Bistriphenylamine-substituted fluoranthene derivatives as electroluminescent emitters and dye-sensitized solar cells

Article abstract of DOI:10.1016/j.tet.2012.09.013

A novel series of compounds containing fluoranthene and triphenylamine were designed and synthesized as electroluminescent materials or sensitizers. Photophysical and electrochemical measurements were carried out on these compounds. DPBF exhibited a maximum current efficiency of 1.3 cd/A (1.00 lm/W at 5.17 V) and D2 had the maximum light-to-electricity efficiency of 4.57% under AM 1.5 solar simulator (100 mW cm^-2). The results suggest that bistriphenylamine-substituted fluoranthene derivatives have the potential application in optoelectronic materials.

Full text of DOI:10.1016/j.tet.2012.09.013

Tetrahedron 68 (2012) 10372e10377
Contents lists available at SciVerse ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Bistriphenylamine-substituted fluoranthene derivatives as electroluminescent
emitters and dye-sensitized solar cells
*
Tonghai Wang, Jinlong Han, Zhiyun Zhang, Bo Xu, Jinhai Huang, Jianhua Su
Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science & Technology, Shanghai 200237, China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 14 May 2012
Received in revised form 26 August 2012
Accepted 4 September 2012
Available online 10 September 2012
A novel series of compounds containing fluoranthene and triphenylamine were designed and synthe-
sized as electroluminescent materials or sensitizers. Photophysical and electrochemical measurements
were carried out on these compounds. DPBF exhibited a maximum current efficiency of 1.3 cd/A
(1.00 lm/W at 5.17 V) and D2 had the maximum light-to-electricity efficiency of 4.57% under AM 1.5 solar
simulator (100 mW cmꢀ2). The results suggest that bistriphenylamine-substituted fluoranthene de-
rivatives have the potential application in optoelectronic materials.
Keywords:
Ó 2012 Elsevier Ltd. All rights reserved.
Substituted fluoranthene
Triphenylamine
OLED
DSSC
1. Introduction
of bistriphenylamine-substituted fluoranthene derivatives (shown
in Fig. 1). We synthesized 4,40-(benzo[k]fluoranthene-7,12-diyl)
Organic optoelectronic materials have attracted much attention
in recent years, due to their essential role for optoelectronic de-
vices, such as light-emitting diodes (OLEDs)1 and dye-sensitized
solar cells (DSSCs).2 Unlike the conventional inorganic materials,
the organic materials have showed obvious advantages of low cost,
easy preparation, flexibility and so on. To date, a large number of
novel organic photoelectric conversion materials have been de-
veloped and optimized, in order to achieve superior performance.3
Fluoranthene and its derivatives, one kind of polycyclic aromatic
hydrocarbons (PAHs) with excellent fluorescent emission and car-
rier transport capacity, are of great interest in optoelectronic area.4
Hence, numerous fluoranthene-based PAH-type materials have
been designed and investigated extensively for their potential ap-
plication as organic nonlinear optical materials (NLO),5 fluorescent
sensors,6 OLEDs,7 and DSSCs.8 More recently, we have applied
benzo[k]fluoranthene derivatives into OLEDs9 and DSSCs10 and
found that they can exhibit good performance in the area of op-
toelectronic materials.8,11
bis(N,N-diphenylaniline) (DPBF), and fabricated it into three OLED
devices. Meanwhile, we employed the organic sensitizers D-D-p-A
design concept13 and synthesized a series of dyes D1, D2, and D3,
expecting that the extra triphenylamine moiety in dyes can form
a tightly packed insulating monolayer blocking the Iꢀ3 or cations
approaching the TiO2. They have been successfully applied to the
As we know, triphenylamine derivatives, due to their out-
standing thermal stability, mechanical property, and electron-
donating ability, have become more and more important in the
field of organic optoelectronics.12 Based on the merits of combining
fluoranthene and triphenylamine in one unit, we designed a series
* Corresponding author. Tel./fax: þ86 21 64252288; e-mail address: bbsjh@
ecust.edu.cn (J. Su).
Fig. 1. Molecular structures of DPBF and D1eD3.
