Synthesis of perylene-3,4-mono(dicarboximide)-fullerene C60 dyads as new light-harvesting systems

Article abstract of DOI:10.1021/jo800804z

(Graph Presented) Fullerene C₆₀-perylene-3,4-mono(dicarboximide) (C₆₀-PMI) dyads 1-3 were synthesized in the search for new light-harvesting systems. The synthetic strategy to the PMI intermediate used a cross-coupling Suzuki reaction for the introduction of a formyl group in the ortho, meta, or para position. Subsequent 1,3-dipolar cycloaddition with C ₆₀ led to the target C₆₀-PMI dyad. Cyclic voltammetry showed that the first one-electron reduction process unambiguously occurs onto the C₆₀ moiety and the following two-electron process corresponds to the concomitant second reduction of C₆₀ and the first reduction of PMI. A quasi-quantitative quenching of fluorescence was shown in dyads 1-3, and an intramolecular energy transfer was suggested to occur from the PMI to the fullerene moiety. These C₆₀-PMI dyads constitute good candidates for future photovoltaic applications with expected well-defined roles for both partners, i.e., PMI acting as a light-harvesting antenna and C₆₀ playing the role of the acceptor in the photoactive layer.

Full text of DOI:10.1021/jo800804z

Synthesis of Perylene-3,4-mono(dicarboximide)-Fullerene C60 Dyads
as New Light-Harvesting Systems
Je´roˆme Baffreau, Lucie Ordronneau, Ste´phanie Leroy-Lhez, and Pie´trick Hudhomme*
UniVersite´ d’Angers, CNRS, Laboratoire de Chimie et Inge´nierie Mole´culaire d’Angers, CIMA UMR 6200,
2 BouleVard LaVoisier, 49045 Angers, France
pietrick.hudhomme@uniV-angers.fr
ReceiVed April 15, 2008
Fullerene C60-perylene-3,4-mono(dicarboximide) (C60-PMI) dyads 1-3 were synthesized in the search
for new light-harvesting systems. The synthetic strategy to the PMI intermediate used a cross-coupling
Suzuki reaction for the introduction of a formyl group in the ortho, meta, or para position. Subsequent
1,3-dipolar cycloaddition with C60 led to the target C60-PMI dyad. Cyclic voltammetry showed that the
first one-electron reduction process unambiguously occurs onto the C60 moiety and the following two-
electron process corresponds to the concomitant second reduction of C60 and the first reduction of PMI.
A quasi-quantitative quenching of fluorescence was shown in dyads 1-3, and an intramolecular energy
transfer was suggested to occur from the PMI to the fullerene moiety. These C60-PMI dyads constitute
good candidates for future photovoltaic applications with expected well-defined roles for both partners,
i.e., PMI acting as a light-harvesting antenna and C60 playing the role of the acceptor in the photoactive
layer.
Introduction
devoted to photovoltaic applications, PDI was recently attached
to fullerene C60 with the aim of reaching new light-harvesting
systems 4 and 5 (Scheme 1).7,8
In recent years, there has been an increasing interest in the
design of new advanced materials using the perylene-3,4:9,10-
bis(dicarboximide) (PDI) chromophore.1 More recent applica-
tions are in the field of electronic materials, these dyes being
considered as one of the more efficient n-type semiconductors
now available.2 Thanks to their unique light-harvesting, redox,
and thermal stability properties, PDI dyes have been regarded
as potential candidates for applications in xerography,3 organic
field-effect transistors,4 organic light-emitting diodes,5 and
organic solar cells.6 In the search for new organic materials
(4) (a) Dimitrakopoulos, C. D.; Malenfant, P. R. L. AdV. Mater. 2002, 14,
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1-3.
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10.1021/jo800804z CCC: $40.75 2008 American Chemical Society
Published on Web 07/22/2008

Perylene-3,4-mono(dicarboximide)-Fullerene C60 Dyads
SCHEME 1. C60-PMI dyads 1-3 and C60-PDI Dyads 4
and 5
SCHEME 2. Synthesis of Dyads C60-PMI 1-3
An efficient intramolecular energy transfer from the PDI
toward fullerene C60 was evidenced in dyads 4 and 5.9,10 Bulk-
heterojunction solar cells were designed by mixing the donor
polymer poly(3-hexylthiophene) with the C60-PDI dyad con-
sidering that in the photoactive layer the dye should act as a
light-harvesting antenna while an electron transfer should occur
selectively from the p-type polymer to the C60 unit.11 Whereas
it was reported in such dyads that C60 and PDI are reduced at
the same potential when PDI is substituted by hydrogen atoms
(∆E ) E1red(C60) - E1red(PDI) ) 0 mV),8d the electron-accepting
character of PDI was shown to be affected by the introduction
of electron-donating or -withdrawing groups at the PDI bay
region (for R ) Cl, ∆E ) -240 mV in dyad 4 and for R )
OPh-t-Bu, ∆E ) +140 mV in dyad 5) with a consequence on
photovoltaic characteristics.11
Our following objective was to design new light-harvesting
C60 based systems in which (i) C60 should be unambiguously
the better electron acceptor (∆E > 0 mV) with a higher
discrimination between the first reduction potential of C60 and
that of the dye and (ii) an efficient energy transfer should also
occur from the antenna toward C60. With this aim, we were
interested in replacing the dye PDI by the less accepting dye
perylene-3,4-mono(dicarboximide) (PMI). We report herein an
efficient synthetic route to C60-PMI dyads 1-3 and their
electrochemical and spectroscopic properties (Scheme 2).
