Application of indoline dyes attached with strongly electron-withdrawing carboxylated indan-1,3-dione analogues linked with a hexylthiophene ring to dye-sensitized solar cells

Article abstract of DOI:10.1016/j.tet.2018.04.077

An indoline dye attached with a carboxylated indan-1,3-dione moiety linked with a hexylthiophene ring exhibited the highest conversion efficiency among six analogues and D205. This result comes from the bathochromic UV–vis absorption band, suitable energy

Full text of DOI:10.1016/j.tet.2018.04.077

Accepted Manuscript
Application of indoline dyes attached with strongly electron-withdrawing carboxylated
indan-1,3-dione analogues linked with a hexylthiophene ring to dye-sensitized solar
cells
Masaki Matsui, Nagisa Tanaka, Kazumasa Funabiki, Yuki Haishima, Kazuhiro
Manseki, Jiye Jin, Yukiko Inoue, Shinji Higashijima, Yasuhiro Kubota
PII:
S0040-4020(18)30482-4
10.1016/j.tet.2018.04.077
TET 29492
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 18 February 2018
Revised Date: 21 April 2018
Accepted Date: 24 April 2018
Please cite this article as: Matsui M, Tanaka N, Funabiki K, Haishima Y, Manseki K, Jin J, Inoue Y,
Higashijima S, Kubota Y, Application of indoline dyes attached with strongly electron-withdrawing
carboxylated indan-1,3-dione analogues linked with a hexylthiophene ring to dye-sensitized solar cells,
Tetrahedron (2018), doi: 10.1016/j.tet.2018.04.077.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to
our customers we are providing this early version of the manuscript. The manuscript will undergo
copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please
note that during the production process errors may be discovered which could affect the content, and all
legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT
20
10
0
C6H13
3a
3b
X
S
3c
Y
COOH
N
3d
3e
3f
H3C
D205
H3C
Y
X
Dye
0
200
400
600
800
C=O
C=O
C=C(CN)2
C=O
C=OC
C=C(CN)2
Photovoltage / mV
S
SO2
3c SO2
3d C=O
3a
3b
The best performance was obtained for 3d due
to suitable energy levels and sufficiently long
singlet excited lifetime compared with the
other derivatives.
3e C=C(CN)2
3f
C=C(CN)2

ACCEPTED MANUSCRIPT
Application of indoline dyes attached with strongly electron-withdrawing
carboxylated indan-1,3-dione analogues linked with a hexylthiophene ring to
dye-sensitized solar cells
Masaki Matsui,a,* Nagisa Tanaka,a Kazumasa Funabiki,a Yuki Haishima,a Kazuhiro Manseki,a Jiye Jin,b
Yukiko Inouec Shinji Higashijimac and Yasuhiro Kubota,a
a Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University,
1-1 Yanagido, Gifu 501-1193, Japan. E-mail: matsuim@gifu-u.ac.jp
b Department of Chemistry, Faculty of Science, Shinshu University,
3-1-1-Asahi, Matsumoto, Nagano 390-8621, Japan
c Chemicrea Inc., Ohtsurugi Shimogawa, Izumi-machi, Iwaki, Fukushima 971-8183, Japan
Keywords: Dye-sensitized solar cells; Sensitizers; Indoline dyes; indan-1,3-dione analogues;
Electron-withdrawing moieties.
Abstract
An indoline dye attached with a carboxylated indan-1,3-dione moiety linked with a hexylthiophene ring
exhibited the highest conversion efficiency among six analogues and D205. This result comes from the
bathochromic UV-vis absorption band, suitable energy levels, good stability for redox process, and
sufficiently long excited-state lifetime.
1. Introduction
Indoline dyes are one of the most efficient organic sensitizers in dye-sensitized solar cells (DSSCs).1
Therefore, much effort has been devoted to obtain bathochromic indoline dyes by changing the pull
moiety. Indoline dyes attached with cyanoacrylic acid,2 single,3 double,4 and triple rhodanine acetic acid5
pull moiety have been prepared and evaluated as the sensitizers. The first absorption maximum (λmax) of
triple rhodanine indoline dye was observed at 572 nm in chloroform.5 Those of double rhodanine indoline
dyes linked with mono-, di-, and trithienyl spacers were observed at 568, 564, and 550 nm, respectively.6
1

ACCEPTED MANUSCRIPT
Thus, these indoline dyes are not bathochromic as expected. In 2012, carboxylated indan-1,3-dione was
used as an electron acceptor anchor moiety in DSSCs.7 Recently, an indoline dye attached with a
5-carboxyindan-1,3-dione pull anchor moiety linked with a thienyl ring has been reported to exhibit the
λmax at around 600 nm in chloroform and to show higher conversion efficiency than D205.8 We consider
that the indoline dyes having more electron-withdrawing pull moiety can show more bathochromic
absorption bands to exhibit higher conversion efficiency. We report here the synthesis and
photoelectrochemical properties of novel indoline dyes with a carboxylated benzo[b]thiophene-3(2H)one,
benzo[b]thiophene-3(2H)one 1,1-dioxide, benzo[b]thiophene-3(2H)dicyanovinilidene 1,1-dioxide,
indan-1,3-dione, indan-1-dicyanovinilidene-3-one, and indan-1,3-bis(dicyanovinilidene) anchor pull
moiety linked with a hexylthiophene ring in DSSCs.
2. Results and Discussion
2.1.Synthesis
Novel indoline dyes 3a, 3b, 3c, 3d, 3e and 3f were synthesized as shown in Scheme 1. Compound
2a was obtained by the intramolecular Friedel–Crafts alkanoyl reaction of A.9 Compound 2b was
provided by the oxidation of 2a. Compound B, prepared by the reaction of 4-mercaptobenzoic acid
with ethanol in the presence of concentrated sulfuric acid, was allowed to react with chloroacetic acid
to afford a carboxymethylthio derivative C, followed by the intramolecular Friedel–Crafts alkanoyl
reaction to yield a sulfide D. Compound D was oxidized to provide a sulfone E, which was allowed to
react with malononitrile followed by the hydrolysis of the ester moiety to give a dicyanovinilidene
derivative 2c. Compound G was allowed to react with ethyl acetoacetate to give a compound H,
which was reacted with 3.0 molar amounts of malononitrile to provide both the
mono(dicyanovinilidene) I and I’ (51 %) and bis(dicyanovinilidene) derivatives J (28 %). The mono
and bis derivatives were separated by column chromatography. For the mono derivative, both the 6-
and 5-ethoxycarbonyl regio isomers I and I’ were formed. These isomers were not separated by
chromatography due to the same Rf value (SiO2 TLC, Rf = 0.35, CHCl3 : MeOH = 3 : 1). However,
when the mixture was recrystallized from ethanol, only the 6-ethoxycarbonyl isomer I was obtained
as a crystalline form in a 28 % yield.
The heteronuclear multiple bond coherence (HMBC) spectrum of I is shown in Figure 1. The spectrum
indicates that the H5 peak correlates with the C7, C5, and COO peaks. The H7 peak correlates with the
C5, C3a, and COO peaks. The H4 peak correlates with the C6, C7a, and C3 peaks. Thus, compound I was
2

ACCEPTED MANUSCRIPT
identified as ethyl indan-3-dicyanovinilidene-1-one-6-carboxylate. The hydrolysis of ester moiety of I
afforded the carboxyl derivative 2e. Compound H was allowed to react with 4.0 molar amounts of
malononitrile to give J in a 78 % yield. The hydrolysis of the ester moiety of J provided a carboxylic acid
2f. Finally, an indoline carboaldehyde 1 was allowed to react with 2a, 2b, 2c, 2d, 2e, and 2f to afford 3a,
3b, 3c, 3d, 3e, and 3f, respectively.
Figure 1. HMBC spectrum of I.
3

