Synthesis of regio- and stereoselective alkoxy-substituted spirobifluorene derivatives for blue light emitting materials

Article abstract of DOI:10.1016/S0040-4020(03)00371-5

Three new octyloxy substituted spirobifluorenes, 2,7-diphenyl-3′,6′-bis(octyloxy)-9,9′-spirobifluorene (DPBSBF, 1a), 2,7-dibiphenyl-3′,6′-bis(octyloxy)-9,9′-spirobifluorene (DBBSBF, 1b) and 2,7-diterphenyl-3′,6′-bis(octyloxy)-9,9′-spirobifluorene (DTBSBF,

Full text of DOI:10.1016/S0040-4020(03)00371-5

Tetrahedron 59 (2003) 2773–2779
Synthesis of regio- and stereoselective alkoxy-substituted
spirobifluorene derivatives for blue light emitting materials
a
a
a
a
Hyoyoung Lee,a Jiyoung Oh, Hye Yong Chu, Jeong-Ik Lee, Seong Hyun Kim,
Yong Suk Yang,a Gi Heon Kim,a Lee-Mi Do,a Taehyoung Zyung,a Jouhahn Leeb
and Yongsup Parkb
,
*
aBasic Research Laboratory, ETRI, Taejon 305-350, South Korea
bNano-Surface Group, KRISS, P.O. Box 102, Yusong, Taejon 305-600, South Korea
Received 27 January 2003; revised 11 March 2003; accepted 11 March 2003
Abstract—T0hree new octyloxy substituted spirobifluorenes, 2,7-diphenyl-30,60-bis(octyloxy)-9,90-spirobifluorene (DPBSBF, 1a), 2,7-di-
biphenyl-30,6 -bis(octyloxy)-9,90-spirobifluorene (DBBSBF, 1b) and 2,7-diterphenyl-30,60-bis(octyloxy)-9,90-spirobifluorene (DTBSBF, 1c)
were prepared. All the compounds had been fully characterized by 1H and 13C NMR, UV–Vis, DSC, mass spectrometry and gave
satisfactory elemental analyses. They possessed good solubility in common organic solvents and good homogeneous film formation. The
optical energy band gap of DBBSBF was 3.27 eV between the HOMO energy level, 5.85 eV, measured by UPS and the LUMO, 2.58 eV,
calculated from absorption spectrum. A blue organic light emitting diode (OLED) based on the structure of ITO/TPD (60 nm)/DBBSBF
(40 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (100 nm) showed good performance. The luminance of 3125 cd/m2 was observed at a drive voltage of
12.8 V and the colour coordinate in CIE chromaticity was (0.14, 0.12). The external quantum efficiency was obtained to be 2.8% at
100 cd/m2. q 2003 Elsevier Science Ltd. All rights reserved.
1. Introduction
terms of a color purity and material stability for real
application in device.
Organic electroluminescent materials have recently
attracted much interest due to their physical properties and
potential applications in light-emitting device and flat panel
displays. To develop a blue electroluminescence emitter is
essential for the development of a full color display based
on the color changing medium technology or the RGB
filtered white emission.1,2 A number of blue electrolumi-
nescent materials have been synthesized. A fluorene, planar
structure of phenylene, is one of the choice for the blue.3–6
However, fluorene derivatives show an excimer formation,7,8
resulting in color impurity and shortening in the lifetime of
OLED device. In an efforts to reduce 0the excimer formation,
non-planar molecular structure, 9,9 -spirobifluorene com-
pounds have been introduced as EL materials.9–11 A series
of 9,90-spirobifluorene derivatives containing symmetrically
substituted phenylene groups12 has been used for blue light
emitting materials. The structural feature minimizes the
close packing of spiro-annulated molecules in the solid
state, resulting in less excimer formation in comparison with
fluorene compounds. However, even though they are good
candidates for the blue OLED, they still have a problem in
Here we report that regio- and stereoselective alkoxy-
substituted spirobifluorene compounds in only one side of
fluorene ring were designed and synthesized for the first
time. We expect that the unsymmetrically substituted
alkoxy groups may reduce intermolecular pi-electron
interactions of spirobifluorene moiety and keep stable blue
color. We also expect that the substituted alkoxy groups
may give a better solubility and a low tendency to crystallize
in the device. In this paper, we present our detailed results
on synthesis, characterization of DPBSBF 1a, DBBSBF 1b,
and DTBSBF 1c and also preliminary results of EL
behavior.
