A new iterative approach for the synthesis of oligo(phenyleneethynediyl) derivatives and its application for the preparation of fullerene- oligo(phenyleneethynediyl) conjugates as active photovoltaic materials

Article abstract of DOI:10.1002/hlca.200490266

Disymmetrically substituted oligo(phenyleneethynediyl) (OPE) derivatives were prepared from 2,5-bis(octyloxy)-4-[(triisopropylsilyl)ethynyl]benzaldehyde (5) by an iterative approach using the following reaction sequence: i) Corey - Fuchs dibromoolefinatio

Full text of DOI:10.1002/hlca.200490266

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Helvetica Chimica Acta Vol. 87 (2004)
A New Iterative Approach for the Synthesis of
Oligo(phenyleneethynediyl) Derivatives and Its Application for the
Preparation of FullereneÀOligo(phenyleneethynediyl) Conjugates as Active
Photovoltaic Materials
by Jean-FranÁois Nierengarten*, and Tao Gu
¡
¡
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¬
¡
Groupe de Chimie des Fullerenes et des Systemes Conjugues, Ecole Europeenne de Chimie, Polymeres et
¬
¬
Materiaux (ECPM), Universite Louis Pasteur et CNRS (UMR 7504), 25 rue Becquerel,
F-67087 Strasbourg Cedex 2
(e-mail: jfnierengarten@chimie.u-strasbg.fr)
and Georges Hadziioannou*, Dimitris Tsamouras, and Victor Krasnikov
¬
¡
¬
¡
¬
Departement des Polymeres, Ecole Europeenne de Chimie, Polymeres et Materiaux (ECPM),
¬
Universite Louis Pasteur et CNRS, 25 rue Becquerel, F-67087 Strasbourg Cedex 2
(e-mail: hadzii@ecpm.u-strasbg.fr)
Disymmetrically substituted oligo(phenyleneethynediyl)(OPE)derivatives were prepared from 2,5-
bis(octyloxy)-4-[(triisopropylsilyl)ethynyl]benzaldehyde (5)by an iterative approach using the following
reaction sequence: i) Corey Fuchs dibromoolefination, ii)treatment with an excess of lithium diisopropyl-
amide, and iii)a metal-catalyzed cross-coupling reaction of the resulting terminal alkyne with 2,5-diiodo-1,4-
bis(octyloxy)benzene (3) (Schemes 2 and 3). Reaction of the OPE dimer 8 and trimer 13 thus obtained with N-
methylglycine and C60 in refluxing toluene gave the corresponding C60ÀOPE conjugates 16 and 17, respectively
(Scheme 4). On the other hand, treatment of the protected terminal alkynes 8 and 13 with Bu4N followed by
reaction of the resulting 9 and 14 with 4-iodo-N,N-dibutylaniline under Sonogashira conditions yielded 10 and
15, respectively (Schemes 2 and 3). Subsequent treatment with N-methylglycine and C60 in refluxing toluene
furnished the C60ÀOPE derivatives 18 and 19 (Scheme 4). Compound 9 was also subjected to a Pd-catalyzed
cross-coupling reaction with 3 to give the centrosymmetrical OPE pentamer 20 (Scheme 5). Subsequent
reduction followed by reaction of the resulting diol 21 with acid 22 under esterification conditions led to bis-
malonate 23. Oxidative coupling of terminal alkyne 14 with the Hay catalyst gave bis-aldehyde 24 (Scheme 6).
Treatment with diisobutylaluminium hydride followed by dicylcohexylcarbodiimide-mediated esterification
with acid 22 gave bis-malonate 26. Finally, treatment of bis-malonates 23 and 26 with C60, I2, and 1,8-
diazabicylco[5.4.0]undec-7-ene (DBU)in toluene afforded the bis[cyclopropafullerenes] 27 and 28, respectively
(Scheme 7). The C60 derivatives 16 19, 27, and 28 were tested as active materials in photovoltaic devices. Each
C60ÀOPE conjugate was sandwiched between poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)-cov-
ered indium tin oxide and aluminium electrodes. Interestingly, the performances of the devices prepared from
the N,N-dialkylaniline-terminated derivatives 18 and 19 are significantly improved when compared to those
obtained with 16, 17, 27, and 28, thus showing that the efficiency of the devices can be significantly improved by
increasing the donor ability of the OPE moiety.
1. Introduction. Following the preparation of the first photovoltaic devices from
C60Àoligo(phenyleneethenediyl)conjugates [1], a great deal of attention has been
devoted to C60 derivatives substituted with p-conjugated oligomers for solar-energy
conversion (for a review on fullerene-(p-conjugated oligomer)dyads as active
photovoltaic materials, see [2])[3 7]. This approach using molecular dyads as the
active layer in solar cells is particularly interesting since it restricts the dimension of the
¹ 2004 Verlag Helvetica Chimica Acta AG, Z¸rich

Helvetica Chimica Acta Vol. 87 (2004)2949
bicontinuous donor/acceptor network on the finest molecular level. The nanoscopic
dimension of the phase separation is an advantage because the exciton diffusion length
in conjugated systems is limited to that length scale [8]. In addition, another major
advantage of this approach is that the behavior of a unique molecule in a photovoltaic
cell allows to obtain easily structure activity relationships for a better understanding of
the photovoltaic system [2]. Actually, the molecular approach is not only an interesting
model system of the devices by means of bulk heterojunction materials but it appears
also as an excellent alternative to the polymeric approach. Indeed, the photosensitivity
and the energy-conversion efficiency obtained with devices prepared with fullerene-(p-
conjugated oligomer)dyads capable of achieving efficient and very fast photoinduced
charge separation are quite promising [4]. Furthermore, this new synthetic approach
also offers great versatility for design tuning of the photovoltaic system. As part of this
research, we have shown that C60 derivatives substituted with oligo(phenyleneethyne-
1,2-diyl)(OPE)subunits are interesting candidates for photovoltaic applications [6]. In
this paper, we now report a full account on the synthesis of a complete series of
C60ÀOPE conjugates. In particular, we show that the OPE precursors can be efficiently
prepared from a benzaldehyde derivative by an iterative approach using the following
reaction sequence: i) Corey Fuchs dibromoolefination [9] ii)treatment with an excess
of lithium diisopropylamide (LDA), and iii)a metal-catalyzed cross-coupling reaction
of the resulting terminal alkyne with a 4-iodobenzaldehyde derivative. This new
iterative methodology for the synthesis of OPE derivatives is an interesting alternative
to the approaches reported by Tour and co-workers [10] and Ziener and Godt [11]. On
the one hand, compared to the strategy based on the trimethylsilyl and the 3,3-
diethyltriazene functions as complementary protecting groups for terminal alkyne and
aryl iodide, respectively, it avoids the use of large amounts of rather volatile
carcinogenic methyl iodide [10]. On the other hand, compared to the strategy based
on the bromineÀiodine selectivity of the Pd-catalyzed alkyneÀarene coupling, which is
not always completely iodo-selective, it prevents the formation of undesirable
symmetric by-products [11]. The disymmetrically substituted OPE derivatives pre-
pared by using this new synthetic methodology have been attached to C60 by a 1,3-
dipolar cycloaddition of the azomethine ylides (ˆ iminium ylides)[12] generated in situ
from the corresponding OPE aldehydes and sarcosine. Symmetrically substituted OPE
derivatives bearing terminal malonate groups have also been synthesized and used for
the synthesis of dumbbell-shaped bis[cyclopropafullerene]ÀOPE systems. Finally, we
describe the preparation of photovoltaic devices from these C60ÀOPE derivatives. Part
of this work has been previously reported in preliminary communications [6].
2. Results and Discussions. 2.1. Synthesis. The preparation of the key building
block for the synthesis of the functionalized OPE derivatives is depicted in Scheme 1.
Reaction of hydroquinone (1)with 1-bromooctane in DMF at 80 8 in the presence of
K2CO3 gave 2 in 90% yield. Treatment of 2 with KIO3 and I2 in a mixture of AcOH,
conc. H2SO4 solution, and H2O at 808 [13] afforded 3 in 59% yield. Compound 4 was
then obtained in 85% yield by treatment of 3 with BuLi (1 equiv.)in Et O at 08
2
followed by quenching with DMF. It is worth noting that the purification of compounds
2 4 was simply achieved by recrystallization, and this route allowed us to easily
prepare building block 4 on a multi-gram scale.

