D/A cruciform bithiophene chromophores as potential molecular scaffolds for optoelectronic applications

Article abstract of DOI:10.1016/j.tet.2016.01.038

Thiophene-based molecular semiconductors are of high interest in the development of optoelectronics devices and are extensively used. So far, structural variations have been widely performed on linear molecular push-pull in order to optimize their photoph

Full text of DOI:10.1016/j.tet.2016.01.038

Accepted Manuscript
D/A cruciform bithiophene chromophores as potential molecular scaffolds for
optoelectronics applications
Hecham Aboubakr, Chandrasekar Praveen, Volodymyr Malytskyi, René Sawadogo,
Jean-Marc Sotiropoulos, Lénaïk Belec, Hugues Brisset, Jean-Manuel Raimundo
PII:
S0040-4020(16)30038-2
10.1016/j.tet.2016.01.038
TET 27445
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 24 October 2015
Revised Date: 17 January 2016
Accepted Date: 19 January 2016
Please cite this article as: Aboubakr H, Praveen C, Malytskyi V, Sawadogo R, Sotiropoulos J-M, Belec L,
Brisset H, Raimundo J-M, D/A cruciform bithiophene chromophores as potential molecular scaffolds for
optoelectronics applications, Tetrahedron (2016), doi: 10.1016/j.tet.2016.01.038.
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D/A cruciform bithiophene chromophores as potential
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Hecham Aboubakr, Chandrasekar Praveen, Volodymyr Malytskyi, René Sawadogo, Jean-Marc Sotiropoulos,
Lénaïk Belec, Hugues Brisset,* Jean-Manuel Raimundo*

1
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Tetrahedron
journal homepage: www.elsevier.com
D/A cruciform bithiophene chromophores as potential molecular scaffolds for
optoelectronics applications.
Hecham Aboubakr,a Chandrasekar Praveen,a Volodymyr Malytskyi,a René Sawadogo,c Jean-Marc
Sotiropoulos,c Lénaïk Belec,b Hugues Brisset,b* Jean-Manuel Raimundoa*
a Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), CNRS UMR 7325, Aix Marseille Université, 13288 Marseille Cedex 09, France.
bLaboratoire Matériaux Polymères-Interfaces-Environnement Marin (MAPIEM - EA 4323), Université de Toulon, SeaTech, BP 20132, 83957La Garde Cedex,
France.1
cUniversité de Pau et des Pays de l’Adour, UMR 5254 IPREM Hélioparc 2 avenue Président Angot 64053 Pau cedex, France.
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
Thiophene-based molecular semiconductors are of high interest in the development of
optoelectronics devices and are extensively used. So far, structural variations have been
widely performed on linear molecular push-pull in order to optimize their photophysical
properties while 2D systems are quite limited. We report herein the synthesis of four new
chromophores based on bithiophene core end-capped with dibutylaminostyryl groups and
functionalized on the 3,3’ position with different electron withdrawing groups. Optical and
electrochemical characterizations have been performed as well as theoretical calculations
Available online
that corroborate the experimental data
.
Keywords:
Thiophene
Push-pull chromophore
Optoelectronics
2015Elsevier Ltd. All rights reserved
.
———
* Corresponding authors: (JMR) Phone +33.6.29.41.39.25, Fax. +33.4.91.41.89.16, E-mail: jean-manuel.raimundo@univ-amu.fr (HB) Phone
+33.4.94.14.67.24, Fax.+33.4.94.14.27.86, E-mail:brisset@univ-tln.fr.
1

2
Tetrahedron
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1. Introduction
PPTS resulted in the successful protection of aldehyde group and
subsequent dimerization led to the protected dimer 7 in 43%
yield as reported in literature.18 Formylation of 7 was achieved by
treating with 2 equiv of n-BuLi, followed by the addition of DMF
and subsequent hydrolysis afforded 3,3’-(1,3-dioxolane)-5,5’-
diformyl-2,2’-bithiophene 6 in 68% as yellow powder (Scheme
The design and synthesis of organic materials that can be used as
an alternative to silicon based optoelectronic devices has
tremendously increased over the last two decades.1 Indeed,
organic materials offer the advantage to be produced through out
low-cost solution technologies such as spin coating, inkjet
printing or roll-to-roll processes associated with lower
environmental impact.2 For the main foreseen applications,
namely light-emitting diodes (OLEDs),3 field-effect transistors
(OFETs)4,5 and photovoltaics (OPVs),6,7,8 reproducible effective
organic semiconductors are desired. Therefore, design of
innovative and optimized target-specific semiconductors is
strongly recommended in order to optimize their performance
and lifetime. To achieve this goal, organic semiconductors need
to fulfill peculiar structural and molecular criteria that depend on
the focused applications.9,10,11 For instance, molecular packing,
charge carrier mobility and transport, energy gap and levels,
solution-processability, molar extinction coefficients are some of
the important parameters that plays key role on the mentioned
devices performances.
1). Then, Wittig olefination of
6
with 4-(N,N-
dibutylbenzyl)triphenylphosphonium iodide19 led to compound 5
which in turn was treated with PPTS in acetone to afford the bis-
aldehyde 4 in 93% yield. The target compounds 1 and 2 were
obtained in 53 and 52% yield by Knoevenagel condensation of 4
with malonodinitrile and diethylthiobarbituric acid, respectively.
