
CH2OH); 4.12 (s, 4H, CpH); 4.20 (s, 10H, CpH); 4.26
(s, 4H, CpH); 4.74 (s br, 6H, PhCH2); 5.40 (s, 1H,
OH); 7.96 (s, 3H, PhH). 13C-NMR (DMSO-d6): l=
22.3 (CpCH2CH2N); 49.1, 50.0 (CH3); 54.9 (CH2OH);
63.8, 64.8, 65.3, 66.1 (NCH2); 68.1, 68.6, 69.2, 82.8
(Cp–C); 129.5, 139.1, 139.2 (Ph–C). Anal. Calc. for
C41H58N3Br3Fe2O×2H2O (996.38 g mol−1): C, 49.42;
H, 6.27; N, 4.22 [21]. Found: C, 49.76; H, 6.46; N,
4.45%. E1/2=40 mV (DMSO+0.1 M TBAPF; vs. fc/
PhH).
13C-NMR
(DMSO-d6):
l=21.9
(CpCH2CH2N), 49.2, 49.9 (CH3); 54.9 (CH2OH);
63.6, 65.1, 65.6, 66.6 (NCH2); 67.5, 67.9, 68.6, 82.9
(Cp–C); 130.2, 133.3, 133.5 (PhC). Anal. Calc. for
C26H38N2Br2FeO2 (610.25 g mol−1): C, 51.17; H,
6.27; N, 4.59. Found: C, 51.03; H, 6.13; N, 4.57%.
E
1/2=40 mV (DMSO+0.1 M TBAPF; vs. fc/fc+).
fc+). D=1.54×10−6 cm2 s−1 (DMSO+0.1
M
TBAPF).
D=2.38×10−6 cm2 s−1 (DMSO+0.1 M TBAPF).

606
A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
4.14. Synthesis of 13a (DAB–Fc-4)
mmol) formyl ferrocene, 0.55 g (14.5 mmol) NaBH4).
Red wax-like solid. Yield: 89% (1.47 g, 0.62 mmol).
1H-NMR (CDCl3): l=1.34 (s, 4H, NCH2CH2CH2-
CH2N); 1.51 (m, 8H, NCH2CH2CH2N); 1.59 (m, 16H,
NCH2CH2CH2NH); 2.35 (m, 20H, NCH2CH2CH2N
and NCH2CH2CH2CH2N); 2.41 (m, 16H, NCH2-
CH2CH2NH); 2.59 (t, 3JH–H=7.1 Hz, 16H,
NCH2CH2CH2NH); 3.47 (s, 16H, CpCH2), 4.07 (s,
16H, CpH); 4.09 (s, 40H, CpH); 4.15 (s, 16H, CpH).
13C-NMR (CDCl3): l=24.4 (NCH2CH2CH2N); 25.1
(NCH2CH2CH2CH2N); 27.5 (CH2CH2CH2NH); 48.2,
49.2 (CH2NHCH2); 52.2 (NCH2CH2CH2NH); 52.4
(NCH2CH2CH2N); 54.3 (NCH2CH2CH2CH2N); 67.7,
68.4, 68.8, 86.9 (Cp–C). MS (MALDI-TOF, DHB):
m/z=2360 [M+]. E1/2=30 mV (CH2Cl2+0.1 M
TBAPF; vs. fc/fc+).
A solution of 0.48 g (1.52 mmol) DAB–Am-4 and
1.30 g (6.07 mmol) formyl ferrocene in 50 ml toluene
was heated to reflux for 6 h. After removing the solvent
in vacuo the residue was solved in 50 ml EtOH. NaBH4
(0.5 g) was added to the mixture which was heated to
reflux for 4 h. The solvent was removed in vacuo and
the residue was suspended in 70 ml CH2Cl2. The or-
ganic layer was washed three times with 50 ml water
and dried over Na2SO4. After removing the solvent 13a
was obtained as a red wax-like solid. Yield: 92% (1.55
g, 1.40 mmol). 1H-NMR (CDCl3): l=1.33 (m, 4H,
NCH2CH2CH2CH2N); 1.59 (m, 8H, NCH2CH2CH2-
NH); 2.34 (m, 4H, NCH2CH2CH2CH2N); 2.40 (m, 8H,
NCH2CH2CH2NH); 2.59 (t, 3JH–H=7.1 Hz, 8H,
NCH2CH2CH2NH); 3.48 (s, 8 H, CpCH2), 4.07 (s, 8H,
CpH); 4.09 (s, 20H, CpH); 4.16 (s, 8H, CpH). 13C-
NMR (CDCl3):l=24.9 (NCH2CH2CH2CH2N); 27.5
(NCH2CH2CH2NH); 48.3, 49.2 (CH2NHCH2); 52.3
(NCH2CH2CH2NH); 54.0 (NCH2CH2CH2CH2N);
67.9, 68.4, 68.5, 86.7 (Cp–C). MS (MALDI-TOF,
DHB): m/z=1109 [M+]. E1/2=30 mV (CH2Cl2+0.1
M TBAPF; vs. fc/fc+).
