Properties and structural coloured film preparation of some chiral dopants derived from D-Isosorbide

Article abstract of DOI:10.1080/15421406.2020.1864571

A series of chiral dopants derived from D-isosorbide were synthesized. Some of them exhibita monotropicsmecticA phase. Comparison of the melting points of these chiral dopants, the decrease of them is mainly driven by the large entropy change. The helical

Full text of DOI:10.1080/15421406.2020.1864571

Molecular Crystals and Liquid Crystals
ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/gmcl20
Properties and structural coloured film
preparation of some chiral dopants derived from
D-Isosorbide
Shun Wang, Fengmei Fang, Yongmin Guo, Yi Li, Baozong Li & Yonggang Yang
To cite this article: Shun Wang, Fengmei Fang, Yongmin Guo, Yi Li, Baozong Li & Yonggang
Yang (2021): Properties and structural coloured film preparation of some chiral dopants derived
from D-Isosorbide, Molecular Crystals and Liquid Crystals, DOI: 10.1080/15421406.2020.1864571
To link to this article: https://doi.org/10.1080/15421406.2020.1864571
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MOLECULAR CRYSTALS AND LIQUID CRYSTALS
https://doi.org/10.1080/15421406.2020.1864571
Properties and structural coloured film preparation of
some chiral dopants derived from D-Isosorbide
Shun Wanga, Fengmei Fangb, Yongmin Guoa, Yi Lia, Baozong Lia, and
Yonggang Yanga
aState and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of
Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, P.R. China;
bYantaiXianhuaChem-tech Co, Ltd, Yantai, P.R. China
KEYWORDS
ABSTRACT
Chiral dopant; fluorinated;
isosorbide; liquid crystal
A series of chiral dopants derived from D-isosorbide were synthe-
sized. Some of them exhibita monotropicsmecticA phase.
Comparison of the melting points of these chiral dopants, the
decrease of them is mainly driven by the large entropy change. The
helical twisting power (HTP) values of these chiral dopants with
branched alkyl chains, lateral fluoro-substituents and double bonds
are lower than those of the chiral dopants with hexyloxy chains.
Structural colored polymer films with a right-handed helix are pre-
pared using these chiral dopants.
Introduction
Due to their helical structure, cholesteric liquid crystals (CLCs) exhibit unusual physical
properties, such as the selective reflection of circularly polarized light based on the Bragg’s
law [1,2]. Up to now, they have been applied in low energy consumption displays and tun-
able optical or laser devices [3–7]. For the preparation of CLCs, chiral dopants (CDs) are
usually added into achiral nematic liquid crystal (NLC) hosts. The helical pitches of CLCs
can be adjusted by changing the concentrationsand the helical twisting powers (HTPs) of
the CDs [8]. The HTP value is the ability of a CD to produce a helical structure in a given
NLC host, which is calculated as HTP ¼ (Pcw)ꢀ1, where P is the pitch of the chiral nematic
phase, and cw is the weight percentage concentration of the CD. The HTP values of some
CDs are tunable underlight and electric field [9,10].
Excessive CDs will affect the clearing point and the viscosity of the LC mixture. Moreover,
due to the limited solubility of CDs in the LC host, undesirable precipitation may occur
[11–13]. Therefore, to avoid interfering with the original properties of LC matrix materials,
CDs shall possess both high HTP value and high solubility. To date, many CDs with high
HTP and high solubility have been developed, and the relationship between the molecular
structure and the HTP value of CDs has been studied [14–17]. D-Isosorbide (1,4:3,6-dianhy-
dro-D-sorbitol) is a good candidate for the synthesis of CDs due to its chirality and inherent
CONTACT Yi Li
liyi@suda.edu.cn; Yonggang Yang
ygyang@suda.edu.cn
State and Local Joint Engineering
Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science,
Soochow University, Suzhou 215123, P.R. China
ß 2020 Taylor & Francis Group, LLC

2
S. WANG ET AL.
rigidity. In general, isosorbide-based CDs can generate large HTPs, but their poor solubility
in the LC hosts limits their applications [18–20]. In this paper, isosorbide-based dopants with
carbon-carbon double bond, branched alkyl chain and fluorine atom are synthesized accord-
ing to the literature [21]. The HTP values and phase transition behavior of the CDs were
studied. These dopants can be used for the preparation of structural colored polymeric films.
