Novel fluorescent N,O-chelated fluorine-boron benzamide complexes containing thiadiazoles: Synthesis and fluorescence characteristics

Article abstract of DOI:10.1016/j.tet.2017.08.023

A series of N-(5-phenyl-1,3,4-thiadiazol-2-yl)benzamide derivatives and their corresponding BF₂ complexes were synthesized, and their photophysical properties were determined. The effect of the derivatives with various substituents on the benza

Full text of DOI:10.1016/j.tet.2017.08.023

Accepted Manuscript
Novel fluorescent N,O-Chelated fluorine-boron benzamide complexes containing
thiadiazoles: Synthesis and fluorescence characteristics
Kan Zhang, Hao Zheng, Chaojun Hua, Ming Xin, Jianrong Gao, Yujin Li
PII:
S0040-4020(17)30854-2
10.1016/j.tet.2017.08.023
TET 28917
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 9 May 2017
Revised Date: 13 August 2017
Accepted Date: 14 August 2017
Please cite this article as: Zhang K, Zheng H, Hua C, Xin M, Gao J, Li Y, Novel fluorescent N,O-
Chelated fluorine-boron benzamide complexes containing thiadiazoles: Synthesis and fluorescence
characteristics, Tetrahedron (2017), doi: 10.1016/j.tet.2017.08.023.
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ACCEPTED MANUSCRIPT
Novel Fluorescent N,O-Chelated Fluorine-Boron Benzamide
Complexes Containing Thiadiazoles: Synthesis and fluorescence
characteristics

ACCEPTED MANUSCRIPT
Novel Fluorescent N,O-Chelated Fluorine-Boron Benzamide
﹥
Complexes Containing Thiadiazoles: Synthesis and fluorescence
characteristics
Kan Zhang, Hao Zheng, Chaojun Hua, Ming Xin, Jianrong Gao, Yujin Li*
College of chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, People's
Republic of China
Corresponding authors.
E-mail addresses: lyjzjut@zjut.edu.cn (Y. Li).
Telephone number: +86-0571-88320891 (Y. Li).
ABSTRACT
A series of N-(5-phenyl-1,3,4-thiadiazol-2-yl)benzamide derivatives and their
corresponding BF2 complexes were synthesized, and their photophysical properties
were determined. The effect of the derivatives with various substituents on the
benzamide ring and phenyl-1, 3, 4-thiadiazole ring were examined in different organic
solvents and in the solid state. These dyes enjoy a series of excellent photophysical
properties including the large Stokes shift, solid-state fluorescence, and
aggregation-induced emission effect (AIEE).
Keywords:
BF2 complexes; blue fluorescence; solid state; Stokes shifts; quantum yield;AIEE.
1. Introduction
Organic fluorine-boron complexes carrying the BF2 moiety are known to be
fluorescent. [1] Among them, the boron-dipyrromethene (BODIPY) as the best-known
example, are a family with excellent fluorescent properties.[2] They exhibit high
fluorescence quantum yield, outstanding optical properties and sharp fluorescence
spectra [3,4] and are often applied to electroluminescent devices, [5] dye-sensitized solar
[8]
[9]
cells,[6,7] liquid crystals,
biological imaging
and laser dyes.[10] Among these,
heterocyclic azo dyes have been widely investigated mostly due to they are versatile
chromophores that can provide bright strong shades tunable for absorption
spectrum.[11] And azo dyes are of particular interest because the planarity of the azo
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bridge combines with benzoyl or other systems should contribute to larger π electron
transmission effects and lead to higher optical activity.[12,13]These previous studies
prompted us to the synthesis and the characterization of new thiadiazoles N-O BF2 as
suitable candidates for potential use in fluorescent dyes.
