Synthesis of n-type π-conjugated polymers with pendant crown ether and their stability of n-doping state against air

Article abstract of DOI:10.1021/ma101731v

The n-type π-conjugated polymers with a 1,2,4-triazole ring substituted by a benzo-15-crown-5-ether (benzo15C5) subunit at the 4-position of the 1,2,4-triazole ring were synthesized by organometallic polycondensations. The UV-vis spectra of the polymers e

Full text of DOI:10.1021/ma101731v

9348 Macromolecules 2010, 43, 9348–9354
DOI: 10.1021/ma101731v
Synthesis of n-Type π-Conjugated Polymers with Pendant Crown Ether
and Their Stability of n-Doping State against Air
Isao Yamaguchi* and Hidehito Mitsuno
Department of Material Science, Faculty of Science and Engineering, Shimane University,
1060 Nishikawatsu, Matsue 690-8504, Japan
Received July 30, 2010; Revised Manuscript Received October 4, 2010
ABSTRACT: The n-type π-conjugated polymers with a 1,2,4-triazole ring substituted by a benzo-15-crown-
5-ether (benzo15C5) subunit at the 4-position of the 1,2,4-triazole ring were synthesized by organometallic
polycondensations. The UV-vis spectra of the polymers exhibited absorption maxima (λmax values) at
a longer wavelength than that exhibited by 4-benzo15C5-1,2,4-triazole (model-1), revealing that their
π-conjugation system was expanded along the polymer chain. The electric conductivity measurements
suggested that model-1 formed inclusion adducts with 1:1 and 2:1 molar ratios with Naþ and Kþ, respectively.
Addition of KClO4 to the DMSO solutions of the polymers with the benzo15C5 subunit caused the formation
of the 2:1 inclusion between the 15C5 ring and Kþ; this inclusion led to a bathochromic shift in λmax of the
polymers. In addition, photoluminescence intensity of the polymers decreased after the addition of KClO4 to
solution. The polymers with the benzo15C5 subunit underwent an electrochemical reduction (n-doping), and
the corresponding oxidation (n-dedoping) occurred at an unusually high potential in an acetonitrile solution
of NaClO4; the factor responsible for the unusually high oxidation potential was the stabilized n-doping state
that was attributed to the inclusion of Naþ in the 15C5 ring. The electric conductivities of the polymers were
increased by n-doping with sodium naphthalenide. The polymers with the benzo15C5 subunit exhibited a
considerably higher stability of the n-doping state in air than did those without this subunit.
Introduction
that n-type π-conjugated polymers with a CE subunit will exhibit
a stable n-doping state in air when they are doped with alkaline
π-Conjugated polymers have attracted considerable attention
due to their interesting chemical properties and practical
applications.1 For example, they can undergo a reductive (n-type)
or an oxidative (p-type) doping that effectively converts them
into conducting materials.1 However, reports on n-type conductive
polymers are considerably less than those on p-type ones because
of the difficulty associated with synthesizing n-type π-conjugated
polymers and their low solubility in organic solvents.2 Further,
n-doping of π-conjugated polymersis carried outby treatingthem
with alkaline metals such as sodium and potassium and subse-
quently applying them an adequate potential so as to cause their
electrochemical reduction.3,4 However, the n-doping state of
π-conjugated polymers is usually unstable in air because the re-
duced polymer chain and countercations (usually alkaline metal
ions) undergo oxidation with atmospheric O2. These situations
make it difficult to investigate the chemical properties of n-doped
π-conjugated polymers and consequently restrict their utilization
for industrial applications.
