A 1,8-naphthyridine-based fluorescent chemodosimeter for the rapid detection of Zn2+ and Cu2+

Article abstract of DOI:10.1021/ol8018192

(Figure Presented) A novel fluorescent chemodosimeter based on 1,8-naphthyridine exhibits high selectivity to Zn²⁺ and Cu ²⁺. When 1-(7-acetamino-1,8-naphthyridyl)-2-(6-diacetaminopyridyl) ethene was mixed with CuCl₂, hydrolysis of the acetamino group catalyzed by Cu²⁺ complex was first observed. Resulting from coordination and hydrolysis catalyzed by the corresponding complex of Zn ²⁺ or Cu²⁺, the highly effective fluorescent detection of Zn²⁺ and Cu₂₊ is realized with Zn²⁺-selective dual-emission and Cu²⁺-selective ON-OFF behavior.

Full text of DOI:10.1021/ol8018192

Supporting Information (SI)
A 1,8-Naphthyridine-based Fluorescent chemodosimeter for the Rapid
Detection of Zn2+ and Cu2+
Ming-Ming Yu, Zhan-Xian Li, Liu-He Wei,* Dong-Hui Wei, Ming-
Sheng Tang*,
Department of Chemistry, Zhengzhou University, Zhengzhou 450001, China
weiliuhe@zzu.edu.cn
Table of contents
1. Experimental
2
2. Changes in Absorption and Emission Spectra of 1 upon Addition of Various Metal Ions
3. Radiative Decay Curves of 1 in Methanol befoure, after Addition of Zn2+ and Cu2+
4. X-ray Crystallography
11
16
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1. Experimental
General instruments
For chromatography, 160−200 mesh silica gel (Qingdao, China) was employed. 1H, 13C spectra were recorded on a
Varian Mercury Bruker 400 spectrometer. Chemical shifts are reported in ppm using tetramethylsilane (TMS) as the
internal standard. Mass spectra were obtained on a VG ZAB-HS mass spectrometer or a Finnigan LCQ mass
spectrometer. All spectral measurements were carried out at 20˚C. UV-Vis absorption spectra were measured on a
Hitachi UV-3100 spectrophotometer and fluorescence spectra were determined on a Hitachi F-4500 spectrophotometer.
The fluorescence lifetime was obtained from an Edinburgh LhifeSpecps fluorescence lifetime spectrometer.
Synthetic procedure and characterization data
Synthetic procedure of 1-(7-acetamino-1,8-naphthyridyl)-2-(6-diacetamino-pyridyl)-ethene (1):
A mixture of 2-amino-3-aldehyde-pyridine (0.795g, 5mmol), 2-Amino-7-methyl-1,8-naphthyridine (0.61 g, 5 mmol),
and acetic anhydride (20 mL) was stirred and refluxed at 140°C for 24h under N2. The mixture was subsequently
poured into ice water (100 mL) and stirred overnight. The obtained yellow solid was filtered off, washed thoroughly
with water, and dried to afford crude product. Pale yellow sample (1.5g) was obtained from column chromatography
over silica gel column using chloroform/ethanol (10:1) as eluent. Yield: 80%. The structure of compound 1 was
confirmed by m.p.,1H NMR, 13C NMR, FTIR, Elemental analysis, and X-ray crystal structure determination. Selected
1
data for 1: mp 180 – 181 °C. H NMR (CDCl3, 400 MHz): δ (ppm) 8.59 (m, 1H), 8.53 (d, 1H, J= 8.8 Hz), 8.18 (m,
3H), 7.67 (d, 1H, J= 16.2 Hz), 7.56 (d, 1H, J= 8.3 Hz), 7.48 (m, 1H), 7.37 (d, 1H, J= 16.2 Hz), 2.33 (s, 9 H). 13C NMR
(CDCl3, 100 MHz ): δ (ppm) 25.0, 26.7, 115.1, 120.0, 120.1, 124.9, 128.1, 131.2, 133.8, 136.1, 137.3, 139.4, 149.7,
150.8, 154.0, 157.9, 172.5. IR (KBr, cm-1): 3395, 1701, 1597, 1504, 1428, 1400, 1368, 1307, 1286, 1255, 1137, 1031,
850, 807. Elemental analysis calcd (%) for C21H19N5O3: C 64.77, H 4.92, N 17.98; found: C 64.35, H 5.22, N 17.61.