2. Results and discussion
2.1. Synthesis and characterization
The detailed synthesis of compounds, 1a–c is sketched in
Scheme 1. In order to regioselectively introduce0long alkoxy
groups at 30 and 60 position of 5a, we chose 3,3 -dimethoxy
biphenyl13 as a starting material. Compound 2 was prepared
from mono-bromination of 3,30-dimethoxy biphenyl,
followed by deprotection of 2-bromo-5,30-dimethoxy-
biphenyl to introduce longer alkoxy chain,14 and alkylation
Keywords: spirobifluorene; blue light emitting material; organic light
emitting device.
*
Corresponding author. Tel.: þ82-428601165; fax: þ82-428606836;
e-mail: hyoyoung@etri.re.kr
0040–4020/03/$ - see front matter q 2003 Elsevier Science Ltd. All rights reserved.
doi:10.1016/S0040-4020(03)00371-5

2774
H. Lee et al. / Tetrahedron 59 (2003) 2773–2779
Scheme 1. (i) NBS, DMF. (ii) BBr3, CH2Cl2. (iii) 1-Octyl bromide, K2CO3/KI, DMF, 1508C. (iv) t-BuLi, 2,7-Dibromo-fluoren-9-one, THF, 2788C.
(v) HCl/CH3CO2H. (vi) Aryl boronic acid, Pd(PPh3)4, 2 M-K2CO3, toluene, reflux. (vii) t-BuLi, triisopropylborate. (viii) Iodo terphenyl, Pd(PPh3)4, 2 M-
K2CO3, toluene, reflux.
with 1-octyl bromide gave compound 3. Compound 3 was
subjected to halogen–lithium exchange by t-BuLi and
2,7-dibromofluorene-9-one was then added to give com-
pound 4, followed by cyclization to give 2,7-dibromo-30,60-
bis(octyloxy)-9,90-spirobisfluorene, 5a and its geometrical
isomer, 2,7-dibromo-10,60-bis(octyloxy)-9,90-spirobis-
fluorene, 5b.15 Separation of geometrical isomers between
major compound 5a and 5b can be achieved from column
chromatography and/or re-crystallization from a mixed
solvent of n-hexane and dichloromethane. In order to get the
higher ratio of one form, 5a, several stereoselective control
experiments were performed by changing cyclization
reagent from polyphosphoric acid (PPA) to hydrochloric
acid/acetic acid and also by changing the concentration of 4
in hydrochloric acid/acetic acid. The stereoselective control
experiments showed that about 10 mmol concentration of 4
in hydrochloric acid/acetic acid (1/50) gave 94% of 5a over
5b. DPBSBF 1a and DBBSBF 1b were successfully
prepared by usi0ng Suzuki coupling reaction between
2,7-dibromo-30,6 -bis(octyloxy)-9,90-spirobisfluorene 5a
and phenylboronic acid and biphenylboronic acid, respec-
tively. In addition, DTBSBF 1c can be also pre0p0 ared from
Suzuki coupling reaction with 400-iodo[1,10;40,1 ]terphenyl
and spirobifluorene diboronic 0acid 6 which was obtained
from lithiated 2,7-dibromo-3 ,60-bis(octyloxy)-9,90-spiro-
bisfluorene and isopropylborate. Compounds 1a–c are
soluble in common organic solvents such as CHCl3,
CH2Cl2, THF, toluene, and chlorobenzene.
2.2. Thermal and physical properties
The thermal properties of 1a–c were examined by
Figure 1. Thermogravimetric analysis curve of (a) 1b and 1c.

H. Lee et al. / Tetrahedron 59 (2003) 2773–2779
2775
Figure 2. (a) The DSC data of 1b on first heating at 108C/min and cooling in air, (b) The DSC data of 1b on second heating at 108C/min and cooling in air.
thermogravimetric analysis (TGA) and differential scanning
calorimetry (DSC) under a nitrogen atmosphere. DSC of 1a
shows the low melting point at 418C and it easily formed
liquid crystalline state at room temperature. Therefore, we
did not study the properties of 1a for organic light emitting
device further. Figure 1 shows TGA curves of 1b and 1c.
The TGA curves show that decomposition temperature (Td)
of 1b starts at 3888C and for 1c at 4058C.
DSC measurements of 1b depicted in Figure 2(a) showed
Figure 3. The DSC data of 1c on heating/cooling curves.