Whereas chemistry of PDI has been largely developed in
recent years,1,12 the synthesis of PMI derivatives has been less
investigated. A series of donor-PMI systems have been reported
in the literature in which PMI was attached to oligothiophene,13
polyphenylene oligomers14 or dendrimers,15 based-tripheny-
lamine derivatives,16 or zinc porphyrin17 in the search of
donor-acceptor electronic interactions. To our knowledge, PMI
has never been attached to an acceptor such as fullerene C60.18
Results and Discussion
Synthesis. The strategy for the synthesis of PMI-C60 dyads
1-3 used the starting material N-(2,6-diisopropylphenyl)-
perylene-3,4-mono(dicarboximide) 6. The 9-bromo-PMI deriva-
tive 7 was synthesized by treating PMI 6 with bromine in
chlorobenzene according to reported procedure.19 Under our
conditions, compound 7 was isolated in 83% yield and was
accompanied by a small amount of the 1,6,9-tribominated
derivative.20 In our different attempts to optimize the yield in
compound 7, we could also isolate a mixture of 1,9- and 1,10-
dibromo-PMI derivative (yield <5%). Subsequent palladium-
catalyzed Suzuki-type cross-coupling of 9-brominated PMI 7
with commercially available formyl-substituted boronic acid in
refluxing 1,2-dimethoxyethane (DME) overnight afforded in
high yields 9-phenyl-PMI derivatives (8o: 94%; 8m: 86%; 8p:
88%). Using ultrasound conditions,21 the Suzuki reaction time
could be reduced to 3 h but yields remained lower (8o: 55%;
8m: 63%; 8p: 73%). The subsequent 1,3-dipolar cycloaddition22
(8) (a) For other dyads and triads incorporating both C60 and PDI units which
have been recently described, see: (a) Hua, J.; Meng, F.; Ding, F.; Tian, H. Chem.
Lett. 2004, 33, 432–433. (b) Hua, J.; Meng, F.; Ding, F.; Li, F.; Tian, H. J.
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J. Org. Chem. Vol. 73, No. 16, 2008 6143

Baffreau et al.
FIGURE 1. Optimized geometries of C60-PMI dyads 1 (left), 2 (right),
and 3 (bottom).
FIGURE 2. Deconvoluted cyclic voltammogram of dyad 1. Experi-
mental conditions are detailed in Table 1.
was carried out using C60 and N-methylglycine (sarcosine) in
refluxing toluene affording, after purification by silica gel
column chromatography, dyads 1-3 in satisfactory 25-50%
yields. Subsequent purification of dyads 1-3 and references
(PMI 6 and C60 derivative 9) was carried out by analytical and
semipreparative HPLC. The purity of dyads 1-3 could be
estimated to be higher to 99.8%. Information on the steric
TABLE 1. Redox Potential Values (V vs Fc+/Fc) of PMI-C60
Dyads 1-3 and Reference Compounds 6 and 9a
E4
E3
E2
E1
E1
E2
red
red
red
red
ox
ox
1
2
3
6
9
-2.14
-2.12
-2.11
-2.03
-1.99
-1.97
-1.56b
-1.55b
-1.55b
-1.99
-1.58
-1.20
-1.19
-1.20
-1.54
-1.21
+0.81c
+0.88d
+0.85c
+0.92d
+0.89c
+0.98d
+0.96d
1
interaction between PMI and C60 in solution is given by H
-2.09
NMR spectra of dyads 1-3. Whereas the four methyl groups
(from both diisopropylphenyl groups) appear as a single doublet
in the para derivative 3, two and four doublets were observed
in the case of the meta 2 and ortho 1 derivatives, respectively.