ACCEPTED MANUSCRIPT
Scheme 1.
Reagents and conditions: i) A (1.0 molar amount), SOCl2 (excess), AlCl3 (4.0 molar
amounts), CH2ClCH2Cl, 0 °C, 20 min then rt, 18 h, ii) 2a (1.0 molar amount), oxone (2.0
molar amounts), 1,4-dioxane-water (5/1), rt, 3 h, iii) CH2ClCOOH (1.5 molar amounts),
K2CO3 (2.0 molar amounts), MeCN, rt, 3 h, then B (1.0 molar amount), 60 °C, 3 h, iv) C (1.0
molar amount), SOCl2 (5 molar amounts), reflux, 30 min, then, AlCl3 (4.0 molar amounts),
CH2ClCH2Cl, 0 °C, 30 min, then rt, 21 h, v) D (1.0 molar amount), oxone (2.0 molar
amounts), 1,4-dioxane-water (5/1), rt, 23 h, vi) E (1.0 molar amount), CH2(CN)2 (2.5 molar
amounts), AcONa (1.0 molar amount), EtOH, reflux, 17 h, vii) F (1.0 molar amount),
Me3SiOK (1.0 molar amount), THF, rt, 21 h, then 10 % HCl, viii) G (1.0 molar amount),
AcCH2COOEt (1.0 molar amount), Et3N, (6.0 molar amounts), Ac2O, 70 °C, 30 min, ix) H
(1.0 molar amount), CH2(CN)2 (3.0 molar amounts), AcONa (1.0 molar amount), EtOH,
reflux, 1 h, x) I (1.0 molar amount), Me3SiOK (3.0 molar amounts), rt, 24 h, xi) H (1.0 molar
amount), CH2(CN)2 (4.0 molar amounts), AcONa (1.0 molar amount), EtOH, reflux, 17 h, xii)
J (1.0 molar amount), H2O (excess), LiOH (7.0 molar amounts), THF, rt, 24 h, xiii) 1 (1.0
molar amount), 2a, 2b, 2c (1.3 molar amounts), AcOH, AcONH4 (cat.), 120 °C. 2‒4 h, or 1
(1.0 molar amount), 2d, 2e, 2f (1.0 molar amount), AcOH, 55‒100 °C, 3‒4 h.
4

ACCEPTED MANUSCRIPT
2.2.UV-Vis absorption and fluorescence spectra
The UV-Vis absorption and fluorescence spectra of 3a, 3b, 3c, 3d, 3e, and 3f in chloroform are shown
in Figure 2 and the results are summarized in Table 1. The λmax was more bathochromic in the order of
dyes: 3f (821 nm) > 3c (750 nm) > 3e (709 nm) > 3b (614 nm), 3d (610 nm) > 3a (561 nm). The molar
absorption coefficients (ε
) were observed in the range of 39,000 to 65,800 dm3 mol-1 cm-1. Dyes 3a, 3b,
and 3d were fluorescent, showing the fluorescence maximum (Fmax) at 713, 742, and 731 nm with
fluorescence quantum yield (Φf) of 0.06, 0.10, and 0.21, respectively. Dyes 3c and 3e were very weak
fluorescent compounds, having Φf lower than 0.01. Dye 3f was non-fluorescent.
0.8
3a
3b
3c
200
0.6
3d
3e
3f
3a
0.4
3b
3d
100
0.2
0
0
400
600
800
1000
Wavelength / nm
Figure 2.
UV-Vis absorption and fluorescence spectra of 3a, 3b, 3c, 3d, 3e, and 3f (1.0 × 10‒5 mol
dm‒3) in chloroform. Solid and dotted lines represent the UV-Vis and fluorescence spectra,
respectively.
5

ACCEPTED MANUSCRIPT
Physical data of 3a, 3b, 3c, 3d, 3e, and 3f
Table 1
)a / nm
Φfa
τfa / ns
Dye
Fmaxa / nm
Eoxb / V Eredb / V
λmax
(
ε
370 (25,300), 561 (39,000)
371 (21,100), 412 (sh), 614 (48,800)
371 (sh), 471 (11,000), 750 (64,600)
713
742
901
0.06
0.10
< 0.01
0.70
0.66
0.87
0.98
0.99
–1.05
–0.83
–0.24
3a
3b
3c
c
-
371 (25,300), 412 (sh), 610 (53,500)
366 (25,000), 709 (65,800)
731
819
0.21
1.29
1.22
0.97
–0.60
–0.73
–0.17d
3d
3e
c
< 0.01
-
c
c
c
375 (sh), 821 (44,800)
-
-
-
0.97
3f
a Measured on 1.0 × 10‒5 mol dm‒3 of substrate in chloroform.
b vs. NHE in DMF.
c Not measured.
d Calculated on the basis of Eox and onset peak.
The fluorescence decay curves of 3a, 3b, and 3d are indicated in Figure 3. The fluorescence lifetime
τf) was determined by fitting the curve with a one-component exponential function. The τf of 3a, 3b, and
(
3d were observed to be 0.70, 0.66, and 1.29 ns, respectively. The fluorescence of 3c and 3e was too weak
to measure τf
.
Figure 3.
Fluorescence decay curve of 3a, 3b, and 3d (1.0 × 10‒5 mol dm‒3) in chloroform.
2.3.Electrochemical measurements
Figure 4 shows the cyclic voltammogram of 3a, 3b, 3c, 3d, 3e, and 3f vs. Ag quasi reference
electrode (QRE) in DMF in the presence of ferrocene (Fc). In Figure 4b, the oxidation potential (Eox) of
Fc and 3d and the reduction potential (Ered) of 3d were observed at +0.99, +1.58, and ‒0.24 V,
6

+
ACCEPTED MANUSCRIPT
respectively. Then, the Eox and Ered of 3d were calculated to be +0.59 and ‒1.23 V vs. Fc/Fc ,
respectively. Therefore, the Eox and Ered of 3d were calculated to be +1.22 and ‒0.60 V vs. NHE,
respectively.10 In a similar way, the Eox and Ered levels of 3a, 3b, 3c, and 3e were obtained. As the
reduction peak of 3f was not observed by the electrochemical measurements, the Ered level was calculated
on the basis of the onset peak of the UV-Vis absorption band. The Eox and Ered of 3a, 3b, 3c, 3d, 3e, and
3f are also listed in Table 1.
1
0
1
0
3a
3b
3c
3d
3e
3f
-1
-2
-1
-2
2
1
0
-1
-2
2
1
0
-1
-2
Potential / V vs. Ag
Potential / V vs. Ag
Figure 4. Cyclic voltammogram of (a) 3a, 3b, and 3c, and (b) 3d, 3e, and 3f measured vs. Ag quasi
reference electrode in DMF in the presence of ferrocene (scan rate: 50 mV sec‒1).
2.4.DFT calculations
The optimized structures of 3a, 3b, 3c, 3d, 3e, and 3f by the DFT calculations (B3LYP/3-21G level)
are shown in Figure S1. The E- and Z-configurations at the double bond between the hexylthiophene and
indan-1,3-dione ring analogue are considerable for the indoline dyes. Furthermore, s-trans and s-cis
conformations between the hexylthienyl ring and indan-1,3-dione analogue moiety are considerable for
the respective E- and Z-configurations. Thus, four stereo isomers are considerable. Consequently, the E-
and s-trans form was calculated to be most stable for 3d. For the other derivatives, the stereo isomer
having the least electronic repulsion between the hexylthienyl moiety and the substituent at the 1- or
3-position in the indan-1,3-dione analogue was most stable.
The single-point energy calculations were performed for the optimized structures by the
B3LYP/6-31G(d,p) level. The calculated absorption maximum, main orbital transition, and oscillator
strength of 3a, 3b, 3c, 3d, 3e, and 3f are shown in Table 2. The HOMO to LUMO transition was the main
7