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Scheme 1
a)1-Bromooctane, K 2CO3, DMF, 808, 24 h (90%). b) I2, KIO3, H2SO4, AcOH, 808, 12 h (59%). c)BuLi
(1 equiv.), Et2O, 08, 30 min, then DMF, 08 to r.t., 2 h (85%).
Compound 4 was subjected to a Pd-catalyzed cross-coupling reaction [14] with
(triisopropylsilyl)acetylene (ˆethynyltriisopropylsilane)to give 5 in 79% yield
(Scheme 2). Subsequent treatment with CBr4/PPh3/Zn under the conditions described
by CoreyÀFuchs [9] yielded dibromoolefine derivative 6 in a quantitative yield.
Elimination of HBr and halogen-metal exchange was best achieved with an excess of
LDA [15] in THF at À 788, and the resulting anion was quenched with NH4Cl to give
mono-protected bis-alkyne derivative 7 in 91% yield. The OPE dimer 8 was then
obtained in 79% yield by Pd-catalyzed cross-coupling between 4 and 7. Treatment of
the terminally protected alkyne derivative 8 with tetrabutylammonium fluoride
(Bu4NF)in THF at 0 8 afforded 9 in 91% yield. Subsequent Pd-catalyzed cross-
coupling reaction with N,N-dibutyl-4-iodoaniline under Sonogashira conditions then
gave 10.
The OPE tetramer was prepared similarly from dimer 8 by dibromoolefination
according to CoreyÀFuchs (!11), treatment with an excess of LDA in THF at À 788
and quenching with NH4Cl (!12). Pd-catalyzed cross-coupling reaction with 4 (!13),
treatment with Bu4NF (!14), and subsequent reaction with N,N-dibutyl-4-iodo-
aniline (Scheme 3). The yield of 15 was moderate since the by-product resulting from
the homocoupling of 14 was systematically formed in abnormally high proportions
under the conditions used in the last step. However, sufficient quantities of 15 were
obtained, and no further effort was made to optimize the reaction conditions for the
preparation of this OPE derivative.
The synthetic approach to prepare the C60ÀOPE conjugates 16 19 relies upon the
1,3-dipolar cycloaddition of the OPE azomethine ylides (ˆ iminium ylides)generated
in situ from the corresponding aldehydes and N-methylglycine (Scheme 4). This
methodology has been proven a powerful procedure for the functionalization of C60 due
to its versatility and the ready availability of the starting materials [12]. Thus, reaction
of aldehydes 8, 10, 13, and 15 with N-methylglycine and C60 in refluxing toluene gave
the corresponding fulleropyrrolidines 16 19 in 36 45% isolated yield after column
chromatography (silica gel). The structures of the C60ÀOPE conjugates 16 19 were
confirmed by analytical and spectroscopic data. The 1H-NMR spectra (CDCl3)of 16
19 exhibit the expected features with the signals arising from the OPE moieties, the
pyrrolidine protons (1 AB and 1s), as well as the MeN group (1s) . The13C-NMR
spectra of 16 19 were also in full agreement with their C1 symmetry resulting from the
presence of the asymmetric C-atom in the pyrrolidine ring. The structure of 16 19 was
further confirmed by the FAB-MS showing the expected molecular-ion peak in all the

Helvetica Chimica Acta Vol. 87 (2004)2951
Scheme 2
a)(Triisopropylsilyl)acetylene, [PdCl 2(PPh3)2)], CuI, Et3N, r.t., 24 h (79%). b)CBr 4, PPh3, Zn, CH2Cl2, 08 to
r.t., 12 h (99%). c)LDA, THF, < 788, then aq. NH4Cl soln. (91%). d) 4, [PdCl2(PPh3)2)], CuI, Et3N, r.t., 24 h
(79%). e)Bu NF, THF, 08 (91%). f) N,N-Dibutyl-4-iodoaniline, [PdCl2(PPh3)2)], CuI, Et3N, 258 (66%).
4
cases. For all the C60ÀOPE derivatives 16 19, the UV/VIS spectrum corresponds to
the sum of the spectra of their two components indicating no significant ground-state
interactions between the two chromophores. Preliminary luminescence measurements
show a strong quenching of the OPE fluorescence by the fullerene moiety in 16 19
indicating the occurrence of intramolecular photo-induced processes.
Symmetrically substituted OPE derivatives were also prepared and used for the
synthesis of dumbbell-shaped bis[fullerene]ÀOPE systems (Schemes 5 7) . In the
design of these compounds, it was decided to use Bingel-type chemistry [16] to attach
the two fullerene spheres to the conjugated system. Actually, the 1,3-dipolar cyclo-
addition of an azomethine ylide to C60 was not used because an asymmetric C-atom is
generated during the cycloaddition reaction. Therefore, the use of this methodology for
the preparation of p-conjugated systems bearing two fullerene spheres would yield a
diastereoisomer mixture [17].
For the preparation of the first symmetrically substituted OPE derivative bearing
terminal malonate groups, compound 9 was subjected to a Pd-catalyzed cross-coupling

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Scheme 3
a)CBr 4, PPh3, Zn, CH2Cl2, 08 to r.t., 12 h (99%). b)LDA, THF, À 788, then aq. NH4Cl soln. (92%). c) 4,
[PdCl2(PPh3)2)], CuI, Et3N, r.t., 24 h (77%). d)Bu 4NF, THF, 08 (92%). e) N,N-Dibutyl-4-iodoaniline,
[PdCl2(PPh3)2)], CuI, Et3N, 258 (21%).
reaction with 3 to give the centrosymmetrical OPE pentamer 20 in 79% yield.
Subsequent diisobutylaluminium hydride (DIBAL-H)reduction afforded the corre-
sponding diol 21 in 96% yield. Reaction of acid 22 with diol 21 under esterification
conditions in the presence of N,N'-dicyclohexylcarbodiimide (DCC)and N,N-
dimethylpyridin-4-amine (DMAP)led to bis-malonate 23 in 99% yield.
The second bis-malonate was prepared from bis-aldehyde 24 (Scheme 6)that was
obtained as a by-product during the reaction of 14 with N,N-dibutyl-4-iodoaniline
under Sonogashira conditions (see above). Compound 24 was also prepared by
oxidative coupling of terminal-alkyne derivative 14 with the Hay catalyst [18] (CuCl,

Helvetica Chimica Acta Vol. 87 (2004)2953
Scheme 4
a) 8 or 13, C60, N-methylglycine, toluene, reflux, 16 h (16: 36% from 8; 17: 40% from 13). b) 10 or 15, C60
N-methylglycine, toluene, reflux, 16 h (18: 39% from 10; 19: 45% from 15).
,
N,N,N',N'-tetramethylethane-1,2-diamine (TMEDA)) in CH2Cl2 in the presence of dry
air. Treatment of 24 with DIBAL-H followed by DCC-mediated esterification of the
resulting 25 with acid 22 gave the desired bis-malonate 26.
The functionalization of 23 and 26 with C60 is based on the Bingel reaction [16]
(Scheme 7). Nucleophilic addition of a stabilized a-halocarbanion to the C60 core,
followed by intramolecular nucleophilic substitution, leads to clean cyclopropanation
of C60. It has been shown that the a-halomalonate can be generated in situ, and direct
treatment of C60 with malonates in the presence of I2 [19] or CBr4 [20] under basic
conditions affords the corresponding cyclopropafullerenes in good yields. Treatment of
C
60 with bis-malonate 23, I2, and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)in toluene
at room temperature afforded bis[cyclopropafullerene] 27 in 38% yield. Similarly,
reaction of 26 with C60 in the presence of I2 and DBU gave the dumbbell-shaped
compound 28 in 32% yield. For both bis[cyclopropafullerene] derivatives 27 and 28, the
1H- and 13C-NMR spectra were in full agreement with their centrosymmetric structures.
In addition, the structures of 27 and 28 were also confirmed by MALDI-TOF-MS
showing the expected molecular-ion peaks. As seen for compounds 16 19, the UV/VIS
spectra of 27 and 28 correspond to the sum of the spectra of their component units
indicating no significant ground-state interactions between the different chromophores.
Preliminary luminescence measurements also show a strong quenching of the
characteristic OPE fluorescence by the fullerene subunits in 27 and 28 indicating the
occurrence of intramolecular photo-induced processes.

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Helvetica Chimica Acta Vol. 87 (2004)2957
2.2. Photovoltaic Devices. Compounds 16 19, 27, and 28 were tested as active
materials in photovoltaic devices. Each C60ÀOPE conjugate was sandwiched between
poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS)-covered in-
dium tin oxide (ITO)and aluminium electrodes. The organic layers were prepared by
spin-coating from CHCl3 solutions, and observations of the surface morphology by
atomic force microscopy (AFM)in the tapping mode revealed the presence of
continuous and uniform films for all the compounds. In all the cases, the largest features
of inhomogeneity and irregularities are smaller than 10% of the film thickness (ca.
100 nm)indicating the absence of pinholes. As a typical example, the surface
morphology of a film prepared from compound 18 is shown in Fig. 1.
Fig. 1. AFM Image (1.5 mm  1.5 mm) showing the surface morphology of a prepared film from compound 18
with a thickness of ca. 100 nm
The currentÀvoltage (I/V)characteristics of all the devices were determined in the
dark and under illumination (400 nm, 1 mW/cm2); the results are summarized in the
Table. As typical examples, the I/V characteristics of the devices prepared from 27 and
28 are depicted in Fig. 2. The results obtained with compounds 16 19 have already
been described in a previous report [6].
All the devices show clear photovoltaic behavior under illumination. Interestingly,
the performances of the devices prepared from the N,N-dialkylaniline terminated
derivatives 18 and 19 are significantly improved when compared to those obtained with
16, 17, 27, and 28. This can be related to the differences seen in their first oxidation