Fulleropyrrolidine 9 was prepared in 40% yield by using
benzaldehyde as the starting material to generate the azomethine
ylide.23
a Values recorded in
a o-dichlorobenzene/CH2Cl2 (2:1) solution
(5.10-4 M) using Bu4NPF6 0.1M as the supporting electrolyte, platinum
wires as counter and working electrodes. Scan rate: 100 mV/s. b Two
one-electron process; c Irreversible process; d Quasi-irreversible process.
orbitals which predicted that the LUMO of the system would
be located on C60 whereas the HOMO would be on the PMI
moiety. The following two-electron process corresponds to the
generation of the C602--PMI•- species, suggesting that the
second reduction process of C60 and the first reduction process
of PMI are overlapping. Consequently, such an important
difference (∆E ) E1red(C60) - E1red(PMI) ) + 350 mV) will
make C60 the unambiguous electron acceptor when this dyad
will be incorporated in a bulk-heterojunction device with the
donor polymer.
The third and fourth one-electron waves result from the
formation of C602--PMI2- and C603•--PMI2- species, respec-
tively. Due to the close proximity of oxidation potentials of
C60 and PMI references (9 and 6), corresponding oxidation
processes occurring in the dyads could not be formally ascribed.
Moreover, comparison of these different values for dyads 1, 2,
and 3 with reference compounds 6 and 9 suggests that no
significant interaction takes place between both electroactive
moieties in the ground state.
Absorption and Steady-State Fluorescence Emission. Ab-
sorption and steady-state fluorescence emissions of dyads 1-3
and reference compounds 6 and 9 in CH2Cl2 are collected in
Table 2.
Compound 9 exhibits a typical UV-vis absorption profile
of pyrrolidino-fullerene adducts with a strong absorption band
at ca. 300-330 nm, a sharp absorption band characteristic of
fullerene adducts at 430 nm, as well as a broadband around
500 nm and a longest wavelength absorption band corresponding
to the 0f0 transition at ca. 700 nm (Figure 3).24 PMI 6 used
as the reference displays a strong π-π* transition band in the
Theoretical Calculations. Quantum chemical calculations on
the three dyads 1-3 have been conducted to get further insights
of molecular structure as well as molecular orbital energies.
Geometrical optimization was performed with semiempirical
methods using PM3 parametrization with Hyperchem 7.5.
Electronic structures of optimized geometries were studied using
the Gaussian 03 package with ab initio methods at the DFT
level using the exchange correlation hybrid functional Becke3LYP
with the atomic basis 6-31G(2d,p) for all atoms. The 2,6-
diisopropylphenyl group is found to be nearly perpendicular to
the planar perylene core, thus minimizing steric hindrance
between isopropyl groups and the imide functionality (Figure
1). On the opposite part of these systems, the plane of the phenyl
spacer is oriented out of the perylene plane. In agreement with
expected values relative to the ortho, meta, or para substitution
of the phenyl group, the shortest distance between the perylene
core and C60 was determined to be 3.72, 4.51, and 5.28 Å for
dyads 1, 2, and 3, respectively. The shortest distance between
the perylene core and C60 took into account the nearest (C10)
carbon atom of the perylene.
Cyclic Voltammetry. Cyclic voltammograms (CV) of all
three dyads 1 (Figure 2), 2, and 3 show four reversible reduction
waves, with the first, third, and fourth ones corresponding to
one-electron processes, while the second one corresponds to a
two-electron process. By comparison with those of reference
compounds 6 and 9 (Table 1), the first one-electron process is
assigned to the formation of the anion radical of the C60 moiety
(C60•--PMI). This result is in agreement with theoretical
calculations of the energy levels of the HOMO and LUMO
(23) Luo, C.; Huang, C.; Gan, L.; Zhou, D.; Xia, W.; Zhuang, Q.; Zhao, Y.;
Huang, Y. J. Phys. Chem. 1996, 100, 16685–16689.
(24) Mattay, J.; Ulmer, L.; Sotzmann, A. Mol. Supramol. Photochem. 2001,
8, 637–752.
6144 J. Org. Chem. Vol. 73, No. 16, 2008

Perylene-3,4-mono(dicarboximide)-Fullerene C60 Dyads
TABLE 2. Selected Photophysical Data of Dyads 1-3 and Reference Compounds 6 and 9 in CH2Cl2 at 298 K.
absorption maxima
ꢀ (L · mol-1 · cm-1
fluorescence
b
λmax (nm)
)
λmax (nm)
Φfluo
E0-0 (eV)
1
2
3
6
9
523
519
517
507
35300
36800
37500
27200
21200
(2270, 232)
543
554
560
544
6.8 × 10-3
2 × 10-3
12 × 10-3
0.98
2.33
2.32
2.33
2.39
325
(430, 702)a
707
2.8 × 10-4
1.76
a Other absorption bands and their corresponding epsilon values. b Determined using cresyl violet as a standard (Φf ) 0.54 at 20 °C in MeOH).
