Banana-shaped liquid crystals based on 2,7-dihydroxynaphthalene derivatives

Article abstract of DOI:10.1134/S1070363215030081

Abstract New mono- and dichloro-substituted derivatives of 2,7-dihydroxynaphthalene were synthesized, and their mesomorphic properties were investigated. Bis-2,7-[4-(4-n-alkoxybenzoyloxy)-3-chlorobenzoyloxy]-naphthalenes with the terminal nonyloxy or decyloxy group were found to form nematic and B₁ mesophases; the homolog with dodecyloxy group formed B₂ modification exclusively. Bis-2,7-[4-(4-n-alkoxybenzoyloxy)-3,5-dichlorobenzoyloxy]naphthalenes occurred to be non-mesomorphic and vitrified from isotropic liquid.

Full text of DOI:10.1134/S1070363215030081

ISSN 1070-3632, Russian Journal of General Chemistry, 2015, Vol. 85, No. 3, pp. 577–583. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © L.G. Derkach, N.S. Novikova, E. Gorecka, 2015, published in Zhurnal Obshchei Khimii, 2015, Vol. 85, No. 3, pp. 413–419.
Banana-Shaped Liquid Crystals Based
on 2,7-Dihydroxynaphthalene Derivatives
L. G. Derkacha, N. S. Novikovaa, and E. Goreckab
a Bogatskii Physicochemical Institute, National Academy of Sciences of Ukraine,
Lyustdorfskaya Doroga 86, Odessa, 65080 Ukraine
e-mail: nadyanovikova@rambler.ru
b University of Warsaw, Warsaw, Poland
Received October 13, 2014
Abstract—New mono- and dichloro-substituted derivatives of 2,7-dihydroxynaphthalene were synthesized,
and their mesomorphic properties were investigated. Bis-2,7-[4-(4-n-alkoxybenzoyloxy)-3-chlorobenzoyloxy]-
naphthalenes with the terminal nonyloxy or decyloxy group were found to form nematic and B1 mesophases;
the homolog with dodecyloxy group formed B2 modification exclusively. Bis-2,7-[4-(4-n-alkoxybenzoyloxy)-
3,5-dichlorobenzoyloxy]naphthalenes occurred to be non-mesomorphic and vitrified from isotropic liquid.
Keywords: 2,7-dihydroxynaphthalene derivatives, mesomorphic properties, banana-shaped liquid crystals
DOI: 10.1134/S1070363215030081
Banana-shaped compounds are known to form
seven modifications of biaxial smectic mesophase [1].
The eighth modification has been described in [2].
Compounds which can form mesophase B2 with
ferroelectric properties and possess twisting ability
have practical importance for increasing the response
speed of the liquid-crystal displays. Therefore the
study of the relation between the structure of the
banana-shaped compounds and their ability to form
mesophase B2 is an urgent problem.
diester containing a terminal nonyloxy group and
forming nematic mesophase has been reported in [5].
The increase in the terminal group length up to
14 carbon atoms caused appearance of unidentified
smectic phase together with the nematic one [6]. The
presence of a double bond in the terminal decyloxy
group reduced the temperature range of the nematic
phase existence [7].
1-Chloro-2,7-dihydroxynaphthalene diesters are
known to form mesophase B2 if the terminal alkoxy
group contained 12 carbon atoms [8].
It is known that introduction of the fluorine atom
into the structure of banana-shaped compounds usually
leads to the appearance of phase B2. The synthesis and
mesomorphic properties of unsubstituted and fluorine-
substituted 2,7-dihydroxynaphthalene diesters have
been reported in [3]. The majority of the compounds
form mesophases B1 and B2. For the fluoro-substituted
diesters the reduction of the phase-transition tempera-
tures was observed; their lower homologs form only a
nematic phase.
In the present work the method of synthesis of
banana-shaped 2,7-dihydroxynaphthalene esters con-
taining chloro-substituted aromatic rings was
developed; moreover, the impact of the substituents
structure on mesogenic property of the molecules was
investigated.
The target 2,7-dihydroxynaphthalene derivatives
VIIIa–VIIIc and IXa–IXd were prepared by
esterification of 4-(4-n-alkoxybenzoyloxy)-3-chloro-
The same researchers [4] investigated mesomorphic
properties of 2,7-dihydroxynaphthalene diesters con-
taining a fluoro-substituted aromatic moiety. In both
cases the B2 phase appeared if the terminal alkoxy
group contained no less than 10–11 carbon atoms. The
mesomorphism of 4-chloro-1,3-dihydroxybenzene
and
4-(4-n-alkoxybenzoyloxy)-3,5-dichlorobenzoic
acids VIa–VIc and VIIa–VIId using carbodiimide
procedure. 3-Chloro- and 3,5-dichlorobenzoic acids II
and III were prepared by the known method [9]. 4-
Alkoxybenzoic acid chlorides Va–Vd were obtained
577

578
DERKACH et al.
Scheme 1.
HO
HO
COOH
H2n+1CnO
COOH
I
IV
HCl
SOCl2
H2O2
X
Y
COOH
H2n+1CnO
COCl
Vа−Vd
II, III
X
Y
O
H2n+1CnO
O
COOH
VI, VII
HO
OH
DCC
DMAP
O
O
O
X
O
X
O
O
O
O
Y
Y
H2n+1CnO
OCnH2n+1
VIII, IX
X = H, Y = Cl (II); X = Y = Cl (III); n = 9 (Vа), 10 (Vb), 12 (Vc), 16 (Vd); X = H, Y = Cl, n = 9 (VIа, VIIIа) 10 (VIb,
VIIIb), 12 (VIc, VIIIc); X = Y = Cl, n = 9 (VIIа, IXа), 10 (VIIb, IXb), 12 (VIIc, IXc), 16 (VIId, IXd).
by treating the corresponding acids with thionyl
chloride [10] (Scheme 1).
scopy method (Table 1); for comparison, charac-
teristics of unsubstituted 4-(4-n-alkoxybenzoyl-oxy)
benzoic acids VII'a–VII'd are also provided [8].
The structures of new chlorine-containing acids
VIa–VIc and VIIa–VIId, and the target products
VIIIa–VIIIc and IXa–IXd were established by H
NMR spectroscopy.
The presented data indicate the reduction of the
transition point to isotropic liquid as follows: VII'a–
VII'd > VIa–VIc > VIIa–VIId.
1
Transition points and mesomorphism type of 4-(4-
n-alkoxybenzoyloxy)benzoic acids VIa–VIc and
VIIa–VIId were determined by polarization micro-
The introduction of the chlorine atom into the
molecule led to the absence of polymorphism in both
mono- and dichloro-substituted acids whereas their
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 3 2015

BANANA-SHAPED LIQUID CRYSTALS
579
Table 1. Transition points of 4-(4-n-alkoxybenzoyloxy)-3-chlorobenzoic acids VIa–VIc, 4-(4-n-alkoxybenzoyloxy)-3,5-
dichlorobenzoic acids VIIa–VIId, and their unsubstituted analogs VII'a–VII'da
Transition point, °С
Comp. no.
n
X
Y
Cr
•
Sm
−
−
−
−
−
−
−
•
N
•
I
•
•
•
•
•
•
•
•
•
•
•
VIa
9
Cl
Cl
Cl
Cl
Cl
Cl
Cl
H
H
H
95.4
108.2
95.4
148
177
VIb
10
12
9
•
•
173
VIc
H
•
•
157.2
VIIa
VIIb
VIIc
VIId
VII'a
VII'b
VII'c
VII'd
Cl
Cl
Cl
Cl
H
•
−
10
12
16
9
•
120
(•
(•
(•
•
112)
110)
•
117
•
92.3
125
85.6)
•
140
204
205
218
10
12
16
H
H
•
133
•
•
H
H
•
120
•
182
•
213
b
Н
Н
•
115
•
>200
•
a
Here and further: Cr is solid crystal, N is nematic phase, Sm is smectic phase, I is isotropic liquid, (•) is monotropic mesophase, n is the
number of the carbon atoms in the terminal alkoxygroup. b Measurement of the transition point to isotropic liquid did not succeed.
