G Model
CCLET 3765 1–8
Y. Xie et al. / Chinese Chemical Letters xxx (2016) xxx–xxx
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and the AC amplitude was set to 10 mV. The bias of the EIS
measurements was set to VOC of the corresponding dye sensitizer.
Cyclic voltammetry was recorded with a computer-controlled
electrochemical analyzer (IviumStat, Holland) at a constant scan
rate of 100 mV sÀ1. Measurements were performed with a three-
electrode cell in 0.1 M Bu4NClO4-N,N-dimethylformamide solu-
tion, Pt wire as a counter electrode, and an Ag/AgCl reference
electrode; the measurements were then calibrated with ferrocene.
Synthesis of compound AFL1: 2a (0.54 g, 0.1 mmol) was mixed 173
with cyanoacetic acid (0.02 g, 0.23 mmol) in dry acetonitrile 174
(15 mL) and piperidine (0.1 mL). The solution was refluxed 175
overnight. The solvent was removed in vacuo. The pure product 176
AFL1 was obtained through column chromatography (silica gel, 177
CH2Cl2:CH3OH:HAc = 300:10:1). The following properties were 178
observed: yield, 45% (0.27 g). mp 206.8–208.6 8C. 1H NMR 179
[400 MHz, (CD3)2CO]:
d 7.96 (s, 1H), 7.94 (d, 2H, J = 4 Hz), 7.82- 180
7.72 (m, 5H), 7.68-7.65 (m, 4H), 7.53 (d, 1H, J = 4 Hz), 7.45 (t, 2H, 181
J = 8 Hz), 3.37-7.26 (m, 5H), 7.16 (q, 4H, J = 8 Hz and 16 Hz), 7.10- 182
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2.4. Detailed experimental procedures and characterization data
7.07 (m, 1H), 1.40(s, 6H); 13C NMR (125 MHz, CDCl3):
d 24.96, 183
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Synthesis of compound 2-amino-N-[(1,1’-biphenyl)-4-yl]-N-(4-
bromophenyl)-9,9-dimethylfluorene 1: A mixture of 1,4-dibro-
mobenzene (0.2 g, 0.8 mmol), 2-(4-biphenylyl)amino-9,9-
dimethylfluorene (0.36 g, 1 mmol), Pd(OAc)2 (0.046 g, 0.2 mmol),
P(t-Bu)3 (0.04 g, 0.2 mmol), and Cs2CO3 (1.63 g, 5 mmol) in dry
toluene (15 mL) was stirred and heated at 110 8C overnight. After
the mixture was cooled to room temperature, saturated ammoni-
um chloride solution was added to the reaction solution. The
solution was extracted with dichloromethane, dried with MgSO4,
and subjected to column chromatography (silica gel, dichloro-
methane/hexanes = 3:1). A yellow solid was obtained with the
following properties: yield, 57% (0.24 g); mp 160.1–161.5 8C; 1H
26.97, 46.72, 95.00, 107.47, 112.46, 114.61, 119.53, 119.53, 119.91, 184
121.58, 122.23, 122.91, 122.92, 122.98, 123.30, 123.31, 124.27, 185
124.30, 126.43, 126.44, 127.35, 127.95, 127.95, 127.99, 128.06, 186
129.16, 129.16, 130.29, 131.90, 134.81, 134.87, 138.32, 139.64, 187
141.77, 144.97, 145.03, 146.29, 146.61, 150.91, 153.49, 155.2À6, 188
165.70; HRMS: m/z calcd. for C43H31N2O2: 607.2453 [M-H]
;
189
190
Found: 607.2477.
Synthesis of compound AFL2: 2b (0.55 g, 0.1 mmol) was mixed 191
with cyanoacetic acid (0.02 g, 0.23 mmol) in dry acetonitrile 192
(15 mL) and piperidine (0.1 mL). The solution was refluxed 193
overnight. The solvent was removed in vacuo and the residue. 194
The pure product AFL2 was obtained through column chromatog- 195
raphy (silica gel, CH2Cl2:CH3OH:HAc = 300:10:1). Yield: 37% 196
NMR [400 MHz, (CD3)2CO]:
d 7.64 (d, J = 8 Hz, 1H), 7.60–7.57 (m,
3H), 7.50–7.48 (m, 2H), 7.43-7.40 (m, 2H), 7.38–7.26 (m, 5H), 7.25
(s, 1H), 7.20 (s, 1H), 7.17 (s, 1H), 7.15 (s, 1H), 7.06–7.02 (m, 3H),
1.42 (s, 6H). HRMS: m/z calcd. for C33 H26 Br N: 516.1321 [M-H]À;
Found: 516.1337.
