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(0.01 g, 0.03 mmol) dissolved in anhydrous toluene (20 mL) was
stirred in a two-necked flask under a nitrogen atmosphere. The
mixture was refluxed for 12 h. After cooling to room temperature,
the solution was filtered, and the filtered solution was extracted
with dichloromethane and distilled water. The organic layer was
dried over anhydrous MgSO4 and concentrated. The crude product
was purified by column chromatography using n-hexane/methyl-
ene chloride (1:10) to afford TrzIAc as a white powder (0.32 g,
Experimental Section
General information: General information about the analysis was
described in a previous work.[15]
Methyl-2-((9,9-dimethyl-9H-fluoren-2-yl)amino)benzoate:
2-
Bromo-9,9-dimethyl-9H-fluorene (5.0 g, 18.3 mmol), palladium(II)
acetate (0.08 g, 0.3 mmol), xantphos (0.4 g, 0.7 mmol) and cesium
carbonate (8.4 g, 25.6 mmol) in anhydrous toluene (60 mL) were
stirred in a two-necked flask under a nitrogen atmosphere. Next,
methyl 2-aminobenzoate (3.3 g, 21.9 mmol) was added dropwise
slowly to the mixture. The solution was then refluxed for 24 h.
After cooling to room temperature, the solution was extracted
with ethyl acetate and distilled water. The organic layer was dried
over anhydrous MgSO4 and evaporated using a rotary evaporator.
The resulting residue was purified by column chromatography
using n-hexane/ethyl acetate (1:8) to afford the title compound as
1
41%). H NMR (400 MHz, DMSO): d=1.23 (s, 6H), 1.75 (s, 6H), 6.32
(d, 1H, J=8.4 Hz), 6.46 (s, 1H), 6.96–7.05 (m, 2H), 7.19 (t, 1H, J=
7.2 Hz), 7.30 (t, 1H, J=7.2 Hz), 7.42 (d, 1H, J=8.0 Hz), 7.57 (d, 1H,
J=7.2 Hz), 7.67–7.77 (m, 8H), 7.84 (d, 1H, J=8.0 Hz), 8.01 (s, 1H),
8.81 (d, 4H, J=7.6 Hz), 9.08 (d, 2H, J=8.4 Hz). 13C NMR (100 MHz,
DMSO): d=27.4, 31.3, 36.6, 46.8, 108.8, 114.7, 116.8, 119.1, 121.2,
122.5, 125.3, 126.0, 126.5, 127.0, 128.9, 129.2, 129.9, 130.8, 131.4,
131.7, 132.5, 132.9, 136.1, 136.3, 139.7, 140.8, 141.0, 145.9, 152.5,
153.4, 171.3, 172.1 ppm.
1
a yellow powder (5.3 g, 84%). H NMR (400 MHz, DMSO): d=1.43
(s, 6H), 3.86 (s, 3H), 6.80 (t, 1H, J=7.6 Hz), 7.22–7.51 (m, 7H), 7.76
(m, 2H), 7.91 (d, 1H, J=3.8 Hz), 9.45 ppm (s, 1H).