It was reported that polythiophene with a crown ethereal
subunit (PTh-CE) exhibited a stable n-doping state in air when
the polymer was doped with Na; this is in contrast to the fact that
the n-doping state of PTh without a CE subunit is instable in air.5,6
The stability of the n-doping state in PTh-CE is attributed to the
fact that a dopant cation (Naþ) was captured in the CE subunit
of PTh-CE during n-doping. In other words, the inclusion of
Naþ in the CE subunit prevents the disassociation of Naþ from
the reduced polymer chain and the consequent oxidation of the
reduced polymer chain. In addition, p-type π-conjugated poly-
mers with a CE subunit were applied for sensors that targeted
alkaline metals, enzymes, and amino acids.7 Further, it is expected
metals; this is because the dopant cation (alkaline metal ion) can
be included in the CE subunit. This situation makes it easy to
investigate the chemical and electrical properties of n-type
π-conjugated polymers after n-doping. However, to the best
of our knowledge, there has been no report on an n-type
π-conjugated polymer with a CE subunit. In this study, the
electrical and optical properties of n-type π-conjugated poly-
mers with a CE subunit were investigated before and after
n-doping with sodium naphthalenide in order to obtain
fundamental information for the development of new con-
ductive materials. π-Conjugated polymers with triazole rings
should exhibit n-type electrical properties because 1,3,4-
triazoles are π-electron-deficient compounds. In the present
study, with the aim of obtaining the desired polymers, a new
monomer, 3,5-bis(4-bromophenyl)-1,2,4-triazole with a ben-
zo-15-crown-5-ether (benzo15C5) group at the 4-position of
the triazole ring, was synthesized and polymerized using
Ni(0)-complex-promoted dehalogenation, Pd-complex-cata-
lyzed Suzuki-type reactions, or Sonogashira-type reactions.
Herein, we report the synthesis of n-type π-conjugated poly-
mers with and without the benzo15C5 subunit and their optical,
electrochemical, and electric properties before and after n-doping
with sodium naphthalenide. In addition, a water-soluble model
compound, 4-benzo15C5-1,2,4-triazole, was synthesized to
investigate the inclusion behavior of alkaline metal ions and
compare its chemical properties with those of the polymers.
Results and Discussion
Synthesis. Monomers with a 3,5-bis(4-bromophenyl)-1,2,
4-triazole ring substituted by benzo15C5 or by 4-methoxyphe-
nyl groups (monomer-1 and monomer-2) were synthesized
*Corresponding author. E-mail: iyamaguchi@riko.shimane-u.ac.jp.
pubs.acs.org/Macromolecules
Published on Web 10/22/2010
r 2010 American Chemical Society

Article
Macromolecules, Vol. 43, No. 22, 2010 9349
Scheme 1. Synthesis of Monomers and a Model Compound
Scheme 2. Synthesis of π-Conjugated Polymers with Pendant 15C5 Groups
through the 2:1 reaction of 4-bromobenzoyl chloride with
hydrazine monohydrate and the following ring-closure reac-
tion with 40-aminobenzo-15-crown-5-ether or 4-aminoanisole,
respectively (Scheme 1a). A model compound with the ben-
zo15C5 group at the 4-position of a 1,2,4-triazole ring (model-1)
was synthesized by the reaction of 1,2-diformylhydrazine with
40-aminobenzo-15-crown-5-ether by using p-hydroquinone as
a reduction agent (Scheme 1b).
π-Conjugated polymers with and without a pendant ben-
zo15C5 subunit were synthesized by organometallic poly-
condensations, as shown in Scheme 2. Dehalogenation
polycondensation of monomer-1 and monomer-2 carried
out using Ni(cod)2 (cod = 1,5-cyclooctadiene) as a conden-
sation reagent afforded polymer-1 and polymer-2 in 95%
and 87% yields, respectively. Pd-complex-catalyzed poly-
condensation of monomer-1 and monomer-2 with 2,6-dioc-
tyloxybenzene-1,4-diboronic acid or 1,4-diethynylbenzene
resulted in 98%, 81%, 78%, and 99% yields for polymer-3,
polymer-4, polymer-5, and polymer-6, respectively. The
synthesis results are summarized in Table 1.
(DMSO) at 100 °C but was insoluble in polar organic solvents
and nonpolar organic solvents such as chloroform and toluene
at room temperature. On the other hand, polymer-2 was
slightly soluble in DMSO at 120 °C. Polymer-3 was partly
soluble in chloroform, but polymer-4 was slightly soluble in
the solvent. The solubilities of polymer-1 and polymer-3 were
higher than those of polymer-2 and polymer-4 because of the
presence of the 15C5 rings in polymer-1 and polymer-3.
However, polymer-5 and polymer-6 were insoluble in organic
solvents, probably because of their stiff structures. Model-1
was soluble in water and organic solvents such as chloroform,
DMF, and DMSO.
The Mn and Mw values of the obtained polymers, deter-
mined by GPC measurements, are summarized in Table 1.
The Mn and Mw values of the DMF-soluble part of polymer-1
were 13 700 and 14 400, respectively, while those of the
chloroform-soluble part of polymer-3 and polymer-4 were
5100 and 10 200 and 5100 and 12 200, respectively. The
molecular weights of the other polymers could not be
determined because of their insolubility.