Synthesis of compound 2a: A mixture of 1 (0.52 g, 0.1 mmol), 4-
formylphenylboronic acid (0.18 g, 0.12 mmol), Pd(PPh3)4 (0.14 g,
0.012 mmol), K2CO3 (0.14 g, 1 mmol), and degassed water (2 mol/
L) in dry THF (15 mL) was refluxed overnight. After the mixture
was cooled to room temperature, the solution was extracted with
dichloromethane, dried with MgSO4, and subjected to column
chromatography (silica gel, PE:EA = 5:1). A light yellow solid was
obtained. Yield: 68% (0.37 g). mp 95.9- 97.7 8C. 1H NMR [400 MHz,
(0.23 g). mp 207.9- 208.6 8C. 1H NMR (125 MHz, CDCl3):
d 7.65 197
(d, 1H, J = 8 Hz), 7.62(d, 1H, J = 8 Hz), 7.60-7.57 (m, 3H), 7.52 (d, 2H, 198
J = 8 Hz), 7.44-7.38 (m, 4H), 7.33-7.28 (m, 2H), 7.26 (m, 6H), 7.21 (s, 199
1H), 7.16 (s, 1 H), 7.13 (s, 1H), 7.11 (q, 1H, J = 4 Hz and 8 Hz), 1.43 (s, 200
6H); 13C NMR (100MHz, CDCl3):
d 24.90, 26.93, 46.84, 94.99, 201
108.85, 119.51, 119.57, 119.60, 119.89, 119.91, 119.96, 121.53, 202
121.57, 122.87, 122.90, 122.94, 122.96, 124.53, 124.66, 126.40, 203
126.40, 126.83, 127.16, 127.19, 127.21, 127.94, 127.96, 129.15, 204
129.15, 134.98, 135.56, 138.26, 139.26, 146.01, 146.31, 147.92, 205
148.54, 154.42, 153.49, 155.26, 164.20; HRMS: m/z calcd. for 206
C
41H29N2O2S: 607.2453 [M-H] À; Found: 607.2477.
Synthesis of compound AFL3: A mixture of 2c (0.55 g, 0.1 mmol) 208
207
(CD3)2CO]:
d
10.0 (s, 1H), 7.92 (d, 2H, J = 8 Hz), 7.75 (d, 2H, J = 8 Hz),
and cyanoacetic acid (0.02 g, 0.23 mmol) in dry acetonitrile 209
(15 mL) and piperidine (0.1 mL) was prepared. The solution was 210
refluxed overnight. The solvent was removed in vacuo and the 211
residue. Then, the pure product AFL3 was obtained through 212
7.64–7.52 (m, 7 H), 7.40 (q, 2H, J = 4 Hz and 12 Hz), 7.32–7.23 (m,
10H), 7.13–7.11 (m, 1H), 1.44 (s, 6H); HRMS: m/z calcd. for C40 H31
NO: 542.2478 [M-H] À; Found: 542.2488.