ACCEPTED MANUSCRIPT
contribution (62–71 %) for the first absorption band, indicating that the HOMO and LUMO levels are
important for the indoline dyes.
Table 2 Absorption maxima (λmax), main orbital transition, and oscillator strengths (f) of 3a, 3b, 3c, 3d,
3e, and 3f calculated by TDDFT at the B3LYP/6-31G(d,p)//B3LYP/3-21G level
λmaxa / nm
548
Dye
Transition
Main orbital transition
HOMO to LUMO (0.70)
f
S0 to S1
S0 to S2
1.03
0.26
3a
424
HOMO‒1 to LUMO (0.66), HOMO‒2 to LUMO (0.13),
HOMO to LUMO+2 (0.17)
S0 to S1
S0 to S2
S0 to S1
S0 to S2
S0 to S3
S0 to S1
S0 to S2
S0 to S1
S0 to S2
S0 to S3
S0 to S1
S0 to S2
S0 to S3
491
451
673
498
479
567
489
623
568
451
700
643
507
HOMO to LUMO (0.70)
HOMO to LUMO+1 (0.70)
0.92
0.18
0.98
0.30
0.22
0.94
0.20
1.00
0.27
0.27
0.35
0.74
0.07
3b
3c
HOMO to LUMO (0.70)
HOMO to LUMO+1 (0.69)
HOMO‒1 to LUMO+1 (0.69), HOMO to LUMO+2 (0.10)
HOMO to LUMO (0.71)
3d
3e
HOMO to LUMO+1 (0.69)
HOMO to LUMO (0.69)
HOMO to LUMO+1 (0.69)
HOMO‒1 to LUMO (0.69), HOMO to LUMO+2 (0.11)
HOMO to LUMO (0.62), HOMO to LUMO+1 (0.33)
HOMO to LUMO+1 (0.62)
3f
HOMO‒1 to LUMO (0.69)
Figure 5 shows the surface isodensity plots of HOMO–1, HOMO, LUMO, and LUMO+1 together
with the energy levels in 3a, 3b, 3c, 3d, 3e, and 3f. These dyes showed intramolecular charge-transfer
from the indoline to carboxylated indan-1,3-dione analogues in the first absorption band. The HOMO
levels of 3a, 3b, 3c, 3d, 3e, and 3f were calculated to be 0.87, 0.98, 0.99, 1.22, 0.97, and 0.97,
respectively. That of D205 has been reported to be –5.06 eV.4b Thus, the Eox levels are low enough to
‒
accept electrons from I‒/I3 electrolyte.
The LUMO levels of 3a, 3b, 3c, 3d, 3e, and 3f were calculated to be –2.37, –2.77, –3.20, –2.53, –
2.93, and –3.27, respectively. That of D205 has been reported to be –2.36 eV.4b The DFT calculations
predict that the LUMO levels of 3c and 3f are low compared with the other analogues.
8

ACCEPTED MANUSCRIPT
Figure 5.
Surface isodensity plots and energy levels of 3a, 3b, 3c, 3d, 3e, and 3f.
2.5.Photoelectrochemical properties
The UV-Vis absorption spectra on titanium dioxide, IPCE spectra, and I-V curve of 3a, 3b, 3c, 3d, 3e,
and 3f are shown in Figure 6, and the results are summarized in Table 3. Figure 6a shows that the UV-Vis
absorption bands are broad compared with those in chloroform due to the aggregate formation on titanium
dioxide. Figure 6b indicates that the maximum IPCE value of 3d was higher than 70 % in the range of
500 to 650 nm, resulting in the highest short-circuit photocurrent (Jsc) among them. The I-V curve is
shown in Figure 6c. Dye 3d exhibited the Jsc and open-circuit photovoltage (Voc) of 14.9 mA cm‒2 and
0.621 V, respectively. The Jsc value was significantly higher than that of D205. Thus, dye 3d showed the
highest conversion efficiency of 5.55 % among 3a, 3b, 3c, 3d, 3e, 3f, and D205.
9

ACCEPTED MANUSCRIPT
4
3
2
1
1
3a
3b
3c
3a
3d
3b
0.8
3e
3c
3f
D205
3d
0.6
0.4
0.2
0
3e
3f
D205
0
400
500
600
700
800
400 500 600 700 800 900
20
10
3a
3b
3c
3d
3e
3f
D205
0
0
200
400
600
800
Figure 6.
(a) UV-Vis absorption spectra on titanium dioxide, (b) IPCE spectra, and (c) I-V
curve of 3a, 3b, 3c, 3d, 3e, 3f, and D205.
Table 3 Photoelectrochemical properties of 3a, 3b, 3c, 3d, 3e, 3f, and D205
Dye
3a
Jsc / mA cm‒2 Voc / V
ff
η
/ %
7.63
5.16
0.68
14.9
1.15
0.11
9.85
0.523
0.566
0.381
0.621
0.433
0.291
0.630
0.57
0.71
0.70
0.60
0.67
0.54
0.69
2.29
2.06
0.18
5.55
0.33
0.02
4.33
3b
3c
3d
3e
3f
D205
The UV-Vis absorption band, energy levels, and excited-state lifetime drastically change by the
kinds of indane-1,3-dione analogue moiety. As the indoline dyes have the intramolecular push–pull
chromophoric system, the stronger the electron-withdrawing ability of the indan-1,3-dione
10

ACCEPTED MANUSCRIPT
analogues, the more bathochromic the λmax. As expected, the λmax on titanium dioxide was more
bathochromic in the order of dyes: 3f, 3c > 3e > 3b > 3d, 3a, which is in consistent with that in
chloroform. Comparing 3d and D205, the UV-Vis absorption edge of 3d and D205 on titanium
dioxide are observed at ca. 720 and 800 nm, respectively. The IPCE spectra clearly indicate that 3d
can act as a sensitizer in the range of 700 to 800 nm, which reflects higher Jsc value of 3d than that
of D205.
‒
The I‒/I3 redox level and conduction band (CB) level of titanium dioxide vs. NHE have been
reported to be ca. ‒0.5 and +0.4 V, respectively.11 The Eox levels of 3a, 3b, 3c, 3d, 3e, and 3f were
‒
lower than +0.4 V, indicating that the indoline dyes can accept electrons from I‒/I3 redox pair. The
Ered level of 3a (‒1.05 V vs. NHE), 3b (‒0.83 V vs. NHE), 3d (‒0.60 V vs. NHE), and 3e (‒0.73 V
vs. NHE) are higher than ‒0.5 V, suggesting that these dyes can inject electrons from the excited
state to the CB. Meanwhile, those of 3c (‒0.24 V vs. NHE) and 3f (‒0.17 V vs. NHE) were lower
than the CB level. Thus, both the electrochemical measurements and DFT calculations indicated
that dyes 3c and 3f could not thermodynamically sensitize titanium dioxide.
Organic sensitizers should have long excited-state lifetime to inject electrons from the excited
state to the CB of semiconductors. The τf of 3a, 3b, and 3d in chloroform were observed to be 0.70,
0.66, and 1.29 ns, respectively. We have proposed that the τf value for the efficient indoline dye
should be larger than ca. 0.8 ns.12 Thus, the τf measurements suggest that dye 3d can act as a highly
efficient indoline sensitizer.
The color of 3c and 3e adsorbed on titanium dioxide changed from green and blue to yellow
during I-V measurements, indicating that these dyes are not stable enough for electrochemical redox
process.
Consequently, dye 3d exhibited the highest conversion efficiency among the analogues and
D205. It should be noted that such an improved performance of 3d can be explained by the
bathochromic UV-Vis absorption band, suitable energy levels, and a sufficiently long excited-state
lifetime that allows for favored charge separation.
11

