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7740 Ha et al.
Asian J. Chem.
n-decanoyloxy to n-tetradecanoyloxy derivatives. Excessive
length of alkyl chain in n-hexadecanoyloxy and n-octadeca-
noyloxy derivatives has caused the mesophase diminished;
therefore, these compounds are non-mesogens.
2500
2000
SmA, cooling, at 65 °C, 12ABFA
ACKNOWLEDGEMENTS
1500
1000
500
0
The authors thank Universiti Tunku Abdul Rahman and
Ministry of Higher Education Malaysia for the financial
supports and research facilities. The powder XRD measurements
were supported by Beamline BL17A (charged by Dr. Jey-Jau
Lee) of the National Synchrotron Radiation Research Center,
Taiwan.
0
2
4
6
8
10 12 14 16 18 20 22 24
(°)
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2
θ
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215.1
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43.1
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355.2
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287.1306.1323.1
40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400
m/z
Fig. 6. EI-MS spectrum of 12ABFA
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1H NMR spectrum of 12ABFA shows two triplet signals
at δ = 0.9 and 2.6 ppm, which were, respectively ascribed
to the methyl (CH3–) and methylene protons of -CH2COO-Ar.
Methylene protons due to the long alkyl chain {-(CH2)8-}
exhibited the multiplet peaks at δ = 1.3-1.5 ppm. Eight aromatic
protons exhibited multiplet signals at the chemical shifts range
of δ = 7.1-7.9 ppm. Imine proton was observed as singlet signal
at the most downfield region, δ = 8.4 ppm18. The 13C signal at
δ = 14.09 ppm was attributed to the methyl carbon while the
signals observed at chemical shifts range of δ = 22.67-34.43
ppm are belonged to the methylene carbons of the long alkyl
chain. Signals resonated between δ = 115.71-162.90 ppm is
belonged two twelve aromatic protons. Whilst signal attributed
to azomethine carbon showed signal at δ = 158.85 ppm, carbonyl
carbon exhibited signal at δ = 171.91 ppm.
Conclusion
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Takanishi and H. Takezoe, Liq. Cryst., 33, 979 (2006).
The synthesis and mesomorphic behavior of homologous
series of 4-alkanoyloxybenzylidene-4-fluoroaniline is reported
in the current paper. Smectic A phase was observed from the