Synthesis and mesomorphic properties of chiral esters comprising partially fluorinated alkoxyalkoxy terminal chains and a 1-methylheptyl chiral moiety

Article abstract of DOI:10.1080/15421400802432428

Two structurally similar homologous series of chiral esters with partially fluorinated alkoxyalkoxy terminal chains are described. Their synthetic routes and mesomorphic properties, such as phase transitions temperatures and enthalpies, are characterized by polarizing optical microscope and differential scanning calorimetry.

Full text of DOI:10.1080/15421400802432428

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Synthesis and Mesomorphic
Properties of Chiral Esters
Comprising Partially
Fluorinated Alkoxyalkoxy
Terminal Chains and a 1-
methylheptyl Chiral Moiety
M. Żurowska a , R. Dąbrowski a , J. Dziaduszek a , K.
Czupryński a , K. Skrzypek a & M. Filipowicz a
a Institute of Chemistry, Military University of
Technology , Warsaw, Poland
Published online: 30 Jan 2009.
To cite this article: M. Żurowska , R. Dąbrowski , J. Dziaduszek , K. Czupryński , K.
Skrzypek & M. Filipowicz (2008) Synthesis and Mesomorphic Properties of Chiral Esters
Comprising Partially Fluorinated Alkoxyalkoxy Terminal Chains and a 1-methylheptyl
Chiral Moiety, Molecular Crystals and Liquid Crystals, 495:1, 145/[497]-157/[509],
DOI: 10.1080/15421400802432428
To link to this article: http://dx.doi.org/10.1080/15421400802432428
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Mol. Cryst. Liq. Cryst., Vol. 495, pp. 145=[497]–157=[509], 2008
Copyright # Taylor & Francis Group, LLC
ISSN: 1542-1406 print=1563-5287 online
DOI: 10.1080/15421400802432428
Synthesis and Mesomorphic Properties of Chiral Esters
Comprising Partially Fluorinated Alkoxyalkoxy Terminal
Chains and a 1-methylheptyl Chiral Moiety
˙
M. Zurowska, R. Da˛browski, J. Dziaduszek,
´
K. Czuprynski, K. Skrzypek, and M. Filipowicz
Institute of Chemistry, Military University of Technology, Warsaw,
Poland
Two structurally similar homologous series of chiral esters with partially
fluorinated alkoxyalkoxy terminal chains are described. Their synthetic routes
and mesomorphic properties, such as phase transitions temperatures and enthal-
pies, are characterized by polarizing optical microscope and differential scanning
calorimetry.
Keywords: enthalpies; fluorinated AFLCs; phase transitions; synthesis
1. INTRODUCTION
Partially fluorinated three ring esters have high tilted (up to
45ꢀ–orthoconic) antiferroelectric phase and show unusual optical
properties, which produce perfect dark state and in the consequence
high contrast [1]. They are very perspective for many applications.
Many homologous series of esters of general formula (I) with
perfluoroalkanoyl unit in the terminal chain have been prepared
recently [2–4]
where p1 ¼ 1 and p2 ¼ 2 or p1 ¼ 2 and p2 ¼ 1; r ¼ 3–6.
The work was carried under Polish Ministry of Science and Information N204 029
31=0512 support and PBS 765.
Address correspondence to M. Zurowska, Institute of Chemistry, Military University
of Technology, Warsaw 00-908, Poland. E-mail: mzurowska@wat.edu.pl
145=[497]

˙
M. Zurowska et al.
146=[498]
They have low melting point and low melting enthalpy, which
enable to formulate orthoconic mixtures existing in a broad tempera-
ture range. Unfortunately they have very short helical pitch at room
temperature, so well unwounded helical structure is possible to obtain
only in very thin cells (ꢁ1 mm) [4]. We are looking for the liquid crystal-
line materials with longer pitch so the compounds with partially
fluorinated alkoxyalkoxy terminal chain are prepared.
The ten compounds expressed by general formula (II)
with r ¼ 3, 5, 6, and X1 ¼ H, X2 ¼ F or X1 ¼ F, X2 ¼ H or X1 ¼ X2 ¼ H or
X1 ¼ X2 ¼ F are described here.
2. SYNTHESIS
Synthesis of the esters was carried out by treating chiral phenol (C)
with benzoic acid chloride (B) [4], see Scheme 1.
The efficient preparation of high optical purity phenol (C) was
described recently in Ref. [5].
SCHEME 1 Synthetic route of esters with fluoroalkoxyalkoxy chain (II).

Fluorinated Antiferroelectric Liquid Crystals
147=[499]
The laterally substituted (X1 ¼ H, X2 ¼ F; X1 ¼ F, X2 ¼ H) and
unsubstituted (X1 ¼ X2 ¼ H) fluoroalkoxyalkoxy benzoic acids (A) were
prepared using perfluoroalkoxyalkoxy alcohol according to the
Scheme 2.
SCHEME 2 Synthetic route of fluoroalkoxyalkoxy benzoic acids with X1 ¼ H,
X2 ¼ F; X1 ¼ F, X2 ¼ H; X1 ¼ X2 ¼ H (A).

˙
M. Zurowska et al.
148=[500]
SCHEME 3 Synthetic route of fluoroalkoxyalkoxy benzoic acids with
X1 ¼ X2 ¼ F (A1).
In case of bilaterally substituted (X1 ¼ X2 ¼ F) fluoroalkoxyalkoxy
benzoic acids (A1) the method shown on Scheme 3 was more
convenient.
3. EXPERIMENTAL PART
All reagents were used for reactions as purchased, only toluene was
dried by distillation over diphosphorus pentaoxide.
Purity of the liquid crystalline esters was recorded using Schimadzu
prominence chromatograph with HPLC MS (API-ESI) detector
2010EV. Purity of the other compounds was checked using Hewlett-
Packard HP-6890N chromatograph with MS detector HP5973N.

Fluorinated Antiferroelectric Liquid Crystals
149=[501]
ðSÞ-ð1Þ-4-hydroxy-40-ð1-methylheptylcarbonylÞbiphenyl
m.p.: 86.1ꢀC [5]
1. (S)-(1)-40-1-methylheptylcarbonyl)biphenyl-4-yl
4-[6-4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]-2-
fluorobenzoate
To the suspension of 4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-
oxy]-2-fluorobenzoic acid (4.5 g; 10 mmol) in dry toluene (ꢁ100 ml),
oxalyl chloride (1 ml; 11 mmol) and one drop of N,N-dimethylforma-
mide were added. Vigorous reaction occurs. When the evolution of
gases was stopped, mixture was heated at 30ꢀC with stirring for
2 hours. The clear solution was then refluxed and the excess of oxa-
lyl chloride was distilled off with toluene (ꢁ25 ml) using Vigreux
column. Then (S)-(þ)-4-hydroxy-40-(1-methylheptylcarbonyl)biphenyl
(3.26 g; 10 mmol) and pyridine (1.6 ml; 20 mmol) were added to
the cold solution. The mixture was stirred at 60ꢀC for 2 days, then
it was cooled down to room temperature and poured into the sol-
ution prepared from concentrated hydrochloric acid (ꢁ2 ml) and
water (ꢁ200 ml). The layers were separated, the organic layer
was washed twice with water. The extract was filtered off by the
layer of active carbon. Then it was dried over anhydrous magnes-
ium sulfate and the solvent was evaporated to dryness. The
crude-coloured product was crystallized from anhydrous ethanol
and acetone (2:1). The obtained solid was purified using column
chromatography on silica gel with methylene chloride as eluent.
Then ester was recrystallized from anhydrous ethanol
and acetone. Yield: 6.2 g; phase transitions of ester are presented
in Table 1.
Purity: 98.95%; m.p.: 44.8ꢀC
MS: 769(M þ Naþ), 747(M þ Hþ)
The other – nine liquid crystals were obtained in the same way and
crystallized from anhydrous ethanol and acetone:
2. (S)-(1)-40-1-methylheptylcarbonyl)biphenyl-4-yl
4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]-
3-fluorobenzoate
Purity: 99.35%; m.p.: 57.5ꢀC
MS: 769(M þ Naþ), 747(M þ Hþ)

˙
M. Zurowska et al.
150=[502]
TABLE 1 Phase transitions temperatures [ꢀC] and enthalpies [kJ ꢂ molꢃ1] of
esters 1–10
No r X1 X2 Cr
SmCAꢄnti
SmCꢄ
105.4–105.7
SmA
Iso
44.2–44.8
42.2
34.2
57.5
57.3
24.3
64.5–65.0
62.6
23.2
62.0–63.0
60.5
24.0
–
28.1
34.9
63.6–64.0
68.7
25.4
–
53.5
74.9–75.9
73.9
0.038
81.7–83.9
80.1
0.017
85.0–85.7
84.8
0.013
95.7–97.0
94.7
0.025
105.8–107.1
(108.5)
2.1
114.4–114.9
112.7
4.4
114.0–114.8
112.8
3.9
128.2–128.6
126.3
4.1
101.0–101.4
99.0
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
1 6 H
F
H
F
103.7
4.6
110.4–110.8
108.5
1.15
112.1–112.5
110.5
0.8
126.7–126.8
124.8
1.47
(100.2)
–
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
2 6
3 6
F
F
4 6 H
5 5 H
H
F
100.1–100.4
(97.0)
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
ꢄ
0.1
–
5.4
108.8–108.9
–
108.9–109.0
106.8
1.4
110.2–110.4
107.7
1.1
125.9–126.3
123.3
(111.4–111.6)
109.6
ꢄ
ꢄ
6 5
7 5
F
F
H
F
–
3.7
111.5–111.8
109.2
109.7–110.0
(106.7)
0.038
123.1–123.6
121.0
21.6
67.3–68.0
66.8
18.0
51.5–55.3
51.2
3.9
8 5 H
H
H
H
–
–
–
0.09
99.4–100.5
98.9
5.8
9 3
F
–
–
24.7
6.0
80.7–81.0
54.5; 78.9
3.5; 21.6
118.0–118.8
116.2
10 3 H
7.1
Upper row – temperature from microscope observations; central row – temperature from
DSC observations; down row – enthalpies; ( ) – temperature obtained during cooling cycle.
3. (S)-(1)-40-(1-methylheptylcarbonyl)biphenyl-4-yl
4- [6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]-2,3-
difluorobenzoate
Purity: 98.5%; m.p.: 65.0ꢀC
MS: 787(M þ Naþ)
4. (S)-(1)-40-1-methylheptylcarbonyl)biphenyl-4-yl 4-[6-
(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]oxy] benzoate
Purity: 99.9%; m.p.: 63.0ꢀC
MS: 751(M þ Naþ)

Fluorinated Antiferroelectric Liquid Crystals
151=[503]
5. (S)-(1)-40-(1-methylheptylcarbonyl)biphenyl-4-yl
4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy]-2-
fluorobenzoate
Purity: 99.9%
MS: 755(M þ Naþ)
6. (S)-(1)-40-(1-methylheptylcarbonyl)biphenyl-4-yl
4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy]-3-
fluorobenzoate
Purity: 99.4%; m.p.: 64.0ꢀC
MS: 755(M þ Naþ)
7. (S)-(1)-40-(1-methylheptylcarbonyl)biphenyl-4-yl
4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy]-2,3-
difluorobenzoate
Purity: 98.1%
MS: 773(M þ Naþ)
8. (S)-(1)-40-(1-methylheptylcarbonyl)biphenyl-4-yl
4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy] benzoate
Purity: 99.7%; m.p.: 68.0ꢀC
MS: 737(M þ Naþ), 715(M þ Hþ)
9. (S)-(1)-40-(1-methylheptylcarbonyl)biphenyl-4-yl
4-[3-(4,4,4,3,3,2,2-heptafluorobutoxy)prop-1-oxy]-3-
fluorobenzoate
Purity: 99.9%; m.p.: 55.3ꢀC
MS: 703(M þ Naþ)
10. (S)-(1)-40-(1-methylheptylcarbonyl)biphenyl-4-yl
4-[3-(4,4,4,3,3,2,2-heptafluorobutoxy)prop-1-oxy]
benzoate
Purity: 99.9%; m.p.: 81.0ꢀC
MS: 685(M þ Naþ)
4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hexyl-1]
benzenesulfonate
The mixture of 6-(4,4,4,3,3,2,2-heptafluorobutoxy) hexanol-1 (27 g;
90 mmol), pyridine (14.5 ml; 180 mmol) and methylene chloride

˙
M. Zurowska et al.
152=[504]
(ꢁ160 ml) was cooled down to 0–5ꢀC using acetone and dry ice and
benzene sulfonyl chloride (12.7 ml; 99 mmol) was dropped over 2 hours
with stirring and cooling to approximately 0ꢀC. The reaction mixture
was still stirred at the same temperature for 4 h. Then it was poured
into water with crashed ice and stirred for 15 minutes. The organic
layer was separated and washed twice with water and ice and twice
with diluted hydrochloric acid (ꢁ1%) and again three times with iced
water. The organic layer was separated from aqueous layer and dried
over anhydrous magnesium sulfate. The solution was filtered through
the fluted filter paper to remove the drying medium and the solvent
was removed under reduced pressure. The liquid crude product was
used to alkylation. Yield: 36.8 g.
4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pentyl-1]
benzenesulfonate and 4-[3-(4,4,4,3,3,2,2-heptafluorobutoxy)
propyl-1] benzenesulfonate
Obtained the same as 4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]
benzenesulfonate.
ethyl 4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]-2-
flurobenzoate
4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hexyl-1] benzenesulfonate (36.8 g;
84 mmol),ethyl4-hydroxy-2-fluorobenzoate(15.5 g;84 mmol),potassium
carbonate (23.2 g; 168 mmol) and 2-butanone (ꢁ150 ml) were refluxed
with stirring for 2 days. The mixture was cooled down and poured into
water (ꢁ2 l) and stirred for 3 hours. The solution was extracted three
times with methylene chloride. The combined organic layers were
washed twice with water and separated using separator funnel. Then
the organic layer was filtered through an active carbon and dried over
anhydrous magnesium sulfate. The solvent was removed on the rotary
evaporator. The crude product was used to hydrolysis. Yield: 37.2 g.
Purity: 99.4%
MS: 466(Mþ), 421, 213, 184, 156, 139, 83, 55, 29
The other esters were obtained the same as ethyl 4-[6-(4,4,4,3,3,2,2-
heptafluorobutoxy)hex-1-oxy] 2-fluorobenzoate:
ethyl 4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]-3-
flurobenzoate
Purity: 96.8%
MS: 466(Mþ), 213, 184, 156, 139, 83, 55, 29