In recently years, BF2 fluorescence complexes have attracted significant attention
due to their outstanding optical properties.[14]However, in many cases, these dyes
exhibit decreased fluorescence in the solid state as a result of aggregation-caused
quenching(ACQ) ,[15]which owing to the formation of delocalised excitons or
excimers cause enhanced non-radiative deactivation of the excited state.[16,17]We
design these boron fluoride complexes of thiadiazoles (3b) have showed nice
fluorescence in solution sate and solid sate, however, we also find these boron
fluoride complexes(3a,3d) exhibit intense solid fluorescence but weak in solution. In
contrast of aggregation-caused quenching(ACQ) ,[18] the unusual phenomenon of the
luminescence aggregate state stronger than that in the solution state,[19]called
aggregation-induced emission effect (AIEE),[20] which is now attracting increasing
research attention. These compounds(3a,3d) which have the AIEE characteristics
exhibit weak luminescence in solution state, but show highly emissive behaviour in
their aggregated and solid states. The results showed that thiadiazoles derivatives and
their BF2 complexes displayed attractive luminescent properties. [21,22]
2. Results and discussion
2.1. Synthesis
Preparation of the N-(5-phenyl-1, 3, 4-thiadiazol-2-yl)benzamide derivatives 2
and their corresponding BF2 complexes 3 were shown in Scheme 1. Benzamide
[24]
derivatives 2 were prepared following a patent method
by amidation of
2-aminobenzothiazole with benzoyl chloride (1.2 equiv.) at room temperature which
resulted in more than 83% yields. The BF2 complexes 3 were produced, with the
yields of 41%-74%, by using an excess of BF3·OEt2 in toluene with Et3N as the base
and purification by column chromatography. All the structures of boron complexes
were fully characterized by FTIR, 1H NMR, 13C NMR and HRMS analysis.
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Scheme 1. Synthesis of benzamide 2, BF2 complexes 3
2.2. Fluorescence detection
2.2.1. UV-Vis and fluorescence of 3a in solution
The end product BF2 complexes 3 showed good solubility and stability in organic
solvents such as dichloromethane (DCM), chloroform, toluene, EtOH, THF and
N,N-dimethylformamide. By testing, no observable color and fluorescence fading was
found over months. The solvent effect on the absorption and fluorescence properties
of 3a were examined. As shown in Table 1 and Fig. 1, complex 3a exhibited a sharp
absorption peak at about 330 nm in organic solvents, and the λmax was barely affected
by solvent polarity, suggesting that the dipole moments of the molecules in their
ground and excited states were almost equal.[25] While the fluorescence intensity were
strongly dependent on solvents and reduced with the increase in solvent polarity.In
Fig. 1(b), 3a showed the highest emission curve in toluene . So we chose toluene to
examine the absorption and fluorescence properties of all the BF2 complexes 3.
Fig. 1. Absorption spectrum (a) and emission spectrum (b) of complex 3a (3×10-6
mol·L-1) in different solvents (PMT Voltage: 500 V).
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Table 1. Optical data of 3a-3d in solvents and in the solid state.
Dye Matrix
UV-Vis
εmax(M-1·cm-1)
33667
Fluorescence
Stokes shift
λabs(nm)
335
337
333
332
328
330
331
334
367
356
369
343
349
370
λem(nm)
ФF
(nm)
78
73
79
70
81
85
80
85
62
58
77
66
87
86
3a
CHCl3
toluene
DCM
THF
413
410
412
402
409
415
411
419
429
414
446
409
436
456
0.05
0.06
0.03
0.02
0.01
<0.01
0.01
0.01
36000
33000
32333
EtOH
MeCN
EA
29667
34000
33333
DMF
solid
36667
3b
toluene
solid
46667
0.29
3c
toluene
toluene
solid
25000
25333
<0.01
3d
0.16
2.2.2. Optical Properties of complexes 3 in solution
The UV−vis absorption and normalized fluorescence spectra of 3a-3d in toluene
are shown in Figures 2. The maximum absorption wavelength of complex 3 compared
to that of amide 2 (Table 1), although amide 2 did not show fluorescence, complex 3
exhibited blue fluorescence at 410 nm-436nm. The fluorescence quantum yields (ФF)
of 3a in toluene was 0.06 and the Stokes shift was 73nm. The λmax of 3b (356 nm), 3c
(343 nm), 3d (349 nm) was slightly red-shifted, and εmax(3b) was higher (46667)
compared to that of 3a (337nm and 36000), respectively. But, 3c (25000), 3d (25333)
showed decrease in εmax. It is worth noting that the fluorescence quantum yields were
highly dependent on the substituents on the aromatic ring. In the absence of
substitution at the right aromatic ring, low quantum yield (0.06) was observed and
introducing electron-withdrawing (NO2) onto the para-position of right phenyl
ring(3c) got lower quantum yield(<0.01). However, introducing an electron-donating
methoxy group onto the para-position of right phenyl ring (complex 3b), the quantum
yield increased to 0.29. In addition, we could observe high quantum yield 0.16(3d)
which introducing electron-donating methoxy group onto the para-position of left
phenyl ring. This suggested that we could construct push-pull-type architecture
through the introduction of an electron-donating group onto the phenyl ring.