Results and discussion
Nine isosorbide-based CDs, CD-6, CD-6-2F, CD-6-3F, CD-6D, CD-6D-2F, CD-6D-3F,
CD-6E, CD-6E-2F and CD-6E-3F, were synthesized according to the literature (Scheme
1) [21]. Taking into account the economic and environmental issues, the method of
esterification using acyl chloride in the literature was replaced with the p-toluenesul-
fonic acid catalysis or DCC/DMAP methods. The compounds, CD-6, CD-6-2F, CD-6-
3F, CD-6D and CD-6D-2F, were obtained by recrystallization using a acetone/methanol
mixture, while the others were firstly purified by chromatography using petroleum
ether/ethyl acetate/dichloromethane at the volume ratio of 6/0.8/3 and then recrystal-
lization from a acetone/methanol mixture.
The phase transition temperatures and the corresponding enthalpies of the com-
pounds are summarized in Table 1. Differential scanning calorimetry (DSC) was used
to determine the phase transition temperatures, and polarizing optical microscope
(POM) was used to determine the liquid crystalline phases. Compounds, CD-6, CD-6-
2F, CD-6D, CD-6D-2F and CD-6D-3F, exhibit a monotropic SmA phase (Fig. 1). The
small angle X-ray scattering (SAXS) patterns of CD-6D-2F were taken at different tem-
peratures during the cooling process (Fig. 2). A broad peak is found at about 0.46 nm at
100 ꢁC, indicating a fluid smectic phase without in-plane order. The peak at 1.85 nm
should originate from the layer spacing of the SmA phase, which is about half of the
molecular length, indicating that the SmA phase has an intercalation structure ꢀ[122,23].
Two crystalline states are identified at 75 and 60 ꢁC. The q values at 12–15 nm indi-
cate that the lateral molecular packing structures of these two crystals are different.
The phase transition behavior of CD-6 has been reported previously [21]. Herein, a
narrow SmA phase (0.5 K) was identified using POM (Fig. 1a). Due to the steric effect
of the carbon-carbon double bond, the temperature range of the SmA phase of CD-6D
is increased to 1.3 K [24] (Fig. 1d). CD-6D-2F shows the widest SmA phase (34.9 K)
(Fig. 1e). However, the olefination decreases the melting points of the compounds
(Table 1) [25]. The compounds with branched ethyl chains are not liquid crystals and
the melting points of them are lower than the corresponding compounds with straight
alkyl chains. Since the enthalpies of them at the melting points are ultra-high, the low
melting points should be caused by the large entropy changes.
To understand the effect of lateral fluoro-substitution, both enthalpy and entropy
change at the melting point were taken into account. Since enthalpies of CD-6, CD-6-
2F, CD-6D and CD-6D-2F are 35.76, 47.45, 39.81 and 40.69 KJ molꢀ1, respectively, the
intermolecular attractions are enhanced with the lateral fluoro-substitution. It was found
that the melting points of CD-6-2F and CD-6D-2F were lower than those of CD-6 and
CD-6D, respectively. The entropy changes (DS/R) of CD-6 and CD-6-2F at the melting
points are 10.35 and 14.40, respectively. Moreover, the entropy changes (DS/R) of CD-

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
3
Scheme 1. Synthetic routes for the CDs and the molecular structures of C6M, RM105 and IRG651.
6D and CD-6D-2F at the melting points are 11.56 and 12.54, respectively. Therefore,
the decrease of the melting points should be driven by the larger entropy changes [26].
It was also found that the phase transition temperature ranges of CD-6-2F and CD-6D-
2F were wider than those of CD-6 and CD-6D, respectively. The lateral fluoro-substitu-
tion decreased the recrystallization temperature.
The HTP values of the CDs were studied in the commercially available NLC host
(E7) using the Grandjean-Cano method [27]. A certain amount of a CD was added into

4
S. WANG ET AL.
Table 1. Transition temperatures, the corresponding enthalpiesand HTP values of the compounds.
Compound
CD-6
Transition temperature (ꢁC)/ [DH] (KJ molꢀ1
)
HTP (lm–1
)
Cr1 102.4 [ꢀ5.52]Cr2 111.9 [ꢀ1.76] Cr3 142.3 [ꢀ35.76] I 138.5#SmA 138.0
70.1
Cr3 107.3 Cr2 96.3 Cr1
CD-6-2F
CD-6-3F
CD-6D
CD-6D-2F
CD-6D-3F
CD-6E
Cr1 106.1 [ꢀ8.63] 109.6 [7.74] Cr2 123.1 [ꢀ47.45] I 120.4 SmA 104.8 Cr2 104.2 Cr1
Cr1 87.7 [ꢀ16.11] Cr294.7 [ꢀ29.97] I 84.3 Cr2 78.2 Cr1
Cr1 115.9 [ꢀ6.70]Cr2 141.2 [ꢀ39.81] I 131.7 SmA 130.4 Cr2 113.5 Cr1
Cr1 73.56 [ꢀ5.78] Cr2 117.0 [ꢀ40.69] I 110.6 SmA 75.7 Cr2 69.9 Cr1
Cr1 93.1 [ꢀ18.56] Cr2 98.8 [ꢀ4.55] I 82.0 SmA 81.0 Recr
Cr153.3 [9.10] Cr2 93.9 [ꢀ114.12] I 40.9Recr
59.2
59.5
64.2
56.5
56.5
54.7
49.4
50.0
CD-6E-2F
CD-6E-3F
Cr 82.1 [ꢀ142.80] I 41.5 Recr
Cr 88.2†[ꢀ137.84] I
Cr ¼ crystal; SmA ¼ smectic A; I ¼ isotropic liquidꢀa1nd the corresponding enthalpies, DH in kJ molꢀ1 detected on the
second temperature run at a rate of 1.0 ꢁC min
;
#: the data ꢀa1re obtained from POM characterization; †the data are
obtained from the first temperature run at a rate of 1.0 ꢁC min
.
