2
G.-F. Bian et al. / Journal of Molecular Structure 1111 (2016) 1e8
i: Salicylamide, SOCl2, xylene, pyridine; ii: methanol, (3-(trifluoromethyl)phenyl)hydrazine
Scheme 1. Synthesis of CCN1-CF3.
2.3. Synthesis of 2-(2-hydroxyphenyl)-4H-benzo[e] [1,3]oxazin-4-
one(CC) [22]
Salicylic acid (2 g, 14.5 mmol), salicylamide (1.53 g, 11.1 mmol)
and pyridine (1 ml) were refluxed in xylene (20 mL). Thionyl
chloride (1.9 g, 16.0 mmol) was added with vigorous stirring over a
period of 4 h. An intense evolution of SO2 and HCl was noted. At the
end of the reaction, the product started to crystallize. Stirring was
continued for an additional 30 min, and the xylene was removed by
reduced-pressure distillation. The resulting solid residue was sus-
pended in EtOH (30 mL) and acetic acid (1 mL). The mixture was
heated gently and then allowed to cool to 20 ꢀC. The precipitate was
filtered and recrystallized from 2-methoxyethanol (35 mL). Yield:
yellow-green solid (1.04 g, 4.34 mmol, 39%). m.p. 202.2e204.6 ꢀC.
2. Experimental
2.1. Material and general methods
All reagents were obtained from commercial suppliers and used
without further purification unless otherwise indicated. Glassware
was dried in an oven at 100 ꢀC and cooled under a stream of inert
gas before use. The 1H NMR and 13C NMR spectra were recorded on
a Bruker AVANCE III 500 MHz instrument (Bruker, Switzerland)
using dimethyl sulfoxide-d6(DMSO-d6) as the solvent. Mass spec-
troscopy was carried out with a Thermo LCQ Fleet MS spectrometer.
The UVevis absorption spectrum was recorded on a Perkin Elmer
Lambda 35 spectrophotometer. Fluorescent measurements were
recorded on a PerkineElmer LS-55 luminescence spectrophotom-
eter. ESI-MS spectra were obtained with an Agilent 6210 time-of-
flight (TOF) mass spectrometer. All the solvents employed for the
spectroscopic measurements were of UV spectroscopic grade
(Aldrich). Dilute solutions with absorbance of less than 0.05 at the
excitation wavelength were used for the measurement of fluores-
cence quantum yields. 9,10-Diphenylanthracene was used as the
1H NMR (500 MHz, DMSO-d6)
d12.95 (s, 1H), 8.25e8.21 (m, 1H),
8.08 (dd, J1 ¼ 7.8, J2 ¼ 1.5 Hz, 1H), 7.98e7.94 (m, 1H), 7.81 (dd,
J1 ¼ 8.4, J2 ¼ 0.6 Hz, 1H), 7.68e7.60 (m, 2H), 7.13e7.08 (m, 2H). ESI-
MS: m/z. Calculated for
[MþH] ¼ 240.0655.
C
14H9NO3
¼
239.06; found
2.4. Synthesis of 2,20-(1-(3-(trifluoromethyl)phenyl)-1H-1,2,4-
triazole-3,5-diyl) diphenol (CCN1-CF3)
A mixture of CC (100 mg, 0.4 mmol) and (3-(trifluoromethyl)
phenyl)hydrazine (79 mg, 0.4 mmol) in anhydrous methanol
(20 mL) was heated at 65 ꢀC for 2 h, and then cooled to 15 ꢀC. Filter
the cooling liquid. Reddish brown crystals were collected in a yield
of 90%. (150 mg, 0.4 mmol). m.p. 242.1e244.6 ꢀC. 1H NMR
(500 MHz, DMSO-d6)
d10.78 (s, 1H), 10.10 (s, 1H), 8.07 (dd,
standard (FF ¼ 0.90 in cyclohexane) [21]. The quantum yield,
F
, was
J1 ¼ 7.8 Hz, J2 ¼ 1.5 Hz, 1H), 7.80 (dd, J1 ¼ 11.6 Hz, J2 ¼ 7.0 Hz, 3H),
7.74e7.68 (m, 1H), 7.57 (dd, J1 ¼ 7.6 Hz, J2 ¼ 1.5 Hz, 1H), 7.43e7.34
(m, 2H), 7.07e6.96 (m, 3H), 6.88 (d, J ¼ 8.2 Hz, 1H). 13C NMR
calculated using equation (1):
ꢀ
ꢁꢀ
ꢁ
2
I sample A std
I std A sample
n sample
n std
(100 MHz, DMSO) d(ppm) 160.39, 156.81, 155.60, 152.63, 138.89,
Fsample ¼ Fstd
(1)
2
133.07, 131.94, 131.60, 131.07, 130.285(q, JC-F ¼ 32.6 Hz), 127.86,
3
127.32, 125.63(q, JC-F ¼ 3.7 Hz), 124.14(q, 1JC-F ¼ 272.3 Hz), 120.57
3
(q, JC-F ¼ 3.9 Hz), 120.15, 119.92, 117.54, 116.53, 114.66, 114.14. 19
F
where the sample and std subscripts denote the sample and stan-
dard, respectively, I is the integrated emission intensity, A stands for
the absorbance, and n is refractive index.
NMR (376.5 MHz, DMSO)
for C21H14F3N3O2 ¼ 397.10; found [MþH] ¼ 398.1111.
d
(ppm) ꢂ61.388. ESI-MS: m/z. Calculated
3. Results and discussions
2.2. Preparation of fluorometric and UV/Vis titration solutions
3.1. X-ray structure determination
As shown in Scheme 1, the stock solution of CCN1-CF3
(1.0 ꢁ 10ꢂ3 M) was prepared in CH3OH. The concentration of CCN1-
CF3 in the fluorescence titration was 1 ꢁ 10ꢂ5 M with CH3OH and
mixed solvent medium (CH3OH/H2O ¼ 9/1, v/v) as solvents. During
titration, metal ion solution was added into a solution of CCN1-CF3
(10 mL) and the whole volume of the final system can be considered
as 10 mL because the volume of metal ion solution added is
negligible compared to that of CCN1-CF3. After stirring, the fluo-
rescence spectra was collected. For all measurements, excitation
and emission slit widths were 2 nm.
The single crystal structure was confirmed by X-ray diffraction
analysis. Crystals of CCN1-CF3 suitable for X-ray structural analysis
were grown by slow evaporation of the CCN1-CF3 dichloro-
methane/ethanol solution. Compound CCN1-CF3 crystallized in the
triclinic space group P-1, with
a
¼ 11.270(2), b ¼ 12.211(4),
c ¼ 15.365(5) Å,
a
¼ 87.01(3)ꢀ,
b
¼ 72.84(2)ꢀ,
g
¼ 64.38(3)ꢀ. Fig. 1
shown the Single-crystal structure of CCN1-CF3. There existed an
intramolecular H-bond between the nitrogen atoms and the proton
of neighboring phenolate group in short distances of 1.848, 1.938
and1.906 Å, forming a six membered ring through hydrogen