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Fig. 2. Absorption spectrum and emission spectrum of complex 3a-3d (3×10-6 mol·L-1)
in toluene (PMT Voltage: 500 V).
Fig. 3. The color of compounds 3a-3d(1×10-4 mol·L-1)(left to right) in toluene under
UV lamp (365 nm).
2.2.3. Optical Properties of complexes 3 in the solid state
The BF2 complexes 3 were also emissive in the solid state and their emission data
were shown in Table. 1. Generally, the high planarity of BODIPY dyes may lead to
stacking of molecules causing quite strong intermolecular interactions resulting in the
concentration quenching in the solid state.[ 26, 27,28] Therefore, many BODIPY dyes
hardly display fluorescence in the solid state. By controlling the molecular structure,
we successfully obtained solid-state emissive benzamide-BF2 complexes 3. Photos of
the emission colors of 3a-3d in the solid state were provided for comparison (Fig. 5).
As shown in Table. 1, the fluorescence maxima for all complexes 3 were red-shifted
with respect to corresponding emissions in solution, which could be attributed to the
π-π stacking induced by the more compact molecular aggregation in the solid state [29]
.
As we see, the compounds 3a exhibited good blue fluorescence in solid-state but
weak fluorescence in solution. The electron-donating substituted compounds 3b, 3d
displayed better blue fluorescence in solid-state and had slightly red-shifted compared
to 3a. It was assumed that large Stokes shifts partly offset the self-quenching effect in
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the solid-state, and the more twisted molecular structure might prevent the molecules
from packing compactly, thus enhancing their solid emission [30]. In addition, the
nitro-substituted compound 3c display almost no fluorescence in the solid-state and
solution.
Fig. 4. The color of compounds 3a-3d (left to right) under visible light (upper row)
and UV lamp (365 nm, lower row).
2.2.4. Optical Properties of complexes 3 in the aggregated state
From the above test, we found compounds 3a and 3d had low quantum yield and
weak fluorescence in solution , but exhibited intense fluorescence in solid-state. So we
thought they have aggregation-induced emission effect (AIEE). To determine whether
compounds 3a and 3d have AIEE characteristics, the UV− Vis absorption spectra and
fluorescence spectra of compound 3a and 3d were measured in a series of H2O/THF
mixtures with different volume fractions of water, since compounds 3a and 3d was
soluble in THF but not in water (see Fig. 5). Compared with the UV−Vis spectrum of
compounds 3a in different mixtures of THF and water over 10 min, we found the
maximum absorption wavelength and intensity were no significant change when the
water was added (10-70% (v/v)) gradually. When the water fraction was between 80
and 90%, the maximum absorption wavelength also had no obvious change, but the
fluorescence intensity dramatically increased. As the water content increased to over
80% (v/v) in the H2O/THF mixture, despite its luminogen concentration remaining
unchanged at 1×10-4 mol·L-1, its fluorescence intensity was incredible strong compared
to in the THF solution. Similar results were observed for compound 3d. Since water
was a poor solvent for compounds 3a and 3d, the molecules of these compounds must
have aggregated in the H2O/THF mixture system at those higher water contents
(80-90% (v/v)). Therefore, compounds 3a and 3d were AIEE active. In addition,we
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could find emision wavelength of compound 3a in 90% (v/v) has litter red shift
compared to in 80% (v/v). We thought it was because of different
water
fractions(Fig.9 S13).
