Supramolecular threaded complexes from fullerene-crown ether and π-extended TTF derivatives

Article abstract of DOI:10.1002/ejoc.200700226

A series of π-extended TTFs (exTTFs) bearing one (8, 16,19) or two (14) dibenzylammonium units have been threaded through a dibenzo-24-crown-8 (DB24C8) ring covalently linked to a C₆₀ sphere. Whereas 8 and 14 were prepared in a multistep synthe

Full text of DOI:10.1002/ejoc.200700226

FULL PAPER
DOI: 10.1002/ejoc.200700226
Supramolecular Threaded Complexes from Fullerene–Crown Ether
and π-Extended TTF Derivatives
Beatriz M. Illescas,[a] José Santos,[a] Marta C. Díaz,[a] Nazario Martín,*[a]
Carmen M. Atienza,[b] and Dirk M. Guldi*[b]
Keywords: Supramolecular chemistry / Tetrathiafulvalenes / Fullerenes / Noncovalent interactions
A series of π-extended TTFs (exTTFs) bearing one (8, 16,19)
or two (14) dibenzylammonium units have been threaded
through a dibenzo-24-crown-8 (DB24C8) ring covalently
linked to a C60 sphere. Whereas 8 and 14 were prepared in
a multistep synthetic procedure involving Sonogashira cross-
coupling reactions affording rigid donors, exTTFs 16 and 19
were prepared by direct esterification reactions leading to
more flexible systems. Complexation experiments carried out
by 1H NMR titration and fluorescence studies show the for-
mation of stable supramolecular dyads with binding con-
stants ranging from 103 to 104 –1. Although the UV/Vis and
CV studies reveal the lack of interaction between the elec-
troactive species (C60 and exTTF) in the ground state, fluo-
rescence data indicate the presence of an electronic interac-
tion in the excited state.
M
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
Since photoinduced electron transfer between the donor
and C60 may take place through space, both moieties can
also be connected by means of non-covalent interactions.
Thus, C60-based supramolecular donor–acceptor dyads
have also been widely studied.[13]
Introduction
The design of new molecular materials able to harvest
and transform solar energy into chemical or electrical
power has been intensively studied over the last years.[1]
Such bio-inspired artificial systems mimic the photoinduced
electron transfer process occurring during photosynthesis,
which results in an efficient formation of the corresponding
radical ion pair species.[2] The assembly of an electron do-
nor (D) and an electron acceptor (A) provides the necessary
pathway that allows photoinduced electron transfer to oc-
cur. In this sense, fullerene C60 has been successfully used
as the acceptor moiety in the construction of model photo-
synthetic systems due to its remarkable photophysical, elec-
trochemical and chemical properties.[3]
The covalent linkage of the two electroactive donor and
acceptor fragments by means of flexible or rigid spacers has
been, by far, the most studied approach. A wide variety of
electron donor units, such as porphyrins,[4] organometallic
complexes, such as ferrocenes[5] or RuIIbipyridine,[6] caro-
tenes,[7] aniline derivatives,[8] π-conjugated oligomers,[9]
phthalocyanines[10] and tetrathiafulvalenes (TTFs)[11,12]
have been covalently linked to C60 through different chemi-
cal protocols.
Our groups have intensively worked in the preparation
and study of covalent TTF–C60 dyads, especially, in the
study of systems bearing π-extended-TTF (exTTF) as the
donor fragment.[11] Contrary to other donor fragments
such as porphyrins, π-conjugated oligomers, etc, both TTF
and exTTF undergo a strong gain of aromaticity upon oxi-
dation. Furthermore, in comparison to the parent TTF,
exTTF has proved to have exceptional properties for the
stabilization of the charge-separated states generated upon
light irradiation. Thus, the radical ion pair lifetimes of
exTTF–C60 dyads were two orders of magnitude higher
than those reported for the analogue TTF–C60 sys-
tems.[11,12]
Although there are many examples in the literature in-
volving supramolecular aspects of TTF chemistry,[14]
exTTF has been much less studied in this context, and only
a few examples have been reported. Bryce et al.[15] described
crown-annelated derivatives of exTTF 1 and 2 (Figure 1)
and exploited their chromophoric and strong π-electron do-
nor properties in the spectrophotometric and voltammetric
sensing of metal cations.
[a] Departamento Química Orgánica, Facultad de Ciencias Quím-
icas, Universidad Complutense,
28040 Madrid, Spain
Very recently in our group, exTTF has been used as a
building block for the preparation of efficient fullerene re-
ceptors of type 3. Strikingly, such exTTF based tweezers
show a unique solvent-controlled positive homotropic co-
operative binding behaviour.[16] Previously, we had reported
on the synthesis of a π-extended TTF dimer crown ether 4
Fax: +34-91-394-4103
E-mail: nazmar@quim.ucm.es
[b] Institute of Physical and Theoretical Chemistry and Interdisci-
plinary Center for Molecular Materials, University of Erlangen,
91058 Erlangen, Germany
Fax: +49-913-185-28307
E-mail: dirk.guldi@chemie.uni-erlangen.de
Eur. J. Org. Chem. 2007, 5027–5037
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
5027

N. Martín, D. M. Guldi, et al.
FULL PAPER
this supramolecular ensemble via 1H NMR titration experi-
ments and complementary fluorescence measurements.[17]
It is known that the ammonium–crown ether interactions
are relatively weak and, consequently, the binding constants
are usually low.[18] However, when additional recognition
elements are present, the stability of the complexes is dra-
matically increased. Thus, the intramolecular π-stacking be-
tween the two chromophores is responsible for the high sta-
bility of the self-assembled systems in supramolecular por-
phyrin–fullerene conjugates.[13c,19] In this sense, exTTF has
a concave aromatic surface expected to match the convex
exterior of [60]fullerene and, therefore, to establish favour-
able van der Waals and π–π interactions with it.[16] These
additional recognizing aspects should favour the self as-
sembly of complementary exTTF ammonium salts with ful-
lerene crown ethers.
In a step toward the construction of more efficient non-
covalent exTTF–C60 dyads, we report here on the self as-
sembly of a series of exTTF-based secondary ammonium
salts with fullerene C60 endowed with a DB24C8 crown
ether appendage (Figure 2).
Results and Discussion
Figure 1. Representative exTTF derivatives exploited in supramo-
lecular chemistry.
Synthesis
and its supramolecular complexation with a fullerene deriv-
The multistep preparation of the novel exTTFs 8, 14, 16
ative bearing a secondary ammonium salt. An association and 19 suitably functionalized with a dibenzylamine moiety
constant (Ka) of 50 –1 in CDCl3/CD3CN was obtained for is depicted in Schemes 1 to 4.
Figure 2. Supramolecular complexes prepared by threading the electron donor into the crown ether-containing [60]fullerene.
5028
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 5027–5037

Supramolecular Threaded Complexes
of benzylamine and 4-iodobenzaldehyde under reductive
conditions (NaBH3CN),[21] led to amine 8 in moderate yield
(49%). Finally, according to a typical protocol,[22] proton-
ation of this compound with 3  HCl (aq.) yielded the salt
8-H·PF6 after counterion exchange with saturated aqueous
NH4PF6.
The preparation of double hexafluorophosphate salt 14-
2H·2PF6 was carried out following a similar synthetic pro-
cedure in several steps, as shown in Scheme 2. Compound
11 was synthesized from 2,6-diiodo-9,10-anthraquinone (9),
which in turn was prepared by a double Sandmeyer reac-
tion from commercially available 2,6-diamino-9,10-anthra-
quinone.[23] Subsequent twofold reaction of quinone 9 with
the phosphorus-stabilized carbanion generated by treat-
ment of 10[24] with n-butyllithium, gave exTTF 11. A Sono-
gashira coupling reaction of 11 with ethynyl(trimethyl)si-
lane in the presence of Pd(PPh3)4, CuI and diisopropyl-
amine, followed by desilylation, afforded exTTF 13 in a
good overall yield (62%). Finally, the palladium/copper cat-
alyzed cross-coupling reaction combining 13 and two equiv-
alents of N-benzyl-N-(4-iodobenzyl)amine (7) gave 14-
2H·2PF6 in a moderate yield after carrying out protonation
and counterion exchange.[22]
Scheme 1.
