Selective fluorescence sensing of ferric ion with novel triazolethione Schiff bases probes

Article abstract of DOI:10.1515/hc-2013-0021

New triazolethione Schiff base derivatives 3a-f were synthesized. The structures of the products were characterized by elemental analysis, ¹H NMR, ¹³C NMR, IR and MS. Their complexation properties to different heavy and transition me

Full text of DOI:10.1515/hc-2013-0021

ꢁꢁꢁꢂ
ꢀHeterocycl. Commun. 2013; 19(4): 249–252
DOI 10.1515/hc-2013-0021ꢀ
Wei Wang, Junwu Wang, Xiaoyu Jiang, Kui Yang, Qiang Zhang and Yan Gao*
Selective fluorescence sensing of ferric ion with
novel triazolethione Schiff bases probes
Abstract: New triazolethione Schiff base derivatives 3a–f pollutants that are nonbiodegradable and have environ-
were synthesized. The structures of the products were mental, public health and economic impacts [1]. In this
characterized by elemental analysis, 1H NMR, 13C NMR, IR regard, metal-selective fluorescent probes have been
and MS. Their complexation properties to different heavy widely exploited to detect biologically or environmentally
and transition metal ions were studied by UV-Vis and relevant metal ions [2–6]. However, very few fluorescent
fluorescence spectroscopy. Compound 3a shows selec- sensors for Fe3+ have been reported.
tive recognition of Fe3+ with a 1:1 stoichiometric complex
formation.
Schiff base derivatives are frequently utilized as
sensors for anions and alkaline earth cations [7–10].
Recently, some Schiff base-based fluorescent probes have
Keywords: ferric ion; fluorescence; recognition; Schiff also been utilized to detect heavy and transition metal
bases; triazolethione.
ions [11–13]. There are few reports about the triazole Schiff
base derivatives for recognition of Fe3+ [14, 15]. In this
work, six new triazolethione Schiff base derivatives were
synthesized and preliminary complexation to heavy and
transition metal ions were studied. The results show that
compound 3a displays a highly selective and sensitive
response towards Fe3+ in CH2Cl2/DMF media.
*Corresponding author: Yan Gao, School of Chemical Engineering,
University of Science and Technology Liaoning, Anshan 114051, P.R.
China, e-mail: gys20080901@yahoo.com.cn
Wei Wang, Junwu Wang, Xiaoyu Jiang, Kui Yang and Qiang Zhang:
School of Perfume and Aroma Technology, Shanghai Institute of
Technology, Shanghai 200235, P.R. China
Results and discussion
The synthetic route to triazolethione Schiff bases deriva-
Introduction
Contamination of water by heavy metal ions is a serious tives 3a–f is shown in Scheme 1. The final compounds
environmental problem. Heavy metals can be toxic were characterized by elemental analysis, 1H NMR,
O
S
O
CS2, KOH
EtOH
NH2NH2 H2O
Me
SK
Me
Me
HN NH
HN NH2
O
O
Ph
N
N
Ph
N
N
N
N
N
NH
Me
Me
AcOK
S
N
H2N
S
SH
H2N
H2N
1
2
OH
3a: Ar =
O
Ph
3b: Ar = Ph
N
N
Ph
ArCHO
AcOH
N
3c
: Ar = 4-Cl-C6H4
Me
S
3d: Ar = 2-Cl-C6H4
N
3e
: Ar = 4-OMe-C6H4
3a-f
Ar
3f: Ar = 4-OMe-3-OH-C6H3
Scheme 1ꢀ
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ꢀW. Wang et al.: Selective fluorescence sensing of ferric ion
1.6
1.4
Fe3+/10-5
5.0
M
800
700
600
500
400
300
200
100
0
3.0
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.4
0.2
0.0
1.2
1.0
Fe3+
0.8
0.6
0.4
0.2
0.0
3a, Ca2+, Cd2+, Cu2+, Mn2+
Hg2+, Ni2+, Pb2+, Zn2+
Mg2+, Na+, Al3+, Ag+
Cr3+
300
400
500
600
700
300
350
400
450
500
Wavelength (nm)
Wavelength (nm)
Figure 3ꢀFluorescene emission spectra of 3a (10 μm) for Fe3+ ion
titration in CH2Cl2 and DMF (v/v = 9:1) (λex = 386 nm).
