Synthesis, crystal structure, and polymerization of butterfly-shaped thieno[3,2-b]thiophene oligomers

Article abstract of DOI:10.1039/c3nj40909k

A series of new butterfly-shaped thieno[3,2-b]thiophene oligomers with phenyl and thiophene units were synthesized through Suzuki coupling and Stille coupling reactions. The optical and thermal properties of these materials can be tuned by varying both su

Full text of DOI:10.1039/c3nj40909k

NJC
View Article Online
View Journal
PAPER
Synthesis, crystal structure, and polymerization of
butterfly-shaped thieno[3,2-b]thiophene oligomers†
Cite this: DOI: 10.1039/c3nj40909k
Ying Liu, Qida Liu, Xingye Zhang, Ling Ai, Yang Wang, Ruixiang Peng and Ziyi Ge*
A series of new butterfly-shaped thieno[3,2-b]thiophene oligomers with phenyl and thiophene units
were synthesized through Suzuki coupling and Stille coupling reactions. The optical and thermal
properties of these materials can be tuned by varying both substituents and the conjugation length.
The crystal structures have been determined and showed a syn- or anticlinal conformation in the crystal
of molecule 4. The electronic properties of the monomers and their electropolymerization ability are
discussed and rationalized as a function of their molecular structure. Moreover, stable cross-linked
conjugated polymers were formed by electropolymerization.
Received (in Montpellier, France)
10th October 2012,
Accepted 25th January 2013
DOI: 10.1039/c3nj40909k
www.rsc.org/njc
to Scheme 1 and their crystal structures, optical, and electro-
chemical properties were investigated.
Introduction
Thiophenes are one of the most important classes of heterocyclic
compounds, not only as key structural units of compounds with
interesting biological activities but also in the field of material
chemistry. Interest in thiophenes has been extended to fused
thiophenes, such as thieno[3,2-b]thiophenes. Indeed, these and
closely related materials with the incorporation of rigid thieno-
[3,2-b]thiophene units in conjugated oligomers or polymers have
been developed to improve their electronic properties and to
optimize the performance of the corresponding devices, for
example, organic field-effect transistors (OFETs),1–6 organic
light-emitting diodes (OLEDs),7,8 photovoltaics.9 In fact, the
performance of a functional material is strongly dependent on
its molecular organization and structure. The arrangement,
namely the packing motif, plays a very important role in the
performance of an organic electronic device. Therefore, design
of functional molecular solid-state structures, or arrangements,
through tuning of the intermolecular interactions is important.
In this paper, we present a facile route to precisely obtain a
novel type of ‘‘butterfly-shaped’’ molecular material, wherein
one thieno[3,2-b]thiophene acts as the planar backbone, and
phenyl or thiophene acts as the branches. Novel butterfly
thieno[3,2-b]thiophene derivatives functionalized with phenyl
or thienyl aromatic groups at the a- and b-positions were
synthesized by Suzuki and Stille coupling reactions according
Experimental
General procedures
Chemicals were purchased from Acros, Aldrich and used as
received. 2,3,5,6-Tetrabromothieno[3,2-b]thiophene was prepared
as outlined in the literature.11 Solvents and other normal reagents
were obtained from the Sinopharm Chemical Reagent Co., Ltd.
(SCRC). Solvents for reactions and photophysical measurements
(chloroform, THF, etc.) were all distilled after dehydration
according to conventional methods.
Instrumentation
1
The H NMR and 13C NMR spectra were recorded on a Bruker
DMX 400 NMR spectrometer. Chemical-shift data for each
signal were reported in ppm units with tetramethylsilane
(TMS) as internal reference, where d (TMS) = 0. MS spectra
were recorded on a Micromass GCT-MS spectrometer. Elemental
analyses were performed on a Carlo Erba model 1160 elemental
analyzer.