Device fabrication and measurements: The device structure was
indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styre-
nesulfonate) (PEDOT:PSS, 60 nm)/4,4’-cyclohexylidenebis[N,N-bis(4-
methylphenyl)aniline] (TAPC, 30 nm)/mCP:TPBi:TrzIAc or TrzAc
(25 nm:50%:x%)/diphenyl(4-(triphenylsilyl)phenyl)phosphine oxide
(TSPO1, 5 nm)/TPBi (30 nm)/LiF (1.5 nm)/Al (200 nm). TrzIAc and
TrzAc were mixed with the mCP:TPBi (50:50) mixed host at doping
concentrations of 10, 20 and 30%. The device characterization
method was reported previously.[15]
7,7,13,13-Tetramethyl-7,13-dihydro-5H-indeno[1,2-b]acridine
(IAc):
Methyl
2-((9,9-dimethyl-9H-fluoren-2-yl)amino)benzoate
(2.5 g, 7.3 mmol) was dissolved in anhydrous THF (75 mL) under ni-
trogen at À788C and then a methyllithium solution in diethoxyme-
thane (0.8 g, 3.6 mmol) was added dropwise slowly. The solution
was stirred for 5 h at À408C. The mixture was gradually warmed to
room temperature, quenched with methanol, and extracted with
ethyl acetate and distilled water. The organic layer was dried over
anhydrous MgSO4 and concentrated. The crude powdery product
was used without further purification, and the crude product
(3.9 g, 11.3 mmol) was dissolved in methylene chloride (70 mL)
under nitrogen at À208C. The solution was stirred for 30 min, fol-
lowed by addition of a mixture of polyphosphoric acid (19.5 g,
102.2 mmol) and methanesulfonic acid (10.9 g, 113. 6 mmol). The
solution was quenched with 20% NaOH aqueous solution and ex-
tracted with ethyl acetate. The organic layer was dried over anhy-
drous MgSO4 and evaporated by using a rotary evaporator. The
residue was purified by column chromatography using n-hexane/
ethyl acetate (1:10) as an eluent to afford IAc as a white powder
(1.3 g, 55%). 1H NMR (400 MHz, DMSO): d=1.41 (s, 6H), 1.58 (s,
6H), 6.82 (t, 2H, J=7.2 Hz), 6.89 (s, 1H), 7.06 (t, 1H, J=8.8 Hz), 7.18
(t, 1H, J=7.2 Hz), 7.27 (t, 1H, J=7.2 Hz), 7.37 (d, 1H, J=7.6 Hz),
7.44 (d, 1H, J=7.6 Hz), 7.73 (d, 1H, J=7.6 Hz), 7.80 (s, 1H),
8.91 ppm (s, 1H).
Acknowledgements
This research was supported by Basic Science Research Re-
search Program through the National Research Foundation of
Korea (NRF) funded by Ministry of Science, ICT, and future Plan-
ning (2013R1A2A2A01067447) and development of red and
blue OLEDs with external quantum efficiency over 20% using
delayed fluorescent materials funded by MOTIE.
Keywords: acridine · donor–acceptor systems · high quantum
efficiency · photoluminescence · photophysics · TADF
2-(4-Bromophenyl)-4,6-diphenyl-1,3,5-triazine: A solution of 2-
chloro-4,6-diphenyl-1,3,5-triazine (3.0 g, 11.2 mmol), (4-bromo phe-
nyl)boronic acid (3.4 g, 16.8 mmol) and tetrakis(triphenylphophine)-
palladium(0) (0.6 g, 0.6 mmol) dissolved in THF (80 mL) was stirred
in a two-necked flask under a nitrogen atmosphere for 30 min. To
the above reaction mixture was added a solution of potassium car-
bonate (11.1 g) in distilled water (40 mL) dropwise over a period of
20 min. The resulting mixture was refluxed overnight at 808C and
extracted with methylene chloride and water. After evaporation of
the organic phase with a rotary evaporator, the resulting powder
was purified by column chromatography using n-hexane to afford
the title compound as a white powder (3.0 g, 69%). 1H NMR
(400 MHz, CDCl3): d=7.55–7.62 (m, 6H), 7.71 (d, 2H, J=8.8 Hz),
8.65 (d, 2H, J=10.8 Hz), 8.75–8.77 ppm (m, 4H).
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5-(4-(4,6-Diphenyl-1,3,5-triazine-2-yl)phenyl)-7,7,13,13-tetra-
methyl-7,13-dihydro-5H-indeno[1,2-b]acridine (TrzIAc): A solu-
tion of 7,7,13,13-tetramethyl-7,13-dihydro-5H-indeno[1,2-b]acridine
(0.4 g, 1.2 mmol), 2-(4-bromophenyl)-4,6-diphenyl-1,3,5-triazine
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