Figure 1. POM images of six compoundstaken during the cooling process. (a) CD-6, the fan-shaped
SmA texture taken at 139.6 ꢁC; (b) CD-6-2F, the fan-shaped SmA texture taken at 119.2 ꢁC; (c) CD-6-
3F, the crystalline texture taken at 86.5 ꢁC;(d) CD-6D, the fan-shaped SmA texture taken at 131.0 ꢁC;(e)
CD-6D-2F, the fan-shaped SmA texture taken at 105.5 ꢁC;(f) CD-6D-3F, the fan-shaped SmA texture
taken at 83.4 ꢁC.
E7 and then heated to the isotropic state. After cooling down to 25 ꢁC, the mixtures
were injected into a wedge-shaped cell. Thirty minutes later, the distance (R) of the
neighboring Cano lines was measured using POM at 25 ꢁC (Fig. 3). The helical pitch
can be obtained from the equation of P ¼ 2 R tanh. h(h ¼ 2.219) is the wedge angle of
the cell. The calculated HTP ((Pcw)ꢀ1) values are in the range of 49.4–70.1 lmꢀ1 (Table
1). CD-6 has the highest HTP value. The HTP values of the CDs decreased by the sub-
stitution of ethyl group and olefination. The mismatch between the branched alkyl
chain (or the alkenyl chain) and straight alkyl chain of E7 was proposed to decrease the

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
5
Figure 2. SAXS patterns of CD-6D-2F taken at different temperatures during the cooling process.
Figure 3. POM images of the mixtures of a CD and E7 in a wedge-shaped cell: CD-6, 0.54 wt%; CD-6-
2F, 0.50 wt%; CD-6-3F, 0.54 wt%; CD-6D, 0.53 wt%; CD-6D-2F, 0.60 wt%; CD-6D-3F, 0.56 wt%; CD-6E,
0.51 wt%; CD-6E-2F, 0.51 wt%; CD-8-3F, 0.53 wt%.
HTP values. The fluoro-substitution can affect the conformations of the CDs and then
affect the HTP values [28]. However, the position of the fluoro-substituent has almost
no effect on the HTP value. For example, the HTP values of CD-6-2F and CD-6-3F are
59.2 and 59.5 lmꢀ1, respectively.
LC polymer films were prepared using a CD, C6M, RM105 and IRG651 at the weight
ratio of 4.3%, 75.8%, 19.0% and 0.9%, respectively, under a 365 nm-UV light [29,30].
The diffuse reflection UV-Vis (DRUV-Vis) and diffuse reflection circular dichroism
(DRCD) spectra are shown in Fig. 4. The wavelengths of the DRUV-vis bands are con-
sistent with those of the DRCD signals, indicating that the reflection bands originate
from the Bragg reflections of the polymer films. Since the DRCD signals are all positive,
the polymer films have a right-handed helix structure (Fig. 4b) [31]. Due to the differ-
ence of the HTP values, the wavelengths of the reflection bands are not same. The
DRCD signals of the polymer films prepared using CD-6, CD-6D and CD-6E appear at
433, 453 and 531 nm, respectively, indicating that the HTP value of CD-6 is the largest.
Although the difference of the LC host will lead to the change of the HTP value, the CDs

6
S. WANG ET AL.
Figure 4. (a) DRUV-vis and (b) DRCD spectra of the films prepared using different CDs.
with different terminal carbon chains maintain the same changing trend in the acrylate
liquid crystal mixtures. For the polymer films prepared using fluorinated CDs, the reflection
wavelengths show red-shifts. Therefore, the fluoro-substitution also causes the decrease of
the HTP value. It was found that the position of the fluoro-substituent also affected the
HTP value. For CD-6 and CD-6D, the HTP values of the derivatives with a fluoro-substitu-
ent at 2-positionwere higher than those of the derivatives with a fluoro-substituent at 3-pos-
ition. However, the HTP value of CD-6E-2F is lower than that of CD-6E-3F.
