Syntheses and Optoelectronic Properties of Planar Compounds 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine

Article abstract of DOI:10.1002/jhet.2491

Planar molecules 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocines would be potential acceptor materials of organic solar cell because of their containing SN units. One-pot synthetic procedures of 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine compounds are developed t

Full text of DOI:10.1002/jhet.2491

Month 2015 Syntheses and Optoelectronic Properties of Planar Compounds 3,7-diaryl-
1,5,2,4,6,8-dithiotetrazocine
a
a
a
a
b
*
*
Chao-Zhi Zhang, Dan Shen, Yang Yuan, Shi-Juan Li, and Hui Cao
aDepartment of Chemistry, Nanjing University of Information Science and Technology, Nanjing 210044, China
bJiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Nanjing University of
Information Science and Technology, Nanjing 210044, China
*
E-mail: chzhzhang@sohu.com; yccaoh@hotmail.com
Received March 24, 2015
DOI 10.1002/jhet.2491
Published online 00 Month 2015 in Wiley Online Library (wileyonlinelibrary.com).
Planar molecules 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocines would be potential acceptor materials of or-
ganic solar cell because of their containing SN units. One-pot synthetic procedures of 3,7-diaryl-1,
5,2,4,6,8-dithiotetrazocine compounds are developed to improve their yields up to 2.1–5.9 times as much
as those in literatures. The geometries of title compounds were optimized by the density functional theory
calculations. Their optoelectronic properties were studied by ultraviolet and cyclic voltammetry spectra
and fluorescence quenching experiments. The highest occupied and lowest unoccupied molecular orbital
energy level values show that these compounds are suitable to be employed as acceptor materials for devel-
oping bulk heterojunction organic solar cells with high open circuit voltages. Emission fluorescence of poly
(3-hexylthiophene) at excited state in dichloromethane was quenched by addition of title compound. There-
fore, these compounds used as acceptor materials could exhibit good mobility.
J. Heterocyclic Chem., 00, 00 (2015).
INTRODUCTION
(0.55–0.64V) [20,21]. Therefore, many non-fullerene
small-molecule acceptor compounds were designed and
synthesized to improve Voc of BHJ organic solar cells
[20–24]. However, PCE values of BHJ organic solar cells
fabricated by these organic acceptor compounds and
P3HT are low in spite of their high Voc values [22,23]. Be-
cause short circuit current (Jsc) values of these organic so-
lar cells are low because of low mobility of acceptor
materials and unsuitable size of phases aggregated by ac-
ceptor molecules [24]. In efficient BHJ solar cells with
high Jsc values, acceptor compounds should be aggregated
into acceptor material phases with suitable sizes [24–26].
Moreover, acceptor materials should exhibit a good mobil-
ity [24–26]. In general, planar acceptor compounds aggre-
gated easily into ordered geometries because of π–π
interaction among molecules [27,28]. Electrons would
transfer easily from one molecule to an adjacent molecule
in a J-aggregation [29–35]. Therefore, planar compounds
could be potential electron-acceptor materials with good
Organic solar cell materials have continuously drawn
great interest because of their several advantages, such as
cheap price, light weight, and easy combination and mod-
ification [1,2]. Designs and syntheses of desired organic
compounds for developing electron donor and acceptor
materials are fatal procedures in fabrication of bulk
heterojunction (BHJ) solar cells with high power conver-
sion efficiency (PCE) [3–6]. Generally, the desired organic
compounds should exhibit several characters, such as,
suitable band gap energy, good solubility, and mobility
[7–14]. In the past two decades, C60 or C70 derivatives
[15–18] were employed popularly as electron acceptor ma-
terials of organic solar cells since Wudl et al. synthesized
[6,6]-phenyl C61-butyric acid methyl ester (PCBM) in
1995 [19]. However, the lowest unoccupied molecular
orbital (LUMO) energy level is so low that open circuit
voltage (Voc) of BHJ organic solar cells fabricated by
poly(3-hexylthiophene) (P3HT) and PCBM is small
© 2015 HeteroCorporation

C.-Z. Zhang, D. Shen, Y. Yuan, S.-J. Li, and H. Cao
Vol 000
Scheme 1. Synthetic routes of 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine.
mobility. A planar electron acceptor with suitable LUMO
energy level could be desired for developing BHJ organic
solar cells with high Voc and Jsc. Many polymers containing
SN units are good electron conductor [4]. Acceptor mate-
rials aggregated by 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine
compounds could exhibit a high electron mobility because
of their containing SN units.
Planar molecules, 9,9′-bifluorenylidene (99′BF) deriva-
tives, are good electron acceptors, because geometries of
99′BF derivatives change reversibly when they gain or lose
electrons [18]. Moreover, BHJ solar cells fabricated by
P3HT:D99′BF (12-(3,6-dimethoxyfluoren-9-ylidene)-12H-
dibenzo[b,h]-fluorine) exhibited a high Voc (1.2V) [18].
The geometries of title compounds change reversibly, similar
to that of 99′BF, when they gain or lose electrons. The revers-
ible change when 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine
gain and lose electrons are shown in Figure 1.
Based on quantum chemistry calculations, geometries of
3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine were optimized
[36–50]. The calculation results show that these com-
pounds are planar. Therefore, these compounds could be
potential acceptor materials.
However, the synthetic methods of 3,7-diaryl-
1,5,2,4,6,8-dithiotetrazocine in literatures were complex
[37–42]. Moreover, the yields of these compounds were
very low. Therefore, developing an efficiently synthetic
procedure would be very important to acquire the practical
electron acceptor materials. In this paper, an one-pot proce-
dure that tri(trimethylsilyl)arylamidine reacted with SCl2 to
directly synthesize title compounds is reported to improve
the yields from 2.4%–9.0% in literatures [37–42] to
5.1%–29.3%.
1,2,3,5-dithiadiazolium chloride was 10%–15%. Although
the yield of the reaction of 4-phenyl-1,2,3,5-dithia-
diazolium chloride with oxygen gas was 40%–60%. In
the one-pot synthesis, intermediate 4-aryl-1,2,3,5-
dithiadiazolium chloride was not separated from solution
so that the total yields of compound 1, 2, and 3 are
28.6%, 29.3%, and 5.1%, respectively. Moreover, pure
3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine was acquired con-
veniently from reactive solution by filtration instead of
chromatography in literatures [37–39]. Therefore, the
one-pot synthesis is an efficient and convenient procedure.
Molecular orbital energy levels.
The maximal
RESULTS AND DISCUSSIONS
absorption wavelength (λmax) and onset wavelength (λo)
in the UV–vis absorption spectra were summarized in
Table 1. Difference of energy levels between the LUMO
and highest occupied molecular orbital (HOMO) (Eg)
was defined in terms of the onset wavelength [46],
One-pot synthetic methods.
Synthetic routes of
compound 1, 2, 3, 4, and 5 were shows in Scheme 1.
Compound 1, 2, and 3 were synthesized respectively by
Boeré et al., [37] Gronowitz et al. [41], and Bond et al. [38]
The yields of compound 1, 2, and 3 were 5.4% [37], 5.0%
[39], and 2.4% [38], respectively, because of air-sensitive
intermediate, 4-aryl-1,2,3,5-dithiadiazolium chloride.
4-Aryl-1,2,3,5-dithiadiazolium chloride would decompose
when it exposed to air. Therefore, the total yield would
be low. For example, Scholz et al. synthesized compound
1 with a total yield 4%–9% [42]. The yield of 4-phenyl-
Eg ¼ hc=λo
(1)
where h is Plank’s constant, 6.626 × 10ꢀ34 J·s; c is the
speed of light; and λo is the onset wavelength.
Table 1
UV–vis absorption wavelengths and energy levels of the 3,7-diaryl-
1,5,2,4,6,8-dithiotetrazocines.
λmax
λo
Ere
ELUMO
EHOMO
Eg
No.
