BULLETIN OF THE
Note
KOREAN CHEMICAL SOCIETY
were obtained with the addition of acetone. The resulting crys-
tals were filtered and then dried.
were sonicated for 5 min using an ultrasonic cleaner B5510
(Branson, MO, USA). The solutions were left to stand for
48 h at room temperature and then checked for precipitation
to determine the solubility of the dyes.
Measurement of Spectral Properties. The absorption spec-
tra of the synthesized colorants were measured using an HP
8452A spectrophotometer (Agilent, Santa Clara, CA, USA).
The fluorescence spectra of rhodamine B with synthesized
colorants were measured using a FluoroMate FS-2 fluores-
cence spectrophtometer (Scinco, Korea). The spectral overlap
integrals were calculated using the a|e’s Spectral Software
package (FluorTools, Sweden).
Measurement of Thermal Stability. The thermal stability of
the synthesized dyes was evaluated by thermogravimetry
(TGA). The prepared dyes were heated to 110 ꢀC and held
at that temperature for 10 min to remove the residual water
and solvents. The dye was then heated to 220 ꢀC and held at
that temperature for 30 min to simulate the thermal conditions
in the color filter manufacturing process. The dyes were then
heated to 400 ꢀC to determine their degradation temperature.
The heating was carried out at the rate of 10 ꢀC/min under
nitrogen atmosphere.
Preparation of Color Filters. Spin coating was carried out on
glass using a Spin-1200D (MIDAS SYSTEM, Korea). The
glasswas spun ata moderatespeed of 300 rpmfor10stospread
thesolutionevenly.Thesolutionwaspreparedwith2 gofcolor-
ants (C.I. Pigment Blue 15:6, rhodamine B, colorant = 86:6:8),
3.5 g of acrylic binder, 3.5 g of dipentaerythritol penta/hexaa-
crylate, 0.5 gofIngacure-369, and9.5 gofDAA.Whenthespin
coating was completed, the film was placed quickly on a hot-
plate (heated to around 100 ꢀC) for 5 min to evaporate the sol-
vent. It was then prebaked at 90 ꢀC for 90 s and post-baked at
220 ꢀC for 40 min. After each step, the transmittance spectra of
the colorant-coated glasses were measured.
Intermediates3and4weresynthesizedinthesamemanneras
intermediate 2b, except 1-bromopropane and (2-bromoethyl)
benzene, respectively, were used instead of 1-iodoethane.
Intermediate 2: Yield: 70%, 1H NMR (400 MHz, DMSO-
d6): 0.9 (s, CH3), 1.4 (m, CH2), 1.41 (t, CH3), 1.49 (s, CH3 ×
2), 7.30 (d, CH), 7.37 (t, CH), 8.02 (t, CH), 8.92 (d, CH), MS
(m/z) 315 (M+).
Intermediate 3: Yield: 74%, 1H NMR (400 MHZ, DMSO-
d6): 0.9 (s, CH3), 0.90 (t, CH3) 1.30 (t, CH2), 1.4 (m, CH2),
1.49 (s, CH3 × 2), 7.30 (d, CH), 7.37 (t, CH), 8.02 (t, CH),
8.92 (d, CH), MS (m/z) 282 (M+).
Intermediate 4: Yield: 72%, 1H NMR (400 MHz, DMSO-
d6): 0.9 (s, CH3), 1.49 (s, CH3 × 2), 1.7 (t, CH2), 2.6 (t, CH2),
7.27 (t, CH), 7.29 (d, CH × 2), 7.30 (d, CH), 7.37 (t, CH),
7.40 (t, CH × 2), 8.02 (t, CH), 8.92 (d, CH), MS (m/z) 344(M+).
Synthesis of 1-Ethyl-2-[3-(1-ethyl-3,3-dimethyl-1,3-dihy-
dro-indol-2-ylidene)-propenyl]-3,3-dimethyl-3H-indo-
lium Hexafluorophosphate (Colorant 2). Intermediate
2 (0.83 g, 2.62 mmol) was dissolved in pyridine (3 mL), fol-
lowed by the addition of triethyl orthoformate (0.4 g, 2.7
mmol). The mixture was heated to reflux for 24 h. Additional
triethyl orthoformate (0.4 g, 2.7 mmol) was added, and the
mixture continued to reflux for 24 h. After the reaction was ter-
minated, the mixture was cooled to room temperature. A 2.5%
solution of potassium hexafluorophosphate (20 mL) was then
added to the mixture. The mixture was stirred for 3 h. The
product was filtered and washed with n-hexane. The crude
product was purified by column chromatography (adsorbent:
silica gel, eluent: methanol/CH2Cl2).