Conclusion
A series of CDs based on isosorbide for liquid crystals were synthesized. Some of them
exhibit a monotropic SmA phase. The HTP values are tunable by changing the struc-
tures of the terminal chains and fluoro-substitution. Comparison of the melting points
of them, the decrease of them is mainly driven by the large entropy change. Structural
colored polymer films were prepared using these CDs, which were potentially applied as
polarizers and sensors.
Experimental
Characterization
FT-IR spectra were performed on a Nicolet 6700 spectrometer at 2 cmꢀ1 resolution by
1
averaging over 32 scans. The H NMR spectra were taken on a Varian NMR (400 MHz)

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
7
spectrometer in DMSO-d6 solutions using tetramethylsilane (TMS) as an internal stand-
ard at room temperature. Elemental analysis was measured on an EA-1106 instrument.
Mass spectra (MS) were measured with Ultraflextreme MALDI TOF/TOF spectroscope.
The specific rotation measurement was performed using Autopol IV polarimeter. DSC
measurements were conducted on a TA-Q200 under nitrogen at 1.0 ꢁC minꢀ1. The
POM images of the target compounds were taken using a CPV-900C polarization
microscope fitted with a Linkam LTS420 hot stage. The transition temperatures
reported in this paper were the peak values of the transition on DSC traces. Few of
them were the values obtained using POM. SAXS patterns were taken using an X-ray
scattering instrument (SAXSess mc2, Anton Paar) equipped with line collimation and a
2200 W sealed-tube X-ray generator (Cu-Ka, k ¼ 0.154 nm). Diffuse reflectance circular
dichroism (DRCD) spectra were measured using a JASCO 815 spectrometer (Tokyo,
Japan). UV-Vis diffuse reflection spectra were measured by UV-VIS-NIR spectropho-
tometer (UV3600).
Synthesis
Isosorbide was purchased from AccelaChemBio Co., Ltd. 4-Toluenesulfonic acid mono-
hydrate (TsOHꢂH2O), bromohexane, 6-bromo-1-hexene and 1-bromo-iso-octanewas
purchased from AladdinCo., Ltd.4-Hydroxybenzoic acid, 2-fluoro-4-hydroxybenzoic
acid and 3-fluoro-4-hydroxybenzoic acid was purchased from MeryerCo., Ltd. N,N-
Dicyclohexylcarbodiimide (DCC) was purchased from Suzhou Highfine Biotech Co.,
Ltd. 4-Dimethylaminopyridine (DMAP) was obtained from J&K Scientific Ltd.
Tetrahydrofuran (THF) was distilled from sodium benzophenone ketyl in an atmos-
phere of nitrogen. All other chemicals including ethanol (EtOH), dichloromethane
(DCM), petroleum ether (PE) and ethyl acetate (EA) were purchased from Sinopharm
Group Chemical Reagent Co., Ltd and used as received without further purification.
The wedge-shaped cell comes from Zhiya Display Technology (Shenzhen) Co., Ltd.
IRG651, C6M and RM105 were given by Suzhou SoochiralChem. &Tech. Co., Ltd. 4-n-
Hexyloxybenzoic acid, 4-(2-ethyl) hexyloxybenzoic acid and 4-(5-hexenyloxy) benzoic
acid were synthesized according to the literature [32]. Compound 1 was synthesized
according to the literature [33].
D-Isosorbide2,5-bis(2-fluoro-4-hydroxybenzoate) (2)
2-Fluoro-4-hydroxybenzoic acid (18.1 g, 115.9 mmol), isosorbide (8 g, 54.8 mmol) and
TsOHꢂH2O (0.44 g, 2.3 mmol) were added into a 500 mL three-necked flask. Xylene was
used as solvent and stirred at 175 ꢁC for 7 h. The water generated in the reaction was
removed through a water separator. TsOHꢂH2O (0.22 g, 1.1 mmol) was added, and the
reaction continued for 3 h, followed by cooling. The black solid was dissolved in ethyl
acetate and extracted 2 ꢃ 3 times in saturated sodium bicarbonate solution. Activated
carbon adsorbs impurities and recrystallizes in methanol to purify crude products. A
light yellow solid was obtained in 67.1% (15.5 g). FT-IR (cmꢀ1): 3556, 3159 (ꢀO-H), 1724
(ꢀC¼O), 1619, 1592, 1508 and 1458 (ꢀPh).1H NMR (400 MHz, DMSO-d6, 25 ꢁC), d
ꢄ
ꢄ
ꢄ
(TMS, ppm): 3.80–4.03 (m, 4H; -OC HCH2O-), 4.56 (d, J ¼ 4.8 Hz, 1H; -C HC H-),
ꢄ
ꢄ
ꢄ
4.91 (t, J ¼ 5.2 Hz, 1H; -C HC H-), 5.23–5.37 (m, 2H; -COOC HCH2O-), 6.48–6.85 (m,

8
S. WANG ET AL.
4H; 3,5-PhH-), 7.70–7.85 (m, 8.8, 2H; 6-PhH-), 10.88 (s, 2H; -C6H4OH). MS m/z (rel.
