Molecular design and synthesis of fluorinated polyethers toward organic materials with high dielectric constants and ferroelectricity

Article abstract of DOI:10.1246/bcsj.80.752

Molecular design and synthesis of organic ferroelectric materials with a -OCH₂CF₂CH₂O- moiety as the basic molecular structure were conducted in order to improve the high coercive field value of poly(vinylidene fluoride) (

Full text of DOI:10.1246/bcsj.80.752

752 Bull. Chem. Soc. Jpn. Vol. 80, No. 4, 752–757 (2007)
ꢀ 2007 The Chemical Society of Japan
Molecular Design and Synthesis of Fluorinated
Polyethers toward Organic Materials with
High Dielectric Constants and Ferroelectricity
ꢀ
Takashi Okano, Makiko Hiraishi, and Tomonori Mizutani
EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603
Received September 11, 2006; E-mail: okano@esi.nagoya-u.ac.jp
Molecular design and synthesis of organic ferroelectric materials with a –OCH2CF2CH2O– moiety as the basic
molecular structure were conducted in order to improve the high coercive field value of poly(vinylidene fluoride)
(PVDF). The synthesis of the designed molecules were based on the half ester 2,2-difluoro-1,3-propanediol N,N-dieth-
ylcarbamamic acid. The sequence of alkylation of alcohol, deprotection, and the second alkylation efficiently produced
the desired polyethers except in the case of the Williamson ether synthesis, which occurs between a fluorinated alcohol
and a fluorinated tosylate. The dielectric constants of the prepared polyethers at room temperature were relatively high,
although no ferroelectric properties were observed. Another method had functional groups at the end of the molecules
for intermolecular interaction. Hydrogen-bonded bisacetamide showed dielectric relaxation and ferroelectricity.
Ferroelectric materials are substances that respond to
changes in the applied electric field and memorize them, and
they are widely used in electric and electronic devices, such
F
F
O
O
as capacitors, transducers, actuators, ferroelectric random ac-
cess memory (FeRAM) devices, etc.1,2 Electrically and me-
chanically stable inorganic ferroelectric materials, such as
BaTiO3 and lead zirconate titanate (PZT), are commonly used
in such electronic devices. Organic ferroelectric materials3 are
also known, and the macromolecular PVDF and its copolymer
with trifluoroethene (PVDF–PTrFE) are superior to the inor-
ganic materials with regard to processability.4 However, since
the ferroelectric properties of PVDF or PVDF–PTrFE result
from parallel alignment of dipoles that are due to alternating
fluorinated and hydrogenated carbons of the polymer back-
bone, switching of the polarity requires rotation of the individ-
ual polymer molecules in the tangled van der Waals network.
Consequently, a higher voltage than that for inorganic materi-
als must be applied. Recently, a new organic ferroelectric ma-
terial consisting of cocrystals of ꢀ-conjugated molecules with
a low coercive field (Ec) value has been reported. Neverthe-
less, the ferroelectric phase only occurs at temperatures below
250 K.5
We have previously proposed an alternative molecular
structure, 2,2-difluoropropane-1,3-dioxy group (–OCH2CF2-
CH2O–) for organic materials with a high dielectric constant
and ferroelectric materials.6 The ether functionality forms a
dipole similar to the –CF2– bond as shown in Fig. 1. Although
the dipole moment is smaller than the PVDF skeleton, the flex-
ibility of the ether bonds7 is expected to assist molecular mo-
tion by alternating the electric field.
dipole moments
Fig. 1. Dipole alignment of 2,2-difluoropropane-1,3-dioxy
group structure under electric poling.
Results and Discussion
We have reported the synthesis of a m-xylylene-connected
polyether 1.6 In this molecule, there are two major dipoles
(–CF2–) and four minor dipoles (–O–) across the molecular
axis. Under an electric field, these dipoles can be aligned in
parallel as shown in Fig. 1. In a similar manner, an alkyl-
chain-terminated molecule 2, a tripod molecule 3, and a
molecule with integrated 2,2-difluoropropane-1,3-dioxy units
(four major dipoles and six minor dipoles: 4) were designed
(Chart 1). In the design of these molecules, the m-xylylene
backbone structure was incorporated in order to maintain a lin-
ear conformation of the polyether moieties, instead of employ-
ing the p-xylylene structure, which would cause an anti-paral-
lel alignment of the dipoles. We anticipated, in part, ꢀ-stack-
ing effects and also ease of etherification of benzyl bromides.