Compound 3 was prepared by through Wittig olefination of 4
with the p-nitrobenzyltriphenylphosphonium bromide salt. All
chromophores were obtained as dark or dark-blue/green powders
and have been thoroughly characterized by H NMR, 13C NMR,
mass spectrometry, and elemental analysis.
1
C4H9
N
C4H9
I
O
O
PPh3
O
O
O
S
n-BuLi, DMF
S
t-BuOK, 1,2-DCE, 80°C
S
S
96%
68%
O
O
O
O
Until recently, most of the efforts have been concentrated almost
on polymers with respect to their better film quality compared to
small molecules. However, small molecules have gained
increased interests to overcome some drawbacks of polymer
technology i.e. their difficulties of purification, low
reproducibility in synthesis and weakness in determining
structure-properties relationships. Additionally, small molecules
have also the benefits both to be chemically and specifically
modified to fine tune their optoelectronic properties. For
example, judicious choice of appropriate conjugated units (such
as heteroaromatic cores) and incorporation of electron-donating
or electron withdrawing and side chains in the molecules serve to
adjust the HOMO/LUMO energy levels and control the HOMO–
LUMO bandgap.12
O
6
7
C4H9
N
C4H9
O
O
S
S
O
O
p-toluenesulfonate
C4H9
C4H9
N
acetone
N
5
C4H9
C4H9
O
93%
S
S
O
C4H9
N
4
C4H9
NO2
NO2
C4H9
N
C4H9
Our longstanding interest in controlling the electronic properties
and continuing efforts on synthesis of new organic semi-
conductors for optoelectronic applications have led us to use a
novel interesting scaffold, as spacer, based on the 2,2’-
bithiophene core.13,14,15,16,17 The new functionalized spacer
permits an iterative functionalization selectively on the 3,3’ and
5,5’ positions allowing us the possibility to synthetize
asymmetric compounds with donors and acceptors groups (Chart
1). This will be very helpful to gain further insights into the
structure-properties relationships for the above applications.
3
PPh3, Br
S
S
t-BuOK, CH2Cl2, rt
C4H9
N
28 %
C4H9
NO2
C4H9
N
NC
C4H9
N
N
CN
2
S
CH2Cl2,
ethylenediammonium
diacetate, rt
S
NC
C4H9
NO2
N
C4H9
S
CN
N
52%
C4H9
N
O
C4H9
N
N
C4H9
C4H9
O
S
S
S
S
N
C4H9
N
S
S
O
O
N
N
N
C4H9
1
3
C4H9
C4H9
C4H9
N
C4H9
N
N
O
O
O
O
1
S
N
CH2Cl2,
S
NO2
S
ethylenediammonium
diacetate, rt
53%
O
N
C4H9
N
C4H9
N
C4H9
NC
N
C4H9
C4H9
O
S
O
C4H9
CN
2
N
S
S
S
S
Scheme 1. Synthetic pathway of chromophores 1-4.
O
4
C4H9
NC
N
C4H9
N
C4H9
CN
Crystallographic structure
C4H9
Chart 1. Structure of new D/A cruciform bithiophene chromophores 1-4.
Unexpectedly, the crystallographic structure of single crystal
of (C 2/c space group) exhibits a syn conformation, with a
dihedral angle of 41.55° between the two thiophene-
diaminostyryl moieties that are coplanar (Figure ). In the
4
2. Results and discussion
Synthesis
1
crystal lattice, each molecule shows eight interactions with
four other neighboring molecules. Thus, a half molecule
presents both two C-C interactions with a neighboring
The core skeleton has been prepared from commercially
available thiophene-3-carboxaldehyde in 3 steps. First, reacting
thiophene-3-carboxaldehyde with 1,2-ethandiol in presence of
2

3
compound and two O-H interactions with another.
Examination of the C-C (3.327Å) and O-H (2.517Å)
distances shows that these distances are significantly shorter
than the sum of the Van der Waals radii, which evidences
the occurrence of strong intramolecular interactions.
Respectively a C-C interaction was found between the C of
the aromatic ring bearing the dibutylamino group and the C
of the carbonyl group of another molecule and inversely. In
addition, O-H interactions are formed between the nearest
ethylenic H beside the thiophene and the O of the carbonyl
group from a neighboring molecule and vice versa. All these
interactions can be found in number and length on the
the use of more bulky acceptors (Figure 2). The deviation from
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the planarization of the π-conjugated system contributes to a
diminution of the effective conjugation leading to
a
hypsochromic shift of the maximum of absorption. Furthermore,
the observed blue shift might be ascribed to the syn- or trans-
conformation of the bithiophene core, as shown in the ORTEP
view of 4 (Figure 1).
Molecular structure and electronic properties of the molecules 1-
4 were obtained thanks to DFT calculations using B3LYP and
M06 with the 6-31G (d,p) basis set (Table 2) in order to
determine the most favorable conformation. For all compounds
two minima are found on the potential energy surface closed in
energies (B3LYP: from 0.5 to 1 kcal/mol and M06: from 0.5 to 5
kcal/mol). The anti conformers of the compounds 2 and 3 are
slightly privileged (~0.8 and 0.5 kcal/mol respectively) with the
M06 functional but only the 2-anti with B3LYP (0.9 kcal/mol).
For 1 and 4, both functional calculations found the syn
conformations slightly more stable than the anti ones (B3LYP:
0.73 and 0.46 kcal/mol; M06: 4.98 and 1.59 kcal/mol
respectively). We can note that considering solvent effect using
the continuum solvation model with B3LYP, the relative
stabilities of syn and anti isomers 1 and 4 remain the same but
are reversed for 2 and 3.
second half part of the molecule 4.
Figure 1. ORTEP view of compound 4 (black: C; blue: N; green: S and red:
O, for clarity H are omitted).
All these results show the importance of crystal effect on the
structure found experimentally. Nevertheless, It is noteworthy,
that if we consider the compound 4, theoretical structural
calculations in the gas phase are in good agreement with
experimental results (vide supra). In fact, we calculated for the
syn conformer a dihedral angle around 45°. Both functionals
show that all HOMO levels are located along the π-conjugated
system where as the LUMO levels are mainly centralized on the
bithiophene core and lateral acceptor groups (Table 2). The
energy values of these frontier orbitals can be correlated with the
cyclic voltammetry experiments.
Optical properties of the chromophores 1-4 have been
investigated by UV-Visible spectroscopy in CHCl3. It was
anticipated that replacing the CHO group by a stronger acceptor
could contribute to
a hypso/bathochromic shift of the
corresponding chromophores. Thus as expected, malonodinitrile
substitution in 2 leads to a 147 nm bathochromic shift of the
maximum of absorption compared to the parent compound 4.
Nevertheless,
changing
the
malonodinitrile
to
4-
vinylnitrobenzene 3 or 1,3-diethylthiobarbituric 1 acceptors
induces a more or less pronounced hypsochromic shift of the
maximum of absorption (Table 1 and Figure 2).
Table 2. DFT structure for compound 4 and corresponding frontier Kohn
Sham molecular orbitals. HOMO/LUMO calculated values in eV for 1-4
compounds (B3LYP/6-31G(d,p))
x 2.5
4-anti conformation
4-syn conformation
1
1
2
3
4
0
300
400
500
600
(nm)
700
800
LUMO
LUMO
λ
Figure 2. UV-Vis spectra of chromophores 1-4 in in CHCl3 (C = 10-5 M).
Table 1. Absorption maximum (λabs nm) and molar extinction coefficient (log
ε L.mol-1.cm-1) of compounds 1-4.
1
2
3
4
λabs
logε
λabs
logε
λabs
logε
λabs
logε
HOMO
Syn conformation
HOMO
302
381
425
4.43
4.15
4.08
348
399
4.59
4.34
327
414
600
4.54
4.81
4.09
256
374
453
4.83
5.03
4.90
Anti conformation
HOMO
-4.788
-5.026
-4.730
-4.756
LUMO
-2.833
-2.941
-2.518
-2.113
HOMO
-4.785
-4.995
-4.563
-4.749
LUMO
1
2
3
4
-2.995
-3.073
-2.523
-2.120
These observations suggest that the π-conjugated system, for
compounds 1 and 3, undergoes a twist compared to the more
planar chromophore 4 because of the steric hindrance induced by
3

4
Tetrahedron
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for compound 3. The differences at low temperatures can be
Cyclic voltammograms (CV) of chromophores 2-4 are
characterized by one reversible one-electron oxidation redox
system corresponding to the formation of the radical cation while
the CV of the compound 1 exhibits a second oxidation redox
system ascribed to a more constrained π-conjugated system
(Figure 3 - Table 3). All compounds display similar value for
E1/2(ox1), except the compound 3 which shows a lowest oxidation
potential, attributed to an extended π-system, and correlates with
the DFT calculations (Table 2). Compound 2 has a reduction
potential shifted to more positive value attributed to a stronger
acceptor character of the dicyanomethylene (DCN) groups
compared to the aldehyde groups of the derivative 4. However,
replacement of the DCN groups by a stronger acceptor such as
1,3-diethylthiobarbituric acid (1) doesn’t lead to a lowered
reduction potential. These observations suggest that both
geometric and/or steric parameters as well as the nature of the
acceptors contribute to these strong changes. Nevertheless a
roughly good correlation is found, for the reduction potentials,
between experimental values and LUMO position calculated by
DFT (B3LYP); (E1/2(red1)/ELUMO calculated): 4 (-1.79/-2.11), 1 (-
1.60/-2.83), 3 (-1.53/-2.52), 2 (-1.18/-3.07) assuming the most
stable syn or anti conformations for each compounds. Moreover,
the comparison between the calculated and the electrochemcial
bandgap are in good agreement with the same tendency.
attributed to the lateral groups nature and/or to impurities
resulting from synthesis. Concerning compounds 2 and 4, the
high degradation temperatures are rather consistent with the first
hypothesis, the difference being attributed to bond energies in
lateral groups. Indeed, compound 2 lateral group involves C-C
bonds (C=C(CN)2) which are not present in compound 4 (C=O).