(nm)
(nm)
(eV)
(eV)
(eV)
(eV)
1
2
3
4
5
411
448
423
451
455
445
485
447
495
500
ꢀ1.40
ꢀ1.30
ꢀ1.35
ꢀ1.20
ꢀ1.20
ꢀ3.45
ꢀ3.55
ꢀ3.50
ꢀ3.65
ꢀ3.65
ꢀ6.25
ꢀ6.10
ꢀ6.27
ꢀ6.15
ꢀ6.13
2.80
2.55
2.77
2.50
2.48
Figure 1. The structures of title compounds and those with a seized
electron.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2015
Syntheses and Optoelectronic Properties of Planar Compounds 3,7-diaryl-
1,5,2,4,6,8-dithiotetrazocine
The LUMO energy level values of the acceptors
were estimated from the reduction potential onset
(ELUMO = ꢀ(Ere + EFc+/Fc) = ꢀ(Ere + 4.85)), whereas the
HOMO energy levels (EHOMO) were calculated from the
ELUMO values and the Eg values (EHOMO = ELUMO ꢀ Eg).
The results were summarized in Table 1.
In Table 1, HOMO energy levels of the 3,7-diaryl-
1,5,2,4,6,8-dithiotetrazocines (ꢀ6.10 toꢀ 6.27 eV) are
similar to that of PCBM (ꢀ6.1 eV). LUMO energy levels
of these compounds (ꢀ3.45 to ꢀ3.65eV) are 0.65–
0.85eV higher than that of PCBM (ꢀ4.3 eV). HOMO
and LUMO energy levels of most of donors were
ꢀ4.90 eV to ꢀ5.5 eV and ꢀ2.90eV to ꢀ3.4 eV, respec-
tively [47,48]. Therefore, the organic BHJ solar cell fabri-
cated by 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine and P3HT
could exhibit a high open circuit voltage.
HOMO energy level of compound 3 (ꢀ6.27eV) is
slightly lower than that of compound 1 (ꢀ6.25eV). Simi-
larly, HOMO energy level of compound 4 (ꢀ6.15eV)
and compound 5 (ꢀ6.13eV) are slightly lower than that
of compound 2 (ꢀ6.10eV). Because bromo is a weak
electron-withdrawing group so that HOMO energy levels
of bromoaryl compounds are lower than that of correspond-
ing aryl compounds, respectively. Because of the effect of
bromo substituent on energy level of compound, LUMO en-
ergy levels of compound 4 (ꢀ3.65 eV) and 5 (ꢀ3.65eV) are
0.1eV lower than that of compound 2 (ꢀ3.55eV). LUMO
energy level of compound 3 (ꢀ3.50eV) is 0.05eV lower
than that of compound 1 (ꢀ3.45eV). The reduced values
(0.05eV–0.10eV) of LUMO energy levels of these com-
pounds are larger than those of corresponding HOMO en-
ergy levels (0.02eV–0.05eV). As a result, the difference
between LUMO and HOMO energy levels of bromoaryl
compounds would be smaller than those of corresponding
aryl compounds, respectively. Therefore, LUMO and
HOMO energy levels would be effective tuned by introduc-
ing bromo substituent to aryl rings [49].
π-conjugated well of 1,5,2,4,6,8-dithiotetrazocine and
thienyl rings. Therefore, the compounds would be
π-stacked regularly so that electrons would transfer easily
from one acceptor to another. The CV spectrum shows
that the 3,7-di[2-thienyl]-1,5,2,4,6,8-dithiotetrazocine
can accept and lose electrons reversibly. CV and UV
spectra of compound 1, 3, 4, and 5 are similar to those of
3,7-di[2-thienyl]-1,5,2,4,6,8-dithiotetrazocine. Therefore,
3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine would be potential
acceptors for developing BHJ organic solar cells.