Synthesis of compound 2b: A mixture of 1 (0.52 g, 0.1 mmol), 5-
formylthiophene-2-boronic acid (0.19 g, 0.12 mmol), Pd(PPh3)4
(0.14 g, 0.012 mmol), K2CO3 (0.14 g, 1 mmol), and degassed water
(2 mol/L) in dry THF (15 mL) was refluxed overnight. After the
mixture was cooled to room temperature, the solution was
extracted with dichloromethane, dried with MgSO4, and subjected
to column chromatography (silica gel, PE:EA = 15:1). A yellow solid
was obtained. Yield: 49% (0.27 g). mp 102.8- 104.1 8C. 1H NMR
column
cOH = 400:20:1). Yield: 48% (0.28 g). mp 238.6- 240.18C. 1H 214
NMR (400 MHz, CDCl3): 7.66-7.64 (m, 2H), 7.63 (s, 2H), 7.60 215
chromatography
(silica
gel,
CH2Cl2:CH3OH:A- 213
d
(s, 2H), 7.58 (s, 1H), 7.52 (s, 1H), 7.50 (s, 1H), 7.44-7.38 (m, 4H), 216
7.33-7.26 (m, 3H), 7.22 (s, 1H), 7.20 (s, 1H), 7.18 (s, 1 H), 7.16 (s, 217
1H), 7.10 (d, 1H, J = 8 Hz), 7.02 (s, 1H), 6.76 (d, 1H, J = 4 Hz), 1.42 (s, 218
6H); 13C NMR (125 MHz, CDCl3):
d 22.99, 26.84, 46.57, 107.70, 219
107.90, 119.40, 119.47, 119.58, 119.85, 119.89, 121.44, 121.47, 220
121.48, 122.66, 122.82, 124.42, 124.42, 125.79, 125.81, 125.82, 221
126.34, 126.34, 127.06, 127.22, 127.23, 127.85, 127.87, 129.04, 222
129.04, 134.97, 135.07, 138.21, 139.56, 145.91, 146.20, 147.83, 223
148.36, 154.42, 155.20, 156.11, 162.47; HRMS: m/z calcd. for 224
[400 MHz, (CD3)2CO]: d 9.85 (s, 1H), 7.71 (d, 1H, J = 4 Hz), 7.67-7.53
(m, 7H), 7.43 (q, 3H, J = 4 Hz and 12 Hz), 7.34-7.22 (m, 8H), 7.17 (d,
2H, J = 8 Hz), 7.12 (d, 1H, J = 8 Hz), 1.45 (s, 6H); HRMS: m/z calcd.
for C38 H29 NOS: 548.2043 [M-H] À; Found: 548.2019.
Synthesis of compound 2c: A mixture of 1 (0.52 g, 0.1 mmol),
2-formylfuran-5-boronic acid (0.16 g, 0.12 mmol), Pd(PPh3)4
(0.14 g, 0.012 mmol), K2CO3 (0.14 g, 1 mmol), and degassed water
(2 mol/L) in dry THF (15 mL) was refluxed overnight. After the
mixture was cooled to room temperature, the solution was
extracted with dichloromethane, dried with MgSO4, and sub-
jected to column chromatography (silica gel, PE:EA = 3:1). A
yellow solid was obtained. Yield: 47% (0.25 g). mp 101.6- 102.5 8C.
C
41H29N2O3: 597.2184 [M-H] À; Found: 597.2209.
225
226
227
3. Results and discussion
3.1. Synthesis
Three novel triarylamine dye sensitizers consisting of cyanoa- 228
cetic acid as an electron acceptor and fluorenyl and biphenyl 229
moieties in the donor with various conjugated linkers were 230
prepared. The synthetic routes are shown in Scheme 1. In a typical 231
Ullmann reaction, 1 was obtained from 2-(4-biphenylyl) amino- 232
9,9-dimethylflu-orene and 1,4-dibromobenzene with a good yield. 233
Then, the following Suzuki coupling reaction between 1 and 234
arylboronic acids yielded the corresponding aldehydes 2a–2c. The 235
1H NMR [400 MHz, (CD3)2CO]:
d 9.59 (s, 1H), 7.69 (d, 4H, J = 8 Hz),
7.66 (d, 1H, J = 8 Hz), 7.61 (d, 2H, J = 8 Hz), 7.53 (d, 2H, J = 8 Hz),
7.42 (q, 2H, J = 8 Hz and 16 Hz), 7.34-7.22 (m, 7H), 7.19 (s, 1H),
7.16 (s, 1H), 7.11 (d, 1H, J = 8 Hz), 6.72 (d, 1H, J = 4 Hz), 1.43 (s, 6H);
HRMS: m/z calcd. for C38 H29NO2: 532.2271 [M-H] À; Found:
532.2278.
Please cite this article in press as: Y. Xie, et al., Novel organic dye sensitizers containing fluorenyl and biphenyl moieties for solar cells,