0040-4020/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2012.09.013

T. Wang et al. / Tetrahedron 68 (2012) 10372e10377
10373
sensitization of nanocrystalline TiO2-based solar cells and the cor-
2.2. Photophysical properties
responding photovoltaic properties, electronic and optical proper-
ties are also presented.
The UVevis absorption and fluorescence spectra of all com-
pounds in dilute CH2Cl2 solution are shown in Fig. 2 (Table 1). The
four compounds have very similar absorption properties. The
lowest absorption maxima for them occur at 375e447 nm, and are
2. Results and discussions
2.1. Synthesis
assigned to the pep transition of conjugated molecular backbone.
*
Compared to D3, the absorption band of D2, bearing a thiophene
moiety instead of a phenyl ring, presented red-shift absorption and
The synthetic route to these compounds containing the
bistriphenylamine-substituted fluoranthene is depicted in Scheme 1.
The synthesis of these dyes was similar to the procedures reported
before.14 Compound 1 was prepared by FriedeleCrafts acylation.
Then it was deoxidized and compound 2 was generated by intra-
molecular esterification. Compound 3 was obtained by Grignard
reaction. DPBF and compounds 4 and 5 were synthesized and puri-
fied according to the established procedure.15 In the next step, the
bromo-exposed intermediate 4 was reacted with 5-formylthiophen-
2-ylboronicacid or 4-formylphenylboronic acid by Suzuki coupling
reaction.16 Finally, the target products (D1eD3) were synthesized via
the Knoevenagel condensation reaction of aldehydes 5, 6, and 7 with
cyanoacetic acid in the presence of acetic acid and ammonium ace-
tate. All thekey intermediates andfour finalproducts (DPBF, D1eD3)
were confirmed by 1H NMR, 13C NMR, and high-resolution mass
spectrometry.
higher maximum extinction coefficients ( max), suggesting that the
3
thiophene unit is more effective in increasing conjugation than the
phenyl.17 In D3, there is a larger dihedral angle due to HeH steric
hindrance effect from fluoranthene and benzene. However, the
dihedral angle between fluoranthene and thiophene in D2 is
smaller to result in a larger conjugation length. Upon irradiation at
447, 445, 426, and 430 nm, the PL spectra of D1eD3 and DPBF in
solution were found to exhibit emission with the peak maxima at
470, 608, 611, and 590 nm, respectively. The quantum yields of
these compounds in CH2Cl2 solution have been measured and
summarized in Table 1.
The absorption spectra of D1eD3 on TiO2 films after 18 h ad-
sorption are shown in Fig. 3. The maximum absorption peaks of
D1eD3 on the TiO2 film are at 440, 419, and 437 nm, respectively.
Compared to those of the corresponding solution spectra, the
Scheme 1. The synthetic routes of DPBF and D1eD3.

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T. Wang et al. / Tetrahedron 68 (2012) 10372e10377
and 1.10 V versus NHE, respectively. The HOMO levels of the three
dyes are much more positive than the iodine/iodide redox potential
value (0.4 V), ensuring that there is enough driving force for the dye
regeneration efficiently through the recapture of the injected
electrons from Iꢀ by the dye cation radical. The excitation transition
energies (E0e0) of D1eD3 estimated from their absorption thresh-
olds of dyes-sensitized TiO2 films are 2.27, 2.28, and 2.43 eV, re-
spectively. The estimated excited state potential corresponding to
the LUMO levels of D1eD3, calculated from EHOMOꢀE0e0, are ꢀ1.21,
ꢀ1.20, and ꢀ1.33 V versus NHE, respectively. The LUMO levels of
the dyes are sufficiently more negative than the conduction-band-
edge energy level (Ecb) of the TiO2 electrode (ꢀ0.5 V vs NHE), which
implies that electron injection from the excited dyes into the con-
duction-band of TiO2 is feasible.20
2.4. Application in OLED
To study the electroluminescent performance of DPBF, we fab-
ricated three devices (1e3), with the following device configura-
Fig. 2. Normalized absorption and PL spectra of compounds DPBF and D1eD3.
