Swivel-cruciform oligothiophene dimers

Article abstract of DOI:10.1039/b605338f

Synthesis and electronic properties of three swivel-cruciform oligothiophene dimers - bis(terthiophene) (BT3), bis(pentathiophene) (BT5) and bis(heptathiophene) (BT7) - with increased solubility in organic solvents are reported. We obtained a field-effect mobility of 3.7 × 10^-5 cm² V^-1 s^-1 and a current on/off ratio of >10³ for a solution-processed OFET device with dimer BT5 as p-type semiconductor. The Royal Society of Chemistry 2006.

Full text of DOI:10.1039/b605338f

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PAPER
www.rsc.org/materials | Journal of Materials Chemistry
Swivel-cruciform oligothiophene dimers{
a
Askin Bilge, Achmad Zen, Michael Forster, Hongbo Li, Frank Galbrecht, Benjamin S. Nehls,
Tony Farrell,{ Dieter Neher and Ullrich Scherf*
b
a
a
a
a
a
b
a
Received 13th April 2006, Accepted 22nd June 2006
First published as an Advance Article on the web 6th July 2006
DOI: 10.1039/b605338f
Synthesis and electronic properties of three swivel-cruciform oligothiophene dimers—
bis(terthiophene) (BT3), bis(pentathiophene) (BT5) and bis(heptathiophene) (BT7)—with
increased solubility in organic solvents are reported. We obtained a field-effect mobility of
2
5
2
21 21
3
3
.7 6 10 cm V
with dimer BT5 as p-type semiconductor.
s
and a current on/off ratio of .10 for a solution-processed OFET device
Introduction
by the attachment of terminal alkyl substituents as shown in a
1
previously published report.
6
Oligo- and polythiophenes have received increasing attention
because of numerous applications in areas such as energy
1
–7
Results and discussion
storage and electrochromic devices.
One of the important
areas where thiophene-based p-conjugated oligomers and
Synthesis
polymers have been widely applied is as semiconductors in
8
–11
Our synthetic strategy towards swivel-cruciform oligothio-
organic field-effect transistors (OFETs).
Hereby, solution-
phenes starts from 2,29,5,59-tetrabromo-3,39-bithienyl as the
processed organic semiconductors are the most promising
candidates for organic electronic devices on large area, flexible
substrates. The morphology of such solution-processed oligo-
or polythiophene thin layers is very important for the resulting
OFET performance.
1
7
central building block. We utilised the well known cross-
coupling reaction according to Stille to synthesize the dimers
1
BT3, BT5 and BT7 by cross coupling with the corresponding
8
stannylated (oligo)thiophenes as shown in Scheme 1.
Non-substituted oligothiophenes are characterized by
decreasing solubility with increasing number of thiophene
moieties. Higher homologues (e.g. pentathiophene (T5), or
sexithiophene (T6)) exhibit very low solubility in common
Optical and photoluminescent properties
As expected, the UV-Vis spectra (Fig. 1) of the swivel-
cruciform oligothiophene dimers BT3, BT5 and BT7 exhibit a
clear red-shift of the absorption maximum with increasing
length of the oligothiophene in both solution and solid states
(Table 1). The size of our most extended oligomer BT7 is still
significantly below the effective conjugation length of oligo-
thiophenes. B a¨ uerle et al. calculated the effective conjugation
length of oligothiophenes by plotting the inverse chain length
(1/n) versus the absorption energy. An extrapolation of the
graph indicates no convergence of the optical properties until
1
2
organic solvents. One strategy to increase solubility involves
the introduction of alkyl substituents either in the terminal
3
1
a- and v-positions of oligomers
or in 3-positions of
individual thienylene units of oligomers or polymers.
In this article, we would like to present an alternative
approach to soluble oligothiophenes without the attachment of
solubilizing alkyl side chains. In a previous paper we already
reported the synthesis and properties of a new family of oligo-
1
4
19–21
phenyl based swivel-cruciforms. The term swivel-cruciform
reflects the fact that the single bond connection of the two non-
substituted oligothiophenes at the central thienylene moieties
n y 16.