Syntheses
Preparation of 3
To a solution of 2 (1.38 g, 3 mmol) and phenylboronic acid (2.44 g,
20 mmol) dissolved in THF (300 mL) was added an aqueous 2 M
potassium carbonate solution (50 mL). The mixture was bubbled
with nitrogen for 30 min. Tetrakis-(triphenylphosphine)palladium
(0) (345 mg, 0.3 mmol) was then added. The mixture was heated to
80 1C for 48 hours under a nitrogen atmosphere. The reaction was
Ningbo Institute of Material Technology and Engineering, Chinese Academy of
Sciences, Ningbo 315201, China. E-mail: geziyi@nimte.ac.cn;
Fax: +86-574-86685043; Tel: +86-574-86690273
† CCDC 759956 for compound 3, 759959 for compound 4, and 759958 for
compound 5. For ESI and crystallographic data in CIF or other electronic format
see DOI: 10.1039/c3nj40909k
c
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2013
New J. Chem.

View Article Online
Paper
NJC
Scheme 1 Synthetic route of molecules 3–6.
cooled to room temperature and poured into water (500 mL) to (dd, J = 6.8 Hz, 2H) ppm; 13C NMR (CDCl3): d = 138.32, 135.27,
give a precipitate. After the obtained materials were purified by 135.12, 133.08, 128.15, 127.51, 127.36, 127.29, 126.41, 124.77;
multiple Soxhlet extraction using methanol and acetone, they anal. calcd for C22H12S6: C, 56.37; H, 2.58; S, 41.05%; found: C,
were purified by gradient sublimation. Further purification was 56.03; H, 2.62; S, 41.39%.
carried out by sublimation along a temperature gradient of
The black residue was purified by sublimation as colorless
250–180–100 1C at 10ꢀ2 Pa in a N2 atmosphere to obtain a solids to give 5. Further purification was carried out by sublima-
colorless crystal block of 3. The resulting colorless crystal block tion along a temperature gradient of 250–180–100 1C at 10ꢀ2 Pa
was suitable for X-ray analysis. 0.74 g, 56% yields. MALDI-TOF: in a N2 atmosphere to obtain a yellow crystal prism of 5. The
443.7; 1H NMR (400 MHz, CDCl3): d = 7.47 (m, 4H), 7.37 resulting yellow crystal prism was suitable for X-ray analysis.
(m, 4H), 7.34 (m, 8H), 7.27 (m, 4H) ppm; 13C NMR (CDCl3): 0.22 g (15%). MS: 461; 1H NMR (400 MHz, CDCl3): d = 7.48 (d, J =
d = 139.05, 139.01, 135.09, 134.61, 130.68, 129.35, 129.07, 3.6 Hz, 2H), 7.42 (d, J = 4.0 Hz, 2H), 7.13 (t, J = 8.0 Hz, 2H) ppm;
128.80, 128.53, 127.65; anal. calcd for C30H20S2: C, 81.04; H, anal. calcd for C14H6Br2S4: C, 36.38; H, 1.31; Br, 34.57; S, 27.75%;
4.53; S, 14.42%; found: C, 80.87; H, 4.56; S, 14.52%.
found: C, 36.07; H, 1.35; Br, 35.06; S, 27.58%.
Preparation of 4 and 5
Preparation of 6
Compounds 4 and 5 were prepared according to the procedure 2 (1.38 g, 3 mmol) and tributyl(5-hexylthiophen-2-yl)stannane
used for 3 and by the Suzuki coupling reaction between 2 (9.16 g, 20 mmol) were dissolved in toluene (300 mL). The mixture
(1.38 g, 3.0 mmol) and a-thiopheneboronic acid (1.92 g, was bubbled with nitrogen for 30 min. Bis(triphenylphosphine)-
15 mmol). The obtained materials were purified by multiple palladium(II)chloride (226 mg, 0.3 mmol) was then added. The
Soxhlet extraction using methanol, acetone and chloroform. mixture was heated to 120 1C for 48 hours under a nitrogen
The chloroform solvent was removed to give a yellow solid. atmosphere. The reaction was cooled to room temperature and
Further purification was carried out by sublimation along a the toluene was removed. The obtained solids were purified by
temperature gradient of 250–180–100 1C at 10ꢀ2 Pa in a N2 multiple Soxhlet extraction using methanol and ethanol. The
atmosphere to obtain a yellow crystal block of 4. The resulting solvent of ethanol was removed to give yellow solid. Recrystallization
yellow crystal block was suitable for X-ray analysis. 0.7 g, (50%). from ethanol gave yellow solids. 1.8 g (75%), mp: 75 1C. MALDI-TOF:
MALDI-TOF: 468.0; 1H NMR (400 MHz, acetone-d6): d = 7.64 804.2; 1H NMR (400 MHz, acetone-d6): d = 7.14 (d, J = 3.6 Hz, 2H),
(dd, J = 6.8 Hz, 2H), 7.60 (dd, J = 6.8 Hz, 2H), 7.32 (dd, J = 4.8 Hz, 7.10 (d, J = 3.6 Hz, 2H), 6.89 (d, J = 3.6 Hz, 2H), 6.84 (d, J = 3.2 Hz,
2H), 7.29 (dd, J = 4.8 Hz, 2H), 7.20 (dd, J = 6.8 Hz, 2H), 7.14 2H), 2.82–2.89 (m, 8H), 1.64–1.74 (m, 8H), 1.39–1.44 (m, 24H),
c
New J. Chem.
