Synthesis and spectroscopic properties of novel fluorescent compounds containing bis-pyrazole ring

Article abstract of DOI:10.1007/s10895-014-1395-y

A series of pyrazoline derivatives containing pyrazole group were synthesized and characterized by means of ¹H NMR, FT-IR, MS and elemental analysis, and their UV-vis absorption behavior and fluorescent properties were also measured. Moreover, the influence of metal ions on spectral properties of synthetic products was examined with compound A ₅ as an example. It has been found that all synthetic pyrazoline derivatives show two remarkable absorption peaks at about 260 and 360 nm and the maximum emission peak at 445-467 nm. Especially, the joined of Co²⁺ can quench the fluorescence of compound A ₅ obviously.

Full text of DOI:10.1007/s10895-014-1395-y

J Fluoresc
DOI 10.1007/s10895-014-1395-y
ORIGINAL PAPER
Synthesis and Spectroscopic Properties of Novel Fluorescent
Compounds Containing Bis-pyrazole Ring
Tiegang Ren & Jie Wang & Guihui Li & Yongzhe Li
Received: 14 February 2014 /Accepted: 7 April 2014
#
Springer Science+Business Media New York 2014
Abstract A series of pyrazoline derivatives containing
pyrazole group were synthesized and characterized by means
of 1H NMR, FT-IR, MS and elemental analysis, and their UV–
vis absorption behavior and fluorescent properties were also
measured. Moreover, the influence of metal ions on spectral
properties of synthetic products was examined with com-
pound A5 as an example. It has been found that all synthetic
pyrazoline derivatives show two remarkable absorption peaks
at about 260 and 360 nm and the maximum emission peak at
445–467 nm. Especially, the joined of Co2+ can quench the
fluorescence of compound A5 obviously.
dihydro-(1H)-pyrazole derivatives to amine oxidases activity;
Ozdemir [8] have synthesized some 1-(4-phenyl-2-thiazolyl)-
3-(2- thiophene)-5-aryl-2-pyrazoline derivatives and found
that these compounds show strong antibacterial activity to
escherichelloa, staphylococcus and salmonella. At the same
time these compounds have been widely used as fluorescer
[9], fluorescent probe [10], dyestuff [11] and electrolumines-
cent materials [12, 13] etc.
The selective recognition of metal ion is of great signifi-
cance in environment, chemistry, life science and medicine.
As a kind of widely used organic fluorescent compounds, the
excellent photoelectric properties and high fluorescence quan-
tum yield of pyrazoline derivatives add to their wide use in the
selective recognition of metal ion. Shi et al. [14] had found
that the fluorescence recognition with 1 - (2 - benzothiazole) -
3 - (2 - thiophene) - 2 - pyrazoline to Zn2 + had good sensitivity
and selectivity; Xu et al. [15] studied the selective recognition
of 1,5-diaryl-3-(2- hydroxyl-4,6-dimethoxylphenyl)-2-
pyrazolines to Cu2+. Thus in the present research we adopt a
simple procedure to synthesize bis-pyrazole ring compounds
with chalcone and substituted phenylhydrazine hydrochloride
as the starting materials, then their spectroscopic properties
and fluorescence quenching behavior to different metal ions
are researched.
.
.
Keywords Pyrazoline derivative Pyrazole group
2+
.
.
.
Synthesis Ion recognition Pectroscopic properties Co
Introduction
As a kind of important nitrogen heterocyclic compound,
pyrazoline derivatives possess particular physicochemical
property and biological activities. These compounds have
been applied in biology [1], medicine [2], pesticide [3–5]
and photoelectric material [6] area. Mnna F [7] have
studied the inhibiting ability of 1-acetyl-3,5-diphenyl-4,5-
Electronic supplementary material The online version of this article
(doi:10.1007/s10895-014-1395-y) contains supplementary material,
which is available to authorized users.
Experiments
:
:
T. Ren J. Wang Y. Li
Physical Measurement and Materials
Fine Chemistry and Engineering Research Institute, College of
Chemistry and Chemical Engineering, Henan University,
Kaifeng 475004, People’s Republic of China
Mass spectra (MS) were measured in an Agilent 1100LC-MS
mass spectrometer. Infrared (IR) spectra of target prod-
ucts within 400–4,000 cm−1 were determined with a
AVATAR360 type Fourier transform infrared spectrometer
(KBr). 1H NMR spectra in CDCl3 solvent were recorded with
an AVANCE-400 type pulse Fourier transform nuclear
G. Li (*)
Key Laboratory of Ministry of Education for Special Functional
Materials, Henan University, Kaifeng 475004, People’s Republic of
China
e-mail: rtg@henu.edu.cn

J Fluoresc
magnetic resonance (NMR) spectrometer, and TMS as inter-
nal standard. A PE2400 elemental analysis apparatus have
been used to elemental analysis. UV–vis absorption spectra
of synthetic compounds were recorded with a Hitachi U-4,100
spectrophotometer in a wavelength range of 200–800 nm
(to-be-tested compounds were separately dissolved in spec-
tral grade dimethylfomamide (DMF) at a concentration of
5.0×10−5 mol/L). The fluorescence spectra of various syn-
thetic compounds separately dissolved in spectral grade DMF
at a concentration of 5.0×10−5 mol/L were recorded with a
Hitachi F-7,000 spectrofluorometer in right angle detection
mode (each solution was excited at λmax and the corrected
fluorescence emission spectrum was recorded also at a wave-
length of 200–800 nm). Specifically, synthetic target com-
pound A5 was dissolved in spectral grade DMF at a concen-
tration of 5.0×10−5 mol/L while the twelve different kinds of
metal ions (Cu2+, Zn2+, Co2+, Fe3+, Ca2+, Na+, Pb2+, Sn2+,
In3+, Mn2+ ,Cd2+, Mg2+) were joined into A5 at molar ratio 2:1
(concentration of 2.5×10−5 mol/L for M+), respectively, so as
to explore the influence of metal ions on the spectroscopic
properties of synthetic products.
3.79(dd, 1H, J=16.7, 11.8Hz, pyrazoline-H), 5.31(dd, 1H,
J=11.9, 7.1Hz, pyrazoline-H), 7.02–7.10(m, 3H, Ar-H),
7.27–7.35(m, 2H, Ar-H), 7.38–7.48(m, 5H, Ar-H), 7.58–
7.61(m, 2H, Ar-H), 7.68–7.75(m, 3H, Ar-H), 7.80(s,
1H, Ar-H). IR(KBr, cm−1) ν: 3031(Ar-H), 2920(CH2),
1602(PyrazolineC=N), 1512, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 79.34; H, 5.86; N, 14.80. Found: C, 79.39; H, 5.81;
N, 14.83.