∆GPET ) -0.25 eV for 2, ∆GPET ) -0.28 eV for 3).25
Photophysical investigations are underway in order to estimate
the rate of energy transfer in these systems.
Conclusion
In conclusion, the synthesis and spectroscopic studies of
C60-perylene-3,4-mono(dicarboximide) dyads are described. It
was clearly demonstrated that the PMI dye can act as a light-
harvesting antenna for C60 as previously shown for C60-PDI
dyads. Whereas in the latter case the first reduction potentials
of C60 and PDI are very close one to each other, the first
reduction process unambiguously occurs on the C60 moiety in
the C60-PMI dyads. Such C60-PMI dyads absorb strongly in
the visible range and could be good candidates for the
development of efficient bulk-heterojunction photovoltaic de-
vices by mixing with a p-type polymer donor.
FIGURE 3. Absorption and fluorescence emission spectra of dyad 1
(bold line; λexc ) 485 nm) and reference compounds 6 (full line; λexc
) 485 nm) and 9 (dotted line; λexc ) 325 nm) in CH2Cl2 at 298 K (c
< 10-6 M).
Experimental Section
visible range (corresponding to the 0f0 band at λabs ) 507 nm
and the comparably intense 0f1 band at λabs ) 484 nm) as
well as a very weak structured band at 355 nm and a last band
(not shown) centered at 264 nm (Figure 3). Dyads 1-3
absorption spectra are composed of two distinct broad bands
with the strong absorption of the C60 moiety in the UV range
and the π-π* transition band of the PMI moiety in the UV
and visible range at ca. 520, 500, and 320 nm with high
extinction coefficients (Figure 3). The orientation of C60 toward
PMI (ortho, meta, or para substitution pattern) seems to have
no influence on the ground state as the three corresponding
dyads have nearly the same absorption features.
Emission spectra of dyads 1-3 are characterized by a strong
band corresponding to the 0f0 transition at ca. 540-560 nm.
This band presents a shoulder at 570 nm which is attributed to
the 1f0 transition band of the PMI emission. Another weak
band around 700 nm characteristic of the 0f0 transition
emission of fullerene was observed (Figure 3). An important
quenching of fluorescence of the PMI moiety (superior to
98.5%) was observed in dyads 1-3 when compared to the
fluorescence of compound 6. This process must be intramo-
lecular as the quantum yield of PMI 6 was not affected using
a stoichiometric mixture of PMI 6 and fullerene 9 in concentra-
tion similar to the case of dyad 1-3. By selectively exciting
the PMI moiety in dyad 1, at 525 nm, an emission from
1C60*-PDIwasstillobserved,givingevidenceofasinglet-singlet
energy transfer from the PMI moiety to C60 moiety. This is in
agreement with the energy levels of both units (2.39 eV for 6
and 1.76 eV for 9). Competition with reductive electron transfer
process can not be ruled out as the corresponding free energy
∆GPET was found negative using the calculated “Gibbs energy
of photoinduced electron transfer” (∆GPET ) -0.32 eV for 1,
General Procedure for 1,3-Dipolar Cycloaddition. To a solution
of N-(2,6-diisopropylphenyl)-9-(2-formylphenyl)perylene-3,4-di-
carboximide 8o (100 mg; 0.17 mmol) in anhydrous toluene (50
mL) were added C60 (185 mg; 0.26 mmol) and N-methylglycine
(sarcosine) (30 mg; 0.34 mmol). The reaction mixture was refluxed
under nitrogen for 24 h. After the solution was cooled to room
temperature, the solvent was removed under reduced pressure and
the residue was purified by column chromatography on silica gel.
After elution with CS2 to remove excess and unreacted C60, dyad
PMI-C60 1 was isolated as a reddish powder using CH2Cl2 as the
eluent (113 mg, 50% yield).
N-(2,6-Diisopropylphenyl)-9-[2-(N-methyl-3,4-fulleropyrrolidi-
nyl)phenyl]perylene-3,4-dicarboximide 1. 1H NMR (CS2/CDCl3 3:1,
3
3
500 MHz) δ (ppm) 8.70 (d, J ) 8 Hz, 1H), 8.66 (d, J ) 8 Hz,
1H), 8.61 (d, 3J ) 8 Hz, 1H), 8.56 (d, 3J ) 8 Hz, 1H), 8.42 (d, 3J
3
3
) 8 Hz, 1H), 8.36 (d, J ) 8 Hz, 1H), 8.24 (d, J ) 8 Hz, 1H),
3
3
7.76-7.70 (m, 2H), 7.66 (t, J ) 8 Hz, 1H), 7.52 (dt, J ) 8 Hz
and 4J ) 1 Hz, 1H), 7.48 (d, 3J ) 8 Hz, 1H), 7.40 (dd, 3J ) 8 Hz
4
3
3
and J ) 1 Hz, 1H), 7.34 (d, J ) 8 Hz, 1H), 7.33 (t, J ) 8 Hz,
3
3
1H), 7.30 (d, J ) 8 Hz, 1H), 4.76 (d, J ) 9.4 Hz, 1H), 4.66 (s,
2
3
1H), 3.82 (d, J ) 9.4 Hz, 1H), 2.77 (s, 3H), 2.73 (hept, J ) 7
3
Hz, 2H), 1.19, 1.17, 1.16, 1.14 (4 d, J ) 7 Hz, 12H); IR (KBr,
cm-1) ν 2964, 2929, 1703, 1657, 1582, 1358, 1092, 1022, 977,
810 cm-1; MS (MALDI-TOF, dithranol) 1332 (M)+•, 612 (M -
C60); HR-MS (ESI) calcd for C103H37N2O2 1333.2855, found
1333.2851.
N-(2,6-Diisopropylphenyl)-9-[3-(N-methyl-3,4-fulleropyrrolidi-
1
nyl)phenyl]perylene-3,4-dicarboximide 2. yield ) 25%; H NMR
(CS2/CDCl3 3:1, 500 MHz) δ (ppm) 8.60 (d, 3J ) 8 Hz, 1H), 8.59
(d, 3J ) 8 Hz, 1H), 8.51 (br d, 3J ) 8 Hz, 1H), 8.48 (d, 3J ) 8 Hz,
1H), 8.44 (d, 3J ) 8 Hz, 1H), 8.42 (br d, 3J ) 8 Hz, 1H), 8.30-7.80
3
(br m, 3H), 7.66-7.54 (br m, 3H), 7.51 (br d, J ) 8 Hz, 1H),
3
3
7.42 (t, J ) 7.5 Hz, 1H), 7.31 (s, 1H), 7.27 (d, J ) 8 Hz, 1H),
(25) Rehm, D.; Weller, A. Isr. J. Chem 1970, 8, 259–271.
J. Org. Chem. Vol. 73, No. 16, 2008 6145

Baffreau et al.
2
2
5.08 (s, 1H), 5.01 (br d, J ) 9.5 Hz, 1H), 4.34 (d, J ) 9.5 Hz,
1H), 2.92 (br s, 3H), 2.69 (hept, 3J ) 7 Hz, 2H), 1.15 and 1.16 (2
under ultrasound for 13 h. After being cooled to room temperature,
the solution was poured in water (50 mL) and extracted with CH2Cl2
(3 × 30 mL). The combined organic phases were washed with water
(2 × 30 mL), dried over MgSO4, and concentrated under reduced
pressure. The residue was purified by column chromatography on
silica gel by using CH2Cl2 as the eluent affording compound 8o as
a reddish powder (29 mg; 55% yield).
d, J ) 7 Hz, 12H); IR (KBr, cm-1) ν 2964, 2929, 1702, 1651,
3
1571, 961, 810 cm-1; MS (MALDI-TOF, dithranol) 1333 (M +
H)+, 612 (M - C60); HR-MS (ESI) calcd for C103H37N2O2
1333.2855, found 1333.2848.