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2013

View Article Online
NJC
Paper
1.33–1.36 (m, 12H) ppm; anal. calcd for C46H60S6: C, 68.60; H, values of compounds 3 and 4 were 319 1C and 346 1C respec-
7.51; S, 23.89; found: C, 68.42; H, 7.59; S, 24.15%.
tively. Compound 5 demonstrated the lowest stability (Td =
275 1C) due to the presence of two bromo-moieties. In contrast,
compound 6 bearing four 2-hexylthiophene units between the
X-ray crystallography
Crystallographic data for 3: chemical formula: C30H20S2; for- thieno[3,2-b]thiophene, exhibited the decomposition tempera-
mula weight (M): 444.58; temperature: 293(2) K; monoclinic; ture as high as 406 1C. The heating and cooling DSC scans of
P21/c; a = 6.1134(12), b = 12.529(3), c = 14.622(3) Å, a = 90.001, the compound 3 show no glass transitions from room tempera-
b = 92.51(3)1, g = 90.001; V = 1118.9(4) Å3; Z = 2; rcalcd = 1.320 g ture up to 275 1C, due to dense molecular packing.15,16 DSC
cmꢀ3; number of reflections collected: 11 099; final R = 0.0444, analysis revealed that compounds 4 and 5 exhibit reversible
wR = 0.1151. Crystallographic data for 4: chemical formula: thermal transitions at 250 1C and 235 1C, respectively. Com-
C
22H12S6; formula weight (M): 468.68; temperature: 113(2); pound 6 containing four hexyl chains exhibited a lower melting
monoclinic; P21/n;
a
=
6.1799(12),
b
=
7.6986(15),
c
=
point at 75 1C than compounds 4 and 5.
21.307(4) Å, a = 90.001, b = 97.69(3)1, g = 90.001; V =
Because of their virtual insolubility in organic solvents,
1004.6(3) Å3; Z = 2; rcalcd = 1.549 g cmꢀ3; number of reflections compounds 3, 4 and 5 were purified by gradient sublimation
collected: 6086; final R = 0.1182, wR = 0.3378. Crystallographic along a temperature gradient of 250–180–100 1C at 10ꢀ2 Pa in a
data for 5: chemical formula: C14H6Br2S4; formula weight (M): N2 atmosphere. X-ray crystal structure measurements were car-
462.25; temperature: 113(2); monoclinic; P21/c; a = 3.9007(11), ried out in the reflection mode using a Rigaku MM-007 X-ray
b = 11.814(3), c = 15.453(3) Å, a = 90.001, b = 94.644(14)1, g = diffraction system (Mo-Ka radiation, l = 0.71073 Å). The result-
90.001; V = 709.8(3) Å3; Z = 2; rcalcd = 2.163 g cmꢀ3; number of ing colorless crystal block of 3, the yellow crystal block of 4 and
reflections collected: 1223; final R = 0.0971, wR = 0.2700. From the yellow crystal prism of 5 were suitable for X-ray analysis.
the crystallographic data of compound 5, it is found that there
As shown in Fig. 1, all molecules display an inner flat,
is a large and unexplained residual electron density of 2.65 in symmetric molecular geometry, while the peripheral phenyl
this structure, located at (0.0656, 0.7156, 0.0961) and at a or thienyl units adopt twisted forms, connecting with the
distance of 1.29 Å from the Br atoms.
thieno[3,2-b]thiophene like a flying butterfly. The three mole-
cular structures lie about an inversion center at the mid-point
of the central C–C bond of the thieno[3,2-b]thiophene. The
dihedral angles of 35.81 and 59.41 are observed between the
Results and discussion
Thieno[3,2-b]thiophene (1)10 was chosen as the parent compound thieno[3,2-b]thiophene and phenyl rings in molecule 3, and
and was easily converted to 2,3,5,6-tetrabromothieno[3,2-b]thio- 22.01 and 77.81 between the thieno[3,2-b]thiophene and thienyl
phene (2) in high yield with bromine (Br2)–CHCl3.11 The target rings in molecule 4, and 7.61 between the thieno[3,2-b]thio-
compound 3 was then assembled via palladium-catalyzed Suzuki phene and thienyl rings in molecule 5. The molecular sheets for
coupling reactions of 2 with phenylboronic acid under reflux for compound 3 piled up in the a-axis direction, and formed a
24 h in the aqueous K2CO3 and tetrahydrofuran (THF) in 56% yield. columnar stacking with an interplanar separation of 3.85 Å
This is a new method to synthesize compound 3, which avoids the (Fig. 1a). Between the stacks, the interaction is reinforced by
photochemical reaction conditions and bothersome purification close intermolecular C–Hꢁ ꢁ ꢁp contacts, which are significantly
steps that previous methods suffered from.12,13 The target com- different from intermolecular Sꢁ ꢁ ꢁS contacts found in most
pounds 4 and 5 were obtained via Suzuki coupling reactions of 2 other fused thiophenes.17–19 From Fig. 1b, a peculiar structural
with a-thiopheneboronic acid in different ratios. Compound 6 was feature of the compound 4 was prepared with disordered S
synthesized via an excess of tributyl(5-hexylthiophen-2-yl)stan- atoms. Interestingly, the four thiophene rings at the a- and b-
nane14 with compound 2 to ensure completion of the Stille- positions of the central unit can freely form a syn- or anticlinal
coupling reaction in 75% yield. The solubility of compound 6 is conformation. The population ratio is about 68 : 32 for the ring
the best in this series of target compounds, while compounds 4 connected to C2 and 89 : 11 for the ring connected to C3 from
and 5 are slightly soluble in common organic solvents (such as the crystal data. A similar situation has been observed for the
CHCl3 and THF). The target compounds were characterized by tetrathienylthiophene system.20 One of the conformations in
NMR spectroscopy, mass spectrometry (MS), and elemental the molecule 4 was S atoms in four thienyl arms facing each
analysis.
The thermal properties of the new thieno[3,2-b]thiophene
other (Fig. 1e) and the other in the opposite direction (Fig. 1d).
1
As shown in Fig. 2, H NMR spectra reveal the two sets of
oligomers have been evaluated by thermal gravimetric analysis protons with a splitting characteristic for the thiophene unit
(TGA) and differential scanning calorimetry (DSC) under an because the protons of the two thiophenes at a- (2,5 position of
argon atmosphere. TGA measurements were carried out on a thieno[3,2-b]thiophene core) and b-positions (3,6 position of
TA SDT 2960 instrument under a dry nitrogen flow, heating thieno[3,2-b]thiophene core) are not equivalent (labelled a–c
from room temperature to 550 1C, at a heating rate of 10 1C and a0–c0), because the protons of the thienyl arms at the a-
minꢀ1. DSC analyses were performed on a TA DSC 2010 positions are more involved in conjugation with the central
instrument under a dry N2 flow at a heating rate of 10 1C core than those at the b-position. This is confirmed by the
minꢀ1. All compounds showed significant thermal stability difference in the corresponding dihedral angles between the
(Td), with 2% weight loss, values higher than 275 1C. The Td plane of the core and that of the arms.
c
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2013
New J. Chem.