The absorption maxima of the oligothiophene dimers in
solution range from 361 nm (BT3) and 426 nm (BT5) to 451 nm
(BT7). These values are similar to the optical properties of the
1
5
permits, in contrast to the corresponding spiro-type dimers,
a
2
2
certain degree of rotation of the arms in the novel swivel-
cruciform which leads to increased solubility.
corresponding unsubstituted linear oligothiophenes T3–T6.
There is only a minor redshift of lmax of ca. 8 nm in BT3
compared to T3 and BT5 compared to T5, which is probably
due to a weak intramolecular electronic interaction of the arms
in BT3 and BT5. The comparison of the solid state and
solution spectra (Fig. 1) shows a distinct redshift of the film
spectra which is more pronounced for the more extended
dimers BT5 and BT7. The redshift is 7 nm for BT3, 20 nm
for BT5 and 58 nm for BT7. As in poly(3-hexylthiophene)s
(P3HT) this shift is explained by a transition into a
The solubility of the cruciform oligothiophene dimers and
the suitability for solution processing can be further improved
a
Bergische Universit a¨ t Wuppertal, Makromolekulare Chemie, Gaußstr.
20, D-42097, Wuppertal, Germany. E-mail: scherf@uni-wuppertal.de;
Fax: 49 202 439 3880; Tel: 49 202 439 3871
Universit a¨ t Potsdam, Institut f u¨ r Physik, Physik weicher Materie, Am
b
Neuen Palais 10, D-14415, Potsdam, Germany.
E-mail: neher@rz.uni-potsdam.de; Fax: 49 331 977 1083;
Tel: 49 331 977 1751
2
3
intramolecularly higher ordered solid state structure. In
accordance with this explanation the appearance of a distinct
vibronic structure is observed, especially for BT7 as also
{
Electronic supplementary information (ESI) available: TGA data
and AFM images. See DOI: 10.1039/b605338f
Present address: General Electric Plastics Europe BV, Plasticslaan 1,
{
2
4
PO Box 117, Bergen op Zoom 4600 AC, The Netherlands.
observed by other authors.
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3 4 3 4
Scheme 1 Synthesis of the swivel-cruciform oligothiophenes via Stille-type coupling reactions. (i) Pd[PPh ] , toluene, reflux, 24 h; (ii) Pd[PPh ] ,
toluene, reflux, 48 h.
Fig. 2 Photoluminescence spectra of BT3, BT5 and BT7 in chloro-
form solution and as spin-coated films at 298 (excitation
wavelength: BT3 365 nm (sol.), 370 nm (film); BT5 430 nm (sol.),
50 nm (film); BT7 455 nm (sol.), 490 nm (film)).
Fig. 1 UV-Vis absorption spectra of BT3, BT5 and BT7 in chloro-
K
form solution and as spin-coated films at 298 K.
4
Table 1 Wavelength and energy of the absorption maxima for swivel-
cruciform oligomers BT3, BT5 and BT7
Table 2 Wavelength and energy of the PL maxima for swivel-
cruciform oligomers BT3, BT5, and BT7
a
a
b
b
Sample
l
max /nm
E
abs /eV
l
max /nm
Eabs /eV
a
a
b
b
Sample
l
max /nm
E
em /eV
l
max /nm
Eem /eV
BT3
BT5
BT7
a
361
426
451
3.44
2.92
2.75
b
368
446
487; 509
3.37
2.78
2.55; 2.44
BT3
BT5
BT7
a
479
547
543; 567
2.59
2.27
2.28; 2.19
b
480; 500
598
605
2.58; 2.48
2.07
2.05
In chloroform at 298 K. Spin-coated films from a chloroform
solution at 298 K.
In chloroform at 298 K. Spin-coated films from a chloroform
solution at 298 K.