Scheme 1 outlines the synthesis of 8-H·PF6 in which a
rigid alkynyl spacer is introduced between the exTTF moi-
ety and the dibenzylammonium unit. exTTF 6 was ob-
tained by a Sonogashira coupling reaction of 2-iodo-9,10-
bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene
(5)[20]
with ethynyl(trimethyl)silane in the presence of Pd(PPh3)4,
CuI and diisopropylamine, followed by desilylation with
K2CO3. A further Sonogashira reaction of 6, carried out
The ammonium salt 16-H·PF6 was prepared in a
under the same experimental conditions, with N-benzyl-N- multistep synthetic procedure from the previously reported
(4-iodobenzyl)amine (7), obtained in turn by condensation aldehyde 15.[11h] The reductive amination of this aldehyde
Scheme 2.
Scheme 3.
Eur. J. Org. Chem. 2007, 5027–5037
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5029

N. Martín, D. M. Guldi, et al.
FULL PAPER
with benzylamine using sodium cyanoborohydride afforded (8-H·PF6, 14-2H·2PF6, 16-H·PF6 and 19-H·PF6) could not
the corresponding secondary amine 16 (Scheme 3). Accord- be recorded. A remarkable downfield shift of the signals
ing to the above-mentioned procedure, it was protonated corresponding to the dithiole ring protons was observed in
and the counterion was exchanged to give 16-H·PF6 as an the 1H NMR spectra of the ammonium salts in comparison
orange solid in 59% overall yield.
to the corresponding neutral amines. Thus, while these pro-
The ammonium salt 19-H·PF6 was prepared starting tons are observed at δ ≈ 6.2–6.3 in the amines (8, 14, 16),
from the hydroxymethyl-exTTF derivative 17,[25] as de- they appear at δ ≈ 7.2–7.9 in the respective salts (see Experi-
picted in Scheme 4. The esterification reaction of 17 with mental Section).
an equimolar amount of 4-formylbenzoic acid in the pres-
Crown ether fullerene derivative 21 was obtained
ence of DMAP and DCC, led to the formyl-containing es- (Scheme 5) as a brown solid in 44% yield by a cycloaddition
ter 18. Further protonation (3  HCl/THF/MeOH) and reaction of C60 with the azomethine ylide generated in situ
counterion exchange (NH4PF6) of the corresponding sec- from (2-formyl)dibenzo[24]crown-8 (20)[26] and sarcosine.
ondary amine 19, obtained by reductive amination, af-
forded 19-H·PF6 as an orange solid in moderate yield (see
Experimental Section).
Complexation Studies
The new exTTF derivatives have been characterized by
FTIR, MS, 1H and 13C NMR spectroscopy. Owing to their
We have investigated the ability of the exTTF derivatives
lack of solubility, the 13C NMR spectra of the exTTF salts 8-H·PF6, 14-2H·2PF6, 16-H·PF6 and 19-H·PF6 to form
Scheme 4.
Scheme 5.
5030
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 5027–5037

Supramolecular Threaded Complexes
supramolecular complexes with crown ether fullerene 21 dominantly with photoexcited C60 and ground state exTTF.
(Figure 2). The first evidence for complexation was ob- In this light, we expected that the crown ether complexation
1
tained when comparing the H NMR spectra of the free would exert a notable impact on the singlet excited state
species with those of mixtures of the corresponding salt and deactivation of the photoexcited fullerene. In particular, the
21. Thus, upon titration of one equivalent of the corre- fullerene fluorescence of 21 (2.05ϫ10–5 ) was monitored
sponding salt with one equivalent (or two for 14-2H·2PF6) in the absence and presence of variable concentrations of
of 21, significant resonance shifts are observed. The most the different ammonium salts (i.e., typically in the range
dramatic changes mainly involve both the ammonium pro- between 1.90ϫ10–6 and 1.49ϫ10–5 ). The experimental
tons and the benzylic protons of the ammonium salt. This findings reveal that the fullerene fluorescence intensities de-
fact reveals that complexation has taken place by threading creased exponentially as the ammonium salts were added
the exTTF-containing ammonium salt through the (Figure 4). It is interesting to note that blank experiments
DB24C8 moiety of compound 21.
using C60 itself instead of 21 resulted in a quenching of the
The association constant for the formation of complex fluorescence lower than 5%, thus confirming the intramo-
1
[(16-H·PF6)·(21)] has been evaluated by H NMR binding lecular character of fluorescence deactivation in these com-
titration experiments (500 MHz, CDCl3/CD3CN, 298 K) plexes. The following quantum yields were determined:
upon addition of a solution of 21 in CDCl3 into a solution 5.8ϫ10–4 (1:1, 21/8-H·PF6), 4.9ϫ10–4 (1:1, 21/16-H·PF6),
of 16-H·PF6 in CD3CN (Figure 3). Changes in chemical 2.2ϫ10–4 (2:1, 21/14-2H·2PF6) and 4.7ϫ10–4 (1:1, 21/19-H·
shifts induced upon complexation are particularly visible PF6) (Figure 4).
for the aromatic protons of the exTTF units together with
the shifting of the ammonium signal. The most important
downfield shift of the ammonium protons (∆δ = 0.17 ppm)
has been used for the calculation of the association constant
by fitting to a 1:1 binding isotherm, affording a value of Ka
= 2.2ϫ103 –1.[27]
Figure 4. Room temperature fluorescence spectra of 21
(2.05ϫ10–5 ) in a mixture of CH3CN/CH2Cl2, 1:1 upon adding
variable concentration of 14-2H·2PF6 (1.90ϫ10–6–1.49ϫ10–5);
λexc: 345 nm.
In each individual assay, the fluorescence intensities were
1
Figure 3. Partial H NMR of 1 m 16-H·PF6 (bottom) upon ad-
corrected by a background spectrum, which was recorded
just using matching ammonium salts concentrations. In the
next, the quenching of the fullerene fluorescence was used
to analyze the association constants for the underlying
crown ether complexations [i.e., 21 with 8-H·PF6, 14-2H·
2PF6, 16-H·PF6, 19-H·PF6] through the following relation-
ship:
dition of increasing amount of C60 crown ether derivative 21 (top).
The UV/Vis spectrum of a dilute solution of 16-H·PF6
in CH2Cl2/CH3CN did not change significantly upon ad-
dition of an equimolar amount of the fullerene derivative
21, thus indicating negligible electronic interactions be-
tween the chromophores in the ground state. This observa-
tion is consistent with the electrochemical results discussed
in the following section.
The low solubility of exTTF salts (8-H·PF6, 14-2H·2PF6)
on the one hand and the high instability of 19-H·PF6 in
solution on the other, prevented the NMR titration experi-
ments with these compounds.
Using the fluorescence maxima at 709 nm, the following
In complementary work, the crown ether complexation, binding constant values were obtained: 1.4ϫ104 –1
that is, interactions between fullerene 21 and the exTTF {[(14-2H·2PF6)·(21)2]},
1.3ϫ103 –1 {[(16-H·PF6)·(21)]}
based ammonium salts [i.e., 8-H·PF6, 14-2H·2PF6, 16- and 8.6ϫ102 –1 {[(19-H·PF6)·(21)]}.
H·PF6, 19-H·PF6] were assayed by means of fluorescence
Supramolecular complexation was also evidenced by
experiments. The basis for these assays is the prominent electrospray mass spectrometry (ESI-MS). The spectrum of
electron donor–acceptor interactions as they prevail pre- an equimolecular mixture of 16-H·PF6 and 21 displayed the
Eur. J. Org. Chem. 2007, 5027–5037
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5031

N. Martín, D. M. Guldi, et al.
FULL PAPER
peak corresponding to the 1:1 complex after loss of the significantly, revealing that complexation does not influence
hexafluorophosphate counteranion.
strongly the electroactive properties of the components, and
suggesting that the electroactive units are not spatially close
enough to allow measurable electronic interactions between
them (Figure 5).
Electrochemical Studies
The redox properties of the individual components and
the [2]pseudorotaxanes were determined by cyclic voltam-
metry (CV). The measurements were carried out at room
temperature in dichloromethane/acetonitrile (1:1) using
glassy carbon (GC) as the working electrode, standard Ag/
AgCl as the reference electrode and tetrabutylammonium
hexafluorophosphate (0.1 ) as the supporting electrolyte.
The data are collected in Table 1, together with those mea-
sured for exTTF 16 as a reference.
Table 1. Redox potentials (in volts vs. Ag/AgCl) of exTTF-based
ammonium salts and supramolecular complexes at 100 mVs–1.
