chapter vi salicylaldimine-based banana-shaped liquid...
TRANSCRIPT
VI. 1. Scope of the work
In a way to realize stable banana-shaped compounds several mesogenic
segments such as tolane, biphenyls, and phenylbenzoates have been employed. As
expected these bent cores show good thermal stability with a remarkable
mesomorphic behavior. Synthesis of bent-core compounds with different chemical
architecture is of topical interest for understanding the relationship between the
chemical structure and mesophase behaviour. Most of the BC compounds
exhibiting mesophases that have been reported in the literature are symmetrical
about the central unit and are derived from 1, 3-dihydroxybenzene [1-6]. 2, 7-
dihydroxynaphthalene [7, 8] and benzene-1, 3-dicarboxylic acid [9]. Introduction
of lateral substituents on the arms of bent core molecules for modifying the
mesomorphic properties has been carried out [10-15] on a number of different
systems. With respect to the bent-core molecular architectures, the traditional
banana-shaped liquid crystals were generally formed by two bent-substituted rigid
arms connected to a central cyclic ring (through polar or nonpolar functional
groups) with a suitable bent angle and linking, where appropriate lengths of
flexible chains were attached [17]. A variety of interesting phenomena, especially
related to chirality and polarity, has been found in these materials, and the topic
has been object of several reviews [17-20]. For example salicylaldimine core
based classical ferroelectric liquid crystals are known to be stable [16b, 16c](Fig.
VI.1.a)
NO
O HCnH2n+1
MORA-n Series
NO
O HCnH2n+1
MBRA-n Series
NO
O HCnH2n+1OC
OH2C
(a)
(b)
Figure. VI. 1. (a) Molecular structure of salicylaldimine-based FLCs, (b) salicyaldimine-
based achiral side-chain polymer exhibiting antiferroelectric switching characteristics.
Alternatively, stable bent cores can be designed by incorporating
salicylaldimine mesogenic segment which has close chemical resemblance to
the Schiffs base moiety and is known to be stable due to the presence of
intramolecular hydrogen bonding between H-atom of hydroxyl group and N-
atom of bonding between H-atom of hydroxyl group and N-atom of imine
functionality [16a]. Salicylaldimine core has played a vital role in the first
discovery of Soto-Bustamante / Blinov anticlinic bilayer antiferroelectrics
formed by achiral side chain polymer in which it is a pendant segment [16d].
The Soto-Bustamante / Blinov results reinforce the concept that such structural
features may prove interesting when incorporated into bent core molecules.
Owing to these attractive features of salicylaldimine mesogenic segment, we
intended to explore this modification to the classical banana shaped molecule.
VI. 2. Molecular design
In the present work we propose to study a new series of symmetric banana
shaped liquid crystals consisting of Isophthalic acid bis-(4-amino-phenyl) ester
core connected to 4-Decyloxy-2-hydroxy-benzaldehyde via ester linkage. In the
following sectiion we present the synthesis and characterisation of the compounds
in detail. A general molecular structure of the target banana molecule is shown
below.
OO
O O
N
N
RO OH
HO ORR=CnH2n+1
n = 4, 5, 6, 7, 8, 9, 10, 11, 16
VI. 3. Synthesis and molecular structural characterization
The intermediate (1b) were synthesized in two steps. Firstly,the
esterification of isophthalic acid with 4-nitro phenol, dicyclohexylcarbodiimide,
N, N-dimethylaminopyridine and tetrahydrofuran as the solvent to obtain
compound (1a). Reduction of this compound by 10% Pd/C using tetrahydrofuran
as the solvent gives the intermediate (1b). Both intermediates were performed
according to literature procedures [21]. As a representative case the 1H NMR
spectra of the banana molecule is shown in Fig.VI. 2.
Figure. VI. 2. 1H NMR (200MHz) spectra of D-10 in CDCl3
OO
HO OH
OO
O O
O2N NO2
OO
O O
H2N NH2
HO CHO
OH
RO CHO
OH
OO
O O
N
N
RO OH
HO OR
(i)
(ii) (iii)
R=CnH2n+1
n = 4, 5, 6, 7, 8, 9, 10, 11, 16
(iv)
Reagents and condition; (i) 4-nitrophenol, DCC, DMAP, tetrahtdrofuran; (ii) 10%
Pd/C, tetrahydrofuran; (iii) 1-bromoalkane, KHCO3, MEK; (iv) absol.ethanol,
gla.CH3COOH.