Preparation of the polyether 1 was started with the radical
addition of 2,2-difluoroethenyl N,N-diethylcarbamate (5) to
2,2-dimethyl-1,3-dioxolane,8 and the half-protected 2,2-di-
fluoro-1,3-propanediol 6,6 which is an important synthetic in-
termediate, was used. For the preparative scale experiments,
the preparation sequence for 6 was slightly changed, as shown
in Scheme 1. The radical reaction of the fluorinated olefin 5
was initiated by dibenzoyl peroxide in 2-ethyl-2-methyl-1,3-
In this paper, we report the molecular design and synthesis
of fluorinated polyethers with relatively high dielectric con-
stants. While most of the synthesized materials were not ferro-
electric, a hydrogen-bonded compound showed dielectric re-
laxation and ferroelectricity at room temperature.
Published on the web April 13, 2007; doi:10.1246/bcsj.80.752

T. Okano et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 4 (2007)
753
F
F
F
F
F
F
Ph
Ph
O
O
F
O
O
F
Ph
O
F
1
F
O
O
O
F
O
O
F
2
F
F
F
Ph
O
O
O
O
3
O
F
F
F
F
F
F
F
Ph
O
O
O
O
Ph
O
4
Ph
Chart 1.
1) HCl/CH3OH
2) NaIO4
PhCO2OCOPh
F
F
OCONEt2
F
F
O
O
∆
OCONEt2
O
O
HO
+
3) NaHCO3
4) NaBH4
66%
OCONEt2
H
82%
6
5
F
F
7
1) KOH / iPrOH
1) NaH/DMF
2) C4H9I
2) m-(BrCH2)2C6H4
F
F
2
O
OCONEt2
6
49%
52%
8
1) NaH/THF
2) PhCH2Br
1) NaH / THF
2) 1,3,5-(BrCH2)3C6H3
F
F
3
3) KOH / iPr-OH
Ph
O
OH
66%
6
6
9
55%
NaH / DMF r. t.
F
F
F
F
OH
HO
O
O
10
1) NaH/THF
2) TsCl
DMF refl.
16%
F
F
4
Ph
O
OTs
9
61%
11
Scheme 1.
dioxolane, which can be readily prepared from 2-butanone and
ethylene glycol,9 and gave a 1:1 mixture of the addition prod-
uct stereoisomers 7 in 82% yield. The roughly isolated stereo-
isomeric mixture of adducts 7 was treated with hydrochloric
acid in methanol, sodium periodate for glycol cleavage,
NaHCO3 for neutralization, and finally NaBH4 for reduction
of the aldehyde in a one-pot reaction to give monoalcohol 6
in 66% yield.
For the preparation of alkyl-chain-terminated compound 2,
alcohol 6 was first alkylated with NaH and 1-iodobutane,
deprotected with alkaline hydrolysis, and then reacted with
NaH and m-bis(bromomethyl)benzene (52%). Tripod molecule
3 was synthesized starting from alcohol 6 to convert it into
alcohol 9 (55%), which was then successively reacted with
1,3,5-tris(bromomethyl)benzene (66%). In the case of the syn-
thesis of polyether 4, alcohol 9 was first tosylated, affording
tosylate 11, and 11 was reacted with previously reported diol
10.6 While the reaction of sodium alkoxide of diol 10 and
tosylate 11 is a typical condition of the Williamson ether syn-
thesis, it was unusually sluggish because of the retarded reac-
tivities of both the reactants which had electron-withdrawing
fluorine substituents. The reaction in refluxing DMF gave
polyether 4 in low yield (16%).
In Table 1, the relative dielectric constants of polyethers
1–4 recorded at room temperature (100 Hz) are summarized.
The experimental dielectric constants were corrected using
the value for o-dichlorobenzene as a standard. As expected,
all four polyethers 1–4 had relatively high dielectric constants
and were comparable to a typical high-dielectric-constant
compound, nitrobenzene. This implies that molecular design
of the organic materials with a high dielectric constant based
on the 2,2-difluoropropane-1,3-dioxy structure is reliable.

754 Bull. Chem. Soc. Jpn. Vol. 80, No. 4 (2007)
Ferroelectric Fluorinated Polyether
Since the dielectric constants of 2,2-difluoropropane-1,3-dioxy
containing compounds 1–4 were all comparable and independ-
ent of the molecular structure, the contribution of the fluorinat-
ed ether structure to the high dielectric constants was conclud-
ed to be determined by the content of the fluorinated ether moi-
ety in the molecule.