2776
H. Lee et al. / Tetrahedron 59 (2003) 2773–2779
Figure 6. Band diagram of ITO/TPD/1b/Alq3/LiF/Al device.
amorphous glassy state of the transparent film of 1b is a
good candidate as an EL material.
2.3. PL and EL spectra
Figure 4. (a) and (b) show the UV and photoluminescent (PL) spectra of
1a–c in CHCl3 solution.
The absorption in Figure 4(a) and PL spectra in Figure 4(b)
of 1a–c dissolved in CHCl3 solution exhibit two peaks and
are red shift as the chain length of phenylene increases (365,
382 nm for PL spectra of 1a, 387, 407 nm for PL spectra of
1b, and 396, 416 nm for PL spectra of 1c).
that upon the first heating, it revealed the glass transition
temperature (Tg) of 708C on heating and melted at 1588C to
give an isotropic liquid and on cooling, no freezing points
were observed except for Tg at 608C on the first cooling.
Figure 5 shows the PL and electroluminescence (EL)
spectra of 1b fabricated by using vacuum deposition in film.
The PL and EL spectra in film exhibit two peaks at 450 as
EL and PL maximum peaks and 470 nm the emission
wavelength of PL and EL spectra are almost identical expect
relative intensity ratio between two peaks.
For second heating in Figure 2(b), there were no melting
points observed even though giving enough time to cool in
the air and giving a supercooled liquid state for several days.
However, DSC measurements of 1c shown in Figure 3
revealed the melting point at 2378C and freezing point at
1808C on every heating and cooling. These results imply
that white solid 1b forms an amorphous solid state right
after first heating. Once becoming amorphous solid state, it
does not go back to a crystalline state at all. As a result, the
2.4. Homo, Lumo energy band
Figure 6 shows a band diagram of ITO/TPD/1b/Alq3/LiF/Al
device. The optical energy band gap of 1b was 3.27 eV
between the HOMO energy level, 5.85 eV, measured by
UPS and the LUMO, 2.58 eV, calculated from absorption
spectrum, which was consistent with the result of the optical
threshold.
2.5. Electroluminescence properties
To investigate the EL properties of the 1b, the EL device
was fabricated in vacuum deposition method. The configu-
ration of the EL device was ITO/TPD (60 nm)/1b (40 nm)/
Alq3 (20 nm)/LiF (1 nm)/Al (100 nm). Figure 7 shows
maximum luminance of 3125 cd/m2 at a drive voltage of
12.8 V. The luminous efficiency was obtained to be 0.9 lm/
W at 100 cd/m2. The color coordinate in CIE chromaticity is
(0.14, 0.12), which is in a pure blue region. The external
quantum efficiency was obtained to be 2.8% at 100 cd/m2.
Figure 5. Photoluminescence (PL) spectrum (open circle) of 1b in film and
electroluminescence (EL) spectrum (solid square) of ITO/TPD (60 nm)/1b
(40 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (100 nm) fabricated by the vacuum
deposition.
3. Conclusion
In conclusion, the low molecular weight materials, 1a–c

H. Lee et al. / Tetrahedron 59 (2003) 2773–2779
2777
Figure 7. Current–voltage (I–V) and light–voltage (L–V) characteristics of EL devices fabricated by vacuum deposition method with the configurations of
ITO/TPD/1b/Alq3/LiF/Al (open circle and solid square, respectively). Inset: external quantum efficiency-voltage of 1b (solid diamond).
having unsymmetrically substituted alkoxy chains were
prepared in multi-step synthesis. They are very soluble in
common organic solvents. They also possess good film
forming properties. We fabricated the blue organic LED by
using 1b with vacuum deposition technique. We can
conclude that the unsymmetrically alkoxy substituted
spirobifluorenes in comparison with symmetrically substi-
tuted spiro-sexiphenyl12 help preventing intermolecular
pi-electron overlap and reducing the excimer formation,
resulting in preventing tailing phenomenon of emission
wavelength and giving purer blue color emission. From
these results, we believe that 1b is a good candidate for light
blue emitting materials in organic LEDs. By using 1b and
1c, we are currently investigating on the performance and
life time of the device, which will be presented in further
papers.
methoxybiphenyl can be prepared by literature method.14 A
solution of boron tribromide (137.12 mmol) was slowly
added to a solution of 2-bromo-5,30-dimethoxybiphenyl
(22.85 mmol) at 08C, followed by stirring for 1 h.
Purification by silica gel chromatography using 4% ethyl
acetate in dichloromethane gave pure 6-bromo-biphenyl-
3,30-diol (yield: 98%).15 Mp 110–1118C; IR (KBr) 3383.5
(broad), 2925.5, 1566.9, 1466.6, 1314.3, 1182.2, 1023.0,
1
836.0 cm21; H NMR (400 MHz, CDCl3) d 7.44 (d, 1H),
7.25 (m, 1H), 6.92–6.68 (m, 5H), 5.73 (s, 1H), 5.54 (s, 1H);
13C NMR (CDCl3) d 155.0, 154.9, 143.1, 142.3, 133.9,
129.2, 121.8, 118.1, 116.3, 116.2, 114.7, 112.8; MS: m/z (%)
128 (30), 157 (38), 185 (16), 264 (Mþ, 100). Anal. calcd for
C12H9BrO2: C, 54.37; H, 3.42. Found: C, 54.30; H, 3.50.
4.2.2. 2-Bromo-5,30-bis(octyloxy)-biphenyl (3). The
obtained 6-bromo-biphenyl-3,30-diol (22.43 mmol), 1-octyl
bromide (67.28 mmol), potassium carbonate (134.56 mmol)
and potassium iodide (22.43 mmol) were dissolved in
dimethylformamide (60 mL), followed by heating for
about 24 h at about 1508C. Purification by silica gel
chromatography using 4% dichloromethane in hexane
gave 2-bromo-5,30-bis(octyloxy)-biphenyl (6.36 g, yield:
58.1%). Mp 58–598C; IR (KBr) 2926.5, 2855.1, 1590.0,
1462.8, 1229.4, 698.1 cm21; 1H NMR (400 MHz, CDCl3) d
7.49 (d, J¼8.8 Hz, 1H), 7.30 (t, J¼11.0 Hz, 1H), 6.96–6.76
(m, 4H), 6.74 (dd, J¼8.8, 3.1 Hz, 1H), 3.98 (t, J¼6.6 Hz,
2H), 3.91 (t, J¼6.6 Hz, 2H), 1.80–1.74 (m, 4H), 1.44–1.40
(m, 4H), 1.32–1.28 (m, 16H), 0.88 (t, J¼6.8 Hz, 6H); 13C
NMR (CDCl3) d 158.7, 158.3, 143.3, 142.4, 133.6, 128.9,
121.5, 117.2, 115.5, 115.3, 113.9, 112.7, 68.3, 68.1, 31.8,
31.78, 29.36, 29.30, 29.29, 29.23, 29.21, 29.17, 26.1, 26.0,
22.6, 14.1; MS: m/z (%) 157 (12), 186 (13), 237 (7), 264
(100), 376 (20), 488 (Mþ, 80). Anal. calcd for C28H41BrO2:
C, 68.70; H, 8.44. Found: C, 68.70; H, 8.50.
4. Experimental
4.1. General remarks
NMR spectra were obtained on a Bruker Avance 400 MHz
FT NMR spectrometer at room temperature. UV–Vis
spectra were recorded on a Perkin–Elmer Lambda 9
UV/Vis spectrometer. Photoluminescence spectra were
obtained on a Perkin–Elmer LS 50. Mass spectra were
obtained on a Micromass autospec mass spectrometer.
Elemental analyses were obtained on a FISONS EA 1108.
TGA and DSC measurements were carried out using a
Perkin–Elmer 7 series thermal analyser system under N2 at
a heating rate of 10 K/min. All the solvents used in this
study were purified according to standard methods and THF
was distilled from sodium benzophenone-ketyl prior to use.
All other chemicals were used as purchased without further
purification.
4.2.3. 9-(5,30-Bis(octyloxy)-biphenyl-2-yl)-2,7-dibromo-
9H-fluorene-9-ol (4). 2-Bromo-5,30-bis(octyloxy)-biphenyl
(1.23 mmol) was dissolved in dried THF (30 mL) and
cooled to 2788C. Then, t-butyllithium (2.45 mmol) was
added slowly. The obtained resultant was stirred for 1 h at
4.2. Preparation of alkoxy-substituted spirobifluorene
derivatives
4.2.1. 6-Bromo-biphenyl-3,30-diol (2). 2-Bromo-5,30-di-

2778
H. Lee et al. / Tetrahedron 59 (2003) 2773–2779
2788C. After 1 h, 2,7-dibromofluorene-9-one (1.47 mmol)
dissolved in dried THF (20 mL) was added slowly, stirred
for about 1 h, allowed to warm to room temperature and
further stirred at room temperature for about 30 min.
Purification by silica gel chromatography using 30–40%
dichloromethane in hexane gave 9-(5,40-bis(octyloxy)-
biphenyl-2-yl)-2,7-dibromo-9H-fluorene-9-ol (yield: 68%).
Mp 103.5–1048C; IR (KBr) 3445.3, 2925.5, 2855.1, 1596.8,
reaction conditions. 2,7-dibromo-30,60-bis(octyloxy)-9,90-
spirobisfluorene (0.5 g, 0.68 mmol), 4-phenyl boronic acid
(0.21 g, 1.71 mmol), tetrakis(triphenylphosphine)palladium
(0.24 g, 0.20 mmol), 2 M-sodium carbonate (2.1 mL,
4.10 mmol) and toluene (29 mL) were simultaneously
mixed, frozen under liquid nitrogen, evacuated by a vacuum
pump and then warmed to room temperature to be melted.
This procedure was repeated twice, followed by injection of
nitrogen. The mixed solution was refluxed for 2 days and
cooled to room temperature. Thereafter, a small amount of
distilled water was added, and the organic layer was filtered
three times with dichloromethane, dried over sodium
sulfate. Then, the dichloromethane was concentrated
under reduced pressure. Purification by silica gel chroma-
tography using 10% dichloromethane in hexane, followed
by recrystallization using a mixed solvent of hexane and
dichloromethane gave white solid 1a (0.407 g, yield: 82%).
UV (CHCl3): lmax nm (1, M21 cm21), 315 (19400), 332
(18600); IR (KBr) 2925.5, 2854.2, 1608.4, 1463.7, 1224.5,
1
1467.6, 1227.5, 877.5, 810.0 cm21; H NMR (400 MHz,
CD2Cl2) d 8.25 (d, J¼8.8 Hz, 1H), 7.36–7.29 (m, 4H),
7.07–7.02 (m, 3H), 6.54 (t, J¼7.9 Hz, 1H), 6.48 (d, J¼
2.8 Hz, 1H), 6.39 (dd, J¼2.6, 1.0 Hz, 1H), 5.65 (t, J¼
2.0 Hz, 1H), 5.61 (d, J¼7.5 Hz, 1H), 3.94 (t, J¼6.6 Hz, 2H),
3.52 (t, J¼6.7 Hz, 2H), 2.41 (s, 1H), 1.76 (m, 2H), 1.59 (m,
2H), 1.42 (m, 4H), 1.34–1.27 (m, 16H), 0.92–0.86 (m, 6H);
13C NMR (CDCl3) d 158.6, 157.8, 152.9, 142.3, 141.6,
138.5, 138.4, 132.1, 130.4, 128.1, 128.0, 127.9, 127.7,
122.1, 122.0, 121.9, 121.8, 121.6, 117.6, 114.2, 113.3,
113.2, 82.2, 68.5, 67.7, 32.23, 32.18, 29.82, 29.69, 29.67,
29.64, 29.61, 26.42, 26.37, 23.06, 23.03, 14.26, 14.23; MS:
m/z (%) 186 (18), 201 (54), 313 (34), 425 (41), 635 (18), 732
(10), 748 (Mþ, 100). Anal. calcd for C41H48Br2O3: C, 65.78;
H, 6.46. Found: C, 65.90; H, 6.50.
1
1176.4, 759.8 cm21; H NMR (400 MHz, CD2Cl2) d 7.96
(d, J¼7.8 Hz, 2H), 7.68 (dd, J¼4.0, 3.9 Hz, 2H), 7.48–7.45
(m, 6H), 7.34–7.32 (m, 4H), 7.26 (m, 2H), 7.02 (d,
J¼1.4 Hz, 2H), 6.71 (d, J¼1.7 Hz, 4H), 4.07 (t, J¼6.5 Hz,
4H), 1.85 (m, 4H), 1.53 (m, 4H), 1.44–1.35 (m, 16H), 0.94
(t, J¼6.8 Hz, 6H); 13C NMR (CD2Cl2) d 160.0, 150.9,
143.6, 141.6, 141.19, 141.18, 140.9, 129.0, 127.6, 127.3,
127.1, 124.9, 122.7, 120.8, 115.0, 106.3, 68.8, 65.3, 32.3,
29.82, 29.81, 29.7, 26.5, 23.1, 14.3; MS: m/z (%) 499 (17),
611 (8), 648 (16), 724 (Mþ, 100). Anal. calcd for C53H56O2:
C, 87.80; H, 7.79. Found: C, 87.80; H, 7.77.
4.2.4. 2,7-Dibromo-30,60-bis(octyloxy)-9,90-spirobisfluor-
ene (5a) and 2,7-dibromo-10,60-bis(octyloxy)-9,90-spiro-
bisfluorene (5b). 9-(5,30-Bis(octyloxy)-biphenyl-2-yl)-2,7-
dibromo-9H-fluorene-9-ol (0.5 g, 0.668 mmol) was mixed
with acetic acid (50 mL) and hydrochloric acid (1 mL) and
stirred for about 22 h at room temperature. Purification by
silica gel chromatography using 4% dichloromethane in
hexane, followed by recrystallization using a mixed solvent
of hexane and dichloromethane gave white solid 5a (yield:
94%) and 5b (yield: 6%).
4.2.6. 2,7-Dibiphenyl-3060-bis(0octyloxy)-9,90-spirobis-
fluorene (1b). 2,7-Dibromo-30,6 -bis(octyloxy)-9,90-spiro-
bisfluorene (0.35 mmol), 4-biphenyl boronic acid
(0.89 mmol),
tetrakis(triphenylphosphine)palladium
Compound 5a. Mp 118.5–1198C; IR (KBr) 2925.5, 2854.2,
1
(0.11 mmol), 2 M-sodium carbonate (2.13 mmol) and
toluene (15 mL) were simultaneously mixed, frozen under
liquid nitrogen, evacuated by a vacuum pump and then
warmed to room temperature to be melted. The mixed
solution was refluxed for 2 days. Purification by silica gel
chromatography using 20% dichloromethane in hexane,
followed by recrystallization using a mixed solvent of
hexane and dichloromethane gave white solid 1b (yield:
90%). UV (CHCl3): lmax nm (1, M21 cm21), 331 (22300),
347 (21000); IR (KBr) 2925.5, 2854.2, 1607.4, 1464.7,
1608.4, 1451.2, 1305.5, 1179.3, 1058.7, 807.0 cm21; H
NMR (400 MHz, CDCl3) d 7.60 (d, J¼8.2 Hz, 2H), 7.44
(dd, J¼8.1, 1.8 Hz, 2H), 7.29 (d, J¼2.3 Hz, 2H), 6.82 (d,
J¼1.7 Hz, 2H), 6.66 (dd, J¼7.1, 3.6 Hz, 2H), 6.56 (d, J¼
8.3 Hz, 2H), 4.02 (t, J¼6.5 Hz, 4H), 1.80 (m, 4H), 1.47 (m,
4H), 1.31 (m, 16H), 0.88 (t, J¼3.5 Hz, 6H); 13C NMR
(CDCl3) d 159.7, 151.1, 143.0, 139.6, 139.4, 130.9, 127.3,
124.6, 121.8, 121.2, 114.7, 105.9, 68.3, 64.4, 31.8, 29.37,
29.35, 29.25, 26.11, 22.7, 14.1; MS: m/z (%) 425 (11), 505
(14), 617 (5), 730 (Mþ, 100). Anal. calcd for C41H46Br2O2:
C, 67.40; H, 6.35. Found: C, 67.45; H, 6.40.
1304.6 1224.6, 1175.4, 816.7, 763.7 cm21
;
1H NMR
(400 MHz, CD2Cl2) d 7.96 (d, J¼7.9 Hz, 2H), 7.68 (dd,
J¼5.2, 1.7 Hz, 2H), 7.59–7.52 (m, 12H), 7.40–7.38 (m,
8H), 7.01 (d, J¼1.5 Hz, 2H), 6.68 (d, J¼1.0 Hz, 4H), 4.04
(t, J¼6.6 Hz, 4H), 1.80 (m, 4H), 1.48 (m, 4H), 1.40–1.29
(m, 16H), 0.89 (t, J¼6.9 Hz, 6H); 13C NMR (CD2Cl2) d
159.3, 150.9, 143.5, 141.4, 140.9, 140.8, 140.2, 140.0,
129.1, 127.7, 127.5, 127.2, 126.9, 124.9, 122.5, 120.8,
114.9, 106.1, 68.7, 65.2, 32.2, 29.8, 29.7, 29.6, 26.4, 23.0,
14.2; MS: m/z (%) 651 (21), 764 (7), 877 (Mþ, 100). Anal.
calcd for C65H64O2: C, 89.00; H, 7.35. Found: C, 88.85; H,
7.68.