View Article Online
Paper
NJC
Fig. 1 Crystal structures of 3 (a), 4 (b, d, e), and 5 (c) with 40% probability ellipsoids. [Hydrogen atoms were omitted for clarity in (a) and (b). Symmetry operators
indicated by ‘‘A’’ in the atom labels: (ꢀx, 1 ꢀ y, 1 ꢀ z) for compound 3; (1 ꢀ x, 2 ꢀ y, ꢀz) for compound 4; (1 ꢀ x, 1 ꢀ y, ꢀz) for compound 5.]
Fig. 2 1H NMR spectrum of 4 at room temperature in acetone-d6 (labelled a–c
and a0–c0).
Fig. 3 Normalized absorption spectra of compounds 3–6 in tetrahydrofuran
The optical absorption spectra of compounds 3–6 in THF
solutions are shown in Fig. 3. Compounds 3, 4, 5, and 6 exhibit
solution.
maximum absorption at 339, 361, 367, and 374 nm, respec-
tively, but a shoulder peak appears in the spectra at 275 nm for
compound 4 and at 290 nm for compound 6. Compounds 4 and thiophene substituted compound 4. In contrast to their absorp-
6 all have oligothiophene branches (thiophene or 2-hexylthio- tion spectra, only one emission peak was observed in the
phene). The connection between each thiophene unit includes emission spectra of these compounds. The emission peaks shift
a- and b-position linkages with the thieno[3,2-b]thiophene core. from 420 to 593 nm upon gradually changing the conjugated
The a-linkage thiophene segment provides the best p-electron branches. These results demonstrate that the compounds can be
conjugation, and b-linkages between the branches may lead to electronically fine-tuned by manipulating the branch segments.
the shoulder peaks, which is in agreement with previously The optical bandgap of the compounds can be deduced from the
reported related research on substituted thiophene architec- longest-wavelength absorption edge. The band gaps of 4, 5, and
tures. The absorption spectra of 2-hexylthiophene substituted 6 with thiophene units (2.92, 2.98, and 2.82 eV, respectively) are
compound 6 exhibit a small redshift similar to that of narrow compared to that of phenyl units 3 (3.23 eV).
c
New J. Chem.
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2013

View Article Online
NJC
The electronic properties of these compounds were investigated
Paper
by cyclic voltammetry (CV). CV measurements were carried out on
a computer-controlled CHI660C instrument at RT using vacuum-
deposited thin film (thickness of the oligomer: 10 nm) onto
indium tin oxide (ITO)-coated glass as a working electrode in order
to estimate the oxidative stability of thin films of the oligomers. A
platinum rod was used as a counter electrode, Ag/AgCl as a
reference electrode, dichloromethane (dried by distillation over
CaH2) as a solvent and 0.1 M tetrabutylammonium hexafluorophos-
phate as a supporting electrolyte, the scan rate being 100 mV sꢀ1
.
The CV plots displaying oxidation processes and reduction poten-
tials below zero voltage could not be observed, which are shown in
Fig. 4. We could see that the highest occupied molecular orbital
(HOMO) levels of the four compounds show a slight increase as
the number of thiophene rings increases. The HOMO level is
raised in energy by ꢀ5.61, ꢀ5.37, ꢀ5.55 and ꢀ5.28 eV, whereas the
LUMO level is estimated to be ꢀ2.38, ꢀ2.45, ꢀ2.57 and ꢀ2.46 eV
in 3, 4, 5, and 6, respectively.
For all four monomers, multiple potential scans on the ITO
electrode were carried out. No polymerization was observed for
phenyl end-caped compound 3 and the a-position-blocked
compound 6. This result is not surprising because it is well-
known that polymerization takes place easily at the a-position
of thiophenes.21–24 As shown in Fig. 4, compounds 4 and 5 are
more susceptible to being deposited as polymer films on the
electrodes by potential cycling. The electrochemical studies of
the films of poly(4) (the polymers of 4) and poly(5) (the poly-
mers of 5) both showed switching from yellow, brown to purple
in color. The gradual increase in the current response and the
new broad peak observed at lower potentials are typical char-
acteristics of conducting-polymer formation on the electrode
surfaces.25–31 The onset oxidation potentials of poly(4) and
poly(5) are higher than those of the monomers 4 and 5. More-
over, the electrochemical processes of the films are very stable,
with no obvious changes in the cyclic voltammetry during
subsequent repeat scanning.