4-(1-(3,4-dimethylphenyl)-3-phenyl-4,5-dihydro-1H-
pyrazol-5-yl)-1-phenyl-1H-pyrazole (A3). Light yellow solid
0.20 g,yield 51 %.APCI-MS (m/z, M+): 393.6. 1H
NMR(CDCl3) δ: 2.16(s, 3H, CH3), 2.22(s, 3H, CH3),
3.20(dd, 1H, J=16.7, 7.1Hz, pyrazoline-H), 3.79(dd, 1H,
J=16.7, 11.9Hz, pyrazoline-H), 5.31(dd, 1H, J=11.7,
7.0Hz, pyrazoline-H), 6.82–6.86(m, 1H, Ar-H), 6.95–
7.00(m, 1H, Ar-H), 7.27–7.36(m, 2H, Ar-H), 7.39(d, 3H,
J=7.4Hz, Ar-H), 7.41–7.47(m, 2H, Ar-H), 7.60(m, 2H,
Ar-H), 7.70–7.76(m, 3H, Ar-H), 7.80(s, 1H, Ar-H).
I R ( K B r, c m − 1 ) ν : 3 0 2 5 ( A r - H ) , 2 9 2 1 ( C H 2 ) ,
1601(PyrazolineC=N), 1507, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 79.56; H, 6.16; N, 14.27. Found: C, 79.52; H, 6.11;
N, 14.31.
All chemicals and solvents are of commercial reagent grade
and used without further purification. A series of chalcone
compounds were synthesized referencing to literature [16].
4-(1-(4-fluorophenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-
5-yl)-1-phenyl-1H-pyrazole (A4). Yellow solid 0.21 g,yield
1
55 %.APCI-MS (m/z, M+): 383.6. H NMR(CDCl3) δ:
General Procedure for the Preparation
of 4-(1-aryl-3-phenyl-4,5-dihydro- 1H-pyrazol-5- yl)-1-
aryl-1H-pyrazole
3.23(dd, 1H, J=16.7, 7.2Hz, pyrazoline-H), 3.81(dd, 1H,
J=16.8, 11.8Hz, pyrazoline-H), 5.29(dd, 1H, J =11.7,
7.2Hz, pyrazoline-H), 6.91–6.96(m, 2H, Ar-H), 7.09–
7.13(m, 2H, Ar-H), 7.28–7.37(m, 2H, Ar-H), 7.39–
7.49(m, 4H, Ar-H), 7.59–7.62(m, 2H, Ar-H), 7.69–
7.75(m, 3H, Ar-H), 7.80(s, 1H, Ar-H). IR(KBr, cm−1)
ν: 3031(Ar-H), 2919(CH2), 1608(PyrazolineC=N), 1512,
1477(C=C), 1243(C-N). Anal. Calc.: C, 75.37; H, 5.01;
N, 14.65. Found: C, 75.32; H, 5.04; N, 14.61.
1 mmol chalcone compound and 1.2 mmol phenylhydrazine
(or 1 mmol substituted phenylhydrazine hydrochloride) were
dissolved in 20 mL ethanol, 0.8 mL 0.8 mol/L HCl was added,
stirred and heated refluxing 6 h. The mixture was cooled and
left at room temperature overnight. 35 % K2CO3 solution was
added and the mixture was adjusted to neutral, followed by
filtered, dried, and the crude mixture was purified by column
chromatography (silica gel, cyclohexane/ethyl acetate).
4-(1,3-diphenyl-4,5-dihydro-1H-pyrazol-5-yl)-1-phenyl-
1H-pyrazole(A1). Light yellow solid 0.12 g,yield 33 %.APCI-
4-(1-(4-bromophenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-
5-yl)-1-phenyl-1H-pyrazole (A5). Yellow solid 0.25 g,yield
1
56 %.APCI-MS (m/z, M+): 444.3. H NMR(CDCl3) δ:
3.24(dd, 1H, J=16.7, 6.4Hz, pyrazoline-H), 3.82(dd, 1H,
J =16.8, 12.0Hz, pyrazoline-H), 5.34(dd, 1H, J=11.7,
6.7Hz, pyrazoline-H), 7.04(d, 2H, J=9.0Hz, Ar-H),
7.30(t, 3H, J=6.3Hz, Ar-H), 7.39–7.51(m, 5H, Ar-H),
7.59–7.63 (m, 2H, Ar-H), 7.68–7.75(m, 3H, Ar-H), 7.77(s,
1H, Ar-H). IR(KBr, cm−1) ν: 3031(Ar-H), 2922(CH2),
1608(Pyrazoline C=N), 1512, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 65.02; H, 4.32; N, 12.64. Found: C, 65.05; H, 4.36;
N, 12.60.
4-(1,3-diphenyl-4,5-dihydro-1H-pyrazol-5-yl)-1-p-tolyl-
1H-pyrazole (B1). Light yellow solid 0.11 g,yield 29 %.APCI-
MS (m/z, M+): 379.2. 1H NMR(CDCl3) δ: 1.95(s, 3H, CH3),
3.24(dd, 1H, J=16.7, 6.8Hz, pyrazoline-H), 3.82(dd, 1H,
J=17.0, 11.8Hz, pyrazoline-H), 5.37(dd, 1H, J=11.8,
6.4Hz, pyrazoline-H), 6.81–6.89(m, 1H, Ar-H), 7.17–
7.25(m, 3H, Ar-H), 7.31–7.46(m, 5H, Ar-H), 7.52–
1
MS (m/z, M+): 365.2. H NMR(CDCl3) δ: 3.24(dd, 1H,
J=16.8, 6.8Hz, pyrazoline-H), 3.82(dd, 1H, J=16.8,
11.9Hz, pyrazoline-H), 5.37(dd, 1H, J=11.9, 6.7Hz,
pyrazoline-H), 6.85(dd, 1H, J=14.3, 7.3Hz, Ar-H),
7.18–7.25(m, 5H, Ar-H), 7.30–7.42(m, 3H, Ar-H),
7.43–7.66(m, 5H, Ar-H), 7.68–7.79(m, 3H, Ar-H).
I R ( K B r, c m − 1 ) ν : 3 0 5 4 ( A r - H ) , 2 9 2 4 ( C H 2 ) ,
1597(PyrazolineC=N), 1503,1477(C=C), 1243(C-N). Anal.
Calc.: C, 79.10; H, 5.53; N, 15.37. Found: C, 79.02; H,
5.61; N, 15.31.
