42
T. Yu et al. / Organic Electronics 11 (2010) 41–49
N
N
N
CHO
N
N
OH
N
N
N
O
N
O
CN
N
DABTC-1
ClCH2CN
1
N
CHO
OH
N
H
TEA, DMF
110 oC
N
N
N
CN
N
N
N
O
N
O
2
DABTC-2
Scheme 1. Synthetic routes of 7-N,N-diethylamino-3-(benzotriazol-1-yl)coumarin and 7-N,N-diethylamino-3-(benzotriazol-2-yl)coumarin.
solutions and thin films were investigated in detail. We
fabricated the electroluminescence devices by vacuum
vapor-deposited film with doped with the compounds as
emission materials and investigated the electrolumines-
cent properties.
at reflux in the presence of triethylamine according to
the method reported by Sanna et al. [24].
2.2.2. 7-N,N-diethylamino-3-(benzotriazol-1-yl)coumarin
(DABTC-1)
1.93 g (10 mmol) of 4-(N,N0-diethylamino) salicylalde-
hyde, 1.67 g (10.6 mmol) 2-(1H-benzotriazol-1-yl)acetoni-
trile (1) were dissolved in 16 mL of anhydrous alcohol and
treated with piperidine (0.6 mL). The reaction mixture was
refluxed with stirring for 49 h, treated with HCl (3.5%), and
boiled for 5 h. After the reaction was finished, the resulting
mixture was poured into 50 mL of water and extracted
with dichloromethane (3 ꢁ 50 mL). The organic phase
was washed with water (2 ꢁ 50 mL) and dried over anhy-
drous MgSO4. After filtering, the filtrate was evaporated
to dryness under reduced pressure. The crude was purified
by chromatography on silica gel using ethyl acetate/petro-
leum ether (1:6, v/v) as the eluent to give 7-N,N-diethyl-
amino-3-(benzotriazol-1-yl)coumarin (DABTC-1) (1.12 g,
33.5%). m.p. 164–165 °C. 1H NMR: (500 MHz, CDCl3, d,
ppm): 8.116 (d, J = 4.8 Hz, 1H, Aryl-H), 8.049 (s, 1H, 4-H),
7.619–7.594 (m, 1H, Aryl-H), 7.565–7.554 (m, 1H, Aryl-
H), 7.540–7.516 (m, 1H, Aryl-H), 7.434–7.388 (m, 1H,
Aryl-H), 6.678 (d, J = 7.9 Hz, 1H, Aryl-H), 6.608 (s, 1H,
Aryl-H), 3.503–3.451 (m, 4H, –CH2–), 1.261 (t, J = 6.4 Hz,
6H, –CH3). IR (KBr pellet cmꢀ1): 3060 (Aryl-CH), 2971,
2929, 2891 (Alkyl-CH), 1728 (C@O, lactone), 1628 (C@C),
1590, 1524, 1421, 1250, 1121, 752. Anal. Calc. for
C19H18O2N4 (%): C, 68.25; H, 5.43; N, 16.76. Found: C,
68.53; H, 5.57; N, 16.84.
2. Experimental details
2.1. Materials and methods
4-(N,N0-diethylamino) salicylaldehyde from Zhejiang
Huadee Dyestuff Chemical Co. Ltd. (China) was recrystal-
lized from ethanol. 1H-benzotriazole (BTA) from Aldrich
was used without further purification. Triethylamine,
piperidine and chloroacetonitrile were analytical grade
reagents from Tanjin Fuchen Chemical Reagent Factory.
4,40-bis(9-carbazolyl) biphenyl (CBP), 2-(4-biphenylyl)-5-
(4-tert-butylphenyl)-1,3,4-oxadiazole (Bu-PBD), 4,40,400-
tris-N-naphthyl-N-phenylamino-triphenylamine (2-TNAT-
A) and N,N0-bis-(naphthyl)-N,N0-diphenyl-1,10-biphenyl-
4,40-diamine (NPB) were purchased from Electro-Light
Technology Corp., Beijing. The other solvents were analyt-
ical grade reagents.
IR spectra (400–4000 cmꢀ1) were measured on a Shima-
dzu IRPrestige-21 FT-IR spectrophotometer. 1H NMR spec-
tra were obtained on Unity Varian-500 MHz. C, H, and N
analyses were obtained using an Elemental Vario-EL auto-
matic elemental analysis instrument. Melting points were
measured by using an X-4 microscopic melting point appa-
ratus made in Beijing Taike Instrument Limited Company,
and the thermometer was uncorrected. UV–vis absorption
and photoluminescent spectra were recorded on a Shima-
dzu UV-2550 spectrometer and on a Perkin–Elmer LS-55
spectrometer, respectively. The electroluminescent spectra
were measured on a Hitachi MPF-4 spectrometer.
2.2.3. 7-N,N-diethylamino-3-(benzotriazol-2-yl)coumarin
(DABTC-2)
0.49 g (2.53 mmol) of 4-(N,N0-diethylamino) salicylal-
dehyde, 0.40 g (2.53 mmol) 2-(1H-benzotriazol-2-yl)aceto-
nitrile (2) were dissolved in 12 mL of absolute alcohol, and
then piperidine (0.2 mL) was dropped under ice bath. The
mixture was stirred for 12 h at room temperature, treated
with HCl (3.5%) and boiled for 5 h. After the reaction was
finished, the resulting mixture was poured into 20 mL of
water and extracted with dichloromethane (3 ꢁ 20 mL).
The organic phase was washed with water and dried over
anhydrous MgSO4. After filtering, the filtrate was evapo-
rated to dryness under reduced pressure. The crude was
purified by chromatography on silica gel using ethyl ace-
tate/petroleum ether (1:6, v/v) as the eluent to give 7-
2.2. Synthesis and characterization of 7-N,N-diethylamino-3-
(benzotriazol-1-yl)coumarin (DABTC-1) and 7-N,N-
diethylamino-3-(benzotriazol-2-yl)coumarin (DABTC-2)
The synthetic routes were shown in scheme 1.
2.2.1. 2-(1H-benzotriazol-1-yl)acetonitrile (1) and 2-(1H-
benzotriazol-2-yl)acetonitrile (2)
The intermediates 1 and 2 were synthesized by conden-
sation of 1H-benzotriazole with chloroacetonitrile in DMF