Compound
E1,ox
E1,red
E2,red
E3,red
16
0.11
0.19
0.25
0.12
0.02
8-H·PF6
14-2H·2PF6
16-H·PF6
19-H·PF6
21
Figure 5. Cyclic voltammograms (sweep rate 100 mVs–1) of 16,
16-H·PF6, 21, [(16-H·PF6)·(21)] in CH2Cl2/CH3CN.
–0.82
–0.81
–0.83
–0.82
–0.88
–1.22
–1.20
–1.25
–1.22
–1.18
–1.77
–1.78
–1.78
–1.78
–1.77
[(8-H·PF6)·(21)]
[(14-2H·2PF6)·(21)2]
[(16-H·PF6)·(21)]
[(19-H·PF6)·(21)]
0.20
0.27
0.18
0.09
Conclusions
Unlike the parent TTF, exTTF 16 exhibits only one two-
In summary, we have synthesized a new series of π-ex-
electron, quasireversible oxidation wave to form a dication, tended tetrathiafulvalenes (exTTFs) covalently connected
which has been confirmed by Coulombimetric analysis.[28] to a dibenzylammonium moiety through an alkynyl rigid
The coalescence of the two one-electron processes into one spacer (8) or a more flexible ester group (16, 19). A twofold
two-electron process reveals that the presence of the quino- Sonogashira reaction on the diiodo-substituted exTTF (11)
noid structure between the two 1,3-dithiole rings leads to has allowed us to obtain an exTTF (14) endowed with two
unstable, highly distorted, nonplanar radical cations.[29]
dibenzylammonium units. The resulting exTTFs (8, 14, 16
In agreement with the above data, exTTF ammonium and 19) are suitably functionalized to be threaded into a
salts exhibit only one oxidation wave to form the dication DB24C8 ring which, in turn, is linked to the efficient elec-
species, showing, however, a slightly poorer oxidation po- tron acceptor [60]fullerene through a pyrrolidine ring fol-
tential than the neutral amines (Table 1). This fact could lowing Prato’s protocol.
be explained by electrostatic repulsion between the charges
The stability of the resulting supramolecular ensembles
generated upon oxidation and the charge already present in has been determined for the complex [(16-H·PF6)·(21)] by
the ammonium salts. It is worth mentioning that the pres- 1H NMR binding titration experiments (500 MHz, CDCl3/
ence of the methyl groups on the dithiole rings in exTTF CD3CN, 298 K) because of its better solubility in compari-
results in a significant cathodic shift of the oxidation poten- son with those complexes bearing the alkynyl moiety, which
tial value of 19-H·PF6 (Table 1) due to their positive induc- showed a remarkably lower solubility, thus preventing the
tive effect, which increases the electron donor ability of this 1H NMR titration experiments. Interestingly, a binding
compound. This stronger electron-donor character resulted, constant of 2.2ϫ103 –1 was determined, which indicates
however, in a higher instability of this compound (19- the relatively high stability of these complexes. This value
H·PF6) in solution, thus accounting for the unsuccessful 1H was confirmed by fluorescence experiments (1.3ϫ103 –1)
NMR titration results.
which allowed us to determine the binding constants for the
The voltammogram of the fullerene crown ether 21 double complex [(14-2H·2PF6)·(21)2] as well as that for
shows three quasireversible reduction waves, which corre- [(19-H·PF6)·(21)] which resulted to be 1.4ϫ104 –1 and
spond to the first three reduction steps of the fullerene moi- 8.6ϫ102 –1 respectively.
ety. As expected, these reduction potentials appear at more
negative values than those of C60 due to the saturation of a plexation, UV/Vis and CV measurements revealed negligi-
double bond in the fullerene skeleton.[30]
ble electronic communication between the donor (exTTF)
Although ESI-MS evidenced the supramolecular com-
Upon addition of the exTTF ammonium salts, neither and acceptor (C60) moieties in the ground state. The redox
these waves nor the oxidation values of the exTTFs changed potential values of the exTTF units in the complexes ap-
5032
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 5027–5037

Supramolecular Threaded Complexes
373, 256 nm. A solution of this exTTF derivative (135 mg,
0.3 mmol) in THF/MeOH (1:1, 20 mL) and K2CO3 (40 mg,
0.3 mmol) was stirred at room temperature for 6 h. The mixture
was then extracted with CH2Cl2 (3ϫ25 mL), and the combined
organic layers were washed with water (2ϫ50 mL) and dried with
MgSO4. The residue was purified by flash chromatography on silica
gel using hexane/CH2Cl2 (3:1) as the eluent to give 8 (114 mg,
100%) as a yellow solid. 1H NMR (200 MHz, CDCl3): δ = 7.82 (d,
J = 1.6 Hz, 1 H), 7.72–7.64 (m, 3 H), 7.41 (dd, J = 8.0, 1.6 Hz, 1
H), 7.32–7.28 (m, 2 H), 6.33–6.32 (m, 4 H), 3.03 (s, 1 H) ppm. 13C
NMR (75 MHz, CDCl3): δ = 135.02, 129.4, 128.3, 126.0, 124.8,
119.2, 117.2, 117.1, 83.7, 77.1 ppm. MS (EI): m/z = 404 (M+). IR
peared slightly anodically shifted in comparison with the
neutral amines, probably due to the presence of the positive
charge in the complex, thus hindering the generation of new
charges in the oxidation process.
Finally, the quenching of the fluorescence observed upon
adding the ammonium salt of exTTFs to the crown ether
connected to the fullerene (21) suggest an electron transfer
from the donor (exTTF) to the acceptor (C60) unit, thus
mimicking the photosynthetic process. A thorough photo-
physical study is currently under investigation.
(KBr): ν
= 3255, 2122, 1546, 1406, 1280, 1247, 1004, 925, 856,
˜
max
655, 642 cm–1. UV (CH2Cl2): λmax = 436, 371, 246 nm.
Experimental Section
N-Benzyl-N-(4-iodobenzyl)amine (7): To a stirred solution of 4-
iodobenzaldehyde (746 mg, 5 mmol) and benzylamine (536 mg,
5 mmol) in methanol/acetic acid 99:1 (60 mL), sodium cyano-
borohydride (471 mg, 7.5 mmol) was added in portions over
30 min. The resulting mixture was stirred at room temperature for
20 h, and then poured into NaHCO3 solution (250 mL). The aque-
ous layer was then extracted with ethyl acetate (3ϫ50 mL), and
the combined organic extracts were washed with brine (3ϫ50 mL)
and dried with Na2SO4. The solvent was removed under reduced
pressure, and the product was purified by chromatography on a
silica gel column using hexane/ethyl acetate (1:1) as the eluent, giv-
General: All solvents were dried and distilled according to standard
procedures. Reagents were used as purchased. All air-sensitive reac-
tions were carried out under argon atmosphere. Flash chromatog-
raphy was performed using silica gel (Merck, kieselgel 60, 230–
240 mesh or Scharlau 60, 230–240 mesh). Analytical thin layer
chromatography (TLC) was performed using aluminum-backed
Merck Kieselgel 60 F254 plates. Melting points were determined
on a Gallenkamp apparatus. NMR spectra were recorded with
Bruker AC-200, Bruker Avance 300 or Bruker AMX 500 spectrom-
eters at 298 K using partially deuterated solvents as internal stan-
dards. Coupling constants (J) are denoted in Hz and chemical
shifts (δ) in ppm. Multiplicities are denoted as follows: s = singlet,
d = doublet, m = multiplet; br. = broad. FT-IR spectra were re-
corded with a Perkin–Elmer 781 or Nicolet–Magna IR 5550 spec-
trometers. UV/Vis spectra were recorded with a Varian Cary 50
spectrophotometer. Mass spectra were recorded with an HP 5989A
spectrometer or a Bruker Reflex III spectrometer with a nitrogen
laser operating at 337 nm. Cyclic voltammetry was performed using
an Autolab PGStat 30. These measurements were made in a
double-walled cell (Metrohm EA 876–20). A glassy carbon working
electrode (Metrohm 6.0804.010) was used after being polished with
alumina (0.3 µ) for 1 min, and platinum wire was used as the
counter electrode. A Ag/Ag+ electrode was used as a reference. Tet-
rabutylammonium hexafluorophosphate (0.1 ) was used as the
supporting electrolyte, and dry dichloromethane/acetonitrile, 1:1
was used as the solvent. The samples were purged with argon prior
to measurement. The scan rate was 100 mV/s.