Fig.5. Emission spectra of 3a, 3d (1×10-4 mol·L-1) in different proportions of
H2O/THF
2.2.5. DFT calculation
Fig. 6. Representative HOMO and LUMO diagrams of 3a-3d obtained from
calculations and their corresponding energy levels
3a-1
Fig. 7. Representative optimized geometry of the compounds 3a from different
orientatio
3a-2
n
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Table 2. Calculation data of compounds 3a-3d.
λa
λb
λa
λb
abs
em
em
abs
c
c
compounds
fem
f abs
(nm, cal)
(nm,exp)
(nm,cal)
(nm,exp)
435
427
417
474
410
414
409
436
0.7176
0.9852
0.5156
0.5535
354
368
364
388
337
356
343
349
0.8870
1.1778
0.5777
0.6686
3a
3b
3c
3d
atheoretical calculations basis sets B3LYP/6-31G without solution
bλmaxin toluene solvent
cOscillator strength coefficients
In order to support our result we made the compounds geometry optimizations
using the density functional theory (DFT) method as implemented in Gaussian 09W
suite of programs employing basis sets B3LYP/6-31G.The ground-state geometry was
optimized in the gas-phase at the B3LYP/6-31G level of theory. From the DFT
calculations, we can see the HOMO and LUMO orbitals are delocalized over the
whole molecule(Fig.6). In the case of 3b, the terminal phenyl ring with methoxy
group significantly contribute to the delocalization. Therefore, complex 3b is
expected to have red-shifted λmax and high ε. The DFT calculations indicate that
methoxy derivative 3d shows intramolecular chargetransfer (ICT) transition from
methoxy group to the three-nitrogen ring of chelating position moiety[31]. The
red-shifted λmax of 3d are owing to the ICT transition. In contrast to 3d, we can see the
HOMO and LOMO of complex 3c shows intramolecular chargetransfer (ICT)
transition from the left benzene and three-nitrogen ring to the right benzene with nitro
group. Because of strong electron-withdrawing group, the orbitals are delocalized in
right benzene with nitro group. It can explain why the 3c show no fluorescence. From
the DFT calculations(Fig.7), we were aware that the molecular system formed a
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nearly planar structure. The absorption spectra and emission spectra were computed
using time-dependent DFT (TD-DFT). It is worth noting that the values of the
experiment absorption and emission spectra is in good agreement with the calculated
values (Table 2).
3. Conclusion
In summary, we have developed new N,O-chelated BF2 complex benzamide
derivatives containing thiadiazoles building blocks. The synthesis of these dyes
displayed solvent-sensitive emission feature and a nice quantum yield had been
achieved for 3b through the introduction of an electron-donating methoxy group onto
the phenyl ring. These compounds 3a, 3b and 3d also showed good solid-state
fluorescence. In particular, these complexes 3a and 3d displayed unusual
aggregation-induced emission enhancement in the mixed solvent of THF/water.
Moreover,These series of compounds could be applied to the design of OLEDs,
live-cell imaging and fluorescent sensors.
4. Experimental
4.1. Materials and equipment
Nuclear magnetic resonance (1H, 13C NMR) spectra were recorded on a Bruker
AM-500 spectrometer in CDCl3 or DMSO-d6, with TMS as internal standard. Fourier
transform infrared (FTIR) spectra were performed using Thermo Nicolet 6700
spectrophotometer in KBr pellets. The high-resolution mass spectra were recorded on
a Bruker microTOF-Q II and melting points (m.p.) were recorded on a X-4 electro
-thermal digital melting point apparatus. All of the chemicals used in the current study
were purchased from commercial vendors and used as received without further
purification, unless otherwise noted. All solvents were purified and dried using
standard methods prior to use.
4.2. Absorbance, emission and quantum yield
UV-Vis absorption spectra were measured on a UV-2550 and fluorescence spectra
were obtained with a F-7000 Fluorescence spectrophotometer. The solvents used in
the photochemical measurements were spectroscopic grade. All the experiments were
performed repeatedly, and reproducible results were obtained. The ΦF values in
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solution were measured following a general method with quinine sulfate (Φ = 0.55 in
50 mM H2SO4 solution) as a standard and dilute solutions of the compounds in
organic solvent were used (3×10-6 mol·L-1). The fluorescence spectra were recorded 3
times and the average values of the integrated areas of fluorescence were used to
calculate ΦF in solution. The solid emission spectra were measured by attaching the
solid samples on a support on F-7000 Fluorescence spectrophotometer.
4.3. Theoretical calculations
Density functional theory (DFT) with B3LYP functional and 6-31G basis set have
been used to optimize all the structure. For the fluorescence emission wavelength and
the excitation wavelength of the compounds was investigated using time-dependent
density functional theory (TDDFT). All these calculations were performed with the
Gaussian 09W program package. [23]
4.4. Preparation of compounds 1a-1b
A stirring mixture of benzoic acid (0.2442 g, 2.0 mmol), thiosemicarbazide
(0.1823 g, 2.0 mmol) and POCl3 (1.2 ml) was heated at 80 oC for 2.5 h. After cooling
down to room temperature, water (2.5 mL) was added. The reaction mixture was
refluxed for 4 h. After cooling, the mixture was basified to pH 8 by the dropwise
addition of 40% NaOH solution under stirring. The precipitate was filtered and
recrystallized from ethanol to yield 0.3130 g of the target compound 1a as a white
solid ,Yield: 88.3%.
4.4.1. 5-phenyl-1, 3, 4-thiadiazol-2-amine (compound 1a)
1
White solid. Yield 88.3%. M.p. 224-226 (ref: 223 ). H NMR (500 MHz,
CDCl3):δ 7.82 (dd, J = 6.5, 3.1 Hz, 2H), 7.45 (dd, J = 5.0, 1.8 Hz, 3H), 5.21 (bs, 2H).
4.4.2. 5-(4-methoxyphenyl)-1, 3, 4-thiadiazol-2-amine (compound 1b)
1
White solid. Yield 86.4%. M.p. 185-187 (ref: 181 ) . H NMR (500 MHz,
DMSO-d6): δ 7.69 (d, J = 8.6 Hz, 2H), 7.30 (s, 2H), 7.02 (d, J = 8.6 Hz, 2H), 3.80 (s,
3H).
4.5. Preparation of complexes 2a-2d
A stirring solution of 5-phenyl-1, 3, 4-thiadiazol-2-amine (1a) (0.3544 g, 2.0
mmol) and 4-dimethylaminopyridine (DMAP) (0.0122 g, 0.1 mmol) in THF (30 mL)
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at room temperature was treated with triethylamine (0.2021 g, 2.0 mmol). A solution
of benzoyl chloride (0.3373 g, 2.4 mmol) in THF (10 mL) was added dropwise to the
above mixture, and stirred for a further 6 h. The complete reaction was detected by
TLC analysis. The reaction mixture was added 30% aq Na2CO3 (5 mL) and stirred for
further 10 min, and then water (150 mL) was added. The precipitate was filtered and
recrystallized from ethanol to yield 0.4861 g of the target compound 2a as a white
solid ,Yield: 86.4 %.
4.5.1. N-(5-phenyl-1 ,3, 4-thiadiazol-2-yl)benzamide(compound 2a)
1
White solid. Yield 86.4%. M.p. 234-235 (ref: 237-238 ). H NMR (500 MHz,
CDCl3):δ 12.08 (bs, 1H), 8.30-8.28 (m, 2H), 7.99 (dd, J = 6.5, 3.1 Hz, 2H), 7.70 (t, J
= 7.4 Hz, 1H), 7.60 (t, J = 7.7 Hz, 2H), 7.54-7.51 (m, 3H).
4.5.2. 4-methoxy-N-(5-phenyl-1, 3, 4-thiadiazol-2-yl)benzamide (compound 2b)
1
White solid. Yield 84.3%. M.p. 249-251 (ref: 245 ) . H NMR (500 MHz,
DMSO-d6):δ 13.00 (bs, 1H), 8.17 (d, J = 8.7 Hz, 2H), 8.03-7.94 (m, 2H), 7.55 (d, J =
5.7 Hz, 3H), 7.11 (d, J = 8.7 Hz, 2H), 3.87 (s, 3H).
4.5.3. 4-nitro-N-(5-phenyl-1, 3, 4-thiadiazol-2-yl)benzamide (compound 2c)
1
Yellow solid. Yield 83.1%. M.p.ꢀ300℃ (ref: 271℃). H NMR (500 MHz,
DMSO-d6): δ 13.65 (bs, 1H), 8.38 (dd, J = 17.1, 8.4 Hz, 4H), 8.00 (d, J = 5.4 Hz, 2H),
7.56 (d, J = 5.3 Hz, 3H).
4.5.4. N-(5-(4-methoxyphenyl)-1, 3, 4-thiadiazol-2-yl)benzamide (compound 2d)
1
Yellow solid. Yield 85.5%. M.p. 230-232℃. H NMR (500 MHz, DMSO-d6):δ
13.09 (bs, 1H), 8.15 (d, J = 7.5 Hz, 2H), 7.93 (d, J = 8.7 Hz, 2H), 7.68 (t, J = 7.3 Hz,
1H), 7.58 (t, J = 7.6 Hz, 2H), 7.11 (d, J = 8.7 Hz, 2H), 3.85 (s, 3H).
4.6. Preparation of complexes 3a-3d
A stirring solution of 2a (0.1406 g, 0.5 mmol) in anhydrous toluene (25 mL),
Et3N (3 mL, 20 mmol) was syringed under nitrogen atmosphere. After stirred for 20
min, BF3·OEt2 (1.5 mL, 12 mmol) was injected. The mixture was stirred at 100°C
overnight and complete reaction was detected by TLC. The mixture was quenched
with water (20 mL), and extracted with ethyl acetate (3×25 mL). The combined
organic layer was dried with Na2SO4 and the solvent was removed under reduced
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pressure. The residue was purified by silica gel chromatography eluting (silica gel,
dichloromethane: petroleum ether=1: 1) to afford clean BF2 complex 3a as a white
solid 0.1203g,Yield 73.7%.
4.6.1.1,1-difluoro-3,6-diphenyl-1H-[1,3,4]thiadiazolo[3,2-c][1,3,5,2]oxadiazaborinin
-8-ium-1-uide (compound 3a)
White solid. Yield 73.7%. M.p. 220-222 . IR (KBr, cm-1): 1597, 1505, 1492,
1463, 1398, 1177, 1072, 824, 735, 723 cm-1. 1H NMR (500 MHz, CDCl3): δ
8.40-8.35 (m, 2H), 7.97-7.93 (m, 2H), 7.67 (dd, J = 10.6, 4.3 Hz, 1H), 7.63-7.59 (m,
1H), 7.54 (dd, J = 15.1, 7.8 Hz, 4H). 13C NMR (126 MHz, CDCl3): δ 174.42, 168.86,
162.89, 134.64, 132.70, 130.76, 130.57 (2C), 129.52 (2C), 128.74 (2C), 128.28,
127.53 (2C). HRMS m/z (ESI+): Calculated for C15H10N3OSBF2 ([M+H]+): 330.0684,
Found 330.0684.
4.6.2.1,1-difluoro-3-(4-methoxyphenyl)-6-phenyl-1H-[1,3,4]thiadiazolo[3,2-c][1,3,5,
2]oxadiazaborinin-8-ium-1-uide (compound 3b)
Yellowish solid. Yield 72.6%. M.p. 238-240 . IR (KBr, cm-1): 2848, 1603, 1580,
1
1471, 1395, 1267, 1162, 1068, 829, 765 cm-1. H NMR (500 MHz, CDCl3): δ
8.36-8.31 (m, 2H), 7.96-7.91 (m, 2H), 7.62-7.57 (m, 1H), 7.54 (t, J = 7.4 Hz, 2H),
7.03-6.99 (m, 2H), 3.93 (s, 3H). 13C NMR (126 MHz, CDCl3): δ 174.42, 168.53,
165.22, 162.09, 133.09 (2C), 132.53, 129.49 (2C), 128.50, 127.51 (2C), 123.03,
114.25 (2C), 55.68. HRMS m/z (ESI+): Calculated for C16H12N3O2SBF2 ([M+H]+):
360.0790, Found 360.0782.