the intermolecular polar interactions. 4-Nitrobenzylation of
diol 10 was carried out by treatment with 4-nitrobenzyl bro-
mide and Ag2O in refluxing benzene to give 12 in 31% yield.12
Diamine 13 was obtained by the catalytic hydrogenation of 12
(58%) with palladium on carbon (Pd/C), and acetylation of 13
with acetic anhydride yielded bisacetamide 14 (73%). In com-
parison to the prototype compound 1, bifunctional compounds
12–14 have the higher viscosities at room temperature indicat-
ing enhanced intermolecular interactions. Particularly, bisace-
tamide 14 is an extremely viscous fluid at room temperature re-
sulting from a strong hydrogen-bonding, which appears strong-
er than that of aniline derivative 13 on the basis of the estimat-
ed hydrogen-bond energies of aniline13 and acetanilide.14
In Table 1, the dielectric constants of 12–14 are also shown
(100 Hz). Unexpectedly, the dielectric constants of nitro and
amino compounds 12 and 13 were lower than 1, probably be-
cause of the unfavorable dipoles resulting from the added
functional groups. However, bisacetamide 14 ("0 ¼ 43) had
the highest dielectric constant among all our compounds.
The frequency dependence of the dielectric constants of
12–14 and 1 were evaluated at 100 Hz, 1 kHz, 10 kHz, and
100 kHz and are summarized in Fig. 2. The dielectric constants
of 1, 12, and 13 were affected slightly by changes in the mea-
For the organic ferroelectric materials, the dielectric con-
stants depend on the measuring frequency.10 However, the di-
electric constants of compounds 1–4 and the applied frequency
(10–100 kHz) showed almost no correlation. These compounds
are all light oil materials at room temperature because of the
weak intermolecular interactions, which are peculiar to fluo-
rinated organic compounds.11 In the case of the PVDF, the ac-
cumulated van der Waals interaction of individual polymer
molecules forces the dipole-aligned conformation to be main-
tained against electric field switching (high Ec values).3 This
suggests a strategy for the molecular design of new organic
ferroelectric materials. If each molecule has two or more inter-
active functional groups that are stronger than the van der
Waals bonding, the motion of the dipole-aligned molecules
should be restricted, and thus a bulk ferroelectric property is
expected. As a basic molecular structure, we selected poly-
ether 1. Instead of the benzyl groups in compound 1, 4-nitro-
benzyl (12), 4-aminobenzyl (13), and 4-acetamidobenzyl (14)
groups (see Scheme 2), were employed as terminal groups for
50
Table 1. Relative Dielectric Constants of Benzene Deriva-
tives with –OCH2CF2CH2O– Substructure at Room Tem-
perature (100 Hz)
40
(a)
Relative dielectric
constants ("0)
(b)
Entry
Compounds
30
1
2
3
4
5
6
7
1
2
3
4
12
13
14
36.8
38.7
36.1
34.1
29.1
21.9
43.7
(c)
20
(d)
10
102
103
104
105
o-Dichlorobenzene
(experimental standard)
Nitrobenzene
8
9
10.12a)
34.74a)
Frequency / Hz
Fig. 2. Frequency dependence of relative dielectric con-
stants of ethers (a) 1, (b) 12, (c) 13, and (d) 14.
a) Literature values (Ref. 16).
Ag2O
NO2
O2N
F
F
F F
BrCH2C6H4NO2
31%
O
O
O
O
10
12
H2
NH2
H2N
F
F
F
F
F
F
F
F
Pd/C EtOH
O
O
O
O
O
O
O
O
58%
13
14
Ac2O
Et3N
NHAc
AcHN
73%
Scheme 2.

T. Okano et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 4 (2007)
755
Experimental
6
4
1H NMR spectra were recorded on a 300 MHz spectrometer
with Si(CH3)4 as an internal standard, and 19F NMR spectra were
recorded on a 282 MHz spectrometer with CF3COOEt as an inter-
nal standard (ꢁ ꢂ75:75 from CFCl3).
Pr
2
4-[2-(N,N-Diethylcarbamoyloxy)-1,1-difluoroethyl]-2-ethyl-
2-methyl-1,3-dioxolane (7). To a refluxing solution of 2,2-di-
fluoroethenyl N,N-diethylcarbamate (5) (12.6 g, 70 mmol) in 2-
ethyl-2-methyl-1,3-dioxolane (220 mL, 1.76 mol), solid dibenzoyl
peroxide was added portionwise in a rate of 20 mg in every 5–
10 min (totally 2.7 g, 11 mmol). When the amount of unreacted
5 was less than 10% of the initial amount, the solvent was recov-
ered by distillation. The cooled residue was dissolved in Et2O,
and the solution was washed with saturated aqueous NaHCO3 to
remove benzoic acid. The solution was dried over MgSO4, and
the solvent was removed under reduced pressure. The residue
was chromatographed on an SiO2 column (hexane:AcOEt = 5:1)
to give a diastereomer mixture (1:1) of dioxolane 7 as a colorless
oil: 17.0 g (82%); IR (neat film) 2977, 2937, 1715, 1429, 1276,
0
Ec
-2
-4
-6
-20 -15 -10 -5
0
5
10 15 20
E / MV m-1
Fig. 3. Electric field–polarization profile of bisamide 14.
surement frequency. However, the dielectric constant of bis-
acetamide 14 considerably decreased from "0 ¼ 43 at 100 Hz
to "0 ¼ 19 at 100 kHz. Such dielectric relaxation behavior
has often been observed in ferroelectric liquid crystals15 and
suggests that the molecular motion is restricted at higher fre-
quencies by the intermolecular hydrogen bonding.