Fluorescence quenching experiments. The fluorescence
quenching experiments were performed. Percentages of
the fluorescence quenching increase with weights of the
added acceptors increasing. The fluorescence was almost
completely quenched when the weight of the acceptor
compound was 3 times as much as that of P3HT. In order
to study on variety in the fluorescence quenching when
different acceptor was added, the weight of the added
acceptor compound was a third as much as that of P3HT.
In Figure 3, the black line was the fluorescent emission
spectrum of a solution of P3HT in CH2Cl2. The red, green,
Figure 3. Fluorescence quenching experiments of 3,7-diaryl-1,5,2,4,6,8-
dithiotetrazocines. [Color figure can be viewed in the online issue, which
is available at wileyonlinelibrary.com.]
Part b in Figure 2 shows clearly that there is an absorp-
tion peak in range from 400 nm to 500nm because of
Figure 2. CV and UV of compound 2.
Journal of Heterocyclic Chemistry
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C.-Z. Zhang, D. Shen, Y. Yuan, S.-J. Li, and H. Cao
Vol 000
The geometries of 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocines. In
Scheme 2, dihedral angles of compound 1, 2, 3, 4, and 5
between aryl rings and 1,5,2,4,6,8-dithiotetrazocine ring
are 1.90°, 0.00°, 0.56°, 0.00°, and 0.00°, respectively.
Dihedral angles of compound 1, 2, 3, 4, and 5 with a
seized electron between aryl rings and 1,5,2,4,6,8-
dithiotetrazocine ring are 0.08°, 0.04°, 0.03°, 0.00°, and
0.00°, respectively. Therefore, all structures of title
compounds and that with a seized electron are planar.
Two aryl rings and 1,5,2,4,6,8-dithiotetrazocine ring are
coplanar so that whole molecule is π-conjugated well.
Therefore, these acceptor compounds would aggregate
into J-aggregation through π–π stacking [37,38]; as a
result, electrons would transfer easily from a molecule to
blue, and slight blue lines were respectively the fluorescent
emission spectra of solution of P3HT and acceptor 1, 2, 3,
or 5 in CH2Cl2. The weight of the title compound was 1/3
weight of P3HT. Figure 3 shows clearly that emission fluo-
rescence of P3HT in excited state was reduced respectively
27%, 37%, 43%, and 83% when compound 1, 2, 3, or 5
was added respectively into a solution of P3HT in CH2Cl2.
These curves show that an excited electron in P3HT was
easily transferred to 1,5,2,4,6,8-dithiotetrazocine deriva-
tive so that P3HT recovered from excited state to ground
state. As a result, the emission fluorescence of P3HT at
excited state was reduced. Therefore, acceptor materials
aggregated by these compounds could exhibit high
mobility.
Scheme 2. Geometries of 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocines. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2015
Syntheses and Optoelectronic Properties of Planar Compounds 3,7-diaryl-
1,5,2,4,6,8-dithiotetrazocine
Synthesis of 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocines. 3,7-
Diphenyl-1,5,2,4,6,8-dithiotetrazocine (1).
an adjacent molecule [31–35]. Because hydrogen bond was
formed between a hydrogen atom in thienyl (or phenyl)
ring and a nitrogen atom in 1,5,2,4,6,8-dithiotetrazocine
ring; as a result, thienyl (or phenyl) ring is in 1,5,2,4,6,8-
dithiotetrazocine ring plane. These hydrogen bonds and
π–π stacking interactions result that the 3,7-
diaryl-1,5,2,4,6,8-dithiotetrazocine was stacked up to
J-aggregation, which is useful property for developing BHJ
solar cell with high PCE. [9,32–35,50] When a 1,5,2,4,6,8-
N,N,N′-Tri
(trimethylsilyl)benzamidine was synthesized similar to the
literature [40]. Benzonitrile (4.4g, 42.7mmol) was added
into Et2O (100mL). The result solution was added
dropwise into another solution of (Me3Si)2NLi·OEt2
(10.8g, 45.8mmol) in Et2O (160mL). The reaction
solution was refluxed for 24h. The ether was distilled off,
and toluene (40mL) was added. Then, a solution of
ClSiMe3 (4.87g, 45.8mmol) in toluene (15mL) was added
into the reaction solution. The reaction mixture was
refluxed for 5h. After cooling to room temperature, deposit
LiCl was separated from the light orange solution by
filtration. The solvent toluene was removed by distillation.