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Table. Results of the Photovoltaic Measurements for the Devices Prepared from 16 19, 27, and 28
VOC/V
ISC/A cmÀ2
FFa)
Tb)/%
S400/A WÀ1
he,400a)/%
16
17
18
19
27
28
0.22
0.58
0.54
0.59
0.50
0.42
2.05 ¥ 10À7
2.04 ¥ 10À7
1.16 ¥ 10À6
1.06 ¥ 10À6
3.8 ¥ 10À7
2.2 ¥ 10À7
0.27
0.22
0.32
0.29
0.33
0.30
55
27
22
39
42
44
2.41 ¥ 10À4
1.81 ¥ 10À4
1.46 ¥ 10À3
1.01 ¥ 10À3
3.6 ¥ 10À4
2.1 ¥ 10À4
1.2 ¥ 10À3
2.6 ¥ 10À3
2.0 ¥ 10À2
1.8 ¥ 10À2
6.3 ¥ 10À3
2.7 ¥ 10À3
a)The calculation of the overall energy-conversion efficiency he was done with the equation he ˆ (VOC ¥ ISC ¥ FF)/
PINC where VOC, ISC, FF and PINC are the open-circuit potential, short-circuit current, filling factor, and incident-
light power, respectively. The filling factor is given by FF ˆ (Vmax ¥ Imax)/VOC ¥ ISC where Vmax and Imax are voltage
and current, respectively, at the point of maximum power output. Standard intensity of light was 1 mW cmÀ2
.
b) Tˆ transmission (corrected on glass, ITO, and PEDOT-PSS).
potentials [6]. Indeed, due to the increased donor ability of the OPE moiety in 18 and
19 when compared to 16, 17, 27, and 28, the energy level of their charge-separated states
resulting from a photoinduced electron transfer is significantly lower in energy.
Therefore, the thermodynamic driving force is more favorable, thus electron transfer
which is one of the key steps for the photocurrent production must be more efficient for
18 and 19. As a result, the power conversion efficiency of the devices is increased by one
order of magnitude. As seen in the Table, the performances of the photovoltaic cells
prepared from all the compounds are rather low. Actually, a recent study has clearly
shown that an important limiting factor is the low charge-carrier mobility in the films
obtained from these C60ÀOPE conjugates [21].
3. Conclusions. OPE Derivatives were prepared by an iterative approach from
benzaldehyde derivatives by applying the following reaction sequence: i) Corey Fuchs
dibromoolefination and treatment with an excess of LDA; ii)metal-catalyzed cross-
coupling reaction of the resulting terminal alkyne with a 4-iodobenzaldehyde
derivative. The OPE building blocks prepared by using this new synthetic methodology
were used for the construction of various C60ÀOPE derivatives. These hybrid
compounds were incorporated in photovoltaic devices. Importantly, analysis of the
characteristics of these devices clearly revealed that the behavior of a unique molecule
in a photovoltaic cell allows to obtain easily structure activity relationships for a better
understanding of the photovoltaic system. In particular, we showed that the efficiency
of the devices can be significantly improved by increasing the donor ability of the OPE
moiety. However, for a commercial use, the efficiency and stability of such solar cells
have to be improved dramatically. For these purposes, new hybrid compounds with a
stronger absorption in the VIS range and a better stability towards light are needed. In
addition, the performances of the molecular photovoltaic cells are mainly limited by
their low conductivity. Therefore, a critical point appears to be the orientation of the
molecules within the thin film to improve the charge carrier mobility. In this respect,
the use of liquid-crystalline C60-(p-conjugated oligomer)conjugates could be of
particular interest since such materials would spontaneously form ordered assemblies
that could then be oriented and lead to high-performance thin films [22].

Helvetica Chimica Acta Vol. 87 (2004)2959
À2
*
*
)
Fig. 2. I/V Characteristics in the dark ( ) and under illumination at 400 nm with an intensity of 1 mW cm
(
for a) ITO/PEDOT-PSS/27/Al and b) ITO/PEDOT-PSS/28/Al
Experimental Part
General. Reagents and solvents were purchased as reagent grade and used without further purification.
Compound 22 [23] was prepared according to the literature. All reactions were performed in standard glassware
under Ar. Evaporation and concentration were done under water-aspirator pressure and drying in vacuo at
10À2 Torr. Column chromatography (CC): silica gel 60 (230 400 mesh, 0.040 0.063 mm)from E. Merck. TLC:
glass sheets coated with silica gel 60 F254 from E. Merck; visualization by UV light. UV/VIS spectra: Hitachi
U-3000 spectrophotometer; lmax in nm (e). NMR spectra: Bruker AC-200 (200 MHz)or Bruker AM-400
(400 MHz); solvent peaks as reference; d in ppm, J in Hz. FAB-MS: ZA-HF instrument; 4-nitrobenzyl alcohol

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Helvetica Chimica Acta Vol. 87 (2004)
as matrix; in m/z. MALDI-TOF-MS: Bruker BiflexTM mass spectrometer equipped with ScoutTM high-resolution
optics, an X-Y multi-sample probe, and a gridless reflector [24]; anthracene-1,8,9-triol(ˆdithranol)as matrix; in
m/z. Elemental analyses were performed by the analytical service at the Institut Charles Sadron, Strasbourg,
France.
1,4-Bis(octyloxy)benzene (2). A mixture of 1 (25.0 g, 0.227 mol), K2CO3 (157.0 g, 1.136 mol), and 1-
bromooctane (105.0 g, 0.545 mol)in DMF (300 ml)was stirred at 80 8 for 24 h and evaporated. The residue was
taken up with Et2O, the soln. washed (H2O), dried (MgSO4), and evaporated, and the residue recrystallized
from hexane: 2 (68.7 g, 90%). Colorless crystals. M.p. 568. 1H-NMR (200 MHz, CDCl3): 6.83 (s, 4 H); 3.90 (t, J ˆ
6, 4 H); 1.75 (m, 4 H); 1.57 1.30 (m, 20 H); 0.89 (t, J ˆ 6, 6 H). 13C-NMR (50 MHz, CDCl3): 153.16; 115.34;
68.62; 31.80; 31.50; 29.38; 29.24; 26.05; 22.64; 14.09. Anal. calc. for C22H38O2: C 78.99, H 11.45; found: C 78.91, H
11.43.
2,5-Diiodo-1,4-bis(octyloxy)benzene (3). A soln. of 2 (40.0 g, 0.120 mol), KIO3 (10.2 g, 0.048 mol), and I2
(33.4 g, 0.131 mol)in AcOH (200 ml)/conc. H 2SO4 soln. (3.6 ml)/H2O (15 ml)was stirred at 80 8 for 24 h. After
cooling, aq. Na2S2O3 soln. was added until the purple color dissappeared, then the mixture was poured into H2O
(500 ml)and extracted with CH 2Cl2. The org. layer was washed (H2O), dried (MgSO4), and evaporated.
Recrystallization from hexane afforded 3 (41.68 g, 59%). Colorless crystals. M.p. 498. 1H-NMR (200 MHz,
CDCl3): 7.18 (s, 2 H); 3.93 (t, J ˆ 6, 4 H); 1.74 (m, 4 H); 1.56 1.31 (m, 20 H); 0.90 (t, J ˆ 6, 6 H). 13C-NMR
(50 MHz, CDCl3): 152.79; 122.70; 86.27; 70.29; 31.77; 29.21; 29.11; 26.00; 22.64; 14.10. Anal. calc. for C22H36I2O2:
C 45.07, H 6.19; found: C 45.12, H 6.31.
4-Iodo-2,5-bis(octyloxy)benzaldehyde (4) . At 08, 1.6m BuLi in hexane (7.5 ml, 11.94 mmol)was added
dropwise to a stirred soln. of 3 (7.0 g, 11.94 mmol)in Et 2O (60 ml). The resulting mixture was stirred at 08 for
30 min, then a soln. of DMF (1.31 g, 17.92 mmol)in Et 2O (5 ml)was added dropwise. The mixture was stirred at
08 for 2 h, then sat. aq. NH4Cl soln. was added (100 ml). The org. layer was washed (H2O), dried (MgSO4), and
evaporated. Recrystallization from hexane afforded 4 (4.96 g, 85%). Colorless crystals. M.p. 71.58. 1H-NMR
(200 MHz, CDCl3): 10.19 (s, 1 H); 7.45 (s, 1 H) ; 7.18 (s, 1 H); 4.02 (t, J ˆ 7, 2 H); 4.00 (t, J ˆ 7, 2 H); 1.82 (m, 4 H) ;
1.59 1.29 (m, 20 H); 0.89 (t, J ˆ 6, 6 H). 13C-NMR (50 MHz, CDCl3): 189.12; 155.72; 152.11; 125.11; 124.48;
108.78; 96.72; 69.86; 69.42; 31.78; 29.22; 29.09; 29.01; 26.02; 25.99; 22.64; 14.10. Anal. calc. for C23H37I2O3: C
44.89, H 6.06; found: C 44.88, H 5.89.
2,5-Bis(octyloxy)-4-[(triisopropylsilyl)ethynyl]benzaldehyde (5)
. [PdCl(PPh3)2] (3 mol-%) and CuI
2
(5 mol-%)were added to a stirred degassed soln. of 4 (3.40 g, 6.96 mmol)and (triisopropylsilyla)cetylene
(1.27 g, 6.96 mmol)in dry Et 3N (70 ml)at r.t. The resulting mixture was stirred at r.t. for 48 h and then
evaporated. The residue was taken up in CH2Cl2 and the org. layer washed (H2O), dried (MgSO4), and
1
evaporated. CC (SiO2, hexane/CH2Cl2 3 :2)yielded 5 (3.02 g, 79%). Pale yellow crystals. M.p. 568. H-NMR
(200 MHz, CD2Cl2): 7.30 (s, 1 H) ; 7.24 (s , 1 H); 7.06 (s, 1 H); 4.03 (t, J ˆ 6, 2 H); 3.98 (t, J ˆ , 2 H) ; 1.80 (m, 4 H) ;
1.57 1.28 (m, 20 H); 1.14 (s, 21 H); 0.88 (t, J ˆ 6, 6 H). 13C-NMR (50 MHz, CD2Cl2): 189.19; 155.74; 154.70;
125.40; 120.49; 118.38; 109.65; 102.79; 99.79; 69.75; 69.56; 32.28; 32.20; 29.84; 29.76; 29.70; 29.62; 29.55; 26.59;
26.41; 23.09; 23.06; 18.83; 14.27; 11.71. Anal. calc. for C34H58O3Si: C 75.22, H 10.77; found: C 74.32, H 10.50.
{[4-(2,2-Dibromoethenyl)-2,5-bis(octyloxy)phenyl]ethynyl}triisopropylsilane (6) . A mixture of CBr
4
(28.76 g, 86.72 mmol), PPh3 (22.81 g, 86.72 mmol), and Zn dust (5.67 g, 86.72 mmol) in CH 2Cl2 (300 ml)was
stirred at r.t. for 24 h. The resulting suspension was then cooled to 08, and a soln. of 5 (9.41 g, 17.34 mmol)in
CH2Cl2 (40 ml)was added at once. The resulting mixture was slowly warmed to r.t. (over 1 h)and then stirred at
r.t. for 12 h. The resulting thick suspension was filtered over SiO2 (CH2Cl2)to remove the Zn salts and some of
the P-contaning by-products. The resulting soln. was evaporated and the residue subjected to CC (SiO2, hexane/
CH2Cl2 1:1): 6 (13.0 g, 100%). Yellow liquid. 1H-NMR (200 MHz, CDCl3): 7.61 (s , 1 H); 7.28 (s, 1 H); 6.89 (s,
1 H); 3.97 (t, J ˆ 6, 2 H); 3.93 (t, J ˆ 6, 2 H); 1.75 (m, 4 H); 1.56 1.30 (m, 20 H); 1.14 (s, 21 H); 0.89 (t, J ˆ 6,
6 H) . 13C-NMR (50 MHz, CDCl3): 154.00; 149.69; 132.39; 125.38; 116.84; 112.79; 102.99; 95.97; 92.28; 89.79;
69.51; 69.33; 31.86; 31.77; 29.49; 29.28; 29.23; 29.18; 26.20; 26.04; 22.67; 18.68; 14.12, 14.09; 11.34. Anal. calc. for
C35H58Br2O2Si: C 60.16, H 8.37; found: C 60.42, H 8.30.
{[4-Ethynyl-2,5-bis(octyloxy)phenyl]ethynyl}triisopropylsilane (7) . At À 788, 2m LDA in THF (27 ml,
54 mmol)was added dropwise to a soln. of 6 (12.11 g, 17.33 mmol)in THF (200 ml). The resulting mixture was
slowly warmed to r.t. (over 3 h), then a sat. aq. NH4Cl soln. (60 ml)was added, and the mixture diluted with
hexane. The org. layer was washed (H2O), dried (MgSO4), and evaporated. CC (SiO2, hexane/CH2Cl2 7:3)
yielded 7 (8.49 g, 91%). Pale yellow crystals. M.p. 408. 1H-NMR (200 MHz, CDCl3): 6.91 (s, 2 H); 3.98 (t, J ˆ 6,
2 H); 3.93 (t, J ˆ 6, 2 H); 3.32 (s , 1 H) ; 1.75 (m, 4 H); 1.56 1.25 (m, 20 H) ; 1.14 (s, 21 H); 0.89 (t, J ˆ 6, 6 H).
13C-NMR (50 MHz, CDCl3): 154.12; 153.87; 117.58; 117.12; 114.59; 112.55; 102.69; 96.61; 82.09; 80.04; 69.70;