int.): 445 (MþþNa, 100). Elemental analysis (%): calcd for C20H16F2O8 (422.08): C:
56.88; H: 3.82. Found: C: 57.09; H: 3.95.
D-Isosorbide2,5-bis(3-fluoro-4-hydroxybenzoate) (3)
The yield is 63.6%. FT-IR (cmꢀ1): 3204 (ꢀO-H), 2886 (ꢀC-H), 1724 (ꢀC¼O), 1622, 1599,
1
1528 and 1440 (ꢀPh). H NMR (400 MHz, DMSO-d6, 25 ꢁC), d (TMS, ppm): 3.88–4.03
ꢄ
ꢄ
ꢄ
(m, 4H; -OC HCH2O-), 4.59 (d, J ¼ 4.8 Hz; -C HC H-), 4.96 (t, J ¼ 5.2 Hz, 1H;
ꢄ
ꢄ
ꢄ
-C HC H-), 5.25–5.37 (m, 2H; -COOC HCH2O-), 7.07 (q, J ¼ 8.0 Hz, 2H; 5-PhH-),
7.67 (dd, J ¼ 11.6, 6.8 Hz, 4H; 2,6-PhH-), 10.95 (s, 2H; -C6H4OH). MS m/z (rel. int.):
445 (MþþNa, 100). Elemental analysis (%): calcd for C20H16F2O8 (422.08): C: 56.88; H:
3.82. Found: C: 56.49; H: 3.73.
D-Isosorbide2,5-bis(2-fluoro-4-(4-(hexyloxy)benzoyloxy)benzoate) (CD-6-2F)
Compound 2 (5.0 g, 11.8 mmol), 4-hexyloxybenzoic acid (6.0 g, 27.2 mmol), DCC (3.5 g,
16.8 mmol), DMAP (0.3 g, 2.6 mmol) were added into a 100 mL eggplant-shaped flask
under nitrogen, and 70 mL THF was used as solvent for two days. After filtration, the
product was purified by recrystallization in an acetone/methanol mixture. A white solid
20
was obtained in 64.3% (6.3 g). Mp: 133.6 ꢁC. [a]D ¼ ꢀ 71.2ꢁ (c ¼ 1.0, CHCl3). FT-IR
1
(cmꢀ1): 2931, 2869 (ꢀC-H, alkyl chain), 1725 (ꢀC¼O), 1604, 1509 and 1468 (ꢀPh). H
NMR (400 MHz, DMSO-d6, 25 ꢁC), d (TMS, ppm): 0.80–0.95 (m, 6H; CH3-), 1.22–1.51
(m, 12H; CH3CH2CH2CH2-), 1.66–1.82 (m, 4H; CH3CH2CH2CH2CH2-), 3.91–4.15 (m,
ꢄ
ꢄ
ꢄ
8H; -CH2OC6H4CO-, -OC HCH2O-), 4.65 (d, J ¼ 4.0 Hz, 1H; -C HC H-), 4.94–5.03
ꢄ
ꢄ
ꢄ
(m, 1H; -C HC H-), 5.31–5.45 (m, 2H; -COOC HCH2O-), 7.13 (d, J ¼ 8.0 Hz, 4H; 3,5-
ꢄ
PhHOCH2CH2-), 7.33 (t, J ¼ 6.4 Hz, 2H; 5-PhHFCOOC H-), 7.43–7.54 (m, 2H; 3-
ꢄ
ꢄ
PhHFCOOC H-), 7.94–8.13 (m, 6H; 2,6- PhHOCH2CH2-, 6-PhHFCOOC H-). MS m/z
(rel. int.): 853 (MþþNa, 100). Elemental analysis (%): calcd for C46H48F2O12 (830.31):
C: 66.50; H: 5.82. Found: C: 66.50; H: 5.76.