The tri(trimethylsilyl)benzamidine was acquired by vacuum
distillation (91–93°C, 3mmHg) as a white crystal (11.0g,
73.6%). 1H NMR (DCCl3): δ=7.23 (s, 5H), 0.002 (s, 27H).
Compound 1 was synthesized by one-pot method. Tri
(trimethylsilyl)benzamidine (3.6g, 9.4mmol) and SCl2
(4mL, 7.2g, 69.9mmol) were added into CH3CN
(100 mL). The result solution was heated and stirred at 60°C
for 2h. Excess SCl2 was removed from the reaction solution.
SbPh3 (3.6g, 10.3mmol) in CH3CN (50mL) was added
dropwise into the reaction solution. At 60°C, air was led in
the reaction bottle for 18h. The mixture was filtered to get
a pure 3,7-diphenyl-1,5,2,4,6,8-dithiotetrazocine, a yellow-
green plate-like crystal (0.40g, 1.3mmol, 28.6%). IR spec-
dithiotetrazocine derivative accepted
a electron, the
structures of 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine with a
seized electrons would keep planar structure. When seized
electrons transferred to cathode, the structures of 3,7-
diaryl-1,5,2,4,6,8-dithiotetrazocine would be recovered
reversibly.
CONCLUSION
A one-pot synthetic method is reported to prepare 3,7-
diaryl-1,5,2,4,6,8-dithiotetrazocines for developing accep-
tor materials of organic solar cell. CV and UV–vis spectra
were determined for calculating their LUMO and HOMO
energy levels. The HOMO and LUMO energy level values
show that these compounds are suitable to be employed as
acceptor materials for developing organic BHJ solar cells
with high open circuit voltages. The results of fluorescence
quenching experiments show that the electrons were trans-
ferred spontaneously from P3HT to 3,7-diaryl-1,5,2,4,6,8-
dithiotetrazocine. Results of theoretical calculations show
the geometries of 3,7-diaryl-1,5,2,4,6,8-dithiotetrazocines
and those with seized electrons are planar and change
reversibly when they gain or lose electrons. Results of both
theoretical calculation and fluorescence quenching suggest
that acceptor materials aggregated by 3,7-diaryl-1,5,2,4,6,8-
dithiotetrazocine would exhibit high mobility. This paper
suggests a useful way of developing desired acceptor mate-
rials for organic BHJ solar cell.
1
trum of the compound is according with literature [37]. H
NMR (DCCl3): δ=8.54 (d, J=8.6Hz, 4H), 7.60–7.42 (m,
6H). MS (EI): m/z=298 (M+), 135 ([PhCNS2]+); calcd for
C14H10N4S2 [M+]: 298.3. Elem. Anal. Calcd. for
C14H10N4S2 (298.3): C, 56.38; H, 3.37, N, 18.73; S, 21.49.
Found: C, 56.35, H, 3.38, N, 18.78; S, 21.53. IR (KBr):
υ =1696 (S¼N), 1618 (C¼N), 1593 and 1489 (C¼C) cmꢀ1
.
3,7-Di(2-thienyl)-1,5,2,4,6,8-dithiotetrazocine (2).
N,N,N′-
Tri(trimethylsilyl)-2-thienylamidine was synthesized similar
to N,N,N′-tri(trimethylsilyl)benzamidine. 2-Thiophenonitrile
was employed to replace benzonitrile. The N,N,N′-
tri(trimethylsilyl)-2-thienylamidine was acquired by vacuum
distillation (118–120°C, 3mmHg) as a yellow liquid
(60.2%).
EXPERIMENTAL
Materials and methods.
