Fluorescence Turn-on Chemosensor for Detection of Trivalent Chromium Ions
Scheme 1 The synthetic route of NPQ-C
thalic anhydride (5 g, 18 mmol), 1-aminobutane (1.7 g,
23.3 mmol) in 40 mL acetic acid was stirred under re-
flux in a nitrogen atmosphere for 6 h. After the comple-
tion of reaction, the reaction mixture was then poured
into a mixture of cracked ice and water (200 mL) and
filtered to get a pale yellow solid. The crude product
was recrystallized from chlorobenzene to give 4.6 g
CH2Cl2, r.t.
Br
N
+
Br
HN
N
O
Br
NH2
O
1
1
light gray solid in a yield of 85%. H NMR (CDCl3) δ:
8.64 (d, J=7.2 Hz, 1H), 8.53—8.55 (m, 1H), 8.39 (d,
J=7.6 Hz, 1H), 8.02 (d, J=8.0 Hz, 1H), 7.81—7.85 (m,
1H), 4.17 (t, J=7.6 Hz, 2H), 1.67—1.75 (m, 2H),
1.40—1.49 (m, 2H), 0.98 (t, J=7.2 Hz, 3H).
O
O
O
O
N
O
H2N
Compound 3 4-Brom-N-n-buty-1-naphthalimide
(954 mg, 3 mmol) and piperazine (1810 mg, 21 mmol)
were dissolved in 2-methoxyethanol (18 mL), and the
reaction mixture was refluxed for 6 h under N2 atmos-
phere. After removal of 2-methoxyethanol under re-
duced pressure, the product was then chromatographed
on silica gel using dichloromethane/methanol (10∶1,
V/V) as eluant to afford 830 mg (82%) 2 as yellow solid.
1H NMR (CDCl3) δ: 8.57 (d, J=7.2 Hz, 1H), 8.51 (d,
J=8.4 Hz, 1H), 8.41 (d, J=8.4 Hz, 1H), 7.68 (t, J=7.6
Hz, 1H), 7.21 (d, J=8.0 Hz, 1H), 4.16 (t, J=7.6 Hz,
2H), 3.19—3.24 (m, 8H), 1.74—1.79 (m, 3H), 1.67—
1.73 (m, 2H), 1.41—1.47 (m, 2H), 0.97 (t, J=7.2 Hz,
3H).
CH3COOH, reflux
Br
Br
2
H
N
O
N
O
N
H
CH3OCH2CH2OH, reflux
N
N
H
NPQ-C A mixture of 3 (150 mg, 0.4 mmol), 1
(300 mg, 1.2 mmol), K2CO3 (413 mg, 3 mmol), and KI
(50 mg, 0.3 mmol) in anhydrous CH3CN (15 mL) was
stirred at 60 ℃ for 4 h under an nitrogen atmosphere.
Subsequently, the solvent was removed under reduced
pressure, and the resulting residue was purified by silica
gel chromatography using methanol/CH2Cl2 (1∶100)
3
O
N
O
1
1
K2CO3, KI, CH3CN, reflux
as eluent to afford a yellow solid (110 mg, 25%). H
N
NMR (CDCl3) δ: 11.48 (s, 1H), 8.84—8.86 (m, 1H),
8.78—8.80 (m, 1H), 8.55—8.60 (m, 2H), 8.43 (d, J=
8.4 Hz, 1H), 8.15—8.18 (m, 1H), 7.69—7.72 (m, 1H),
7.52—7.58 (m, 2H), 7.44—7.47 (m, 1H), 7.30—7.32
(m, 1H), 4.18 (t, J=7.2 Hz, 2H), 3.46—3.50 (m, 6H),
3.05—3.06 (m, 4H), 1.40—1.50 (m, 2H), 1.25—1.28
(m, 2H), 0.98 (t, J=7.2 Hz, 3H); 13C NMR (CDCl3) δ:
168.05, 164.47, 164.05, 155.77, 148.61, 139.00, 136.28,
134.19, 132.47, 131.15, 130.15, 129.88, 128.07, 127.34,
126.20, 125.82, 123.35, 121.90, 121.63, 117.05, 116.65,
114.99, 62.42, 53.50, 53.35, 40.13, 30.28, 29.70, 20.42,
13.89. MS m/z: 522.2427 [M+H]+ (calcd 522.2430
[M+H]+).
N
H
N
O
N
NPQ-C
Compound 1 A solution of 8-aminoquinoline
(0.72 g, 5 mmol) in CH2Cl2 (25 mL) and triethylamine
(0.505 g, 5 mmol) was cooled in an ice bath. Bromo-
acetyl bromide (1.20 g, 5.5 mmol) dissolved in CH2Cl2
(10 mL) was added dropwise over 10 min with stirring.
Upon stirring at ambient temperature for 4 h, the reac-
tion mixture was washed successively with 0.3 mol•L-
1
The metal salts used
HCl (30 mL) and the organic layer was extracted and
rotary-evaporated. The resultant oil was purified by
chromatography on a silica gel column using ethyl ace-
tate-hexanes (V/V=1∶2) as eluent. The product was
obtained as a yellow solid by removal of the solvent.
Yield: 90% (1.18 g). 1H NMR (CDCl3) δ: 10.91 (s, 1H),
8.74—8.76 (m, 1H), 8.16—8.18 (m, 1H), 7.55—7.56
(m, 2H), 7.46—7.49 (m, 1H), 4.31 (s, 2H).
Fe2(SO4)3•9H2O, ZnSO4•6H2O, Co(ClO4)2•6H2O,
NiSO4•6H2O, Ca(ClO4)2, Cr(ClO4)3•6H2O, CuSO4•
5H2O, Mn(ClO4)2•6H2O, Na2SO4•10H2O, K2SO4,
AgClO4•H2O, Hg(ClO4)2•3H2O, Cd(ClO4)2•6H2O.
Results and Discussion
The interaction of sensor NPQ-C with the cations
Compound 2 A mixture of 4-bromo-1,8-naph-
was investigated through fluorescence spectra. All the
Chin. J. Chem. 2012, 30, 2844—2848
© 2012 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
2845