8620 Chen et al.
Macromolecules, Vol. 38, No. 21, 2005
9,9-Dihexyl-2-(2′-phenyl-1-ethynyl)fluorene (7). By fol-
lowing the procedure of 1 and using 2-bromo-9,9-dihexylfluo-
rene as starting material, the compound 7 was obtained as
white crystals with mp 67 °C (85% yield). 1H NMR (CDCl3, δ,
ppm): 0.85-1.01 (t, J ) 6.8 Hz, 6H, fluorene-(CH2)4-CH2CH3),
1.23-1.44 (m, 16H, fluorene-CH2-(CH2)4-CH3), 2.56-2.84 (m,
4H, fluorene-CH2-(CH2)4-CH3), 6.99-7.08 (m, 2H, aromatic-
H), 7.16-7.27 (m, 7H, aromatic-H), 7.44-7.47 (m, 12H,
aromatic-H), 7.59-7.61 (m, 1H, aromatic-H).
Scheme 3. Synthesis of Polymers P1-P7
1-(9,9-Dihexyl-2-fluorenyl)-2-phenyl-1,2-ethanedione (8).
By following the procedure of 2 and using 7 as starting
material, compound 8 was obtained as a deep-yellow liquid
1
(93% yield). H NMR (CDCl3, δ, ppm): 0.91-0.94 (t, J ) 6.8
Hz, 6H, fluorene-(CH2)4-CH2CH3), 1.23-1.44 (m, 16H, fluo-
rene-CH2-(CH2)4-CH3), 2.56-2.84 (m, 4H, fluorene-CH2-(CH2)4-
CH3), 6.99-7.03 (m, 1H, aromatic-H), 7.25-7.29 (m, 1H,
aromatic-H), 7.43-7.45 (d, J ) 7.0 Hz, 1H, aromatic-H), 7.48-
7.59 (m, 3H, aromatic-H), 7.70-7.74 (m, 4H, aromatic-H), 7.80
(s, 1H, aromatic-H).
Diethyl 4-(9,9-Dihexyl-2-fluorenyl)-2-oxo-5-phenyl-3,5-
cyclopentadiene-1,3-dicarboxylate (9). By following the
procedure of 3 and using 8 as starting material, compound 9
was obtained as deep-red liquid (74% yield). 1H NMR (CDCl3,
δ, ppm): 0.87-0.93 (t, J ) 6.8 Hz, 6H, fluorene-(CH2)4-
CH2CH3), 1.23-1.44 (m, 16H, fluorene-CH2-(CH2)4-CH3), 1.44-
1.48 (m, 6H, CO2CH2CH3), 2.56-2.84 (m, 4H, fluorene-CH2-
(CH2)4-CH3), 4.31-4.36 (m, 4H, CO2CH2CH3), 6.82 (d, J ) 7.0
Hz, 1H, aromatic-H), 6.99-7.09 (m, 2H, aromatic-H), 7.24-
7.31 (m, 2H, aromatic-H), 7.38-7.53 (m, 4H, aromatic-H),
7.61-7.66 (m, 2H, aromatic-H), 7.92 (s, 1H, aromatic-H).
Diethy 2-Phenyl-3-(9,9-dihexylfluoren-2-yl)terephtha-
late (10). By following the procedure of 4 and using 9 as
starting material, compound 10 was obtained as a brown oil
1
(75% yield). H NMR (CDCl3, δ, ppm): 0.91-0.94 (t, J ) 6.8
Hz, 6H, fluorene-(CH2)4-CH2CH3), 1.28-1.32 (t, 6H, -CO2-
CH2CH3), 1.23-1.44 (m, 16H, fluorene-CH2-(CH2)4-CH3), 1.44-
1.48 (m, 6H, -CO2CH2CH3), 2.56-2.84 (m, 4H, fluorene-CH2-
(CH2)4-CH3), 4.21-4.27 (m, 4H, -CO2CH2CH3), 6.52 (d, J )
7.0 Hz, 1H, aromatic-H), 6.99-7.05 (m, 2H, aromatic-H), 7.17-
7.39 (m, 7H, aromatic-H), 7.59-7.60 (d, J ) 7.6 Hz, 1H,
aromatic-H), 7.74-7.76 (s, 1H, aromatic-H), 8.01-8.08 (m, 2H,
aromatic-H).