(1b)(2a)
(1a)
series D-n
VI. 4. Results and discussion
The liquid crystalline behaviour of the compounds was preliminarily
investigated with the help of POM and DSC. Transition temperatures and
associated enthalpies obtained from DSC thermograms are shown in Table. 1. A
study of large number of compounds has indicated that the occurrence of B1 and
B2 phases is dependent on terminal chain length. However the nature of the
mesophase has varied form lower to higher homologues. The transition
temperatures are higher for salicylaldimines due to the presence of intramolecular
H-bonding between H-atom of hydroxyl group and N-atom of imine functionality.
All the compounds were found to be mesomorphic and the obtained enthalpy
values of about 19 to 24 J g-1
for mesophase to isotropic phase transition are in
agreement with the values reported for banana-shaped compounds. As a
representative case the DSC scans obtained at a rate of 10oC/min for the D-10
sample is shown in Fig. I. 3.
Fig. VI. 3. Differential scanning calorimetric thermogram of compound D-10 obtained at
a rate of 10oC min
-1: (a) heating cycle (b) cooling cycle.
Table 1. Transition temperatures (oC) and enthalpies of transitions (KJ molˉ
1) for the compounds
Compound n Cr Heating
Cooling
B1 Heating
Cooling
B2 Heating
Cooling
D-4 4 • 164.0[33.9]
179.3[32.6]
• 221.4[21.9]
224.8[22.4]
- -
D-5 5 • 157.2[39.0]
162.3[36.8]
• 218.6[20.5]
217.6[21.0]
- -
D-6 6 • 141.5[29.0]
153.9[30.1]
• 220.3[19.2]
219.0[18.1]
- -
D-7 7 • 149.2[28.8]
158.2[32.0]
• 214.8[23.7]
215.0[23.1]
- -
D-8 8 • 120.1[31.0]
127.3[30.9]
• 213.8[19.2]
214.5[18.5]
- -
D-9 9 • 118.4[27.5]
125.8[29.0]
• 213.9[15.7]
213.1[17.6]
- -
D-10 10 • 116.5[33.6]
123.7[30.4]
- - • 209.5[22.9]
210.0[23.4]
D-11 11 • 113.4[28.7]
121..0[29.]
- • 211.7[21.8]
209.3[21.5]
D-16* 16
*This compound exhibit Cr-Cr transition.
Cr-crystal; B1-banana phase; B2-banana phase; I-isotropic.
All the compounds except D-16 exhibit enantiotropic liquid crystalline phases, its
type depending on the length of the terminal alkoxy chain. The longer
homolouges D-10 and D-11 exhibit B2 mesophase, but D-16 does not show any
phase. It exhibit only crystal to crystal transition. An example of the B2 textures
observed for D-10 is given in plate VI. 4. 1. The bent cores D-6 and D-7 show an
identical mesophase over 219oC and 215
oC temperature range respectively.
plate VI. 4. 1 Photomicrograph of the texture observed on cooling from the isotropic state for D-
10 at 210oC.
plate VI. 4. 2. Photomicrograph of the texture observed on cooling from the isotropic state for D-8
at 214. 5oC.
For the short tailed members, the B1 phase was observed on cooling
from the isotropic state by the formation of small battonets. PlateVI. 4.2 show the
texture seen under the polarized microscope for the compound D-8 at 214.5oC.
The texural patterns matches with textures obtained for the B1 phase of the lower
homologues of the parent series of banana compounds.
VI. 5. Conclusion
All nine salicylaldimine-based compounds that have been synthesized
exhibit stable liquid crystalline phases. As in most banana–shaped liquid crystals,
a phenyl or biphenyl central part promotes the formation of B-phases. In our
studies B1 phase was observed for the lower homologues and the higher
homologues exhibit B2 phase.
VI. 6. Experimental
In this section the detailed synthetic procedures and the molecular
structural characterization data has been presented for the intermediates and target
compounds
General procedure for the synthesis of Isophthalic acid bis (4-nitro-phenyl)
ester (1)
Isophthalic acid (1g, 0. 006 mol) and 4-nitro phenol (1. 46g, 0. 012 mol)
were dissolved in dry CH2Cl2 (30 ml). To this DCC (2. 68g, 0. 013 mol) and a
catalytic amount of DMAP were added and the mixture was stirred at room
temperature for about 3 hours. The precipitated dicyclohexylurea was filtered off
and washed thoroughly with CH2Cl2. The combined filtrate was washed with
water and dried over Na2SO4. The crude product was purified by column
chromatography using silica gel (100-200 mesh) and 10% EtOAc-hexane elution
afforded the product.