Table 1
Optical and electrochemical properties of DPBF and D1eD3
UV
max
FL
max
Dye
l
a/nm (
3
ꢂ10ꢀ4 Mꢀ1 cmꢀ1
)
lmaxb/nm
l
a,c/nm
Ffa,d
HOMOe/V
E0e0f/eV
LUMOg/V
DPBF
D1
D2
325, 375, 425
d
470
608
611
590
0.66
0.13
0.03
0.02
ꢀ5.14(eV)
1.06
1.08
2.88
2.27
2.28
2.43
ꢀ2.26(eV)
ꢀ1.21
297(5.8), 447(1.2)
300(5.4), 445(2.1)
303(5.1), 426(1.4)
440
439
417
ꢀ1.20
D3
1.10
ꢀ1.33
a
As measured in CH2Cl2 solution.
Absorption maximum on TiO2 film.
DPBF and D1eD3 are excited at 447, 445, 426, and 430 nm, respectively.
DPBF, with anthracene in ethanol (Ff¼0.31) as standard and D1eD3, with rhodamine B in ethanol (Ff¼0.89) as a standard.
HOMO of DPBF(eV) was measured in CH2Cl2 solution and HOMO of D1eD3(vs NHE) was measured on TiO2 film.
E0e0 of D1eD3 was estimated from the absorption thresholds from absorption spectra of dyes adsorbed on the TiO2 film.
LUMO is estimated by subtracting E0e0 to HOMO.
b
c
d
e
f
g
absorption peaks of the dyes on the TiO2 films are slightly blue-
tions: ITO/CFx/NPB (50 nm)/DPBF(40 nm)/TPBI (15 nm)/LiF (1 nm)/
Al (device 1); ITO/CFx/NPB (50 nm)/DPBF (40 nm)/TPBI (40 nm)/LiF
(1 nm)/Al (device 2); ITO/CFx/DPBF (40 nm)/TPBI (40 nm)/LiF
(1 nm)/Al (device 3), where indium tin oxide (ITO) was used as the
anode, polymerized fluorocarbon (CFx) was the hole-injection
layer, 4,40-bis[N-(1-naphthyl)-N-phenyl-1-amino]biphenyl (NPB)
was used as the hole transporting layer, 1,3,5-tris(N-phenyl-
benzimidazol-2-yl)benzene (TPBI) was used as the electron
injecting layer. The detailed device structures are shown in Fig. S1.
Additionally we tested DPBF’s thermal property and it exhibits high
thermal stabilities with decomposition temperature (Td) over
510 ꢁC, which is helpful to improve the device lifetime. However, no
glass transition was observed in differential scanning calorimetry.
The current densityevoltageeluminance (IeVeL) characteris-
tics for the devices 1e3 are shown in Fig. S2. The device 1 presented
hole transporting layer (NPB) and the decreasing thickness of
electron transporting layer (TPBI). Meanwhile, from the device 3,
we can also find that DPBF showed good hole transporting prop-
erty. Detailed EL performances of all the three devices were sum-
marized in Table 2 and device 1 showed the highest efficiency
among the three types of devices. The maximum current and
power efficiencies of device 1 were 1.30 cd/A and 1.00 lm/W with
a maximum luminance of 1254 cd/m2 at 15 V, respectively.
shifted, which is probably due to the H-aggregation.18,19
2.3. Electrochemical properties
The HOMO levels and LUMO levels measured by cyclic voltam-
metry are listed in Table 1. The HOMO value of DPBF measured in
CH2Cl2 is ꢀ5.14 eV, and its LUMO value calculated from the optical
band gap and the HOMO value, is ꢀ2.26 eV. The HOMO levels of
D1eD3 corresponding to their first redox potential are 1.06, 1.08,
2.5. Application in DSSC
To investigate the sensitized performance of D1eD3, we fabri-
cated them into a sandwich-type two-electrode cells. Fig. 4 shows
the action spectra of incident photo-to-current conversion effi-
ciency (IPCE) for DSSCs with D1eD3. The dye-coated TiO2 film was
used as working electrode, platinized FTO glass as the counter
Fig. 3. Normalized absorption spectra of dyes on TiO2 film.