Above 300°C, the degradation steps for compound 1 and 3 are
almost twice of those compounds 2 and 4. At these temperatures,
chemical bonds such as C-N and C-C bonds can be broken,
releasing lateral groups of compound 1. NO2 groups and lateral
cycles of compound 3 are probably released in the same
temperature range.
Table 3. Redox potentials (V) for compounds 1-4 vs Fc/Fc+ and
electrochemical (Eg(Elec)), calculated (Eg(Cal)), optical (Eg(Opt)) bandgaps in eV.
1
2
0.25
-
-1.18 V
1.43
1.92
2.57
3
0.09
-
-1.53 V
1.61
2.04
2.48
4
0.22
-
-1.79 V
2.01
2.64
2.27
E1/2 (Ox1) V
E1/2 (Ox2) V
E1/2 (Red1) V
Eg(Elec) eV
0.17
0.65
-1.60
1.77
1.95
2.36
Figure 4. TGA curves of compounds 1 to 4 in nitrogen with a heating rate of
20 °C/min.
3. Conclusion
Eg(Cal) eV
Eg(Opt) eV
We have reported the synthesis of four novel DAAD
chromophores having a bithiophene core end-capped with
dibutylaminostyryl as a donor group and functionalized with four
different acceptors on the 3,3’ positions of the bithiophene core.
Interestingly, in contrast to what it was expected, two
chromophores from the studied series have shown a syn
conformation supported by the theoretical calculations as well as
by the XRD analysis of the crystal structure of compound 4.
Their acceptable electro-optical properties associated to high
thermal stabilities make them suitable for the foreseen
applications.
4. Experimental Section
Reagents
and
analysis.
Tetrahydrofuran
(THF),
dimethylformamide (DMF), chloroform (CHCl3), ethanol,
methylene chloride (CH2Cl2), cyclohexane (C6H12), anhydrous
acetone, diethylether, o-dichlorobenzene were purchased from
CarloErba. Tetrabutylammonium hexafluorophosphate (n-
Bu4NPF6) was purchased from Fluka and was used as received.
Potassium tert-butoxide (t-BuOK), crown ether 18C6, n-
butyllithium 2.5 M in hexane (n-BuLi), 4-(N,N-dibutylbenzyl)-
Figure 3. Cyclic voltammetry of compounds 1-4 at 10-3
dichlorobenzene, n-Bu4NPF6 (0.1M) scan rate 100 mV.s-1.
M in o-
triphenylphosphonium
bromide,
4-(p-
The four compounds are degraded around 500°C with the same
amount of residual char. However a great dispersion in terms of
thermal stability is observed between the four compounds (Figure
4). As shown in Figure 4, the weight loss starts from 156°C for
compound 1, whereas it only starts around 320°C for compound
4. The following decreasing thermal stability is observed:
compound 4 > compound 2 > compound 3 > compound 1. The
degradation mode is also very different. No marked steps can be
clearly detected for compound 1, whereas two steps degradation
are visible for compounds 2 and 4 and three steps can be detected
nitrobenzyl)triphenylphosphonium bromide, malonodinitrile,
pyridinium-p-toluenesulfonate (PPTS), ethylenediammonium
diacetate (EDDA), 1,3-diethylthiobarbituric acid were purchased
from Sigma-Aldrich and used as received.
Physico-chemical analyses. Melting points were obtained from
1
an Electrothermal 9100 apparatus and are uncorrected. H NMR
and 13C NMR spectra were recorded on Bruker AC 250 at 250
MHz and 62.5 MHz, respectively. High resolution mass
4

5
spectrometry (HRMS) was made with a Qstar Elite spectrometer
(Applied Biosystems SCIEX) by electrospray ionization (ESI)
method. Elemental analysis was recorded with an EA 1112 series
from ThermoFinnigan. XR-diffraction (λMoKα= 0.71073Å)
of stirring at 0 °C, 10 mg (0.26 mmol) of 18-crown-6 and 0.15
ACCEPTED MANUSCRIPT
g (0.42 mmol) of compound 6 were added. The mixture was
stirred for 24 h at room temperature and the solvent was
evaporated under reduced pressure. The crude product was
purified on a silica gel column using CH2Cl2 to give 0.31 g (96%)
of title compound as orange oil. H NMR (250 MHz, CDCl3) δ:
0.93-0.97 (t, 12H, J = 7.3 Hz, 4 x -CH2-CH2-CH2-CH3); 1.31-
under monocrystal
4 was made with a Bruker-Nonius
spectrometer.20
1
3
Physico-chemical measurements in solution. UV-visible
absorption spectra were obtained on Varian Cary 1E
spectrophotometer. The electronic absorption maxima (λmax
1.37 (m, 8H, 4 x -CH2-CH2-CH2-CH3); 1.56-1.62 (m, 8H, 4 x -
CH2-CH2-CH2-CH3); 3.26-3.31 (t, 8H, J = 7.6 Hz, 4 x -CH2-
3
a
)
CH2-CH2-CH3); 3.94-4.00 (m, 4H, 2 x O-CH2-CH2-O-); 4.11-
4.17 (m, 4H, 2 x O-CH2-CH2-O-); 5,76 (s, 2H, 2 x -CH-O); 6.61
(d, 4H, 3J = 8.5 Hz, 4 x Hbenz); 6.87 (s, 2H, 2 x Hthio); 7.11 (d, 2H,
were directly extracted from absorption spectra of compound as
chloroform solution. Cyclic voltammetry (CV) data were
acquired using a BAS 100 Potentiostat (Bioanalytical Systems)
and a PC computer containing BAS100W software (v2.3). A
three-electrode system based on a platinum (Pt) working
electrode (diameter 1.6 mm), a Pt counter electrode and an
Ag/AgCl (with 3 M NaCl filling solution) reference electrode
was used. Tetrabutylammonium hexafluorophosphate served as a
supporting electrolyte (0.1 M). All experiments were carried out
in o-dichlorobenzene (electronic grade purity) at 20 °C.