The PL emission maxima in solution (see Fig. 2 and
Table 2) also show a bathochromic shift with increasing
number of thiophene units. However, the PL spectra of
BT5 and BT7 are very similar, due to essentially faster
Thermal properties
The thermal properties are also strongly dependent on the
2
5
convergence of the emission properties. The solid state PL
spectra reflect similar trends as described for the absorption
properties.
number of thiophene units (Table 3). Oligothiophene BT3
shows both a glass transition temperature T
g
at 44 uC and a
m
melting point T at 207 uC during heating. In contrast, BT5
3
178 | J. Mater. Chem., 2006, 16, 3177–3182
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Table 3 DSC results of the swivel-cruciform oligothiophenes BT3,
BT5 and BT7
Sample
T
g
/uC
m
T /uC
BT3
BT5
BT7
a
44
107
146
207
—
—
a
a
Melting point not observed up to 300 uC.
and BT7 display only a glass transition temperature at 107 uC
for BT5 and 146 uC for BT7. Melting points of BT5 and BT7
have not been observed and may be located above the
decomposition temperature. The increase of the glass transi-
tion temperature indicates a higher morphological stability of
the higher oligomers in the amorphous solid state.
Fig. 3 Transfer characteristics of OFETs (taken at a drain-source
voltage VDS 280 V) made from BT5 ($) and BT7 (m) as the
semiconducting layers.
OFET experiments
As a next step, we investigated organic field-effect transistors
(
OFETs) based on BT3, BT5 and BT7. OFETs were fabricated
using a bottom gate geometry on highly doped n-type silicon
wafers which act as the gate electrode. A thermally grown
3
1
00 nm thick silicon dioxide layer with a capacitance of
2
1 nF cm served as the gate insulator. Prior to the deposition
2
of the semiconducting materials, the surface of the substrates
was carefully cleaned with the following detergents and
solvents: Helmanex (5% in water), milli-Q water, acetone and
isopropanol. Each cleaning step was performed for 15 minutes
in an ultrasonic bath. It is worth mentioning that additional
oxygen plasma treatment and silanisation with hexamethyl-
disilazane (HMDS) of the silicon dioxide layer prior to the
deposition of the oligothiophene dimers were not necessary.
BT3, BT5 and BT7 film layers were deposited by spin-coating
from hot chlorobenzene solution. The solubility was good
for BT3 and BT5 but fairly poor for BT7. Finally, 100 nm
thick interdigitating Au electrode structures were evaporated
on top of the thin organic semiconductor layer serving as
source and drain electrodes (channel length 100 mm, total
channel width 148.5 mm). The output and transfer charac-
teristics of the OFET devices were measured using an Agilent
1=2
Fig. 4 Square root plot of I
DS;sat
versus VGS (taken at VDS = 280 V)
of OFETs made from BT5 ($) and BT7 (m) as the semiconducting
layers.
from the slope of the linear fit of the data (Fig. 4) according
to eqn (1).
WCi
2
IDS,sat~
msatðVGS{VoÞ
(1)
2L
Here, W and L are the channel width and length, respectively,
and C is the capacitance per unit area of the SiO insulator.
i
2
4
155C semiconductor parameter analyzer from Hewlett
The output characteristics from OFETs based on as-
prepared BT5 and BT7 layers are shown in Figs. 5 and 6,
respectively. The OFETs exhibited negative amplification,
which is typical of p-type semiconductors with well-defined
linear and saturation regions. Although the film quality for
BT3 was very good, we could not observe any reasonable
transistor behavior for the shortest dimer. For OFETs made
from BT5, we obtained a field-effect mobility (mFET) of 3.7 6
Packard. All preparation processes and the characterization
of the devices were performed inside an N
glove box.