Figure 1ꢀUV-Vis spectra of compound 3a (10 μm) upon addition of
various metal ions (20 μm) in CH2Cl2 and DMF (v/v = 9:1).
13C NMR, IR and MS. All analytical data were in agreement Figure 2. Metal-free compound 3a exhibits weak fluores-
with the desired structures.
cence emission at 445 nm. Upon the addition of 2 equiv. of
Complexation properties of compounds 3a–f towards Fe3+, the fluorescence intensity is significantly enhanced
various heavy and transition metal cations including Ca2+, and the wavelength is red-shifted by 18 nm. Because addi-
Cd2+, Cu2+, Hg2+, Mn2+, Ni2+, Pb2+, Zn2+, Mg2+, Na+, Al3+, Fe3+, tion of Cr3+ does not cause remarkable response, it may
Ag+ and Cr3+ were investigated by using UV-Vis and fluo- be concluded that 3a is a selective and sensitive agent for
rescence spectroscopy. It was found that compound 3a is complexation of Fe3+.
the most selective agent for recognition of Fe3+. As shown
The titration of probe 3a by Fe3+ using excitation at
in Figure 1, the absorption maximum band of metal-free λex = 386 nm is given in Figure 3. With an increase in
compound 3a is observed at 367 nm. When Fe3+ is added, concentration of Fe3+, the fluorescence spectra exhibit
the absorption band is increased in intensity and blue- an increase in emission intensity at 463 nm. Because a
shifted to approximately 358 nm. The addition of Cr3+ single isosbestic point is observed, a single equilibrium
causes a small change in the spectrum, and even smaller is reached during complexation. The binding constant
changes are observed after addition of other metal ions.
determined from the titrations of 3a with Fe3+ is 3.21 × 106.
For the complexation ratio between compound 3a
The fluorescence spectra of compound 3a in the pres-
ence of Fe3+ and Cr3+ in CH2Cl2/DMF solution are shown in and Fe3+ ion, the Job’s plot experiment by varying the
700
Fe3+
450
600
400
500
350
Cr3+
400
300
200
300
250
200
150
100
50
3a
100
0
300
400
500
Wavelength (nm)
600
700
0.0
0.2
0.4
0.6
0.8
1.0
Mole fraction of Fe3+
Figure 2ꢀFluorescence emission spectra of compound 3a upon
addition of Fe3+ and Cr3+ (20 μm) in CH2Cl2 and DMF (v/v = 9:1).
Figure 4ꢀJob’s plot for compound 3a and Fe3+ (λex = 386 nm).
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concentrations of both compound 3a and Fe3+ ion was con-
ducted. As shown in Figure 4, the maximum point at the
molar fraction of 0.5 indicates the complexation ratio of 1:1.
3-[3-(p-Methylphenyl)-4-benzylideneamino-5-thioxo-4,5-dihy-
dro-1H-1,2,4-triazol-1-yl]-1,3-diphenylpropan-1-one (3b)ꢀYield
74%; mp 179–181°C (dec); IR: 3263, 3056, 2958, 2893, 1675, 1606, 1464,
1426, 1352, 1264, 1151, 823, 751, 690 cm-1; 1H NMR: δ 10.22 (s, 1H, CH =
N), 8.04 (d, 2H, J = 7.5 Hz, Ar-H), 7.86 (d, 2H, J = 7.0 Hz, Ar-H), 7.77 (d,
2H, J = 8.0 Hz, Ar-H), 7.65 (d, 2H, J = 7.0 Hz, Ar-H), 7.60 (t, 1H, J = 7.0
Hz, Ar-H), 7.53 (d, 1H, J = 7.0 Hz, Ar-H), 7.49 (m, 4H, Ar-H), 7.40 (t, 2H,
J = 7.0 Hz, Ar-H), 7.34 (t, 1H, J = 7.0 Hz, Ar-H), 7.25 (d, 2H, J = 8.0 Hz,
Ar-H), 6.88 (dd, 1H, J1 = 9.0 Hz, J2 = 5.0 Hz, CH), 4.47 (dd, 1H, J1 = 18.0
Hz, J2 = 9.0 Hz, CH2), 3.78 (dd, 1H, J1 = 18.0 Hz, J2 = 5.0 Hz, CH2), 2.41
(s, 3H, CH3); 13C NMR: δ 195.8, 163.3, 162.2, 148.4, 140.9, 138.5, 136.6,
133.3, 132.7, 132.3, 129.1, 128.9, 128.8, 128.7, 128.7, 128.6, 128.22, 128.2,
127.7, 122.8, 57.1, 42.9, 21.5; MS: m/z 503.6 (M+H+). Anal. Calcd for
C31H26N4OS: C, 74.14; H, 5.18; N, 11.19. Found: C, 74.08; H, 5.21; N, 11.15.
Conclusion
Of the six new triazolethione Schiff bases, compound 3a
displays selective fluorescence change upon the addition
of Fe3+ in the presence of other metal ions. This system
provides potential fluorescent probe for Fe3+.
3-[3-(p-Methylphenyl)-4-(4-chlorobenzylideneamino)-5-thi-
oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]-1,3-diphenylpropan-1-one
(3c)ꢀYield 75%; mp 164–166°C (dec); IR: 3008, 2945, 2873, 1687, 1670,
1603, 1507, 1454, 1376, 1344, 817, 747, 697 cm-1; 1H NMR: δ 10.298 (s, 1H,
CH = N), 8.03 (d, 2H, J = 8.0 Hz, Ar-H), 7.77 (d, 2H, J = 8.5 Hz, Ar-H),
7.73 (d, 2H, J = 8.5 Hz, Ar-H), 7.64 (d, 2H, J = 7.5 Hz, Ar-H), 7.59 (t, 1H,
J = 7.5 Hz, Ar-H), 7.48 (m, 4H, Ar-H), 7.39 (t, 2H, J = 7.0 Hz, Ar-H), 7.33
(t, 1H, J = 7.5 Hz, Ar-H), 7.26 (t, 2H, J = 9.5 Hz, Ar-H), 6.86 (dd, 1H,
J1 = 9.5 Hz, J2 = 5.0 Hz, CH), 4.47 (dd, 1H, J1 = 18.0 Hz, J2 = 9.5 Hz, CH2),
3.75 (dd, 1H, J1 = 18.0 Hz, J2 = 5.0 Hz, CH2), 2.40 (s, 3H, CH3); 13C NMR:
δ 195.8, 162.1, 161.3, 148.5, 141.0, 138.4, 136.6, 133.4, 131.3, 129.9, 129.3,
129.2, 128.8, 128.7, 128.2, 128.21, 127.7, 122.7, 57.1, 42.8, 21.5; MS: m/z
538.1 (M+H+). Anal. Calcd for C31H25N4OSCl: C, 69.40; H, 4.66; N, 10.38.
Found: C, 69.33; H, 4.69; N, 10.43.
Experimental
3-(p-Methylphenyl)-4-amino-5-mercapto-1,2,4-triazol 1 [16] and chal-
cone [17] were prepared as previously described. Other reagents were
obtained from commercial sources and used without further purifica-
tion. Melting points were measured on a Yanagimoto MP-500 appa-
ratus and are uncorrected. IR spectra were obtained in KBr pellets on
a Perkin Elmer spectrophotometer. Mass spectral data were obtained
on an Agilent 1100 LC/MS instrument. H NMR (500 MHz) and 13C
1
NMR (125 MHz) spectra were recorded in CDCl3 at room temperature
on a Bruker Avance-500 spectrometer.
General procedure for synthesis of
compounds 3a–f
3-[3-(p-Methylphenyl)-4-(2-chlorobenzylideneamino)-5-thi-
oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]-1,3-diphenylpropan-1-one
(3d)ꢀYield 79%; mp 160–162°C (dec); IR: 3015, 2960, 2871, 1685, 1669,
1593, 1499, 1467, 1378, 1348, 811, 738, 699 cm-1; 1H NMR: δH (ppm) 10.84
(s, 1H, CH = N), 8.08 (q, 3H, J = 7.5 Hz, Ar-H), 7.75 (d, 2H, J = 8.0 Hz,
Ar-H), 7.67 (d, 2H, J = 7.5 Hz, Ar-H), 7.61 (t, 1H, J = 7.5 Hz, Ar-H), 7.500
(m, 4H, Ar-H), 7.41 (t, 2H, J = 7.5 Hz, Ar-H), 7.34 (t, 2H, J = 7.0 Hz, Ar-H),
7.26 (d, 2H, J = 8.0 Hz, Ar-H), 6.89 (dd, 1H, J1 = 9.0 Hz, J2 = 5.0 Hz, CH),
4.47 (dd, 1H, J1 = 18.0 Hz, J2 = 9.0 Hz, CH2), 3.79 (dd, 1H, J1 = 18.0 Hz,
J2 = 5.0 Hz, CH2), 2.41 (s, 3H, CH3); 13C NMR: δ 195.8, 162.2, 159.1, 148.6,
140.9, 138.4, 136.6, 136.6, 133.3, 132.9, 130.8, 130.2, 129.2, 128.8, 128.7,
128.7, 128.6, 128.2, 128.2, 127.9, 127.8, 127.1, 122.8, 57.1, 42.8, 21.50; MS:
m/z 538.1 (M+H+). Anal. Calcd for C31H25N4OSCl: C, 69.38; H, 4.67; N,
10.48. Found: C, 69.33; H, 4.69; N, 10.43.
A magnetically stirred mixture of chalcone (0.05 mol) and K2CO3
(0.05 mol) in methanol (30 mL) was treated with 3-(p-methylphenyl)-
4-amino-5-mercapto-1,2,4-triazol 1 (0.04 mol). The mixture was heat-
ed under reflux for 8 h, and then cooled. The resulting solid of 2 was
filtered and crystallized from ethanol. A solution of 2 (0.02 mol) and
aromatic aldehyde (0.02 mol) in glacial acetic acid (25 mL) was stirred
and heated under reflux for 12 h. The insoluble impurities were then
filtered out from the hot solution and the solution was concentrated
under reduced pressure. The residue was crystallized from ethanol to
give analytically pure product 3a–f.
3-[3-(p-Methylphenyl)-4-(2-hydroxynaphthylmethyleneamino)-
5-thioxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]-1,3-diphenylpropan-
3-[3-(p-Methylphenyl)-4-(4-methoxybenzylideneamino)-5-thi-
1-one (3a)ꢀYield 69%; mp 164–166°C (dec); IR: 3252, 3024, 2979, oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]-1,3-diphenylpropan-1-one
1
2861, 1677, 1601, 1468, 1458, 1350, 1257, 1151, 747, 696 cm-1; H NMR: δ (3e)ꢀYield 77%; mp 146–148°C (dec); IR: 3005, 2959, 2867, 1690, 1671,
11.44 (s, 1H, CH = N), 11.29 (s, 1H, OH), 8.15 (d, 1H, J = 8.5 Hz, Ar-H), 1607, 1493, 1464, 1380, 1345, 845, 741, 702 cm-1; 1H NMR: δH (ppm) 9.93
8.04 (d, 2H, J = 7.5 Hz, Ar-H), 8.01 (d, 1H, J = 7.5 Hz, Ar-H), 7.90 (t, 2H, (s, 1H, CH = N), 8.06 (d, 2H, J = 8.0 Hz, Ar-H), 7.79 (d, 2H, J = 8.0 Hz,
J=8.5Hz,Ar-H),7.79(d,1H,J=8.0Hz,Ar-H),7.68(d,2H,J=8.0Hz,Ar-H), Ar-H), 7.672 (d, 2H, J = 7.0 Hz, Ar-H), 7.62 (d, 2H, J = 7.5 Hz, Ar-H), 7.51
