Macromolecules, Vol. 37, No. 4, 2004
Poly[di(1-naphthyl)-4-tolylamine] 1205
Di(1-n a p h th yl)-4-tolyla m in e (DNTA). To a three-necked
flask equipped with a reflux condenser, 1-bromonaphthalene
(6.83 g, 33 mmol), p-toluidine (1.6 g, 15 mmol), Pd2(dba)3 (0.34
g, 0.33 mmol), P(t-Bu)3 (0.357 g, 1.32 mmol), t-BuONa (4.44 g,
46.2 mmol), and toluene (30 mL) were added and stirred at
80 °C until p-toluidine disappeared in TLC analysis. The
precipitate was removed, and the filtrate was concentrated on
a rotary evaporator. The residue was extracted with ethyl
acetate, and the organic layer was washed with brine. This
was dried over MgSO4, concentrated under reduced pressure,
and purified by silica gel column chromatography using a
mixture of dichloromethane and hexane (1:1 in volume) as an
eluent to give a brown solid. The product was recrystallized
from a methanol-isopropyl alcohol (1:3 in volume) mixture,
affording a white solid. Yield was 4.1 g (76%); mp ) 155-157
°C.
IR (KBr) ν: 3046 (Ar C-H), 2915, 2857 (C-H), 1592, 1569,
1504 (CdC), 1392 (C-N), 779 cm-1 (naphthalene-H). 1H NMR
(300 MHz CDCl3) δ: 8.03 (d, 2H), 7.86 (d, 2H), 7.66 (d, 2H),
7.43 (t, 2H), 7.33 (t, 4H), 7.17 (d, 2H), 6.93 (d, 2H), 6.65 (d,
2H), 2.25 (s, 3H). 13C NMR (75 MHz, CDCl3) δ: 148.26, 145.29,
135.27, 130.27, 130.12, 129.53, 128.36, 126.05, 126.01, 125.90,
125.21, 124.43, 124.33, 121.03 (ArC), and 20.70 (CH3). Anal.
Calcd for C27H21N: C, 90.21%; H, 5.89%; N, 3.90%. Found: C,
90.35%; H, 6.05%; N, 3.62%.
F igu r e 1. 1H NMR spectrum of DNTA in CDCl3.
Sch em e 1. Syn th esis of DNTA
P olym er Syn th esis. A typical example of the polymeriza-
tion is as follows: In a 50 mL round-bottomed flask fitted with
a three-way stopcock were placed DNTA (0.178 g, 0.5 mmol),
FeCl3 (0.202 g, 1.25 mmol), and nitrobenzene (1 mL) under
nitrogen. The solution was stirred at room temperature for
24 h and poured into a mixture of methanol containing 10%
hydrochloric acid. The precipitate was collected, washed with
aqueous ammonium hydroxide, dissolved in chloroform, and
filtered. The filtrate was poured into methanol to precipitate
the polymer. This was dried in vacuo at 100 °C for 24 h. Yield
was 0.147 g (83%).
the residual chloroform. Then, tris(8-quinolinolato)aluminum-
(III) (Alq) was deposited onto the surface of the polymer films.
The film thickness was measured by using a DEKTAK3ST.
The Al cathode (1500 Å) with ultrathin LiF layer (5 Å) was
vapor deposited using a SOLCIET apparatus. The measure-
ments were made at room temperature under air. The EL
property was measured using a MCPD-7000 fluorescence
spectrophotometer by blocking the incident light.
IR (KBr) ν: 3066, 3039 (Ar C-H), 2919, 2857 (C-H), 1612,
1577, 1504 (CdC), 1376 (C-N), 759 cm-1 (naphthalene-H). 1H
NMR (300 MHz, CDCl3) δ: 8.30-8.20 (m, 2H), 7.56-7.26 (m,
10H), 7.04-6.93 (m, 2H), 6.87-6.81 (m, 2H), 2.27 (s, 3H). 13C
NMR (75 MHz, CDCl3) δ: 148.41, 144.94, 135.64, 134.59,
130.33, 130.20, 129.68, 128.36, 127.27, 126.00, 125.96, 124.72,
124.29, 121.06 (ArC), and 20.70 (CH3). Anal. Calcd for
(C27H19N)n: C, 90.73%; H, 5.35%; N, 3.92%. Found: C, 90.56%;
H, 5.80%; N, 3.63%.