2
-atmosphere
Note that the drain currents of the transistors from BT5 are
distinctly higher than those of transistors made from BT7,
indicating better transport properties. This is also reflected
by the mobilities, which were calculated from the transfer
characteristics (see Figs. 3 and 4) using the square-root
25
2
21 21
3
1
0
cm V
s
and a current on/off ratio of 2.5 6 10 at
VDS = 280 V. The device made from BT7 showed a reduced
2
6
approach. Moreover, the on/off ratio is also larger for
BT5. The lower OFET performance of BT7 might be due to
the poor solubility resulting in a lower quality of the organic
films. Fig. 4 shows square root plots of the drain current at
saturation measured at VDS = 280 V as a function of the gate
voltage. The curves are fitted linearly and the intercept with
the VGS axis is used to determine the turn-on voltage of the
transistor (V ). The turn-on voltages V of both OFET devices
27
2
21 21
charge carrier mobility (mFET) of 8.8 6 10 cm V
s
with
2
an on/off ratio of 1.1 6 10 . We presume that the poor
solubility of BT7, leading to low quality, inhomogeneous films,
might be responsible for the poor performance.
Conclusions
o
o
are quite similar at ca. 220 V. The field-effect mobility of the
OFET devices in the saturation region (msat) was calculated
A series of novel swivel-cruciform oligothiophene dimers
have been synthesized via fourfold cross coupling of
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The Differential Scanning Calorimetry analyses were accom-
plished on a Mettler DSC 30. TGA data of BT3, BT5 and BT7
and AFM images of BT5 films are provided as ESI.{ The TG
analyses were measured on a Mettler TG 50.
Materials and general procedures
Unless otherwise indicated, all reagents were obtained from
commercial suppliers and were used without further purifica-
tion. All reactions were carried out under an argon atmosphere
by use of standard and Schlenk techniques. The solvents were
used as commercial p.a. quality.
Synthesis of materials
Fig. 5 Output characteristic of an OFET device prepared from BT5
3,39-Dithienyl (1). To a solution of 3-bromothiophene (10 g,
2 mmol) in 50 ml of diethyl ether, a 2.5 M solution of n-BuLi
as the semiconducting layer.
6
in hexane (24.8 ml, 62 mmol) was added dropwise at 270 uC
within 30 minutes. The mixture was stirred for 15 minutes,
then allowed to warm up to 255 uC. CuCl2 was added in
portions (8.37 g, 62 mmol) so that the temperature did not
increase over 245 uC. The mixture was stirred for 1 h at
245 uC. Afterwards the mixture was allowed to warm up to
room temperature and stirred for an additional 24 hours.
The reaction mixture was quenched with 20 ml water and the
organic phase was separated. The water phase and the
inorganic solid material were washed with 100 ml of diethyl
ether. The combined organic phases were dried over MgSO4
and filtered through a small column with silica gel. The
solution was concentrated. By addition of hexane at 0 uC
orange crystals were obtained. Yield: 3.36 g (65%)
1
Fig. 6 Output characteristic of a device prepared from BT7 as the
2 2 4
H NMR d(400 MHz, C D Cl ): 7.23 (dd, 2H, J = 3.3 Hz,
semiconducting layer.
J = 5.0 Hz), 7.20 (dd, 2H, J = 1.2 Hz, J = 3.2 Hz), 6.97 (dd,
1
3
2
H, J = 1.4 Hz, J = 5.1 Hz). C NMR d(100 MHz, C
30.3, 127.2, 123.2, 110.3. MS (EI, 70 eV): m/z = 166 (M ).
: C, 57.79; H, 3.64; S, 38.57. Found: C,
7.48; H, 3.88; S, 38.33%.
2 2 4
D Cl ):
2
,29,5,59-tetrabromo-3,39-bithienyl with mono-stannylated
+
1
(
oligo)thiophenes. Compared to the well-known unsubstituted
8 6 2
Anal. Calcd. for C H S
8
linear oligothiophenes the solubility of the swivel-cruciform
oligothiophenes is substantially increased. However, the
solubility of the dimers also decreases with increasing length
of the oligothiophene arms. Such swivel-cruciform dimers
allow solution processing without addition of alkyl side chains.
