9
1,3,6,8-Tetrakis(trimethylsilanylethynyl)pyrene (1)
. 1,3,6,8-
Conclusions
Tetrabromopyrene (0.25 g, 0.48 mmol) was suspended
in triethylamine (10 mL) and toluene (3 mL), and
In conclusion, we have demonstrated pyrene derivative 1 with
four TMS substituents as a colorimetric and fluorescence chemo-
dosimeter sensor for fluoride anions. This chemosensor shows a
very high sensitivity, a rapid response time and a high selectivity
for F-. Such significant spectroscopic changes in 1 upon the
addition of fluoride anions is attributed to the elimination of
the TMS substituents through a strong interaction between the
fluoride anion and the silicon atoms, which increases the energy
gap between the HOMO and LUMO due to the lack of s–p
interactions between the silicons and the pyrene. Moreover, test
papers have established the utility of 1 in monitoring fluoride
anions in water, indicating its potential application to detect and
estimate the concentration of fluoride anions in real-time.
bis(triphenylphosphine)palladium(II)
dichloride
(68
mg,
0.10 mmol), copper(I) iodide (36 mg, 0.19 mmol) and
triphenylphosphine (50 mg, 0.19 mmol) were added under
an argon atmosphere. While stirring, the reaction mixture was
heated to 60 ◦C and trimethylsilylethyne (0.28 g, 2.88 mmol)
injected. After 10 min, the reaction was heated to 80 ◦C and
stirred overnight. The cooled reaction mixture was diluted with
CH2Cl2 and washed with water. The organic phase was dried over
Na2SO4 and the solvent removed under reduced pressure. The
crude product was purified by column chromatography (silica gel,
1
hexane) to afford 1 as an orange solid (229 mg, 81%). H NMR
(400 MHz, CDCl3) d = 8.61 (m, 4 H, 4,5,9,10-pyrene-H), 8.32 (s, 2
H, 2,7-pyrene-H), 0.38 (s, 36 H, CH3); MS: m/z (%): 587.25 [M]+.
Experimental section
DFT calculations
Reagents and instruments
The G03W software package16 was used to carry out a DFT
geometry optimisation using the B3LYP functional with 6-31G(d)
basis sets. TD-DFT calculations were then carried out using the
same approach.
All reagents were obtained from commercial suppliers and
used without further purification, unless otherwise indicated.
Triethylamine was distilled over calcium hydride. Toluene was
1
dried over sodium metal and distilled. H NMR spectra were
recorded on a Bruker DPX400 spectrometer and referenced to
the residual proton signals of the solvent. Mass spectra were
measured on an Ion-Soec 4.7 T HiRes MALDI instrument.
UV-vis absorption spectra were acquired on a scinco S-3150
UV-vis spectrophotometer. Fluorescence spectra were measured
on an Edinburgh LFS920 luminescence spectrophotometer (the
pathlength of the quartz cell was 1 cm) with a xenon arc lamp as
the light source.
Acknowledgements
We are thankful for financial support from the NSFC (nos.
20802014, 20903032, 20971066 and 21021062) and the innovation
teams for organosilicon chemistry (20091250016).
References
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Stock solutions of the anions (2 mM) were prepared with the
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Synthesis
9
1,3,6,8-Tetrabromopyrene . Bromine (16.0 g, 0.11 mol) was
added dropwise with vigorous stirring to a solution of pyrene
(5.0 g, 0.025 mol) in nitrobenzene (100 mL) at 120 ◦C. The mixture
was kept at 120 ◦C for 4 h and then cooled to room temperature
to yield a pale green precipitate. This was filtered, washed with
ethanol (100 mL) and dried under vacuum. The solid product was
obtained with 92% yield.
This journal is
The Royal Society of Chemistry 2011
Org. Biomol. Chem., 2011, 9, 4558–4562 | 4561
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