N-(2,6-Diisopropylphenyl)-9-[4-(N-methyl-3,4-fulleropyrrolidi-
1
nyl)phenyl]perylene-3,4-dicarboximide 3. yield ) 35%; H NMR
N-(2,6-Diisopropylphenyl)-9-(2-formylphenyl)perylene-3,4-dicar-
(CS2/CDCl3 3:1, 500 MHz) δ (ppm) 8.60 (d, 3J ) 8 Hz, 2H), 8.50
1
boximide 8o. yield ) 94%; H NMR (CDCl3, 500 MHz) δ (ppm)
3
3
3
(d, J ) 8 Hz, 1H), 8.47 (m, 3H), 8.01 (broad s, 2H), 7.87 (broad
9.78 (s, 1H), 8.68 (d, J ) 8 Hz, 1H), 8.66 (d, J ) 8 Hz, 1H),
d, 1H), 7.62-7.55 (m, 4H), 7.42 (t, 3J ) 8 Hz, 1H), 7.27 (d, 3J )
3
3
3
8.53 (d, J ) 8 Hz, 1H), 8.50 (d, J ) 8 Hz, 1H), 8.49 (d, J ) 8
Hz, 1H), 8.47 (d, 3J ) 8 Hz, 1H), 8.17 (dd, 3J ) 7.5 Hz and 4J )
1 Hz, 1H), 7.78 (dt, 3J ) 7.5 Hz and 4J ) 1 Hz, 1H), 7.67 (t, 3J )
2
8 Hz, 1H), 7.26 (s, 1H), 5.10 (s, 1H), 5.06 (d, J ) 9.2 Hz, 1H),
2
3
4.37 (d, J ) 9.2 Hz, 1H), 2.96 (s, 3H), 2.69 (hept, J ) 7 Hz,
2H), 1.16 (d, J ) 7 Hz, 12H); 13C NMR (CS2/CDCl3 (3:1)) δ
3
3
3
7.5 Hz, 1H), 7.61 (d, J ) 8 Hz, 1H), 7.59 (d, J ) 8 Hz, 2H),
3
3
3
(ppm) 144.86, 144.44, 144.28, 144.12, 144.03, 142.91, 142.78,
142.45, 142.37, 142.34, 142.29, 141.95, 141.89, 141.88, 141.79,
141.67, 141.66, 141.51, 141.43, 141.32, 140.01, 139.98, 139.74,
139.70, 139.12, 136.96, 136.76, 136.72, 136.21, 135.71, 135.41,
132.37, 131.57, 130.77, 130.25, 130.09, 129.27, 128.97, 128.80,
128.52, 128.23, 128.04, 126.87, 126.65, 123.60, 123.53, 123.18,
121.05, 120.98, 120.21, 119.98, 83.00, 76.87, 69.83, 68.67, 39.86,
29.83, 28.96, 23.81; IR (KBr, cm-1) ν 2930, 1703, 1657, 1545,
1358, 969 cm-1; MS (MALDI-TOF, dithranol) 1331 (M - H)+,
612 (M - C60); HR-MS (ESI) calcd for C103H37N2O2 1333.2855,
found 1333.2837.
7.53 (d, J ) 7.5 Hz, 1H), 7.49 (t, J ) 8 Hz, 1H), 7.36 (d, J )
3
3
8 Hz, 2H), 2.74 (hept, J ) 7 Hz, 2H), 1.20 (d, J ) 7 Hz, 12H);
13C NMR (CDCl3) δ (ppm) 191.43, 163.91, 145.73, 145.68, 142.97,
138.69, 137.29, 137.05, 134.87, 133.98, 133.83, 132.07, 132.05,
131.58, 130.98, 130.48, 129.61, 129.46, 129.23, 128.86, 128.81,
128.05, 127.73, 126.93, 124.05, 124.04, 124.00, 122.93, 121.35,
121.29, 120.65, 120.47, 29.69, 29.15, 24.02; IR (KBr, cm-1) ν 2964,
2933, 1702, 1657, 1593, 1571, 1359, 1092, 1023, 810 cm-1; MS
(MALDI-TOF, dithranol) 586 (M)+•.
N-(2,6-Diisopropylphenyl)-9-(3-formylphenyl)perylene-3,4-dicar-
boximide 8m. 86% yield for classical procedure and 63% yield
using ultrasound conditions; 1H NMR (CDCl3, 500 MHz) δ (ppm)
N-(2,6-Diisopropylphenyl)-9-bromoperylene-3,4-dicarboxim-
ide 7. N-(2,6-Diisopropylphenyl)perylene-3,4-dicarboximide (5 g,
10.5 mmol) were dissolved in chlorobenzene (500 mL). Bromine
(2.40 mL, 47.5 mmol) was added, and the reaction mixture was
stirred for 5 h at 50 °C. Unreacted bromine was removed using
nitrogen flow, and chlorobenzene was removed under reduced
pressure. The residue was purified by column chromatography on
silica gel using CH2Cl2 as the eluent affording compound 7 (4.8 g;
83% yield) and the 1,6,9-tribromoperylene-3,4-dicarboximide de-
rivative (1.28 g; 17%) as reddish powders. Both compounds were
recrystallized using CHCl3/methanol as the mixture of eluents: 1H
3
3
10.16 (s, 1H), 8.69 (d, J ) 8 Hz, 1H), 8.67 (d, J ) 8 Hz, 1H),
3
3
3
8.54 (d, J ) 8 Hz, 1H), 8.51 (d, J ) 8 Hz, 1H), 8.50 (d, J ) 8
Hz, 1H), 8.49 (d, 3J ) 8 Hz, 1H), 8.08 (s, 1H), 8.03 (d, 3J ) 8 Hz,
3
3
3
1H), 7.90 (d, J ) 8 Hz, 1H), 7.84 (d, J ) 8 Hz, 1H), 7.75 (t, J
3
3
) 8 Hz, 1H), 7.63 (t, J ) 8 Hz, 1H), 7.62 (d, J ) 8 Hz, 1H),
7.49 (t, 3J ) 8 Hz, 1H), 7.35 (d, 3J ) 8 Hz, 2H), 2.78 (hept, 3J )
7 Hz, 2H), 1.19 (d, J ) 7 Hz, 12H); 13C NMR (CDCl3) δ (ppm)
3
191.99, 163.96, 145.72, 141.56, 140.87, 137.51, 137.24, 136.77,
135.85, 132.47, 132.08, 131.01, 130.93, 130.51, 129.58, 129.46,
129.41, 129.37, 129.20, 128.68, 128.39, 127.41, 126.93, 124.02,
123.40, 121.14, 120.52, 120.34, 29.14, 24.01; IR (KBr, cm-1) ν
2972, 1702, 1657, 1545, 1360, 969, 814, 749 cm-1; MS (MALDI-
TOF, dithranol) 586 (M)+•.