Helvetica Chimica Acta Vol. 87 (2004)2961
69.24; 31.86; 31.78; 29.44; 29.41; 29.29; 29.21; 29.17; 26.15; 25.90; 22.67; 18.68; 14.09; 11.34. Anal. calc. for
C35H58O2Si: C 78.00, H 10.85; found: C 77.86, H 10.57.
4-{{2,5-Bis(octyloxy)-4-[(triisopropylsilyl)ethynyl]phenyl}ethynyl}-2,5-bis(octyloxy)benzaldehyde (8) . As
described for 5, with 4 (5.89 g, 12.06 mmol), 7 (6.50 g, 12.06 mmol), [PdCl2(PPh3)2] (3 mol-%), and CuI (5 mol-
%)in Et N (150 ml). CC (SiO2, hexane/CH2Cl2 7:3 ! 1:1)yielded 8 (7.50 g, 79%). Yellow crystals. M.p. 538.
3
UV/VIS (CH2Cl2): 400 (33410), 306 (23650). 1H-NMR (200 MHz, CDCl3): 8.15 (s , 1 H); 7.32 (s, 1 H) ; 7.10 (s,
1 H); 6.95 (s, 2 H); 4.07 3.92 (m, 8 H); 1.75 (m, 8 H); 1.56 1.29 (m, 40 H); 1.15 (s, 21 H); 0.88 (m, 12 H) .
13C-NMR (50 MHz, CDCl3): 189.10; 155.46; 154.27; 153.49; 153.37; 124.71; 120.75; 117.77; 116.44; 114.58;
113.62; 109.95; 102.82; 96.88; 94.01; 90.66; 69.73; 69.33; 69.18; 69.11; 31.85; 31.82; 31.77; 31.56; 29.45; 29.37;
29.29; 29.20; 29.15; 26.87; 26.20; 26.18; 26.05; 25.93; 22.64; 18.67; 14.05; 11.33. Anal. calc. for C58H94O5Si: C
77.45, H 10.53; found: C 77.38, H 10.50.
4-{[4-Ethynyl-2,5-bis(octyloxy)phenyl]ethynyl}-2,5-bis(octyloxy)benzaldehyde (9) . At 08, 1m Bu4NF in
THF (1.8 ml)was added to a stirred soln. of 8 (1.50 g, 1.67 mmol)in THF (100 ml)at 0 8. After 1 h, several drops
of H2O were added, and the mixture was diluted with CH2Cl2, washed with H2O, dried (MgSO4), and
evaporated. CC (SiO2, hexane/CH2Cl2 1 :1)gave 9 (1.13 g, 91%). Yellow solid. M.p. 458. UV/VIS (CH2Cl2): 395
(19600), 304 (14500). 1H-NMR (200 MHz, CDCl3): 8.15 (s, 1 H) ; 7.32 (s, 1 H); 7.10 (s, 1 H); 7.00 (s, 1 H); 6.99 (s,
1 H); 4.01 (m, 8 H); 3.36 (s, 1 H); 1.83 (m, 8 H); 1.57 1.27 (m, 40 H); 0.87 (m, 12 H) .13C-NMR (50 MHz,
CDCl3): 189.09; 155.46; 154.12; 153.56; 153.46; 124.84; 120.62; 117.92; 117.49; 117.04; 114.31; 113.21; 110.02;
93.56; 90.88; 82.55; 79.88; 69.67; 69.57; 69.37; 69.16; 31.81; 31.76; 31.56; 29.34; 29.29; 29.24; 29.19; 29.15; 26.05;
25.92; 22.62; 14.06; 14.03. Anal. calc. for C49H74O5: C 79.20, H 10.04; found: C 79.15, H 10.15.
4-{{4-{[4-(Dibutylamino)phenyl]ethynyl}-2,5-bis(octyloxy)phenyl}ethynyl}-2,5-bis(octyloxy)benzaldehyde
(10). As described for 5, with 9 (665 mg, 0.895 mmol), N,N-dibutyl-4-iodoaniline (349 mg, 1.074 mmol),
[PdCl2(PPh3)2] (3 mol-%), and CuI (5 mol-%) in Et 3N (30 ml). CC (SiO2, hexane/CH2Cl2 3 :2)gave 10
(560 mg, 66%). Yellow solid. M.p. 718. UV/VIS (CH2Cl2): 421 (45400), 314 (27600). 1H-NMR (200 MHz,
CDCl3): 8.15 (s, 1 H); 7.37 (d, J ˆ 8, 2 H); 7.32 (s, 1 H) ; 7.11 (s, 1 H); 6.99 (s, 2 H); 6.57 (d, J ˆ 8, 2 H); 4.04 (m,
8 H); 3.29 (t, J ˆ 7.5, 4 H); 1.85 (m, 8 H); 1.66 1.25 (m, 48 H); 0.97 (t, J ˆ 7, 6 H); 0.87 (m, 12 H) .13C-NMR
(50 MHz, CDCl3): 189.06; 155.48; 153.77; 153.42; 153.13; 147.96; 132.88; 124.58; 121.01; 117.37; 117.23; 116.59;
116.11; 112.22; 111.05; 109.95; 108.77; 97.18; 94.37; 90.42; 83.63; 69.59; 69.56; 69.35; 69.10; 50.63; 31.80; 31.74;
29.42; 29.29; 29.26; 29.17; 29.13; 26.10; 26.02; 25.94; 25.91; 22.66; 22.61; 20.26; 14.02; 13.93. Anal. calc. for
C63H95NO5: C 79.95, H 10.12, N 1.48; found: C 80.00, H 10.25, N 1.45.
{{4-{[4-(2,2-Dibromoethenyl)-2,5-bis(octyloxy)phenyl]ethynyl}-2,5-bis(octyloxy)phenyl}ethynyl}triisopro-
pylsilane (11). As described for 6, with CBr4 (7.58 g, 22.85 mmol), PPh3 (6.01 g, 22.85 mmol), Zn dust (1.50 g,
22.85 mmol), and 8 (4.11 g, 4.57 mmol)in CH 2Cl2 (200 ml). CC (SiO2, hexane/CH2Cl2 1 :1)gave 11 (5.14 g,
99%). Yellow solid. 1H-NMR (200 MHz, CDCl3): 7.64 (s, 1 H) ; 7.37 (s, 1 H); 6.97 (s, 1 H); 6.95 (s, 1 H); 6.94 (s,
1 H); 4.07 3.90 (m, 8 H); 1.90 1.77 (m, 8 H); 1.56 1.29 (m, 40 H); 1.15 (s, 21 H); 0.89 0.83 (m, 12 H) .
13C-NMR (50 MHz, CDCl3): 154.30; 153.18; 153.12; 149.94; 132.15; 125.19; 117.85; 116.33; 116.19; 114.32;
113.89; 113.44; 102.99; 96.35; 92.25; 91.26; 91.10; 89.65; 69.75; 69.14; 69.11; 31.83; 31.77; 31.56; 29.45; 29.39;
29.28; 29.21; 29.17; 26.87; 26.18; 26.04; 25.99; 25.94; 22.64; 18.67; 14.09; 14.05; 11.33. Anal. calc. for
C59H94Br2O4Si: C 67.15, H 8.98; found: C 67.34, H 8.95.
{{4-{[4-Ethynyl-2,5-bis(octyloxy)phenyl]ethynyl}-2,5-bis(octyloxy)phenyl}ethynyl}triisopropylsilane (12).
As described for 7, with 11 (4.82 g, 4.567 mmol), and 2m LDA in THF (11.42 ml)in dry THF (50 ml). CC
(SiO2, hexane/CH2Cl2 1:1)gave 12 (3.78 g, 92%). Yellow solid. M.p. 50 518. UV/VIS (CH2Cl2): 378 (37300),
1
309 (34000). H-NMR (200 MHz, CDCl3): 6.99 (s, 1 H); 6.97 (s, 1 H); 6.94 (s, 2 H); 4.05 3.92 (m, 8 H); 3.35 (s,
1 H); 1.87 1.71 (m, 8 H); 1.57 1.26 (m, 40 H); 1.15 (s, 21 H); 0.89 0.83 (m, 12 H) .13C-NMR (50 MHz,
CDCl3): 154.33; 154.14; 153.29; 153.25; 117.93; 117.87; 116.91; 116.43; 114.96; 114.23; 114.04; 112.52; 103.01;
96.46; 91.63; 91.01; 82.28; 80.04; 69.80; 69.70; 69.53; 69.16; 31.90; 31.85; 31.82; 29.50; 29.42; 29.34; 29.25; 29.18;
28.86; 25.99; 25.94; 22.67; 18.70; 14.09; 11.37. Anal. calc. for C59H94O4Si: C 79.14, H 10.58; found: C 79.16, H
10.92.
4-{{4-{{2,5-Bis(octyloxy)-4-[(triisopropylsilyl)ethynyl]phenyl}ethynyl}-2,5-bis(octyloxy)phenyl}ethynyl}-
2,5-bis(octyloxy)benzaldehyde (13). As described for 5, with 12 (2.0 g, 2.233 mmol)and 4 (1.09 g, 2.23 mmol)in
Et3N (30 ml). CC (SiO2, hexane/CH2Cl2 1:1)gave 13 (2.18 g, 77 %). Yellow crystals. M.p. 668. UV/VIS
(CH2Cl2) : 412 (51000), 318 (29200). 1H-NMR (200 MHz, CDCl3): 8.14 (s , 1 H); 7.32 (s, 1 H) ; 7.11 (s, 1 H); 7.01
(s, 2 H); 6.94 (s, 2 H); 4.09 3.92 (m, 12 H); 1.88 1.74 (m, 12 H); 1.56 1.27 (m, 60 H) ; 1.15 (s, 21 H); 0.89 0.83
(m, 18 H) .13C-NMR (50 MHz, CD2Cl2): 155.46; 154.30; 153.66; 153.50; 153.45; 153.23; 124.74; 120.79; 117.87;
117.43; 117.29; 117.13; 116.44; 114.99; 114.21; 114.07; 113.56; 109.98; 102.96; 96.51; 93.99; 91.92; 91.15; 90.86;