4.17. Synthesis of 14b (DAB–Fc-8×14HCl)
The preparation of 14b is similar to that of 13b above
(0.54 g (0.23 mmol) DAB–Fc-8 in 50 ml CH2Cl2/Et2O
(1:1)). Yellow solid. Yield 83% (0.54 g, 0.19 mmol).
1H-NMR (DMSO-d6): l=1.85 (s, 4H, NHCH2-
CH2CH2CH2NH); 2.16 (s, 16H, NHCH2CH2CH2NH2);
2.24 (s; 8H, NHCH2CH2CH2NH); 2.93 (s, 16H,
NHCH2CH2CH2NH2); 3.26 (s, 36H, CH2NHCH2); 3.95
(s, 16H, CpCH2), 4.22 (s, 40H, CpH); 4.24 (s, 16H,
CpH); 4.48 (s, 16H, CpH); 9.40 (s, 16H, NH2); 11.16 (s,
6H, NH). 13C-NMR (DMSO-d6): l=15.1, 17.1, 19.7
(CH2CH2CH2CH2 and CH2CH2CH2); 42.9, 46.0
(CH2NH2CH2); 48.4, 49.2, 52.0, (NHCH2); 68.7, 70.7,
76.5 (Cp–C). MS (MALDI-TOF, DHB): m/z=2360
[M+−14HCl]. Anal. Calc. for C128H190N14Cl14Fe8×
4H2O (2940.31 g mol−1): C, 52.29; H, 6.79; N, 6.67
[21]. Found: C, 52.11; H, 6.83; N, 6.67%. E1/2=90 mV
(DMSO+0.1 M TBAPF; vs. fc/fc+). D=0.69×10−6
cm2 s−1 (DMSO+0.1 M TBAPF).
4.15. Synthesis of 13b (DAB–Fc-4×6HCl)
Through a stirred solution of 0.40 g (0.36 mmol)
DAB–Fc-4 in 50 ml CH2Cl2/Et2O (4:1) a gentle stream
of HCl gas was bubbled for 60 min. During this time a
yellow precipitate was formed. Afterwards the mixture
was stirred another 30 min. The solvent was removed in
vacuo and the residue was washed twice with 20 ml
Et2O. Compound 13b was obtained as a yellow solid.
1
Yield: 81% (0.38 g, 0.29 mmol). H-NMR (DMSO-d6):
l=1.78 (s, 4H, NHCH2CH2CH2CH2NH); 2.13 (s, 8H,
NHCH2CH2CH2NH2); 2.89 (s, 8H, NHCH2CH2-
CH2NH2); 3.06 (m, 4H, NHCH2CH2CH2CH2NH); 3.17
(s, 8H, NHCH2CH2CH2NH2); 3.92 (s, 8H, CpCH2),
4.21 (s, 20H, CpH); 4.22 (s, 8H, CpH); 4.46 (s, 8H,
CpH); 9.38 (s, 8H, NH2); 11.13 (s, 2H, NH). 13C-NMR
(DMSO-d6): l=19.6 (NHCH2CH2CH2NH2); 19.9
(NHCH2CH2CH2CH2NH); 42.9, 46.0 (CH2NH2CH2);
49.0 (NHCH2CH2CH2NH2); 50.6 (NHCH2CH2-
CH2CH2NH); 68.7, 70.7, 76.5 (Cp–C). MS (MALDI-
TOF, DHB): m/z=1109 [M+−6HCl]. Anal. Calc. for
C60H86N6Cl6Fe4×4H2O (1399.60 g mol−1): C, 51.49;
H, 6.77; N, 6.00 [21]. Found: C, 51.36; H, 6.86; N,
5.83%. E1/2=90 mV (DMSO+0.1 M TBAPF; vs. fc/
4.18. Synthesis of 15a (DAB–Fc-16)
The preparation of 15a is similar to that of 13a above
(0.38 g (0.23 mmol) DAB–Am-16 and 0.77 g (3.60
mmol) formyl ferrocene, 0.3 g (7.9 mmol) NaBH4). Red
wax-like solid. Yield: 78% (0.89 g, 0.18 mmol). 1H-
NMR (CDCl3): l=1.54 (s br, 28H, CH2CH2CH2 and
CH2CH2CH2CH2); 1.62 (m, 32H, NCH2CH2CH2NH);
2.37 (m, 52H, NCH2); 2.44 (m, 32H, NCH2CH2CH2-
NH); 2.62 (t, 32H, 3JH–H=6.9 Hz, NCH2CH2CH2NH);
3.49 (s, 32H, CpCH2); 4.10 (s, 32H, CpH); 4.12 (s, 80H,
CpH); 4.18 (s, 32H, CpH).13C-NMR (CDCl3): l=
24.3, 24.6, 27.5 (CH2CH2CH2 and CH2CH2CH2CH2);
48.3, 49.2, 52.2; 52.4, 53.4 (CH2NCH2 and CH2-
NHCH2); 67.7, 68.4, 68.5, 87.0 (Cp–C). MS (MALDI-
fc+). D=1.17×10−6 cm2 s−1 (DMSO+0.1
TBAPF).