1-phenyl-4-(3-phenyl-1-p-tolyl-4,5-dihydro-1H-pyrazol-5-
yl)-1H-pyrazole(A2). Light yellow solid 0.29 g,yield
1
77 %.APCI-MS (m/z, M+): 379.6. H NMR(CDCl3) δ:
2.25(s, 3H, CH3), 3.21(dd, 1H, J=16.7, 7.1Hz, pyrazoline-H),

J Fluoresc
7.66(m, 4H, Ar-H), 7.71–7.76(m, 3H, Ar-H). IR(KBr, cm−1)
ν: 3056(Ar-H), 2920(CH2), 1596(PyrazolineC=N), 1503,
1477(C=C), 1243(C-N). Anal. Calc.: C, 79.34; H, 5.86; N,
14.80. Found: C, 79.30; H, 5.89; N, 14.75.
1477(C=C), 1243(C-N). Anal. Calc.: C, 65.65; H, 4.63; N,
12.25. Found: C, 65.60; H, 4.67; N, 12.21.
1-(3,4-dimethylphenyl)-4-(1,3-diphenyl-4,5-dihydro-1H-
pyrazol-5-yl)-1H-pyrazole (C1). Light yellow solid
0.14 g,yield 36 %.APCI-MS (m/z, M+): 393.2. 1H
NMR(CDCl3) δ: 2.25(s, 3H, CH3), 2.28(s, 3H, CH3),
3.23(dd, 1H, J=16.8, 6.7Hz, pyrazoline-H), 3.81(dd, 1H,
J=16.8, 11.9Hz, pyrazoline-H), 5.35(dd, 1H, J=11.9, 6.7Hz,
pyrazoline-H), 6.81–6.83(m, 1H, Ar-H), 7.13–7.25(m, 5H,
Ar-H), 7.28–7.36(m, 2H, Ar-H), 7.38–7.53(m, 4H, Ar-H),
7.68(s, 1H, Ar-H), 7.74–7.76(m, 3H, Ar-H). IR(KBr, cm−1)
ν: 3051(Ar-H), 2918(CH2), 1595(PyrazolineC=N), 1505,
1477(C=C), 1243(C-N). Anal. Calc.: C, 79.56; H, 6.16; N,
14.27. Found: C, 79.59; H, 6.18; N, 14.25.
4-(3-phenyl-1-p-tolyl-4,5-dihydro-1H-pyrazol-5-yl)-1-p-
tolyl-1H-pyrazole (B2). Yellow solid 0.11 g,yield 28 %.APCI-
MS (m/z, M+):393.2. 1H NMR(CDCl3) δ: 2.25(s, 3H, CH3),
2.35(s, 3H, CH3), 3.21(dd, 1H, J=16.7, 7.0Hz, pyrazoline-H),
3.79(dd, 1H, J=16.7, 11.8Hz, pyrazoline-H), 5.30(dd, 1H,
J=11.8, 7.2Hz, pyrazoline-H), 7.06(dd, 3H, J=22.5, 8.7Hz,
Ar-H), 7.20(t, 2H, J=9.5Hz, Ar-H), 7.28–7.43(m, 5H, Ar-H),
7.47(t, 2H, J=6.8Hz, Ar-H), 7.67(s, 1H, Ar-H), 7.73–7.75(m,
2H, Ar-H). IR(KBr, cm−1) ν: 3031(Ar-H), 2919(CH2),
1600(PyrazolineC=N), 1517, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 79.56; H, 6.16; N, 14.27. Found: C, 79.52; H, 6.11;
N, 14.21.
4-(1-(3,4-dimethylphenyl)-3-phenyl-4,5-dihydro-1H-
pyrazol-5-yl)-1-p-tolyl-1H-pyrazole (B3). Light yellow solid
0.15 g,yield 37 %.APCI-MS (m/z, M++Na):429.5. 1H
NMR(CDCl3) δ: 2.17(s, 3H, CH3), 2.23(s, 3H, CH3), 2.35(s,
3H, CH3), 3.20(dd, 1H, J=16.7, 7.0Hz, pyrazoline-H),
3.78(dd, 1H, J=16.7, 11.8Hz, pyrazoline-H), 5.30(dd, 1H,
J=11.8, 7.0Hz, pyrazoline-H), 6.84(dd, 1H, J=8.2, 2.4Hz,
Ar-H), 6.97(d, 1H, J=8.2Hz, Ar-H), 7.09(d, 1H, J=2.1Hz,
Ar-H), 7.19(d, 2H, J=8.1Hz, Ar-H), 7.31–7.44(m, 3H, Ar-H),
7.46–7.49(m, 2H, Ar-H), 7.68(s, 1H, Ar-H), 7.74–7.76(m,
3H, Ar-H). IR(KBr, cm−1) ν: 3025(Ar-H), 2918(CH2),
1612(PyrazolineC=N), 1512, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 79.77; H, 6.45; N, 13.78. Found: C, 79.72; H, 6.48;
N, 13.72.
4-(1-(4-fluorophenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-
5-yl)-1-p-tolyl-1H-pyrazole (B4). Light yellow solid
0.19 g,yield 48 %.APCI-MS (m/z, M+): 397.4. 1H
NMR(CDCl3) δ: 2.35(s, 3H, CH3), 3.23(dd, 1H, J=16.8,
7.2Hz, pyrazoline-H), 3.79(dd, 1H, J=16.8, 11.8Hz,
pyrazoline-H), 5.28(dd, 1H, J=11.8, 7.2Hz, pyrazoline-H),
6.81–6.95(m, 2H, Ar-H), 7.10–7.13(m, 1H, Ar-H), 7.17–
7.25(m, 3H, Ar-H), 7.33–7.44(m, 3H, Ar-H), 7.46–7.55(m,
2H, Ar-H), 7.67(s, 1H, Ar-H), 7.72–7.75(m, 3H, Ar-H).
I R ( K B r, c m − 1 ) ν : 3 0 3 1 ( A r - H ) , 2 9 2 0 ( C H 2 ) ,
1617(PyrazolineC=N), 1512, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 75.74; H, 5.34; N, 14.13. Found: C, 75.70; H, 5.39;
N, 14.11.
4-(1-(4-bromophenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-
5-yl)-1-p-tolyl-1H-pyrazole (B5). Light yellow solid
0.19 g,yield 42 %.APCI-MS (m/z, M+): 458.9. 1H
NMR(CDCl3) δ: 2.35(s, 3H, CH3), 3.24(m, 1H, J=16.9,
6.4Hz, pyrazoline-H), 3.81(dd, 1H, J=16.9, 11.8Hz,
pyrazoline-H), 5.33(dd, 1H, J=11.8, 6.4Hz, pyrazoline-H),
7.02–7.06(m, 2H, Ar-H), 7.20(d, 2H, J=8.2Hz, Ar-H),
7.27–7.44(m, 5H, Ar-H), 7.46–7.54(m, 2H, Ar-H), 7.65(s,
1H, Ar-H), 7.72–7.75(m, 3H, Ar-H). IR(KBr, cm−1) ν:
3031(Ar-H), 2922(CH2), 1613(PyrazolineC=N), 1519,
1-(3,4-dimethylphenyl)-4-(3-phenyl-1-p-tolyl-4,5-
dihydro-1H-pyrazol-5-yl)-1H-pyrazole (C2). Light yellow
1
solid 0.17 g,yield 42 %.APCI-MS (m/z, M+):407.6. H
NMR(CDCl3) δ: 2.25(s, 6H, CH3), 2.28(s, 3H, CH3),
3.21(dd, 1H, J=16.7, 7.2Hz, pyrazoline-H), 3.79(dd, 1H,
J =16.7, 11.9Hz, pyrazoline-H), 5.30(dd, 1H, J=11.8,
7.2Hz, pyrazoline-H), 7.02–7.19(m, 5H, Ar-H), 7.28–7.35(m,
2H, Ar-H), 7.38–7.43(m, 3H, Ar-H), 7.67(s, 1H, Ar-H), 7.73–
7.75(m, 3H, Ar-H). IR(KBr, cm−1) ν: 3025(Ar-H), 2919(CH2),
1613(PyrazolineC=N), 1515, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 79.77; H, 6.45; N, 13.78. Found: C, 79.78; H, 6.43;
N, 13.76.