3
NMR (CDCl3, 500 MHz) δ (ppm): 8.68 (d, J ) 7 Hz, 1H), 8.65
3
3
3
(d, J ) 7 Hz, 1H), 8.56 (d, J ) 8 Hz, 1H), 8.50 (d, J ) 8 Hz,
1H), 8.45 (d, 3J ) 8 Hz, 1H), 8.36 (d, 3J ) 8 Hz, 1H), 8.30 (d, 3J
3
3
) 8 Hz, 1H), 7.96 (d, J ) 8 Hz, 1H), 7.76 (t, J ) 8 Hz, 1H),
7.50 (t, 3J ) 8 Hz, 1H), 7.35 (d, 3J ) 8 Hz, 2H), 2.74 (hept, 3J )
7 Hz, 2H), 1.18 (s, 3J ) 7 Hz, 12H); IR (KBr, cm-1) ν 2976, 1701,
1659, 1591, 1562, 1359, 1247, 837, 805, 751 cm-1; MS (MALDI-
TOF, dithranol) 560/562 (M + H)+.
N-(2,6-Diisopropylphenyl)-9-(4-formylphenyl)perylene-3,4-dicar-
boximide 8p. 88% yield for classical procedure and 73% yield using
ultrasound conditions; 1H NMR (CDCl3, 500 MHz) δ (ppm) 10.14
(s, 1H), 8.70 (d, 3J ) 8 Hz, 1H), 8.69 (d, 3J ) 8 Hz, 1H), 8.55 (t,
3J ) 8 Hz, 1H), 8.54 (d, 3J ) 8 Hz, 1H), 8.52 (d, 3J ) 8 Hz, 1H),
3
3
3
N-(2,6-Diisopropylphenyl)-1,6,9-tribromoperylene-3,4-dicarbox-
8.51 (d, J ) 8 Hz, 1H), 8.09 (d, J ) 8 Hz, 2H), 7.94 (d, J ) 8
Hz, 1H), 7.74 (d, 3J ) 8 Hz, 2H), 7.64 (t, 3J ) 8 Hz, 2H), 7.49 (t,
imide. 1H NMR (CDCl3, 500 MHz) δ (ppm) 9.40 (d, 3J ) 7.5 Hz,
3
3J ) 8 Hz, 1H), 7.35 (d, J ) 8 Hz, 2H), 2.77 (hept, J ) 7 Hz,
3
3
1H), 9.10 (d, J ) 7.5 Hz, 1H), 8.98 and 8.97 (2 s, 2H), 8.45 (d,
3J ) 8 Hz, 1H), 8.00 (d, 3J ) 8 Hz, 1H), 7.80 (t, 3J ) 8 Hz, 1H),
7.50 (t, 3J ) 7 Hz, 1H), 7.35 (d, 3J ) 7 Hz, 2H), 2.75 (hept, 3J )
7 Hz, 2H), 1.20 (d, 3J ) 7 Hz, 12H); MS (MALDI-TOF, dithranol)
719 (M + H)+.
2H), 1.19 (d, J ) 7 Hz, 12H); 13C NMR (CDCl3) δ ) 191.75,
3
163.91, 146.09, 145.68, 141.64, 137.41, 137.11, 135.80, 132.23,
132.03, 132.02, 130.96, 130.71, 130.44, 129.95, 129.53, 129.45,
129.33, 128.66, 128.36, 128.23, 127.40, 126.86, 124.03, 124.00,
123.30, 121.17, 121.13, 120.50, 120.34, 29.13, 23.98; IR (KBr,
cm-1) ν 2972, 2929, 1703, 1657, 1579, 1360, 969 cm-1; MS
(MALDI-TOF, dithranol) 586 (M)+•.
General Procedure for the Suzuki Cross-Coupling Reaction.