4.6.3.1,1-difluoro-3-(4-nitrophenyl)-6-phenyl-1H-[1,3,4]thiadiazolo[3,2-c][1,3,5,2]ox
adiazaborinin-8-ium-1-uide (compound 3c)
Yellow solid. Yield 53.2%. M.p. 258-260 . IR (KBr, cm-1): 1537, 1508, 1460,
1406, 1345, 1191, 1082, 823, 773 cm-1. 1H NMR (500 MHz, CDCl3): δ 8.58-8.54 (m,
2H), 8.41-8.35 (m, 2H), 7.97 (dd, J = 5.2, 3.3 Hz, 2H), 7.67-7.63 (m, 1H), 7.61-7.56
(m, 2H). 13C NMR (126 MHz, Pyr): δ 174.56, 169.68, 166.41, 164.95, 151.39, 136.53,
133.05, 131.47, 131.12, 129.76, 129.27, 128.35, 127.92, 127.04, 123.99. HRMS m/z
(ESI+): Calculated for C15H9N4O3SBF2 ([M+H]+): 375.0535, Found 375.0532.
4.6.4.1,1-difluoro-6-(4-methoxyphenyl)-3-phenyl-1H-[1,3,4]thiadiazolo[3,2-c][1,3,5,
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2]oxadiazaborinin-8-ium-1-uide (compound 3d)
Green solid. Yield 40.9%. M.p. 256-258 . IR (KBr, cm-1): 2837, 1612, 1579,
1495, 1455, 1392, 1255, 1178, 1033, 992, 830, 721 cm-1. 1H NMR (500 MHz, CDCl3):
δ 8.37 (d, J = 7.0 Hz, 2H), 7.89 (d, J = 7.8 Hz, 2H), 7.71-7.63 (m, 1H), 7.58 -7.49 (m,
2H), 7.04 (d, J = 7.7 Hz, 2H), 3.92 (s, 3H). 13C NMR (126 MHz, Pyr): δ 174.41,
163.47, 134.76, 131.24, 130.56 (2C), 129.63 (2C), 129.08 (2C), 121.01, 115.24 (2C),
55.57. HRMS m/z (ESI+): Calculated for C16H12N3O2SBF2 ([M+H]+): 360.0790,
Found 360.0790.
Acknowledgments
We gratefully acknowledge the financial supported by the Natural Science
Foundation of China (21176223) and the National Natural Science Foundation of
Zhejiang (LY13B020016) and the Key Innovation Team of Science and Technology in
Zhejiang Province (2010R50018) and the Natural Science Foundation of China
(B060702).
References
1.Osmialowski, B.; Zakrzewska, A.; Jedrzejewska, B.; Grabarz, A.; etal. J. Org. Chem.2015, 80,
2072-2080.
2.Zhou, Y.; Xiao, Y.; Li, D.; Fu, M.Y.; Qian, X.H. J. Org. Chem.2008,73,1571-1574.
3.Wang, D.F.; Liu, R.; Chen, C.; Wang, S.F.; Chang, J.; Wu, C.H. Dyes Pigm. 2013, 99, 240-249.
4.Cao, Q.; Xiao, S.Z.; Mao, M.F.; Chen, X.H.; Wang, S.; Li, L. J. Organomet Chem. 2012,
717,147-151.
5.Olivier, J.H.; Camerel, F.; Ulrich, G.; Barbera, J.; Ziessel, R. Chem. Eur. J. 2010,16,7134-7142.
6.Osken, I.; Gundogan, A.S.; Tekin, E.; Eroglu, M.S.; Ozturk, T. Macromolecules
2013,46,9202-9210.
7.Rousseau, T.; Cravino, A.; Bura, T.; Ulrich, G.; Ziessel, R.; Roncali, J. Chem. Commun.
2009,13,1673-5.