1-(3,4-dimethylphenyl)-4-(1-(3,4-dimethylphenyl)-3-phe-
nyl-4,5-dihydro-1H-pyrazol-5-yl)-1H-pyrazole (C3).Light
yellow solid 0.17 g,yield 40 %.APCI-MS (m/z, M+):421.5.
1H NMR(CDCl3) δ: 2.17(s, 3H, CH3), 2.23(s, 3H, CH3),
2.26(s, 3H, CH3), 2.29(s, 3H, CH3), 3.21(dd, 1H, J=16.7,
7.1Hz, pyrazoline-H), 3.79(dd, 1H, J=16.8, 11.9Hz,
pyrazoline-H), 5.31(dd, 1H, J=11.9, 7.0Hz, pyrazoline-H),
6.83–6.86(m, 1H, Ar-H), 6.97(d, 1H, J=8.3Hz, Ar-H),
7.09–7.20(m, 2H, Ar-H), 7.29–7.35(m, 2H, Ar-H), 7.39–
7.45(m, 3H, Ar-H), 7.68(s, 1H, Ar-H), 7.74–7.76(m, 3H,
Ar-H). IR(KBr, cm−1) ν: 3031(Ar-H), 2919(CH2),
1612(PyrazolineC=N), 1506, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 79.97; H, 6.71; N, 13.32. Found: C, 79.92; H, 6.74;
N, 13.27.
1-(3,4-dimethylphenyl)-4-(1-(4-fluorophenyl)-3-phenyl-
4,5-dihydro-1H-pyrazol-5-yl)-1H- pyrazole (C4). Yellow sol-
id 0.15 g,yield 37 %.APCI-MS (m/z, M)+:411.5. 1H
NMR(CDCl3) δ: 2.26(s, 3H, CH3), 2.28(s, 3H, CH3),
3.23(dd, 1H, J=16.8, 7.3Hz, pyrazoline-H), 3.80(dd, 1H,
J=16.8, 11.7Hz, pyrazoline-H), 5.27(dd, 1H, J=11.7,
7.2Hz, pyrazoline-H), 6.90–6.95(m, 2H, Ar-H), 7.10–
7.16(m, 2H, Ar-H), 7.28–7.36(m, 2H, Ar-H), 7.39–7.44(m,
3H, Ar-H), 7.49–7.53(m, 1H,Ar-H), 7.66(s, 1H, Ar-H), 7.73–
7.75(m, 3H, Ar-H). IR(KBr, cm−1) ν: 3031(Ar-H),
2924(CH2), 1613(PyrazolineC=N), 1509, 1477(C=C),
1243(C-N). Anal. Calc.: C, 76.08; H, 5.65; N, 13.65. Found:
C, 76.02; H, 5.68; N, 13.70.

J Fluoresc
4-(1-(4-bromophenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-
5-yl)-1-(3,4-dimethylphenyl)-1H-pyrazole (C5). Yellow solid
0.12 g,yield 25 %.APCI-MS (m/z, M+):472.4. 1H
NMR(CDCl3) δ: 2.27(s, 3H, CH3), 2.29(s, 3H, CH3),
3.25(dd, 1H, J=16.8, 6.4Hz, pyrazoline-H), 3.82(dd, 1H,
J=16.8, 11.8Hz, pyrazoline-H), 5.34(dd, 1H, J=11.7,
6.5Hz, pyrazoline-H), 7.03–7.07(m, 2H, Ar-H), 7.16(d,
1H, J=8.2Hz, Ar-H), 7.29–7.32(m, 3H, Ar-H), 7.35–
7.43(m, 4H, Ar-H), 7.66(s, 1H, Ar-H), 7.73–7.76(m,
3H, Ar-H). IR(KBr, cm−1) ν: 3031(Ar-H), 2919(CH2),
1613(PyrazolineC=N), 1503,1477(C=C), 1243(C-N). Anal.
Calc.: C, 66.25; H, 4.92; N, 11.89. Found: C, 66.22; H, 4.95;
N, 11.90.
4-(1,3-diphenyl-4,5-dihydro-1H-pyrazol-5-yl)-1-(4-
fluorophenyl)-1H-pyrazole (D1). Light yellow solid
0.18 g,yield 47 %.APCI-MS (m/z,M++Na):405.2. 1H
NMR(CDCl3) δ: 3.22(dd, 1H, J=16.8, 6.5Hz, pyrazoline-
H), 3.81(dd, 1H, J=16.8, 11.9Hz, pyrazoline-H), 5.36(dd,
1H, J=11.8, 6.6Hz, pyrazoline-H), 6.82–6.86(m, 1H, Ar-H),
7.06–7.12(m, 2H, Ar-H), 7.17–7.24(m, 3H, Ar-H), 7.33–
7.42(m, 3H, Ar-H), 7.45–7.59(m, 3H, Ar-H), 7.69(s, 1H,
Ar-H), 7.72–7.76(m, 3H, Ar-H). IR(KBr, cm−1) ν: 3056(Ar-
H), 2929(CH2), 1597(PyrazolineC=N), 1503, 1477(C=C),
1243(C-N). Anal. Calc.: C, 75.37; H, 5.01; N, 14.65. Found:
C, 75.35; H, 5.05; N, 14.62.
1-(4-fluorophenyl)-4-(3-phenyl-1-p-tolyl-4,5-dihydro-1H-
pyrazol-5-yl)-1H-pyrazole (D2). Light yellow solid
0.17 g,yield 43 %.APCI-MS (m/z,M+): 397.3. 1H
NMR(CDCl3) δ: 2.25(s, 3H, CH3), 3.20(dd, 1H, J=16.7,
7.0Hz, pyrazoline-H), 3.79(dd, 1H, J=16.7, 11.8Hz,
pyrazoline-H), 5.31(dd, 1H, J=11.8, 7.0Hz, pyrazoline-H),
7.05–7.09(m, 4H, Ar-H), 7.27–7.36(m, 2H, Ar-H), 7.36–
7.47(m, 3H, Ar-H), 7.51–7.58(m, 3H, Ar-H), 7.68(s, 1H,
Ar-H), 7.71–7.75(m, 2H, Ar-H). IR(KBr, cm−1) ν: 3031(Ar-
H), 2921(CH2), 1616(PyrazolineC=N), 1516,1477(C=C),
1243(C-N). Anal. Calc.: C, 75.74; H, 5.34; N, 14.13. Found:
C, 75.76; H, 5.38; N, 14.10.