Fig. 5 UV–vis absorption spectra of poly(5) films deposited on ITO.
polymerization conditions. Fig. 5 shows the absorption spectra
of the poly(5) films deposited by cyclic voltammetry over 2, 5,
and 10 cycles. In this way, the photophysical properties of the
polymers could be investigated under different polymerization
conditions. The red-shift of the absorption and band broad-
ening indicate that the polymers have an extended conjugation
system compared to the monomers. The absorption maxima of
the polymers are all quite close to that of polyalkylthiophenes
(434 nm).32 The results suggest the formation of the dendritic
hyperbranched polythiophenes. Because of the ease of synth-
esis of the monomer, larger quantities of polymers are likely to
be achieved by chemical polymerization with iron(III) chloride
and this is currently under investigation.
Conclusions
A series of new conjugated oligomers based on the thieno[3,2-b]-
thiophene core with phenyl and thiophene units were successfully
synthesized by a facile synthetic route and could be described as
having a butterfly-like shape. The synthetic route would also be
applicable to the preparation of various functional materials by
modifying thieno[3,2-b]thiophene. It was demonstrated that the
optical and thermal properties of these materials can be fine-tuned
by varying both substituents and the conjugation length. Moreover,
the molecular structures have an inversion center at the mid-point
of the central C–C bond of the thieno[3,2-b]thiophene. The crystals
of 4 freely formed a syn- or anticlinal conformation. The thiophene
functionalized monomers are susceptible to being deposited by
electropolymerization, which results in the formation of electro-
active polymers.
For optical studies, monomer 5 was electropolymerized on
an indium tin oxide (ITO) transparent electrode under different
References
1 Y. Liu, C.-a. Di, C. Du, Y. Q. Liu, K. Lu, W. Qiu and G. Yu,
Chem.–Eur. J., 2010, 16, 2231.
2 H.-S. Kim, Y.-H. Kim, T.-H. Kim, Y.-Y. No, S. Pyo, M. H. Yi,
D. Y. Kim and S.-K. Kwon, Chem. Mater., 2007, 19, 3561.
3 P. Liu, Y. Wu, H. L. Pan, Y. N. Li, S. Gardner, B. S. Ong and
S. P. Zhu, Chem. Mater., 2009, 21, 2727.
4 Y.-Y. Noh, R. Azumi, M. Goto, B.-J. Jung, E. Lim, H.-K. Shim,
Y. Yoshida, K. Yase and D.-Y. Kim, Chem. Mater., 2005,
17, 3861.
Fig. 4 Cyclic voltammograms of compounds 3–6 in CH2Cl2 (a). Electropolymer-
ization of 4 (b) and 5 (c), repeat potential scanning 10 cycles.
c
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2013
New J. Chem.

View Article Online
Paper
NJC
5 E. Lim, B.-J. Jung, J. Lee, H.-K. Shim, J.-I. Lee, Y. S. Yang and 18 Y. Mazaki and K. Kobayashi, J. Chem. Soc., Perkin Trans. 2,
L.-M. Do, Macromolecules, 2005, 38, 4531. 1992, 761.
6 I. Mcculloch, M. Heeney, C. Bailey, K. Genevicius, 19 Y. Liu, Y. Wang, W. Wu, Y. Liu, H. Xi, L. Wang, W. Qiu,
I. Macdonald, M. Shkunov, D. Sparrowe, S. Tierney, K. Lu, C. Du and G. Yu, Adv. Funct. Mater., 2009, 19, 772.
R. Wagner, W. Zhang, M. L. Chabinyc, R. J. Kline, 20 T. Benincori, V. Bonometti, F. De Angelis, L. Falciola,
M. D. Mcgehee and M. F. Toney, Nat. Mater., 2006, 5, 328.
7 J. H. Seo, E. B. Namdas, A. Gutacker, A. J. Heeger and
G. C. Bazan, Adv. Funct. Mater., 2011, 21, 3667.
M. Muccini, P. R. Mussini, T. Pilati, G. Rampinini,
S. Rizzo, S. Toffanin and F. Sannicol, Chem.–Eur. J., 2010,
16, 9086.