Mea su r em en t. FT-IR spectra were measured on a Horiba
FT-720 spectrophotometer. NMR spectra were recorded on a
Bruker DPX-300 spectrometer. Number- and weight-average
molecular weights were measured by a gel permeation chro-
matography on a J asco Gulliver 1500 system equipped with a
polystyrene gel column (Plgel 5 µm Mixed-C) eluted with
CHCl3 at a flow rate of 1.0 mL/min calibrated by polystyrene
standard. The cyclic voltammograms were measured at room
temperature in a typical three electrode with a working (Pt
wire), a reference (Ag/AgCl), and a counter electrode (Pt spiral)
under a nitrogen atmosphere at a sweeping rate of 10 mV/s
(Hokuto Denko HSV-100). A 0.1 M solution of tetrabutylam-
monium perchlorate (TBAP) in anhydrous acetonitrile was
used as an electrolyte. Thermal analysis was performed on a
Seiko EXSTAR 6000 TG/DTA 6300 thermal analyzer at a
heating rate of 10 °C/min for thermogravimetry (TG) and a
Seiko EXSTAR 6000 DSC 6200 at a heating rate of 10 °C/min
for differential scanning calorimetry (DSC) under nitrogen.
The electron affinity was measured by combination of photo-
electron spectrometer (Riken Keiki, AC-1) and UV-vis absorp-
tion spectroscopy.
Resu lts a n d Discu ssion
Syn th esis of DNTA. The synthetic route for DNTA
is outlined in Scheme 1. DNTA was obtained by the
palladium-catalyzed N-arylation reaction of p-toluidine
with 2 equiv of 1-bromonaphthalene. The product was
purified by silica gel column chromatography, followed
by recrystallization from a methanol-isopropyl alcohol
mixture to give a white solid. The structure of DNTA
was assigned on the basis of elemental analysis as well
as IR and NMR spectroscopy. The IR spectrum of DNTA
showed characteristic absorptions corresponding to the
carbon-carbon double bond of the aromatic rings at
1592, 1569, and 1504 cm-1, and no bands at around
3420 and 3340 cm-1 due to the NH2 stretching of
1
p-toluidine were observed. Figure 1 shows the H NMR
spectrum of DNTA, consisting of one singlet at 2.25 ppm
and multiplets at 6.65-8.03 ppm that are assigned to
the methyl and aromatic protons, respectively. Further-
more, the structure of DNTA was confirmed by elemen-
tal analysis.
A full assignment of the aromatic protons was re-
quired to determine the coupling position between
naphthyl units. Figure 2 shows the H-H COSY spec-
trum for the aromatic region of DNTA. Aromatic signals
at 6.65 and 6.93 ppm are connected with a singlet signal
at 2.25 ppm. These signals can be assigned to the
aromatic protons of the tolylamino unit. In the spectrum
of 1-aminonaphthalene (Figure 3), the aromatic protons
at the 8- and 5-positions appear at the most downfield
(7.77 ppm) and at the second downfield (7.75 ppm),
respectively.19 In contrast, the aromatic proton at the
2-position is observed the most upfield (6.71 ppm).
Accordingly, the resonances at 8.03 and 7.86 ppm of
DNTA are assigned to the protons on position-l and -i,
Device F a br ica tion a n d Ch a r a cter iza tion . ITO-coated
glass with a sheet resistance 14 Ω/0 was patterned by aqua
regia. The patterned ITO-coated glass was cleaned by sequen-
tial ultrasonication in acetone, detergent, and 2-propanol for
10 min. Oxygen plasma cleaning was performed before use.
The OLED device was first spin-cast on a 2.5 × 2.5 cm ITO
glass from the polymer solution in chloroform. The spin-coated
polymer layer was annealed under reduced pressure at 100
°C for 2 h and dried at room temperature for 24 h to remove