H), 3.81(dd, 1H, J=16.7, 11.8Hz, pyrazoline-H), 5.29(dd,
1H, J=11.6, 7.2Hz, pyrazoline-H), 6.93(d, 2H, J=8.7Hz,
Ar-H), 7.10(t, 4H, J=7.6Hz, Ar-H), 7.33–7.46(m, 3H, Ar-
H), 7.50–7.58(m, 2H, Ar-H), 7.68(s, 1H, Ar-H), 7.72–
7.77(m, 3H, Ar-H). IR(KBr, cm−1) ν: 3055(Ar-H),
2928(CH2), 1611(Pyrazoline C=N), 1512, 1477(C=C),
1243(C-N). Anal. Calc.: C, 71.99; H, 4.53; N, 13.99. Found:
C, 72.02; H, 4.58; N, 13.97.
4-(1-(4-bromophenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-
5-yl)-1-(4-fluorophenyl)-1H-pyrazole (D5). Yellow solid
0.12 g,yield 26 %.APCI-MS (m/z,M+): 462.7. 1H
NMR(CDCl3) δ: 3.23(dd, 1H, J =16.9, 6.3Hz, pyrazoline-
H), 3.82(dd, 1H, J=16.8, 11.8Hz, pyrazoline-H), 5.34(dd,
1H, J=11.8, 6.1Hz, pyrazoline-H), 7.03(d, 2H, J=9.0Hz,
Ar-H), 7.10(t, 2H, J=8.6Hz, Ar-H), 7.30(d, 2H, J=9.0Hz,
Ar-H), 7.34–7.423(m, 3H, Ar-H), 7.51–7.61(m, 2H, Ar-H),
7.66(s, 1H, Ar-H), 7.69–7.77(m, 3H, Ar-H). IR(KBr, cm−1) ν:
3056(Ar-H), 2929(CH2), 1597(PyrazolineC=N), 1515,
1477(C=C), 1243(C-N). Anal. Calc.: C, 62.48; H, 3.93; N,
12.14. Found: C, 62.45; H, 3.96; N, 12.12.
1-(4-chlorophenyl)-4-(1,3-diphenyl-4,5-dihydro-1H-
pyrazol-5-yl)-1H-pyrazole (E1). Light yellow solid
0.16 g,yield 40 %.APCI-MS (m/z,M++Na): 421.1. 1H
NMR(CDCl3) δ: 3.22(dd, 1H, J=16.8, 6.5Hz, pyrazoline-
H), 3.81(dd, 1H, J=16.8, 11.9Hz, pyrazoline-H), 5.36(dd,
1H, J=11.9, 6.6Hz, pyrazoline-H), 6.82–6.87(m, 1H, Ar-H),
7.16–7.23(m, 3H, Ar-H), 7.33–7.42(m, 5H, Ar-H), 7.43–
7.56(m, 3H, Ar-H), 7.70(s, 1H, Ar-H), 7.76–7.79(m, 3H,
Ar-H). IR(KBr, cm−1) ν: 3054(Ar-H), 2921(CH2),
1596(PyrazolineC=N), 1502, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 72.27; H, 4.80; N, 14.05. Found: C, 72.25; H, 4.86;
N, 1402.
1-(4-chlorophenyl)-4-(3-phenyl-1-p-tolyl-4,5-dihydro-1H-
pyrazol-5-yl)-1H-pyrazole (E2). Light yellow solid
0.14 g,yield 34 %.APCI-MS (m/z,M+): 413.2. 1H
NMR(CDCl3) δ: 2.26(s, 3H, CH3), 3.20(dd, 1H, J=16.7,
7.0Hz, pyrazoline-H), 3.79(dd, 1H, J=16.7, 11.9Hz,
pyrazoline-H), 5.31(dd, 1H, J=11.9, 7.0Hz, pyrazoline-H),
7.02–7.09(m, 3H, Ar-H), 7.28–7.38(m, 3H, Ar-H), 7.39–
7.47(m, 2H, Ar-H), 7.50–7.60(m, 3H, Ar-H), 7.69(s, 1H,
Ar-H), 7.72–7.76(m, 3H, Ar-H). IR(KBr, cm−1) ν: 3066(Ar-
H), 2929(CH2), 1613(PyrazolineC=N), 1500, 1477(C=C),
1243(C-N). Anal. Calc.: C, 72.72; H, 5.13; N, 13.57. Found:
C, 72.70; H, 5.16; N, 13.52.
4-(1-(3,4-dimethylphenyl)-3-phenyl-4,5-dihydro-1H-
pyrazol-5-yl)-1-(4-fluorophenyl)-1H-pyrazole (D3). Yellow
1
solid 0.14 g,yield 34 %.APCI-MS (m/z, M+):411.4. H
NMR(CDCl3) δ: 2.17(s, 3H, CH3), 2.22(s, 3H, CH3),
3.19(dd, 1H, J=16.7, 6.9Hz, pyrazoline-H), 3.79(dd, 1H, J=
16.7, 11.9Hz, pyrazoline-H), 5.31(dd, 1H, J=11.9, 6.9Hz,
pyrazoline-H), 6.81–6.84(m, 1H, Ar-H), 7.07–7.11(m, 2H,
Ar-H), 7.31–7.45(m, 4H, Ar-H), 7.52–7.57(m, 3H, Ar-H),
7.69(s, 1H, Ar-H), 7.73–7.75(m, 3H, Ar-H). IR(KBr, cm−1)
ν: 3028(Ar-H), 2920(CH2), 1611(PyrazolineC=N), 1514,
1477(C=C), 1243(C-N). Anal. Calc.: C, 76.08; H, 5.65; N,
13.65. Found: C, 76.06; H, 5.61; N, 13.61.
1-(4-chlorophenyl)-4-(1-(3,4-dimethylphenyl)-3-phenyl-
4,5-dihydro-1H-pyrazol-5-yl)-1H-pyrazole (E3). Yellow solid
0.15 g,yield 35 %.APCI-MS (m/z,M+): 427.2. 1H
NMR(CDCl3) δ: 2.17(s, 3H, CH3), 2.23(s, 3H, CH3),
3.19(dd, 1H, J=16.7, 6.9Hz, pyrazoline-H), 3.78(dd, 1H, J=
16.7, 11.8Hz, pyrazoline-H), 5.30(dd, 1H, J=11.8, 6.8Hz,
pyrazoline-H), 6.82(dd, 1H, J =8.1, 2.4Hz, Ar-H), 6.93–
7.03(m, 1H, Ar-H), 7.08(d, 1H, J=2.3Hz, Ar-H), 7.31–
7.36(m, 2H, Ar-H), 7.37–7.45(m, 3H, Ar-H), 7.52–7.56(m,
1-(4-fluorophenyl)-4-(1-(4-fluorophenyl)-3-phenyl-4,5-
dihydro-1H-pyrazol-5-yl)-1H-pyrazole (D4). Light yellow
1
solid 0.19 g,yield 48 %.APCI-MS (m/z, M+): 401.2. H
NMR(CDCl3) δ: 3.22(dd, 1H, J=16.8, 7.1Hz, pyrazoline-

J Fluoresc
2H, Ar-H), 7.70(s, 1H, Ar-H), 7.73–7.76(m, 3H, Ar-H).