`
8 W. Tang, L. Ke, L. Tan, T. Lin, T. Kietzke and Z.-K. Chen, 21 P. Leriche, F. Piron, E. Ripaud, P. Frere, M. Allain and
Macromolecules, 2007, 40, 6164. J. Roncali, Tetrahedron Lett., 2009, 50, 5673.
9 H. Bronstein, Z. Chen, R. S. Ashraf, W. Zhang, J. Du, 22 T. Taerum, O. Lukoyanova, R. G. Wylie and
J. R. Durrant, P. S. Tuladhar, K. Song, S. E. Watkins, D. F. Perepichka, Org. Lett., 2009, 11, 3230.
Y. Geerts, M. M. Wienk, R. A. J. Janssen, T. Anthopoulos, 23 B. C. Thompson, K. A. Abboud, J. R. Reynolds, K. Nakatani
H. Sirringhaus, M. Heeneynad and I. McCulloch, J. Am.
Chem. Soc., 2011, 133, 3272.
10 S.-H. Jung, H. K. Kim, S.-H. Kim, Y. H. Kim, S. C. Jeoung and
D. Kim, Macromolecules, 2000, 33, 9277.
and P. Audebert, New J. Chem., 2005, 29, 1128.
24 X. Sun, Y. Q. Liu, S. Chen, W. Qiu, G. Yu, Y. Ma, T. Qi,
H. Zhang, X. Xu and D. Zhu, Adv. Funct. Mater., 2006,
16, 917.
11 L. S. Fuller, B. Iddon and K. A. Smith, J. Chem. Soc., Perkin 25 G. E. Collis and A. K. Burrell, J. Org. Chem., 2003, 68, 8974.
Trans. 1, 1997, 3465.
26 P. Audebert, J. M. Catel, G. Le Coustumer, V. Ducheneta and
12 N. Matsumura, H. Tanaka, Y. Yagyu, K. Mizuno, H. Inoue,
P. Hapiot, J. Phys. Chem. B, 1998, 102, 8661.
K. Takada, M. Yasui and F. Iwasaki, J. Org. Chem., 1998, 27 E. A. Dragu, S. Nica, M. Raicopol, A. Baran, D.-F. Anghel,
63, 163.
B. Cojocaru, L. Tarko and A. C. Razus, Tetrahedron Lett.,
13 S. Singh, M. M. Bhadbhade, K. Venkatesan and
V. Ramamurthy, J. Org. Chem., 1982, 47, 3550.
14 J. L. Brusso, O. D. Hirst, A. Dadvand, S. Ganesan, F. Cicoira,
2012, 53, 2611.
28 J. L. Reddinger and J. R. Reynolds, Chem. Mater., 1998,
10, 1236.
C. M. Robertson, R. T. Oakley, F. Rosei and D. F. Perepichka, 29 S. Y. Jang, G. A. Sotzing and M. Marquez, Macromolecules,
Chem. Mater., 2008, 20, 2484. 2002, 35, 7293.
15 T. Qi, Y. Q. Liu, W. Qiu, H. Zhang, X. Gao, Y. Liu, K. Lu, 30 C. O. Too, G. G. Wallace, A. K. Burrell, G. E. Collis,
C. Du, G. Yu and D. Zhu, J. Mater. Chem., 2008, 18, 1131.
16 S. Yao and K. D. Belfield, J. Org. Chem., 2005, 70, 5126.
D. L. Officer, E. W. Boge, S. G. Brodie and E. J. Evans, Synth.
Met., 2001, 123, 53.
17 X.-C. Li, H. Sirringhaus, F. Garnier, A. B. Holmes, 31 S. Scheib and P. Bauerle, J. Mater. Chem., 1999, 9, 2139.
S. C. Moratti, N. Feeder, W. Clegg, S. J. Teat and 32 J. Pei, J. L. Wang, X. Y. Cao, X. H. Zhou and W. B. Zhang,
R. H. Friend, J. Am. Chem. Soc., 1998, 120, 2206.
J. Am. Chem. Soc., 2003, 125, 9944.
c
New J. Chem.
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2013