1
ing 7 as an oil (297 mg, 92%). H NMR (300 MHz, CDCl3): δ =
7.58 (d, J = 8.1 Hz, 2 H), 7.29–7.16 (m, 5 H), 7.02 (d, J = 8.1 Hz,
2 H), 3.71 (s, 2 H), 3.66 (s, 2 H), 1.99 (s, 1 H, NH) ppm. MS (ESI):
m/z = 322 (M+). IR: ν
= 3400, 2922, 1550, 1253, 1217, 1009,
˜
max
630 cm–1. UV (CH2Cl2): λmax = 276, 234 nm.
N-Benzyl-N-(4-{[9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydro-
anthracen-2-yl]ethynyl}benzyl)amine (8): To a solution of the depro-
tected alkyne 6 (444 mg, 1.1 mmol) in dry THF (50 mL), benzyl(4-
iodobenzyl)amine 7 (323 mg, 1 mmol), Pd(PPh3)4 (58 mg,
0.05 mmol), CuI (10 mg, 0.05 mmol) and distilled diisopropylamine
(1 mL) were added. The solution was refluxed under argon for 20 h.
After cooling to room temperature, ethyl acetate (50 mL) was
added to the solution. The organic layer was washed sequentially
with a saturated NH4Cl solution (50 mL), water (2ϫ50 mL) and
brine (2ϫ50 mL), and then dried with MgSO4. The solvent was
removed under reduced pressure, and the crude product was puri-
fied by silica gel flash chromatography with dichloromethane as
the eluent, providing 8 as a yellow solid (287 mg, 48%). M.p. 161–
163 °C. 1H NMR (200 MHz, CDCl3): δ = 7.84 (d, J = 1.2 Hz, 2
H), 7.73–7.63 (m, 4 H), 7.53–7.28 (m, 8 H), 7.16 (d, J = 8.4 Hz, 2
H), 6.33 (s, 2 H), 6.32 (s, 2 H), 3.54 (s, 2 H), 3.49 (s, 2 H) ppm.
13C NMR (125 MHz, CDCl3): δ = 137.18, 137.11, 135.94, 135.71,
135.65, 132.62, 132.57, 132.16, 129.54, 129.09, 129.00, 128.94,
128.89, 128.86, 128.65, 128.60, 128.54, 128.29, 127.62, 127.49,
127.45, 126.52, 126.50, 125.43, 125.35, 122.39, 122.12, 121.69,
121.12, 117.74, 117.71, 117.66, 117.62, 90.09, 53.50 ppm. HRMS
(MALDI-TOF): calcd. for [C36H25NS4]+ 599.0864; found
2-Ethynyl-9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene (6):
To a solution of the iodo derivative 5 (1.35 g, 2.7 mmol) in dry
THF (50 mL), trimethylsilylacetylene (288 mg, 2.9 mmol),
Pd(PPh3)4 (154 mg, 0.13 mmol), CuI (25 mg, 0.13 mmol) and diiso-
propylamine (816 mg, 8.0 mmol) were added. The reaction was re-
fluxed under argon for 12 h. After cooling to room temperature,
ethyl acetate (50 mL) was added to the solution. The organic layer
was washed sequentially with a saturated NH4Cl solution (50 mL),
water (2ϫ50 mL) and brine (2ϫ50 mL), and then dried with
MgSO4. The solvent was removed under reduced pressure, and the
crude product was purified by silica gel flash chromatography using
hexane/dichloromethane (3:1) as the eluent, providing the TMS
protected alkynyl TTF derivative as a red solid in 54% yield
599.0892. IR (KBr): ν
= 3437, 1545, 1454, 1406, 802, 756, 650,
˜
max
640 cm–1. UV (CH2Cl2): λmax = 441, 376, 309, 272 nm.
1
(686 mg). H NMR (200 MHz, CDCl3): δ = 7.76 (d, J = 1.5 Hz, 1
Ammonium Salt 8-H·PF6: Aqueous HCl (3 ) was added with stir-
ring to a solution of compound 8 (100 mg, 0.17 mmol) in MeOH/
H), 7.70–7.63 (m, 2 H), 7.59 (br. s, 1 H), 7.37 (dd, J = 8.1, 1.5 Hz,
1 H), 7.32–7.23 (m, 2 H), 6.28 (s, 4 H), 0.27 (s, 9 H) ppm. 13C THF (1:1, 60 mL) until the pH was just less than 1. After stirring
NMR (75 MHz, CDCl3): δ = 136.7, 136.6, 135.5, 135.4, 135.2,
129.5, 128.2, 126.1, 126.0, 125.0, 124.9, 124.8, 121.7, 121.2, 120.5,
117.3, 117.1, 105.4, 94.3, 0.04 ppm. m/z (EI) = 476 (M+). IR (KBr):
for 3 h, the resulting suspension was concentrated in vacuo. The
residue was dissolved in MeNO2 (200 mL), and saturated aqueous
NH4PF6 (50 mL) was added. The phases were partitioned, and the
organic phase was washed with sat. aqueous NH4PF6 (50 mL) and
water (4ϫ100 mL), dried with MgSO4, and filtered. The solvent
ν
= 2343, 1598, 1406, 1280, 1220, 1159, 1093, 1004, 925, 800,
˜
max
655, 619, 567, 505, 459, 445, 434 cm–1. UV (CH2Cl2): λmax = 437,
Eur. J. Org. Chem. 2007, 5027–5037
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5033

N. Martín, D. M. Guldi, et al.
FULL PAPER
was removed under reduced pressure to give the ammonium salt as
a red solid (700 mg, 94%). M.p. 296 °C (dec.). 1H NMR (300 MHz,
CD3CN): δ = 9.55 (s, 2 H), 7.90–7.24 (m, 20 H), 4.19–4.14 (m, 4
benzyl)amine (14): To a solution of the deprotected alkyne 13
(428 mg, 1 mmol) in dry THF (50 mL), the iodo derivative 7
(1.22 g, 3 mmol), Pd(PPh3)4 (115 mg, 0.1 mmol), CuI (19 mg,
0.1 mmol) and distilled diisopropylamine (1 mL) were added. The
solution was refluxed under argon for 24 h. After warming to room
temperature, ethyl acetate (50 mL) was added to the solution. The
organic layer was washed sequentially with a saturated NH4Cl solu-
tion (50 mL), water (2ϫ50 mL) and brine (2ϫ50 mL), and then
dried with MgSO4. The solvent was removed under reduced pres-
sure, and the crude product was purified by silica gel flash
chromatography using ethyl acetate as the eluent, providing 14 as
an orange solid (229 mg, 28 %). M.p. 260 °C (dec.). 1H NMR
(200 MHz, CDCl3): δ = 7.85 (d, J = 1.2 Hz, 2 H), 7.73–7.63 (m, 4
H), 7.55–7.43 (m, 8 H), 7.37–7.29 (m, 12 H), 6.34 (s, 4 H), 3.82 (m,
8 H) ppm. 13C NMR (125 MHz, CD3CN): δ = 140.11, 137.53,
136.53, 136.37, 132.68, 130.76, 130.41, 130.12, 130.01, 129.59,
129.24, 129.09, 128.58, 126.30, 123.80, 121.52, 120.74, 118.87,
118.67, 117.94, 90.56, 90.29, 52.79, 52.39 ppm. HRMS (MALDI-
TOF): calcd. for [C52H38N2S4]+ 818.1912; found 818.1865. IR
H) ppm. m/z (ESI) = 599 (M – HPF )+. IR (KBr): ν
= 3436,
˜
6
max
2926, 2854, 2341, 1635, 1402, 833, 559 cm–1. UV (CD3CN): λmax
=
423, 379, 276, 270 nm.