ACCEPTED MANUSCRIPT
3. Conclusions
Six kinds of indoline dyes having a carboxylated indan-1,3-dione analogues linked with
a hexylthiophene ring were synthesized and evaluated as the sensitizers. The indoline dye
having the indan-1,3-dione exhibited the highest conversion efficiency of 5.55 % in DSSC
among the analogues and D205. This result originates from the bathochromic UV-Vis
absorption band, suitable energy levels, good stability for redox process, and sufficiently
long lifetime in the excited state.
4. Experimental section
4.1.General
Melting points were measured with a Yanagimoto MP-S2 micro-melting-point apparatus. IR
spectra were taken on a Shimadzu Affinity-1 spectrophotometer. NMR spectra were taken with a
JEOL JNM-ECX 400P spectrometer. Mass spectra were taken on a JEOL MStation 700
spectrometer. Elemental analysis was performed with a Yanaco MT-6 CHN analyzer. UV-Vis
absorption and fluorescence spectra were taken on Hitachi U-4100 and JASCO FP-8600
spectrophotometers, respectively. Fluorescence quantum yields and fluorescence lifetime were
measured by Hamamatsu Photonics Quantaurus-QY and Quantaurus-Tau instruments, respectively.
Electrochemical measurement was carried out using an EG&G Princeton Applied Research
Potentiostat/Galvanostat (Model 263A) driven by the M270 software package.
4.2.Materials
12

ACCEPTED MANUSCRIPT
Compound B was prepared by the reaction of 4-mercaptobenzoic acid with ethanol in the
presence of conc. sulfuric acid. Compounds G was prepared as described in literature.13 Compounds
1 and 2d were supplied from Chemicrea Inc.
4.3.Synthesis of 2b
To a 1,4-dioxane-water (5 : 1) mixed suspension (24 mL) of 2a (650 mg, 3.3 mmol) was added
oxone (4.0 g, 6.6 mmol). The suspension was stirred at room temperature for 3 h. After the reaction
was complete, the solid was filtered. The filtrate was concentrated in vacuo. The resulting
precipitate was recrystallized from ether. Yield 15 %; mp 230‒232 °C; IR (KBr)
ν = 3468, 1740,
1
1717, 1319, 1196 cm‒1; H NMR (DMSO-d6)
δ
= 4.68 (s, 2H), 8.28 (d, J = 8.3 Hz, 1H), 8.36 (s,
= 57.56, 122.25, 124.55, 133.57, 136.50,
13
1H), 8.52 (d, J = 8.3 Hz, 1H); C NMR (DMSO-d6)
δ
137.58, 149.81, 165.28, 187.16; EIMS (70 eV) m/z (rel intensity) 226 (M+, 70), 162 (100); Anal.
Calcd for C9H6O5S: C, 47.79; H, 2.67. Found: 47.57; H, 2.72.
4.4.Synthesis of C
To an acetonitrile solution (55 mL) of chloroacetic acid (4.3 g, 45 mmol) was added potassium
carbonate (8.3 g, 60 mmol). The mixture was stirred at room temperature for 10 min. Then, to the
mixture was added B (5.5 g, 30 mmol) and stirred at 60 °C for 3 h. After the reaction was complete,
to the mixture was added dichloromethane (150 mL) and water (100 mL). Water layer was acidified
with 10 % hydrochloric acid. The resulting precipitate was filtered and purified by column
chromatography (SiO2, CH2Cl2) to give white powder. Yield 88 %; mp 117‒119 °C; IR (KBr)
1705 cm‒1 ; 1H NMR (DMSO-d6)
ν =
δ
= 1.31 (t, J = 7.1 Hz, 3H), 3. (s, 2H95), 4.29 (q, J = 7.1 Hz, 2H),
13
7.41 (d, J = 8.7 Hz, 2H), 7.86 (d, J = 8.7 Hz, 2H); C NMR (DMSO-d6)
δ = 14.17, 39.08, 60.66,
13

ACCEPTED MANUSCRIPT
126.04 (2C), 126.52, 129.54 (2C), 143.08, 165.36, 170.18; EIMS (70 eV) m/z (rel intensity) 240
(M+, 100), 195 (93); Anal. Calcd for C11H12O4S: C, 54.99; H, 5.03. Found: C, 54.68; H, 5.01.
4.5.Synthesis of D
To thionylchloride (5 mL) was added C (1.0 g, 4.2 mmol) and refluxed for 30 min. Then, the
excess thionylchloride was removed in vacuo. The product was dissolved in 1,2-dichroloethane (5
ml) and cooled to 0 °C. To the solution was added anhydrous aluminum (III) trichloride (2.2 g, 16.8
mmol). The mixture was stirred at 0 °C for 30 min and then at room temperature for 21 h. After the
reaction was complete, to the mixture was added ice-water. The product was extracted with
dichloromethane (50 mL × 3). The organic layer was dried over anhydrous sodium sulfate,
concentrated, and purified by column chromatography (SiO2, CH2Cl2). Yield 81 %; mp 66‒68 °C;
IR (KBr)
ν δ = 1.40 (t, J = 7.1 Hz, 3H), 3.87 (s, 2H), 4.39 (q,
= 1717, 1686 cm‒1; 1H NMR (CDCl3)
J = 7.1 Hz, 2H), 7.49 (d, J = 8.4 Hz, 1H), 8.21 (dd, J = 8.4 and 1.8 Hz, 1H), 8.42 (d, J = 1.8 Hz,
13
1H); C NMR (CDCl3)
δ = 14.27, 39.85, 61.36, 124.44, 127.51, 127.95, 130.98, 136.14, 159.27,
165.37, 198.96; EIMS (70eV) m/z (rel intensity) 222 (M+, 80), 177 (100); Anal. Calcd for
C11H10O3S: C, 59.44; H, 4.53. Found; C, 59.29; H, 4.38.
4.6.Synthesis of E
To a 1,4-dioxane-water (5 : 1) mixed suspension of D (752 mg, 3.4 mmol) was added oxone
(4.2 g, 6.8 mmol). The suspension was stirred at room temperature for 23 h. After the reaction was
complete, the solid was filtered. The filtrate was concentrated and purified by column
chromatography (SiO2, CHCl3) to give a pink powder. Yield 49 %; mp 142‒144 °C; IR (KBr)
1732, 1601, 1312, 1196 cm‒1; 1H NMR (CDCl3)
ν
=
δ
= 1.45 (t, J = 7.0 Hz, 3H), 4.17 (s, 2H), 4.47 (q, J
= 7.0 Hz, 2H), 8.07 (d, J = 8.2 Hz, 1H), 8.59 (d, J = 8.2 Hz, 1H), 8.65 (s, 1H); 13C NMR (CDCl3)
δ
14

ACCEPTED MANUSCRIPT
= 14.19, 57.57, 62.44, 122.01, 125.96, 133.38, 136.34, 137.90, 150.54, 163.77, 185.92; EIMS m/z
254 (M+, 59), 209(100); Anal. Calcd for C11H10O5S: C, 51.96; H, 3.96. Found: C, 51.75; H, 4.06.
4.7.Synthesis of F
To an ethanol suspension (4 mL) of E (200 mg, 0.79 mmol) were added malononitrile (130 mg,
2.0 mmol) and anhydrous sodium acetate (65 mg, 0.79 mmol). The mixture was refluxed for 17 h.
After the reaction was complete, to the mixture was added water (4 mL) and acidified by 10 %
hydrochloric acid. The product was extracted with dichloromethane (10 mL × 3), dried over
anhydrous sodium sulfate, and purified by column chromatography (SiO2, CH2Cl2) to give pink
1
powder. Yield 91 %; mp 166‒168 °C; IR (KBr)
(CDCl3)
8.56 (d, J = 8.2 Hz, 1H), 9.33 (s, 1H); C NMR (CDCl3)
ν
= 2230, 1717, 1327, 1165 cm‒1; H NMR
δ
= 1.45 (t, J = 7.2 Hz, 3H), 4.49 (q, J = 7.2 Hz, 2H), 4.61 (s, 2H), 8.04 (d, J = 8.2 Hz, 1H),
13
δ
= 14.07, 56.56, 62.76, 83.45, 110.99,
111.11, 123.08, 127.43, 129.58, 136.85, 137.27, 146.57, 156.73, 163.27; EIMS (70 eV) m/z (rel
intensity) 302 (M+, 30), 274 (92), 257 (100); Anal. Calcd for C14H10N2O4S: C, 55.62; H, 3.33; N,
9.27. Found: C, 55.11; H, 3.14; N, 8.98 %.
4.8.Synthesis of 2c
To a THF solution (25 mL) of F (300 mg, 1.0 mmol) was added potassium trimethylsilanolate
(255 mg, 2.0 mmol). The mixture was stirred at room temperature for 21 h. After the reaction was
complete, the mixture was concentrated and acidified with aqueous 10 % hydrochloric acid. The
product was extracted with dichloromethane (30 mL × 3), dried over anhydrous sodium sulfate, and
purified by column chromatography (SiO2, CH2Cl2 : MeOH = 25 : 1) to give pale pink powder.
1
Yield 48 %; mp 210‒212 °C; IR (KBr)
ν
= 3428, 2237, 1705, 1323, 1162 cm‒1; H NMR
13
(acetone-d6)
δ
= 5.00 (s, 2H), 8.23 (d, J = 7.9 Hz, 1H), 8.63 (d, J = 7.9 Hz, 1H), 9.35 (s, 1H); C
15

