Macromolecules
ARTICLE
Chart 1
bombardment (FAB). LC behavior and phase transition behavior were
examined on an Olympus model BX-51 polarizing microscope equipped
with Mettler hot-stage models FP-90 and FP-82. Thermotropic proper-
ties of compounds were determined with a differential scanning
calorimeter (DSC) on a Seiko I&E SSC-5200 and DSC220C at a
scanning rate of 10 ꢀC/min. At least three scans were performed for each
sample to verify the reproducibility. Wide-angle X-ray diffraction
(WAXD) measurements of the sample films were carried out on a
Rigaku Ultima using Cu KR radiation. AFM was performed in the
tapping mode with a NanoNavi probe station and an S-image unit (SII
NanoTechnology Inc., Tokyo, Japan).
125.10, 124.86, 122.63, 115.33, 114.76, 91.72, 88.19, 70.97, 69.86, 69.66,
68.36, 67.53, 66.69, 64.80, 29.79, 29.45, 29.42, 29.33, 29.22, 29.18, 28.61,
26.00, 25.97, 18.32, 15.16. MS (FAB) 655.3447 (MH+).
p-oxyAzo. Compound 4 (0.25 g, 0.32 mmol) and AIBN (5.0 mg,
3.2 μmol) were dissolved in dry DMF (10 mL) and placed in a
polymerization tube. After several freezeꢀpumpꢀthaw cycles, the tube
was sealed under high vacuum. Then, the tube was kept at 60 ꢀC for 48 h.
The resulting solution was cooled to room temperature and poured into
400 mL of methanol with vigorous stirring to precipitate the polymer.
The polymer obtained was purified by repeated reprecipitation from
DMF into a large excess of methanol and dried under vacuum for 48 h to
yield 0.14 g of p-oxyAzo in 56% conversion.
3-(3,6-Dioxaoctyloxy)bromobenzene (5). Yield 3.5 g (68%)
of an yellow oil. 1H NMR (CDCl3) δ: 7.21 (1H, t, J = 7.9 Hz), 7.08 (1H,
dt, J = 7.6, 1.1 Hz), 7.03 (1H, t, J = 2.0 Hz), 6.92 (1H, ddd, J = 8.3, 2.6, 0.9
Hz), 4.13 (2H, t, J = 4.9 Hz), 3.86 (2H, t, J = 4.9 Hz), 3.72 (2H, t, J = 4.6
Hz), 3.61 (2H, t, J = 4.7 Hz), 3.54 (2H, q, J = 7.0 Hz), 3.05 (1H, s), 1.22
(3H, t, J = 7.0 Hz).
4-(3,6-Dioxaoctyloxy)-2-ethynylbenzene (2)12. Yield 3.5 g
(68%) of yellow oil. 1H NMR (CDCl3, δ, ppm): 7.41 (2H, d, J = 8.6 Hz),
6.85 (2H, d, J = 8.8 Hz), 4.16ꢀ4.09 (2H, m), 3.87 (2H, t, J = 4.8 Hz),
3.73ꢀ3.71 (2H, m), 3.62ꢀ3.60 (2H, m), 3.54 (2H, q, J = 7.0 Hz), 2.99
(1H, s), 1.22 (3H, t, J = 7.1 Hz).