2,6-Diiodo-9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene
(11): n-Butyllithium (BuLi) (1.6  in hexane; 0.7 mL, 1.1 mmol)
was added via syringe into a stirred solution of the phosphonate
10[24] (212 mg, 1 mmol) in dry THF (100 mL) at –78 °C under ar-
gon. After 30 min at –78 °C, anthraquinone 9 (115 mg, 0.25 mmol),
dissolved in dry THF (100 mL), was added via syringe into the
solution of phosphonate carbanion. The mixture was stirred for
1 h at –78 °C, and then warmed to 20 °C overnight. After evapora-
tion of the solvent, the residue was diluted with water (100 mL)
and extracted with dichloromethane (3ϫ75 mL). The combined
organic extracts were sequentially washed with water (2ϫ75 mL),
brine (1ϫ75 mL) and dried with MgSO4. After removing the sol-
vent in vacuo, the residue was purified by column chromatography
on silica gel with hexane/dichloromethane (9:1) as the eluent to
afford 11 as a yellow solid (131 mg, 82%). M.p. 252–254 °C. 1H
NMR (200 MHz, CDCl3): δ = 7.99 (d, J = 1.7 Hz, 2 H), 7.60 (dd,
J = 8.1, 1.7 Hz, 2 H), 7.41 (d, J = 8.1 Hz, 2 H), 6.35 (s, 4 H) ppm.
13C NMR (50 MHz, CDCl3): δ = 146.1, 142.2, 139.7, 139.2, 134.1,
132.0, 128.7, 127.8, 127.2, 119.5, 117.1, 114.2 ppm. MS (EI): m/z
(KBr): νmax = 3437, 2924, 2852, 1630, 1500, 1458, 1400, 1120, 698,
˜
542 cm–1. UV (CH3CN): λmax = 448, 385, 311, 246 nm.
Ammonium Salt 14-2H·2PF6: Aqueous HCl (3 ) was added with
stirring to a solution of compound 14 (100 mg, 0.12 mmol) in
MeOH/THF, 1:1 (80 mL) until the pH was below 1. After stirring
for 3 h, the resulting suspension was concentrated in vacuo. The
residue was dissolved in MeNO2 (250 mL), and saturated aqueous
NH4PF6 (75 mL) was added. The phases were partitioned, and the
organic phase washed with sat. aqueous NH4PF6 (75 mL) and
water (4ϫ100 mL), dried with MgSO4 and filtered. The solvent
was removed under reduced pressure to give the ammonium salt as
an orange solid (121 mg, 90%). 1H NMR (300 MHz, CD3COCD3):
δ = 9.95 (s, 4 H), 8.16 (s, 2 H), 8.03–7.99 (m, 2 H), 7.83–7.38 (m,
24 H), 4.64–4.53 (m, 8 H) ppm. MS (ESI): m/z = 818 (M –
= 632 (M+), 506 (M+ – I), 380 (M+ – 2I). IR (KBr): ν
= 2924,
˜
max
2852, 2183, 1545, 1516, 1452, 1394, 756, 646, 623, 501 cm–1. UV
(CH2Cl2): λmax = 430, 366, 238 nm.
2,6-Bis[(trimethylsilyl)ethynyl]-9,10-bis(1,3-dithiol-2-ylidene)-9,10-di-
hydroanthracene (12): To a solution of diiodo exTTF 11 (942 mg,
1.49 mmol) in Et3N (40 mL), Pd(OAc)2 (33.4 mg, 0.15 mmol), PPh3
(78.2 mg, 0.3 mmol) and trimethylsilylacetylene (0.64 mL,
4.48 mmol) were added under argon. The reaction was heated at
90 °C for 26 h. The mixture was diluted with ethyl acetate (50 mL),
washed with brine (3ϫ50 mL) and dried with MgSO4. The solvent
was removed in vacuo, and the resulting residue was purified by
flash chromatography on silica gel using hexane/ethyl acetate (9:1)
as the eluent to afford 12 (429 mg, 75%) as a yellow solid. M.p.
179–181 °C. 1H NMR (300 MHz, CDCl3): δ = 7.76 (d, J = 1.5 Hz,
2 H), 7.65 (d, J = 8.2 Hz, 2 H), 7.38 (dd, J = 8.2, 1.5 Hz, 2 H),
6.31 (s, 4 H), 0.27 (s, 18 H) ppm. 13C NMR (75 MHz, CDCl3): δ
= 136.7, 136.6, 135.5, 135.4, 135.2, 129.5, 128.2, 126.1, 126.0, 124.5,
124.9, 124.8, 121.7, 121.2, 120.5, 117.3, 117.2, 117.1, 105.4, 94.3,
2HPF )+. IR (KBr): ν
= 3437, 2926, 2361, 2343, 2208, 1618,
˜
6
max
1458, 843, 559 cm–1. UV (CD3CN): λmax = 425, 329, 239, 198 nm.
[9,10-Bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracen-2-yl]methyl 4-
[(Benzylamino)methyl]benzoate (16): To a stirred solution of alde-
hyde 15[11h] (70 mg, 0.13 mmol) and benzylamine (14 mg,
0.13 mmol) in methanol/acid acetic 99:1 (20 mL), sodium cyano-
borohydride (12.2 mg, 1.5 mmol) was added in portions over
30 min. The resulting mixture was stirred at room temperature for
4 h and poured into a NaHCO3 solution (25 mL). The aqueous
layer was then extracted with ethyl acetate (50 mL), and the com-
bined organic extracts were washed with brine (40 mL) and dried
with Na2SO4. The solvent was removed under reduced pressure,
and the product was purified by chromatography on a silica gel
column with dichloromethane/ethyl acetate (7:3) as the eluent, giv-
ing 16 as a yellow solid (63 mg, 62%). M.p. Ͼ 300 °C (dec.). 1H
NMR (200 MHz, CDCl3): δ = 8.02 (d, J = 8.1 Hz, 2 H), 7.73–7.61
(m, 4 H), 7.38–7.19 (m, 10 H), 6.22 (s, 2 H), 6.20 (s, 2 H), 5.35 (s,
2 H), 3.80 (s, 2 H), 3.74 (s, 2 H) ppm. 13C NMR (50 MHz, CDCl3):
δ = 166.3, 144.5, 135.7, 135.3, 135.2, 133.7, 130.0, 128.5, 128.4,
128.3, 127.4, 126.0, 125.6, 125.1, 125.0, 124.9, 124.6, 121.8, 121.7,
117.2, 117.1, 66.5, 52.7, 52.6 ppm. HRMS (MALDI-TOF): calcd.
0.1 ppm. MS (EI): m/z = 572 (M+). IR (KBr): ν
= 2343, 1598,
˜
max
1406, 1280, 1220, 1159, 1093, 1004, 925, 800, 655, 619, 567 cm–1.
UV (CH2Cl2): λmax = 450, 382, 273 nm.
2,6-Diethynyl-9,10-bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracene
(13): To a solution of 12 (543 mg, 0.95 mmol) in THF/MeOH, 1:1
(30 mL), K2CO3 (272 mg, 1.97 mmol) was added. The reaction was
stirred at room temperature for 6 h. The solution was extracted
with CH2Cl2 (3ϫ25 mL) and the combined organic layers were
washed with water (2ϫ50 mL) and dried with MgSO4. The residue
was purified by flash chromatography on silica gel using hexane/
CH2Cl2 (2:1) as the eluent to give 13 (407 mg, 100%) as a yellow
solid. M.p. 201 °C (dec.). 1H NMR (200 MHz, CDCl3): δ = 7.80
(d, J = 1.8 Hz, 2 H), 7.64 (d, J = 8.0 Hz, 2 H), 7.40 (dd, J = 8.0,
1.8 Hz, 2 H), 6.31 (s, 4 H), 3.11 (s, 2 H) ppm. 13C NMR (50 MHz,
CDCl3): δ = 135.0, 129.4, 128.3, 125.9, 124.8, 119.2, 117.2, 117.1,
for [C36H27NO2S4]+ 633.0919; found 633.0903. IR (KBr): ν
=
˜
max
3447, 1716, 1653, 1628, 1543, 1508, 1269, 1103, 754, 646 cm–1. UV
(CH2Cl2): λmax = 431, 366, 240 nm.
83.7, 77.1 ppm. MS (EI) m/z = 428 (M+). IR (KBr): ν
= 3255,
˜
max
Ammonium Salt 16-H·PF6: Aqueous HCl (3 ) was added with stir-
ring to a solution of compound 16 (100 mg, 0.16 mmol) in MeOH/
THF, 1:1 (60 mL) until the pH was just less than 1. After stirring
for 3 h, the resulting suspension was concentrated in vacuo. The
residue was dissolved in MeNO2 (200 mL), and saturated aqueous
2122, 1546, 1406, 1280, 1247, 1004, 925, 856, 655, 642 cm–1. UV
(CH2Cl2): λmax = 449, 381, 262 nm.