5
2
,29,5,59-Tetrabromo-3,39-dithienyl (2). 3,39-Dithienyl (1.03 g,
.2 mmol) (1) and N-bromosuccinimide (5.52 g, 31 mmol) were
6
dissolved in 100 ml of dry THF and stirred for 48 h at room
temperature. The solvent was removed and hexane was added.
Insoluble byproducts were removed by filtration and the
solvent was removed. The residue was purified by column
chromatography on silica gel with hexane as eluent to give 2 as
white crystals. Yield: 0.93 g (31%).
2
5
2
21 21
We obtained a field-effect mobility of 3.7 6 10 cm V
s
3
and a current on/off ratio of .10 for a solution-processed
OFET device with dimer BT5 as p-type semiconductor. At the
moment, we are looking for related cruciforms with improved
OFET performance.
1
13
H NMR d(400 MHz, C D Cl ): 6.97 (s, 2H). C NMR
2
2
4
Experimental
2 2 4
d(100 MHz, C D Cl ): 135.2, 131.6, 111.5, 111.2. MS (EI,
+
0 eV): m/z = 482 (M ). Anal. Calcd. for C
7
8 2 4 2
H Br S : C, 19.94;
Instrumentation
H, 0.42; S, 13.31. Found: C, 19.90; H 0.82; S, 13.53%.
1
13
The H and C NMR spectra were recorded on a Bruker
ARX 400 spectrometer with deuterated tetrachlorethane as the
solvent. Low-resolution Mass Spectrometry was carried out on
a Varian MAT 311 A operating at 70 eV (electron impact) and
reported as m/z. Field Desorption Mass Spectrometry was
done with a VG Instruments ZAB 2-SE-FPD and reported as
m/z. Elemental analyses were performed on a Vario EL II
5-Trimethylstannyl-2,29-dithienyl (3). To
a solution of
2,29-bithiophene (4 g, 24 mmol) in 150 ml of dry THF
N,N,N9,N9-tetramethylethylenediamine (2.94 ml, 24.4 mmol)
was added at 278 uC. Subsequently, a 2.5 M solution of
n-BuLi in hexane (9.76 ml, 24.4 mmol) was added dropwise.
After complete addition the mixture was stirred for 1 h at
room temperature. The solution was cooled at once to 278 uC
and trimethylstannylchloride (4.85 g, 24.4 mmol) was added.
Finally, the mixture was stirred at room temperature for 1 h.
(
CHNS) instrument. UV-Vis absorption spectra were recorded
on a Jasco V 550 spectrophotometer. Fluorescence measure-
ments were carried out on a Varian Cary Eclipse instrument.
3
180 | J. Mater. Chem., 2006, 16, 3177–3182
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The solution was poured into ice and extracted subsequently
with 150 ml of diethyl ether. The organic phase was washed
Bis(pentathiophene) BT5 (6). A 250 ml flask was charged
with 2,29,5,59-tetrabromo-3,39-dithienyl (1 g, 2.1 mmol),
5-trimethylstannyl-2,29-dithienyl (2.77 g, 8.4 mmol) and
tetrakis(triphenylphosphino)palladium (0.098 g, 0.083 mmol)
and filled with argon. The mixture was added to 100 ml of dry
toluene and was refluxed for 24 h in the dark. Then 2 ml
of 4 M HCl in 1,4-dioxane were added. The mixture was
extracted with chloroform and the organic phase subsequently
washed with dilute aqueous HCl, saturated aqueous EDTA
4
with water, dried over MgSO and the solvent removed. The
crude product was purified by column chromatography on
aluminium oxide and cyclohexane as the eluent to give 3 as a
colorless oil. Yield: 6.35 g (80%).