unsubstituted analogs VII’a–VII’d formed nematic
and smectic phases. Comparison of mesomorphism of
mono- and dichloro-substituted acids showed that 4-(4-
n-alkoxybenzoyloxy)-3-chlorobenzoic acids VIa–VIc
exhibited the enantiotropic nematic mesophase while
for their dichloro-analogs VIIa–VIId the monotropic
nematic phase was observed. Compounds VIIa
containing nine carbon atoms in the terminal chain did
not possess mesogenic capability that was apparently
caused by distortion of the geometric anisotropy of the
molecule (insufficient length of the terminal fragment).
scattering (see the figure). According to the data of
X-ray phase analysis, the molecules in the blocks are
oriented by their long axes along the length of the
crystallographic cell.
The next homolog VIIIb displayed insignificant
reduction of the transition points values, and the phase
B1 became monotropic. Further elongation of the
terminal chain led to the appearance of the modifica-
tion of banana-shaped mesophase B2 in bis-2,7-[4-(4-
n-dodecyloxybenzoyloxy)-3-chlorobenzoyloxy]naph-
thalene VIIIc. The data of small angle X-ray scattering
of the sample of the compound oriented in magnetic
field confirmed this modification formation. It was
found that compound VIIIc formed mesophase with
the layer thickness of 34.7 Å, and the molecules in the
layer were tilted with respect to the plane of the layer
by an angle of approximately 45° that corresponded to
the bilayer banana-shaped smectic phase.
Mesomorphic characteristics of bis-2,7-[4-(4-n-
alkoxybenzoyloxy)-3-chlorobenzoyloxy]naphthalenes
VIIIa–VIIIc and bis-2,7-[4-(4-n-alkoxybenzoyloxy)-
3,5-dichlorobenzoyloxy]naphthalenes IXa–IXd are
given in Table 2; for comparison, characteristics of
their unsubstituted analogs IX'a–IX'd are also
provided [3].
The data presented in the Table 3 demonstrate that
all banana-shaped compounds containing one chlorine
atom at the aromatic ring are mesomorphic. Mono-
chloro-substituted 2,7-dihydroxynaphthalene diester
with terminal nonyloxy group VIIIa formed enantio-
tropic nematic and biaxial smectic modification B1.
The mesophase type and packing of the molecules
were determined from the data of small angle X-ray
Introduction of the second chlorine atom into the
aromatic ring of the side fragments led to the loss of
mesogenic capability in compounds IXa–IXd (Table 2).
At the same time melting points of bis-2,7-[4-(4-n-
alkoxybenzoyloxy)-3,5-dichlorobenzoyloxy]naphthalenes
IXa–IXd are significantly reduced compared to bis-
2,7-[4-(4-n-alkoxybenzoyloxy)-3-chlorobenzoyloxy]-
naphthalenes VIIIa–VIIIc, and the dichlorinated
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 3 2015

580
DERKACH et al.
Table 2. Transition points of chlorine-containing (VIIIa–VIIIc, IXa–IXd) and unsubstituted 2,7-dihydroxynaphthalene
esters (IX'a–IX'd)a
Transition point, °С
Comp. no.
n
X
Y
Cr
B1
B2
N
I
VIIIa
VIIIb
VIIIc
IXa
9
Cl
Cl
Cl
Cl
Cl
Cl
Cl
H
H
H
•
•
•
•
•
•
•
•
•
•
•
111.2
104.8
76.2
(32.7)
(21)
•
116.3
−
−
•
•
•
116.6
112.9
80.4
68
•
10
12
9
•
(104.9)
•
•
•
•
•
•
•
•
•
•
H
−
−
−
−
−
•
−
−
−
−
−
−
−
•
Cl
Cl
Cl
Cl
H
−
−
−
−
−
−
−
•
IXb
10
12
16
9
68
IXc
(36.2)
(40.2)
143
75
IXd
78.4
175
168
170
173
IX'a
IX'b
IX'c
IX'd
10
12
16
H
H
131
•
H
H
122
−
–
Н
Н
122
–
a See Table 1.
analogs IXa–IXd are capable of supercooling and
vitrification at room temperature.
oxy]naphthalene VIIIc phase B2 formation was
observed under ordinary conditions and there was no
necessity to place the sample in an electric field.
In summary, bis-2,7-[4-(4-n-alkoxybenzoyloxy)-3-
chlorobenzoyloxy]naphthalenes VIIIa and VIIIb are
characterized by the appearance of an additional
nematic phase compared to the unsubstituted analogs
IX'a and IX'b which formed only mesophase B1. For
the formation of phase B2 both the monochloro-
substituted and unsubstituted 2,7-dihydroxynaph-
thalene diesters should contain no less than 12 carbon
atoms in the terminal alkoxy group. In the case of bis-
2,7-[4-(4-n-dodecyloxybenzoyloxy)-3-chlorobenzoyl-
EXPERIMENTAL
1H NMR spectra of the solutions in CDCl3, DMSO-
d6, and CD3OD were recorded on a Varian VXR-300
(300 MHz) and Bruker AVANCE DRX 500 (500 MHz)
spectrometers, internal reference TMS. The reaction
progress was monitored by TLC using Sorbifol AF-V-
UV plates, eluting with acetone–hexane mixture (2 : 5)
and developing with iodine vapor or UV light.
Transition points were determined by polarization
microscopy method on a POLAM P-312 microscope.
The X-ray phase analysis was done on a Bruker
GAADS system. Dielectric response was measured
with the use of analyzer of terminating impedance with
the cell of 5 mm thickness and gold electrodes.
47 Å
3-Chloro-4-hydroxybenzoic acid (II). 2 mL of
33% hydrogen peroxide was added to a suspension of
3.5 g (0.025 mol) of 4-hydroxybenzoic acid I in 10 mL
of hydrochloric acid. The reaction proceeded almost
instantly with self-heating of the reaction mixture up to
70°C. After cooling to room temperature, 70 mL of
distilled water was added. The precipitate was filtered
off, washed with water to pH 7, and recrystallized
34.8 Å
Packing of the molecules of compound VIIIa in mesophase B1.
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BANANA-SHAPED LIQUID CRYSTALS
581
from hot water. Yield 2.9 g (67.44%), white crystals,
mp 174°С. 1Н NMR spectrum, δ, ppm: 7.05 d (1Н, Н5,
3J 7.53 Hz), 7.67–7.93 m (2Н, Н2,6), 11.07 br.s (1Н,
ОН), 12.79 br.s (1Н, СООН).
ppm: 0.86 t (3Н, СН3, J 6.9 Hz), 1.15–1.51 m (16 Н,
СН2), 1.64–1.86 m (2Н, СН2), 4.09 t ( 2Н, OCH2, J
6.2 Hz), 7.15 d (2Н, ArOAlk, J 8.7 Hz), 7.59 d (1Н,
ArCl, J 8.4 Hz), 7.98–8.00 d.d (1Н, ArCl, J 8.4,
1.3 Hz), 8.06–8.26 m (3Н, ArOAlk, ArCl). Found, %:
C 67.81; H 7.12; Cl 7.78%. C26H33ClO5. Calculated,
%: C 67.75; H 7.17; Cl 7.71.
3,5-Dichloro-4-hydroxybenzoic acid (III). 10 mL
of 33% hydrogen peroxide was added to a suspension
of 3.5 g (0.025 mol) of 4-hydroxybenzoic acid I in
10 mL of hydrochloric acid and 20 mL of water. The
formed white precipitate was filtered off, washed with
hot water, and recrystallized from ethanol. Yield
4-(4-n-Hexadecyloxybenzoyloxy)-3-chlorobenzoic
acid (VId). Yield 1.73 g (48%), white amorphous
1
powder. Н NMR spectrum (DMSO-d6, 300 MHz), δ,
1
3.19 g (63.5%), white crystals, mp 265°С. Н NMR
ppm: 0.85 t (3Н, СН3, J 6.9 Hz), 1.15–1.49 m (СН2,
26Н), 1.65–1.82 m (2Н, СН2), 4.09 t ( 2Н, OCH2, J
6.9 Hz), 7.14 d (2Н, ArOAlk, J 8.7 Hz), 7.59 d (1Н,
ArCl, J 8.7 Hz), 7.98–8.00 d.d (1Н, ArCl, J 8.4,
1.6 Hz), 8.07–8.20 m (3Н, ArOAlk, ArCl). Found, %:
C 69.79; H 7.8; Cl 6.95%. C30H41ClO5. Calculated, %:
C 69.70; H 7.94; Cl 6.87.
spectrum, δ, ppm: 7.84 s (2Н, Н2,6). Found, %: C
40.64; H 1.87; Cl 34.34. C7H4Cl2O2. Calculated, %: C
40.58; H 1.93; Cl 34.30.
4-(4-n-Alkoxybenzoyloxy)-3-chlorobenzoic acids
(VIa–VId) (general procedure). To a suspension of
6 mL of 3-chloro-4-hydroxybenzoic acid II in 25 mL
of anhydrous pyridine was added dropwise 6 mmol of
the corresponding 4-n-alkoxybenzoic acid chloride V.
The reaction mixture was stirred at room temperature
for 30 h then poured into ice water and acidified to pH
3. The formed white precipitate was filtered off,
washed with water to pH 7, and then suspended in
ethanol (100 mL) at room temperature followed by
repeated filtration and drying.
4-(4-n-Alkoxybenzoyloxy)-3,5-dichlorobenzoic
acids (VIIa–VIId) (general procedure). To
a
suspension of 4 mmol of 3,5-dichloro-4-hydroxy-
benzoic acid III in 25 mL of anhydrous pyridine was
added dropwise 4 mmol of the corresponding 4-n-
alkoxybenzoic acid chloride V. The reaction mixture
was stirred at room temperature for 30 h, and then
poured into ice. Four hours later the precipitate formed
was filtered off, washed with cold ethanol (50 mL),
and dried. The prepared compounds were white powders.
4-(4-n-Nonyloxybenzoyloxy)-3-chlorobenzoic acid
(VIa). Yield 1.5 g (62.1%), white amorphous powder.
1Н NMR spectrum (DMSO-d6, 300 MHz), δ, ppm:
0.89 t (3Н, СН3, J 6.9 Hz), 1.22–1.55 m (10Н, СН2),
1.77–1.91 m (2Н, СН2), 1.66–1.81 m (2Н, СН2), 4.10 t
(2Н, OCH2 J 5.7 Hz), 7.15 d (2Н, ArOAlk, J 8.1 Hz),
7.6 d (1Н, ArCl, J 8.1 Hz), 8.00–7.98 d.d (1Н, ArCl, J
8.1, 0.8 Hz), 8.09–8.12 m (3Н, ArOAlk, ArCl). Found,
%: C 65.99; H 6.38; Cl 8.42. C23H27ClO5. Calculated,
%: C 65.95; H 6.45; Cl 8.48.
4-(4-n-Nonyloxybenzoyloxy)-3,5-dichlorobenzoic
1
acid (VIIa). Yield 0.9 g (51.5%). Н NMR spectrum
(DMSO-d6, 300 MHz), δ, ppm: 0.86 t (3Н, СН3, J
6.5 Hz), 1.16–1.52 m (СН2, 12Н), 1.68–1.85 m (2Н,
СН2), 4.11 t (2Н, OCH2, J 6.5 Hz), 7.17 d (2Н,
ArOAlk, J 7.8 Hz), 8.05–8.26 m (4Н, ArCl2, ArOAlk).
Found, %: C 60.85; H 5.79; Cl 15.76. C23H26Cl2O5.
Calculated, %: C 60.93; H 5.74; Cl 15.67.
4-(4-n-Decyloxybenzoyloxy)-3-chlorobenzoic acid
(VIb). Yield 2.3 g (59%), white amorphous powder.
1Н NMR spectrum (DMSO-d6, 500 MHz), δ, ppm:
0.86 t (3Н, СН3, J 5.7 Hz), 1.15–1.52 m (16Н, СН2),
1.68–1.85 m (2Н, СН2), 4.10 t (2Н, OCH2, J 5.7 Hz),
7.14 d (2Н, ArOAlk, J 8.1 Hz), 7.60 d (1Н, ArCl, J
8.0 Hz), 7.99–8.00 d.d (1Н, ArCl, J 8.04, 0.78 Hz),
8.05–8.2 m (3Н, ArOAlk, ArCl), 13.42 br.s (1Н,
СООН). Found, %: C 66.67; H 6.79; Cl 8.29.
C24H29ClO5. Calculated, %: C 66.59; H 6.71; Cl 8.21.
4-(4-n-Decyloxybenzoyloxy)-3,5-dichlorobenzoic
acid (VIIb). Yield 5.56 g (79.5%). 1Н NMR spectrum
(CD3OD, 300 MHz), δ, ppm: 0.90 t (3Н, СН3, J
6.4 Hz), 1.26–1.52 m (СН2, 14Н), 1.70–1.95 m (2Н,
СН2), 4.11 t (2Н, OCH2, J 6.4 Hz), 7.10 d (2Н,
ArOAlk, J 8.7 Hz), 8.08–8.19 m (4Н, ArCl2, ArOAlk).
Found, %: C 61.77; H 5.92; Cl 15.29. C24H28Cl2O5.
Calculated, %: C 61.67; H 6.00; Cl 15.20.
4-(4-n-Dodecyloxybenzoyloxy)-3,5-dichlorobenzoic
1
acid (VIIc). Yield 6.0 g (71.3%). Н NMR spectrum
4-(4-n-Dodecyloxybenzoyloxy)-3-chlorobenzoic
acid (VIc). Yield 1.9 g (59%), white amorphous
powder. Н NMR spectrum (DMSO-d6, 300 MHz), δ,
(CD3OD, 300 MHz), δ, ppm: 0.88 t (3Н, СН3, J
6.9 Hz), 1.52–1.18 m (СН2, 18Н), 1.75–1.90 m (2Н,
СН2), 4.10 t (2Н, OCH2, J 6.9 Hz), 7.09 d (2Н,
1
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DERKACH et al.
ArOAlk, J 8.7 Hz), 8.06–8.23 m (4Н, ArCl2, ArOAlk).
Found, %: C 63.11; H 6.38; Cl 14.41. C26H32Cl2O5.
Calculated, %: C 63.03; H 6.47; Cl 14.34.
Cl 7.26%. C58H62Cl2O10. Calculated, %: C 70.37; H
6.27; Cl 7.18.
2,7-Bis[4-(4-n-dodecyloxybenzoyloxy)-3-chloro-
benzoyloxy]naphthalene (VIIIc). Yield 0.6 g (57.4%).
1Н NMR spectrum (CDCl3, 300 MHz), δ, ppm: 0.89 t
(6Н, СН3, J 6.9 Hz), 1.15–1.70 m (36Н, СН2), 1.70–
1.95 m (4Н, СН2СН2О), 4.06 t (4Н, ОСН2, J 6.5 Hz),
7.00 d (4Н, АrOAlk, J 8.7 Hz), 7.36–7.39 d.d (2Н,
naphthalene, J 8.9, 2.2 Hz), 7.48 d (2Н, АrCl, J
8.7 Hz), 7.70 s (2Н, naphthalene), 7.97 d (2Н, naphtha-
lene, J 8.7 Hz), 8.15–8.32 m (6Н, АrOAlk, АrСl), 8.39
s (2Н, АrCl). Found, %: C 71.29; H 6.63; Cl 6.89.
C62H70Cl2O10. Calculated, %: C 71.20; H 6.70; Cl 6.80.
4-(4-n-Hexadecyloxybenzoyloxy)-3,5-dichlorobenzoic
1
acid (VIId). Yield 1.6 g (42.0%). Н NMR spectrum
(CDCl3, 300 MHz), δ, ppm: 0.88 t (3Н, СН3, J 6.9 Hz),
1.16–1.52 m (26Н, СН2), 1.76–1.90 m (2Н, СН2), 4.10
t (2Н, OCH2, J 6.9 Hz), 7.09 d (2Н, ArOAlk, J 8.7
Hz), 8.04–8.26 m (4Н, ArCl2, ArOAlk). Found, %: C
65.45; H 7.35; Cl 12.80. C30H40Cl2O5. Calculated, %:
C 65.34; H 7.26; Cl 12.89.
