TSAI ET AL.
5
for 13.5 hr and cooled to room temperature. It was added to
methanol in a beaker, and white solid was collected by fil-
tration. The white solid was dried, and the high purity com-
overnight. Another portion of N-bromosuccinimide (0.34 g,
1.9 mmol) was added and stirred for 3 hr. The solution was
extracted with distilled water (50 mL × 2) and saturated
NaCl solution (50 mL). The organic layer was dried over
filtered anhydrous MgSO4 . After removing the solvent, the
residue was purified by recrystallization in CH2Cl2/Hex-
1
pound 5 was collected (7.02 g, 90%). H NMR (300 MHz,
CDCl3) δ ppm: 3.63 (d, 4H), 1.83 (m, 2H), 1.32 (m, 16H),
0.92 (m, 12H); 13C NMR (75 MHz, CDCl3) δ ppm: 163.8,
136.2, 114.2, 42.9, 38.3, 30.6, 28.6, 23.9, 23.0, 14.1, 10.4.
1
anes. Yellow solid 8 (0.6 g, 90%) was obtained. H NMR
(300 MHz, CDCl3) δ ppm: 7.17 (d, 2H), 7.02 (d, 2H), 3.50
(d, 4H), 1.76 (m, 2H), 1.26 (m, 16H), 0.86 (m, 12H); 13C
NMR (75 MHz, CDCl3) δ ppm: 165.2, 135.3, 130.9, 130.1,
129.9, 128.3, 127.0, 42.8, 38.1, 30.6, 28.5, 24.0, 23.1, 14.1,
10.5. FITR (KBr, υ cm−1): 3154, 3048, 2982, 2304, 2253,
1793, 1717, 1644, 1603, 1555, 1467, 1421, 1381, 1264,
1166, 1095, 910, 728. HRMS: calcd. for C34H38Br2N2O4S2
760.0640; found 760.0635.
3.2.4
| Trimethyl(thiophen-2-yl)stannane (6)
Thiophene (15.1 g, 0.18 mol) was dissolved in ether
(100 mL) in a three-neck round-bottom flask and cooled to
0ꢀC. n-Butyllithium (72 mL, 0.18 mol) was added dropwise
to the thiophene solution until all n-butyllithium was used
up. The reaction was warmed to room temperature gradually
and stirred for 3 hr. Trimethyltin chloride (35.0 g in
100 mL ether, 17.6 mol) was added to the above solution
and stirred overnight. The reaction mixture was quenched
with distilled water (100 mL × 2) and filtered. Filtrate was
extracted with saturated NaCl solution (100 mL), and the
organic layer was dried over anhydrous MgSO4. After
removing the solvent, the residue was purified by flash col-
umn (silica gel, hexanes). Transparent liquid 6 (30.16 g,
3.2.7
|
5,50-Bis(trimethylstannyl)-2,20-bithiophene (9)
A solution of 202-bithiophene (1.0 g, 6.01 mmol) in dry
THF (50 mL) was cooled to −78ꢀC. n-BuLi (2.5 M in
THF, 13.3 mmol) was added dropwise and stirred at −78ꢀC
for 1.5 hr; 13.3 mL Trimethyltin chloride (1 M in THF,
13.3 mmol) was added slowly to the reaction solution and
stirred at room temperature overnight. Saturated NH4Cl(aq)
and ethyl acetate were mixed with the reaction solution.
The organic layer was washed with water and dried over
MgSO4(s). White solid was obtained after removing solvent
and recrystallized from methanol. White solid compound
1
68%) was obtained. H NMR (300 MHz, CDCl3) δ ppm:
7.65 (dd, 1H), 7.26 (dd, 1H), 7.22 (dd, 1H), 0.37 (s, 9H).