1
1166, 1084 cmꢂ1; H NMR (CDCl3) ꢁ 0.92 (1.5H, t, J ¼ 7:5 Hz),
0.94 (1.5H, t, J ¼ 7:5 Hz), 1.14 (6H, t, J ¼ 7:2 Hz), 1.31 (1.5H, s),
1.38 (1.5H, s), 1.61–1.76 (2H, m), 3.24–3.36 (4H, m), 3.88–3.99
(2H, m), 4.08–4.52 (3H, m); 19F NMR (CDCl3) ꢁ ꢂ115:2 (1F ꢃ
0.5, dtd, J ¼ 261, 16, 5 Hz), ꢂ115:9 (1F ꢃ 0.5, dtd, J ¼ 261, 17,
5 Hz), ꢂ123:1 (1F ꢃ 0.5, dddd, J ¼ 261, 22, 12, 7 Hz), ꢂ123:2
(1F ꢃ 0.5, dddd, J ¼ 261, 17, 10, 7 Hz); EI-MS m=z (%) 295
(0.2, Mþ), 280 (11), 266 (29), 100 (100), 73 (11), 72 (20), 57
(30), 56 (20), 55 (14). Anal. Found: C, 53.02; H, 8.04; N, 4.91%.
Calcd for C13H23F2NO4: C, 52.87; H, 7.85; N, 4.74%.
The ferroelectric property of the most promissing compound
14 was evaluated using a cell between indium tin oxide (ITO)
glass electrodes with a 25-mm-thick film spacer of poly(ethyl-
ene terephthalate) (PET) at room temperature in the range of
ꢁ450 V bias voltages at 1 Hz. As shown in Fig. 3, a ferroelec-
tric hysteresis loop of the polarization–electric field (P–E)
characteristic was observed at this frequency. Unfortunately,
the polarization did not reach a saturated value due to an insu-
lation failure in the liquid film at higher bias voltages. Thus,
the residual polarization (Pr ¼ 3:3 mC mꢂ2) was considerably
smaller than PVDF (ca. 60 mC mꢂ2),3 but the coercive field
(Ec ¼ 8:2 MV mꢂ1) was close to the saturated value according
to the P–E characteristics profile of PVDF.3 As expected, the
effect of substituting part of the difluoromethylene groups of
the PVDF molecular structure with oxygen atoms caused a
decrease in the coercive field, which was ca. 20% of that of
PVDF (Ec ¼ 45 MV mꢂ1).3
2,2-Difluoro-3-(N,N-diethylcarbamoyoxy)-1-propanol (6).
Dioxolane 7 (16.3 g, 55 mmol) was dissolved in methanol (100
mL), and conc. HCl (12 mL) was added to the resulting solution.
The solution was stirred overnight at room temperature. To the so-
lution, NaIO4 (14 g, 65 mmol) and water (20 mL) were added, and
the mixture was stirred for 3 h at room temperature. To the mix-
ture, solid NaHCO3 was carefully added portionwise to neutralize
the mixture. Solid NaBH4 (4 g, 106 mmol) was added portionwise
to the ice-cooled mixture. The resulting mixture was stirred for 30
min at room temperature. After filtration and removal of the sol-
vent under reduced pressure, the residue was dissolved to water.
The aqueous solution was extracted with Et2O, and the combined
extracts were dried over MgSO4. The solvent was removed under
reduced pressure, and the residue was distilled to obtain alcohol 6
as a colorless oil: 7.65 g (66%); bp 124–126 ꢄC (3 mmHg). Spec-
tral data of this material were identical with an authentic sample.6
m-Bis[(3-butoxy-2,2-difluoropropoxy)methyl]benzene (2).