Polymer-1 was partly soluble in polar organic solvents such
as N,N-dimethylformamide (DMF) and dimethyl sulfoxide
IR and 1H NMR Spectra. Figure 1 shows the IR spectra of
monomer-1, polymer-1, polymer-3, and polymer-5. The peak

9350 Macromolecules, Vol. 43, No. 22, 2010
Yamaguchi and Mitsuno
Table 1. Synthesis Results and Chemical Properties of the Obtained Polymers and Model Compound
reduction potential/Vh electric conductivity/S cm-1
em/nmf
Epc
Epc
nondoped
Na-dopedi
a
a
yield (%)
Mn
Mw
absorption/nm
λ
polymer-1
polymer-2
polymer-3
polymer-4
polymer-5
polymer-6
model-1
95
87
98
81
78
99
23
13700b
14400b
;
332e
391, 406 (0.35)e
404 (0.18)e
414 (0.20)c
412 (0.27)c
406, 424g
-2.37
-2.27
-2.23
-2.35
0.08
-0.91
0.11
2.1 ꢁ 10-7
6.2 ꢁ 10-7
7.2 ꢁ 10-8
1.1 ꢁ 10-7
3.1 ꢁ 10-7
5.7 ꢁ 10-7
5.0 ꢁ 10-4
6.1 ꢁ 10-4
5.6 ꢁ 10-4
5.6 ꢁ 10-4
6.1 ꢁ 10-4
5.0 ꢁ 10-4
d
d
;
318e
5100c
5100c
10200c
12200c
;
293, 347c
299, 346c
;
-0.84
;
;
d
d
d
d
d
;
;
;
d
d
d
d
;
d
;
;
406, 424g
241, 282e
355 (0.0034)e
a Determined by GPC (vs polystyrene standards). b DMF-soluble part. c CHCl3-soluble part. d Not measured due to insolubility in the eluent.
e DMSO-soluble part. f Quantum yields of photoluminescence are shown in parentheses. g In solid state. h Measured by cyclic voltammetry in an
acetonitrile solution of NaClO4 (0.10 M). i Measured immediately after preparation of the sample under nitrogen.
Figure 1. IR spectra of monomer-1, polymer-1, polymer-3, and
polymer-5.
corresponding to the stretching vibrations of a C-Br bond is
Figure 2. 1H NMR spectra of monomer-1 and polymer-1 in DMSO-d6
and that of polymer-3 in CDCl3.
observed at 1071 cm-1 in the IR spectrum of monomer-1,
whereas it disappeared in the IR spectra of polymer-1, poly-
mer-3, and polymer-5. The disappearance suggests that the
expected polycondensations occurred. Further, instead of the
stretching vibrations of the C-Br and ꢀC-H bonds, a new
peak corresponding to the stretching vibrations of a disubsti-
tuted CtC bond appears at 2207 cm-1 in the IR spectrum of
polymer-5. These observations correspond to the fact that the
peak corresponding to the terminal groups of polymer-5
disappears because of the high molecular weight of this poly-
mer. The appearance of the absorption corresponding to
ν(O-H) around 3500 cm-1 in the IR spectra of the polymers
suggests that they contain hydrated water molecule(s). The
analytical and TGA data of the polymers also support the
hydration (see Figure S2).
peak assignments are indicated in the figure. The signals
corresponding to the aromatic (Ha-He) and crown ethereal
(Hf-Hm) protons of polymer-1 are observed in the ranges
δ 6.89-7.70 and δ 3.53-4.11, respectively, while those
corresponding to the aromatic (Ha-He, Hn) protons, crown
ethereal (Hf-Hm), and OCHo protons of octyloxy and
2
octyloxy (Hp-Hr) protons of polymer-3 are observed in
the ranges δ 6.77-7.57, δ 3.75-4.18, and δ 0.87-1.70,
respectively. The relative peak integral ratio supports the
structures shown in Scheme 2.
Inclusion of Alkaline Metals. In order to investigate the
inclusion behavior of alkaline metals in the benzo15C5 ring of
model-1, electric conductivity measurements of an aqueous
solution of model-1 were carried out when limited amounts of
1
Figure 2 shows the H NMR spectra of monomer-1 and
polymer-1 in DMSO-d6 and that of polymer-3 in CDCl3. The

Article
Macromolecules, Vol. 43, No. 22, 2010 9351
Figure 4. UV-vis spectra of monomer-1 in DMSO, polymer-1 in
DMSO, and polymer-3 in chloroform.
Figure 3. Conductivity changes of an aqueous solution of model-1
(2.0 mmol/L) by addition of NaClO4 (a) and KClO4 (b) in amounts of
every 0.20 mmol.
aqueous solutions of NaClO4 and KClO4 were added to the
solution. Figure 3 shows the measurement results. The con-
ductivities of the model-1 solution slightly increase until the
addition of an equimolar amount of NaClO4 and then sharply
increase after the equivalence point. On the other hand, the
conductivities of the model-1 solution slightly increase until the
addition of an half equimolar amount of KClO4 and then
sharply increase after the point corresponding to the half
equimolar amount. These results suggest that model-1 formed
1:1 and 2:1 inclusion adducts with Naþ and Kþ, respectively.
This suggestion seems valid considering that 15C5 can form 1:1
and 2:1 inclusion adducts with Naþ and Kþ, respectively.8
UV-vis and Photoluminescence Spectra. Optical data are
summarized in Table 1. Figure 4 shows the UV-vis spectra of
monomer-1 in DMSO, polymer-1 in DMSO, and polymer-3 in
chloroform. The absorption maxima (λmax values) of polymer-1
and polymer-3 were longer than that of monomer-1, suggest-
ing that the π-conjugation system was expanded along the
polymer chain. It has been reported that the two phenyl
substituents at the 3- and 5-positions of a 1,2,4-triazole ring
are twisted by approximately 90° toward the plane of the
triazole ring.9 This twisting angle is larger than that between
the two p-phenylene rings in oligo( p-phenylene).10 According
to these reports, the fact that the λmax value of polymer-3 is
larger than that of polymer-1 is attributed tothe presence of the
dioctyloxybenzene spacing group between the two p-phenyl-
ene rings in polymer-3; this group reduces the twisting of the
main chain of this polymer.
Figure 5 shows the UV-vis spectra of model-1 in water and
polymer-1 in DMSO before and after the addition of excess
amounts of NaClO4 or KClO4. The UV-vis spectra of the
solutions of model-1 and polymer-1 were almost unchanged
after the addition of NaClO4. However, after the addition
of KClO4, the λmax values of the solutions of model-1 and
polymer-1 shifted to longer wavelengths by 22 and 10 nm,
respectively. The bathochromic shift of model-1 and polymer-1
after the addition of KClO4 is apparently due to the π-stacking
in model-1 and polymer-1, which is attributed to the 1:2 inclu-
sion between Kþ and the 15C5 ring in model-1 and polymer-1.
The above-mentioned electric conductivity measurements of
model-1 support the 1:2 inclusion between Kþ and the 15C5
ring. The fact that the bathochromic shift of polymer-1 was
smaller than that of model-1 corresponds to the assumption
Figure 5. UV-vis spectra ofmodel-1 inwater and polymer-1 in DMSO
before and after the addition of excess amounts of NaClO4 or KClO4.
that in polymer-1 the π-stacking caused by the inclusion
between Kþ and the 15C5 ring occurred partly.
Monomer-1, model-1, and the polymers obtained in this
study were photoluminescent in solution and in the solid
state. The emission peak positions of polymer-1, polymer-2,
polymer-3, and polymer-4 were longer than those of monomer-1
and model-1 in solution. These observations are consistent
with the results that the λmax values of polymer-1, polymer-2,
polymer-3, and polymer-4 were larger than those of monomer-1
and model-1. The PL peaks of the polymers appear at the onset
position of their absorption bands, as usually observed with
photoluminescent aromatic compounds. The quantum yields
(Φ values) of the PL of polymer-1, polymer-2, polymer-3, and
polymer-4 were 0.35, 0.18, 0.20, and 0.18, respectively; these Φ
values were considerably larger than that of monomer-1 (Φ =
0.003). Further, the PL peak intensity of polymer-1 in DMSO
decreased after the addition of KClO4 to the solution. This
decrease in the PL was apparently attributed to the π-stacked
structure of the polymer that was formed by the 1:2 inclusion
between Kþ and the 15C5 ring in the polymer. This attribu-
tion is consistent with a reported result that the PL intensity
of π-conjugated polymers decreased when they formed the
π-stacking structures.11 The PL measurements of polymer-5
and polymer-6 were carried out in the solid state because of
their insolubility in organic solvents. Both polymer-5 and
polymer-6 exhibited a PL peak at 406 nm. This wavelength
was comparable to the PL peak wavelengths of polymer-1 and
polymer-2.

9352 Macromolecules, Vol. 43, No. 22, 2010
Yamaguchi and Mitsuno
Figure 7. Changes of electric condþuctivity of the n-doped polymer-1
(black solid curve), polymer-1(Na ) (green solid curve), polymer-2
(black dotted curve), polymer-3 (blue solid curve), polymer-4 (blue
dotted curve), polymer-5 (red solid curve), and polymer-6 (red dotted
curve) when they were allowed to stand in air.
THF. TheirelectricconductivitiesaresummarizedinTable1.
The n-doped polymers exhibited electric conductivities that
were ∼103 times higher than those of the respective non-
doped polymers. The electric conductivity of the n-doped
polymers decreased with time when they were allowed to
stand in air, as shown in Figure 7.
Figure 6. Cyclic voltammograms of cast films of polymer-1 (a) and
polymer-3 (b) in an aqueous solution containing NaClO4 (0.10 M) (red
curve) and an acetonitrile solution containing [Et4N]BF4 (0.10 M) (blue
curve).
This is because the reduced polymers are dedoped by
oxidation in air. The electric conductivities of n-doped
polymer-1, polymer-3, and polymer-5 with benzo15C5
groups decreased gradually and attained almost the 100
times higher values than those of the corresponding non-
doped polymers after 6 h when the n-doped polymers were
exposed to air. In contrast, the electric conductivities of
n-doped polymer-2, polymer-4, and polymer-6 without ben-
zo15C5 groups decreased rapidly and attained the same
values as those of the corresponding nondoped polymers
after 6 h when these n-doped polymers were exposed to air.
The gradual decease in the electric conductivities of n-doped
polymer-1, polymer-3, and polymer-4 in air corresponds to
their stabilized n-doping state that originated from the
inclusion of Naþ in their 15C5 ring. This view is consistent
with the above-mentioned CV results. However, the n-doped
polymers may contain a site at which the inclusion of Naþ
in their 15C5 ring did not occur because the n-doping was
carried out in the THF suspension of the polymers and
sodium naphthalenide. Increasing the number of such sites
in the n-doped polymers will lead to a further improvement
in the stability of the polymer’s n-doping state against
exposure to air. In order to confirm this hypothesis, poly-
mer-1 was treated with a DMSO solution of NaClO4 to
obtain polymer-1(Naþ) before n-doping, and changes in the
electric conductivity of n-doped polymer-1(Naþ) were in-
vestigated when it was allowed to stand in air. As shown in
Figure 7, n-doped polymer-1(Naþ) exhibited improved sta-
bility of the n-doping state against air, as expected; the
electric conductivity of polymer-1(Naþ) when it was exposed
to air for 6 h was 3 times higher than that of n-doped
polymer-1 when the latter was allowed to stand in air for
6 h. These results confirmed that the inclusion of Naþ in the
pendant 15C5 rings of the polymers was responsible for the
improved stability of the n-doped polymers against air.
Cyclic Voltammograms. Figure 6 shows the cyclic voltam-
mograms of cast films of polymer-1 and polymer-3 in an
aqueous solution containing NaClO4 (0.10 M) and an aceto-
nitrile solution containing [Et4N]BF4 (0.10 M). Polymer-1
and polymer-3 exhibited a peak at -2.37 V (vs Agþ/Ag) and
-2.23 V (vs Agþ/Ag) corresponding to the electrochemical
reduction of the triazole ring in the aqueous solution of
NaClO4, respectively. The observation that the reduction
potential of polymer-3 is more positive than that of polymer-1
is consistent with the fact that the π-conjugation system
of polymer-3 is larger than that of polymer-1. The correspond-
ing oxidation (n-dedoping) peaks of polymer-1 and polymer-3
were observed at 0.14 V (vs Agþ/Ag) and 0.11 V (vs Agþ/Ag),
respectively. The large difference between the reduction and
oxidation potentials is attributed to the strong interaction
of polymer-1 and polymer-3 with Naþ. That is, Naþ was
captured by the 15C5 ring of the reduced polymer-1 and
polymer-3 at -2.37 V (vs Agþ/Ag) and -2.23 V (vs Agþ/
Ag), respectively. The n-doped state thus formed is considered
to be stabilized, and its oxidation (or n-dedoping) is considered
to require a much higher potential than the n-doping potential.
This assumption is supported by the result that the elec-
trochemical reduction and the corresponding oxidation
(n-dedoping) peaks of polymer-2 and polymer-4 in an aceto-
nitrile solution of NaClO4 were observed at -2.27 V (vs Agþ/Ag)
and -0.91 V (vs Agþ/Ag) and -2.35 V (vs Agþ/Ag) and
-0.72 V (vs Agþ/Ag), respectively. The above assumption is
also supported by the result that the cyclic voltammogram of
the cast film of polymer-1 in the aqueous solution containing
NaClO4 (0.10 M) obtained by scanning in a range of -1.5 V
(vs Agþ/Ag) to 2.2 V (vs Agþ/Ag) did not exhibit both the
n-doping and n-dedoping peaks. A similar exceptionally high
potential for n-dedoping was observed in the case of PTh with
a crown ethereal subunit: the polymer underwent electrochem-
ical reduction (n-doping) at -2.2 V (vs Agþ/Ag) and the
corresponding oxidation (n-dedoping) at 0.2 V (vs Agþ/Ag).6c
Electric Conductivity. n-Doping of the polymers was
carried out by treating them with sodium naphthalenide in
Conclusion
π-Conjugated polymers with the benzo15C5 subunit at the
4-position of a 1,2,4-triazole ring were synthesized by Ni(0)-
complex-promoted dehalogenation and Pd-complex-catalyzed

Article
Macromolecules, Vol. 43, No. 22, 2010 9353
Suzuki- and Sonogashira-type polycondesations. Inclusion of
alkaline metal ions in the 15C5 ring of the polymers affected their
optical properties; the λmax position of the polymers shifted to a
longer wavelength, and the photoluminescence intensity of the
polymers decreased when the 15C5 ring include Kþ in solution.
The cast films of polymers underwent an electrochemical reduc-
tion (n-doping), and because of the stabilized n-doping state, they
required an exceptionally high potential for n-dedoping. The
polymers with the benzo15C5 subunits exhibited a higher stabil-
ity of the n-doping state in air as compared to those without
benzo15C5 subunits. From the results obtained in this study, it
can be concluded that new air-stable n-type conductive materials
can be developed on the basis of the ability of crown ether rings in
n-type π-conjugated polymers to be an accepting site for a dopant
alkaline metal ion.
2.4 mmol), and p-hydroquinone (0.11 g, 1.0 mmol) was melted at
170 °C and stirred at the temperature for 5 h. Afterward, the
mixture was cooled to room temperature and washed with ether
(100 mL). The ether-insoluble part was collected by filtration,
dissolved in water, and extracted with chloroform. The solvent
was removed under vacuum and dissolved in 3 mL of chloro-
form. The solution was poured in ether, and the resulting
precipitate was collected by filtration and dried under vacuum
to give model-1 as a light brown powder (0.19 g, 23%). 1H NMR
(400 MHz, DMSO-d6): δ 9.04 (s, 2H), 7.31 (d, J = 2.8 Hz, 1H),
7.19 (dd, J = 2.4 and 7.6 Hz, 1H), 7.40 (d, J = 8.8 Hz, 1H), 4.15
(m, 2H), 4.09 (m, 4H), 3.79 (m, 4H), 3.62 (s, 8H). 13C NMR (100
MHz, DMSO-d6): δ 149.2, 148.1, 141.5, 127.4, 114.2, 113.4,
107.6, 70.5, 69.7, 68.7. Calcd for C16H21N3O5 0.1H2O: C, 57.00;
H, 6.34; N, 12.46. Found: C, 56.80; H, 6.32; N, 12.13. Mp =
162-163 °C.
3
Synthesis of Polymer-1. Ni(cod)2 (0.10 g, 0.37 mmol), 2,2-
bipyridyl (0.058 g, 0.37 mmol), and cod (46 μL, 0.37 mmol) were
dissolved in 7 mL of dry DMF under nitrogen. To the solution
was added an DMF solution (3 mL) of monomer-1 (0.20 g, 0.31
mmol) at 60 °C. The reaction solution was stirred at 85 °C for
72 h. The precipitate was collected by filtration, washed with an
aqueous solution of ammonia (three times), and dried under
vacuum to give polymer-1 as a brown powder (0.14 g, 95%). 1H
NMR (400 MHz, DMSO-d6): δ 7.68 (4H), 7.55 (4H), 6.89-7.48
(3H), 4.11 (2H), 3.97 (2H), 3.77 (2H), 3.53-3.61 (10H). Calcd
Experimental Section
General. Solvents were dried, distilled, and stored under nitro-
gen. N,N0-Bis[chloro(p-bromophenyl)methylene]hydrazine and
2,5-dioctyloxy-1,4-benzenediboronic acid were synthesized ac-
cording to the reported manner.12,13 Other reagents were pur-
chased and used without further purification. Reactions were
carried out with standard Schlenk techniques under nitrogen.
IR and NMR spectra were recorded on a JASCO FT/IR-660
PLUS spectrophotometer with a KBr pellet and a JEOL AL-400
spectrometer, respectively. Elemental analysis was conducted
on a Yanagimoto MT-5 CHN corder. GPC analyses were
carried out by a Toso HLC 8020 with polystyrene gel columns
(TSKgel G2000HHR and TSKgel GMHHR-M) using a DMF
solution of LiBr (0.006 M) as an eluent with RI and UV
detectors and a Jasco 830 refractometer with polystyrene gel
columns (K-803 and K-804) using chloroform as an eluent with
a RI detector. UV-vis and PL spectra were obtained by a
JASCO V-560 spectrometer and a JASCO FP-6200, respec-
tively. Quantum yields were calculated by using a diluted
ethanol solution of 7-(dimethylamino)-4-methylcoumarin as
the standard. Cyclic voltammetry was performed in a DMSO
solution containing 0.10 M [Et4N]BF4 with a Hokuto Denko
HSV-110. Electric conductivity measurements in aqueous solu-
tion and solid state were conducted by a Horiba Cond Meter
ES-51 and an Advantest R8340A ultrahigh-resistance meter
with a two-probe method, respectively.
for (C28H21N3O5 H2O)n: C, 67.60; H, 4.66; N, 8.45. Found:
3
C, 67.88; H, 4.90; N, 8.12.
Polymer-2 was synthesized analogously.
Data of Polymer-2. 1H NMR (400 MHz, DMSO-d6): δ 7.73
(2H), 7.41-7.48 (8H), 7.03 (2H), 3.79 (3H). Calcd for
(C21H15N3O 2H2O)n: C, 69.79; H, 5.30; N, 11.63. Found:
C, 69.57; H, 5.02; N, 11.40.
3
Synthesis of Polymer-3. Monomer-1 (0.17 g, 0.26 mmol) and
2,5-dioctyloxy-1,4-benzenediboronic acid (0.11 g, 0.26 mmol)
were dissolved in 10 mL of dry DMF under N2. To the solution
were added K2CO3(aq) (2.0 M, 2 mL; N2 bubbled before use)
and Pd(PPh3)4 (0.015 g, 0.013 mmol). After the mixture was
stirred for 72 h at 80 °C, the mixture was poured in water. The
precipitate was washed with water, methanol, and acetone.
Polymer-3 was collected by filtration, dried under vacuum,
1
and obtained as a black powder (0.21 g, 98%). H NMR (400
MHz, CDCl3): δ 7.57 (8H), 6.77-6.97 (5H), 3.75-8.18 (20H),
1.70 (4H), 1.26-1.35 (20H), 0.87 (6H). 13C NMR (100 MHz,
DMSO-d6): δ 154.8, 150.4, 149.9, 139.5, 132.2, 130.0, 129.6,
128.4, 128.0, 125.5, 120.8, 115.8, 114.8, 113.2, 112.9, 71.0, 70.1,
69.6, 68.9, 31.8, 29.3, 26.1, 22.7, 14.1. Calcd for (C50H63N3O7)n:
C, 73.41; H, 7.76; N, 5.14. Found: C, 73.15; H, 7.31; N, 5.29.
Polymer-4 was synthesized analogously.
Synthesis of Monomer-1. N,N0-Bis[chloro(p-bromophe-
nyl)methylene]hydrazine (0.64 g, 1.5 mmol) and 40-aminoben-
zo-15-crown-5-ether (0.50 g, 1.8 mmol) were dissolved in 12 mL
of N,N-dimethyaniline under N2. After the solution was stirred
at 135 °C for 24 h, the reaction solution was cooled to room
temperature and poured in hexane (200 mL). The resulting
precipitate was washed with water dried under vacuum to give
monomer-1 a light yellow powder (0.78 g, 82%). 1H NMR (400
MHz, CDCl3): δ 7.45 (d, J = 8.4 Hz, 4H), 7.33 (d, J = 8.4 Hz,
4H), 6.86 (d, J = 8.4 Hz, 1H), 6.70 (dd, J = 2.0 and 8.6 Hz, 1H),
6.59 (d, J = 2.4 Hz, 1H), 4.17 (m, 2H), 3.94 (m, 4H), 3.84 (m,
2H), 3.75-3.81 (m, 8H). 13C NMR (100 MHz, CDCl3): δ 153.7,
149.2, 148.6, 131.6, 130.2, 126.8, 126.2, 123.4, 120.5, 113.3,
113.1, 70.5, 69.5, 68.5, 68.4, 68.2, 68.1. Calcd for C28H19Br2-
N3O5: C, 52.11; H, 4.22; N, 6.51. Found: C, 52.58; H, 4.14; N,
6.57. Mp = 259-261 °C.
Data of Polymer-4. 1H NMR (400 MHz, CD2Cl2): δ 7.57
(8H), 7.23 (2H), 7.00 (4H), 3.93 (3H), 3.87 (4H), 1.68 (4H), 1.28
(20H), 0.89 (6H). Calcd for (C43H51N3O3)n: C, 78.50; H, 7.81; N,
6.39. Found: C, 78.30; H, 7.68; N, 6.74.
Synthesis of Polymer-5. Monomer-1 (0.20 g, 0.31 mmol), 1,4-
diethynylbenzene (0.039 g, 0.31 mmol), and CuI (2.9 mg, 0.0016
mmol) were dissolved in 10 mL of dry toluene under N2. To the
solution were added Pd(PPh3)4 (0.018 g, 0.016 mmol) and
triethylamine (1 mL). After the mixture was stirred for 72 h at
90 °C, the precipitate was collected by filtration, washed with
methanol and chloroform, and dried under vacuum to give
polymer-5 as a light brown powder (0.14 g, 78%). Calcd for
(C38H31N3O5)n: C, 73.86; H, 5.03; N, 6.43. Found: C, 73.69; H,
4.96; N, 5.93.
Monomer-2 was synthesized by the reaction of N,N0-bis-
[chloro(p-bromophenyl)methylene]hydrazine with 4-aminoani-
sole in a similar manner.
Data of Monomer-2. 1H NMR (400 MHz, DMSO-d6): δ 7.60
(d, J = 6.8 Hz, 4H), 7.37 (d, J = 8.8 Hz, 2H), 7.34 (d, J = 6.8 Hz,
4H), 7.02 (d, J = 8.8 Hz, 2H), 3.78 (s, 3H). 13C NMR (100 MHz,
CDCl3): δ 159.8, 153.8, 131.6, 130.3, 129.4, 126.2, 123.4, 115.0,
55.4. Calcd for C21H15Br2N3O: C, 51.99; H, 3.12; N, 8.66.
Found: C, 52.04; H, 3.29; N, 8.78. Mp = 265-268 °C.
Polymer-6 was synthesized analogously. Data of polymer-6:
Calcd for (C31H19N3O)n: C, 78.14; H, 4.09; N, 8.82. Found: C,
78.36; H, 4.10; N, 8.51.
Preparation of Polymer-1(Naþ). After a DMSO solution
(15 mL) of polymer-1 (0.048 g, 0.10 mmol) and NaClO4 (0.12 g,
1.0 mol) was stirred at 120 °C for 12 h, the solvent was removed
under vacuum. The resulting solid was washed with water
Synthesis of Model-1. A mixture of N,N0-diformylhydrazine
(0.22 g, 2.4 mmol), 40-aminobenzo-15-crown-5-ether (0.69 g,

9354 Macromolecules, Vol. 43, No. 22, 2010
Yamaguchi and Mitsuno
(100 mL) and dried under vacuum to give polymer-1(Naþ)
(0.046 g).
Electric Conductivity Measurements. The n-doping was car-
ried out by using sodium naphthalenide according to the usual
manner.3
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Supporting Information Available: PL and TGA data. This
material is available free of charge via the Internet at http://
pubs.acs.org.
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