Colorants 3 and 4 were synthesized in the same manner as
colorant 2 using intermediate 3 and intermediate 4, respec-
tively, instead of intermediate 2.
Colorant 2: Yield: 72%, 1H NMR (400 MHz, DMSO-d6):
1.31 (t, CH3), 1.4 (m, CH2), 1.41 (t, CH3), 1.49 (s, CH3 ×
2), 1.69 (s, CH3 × 2), 4.38 (m, CH2), 5.21 (d, H), 5.3 (d, H),
6.23 (d, CH), 6.5 (t, H), 6.69 (t, CH), 7.05 (t, CH), 7.08 (d,
CH), 7.30 (d, CH), 7.37 (t, CH), 8.02 (t, CH), 8.92 (d, CH),
MS (m/z) 530(100).
Acknowledgment. This work was supported by the Technol-
ogy Innovation Industrial Program funded By the Ministry of
Trade, Industry & Energy (MI, Korea).
Reference
Colorant 3: Yield: 68%, 1H NMR (400 MHZ, DMSO-d6):
0.90 (t, CH3 × 2), 1.3 (t, CH2), 1.4 (m, CH2), 1.49 (s, CH3 × 2),
1.69 (s, CH3 × 2), 1.70 (m, CH2), 4.07 (t, CH2), 5.21 (d, H), 5.3
(d, H), 6.23 (d, CH), 6.5 (t, H), 6.69 (t, CH), 7.05 (t, CH), 7.08
(d, CH), 7.30 (d, CH), 7.37 (t, CH), 8.02 (t, CH), 8.92 (d, CH),
MS (m/z) 558 (100).
1. V. Hall-Goulle, G. D. Keyzer, Y. Grndidier, US Patent July, 6,
2002, 2002/0014193.
2. J. Choi, S. H. Kim, W. Lee, C. Yoon, J. P. Kim, New J. Chem.
2012, 36, 812.
3. W. Lee, S. B. Yuk, D. H. Jung, S. H. Choi, J. Park, J. P. Kim, Dyes
Pigm. 2012, 92, 942.
4. J. Choi, C. Sakong, J. H. Choi, C. Yoon, J. P. Kim, Dyes Pigm.
2011, 90, 82.
5. R. Babu, A. Periasamy, J. Cell Biol. 2003, 160, 629.
6. S. Preus, L. M. Wilhelmsson, ChemBioChem 2012, 13, 1990.
7. B. Herman, In Methods in Cell Biology, Vol. 30, L. Taylor,
Y. L. Wang Eds., Academic Press, San Diego, CA, 1989, p. 233.
8. J. R. Lakowicz, Principle of Fluorescence Spectroscopy,
Springer, Baltimore, MD, 2006, p. 446.
1
Colorant 4: Yield: 62%, H NMR (400 MHz, DMSO-d6):
1.49 (s, CH3 × 2), 1.69 (s, CH3 × 2), 1.7 (t, CH2), 2.6 (t, CH2),
3.06 (t, CH2), 4.72 (t, CH2), 5.21 (d, H), 5.3 (d, H), 6.23 (d,
CH), 6.5 (t, H), 6.69 (t, CH), 7.05 (t, CH), 7.08 (d, CH), 7.27
(t, CH × 2), 7.29 (d, CH × 4), 7.30 (d, CH), 7.37 (t, CH), 7.40
(t, CH × 4), 8.02 (t, CH), 8.92 (d, CH), MS (m/z) 682(100).
Investigation of Solubility. The solubility of the synthesized
colorants was examined. The prepared dyes were added to
the solvents at various concentrations, and the solutions
9. S. Das, R. Baru, M. Minch, P. Nandy, Dyes Pigm. 1995, 29, 191.
Bull. Korean Chem. Soc. 2015, Vol. 36, 2545–2548
© 2015 Korean Chemical Society, Seoul & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim