74
L. Jin et al. / Journal of Molecular Structure 1197 (2019) 73e79
2
. Experimental section
1556, (Ar, C]C), 1210, 1145 (C-O-C). Exact mass for DCT: 332.1307,
þ
þ
þ
ESI - MS (positive mode) [ DCT þ H
]
(m/z, 333.6915), [ DCT þ Na
(m/z, 356.0378). Elemental analysis (calcd. %) for C16
.2CH CH OH: C, 57.66; H, 6.25; N, 16.40; Found: C, 57.62; H, 6.02,
N, 6.25. H NMR (400 MHz, DMSO) d 11.07 (s, 1H), 9.49 (s, 1H), 8.19
þ
2.1. Materials preparation
]
20 4 2 ·
H N O S
0
3
2
1
All the solvents and chemicals were of analytic grade. The cat-
ions (such as KCl, NaCl, CaCl
anions (such as KBr, NaCl, KI, Na
NaHCO , NaNO , NaBr, Na $H O) were obtained from Shanghai
Experiment Reagent Co, Ltd (Shanghai, China). Other reagents were
gained from Shanghai. The probe DCT was prepared in DMSO to
obtain the stock solutions (1.0 mmol/L). The salts stock solutions
were newly prepared by distilled water. NaClO was prepared from
dilution of 10% solution in water.
2
, MgCl
2
$6H
2
O, and so on) and the
(s, 1H), 7.87 (s, 1H), 7.66 (s, 1H), 7.51 (d, J ¼ 8.8 Hz, 1H), 6.20 (dd,
2
SO
4
, Na
3
PO , NaH PO , NaOH,
4
2
4
J ¼ 8.9, 2.3 Hz, 1H), 6.09 (d, J ¼ 2.4 Hz, 1H), 3.32 (q, J ¼ 7.1 Hz, 6H),
1
3
3
3
2
C
2
O
4
2
1.09 (t, J ¼ 7.0 Hz, 7H). C NMR (101 MHz, DMSO)
d 177.18, 176.39,
158.70, 150.76, 142.83, 129.79, 107.71, 104.25, 97.95, 44.29, 12.94.
3. Results and discussion
þ
3
.1. UV-vis absorption and fluorescence spectra of DCT towards Al3
2
.2. Techniques and instruments
The recognization behavior of probe DCT were studied in a
CH OH - H O (6 : 4, v/v) system by spectroscopics. A solution of
CH
3
2
2
Bruker DRX 400 spectrometer with TMS as the internal standard
DCT (8.0
m
M) was placed in a quartz cell (10.0 mm width) and 2
m
L
1
13
was used to obtain the H NMR and C NMR spectra. NICOLET380
FT-IR spectrometer in KBr disks with the scanning speed
0
4
Elemental analyses (EAs). A Triple TOF TM 5600 system with the
positive ion model was used to obtain Electrospray ionization mass
spectra (ESI - MS). All of the fluorescence spectral were recorded on
a RF-5301 fluorescence spectrophotometer. UV-1800 ENG was
applied to proceed the Ultraviolet spectrum. A confocal laser
scanning microscope with model LSM-880 was used to fluores-
cence images on HepG2 cells.
3þ
ꢁ3
Al
(3 ꢀ 10 M) was drop-wised gradually, then the UV-vis
3þ
spectra titration for Al was obtained. As shown in Fig. 1, the ab-
sorption intensity at 402 nm was gradually decreased while the
absorption intensity at 368 nm was increased with the increase of
.6329 cm/s was applied to recorded the FT-IR spectra (4000 -
ꢁ1
00 cm ). VARI-EL elemental analyzer was used for recording
þ
3þ
Al . An isoabsorptive point at 382 nm was found. These results
3þ
revealed that a new product was generated between DCT and Al
[
42].
The changes of fluorescence emission spectra of DCT (1.0
m
M)
OH - H
6 : 4, v/v) were listed in Fig. 2. A drastic fluorescence enhancement
3þ
with the absence or presence of Al (0e16
mM) in CH
3
CH
2
2
O
(
3þ
was exhibited with the increase of Al . A new fluorescence peak at
4
28 nm was appeared. A fluorescence enhancement factor (FEF) is
2
2
.3. Synthesis of DCT
3þ
up to 15 - fold in the presence of 16 equiv. Al . Interestingly, the
Al induced the fluorescence turn on for DCT with a color changed
from colorless to blue under illumination with a 365 nm lamp
3
þ
.3.1. Synthesis of 3-acetyl-7-diethylaminocoumarin(DC)
3
-Acetyl-7-diethylaminocoumarin (DC) and 3-acetyl-7-
(showed in Fig. 2 inset).
diethylaminocoumarinthiosemicarbazone (DCT) were synthesized
according the reported methods [39e41], as shown in Scheme 1.
Briefly, 0.966 g (5 mmol) of 4-(Diethylamino)salicylaldehyde and
0
.646 g (5 mmol) of ethyl acetoacetate were added to 30 mL
CH CH OH. Then drop-wise of morpholine and acetic acid into the
3
2
above solution. After refluxed for 20 h with stirring constantly, the
color was changed to dark green, then stop the reaction and cooled
to room temperature, the yellow products was got. The products
was collected and washed by CH
yield of 39.4% for DC. FT-IR (KBr, cm ): 3018(Ar - H), 2982 (C - H),
3 2
CH OH and dried in vacuo with
ꢁ1
1
752 (C ¼ O), 1644, 1608 (Ar, C]C), 1236, 1182 (C-O-C). Exact mass
þ
þ
for DC: 259.1208, ESI - MS (positive mode) [ DC þ Na
]
(m/
z,282.5092). Elemental analysis (calcd. %) for C15H17NO : C, 69.48;
3
H, 6.61; N. 5.41; Found: C, 69.56; H, 5.94; N. 5.39.
2
.3.2. Synthesis of 3-acetyl-7-
diethylaminocoumarinthiosemicarbazone(DCT)
DCT was prepared by mixing of DC with thiosemicarbazide in
0 mL absolute CH CH OH. Then drop-wise a few of CH COOH into
3
3
2
3
the above solution and the resulting solution was reflux for 12 h.
After ended the reaction, the dark brown color product was ob-
tained and recrystallized by CH
3
CH
2
OH. Dried in vacuum desic-
3þ
3 2
mM) with AI (0e40 mM) in CH CH OH -
Fig. 1. Absorption titration of probe DCT (10
O (6 : 4, v/v) at room temperature.
ꢁ
1
cator. FT-IR (KBr, cm ): 3461 (N-H), 2982 (C - H),1732 (C ¼ O),1611,
H
2
Scheme 1. Synthesis of probe DCT.