Rf = 0.4 in 30% EtOAc-Hexane; Yield=42%; A white solid; IR (KBr pellet): 1985,
1769, 1635, 1192, 1025, 875 cm-1
; ¹H NMR (CDCl3, 200MHz) δ: 9.03 (s, 1H, Ar),
8.35 (d, J=8.6 Hz, 2H, Ar), 8.27 (d, J=8.6 Hz, 2H, Ar), 7.59 (s, 1H, Ar), 7.40 (d,
J=8.6 Hz, 2H, Ar)
General procedure for the synthesis of Isophthalic acid bis - (4-amino-phenyl)
ester
Isophthalic acid bis (4-nitro-phenyl) ester (1g, 1equiv. ) was dissolved in
dry THF and 10% Pd-C (10% weight of the nitro compound) was added. The
reaction mixture was degassed and stirred under H2 gas (1 atmospheric pressure)
for 4 h at rt. The reaction mixture was filtered over celite bed, concentrated and
the solid obtained was recrystallized from hexanes to afford a brown solid.
Rf = 0.23 in 50% EtOAc-Hexane; Yield=35%; A brown solid; IR (KBr pellet):
1975, 1769, 1625, 1192, 1025, 875 cm-1
; ¹H NMR (CDCl3,200MHz) δ: 9.02 (s,
1H, Ar), 8.38 (d, J=8.6 Hz, 2H, Ar), 6.92 (d, 2H, Ar), 6.51 (d, J=8.6 Hz, 2H, Ar).
General procedure for the synthesis of 2-hydroxy-4-n-alkoxybenzaldehydes
A mixture of 2,4-dihydroxybenzaldehyde (1equiv.), 1-bromoalkane (0. equiv.
), KHCO3 (dry) (3.0 equiv. ) and dry acetone (~20 ml) was refluxed under N2
atmosphere for 12 h. Acetone was evaporated off and to the residue about 200ml of
water was added. A dark brown coloured suspension thus obtained was extracted with
CH2Cl2 (20 mlX2). The combined organic extracts were washed with brine and dried
over Na2SO4. Evaporation of solvent furnished a brown coloured mass, which was
purified by column chromatography using silica gel (100-200-mesh). Elution with a
mixture of 10% EtOAc-hexane furnished pure product.
2-hydroxy-4-n-pentyloxybenzaldehyde
Rf = 0.41 in 10% EtOAc-hexane; Yield: 41.2%; A pale yellow liquid; IR (Neat):
2960, 2929, 1629, 1574, 1508cm-1
; 1H NMR (CDCl3,200MHz)δ: 11.48 (s, 1H,
1XOH), 9.7 (s, 1H, 1XCHO), 7.41 (d, J=8.6 Hz, 1H, Ar), 6.52 (d, J=8.6 Hz, 1H,
Ar), 6.41 (d, J=2.3 Hz, 1H, Ar), 4.01 (t, J=6.5 Hz, 2H, 1XOCH2), 1.83-1.25 (m, 6H,
3XCH2), 0.99 (t, J=7.1, 3H, 1XCH3).
2-hydroxy-4-n-hexyloxybenzaldehyde
Rf = 0.41 in 10% EtOAc-hexane; Yield: 41.6%; A pale yellow liquid; IR (Neat):
2930, 2929, 1654, 1574, 1508cm-1
; 1H NMR (CDCl3,200MHz)δ: 11.48 (s, 1H,
1XOH), 9.7 (s, 1H, 1XCHO), 7.41 (d, J=8.6 Hz, 1H, Ar), 6.52 (d, J=8.6 Hz, 1H,
Ar), 6.41 (d, J=2.3 Hz, 1H, Ar), 4.01 (t, J=6.5 Hz, 2H, 1XOCH2), 1.83-1.25 (m,
8H, 4XCH2), 0.99 (t, J=7.1, 3H, 1XCH3).
2-hydroxy-4-n-heptyloxybenzaldehyde
Rf = 0.43 in 10% EtOAc-hexane; Yield: 47.3%; A pale yellow liquid; IR (Neat):
2960, 2855, 1629, 1575, 1507cm-1
; 1H NMR (CDCl3,200MHz) δ: 11.47 (s, 1H,
1XOH), 9.7 (s, 1H, 1XCHO), 7.40 (d, J=8.6 Hz, 1H, Ar), 6.52 (d, J=8.6 Hz, 1H,
Ar), 6.40 (d, J=2.3 Hz, 1H, Ar), 4.01 (t, J=6.5 Hz, 2H, 1XOCH2), 1.83-1.25 (m,
10H, 5XCH2), 0.89 (t, J=7.1, 3H, 1XCH3).
2-hydroxy-4-n-octyloxybenzaldehyde
Rf = 0.43 in 10% EtOAc-hexane; Yield: 45.0%; A pale yellow liquid; IR (Neat):
2926, 2855, 1629, 1575, 1507cm-1
; 1H NMR (CDCl3,200MHz) δ: 11.47 (s, 1H,
1XOH), 9.7 (s, 1H, 1XCHO), 7.41 (d, J=8.6 Hz, 1H, Ar), 6.52 (d, J=8.6 Hz, 1H,
Ar), 6.40 (d, J=2.3 Hz, 1H, Ar), 4.01 (t, J=6.5 Hz, 2H, 1XOCH2), 1.86-1.30 (m,
12H, 6XCH2), 0.89 (t, J=7.1, 3H, 1XCH3).
2-hydroxy-4-n-nonyloxybenzaldehyde
Rf = 0.45 in 10% EtOAc-hexane; Yield: 43.0%; A pale yellow liquid; IR (Neat):
2960, 2854, 1629, 1575, 1508cm-1
; 1H NMR (CDCl3,200MHz) δ: 11.47(s, 1H,
1XOH), 9.70(s, 1H, 1XCHO), 7.41(d, J=8.6 Hz, 1H, Ar), 6.52(d, J=8.6 Hz, 1H,
Ar), 6.41(d, J=2.3 Hz, 1H, Ar), 4.01(t, J=6.5 Hz, 2H, 1XOCH2), 1.83-1.30 (m,
14H, 7XCH2), 0.89 (t, J=7.1, 3H, 1XCH3).
2-hydroxy-4-n-decyloxybenzaldehyde
Rf = 0.45 in 10% EtOAc-hexane;Yield: 39%; A white solid; m.p: 29oC; IR (Neat):
2926, 2855, 1630, 1575, 1507cm-1
; 1H NMR (CDCl3,200MHz) δ: 11.48 (s, 1H,
1XOH), 9.70 (s, 1H, 1XCHO), 7.41 (d, J=8.6 Hz, 1H, Ar), 6.52 (d, J=8.6 Hz, 1H,
Ar), 6.41 (d, J=2.3 Hz, 1H, Ar), 4.01 (t, J=6.5 Hz, 2H, 1XOCH2), 1.83-1.30 (m,
16H, 8XCH2), 0.89 (t, J=7.1, 3H, 1XCH3).
2-hydroxy-4-n-undecyloxybenzaldehyde
Rf = 0.45 in 10% EtOAc-hexane; Yield: 31%; A white solid; m.p: 44oC; IR
(Neat): 2960, 2854, 1629, 1575, 1507cm-1
; 1H NMR (CDCl3,200MHz) δ: 11.47 (s,
1H, 1XOH), 9.70 (s, 1H, 1XCHO), 7.41 (d, J=8.6 Hz, 1H, Ar), 6.52 (d, J=8.6 Hz,
1H, Ar), 6.41 (d, J=2.3 Hz, 1H, Ar), 4.01 (t, J=6.5 Hz, 2H, 1XOCH2), 1.83-1.30
(m, 18H, 9XCH2), 0.88 (t, J=7.1, 3H, 1XCH3).
2-hydroxy-4-n-hexadecyloxybenzaldehyde
Rf = 0.46 in 10% EtOAc-hexane; Yield: 42%; A white solid; m.p: 55oC; IR
(Neat): 2960, 2854, 1677, 1629, 1575, 1507cm-1
; 1H NMR (CDCl3,200MHz) δ:
11.47 (s, 1H, 1XOH), 9.70 (s, 1H, 1XCHO), 7.41 (d, J=8.6 Hz, 1H, Ar), 6.52 (d,
J=8.6 Hz, 1H, Ar), 6.41 (d, J=2.3 Hz, 1H, Ar), 4.01 (t, J=6.5 Hz, 2H, 1XOCH2),
1.83-1.30 (m, 28H, 14XCH2), 0.88 (t, J=7.1, 3H, 1XCH3).