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1H NMR of 1-(7-acetamino-1,8-naphthyridyl)-2-(6-diacetamino-pyridyl)-ethene (1):
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13C NMR of 1-(7-acetamino-1,8-naphthyridyl)-2-(6-diacetamino-pyridyl)-ethene (1):
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Synthesis of 2-diacetamino-3-methyl-pyridine (4):
To the 2-amino-3-methyl-pyridine (2 g, 18.5 mmol) was added an excess of acetic anhydride, and the mixture was
refluxed for 4 h. After cooling, it was filtered and pale yellow sample was obtained from column chromatography over
silica gel column using dichloromethane as eluent. Yield: 70%. mp 67 – 68 °C. 1H NMR (CDCl3, 400 MHz): δ (ppm)
8.45 (m, 1H), 7.68 (m, 1H), 7.31 (m, 1H), 2.26 (s, 6H), 2.21 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ (ppm) 17.2, 26.4,
124.5, 131.9, 140.1, 147.6, 151.7, 172.2. IR (KBr, cm-1): 3232, 3014, 1668, 1530, 1450, 1296, 1120, 809. Elemental
analysis calcd (%) for C10H12N2O2: C 62.49, H 6.29, N 14.57; found: C 62.46, H 6.29, N 14.63.
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1H NMR of 2-diacetamino-3-methyl-pyridine (4)
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13C NMR of 2-diacetamino-3-methyl-pyridine (4)
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Synthesis of 7-acetamino-2-methyl-1,8-naphthyridine (5):
7-acetamino-2-methyl-1,8-naphthyridine was synthesized from 2,6-diaminopyridine according to reference method.1
Yield: 85%. mp 278 – 281 °C. 1H NMR (CDCl3): δ (ppm) 8.47 (d, 1H, J= 8.8 Hz), 8.14 (d, 1H, J= 2.4 Hz), 8.02 (d, 1H,
J= 7.6 Hz), 7.28 (d, 1H, J= 11.6 Hz), 2.77 (s, 3H), 2.29 (s, 3H). 13C NMR (CDCl3): δ (ppm) 25.6, 77.0, 114.2, 121.6,
136.4, 139.1, 153.4, 163.3, 169.5. IR (KBr, cm-1): 3174, 3008, 1701, 1609, 1501, 1436, 1395, 1377, 1281, 1242, 1137,
1009, 853, 792, 623. Elemental analysis calcd (%) for C11H12N3O: C 65.66, H 5.51, N 20.88; found: C 65.88, H 5.60,
N 20.79.
References
(1) (a) Kelly, T. R.; Zhao, C.; Bridger, G. J. J. Am. Chem. Soc. 1989, 111, 3744. (b) Kelly, T. R.; Bridger, G. J.;
Zhao, C. J. Am. Chem. Soc. 1990, 112, 8024.
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1H NMR of 7-acetamino-2-methyl-1,8-naphthyridine (5)
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13C NMR of 7-acetamino-2-methyl-1,8-naphthyridine (5)
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2. Changes in Absorption and Emission Spectra of 1 upon Addition of Various Metal Ions
A
B
Fig. S1 Absorption spectra change of 1 (5.0 × 10−5 M) in methanol upon addition of Zn2+ (A) and Cu2+ (B). The metal
ions is 2 equivalent to 1.
Fig. S2 Fluorescence emission spectra of 1 in ethanol upon addition of Zn2+ ion (λex = 362 nm).
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Fig. S3 Fluorescence emission spectra of 1 in ethanol upon addition of Cu2+ ion (λex = 362 nm).
Fig. S4 Fluorescence emission spectra of 1 in ethanol upon addition of Zn(NO3)2 (λex = 362 nm).
Fig. S5 Fluorescence emission spectra of 1 in ethanol upon addition of Cu(NO3)2 (λex = 362 nm).
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Fig. S6 Fluorescence emission spectra of 1 in ethanol upon addition of CuSO4 (λex = 362 nm).