1
2 2 4
H NMR d(400 MHz, C D Cl ): 7.23 (t, 1H, J = 3.8 Hz),
7
.14 (m, 2H), 7.04 (t, 1H, J = 3.3 Hz), 6.96 (td, 1H, J = 3.8 Hz,
1
J = 4.8 Hz), 0.34 (d, 9H, J = 2.3 Hz). C NMR d(100 MHz,
3
C D Cl ): 143.0, 138.0, 137.7, 136.3, 128.2, 125.4, 124.6, 123.9,
2
solution, saturated NaHCO
3
solution and brine. The solution
2
4
+
2
7.8. MS (EI, 70 eV): m/z = 329 (M ). Anal. Calcd. for
Sn: C, 40.15; H, 4.29; S, 19.49. Found: C, 39.89; H,
.63; S, 19.56%.
was dried over MgSO and the solvent removed by rotary
4
C
11
H
14
S
2
evaporation. The crude product was redissolved in chloroform
and precipitated into a methanol–aqueous HCl mixture (95 : 5)
4
to give 6 as a red powder. Yield: 0.81 g (47%).
1
2-Tri(n-butyl)stannylterthiophene (4). To
a
solution of
H NMR d(400 MHz, C D Cl ): 7.19 (dd, 2H, J = 1.2 Hz,
2 2 4
terthiophene (2 g, 8 mmol) in 100 ml of dry THF, a 2.5 M
solution of n-BuLi in hexane (3.2 ml, 8 mmol) was added
dropwise at 0 uC. The mixture was stirred for 1 h at room
temperature. Afterwards the solution was cooled to 0 uC
and tri(n-butyl)stannyl chloride (2.6 g, 8 mmol) was added.
Finally, the mixture was stirred at room temperature for 1 h.
Afterwards the reaction mixture was poured into ice and
extracted with dichloromethane. The organic phase was
J = 5.1 Hz), 7.13 (ddd, 4H, J = 0.9 Hz, J = 4.3 Hz, J = 6.0 Hz),
7.10 (d, 2H, J = 3.8 Hz), 7.05 (dd, 4H, J = 4.5 Hz, J = 7.5 Hz),
7.02 (dd, 2H, J = 0.9 Hz, J = 3.5 Hz), 6.98 (dd, 2H, J = 3.6 Hz,
1
3
J = 5.1 Hz), 6.91 (td, 6H, J = 3.6 Hz, J = 6.9 Hz). C NMR
d(100 MHz, C Cl ): 138.1, 137.2, 137.1, 137.0, 135.8, 135.4,
134.6, 134.3, 132.6, 128.2, 128.1, 127.0, 126.4, 125.1, 125.0,
2
D
2
4
124.9, 124.8, 124.3, 124.2, 124.2. MS (FD, 70 eV): m/z = 823
+
(M ). Anal. Calcd. for C40
H
22
S10: C, 58.36; H, 2.69; S, 38.95.
washed with brine and the organic phase dried over MgSO
4
.
Found: C, 58.03; H, 2.99; S, 38.53%.
The solvent was removed and the yellowish oil purified by
column chromatography on silica gel with a 9 : 1 mixture of
hexane–ethyl acetate as the eluent to give 4 as a colourless oil.
Bis(heptathiophene) BT7 (7). A 250 ml flask was charged
with 2,29,5,59-tetrabromo-3,39-dithienyl (0.25 g, 0.56 mmol),
2-tri(n-butyl)stannylterthiophene (1.22 g, 2.3 mmol) and the
tetrakis(triphenylphosphino)palladium (0.053 g, 0.045 mmol)
and filled with argon. Dry toluene (100 ml) was added and the
mixture was refluxed for 24 h in the dark. Then 2 ml of 4 M
HCl in 1,4-dioxane were added. The mixture was extracted
with chloroform and subsequently washed with dilute aqueous
Yield: 1.45 g (34%).