3.2.5
| 2,6-Bis(2-ethylhexyl)-4,8-di(thiophen-2-yl)pyrrolo[3,4-
f]isoindole-1,3,5,7(2H,6H)-tetraone (7)
Compound 5 (0.598 g, 1 mmol), trimethyl(thiophen-2-yl)
stannane (6) (0.755 g, 3.0 mmol), and tetrakis(triphenylpho-
sphine) palladium (231 mg, 10 mol%) were mixed with
15 mL anhydrous toluene and 3 mL dimethylformamide
under nitrogen in a three-necked round-bottom flask. The
1
9 was obtained. Yield: 1.5 g (51%). H NMR (300 MHz,
CDCl3) δ ppm: 7.28 (d, 2H), 7.08 (d, 2H), 0.38 (s, 18H).
3.2.8
|
5,50-Dibromo-2,20-bithiophene (10)
N-Bromosuccinimide (4.48 g, 25 mmol) was added slowly
at room temperature to a solution of 2,20-bithiophene (2.0 g,
12 mmol) in acetic acid (60 mL) and stirred overnight. The
reaction solution was poured into cold water (200 mL) and
filtered. The filtered solid was washed by distilled water
thoroughly and dried under reduced pressure. White solid
10 was collected (3.84 g, 99%). 1H NMR (300 MHz,
CDCl3) δ ppm: 6.96 (d, 2H), 6.85 (d, 2H).
ꢀ
solution was refluxed under nitrogen at 120 C for 18 hr
and poured into 100 mL water after cooling to room tem-
perature. It was extracted with CH2Cl2 (50 mL × 2). The
CH2Cl2 portion was extracted with distilled water
(100 mL × 2), saturated NaCl solution (100 mL), and dried
over anhydrous MgSO4(s) After removing solvent under
vacuum, the residue was purified by flash column (silica
gel, CH2Cl2:hexanes = 3:2) and recrystallized from
CH2Cl2/hexanes. The yellow solid 7 (0.528 g, 87%) was
3.2.9
|
3,3000-Dihexyl-2,20:50,200:500,2000-quaterthiophene (11)
1
obtained. H NMR (300 MHz, CDCl3) δ ppm: 7.65 (dd,
A total of 0.52 g magnesium (21.2 mmol) was added to a
250 -mL three-neck round-bottom flask containing 40 mL
dry ether and 0.3 mL 1,2-dibromoethane. The solution was
heated slowly until the reaction started; 2-Bromo-3-
hexylthiophene (3.72 mL, 18.7 mmol) was then added to
the reaction dropwise and refluxed for 2 h; 5,50-Dibromo-
2,20-bithiophene (2.63 g, 8 mmol) and [1,3-bis(diphenyl phos-
phino)-propane]dichloro- nickel(II) (65.2 mg, 0.12 mmol)
were added to the other three-neck round-bottom flask
containing toluene (60 mL) and ether (40 mL). The 3-
hexylthiophene Grignard reagent prepared from the first part
was added dropwise to the toluene/ether solution and refluxed
overnight. Additional ether and distilled water were added to
2H), 7.27 (m, 4H), 3.51 (d, 4H),1.79 (m, 2H), 1.28 (m,
16H), 0.87 (t, 12H); 13C NMR (75 MHz, CDCl3) δ ppm:
165.2, 135.3, 130.9, 130.1, 129.9, 128.3, 127.0, 42.7, 38.1,
30.6, 28.5, 24.0, 23.1, 14.1, 10.5.FTIR (KBr, υ cm−1):
3053, 2982, 2684, 2516, 2410, 2303, 1767, 1717, 1550,
1421, 1396, 1262, 1158, 895, 751, 723, 706. HRMS: calcd.
for C34H40N2O4S2 604.2429; found 604.2439.
3.2.6
| 4,8-Bis(5-bromothiophen-2-yl)-2,6-bis(2-ethylhexyl)
pyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetraone (8)
N-Bromosuccinimide (0.34 g, 1.9 mmol) was added to a
solution of 7 (0.528 g, 0.87 mmol) in acetic acid (25 mL)
and CH2Cl2 (10 mL) at room temperature and stirred