Molecules 2017, 22, 1741
11 of 14
◦
1
(
3.28 g) in a 20% yield; m.p.: 129–130 C; H-NMR (400 MHz, CDCl )
δ
(ppm): 8.87 (d, J = 8.8 Hz,
3
Ar-H, 1H), 8.52 (d, J = 7.2 Hz, Ar-H, 2H), 7.66 (t, J = 8.0 Hz, Ar-H, 1H), 7.38 (t, J = 8.0 Hz, Ar-H, 1H),
4
.14 (t, J = 7.2 Hz, CH , 2H), 3.87 (t, J = 5.2 Hz, CH , 4H), 3.63 (t, J = 5.2 Hz, CH , 4H), 2.81 (s, OH,
2 2 2
13
2H), 1.68–1.69 (m, CH , 2H), 1.43–1.45 (m, CH , 2H), 0.97 (t, J = 7.2 Hz, CH , 3H); C-NMR (100 MHz,
2 2 3
CDCl3)
δ (ppm): 164.34, 163.91, 154.28, 131.18, 131.22, 130.85, 130.14, 127.24, 125.65, 122.92, 117.18,
1
17.05, 59.73, 59.73, 55.33, 55.33, 40.10, 30.20, 20.38, and 13.85.
0 0
.5. Synthesis of N-n-Butyl-4-N ,N -diaminoethyl-1,8-naphthalimide (4)
3
0
0
N-n-butyl-4-N ,N -diaminoethyl-1,8-naphthalimide was prepared according to the reported
procedure [50]. Compound (2.0 g, 5.6 mmol), PPh (4.41 g, 16.8 mmol) and NaN (1.82 g, 28.0 mmol)
were dissolved in anhydrous N,N-dimethylformamide (100 mL), the solution was cooled to 0 C, and
2
3
3
◦
CBr (5.58 g, 16.8 mmol) was added portionwise over 10 min. Then, the reaction temperature was
4
raised to room temperature, and the mixture was stirred for 12 h. The reaction mixture was diluted
with water and extracted with ethyl acetate (4
×
50 mL). The organic layer was dried over anhydrous
Na SO and concentrated in vacuo. The crude compound was separated through silica gel column
2
4
chromatography and afforded compound
8.1 mmol) were dissolved in 50 mL of pyridine and kept at room temperature for 1 h. Concentrated
ammonium hydroxide (10 mL) was added, and the mixture was allowed to stand for an additional
h. Pyridine was removed through reduced pressure. Then, CH Cl and 1 N HCl were added to the
3. The compound 3 (1.9 g, 4.67 mmol) and PPh (7.36 g,
3
2
2
2
2
reaction mixture. The organic layer was washed with additional 1 N HCl, and the aqueous layers were
combined, neutralized with KOH, and extracted with CH Cl . The combined organic layers were
2
2
washed with water and brine and then dried over anhydrous Na SO to afford compound
6
4
(1.11 g,
(ppm): 8.74 (d, J = 0.3 Hz,
Ar-H, 1H), 8.43 (d, J = 7.8 Hz, Ar-H, 1H), 8.27 (d, J = 8.4 Hz, Ar-H, 1H), 7.68 (t, J = 8.1 Hz, Ar-H, 1H),
.81 (d, J = 8.4 Hz, Ar-H, 1H), 4.01 (t, J = 7.8 Hz, CH , 2H), 3.44–3.48 (m, CH , 2H), 2.87 (t, J = 5.7 Hz,
2
4
◦
7%) as a yellow solid; m.p.: 99–101 C; H-NMR (DMSO-d , 300 MHz) δ
6
1
6
2
2
CH , 2H), 2.65–2.72 (m, CH , 4H), 1.84 (s, NH , 4H), 1.54–1.62 (m, CH , 2H), 1.30–1.37 (m, CH , 2H),
2
2
2
2
2
+
and 0.92 (t, J = 7.5 Hz, CH , 3H). HRMS-ESI m/z: found 355.2123 for [M + H] and calculated 354.2056
3
for C H N O .
20
26
4
2
0 0 0 0
.6. Synthesis of N-n-Butyl-4-(1 -cyclooctene-1 ,3 ,6 -triazole)-1,8-naphthalimide (L)
3
0
0
0
0
N-n-butyl-4-(1 -cyclooctene-1 ,3 ,6 -triazole)-1,8-naphthalimide was obtained using a procedure
similar to that reported in the literature [40]. Benzoyl isothiocyanate (0.92 g, 5.6 mmol) was added
0
0
dropwise to a solution of N-n-butyl-4-N ,N -diaminoethyl-1,8-naphthalimide (1.0 g, 2.8 mmol) in
0 mL of ketone and was stirred at 45 C. The reaction mixture was stirred continuously for 45 min.
◦
3
After cooling, the solution was filtered, and the filter cake was washed with EtOH. The crude product
◦
was purified by chromatography to afford compound
L
(0.77 g, 57%) as a green solid; m.p.: 165–167 C;
1
H-NMR (CDCl , 300 MHz)
δ (ppm): 9.02 (s, NH, 1H), 8.29–8.42 (m, Ar-H, 4H), 7.54 (d, J = 6.6 Hz,
3
Ar-H, 1H), 7.46 (t, J = 7.5 Hz, Ar-H, 3H), 6.57 (d, J = 8.7 Hz, Ar-H, 2H), 4.12 (t, J = 7.5 Hz, CH , 4H),
2
3
.60–3.86 (m, CH , 4H), 3.55–3.61 (m, CH , 2H), 1.63–1.70 (m, CH , 2H), 1.38–1.45 (m, CH , 2H); 1.26 (s,
2
2
2
2
13
CNHC, 1H), 0.95 (t, J = 7.5 Hz, CH , 3H). C-NMR (75 MHz, CDCl3)
δ
(ppm): 164.72, 164.26, 164.26,
3
150.97, 150.97, 134.24, 134.24, 131.02, 131.02, 129.54, 129.54, 128.35, 128.35, 128.35, 128.35, 124.25, 122.59,
1
4
10.26, 103.13, 103.13, 45.86, 41.31, 41.24, 41.05, 39.93, 30.32, 20.44 and 13.88. HRMS-ESI m/z: found
+
84.2332 for [M + H] and calculated 483.5616 for C H N O .
28
29
5
3
4
. Conclusions
In summary, a new, rapidly responsive, colorimetric and “turn-off” fluorescent Cu sensor,
2+
0
0
0
0
N-n-butyl-4-(1 -cyclooctene-1 ,3 ,6 -triazole)-1,8-naphthalimide, was successfully synthesized and
characterized. Probe
2+
L exhibited a markedly quenched fluorescence in the presence of Cu with
a simultaneous color change (yellow to colorless) over a range of metal cations. The detection was
highly sensitive and more selective than some reported probes and almost unaffected by the common