General procedure for the synthesis of Isophthalic acid bis-{4-[(4-butyloxy-2-
hydroxy-benzylidine)-amino]-phenyl} ester
A mixture of Isophthalic acid bis - (4-amino-phenyl) ester (3) (1 equiv. ), 2-
hydroxy-4-n-alkyloxybenzaldehyde (2. 1 equiv. ), absolute ethanol (20 ml) and a
few traces of acetic acid was refluxed until the yellow solid compound
precipitated out (2 hours). The crude product obtained was collected by filtration
and repeatedly washed with hot absolute ethanol. It was purified by repeated
recrystallization with a mixture of ethanol-CH2Cl2 (9:1).
D-4
Yield: 47%: a yellow solid [found C, 72.78; H, 5.35; N, 4.6.C42H40N2O8 requires
C, 71.98; H, 5.75; N, 4.00]; IR (KBr pellet): 3219, 2938, 1759, 1764, 1619, 1267,
839, 714 cm-1
.¹H NMR (CDCl3,200MHz) δ: 8.91 (t, 1H, Ar), 8.42 (s, 2H, 2X CH-
N), 8.39 (t, 2H, Ar), 7.51 (t, 1H, Ar), 7.37 (d, 2H, Ar), 7.34 (d, 4H, Ar), 7.24 (d,
4H, Ar), 6.36-6.27 (m, 4H, Ar), 4.01 (t, 4H, 2X OCH2), 1.80-1.42 (m, 8H,
4XCH2), 0.89 (t, 6H, 2XCH3)
D-5
Yield: 45%: a yellow solid [found C, 73.01; H, 5.69; N, 3.24.C44H44N2O8 requires
C, 72.51; H, 6.09; N, 3.84]; IR (KBr pellet): 3219, 2938, 1759, 1764, 1619, 1267,
839, 714 cm-1
.¹H NMR (CDCl3,200MHz) δ: 8.92 (t, 1H, Ar), 8.42 (s, 2H, 2X CH-
N), 8.39 (t, 2H, Ar), 7.51 (t, 1H, Ar), 7.37 (d, 2H, Ar), 7.34 (d, 4H, Ar), 7.24 (d,
4H, Ar), 6.36-6.27 (m, 4H, Ar), 4.01(t, 4H, 2X OCH2), 180-1.42 (m,12H,
6XCH2), 0.89 (t, 6H, 2XCH3).
D-6
Yield: 52%: a yellow solid [found C, 73.7; H, 5.79; N, 3.50.C46H48N2O8 requires
C, 73.00; H, 6.39; N, 3.70]; IR (KBr pellet): 3219, 2938, 1759, 1764, 1609, 1267,
839, 724 cm-1
.¹H NMR (CDCl3,200MHz) δ: 8.92 (t, 1H, Ar), 8.42 (s, 2H, 2X CH-
N), 8.39 (t, 2H, Ar), 7.51 (t, 1H, Ar), 7.38 (d, 2H, Ar), 7.34 (d, 4H, Ar), 7.24 (d,
4H, Ar), 6.36-6.27 (m, 4H, Ar), 4.01 (t, 4H, 2X OCH2), 1.80-1.42 (m, 16H,
8XCH2), 0.88 (t, 6H, 2XCH3).
D-7
Yield: 55%: a yellow solid [found C, 74.05; H, 6.88; N, 3.27.C48 H52N2O8 requires
C, 73.45; H, 6.68; N, 3.57]; IR (KBr pellet): 3219, 2937, 1759, 1764, 1609, 1269,
839, 724 cm-1
.¹H NMR (CDCl3,200MHz) δ: 8.92 (t, 1H, Ar), 8.42 (s, 2H, 2X CH-
N), 8.39 (t, 2H, Ar), 7.50 (t, 1H, Ar), 7.38 (d, 2H, Ar), 7.34 (d, 4H, Ar), 7.24 (d,
4H, Ar), 6.36-6.27 (m, 4H, Ar), 4.01 (t, 4H, 2X OCH2), 1.80-1.42 (m, 20H,
10XCH2), 0.88 (t, 6H, 2XCH3).