1,4-Bis(hydroxymethyl)-2-phenyl-3-(9,9-dihexylfluoren-
2-yl)benzene (11). By following the procedure of 5 and using
10 as starting material, compound 11 was obtained as yellow
crystals with mp 185 °C (90% yield). 1H NMR (CDCl3, δ,
ppm): 0.91-0.94 (t, 6H, fluorene-(CH2)4-CH2CH3), 1.23-1.44
(m, 16H, fluorene-CH2-(CH2)4-CH3), 2.56-2.84 (m, 4H, fluo-
rene-CH2-(CH2)4-CH3), 4.90 (m, 4H, -CH2OH), 6.99-7.40 (m,
10H, aromatic-H), 7.46-7.48 (d, J ) 7.6 Hz, 1H, aromatic-H),
7.59-7.60 (m, 1H, aromatic-H), 7.75-7.77 (s, 1H, aromatic-
H).
1,4-Bis(chloromethyl)-2-phenyl-3-(9,9-dihexylfluoren-
2-yl)benzene (M2). To a solution of 11 (1.0 g, 1.83 mmol) in
anhydrous CH2Cl2 (10 mL), 5 mL of thionyl chloride (SOCl2)
was added and stirred overnight under a nitrogen atmosphere.
Water was then added dropwise into the solution to destroy
excess thionyl cloride. The mixture was extracted with 10%
NaHCO3(aq), and the organic phase was concentrated in vacuo.
The crude product was purified by gel chromatography (silica
gel, hexane:ethyl acetate ) 10:1 as the eluent) to give a pale-
yellow liquid (1.1 g, 94%). 1H NMR (CDCl3, δ, ppm): 0.91-
0.94 (t, J ) 6.8 Hz, 6H, fluorene-(CH2)4-CH2CH3), 1.23-1.44
(m, 16H, fluorene-CH2-(CH2)4-CH3), 2.56-2.84 (m, 4H, fluo-
rene-CH2-(CH2)4-CH3), 5.02 (m, 4H, -CH2Cl), 6.99-7.40 (m,
10H, aromatic-H), 7.46-7.48 (d, J ) 7.6 Hz, 1H, aromatic-H),
7.59-7.60 (m, 1H, aromatic-H), 7.75-7.77 (s, 1H, aromatic-
H).
the monomer M1 (1.43 g, 2.5 × 10-3 M) in THF (100 mL), a
solution of potassium tert-butoxide (tert-BuOK, 12 equiv) in
THF (20 mL) was added. The resulting mixture was stirred
at room temperature for 24 h under a nitrogen atmosphere. A
solution of 2,6-di-tert-butylphenol (6 equiv) as end-capping
agent in THF (20 mL) was then added and stirred for 6 h.
The polymer was obtained by pouring the mixture into
methanol and filtered. It was purified by dissolving in THF
and reprecipitated from methanol twice. After drying under
vacuum for 24 h, the polymer was obtained as a yellow solid
(0.53 g, 52%).
Device Fabrication and Measurements. Double-layer
devices were fabricated as sandwich structures between
calcium (Ca) cathodes and indium-tin oxide (ITO) anodes.
ITO-coated glass substrates were cleaned sequentially in
ultrasonic baths of detergent, 2-propanol/deionized water (1:1
volume) mixture, toluene, deionized water, and acetone. A 50
nm thick hole injection layer of poly(ethylenedioxythiophene)
(PEDOT) doped with poly(styrenesulfonate) (PSS) was spin-
coated on top of ITO from a 0.7 wt % dispersion in water and
dried at 150 °C for 1 h in a vacuum. Thin films of synthesized
polymers were spin-coated from toluene solutions onto the
PEDOT layer and dried at 50 °C overnight in a vacuum. The
thickness of the active layer was ca. 50 nm. Finally, 35 nm
Ca and 100 nm Al electrodes were made through a shadow
mask onto the polymer films by thermal evaporation using an
AUTO 306 vacuum coater (BOC Edwards, Wilmington, MA).
Evaporations were carried out typically at base pressures
lower than 2 × 10-6 Torr. The active area of each EL device
was 4 mm2, and the device was characterized following a
published protocol.19
1,4-Bis(bromomethyl)-2,5-dimethoxybenzene (M3) and
1,4-Bis(bromomethyl)-2-methoxy-5-(2′-ethylhexoxy)ben-
zene (M4). Monomers M3 and M4 were synthesized as
described previously in the literature.17,18
Synthesis of Polymers: General Procedure. Scheme 3
outlines the synthesis of polymers P1-P7. An experimental
procedure for the polymer P1 is given below. To a solution of