Compound 5b. Mp 128.5–1298C; IR (KBr) 2925.5, 2854.2,
1585.2, 1456.0, 1267.0, 1058.7, 807.0 cm21 1H NMR
;
(400 MHz, CDCl3) d 7.61 (d, J¼8.1 Hz, 2H), 7.43–7.30 (m,
5H), 6.83 (s, 2H), 6.64–6.62 (m, 2H), 6.51 (d, J¼8.2 Hz,
1H), 4.01 (t, J¼6.5 Hz, 2H), 3.51 (t, J¼5.9 Hz, 2H), 1.81
(quint, 2H), 1.49 (m, 2H), 1.31–1.24 (m, 12H), 1.08 (m,
4H), 1.02 (m, 4H), 0.88 (m, 6H); 13C NMR (CDCl3) d 159.6,
155.2, 150.0, 143.5, 143.0, 140.2, 139.3, 134.2, 130.4,
123.0, 126.6, 124.4, 121.4, 120.8, 114.6, 112.1, 111.1,
106.2, 68.3, 67.3, 63.7, 31.9, 31.8, 29.4, 29.3, 29.2, 28.9,
26.1, 25.4, 22.7, 22.7, 14.2, 14.1. MS: m/z (%) 425 (6), 506
(15), 730 (Mþ, 100).
4.2.7. 3060-Bis(octyloxy)-9,90-spirobisfluorenyl-2,7-bis-
boronic0acid (6). A solution of 2,7-dibromo-30,60-bis(octyl-
oxy)-9,9 -spirobisfluorene (0.68 mmol) dissolved in dry-
THF (100 mL) was cooled to cooled to 2788C. Then,
t-butyllithium (3.76 mmol) was added slowly. The reaction
4.2.5. 2,7-Bisphenyl-3060-bis(octyloxy)-9,90-spirobisfluor-
ene (1a). The compound was prepared under Suzuki

H. Lee et al. / Tetrahedron 59 (2003) 2773–2779
2779
mixture was stirred for 2 h at 2788C. After 2 h, triisopro-
pylborate (8.2 mmol) was added. The reaction mixture was
stirred for an hour at 2788C and kept to stir overnight while
warming to room temperature. Purification by silica gel
chromatography using 30–40% ethylacetate in hexane gave
6 (yield: 75.2%). Mp 145–1468C; IR (KBr) 3218.7 (broad),
1456.0, 1195.7, 798.4 cm21; 1H NMR (400 MHz, CDCl3) d
7.93 (d, J¼7.6 Hz, 2H), 7.85 (d, J¼7.64 Hz, 2H), 7.62 (d,
J¼2.3 Hz, 2H), 7.10 (s, 2H), 6.65 (dd, J¼8.36, 2.33 Hz,
2H), 6.46 (d, J¼8.3 Hz, 2H), 4.02 (t, J¼6.3 Hz, 4H), 1.74
(m, 4H), 1.42 (m, 4H), 1.29 (m, 16H), 0.85 (t, J¼3.5 Hz,
6H); 13C NMR (CDCl3) d 159.0, 148.3, 142.9, 142.8, 140.9,
133.7, 129.2, 124.1, 119.5, 114.6, 106.2, 67.7, 64.1, 31.3,
28.9, 28.7, 25.6, 25.1, 14.0.
15 min, respectively, and finally treated with O2 plasma for
5 min after blowing the cleaned substrate with N2 for 5 min.
TPD, 1b, Alq3, and LiF/Al layer were evaporated under
vacuum. Electroluminescence (EL) spectra were recorded
using Minolta CS-1000 and Current–voltage (I–V) and
radiance–voltage characteristics of the devices were
simultaneously measured with a Keithley 2400 Source
Measure Unit and a Minolta LS-100. All device testing was
carried out at room temperature under ambient atmosphere.
Acknowledgements
The authors thank the Korean Ministry of Information and
Communication for support of this work (Grant No. 2001-s-
161).