D-Isosorbide2,5-bis(3-fluoro-4-(4-(hexyloxy)benzoyloxy)benzoate) (CD-6-3F)
20
The yield is 57.1%. Mp: 97.8 ꢁC. [a]D ¼ ꢀ 68.6ꢁ (c ¼ 1.0, CHCl3). FT-IR (cmꢀ1): 2928,
1
2867 (ꢀC-H, alkyl chain), 1719 (ꢀC¼O), 1603, 1510 and 1469 (ꢀPh). H NMR (400 MHz,
DMSO-d6, 25 ꢁC), d (TMS, ppm): 0.79–0.97 (m, 6H; CH3-), 1.21–1.53 (m, 12H;
CH3CH2CH2CH2-), 1.69–1.82 (m, 4H; CH3CH2CH2CH2CH2-), 3.91–4.18 (m, 8H;
ꢄ
ꢄ
ꢄ
-CH2OC6H4CO-, -OC HCH2O-), 4.68 (d, J ¼ 4.8 Hz, 1H; -C HC H-), 5.04 (t,
ꢄ
ꢄ
ꢄ
J ¼ 5.2 Hz, 1H; -C HC H-), 5.35–5.45 (m, 2H; -COOC HCH2O-), 7.10–7.19 (m, 4H;
ꢄ
3,5-PhHOCH2CH2-), 7.66 (q, J ¼ 7.6 Hz, 2H; 5-PhHFCOOC H-), 7.85–8.00 (m, 4H; 2,6-
ꢄ
PhHFCOOC H-), 8.10 (dd, J ¼ 8.4, 2.0 Hz, 4H; 2,6- PhHOCH2CH2-). MS m/z (rel. int.):
853 (MþþNa, 100). Elemental analysis (%): calcd for C46H48F2O12 (830.31): C: 66.50;
H: 5.82. Found: C: 66.13; H: 5.78.

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
9
D-Isosorbide2,5-bis(4-(4-(5-hexenyloxy)benzoyloxy)benzoate) (CD-6D)
20
The yield is 68.9%. Mp: 144.8 ꢁC. [a]D ¼ ꢀ 86.0ꢁ (c ¼ 1.0, CHCl3). FT-IR (cmꢀ1):
2938, 2872 (ꢀC-H, alkyl chain), 1720 (ꢀC¼O), 1641 (ꢀC¼C), 1603, 1510 and 1469 (ꢀPh).1H
NMR (400 MHz, DMSO-d6, 25 ꢁC),
d
(TMS, ppm): 1.41–1.55 (m, 4H;
CH2¼CHCH2CH2-), 1.66–1.77 (m, 4H; -OCH2CH2-), 1.98–2.13 (m, 4H; CH2¼CHCH2-
ꢄ
), 3.84–4.16 (m, 8.4, 8H; -CH2OC6H4CO-, -OC HCH2O-), 4.61 (d, J ¼ 4.4 Hz, 1H;
ꢄ
ꢄ
ꢄ
ꢄ
-C HC H-), 4.87–5.05 (m, 5H; -C HC H-, CH2¼CH-), 5.29–5.42 (m, 2H;
ꢄ
-COOC HCH2O-), 5.70–5.85 (m, 2H; CH2¼CH-), 7.08 (d, J ¼ 8.0 Hz, 4H; 3,5-
ꢄ
PhHOCH2CH2-), 7.42 (t, J ¼ 7.2 Hz, 4H; 3,5-PhHCOOC H-), 7.94–8.14 (m, 8H; 2,6-
PhH-). MS m/z (rel. int.): 813 (MþþNa, 100). Elemental analysis (%): calcd for
C46H46O12 (790.30): C: 69.86; H: 5.86. Found: C: 70.03; H: 6.16.
D-Isosorbide2,5-bis(2-fluoro-4-(4-(5-hexenyloxy)benzoyloxy)benzoate) (CD-6D-2F)
20
The yield is 72.7%. Mp: 123.5 ꢁC. [a]D ¼ ꢀ 74.6ꢁ (c ¼ 1.0, CHCl3). FT-IR (cmꢀ1):
2941, 2866 (ꢀC-H, alkyl chain), 1724 (ꢀC¼O), 1641(ꢀC¼C), 1604, 1510 and 1470 (ꢀPh).1H
NMR (400 MHz, DMSO-d6, 25 ꢁC),
d
(TMS, ppm): 1.41–1.56 (m, 4H;
CH2¼CHCH2CH2-), 1.64–1.78 (m, 4H; -OCH2CH2-), 2.06 (q, J ¼ 6.8 Hz, 4H;
ꢄ
CH2¼CHCH2-), 3.85–4.14 (m, 8H; -CH2OC6H4CO-, -OC HCH2O-), 4.60 (d, J ¼ 4.8 Hz,
ꢄ
ꢄ
ꢄ
ꢄ
1H; -C HC H-), 4.87–5.10 (m, 5H; -C HC H-, CH2¼CH-), 5.28–5.43 (m, 2H;
ꢄ
-COOC HCH2O-), 5.71–5.86 (m, 2H; CH2¼CH-), 7.09 (d, J ¼ 7.2 Hz, 4H; 3,5-
ꢄ
PhHOCH2CH2-), 7.23–7.33 (m, 2H; 5-PhHFCOOC H-), 7.39–7.50 (m, 2H; 3-
ꢄ
ꢄ
PhHFCOOC H-), 7.89–8.12 (m, 6H; 2,6-PhHOCH2CH2-, 6-PhHFCOOC H-). MS m/z
(rel. int.): 849 (MþþNa, 100). Elemental analysis (%): calcd for C46H44F2O12 (826.28):
C: 66.82; H: 5.36. Found: C: 67.27; H: 5.92.