2,7-Bis[4-(4-n-alkoxybenzoyloxy)-3-chlorobenz-
oyloxy]naphthalenes (VIIIa–VIIIc) (general preoce-
dure). A suspension of 1.5 mmol of the corresponding
4-(4-n-alkoxybenzoyloxy)-3-chlorobenzoic acid VIa–
VIc, 0.75 mmol of 2,7-dihydroxynaphthalene, and
0.15 mmol of 4-(dimethylamino)pyridine in 20 mL of
anhydrous chloroform was stirred for 10 min at room
temperature. Then 1.5 mmol of N,N'-dicyclohexyl-
carbodiimide was added. The reaction mixture was
stirred for 20 h at room temperature. The precipitate
formed was filtered off and washed with chloroform
(3 × 20 mL). The organic layers were combined,
washed, and evaporated. The residue was triturated
with ethanol, and the crystalline solid obtained was
recrystallized from a mixture benzene–ethanol. The
prepared compounds were white powders.
2,7-Bis[4-(4-n-alkoxybenzoyloxy)-3,5-dichlorobenz-
oyloxy]naphthalenes IXa–IXd were prepared similarly.
2,7-Bis[4-(4-n-nonyloxybenzoyloxy)-3,5-dichloro-
benzoyloxy]naphthalene (IXa). Yield 0.2 g (38.8%).
1Н NMR spectrum (CDCl3, 300 MHz), δ, ppm: 0.89 t
(6Н, СН3 J 6.5 Hz), 1.20–1.66 m (24Н, СН2), 1.75–
1.90 m (4Н, СН2СН2О), 4.07 t (4Н, ОСН2, J 6.5 Hz),
7.02 d (4Н, АrOAlk, J 8.7 Hz), 7.36–7.39 d.d (2Н,
naphthalene, J 8.7, 2.2 Hz), 7.71 s (2Н, naphthalene),
7.97 d (2Н, naphthalene, J 8.7 Hz), 8.15–8.36 m (6Н,
АrOAlk, АrCl2). Found, %: C 65.32; H 5.36; Cl 13.86.
C56H56Cl4O10. Calculated, %: C 65.24; H 5.44; Cl 13.79.
2,7-Bis[4-(4-n-decyloxybenzoyloxy)-3,5-dichloro-
benzoyloxy]naphthalene (IXb). Yield 3.2 g (61.0%).
1Н NMR spectrum (CDCl3, 300 MHz), δ, ppm: 0.89 t
(6Н, СН3, J 6.6 Hz), 1.20–1.70 m (28Н, СН2), 1.75–
1.90 m (4Н, СН2СН2О), 4.07 t (4Н, ОСН2, J 6.5 Hz),
7.02 d (4Н, АrOAlk, J 8.7 Hz), 7.36–7.39 d.d (2Н,
naphthalene, J 8.7, 2.2 Hz), 7.71 s (2Н, naphthalene),
7.97 d (2Н, naphthalene, J 9.0 Hz), 8.15–8.35 m (6Н,
АrOAlk, АrCl2). Found, %: C 65.70; H 5.77; Cl 13.49.
C58H60Cl4O10. Calculated, %: C 65.78; H 5.67; Cl 13.42.
2,7-Bis[4-(4-n-nonyloxybenzoyloxy)-3-chlorobenz-
1
oyloxy]naphthalene (VIIIa). Yield 0.4 g (55.6%). Н
NMR spectrum (CDCl3, 300 MHz), δ, ppm: 0.89 t
(6Н, СН3, J 6.9 Hz), 1.23–1.59 m (24Н, СН2), 1.77–
1.89 m (4Н, СН2СН2О), 4.06 t (4Н, ОСН2, J 6.5 Hz),
7.00 d (4Н, АrOAlk, J 9.0 Hz), 7.37–7.4 d.d (2Н,
naphthalene, J 9.0, 2.2 Hz), 7.49 d (2Н, АrCl, J
8.7 Hz), 7.71 s (2Н, naphthalene), 7.95 d (2Н,
naphthalene, J 8.7 Hz), 8.14–8.30 m (4Н, АrOAlk,
АrСl), 8.40 s (2Н, АrCl). Found, %: C 69.99; H 6.13;
Cl 7.48. C56H58Cl2O10. Calculated, %: C 69.93; H 6.04;
Cl 7.39.