I R ( K B r, c m − 1 ) ν : 3 0 6 5 ( A r - H ) , 2 9 1 9 ( C H 2 ) ,
1613(PyrazolineC=N), 1502, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 73.14; H, 5.43; N, 13.12. Found: C, 73.15; H, 5.46;
N, 13.10.
1-(4-chlorophenyl)-4-(1-(4-fluorophenyl)-3-phenyl-4,5-
dihydro-1H-pyrazol-5-yl)-1H-pyrazole (E4).Light yellow sol-
id 0.15 g,yield 35 %.APCI-MS (m/z,M+): 417.4. 1H
NMR(CDCl3) δ: 3.22(dd, 1H, J=16.7, 7.2Hz, pyrazoline-
H), 3.81(dd, 1H, J=16.7, 11.8Hz, pyrazoline-H), 5.28(dd,
1H, J=11.7, 7.2Hz, pyrazoline-H), 6.94(dd, 1H, J=11.9,
5.7Hz, Ar-H), 7.08–7.18(m, 2H, Ar-H), 7.33–7.47(m, 5H,
Ar-H), 7.50–7.60(m, 3H, Ar-H), 7.69(s, 1H, Ar-H), 7.72–
7.80(m, 3H, Ar-H). IR(KBr, cm−1) ν: 3054(Ar-H),
2924(CH2), 1600(PyrazolineC=N), 1509, 1477(C=C),
1243(C-N). Anal. Calc.: C, 69.15; H, 4.35; N, 13.44. Found:
C, 69.11; H, 4.38; N, 13.42.
1477(C=C), 1243(C-N). Anal. Calc.: C, 65.02; H, 4.32; N,
12.64. Found: C, 65.05; H, 4.36; N, 12.62.
1-(4-bromophenyl)-4-(3-phenyl-1-p-tolyl-4,5-dihydro-1H-
pyrazol-5-yl)-1H-pyrazole (F2). Light yellow solid
0.16 g,yield 35 %.APCI-MS (m/z,M+): 458.4. 1H
NMR(CDCl3) δ: 2.25(s, 3H, CH3), 3.20(dd, 1H, J=16.8,
7.0Hz, pyrazoline-H), 3.79(dd, 1H, J=16.7, 11.8Hz,
pyrazoline-H), 5.31(dd, 1H, J=11.8, 7.0Hz, pyrazoline-H),
7.02–7.08(m, 3H, Ar-H), 7.32–7.41(m, 3H, Ar-H), 7.47–
7.53(m, 5H, Ar-H), 7.70(s, 1H, Ar-H), 7.72–7.76(m, 3H,
Ar-H). IR(KBr, cm−1) ν: 3025(Ar-H), 2920(CH2),
1614(PyrazolineC=N), 1513, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 65.65; H, 4.63; N, 12.25. Found: C, 65.62; H, 4.66;
N, 12.22.
1-(4-bromophenyl)-4-(1-(3,4-dimethylphenyl)-3-phenyl-
4,5-dihydro-1H-pyrazol-5-yl)-1H-pyrazole (F3).Light yellow
1
solid 0.18 g,yield 38 %.APCI-MS (m/z, M+): 472.1. H
4-(1-(4-bromophenyl)-3-phenyl-4,5-dihydro-1H-pyrazol-
5-yl)-1-(4-chlorophenyl)-1H-pyrazole (E5). Light yellow sol-
NMR(CDCl3) δ: 2.16(s, 3H, CH3), 2.22(s, 3H, CH3),
3.19(dd, 1H, J=16.7, 6.9Hz, pyrazoline-H), 3.78(dd, 1H,
J=16.7, 11.9Hz, pyrazoline-H), 5.30(dd, 1H, J=11.9,
6.9Hz, pyrazoline-H), 6.80–6.84(m, 1H, Ar-H), 6.97(d,
1H, J=8.2Hz, Ar-H), 7.07(d, 1H, J=2.1Hz, Ar-H),
7.31–7.38(m, 2H, Ar-H), 7.40–7.43(m, 2H, Ar-H), 7.49–
7.51(m, 3H, Ar-H), 7.70(s, 1H, Ar-H), 7.73–7.76(m, 3H, Ar-
H). IR(KBr, cm−1) ν: 3025(Ar-H), 2921(CH2),
1614(PyrazolineC=N), 1497, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 66.25; H, 4.92; N, 11.89. Found: C, 66.27; H, 4.90;
N, 11.84.
1
id 0.19 g,yield 40 %.APCI-MS (m/z,M++Na): 500.8. H
NMR(CDCl3) δ: 3.23(dd, 1H, J=16.8, 6.3Hz, pyrazoline-
H), 3.82(dd, 1H, J=16.8, 11.8Hz, pyrazoline-H), 5.33(dd,
1H, J=11.9, 6.2Hz, pyrazoline-H), 7.01–7.05(m, 2H, Ar-H),
7.28–7.32(m, 2H, Ar-H), 7.34–7.47(m, 5H, Ar-H), 7.49–
7.56(m, 2H, Ar-H), 7.67(s, 1H, Ar-H), 7.72–7.76(m, 3H,
Ar-H). IR(KBr, cm−1) ν: 3059(Ar-H), 2929(CH2),
1591(PyrazolineC=N), 1500, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 60.33; H, 3.80; N, 11.73. Found: C, 60.35; H, 3.76;
N, 11.72.
1-(4-bromophenyl)-4-(1,3-diphenyl-4,5-dihydro-1H-
pyrazol-5-yl)-1H-pyrazole (F1). Light yellowsolid 0.16 g,yield
36 %.APCI-MS (m/z,M+): 444.6. 1H NMR(CDCl3) δ:
3.22(dd, 1H, J=16.8, 6.5Hz, pyrazoline-H), 3.81(dd, 1H, J=
16.8, 11.9Hz, pyrazoline-H), 5.35(dd, 1H, J=11.9, 6.5Hz,
pyrazoline-H), 6.82–6.85(m, 1H, Ar-H), 7.16–7.23(m, 3H,
Ar-H), 7.33–7.36(m, 3H, Ar-H), 7.39–7.62(m, 5H, Ar-H),
7.70(s, 1H, Ar-H), 7.69–7.77(m, 3H, Ar-H). IR(KBr, cm−1)
ν: 3052(Ar-H), 2920(CH2), 1595(PyrazolineC=N), 1498,
1-(4-bromophenyl)-4-(1-(4-fluorophenyl)-3-phenyl-4,5-
dihydro-1H-pyrazol-5-yl)-1H-pyrazole (F4).Light yellow sol-
1
id 0.12 g,yield 26 %.APCI-MS (m/z,M++K): ,500.8. H
NMR(CDCl3) δ: 3.22(dd, 1H, J=16.8, 7.1Hz, pyrazoline-
H), 3.81(dd, 1H, J=16.7, 11.8Hz, pyrazoline-H), 5.28(dd,
1H, J=11.7, 7.1Hz, pyrazoline-H), 6.93(t, 2H, J=8.8Hz, Ar-
H), 7.08–7.12(m, 2H, Ar-H), 7.35–7.44(m, 3H, Ar-H), 7.48–
7.54(m, 4H, Ar-H), 7.69(s, 1H, Ar-H), 7.72–7.76(m, 3H,
Ar-H). IR(KBr, cm−1) ν: 3031(Ar-H), 2920(CH2),
1618(PyrazolineC=N), 1502,1477(C=C), 1243(C-N).
R2
Fig. 1 The synthesis routes of
4-(1- aryl −3-phenyl-4, 5-
dihydro- 1H-pyrazol-5-yl)-1-
O
N
N
aryl-1H-pyrazole
NHNH2HCl
EtOH
+
N
N
N
N
HCl
R1
R1
R2
R1=H;R2=H(A1);4-CH3(A2);3,4-di-CH3(A3);4-F(A4);4-Br(A5)
R1=4-CH3;R2=H(B1);4-CH3(B2);3,4-di-CH3(B3);4-F(B4);4-Br(B5)
R1=3,4-di-CH3;R2=H(C1);4-CH3(C2);3,4-di-CH3(C3);4-F(C4);4-Br(C5)
R1=4-F;R2=H(D1);4-CH3(D2);3,4-di-CH3(D3);4-F(D4);4-Br(D5)
R1=4-Cl;R2=H(E1);4-CH3(E2);3,4-di-CH3(E3);4-F(E4);4-Br(E5)
R1=4-Br;R2=H(F1);4-CH3(F2);3,4-di-CH3(F3);4-F(F4);4-Br(F5)

J Fluoresc
Anal. Calc.: C, 62.48; H, 3.93; N, 12.14. Found: C,
62.47; H, 3.95; N, 12.11.
J=11.8, 6.2Hz, pyrazoline-H), 7.03(d, 2H, J=8.8Hz, Ar-H),
7.32(t, 2H, J=9.1Hz, Ar-H), 7.35–7.43(m, 3H, Ar-H), 7.47–
7.53(m, 4H, Ar-H), 7.67(s, 1H, Ar-H), 7.72–7.76(m, 3H, Ar-
H). IR(KBr, cm−1) ν: 3053(Ar-H), 2923(CH2),
1601(PyrazolineC=N), 1490, 1477(C=C), 1243(C-N). Anal.
Calc.: C, 55.20; H, 3.47; N, 10.73. Found: C, 55.17; H, 3.46;
N, 10.72.
1-(4-bromophenyl)-4-(1-(4-bromophenyl)-3-phenyl-4,5-
dihydro-1H-pyrazol-5-yl)-1H-pyrazole (F5). Light yellow sol-
id 0.12 g,yield 23 %.APCI-MS (m/z,M+): 523.0. 1H
NMR(CDCl3) δ: 3.23(dd, 1H, J=16.8, 6.2Hz, pyrazoline-H),
3.82(dd, 1H, J=16.7, 11.8Hz, pyrazoline-H), 5.30(dd, 1H,
2.0
2.0
B1
A
1
A
2
A
3
B2
B3
1.5
1.0
.5
B4
B5
1.5
1.0
.5
A
4
5
A
0.0
250
0.0
250
300
350
400
450
300
350
400
450
Wavelength/(nm)
Wavelength/(nm)
2.0
1.5
1.0
.5
C
1
2
3
4
5
C
C
C
C
1.4
1.2
1.0
.8
D
D
D
D
D
1
2
3
4
5
.6
.4
.2
0.0
0.0
250
300
350
400
450
250
300
350
400
450
Wavelength/(nm)
Wavelength/(nm)
2.5
2.0
1.5
1.0
.5
2.0
1.5
1.0
.5
F
1
F
2
F
3
F
4
E1
E2
E3
E4
E5
F
5
0.0
0.0
250
300
350
400
450
250
300
350
400
450
X Data
Wavelength/(nm)
Fig. 2 The UV–vis spectra of target compounds

J Fluoresc
Results and Discussion
or propionic acid was used as solvent, and the results were
improved when ethanol was used as solvent and diluted HCl
(0.8 mol·L−1) was used as catalyst. Maybe the lower boiling
point of ethanol and stronger acidity of HCl compared with
acetic acid were advantageous for this reaction. On the one
hand, we found that the proper ratio to chalcone was 1.2:1 for
phenylhydrazine and 1:1 for substituted phenylhydrazine hy-
drochloride in this reaction respectively. That is to say, the
appropriate excessive of phenylhydrazine is advantageous to
the reaction, but for substituted phenylhydrazine hydrochlo-
ride this is not necessary.
Synthesis
The synthetic route of 4-(1-aryl-3-phenyl-4, 5-dihydro-1H-
pyrazol-5-yl)-1-aryl-1H-pyrazole is shown in Fig. 1.
Under normal circumstances, the pyrazoline derivatives are
synthesized in solvent of acetic acid or propionic acid for the
excellent solubility property and catalytic performance. But in
our research, we found that the yield of this reaction was low
and the purification of product was difficult when acetic acid
3000
3000
A
1
2500
B
1
B
2
B
3
A
2
A
3
2500
A
2000
1500
1000
500
0
4
5
B
4
A
2000
B
5
1500
1000
500
0
350
400
450
500
550
600
650
350
400
450
500
550
600
650
Wavelength/(nm)
Wavelength/(nm)
3500
3000
2500
2000
1500
1000
500
3500
C
C
C
C
C
1
2
3
4
5
D
D
D
D
D
1
2
3
4
5
3000
2500
2000
1500
1000
500
0
350
0
350
400
450
500
550
600
650
400
450
500
550
600
650
Wavelength/(nm)
Wavelength/(nm)
3000
2500
2000
1500
1000
500
3000
2500
2000
1500
1000
500
F1
F2
F3
F4
F5
E
E
E
E
E
1
2
3
4
5
0
350
0
350
400
450
500
550
600
650
400
450
500
Wavelength/(nm)
550
600
650
Wavelength/(nm)
Fig. 3 The fluorescence spectra of target compounds

J Fluoresc
The structure of synthetic compounds has been character-
ized by mass spectrometry(MS), nuclear magnetic resonance
(NMR), infrared spectra (IR) and elemental analysis. Because
of different chemical environment of the 4-H in pyrazoline
ring, 5-H is splitted into quartet instead of the usual triplet in
the range of 5.27 to 5.37.
as p-Br and p-F cause a slight blue-shift (0-5 nm) of the fluores-
cent spectra and an increase of the fluorescence intensity, while
electron donating substituent like p-CH3 and 3,4-di-CH3 can
cause 5-17 nm red-shift (5-11 nm for A series, 13-17 nm for B
series, 10-15 nm for C series, 11-15 nm for D series, 12-15 nm
for E series and 10-14 nm for F series ) of the fluorescent spectra
and reduce the fluorescence intensity. The substitution effects on
the fluorescence spectrum display some abnormal situation (for
example, the effect of heavy atoms has not arised when R1 or R2
is p-Br ) and the same results have obtained after the tests were
repeated. So,we suppose that the combined action of the
nonradiative attenuation, p–π conjugation effect and the solvent
effect leads to the results.
UV–vis Spectrum
The UV–vis spectra of the six series of target compounds
measured in DMF are shown in Fig. 2, and their maximum
absorption wavelengths data are listed in Table s1. Within the
exploited wavelength range of 200–800 nm, there are two
remarkable absorption peaks at about 260 and 360 nm
(Fig. 2), which are attributed to the n- π* and π−π* transi-
tions, respectively. In the meantime, substituent R1 and R2 of
the phenyl group has influence on the absorption wavelength
and absorbance. On the one hand, the introduction of
auxochrome group such as -F, −Cl, −Br to the phenyl group
leads to p–π conjugation formed by nonbonding electron with
π electron and shift of absorption peak towards longer wave-
length. On the other hand, the introduction of alkyl group to
the conjugated systems allows the electron of C-H bond of the
alkyl group to overlap with the π electron of the conjugated
system (the so-called hyperconjugation), also leading to shift
of the absorption peak towards longer wavelength.
Influence of Metal Ions on Spectral Properties of Compounds
A5
The influence of metal ions on the fluorescence spectrum of
compound A5 is shown in Fig. 4 and the spectrum data are
listed in Table s3. It can be seen that the addition of metal ions
has a weak impact on the maximum emission peak of com-
pound A5 (red-shift 1-3 nm). But the fluorescence intensity of
compound A5 reduced to different degree after the addition of
different metal ions. Especially, the fluorescence of compound
A5 is quenched over 2/3 when Co2+ is added. The experimen-
tal results imply that synthetic products maybe have the func-
tion of selective recognition to Co2+.
Fluorescence Spectrum
Conclusion
The fluorescence spectra of the target compounds are shown in
Fig. 3, and their maximum emission wavelengths data are listed
in Table s2. The target compounds show the maximum emission
peak at 445-467 nm (Table s2). The experimental results show
that R2 has major impact on the fluorescence spectra of the target
compounds while this influence caused by R1 is negligible.
Compared with R2 is H, electron withdrawing substituents such
Six series of pyrazoline derivatives containing pyrazole group
were synthesized and characterized by means of 1H NMR, FT-
IR, MS and elemental analysis, and their UV–vis absorption
behavior and fluorescent properties were also measured.
Moreover, the influence of metal ions on spectral properties
of synthetic products was examined with compound A5 as an
example. The experimental results show that synthetic prod-
ucts have the function of selective recognition to Co2+.
3000
A5
Cu2+
Zn2+
Mn2+
Co2+
Cd2+
Fe3+
Mg2+
Ca2+
Na+
2500
2000
1500
1000
500
References
Pb2+
Sn2+
In3+
1. Babu VH, Sridevi C, Joseph A, Srinivasan KK (2008) Synthesis and
biological evaluation of some novel pyrazolines. Ind J Pharm Sci 69:
470–473
2. Chimenti F, Bizzarri B, Manna F, Bolasco A, Secci D, Chimenti P,
Granese A, Rivanera D, Lilli D, Scaltrito MM, Brenciaglia MI (2005)
Synthesis and in vitro selective anti-helicobacter pylori activity of
pyrazoline derivatives. Bioorg Med Chem Lett 15:603–607
3. Chimenti F, Fioravanti R, Bolasco A, Manna F, Chimenti P, Secci D,
Rossi F, Turini P, Ortuso F, Alcaro S, Cardia MC (2008) Synthesis,
molecular modeling studies and selective inhibitory activity against
0
350
400
450
500
550
600
650
Wavelength/(nm)
Fig. 4 Influence of metal ions on spectral properties of compounds A5

J Fluoresc
MAO of N1-propanoyl-3,5-diphenyl-4,5-dihydro-(1H)-pyrazole de-
11. Ren TG, Cheng HB, Zhang JL et al (2012) Synthesis of benzimid-
azoles containing pyrazole group and quantum chemistry calculation
of their spectroscopic properties and electronic structure. J Fluoresc
22:201–212
12. Ren TG, Liu SY, Li GH et al (2012) Synthesis, spectroscopic
properties and theoretical studies of bis-Schiff bases derived
from polyamine and pyrazolones. Spectrochim Acta Part A
97:167–175
rivatives. Eur J Med Chem 43:2262–2267
4. Kumar S, Bawa S, Drabu S, Kumar R, Gupta H (2009) Biological
activities of pyrazoline derivatives-a recent development. Recent Pat
Antiinfect Drug Discov 4:154–163
5. McCann SF, Annis GD, Shapiro R et al (2001) The discovery of
indoxacarb: oxadiazines as a new class of pyrazoline-type insecti-
cides. Pest Manage Sci 57:153–164
6. Takeshi S, Takanori F, Yoshitaka N et al (1995) Pyrazoline dimers for
hole transport materials in organic electroluminescent devices. Jpn J
Appl Phys 34:3124–3127
13. Banerjee P, Pramanik S, Sarkar A, Bhattacharya SC (2008)
Modulated photophysics of 3-pyrazolyl-2- pyrazoline deriva-
tive entrapped in micellar assembly. J Phys Chem B112:7211–
7219
14. Shi HB, Ji SJ, Bian B (2007) Studies on transition metal ions
recognition properties of 1-(2-benzothiazole)-3-(2-thiophene)-2-
pyrazoline derivatives. Dyes Pigments 73:394–396
7. Mnna F, Chimenti F, Bolasco A et al (2002) Inhibition of amine
oxidases activity by 1-acetyl-3,5-diphenyl-4,5-dihydro-(1H)-
pyrazole derivatives. Bioorg Med Chem Lett 12:3629–3633
8. Ozdemir A, Turan-Zitouni G, Kaplancikli ZA et al (2007) Synthesis
and antimicrobial activity of 1-(4-aryl-2-thiazolyl)-3-(2-thienyl)-5-
aryl-2-pyrazoline derivatives. Eur J Med Chem 42:403–409
9. Wagner A, Schellhammer CW, Petersen S (1966) Aryl-Δ2-
pyrazolines as optical brighteners. Angew Chem Int Ed 5:699–704
10. Wang PF, Onozawa-Komutsuzaki N, Himeda Y et al (2001) 3-(2-
Pyridyl)-2-pyrazoline derivatives: novel fluorescent probes for Zn2+
ion. Tetrahedron Lett 42:9199–9201
15. Xu ZX, Wu J, Shen J (2010) Synthesis of 1,5-diaryl-3-(2-hydroxyl-4,
6-dimethoxylphenyl)-2-pyrazolines as fluorescent Sensors for Cu2+
.
Chem J Chin Univ (in Chinese) 31:1570–1573
16. Rossella F, Nicoletta D, Mariangela B, Luca Proietti M, Laura G,
Matilde Y (2013) Design, synthesis, and in vitro hMAO-B inhibitory
evaluation of some 1-methyl-3,5-diphenyl-4,5-dihydro-1H-
pyrazoles. Bioorg Med Chem Lett 23:5128–5130