4-(4-(3,6-Dioxaoctyloxy)phenylethynyl)-40-(10-hydro-
xydecyloxy)azobenzene (3). A mixture of 1 (4.2 g, 9.6 mmol), 2
(2.3 g, 9.6 mmol), PdCl2(PPh3)2 (0.32 g, 4.6 mmol), CuI (0.30 g,
1.6 mmol), PPh3 (0.64 g, 2.4 mmol), triethylamine (50 mL), and THF
(50 mL) was refluxed at 60 ꢀC for 6 h under a N2 atmosphere. After
cooling to room temperature, the reaction mixture was extracted with
ethyl acetate. The organic layer was washed with 1 N HCl and water and
dried over anhydrous magnesium sulfate. The crude solid was purified
by column chromatography (silica gel; eluent: ethyl acetate/hexane =
4-(3-(3,6-Dioxaoctyloxy)phenylethynyl)-40-(10-hydro-
xydecyloxy)azobenzene (6). A mixture of 5 (2.0 g, 8.5 mmol), 1
(3.7 g, 8.5 mmol), PdCl2(PPh3)2 (0.30 g, 0.43 mmol), CuI (0.29 g,
1.5 mmol), PPh3 (0.60 g, 2.3 mmol), triethylamine (50 mL), and THF
(40 mL) was refluxed at 60 ꢀC for 6 h under a N2 atmosphere. After
cooling to room temperature, the reaction mixture was extracted with
ethyl acetate. The organic layer was washed with 1 N HCl and water and
dried over anhydrous magnesium sulfate. The crude solid was purified
by column chromatography (silica gel; eluent: ethyl acetate/chloroform
1
1:4) to yield 2.5 g (44%) of orange solid (mp 200 ꢀC). H NMR
(CDCl3) δ: 7.91 (2H, d, J = 8.8 Hz), 7.86 (2H, d, J = 8.4 Hz), 7.62 (2H,
d, J = 8.4 Hz), 7.48 (2H, d, J = 8.8 Hz), 7.00 (2H, d, J = 9.0 Hz), 6.91 (2H,
d, J = 8.6 Hz), 4.17ꢀ4.13 (4H, m), 4.04 (2H, t, J = 6.5 Hz), 3.88 (2H, t,
J = 4.8 Hz), 3.74ꢀ3.72 (2H, m), 3.66ꢀ3.63 (2H, m), 3.55 (2H, q, J =
7.0 Hz), 1.82 (2H, t, J = 7.2 Hz), 1.48ꢀ1.33 (14H, m), 1.22 (3H, t, J =
7.0 Hz).
1
= 1:5) to yield 3.2 g (64%) of orange solid (mp 126 ꢀC). H NMR
(CDCl3) δ: 7.92 (2H, d, J = 8.6 Hz), 7.87 (2H, d, J = 8.4 Hz), 7.65 (2H,
d, J = 8.3 Hz), 7.26 (1H, t, J = 7.8 Hz), 7.15 (1H, d, J = 7.5 Hz), 7.10
(1H, s), 7.00 (2H, d, J = 9.0 Hz), 6.97 (1H, dd, J = 21.9, 8.5 Hz), 4.17
(4H, t, J = 4.7 Hz), 4.04 (2H, t, J = 6.4 Hz), 3.89 (2H, t, J = 4.8 Hz), 3.74
(2H, t, J = 4.6 Hz), 3.65 (2H, t, J = 6.1 Hz), 3.55 (2H, q, J = 7.0 Hz), 1.82
(2H, t, J = 7.1 Hz), 1.57ꢀ1.33 (14H, m), 1.22 (3H, t, J = 7.0 Hz).
10-[4-(4-{3-(3,6-Dioxaoctyloxy)phenylethynyl}phenyla-
zo)phenoxy]decyl Methacrylate (7). A solution of methacryloyl
chloride (0.63 g, 6.0 mmol) in THF (60 mL) was added dropwise at 0 ꢀC
to a mixture of 6 (1.2 g, 2.0 mmol), triethylamine (0.60 g, 6.0 mmol), and
a trace amount of hydroquinone, and the reaction mixture was stirred at
room temperature for 24 h. The solution was poured into saturated
aqueous sodium hydrogen carbonate, and the product was extracted
with ethyl acetate. After the organic layer was dried with anhydrous
magnesium sulfate, the solvent was removed by evaporation. The crude
solid was purified by column chromatography (silica gel, chloroform as
eluent) and finally recrystallized from methanol to yield 0.82 g (63%) of
10-[4-(4-{4-(3,6-Dioxaoctyloxy)phenylethynyl}phenyla-
zo)phenoxy]decyl Methacrylate (4). A solution of methacryloyl
chloride (0.59 g, 5.6 mmol) in THF (50 mL) was added dropwise at 0 ꢀC
to a mixture of 3 (1.1 g, 1.9 mmol), triethylamine (0.57 g, 5.6 mmol), and
a trace amount of hydroquinone, and the reaction mixture was stirred at
room temperature for 24 h. The solution was poured into saturated
aqueous sodium hydrogen carbonate, and the product was extracted
with ethyl acetate. After the organic layer was dried with anhydrous
magnesium sulfate, the solvent was removed by evaporation. The crude
solid was purified by column chromatography (silica gel, chloroform as
eluent) and finally recrystallized from methanol to yield 0.42 g (33%) of
1
an orange solid (mp 193 ꢀC). H NMR (CDCl3) δ: 7.90 (2H, d,
J = 9.0 Hz), 7.85 (2H, d, J = 8.6 Hz), 7.61 (2H, d, J = 8.6 Hz), 7.47 (2H, d,
J = 9.0 Hz), 6.99 (2H, d, J = 9.0 Hz), 6.90 (2H, d, J = 8.8 Hz), 6.09
(1H, dd, J = 1.7, 1.0 Hz), 5.53 (1H, t, J = 1.6 Hz), 4.17ꢀ4.11 (4H, m),
4.02 (2H, t, J = 6.5 Hz), 3.86 (2H, t, J = 4.9 Hz), 3.73ꢀ3.71 (2H, m),
3.62ꢀ3.60 (2H, m), 3.53 (2H, q, J = 7.0 Hz), 1.94 (3H, dd, J = 1.6, 1.0
Hz), 1.85ꢀ1.25 (8H, m), 1.22 (3H, t, J = 7.0 Hz).13C NMR (CDCl3) δ:
167.52, 161.90, 159.10, 151.79, 146.95, 136.58, 133.13, 132.16, 125.60,
1
an orange solid (mp 104 ꢀC). H NMR (CDCl3) δ: 7.91 (2H, d,
J = 8.8 Hz), 7.87 (2H, d, J = 8.4 Hz), 7.64 (2H, d, J = 8.4 Hz), 7.26 (1H, t,
J = 7.9 Hz), 7.15 (1H, d, J = 7.5 Hz), 7.10 (1H, s), 7.00 (2H, d, J = 9.0
Hz), 6.94 (1H, d, J = 8.1 Hz), 6.10 (1H, s), 5.54 (1H, s), 4.18ꢀ4.12
(4H, m), 4.04 (2H, t, J = 6.5 Hz), 3.88 (2H, t, J = 4.8 Hz), 3.74 (2H, t, J =
4.7 Hz), 3.63 (2H, t, J = 4.7 Hz), 3.55 (2H, q, J = 7.0 Hz), 1.94 (3H, s),
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dx.doi.org/10.1021/ma200558t |Macromolecules 2011, 44, 5605–5611