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Polymer PFTH50 prepared as a yellow solid in 76% yield.
Mn 5 20,100, PDI 5 2.6. Tg 78 8C. 1H-NMR (100 MHz, CDCl3,
d): 7.79–7.66 (m, 12H, aromatic), 7.57–7.43 (m, 12H, aromat-
ic), 7.36–7.22 (m, 6H, aromatic), 7.16–6.92 (m, 3H, aromatic),
2.80 (s, 3H, aliphatic), 1.09–1.02 (m, 40H, aliphatic), 0.75–
0.73 (m, 12H, aliphatic). 13C-NMR (100 MHz, CDCl3, d m):
163.95, 152.64, 147.52, 146.85, 146.56, 141.13, 140.06,
139.36, 135.97, 132.53, 131.86, 130.88, 129.31, 128.80,
127.90, 125.42, 124.62, 123.71, 121.01, 119.17, 55.20, 40.42,
31.52, 29.76, 23.77, 22.61, 19.31, 14.00.
of polymer was measured in a minute after mixing. The
emission spectra of polymer before and after cation or anion
addition were compared.
For fluorescence titration experiments, in case of Fe21 and
Hg21, three aqueous stock solutions 1022, 1023, and 1024
M
were prepared. About 3 mL of polymer’s solution (20 lg/
mL) in THF were added in a cuvette. Aliquot of the appropri-
ate stock solution was added so as the concentration of the
cations in polymer solution gradually increased from 1 to
800 lM.
Polymer PFTH25 prepared as a yellow solid in 59% yield.
Mn 5 22,500, PDI 5 1.8. Tg 90 8C. 1H-NMR (100 MHz, CDCl3, d):
7.79–7.60 (m, 12H, aromatic), 7.50–7.26 (m, 12H, aromatic),
7.17–6.96 (m, 9H, aromatic), 2.78 (s, 3H, aliphatic), 1.11–1.01
(m, 40H, aliphatic), 0.76–0.73 (m, 12H, aliphatic). 13C-NMR (100
MHz, CDCl3, d): 163.98, 151.73, 147.58, 146.91, 146.55, 141.21,
139.83, 139.37, 135.95, 132.55, 132.11, 130.02, 129.48, 128.51,
127.89, 125.60, 124.59, 124.30, 123.46, 120.97, 119.96, 55.26,
40.54, 31.50, 29.73, 23.84, 22.60, 19.31, 14.02.
RESULTS AND DISCUSSION
Monomers Synthesis
Scheme 1 shows the method for the preparation of mono-
mers TH and OX. These monomers were derivatives of thia-
zole and oxazole and they were used as starting materials
for the preparation of polymers. They were synthesized via a
multistep procedure. The key step for the synthesis of TH
and OX derivatives was the preparation of a-bromo ketone 2.
It was prepared by bromination of ketone 1. The condensa-
tion of 2 with thioacetamide gave TH. On the other hand, 2
reacted with sodium acetate to give keto-ester 3. The later
was condensated48 with CH3COONH4 to give OX. The mono-
Polymer PFOX100 prepared as a yellow solid in 79% yield.
Mn 5 10,700, PDI 5 2.5. Tg 55 8C. 1H-NMR (400 MHz, CDCl3,
d): 7.78–7.70 (m, 4H, aromatic), 7.65–7.52 (m, 4H, aromatic),
7.45–7.25 (m, 6H, aromatic), 2.57 (s, 3H, aliphatic), 1.09–1.00
(m, 20H, aliphatic), 0.75–0.72 (m, 6H, aliphatic). 13C-NMR
(100 MHz, CDCl3, d): 160.44, 149.68, 146.35, 143.29, 140.08,
139.65, 132.70, 131.90, 129.42, 127.93, 127.47, 126.46, 55.06,
40.36, 31.53, 29.76, 23.76, 22.65, 15.12, 14.01.
mers were characterized by FT-IR, H-NMR, 13C-NMR as well
as elemental analysis.