NaH (60% oil dispersion, 1.00 g, 25 mmol) was suspended to an-
hydrous DMF (10 mL), and then to the ice-cooled suspension, al-
cohol 6 (4.06 g, 19 mmol) dissolved in anhydrous DMF (20 mL)
was added dropwise under N2 atmosphere. After H2 evolution
had stopped, 1-iodobutane (4.3 mL, 39 mmol) was added, and
the resulting mixture was refluxed for 8 h. The cooled mixture
was poured onto water and extracted with Et2O. The combined ex-
tracts were dried over MgSO4, and the solvent was removed under
reduced pressure. The residue was chromatographed on an SiO2
column (hexane:EtOAc = 5:1) to give pure 2,2-difluoro-4-oxaoc-
tyl N,N-diethylcarbamate (8): 2.51 g (49%); IR (neat film) 2963,
In summary, we designed a fluorinated polyether structure
for preparing organic ferroelectric materials. The designed
2,2-difluoropropane-1,3-dioxy group structure was highly ori-
ented under an electric field, while a disorder of the dipole
alignment rapidly occurred when the applied electric field
was switched off. Intermolecular hydrogen bonding helped
to maintain the ordered structure and bisacetamide 14 showed
ferroelectricity at room temperature. For fine tuning the molec-
ular design of this type of new organic ferroelectric materials,
it is essential that the following two molecular structural fac-
tors must be balanced: 1) there must be a high population of
the flexible –OCH2CF2CH2O– moieties for the alignment of
the dipoles, and 2) it must have relatively constrained intermo-
lecular bonds that intervene in the rapid molecular motion. The
lower coercive field value of the non-crystalline organic ferro-
electric material observed here is an important factor for appli-
cation in low-voltage operating electronic devices used at am-
bient temperatures.
2917, 1713, 1428, 1273, 1166, 1131 cmꢂ1 1H NMR (CDCl3) ꢁ
;
0.91 (3H, t, J ¼ 7:5 Hz), 1.14 (6H, t, J ¼ 7:2 Hz), 1.37 (2H, sex-
tet, J ¼ 7:8 Hz), 1.57 (2H, quintet, J ¼ 7:5 Hz), 3.26–3.30 (4H,
m), 3.54 (2H, t, J ¼ 6:6 Hz), 3.68 (2H, t, J ¼ 12:6 Hz), 4.37

756 Bull. Chem. Soc. Jpn. Vol. 80, No. 4 (2007)
Ferroelectric Fluorinated Polyether
2936, 1455, 1299, 1211, 1106, 1078, 906, 741, 699 cmꢂ1
(2H, t, J ¼ 12:9 Hz); 19F NMR (CDCl3) ꢁ ꢂ113:6 (quintet, J ¼
12 Hz); EI-MS m=z (%) 267 (0.5, Mþ), 180 (24), 116 (23), 100
(20), 72 (12), 58 (16), 57 (100). Anal. Found: C, 53.99; H, 8.86;
N, 5.19%. Calcd for C12H23F2NO3: C, 53.92; H, 8.67; N, 5.24%.
This carbamate 8 (2.51 g, 9.4 mmol) was dissolved in 2-propa-
nol (70 mL). To the solution, KOH (5.60 g, 100 mmol) was added,
and the resulting mixture was refluxed for 20 h. To the mixture,
water was added, and the solution was neutralized by addition
of dilute hydrochloric acid. The mixture was extracted with
EtOAc, and the combined extracts were dried over Na2SO4. The
solvent was removed under reduced pressure to give crude 2,2-di-
fluoro-4-oxaoctan-1-ol, which was used at the next step without
purification: 1.22 g (77%): 1H NMR (CDCl3) ꢁ 0.92 (3H, t, J ¼
7:2 Hz), 1.37 (2H, sextet, J ¼ 7:2 Hz), 1.58 (2H, quintet, J ¼ 7:2
Hz), 3.55 (2H, t, J ¼ 6:6 Hz), 3.74 (2H, t, J ¼ 12:3 Hz), 3.87 (2H,
t, J ¼ 12:9 Hz); 19F NMR (CDCl3) ꢁ ꢂ115:1 (quintet, J ¼ 12 Hz).
NaH (60% oil dispersion, 200 mg, 5 mmol) was suspended in
anhydrous DMF (5 mL). To the ice-cooled mixture, a solution of
the above alcohol (1.0 g, 5.9 mmol) in anhydrous DMF (5 mL) was
added. After evolution of H2 had stopped, a solution of ꢂ,ꢂ0-
dibromo-m-xylene (530 mg, 2 mmol) in anhydrous DMF (5 mL)
was added at room temperature. The resulting mixture was stirred
overnight at room temperature. The mixture was diluted with wa-
ter and extracted with Et2O. The combined extracts were dried
with MgSO4, and the solvent was removed under reduced pres-
sure. The residue was chromatographed on an SiO2 column
(hexane:EtOAc = 10:1) to give polyether 2 as a colorless oil:
587 mg (67%); IR (neat film) 2977, 2917, 2873, 1461, 1295, 1117,
988, 792, 701 cmꢂ1; 1H NMR (CDCl3) ꢁ 0.91 (6H, t, J ¼ 7:5 Hz),
1.36 (4H, sextet, J ¼ 7:5 Hz), 1.56 (4H, quintet, J ¼ 7:5 Hz), 3.53
(4H, t, J ¼ 6:6 Hz), 3.71 (4H, t, J ¼ 12:6 Hz), 3.74 (4H, t, J ¼
12:6 Hz), 4.63 (4H, s), 7.26–7.36 (4H, m); 19F NMR (CDCl3) ꢁ
ꢂ113:1 (quintet, J ¼ 12 Hz); EI-MS m=z (%) 270 (41), 213
(20), 151 (29), 119 (100). Anal. Found: C, 60.53; H, 7.99%. Calcd
for C22H34F4O4: C, 60.26; H, 7.82%.