2962
Helvetica Chimica Acta Vol. 87 (2004)
69.78; 69.65; 69.57; 69.35; 69.13; 31.85; 31.82; 31.77; 31.56; 29.45; 29.37; 29.31; 29.20; 29.15; 26.87; 26.18; 26.05;
25.99; 25.94; 22.64; 18.67; 14.04; 11.34. Anal. calc. for C82H130O7Si: C 78.41, H 10.43; found: C 78.69, H 10.74.
4-{{4-{[4-Ethynyl-2,5-bis(octyloxy)phenyl]ethynyl}-2,5-bis(octyloxy)phenyl}ethynyl}-2,5-bis(octyloxy)benz-
aldehyde (14). As described for 9, with 13 (1.40 g, 1.11 mmol)and 1m Bu4N in THF (1.2 ml)in THF (100 ml). CC
(SiO2, hexane/CH2Cl2 1:1)gave 14 (1.13 g, 92%). Yellow solid. M.p. 738. UV/VIS (CH2Cl2): 408 (51300), 318
(28200), 273 (18300). 1H-NMR (200 MHz, CDCl3): 8.15 (s, 1 H) ; 7.32 (s, 1 H); 7.11 (s, 1 H); 7.02 (s, 2 H); 6.99 (s,
1 H); 6.98 (s, 1 H); 4.03 (m, 12 H); 3.35 (s, 1 H); 1.82 (m, 12 H); 1.56 1.26 (m, 60 H); 0.86 (m, 18 H) .13C-NMR
(50 MHz, CDCl3): 189.07; 155.45; 154.09; 153.63; 153.49; 153.45; 153.26; 124.74; 120.72; 117.90; 117.43; 117.26;
117.16; 116.94; 114.79; 113.68; 112.61; 109.97; 93.91; 91.49; 91.37; 90.90; 82.31; 79.96; 69.62; 69.59; 69.53; 69.33;
69.13; 31.80; 31.75; 29.37; 29.33; 29.26; 29.18; 29.12; 25.96; 25.90; 22.61; 14.02. Anal. calc. for C73H110O7: C 79.73,
H 10.08; found: C 79.97, H 10.26.
4-{{4-{{4-{[4-(Dibutylamino)phenyl]ethynyl}-2,5-bis(octyloxy)phenyl}ethynyl}-2,5-bis(octyloxy)phenyl}-
ethynyl}-2,5-bis(octyloxy)benzaldehyde (15). As described for 5, with 14 (700 mg, 0.64 mmol), N,N-dibutyl-4-
iodoaniline (253 mg, 0.76 mmol), [PdCl2(PPh3)2] (3 mol-%), and CuI (5 mol-%) in Et 3N (30 ml). CC (SiO2,
hexane/CH2Cl2 3 :2)gave 15 (180 mg, 21%). Yellow solid. M.p. 648. UV/VIS (CH2Cl2): 424 (90800), 322
1
(40800). H-NMR (200 MHz, CDCl3): 8.14 (s, 1 H) ; 7.37 (d, J ˆ 8, 2 H); 7.32 (s, 1 H) ; 7.11 (s, 1 H); 7.02 6.99 (m,
4 H); 6.57 (d, J ˆ 8, 2 H); 4.03 (m, 12 H); 3.29 (t, J ˆ 7, 4 H); 1.84 (m, 12 H); 1.57 1.28 (m, 68 H); 0.96 (t, J ˆ 7,
6 H); 0.87 (m, 18 H) .13C-NMR (50 MHz, CDCl3): 189.01; 155.43; 153.63; 153.58; 153.45; 153.34; 153.13; 147.90;
132.83; 124.68; 120.80; 117.39; 117.29; 117.16; 117.10; 116.60; 115.52; 113.32; 112.74; 111.03; 109.93; 108.85;
96.85; 94.05; 92.19; 90.85; 90.77; 83.67; 69.64; 69.56; 69.32; 69.08; 50.62; 31.80; 31.72; 29.42; 29.36; 29.28; 29.15;
29.10; 26.09; 26.01; 25.96; 25.88; 22.64; 22.61; 20.25; 14.02; 13.91. Anal. calc. for C87H130NO7: C 80.26, H 10.06, N
1.08; found: C 79.68, H 10.19, N 1.06.
5'-{4-{{2,5-Bis(octyloxy)-4-[(triisopropylsilyl)ethynyl]phenyl}ethynyl}-2,5-bis(octyloxy)phenyl}-1',5'-dihy-
dro-1'-methyl-2'H-[5,6]fullereno-C60-Ih-[1,9-c]imidazole (16) . A mixture of 8 (350 mg, 0.389 mmol), C60
(308 mg, 0.428 mmol), and N-methylglycine (208 mg, 2.334 mmol)in toluene (300 ml)was refluxed for 16 h.
After cooling, the mixture was filtered and evaporated. CC (SiO2, toluene/hexane 4 :1)gave 16 (230 mg, 36%).
Brown solid. M.p. 1248. UV/VIS (CH2Cl2): 303 (64100), 329 (47000), 363 (49900), 430 (48700), 702 (220).
1H-NMR (200 MHz, CDCl3): 7.58 (s , 1 H); 7.03 (s, 1 H); 6.93 (s, 1 H); 6.92 (s, 1 H); 5.54 (s, 1 H); 4.98 (d, J ˆ 9,
1 H); 4.32 (d, J ˆ 9, 1 H); 4.18 3.67 (m, 8 H); 2.83 (s, 3 H); 1.86 1.73 (m, 8 H); 1.58 1.28 (m, 40 H); 1.14 (s,
21 H); 0.88 0.84 (m, 12 H) .13C-NMR (50 MHz, CDCl3): 156.57; 154.97; 154.27; 154.03; 154.00; 153.71; 153.12;
151.43; 147.25; 146.69; 146.57; 146.22; 146.18; 146.14; 146.06; 146.02; 145.90; 145.68; 145.52; 145.41; 145.25;
145.19; 145.07; 144.56; 144.50; 144.42; 144.29; 143.00; 142.95; 142.63; 142.59; 142.51; 142.23; 142.20; 142.09;
142.04; 141.91; 141.69; 141.58; 140.13; 140.08; 139.65; 139.39; 136.39; 136.20; 136.07; 134.53; 127.12; 117.77;
116.41; 116.14; 114.72; 114.32; 113.75; 113.33; 102.99; 96.35; 91.33; 90.42; 76.48; 75.59; 69.97; 69.73; 69.19; 69.13;
68.58; 40.13; 31.88; 31.85; 31.82; 29.50; 29.45; 29.37; 29.28; 26.18; 26.04; 26.01; 25.91; 22.74; 22.67; 18.68; 14.18;
‡
‡
14.12; 14.09; 11.34. FAB-MS: 1647.7 (M , C120H99NO4Si ; calc. 1647.2). Anal. calc. for C120H99NO4Si: C 87.50, H
6.06; found: C 87.69, H 6.19.
5'-{4-{{4-{{2,5-Bis(octyloxy)-4-[(triisopropylsilyl)ethynyl]phenyl}ethynyl}-2,5-bis(octyloxy)phenyl}ethyn-
yl}-2,5-bis(octyloxy)phenyl}-1',5'-dihydro-1'-methyl-2'H-[5,6]fullereno-C60-Ih-[1,9-c]imidazole (17). As descri-
bed for 16, with 13 (400 mg, 0.318 mmol), C60 (252 mg, 0.350 mmol), and N-methylglycine (170 mg, 1.91 mmol)
in toluene (250 ml). CC (SiO2, toluene/hexane 1 :1)gave 17 (260 mg, 40%). Brown solid. M.p. 1088. UV/VIS
(CH2Cl2): 392 (70900), 326 (54600), 311 (67300). 1H-NMR (200 MHz, CDCl3): 7.59 (s, 1 H); 7.04 (s, 1 H); 6.99
(s, 2 H); 6.93 (s, 2 H); 5.55 (s, 1 H); 4.98 (d, J ˆ 9, 1 H); 4.32 (d, J ˆ 9, 1 H); 4.15 3.72 (m, 12 H); 2.84 (s, 3 H) ;
1.86 1.71 (m, 12 H); 1.57 1.28 (m, 60 H); 1.15 (s, 21 H); 0.89 0.85 (m, 18 H) .13C-NMR (50 MHz, CDCl3):
156.50; 154.92; 154.28; 153.96; 153.61; 153.39; 153.15; 151.41; 147.18; 146.61; 146.53; 146.11; 146.06; 146.02;
145.84; 145.62; 145.46; 145.33; 145.20; 145.12; 145.01; 144.50; 144.44; 144.34; 144.24; 142.94; 142.90; 142.57;
142.52; 142.44; 142.19; 142.14; 142.03; 141.98; 141.85; 141.63; 141.53; 140.08; 140.05; 139.60; 139.35; 136.33;
136.17; 135.99; 134.49; 127.12; 117.87; 117.19; 117.08; 117.05; 116.38; 116.22; 116.16; 114.75; 114.35; 114.24;
114.11; 113.86; 113.38; 102.99; 96.37; 91.57; 91.53; 91.34; 90.42; 76.45; 75.59; 75.54; 69.94; 69.77; 69.57; 69.14;
69.11; 68.54; 40.08; 31.85; 31.82; 29.44; 29.39; 29.34; 29.26; 26.17; 25.98; 25.93; 22.70; 22.64; 18.67; 14.17; 14.10;
‡
‡
14.05; 11.33. FAB-MS: 2003.9 (M , C144H135O6NSi ; calc. 2003.7). Anal. calc. for C144H135NO6Si: C 86.32, H 6.79,
N 0.70; found: C 86.58, H 6.87, N 0.71.
N,N-Dibutyl-4-{{4-{{4-(1',5'-dihydro-1'-methyl-2'H-[5,6]fullereno-C60-Ih-[1,9-c]imidazol-5'-yl)-2,5-bis(octyl-
oxy)phenyl}ethynyl}-2,5-bis(octyloxy)phenyl}ethynyl}benzenamine (18). As described for 16, with 10 (330 mg,
0.35 mmol), C60 (276 mg, 0.38 mmol), and N-methylglycine (186 mg, 2.09 mmol)in toluene (300 ml). CC (SiO
,
2
hexane/CH2Cl2 3 :7)gave 18 (230 mg, 39%). Dark brown solid. M.p. 1348. UV/VIS (CH2Cl2): 393 (85200), 328