M
4.16. Synthesis of 14a (DAB–Fc-8)
The preparation of 14a is similar to that of 13a above
(0.54 g (0.70 mmol) DAB–Am-8 and 1.19 g (5.56
TOF, DHB): m/z=4851 [M+].
(CH2Cl2+0.1 M TBAPF; vs. fc/fc+).
E1/2=50 mV

A. Salmon, P. Jutzi / Journal of Organometallic Chemistry 637–639 (2001) 595–608
607
4.19. Synthesis of 15b (DAB–Fc-16×30HCl)
4.22. Synthesis of 17a (DAB–Fc-64)
The preparation of 15b is similar to that of 13b above
(0.30 g (6.2×10−2 mmol) DAB–Fc-16 in 50 ml
CH2Cl2/Et2O (1:2)). Yellow solid. Yield: 81% (0.30 g,
5.0×10−2 mmol). 1H-NMR (DMSO-d6): l=2.20 (s
br, 64H, CH2CH2CH2 and CH2CH2CH2CH2); 2.96 (s,
32H, NHCH2CH2CH2NH2); 3.36 (s br, 84H,
CH2NHCH2); 4.07 (s, 32H, CpCH2), 4.12 (s, 80H,
CpH); 4.23 (s, 32H, CpH); 4.50 (s, 32H, CpH); 9.45 (s,
32H, NH2); 11.14 (s, 14H, NH). 13C-NMR (DMSO-d6):
l=17.0, 19.6 (CH2CH2CH2 and CH2CH2CH2CH2);
42.9, 46.1, 49.2 (CH2NH2CH2 and CH2NHCH2); 68.1,
70.8, 76.5 (Cp–C). MS (MALDI-TOF, DHB): m/z=
4851 [M+–30HCl]. E1/2=90 mV (DMSO+0.1 M
TBAPF; vs. fc/fc+). D=0.37×10−6 cm2 s−1
(DMSO+0.1 M TBAPF).
The preparation of 17a is similar to that of 13a above
(0.50 g (7.0×10−2 mmol) DAB–Am-64 and 0.96 g
(4.48 mmol) formyl ferrocene, 0.55 g (14.5 mmol)
NaBH4). Red wax-like solid. Yield: 93% (1.29 g, 6.5×
1
10−2 mmol). H-NMR (CDCl3): l=1.52 (s br, 124H,
CH2CH2CH2 and CH2CH2CH2CH2); 1.58 (m, 128H,
CH2CH2CH2NH); 2.36 (s br, 244H, NCH2); 2.41 (m,
128H, CH2CH2CH2NH); 2.60 (m, 128H, CH2-
CH2CH2NH); 3.47 (s, 128H, CpCH2); 4.08 (s, 128H,
CpH); 4.10 (s, 320H, CpH); 4.16 (s, 128H, CpH).
13C-NMR (CDCl3): l=24.3, 27.5 (CH2CH2CH2 and
CH2CH2CH2CH2); 48.2, 49.2, 52.2 (CH2NHCH2 and
CH2NCH2); 67.8, 68.4, 68.5, 86.9 (Cp–C). MS
(MALDI-TOF, DHB): m/z=18400 broad [M+], Calc.
19842 (for C1080H1520N126Fe64).
E1/2=10 mV
(CH2Cl2+0.1 M TBAPF; vs. fc/fc+).