T. Wang et al. / Tetrahedron 68 (2012) 10372e10377
10375
Table 2
EL performance of devices 1e3
lEL(fwhm)e CIEx,y
(cd/m2) (nm)
a
b
d
Device Von (V) hl,max
hp,maxc (lm/W) Lmax
(cd/A)
1
2
3
5.17
4.39
4.55
1.30
1.36
0.98
1.00
0.97
0.60
1254
943
717
464(84)
460(68)
476(76)
0.18, 0.25
0.18, 0.19
0.18, 0.26
a
b
c
Turn-on voltage at which emission starts to be detectable.
Maximum current efficiency.
Maximum power efficiency.
Maximum luminance.
Full-width at half-maximum.
d
e
Fig. 5. Photocurrent density versus voltage curves of DSSCs sensitized by the dyes
D1eD3 with electrolyte containing 0.1 M LiI, 0.05 M I2, 0.6 M PMII, 0.5 M TBP in the
mixed solvent of acetonitrile and 3-methoxypropionitrile (7:3, v/v) under light
(100 mW cmꢀ2 simulated AM 1.5 G solar light) and dark.
Table 3
Optical properties and performance parameters of dye-sensitized solar cells of
D1eD3a
Dye
Jsc/mA cmꢀ2
Voc/V
ff
h/%
D1
D2
D3
N79
7.59
8.57
5.56
0.73
0.76
0.69
0.74
0.72
0.70
0.69
0.63
4.00
4.57
2.72
8.00
17.41
Illumination: 100 mW cmꢀ2 simulated AM 1.5 G solar light; electrolyte con-
taining: 0.1 M LiIþ0.05 M I2þ0.6 M PMIIþ0.5 M TBP in the mixed solvent of aceto-
nitrile and 3-methoxypropionitrile (7:3, v/v).
a
Fig. 4. Photocurrent action spectra of the TiO2 electrodes sensitized by D1eD3.
electrode, and 0.6 M PMII, 0.05 M I2, 0.10 M LiI, and 0.5 M 4-tert-
butylpyridine in acetonitrile and methoxypropionitrile (volume
ratio, 7:3) mixture solution as the redox electrolyte. As shown in
Fig. 4, D2 has more efficiency converting visible light to photocur-
rent in the region from 400 to 600 nm, which reaches its maximum
of 70% at 450 nm. The IPCE of D1 and D3 is less than 60% in the
spectral range 400e600 nm, which reach their maximum at 450
and 440 nm, respectively. The rather high IPCE value for D2 dye
indicates that thiophene is a good link bridge in DSSC.
findings show that device 1 with hole transporting layer and thin
electron injecting layer achieves better EL performance. We also
obtained a maximum solar energy to electricity conversion effi-
ciency of 4.57% (Jsc¼8.57 mA cmꢀ2, Voc¼0.76 V, ff¼0.70) under AM
1.5 solar simulator (100 mW cmꢀ2) based on D2 and the future
improvement of the power conversion efficiency in dye-based TiO2
cell will be possible by modification of the structure, and these
works are now in progress.
The currentevoltage characteristics of DSSCs fabricated with
these dyes (D1eD3) as sensitizers under standard global AM 1.5
solar light condition are presented in Fig. 5. The detailed parame-
ters of short-circuit current density (Jsc), open-circuit voltages (Voc),
4. Experiment section
4.1. General information
fill factor (ff), and photovoltaic conversion efficiency (h) are sum-
13
1H NMR and C NMR spectra were recorded on a Bucker AM
marized in Table 3. D2 has the highest light-harvesting efficiency
and short-circuit current Jsc among the three dyes, as the Jsc is re-
lated to the molar extinction coefficient of the dye molecule, in
which a higher molar extinction coefficient has good light-
harvesting ability and yields a higher short circuit. Compared
with D3, D1 has a little lower molar extinction, but its photovoltaic
performance is higher than D3.
This is probably because D1 has a much higher maximum values
of IPCE spectrum than D3, which can be attributed to the good
injection efficiency of D1 and its HOMO might be beneficial for
retarding the electron transfer from TiO2 to the oxidized dye or
electrolyte.