Helvetica Chimica Acta Vol. 87 (2004)2963
(58800), 298 (71900). 1H-NMR (200 MHz, CDCl3): 7.58 (s, 1 H) ; 7.36 (d, J ˆ 8, 2 H); 7.04 (s, 1 H); 6.96 (s, 2 H) ;
6.56 (d, J ˆ 8, 2 H); 5.54 (s, 1 H), 4.98 (d, J ˆ 9, 1 H); 4.32 (d, J ˆ 9, 1 H); 4.15 3.67 (m, 8 H); 3.28 (t, J ˆ 7, 4 H );
2.84 (s, 3 H); 1.80 (m, 8 H); 1.66 1.27 (m, 48 H); 0.96 (t, J ˆ 7, 6 H); 0.89 (m, 12 H) .13C-NMR (50 MHz,
CDCl3): 156.53; 154.95; 154.03; 153.92; 153.64; 153.47; 153.10; 151.39; 147.84; 147.18; 146.62; 146.54; 146.14;
146.11; 146.06; 146.03; 146.00; 145.94; 145.84; 145.62; 145.46; 145.36; 145.19; 145.11; 145.01; 144.52; 144.44;
144.36; 144.24; 142.94; 142.89; 142.55; 142.52; 142.44; 142.19; 142.14; 142.09; 142.06; 142.03; 141.98; 141.85;
141.64; 141.60; 141.53; 140.08; 140.03; 139.60; 139.33; 136.35; 136.15; 136.01; 134.48; 132.83; 126.90; 117.16;
116.57; 116.14; 115.22; 114.80; 113.59; 112.95; 111.03; 108.93; 96.69; 91.02; 90.66; 83.70; 76.47; 75.57; 69.97;
69.72; 69.53; 69.16; 68.54; 50.62; 40.07; 31.85; 31.80; 31.53; 29.47; 29.42; 29.33; 29.25; 26.85; 26.09; 25.99; 25.90;
‡
‡
22.70; 22.64; 20.26; 14.15; 14.09; 14.05; 13.94. FAB-MS: 1694.1 (M , C125H100N2O4 ; calc. 1694.2). Anal. calc. for
C
125H100N2O4: C 88.62, H 5.95, N 1.65; found: C 88.35, H 6.25, N 1.69.
N,N-Dibutyl-4-{{4-{{4-{{4-(1',5'-dihydro-1'-methyl-2'H-[5,6]fullereno-C60-Ih-[1,9-c]imidazol-5'-yl)-2,5-bis-
(octyloxy)phenyl}ethynyl}-2,5-bis(octyloxy)phenyl}ethynyl}-2,5-bis(octyloxy)phenyl}ethynyl}benzenamine (19).
As described for 16, with 15 (140 mg, 0.11 mmol), C60 (86 mg, 0.12 mmol), and N-methylglycine (58 mg,
0.651 mmol)in toluene (100 ml). CC (SiO 2, hexane/CH2Cl2 3 :7)gave 19 (101 mg, 45%). Dark brown solid.
M.p. 708. UV/VIS (CH2Cl2): 702 (370), 404 (96300), 309 (72500). 1H-NMR (200 MHz, CDCl3): 7.59 (s, 1 H) ;
7.37 (d, J ˆ 8, 2 H); 7.04 (s, 1 H); 6.99 (s, 2 H); 6.98 (s, 2 H); 6.57 (d, J ˆ 8, 2 H); 5.55 (s, 1 H); 4.98 (d, J ˆ 9, 1 H);
4.32 (d, J ˆ 9, 1 H); 4.15 3.67 (m, 12 H); 3.29 (t, J ˆ 7, 4 H); 2.84 (s, 3 H) ; 1.82 (m, 12 H); 1.56 1.26 (m, 48 H) ;
0.96 (t, J ˆ 7, 6 H); 0.86 (m, 18 H) .13C-NMR (50 MHz, CDCl3): 156.55; 154.95; 154.03; 153.98; 153.68; 153.55;
153.39; 153.36; 153.15; 151.43; 147.90; 147.21; 146.65; 146.56; 146.18; 146.14; 146.10; 146.06; 146.02; 145.98;
145.87; 145.65; 145.49; 145.38; 145.22; 145.17; 145.14; 145.09; 145.04; 144.53; 144.47; 144.39; 144.31; 144.26;
142.97; 142.92; 142.60; 142.55; 142.47; 142.22; 142.17; 142.12; 142.09; 142.06; 142.01; 141.88; 141.68; 141.64;
141.55; 140.11; 140.06; 139.63; 139.36; 136.36; 136.19; 136.03; 134.51; 132.87; 132.74; 127.11; 117.19; 117.10;
116.68; 116.17; 115.38; 114.82; 114.35; 114.05; 113.43; 112.95; 111.05; 108.91; 96.78; 91.79; 91.45; 91.04; 90.46;
83.71; 76.48; 75.59; 69.97; 69.73; 69.61; 69.54; 69.18; 68.57; 50.65; 40.10; 31.86; 31.82; 29.44; 29.31; 29.28; 29.21;
‡
‡
26.10; 25.98; 25.94; 22.70; 22.62; 20.28; 14.17; 14.10; 14.07; 13.96. FAB-MS: 2051.1 ([M ‡ H] , C149H136N2O6
;
calc. 2050.7). Anal. calc. for C149H135O6N2: C 87.31, H 6.64, N 1.37; found: C 86.99, H 6.62, N 1.33.
4,4'-{[2,5-Bis(octyloxy)-1,4-phenylene]bis{ethyne-2,1-diyl[2,5-bis(octyloxy)-4,1-phenylene]ethyne-2,1-
diyl}}bis[2,5-bis(octyloxy)benzaldehyde] (20). As described for 5, with 9 (330 mg, 0.443 mmol), 3 (130 mg,
0.222 mmol), [PdCl2(PPh3)2)] (3 mol-%), and CuI (5 mol-%) in Et 3N (20 ml). CC (SiO2, hexane/CH2Cl2 1 :1)
gave 20 (320 mg, 79%). Orange solid. M.p. 1268. UV/VIS (CH2Cl2): 432 (89100), 323 (34100). 1H-NMR
(200 MHz, CDCl3): 8.14 (s, 2 H) ; 7.33 (s, 2 H); 7.11 (s, 2 H); 7.02 (s, 6 H); 4.04 (m, 20 H) ; 1.85 (m, 20 H); 1.56
1.19 (m, 100 H); 0.87 (m, 30 H) .13C-NMR (50 MHz, CDCl3): 189.07; 155.45; 153.64; 153.49; 153.44; 124.74;
117.43; 117.18; 114.93; 114.26; 113.62; 109.98; 93.96; 91.84; 91.45; 90.90; 69.62; 69.35; 69.13; 31.80; 31.75; 29.37;
29.29; 29.18; 29.13; 26.04; 25.98; 25.90; 22.62; 14.04. Anal. calc. for C120H182O12: C 79.33, H 10.10; found: C 79.21,
H 10.05.
4,4'-{[2,5-Bis(octyloxy)-1,4-phenylene]bis{ethyne-2,1-diyl[2,5-bis(octyloxy)-4,1-phenylene]ethyne-2,1-
diyl}}bis[2,5-bis(octyloxy)benzenemethanol] (21) . At 08, 1m of DIBAL-H (0.5 ml)was added to a soln. of 20
(300 mg, 0.165 mmol)in THF (40 ml). After 2 h, a few drops of H 2O were added, the mixture was then diluted
with CH2Cl2 and filtered. The soln. was dried (MgSO4), filtered, and evaporated. CC (SiO2, CH2Cl2)gave 21
(290 mg, 96%). Yellow solid. M.p. 1248. UV/VIS (CH2Cl2): 412 (86600), 318 (33500). 1H-NMR (200 MHz,
CDCl3): 7.01 (s, 6 H); 6.98 (s, 2 H); 6.89 (s, 2 H); 4.68 (d, J ˆ 6, 4 H); 4.03 (m, 20 H); 2.36 (t, J ˆ 6, 2 H); 1.83 (m,
20 H); 1.57 1.26 (m, 100 H); 0.87 (m, 30 H) .13C-NMR (50 MHz, CDCl3): 153.90; 153.44; 153.41; 153.36;
150.21; 130.95; 117.18; 115.52; 114.48; 114.24; 113.99; 113.60; 112.44; 91.57; 91.53; 91.39; 89.86; 69.83; 69.59;
68.49; 61.83; 31.80; 31.74; 29.36; 29.28; 29.18; 26.09; 25.94; 22.61; 14.01. Anal. calc. for C120H186O12: C 79.16, H
10.30; found: C 79.06, H 10.43.
Propanedioic Acid [2,5-Bis(octyloxy)-1,4-phenylene]bis{ethyne-2,1-diyl[2,5-bis(octyloxy)-4,1-phenylene]-
ethyne-2,1-diyl[2,5-bis(octyloxy)-4,1-phenylene]methylene} Bis{[3,5-bis(dodecyloxy)phenyl]methyl} Ester (23).
DCC (22 mg, 0.105 mmol)was added to a stirred soln. of 21 (160 mg, 0.088 mmol), 22 (109 mg, 0.193 mmol),
and DMAP (4.3 mg, 0.035 mmol)in CH 2Cl2 (50 ml)at 0 8. After 1 h, the mixture was allowed to slowly warm to
r.t. (within 1 h), then stirred for 12 h, filtered, and evaporated. CC (SiO2, CH2Cl2/hexane 4 :1)gave 23 (251 mg,
98%). Yellow glassy product. 1H-NMR (200 MHz, CDCl3): 7.02 6.92 (m, 8 H); 6.47 6.40 (m, 8 H); 5.24 5.03
(m, 8 H); 4.03 3.88 (m, 28 H); 3.52 3.43 (m, 4 H); 1.79 (m, 28 H); 1.59 1.27 (m, 172 H); 0.87 (m, 42 H) .
13C-NMR (50 MHz, CDCl3): 166.16; 166.08; 160.36; 153.69; 153.41; 150.25; 137.11; 132.23; 132.02; 131.40;
131.33; 128.48; 128.24; 125.24; 117.15; 115.82; 114.39; 114.24; 114.08; 113.51; 106.14; 100.98; 91.52; 91.41; 90.13;