7.62 (m, 4H, Ar-H), 7.49 (m, 2H, Ar-H), 7.42 (d, 2H, J = 7.5 Hz, Ar-H), (m, 1H, Ar-H), 7.41 (m, 5H, Ar-H), 7.25 (t, 2H, J = 8.0 Hz, Ar-H), 7.03 (d,
7.39 (t, 2H, J = 7.0 Hz, Ar-H), 7.16 (d, 1H, J = 9.0 Hz, Ar-H), 6.89 (dd, 2H, J = 8.0 Hz, Ar-H), 6.914 (dd, 1H, J1 = 9.0 Hz, J2 = 5.0 Hz, CH), 4.4
1H, J1 = 9.0 Hz, J2 = 5.0 Hz, CH), 4.51 (dd, 1H, J1 = 18.0 Hz, J2 = 9.0 Hz, (dd, 1H, J1 = 18.0 Hz, J2 = 9.0 Hz, CH2), 3.90 (s, 3H, OCH3), 3.78 (dd, 1H,
CH2), 3.77 (dd, 1H, J1 = 18.0 Hz, J2 = 5.0 Hz, CH2), 2.41 (s, 3H, CH3); 13C J1 = 18.0 Hz, J2 = 5.0 Hz, CH2), 2.42 (s, 3H, CH3);13C NMR: δ 195.8, 164.0,
NMR: δ 195.8, 162.5, 160.9, 148.3, 138.4, 136.5, 135.8, 133.4, 133.4, 129.6, 162.2, 149.9, 148.1, 146.9, 140.9, 138.6, 136.6, 133.2, 129.1, 128.7, 128.7,
128.9, 128.8, 128.7, 128.7, 128.5, 128.4, 127.6, 124.2, 120.8, 119.0, 107.4, 128.6, 128.2, 128.1, 127.7, 125.1, 124.9, 122.9, 114.4, 57.2, 55.5, 42.9, 21.5;
58.1, 42.8, 21.0; MS: m/z 569.7 (M+H+). Anal. Calcd for C35H28N4O2S: C, MS: m/z 533.7 (M+H+). Anal. Calcd for C32H28N4O2S: C, 72.23; H, 5.27; N,
73.85; H, 4.93; N, 9.91. Found: C, 73.92; H, 4.96; N, 9.85.
10.57. Found: C, 72.16; H, 5.30; N, 10.52.
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252ꢀ
3-[3-(p-Methylphenyl)- 4-( 3-hydroxy- 4-methoxyben-
zylideneamino)-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]-1,3-
diphenylpropan-1-one (3f)ꢀYield 73%; mp 175–177°C (dec); IR:
146.9, 140.9, 138.5, 136.6, 133.3, 129.1, 128.7, 128.7, 128.6, 128.2, 128.2,
127.7, 125.1, 124.9, 122.9, 114.6, 109.2, 57.2, 56.1, 42.9, 21.5; MS: m/z 549.7
(M+H+). Anal. Calcd for C32H28N4O3S: C, 70.13; H, 5.11; N, 10.25. Found:
3286, 3019, 2951, 2881, 1693, 1672, 1594, 1497, 1452, 1379, 1342, 885, C, 70.05; H, 5.14; N, 10.21.
815, 734, 703 cm-1; 1H NMR: δ 9.851 (s, 1H, CH = N), 8.06 (d, 2H, J = 8.0
Hz, Ar-H), 7.79 (d, 2H, J = 8.0 Hz, Ar-H), 7.67 (d, 2H, J = 7.5 Hz, Ar-H),
Acknowledgments: We acknowledge the financial sup-
port of the Natural Science Foundation of Liaoning
Education Department (2008S127).
7.619 (t, 1H, J = 7.0 Hz, Ar-H), 7.51 (m, 3H, Ar-H), 7.41 (t, 2H, J = 7.0 Hz,
Ar-H), 7.36 (d, 2H, J = 7.0 Hz, Ar-H), 7.33 (t, 1H, J = 7.5 Hz, Ar-H), 7.25
(d, 1H, J = 8.0 Hz, Ar-H), 7.02 (d, 1H, J = 8.0 Hz, Ar-H), 6.89 (dd, 1H,
J1 = 9.0 Hz, J2 = 5.0 Hz, CH), 6.07 (s, 1H, OH), 4.48 (dd, 1H, J1 = 18.0 Hz,
J2 = 9.0 Hz, CH2), 3.94 (s, 3H, OCH3), 3.79 (dd, 1H, J1 = 18.0 Hz, J2 = 5.0
Hz, CH2), 2.41 (s, 3H, CH3); 13C NMR: δ 195.8, 164.4, 162.3, 149.9, 148.1,
Received January 31, 2013; accepted May 31, 2013
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