1
2 2 4
H NMR d(400 MHz, C D Cl ): 7.23 (d, 1H, J = 3.3 Hz),
7
6
6
.17 (d, 1H, J = 5.1 Hz), 7.11 (d, 1H, J = 3.5 Hz), 7.01 (m, 3H),
.97 (dd, 1H, J = 3.7 Hz, J = 5.0 Hz), 1.52 (m, 6H), 1.29 (m,
1
H), 1.07 (m, 6H) 0.85 (t, 9H, J = 7.3 Hz). C NMR
3
d(100 MHz, C D Cl ): 142.4, 137.7, 137.4, 136.8, 136.5, 135.9,
2
2
4
1
28.3, 125.3, 124.8, 124.7, 124.4, 124.0, 29.2, 27.5, 14.0, 11.3.
+
HCl, saturated aqueous EDTA solution, saturated NaHCO
solution and brine. The solution was dried over MgSO
3
4
34 3
MS (EI, 70 eV): m/z = 538 (M ). Anal. Calcd for C24H S Sn:
C, 53.64; H, 6.38; S, 17.90. Found: C, 53.50; H, 6.29; S, 18.0%.
and the solvent removed by rotary evaporation. The crude
product was redissolved in chloroform and precipitated into a
methanol–aqueous HCl mixture (95 : 5) to give 7 as a red
powder. Yield: 0.31 g (48%). Due to the low solubility of 7 we
Bis(terthiophene) BT3 (5). 2,29,5,59-Tetrabromo-3,39-dithie-
nyl (1.13 g, 2.4 mmol), 2-tri(n-butyl)stannylthiophene (3.86 g,
1
3
1
0
0.3 mmol) and tetrakis(triphenylphosphino)palladium (0.1 g,
,086 mmol) were dissolved in 80 ml of dry toluene. The
could not record a C NMR spectrum.
1
H NMR d(400 MHz, C D Cl ): 7.19 (d, 2H, J = 5.2 Hz),
2 2 4
mixture was refluxed for 48 h in the dark. The reaction was
quenched with 2 ml of 4 M HCl in 1,4-dioxane. The mixture
was extracted with chloroform and the organic phase
subsequently washed with dilute aqueous HCl, saturated
7.14 (m, 6H), 7.09 (m, 4H), 7.06 (d, 6H, J = 8.7 Hz), 6.98 (m,
+
4H), 6.93 (m, 8H). MS (FD, 70 eV): m/z = 1149.8 (M ). Anal.
30
Calcd for C58H S14: C, 58.40; H, 2.63; S, 38.98. Found: C,
58.06; H 2.31; S, 39.13%.
aqueous EDTA solution, saturated aqueous NaHCO
and brine. The organic phase was dried over MgSO
3
solution
and the
4
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2
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1
3
4
5
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2 2 4
H NMR d(400 MHz, C D Cl ): 7.20 (dd, 2H, J = 0.9 Hz,
J = 5.1 Hz), 7.18 (d, 2H, J = 3.7 Hz), 7.09 (dd, 2H, J = 0.9 Hz,
J = 5.1 Hz), 7.02 (s, 2H), 7.00 (td, 4H, J = 2.3 Hz, J = 6.6 Hz),
1
3
6
.85 (dd, 2H, J = 3.7 Hz, J = 5.1 Hz). C NMR d(100 MHz,
Cl ): 137.1, 135.8, 135.5, 134.4, 132.7, 128.2, 127.4, 127.1,
26.3, 125.6, 125.1, 124.3. MS (EI, 70 eV): m/z = 496 (M ).
Anal. Calcd. for C24 : C, 58.26; H, 2.85; 38.79. Found: C,
8.37; H, 2.78; S, 38.85%.
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2, L412–L567.
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2
C
D
2 2
4
+
1
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R. de Bettingnies, Y. Nicolas, P. Blanchard, E. Levillian,
J.-M. Nunzi and J. Roncalli, Adv. Mater., 2003, 22, 1939.
14 6
H S
8
5
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