Melting points were
Similar to the synthetic method of compound 1, compound
2 was synthesized by one-pot method. It was acquired as yel-
low crystal (29.3%). IR spectrum of the compound is accord-
ing with literature.40 1H NMR (DCCl3): δ =7.92 (d, J=4.0Hz,
2H), 7.48 (d, J=5.0 Hz, 2H), 7.18 (dd, Ja =4.0Hz, Jb =5.0Hz,
2H). MS (ESI): m/z=311 [M =1]+; calcd for C10H6N4S4 [M
+1] +: 311.0. Elem. Anal. Calcd. for C14H10N4S2 (310.4): C,
38.74, H, 1.96, N, 18.03; S, 41.32. Found: C, 38.69, H, 1.95,
N, 18.05; S, 41.34. IR (KBr): υ =1662 (S¼N), 1608 (C¼N),
determined on a Yanaco micro melting point apparatus
(uncorrected). 1H NMR were recorded on Bruker AM
300 (Germany), and δ were given in ppm (relative to
TMS) and coupling constants (J) in Hz. Mass spectra
were recorded by a GCMS-QP2010 gas chromatogram
mass spectrometer under GC/MS mode. UV–visible
spectra were recorded on a Lambda 25 Perkin-Elmer
spectrophotometer. IR spectra were recorded on a
Brucker Vector 22 spectrophotometer, in which samples
were embedded in KBr thin films. Precoated silica gel
plates (GF254) were used for analytical TLC. All
solvents were purified by standard procedures. All
chemicals were purchased from Sigma or Aldrich.
1430 (C¼C in thiophene) cmꢀ1
.
3,7-Di(4-bromophenyl)-1,5,2,4,6,8-dithiotetrazocine (3). N,N,
N′-Tri-(trimethylsilyl)-4-bromobenzamidine was synthesized
similar to N,N,N′-tri(trimethylsilyl)-benzamidine. 4-
Bromobenzonitrile was employed to replace benzonitrile.
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C.-Z. Zhang, D. Shen, Y. Yuan, S.-J. Li, and H. Cao
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The N,N,N′-tri(trimethylsilyl)-4-bromobenzamidine was
acquired by vacuum distillation (150–153°C, 3 mmHg)
as a light green crystal (68.2%).
scan rate was 100mVsꢀ1. Ferrocene was added to the
sample solution at the end of the experiment. The
ferrocenium/ferrocene (Fc+/Fc) redox couple was used as an
internal potential reference (EFc+/Fc = 4.85eV). The potential
in CH2Cl2 was calibrated according to literature [43,44].
Similar to the synthetic method of compound 1, com-
pound 3 was synthesized by one-pot method. It was
acquired as a yellow solid (5.1%). IR spectrum of the com-
pound is according with literature.39 1H NMR (DCCl3):
δ= 8.43 (d, 4H, J= 8.8 Hz), 7.69(d, 4H, J = 8.8Hz). MS
(FI)+: m/z= 455.9; 457.9; 453.9 (M+; Abundance ra-
tio= 2:1:1); calcd for C14H8Br2N4S2 [M+]: 455.9, 457.9,
453.9 (Abundance ratio =2:1:1). Elem. Anal. Calcd. for
C14H8Br2N4S2 (456.2): C, 36.86; H, 1.77; N, 12.28; S,
14.06. Found: C, 36.83, H, 1.77, N, 12.24; S, 14.08. IR
(KBr): υ =1658 (S¼N), 1583 and 1479 (C¼C in benzene
Fluorescence quenching experiment.
At room
temperature, the fluorescence quenching experiments were
performed by fluorescence spectrometry [45] (CaryEclipse,
Varian Co. USA). P3HT (30mg) was added into THF
(10mL) for determining fluorescence of the solution. Then
3,7-diaryl-1,5,2,4,6,8-dithiotetrazocine (10mg) was added
the above solution for determining fluorescence quenching
of the solution.
Computational details.
Geometries of 3,7-diaryl-
ring) cmꢀ1
.
1,5,2,4,6,8-dithiotetrazocine were optimized by the
density functional theory (DFT) calculations using
Gaussian03 software at the B3LYP/6-31G(d) level [36,51].
