Paper
Journal of Materials Chemistry C
Synthesis of N-butyl-4-phenylacetylene-1,8-naphthalimide (3a)
The synthesis was conducted according to the published references.
2 (1.00 g, 3.00 mmol), phenylacetylene (0.306 g, 3.00 mmol),
Pd(PPh3)2Cl2 (112 mg, 0.16 mmol), PPh3 (40 mg, 0.16 mmol),
CuI (32 mg, 0.16 mmol), and 2 mL of triethylamine were added
to anhydrous ethanol (50 mL). The reaction was stirred under
reflux for 12 h under the argon atmosphere, cooled to room
temperature, and then filtered to obtain the product. Subsequently,
the crude product was purified by chromatography on silica gel
using a hexane/EA (10 : 1) mixture as an eluent. A light yellow
solid was then obtained. Yield: 0.66 g (55%).
Scheme 1 Molecular structures of HPB, NPI-Ph, and NPI-Si.
1H NMR (CDCl3, 400 MHz, ppm): d 8.66 (d, 1H), 8.59 (d, 1H),
8.57 (d, 1H), 7.98 (d, 1H), 7.86 (d, 1H), 7.70 (m, 1H), 7.46 (m, 1H),
4.21 (t, 2H), 1.73–1.79 (m, 2H), 1.44–1.53 (m, 2H), 0.99 (m, 3H).
HRMS (FAB) calcd C24H19NO2 for [M + H]+ 354.1494, found
354.1273.
and sensitive fluorescence response to nitroaromatic explosives.
Interestingly, an unexpected SiMe3 effect was found in the two
dyes: the SiMe3-containing compound NPI-Si exhibited remark-
ably enhanced optical properties compared with the non-SiMe3
compound NPI-Ph such as a wider color-tunable range and
higher sensitivity for the fluorescence detection of nitroaromatic
explosives.
Synthesis of N-butyl-4-trimethylsilylethynyl-1,8-naphthalimide (3b)
The synthesis was performed according to the published references.
2 (1.00 g, 3.00 mmol), ethynyltrimethylsilane (0.306 g, 3.00 mmol),
Pd(PPh3)2Cl2 (112 mg, 0.16 mmol), PPh3 (40 mg, 0.16 mmol), CuI
(32 mg, 0.16 mmol), and 2 mL of triethylamine were added to
anhydrous ethanol (50 mL). The reaction was stirred under reflux
for 12 h under the argon atmosphere, cooled to room temperature,
and then filtered to obtain the product. The crude product was
then purified by chromatography on silica gel using a hexane/EA
(10 : 1) mixture as an eluent. A light yellow solid was then
obtained. Yield: 0.66 g (55%).
Experimental section
Material
4-Bromo-1,8-naphthalic anhydride, n-butylamine, phenylacety-
lene, Pd(PPh3)2Cl2, PPh3, CuI, triethylamine, and 2,3,4,5-tetra-
phenylcyclopenta-2,4-dienone were purchased from Aladdin
Industrial Company. Ethynyltrimethylsilane was obtained from
Beijing HWRK Chem. Co. LTD and used after fractionation
(Scheme 2).
1H NMR (CDCl3, 400 MHz, ppm): d 8.66 (d, 1H), 8.59 (d, 1H),
8.57 (d, 1H), 7.98 (d, 1H), 7.86 (d, 1H), 7.70 (m, 1H), 7.46 (m, 1H),
4.21 (t, 2H), 1.73–1.79 (m, 2H), 1.44–1.53 (m, 2H), 1.00 (m, 3H).
HRMS (FAB) calcd C21H23NO2Si for [M + H]+ 350.1576, found
350.1540.
Synthesis of N-butyl-4-bromo-1,8-naphthalimide (2)
The synthesis was performed according to the published references.
4-Bromo-1,8-naphthalic anhydride (1) (1.38 g, 5 mmol) and
n-butylamine (0.73 g, 10 mmol) were dissolved in 100 mL of
ethanol. The reaction mixture was stirred and refluxed for 5 h.
The crude product was obtained by filtration after the mixture
was cooled to room temperature. The crude product was then
purified by silica gel column chromatography using CH2Cl2/
hexane (2 : 1, v/v) as an eluent to afford a white solid product.
Yield: 1.22 g (70%).
Synthesis of N-butyl-4-pentaphenylbenzene-1,8-naphthalimide
(NPI-Ph)
3a (0.5 g, 1.42 mmol) and 2,3,4,5-tetraphenylcyclopenta-2,4-
dienone (0.54, 1.42 mmol) were added to 10 mL of diphenyl
ether. The reaction was stirred under reflux for 30 h under the
argon atmosphere and cooled to room temperature. The mixture
was then poured into 200 mL of methanol to obtain the crude
product. The crude product was purified by chromatography on
silica gel using a hexane/EA (10 : 1) mixture as an eluent. A light
yellow solid was then obtained. Yield: 0.63 g (62%).
1H NMR (CDCl3, 400 MHz, ppm): d 8.67 (d, 1H), 8.60 (d, 1H),
8.58 (d, 1H), 8.07 (d, 1H), 7.85–7.89 (m, 1H), 4.19 (t, 2H),
1.70–1.78 (m, 2H), 1.44–1.55 (m, 2H), 1.00 (t, 3H). HRMS (FAB)
calcd for C16H14BrNO2 [M + H]+ 332.0286, found 332.0027.
1H NMR (DMSO, 400 MHz, ppm): d 8.33 (d, 1H), 8.25 (d, 1H),
8.08 (d, 1H), 7.77 (m, 1H), 7.66 (d, 1H), 6.98–7.00 (m, 5H), 6.76–6.93
(m, 14H), 6.62–6.69 (m, 4H), 6.52 (m, 2H), 3.91 (t, 2H), 1.50–1.54
(m, 2H), 1.26–1.32 (m, 2H), 0.88 (m, 3H). 13C NMR (CDCl3, 400 MHz,
ppm): d 164.31, 164.22, 146.07, 141.64, 140.80, 140.74, 140.20,
139.96, 139.66, 136.56, 133.41, 131.33, 131.29, 130.83, 130.70,
130.59, 130.14, 129.58, 127.45, 126.75, 126.70, 126.63, 126.61,
125.83, 125.75, 125.48, 122.33, 120.71, 40.22, 30.20, 20.42, 13.85.
HRMS (FAB) calcd C52H39NO2 for [M + H]+ 710.3059, found
710.2901. Anal.calcd for C52H39NO2: C 87.98%, H 5.54%, N
1.97%, O 4.51%; found: C 87.91%, H 5.63%, N 2.01%, O 4.42%.
Scheme 2 The synthesis process of NPI-Ph and NPI-Si.
J. Mater. Chem. C
This journal is ©The Royal Society of Chemistry 2015