Paper
CrystEngComm
theory; in particular,
thermodynamics of the process and a wider variety of
halogen-substituted salicylideneanilines should be
considered. The present study provides insight regarding the
kinetic stability of polymorphs, which will contribute a
diverse range of fields including pharmaceuticals, foods,
dyes/pigments, and organic electronics.
a
theoretical evaluation of the
ArH, 1H), 7.37 (d, ArH, 1H), 7.41 (m, ArH, 2H), δ 8.54
(sH, –NCH–, 1H), 13.02 (br, OH, 1H), 13C NMR (CDCl3)
δ 118.88, 119.73, 122.46, 123.78, 129.63, 131.30, 132.99,
133.19, 146.44, 159.61, 161.58.
Crystallography
For X-ray diffraction of single crystals, data were collected on
a VariMax DW with Saturn CCD, λ (Mo Kα) = 0.71075 Å. The
structures were solved by direct method (SHELXS-2013)48 and
refined on F2 by full-matrix least-square techniques (SHELXL-
2018).49 Crystallographic data have been deposited with
Cambridge Crystallographic Data Centre: Deposition number
CCDC-2001051, 2001052, 2001053 for 4CC-o, 4CC-y, 5CC-o.
Experimental section
Measurements
The thermal behavior of the solid samples were observed
with a conventional optical microscope equipped with a
temperature-controlled stage (Linkam THMS600). The
ultraviolet-visible (UV-vis) absorption spectra of the solid
Definitions
samples were acquired using
a
conventional optical
microscope equipped with an optical fiber connected to a
spectrometer (Ocean Optics USB4000) and the above-
mentioned temperature-controlled stage. The measurement
light was guided from a halogen lamp (100 W). Differential
scanning calorimetry was carried out in Perkin-Elmer Pyris 1
DSC at a heating rate of 10 K min−1 under the protection of
nitrogen. Fourier transform infrared spectroscopy (FT-IR)
spectra were measured by a JASCO FT/IR-420 spectrometer
and the temperature was controlled by ES100P digital
4CC-y Yellow plate recrystallized with acetone
4CC-o Orange plate recrystallized with acetone
5CC-o Orange needle recrystallized with dichloromethane
and hexane
Conflicts of interest
There are no conflicts to declare.
controller. The samples were hold at a temperature for 2 min Acknowledgements
before measurement.
Z. Z. and Q. Y. acknowledge the scholarship of Chinese
Scholarship Committee for the support. A part of this work
(X-ray single crystallographic analysis) was supported by
Synthesis
The Schiff base compounds were prepared by the by
condensation of 4-chlorosalicyl- or 5-chlorosalicylaldehyde (2
mmol) and 4-chloroaniline (2 mmol) in methanol. The
products were characterized by elemental analysis, FAB MS
spectrometry, IR, and 1H and 13C NMR spectroscopy. The
NMR data were acquired for samples in chloroform-d, using
a JEOL ECS-400 spectrometer (400 MHz for H). All chemicals
were purchased from Tokyo Chemical Industry Co., Ltd. and
used without further purification.
Nanotechnology-Platform-Project by the Ministry
of
Education, Culture, Sports, Science and Technology Japan,
Grant Number JPMXP09A19UT0047.
Notes and references
1
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1
[M]+ found 265.1; H NMR (CDCl3) δ 6.93 (dd, ArH, 1H), 7.04
(d, ArH, 1H), 7.22 (m, ArH, 2H), 7.32 (d, ArH, 1H), 7.40 (m,
ArH, 2H), 8.27 (s, –NCH–, 1H), 13.34 (br, OH, 1H), 13C
NMR (CDCl3) δ 117.76, 117.79, 119.93, 122.59, 129.77, 132.95,
133.30, 139.41, 146.69, 161.98, 162.03.
5CC. To a solution of 5-chlorosalicylaldehyde (0.785 g, 5.0
mmol) dissolved in 20 ml methanol, 4-chloroaniline (0.639 g,
5.0 mmol) was added. After 24 hours, the reaction solution
were filtrated and yellow crystals were obtained (1.189 g, 89%).
FAB-MS m/z 265.0 calcd. For [M]+ found 265.2; 1H NMR
(CDCl3) 6.98 (d ArH, 1H), 7.22 (m, ArH, 2H), 7.33 (dd,
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