D-Isosorbide2,5-bis(3-fluoro-4-(4-(5-hexenyloxy)benzoyloxy)benzoate) (CD-6D-3F)
The product was purified by chromatography and further purified by recrystallization
in an acetone/methanol mixture. The product was eluted by PE: EA: DCM ¼ 6: 0.8: 3.
20
A white solid was obtained in 84.4% (6.5 g). Mp: 102.3 ꢁC. [a]D ¼ ꢀ 70.0ꢁ (c ¼ 1.0,
CHCl3). FT-IR (cmꢀ1): 2933, 2871 (ꢀC-H, alkyl chain), 1719 (ꢀC¼O), 1641 (ꢀC¼C), 1605,
1511 and 1471(ꢀPh).1H NMR (400 MHz, DMSO-d6, 25 ꢁC), d (TMS, ppm): 1.44–1.61
(m, 4H; CH2¼CHCH2CH2-), 1.66–1.86 (m, 4H; -OCH2CH2-), 2.11 (q, J ¼ 6.8 Hz, 4H;
ꢄ
CH2¼CHCH2-), 3.92–4.19 (m, 8H; -CH2OC6H4CO-, -OC HCH2O-), 4.68 (d, J ¼ 4.4 Hz,
ꢄ
ꢄ
ꢄ
ꢄ
1H; -C HC H-), 4.90–5.15 (m, 5H; -C HC H-, CH2¼CH-), 5.32–5.50 (m, 2H;
ꢄ
-COOC HCH2O-), 5.76–5.91 (m, 2H; CH2¼CH-), 7.15 (d, J ¼ 7.2 Hz, 4H; 3,5-
ꢄ
PhHOCH2CH2-), 7.66 (dd, J ¼ 15.2, 8.0 Hz, 2H; 5-PhHFCOOC H-), 7.84–8.01 (m, 4H;
ꢄ
2,6-PhHFCOOC H-), 8.10 (d, J ¼ 6.8 Hz, 4H; 2,6-PhHOCH2CH2-). MS m/z (rel. int.):
849 (MþþNa, 100). Elemental analysis (%): calcd for C46H44F2O12 (826.28): C: 66.82;
H: 5.36. Found: C: 66.89; H: 5.80.
D-Isosorbide2,5-bis(-4-(4-(2-ethylhexyloxy)benzoyloxy)benzoate) (CD-6E)
20
The yield is 62.8%. Mp: 101.9 ꢁC. [a]D ¼ ꢀ 74.2ꢁ (c ¼ 1.0, CHCl3). FT-IR (cmꢀ1):
2928, 2873 (ꢀC-H, alkyl chain), 1717 (ꢀC¼O), 1601, 1508 and 1462 (ꢀPh). 1H NMR
(400 MHz, DMSO-d6, 25 ꢁC), d (TMS, ppm): 0.76–1.03 (m, 12H; CH3CH2-), 1.17–1.57

10
S. WANG ET AL.
(m, 16H; CH3CH2CH2CH2CH-, -CH2CH3), 1.63–1.82 (m, 2H; -CH2CH2CH-), 3.90–4.12
ꢄ
ꢄ
ꢄ
(m, 8H; -CH2OC6H4CO-, -OC HCH2O-), 4.67 (d, J ¼ 4.0 Hz, 1H; -C HC H-), 5.02 (t,
ꢄ
ꢄ
ꢄ
J ¼ 5.2 Hz, 1H; -C HC H-),5.32–5.46 (m, 2H; -COOC HCH2O-), 7.14 (d, J ¼ 7.2 Hz,
ꢄ
4H; 3,5-PhHOCH2CH2-), 7.44 (dd, J ¼ 7.6, 6.8 Hz, 4H; 3,5-PhHCOOC H-), 7.97–8.18
(m, 8H; 2,6-PhH-). MS m/z (rel. int.): 873 (MþþNa, 100). Elemental analysis (%): calcd
for C50H58O12 (850.39): C: 70.57; H: 6.87. Found: C: 70.64; H: 6.90.