Fluorinated Antiferroelectric Liquid Crystals
153=[505]
ethyl 4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]
benzoate
Purity: 88.1%
MS: 448(Mþ), 403, 213, 166, 138, 83, 55
ethyl 4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy]-2-
fluorobenzoate
Purity: 93.0%
MS: 452(Mþ), 213, 139, 69, 41
ethyl 4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy]-3-
fluorobenzoate
Purity: 89.0%
MS: 452(Mþ), 407, 269, 213, 184, 156, 69, 41
ethyl 4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy]
benzoate
Purity: 87.9%
MS: 434(Mþ), 389, 269, 213, 166, 138, 69, 41
ethyl 4-[3-(4,4,4,3,3,2,2-heptafluorobutoxy)prop-1-oxy]-3-
fluorobenzoate and ethyl 4-[3-(4,4,4,3,3,2,2-
heptafluorobutoxy)prop-1-oxy]benzoate4-[6-(4,4,4,3,3,2,2-
heptafluorobutoxy)hex-1-oxy]-2-fluorobenzoic acid
Ethyl 4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]-2-fluorobenzo-
ate (37.2 g; 79 mmol), potassium hydroxide (11.2 g; 200 mmol), ethanol
(ꢁ100 ml) and water (ꢁ10 ml) were refluxed with stirring for 4 hours.
The progress of reaction was monitored by TLC. Then the reaction
mixture was cooled down, poured into water (ꢁ800 ml), acidified with
concentrated hydrochloric acid (ꢁ20 ml) and stirred for 2 hours; pH
of solution was checked by indicator paper. The formed precipitate
was collected by filtration, washed with water and crystallized from
ethanol and water (ꢁ2:1). Yield: 28.6 g.
Purity: 97.8%
MS: 438(Mþ), 213, 156, 139, 83, 55, 41, 29
The other acids were obtained the same as 4-[6-(4,4,4,3,3,2,2-hepta-
fluorobutoxy)hex-1-oxy]-2-fluorobenzoic acid and crystallized from
ethanol and water.

˙
M. Zurowska et al.
154=[506]
4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]
3-fluorobenzoic acid
Purity: 99.9%
MS: 438(Mþ), 213, 156, 139, 83, 55, 41, 29
4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy] benzoic acid
Purity: 99.8%
4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy]-2-
fluorobenzoic acid
Purity: 99.5%
4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy]-3-
fluorobenzoic acid
Purity: 99.9%
4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy] benzoic acid
Purity: 99.8%
4-[3-(4,4,4,3,3,2,2-heptafluorobutoxy)prop-1-oxy]-3-
fluorobenzoic acid
Purity: 99.9%
4-[3-(4,4,4,3,3,2,2-heptafluorobutoxy)prop-1-oxy] benzoic acid
Purity: 98.8%
4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]-2,3-
difluorobenzene
4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hexyl-1]benzenesulfonate(112.8 g;
256 mmol), 4-hydroxy-2,3-difluorobenzene (27.7 g; 213 mmol), potass-
ium carbonate (58.7 g; 426 mmol) and 2-butanone (ꢁ600 refluxed with
stirring for 10 hours. The mixture was cooled down and poured into
water (ꢁ2000 stirred for 3 hours. The solution was extracted
three times with methylene chloride. The combined organic layers
were washed twice with water and separated. Then the organic layer
was filtered through an active carbon and dried over anhydrous

Fluorinated Antiferroelectric Liquid Crystals
155=[507]
magnesium sulfate. The solvent was removed on the rotary evapor-
ator. The liquid product was purified using vacuum distillation. The
product was used to acylation. Yield: 67.9 g.
Purity: 93.3%
MS: 412(Mþ), 213, 130, 83, 55, 29
4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy]-2,3-
difluorobenzene
Obtained the same as 4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-
oxy]-2,3-difluorobenzene.
Purity: 91.9%
MS: 398(Mþ), 269, 213, 130, 69, 41
4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]-2,3-
difluoroacetophenone
Acyl chloride (17 ml; 240 mmol) was dropped slowly to the stirred
mixture of aluminium chloride (30.8 g; 231 mmol) and dry methylene
chloride (ꢁ200 ml). When the homogeneous solution was prepared,
the mixture was cooled down to 0–5ꢀC and 4-[6-(4,4,4,3,3,2,2-hepta-
fluorobutoxy)hex-1-oxy]-2,3-difluorobenzene (67.9 g; 165 mmol) was
added dropwise over a period of 1 hour. After dropping was completed
the mixture was stirred at 0–5ꢀC for 4 hours. Then it was poured into
water with crashed ice and stirred. The layers were separated, the
organic layer was washed three times with water, then the solution
was transferred to the separatory funnel, extracted with methylene
chloride and separated precisely. The extract was dried over anhydrous
magnesium sulfate and the solvent was removed using the rotary evap-
orator. The liquid product was distilled using vacuum. The product was
used to haloform reaction without further purification. Yield: 51.5 g.
Purity: 80.2%
MS: 454(Mþ), 213, 157, 83, 55, 29
4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy]-2,
3-difluoroacetophenone
Obtained the same as 4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-
oxy]-2,3-difluoroacetophenone.
Purity: 89.8%
MS: 440(Mþ), 269, 213, 172, 157, 69, 41