2,7-Bis[4-(4-n-dodecyloxybenzoyloxy)-3,5-di-
chlorobenzoyloxy]naphthalene (IXc). Yield 0.36 g
1
(42.0%). Н NMR spectrum (CDCl3, 300 MHz), δ,
ppm: 0.89 t (6Н, СН3, J 6.5 Hz), 1.20–1.65 m (36Н,
СН2), 1.70–2.00 m (4Н, СН2СН2О), 4.06 t (4Н, ОСН2,
J 6.5 Hz), 7.02 d (4Н, АrOAlk, J 8.4 Hz), 7.37–7.39
d.d (2Н, naphthalene, J 8.4, 1.2 Hz), 7.71 s (2Н,
naphthalene), 7.97 d (2Н, naphthalene, J 8.7 Hz),
8.15–8.38 m (6Н, АrOAlk, АrCl2). Found, %: C 66.70;
H 6.18; Cl 12.68. C62H68Cl4O10. Calculated, %: C
66.79; H 6.10; Cl 12.75.
2,7-Bis[4-(4-n-decyloxybenzoyloxy)-3-chlorobenz-
oyloxy]naphthalene (VIIIb). Yield 0.68 g (68.2%).
1Н NMR spectrum (CDCl3, 300 MHz), δ, ppm: 0.91 t
(6Н, СН3, J 6.4 Hz), 1.19–1.55 m (28Н, СН2), 1.78–
1.89 m (4Н, СН2СН2О), 4.07 t (4Н, ОСН2, J 6.4 Hz),
7.01 d (4Н, АrOAlk, J 8.7 Hz), 7.38–7.40 d.d (2Н,
naphthalene, J 7.9, 2.2 Hz), 7.49 d (2Н, АrCl, J
8.7 Hz), 7.71 s (2Н, naphthalene), 7.96 d (2Н,
naphthalene, J 8.7 Hz), 8.13–8.29 m (6Н, АrOAlk,
АrСl), 8.39 s (2Н, АrCl). Found, %: C 70.48; H 6.33;
2,7-Bis[4-(4-n-hexadecyloxybenzoyloxy)-3,5-di-
chlorobenzoyloxy]naphthalene (IXd). Yield 1.8 g
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 3 2015

BANANA-SHAPED LIQUID CRYSTALS
583
(48.0%). 1Н NMR spectrum (CDCl3, 300 MHz), δ, ppm:
0.91 t (6Н, СН3, J 6.9 Hz), 1.18–1.65 m (52Н, СН2),
1.78–1.93 m (4Н, СН2СН2О), 4.09 t (4Н, ОСН2, J
6.5 Hz), 7.04 d (4Н, АrOAlk, J 8.3 Hz), 7.39–7.41 d.d
(2Н, naphthalene, J 8.3, 1.2 Hz), 7.73 s (2Н, naphtha-
lene), 7.99 d (2Н, naphthalene, J 8.8 Hz), 8.15–8.38 m
(6Н, АrOAlk, АrCl2). Found, %: C 68.60; H 6.78; Cl
11.68. C70H84Cl4O10. Calculated, %: C 68.52; H 6.85;
Cl 11.58.
2000, vol. 27, no. 12, p. 1613. DOI: 10.1080/
026782900750037176.
4. Amaranatha, R.R., and Sadashiva, B.K., J. Mater.
Chem., 2004, vol. 14, p. 1936. DOI: 10.1039/b313295a.
5. Jákli, A., Krüerke, D., and Nair, G.G., Phys. Rev. (E),
2003, vol. 67, p. 051702. DOI: 10.1103/
PhysRevE.67.051702.
6. Eremin, A., Diele, C., Pelzl, G., and Weissflog, W.,
Phys. Rev. (E), 2003, vol. 67, p. 020702. DOI: 10.1103/
PhysRevE.67. 020702.
7. Etxebarria, Je. and Ros, M.B., J. Mater. Chem., 2008,
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 85 No. 3 2015