Ferrocene was used as an internal standard. Electrochemical
reduction/oxidation potential values vs Fc/Fc+ were determined
3
3J = 13.3Hz, 4 x Heth); 7.22 (d, 2H, J = 13.3 Hz, 4 x Heth); 7.31
3
(d, 4H, J = 8.5 Hz, 4 x Hbenz). 13C NMR (62.5 MHz, CDCl3) δ:
14.0 (CH3); 20.4 (CH2); 29.5 (CH2); 50.8 (CH2); 65.3 (CH2); 98.9
(CH); 111.7 (Cbenz); 116.3 (Cbenz); 123.4 (Cthio); 123.8 (Cthio);
127.8 (Cthio); 129.8 (Ceth); 129.9 (Ceth); 138.2 (Cbenz); 145.3 (Cthio);
148.0 (Cbenz). HRMS (ESI+) m/z: 769.4068 [M+H]+ (calculated:
769.4067). Elemental analysis for C46H60O4S2N2 (%), calculated:
C, 71.84; H, 7.86; S, 8.34; N, 3.64 - Found: C, 68.85; H, 7.82; S,
7.42; N, 3.57.
from the cyclic voltammogram at a concentration of 1.10-3
M
5,5'-bis((E)-4-(dibutylamino)styryl)-[2,2'-bithiophene]-3,3'-
with a scan rate of 100 mV.s-1. Thermal properties of the
compounds were explored by thermogravimetric analysis (TGA)
on a Q600 from TA instruments. The thermal stability of the
compounds was studied under 100 mL/min nitrogen flow with a
heating rate of 20 °C/min from room temperature to 800 °C. A
purge nitrogen flow of 400 mL/min was applied over a period of
20 min inside the oven before starting the experiment to remove
all oxygen from the oven.
dicarbaldehyde (4). Under an inert atmosphere, 1.50 g (1.95
mmol) of
5 and 1.96 g (7.8 mmol) of pyridinium p-
toluenesulfonate (PPTS) were dissolved in 100 mL of anhydrous
acetone. The reaction mixture was refluxed for 72 h. After
removal of the solvent under reduced pressure the crude product
was dissolved in CH2Cl2 and successively washed with NaHCO3
(1M) and brine. Organic phases were dried over anh. MgSO4 and
the solvent was removed under reduced pressure to afford 1.23 g
1
(93%) of title compound as a red solid. Mp = 172-174 °C. H
3
Computational Methodology: Calculations were carried out with
the Gaussian 09 program21 at the DFT level of theory using both
B3LYP22a-c and M0622d functionals. All the different atoms (C, N, H,
O, S) have been described with a 6-31G(d,p) double-ζ basis set.23
Geometry optimizations were carried out without any symmetry
restrictions. The nature of the minima was verified with analytical
frequency calculations, by the absence of negative eigenvalue.
NMR (250 MHz, CDCl3) δ: 0.95-1.00 (t, 12H, J = 7.3 Hz, 4 x -
CH2-CH2-CH2-CH3); 1.33-1.42 (m, 8H, 4 x -CH2-CH2-CH2-
CH3); 1.54-1.65 (m, 8H, 4 x -CH2-CH2-CH2-CH3); 3.28-3.34 (t,
3
3
8H, J = 7.7 Hz, 4 x -CH2-CH2-CH2-CH3); 6.62 (d, 4H, J = 8.7
Hz, 4 x Hbenz); 6.92 (m, 4H, 2 x Heth and 2 x Hthio); 7.35 (d, 4H, 3J
= 8.7 Hz, 4 x Hbenz); 7.42 (d, 2H, 3J = 14.1 Hz, 2 x Heth); 9.87 (s,
2H, 2 x CHO). 13C NMR (62.5 MHz, CDCl3) δ: 13.0 (CH3); 19.3
(CH2); 28.5 (CH2); 49.7 (CH2); 110.6 (Cbenz); 113.7 (Cbenz); 121.8
(Cthio); 121.9 (Cthio); 127.2 (Cthio); 131.5 (Ceth); 137.3 (Ceth); 139.6
(Cbenz); 145.6 (Cthio); 147.5 (Cbenz); 183.4 (CHO). HRMS (ESI+)
m/z: 681.3559 [M+H]+ (calculated: 681.3543). Elemental
analysis for C42H52O2S2N2 (%), calculated: C, 74.07; H, 7.70; S,
9.42; N, 4.11 - Found: C, 74.04; H, 7.83; S, 9.32; N, 3.97.