ACCEPTED MANUSCRIPT
= 57.37, 83.57, 112.66, 112.99, 123.79, 128.17, 131.15, 137.37, 137.98,
NMR (acetone-d6)
δ
148.02, 159.11, 165.23; EIMS (70 eV) m/z (rel intensity) 274 (M+, 100), 165 (51); Anal. Calcd for
C12H6N2O4S: C, 52.55; H, 2.21; N, 10.21. Found: 52.24; H, 2.52; N, 9.95.
4.9.Synthesis of H
To acetic anhydride (10 mL) were added G (1.5 g, 6.8 mmol), ethyl acetoacetate (889 mg, 6.8
mmol), and triethylamine (4.1 g, 40.8 mmol). The mixture was heated at 70 °C for 30 min. After the
reaction was complete, the mixture was poured into water (120 mL) containing conc. sulfuric acid
(12 mL). The resulting precipitate was filtered, dried, dissolved in acetonitrile, and refluxed for 1 h.
After cooling, the product was purified by column chromatography (SiO2, CHCl3 : MeOH = 100 :
1
1) to give an orange powder. Yield 71 %; mp 60‒62 °C; IR (KBr)
(CDCl3)
8.51 (d, J = 8.1 Hz, 1H), 8.63 (s, 1H); C NMR (CDCl3)
ν
= 1753, 1713 cm‒1; H NMR
δ
= 1.45 (t, J = 7.1 Hz, 3H), 3.33 (s, 2H), 4.46 (q, J = 7.1 Hz, 2H), 8.04 (d, J = 8.1 Hz, 1H),
13
δ
= 14.21, 45.41, 62.15, 123.30, 124.50,
136.38, 137.11, 143.33, 145.68, 164.63, 196.49, 196.74; FABMS (NBA) m/z 219 (MH+); Anal.
Calcd for C12H10O4: C, 66.05; H, 4.62. Found: C, 66.15; H, 4.68.
4.10. Synthesis of I
To an ethanol suspension (20 mL) of H (1.95 g, 8.9 mmol) were added malononitrile (1.77 g,
26.8 mmol) and anhydrous sodium acetate (689 mg, 8.9 mmol). The mixture was refluxed for 1 h.
After the reaction was complete, the reaction mixture was poured into water (50 mL). The solution
was acidified with 10 % aqueous hydrochloric acid. The product was extracted with chloroform (50
mL × 3) and dried over anhydrous sodium sulfate. Red and blue spots were observed on silicagel
TLC. The red component (a mixture of I and I’, Rf = 0.35, CHCl3 : MeOH = 3 : 1) was isolated by
column chromatography (SiO2, CHCl3 : MeOH = 25 : 1) and recrystallized from ethanol to give I as
16

ACCEPTED MANUSCRIPT
1
a pale yellow solid. Yield 28 %; mp 190‒192 °C; IR (KBr)
(CDCl3) = 1.45 (t, J = 7.0 Hz, 3H), 3.81 (s, 2H), 4.47 (q, J = 7.0 Hz, 2H), 8.53 (d, J = 8.5 Hz, 1H),
8.58 (s, 1H), 8.72 (d, J = 8.5 Hz, 1H); C NMR (CDCl3)
ν
= 2234, 1734, 1717 cm‒1; H NMR
δ
13
δ
= 14.19, 43.46, 62.35, 80.98, 111.70,
111.79, 125.63, 125.99, 136.62, 136.84, 140.61, 145.08, 164.09, 165.03, 193.97; FABMS (NBA)
m/z 267 (MH+); Anal. Found: C, 67.58; H, 3.61; N, 10.48 %. Calcd for C15H10N2O3: C, 67.67; H,
3.79; N, 10.5 2%. The blue component (Rf = 0.50, CHCl3 : MeOH = 3 : 1) was isolated by column
chromatography (SiO2, CHCl3 : MeOH = 25 : 1) to give J (28 %) as a blue solid.
4.11. Synthesis of 2e
To a THF solution (20 mL) of I (500 mg, 1.9 mmol) was added potassium trimethylsilanolate
(723 mg, 5.6 mmol). The mixture was stirred at room temperature for 24 h. After the reaction was
complete, the mixture was acidified with 10 % aqueous hydrochloric acid. The product was
extracted with chloroform (50 mL × 4), dried over anhydrous sodium sulfate, and purified by
column chromatography (SiO2, CH2Cl2 : MeOH = 20 : 1) to give orange powder. Yield 99 %; mp
239‒241°C; IR (KBr)
ν
= 1717 cm‒1; 1H NMR (acetone-d6)
δ
= 4.00 (s, 2H), 8.44 (s, 1H), 8.61 (d, J
= 44.42, 80.67, 113.08, 113.29,
13
= 8.3 Hz, 1H), 8.72 (d, J = 8.3 Hz, 1H); C NMR (acetone-d6)
δ
125.39, 126.66, 137.09, 137.28, 141.97, 146.44, 165.71, 167.80, 195.58; FABMS (NBA) m/z 239
(MH+); Anal. Calcd for C13H6N2O3: C, 65.55; H, 2.54; N, 11.76. Found: C, 65.37; H, 2.46; N,
11.58.
4.12. Synthesis of J
To an ethanol suspension (10 mL) of H (800 mg, 3.7 mmol) were added malononitrile (975 mg,
14.6 mmol) and anhydrous sodium acetate (283 mg, 3.7 mmol). The mixture was refluxed for 17 h.
After the reaction was complete, the mixture was poured into water (50 mL) and acidified with 10%
17