D-Isosorbide2,5-bis(2-fluoro-4-(4-(2-ethylhexyloxy)benzoyloxy)benzoate) (CD-6E-2F)
20
The yield is 55.8%. Mp: 86.4 ꢁC. [a]D ¼ ꢀ 62.6ꢁ (c ¼ 1.0, CHCl3). FT-IR (cmꢀ1): 2929,
1
2873 (ꢀC-H, alkyl chain), 1728 (ꢀC¼O), 1604, 1510 and 1463 (ꢀPh). H NMR (400 MHz,
DMSO-d6, 25 ꢁC), d (TMS, ppm): 0.78–0.98 (m, 12H; CH3CH2-), 1.17–1.56 (m, 16H;
CH3CH2CH2CH2CH-, -CH2CH3), 1.63–1.80 (m, 2H; -CH2CH2CH-), 3.88–4.13 (m, 8H;
ꢄ
ꢄ
ꢄ
-CH2OC6H4CO-, -OC HCH2O-), 4.65 (d, J ¼ 4.0 Hz, 1H; -C HC H-), 5.00 (t,
ꢄ
ꢄ
ꢄ
J ¼ 4.4 Hz, 1H; -C HC H-), 5.32–5.48 (m, 2H; -COOC HCH2O-), 7.14 (d, J ¼ 8.0 Hz,
ꢄ
4H; 3,5-PhHOCH2CH2-), 7.33 (t, J ¼ 7.2 Hz, 2H; 5-PhHFCOOC H-), 7.48 (dd,
ꢄ
J ¼ 11.2,6.8 Hz, 2H; 3-PhHFCOOC H-), 7.94–8.15 (m, 6H; 2,6-PhHOCH2CH2-, 6-
þ
ꢄ
PhHFCOOC H-). MS m/z (rel. int.): 909 (M þNa, 100). Elemental analysis (%): calcd
for C50H56F2O12 (886.37): C: 67.71; H: 6.36. Found: C: 67.56; H: 6.51.
D-Isosorbide2,5-bis(3-fluoro-4-(4-(2-ethylhexyloxy)benzoyloxy)benzoate) (CD-6E-3F)
20
The yield is 60.5%. Mp: 88.2 ꢁC. [a]D ¼ ꢀ 69.2ꢁ (c ¼ 1.0, CHCl3). FT-IR (cmꢀ1): 2930,
2873 (ꢀC-H, alkyl chain), 1718 (ꢀC¼O), 1604, 1511 and 1462 (ꢀPh).1H NMR (400 MHz,
DMSO-d6, 25 ꢁC), d (TMS, ppm): 0.74–1.01 (m, 12H; CH3CH2-), 1.17–1.55 (m, 16H;
CH3CH2CH2CH2CH-, -CH2CH3), 1.66–1.79 (m, 2H; -CH2CH2CH-), 3.90–4.18 (m, 8H;
ꢄ
ꢄ
ꢄ
-CH2OC6H4CO-, -OC HCH2O-), 4.68 (d, J ¼ 4.4 Hz, 1H; -C HC H-), 5.09 (t,J ¼ 4.4 Hz,
ꢄ
ꢄ
ꢄ
1H; -C HC H-), 5.29–5.50 (m, 2H; -COOC HCH2O-), 7.16 (d, J ¼ 8.4 Hz, 4H; 3,5-
ꢄ
PhHOCH2CH2-), 7.65 (q, J ¼ 7.6 Hz, 2H; 5-PhHFCOOC H-), 7.82–8.02 (m, 4H; 2,6-
ꢄ
PhHFCOOC H-), 8.10 (d, J ¼ 8.0 Hz, 4H; 2,6- PhHOCH2CH2-). MS m/z (rel. int.): 909
(MþþNa, 100). Elemental analysis (%): calcd for C50H56F2O12 (886.37): C: 67.71; H:
6.36. Found: C: 67.52; H: 6.40.
Preparation of polymer films
160 mg of C6M, 40 mg of RM105, 9 mg of a CD and 2 mg of IRG651 are dissolved in
2 mL of THF. After removing THF on the surface of a glass slide at 120 ꢁC, another
glass slide is covered. Then, the liquid crystal mixture is cooled down to 60 ꢁC. The
polymer film is obtained by photopolymerization using a 365-nm UV lamp.
Funding
This work was supported by the Project of Scientific and Technologic Infrastructure of Suzhou
(SZS201905) and the National Natural Science Foundation of China (No. 51473141).

MOLECULAR CRYSTALS AND LIQUID CRYSTALS
11
ORCID
Yonggang Yang
http://orcid.org/0000-0003-0185-7471
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