N-Benzyl-N-(4-{[6-({4-[(benzylamino)methyl]phenyl}ethynyl)-9,10-
bis(1,3-dithiol-2-ylidene)-9,10-dihydroanthracen-2-yl]ethynyl}-
5034
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 5027–5037

Supramolecular Threaded Complexes
NH4PF6 (50 mL) was added. The phases were partitioned, and the
organic phase washed with sat. aqueous NH4PF6 (50 mL) and
water (4ϫ100 mL), dried with MgSO4 and filtered. The solvent
was removed under reduced pressure to give the ammonium salt
as an orange solid (118 mg, 95%). M.p. 216 °C (dec.) 1H NMR
(300 MHz, CD3CN): δ = 9.52 (s, 1 H), 9.51 (s, 1 H), 8.04 (d, J =
8.2 Hz, 2 H), 7.86–7.70 (m, 9 H), 7.60 (d, J = 8.2 Hz, 2 H), 7.49–
was removed under reduced pressure to give the ammonium salt
as an orange solid (122 mg, 93%). M.p. 211 °C (dec.). 1H NMR
(300 MHz, CD3COCD3): δ = 8.17 (d, J = 8.0 Hz, 2 H), 8.04–8.01
(m, 4 H), 7.83–7.79 (m, 6 H), 7.55–7.54 (m, 2 H), 7.44–7.42 (m, 3
H), 6.15 (s, 2 H), 4.59 (s, 2 H), 4.47 (s, 2 H), 3.33 (s, 3 H), 3.13
(s, 6 H) ppm. HRMS (MALDI-TOF): calcd. for [C39H33NO2S4]+
675.1389; found 675.1406. IR (KBr): ν
= 3439, 2924, 2852,
˜
max
7.46 (m, 7 H), 5.51 (s, 2 H), 4.33–4.24 (m, 4 H) ppm. MS (ESI): 1628, 1387, 1099, 839, 557 cm–1. UV (CH3CN): λmax = 431, 396,
m/z = 633 (M – HPF )+. IR (KBr): νmax = 3437, 1716, 1635, 1431, 373, 313, 259 nm.
˜
6
1275, 1124, 1084, 868, 845, 744, 559, 484 cm–1. UV (CH3CN): λmax
DB24C8 Fullerene 21: A solution of C60 (106 mg, 0.15 mmol), (2-
= 470, 399, 374, 264 nm.
formyl)dibenzo[24]crown-8 (20)[26] (70 mg, 0.15 mmol) and sarco-
sine (65 mg, 0.73) in chlorobenzene (50 mL) was refluxed for 16 h.
The solvent was removed under reduced pressure, and the crude
material was carefully purified by chromatography on a silica gel
column using toluene/ethyl acetate (1:1) as the eluent. Further puri-
fication was accomplished by repetitive precipitation and centrifu-
gation by using cyclohexane as solvent (81 mg, 44%). M.p. 241–
243 °C. 1H NMR (300 MHz, CDCl3): δ = 7.42–7.37 (m, 2 H), 6.93–
6.83 (m, 5 H), 4.98 (d, J = 9.4 Hz, 1 H), 4.86 (s, 1 H), 4.24 (d, J =
9.4 Hz, 1 H), 4.17–4.13 (m, 8 H), 3.93–3.91 (m, 8 H), 3.84–3.82 (m,
8 H), 2.81 (s, 3 H) ppm. 13C NMR (125 MHz, CDCl3): δ = 149.35,
147.73, 147.71, 147.24, 146.88, 146.74, 146.68, 146.63, 146.57,
146.55, 146.51, 146.37, 146.34, 146.19, 145.96, 145.94, 145.90,
145.76, 145.72, 145.69, 145.65, 145.57, 145.11, 145.05, 144.80,
143.57, 143.40, 143.10, 143.01, 142.99, 142.96, 142.64, 142.58,
142.55, 142.45, 142.31, 142.25, 142.10, 141.98, 140.58, 140.53,
140.26, 140.10, 136.95, 136.14, 121.85, 121.83, 114.49, 83.72, 71.78,
71.75, 71.69, 71.66, 70.35, 70.30, 70.17, 69.89, 69.84, 69.78,
69.63, 69.36, 40.42 ppm. HRMS (MALDI-TOF): calcd. for
[C87H38NO8]+ 1224.2592 (M++H); found 1224,2611. IR (KBr):
{(2Z)-2-[10-(4,5-Dimethyl-1,3-dithiol-2-ylidene)anthracen-9(10H)-
ylidene]-5-methyl-1,3-dithiol-4-yl}methyl 4-Formylbenzoate (18): To
a suspension of 4-formylbenzoic acid (83 mg, 0.55 mmol) in
CH2Cl2 (10 mL), DCC (126 mg, 0.61 mmol) and DMAP (74 mg,
0.61 mmol) were added. The mixture was stirred for 20 min at room
temperature, and then a solution of the hydroxy derivative 17
(250 mg, 0.55 mmol) in CH2Cl2 (10 mL) was added. After stirring
for 20 h, the solvent was removed in vacuo yielding a residue, which
was purified by column chromatography (SiO2, hexane/ethyl ace-
tate, 8:2). Compound 18 was obtained as a yellow solid (161 mg,
50%). M.p. 185 °C. 1H NMR (300 MHz, CDCl3): δ = 10.1 (s, 1
H), 8.20 (d, J = 8.3 Hz, 2 H), 7.95 (d, J = 8.3 Hz, 2 H), 7.68–7.59
(m, 4 H), 7.32–7.26 (m, 4 H), 5.10 (d, JAB = 12.9 Hz, 1 H), 4.99
(d, JAB = 12.9 Hz, 1 H), 2.12 (s, 3 H), 1.92 (s, 6 H) ppm. 13C NMR
(75 MHz, CDCl3): δ = 192.1, 165.5, 139.7, 135.6, 135.3, 134.9,
133.8, 131.7, 130.9, 130.8, 130.3, 129.9, 126.4, 126.3, 126.2, 126.1,
125.8, 125.7, 125.6, 125.2, 123.0, 121.2, 120.4, 59.3, 13.9, 13.5 ppm.
MS (ESI): m/z = 584 (M+). IR (KBr): ν
= 2920, 2850, 1726,
˜
max
1707, 1522, 1444, 1267, 1201, 1097, 756 cm–1. UV (CHCl3): λmax
=
ν
max = 3010, 2925, 2856, 2779, 2360, 1504, 1461, 1419, 1257, 1215,
˜
436, 367, 306, 254, 239 nm.
1128, 756 cm–1. UV (CH2Cl2): λmax = 432, 309, 256 nm.
{(2Z)-2-[10-(4,5-Dimethyl-1,3-dithiol-2-ylidene)anthracen-
9(10H)-ylidene]-5-methyl-1,3-dithiol-4-yl}methyl 4-[(Benzylamino)-
methyl]benzoate (19): To a stirred solution of aldehyde 18 (76 mg,
0.13 mmol) and benzylamine (14 mg, 0.13 mmol) in methanol/acid
acetic 99:1 (20 mL), sodium cyanoborohydride (12.2 mg, 1.5 mmol)
was added in portions over 30 min. The resulting mixture was
stirred at room temperature for 14 h, and then poured into a
NaHCO3 solution (25 mL). The aqueous layer was then extracted
with ethyl acetate (50 mL), and the combined organic extracts were
washed with brine (40 mL) and dried with Na2SO4. The solvent
was removed under reduced pressure, and the product was purified
by chromatography on a silica gel column using dichloromethane/
ethyl acetate (9:1) as the eluent, giving 19 as a yellow solid (34 mg,
38%). M.p. 130–132 °C. 1H NMR (500 MHz, CD3COCD3): δ =
8.00–7.96 (m, 2 H), 7.67–7.63 (m, 4 H), 7.57–7.53 (m, 2 H), 7.41–
7.39 (m, 2 H), 7.37–7.31 (m, 6 H), 7.27–7.23 (m, 2 H) ppm. 13C
NMR (125 MHz, CD3COCD3): δ = 205.62, 165.81, 135.68, 135.66,
135.45, 135.43, 130.10, 130.07, 129.87, 129.84, 129.33, 128.55,
128.53, 128.48, 127.04, 126.98, 126.50, 126.47, 126.31, 126.28,
125.73, 125.71, 125.68, 125.60, 122.39, 121.50, 121.19, 121.12,
58.46, 57.01, 55.21, 53.07, 52.63, 12.90, 12.46 ppm. MS (EI): m/z
This work has been supported by the Spanish Ministerio de Educa-
ción y Ciencia (MEC), through the project CTQ2005-02609/BQU
and by the Comunidad de Madrid (P-PPQ-000225-0505), The
European Union (TRN network WONDERFULL), the Deutsche
Forschung-gemeinschaft (SFB 583), FCI, and the Office of Basic
Energy Sciences of the U.S. Department of Energy. J. S. is indebted
to MEC for a research grant. We thank Dr. E. M. Pérez for helpful
discussions and Dr. C. Raposo (Universidad de Salamanca) for
generously providing the software for binding constant analysis.
Acknowledgments
[1] a) H. Kurreck, M. Huber, Angew. Chem. Int. Ed. Engl. 1995,
34, 849; b) T. J. Meyer, Acc. Chem. Res. 1989, 22, 163; c) M. R.
Wasielewski, Chem. Rev. 1992, 92, 435; d) D. Gust, T. A.
Moore, A. L. Moore, Acc. Chem. Res. 2001, 34, 40; e) D.
Holten, D. F. Bocian, J. S. Lindsey, Acc. Chem. Res. 2002, 35,
57; f) D. M. Adams, L. Brus, E. D. Chidsey, S. Creager, C.
Creutz, C. R. Kagan, P. V. Kamat, M. Lieberman, S. Linsey,
R. A. Marcus, R. M. Metzger, M. E. Michel-Beyerle, J. R.
Miller, M. D. Newton, D. R. Rolison, O. Sankey, K. S.
Schanze, J. Yardley, X. Zhu, J. Phys. Chem. B 2003, 107, 6668;
g) N. Armaroli, Photochem. Photobiol. Sci. 2003, 2, 73; h) H.
Imahori, Y. Mori, Y. Matano, J. Photochem. Photobiol. 2003,
C4, 51.
= 675 (M+). IR (KBr): ν
= 3447, 1716, 1653, 1628, 1543, 1508,
˜
max
1269, 1103, 754, 646 cm–1. UV (CH2Cl2): λmax = 431, 366, 240 nm.
Ammonium Salt 19-H·PF6: Aqueous HCl (3 ) was added with stir-
ring to a solution of compound 19 (108 mg, 0.16 mmol) in MeOH/
THF (1:1, 60 mL) until the pH was just less than 1. After stirring
for 3 h, the resulting suspension was concentrated in vacuo. The
residue was dissolved in MeNO2 (200 mL), and saturated aqueous
NH4PF6 (50 mL) was added. The phases were partitioned, and the
organic phase was washed with sat. aqueous NH4PF6 (50 mL) and
water (4ϫ100 mL), dried with MgSO4 and filtered. The solvent
[2] Energy Harvesting Materials (Ed.: D. I. Andrew), World Scien-
tific Publishing Co., Singapore, 2005.
[3] a) A. Hirsch, The Chemistry of Fullerenes, Thieme, New York,
1994; b) F. Diederich, C. Thilgen, Science 1996, 271, 317; c)
Fullerenes and Related Structures (Ed.: A. Hirsch), Topics in
Eur. J. Org. Chem. 2007, 5027–5037
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5035

N. Martín, D. M. Guldi, et al.
FULL PAPER
Current Chemistry, 1999, vol. 199, Springer, Berlin; d) Fuller-
enes: From Synthesis to Optoelectronic Properties, (Eds: D. M.
Guldi, N. Martín), Kluwer Academic Publishers, Dordrecht,
2002; e) Special issue on Functionalized Fullerene Materials:
M. Prato, N. Martín (Eds.), J. Mater. Chem. 2002, 12, 1931–
2159; f) D. M. Guldi, M. Prato, Acc. Chem. Res. 2000, 33, 696;
g) L. Echegoyen, L. E. Echegoyen, Acc. Chem. Res. 1998, 31,
593; h) D. M. Guldi, Chem. Commun. 2000, 321; i) N. Martín,
L. Sánchez, B. Illescas, I. Pérez, Chem. Rev. 1998, 98, 2527–
2547; j) N. Martín, Chem. Commun. 2006, 2093–2104.
For a review, see: a) D. M. Guldi, Chem. Soc. Rev. 2002, 31,
22; b) H. Imahori, J. Phys. Chem. B 2004, 108, 6130.
a) M. Fujitsuka, N. Tsuboya, R. Hamasaki, M. Ito, S. Onod-
era, O. Ito, Y. Yamamoto, J. Phys. Chem. A 2003, 107, 1452;
b) D. M. Guldi, C. Luo, N. A. Kotov, T. Da Ros, S. Bosi, M.
Prato, J. Phys. Chem. A 2003, 107, 7293; c) D. M. Guldi, G.
Scorrano, M. Prato, J. Am. Chem. Soc. 1997, 109, 974.
a) J. F. Nierengarten, N. Armaroli, G. Accorsi, Y. Rio, J. F.
Eckert, Chem. Eur. J. 2003, 9, 36; b) D. M. Guldi, M. Maggini,
E. Menna, G. Scorrano, P. Ceroni, M. Marcaccio, F. Paolucci,
S. Roffia, Chem. Eur. J. 2001, 7, 1597.
S. Smirnov, P. A. Lidell, I. V. Vlassiouk, A. Teslja, D. Kuc-
iauskas, C. L. Braun, A. L. Moore, T. A. Moore, D. Gust, J.
Phys. Chem. A 2003, 107, 7567.
a) K. G. Thomas, V. Biju, D. M. Guldi, P. V. Kamat, M. V.
George, J. Phys. Chem. B 1999, 103, 8864; b) R. M. Williams,
J. M. Zwier, J. W. Verhoeven, J. Am. Chem. Soc. 1995, 117,
4093.
a) P. A. van Hal, S. C. J. Meskers, R. A. J. Janssen, Appl. Phys.
A 2004, 79, 41; b) D. M. Guldi, C. Luo, R. Gómez, A. Swartz,
J. L. Segura, N. Martín, C. Brabec, N. S. Sariciftci, J. Org.
Chem. 2002, 67, 1141; c) D. M. Guldi, A. Swartz, Ch. Luo, R.
Gómez, J. L. Segura, N. Martín, J. Am. Chem. Soc. 2002, 124,
10875–10886; d) C. M. Atienza, G. Fernández, L. Sánchez, N.
Martín, I. Sá Dantas, M. M. Wienk, R. A. J. Janssen, G. M. A.
Rahman, D. M. Guldi, Chem. Commun. 2006, 514–516; e) For
a recent review, see: J. L. Segura, N. Martín, D. M. Guldi,
Chem. Soc. Rev. 2005, 34, 31.
de la Garza, A. L. Moore, T. A. Moore, D. Gust, J. Mater.
Chem. 2002, 12, 2100.
[13]
a) H. Sasabe, N. Kiara, Y. Furusho, K. Mizuno, A. Ogawa, T.
Takata, Org. Lett. 2004, 6, 3957; b) J. L. Sessler, J. Jayawickra-
marajah, A. Gouloumis, T. Torres, D. M. Guldi, S. Maldon-
ado, K. J. Stevenson, Chem. Commun. 2005, 1892–1894; c) U.
Hahn, M. Elhabiri, A. Trabolsi, H. Herschbach, E. Leize, A.
Van Dorsselaer, A.-M. Albrecht-Gary, J.-F. Nierengarten, An-
gew. Chem. Int. Ed. 2005, 44, 5338–5341; d) M. Segura, L.
Sánchez, J. de Mendoza, N. Martín, D. M. Guldi, J. Am.
Chem. Soc. 2003, 125, 15093; e) D. M. Guldi, N. Martín, J.
Mater. Chem. 2002, 12, 1978–1992; For a recent review on hy-
drogen-bonding motifs in fullerene chemistry, see: ; f) L.
Sánchez, N. Martín, D. M. Guldi, Angew. Chem. Int. Ed. 2005,
44, 2–10; g) For a Special Issue on Supramolecular Chemistry
of Fullerenes, see: N. Martín, J.-F. Nierengarten, Tetrahedron
2006, 62, 1905–2132.
a) M. B. Nielsen, C. Lomholt, J. Becher, Chem. Soc. Rev. 2000,
29, 153–164; b) J. L. Segura, N. Martín, Angew. Chem. Int. Ed.
2001, 40, 1372–1409; c) J. O. Jeppesen, M. B. Nielsen, J. Becher,
Chem. Rev. 2004, 104, 5115–5132; d) TTF Chemistry: Funda-
mentals and Applications of Tetrathiafulvalene (Eds.: J. Yamada,
T. Sugimoto), Kodansha-Springer, Tokyo, 2004.
[4]
[5]
[14]
[15]
[6]
[7]
[8]
M. R. Bryce, A. S. Batsanov, T. Finn, T. K. Hansen, A. J.
Moore, J. A. K. Howard, M. Kamenjicki, I. K. Lednev, S. A.
Asher, Eur. J. Org. Chem. 2001, 933–940.
E. M. Pérez, L. Sánchez, G. Fernández, N. Martín, J. Am.
Chem. Soc. 2006, 128, 7172–7173.
M. C. Díaz, B. M. Illescas, N. Martín, J. F. Stoddart, M. A.
Canales, J. Jiménez-Barbero, G. Sarova, D. M. Guldi, Tetrahe-
dron 2006, 62, 1998–2002.
[16]
[17]
[9]
[18]
[19]
J.-M. Lehn in Supramolecular Chemistry, Concepts and Perspec-
tives, VCH, Weinheim, Germany, 1995.
a) J.-F. Nierengarten, U. Hahn, T. M. Figueira Duarte, F. Car-
dinali, N. Solladié, M. E. Walther, A. Van Dorsselaer, H.
Herschbach, E. Leize, A.-M. Albrecht-Gary, A. Trabolsi, M.
Elhabiri, C. R. Chim. 2006, 9, 1022–1030; b) N. Solladié, M. E.
Walther, H. Herschbach, E. Leize, A. Van Dorsselaer, T. M.
Figueira Duarte, J.-F. Nierengarten, Tetrahedron 2006, 62,
1979; c) M. Elhabiri, A. Trabolsi, F. Cardinali, U. Hahn, A.-
M. Albrecht-Gary, J.-F. Nierengarten, Chem. Eur. J. 2005, 11,
4793; d) N. Solladié, M. E. Walther, M. Gross, T. M. Fig-
ueira Duarte, C. Bourgogne, J.-F. Nierengarten, Chem. Com-
mun. 2003, 2412; e) D. I. Schuster, P. D. Jarowski, A. N.
Kirschner, S. R. Wilson, J. Mater. Chem. 2002, 12, 2041; f) N.
Armaroli, G. Marconi, L. Echegoyen, J.-P. Bourgeois, F. Died-
erich, Chem. Eur. J. 2000, 6, 1629.
[10]
[11]
M. A. Loi, H. Neugebauer, P. Denk, C. J. Brabec, N. S. Saric-
iftci, A. Gouloumis, P. Vázquez, T. Torres, J. Mater. Chem.
2003, 13, 700.
a) D. M. Guldi, S. González, N. Martín, A. Antón, J. Garín,
J. Orduna, J. Org. Chem. 2000, 65, 1978; b) N. Martín, L.
Sánchez, M. A. Herranz, D. M. Guldi, J. Phys. Chem. A 2000,
104, 46–48; c) N. Martín, L. Sánchez, D. M. Guldi, Chem.
Commun. 2000, 113; d) J. L. Segura, E. M. Priego, N. Martín,
C. P. Luo, D. M. Guldi, Org. Lett. 2000, 2, 4021; e) M. A. Her-
ranz, N. Martín, J. Ramey, D. M. Guldi, Chem. Commun. 2002,
2968; f) S. González, N. Martín, D. M. Guldi, J. Org. Chem.
2003, 68, 779–791; g) S. González, N. Martín, A. Swartz, D. M.
Guldi, Org. Lett. 2003, 5, 557; h) L. Sánchez, I. Pérez, N.
Martín, D. M. Guldi, Chem. Eur. J. 2003, 9, 2457; i) M. C.
Díaz, M. A. Herranz, B. M. Illescas, N. Martín, N. Godbert,
M. R. Bryce, C. Luo, A. Swartz, G. Anderson, D. M. Guldi, J.
Org. Chem. 2003, 68, 7711–7721; j) F. Giacalone, J. L. Segura,
N. Martín, D. M. Guldi, J. Am. Chem. Soc. 2004, 126, 5340; k)
L. Sánchez, M. Sierra, N. Martín, D. M. Guldi, M. W. Wienk,
R. A. J. Janssen, Org. Lett. 2005, 7, 1691; l) G. de la Torre, F.
Giacalone, J. L. Segura, N. Martín, D. M. Guldi, Chem. Eur.
J. 2005, 11, 1267–1280; m) F. Giacalone, N. Martín, J. Ramey,
D. M. Guldi, Chem. Eur. J. 2005, 11, 4819–4834; n) D. M.
Guldi, F. Giacalone, G. de la Torre, J. L. Segura, N. Martín,
Chem. Eur. J. 2005, 11, 7199–7210; o) S. Handa, F. Giacalone,
S. A. Haque, E. Palomares, N. Martín, J. R. Durrant, Chem.
Eur. J. 2005, 11, 7440–7447.
[20]
[21]
[22]
M. C. Díaz, B. M. Illescas, C. Seoane, N. Martín, J. Org. Chem.
2004, 69, 4492–4499.
T. Da Ros, M. Prato, F. Novello, M. Maggini, E. Banfi, J. Org.
Chem. 1996, 61, 9070–9072.
a) F. Diederich, L. Echegoyen, M. Gómez-López, R. Kessinger,
J. F. Stoddart, J. Chem. Soc. Perkin Trans. 2 1999, 1577–1586;
b) P. R. Ashton, J. Becher, M. C. T. Fyfe, M. B. Nielsen, J. F.
Stoddart, A. J. P. White, D. J. Williams, Tetrahedron 2001, 57,
947–956.
D. M. Guldi, A. Gouloumis, P. Vázquez, T. Torres, Chem.
Commun. 2002, 2056–2057.
M. R. Bryce, A. J. Moore, Synthesis 1991, 26.
[23]
[24]
[25]
N. Godbert, M. R. Bryce, S. Dahaoui, A. S. Batsanov, J. A. K.
Howard, P. Hazendonk, Eur. J. Org. Chem. 2001, 749–757.
a) P. R. Ashton, I. Baxter, S. J. Cantrill, M. C. T. Fyfe, P. T.
Glink, J. F. Stoddart, A. J. P. White, D. J. Williams, Angew.
Chem. Int. Ed. 1998, 37, 1294–1297; b) S. J. Cantrill, G. J.
Youn, J. F. Stoddart, D. J. Williams, J. Org. Chem. 2001, 66,
6857.
[26]
[12]
a) P. A. Liddell, G. Kodis, L. de la Garza, J. L. Bahr, A. L.
Moore, T. A. Moore, D. Gust, Helv. Chim. Acta 2001, 84, 2765;
b) D. Kreher, M. Cariou, S.-G. Liu, E. Levillain, J. Veciana, C.
Rovira, A. Gorgues, P. Hudhomme, J. Mater. Chem. 2002, 12,
2137 and references cited therein; c) G. Kodis, P. A. Liddell, L.
1
[27]
To perform the H NMR binding studies, the concentration of
16-H·PF6 was kept constant (1 m) and increasing amounts
of 21 were added (from 0.12 to 3.18 m).The variation of the
chemical shift of the ammonium protons was observed. A
5036
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 5027–5037

Supramolecular Threaded Complexes
homemade Montecarlo program was used for the calculation
of the association constant.
c) A. E. Jones, Ch. A. Christensen, D. F. Perepichka, A. S. Bat-
sanov, A. Beeby, P. J. Low, M. R. Bryce, A. W. Parker, Chem.
Eur. J. 2001, 7, 973.
[28] M. R. Bryce, A. J. Moore, J. Chem. Soc. Perkin Trans. 1 1991,
157.
[30] a) L. Echegoyen, L. E. Echegoyen, Acc. Chem. Res. 1998, 31,
593; b) B. M. Illescas, N. Martín, J. Org. Chem. 2000, 65, 5986.
Received: March 14, 2007
[29] a) Ch. A. Christensen, A. S. Batsanov, M. R. Bryce, J. Am.
Chem. Soc. 2006, 128, 10484–10490; b) D. M. Guldi, L.
Sánchez, N. Martín, J. Phys. Chem. B 2001, 105, 7139–7144;
Published Online: August 17, 2007
Eur. J. Org. Chem. 2007, 5027–5037
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5037