ACCEPTED MANUSCRIPT
aqueous hydrochloric acid. The product was extracted with chloroform (70 mL × 3), dried over
anhydrous sodium sulfate, and purified by column chromatography (SiO2, CHCl3 : MeOH = 25 : 1)
1
to give blue precipitate. Yield 78%; mp 206‒208 °C; IR (KBr)
(acetone-d6)
1H), 8.71 (d, J = 8.2 Hz, 1H), 9.20 (s, 1H); C NMR (acetone-d6)
ν
= 2226, 1719 cm‒1; H NMR
δ
= 1.42 (t, J = 7.1 Hz, 3H), 4.47 (q, J = 7.1 Hz, 2H), 4.69 (s, 2H), 8.61 (d, J = 8.2 Hz,
13
δ
= 14.34, 43.16, 62.90, 79.69,
80.60, 112.76, 112.82, 112.98 (2C), 127.40, 127.56, 136.83, 137.41, 141.96, 144.61, 164.61,
167.25, 167.57; FABMS (NBA) m/z 315 (MH+); Anal. Calcd for C11H12O4S: C, 68.79; H, 3.21; N,
17.8. Found: C, 69.06; H, 3.33, N, 17.52.
4.13. Synthesis of 2f
To a THF solution (2 mL) of J (100 mg, 0.32 mmol) were added water (1 mL) and lithium
hydroxide (54 mg, 2.24 mmol). The mixture was stirred at room temperature for 24 h. After the
reaction was complete, the mixture was concentrated and acidified with 10 % hydrochloric acid.
The product was extracted with dichloromethane (20 mL × 5), dried over anhydrous sodium sulfate,
and washed with hexane to give blue powder. Yield 98 %; mp >300 °C; IR (KBr)
1724 cm‒1; 1H NMR (acetone-d6)
, 9.24 (s, 1H); 13C NMR (acetone-d6)
ν = 3406, 2199,
δ
= 4.70 (s, 2H), 8.65 (d, J = 8.3 Hz, 1H), 8.73 (d, J = 8.3 Hz, 1H)
δ
= 43.19, 79.66, 80.59, 112.78, 112.83, 113.01 (2C), 127.39,
127.84, 137.16, 137.59, 141.98, 144.63, 165.41, 167.23, 167.57; FABMS (NBA) m/z 287 (MH+);
Anal. Calcd for C16H6N4O2: C, 67.14; H, 2.11; N, 19.57. Found: C, 66.95; H, 2.05; N, 19.49.
4.14. Synthesis of 3a
To an acetic acid solution (2 mL) of 2a (50 mg, 0.26 mmol) and 1 (140 mg, 0.26 mmol) was
added ammonium acetate (3 mg). The mixture was heated at 120 °C for 2 h. After the reaction was
complete, water was added to the mixture. The resulting precipitate was filtered and purified by
18

ACCEPTED MANUSCRIPT
column chromatography (SiO2, CHCl3 : MeOH = 100 : 1). Yield 35 %; mp 158‒160 °C; IR (KBr)
ν
1
= 3429, 1690 cm‒1; H NMR (DMSO-d6)
δ = 0.87 (t, J = 6.2 Hz, 3H), 1.27‒1.31 (m, 4H), 1.34–
1.38, (m, 2H), 1.42‒1.44 (m, 1H), 1.47 (s, 6H), 1.63‒1.67 (m, 3H), 1.78‒1.80 (m, 1H), 1.86‒1.92
(m, 2H), 2.07‒2.14 (m, 1H), 2.80 (t, J = 7.6 Hz, 2H), 3.87‒3.89 (m, 1H), 5.01‒5.04 (m, 1H), 6.99
(d, J = 8.2 Hz, 1H), 7.27‒7.34 (m, 3H), 7.48‒7.53 (m, 4H), 7.57 (s, 1H), 7.75 (d, J = 7.6 Hz, 1H),
7.81 (d, J = 7.6 Hz, 1H), 7.93 (d, J = 8.2 Hz, 1H), 8.09 (s, 1H), 8.17 (d, J = 8.2 Hz, 1H), 8.27 (s,
1H); 13C NMR (DMSO-d6)
δ = 13.96, 22.05, 24.09, 26.85, 26.98, 28.47, 28.51, 30.43, 31.02, 33.06,
34.80, 44.41, 46.55, 68.69, 79.17, 107.58, 114.19, 118.75, 119.45, 120.95, 122.21, 122.66, 122.96,
124.66, 124.79, 124.95, 125.95, 126.52, 126.62, 127.04, 128.58, 129.14, 130.94, 132.93, 135.10,
136.19, 138.45, 141.03, 148.07, 148.97, 151.32, 152.95, 153.09, 154.77, 166.37, 185.61; FABMS
(NBA) m/z 722 (MH+); Anal. Calcd for C46H43NO3S2: C, 76.53; H, 6.00; N, 1.94. Found: 76.20; H,
5.85; N, 1.92.
4.15.
Synthesis of 3b
To an acetic acid solution (2 mL) of 2b (50 mg, 0.22 mmol) and 1 (120 mg, 0.22 mmol) was
added ammonium acetate (3 mg). The mixture was heated at 120 °C for 2 h. After the reaction was
complete, water was added to the reaction mixture. The resulting precipitate was filtered and
purified by column chromatography (SiO2, CHCl3 : MeOH = 100 : 1). Yield 37 %; mp 175‒177 °C;
IR (KBr)
ν δ = 0.87 (t, J = 6.9 Hz, 3H), 1.28‒1.33
= 1728, 1377, 1157 cm‒1; 1H NMR (DMSO-d6)
(m, 4H), 1.36‒1.39 (m, 2H), 1.42‒1.47 (m, 1H), 1.47 (s, 3H), 1.48 (s, 3H), 1.66‒1.69 (m, 3H),
1.77‒1.79 (m, 1H), 1.84‒1.91 (m, 2H), 2.10‒2.15 (m, 1H), 2.91 (t, J = 7.6 Hz, 2H), 3.90‒3.92 (m,
1H), 5.09‒5.11 (m, 1H), 7.00 (d, J = 8.2 Hz, 1H), 7.29 (t, J = 7.2 Hz, 1H), 7.32‒7.35 (m, 2H), 7.54
(d, J = 7.5 Hz, 1H), 7.56 (d, J = 2.0 Hz, 1H), 7.61 (dd, J = 7.2 and 2.0 Hz, 1H), 7.67 (s, 1H), 7.69‒
7.71 (m, 1H), 7.78 (d, J = 7.5 Hz, 1H), 7.84 (d, J = 8.2 Hz, 1H), 8.14 (s, 1H), 8.29 (d, J = 8.3 Hz,
13
1H), 8.42 (s, 1H), 8.51 (d, J = 8.3 Hz, 1H); C NMR (DMSO-d6)
δ = 13.97, 22.05, 24.06, 26.81,
19

ACCEPTED MANUSCRIPT
26.97, 28.47, 28.81, 30.67, 30.97, 30.88, 35.00, 44.24, 46.62, 68.99, 79.19, 107.59, 114.96, 119.51,
119.62, 121.04, 121.44, 121.61, 122.08, 122.71, 123.01, 124.38, 125.19, 125.45, 126.72, 127.10,
127.55, 131.72, 132.42, 133.64, 136.51, 136.93, 138.35, 140.40, 146.11, 149.65, 153.21, 154.84,
158.99, 161.44, 165.43, 176.82; FABMS (NBA) m/z 754 (MH+); Anal. Calcd for C46H43NO5S2: C,
73.28; H, 5.75; N, 1.86. Found: 73.44; H, 5.52; N, 1.78.
4.16.
Synthesis of 3c
To an acetic acid solution (3 mL) of 2c (100 mg, 0.36 mmol) and 1 (200 mg, 0.36 mmol) was
added ammonium acetate (3 mg). The mixture was heated at 120 °C for 4 h. After the reaction was
complete, water was added to the reaction mixture. The resulting precipitate was filtered and
purified by column chromatography (SiO2, CHCl3 : MeOH = 100 : 1). Yield 28 %; mp 179‒181 °C;
1
IR (KBr)
ν
= 3433, 2210, 1732, 1396, 1177 cm‒1; H NMR (DMSO-d6)
δ
= 0.87 (m, 3H), 1.27‒
1.30 (m, 4H), 1.38‒1.44 (m, 3H), 1.47 (s, 3H), 1.48 (s, 3H), 1.66‒1.71 (m, 3H), 1.76‒1.78 (m, 1H),
1.84‒1.89 (m, 2H), 2.09‒2.15 (m, 1H), 2.90 (t, J = 7.9 Hz, 2H), 3.90‒3.93 (m, 1H), 5.13‒5.15 (m,
1H), 6.97 (d, J = 8.3 Hz, 1H), 7.29 (t, J = 7.2 Hz, 1H), 7.33‒7.35 (m, 2H), 7.54 (d, J = 7.5 Hz, 1H),
7.58 (s, 1H), 7.66 (d, J = 9.0 Hz, 1H), 7.71 (s, 1H), 7.76 (s, 1H), 7.79 (d, J = 7.5 Hz, 1H), 7.85 (d, J
13
= 8.3 Hz, 1H), 8.25 (d, J = 8.7 Hz, 1H), 8.44 (d, J = 8.7 Hz, 1H), 8.86 (s, 1H), 9.30 (s, 1H); C
NMR (DMSO-d6)
δ = 14.33, 22.40, 24.37, 27.15, 27.30, 29.10, 29.51, 31.36 (2C), 33.12, 35.39,
44.53, 47.02, 67.42, 69.72, 108.07, 115.91, 116.06, 116.47, 120.10, 120.41, 120.47, 121.45, 122.44,
122.62, 123.10, 123.83, 126.08 (2C), 127.23, 127.31, 127.49, 128.90, 129.68, 131.84, 134.60,
136.02, 136.88, 137.18, 138.63, 140.32, 141.27, 150.35, 150.99, 153.65, 155.27, 162.71, 163.44,
165.69; FABMS (NBA) m/z 802 (MH+); Anal. Calcd for C49H43N3O4S2: C, 73.38; H, 5.40; N, 5.24.
Found: 73.63; H, 5.53; N, 5.01.
4.17. Synthesis of 3d
20

ACCEPTED MANUSCRIPT
To an acetic acid solution (3 mL) of 1 (110 mg, 0.2 mmol) was added 2d (50 mg, 0.2 mmol).
The mixture was heated at 100 °C for 4 h. After the reaction was complete, the mixture was poured
into water (3 mL). The resulting precipitate was purified by column chromatography (SiO2, CHCl3 :
1
MeOH = 100 : 1). Yield 55 %; mp 152‒154 °C; IR (KBr)
(DMSO-d6)
ν
= 3429, 1724 cm‒1; H NMR
δ
= 0.85 (t, J = 6.5 Hz, 3H), 1.26‒1.29 (m, 4H), 1.32‒1.34 (m, 2H), 1.40‒1.43 (m, 1H),
1.47 (s, 3H), 1.48 (s, 3H), 1.61‒1.65 (m, 3H), 1.75‒1.77 (m, 1H), 1.83‒1.90 (m, 2H), 2.07‒2.13 (m,
1H), 2.80 (t, J = 7.2 Hz, 2H), 3.82‒3.85 (m, 1H), 5.00‒5.02 (m, 1H), 6.93 (dd, J = 8.2 and 6.2 Hz,
1H), 7.26‒7.29 (m, 2H), 7.32 (t, J = 7.6 Hz, 1H), 7.48 (s, 1H), 7.52‒7.53 (m, 3H), 7.57 (s, 1H), 7.74
(d, J = 6.8 Hz, 1H), 7.78‒7.80 (m, 2H), 7.84 (t, J = 7.6 Hz, 1H), 8.18 (d, J = 5.5 Hz, 1H), 8.27 (t, J
13
= 8.6 Hz, 1H); C NMR (DMSO-d6)
δ = 13.93, 22.05, 24.08, 26.83, 26.97, 28.61, 28.95, 30.60,
31.00, 32.97, 34.86, 44.33, 46.58, 68.88, 107.54, 114.58, 119.15, 119.51, 119.70, 120.94, 122.40,
122.65 (2C), 122.83, 125.00, 126.62, 127.06, 128.59, 131.52, 132.27, 133.36, 135.48, 136.24,
138.40, 139.49, 140.63, 141.20, 142.13, 143.81, 149.02, 153.16, 154.78, 157.45, 160.51, 166.15,
187.89, 189.05; FABMS (NBA) m/z 718 (MH+); Anal. Calcd for C47H43NO4S: C, 78.63; H, 6.04;
N, 1.95. Found: 78.66; H, 6.27; N, 1.92.
4.18. Synthesis of 3e
To an acetic anhydride solution (3 mL) of 1 (137 mg, 0.25 mmol) was added 2e (60 mg, 0.25
mmol). The mixture was stirred at 60 °C for 2 h. After the reaction was complete, the crude product
was concentrated and purified by column chromatography (SiO2, CHCl3 : MeOH = 100 : 1). Yield
1
20 %; mp 253‒255 °C; IR (KBr)
ν
= 3426, 2214, 1705 cm‒1; H NMR (DMSO-d6)
δ
= 0.87 (brs,
3H), 1.30 (brs, 4H), 1.38 (brs, 2H), 1.47 (s, 3H), 1.49 (s, 3H), 1.49 (brs, 1H), 1.67 (brs, 3H), 1.79
(brs, 1H), 1.87 (brs, 2H), 2.12 (brs, 1H), 2.88 (brs, 2H), 3.90 (brs, 1H), 5.13 (brs, 1H), 6.97 (d, J =
9.0 Hz, 1H), 7.29‒7.34 (m, 3H), 7.51‒7.58 (m, 2H), 7.66‒7.72 (m, 3H), 7.79 (d, J = 6.9 Hz, 1H),
21

ACCEPTED MANUSCRIPT
7.86 (d, J = 8.2 Hz, 1H), 8.17 (s, 1H), 8.36 (d, J = 7.9 Hz, 1H), 8.53 (d, J = 7.9 Hz, 1H), 8.75 (s,
1H); 13C NMR (DMSO-d6)
δ = 14.38, 22.47, 24.44, 27.22, 27.38, 29.13, 29.98, 31.23, 31.42, 33.24,
35.39, 44.64, 47.96, 69.60, 108.03, 115.71, 115.84, 116.21, 118.68, 120.10, 120.23, 1221.48,
122.87, 123.15 (2C), 123.33, 123.82, 124.74, 126.22, 127.22, 127.54, 128.59, 129.99, 131.96,
134.40, 135.89, 136.80, 137.03, 138.75, 140.57, 142.48, 142.95, 150.58, 153.67, 155.29, 161.95,
163.98, 166.23, 172.57, 187.50; FABMS (NBA) m/z 766 (MH+); Anal. Calcd for C50H43N3O3S: C,
78.40; H, 5.66; N, 5.49. Found: 78.10; H, 5.41; N, 5.22.
4.19. Synthesis of 3f
To an acetic anhydride solution (4 mL) of 1 (95 mg, 0.17 mmol) was added 2f (50 mg, 0.17
mmol). The mixture was stirred at 50 °C for 2 h, then at 55 °C for 1 h. After the reaction was
complete, to the mixture was added water (4 mL). The product was extracted with chloroform.
The extract was dried over anhydrous sodium sulfate, concentrated in vacuo, and purified by
column chromatography (SiO2, CHCl3 : MeOH = 100 : 1). Yield 39 %; mp 179‒181°C; IR (KBr)
= 3622, 2210, 1740 cm‒1; 1H NMR (CDCl3)
ν
δ
= 0.90 (t, J = 7.2 Hz, 3H), 1.33‒1.35 (m, 4H), 1.45‒
1.48 (m, 2H), 1.50 (s, 3H), 1.52 (s, 3H), 1.54‒1.61 (m, 1H), 1.74‒1.79 (m, 3H), 1.82‒1.87 (m, 1H),
1.96‒1.98 (m, 2H), 2.13‒2.17 (m, 1H), 2.89 (t, J = 7.9 Hz, 2H), 3.90‒3.93 (m, 1H), 5.05‒5.07 (m,
1H), 6.89 (d, J = 8.9 Hz, 1H), 7.20 (s, 1H), 7.25‒7.26 (m, 1H), 7.31‒7.35 (m, 2H), 7.37 (d, J = 2.1
Hz, 1H), 7.44 (d, J = 7.6 Hz, 1H), 7.47 (s, 1H), 7.52 (dd, J = 8.6 and 1.8 Hz, 1H), 7.69 (d, J = 7.5
Hz, 1H), 7.74 (d, J = 8.2 Hz, 1H), 8.36 (d, J = 8.3 Hz, 1H), 8.62 (d, J = 8.3 Hz, 1H), 8.89 (s, 1H),
13
9.21 (s, 1H); C NMR (CDCl3)
δ = 14.07, 22.52, 24.26, 27.10, 27.28, 29.14, 30.73, 31.27, 31.52,
33.12, 35.39, 44.75, 47.00, 70.60, 107.99, 114.51, 114.78 (3C), 116.20, 119.73, 120.81, 120.84,
120.94, 122.17, 122.60, 124.28, 124.61, 125.04, 125.82, 127.16 (2C), 129.69, 132.87, 133.26,
134.77, 135.06, 136.05, 137.11, 137.65, 138.44, 139.52, 152.55, 153.44, 155.31, 158.55, 158.92,
163.15, 165.94, 168.84, two carbon peaks are missing due to overlapping with those of chloroform;
22