8. Zheng, J.; Huang, F.; Li, Y.J.; Xu, T.W.; Xu, H.; Ye, Q. Dyes Pigm. 2015 ,113,502-509.
9.Jokic, T.; Borisov, S.M.; Saf, R.; Nielsen, D.A.; Kuhl, M.; Klimant, I. Anal. Chem.
2012,84,6723-6730.
10. Banuelos, J.; Mart í n, V.; Gomez-Duran, C.F.A.; Cordoba, I.J.A.; Pena-Cabrera, E.;
13

ACCEPTED MANUSCRIPT
García-Moreno, I. Chem. Eur. J. 2011,17,7261-70.
11.Coelho, P.J.; Castro, M.C.R.; Fernandes, S.S.M.; Fonseca, A.M.C.; Raposo, M.M.M.
Tetrahedron Lett. 2012,53,4502-4506.
12. Kaur, P.; Sareen, D.; Singh, K. Dalton Transactions 2012,41, 8767-8769.
13. Raposo, M.M.M.; Castro, M.C.R.; Fonseca, A.M.C.; Schellenberg, P.B.M.Tetrahedron
2011,67,5189-5198.
14.Kubota, Y.; Tsuzuki, T.; Funabiki, K.; Ebihara, M.; Matsui, M. Org. Lett. 2010,12,4010-4013.
15.Park, S.Y.; Ebihara, M.; Kubota, Y.; Funabiki, K.; Matsui, M. Dyes Pigm. 2009,82,258-67.
16. Babel, A.; Jenekhe, S.A. Adv. Mater. 2002,14,371-374;
17.Toal, S.J.; Jones, K.A.; Magde, D.; Trogler, W.C. J. Am .Chem. Soc. 2005,127,11661-11665.
18. Kubota, Y.; Hara, H.; Tanaka, S.; Funabiki, K.; Matsui, M. Org. Lett. 2011,13,6544-6547.
19. Zhao, Z.J.; Chen, S.M.; Shen, X.Y.; Mahtab, F.; Yu, Y.; Tang, B.Z. Chem. Commun.
2010,46,686-688.
20.Luo, J.; Xie, Z.; Lam, J.W.Y.; Cheng, L.; Tang, B.Z.; Chen, H. Chem. Commun.
2001,1740-1741.
21. Li, Z.; Dong, Y.Q.; Mi, B.X.; Tang, Y.H.; Tong, H.; Tang, B.Z. J. Phys. Chem. B
2005,109,10061-10066.
22.Tong, H.; Hong, Y.N.; Dong, Y.Q.; Haußler, M.; Lam, J.W.YL.; Tang, B.Z. Chem. Commun.
2006,35,3705-7.
23. Babür, B.; Seferoğlu, N.; Seferoğlu, Z. Tetrahedron Lett. 2015,56,2149-2154.
24.Hur, Y.; Kim, D.H.; Kim, E.K.; Park, J.H.; Joo, J.E.; Kang, H.W. PCT Int appl
2013,28,2013043001.
25.Li, H.; Chi, Z.; Zhang, X.; Xu, B.; Liu, S.; Zhang, Y. Chem. Commun. 2011,47,11273-11275.
26.Kubota, Y.;Tsuzuki, T.; Funabiki, K.; Ebihara, M.; Matsui, M. Org. Lett. 2010,12,4010-4013.
27.Wu, Y.Y.; Chen, Y.; Gou, G.Z.; Mu, W.H.; Lv, X.J.; Du, M.L. Org. Lett .2012,14,5226-5229.
28.Ooyama, Y.; Nabeshima, S.; Mamura, T.; Ooyama, H.E.; Yoshida, K. Tetrahedron
2010,66,7954-7960.
29.Ma, R.Z.; Yao, Q.C.; Yang, X.; Xia, M. J. Fluorine. Chem. 2012,137,93-98.
30.Li, X.; Son, Y.A. Dyes Pigm. 2014,107,182-187.
31.Kubota, Y.; Ozaki, Y.; Funabiki, K.;Matsui, M. J. Org. Chem. 2013,78, 7058-7067.
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