Classical Conditions. To a solution of compound 7 (100 mg; 0.17
mmol) in dry 1,2-dimethoxyethane (DME or glyme) (20 mL) were
added under nitrogen 2-formylphenylboronic acid (32 mg; 0.22
mmol) and potassium phosphate tribasic (K3PO4) (100 mg; 0.47
mmol) followed by Pd(PPh3)4 (20 mg; 16 µmol). The reaction
mixture was refluxed for 15 h. After being cooled to room
temperature, the solution was poured into water (50 mL) and
extracted with CH2Cl2 (3 × 30 mL). The combined organic phases
were washed with water (2 × 30 mL), dried over MgSO4, and
concentrated under reduced pressure. The residue was purified by
column chromatography on silica gel by using CH2Cl2 as the eluent
affording compound 8o as a reddish powder (98 mg; 94% yield).
Under Ultrasound Conditions. To a solution of compound 7
(50 mg; 0.089 mmol) in dry DME (10 mL) were added under
nitrogen 2-formylphenylboronic acid (16 mg; 0.11 mmol) and
potassium phosphate tribasic (K3PO4) (46 mg; 0.22 mmol) followed
by Pd(PPh3)4 (12 mg; 10 µmol). The reaction mixture was stirred
N-Methyl-2-phenyl-3,4-fulleropyrrolidine 9. To a solution of
C60 (100 mg; 0.14 mmol) in dry toluene (100 mL) were added
benzaldehyde (20 µL; 0.2 mmol) and sarcosine (13 mg; 0.15 mmol).
The reaction mixture was stirred at 90 °C for 8 h under nitrogen.
After being cooled to room temperature, the solution was concen-
trated under reduced pressure. The residue was purified by column
chromatography on silica gel by using CS2 as the eluent to afford
compound 9 as a black powder (47 mg; 40% yield): 1H NMR (CS2/
CDCl3 3:1), 500 MHz) δ (ppm) 7.78 (br m, 1H), 7.41 (t, 3J ) 7.5
Hz, 1H), 7.33 (t, 3J ) 7.5 Hz, 1H), 7.18 (d, 3J ) 7.5 Hz, 1H), 7.10
(d, 3J ) 7.5 Hz, 1H), 4.99 (d, 2J ) 9.5 Hz, 1H), 4.94 (s, 1H), 4.29
2
(d, J ) 9.5 Hz, 1H), 2.84 (s, 3H); IR (KBr, cm-1) ν 2933, 1073,
1023, 969, 702 cm-1; MS (MALDI-TOF, dithranol) 852 (M - H)+.
Steady-State Spectroscopy. All solvents used are spectroscopic
grade and were used as commercially available. Electronic absorp-
6146 J. Org. Chem. Vol. 73, No. 16, 2008

Perylene-3,4-mono(dicarboximide)-Fullerene C60 Dyads
tion spectra were recorded with a Lambda 19 NIR model from
Perkin-Elmer. Fluorescence spectra were recorded in nondeoxy-
genated solvents at 20 °C with a QM-4/QuantaMaster fluorometer
from PTI equipped with rapid monochannel detection and continu-
ous excitation source. Quantum yields were determined using cresyl
violet as a standard reference (Φf ) 0.54 at 20 °C in MeOH).26
Cyclic Voltammetry. Cyclic voltammetry was performed in a
three-electrode cell equipped with a platinum millielectrode and a
platinum wire counter-electrode. A silver wire served as pseudo-
reference electrode, and its potential was checked against the
ferricinium/ferrocene couple (Fc+/Fc) before and after each experi-
ment. The electrolytic media involved CH2Cl2 (HPLC grade),
o-dichlorobenzene (Aldrich spectroscopic grade), and 0.1 M of
tetrabutylammonium hexafluorophosphate (TBAHP, puriss quality).
All experiments were performed in a glovebox containing dry,
oxygen-free (<1 ppm) argon, at room temperature. Electrochemical
experiments were carried out with an EGG PAR 273A potentiostat.
Acknowledgment. This work was supported by the French
National Research Agency (ANR Nanorgysol) and the Conseil
Ge´ne´ral du Maine et Loire (PhD grant to J.B.). We thank BASF-
AG Ludwigshafen for providing N-(2,6-diisopropylphenyl)-
perylene-3,4-mono(dicarboximide).
Supporting Information Available: Spectroscopic and pho-
tophysical data for all new molecules synthesized, CVs of dyads
1-3, and reference numbers 6 and 9. This material is available
free of charge via the Internet at http://pubs.acs.org.
(26) Magde, D.; Brannon, J. H.; Cremers, T. L.; Olmsted, J. J. Phys. Chem.
1979, 83, 696–699.
JO800804Z
J. Org. Chem. Vol. 73, No. 16, 2008 6147