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Helvetica Chimica Acta Vol. 87 (2004)
69.75; 69.54; 68.68; 67.90; 67.05; 66.16; 65.58; 62.42; 41.41; 31.83; 31.78; 29.58; 29.55; 29.34; 29.26; 29.15; 25.96;
22.59; 14.01.
4,4'-{But-1,3-diyne-1,4-diylbis{[2,5-bis(octyloxy)-4,1-phenylene]ethyne-2,1-diyl[2,5-bis(octyloxy)-4,1-phen-
ylene]ethyne-2,1-diyl}}bis[2,5-bis(octyloxy)benzaldehyde] (24). CuCl (100 mg, 1.01 mmol) and TMEDA (1 ml,
6.60 mmol)were added to a soln. of 14 (176 mg, 0.160 mmol)in CH 2Cl2 (70 ml). The resulting mixture was
vigorously stirred for 12 h in the presence of dry air, then filtered over a short SiO2 plug (CH2Cl2)and
evaporated. CC (SiO2, hexane/CH2Cl2 1:1)gave 24 (160 mg, 91%). Yellow solid. M.p. 1138. UV/VIS (CH2Cl2):
440 (134000), 324 (50000). 1H-NMR (200 MHz, CDCl3): 8.15 (s, 2 H); 7.33 (s, 2 H); 7.11 (s, 2 H) ; 7.02 (s, 4 H) ;
7.00 (s, 4 H); 4.03(m, 24 H) ; 1.83 (m, 24 H); 1.56 1.27 (m, 120 H); 0.87 (m, 36 H) .13C-NMR (50 MHz, CDCl3):
189.06; 155.45; 154.94; 153.64; 153.49; 153.29; 124.78; 120.72; 117.80; 117.43; 117.27; 117.18; 116.99; 115.28;
114.75; 113.78; 112.58; 110.00; 93.93; 92.04; 91.63; 90.96; 79.56; 79.34; 69.64; 69.35; 69.13; 31.80; 31.74; 29.37;
29.33; 29.28; 29.21; 29.17; 29.12; 25.96; 25.91; 22.62; 14.02. Anal. calc. for C146H218O14: C 79.81, H 10.00; found: C
79.42, H 10.10.
4,4'-{But-1,3-diyne-1,4-diylbis{[2,5-bis(octyloxy)-4,1-phenylene]ethyne-2,1-diyl[2,5-bis(octyloxy)-4,1-phen-
ylene]ethyne-2,1-diyl}}bis[2,5-bis(octyloxy)benzenemethanol] (25). As described for 21, with 24 (200 mg,
0.091 mmol)and 1 m DIBAL-H in hexane (0.3 ml)in THF (20 ml). CC (SiO 2, CH2Cl2)gave 25 (190 mg, 95%).
Orange solid. M.p. 1128. UV/VIS (CH2Cl2): 427 (106000), 315 (42000). 1H-NMR (200 MHz, CDCl3): 7.02 6.98
(m, 10 H); 6.90 (s, 2 H); 4.68 (d, J ˆ 6, 4 H); 4.02 (m, 24 H); 2.37 (t, J ˆ 6, 2 H); 1.83 (m, 24 H); 1.59 1.18 (m,
120 H); 0.87 (m, 36 H) .13C-NMR (50 MHz, CDCl3): 154.94; 153.95; 153.53; 153.39; 150.29; 130.97; 117.83;
117.27; 116.99; 115.58; 115.44; 114.71; 113.83; 113.73; 112.52; 112.46; 92.22; 91.66; 91.18; 89.86; 79.56; 79.29;
69.89; 69.65; 68.54; 61.98; 31.82; 31.77; 29.37; 29.29; 29.21; 26.12; 25.96; 22.62; 14.04. Anal. calc. for C120H186O12
C 79.66, H 9.25; found: C 79.47, H 9.24.
:
Propanedioic Acid But-1,3-diyne-1,4-diylbis[2,5-bis(octyloxy)-4,1-phenylene]ethyne-2,1-diyl[2,5-bis(octyl-
oxy)-4,1-phenylene]ethyne-2,1-diyl[2,5-bis(octyloxy)-4,1-phenylene]methylene} Bis{[3,5-bis(dodecyloxy)phe-
nyl]methyl} Ester (26). As described for 23, with 25 (130 mg, 0.059 mmol), 22 (73 mg, 0.130 mmol), DCC
(30 mg, 0.145 mmol), and DMAP (2.89 mg, 0.024 mmol) in CH 2Cl2 (50 ml). CC (SiO2, CH2Cl2)gave 25
(194 mg, 100%). Orange glassy product. 1H-NMR (200 MHz, CDCl3): 7.01 6.91 (m, 10 H); 6.47 6.40 (m,
8 H); 5.24 5.02 (m, 8 H); 4.01 3.88 (m, 32 H); 3.51 3.49 (m, 4 H); 1.79 (m, 32 H); 1.57 1.26 (m, 156 H); 0.87
(m, 48 H) .13C-NMR (50 MHz, CDCl3): 166.24; 166.14; 160.41; 154.92; 153.72; 153.52; 153.42; 150.31; 137.14;
125.30; 117.82; 117.23; 116.96; 115.90; 115.41; 114.61; 114.27; 113.91; 113.52; 112.44; 106.23; 101.04; 100.85;
92.20; 91.52; 91.21; 90.13; 79.55; 79.29; 69.83; 69.62; 68.76; 67.98; 67.13; 66.22; 62.49; 41.46; 31.86; 31.80; 29.57;
29.36; 29.29; 29.20; 29.12; 25.99; 25.91; 22.62; 14.05.
3'H-Cyclopropa[1,9][5,6]fullerene-C60-Ih-3',3'-dicarboxylic Acid [2,5-Bis(octyloxy)-1,4-phenylene]bis-
{ethyne-2,1-diyl[2,5-bis(octyloxy)-4,1-phenylene]ethyne-2,1-diyl[2,5-bis(octyloxy)-4,1-phenylene]methylene}
Bis{[3,5-bis(dodecyloxy)phenyl]methyl} Ester (27) . A soln. of 23 (250 mg, 0.086 mmol), C60 (136 mg,
0.189 mmol), DBU (0.1 ml, 0.695 mmol), and I 2 (54.5 mg, 0.215 mmol)in toluene (300 ml)was stirred for
6 h at r.t., then filtered over a short SiO2 plug (CH2Cl2), and evaporated. CC (SiO2, hexane/CH2Cl2 1:1)gave 27
(145 mg, 38%). Brown solid. M.p. 958. UV/VIS (CH2Cl2): 324 (99800), 411 (95400), 688 (200). 1H-NMR
(400 MHz, CDCl3): 7.05 (s, 2 H); 7.03 (s, 2 H); 7.02 (s, 2 H); 7.00 (s, 2 H); 6.97 (s, 2 H); 6.59 (s, 2 H); 6.58 (s, 2 H) ;
6.40 (t, J ˆ 2, 2 H); 5.58 (s, 4 H); 5.43 (s, 4 H); 4.05 3.87 (m, 28 H) ; 1.84 (m, 20 H) ; 1.73 (m, 8 H); 1.55 1.26 (m,
172 H); 0.89 (m, 42 H) .13C-NMR (50 MHz, CDCl3): 163.42; 160.45; 153.67; 153.45; 153.41; 150.61; 145.13;
145.10; 145.05; 145.02; 144.96; 144.80; 144.59; 144.46; 144.40; 143.74; 142.91; 142.85; 142.10; 141.83; 141.75;
140.79; 140.76; 139.26; 138.70; 136.50; 124.53; 117.23; 115.95; 114.87; 114.34; 114.26; 114.22; 114.17; 106.84;
101.62; 91.54; 91.49; 91.33; 90.51; 71.42; 69.86; 69.62; 68.86; 68.06; 64.16; 51.90; 31.89; 31.83; 29.67; 29.61; 29.38;
‡
‡
29.34; 29.30; 29.26; 26.08; 26.05; 25.98; 25.95; 22.63; 14.09; 14.06. MALDI-TOF-MS: 4347.9 (M , C308H294O22
;
calc. 4347.7). Anal. calc. for C308H294O22: C 85.08, H 6.82; found: C 84.85, H 6.99.
3'H-Cyclopropa[1,9][5,6]fullerene-C60-Ih-3',3'-dicarboxylic Acid But-1,3-diyne-1,4-diylbis{[2,5-bis(octyl-
oxy)-4,1-phenylene]ethyne-2,1-diyl[2,5-bis(octyloxy)-4,1-phenylene]ethyne-2,1-diyl[2,5-bis(octyloxy)-4,1-phe-
nylene]methylene} Bis{[3,5-bis(dodecyloxy)phenyl]methyl} Ester (28). As described for 27, with 26 (194 mg,
0.059 mmol), C60 (94 mg, 0.130 mmol), I2 (38mg, 0.147 mmol), and DBU (0.1 ml, 0.695 mmol) in toluene
(200 ml). CC (SiO2, hexane/CH2Cl2 1:1)gave 28 (90 mg, 32%). Brown solid. UV/VIS (CH2Cl2): 426 (12600),
320 (11500), 257 (27900). 1H-NMR (200 MHz, CDCl3): 7.05 6.97 (m, 12 H); 6.58 6.39 (m, 6 H); 5.58 (s, 4 H) ;
5.43 (s, 4 H); 4.01 3.85 (m, 32 H); 1.81 (m, 32 H); 1.58 1.26 (m, 156 H); 0.88 (m, 48 H) .13C-NMR (50 MHz,
CDCl3): 163.46; 163.43; 160.46; 154.94; 153.68; 153.53; 153.42; 153.26; 150.63; 145.14; 145.09; 145.03; 144.96;
144.80; 144.60; 144.47; 144.40; 143.75; 142.92; 142.86; 142.11; 141.84; 141.76; 140.80; 140.77; 139.27; 138.71;
136.51; 130.86; 128.80; 124.58; 117.83; 117.31; 117.23; 117.00; 116.00; 115.41; 114.93; 114.55; 114.21; 113.99;

