Macromolecules
Article
ments were carried out using a quartz cuvette with a path length of 1
cm. Transmission electron microscopy (TEM) images were obtained
using a JEM-1400 operating at 120 kV (JEOL, Tokyo, Japan). For the
TEM measurements, a drop of each sample in a mixed solvent of
toluene/n-hexane was placed on a carbon-coated copper grid and
allowed to evaporate under ambient conditions. The sample was
stained by placing a drop of uranyl acetate solution (2 wt %) onto the
surface of the sample-loaded grid. The deposited sample was allowed
to rest for at least 1 min, after which the excess solution was wicked
off using a filter paper. Atomic force microscopy (AFM) images were
obtained using a Park Systems NX10 instrument. Each sample used
for AFM measurements was dropped and spin-coated onto a freshly
cleaved mica surface. The nematic phases of the as-cast films were
observed using a Nikon Eclipse LV100 (Nikon, Tokyo, Japan). FT-IR
measurement was conducted using JASCO FT/IR-4700. A frequency-
doubled laser beam (repetition rate: 200 kHz, pulse duration: ∼250
fs) from a collinear optical parametric amplifier (COPA, Light
Conversion), which is pumped by a femtosecond regenerative
amplifier (PHAROS, Light Conversion), was used as a light source
for time-correlated single-photon counting (TCSPC) measurements.
Fluorescence from the sample after photoexcitation was spectrally
dispersed by a monochromator and then detected with a hybrid
photodetector (PMA Hybrid 50, PicoQuant). The TCSPC module
with picosecond event timer (PicoHarp 300, PicoQuant) was used to
record picosecond time-resolved fluorescence traces of the samples.
1. 3,5-Bis(decyloxy)benzaldehyde (7.03 g, 16.8 mmol) was
dissolved in pyrrole (500 mL), and trifluoroacetic acid (TFA, 0.5
mL, 6.53 mmol) was added to the solution. The reaction mixture was
stirred for 30 min at 60 °C. After the reaction, triethylamine (TEA,
0.5 mL, 3.58 mmol) was added to neutralize the solution. The
reaction mixture was chromatographed on silica gel using n-hexane
Dried THF (2 mL), TEA (3 mL), and trimethylsilylacetylene (0.18
mL, 1.27 mmol) were added. The reaction mixture was stirred for 12
h at 70 °C and then extracted with CH2Cl2 and distilled water. The
combined extract was concentrated and then purified by column
chromatography with CH2Cl2 and n-hexane to obtain 4 (260 mg) as a
1
reddish-purple solid in 50% yield. H NMR (400 MHz, CDCl3): δ =
9.76−8.85 (m, 8 H; pyrrole-β-H in PZn), 8.21−7.76 (m, 10 H; PZn-
C6H5), 7.4 (d, 2 H; o-H in PZn-C6H3), 6.84 (t, 1 H; p-H in PZn-C6H3),
4.08 (t, 4 H; −OCH2−), 1.82 (m, 4 H; −OCH2CH2−), 1.45−0.82
(m, 34 H, −(CH2)7CH3), 0.08 (s, 9 H, TMS-acetylene H). MALDI-
TOF-MS for C63H72N4O2SiZn m/z: calcd 1008.47, [M+]; found:
1008.25.
5. NaN3 (1.093 mg, 16.81 mmol) was added to a solution of 1,3,5-
tris(bromomethyl)benzene (1.0 g, 1.8 mmol) in 15 mL of an
acetone/H2O mixture (3:1, v/v). The resulting suspension was stirred
for 1 h at 25 °C, and the reaction mixture was extracted with CH2Cl2
and distilled water. The combined extract was evaporated to dryness.
1
5 (648 mg) was then obtained as a colorless liquid in 99% yield. H
NMR (400 MHz, CDCl3): δ = 7.25 (s, 3 H; C6H3), 4.40 (s, 6 H;
benzyl-H).
PZnT. CuSO4·5H2O (73.4 mg, 0.294 mmol), sodium ascorbate (58
mg, 0.29 mmol), KF (31 mg, 0.53 mmol), and 18-crown-6-ether (0.50
g, 1.9 mmol) were added to a mixture of 4 (175 mg, 0.176 mmol) and
5 (7.15 mg, 0.03 mmol) in 4.0 mL of THF/H2O (1:1, v/v). The
reaction mixture was stirred for 2 days at 70 °C and then extracted
with CH2Cl2 and distilled water. The combined extract was
evaporated and then purified by column chromatography with 30%
THF/n-hexane. Further purification was performed using recycling
SEC. The first fraction was collected from recycling SEC and then
recrystallized with THF and n-hexane to obtain PZnT (21 mg) as a
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purple solid in 23% yield. H NMR (400 MHz, THF-d8): δ = 9.29−
1
and CH2Cl2 to obtain 1 (6.5 g) as a yellow liquid in 72% yield. H
8.75 (m, 27 H; pyrrole-β-H in PZn and triazole-H), 8.09 (m, 12 H;
PZn-C6H5), 8.00 (s, 3 H; PZn-C6H3), 7.62−7.58 (m, 18 H; m- and p-H
in PZn-C6H5), 7.74−7.73 (d, 6 H; o-H in PZn-C6H3), 6.88 (s, 3 H; p-H
in PZn-C6H3), 6.23 (6 H; benzyl-H), 4.10 (t, 12 H; −OCH2−), 1.90−
0.83 (m, 114 H, −O(CH2)8CH3); 13C NMR (100 MHz, THF-d8) δ =
159.46, 151.76, 151.20, 151.13, 150.71, 150.36, 146.14, 144.64,
139.88, 135.47, 132.72, 132.43, 132.37, 132.06, 129.2, 128.53, 128.13,
127.24, 122.36, 121.59, 115.42, 101.38, 68.97, 54.49, 33.00, 30.76,
30.69, 30.58, 30.43, 27.27, 23.69, 14.58. MALDI-TOF-MS for
C189H201N21O6Zn3 m/z: calcd 3052.39, [M+]; found: 3055.83.
PFBT. PZnT was dissolved in CH2Cl2, and an excess of TFA was
then added to the solution. The mixture was stirred for 3 h at room
temperature. Ethylenediaminetetraacetic acid was added to remove
the zinc ions, and the reaction mixture was then extracted using
CH2Cl2 and aqueous sodium bicarbonate. The extract was purified by
column chromatography with CH2Cl2. PFBT was obtained in
quantitative yield. 1H NMR (400 MHz, CDCl3): δ = 9.05−8.69
(m, 24 H; pyrrole-β-H in PZn), 8.47 (s, 3 H; triazol-H), 7.92−7.35
(m, 39 H; overlapped peaks of PZn-C6H5 and o-H in PZn-C6H3), 6.87
(s, 3H; p-H in PZn-C6H3), 6.11 (s, 6 H; benzyl-H), 4.09 (t, 12 H;
−OCH2−), 2.02−0.83 (m, 114 H; −O(CH2)8CH3), −2.85 (s, 6H;
PFB-NH). MALDI-TOF-MS for C189H207N21O6 m/z: calcd 2866.65,
[M+]; found: 2869.65
NMR (400 MHz, CDCl3): δ = 7.94 (s, 2 H; −NH), 6.69 (m, 2 H;
C6H3), 6.37 (m, 2 H; H in a pyrrole ring), 6.36 (q, 1 H; C6H3), 6.34
(t, 2 H; H in a pyrrole ring), 5.96 (m, 2H; H in a pyrrole ring), 5.39
(s, 1 H; a-H of pyrrole), 3.88−3.84 (t, 4 H; −OCH2−), 1.76−1.69
(m, 4 H; −OCH2CH2−), 1.43−0.90 (m, 34 H; −(CH2)7CH3).
2. To a solution of 1 (1.62 g, 3.03 mmol), benzaldehyde (643 mg,
6.06 mmol), and dipyrromethane (443 mg, 3.03 mmol) in CH2Cl2
(900 mL), TFA (0.5 mL, 6.53 mmol) was added and stirred for 1.5 h
at 25 °C. p-Chloranil (4.47 g, 18.2 mmol) and TEA (0.5 mL, 3.59
mmol) were then added, and the reaction mixture was stirred for a
further 3 h. The reaction mixture was concentrated to a volume of 200
mL and then chromatographed on silica gel with n-hexane and
CH2Cl2. Without further purification, the mixture was dissolved in
10% MeOH/CH2Cl2 containing Zn(CH3CO2)2·2H2O (2 g, 9.11
mmol) and then stirred for 2 h at 25 °C. The reaction mixture was
purified by column chromatography with 3% ethyl acetate/n-hexane;
the second fraction was collected and evaporated to dryness. 2 (366
1
mg) was then obtained as a reddish-purple powder in 14% yield. H
NMR (400 MHz, CDCl3): δ = 10.24 (s, 1 H; meso-H in PZn), 9.39−
8.98 (m, 8 H; pyrrole-β-H in PZn), 8.24−7.77 (m, 10 H; PZn-C6H5),
7.39 (d, 2 H; o-H in PZn-C6H3), 6.88 (t, 1 H; p-H in PZn-C6H3), 4.1
(t, 4 H; −OCH2−), 1.85 (m, 4 H, −OCH2CH2−), 1.49−0.82 (m, 34
H; −(CH2)7CH3). MALDI-TOF-MS for C58H64N4O2Zn m/z: calcd
912.43, [M+]; found: 912.17.
3. N-Bromosuccinimide (122 mg, 0.685 mmol) was added to a
solution of 2 (619 mg, 0.677 mmol) in dry CH2Cl2 (60 mL), and the
solution was stirred under N2 for 15 min at 0 °C. The reaction
mixture was quenched with acetone (20 mL) and evaporated. The
mixture was chromatographed on silica gel using CH2Cl2 as the eluent
to obtain 3 (653.5 mg) as a purple solid in 97% yield. 1H NMR (400
MHz, CDCl3): δ = 9.69−8.88 (m, 8 H; pyrrole-β-H PZn), 8.19−7.76
(m, 10 H, PZn-C6H5), 7.30 (d, 2 H; o-H in PZn-C6H3), 6.82 (t, 1 H; p-
H in PZn-C6H3), 4.04 (t, 4 H; −OCH2−), 1.81 (m, 4 H;
−OCH2CH2−), 1.46−0.84 (m, 34 H, −(CH2)7CH3). MALDI-TOF-
MS for C58H63BrN4O2Zn m/z: calcd 990.34, [M+]; found: 992.30.
4. 3 (502 mg, 0.505 mmol), CuI (1.92 mg, 0.01 mmol), and
Pd(PPh3)2Cl2 (7.09 mg, 0.01 mmol) were placed in a Schlenk flask.
The flask was degassed under high vacuum and back-filled with N2.
TB. Azidomethyl benzene (406 mg, 3.05 mmol), 1-pentyne (208
mg, 3.05 mmol), CuSO4·5H2O (973 mg, 3.90 mmol), and sodium
ascorbate (1.21 g, 6.10 mmol) were dissolved in 25 mL of THF/H2O
(4:1, v/v). The reaction mixture was stirred overnight at room
temperature and then extracted with CH2Cl2 and distilled water. The
extract was purified by column chromatography with ethyl acetate and
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n-hexane. TB (580 mg) was obtained in 94% yield. H NMR (400
MHz, MeOD): δ = 7.70 (s, 1H; triazole-H), 7.37−7.29 (m, 5H;
C6H5), 5.54 (s, 2H; benzyl-H), 2.67−2.63 (t, 2H; −CH2CH2CH3),
1.71−1.62 (m, 2H; −CH2CH2CH3), 0.96−0.92 (t, 3H;
−(CH2)2CH3).
Py3B. [1,1′-Bis(diphenylphosphino)ferrocene]dichloro-palladium-
(II) (80 mg, 1.1 mmol) and Na2CO3 (1.60 g, 15.1 mmol) were
added to a solution of 1,3,5-tribromobenzene (157 mg, 0.5 mmol)
and 4-pyridineboronic acid (250 mg, 2.03 mmol) in 40 mL of 1,4-
dioxane/H2O (1:1, v/v). The mixture was degassed by bubbling a N2
C
Macromolecules XXXX, XXX, XXX−XXX