ACCEPTED MANUSCRIPT
FABMS (NBA) m/z 814 (MH+); Anal. Calcd for C53H43N5O2S: C, 78.20; H, 5.32; N, 8.60. Found:
77.98; H, 5.14; N, 8.47.
4.20.
Preparation of TiO2/Dye hybrid films and device assembly
F-doped SnO2 coated glass substrates (4 mm thickness, 13 ꢀ □‒1, Nippon Sheet Glass) were
used to prepare TiO2 photoelectrodes. A commercial titanium dioxide paste (PST-18NR, JGC
Catalysts and Chemicals Ltd.) was deposited onto the FTO glass by doctor blade technique and
subsequently sintered at 500 °C for 15 min to obtain the 8 µm thick mesoporous titanium dioxide
layer.14 After immersing the TiO2 films into 40 mM aqueous TiCl4 solution at 70 °C for 30 min, the
substrates were sintered at 500 °C for 30 min. The TiO2 electrodes were then immersed in the 0.2
mM dye solution (solvent: acetonitrile/t-butyl alcohol = 1 : 1 (v/v)) in the presence of
chenodeoxycholic acid (0.4 mM). The dye adsorption was performed under dark at 25 °C for 3 h.
(3a, 3d) or 6 h. (3b, 3c, 3e, and 3f). Pt-sputtered FTO glasses were used as counter electrodes. The
dyed-TiO2 electrode and counter electrode were assembled into a sandwich-type cell (active area: 5
mm × 6 mm) with a reported method.15 The composition of electrolyte solution was
3-methoxypropionitrile solution of 1,2-dimethyl-3-propylimidazolium iodide (0.6 M), I2 (0.05 M),
LiI (0.1 M), and 4-t-butylpyridine (0.05 M).
Acknowledgements
The authors thank Dr. Hidetoshi Miura of Chemicrea Co., Inc. for valuable discussion. This work
was partially supported by The Strategic Core Technology Advancement Program, “Supporting
Industry Program”.
Appendix A. Supplementary data
23

ACCEPTED MANUSCRIPT
Supplementary data related to this article can be found at https:/doi.00000000.
References
1.
(a) Ito S, Miura H, Uchida S, Takata M, Sumioka K, Liska P, Comte P, Péchy P, Grätzel M.
Chem Commun. 2008;5194‒5196;
(b) Horiuchi T, Miura H, Sumioka S, Uchida S. J Am Chem Soc 2004;126:12218‒12219;
(c) Horiuchi T, Miura H, Uchida S. Chem Commun. 2003;3036‒3037.
2. (a) Wang Z, Wang XF, Yokoyama D, Sasabe H, Kido J, Liu Z, Tian W, Kitao O, Ikeuchi T,
Sasaki S. J Phys Chem C. 2014;118:14785‒14794;
(b) Ozawa H, Okuyama Y, Arakawa H. RSC Adv. 2013;3:9175‒9177;
(c) Nguyen LC, Mulmudi HK, Sabba D, Kulkarni SA, Batabyal SK, Nonomura K, Grätzel M,
Mhaisalkar SG. Phys Chem Chem Phys. 2012;14:16182‒16186;
(d) Tanaka H, Takeichi A, Higuchi K, Motohiro T, Takata M, Hirota N, Nakajima J, Toyoda
T. Solar Energy Materials & Solar Cells. 2009;93:1143‒1148.
3.
(a) Monti S, Pastore M, Li C, Angelis FD, Carravetta V. J Phys Chem C. 2016;120:2787‒
2796;
(b) Mottram AD, Lin YH, Pattanasattayavong P, Zhao K, Amassian A, Anthopoulos TD.
ACS Applied Materials & Interfaces. 2016;8:4894‒4902;
(c) Agrawal S, Leijtens T, Ronca E, Pastore M, Snaith H, Angelis FDe. J Mater Chem
A. 2013;1:14675‒14685.
4.
(a) Matsui M, Tanaka N, Kubota Y, Funabiki K, Jin J, Higashijima S, Miura H, Manseki K.
RSC Adv. 2016;6:33111‒33119;
(b) Higashijima S, Inoue Y, Miura H, Kubota Y, Funabiki K, Yoshida T, Matsui M. RSC
Adv. 2012; 2:2721‒2724;
(c) Higashijima S, Miura H, Fujita T, Kubota Y, Funabiki K, Yoshida T, Matsui M.
Tetrahedron. 2011;67:6289‒6293;
(d) Matsui M, Tanaka N, Kubota Y, Funabiki K, Jin J, Higashijima S, Miura H, Manseki K.
RSC Adv. 2016;3:33111‒33119.
24

ACCEPTED MANUSCRIPT
Matsui M, Asamura Y, Kubota Y, Funabiki K, Jin J, Yoshida T, Miura H. Tetrahedron.
5.
2010;66: 7405‒7410.
6.
7.
8.
Dentani T, Kubota Y, Funabiki K, Jin J, Yoshida T, Minoura H, Miura H, Matsui M. New J
Chem. 2009;33:93‒101.
Matsumoto S, Aoki T, Suzuki T, Akazome M, Betto A, Suda Y, Bull Chem Soc Jpn.
2012;85:1329‒1331.
Shibayama N, Inoue Y, Abe M, Kijiyama S, Ozawa O, Miura H, Arakawa H. Chem
Commun. 2015;51:12795‒12798.
9.
Pettit LD, Royston A, Whewell RJ. J Chem Soc A. 1968;2009‒2012.
10. Pavlishchuk VV, Addison AW. Inorg Chim Acta. 2000;298:97‒102.
11. (a) Hagfeldt A, Boschloo G, Sun L, Kloo L, Pettersson H. Chem Rev. 2010;110:6595‒6663.
(b) Mishra A, Fischer MKR, Bäuerle P. Angew Chem Int Ed. 2009;48:2474‒2499.
12. Matsui M, Aoki R, Kubota K, Funabiki K, Jin J, Yoshida T, Higashijima S, Miura H. RSC
Adv. 2015;5:57721‒57724.
13. Choi J, Kim SH, Lee W, Chang JB, Namgoong JW, Kim YH, Han SH, Kim JP. Dyes Pigm.
2014;101:186‒195.
14. Ito S, Zakeeruddin SM, Humphry-Baker R, Liska P, Charvet R, Comte P, Nazeeruddin MK,
Péchy P, Takata M, Miura H, Uchida S, Grätzel M. Adv Mater. 2006;18:1202‒1205.
15. Manseki K, Kondo Y, Ban T, Sugiura T, Yoshida T. Dalton Trans. 2013;42:3295‒3299.
25

ACCEPTED MANUSCRIPT
Highlights
Indoline dyes showing λmax in the range of 561 to 821 nm.
Best indoline sensitizer among six analogues.
Importance of energy levels, fluorescence lifetime, and stability as sensitizers.