˙
M. Zurowska et al.
156=[508]
4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]-2,3-
difluorobenzoic acid
To the stirred hypobromite solution prepared from sodium hydroxide
water solution (72.3 g in 68 ml of water), crushed ice (226 g) and bromine
(72.3 g; 23.2 ml), 4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]-2,
3-difluoroacetophenone dissolved in 300 ml of 1,4-dioxane was added
in one portion. The temperature was increased to 25ꢀC very quickly,
because the exothermic reaction occurs. When the temperature
started to decrease, the further reaction was initiated by gentle heat-
ing on the water bath. When the reaction stopped, a new solution of
hypobromite prepared the same and 200 ml of 1,4-dioxane were
added to the reaction mixture. The temperature was increased to
about 25ꢀC once again. The colour of the stirred reaction mixture
was turned light. Then the mixture was heated at about 60ꢀC for 2
hours using water bath. After that it was cooled down to the room
temperature, discoloured using sodium pyrosulfite, poured into water
with hydrochloric acid and stirred for 2 hours; pH of solution was
checked by indicator paper. The precipitate was formed and it was
filtered through the filter paper and washed with plenty of water.
The solid product was crystallized from methanol. Yield: 31.0 g.
4-[5-(4,4,4,3,3,2,2-heptafluorobutoxy)pent-1-oxy]-2,
3-difluorobenzoic acid
Obtained the same as 4-[6-(4,4,4,3,3,2,2-heptafluorobutoxy)hex-1-oxy]-
2,3-difluorobenzoic acid. Crystallization from methanol.
4. MESOMORPHISM OF PREPARED COMPOUNDS
The sequence of phases and phase transitions temperatures of the
liquid crystals were measured by texture observation in ‘‘Biolar’’ polar-
izing microscope (PZO) equipped with ‘‘Linkam’’ TMS-93 hot stage.
The temperatures of phase transitions and enthalpies were recorded
by DSC ‘‘Setaram’’ 141 microcalorimeter in heating and cooling cycles.
The results of measurements in heating cycle are listed below in the
Table 1.
The all compounds have anticlinic smectic phase (SmCAꢄnti ) in a
broad temperature range and synclinic smectic phase (SmCꢄ) and
orthogonal smectic phase (SmA) above it in short temperature range,
see the Table 1. Temperature range of SmCꢄ phase and SmA phase is
smaller in series r ¼ 5 than in series r ¼ 6. In case of compound 8 the

Fluorinated Antiferroelectric Liquid Crystals
157=[509]
SmA phase disappeares totally. For the compounds with r ¼ 3 the
direct phase transition SmCAꢄnti – Iso was observed [4].
5. CONCLUSIONS
The compounds with partially fluorinated alkoxyalkoxy terminal
chain have antiferroelectric phase in a broad temperature range simi-
lar to the compounds with partially fluorinated alkanoyloxyalkoxy
chain. Longer methylene spacer promotes the presence ferroelectric
phase (SmCꢄ).
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