4.20. Synthesis of 16a (DAB–Fc-32)
4.23. Synthesis of 17b (DAB–Fc-64×126HCl)
The preparation of 16a is similar to that of 13a above
(0.55 g (0.16 mmol) DAB–Am-32 and 1.08 g (5.05
mmol) formyl ferrocene, 0.55 g (14.5 mmol) NaBH4).
Red wax-like solid. Yield: 88% (1.42 g, 0.14 mmol).
1H-NMR (CDCl3): l=1.53 (s br, 60H, CH2CH2CH2
and CH2CH2CH2CH2); 1.59 (m, 64H, CH2CH2-
CH2NH); 2.35 (s br, 116H, NCH2); 2.41 (m, 64H,
CH2CH2CH2NH); 2.60 (m, 64H, CH2CH2CH2NH);
3.47 (s, 64H, CpCH2); 4.08 (s, 64H, CpH); 4.10 (s,
160H, CpH); 4.16 (s, 64H, CpH). 13C-NMR (CDCl3):
l=24.3, 27.4 (CH2CH2CH2 and CH2CH2CH2CH2);
48.2, 49.1, 52.4 (CH2NHCH2 and CH2NH2CH2); 67.8,
68.4, 68.5, 86.8 (Cp–C). MS (MALDI-TOF, DHB):
The preparation of 17b is similar to that of 13b above
(1.02 g (5.1×10−2 mmol) DAB–Fc-64 in 80 ml
CH2Cl2/Et2O (1:1)). Yellow solid. Yield: 82% (1.02 g,
4.2×10−2 mmol). 1H-NMR (DMSO-d6): l=2.31 (s
br, 252H, CH2CH2CH2 and CH2CH2CH2CH2); 3.08 (s
br, 128H, NHCH2CH2CH2NH2); 3.41 (s br, 372H,
CH2NHCH2); 4.06 (s, 128H, CpCH2); 4.28 (s, 448H,
CpH); 4.59 (s, 128H, CpH); 9.48 (s br, 128H, NH2);
11.14 (s br, 60H, NH). [22] 13C-NMR (DMSO-d6):
l=15.1, 19.7 (br, CH2CH2CH2 and CH2CH2-
CH2CH2); 43.1, 46.1, 49.0 (br CH2NH2CH2 and
CH2NHCH2) 68.8, 70.8, 76.5 (Cp–C). MS (MALDI-
TOF, DHB): m/z=18150 broad [M+], Calc. 19842 (for
C1080H1520N126Fe64 without 126HCl). Anal. Calc. for
m/z=9540 broad [M+], Calc. 9851 (for C536
-
H
752N62Fe32). E1/2=20 mV (CH2Cl2+0.1 M TBAPF;
C
1080H1646N126Cl126Fe64 (24436.19 g mol−1): C, 53.08;
H, 6.79; N, 7.22. Found: C, 52.99; H, 7.07; N, 7.28%.
vs. fc/fc+).
E
1/2=90 mV (DMSO+0.1 M TBAPF; vs. fc/fc+).
D=0.24×10−7 cm2 s−1 (DMSO+0.1 M TBAPF).
4.21. Synthesis of 16b (DAB–Fc-32×62HCl)
The preparation of 16b is similar to that of 13b above
(0.80 g (8.1×10−2 mmol) DAB×Fc-32 in 50 ml
CH2Cl2/Et2O (3:4)). Yellow solid. Yield: 83% (0.81 g,
6.7×10−2 mmol). 1H-NMR (DMSO-d6): l=2.29 (s
br, 64H, CH2CH2CH2 and CH2CH2CH2CH2); 2.96 (s,
64H, NHCH2CH2CH2NH2); 3.40 (s br, 188H,
CH2NHCH2); 4.03 (s, 64H, CpCH2); 4.26 (s, 224H,
CpH); 4.57 (s, 64H, CpH); 9.45 (s, 64H, NH2); 11.14 (s,
30H, NH). [22] 13C-NMR (DMSO-d6): l=19.7 (br,
CH2CH2CH2 and CH2CH2CH2CH2); 43.1, 46.1, 49.2
(br, CH2NHCH2 and CH2NH2CH2) 68.8, 70.9, 76.5
(Cp–C). MS (MALDI-TOF, DHB): m/z=9460 broad
[M+], Calc. 9851 (for C536H752N62Fe32 without 62HCl).
Acknowledgements
We thank the Volkswagen–Stiftung for financial
support.
References
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E
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608
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protons are only observable in the room temperature spectrum.