Fig. S7 Fluorescence emission spectra of 1 in methanol upon addition of Ca2+ ion (λex = 362 nm).
Fig. S8 Fluorescence emission spectra of 1 in methanol upon addition of Cr3+ ion (λex = 362 nm).
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Fig. S9 Fluorescence emission spectra of 1 in methanol upon addition of Hg 2+ ion (λex = 362 nm).
Fig. S10 Fluorescence emission spectra of 1 in methanol upon addition of K+ ion (λex = 362 nm).
Fig. S11 Fluorescence emission spectra of 1 in methanol upon addition of Mg 2+ ion (λex = 362 nm).
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Fig. S12 Fluorescence emission spectra of 1 in methanol upon addition of Mn2+ ion (λex = 362 nm).
Fig. S13 Fluorescence emission spectra of 1 in methanol upon addition of Na+ ion (λex = 362 nm).
Fig. S14 Fluorescence emission spectra of 1 in methanol upon addition of Ni2+ ion (λex = 362 nm).
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3. Fluorescence Decay Curves of 1 in Methanol before, after Addition of Zn2+ and Cu2+.
Fig. S15 Fluorescence decay curve of 1 (2.5 × 10−5 M) in methanol.
Fig. S16 Fluorescence decay curve of 2 × 10−5 M solution of 1 in methanol after addition of 2 equiv Zn2+.
Fig. S17 Fluorescence decay curve of 2 × 10−5 M solution of 1 in methanol after addition of 2 equiv Cu2+.
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4. X-ray Crystallography
Intensity data collection was carried out with a Bruker APEXII diffractometer equipped with a CCD detector using Mo
Kα monochromatized radiation ( = 0.71073Å) at room temperature. The raw frame data were integrated into SHELX-
format reflection files and corrected for Lorentz and polarization effects using SAINT [1]. Corrections for incident and
diffracted beam absorption effects were applied using SADABS [1]. The structure was solved by direct method and
refined by full-matrix least-squares method on F2 using the SHELXTL 97 software package [2]. All non-hydrogen
atoms were refined anisotropically. Positions of hydrogen atoms attached to carbon atoms were fixed at their ideal
positions, and those attached to oxygen atoms could not be located.
Table 1. Crystallographic Data for 1
1
Empirical formula
Formula weight
C26H26N4O4
452.48
Crystal size [mm]
T/K
0.26×0.24×0.22
292
crystal system
space group
a/Å
b/Å
c/Å
Monoclinic
P 2/c
7.975(1)
16.447(2)
19.293(3)
90
99.295(9)
90
2497.4(5)
4
α/deg
β/deg
γ/deg
V/Å3
Z
ρ
calcd/g cm-3
1.209
968
F(000)
Reflections collected
Unique reflections
Rint
5843
4413
0.0556
1.531
GOF(S)
data/restraints/paras
Final R indices
I > 2σ(I)
2570/0/188
0.0882
0.1607
R indices
all data
R1=0.1867
wR2=0.2051
X-ray crystal structures of 1, solvent molecules were deleted for clarity.
[1] Bruker Analytical X-ray Systems, Inc.: Madison, WI, 1998.
[2] G. M. Sheldrick, SHLEXL97, Program for Crystal Structure Refinement, University of Göttingen, Germany, 1997.
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Table 2. Crystallographic Data for 5-Zn
5-Zn
Empirical formula
Formula weight
Crystal size [mm]
T/K
C72H72Cl8N24Zn4
1818.68
0.22×0.20×0.16
294
crystal system
space group
a/Å
b/Å
c/Å
Triclinic
P -1
9.414(2)
13.961(3)
16.640(3)
90.71(2)
99.74(3)
109.21(3)
2030.0(8)
4
α/deg
β/deg
γ/deg
V/Å3
Z
ρ
calcd/g cm-3
1.486
928
F(000)
Reflections collected
Unique reflections
Rint
10772
7849
0.0246
1.079
GOF(S)
data/restraints/paras
Final R indices
I > 2σ(I)
10772/0/491
0.0542
0.1109
R indices
all data
R1=0.0816
wR2=0.1323
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