€
400 spectrometer. Mass spectra were measured with an HP5989
mass spectrometer. The UVevis spectra were recorded with a Var-
ian Cary 500 spectrophotometer and fluorescence emission spectra
were conducted on Varian Cary Eclipse fluorescence spectropho-
tometer. Cyclic voltammograms were performed with a Versastat II
electrochemical workstation. The differential scanning calorimetry
(DSC) analysis was performed under a nitrogen atmosphere on a TA
Instruments DSC 2920. Thermogravimetric analysis was un-
dertaken using a TGA instrument. To measure the fluorescence
quantum yields (Ff), degassed solutions of the compounds in
CH2Cl2 were prepared. Rhodamine B in ethanol (Ff¼0.89) and
anthracene in ethanol (Ff¼0.31) were used as standard. Detailed
device fabrications and the photoelectrochemical measurements
are written in Supplementary data. Fluorine-doped SnO2 con-
ducting glass (FTO glass, transmission >90% in the visible,
3. Conclusion
In summary, we have synthesized a series of bistriphenylamine-
substituted fluoranthene derivatives, which can be used as DSSC or
OLED materials and studied their electro-optical properties. Our
sheet resistance 15
U/square) was obtained from Geao Science
and Educational Co. Ltd. of China. Tetra-n-butylammonium

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T. Wang et al. / Tetrahedron 68 (2012) 10372e10377
hexafluorophosphate (TBAPF6), 4-tert-butylpyridine (4-TBP), and
lithium iodide were bought from Fluka and iodine, 99.999%, was
purchased from Alfa Aesar. All other solvents and chemicals used
were produced by Sinopharm Chemical Reagent Co., Ltd., China
(reagent grade) and used as received. Solvents were distilled from
appropriate reagents.
(d, J¼7.2 Hz, 1H), 6.66e6.68 (d, J¼7.6 Hz, 1H). HRMS (m/z): [MþH]þ
calcd for C56H37BrN2: 817.2218, found: 817.2237.
4.2.5. 7,12-Bis(4-(diphenylamino)phenyl)benzo[k]fluoranthene-3-
carbaldehyde (5). A procedure similar to that for the compound 4
but with acenaphthylene-5-carbaldehyde (0.45 g, 2.5 mmol) in-
stead of 5-bromoacenaphthylene giving the compound
5 as
a yellow solid (1.34 g, 70%). 1H NMR (400 MHz, CDCl3,
d
): 10.35 (s,
4.2. Synthesis
1H), 8.83e8.85 (d, J¼8.4 Hz, 1H), 7.91e7.92 (d, J¼7.6 Hz, 1H),
7.76e7.79 (m, 2H), 7.46e7.56 (m, 3H), 7.35e7.39 (m, 16H),
7.29e7.31 (m, 8H), 7.08e7.13 (dd, J1¼7.2 Hz, J2¼12 Hz, 4H),
6.94e6.96 (d, J¼7.2 Hz, 1H), 6.87e6.89 (d, J¼7.2 Hz, 1H). 13C NMR
4.2.1. 2-(4-(Diphenylamino)benzoyl)benzoic acid (1). Phthalic an-
hydride (7.4 g, 50 mmol), anhydrous aluminum chloride (8.67 g,
65 mmol), and dry CH2Cl2 (150 mL) were added to a three-neck
flask. The mixture was stirred for 1 h at room temperature and
was treated dropwise with a solution of triphenylamine (10.23 g,
41.7 mmol) in CH2Cl2 (50 mL) at 0 ꢁC. After the addition was com-
plete, the reaction mixture was stirred for another 4 h at room
temperature, poured over ice-contained HCl solution, and extracted
with CH2Cl2. The organic layer was collected, dried over anhydrous
Na2SO4. It was purified by column chromatography on silica
(CH2Cl2/petrol ether¼4:1) to yield 1 as a white solid (12.30 g, 75%).