D-8
Yield: 60%: a yellow solid [found C, 74.57; H, 6.34; N, 4.05.C50H56N2O8 requires
C, 73.87;H,6.94; N,3.45]; IR (KBr pellet): 3219, 2937, 1759, 1764, 1609, 1269,
839, 727 cm-1
.¹H NMR (CDCl3,200MHz) δ: 8.92 (t, 1H, Ar), 8.42 (s, 2H, 2XCH-
N), 8.38 (t, 2H, Ar), 7.50(t, 1H, Ar), 7.38(d, 2H, Ar), 7.34(d, 4H, Ar), 7.24(d, 4H,
Ar), 6.36-6.27 (m, 4H, Ar), 4.01(t, 4H, 2X OCH2), 1.80-1.42(m, 24H, 12XCH2),
0.88 (t, 6H, 2XCH3).
D-9
Yield: 60%: a yellow solid [found C, 74.46; H, 6.69; N, 4.03.C52H60N2O8 requires
C, 74.26; H, 7.19; N, 3.33]; IR (KBr pellet): 3212, 2937, 1759, 1764, 1609, 1269,
836, 727 cm-1
.¹H NMR (CDCl3,200MHz) δ: 8.92 (t, 1H, Ar), 8.42 (s, 2H, 2X CH-
N), 8.38 (t, 2H, Ar), 7.50 (t, 1H, Ar), 7.38 (d, 2H, Ar), 7.34 (d, 4H, Ar), 7.24 (d,
4H, Ar), 6.36-6.27 (m, 4H, Ar), 4.01(t, 4H, 2X OCH2), 1.80-1.42 (m, 28H,
14XCH2), 0.88 (t, 6H, 2XCH3).
D-10
Yield: 60%: a yellow solid [found C,74.33;H,7.72; N,3.22.C54 H64 N2 O8 requires
C, 74.63; H, 7.42; N, 3.22]; IR (KBr pellet): 3212, 2941, 1759, 1764, 1609, 1269,
836, 727 cm-1
.¹H NMR (CDCl3,200MHz) δ:.8.91 (t,1H,Ar), 8.42 (s, 2H, 2X CH-
N), 8.38 (t, 2H, Ar), 7.50 (t,1H, Ar), 7.38 (d, 2H, Ar), 7.34 (d, 4H, Ar), 7.24 (d,
4H, Ar), 6.36-6.29 (m, 4H, Ar), 4.01(t, 4H,2X OCH2), 1.80-1.42
(m,32H,16XCH2), 0.88 (t,6H, 2XCH3).
D-11
Yield: 65%: a yellow solid [found C, 75.77; H, 8.14; N, 3.32.C56H68N2O8 requires
C, 74.97; H, 7.64; N, 3.12]; IR (KBr pellet): 3212, 2941, 1759, 1764, 1609, 1269,
836, 727 cm-1
.¹H NMR (CDCl3,200MHz) δ: 8.91 (t,1H,Ar), 8.42 (s,2H,2XCH-N),
8.38 (t,2H,Ar), 7.50 (t,1H,Ar), 7.38 (d,2H,Ar), 7.34 (d,4H,Ar), 7.24 (d,4H,Ar),
6.36-6.30 (m,4H,Ar), 4.01(t,4H,2XOCH2), 1.80-1.42 (m,36H,18XCH2), 0.88
(t,6H, 2XCH3).
D-16
Yield: 71%: a yellow solid [found C,77.31; H,9.15; N,2.52.C66H88N2O8 requires
C,76.41; H,8.55; N,2.70]; IR (KBr pellet): 3212, 2951,1759, 1765,1609,1269,
839, 723 cm-1
.¹H NMR(CDCl3,200MHz) δ: 8.91(t,1H,Ar), 8.42 (s,2H,2X CH-N),
8.38 (t,2H,Ar), 7.50 (t,1H,Ar), 7.38 (d, 2H, Ar), 7.34 (d,4H,Ar), 7.24 (d, 4H, Ar),
6.36-6.30 (m, 4H, Ar), 4.02 (t,4H,2XOCH2), 1.80-1.42 (m,56H, 28XCH2), 0.89 (t,
6H, 2XCH3).
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