;
1H NMR (CDCl3) ꢁ 1.98 (1H, t, J ¼ 7:1 Hz), 3.77 (2H, t, J ¼ 12:5
Hz), 3.89 (2H, t, J ¼ 12:5 Hz), 4.63 (2H, s), 7.30–7.40 (5H, m);
19F NMR (CDCl3) ꢁ ꢂ115:3 (quintet, J ¼ 12 Hz); EI-MS m=z
(%) 202 (59, Mþ), 108 (11), 107 (78), 92 (23), 91 (100), 79
(30), 77 (24), 65 (42), 51(35). Anal. Found: C, 59.72; H, 6.34%.
Calcd for C10H12F2O2: C, 59.40; H, 5.98%.
1,3,5-Tris(4,4-difluoro-7-phenyl-2,6-dioxaheptyl)benzene (3).
Alcohol 9 (1.65 g, 8.2 mmol) and NaH (60% oil dispersion: 250
mg, 6.2 mmol) were dissolved in anhydrous THF (5 mL). After
H2 evolution had stopped, a THF solution (10 mL) of 1,3,5-tris-
(bromomethyl)benzene (712 mg, 2.0 mmol) was added dropwise.
The resulting mixture was stirred for 24 h. A small amount of wa-
ter was added into the mixture, and the mixture was neutralized
with hydrochloric acid. The mixture was extracted with Et2O.
The combined extracts were dried over Na2SO4, and the solvent
was removed under reduced pressure. The residue was chromato-
graphed on an SiO2 column (hexane:EtOAc = 5:2) to give pure
polyether 3 as a colorless oil: 956 mg (66%); IR (neat film) 3032,
2917, 2857, 1604, 1454, 1109, 1000, 740, 699 cmꢂ1 1H NMR
;
(CDCl3) ꢁ 3.78 (6H, t, J ¼ 12:5 Hz), 3.76 (6H, t, J ¼ 12:5 Hz),
4.57 (6H, s), 4.60 (6H, s), 7.20 (3H, s), 7.28–7.35 (15H, m);
19F NMR (CDCl3) ꢁ ꢂ112:9 (quintet, J ¼ 12 Hz); EI-MS m=z
(%) 517 (2.2), 427 (20), 337 (20), 317 (32), 303 (23), 227 (19),
209 (12), 202 (15), 201 (100), 193 (15), 181 (14), 123 (14), 119
(12), 107 (39), 105 (15). Anal. Found: C, 64.73; H, 6.06%. Calcd
for C39H42F6O6: C, 64.99; H, 5.87%.
1,3-Bis(4,4,8,8-tetrafluoro-11-phenyl-2,6,10-trioxaundecyl)-
benzene (4). To an ice-cooled suspension of NaH (60% oil dis-
persion: 1.08 g, 27 mmol) in anhydrous THF (15 mL), a solution of
alcohol 9 (5.16 g, 25 mmol) in THF (15 mL) was added. After evo-
lution of hydrogen stopped, a solution of p-toluenesulfonyl chlo-
ride (6.18 g, 32 mmol) in THF (20 mL) was added, and the result-
ing mixture was stirred overnight. The mixture was diluted with
water and extracted with Et2O. The combined extracts were dried
with MgSO4, and the solvent was removed under reduced pres-
sure. The crude tosylate 11 was used without further purification
(5.56 g, 61%).
2,2-Difluoro-5-phenyl-4-oxapentan-1-ol (9). Alcohol 6 (4.64
g, 22 mmol) and NaH (60% oil dispersion: 1.07 g, 27 mmol) were
dissolved in THF (20 mL). After H2 evolution had stopped, benzyl
bromide (4.2 g, 24 mmol) was added dropwise under ice-cooling.
The resulting mixture was stirred at room temperature overnight.
A small amount of water was added into the mixture, and the mix-
ture was extracted with Et2O. The combined extracts were dried
over Na2SO4, and the solvent was removed under reduced pres-
sure. The residual mixture was purified with SiO2 column chroma-
tography (hexane:EtOAc = 5:1) to afford 2,2-difluoro-5-phenyl-
4-oxapentyl N,N-diethylcarbamate (4.56 g; 69%): colorless oil;
IR (neat film) 2976, 1713, 1479, 1429, 1275, 1167, 1097, 699
Already reported ꢃ,ꢃ,ꢃ0,ꢃ0-tetrafluoro-1,3-benzenebis(ꢁ-oxa-
pentanol) (10) (1.95 g, 6.0 mmol) and NaH (60% oil dispersion:
520 mg, 13 mmol) were dissolved in anhydrous DMF (10 mL).
To the mixture, a DMF solution (40 mL) of above-mentioned to-
sylate (5.56 g, ca. 15 mmol) was added dropwise at room temper-
ature. The mixture was refluxed for 21 h. A small amount of water
was added into the mixture, and the mixture was neutralized with
hydrochloric acid. The mixture was extracted with Et2O. The
combined extracts were dried over Na2SO4, and the solvent was
removed under reduced pressure. The residue was successively
chromatographed on SiO2 columns (hexane:EtOAc = 10:1–5:1)
to give pure polyether 4 as a pale yellow oil. Yield: 650 mg
(16%); IR (neat film) 3032, 2977, 2917, 2874, 1454, 1122, 913,
cmꢂ1
;
1H NMR (CDCl3) ꢁ 1.10 (6H, t, J ¼ 7:5 Hz), 3.18–3.31
(4H, m), 3.71 (2H, t, J ¼ 12:5 Hz), 4.40 (2H, t, J ¼ 12:8 Hz),
4.62 (2H, s), 7.27–7.38 (5H, m); 19F NMR (CDCl3) ꢁ ꢂ113:7
(quintet, J ¼ 12 Hz); EI-MS m=z (%) 301 (0.12, Mþ), 195 (10),
180 (28), 160 (21), 116 (34), 100 (26), 91 (100), 72 (11). Anal.
Found: C, 59.72; H, 7.19; N, 4.50%. Calcd for C15H21F2NO3:
C, 59.79; H, 7.02; N, 4.65%.
738, 698 cmꢂ1
;
1H NMR (CDCl3) ꢁ 3.72 (8H, t, J ¼ 12:4 Hz),
3.73 (8H, t, J ¼ 12:6 Hz), 4.63 (8H, s), 7.30–7.36 (14H, m);
19F NMR (CDCl3) ꢁ ꢂ113:2 (quintet, J ¼ 12 Hz); EI-MS m=z
(%) 295 (29, C6H5CH2(OCH2CF2CH2)2Oþ), 201 (50), 183 (33),
107 (100), 105 (41). Anal. Found: C, 59.04; H, 5.77%. Calcd
for C34H38F8O6: C, 58.79; H, 5.51%.
This benzyl derivative (7.0 g, 23 mmol) was dissolved in 2-
propanol (30 mL). To the solution, KOH (5.60 g, 100 mmol) was
added, and the resulting mixture was refluxed for 24 h. To the
mixture, water was added, and the mixture was extracted with
EtOAc. The combined extracts were dried over Na2SO4, and the
solvent was removed under reduced pressure. The residue was
chromatographed on an SiO2 column (hexane:EtOAc = 5:1) to
obtain pure alcohol 9: 3.70 g (79%): IR (neat film) 3401, 3066,
1,3-Bis[4,4-difluoro-7-(4-nitrophenyl)-2,6-dioxaheptyl]ben-
zene (12). Diol 10 (1.0 g, 3.1 mmol) and p-nitrobenzyl bromide
(2.6 g, 12 mmol) was dissolved in benzene (15 mL), and then
Ag2O (2.3 g, 10 mmol) was added in one portion. The mixture
was refluxed with vigorous stirring for 36 h. The cooled mixture

T. Okano et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 4 (2007)
757
was filtered, and the solvent of the filtrate was removed under re-
duced pressure. The residue was chromatographed on an SiO2 col-
umn (hexane:EtOAc = 5:1–1:1) to give pure polyether 13 as a
pale orange-colored highly viscous liquid: 567 mg (31%); IR (neat
film) 3077, 2928, 2857, 1610, 1526, 1460, 1347, 1118, 1022, 916,
and they were recorded on an impedance analyzer at several fre-
quencies at room temperature. The acquired dielectric constant
data were calibrated by using the literature data for o-dichloroben-
zene ("0 ¼ 10:12).16 The cell with a 25-mm-thick film spacer was
also used to obtain a P–E field characteristic of bisacetamide 14
at 1 Hz by applying several bias voltages until 450 V at room tem-
perature.
855, 810, 749, 697 cmꢂ1
;
1H NMR (CDCl3) ꢁ 3.78 (4H, t, J ¼
12:5 Hz), 3.83 (4H, t, J ¼ 12:5 Hz), 4.62 (4H, s), 4.71 (4H, s),
7.25–7.36 (4H, m), 7.46 (4H, d, J ¼ 8:4 Hz), 8.18 (4H, d, J ¼ 8:4
Hz); 19F NMR (CDCl3) ꢁ ꢂ112:9 (quintet, J ¼ 12 Hz); EI-MS
m=z (%) 230 (70), 152 (52), 106 (92), 104 (100). Anal. Found:
C, 56.60; H, 4.89; N, 4.63%. Calcd for C28H28F4N2O8: C, 56.38;
H, 4.73; N, 4.70%.
We thank Mr. Hironobu Matsumoto, Toyo Corporation, for
the measurement of P–E characteristics. This work was par-
tially supported by the Ministry of Education, Culture, Sports,
Science and Technology, Grant-in-Aid for Exploratory Re-
search, No. 14655334, 2002.
1,3-Bis[7-(4-aminophenyl)-4,4-difluoro-2,6-dioxaheptyl]ben-
zene (13). Nitrobenzyl derivative 12 (567 mg, 0.95 mmol) was
dissolved in EtOAc (5 mL). To the solution, palladium/carbon
(10% Pd, 11 mg, 0.01 mmol) was added. The resulting mixture
was vigorously stirred overnight under H2 (1 atm) at room temper-
ature. The mixture was filtered, and the solvent was removed un-
der reduced pressure. The residue was almost pure diamine 13 (a
pale orange-colored highly viscous liquid): 300 mg (58%); IR
(neat film) 3460, 3373, 3226, 3032, 2917, 2875, 1622, 1518, 1454,
References
1
a) E. Fatuzzo, W. J. Merz, Ferroelectricity, North-Holland
Publishing, Amsterdam, 1967. b) M. E. Lines, A. M. Glass,
Principles and Applications of Ferroelectrics and Related
Materials, Clarendon Press, Oxford, 1977.
2
Ferroelectric Random Access Memories: Fundamentals
1290, 1103, 994, 916, 827 cmꢂ1
;
1H NMR (CDCl3) ꢁ 3.02 (4H,
and Applications, ed. by H. Ishikawa, M. Okayama, Y. Arimori,
Springer-Verlag, Berlin, 2004.
brs), 3.70 (4H, t, J ¼ 12:4 Hz), 3.75 (4H, t, J ¼ 12:5 Hz), 4.48
(4H, s), 4.58 (4H, s), 6.65 (4H, d, J ¼ 8:4 Hz), 7.10 (4H, d, J ¼
8:4 Hz), 7.23–7.36 (4H, m); 19F NMR (CDCl3) ꢁ ꢂ112:8 (quintet,
J ¼ 12 Hz); EI-MS m=z (%) 536 (3.9, Mþ), 430 (17), 216 (21),
123 (18), 106 (100). Anal. Found: C, 62.53; H, 6.05; N, 5.19%.
Calcd for C28H32F4N2O4: C, 62.68; H, 6.01; N, 5.22%.
3
4
T. Furukawa, Phase Transitions 1989, 18, 143.
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benzene (14). Diamine 13 (38 mg, 0.07 mmol) was dissolved
in EtOAc (3 mL). To the solution, acetic anhydride (10 mL, 0.10
mmol) and triethylamine (10 mL, 0.08 mmol) were added, and
the resulting solution was stirred at room temperature for 2 h.
The solution was washed with a small amount of H2O and dried
with Na2SO4. After removal of the solvent, the residue was chro-
matographed on an SiO2 column (EtOAc) to give pure 14 as a
faintly yellow and highly dense liquid: 32 mg (73%); IR (neat
film) 3307, 3193, 3124, 2961, 2921, 2872, 1668, 1604, 1537,
1410, 1316, 1106, 1004, 827, 791 cmꢂ1; 1H NMR (CDCl3) ꢁ 2.17
(6H, s), 3.72 (4H, t, J ¼ 12:6 Hz), 3.75 (4H, t, J ¼ 12:5 Hz), 4.55
(4H, s), 4.57 (4H, s), 7.23 (4H, d, J ¼ 8:5 Hz), 7.24 (2H, br s),
7.28–7.35 (4H, m), 7.46 (4H, d, J ¼ 8:5 Hz); 19F NMR (CDCl3)
ꢁ ꢂ112:8 (quintet, J ¼ 12 Hz); EI-MS m=z (%) 621 (0.7), 620
(0.6, Mþ), 148 (28), 136 (15), 119 (24), 106 (100). Anal. Found:
C, 61.79; H, 6.15; N, 4.36%. Calcd for C32H36F4N2O6: C, 61.93;
H, 5.85; N, 4.51%.
6
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Measurement of Relative Dielectric Constants of Com-
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¨