Helvetica Chimica Acta Vol. 87 (2004)2965
112.47; 106.87; 101.65; 92.20; 91.42; 91.28; 90.50; 79.58; 79.33; 71.46; 69.89; 69.67; 68.87; 68.07; 64.21; 53.39;
31.91; 31.83; 29.68; 29.63; 29.41; 29.36; 29.23; 26.10; 26.05; 26.01; 25.98; 25.93; 22.66; 14.12; 14.07. MALDI-TOF-
‡
‡
MS: 4728.5 (M , C334H330O24 ; calc. 4728.3). Anal. calc. for C334H330O24: C 84.84, H 7.03; found: C 84.52, H 7.31.
Photovoltaic Devices. The substrates utilized were always 20 Â 20 mm ITO-coated glass slices. In all cases
and prior to film deposition, substrates were cleaned ultrasonically by repeating at least twice a procedure
including successive washing steps with 35% H2O2 soln./ammonia/H2O solution 1 :1:5 (v/v), EtOH, and
acetone. Just before application of the active layer, every substrate was spin-coated by a layer of PEDOT-PSS
(Baytron P, Bayer AG)as a hole injection/transport layer resulting in a thickness of ca. 70 nm, as measured by a
Dektak-3130 surface profiler. Subsequently they were left to dry at 10À6 Torr for several hours at an elevated
temperature. Active-layer films were fabricated by spin-coasting (ca. 1000 rpm)from 2% ( w/w)CHCl solns.
3
(thickness ca. 100 nm as measured by a Dektak-3130 surface profiler). Finally, Al electrodes were vapor-
deposited at a dynamic vacuum around 3 ¥ 10À7 Torr on the top of the structure, with a deposition rate of 0.4 nm/
s, to a thickness of 100 nm. I/V curves were measured with a Keithley-236-source measure unit, while an Oriel-
60100 xenon lamp and a CVI-Digikrom-120 monochromator provided illumination through the ITO side. In
forward bias, the ITO electrode was wired as the anode. The impedance spectroscopy was carried out with a
Solartron-SI1260 impedance/gain phase analyzer. A standard calibrated silicon photodiode was used to record
the action photovoltaic spectra. All measurements were performed in a glovebox under N2.
Morphology Characterization. The compounds were spin-coated from 2% (w/w)CHCl solns. on cleaved
3
mica and examined by AFM by using a Digital Nanoscope III. Silicon cantilevers were used to acquire
topography images in the tapping mode at r.t. under ambient conditions.
This work was supported by the CNRS, the French Ministry of Research (ACI Jeunes Chercheursto J.-F. N.),
the European Community (Contract N8 HPRN-CT-2002-00171), and ECODEV (ADEME-CNRS). We further
thank L. Oswald for technical help, M. Schmitt for the NMR measurements, and R. Hueber for the mass spectra.
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Received July 9, 2004