3,3'-di(1,3-dioxolan-2-yl)-[2,2’-bithiophene]-5,5'-dicarbaldehyde
(6). At 0 °C, under argon 13.82 mL of n-BuLi (34.55 mmol; 2.5
M in hexane) was added dropwise to a solution of 4.32 g (13.94
mmol) of 3,3'-(1,3-dioxolane)-2,2'-bithiophene 7 in 50 mL of
anhydrous THF. After 15 min of addition, 2.72 mL (34.82 mmol)
of anhydrous DMF was added. After 7 h of agitation at room
temperature, 100 mL of water was added and extracted thrice
with 50 mL of chloroform. After dried over anh. MgSO4,
filtration and evaporation of the solvent under vacuum, the crude
product was purified by crystallization in ethanol to afford 3.50 g
4,4'-((1E,1'E)-(3,3'-bis(4-nitrophenyl)-[2,2'-bithiophene]-5,5'-
diyl)bis(ethene-2,1-diyl))bis(N,N-dibutylaniline) (3). Under an
inert atmosphere, 0.05 g (0.49 mmol) of an oven dried t-BuOK
was added to a solution of 0.23 g (0.47 mmol) of 4-(p-
nitrobenzyl)triphenylphosphonium bromide in 10 mL of
anhydrous CH2Cl2. After 10 min of stirring at 0 °C, 0.01 g (0.26
mmol) of 18-crown-6 and 0.07 g (0.10 mmol) of 4 were added.
The reaction mixture was stirred at room temperature for 24 h.
After removal of the solvent under reduced pressure the crude
product, thus obtained was purified over silica gel column using
CH2Cl2/C6H12 (1:1) to afford 0.03 g (28%) of the title compound
1
(68%) of title compound as yellow solid. Mp = 146-148 °C. H
NMR (250 MHz, CDCl3) δ: 3.98-4.00 (m, 4H, 2 x O-CH2-CH2-
O-); 4.10-4.14 (m, 4H, 2 x O-CH2-CH2-O-); 5.73 (s, 2H, 2 x -CH-
O-); 7.91 (s, 2H, 2 x Hthio); 9.91 (s, 2H, 2 x -CHO). 13C NMR
(67.5 MHz, CDCl3) δ: 65.5 (CH2); 98.0 (CH); 135.5 (Cthio); 139.4
(C); 140.4 (C); 144.5 (C); 181.6 (CHO); 182.7 (CHO). HRMS
(ESI+) m/z: 367 [M+H]+; 398 [M+Na]+; 405 [M+K]+. Elemental
analysis for C16H16O6S2 (%), calculated: C, 52.45; H, 3.85; O,
26.20; S, 17.50 - Found: C, 53.35; H, 4.09; O, 25.19; S, 17.22.
1
as a redish orange solid. Mp = 236-238 °C. H NMR (250 MHz,
3
CDCl3) δ: 0.94-1.00 (t, 12H, J = 7.3 Hz, x-CH2-CH2-CH2-CH3);
1.33-1.39 (m, 8H, x-CH2-CH2-CH2-CH3); 1.60-1.63 (m, 8H, x-
3
CH2-CH2-CH2-CH3); 3.28-3.34 (t, 8H, J = 7.1 Hz, x-CH2-CH2-
3
3
CH2-CH3); 6.63 (d, 4H, J = 8.7 Hz, 4xHbenz); 6.90 (d, 2H, J
4,4'-((1E,1'E)-(3,3'-di(1,3-dioxolan-2-yl)-[2,2'-bithiophene]-5,5'-
diyl)bis(ethene-2,1-diyl)bis(N,N-dibutylaniline) (5). Under an
inert atmosphere, 0.26 g (2.32 mmol) of dry t-BuOK was added
to a solution of 1.26 g (2.26 mmol) of 4-(N,N–dibutylbenzyl)-
triphenylphosphonium iodide in 10 mL of CH2Cl2. After 10 min
3
=15.6 Hz, 2 x Heth); 6.99 (d, 2H, J = 15.6 Hz, 2xHeth); 7.00 (d,
2H, J = 16.6 Hz, 2 x Heth); 7.23 (d, 4H, J = 16.6 Hz, 2xHeth);
7.32 (s, 2H, 2xHthio); 7.35 (d, 4H, J = 8.7 Hz, 4xHbenz); 7.45 (d,
4H, J = 8.6 Hz, 4xHbenz); 8.07 (d, 4H, J = 8.6 Hz, 4 x Hbenz).
3
3
3
3
3
5

6
Tetrahedron
HRMS (ESI+) m/z: 918.4207 M+· (calculated: 918.4207).
ACCEPTED MANUSCRIPT
Elemental analysis for C56H62N4S2O4(%): C, 73.17; H, 6.80; S,
6.98; N, 6.09 - Found: C, 71.30; H, 7.25; S, 6.17; N, 5.30.
2,2'-((5,5'-bis((E)-4-(dibutylamino)styryl)-[2,2'-bithiophene]-
2. Arias, A. C.; MacKenzie, J. D.; McCulloch, I.; Rivnay, J.; Salleo,
A. Chem. Rev. 2010, 110, 3-24.
3. Zhu, Z. H.; Peng, J.; Cao, Y.; Roncali, J. Chem. Soc. Rev. 2011,
40, 3509-3524.