3-(4-Bromothiophen-2-yl)-7-(thiophen-2-yl)-1,5,2,
4,6,8-dithiotetrazocine (4). 3,7-Di(2-thienyl)-1,5,2,4,6,8-
dithiotetrazocine (0.2 g, 0.65 mmol) and NBS (0.267g,
1.5mmol) was added into 1,2-dichlorobenzene (40 mL),
and the solution was heated up to 120°C for 30 h. The
solvent was removed, and MeOH (30 mL) was added.
Acknowledgments. This work was supported by Jiangsu Specially-
Appointed Professor Program (R2012T01), Foundation for
special project on the Integration of Industry, Education, and
Research of Jiangsu Province (BY2012028), Scientific Research
Foundation for Returned Scholars from Ministry of Education of
China (2013S010), the Priority Academic Program Development
of Jiangsu Higher Education Institutions, and CICAEET.
The mixture was filtered to get
a yellow pure
compound (228 mg, 90.1%). 1H NMR (DCCl3):
δ= 7.93 (d, J = 4.0 Hz, 1H), 7.70 (d, J = 4.0 Hz, 1H),
7.51 (d, J = 4.0 Hz, 1H), 7.18 (dd, J = 4.0 Hz, 1H), 7.13
(d, J = 4.0 Hz, 1H). MS (FI)+: m/z = 389.9, 387.9 (M+;
Abundance ratio = 1:1); calcd for C10H5BrN4S4 [M+]:
387.9, 389.9 (Abundance ratio = 1:1). Elem. Anal.
Calcd. for C10H5BrN4S4 (389.3): C, 30.85; H, 1.29; N,
14.39; S, 32.94. Found: C, 30.89; H, 1.30; N, 14.38;
S, 32.96. IR (KBr): υ= 1675 (S = N), 1605 (C = N),
1530 and 1425 (C = C in thiophene) cmꢀ1
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3,7-Di(4-bromothiophen-2-yl)-1,5,2,4,6,8-dithiotetrazocine
(5). 3,7-Di(2-thienyl)-1,5,2,4,6,8-dithiotetrazocine (0.2g,
0.65mmol) and NBS (0.445g, 2.5mmol) were added into
1,2-dichlorobenzene (40mL). The reaction mixture was
heated up to 170°C for 15h. The solvent was removed.
Then, MeOH (30mL) was added. Mixture was stirred for
30min. The mixture was filtered to get yellow pure
1
compound (259mg, 85.1%). H NMR (DCCl3): δ=7.71
(d, J=4.0Hz, 2H), 7.12 (d, J=4.0Hz, 2H). MS (FI)+:
m/z=467.8, 469.8, 465.8 (M+; Abundance ratio=6:4:3);
calcd for C10H4Br2N4S4 [M+]: 467.8, 469.8, 465.8
(Abundance ratio=6:4:3). Elem. Anal. Calcd. for
C10H4Br2N4S4 (468.2): C, 25.65; H, 0.86; N, 11.97; S,
27.39. Found: C, 25.63; H, 0.86; N, 11.95; S, 27.41. IR
(KBr): υ=1701 (S¼N), 1598 (C¼N), 1530 and 1422
(C¼C in thiophene) cmꢀ1
.
Cyclic voltammetry experiment. At room temperature,
cyclic voltammetry was performed using an electrochemical
workstation (CH instruments Inc., CHI, model 750A) and
conducted
using
0.1 molLꢀ1
tetrabutylammonium
perchlorate (TBAP) as the supporting electrolyte. The
working, auxiliary, and reference electrodes were a glassy
carbon electrode, a Pt wire and Ag/Ag+, respectively. The
[16] Meng, X.; Zhang, W.; Tan, Z.; Li, Y.; Ma, Y.; Wang, T.;
Jiang, L.; Shu, C.; Wang, C. Adv Funct Mater 2012, 22, 2187.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2015
Syntheses and Optoelectronic Properties of Planar Compounds 3,7-diaryl-
1,5,2,4,6,8-dithiotetrazocine
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet