Synthesis, characterization, and optical and electrochemical properties of new 2,1,3-benzoselenadiazole-based CT-type copolymers

Article abstract of DOI:10.1021/ma051102i

New alternating donor-acceptor charge-transfer (CT)-type copolymers consisting of didodecyloxy-p-phenylene (Ph), N-(4-dodecyloxyphenyl)carbazole (Cz), or N-hexyldiphenylamine (Da) unit (π-electron donor) and 2,1,3-benzoselenadiazole (BSe) unit (π-electron

Full text of DOI:10.1021/ma051102i

7378
Macromolecules 2005, 38, 7378-7385
Synthesis, Characterization, and Optical and Electrochemical Properties
of New 2,1,3-Benzoselenadiazole-Based CT-Type Copolymers
Takuma Yasuda,† Tatsuya Imase,‡ and Takakazu Yamamoto*,†
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku,
Yokohama 226-8503, Japan, and Department of Electronic Chemistry, Interdisciplinary Graduate
School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku,
Yokohama 226-8503, Japan
Received May 29, 2005; Revised Manuscript Received June 28, 2005
ABSTRACT: New alternating donor-acceptor charge-transfer (CT)-type copolymers consisting of di-
dodecyloxy-p-phenylene (Ph), N-(4-dodecyloxyphenyl)carbazole (Cz), or N-hexyldiphenylamine (Da) unit
(π-electron donor) and 2,1,3-benzoselenadiazole (BSe) unit (π-electron acceptor) were prepared by
palladium-catalyzed Suzuki coupling reaction in 85-96% yields. The copolymers with the Ph and Cz
units were soluble in common organic solvents and gave number-average molecular weights of 8300 and
6600, respectively, in GPC analysis; the copolymer with the Da unit was partly soluble in the solvents.
The UV-vis absorption peak of the polymers appeared in the range of 420-530 nm in solutions and
films, and the optical transition is considered to be accompanied by CT from the donor unit to the BSe
unit. Quantum-chemical calculations of a trimeric model compound (Ph-BSe-Ph: 10) supported the
notion that the optical activation of the copolymer involved the CT process. Cyclic voltammetry revealed
that the copolymers were susceptible to both electrochemical oxidation and reduction, and they had a
LUMO level ranging from -3.08 to -2.91 eV and a HOMO level ranging from -5.56 to -5.12 eV.
Comparison of the electronic effect of the BSe unit with that of a 2,1,3-benzothiadiazole unit is discussed.
Introduction
zole (BSe) unit. Cao and co-workers reported synthesis
of several π-conjugated polymers containing the BSe
unit or a 2,1,3-naphthoselenadiazole unit; however,
examples of π-conjugated polymers containing such
units are still not many.14 Because differences in chemi-
cal properties between selenium in the BSe unit and
sulfur in the BTd unit may render interesting func-
tionalities to the aimed π-conjugated polymer, expansion
of the chemistry of π-conjugated polymers containing
the BSe unit is considered to be needed. The replace-
ment of sulfur of tetrathiafulvalene (TTF) with selenium
is one of the promising modifications for extending the
metallic state of a charge-transfer (CT) salt of TTF with
tetracyano-p-quinodimethane (TCNQ).15
In this paper, we describe synthesis, characterization,
and optical and electrochemical properties of new pro-
cessable BSe-containing donor-acceptor π-conjugated
polymers. As illustrated in Chart 2, dialkoxy-p-phe-
nylene (Ph), carbazole (Cz), and diphenylamine (Da)
units were chosen as the partner donor component. Such
hybridization of the donor (D in Chart 2) and acceptor
moieties will facilitate manipulation of the electronic
structure of the polymer,16 and various CT-type π-con-
jugated polymers have been prepared.7,11,17
For the copolymer with the Ph unit, it apparently
forms a π-conjugated system along the polymer main
chain. In cases of the copolymers with the Cz or Da unit,
they do not have such a π-conjugated system formally
due to the presence of consecutive C-N-C single bonds.
However, the copolymers seem to be able to form an
expanded electron system through the Cz and Da units
because homopolymers constituted of the Da unit,
(Da)n, also seem to form such an expanded electron
system as judged from their UV-vis peak position (λmax
) about 380 nm)18 which is comparable to that of poly-
(p-phenylene) (λmax ) about 380 nm). Optical data of
the copolymers with the Cz or Da unit also support
formation of such an expanded electron system, as
described below.
There is currently much attention focused on π-con-
jugated polymers due to their potential usability for
polymer optoelectronic devices such as light-emitting
diodes (OLEDs),1 field-effect transistors (FETs),2 and
photovoltaic devices.3 Electrically conducting polypyr-
role and poly(ethylenedioxythiophene) are industrially
used to prepare, for example, electric capacitors and
PET-based conducting films. Among π-conjugated poly-
mers, those containing benzene-fused heteroaromatic
rings with nitrogen atom(s), so-called poly(benzazole)s,
are a class of materials that has shown interesting
electrical and optical properties. Poly(2,1,3-benzothia-
diazole-4,7-diyl),4 poly(2-alkyl-benzimidazole-4,7-diyl),4,5
and poly(2-alkyl-1,2,3-benzotriazole-4,7-diyl)6 were pre-
viously reported, and they showed n-type electronic
properties.
2,1,3-Benzothiadiazole (Chart 1) is a well-known
heteroaromatic compound with a high electron-accept-
ing feature because of containing two electron-with-
drawing imine (CdN) nitrogens. Various π-conjugated
copolymers of 2,1,3-benzothiadiazole with thiophene,7
pyrrole,8 carbazole,9 fluorene,10 and dialkoxy-p-phenyl-
eneethynylene units11 have been developed to date. It
was reported that introduction of the 2,1,3-benzothia-
diazole (BTd) unit into the π-conjugated polyfluorene
backbone improved the electron-transporting ability and
the electroluminescence (EL) efficiency of the polymer.9a
Applications of such donor-acceptor copolymers to
OLEDs and to bulk heterojunction photovoltaic devices
have recently been studied.12,13
We aim for replacement of sulfur atom in the BTd
unit with selenium and design new donor-acceptor CT-
type copolymers consisting of the 2,1,3-benzoselenadia-
† Chemical Resources Laboratory.
‡ Department of Electronic Chemistry.
* Corresponding author. E-mail: tyamamot@res.titech.ac.jp.
10.1021/ma051102i CCC: $30.25 © 2005 American Chemical Society
Published on Web 07/30/2005

Macromolecules, Vol. 38, No. 17, 2005
2,1,3-Benzoselenadiazole-Based CT-Type Copolymers 7379
Chart 1. Benzazoles Which Show Electron-Accepting Nature
Chart 2. New CT-Type Polymers Consisting of the
BSe Unit
As described in Scheme 2, preparation of the BSe-
containing copolymers, P(BSe-Ph), P(BSe-Cz), and P-
(BSe-Da), was accomplished via polycondensation be-
tween 1 and the corresponding diboronic esters under
Suzuki coupling conditions in the presence of Pd(PPh3)4,
K2CO3, and Aliquat336.20 A related trimeric model
compound, 10, and a BTd-containing polymer, P(BTd-
Da), were also prepared.
The polymerization results are summarized in Table
1. Yields of the polymers were higher than 85%. P(BSe-
Ph) and P(BSe-Cz) were readily soluble in organic
solvents such as CHCl3, THF, toluene, and 1,2-dichlo-
robenzene, whereas P(BSe-Da) and P(BTd-Da) were
only partially (ca. 50-70%) soluble in these solvents.
The number-average molecular weights (Mn’s) of the
polymers estimated from GPC ranged from 6400 to 8300
vs polystyrene standards, with the polydispersity index
(Mw/Mn) of 1.2-1.6. The Mn values corresponded to the
degree of polymerization (n in Scheme 2) of 11-19. For
P(BSe-Da) and P(BTd-Da), the Mn values were ob-
tained only for the CHCl3-soluble part, and the insoluble
part was considered to have a higher Mn.
Chart 3. Charge Transfer Which Occurs during the
Photoexcitation of 10
Results and Discussion
Thermogravimetric analysis (TGA) revealed that the
polymers were thermally stable up to 340 °C under N2,
and their 5% weight-loss temperatures (Td’s) ranged
from 360 to 442 °C (cf. Table 1).
Synthesis. Synthetic routes of the monomers are
outlined in Scheme 1. The X-ray crystal structure of 1
reveals a planar structure of the BSe ring in 1 with a
Se-N bond length of ca. 1.79 Å and a NdC bond length
of ca. 1.33 Å as shown in the Supporting Information
(Figure S1); these observed bond lengths are consistent
with the ortho-quinoid structure of 1.19
NMR and IR. Figure 1 depicts the 1H NMR spectra
of the polymers in CDCl3. The NMR spectrum of P(BSe-
Ph) (part a) gives two aromatic signals at about δ 7.7
and 7.4 in a 1:1 peak area ratio; they are assigned to
Scheme 1. Synthesis of the Monomersa
a Reagents and conditions: (i) SeO2, EtOH/H2O, reflux; (ii) Cu, K2CO3, DMSO, 180 °C; (iii) NBS, DMF, -10 °C to r.t.; (iv) (1)
n-BuLi, THF, -78 °C; (2) 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, -78 °C to r.t.; (v) NBS, THF, -78 °C to r.t.; (vi)
n-C6H13Br, tert-BuOK, THF, 60 °C. C12H25 and C6H13 represent dodecyl and hexyl groups, respectively.

7380 Yasuda et al.
Macromolecules, Vol. 38, No. 17, 2005
Table 1. Preparation of Donor-Acceptor Copolymers
a
a
b
polymer
yield (%)
color
Mn
Mw/Mn
Pn
Tdc (°C)
Tgd (°C)
P(BSe-Ph)
P(BSe-Cz)
P(BSe-Da)
P(BTd-Da)
85
96
95
96
bright-yellow
red
red-purple
red
8300
6600
6400e
7500e
1.6
1.2
1.4
1.4
13
11
15
19
384
360
374
442
92
141
164
144
a Estimated from GPC (eluent ) CHCl3, polystyrene standards). b Degree of polymerization based on the repeating unit. c 5% weight-
loss temperature measured by TGA under N2. d Glass-transition temperature measured by DSC under He. e For the CHCl3-soluble part.
Scheme 2. Synthesis of the Polymers and the Model
Compounda
the latter peak is overlapped with the CDCl3 impurity
peak.
IR spectra of the polymers show peaks originated from
the monomeric units. However, the ν(C-Br) peak at
about 920 cm-1 and the ν(O-B-O) peak at about 670
cm-1 of the monomers21 become unobservable (cf. Figure
S2).
UV-vis Absorption and Photoluminescence (PL).
The UV-vis and PL spectra of the polymers are
depicted in Figure 2. The spectroscopic data of the
polymers and the model compound are summarized in
Table 2. In solutions, the polymers gave two distinct
absorption peaks (λmax): one near 320 nm and another
in a range of 420-500 nm. The former peak is assigned
to a π-π* transition mainly occurred in the monomeric
units, whereas the lower-energy peak is mainly associ-
ated with electronic transition occurred in the main
chain. The appearance of the latter UV-vis peak of P-
(BSe-Cz) and P(BSe-Da) at the long wavelengths
supports the notion that these polymers have the
expanded conjugation system through the C-N-C
bonds in the Cz and Da units. An n-π* transition in
P(BSe-Cz) and P(BSe-Da) is considered to appear
around 300 nm; however, it seems to be hidden under
the strong π-π* transition band.22a
The lower energy UV-vis peak of the polymers is
shifted by 5-30 nm to a longer wavelength when
measured with cast films, presumably due to increase
in coplanarity of the polymer and/or occurrence of
intermolecular electronic interactions between the poly-
mer molecules in the solid state.
a Reagents and conditions: (i) Pd(PPh3)4, K2CO3, Aliquat336,
toluene/H2O, 85 °C. (ii) Pd(PPh3)4, K2CO3, THF/H2O, 60 °C.
The polymers show a yellow to deep-red PL emission
with the peak (λem) in a range of 554-685 nm in THF
(cf. Figure 2B) when irradiated with light at the lower
energy absorption peak. Photoexcitation of the polymers
with a shorter wavelength light at 300-335 nm gives
essentially the same PL spectra, revealing that the
photoenergy captured by the monomeric unit is trans-
ferred to the main chain.22b
Charge-Transfer (CT) Electronic State of the
Polymer. The alternating donor-acceptor structure of
the polymers seems to bring about a CT electronic
character both in the ground state and in the excited
state. The PL spectra of P(BSe-Cz) in various solvents
(toluene, THF, CH2Cl2, and NMP) are exhibited in
Figure 3A. When the polarity of the solvent increases
from less polar toluene to highly polar NMP, the λem
position of P(BSe-Cz) is red-shifted by 44 nm, showing
a positive solvatochromism.23 The PL intensity of the
solution gradually decreased with increase in the polar-
ity of the solvent and the Stokes shift. The degree of
the shift in PL is much larger than that (ca. 5 nm)
observed in the UV-vis spectrum, implying that the
excited state is highly polarized and stabilized by
solvation with the polar solvent after the photoexcita-
tion.23,24 Similar bathochromic shifts in PL were also
observed in P(BSe-Ph) and P(BSe-Da) as depicted in
Figure 3B. As demonstrated in Figure 3B, the PL peak
Figure 1. 1H NMR spectra of (a) P(BSe-Ph), (b) P(BSe-Cz),
and (c) P(BSe-Da) in CDCl3. The asterisk denotes the peak
due to H2O.
aromatic protons in the BSe unit and the Ph unit,
respectively. Peaks of the alkoxy side chains are ob-
served in the range of δ 3.93-0.82. In the 1H NMR
spectrum of P(BSe-Cz) (part b), there are six broad
aromatic peaks attributed to protons of the BSe
and the Cz units. For P(BSe-Da) (part c), a singlet
peak at δ 7.6 is assigned to protons of the BSe unit,
and the Da unit affords two doublets at δ 7.9 and 7.2;

Macromolecules, Vol. 38, No. 17, 2005
2,1,3-Benzoselenadiazole-Based CT-Type Copolymers 7381
Figure 2. (A) UV-vis and (B) PL spectra of (a) P(BSe-Ph) (- - -), (b) P(BSe-Cz) (s), and (c) P(BSe-Da) (‚ ‚ ‚) in THF at room
temperature. The PL spectra were recorded with excitation at the lower energy λmax wavelength.
Table 2. Optical Data of the Polymers and the Model Compounda
THF solution
filmc
polymer
10
P(BSe-Ph)
P(BSe-Cz)
P(BSe-Da)
P(BTd-Da)
λmax (nm)
λem (nm)
Stokes shift (eV)
Φb (%)
λmax (nm)
λem (nm)
301, 334, 403
310, 334, 424
303, 475
334, 500
321, 482
571
554
620
685
640
0.91
0.69
0.61
0.67
0.64
9
11
17
14
40
305, 343, 410
309, 342, 429
306, 486
343, 527
327, 501
557
538
633
666
635
a Measured at room temperature. b PL quantum yield calculated by comparing with the standard of quinine sulfate (ca. 10-5 M solution
in 0.5 M H2SO4 having a quantum yield of 54.6%). c Cast from a CHCl3 solution on a quartz plate.
Figure 3. (A) Normalized PL spectra of P(BSe-Cz) in solvents. (B) Plots of the PL peak (λem) energy of the three kinds of polymers
against the ET(30) value of the solvent.
Figure 4. Representation of HOMO and LUMO of 10 based on the B3LYP/6-31G* calculation.
shifts to a longer wavelength with increase in the ET-
(30) value,23a which is a measure of polarity of solvents.
To obtain further information about the CT electronic
structure of the polymers, density-functional theory
(DFT)25 calculations for the model compound 10 were
performed at the B3LYP/6-31G* level. Figure 4 repro-
duces the calculated molecular orbitals of 10. Although
the HOMO is delocalized over the π-conjugation sys-
tems, the LUMO is highly localized on the BSe unit.
This indicates that the HOMO-LUMO UV-vis transi-
tion is accompanied by CT from the dimethoxyphenyl
units to the central BSe unit (cf. Chart 3). The calcu-
lated HOMO-LUMO energy gap of 10 (2.85 eV) is in
good agreement with the optical energy gap (2.53 eV)
of 10 determined by the onset position of the UV-vis
peak.
Because the photoexcitation of the BSe-D (donor)
copolymer is also considered to be accompanied by

7382 Yasuda et al.
Macromolecules, Vol. 38, No. 17, 2005
easier process because of a higher electron-accepting
ability of the BSe unit than that of the BTd unit.
Electrochemical Response. The electrochemical
redox behavior of the polymers was investigated by
cyclic voltammetry (CV). As shown in Figure 5, all the
polymers exhibit both p-doping (oxidation) and n-doping
(reduction) peaks, and the CV data are listed in Table
3. The reduction peak appeared at -2.11 V vs Ag+/Ag
for P(BSe-Ph), -1.88 V for P(BSe-Cz), and -1.81 V
for P(BSe-Da). The n-doping in the polymer is consid-
ered to occur dominantly at the BSe moiety. The film
was stable in repeated scans, and the same CV chart
was obtained after 10 cycles when scanned in the
negative potential region. The n-doping of P(BSe-Da)
takes place at a negatively lower potential by about 0.1
V than that (-1.91 V vs Ag+/Ag) of P(BTd-Da). This
suggests that the BSe unit has a stronger electron-
accepting ability than the BTd unit, as discussed above.
In an oxidative potential region, a p-doping peak was
observed at 1.12 V vs Ag+/Ag for P(BSe-Ph), 0.89 V
for P(BSe-Cz), and 0.53 V for P(BSe-Da). The p-doping
is considered to occur mainly at the donor unit, and the
order of the p-doping potential is considered to reflect
electron-donating ability (or IP) of the Ph, Cz, and Da
units.
Figure 5. Cyclic voltammograms of films of (a) P(BSe-Ph),
(b) P(BSe-Cz), and (c) P(BSe-Da) on a Pt plate in an
acetonitrile solution of [(C2H5)4N]BF4 (0.10 M) under N2. Sweep
rate is 30 mV s-1
.
For p-doping of P(BSe-Ph), it was almost irrevers-
ible, and only a weak cathodic (or p-dedoping) peak
appeared at around 0.8 V vs Ag+/Ag (cf. Figure 5a).
π-Conjugated polymers with the dialkoxy-p-phenylene
unit often give such an irreversible p-doping peak,11b,24
which is considered to be due to a strong interaction of
the anion dopant (BF4- in this case) with the OR group-
(s). P(BSe-Cz) and P(BSe-Da) clearly give the p-
dedoping peak at 0.83 and 0.44 V vs Ag+/Ag, respec-
tively. The electrochemical reduction and oxidation are
accompanied by color changes (electrochromism) of the
polymer film, as shown in Figure 5.
The LUMO and the HOMO energy levels (ELUMO and
EHOMO) of the copolymers can be deduced from the onset
potentials of n- and p-doping waves, respectively, with
the assumption that the energy level of ferrocene (Fc)
is 4.8 eV below vacuum level.28 The ELUMO and the
EHOMO values of the polymers are included in Table 3.
The ELUMO ranges from -2.91 to -3.08 eV and is much
lower than that (-2.4 eV) of 2-(4-biphenyl)-5-(4-tert-
butylphenyl)-1,3,4-oxadiazole (PBD),29 one of the most
widely used electron-injecting/transporting materials in
OLEDs, and is comparable to that of cyano-substituted
poly(p-phenylenevinylene) (CN-PPV; ca. -3.0 eV).1b
These low-lying ELUMO values of the polymers are
considered to originate from the strong electron-accept-
ing property of the BSe unit.
electron transfer from the donor unit to the BSe unit,
the increase in the electron-donating ability of the donor
unit is expected to make the photoexcitation of the
copolymer easier and give the UV-vis peak at a longer
wavelength:
The order of the UV-vis absorption peak, λmax(P(BSe-
Da)) ) 500 nm > λmax(P(BSe-Cz)) ) 475 nm > λmax(P-
(BSe-Ph)) ) 424 nm, agrees with the order of the
ionization potential (IP) of the donor unit, IP(dipheny-
lamine)26 ) 7.36 eV < IP(carbazole)26 ) 7.57 eV < IP-
(dialkoxybenzene)27 ) ca. 8.6 eV. These results clearly
indicate that the photoexcited polymer molecule has the
charge-transferred polar structure. The ground state of
the polymer is also considered to have a partly charge-
transferred and polar structure due to the difference in
electronegativity between the BSe unit and the donor
unit. However, the degree of the CT in the ground state
is considered not to be so large as in the photoexcited
state because the UV-vis peak does not show such a
large solvatochromism as that observed with PL. The
appearance of the λmax of P(BSe-Da) at a longer
wavelength than that of P(BTd-Da) (cf. Table 2)
indicates that the photoexcitation in P(BSe-Da) is a
Table 3. Electrochemical Data and Energy Levels of the Copolymers
redox potentiala (V vs Ag+/Ag)
polymer
n-doping
n-dedoping
p-doping
p-dedoping
ELUMOb (eV)
EHOMOc (eV)
Egele d (eV)
Egopt e (eV)
P(BSe-Ph)
P(BSe-Cz)
P(BSe-Da)
P(BTd-Da)
-2.11 (-1.80)
-1.88 (-1.67)
-1.81 (-1.63)
-1.91 (-1.72)
-1.77
-1.68
-1.67
-1.83
1.12 (0.85)
0.89 (0.52)
0.53 (0.41)
0.57 (0.44)
0.83
0.83
0.44
0.49
-2.91
-3.04
-3.08
-2.99
-5.56
-5.23
-5.12
-5.15
2.65
2.19
2.04
2.16
2.41
2.05
1.95
2.04
a Measured by cyclic voltammetry in an acetonitrile solution of [(C2H5)4N]BF4 (0.10 M). The values in parentheses are onset potentials
of reduction and oxidation waves. b Calculated from the onset reduction potentials (Eonset(red) vs Ag+/Ag) by assuming that the absolute
energy level of Fc+/Fc is 4.8 eV below vacuum level: ELUMO ) -(Eonset(red) - 0.09) - 4.8 V. The value of 0.09 V is added to adjust the E
value obtained vs Ag+/Ag to Fc+/Fc. The value of 0.09 V was obtained experimentally for the used electrochemical measuring system, and
similar adjusting values have been reported.28b-d c Calculated from the onset oxidation potentials (Eonset(ox) vs Ag+/Ag) by assuming that
the absolute energy level of Fc+/Fc is 4.8 eV below vacuum level: EHOMO ) -(Eonset(ox) - 0.09) - 4.8 eV. d Calculated by the equation:
Eg ) ELUMO - EHOMO.
e Estimated from the onset position of the UV-vis absorption spectrum of the thin film.
ele

Macromolecules, Vol. 38, No. 17, 2005
2,1,3-Benzoselenadiazole-Based CT-Type Copolymers 7383
ele
(4.68 g, 8.0 mmol) in dry THF (70 mL) at -78 °C was added
dropwise 11.4 mL (18.0 mmol) of butyllithium (1.58 M in
hexane), and the mixture was allowed to react for 2 h at -78
°C under N2. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaboro-
lane (5.95 g, 32.0 mmol) was added to the solution, and the
mixture was stirred overnight at room temperature. The
resulting mixture was poured into water and was extracted
with ether. The organic layer was washed with water and dried
over anhydrous sodium sulfate. After filtration and evapora-
tion, the residue was purified by column chromatography
(silica, hexane/ethyl acetate ) 9:1, v/v) and dried under
vacuum to provide 4 as a pale-yellow solid (yield ) 2.27 g,
42%). 1H NMR (400 MHz, CDCl3): δ 8.69 (s, 2H), 7.82 (d, J )
8.0 Hz, 2H), 7.40 (d, J ) 8.8 Hz, 2H), 7.28 (d, J ) 8.0 Hz, 2H),
7.09 (d, J ) 8.8 Hz, 2H), 4.05 (t, J ) 6.4 Hz, 2H), 1.85 (m,
2H), 1.55-1.27 (m, 18H), 1.39 (s, 24H), 0.89 (t, J ) 6.8 Hz,
3H). Anal. Calcd for C42H59B2NO5: C, 74.23; H, 8.75; N, 2.06.
Found: C, 74.08; H, 8.46; N, 2.11.
N-Hexyl-4,4′-dibromodiphenylamine (6). A mixture of
5 (9.81 g, 30.0 mmol), potassium tert-butoxide (4.04 g, 36.0
mmol), and 150 mL of dry THF was stirred for 0.5 h at room
temperature under N2. 1-Bromohexane (5.94 g, 36.0 mL) was
added to the solution, and the mixture was stirred for 24 h at
60 °C. After cooling to room temperature, the reaction mixture
was poured into water and then extracted with chloroform.
The combined organic layers were washed with water and
dried over anhydrous magnesium sulfate. After filtration, the
solvent was evaporated. The crude product was purified by
column chromatography (silica, hexane/chloroform ) 2:1, v/v)
and dried under vacuum to give 6 as a colorless oil (11.38 g,
92%). 1H NMR (400 MHz, CDCl3): δ 7.33 (d, J ) 9.2 Hz, 4H),
6.83 (d, J ) 9.2 Hz, 4H), 3.60 (t, J ) 7.8 Hz, 2H), 1.60 (m,
2H), 1.32-1.27 (m, 6H), 0.87 (t, J ) 6.8 Hz, 3H). 13C NMR
(100 MHz, CDCl3): δ 146.64, 132.16, 122.48, 113.78, 52.47,
31.61, 27.28, 26.73, 22.67, 14.06. Anal. Calcd for C18H21Br2N:
C, 52.58; H, 5.15; Br, 38.86; N, 3.41. Found: C, 52.71; H, 5.08;
Br, 39.14; N, 3.43.
The electrochemical band gap, Eg
() ELUMO -
EHOMO), is somewhat larger than the optically deter-
mined one (Egopt), presumably due to an interface barrier
for charge injection.30 These electrochemical data sug-
gest that the electron-deficient BSe unit and the
electron-rich Ph, Cz, and Da units lead to an increase
in both electron and hole affinities, and the obtained
polymers are expected to improve charge-transporting
balance in electronic devices.
Conclusions
A series of donor-acceptor arranged polymers con-
sisting of the electron-accepting BSe unit were synthe-
sized via Suzuki coupling reaction. The UV-vis data
and the solvent-dependent PL of the polymers support
the presence of the CT electronic state, especially in the
excited state. The p-n alternating copolymers were
electrochemically active in both oxidation and reduction
regions, as revealed by cyclic voltammetry. The obtained
results are expected to contribute for designing elec-
tronic and optical devices by using such ambipolar
charge-transporting materials.
Experimental Section
Materials and Syntheses. 3,6-Dibromo-1,2-phenylenedi-
amine, carbazole, diphenylamine, 2-isopropoxy-4,4,5,5-tetram-
ethyl-1,3,2-dioxaborolane, 2,5-dimethoxyphenylboronic acid,
and Aliquat336 were purchased and used without further
purification. 1-Dodecyloxy-4-iodobenzene,31 4,7-dibromo-2,1,3-
benzoselenadiazole (1),32 4,4′-dibromodiphenylamine (5),18 1,4-
bis(5,5-dimethyl-1,3,2-dioxaborinane-2-yl)-2,5-didodecyloxy-
benzene (8),24a 4,7-dibromo-2,1,3-benzothiadiazole (9),4 and
33
Pd(PPh3)4 were prepared according to the literature.
9-(4-Dodecyloxyphenyl)carbazole (2). A mixture of car-
bazole (6.69 g, 40.0 mmol), 1-dodecyloxy-4-iodobenzene (17.09
g, 44.0 mmol), activated copper34 (4.07 g, 64.0 mmol), potas-
sium carbonate (11.06 g, 80.0 mmol), and dry DMSO (20 mL)
was stirred for 42 h at 180 °C under N2. The reaction mixture
was cooled, diluted with acetone, and filtered. The filtrate was
added into water to form a white precipitate, which was
collected by filtration, washed with water and methanol, and
recrystallized from acetone/methanol to give 2 as a white solid
4,4′-Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)-
N-hexyldiphenylamine (7). To a solution of 6 (10.28 g, 25.0
mmol) in dry THF (180 mL) at -78 °C was added dropwise
38.5 mL (60.0 mmol) of butyllithium (1.56 M in hexane) under
N2. After the mixture was stirred for 2 h at -78 °C, 2-isopro-
poxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (18.61 g, 100 mmol)
was added to the solution, and the mixture was warmed to
room temperature and stirred overnight. The resulting mixture
was poured into water, extracted with ether, and then dried
over anhydrous magnesium sulfate. After evaporation, the
crude product was recrystallized from hexane and dried under
vacuum to provide 7 as bluish-white crystals (yield ) 7.29 g,
58%). 1H NMR (400 MHz, CDCl3): δ 7.69 (d, J ) 8.8 Hz, 4H),
7.00 (d, J ) 8.8 Hz, 4H), 3.72 (t, J ) 7.6 Hz, 2H), 1.64 (m,
2H), 1.33 (s, 24H), 1.27 (m, 6H), 0.86 (t, J ) 6.8 Hz, 3H). FT-
IR (KBr, cm-1): 2979, 2930, 1610, 1594, 1397, 1357, 1320,
1274, 1145, 1093, 963, 859, 658. Anal. Calcd for C30H45B2-
NO4: C, 71.31; H, 8.98; N, 2.77. Found: C, 71.12; H, 8.60; N,
2.88.
P(BSe-Ph). 1 (1.02 g, 3.0 mmol) and 8 (2.01 g, 3.0 mmol)
were dissolved in 30 mL of dry toluene under N2. To the
solution were added K2CO3(aq) (2.0 M, 15 mL; N2 bubbled
before use), Pd(PPh3)4 (0.17 g, 0.15 mmol), and a phase transfer
catalyst, Aliquat336 (0.10 g, 0.24 mmol). After the mixture was
stirred for 72 h at 85 °C, it was added into methanol to obtain
a precipitate. The crude product was separated by filtration
and washed with water, methanol, and acetone. The obtained
polymer was dissolved in chloroform and reprecipitated in
methanol. P(BSe-Ph) was collected by filtration, dried under
vacuum, and obtained as a bright-yellow powder (yield ) 1.60
g, 85%). 1H NMR (400 MHz, CDCl3): δ 7.70 (br, 2H), 7.37 (br,
2H), 3.93 (br, 4H), 1.49 (br, 4H), 1.16 (br, 36H), 0.82 (br, 6H).
FT-IR (KBr, cm-1): 2924, 2853, 1505, 1467, 1416, 1377, 1211,
1033, 846, 761. Anal. Calcd for Br-(C36H54N2O2Se)13-B(OH)2
(Mn ) 8260): C, 68.05; H, 8.59; N, 4.41; O, 5.42; Br, 0.97.
Found: C, 68.48; H, 8.34; N, 4.41; O, 5.37; Br, 0.77.
1
(yield ) 6.05 g, 35%). H NMR (400 MHz, CDCl3): δ 8.13 (d,
J ) 8.0 Hz, 2H), 7.43-7.24 (m, 8H), 7.09 (d, J ) 8.8 Hz, 2H),
4.05 (t, J ) 6.4 Hz, 2H), 1.85 (m, 2H), 1.53-1.27 (m, 18H),
0.89 (t, J ) 6.8 Hz, 3H). 13C NMR (100 MHz, CDCl3): δ 158.34,
141.28, 129.95, 128.43, 125.72, 122.99, 120.15, 119.51, 115.49,
109.64, 68.40, 31.98, 29.74, 29.71, 29.68, 29.66, 29.48, 29.42,
29.36, 26.15, 22.76, 14.21. Anal. Calcd for C30H37NO: C, 84.26;
H, 8.72; N, 3.28. Found: C, 83.53; H, 8.41; N, 3.23.
3,6-Dibromo-9-(4-dodecyloxyphenyl)carbazole (3). To
a solution of 2 (5.56 g, 13.0 mmol) in dry DMF (120 mL) was
slowly added NBS (4.63 g, 26.0 mmol) -10 °C, and the mixture
was stirred for 10 h at room temperature. The mixture was
poured into a large amount of water to form a precipitate. The
precipitate was separated by filtration, washed with water and
methanol, and purified by column chromatography (silica,
chloroform/hexane ) 1:1, v/v). After evaporation, the product
was recrystallized from acetone/methanol and dried under
vacuum to give 3 as a white solid (yield ) 7.07 g, 93%). 1H
NMR (400 MHz, CDCl3): δ 8.18 (d, J ) 2.0 Hz, 2H), 7.48 (dd,
J ) 8.8 and 2.0 Hz, 2H), 7.35 (d, J ) 8.8 Hz, 2H), 7.16 (d, J )
8.8 Hz, 2H), 7.08 (d, J ) 8.8 Hz, 2H), 4.04 (t, J ) 6.4 Hz, 2H),
1.85 (m, 2H), 1.55-1.27 (m, 18H), 0.89 (t, J ) 6.8 Hz, 3H). 13
C
NMR (100 MHz, CDCl3): δ 158.79, 140.26, 129.19, 128.91,
128.25, 123.58, 123.05, 115.69, 112.70, 111.41, 68.45, 31.97,
29.73, 29.71, 29.67, 29.66, 29.47, 29.42, 29.30, 26.13, 22.76,
14.21. Anal. Calcd for C30H35Br2NO: C, 61.55; H, 6.03; Br,
27.30; N, 2.39. Found: C, 61.50; H, 5.99; Br, 27.05; N, 2.39.
3,6-Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-2-yl)-9-
(4-dodecyloxyphenyl)carbazole (4). To a solution of 3
Other copolymers were prepared analogously. Spectroscopic
and analytical data of the polymers are shown below.

7384 Yasuda et al.
Macromolecules, Vol. 38, No. 17, 2005
P(BSe-Cz). Red powder (yield ) 96%). 1H NMR (400 MHz,
CDCl3): δ 8.70-6.98 (m, 12H), 4.07 (br, 2H), 1.87 (br, 2H),
1.29 (br, 18H), 0.88 (br, 3H). FT-IR (KBr, cm-1): 2923, 2852,
1602, 1513, 1471, 1362, 1285, 1243, 1181, 809. Anal. Calcd
for Br-(C36H37N3OSe)11-B(OH)2 (Mn ) 6798): C, 69.97; H,
6.06; N, 6.80; O, 3.06; Br, 1.18. Found: C, 70.55; H, 5.97; N,
6.27; O, 3.19; Br, 1.19.
Acknowledgment. We acknowledge to the Global
Scientific Information and Computing Center in our
institute for generous permission to use the SGI Origin
2000/128. This work was partly supported by a grant
for the 21st Century Center of Excellence (COE) pro-
gram.
P(BSe-Da). Red-purple powder (yield ) 95%). 1H NMR (400
MHz, CDCl3): δ 7.87 (d, 4H), 7.62 (s, 2H), 7.24 (d, 4H), 3.85
(br, 2H), 1.81 (br, 2H), 1.35 (br, 6H), 0.91 (br, 3H). FT-IR (KBr,
cm-1): 3132, 2924, 2852, 1597, 1509, 1468, 1362, 1251, 1188,
Supporting Information Available: X-ray crystal struc-
ture of 1, FT-IR spectra and TGA thermograms of the
polymers, and HOMO and LUMO representations for tri-
meric model compounds containing a Cz or Da unit. This
material is available free of charge via the Internet at http://
pubs.acs.org.
818, 767. Anal. Calcd for Br-(C24H23N3Se)15-B(OH)2 (Mn
)
6611): C, 65.40; H, 5.29; N, 9.53; Br, 1.21. Found: C, 65.79;
H, 5.27; N, 9.19; Br, 0.
P(BTd-Da). Red powder (yield ) 96%). 1H NMR (400 MHz,
CDCl3): δ 7.96 (d, 4H), 7.78 (s, 2H), 7.27 (d, 4H), 3.87 (br, 2H),
1.82 (br, 2H), 1.36 (br, 6H), 0.91 (br, 3H). FT-IR (KBr, cm-1):
2924, 2853, 1598, 1515, 1477, 1362, 1252, 1189, 1116, 888, 818.
Anal. Calcd for Br-(C24H23N3S)19-B(OH)2 (Mn ) 7450): C,
73.52; H, 5.94; N, 10.72; S, 8.18; Br, 1.07. Found: C, 73.94; H,
6.07; N, 10.70; S, 7.90; Br, 0.
References and Notes
(1) (a) Burroughes, J. H.; Bradley, D. D. C.; Brown, A. R.; Marks,
R. N.; Mackay, K.; Friend, R. H.; Burns, P. L.; Holmes, A. B.
Nature (London) 1990, 347, 539. (b) Greenham, N. C.;
Moratti, S. C.; Bradley, D. D. C.; Friend, R. H.; Holmes, A.
B. Nature (London) 1993, 365, 628. (c) Friend, R. H.; Gymer,
R. W.; Holmes, A. B.; Burroughes, J. H.; Marks, R. N.;
Taliani, C.; Bradley, D. D. C.; Dos Santos, D. A.; Bre´das, J.
L.; Lo¨gdlund, M.; Salaneck, W. R. Nature (London) 1999, 397,
121.
(2) (a) Garnier, F.; Hajlaoui, R.; Yassar, A.; Srivastava, P. Science
1994, 265, 1684. (b) Sirringhaus, H.; Tessler, N.; Friend, R.
H. Science 1998, 280, 1741. (c) Sirringhaus, H.; Brown, P.
J.; Friend, R. H.; Nielsen, M. M.; Bechgaard, K.; Langeveld-
Voss, B. M. W.; Spiering, A. J. H.; Janssen, R. A. J.; Meijer,
E. W.; Herwig, P.; de Leeuw, D. M. Nature (London) 1999,
401, 685.
(3) (a) Yu, G.; Gao, J.; Hummelen, J. C.; Wudl, F.; Heeger, A. J.
Science 1995, 270, 1789. (b) Granstro¨m, M.; Petritsch, K.;
Arias, A. C.; Lux, A.; Andersson, M. R.; Friend, R. H. Nature
(London) 1998, 395, 257. (c) Huynh, W. U.; Dittmer, J. J.;
Alivisatos, A. P. Science 2002, 295, 2425.
(4) Kanbara, T.; Yamamoto, T. Chem. Lett. 1993, 419.
(5) Yamamoto, T.; Sugiyama, K.; Kanbara, T.; Hayashi, H.; Etori,
H. Macromol. Chem. Phys. 1998, 199, 1807.
(6) Tanimoto, A.; Yamamoto, T. Adv. Synth. Catal. 2004, 246,
1818.
(7) (a) Karikomi, M.; Kitamura, C.; Tanaka, S.; Yamashita, Y.
J. Am. Chem. Soc. 1995, 117, 6791. (b) Jayakannan, M.; van
Hal, P. A.; Janssen, R. A. J. J. Polym. Sci., Part A: Polym.
Chem. 2002, 40, 251. (c) Jayakannan, M.; van Hal, P. A.;
Janssen, R. A. J. J. Polym. Sci., Part A: Polym. Chem. 2002,
40, 2360.
(8) (a) Dhanabalan, A.; van Dongen, J. L. V.; van Duren, J. K.
J.; Janssen, H. M.; van Hal, P. A.; Janssen, R. A. J.
Macromolecules 2001, 34, 2495. (b) Dhanabalan, A.; van
Duren, J. K. J.; van Hal, P. A.; van Dongen, J. L. J.; Janssen,
R. A. J. Adv. Funct. Mater. 2001, 11, 255.
(9) (a) Huang, J.; Niu, Y.; Yang, W.; Mo, Y.; Yuan, M.; Cao, Y.
Macromolecules 2002, 35, 6080. (b) Huang, J.; Xu, Y.; Hou,
Q.; Yang, W.; Yuan, M. Cao, Y. Macromol. Rapid Commun.
2002, 23, 709.
(10) (a) Herguth, P.; Jiang, X.; Liu, M. S.; Jen, A. K.-Y. Macro-
molecules 2002, 35, 6094. (b) Huang, F.; Hou, L.; Wu, H.;
Wang, X.; Shen, H.; Cao, W.; Yang, W.; Cao, Y. J. Am. Chem.
Soc. 2004, 126, 9845. (c) Liu, B.; Bazan, G. C. J. Am. Chem.
Soc. 2004, 126, 1942.
(11) (a) Bangcuyo, C. G.; Evans, U.; Myrick, M. L.; Bunz, U. H.
F. Macromolecules 2001, 34, 7592. (b) Morikita, T.; Yamagu-
chi, I.; Yamamoto, T. Adv. Mater. 2001, 13, 1862. (c) Yama-
moto, T.; Fang, Q.; Morikita, T. Macromolecules 2003, 36,
4262.
(12) (a) He, Y.; Gong, S.; Hattori, R.; Kanicki, J. Appl. Phys. Lett.
1999, 74, 2265. (b) He, Y.; Kanicki, J. Appl. Phys. Lett. 2000,
76, 661. (c) Morteani, A. C.; Dhoot, A. S.; Kim, J.-S.; Silva,
C.; Greenham, N. C.; Murphy, C.; Moons, E.; Cina´, S.;
Burroughes, J. H.; Friend, R. H. Adv. Mater. 2003, 15, 1708.
(13) (a) Arias, A. C.; MacKenzie, J. D.; Stevenson, R.; Halls, J. J.
M.; Inbasekaran, M.; Woo, E. P.; Richards, D.; Friend, R. H.
Macromolecules 2001, 34, 6005. (b) Brabec, C. J.; Winder,
C.; Sariciftci, N. S.; Hummelen, J. C.; Dhanabalan, A.; van
Hal, P. A.; Janssen, R. A. J. Adv. Funct. Mater. 2002, 12,
709.
4,7-Bis(2,5-dimethoxyphenyl)-2,1,3-benzoselenadiaz-
ole (10). Reaction of 1 (0.41 g, 1.2 mmol), 2,5-dimethoxyphe-
nylboronic acid (0.55 g, 3.0 mmol), and Pd(PPh3)4 (0.06 g, 0.05
mmol) was carried out under similar conditions; THF was used
as a solvent, instead of toluene. 10 was obtained as a yellow
powder after purification by column chromatography (silica,
chloroform as an eluent) and recrystallization form acetone/
1
methanol (yield ) 0.52 g, 95%). H NMR (400 MHz, CDCl3):
δ 7.54 (s, 2H), 7.09 (d, J ) 3.2 Hz, 2H), 7.01 (d, J ) 9.2 Hz,
2H), 6.96 (dd, J ) 9.2 and 3.2 Hz, 2H), 3.81 (s, 6H), 3.74 (s,
6H). 13C NMR (100 MHz, CDCl3): δ 159.59, 153.38, 151.34,
132.45, 129.67, 127.96, 117.44, 114.26, 112.75, 56.50, 55.80.
FT-IR (KBr, cm-1): 2996, 2951, 2832, 1582, 1498, 1464, 1422,
1298, 1267, 1217, 1180, 1093, 1047, 1023, 968, 852, 806, 766,
736. Anal. Calcd for C22H20N2O4Se: C, 58.03; H, 4.43; N, 6.15.
Found: C, 57.39; H, 4.41; N, 6.18.
Instruments and Methods. NMR and FT-IR spectra were
recorded on a JEOL EX-400 spectrometer and a JASCO FT/
IR-460 Plus spectrometer, respectively. Elemental analyses
were carried out with a LECO CHNS-932 analyzer and a
Yanaco YS-10 SX-Elements microanalyzer. GPC traces were
obtained with a Shimadzu LC-9A chromatograph equipped
with a UV detector and Shodex 80M columns (eluent ) CHCl3;
polystyrene standards). Thermogravimetric analysis (TGA)
and differential scanning calorimetry (DSC) were performed
on a Shimadzu TGA-50 and a DSC-50 analyzer, respectively.
The cast film was prepared from a dilute chloroform solution.
UV-vis absorption and PL spectra were measured with a
Shimadzu UV-3100 spectrometer and a Hitachi F-4010 spec-
trophotometer, respectively. Cyclic voltammetry of cast films
of the polymers on a Pt plate was performed in an acetonitrile
solution of [(C2H5)4N]BF4 (0.10 M) with a Pt counter electrode
and an Ag+/Ag reference electrode with a Toyo Technica
Solartron SI 1287 electrochemical interface. Single crystals of
1 were grown from a chloroform solution. X-ray crystal-
lographic analysis was made on a Rigaku Saturn CCD dif-
fractmeter with graphite monochromated Mo KR radiation.
Data were processed using the Rigaku CrystalClear software
package. The structure was solved by direct methods (SIR-
92),35 and structural parameters of non-hydrogen atoms were
refined anisotropically according to a full-matrix least-squares
technique.
The quantum-chemical calculations of the trimeric model
compound 10 were performed using the Gaussian 03 series of
programs36 on a SGI Origin2000/128 at the Global Scientific
Information and Computing Center of Tokyo Institute of
Technology. Ground-state geometries were optimized at the
Becke’s three-parameter hybrid functional using the Lee-
Yang-Parr correlation functional (B3LYP) level with the
6-31G* basis set. Vibrational analysis was carried at the same
levels of the theory to optimize the structure as equilibrium
structures.
(14) (a) Yang, R.; Tian, R.; Hou, Q.; Yang, W.; Cao, Y. Macromol-
ecules 2003, 36, 7453. (b) Yang, J.; Jiang, C.; Zhang, Y.; Yang,
R.; Yang, W.; Hou, Q.; Cao, Y. Macromolecules 2004, 37, 1211.

Macromolecules, Vol. 38, No. 17, 2005
2,1,3-Benzoselenadiazole-Based CT-Type Copolymers 7385
(c) Yang, R.; Tian, R.; Yan, J.; Zhang, Y.; Yang, J.; Hou, Q.;
Yang, W.; Zhang, C.; Cao, Y. Macromolecules 2005, 38, 244.
(15) Cowan, D.; Kini, A. The Chemistry of Organic Selenium and
Tellurium; Patai, S., Ed.; John Wiley: New York, 1987; Vol.
2.
(16) (a) Brocks, G.; Tol, A. J. Phys. Chem. 1996, 100, 1838. (b)
Jenekhe, S. A.; Lu, L.; Alam, M. M. Macromolecules 2001,
34, 7315.
(17) (a) Yamamoto, T.; Zhou, Z.-H.; Kanbara, T.; Shimura, M.;
Kizu, K.; Maruyama, T.; Nakamura, Y.; Fukuda, T.; Lee, B.-
L.; Ooba, N.; Tomaru, S.; Kurihara, T.; Kaino, T.; Kubota,
K.; Sasaki, S. J. Am. Chem. Soc. 1996, 118, 10389. (b)
Yamamoto, T.; Lee, B.-L.; Kokubo, H.; Kishida, H.; Hirota,
K.; Wakabayashi, T.; Okamoto, H. Macromol. Rapid Com-
mun. 2003, 24, 443. (c) Yasuda, T.; Imase, T.; Nakamura,
Y.; Yamamoto, T. Macromolecules 2005, 38, 4687.
(18) (a) Kim, S.-B.; Harada, K.; Yamamoto, T. Macromolecules
1998, 31, 988. (b) Berthelot, J.; Guette, C.; Desbene, P. L.;
Basselier, J. J.; Chaquin, P.; Masure, D. Can. J. Chem. 1989,
67, 2061.
(27) (a) Kost, D.; Frailich, M. THEOCHEM 1997, 398-399, 265.
(b) Crable, G. F.; Kearns, G. L. J. Phys. Chem. 1962, 66, 436.
(c) Streitwieser, Jr., A. J. Am. Chem. Soc. 1960, 82, 4123.
(28) (a) Pommerehne, J.; Vestweber, H.; Guss, W.; Mahrt, R. F.;
Ba¨ssler, H.; Porsch, M.; Daub, J. Adv. Mater. 1995, 7, 551.
(b) Liu, M. S.; Jiang, X.; Liu, S.; Herguth, P.; Jen, A. K.-Y.
Macromolecules 2002, 35, 3532. (c) Yamamoto, K.; Higuchi,
M.; Uchida, K.; Kojima, Y. Macromolecules 2002, 35, 5782.
(d) Ferraris, J. P.; Eissa, M. M.; Brotherston, I. D.; Loveday,
D. C. Chem. Mater. 1998, 10, 3528.
(29) Janietz, S.; Wedel, A. Adv. Mater. 1997, 9, 403.
(30) Chen, Z.-K.; Huang, W.; Wang, L.-H.; Kang, E.-T.; Chen, B.
J.; Lee, C. S.; Lee, S. T. Macromolecules 2000, 33, 9015.
(31) Weiss, K.; Beernink, G.; Do¨tz, F.; Birkner, A.; Mu¨llen, K.;
Wo¨ll, C. H. Angew. Chem., Int. Ed. 1999, 38, 3748.
(32) Tsubata, Y.; Suzuki, T.; Miyashi, T.; Yamashita, Y. J. Org.
Chem. 1992, 57, 6749.
(33) Coulson, D. R. Inorg. Synth. 1972, 13, 121.
(34) (a) Gore, P. H.; Hughes, G. K. J. Chem. Soc. 1959, 1615. (b)
Yamamoto, T.; Kurata, Y. Can. J. Chem. 1983, 61, 86.
(35) Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A.;
Burla, M.; Polidori, G.; Camalli, M. J. Appl. Crystallogr. 1994,
27, 435.
(19) Aqad, E.; Lakshmikantham, M. V.; Cave, M. P.; Broker, G.
A.; Rogers, R. D. Org. Lett. 2003, 5, 2519.
(20) Inbasekaran, M.; Wu, W.; Woo, E. P. U.S. Patent 5777070,
1998.
(36) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J. R.; Montgomery Jr., J. A.; Vreven,
T.; Kudin, K. N.; Burant, J. C.; Millam, J. M.; Iyengar, S. S.;
Tomasi, J.; Barone, V.; Mennucci, B.; Cossi, M.; Scalmani,
G.; Rega, N.; Petersson, G. A.; Nakatsuji, H.; Hada, M.;
Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.;
Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene, M.; Li,
X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.; Adamo, C.;
Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.;
Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Ayala,
P. Y.; Morokuma, K.; Voth, G. A.; Salvador, P.; Dannenberg,
J. J.; Zakrzewski, V. G.; Dapprich, S.; Daniels, A. D.; Strain,
M. C.; Farkas, O.; Malick, D. K.; Rabuck, A. D.; Raghava-
chari, K.; Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A.
G.; Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.;
Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R. L.; Fox,
D. J.; Keith, T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara,
A.; Challacombe, M.; Gill, P. M. W.; Johnson, B.; Chen, W.;
Wong, M. W.; Gonzalez, C.; Pople, J. A. Gaussian, Inc.,
Pittsburgh, PA, 2003.
(21) Aubert, P.-H.; Knipper, M.; Groenendaal, L.; Lutsen, L.;
Manca, J.; Vanderzande, D. Macromolecules 2004, 37, 4087.
(22) (a) Justin Thomas, K. R.; Lin, J. T.; Velusamy, M.; Tao, Y.-
T.; Chuen, C.-H. Adv. Funct. Mater. 2004, 14, 83. (b)
Yamamoto, T.; Lee, B.-L.; Nurulla, I.; Yasuda, T.; Yamaguchi,
I.; Wada, A.; Hirose, C.; Tasumi, M.; Sakamoto, A.; Koba-
yashi, E. J. Phys. Chem. B 2005, 109, 10605.
(23) (a) Reichardt, C. Chem. Rev. 1994, 94, 2319. (b) de Silva, A.
P.; Gunaratne, H. Q. N.; Gunnlaugsson, T.; Huxley, A. J. M.;
McCoy, C. P.; Rademacher, J. T.; Rice, T. E. Chem. Rev. 1997,
97, 1515.
(24) Yasuda, T.; Yamamoto, T. Macromolecules 2003, 36, 7513.
(25) (a) Parr, R. G.; Yang, W. Density-Functional Theory of Atoms
and Molecules; Oxford University Press: New York, 1989.
(b) Becke, A. D. J. Chem. Phys. 1993, 98, 5648. (c) Lee, C.;
Yang, W.; Parr, R. G. Phys. Rev. B 1988, 37, 785. (d)
Hariharan, P. C.; Pople, J. A. Theor. Chim. Acta 1973, 28,
213.
(26) Lias, S. G.; Bartmess, J. E.; Liebman, J. F.; Holmes, J. L.;
Levin, R. D.; Mallard, W. G. J. Phys. Chem. Ref. Data, Suppl.
1988, 17, 861.
MA051102I