4. Dong, H.; Wang, C.; Hu, W. Chem. Commun. 2010, 46, 5211-
5222.
3,3'-diyl)bis(methanylylidene))dimalonodinitrile (2). To
a
solution of 0.05 g (0.074 mmol) of compound 4 and 0.01 g
(0.154 mmol) of malonodinitrile in 4 mL of anhydrous CH2Cl2
were added 30 mol% of ethylenediammonium diacetate (EDDA).
The mixture was stirred at room temperature for 1 h. After
addition of water and extraction with CH2Cl2, the organic phase
was washed with NaHCO3 (1M) and brine before drying on anh.
MgSO4. After filtration the solvent was removed under reduce
pressure and the crude product was purified by crystallization in
diethyl ether to give 0.03 g (52%) of title compound as dark
green solid. Mp = 212-214 °C. H NMR (250 MHz, CDCl3) δ:
0.94-1.00 (t, 12H, J = 7.3 Hz, 4 x -CH2-CH2-CH2-CH3); 1.33-
1.42 (m, 8H, 4 x -CH2-CH2-CH2-CH3); 1.54-1.66 (m, 8H, 4 x -
CH2-CH2-CH2-CH3); 3.28-3.34 (t, 8H, J = 7.7 Hz, 4 x -CH2-
5. Wang, C.; Dong, H.; Hu, W.; Liu, Y.; Zhu, D. Chem. Rev. 2012,
112, 2208-2267.
6. a) Darling, S. B.; You, F. RSC Adv. 2013, 3, 17633-17648; b)
Malytskyi, V.; Simon, J. J.; Patrone, L.; Raimundo, J.-M. RSC
Adv. 2015, 5, 354-397.
7. Lin, Y.; Li, Y.; Zhan, X. Chem. Soc. Rev. 2012, 41, 4245-4272.
8. Servaites, J. D.; Ratner, M. A.; Marks, T. J. Energy Environ. Sci.
2011, 4, 4410-4422 and references cited therein.
9. Mas-Torrent, M.; Rovira, C. Chem. Rev. 2011, 111, 4833-4856.
10. Kanibolotsky, A. L.; Perepichka, I. F.; Skabara, P. J. Chem. Soc
Rev. 2010, 39, 2695-2728.
1
3
11. Organic Photovoltaics: Materials, Device Physics, and
Manufacturing Technologies (Eds.: C. Brabec, V. Dyakonov, U.
Scherf), Wiley-VCH, Weinheim, 2008.
3
3
12. Jiang, W.; Li, Y.; Wang, Z.Chem. Soc. Rev.2013, 42, 6113-6127.
13. Didane, Y.; Mehl, G. H.; Kumagai, A.; Yoshimoto, N.; Videlot-
Ackermann, C.; Brisset, H. J. Am. Chem. Soc. 2008, 130, 17681-
17683.
CH2-CH2-CH3); 6.63 (d, 4H, J = 8.7 Hz, 4 x Hbenz); 6.96 (s, 4H,
4 x Heth); 7.37 (d, 4H, J = 8.7 Hz, 4 x Hbenz); 7.50 (s, 2H, 2 x
H
Elemental analysis for C48H52N2S2 (%): C, 74.19; H, 6.74; S,
8.25; N, 10.81 - Found: C, 74.14; H, 6.86; S, 8.34; N, 10.63.
3
thio); 7.89 (s, 2H, 2 x Heth). HRMS (ESI+) m/z: 799.4 [M+Na]+.
14. (a) Videlot-Ackermann, C.; Brisset, H.; Ackermann, J.; Zhang, J.;
Raynal, P.; Fages, F.; Mehl, G.H.; Tnanisawa, T.; Yoshimoto, N.
Org. Electron. 2008, 9, 591–601; (b) Piron, F.; Leriche, P.;
Mabon, G.; Grosu, I.; Roncalli, J. Electrochem. Commun.2008,
10, 1427-1430.
15. Videlot-Ackermann, C.; Brisset, H.; Zhang, J.; Ackermann, J.;
Nénon, S.; Fages, F.; Marsal, P.; Tanisawa, T.; Yoshimoto, N. J.
Phys. Chem. C 2009, 113, 1567-1574.
16. Aboubakr, H.; Tamba, M.-G.; Diallo, A. K.; Videlot-Ackermann,
C.; Belec, L.; Siri, O.; Raimundo, J.-M.; Mehl, G. H.; Brisset, H.
J. Mater. Chem. 2012, 22, 23159-23168.
17. Aboubakr, H.; Raimundo, J.-M.; Brisset, H. Tetrahedron 2015,
71, 4079-4083.