4.2.8. 2,7-Diterphenyl-3060-bis(octyloxy)-9,90-spirobis-
fluo0rene00 (1c). Compound
6
(0.167 mmol), 400-iodo-
[1,1 ;40,1 ]terphenyl (0.50 mmol), tetrakis(triphenylphos-
phine)palladium (0.01 mmol) and 2 M-sodium carbonate
(1.67 mmol) were mixed, frozen under liquid nitrogen,
evacuated by a vacuum pump and then warmed to room
temperature to be melted. The mixed solution was refluxed
for 2 days and cooled to room temperature. Purification by
silica gel chromatography using 10–30% dichloromethane
in hexane gave white solid 1c (yield: 30%). UV (CHCl3):
lmax nm (1, M21 cm21), 331 (18600), 350 (18400); IR
References
1. Chen, C. H.; Shi, J. M. Coord. Chem. Rev. 1998, 171,
161–174.
2. Kido, J.; Endo, J. Chem. Lett. 1997, 593.
3. Scherf, U.; List, E. J. W. Adv. Mater. 2002, 14, 477.
4. Neher, D. Macromol. Rapid. Commun. 2001, 22, 1366.
5. Whitehead, K. S.; Grell, M.; Bradley, D. D. C.; Jandke, M.;
Strohriegl, P. Appl. Phys. Lett. 2000, 76, 2946.
6. Oda, M.; Meskers, S. C. J.; Nothofer, H. G.; Scherf, U.; Neher,
D. Synth. Met. 2000, 111–112, 575.
(KBr) 2925.5, 1610.3, 1462.8, 1222.7, 812.9 cm21 1H
;
NMR (400 MHz, CD2Cl2) d 7.97 (d, J¼7.7 Hz, 2H), 7.68–
7.63 (m, 18H), 7.55 (d, J¼8.4 Hz, 4H), 7.45 (m, 4H), 7.39
(m, 4H), 7.02 (t, J¼1.0 Hz, 2H), 6.69 (d, J¼1.1 Hz, 4H),
4.05 (t, J¼6.6 Hz, 4H), 1.82 (m, 4H), 1.50 (m, 4H), 1.36–
1.27 (m, 16H), 0.89 (t, J¼6.9 Hz, 6H); 13C NMR (CD2Cl2) d
160.0, 151.0, 143.6, 141.5, 141.0, 140.9, 140.6, 140.4,
140.2, 139.7, 139.65, 129.2, 127.77, 127.69, 127.56, 127.45,
127.26, 127.0, 124.9, 122.6, 120.9, 115.0, 106.2, 68.8, 65.3,
32.2, 29.8, 29.7, 26.5, 23.0, 14; MS: m/z (%) 803 (20), 916
(6), 1001 (21), 1029 (Mþ, 100). Anal. calcd for C77H72O2:
C, 89.84; H, 7.05. Found: C, 89.90; H, 7.01.
7. Yang, Y.; Pei, Q. J. Appl. Phys. 1997, 81, 3294.
8. Stephan, O.; Collomb, V.; Vial, J.-C.; Armand, M. Synth. Met.
2000, 113, 257.
9. Kreuder, W.; Lupo, D.; Salbeck, J.; Schenk, H.; Stehlin,
T. U.S. Patent 5 621 131, 1998.
10. Lupo, D.; Salbeck, J.; Schenk, H.; Stehlin, T.; Stern, R.; Wolf,
A. U.S. Patent 5 840 217, 1998.
11. Rietz, R.-R.; Wernet, W. U.S. Patent 6 132 641, 2000.
¨
12. Salbeck, J.; Weissortel, F.; Yu, N.; Bauer, J.; Bestgen, H.
Synth. Met. 1997, 91, 209.
4.3. Fabrication and measurements of EL device
The EL device fabricated by vacuum deposition technique
was constructed using a triple layer structure with TPD as
the hole injecting layer, 1b as an emitting layer, and Alq3 as
an electron transporting layer. The ITO-coated glass
substrate was cleaned by sequential ultrasonic sonic
washing in acetone, methanol, and deionized water for
13. Geiger, M. S.; Joannic, M.; Pesson, M.; Techer, H.; Lagrance,
M. E.; Aurousseau, M. Chim. Ther. 1966, 7, 425.
14. McOmie, J. F. W.; Watts, M. L.; West, D. E. Tetrahedron
1968, 24, 2289.
15. Yu, W.-L.; Pei, J.; Huang, W.; Heeger, A. J. Adv. Mater. 2000,
12, 828.