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Polymers Synthesis and Characterization
The monomers TH and OX were used as starting materials
for the preparation of polymers via Suzuki coupling. Two
series of polyfluorenes containing thiazole or oxazole as well
as triphenylamine (TPA) moieties were prepared. In poly-
mers’ names TH or OX stands for thiazole or oxazole, respec-
tively, while numbers 100, 50, and 25 indicate the ratio of
thiazole or oxazole in polymer chain, relative to TPA. More
particularly, Suzuki coupling of TH and 4,4’-dibromotriphe-
nylamine with 9,9-dihexylfluorene-2,7-diboronic acid bis(1,3-
propanediol) ester gave polymers PFTH100, PFTH50, and
PFTH25 (Scheme 2). These polymers differ in the content of
thiazole moieties which was achieved by changing the feed
ratio of dibromides TH/4,4’-dibromotriphenylamine. In the
same way, polymers PFOX100, PFOX50, and PFOX25
(Scheme 3), containing oxazole moieties, prepared by Suzuki
coupling of dibromides OX/4,4’-dibromotriphenylamine with
9,9-dihexylfluorene-2,7-diboronic acid bis(1,3-propanediol)
Polymer PFOX50 prepared as a yellow solid in 56% yield.
Mn 5 13,500, PDI 5 3.1. Tg 42 8C. 1H-NMR (400 MHz, CDCl3,
d): 7.77–7.65 (m, 12H, aromatic), 7.59–7.43 (m, 12H, aromat-
ic), 7.34–7.25 (m, 6H, aromatic), 7.06–6.92 (m, 3H, aromatic),
2.56 (s, 3H, aliphatic), 1.09–0.99 (m, 40H, aliphatic), 0.75–
0.72 (m, 12H, aliphatic). 13C-NMR (100 MHz, CDCl3, d):
160.42, 150.32, 146.57, 143.54, 140,64, 136.38, 135.91,
134.55, 132.34, 131.91, 129.54, 129.39, 128.62, 127.94,
127.88, 127.45, 125.41, 124.61, 123.75, 121.02, 54.90, 40.38,
31.52, 29.76, 23.77, 22.65, 15.12, 14.01.
Polymer PFOX25 prepared as a yellow solid in 81% yield.
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Mn 5 16,700, PDI 5 3.7. Tg 5 61 8C. H-NMR (400 MHz, CDCl3,
d): 7.76–7.74 (m, 8H, aromatic), 7.67–7.54 (m, 8H, aromatic),
7.47–7.22 (m, 8H, aromatic), 7.15–6.92 (m, 9H, aromatic),
2.57 (s, 3H, aliphatic), 1.10–1.05 (m, 40H, aliphatic) 0.76–0.74
(m, 12H, aliphatic). 13C-NMR (100 MHz, CDCl3, d): 160.58,
149.91, 146.9, 144.41, 140,57, 136.36, 135.96, 134.42, 132.35,
132.25, 132.17, 129.60, 129.45, 128.81, 128.49, 127,98,
127.90, 127.22, 125.33, 124.62, 124.38, 121.05, 55.35, 40.52,
31.49, 29.74, 23.83, 22.59, 15.08, 14.01.
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ester. The polymers’ structures were verified by H-NMR and
13C-NMR spectroscopy. Molecular weights were determined
by GPC and the Mn range from 10,700 to 22,500. All these
data are shown in “Experimental” section.
All polymers were readily soluble in organic solvents such as
dichloromethane, chloroform, and THF. Polymer solutions
with concentration up to 2% were prepared. Transparent
and pinhole-free films were formed by casting polymers’ sol-
utions. Thermal properties of polymers were investigated by
DSC. The Tg of polymers were determined from second heat-
ing scan and range from 42 to 90 8C (see “Experimental”
section). The rather low Tg should be attributed to the
Fluorescence Titration Experiments
Fluorescence experiments were carried out in a 1 3 1 cm
quartz cuvette. The emitted light was collected 908 relative
to excitation beam. To examine polymers chemosensing
properties, an aliquot of a 1022 M aqueous stock solution of
cation or anion was added to a solution of polymer (20 lg/
mL) in THF to obtain final concentration 100 lM. Emission
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JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2016, 00, 000–000