5,5'-((5,5'-bis((E)-4-(dibutylamino)styryl)-[2,2'-bithiophene]-
3,3'-diyl)bis(methanylylidene))bis(1,3-diethyl-2-
thioxodihydropyrimidine-4,6(1H,5H)-dione) (1). To a solution of
0.05 g (0.073 mmol) of compound 4 and 0.03 g (0.154 mmol) of
1,3-diethylthiobarbituric acid in 4 mL of anhydrous CH2Cl2 were
added 30 mol% of ethylenediammonium diacetate (EDDA). The
mixture was stirred at room temperature for 30 min. After
addition of water and extraction with CH2Cl2, the organic phase
was washed with NaHCO3 (1M) followed by brine and dried
over anh. MgSO4. The solvent was removed under reduce
pressure and the crude product was purified by crystallization in
diethyl ether to give 0.04 g (53%) of title compound as a dark
18. Gallazzi, M. C.; Toscano, F.; Paganuzzi, D.; Bertarelli, C.; Farina,
A.; Zotti, G. Macromol. Chem. Phys. 2001, 202, 2074-2085.
19. Raimundo, J.-M.; Blanchard, P.; Gallego-Planas, N.; Mercier, N.;
Ledoux-Rak, I.; Hierle, R.; Roncali, J. J. Org. Chem. 2002, 67,
205-218.
1
20. For more informations, see website of Spectropôle from Aix-
green solid. Mp = 264-266 °C. H NMR (250 MHz, CDCl3) δ:
0.94-1.00 (t, 12H, J = 7.3 Hz, 4 x -CH2-CH2-CH2-CH3); 1.33-
1.42 (m, 8H, 4 x -CH2-CH2-CH2-CH3); 1.54-1.66 (m, 8H, 4 x -
CH2-CH2-CH2-CH3); 3.28-3.34 (t, 8H, J = 7.7 Hz, 4 x -CH2-
Marseille
3mrs.fr/presentation0.htm
University:
http://www.spectropole.u-
3
21. Gaussian 09, Revision D.01, Frisch, M. J.; Trucks, G. W.;
Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.;
Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. A.;
Nakatsuji, H.; Caricato, M.; Li, X.; Hratchian, H. P.; Izmaylov, A.
F.; Bloino, J.; Zheng, G.; Sonnenberg, J. L.; Hada, M.; Ehara, M.;
Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.;
Honda, Y.; Kitao, O.; Nakai, H.; Vreven, T.; Montgomery, J. A.,
Jr.; Peralta, J. E.; Ogliaro, F.; Bearpark, M.; Heyd, J. J.; Brothers,
E.; Kudin, K. N.; Staroverov, V. N.; Kobayashi, R.; Normand, J.;
Raghavachari, K.; Rendell, A.; Burant, J. C.; Iyengar, S. S.;
Tomasi, J.; Cossi, M.; Rega, N.; Millam, J. M.; Klene, M.; Knox,
J. E.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.;
Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.;
Cammi, R.; Pomelli, C.; Ochterski, J. W.; Martin, R. L.;
Morokuma, K.; Zakrzewski, V. G.; Voth, G. A.; Salvador, P.;
Dannenberg, J. J.; Dapprich, S.; Daniels, A. D.; Farkas, Ö.;
Foresman, J. B.; Ortiz, J. V.; Cioslowski, J.; Fox, D. J. Gaussian,
Inc., Wallingford CT, 2009.
3
3
CH2-CH2-CH3), 6.63 (d, 4H, J = 8.7 Hz, 4 x Hbenz); 6.96 (s, 4H,
3
4 x Heth); 7.37 (d, 4H, J = 8.7 Hz, 4 x Hbenz); 7.50 (s, 2H, 2 x
Hthio); 7.89 (s, 2H, 2 x Heth). HRMS (ESI+) m/z: 1044.5 M+·
(calculated: 1044.5). Elemental analysis for C58H72N6S4O4 (%):
C, 66.63; H, 6.94; S, 12.27; N, 8.04 - Found: C, 65.75; H, 8.46;
S, 6.83; N, 4.76.
Acknowledgement
This work was supported by the Centre National de la Recherche
Scientifique (CNRS) and the Ministère de l’Enseignement
Supérieur et de la Recherche. Financial support from ANR
program (SAGe III-V project ANR-11-BS10-012) and "Solutions
Communicantes Sécurisées" (SCS) competitive cluster are also
acknowledged. We also thank M. Giorgi (Spectropole, Marseille)
for the crystal structure determinations. H.A. also thanks the
Ministère de l’Enseignement Supérieur et de la Recherche for his
doctoral Financial support. MCIA (Mesocentre de Calcul Intensif
Aquitain) is gratefully acknowledged for calculation facilities.
22. a) Becke, A. D. Phys. Rev. A 1988, 38, 3098-3100; b) Becke, A.
D. J. Chem. Phys., 1993, 98, 5648-5652; c) Lee, C.; Yang, W.;
Parr, R. G. Phys. Rev. B 1988, 37, 785-789; d) Zhao, Y. and
Truhlar, D. G. Theor. Chem. Acc., 2008, 120, 215-241.
23. Hariharan, P. C.; Pople, J. A. Theor. Chim. Acta, 1973, 28, 213–
222.
References
1. (a) Murphy, A. R.; Fréchet, J. M. J. Chem. Rev. 2007, 107, 1066-
1096; (b) Yang, J.; Yan, D.; Jones, T. S. Chem. Rev. 2015, 115,
5570-5603; (c) Dou, L.; Liu, Y.; Hong, Z.; Li, G.; Yang, Y. Chem.
Rev. 2015, 115, 12633-12665.
6