(100 MHz, CDCl3, d): 193.11, 147.88, 147.72, 147.69, 143.54, 138.11,
136.95, 136.90, 136.13, 135.44, 135.13, 134.02, 133.58, 133.25,
131.76, 131.52, 130.73, 130.68, 130.60, 130.37, 129.55, 129.51, 127.57,
127.35, 127.05, 126.78, 126.22, 124.88, 124.79, 124.58, 123.86,
123.63, 123.42, 123.30, 123.14, 120.94. HRMS (m/z): [MþH]þ calcd
for C57H38N2O: 767.3062, found: 767.3065.
4.2.6. 4,40-(Benzo[k]fluoranthene-7,12-diyl)bis(N,N-diphenylaniline)
(DPBF). A procedure similar to that for the compound 4 but with
acenaphthylene (0.76 g, 5 mmol) instead of acenaphthylene-5-
carbaldehyde giving the compound DPBF as a yellow-green solid
1H NMR (400 MHz, CDCl3,
d
): 8.08e8.10 (d, J¼7.6 Hz, 1H), 7.61e7.65
(t, 1H), 7.51e7.57 (m, 3H), 7.37e7.38 (d, J¼7.2 Hz, 1H), 7.29e7.32 (t,
4H), 7.11e7.17 (m, 6H), 6.91e6.93 (d, J¼8.4 Hz, 1H). HRMS (m/z):
[MþH]þ calcd for C26H19NO3: 394.1443, found: 394.1449.
(1.23 g, 68%). 1H NMR (400 MHz, CDCl3,
d): 7.79e7.81 (m, 2H),
7.74e7.76 (d, J¼8 Hz, 2H), 7.29e7.47 (m, 28H), 7.07e7.11 (t, J¼7.2 Hz,
4H), 6.88e6.90 (d, J¼6.8 Hz, 2H). 13C NMR (100 MHz, CDCl3,
d):
4.2.2. 3-(4-(Diphenylamino)phenyl)isobenzofuran-1(3H)-one (2). A
solution of compound 1 (11.8 g, 30 mmol) inTHF/EtOH (2:5) (140 mL)
was treated with NaBH4 (5.67 g,150 mmol) inportions.Itwas refluxed
for 12 h, cooled to room temperature, and then cautiously acidified
with 12% aqueous hydrochloric acid to pH 2. The mixture was stirred
for 1 h at room temperature, and extracted with EtOAc. The organic
layer was collected, dried over anhydrous MgSO4. It was purified by
column chromatography on silica (hexane/EtOAc¼9:1) to yield 2 as
147.82, 147.54, 136.82, 135.66, 135.07, 134.70, 133.12, 132.63, 130.90,
130.19, 129.44, 129.31, 127.84, 126.88, 125.94, 125.78, 124.63, 124.49,
124.31, 124.12, 124.01, 123.11, 122.99, 122.24. HRMS (m/z): [MþH]þ
calcd for C56H38N2: 739.3113, found: 739.3121.
4.2.7. 3-(7,12-Bis(4-(diphenylamino)phenyl)benzo[k]fluoranthen-3-
yl)-2-cyanoacrylic acid D1. Compound
5 (0.77 g, 1 mmol), 2-
cyanoacetic acid (0.6 g, 7 mmol), and ammonium acetate
(100 mg) were refluxed in acetic acid (15 mL) at 120 ꢁC for 12 h.
After cooling the solution, water was added to quench the reaction.
The precipitate was filtered and washed with water. The residue
was purified by column chromatography on silica gel (CH2Cl2/
CH3OH¼20:1) to yield D1 as an orange solid (0.67 g, 81%). 1H NMR
a white solid (7.65 g, 68%). 1H NMR (400 MHz, CDCl3,
d): 7.95e7.97 (d,
J¼7.6 Hz, 1H), 7.65e7.69 (t, 1H), 7.54e7.58 (t, 1H), 7.37e7.39 (d,
J¼7.6 Hz, 1H), 7.24e7.28 (t, 4H), 7.01e7.09 (m, 10H). HRMS (m/z):
[MþH]þ calcd for C26H19NO2: 378.1494, found: 378.1499.
4.2.3. 4,40-(Isobenzofuran-1,3-diyl)bis(N,N-diphenylaniline) (3). 4-
Bromo-N,N-diphenylaniline (9.73 g, 30 mmol) with dry THF(25 mL)
was added slowly to a refluxing mixture of magnesium turnings
(0.87 g, 36 mmol) and iodine (10 mg) in dry THF(20 mL) under ar-
gon. After the formation of the Grignard reagent (1 h reflux), the
cooled reagent was added slowly via an addition funnel to a solu-
tion of lactone 2 (7.55 g, 20 mmol) in THF (50 mL) at 0 ꢁC. The re-
action mixture was stirred for 6 h at room temperature and was
acidified with HCl. The mixture was stirred for 15 min at room
temperature, and extracted with CH2Cl2. The organic layer was
collected, dried over anhydrous MgSO4, and evaporated under re-
duced pressure. The crude product was purified by column chro-
matography on silica (hexane) to yield 3 as an orange solid (6.05 g,
50%). The intermediate is unstable, so we have no characterization
data.
(400 MHz, DMSO-d6,
d
): 8.74 (s, 1H), 8.10e8.12 (d, J¼7.6 Hz, 1H),
7.82e7.84 (d, J¼6.8 Hz, 1H), 7.60e7.65 (m, 2H), 7.48e7.50 (m, 3H),
7.38e7.43 (m, 8H), 7.10e7.32 (m, 20H), 6.62e6.68 (m, 2H). 13C NMR
(100 MHz, DMSO-d6, d): 147.19, 147.05, 147.01, 138.67, 136.07, 135.21,
134.53, 134.45, 134.04, 133.30, 132.75, 132.32, 131.28, 131.01, 130.44,
130.35, 130.26, 129.81, 129.63, 129.51, 129.01, 128.97, 128.38, 128.32,
127.94, 126.72, 126.64, 126.42, 124.31, 124.10, 123.88, 123.36, 123.28,
122.10, 120.83. HRMS (m/z): [MþH]þ calcd for C60H39N3O2:
834.3121, found: 834.3116.
4.2.8. 5-(7,12-Bis(4-(diphenylamino)phenyl)benzo[k]fluoranthen-3-
yl)thiophene-2-carbaldehyde (6). A stirred mixture of 4 (0.41 g,
0.50 mmol),
5-formylthiophen-2-ylboronicacid
(0.078 g,
0.50 mmol), Pd(PPh3)4 (0.0075 g, 0.0065 mmol), Na2CO3 (65 mg,
0.6 mmol), THF(10 mL), and H2O (2 mL) was heated at reflux for
12 h. When the reaction was completed, water was added and the
reaction mixture was extracted three times with CH2Cl2. The
combined organic layer was washed with H2O and brine, dried over
anhydrous Na2SO4, and evaporated under reduced pressure. The
crude product was purified by column chromatography on silica
(hexane/CH2Cl2¼1:1) to yield 6 as an orange solid (0.21 g, 49%). 1H
4.2.4. 4,40-(3-Bromobenzo[k]fluoranthene-7,12-diyl)bis(N,N-diphe-
nylaniline) (4). Compound 3 (3.02 g, 5 mmol) and 5-bromoace-
naphthylene (1.16 g, 5 mmol) were refluxed in toluene (30 mL) for
24h. After cooling to room temperature, trifluoroacetic acid (0.78
mL) was added and heated at 60 ꢁC for 3h. After cooling to room
temperature, the mixture was evaporated under reduced pressure.
The crude product was purified by column chromatography on
silica (hexane/CH2Cl2 = 6:1) to yield 4 as a green solid (1.23 g, 30%).
NMR (400 MHz, CDCl3,
d
): 9.96 (s, 1H), 8.07e8.09 (d, J¼8.4 Hz, 1H),
7.84e7.85 (d, J¼4 Hz, 1H), 7.78e7.81 (m, 2H), 7.59e7.61 (d, J¼7.2 Hz,
1H), 7.51e7.55 (m, 1H), 7.46e7.49 (m, 3H), 7.25e7.42 (m, 24H),
7.08e7.12 (m, 4H), 6.89e6.93 (t, J¼7.6 Hz, 2H). 13C NMR (100 MHz,
1H NMR (400 MHz, CDCl3,
(m, 2H), 7.64e7.66 (d, J¼7.6 Hz, 1H), 7.45e7.53 (m, 4H), 7.35e7.40
(m, 15H), 7.28e7.31 (m, 8H), 7.09e7.12 (t, J¼6.8 Hz, 4H), 6.88e6.90
d): 7.91e7.93 (d, J¼8.4 Hz, 1H), 7.76e7.79
CDCl3, d): 182.89, 151.95, 147.77, 147.74, 147.70, 143.58, 138.36,
137.39, 136.84, 136.04, 135.41, 135.07, 134.92, 134.19, 133.44, 133.25,

T. Wang et al. / Tetrahedron 68 (2012) 10372e10377
10377
132.17, 132.06, 130.79, 129.91, 129.83, 129.48, 129.03, 128.39, 127.89,
Supplementary data
127.05, 127.00, 126.19, 126.07, 124.78, 124.75, 124.50, 123.97, 123.89,
123.79, 123.30, 123.25, 122.75, 121.80. HRMS (m/z): [MþH]þ calcd
for C61H40N2OS: 849.2940, found: 849.2940.
Supplementary data associated with this article can be found in
the online version, at http://dx.doi.org/10.1016/j.tet.2012.09.013.
4.2.9. 3-(5-(7,12-Bis(4-(diphenylamino)phenyl)benzo[k]fluoranthen-
3-yl)thiophen-2-yl)-2-cyanoacrylic acid D2. The synthesis method
resembles compound D1, and the compound was purified by col-
umn chromatography on silica (CH2Cl2/CH3OH¼20:1) to yield D2 as
References and notes
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an orange solid (85%). 1H NMR (400 MHz, DMSO-d6,
d): 8.16 (s, 1H),
7.95e7.97 (d, J¼7.6 Hz, 1H), 7.77e7.78 (d, J¼3.6 Hz, 1H), 7.68e7.70
(d, J¼7.2 Hz, 1H), 7.61e7.62 (m, 2H), 7.34e7.51 (m, 14H), 7.12e7.27
(m, 18H), 6.76e6.78 (d, J¼7.6 Hz, 1H), 6.64e6.66 (d, J¼6.8 Hz, 1H).
13C NMR (100 MHz, THF-d8,
d): 147.50,147.43,147.39,147.33,146.48,
138.41, 137.86, 137.77, 136.97, 134.36, 133.70, 132.92, 131.63, 130.21,
130.06, 130.02, 129.75, 129.16,129.13,129.08, 128.95,128.90,128.82,
128.71, 126.34, 126.24, 125.40, 124.31, 124.27, 123.92, 123.79, 123.45,
123.23, 123.14, 123.02, 122.76, 122.70, 118.67, 113.18, 112.43. HRMS
(m/z): [MþH]þ calcd for C64H41N3O2S: 916.2998, found: 916.2996.
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yl)benzaldehyde (7). A stirred mixture of 4 (0.41 g, 0.50 mmol), 4-
formylphenylboronic acid (0.075 g, 0.50 mmol), Pd(PPh3)4
(0.0075 g, 0.0065 mmol), Na2CO3 (65 mg, 0.6 mmol), THF(10 mL),
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evaporated under reduced pressure. The crude product was puri-
fied by column chromatography on silica (hexane/CH2Cl2¼1:1) to
yield 6 as an orange solid (0.30 g, 71%). 1H NMR (400 MHz, CDCl3,
ꢀ
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d
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7.73e7.75 (d, J¼8.4 Hz, 2H), 7.46e7.50 (m, 3H), 7.41e7.44 (m, 5H),
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2H), 7.69e7.71(m, 2H), 7.63e7.65 (d, J¼7.2 Hz, 1H), 7.55e7.58 (m,
3H), 7.41e7.44 (m, 11H), 7.25e7.30 (m, 12H), 7.11e7.15 (m, 4H). 13C
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NMR (100 MHz, DMSO-d6, d): 147.31, 147.22, 147.09, 143.06, 143.01,
137.38, 136.21, 136.03, 135.04, 134.52, 134.45, 134.09, 133.58, 132.54,
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found: 910.3431.