Journal of Materials Chemistry C
Paper
Experimental
4-(2,5-Dimethylbenzo[d]thiazol-3-ium-3-yl)butane-1-sulfonate
(2d). Yield 97%. H-NMR (500 MHz, DMSO-d6, d (ppm)): 1.75–
1
All the solvents used in the present work were commercially
available (HPLC grade). The starting materials 1a, 1b, 2a, and
2b were commercially available and were used as supplied. The
melting points were determined on a Kofler apparatus and are
uncorrected. The NMR spectra of the samples in DMSO-d6,
were obtained on a Bruker Avance III 500 DRX 600 MHz
1.77 m (2H, CH2), 1.79–1.97 m (2H, CH2), 2.57 t (2H, J3 HH =
7.2 Hz, CH2SO3ꢁ), 3.23 s (3H, CH3), 3.26 s (3H, CH3), 4.67 t (2H,
J3 HH = 8.1 Hz, CH2N+), 7.62 d (1H, J3 HH = 6.5 Hz, Ar),
8.25–8.27 m (2H, Ar).
spectrometer. The MALDI-TOF/TOF spectra were measured on Synthesis of N-phenylaza-15-crown-5 (2g)
a Bruker rapifleX platform at the MPIP, Mainz, Germany. The
In a 500 ml three-neck round-bottom flask, equipped with an
electromagnetic stirrer, a reflux condenser and two dropping
funnels, solution of 1.81 (0.01 mol) of N-phenyl-
UV-VIS spectra were measured on a Unicam 530 UV–VIS spec-
trophotometer in conventional quartz cells of 1 cm path length.
The spectral bandwidth and the scan rate were Dl = 1 nm and
Dl = 140 nm minꢁ1, respectively. Stock solutions of each
compound were prepared in spectroscopic grade acetonitrile
(ACN) and all the experiments were carried out in red light
and at room temperature. Complex formation of dyes with
Ba(ClO4)2 was studied by spectrophotometric titration. In the
experiment aliquots of a solution containing known concentra-
tions of dyes and of Ba(ClO4)2 were added to a solution of dyes
alone at the same concentration. So, the absorption spectra
were recorded for solutions with identical total dye concen-
tration (1 ꢀ 10ꢁ5 M) and variable total Ba(ClO4)2 concentration
ranging from 1 ꢀ 10ꢁ5 M to 5 ꢀ 10ꢁ1 M in ACN. The emission
spectra were recorded on a HORIBA Jobin Yvon FluoroLog
3-221, spectrofluorometer with a Quanta-j accessory having a
large 150 mm integrating sphere for the quantum yield mea-
surements. All the spectra were recorded using quartz cells with
a 1 cm path length. The solution concentrations were chosen to
give an absorbance A r 0.05 at the excitation wavelengths of
l = 440 nm and l = 488 nm.
a
g
diethanolamine in 100 ml of THF and a solution of 4.59 g
(0.01 mol) of triethylene glycol ditosylate in 100 ml of THF were
added simultaneously, dropwise to a solution of 1 g of sodium
hydride, (NaH, 0.036 mol of 60% suspension) in 150 ml of THF
for 3 h. After the addition was completed, the reaction mixture
was refluxed for a further 4 h, cooled to room temperature and
then filtered. The filtrate was concentrated to dryness and
1.36 g (0.01 mol) of sodium perchlorate in 50 ml of methanol
was added, and the mixture was refluxed for 10 min. Ethyl
acetate (100 ml) was added and the mixture concentrated to a
10 ml volume. The resulting white precipitate was filtered off,
washed with ethyl acetate and dried. The yield was 70%, and
the Mp was 159–161 1C (literature: 156–159 1C). The complex
was destroyed by extraction with dichloromethane : water = 1 : 1.
The organic layer was dried with calcium dichloride
and evaporated to dryness. The Tm = 44–45 1C (literature:
44–45 1C).7
Synthesis of 4-aza-15-crown-5-benzaldehyde (3)
Synthesis of quaternary benzothiazolium salts 2a–2d
N-Phenylaza-15-crown-5 (2g) (2 g, 0.0068 mol) was dissolved in
6 ml of dimethylformamide (DMF). After cooling to ꢁ10 1C, the
amount of 1.04 g (0.62 ml, 0.0068 mol) phosphohenoxy chloride
were added dropwise and the reaction mixture was stirred for
1 h at room temperature and for 4 at 70 1C. The reaction
mixture was cooled and poured onto ice, then neutralized with
2 M sodium acetate and extracted with dichloromethane. The
extract was washed with water, dried with sodium sulfate and
concentrated to dry. The resulting oil was dissolved in 50 ml of
methanol, and 0.83 g (0.0068 mol) of sodium perchlorate was
added. The solution was refluxed for 10 min and concentrated
almost to dryness, and then 30 ml of ethyl acetate was added.
The obtained precipitate was filtered off and dried. The alde-
hyde sodium complex was developed as described previously.
Yield 67%. Tm = 85–87 1C (literature: 86–87 1C8). 1H-NMR
(500 MHz, CDCl3, TMS, d (ppm)): 3.52–3.72 m (16H, CH2O),
3.78–3.80 t (4H, NCH2), 6.71 d (2H, J3HH = 8.7 Hz, Ar), 7.70 d
(2H, J3HH = 8.5 Hz, Ar), 9.73 s (1H, CHO).
The appropriate 2-methylbenzothiazole 1a or 1b (0.01 mol) and
0.01 mol of 1,3-propane sultone (1c) or 0.01 mol 1,4-butane
sultone (1d) were dissolved in 3 ml of NMP and heated in an
argon atmosphere at 145 1C for 3 h. After cooling to room
temperature, the reaction work-up was performed as has
already been described.5
3-(2-Methylbenzo[d]thiazol-3-ium-3-yl)propane-1-sulfonate
(2a). Yield 93%. 1H-NMR (500 MHz, DMSO-d6, d (ppm)):
2.16–2.19 m (2H, CH2), 2.65 t (2H, J3 HH = 6.6 Hz, CH2SO3ꢁ),
3.21 s (3H, CH3), 4.93 t (2H, J3 HH = 8.1 Hz, CH2N+),
7.78–7.82 m (1H, Ar), 7.88–7.91 m (1H, Ar), 8.44 d (1H,
J3 HH = 8.8 Hz, Ar), 8.46 d (1H, J3 HH = 8.7 Hz, Ar).
3-(2,5-Dimethylbenzo[d]thiazol-3-ium-3-yl)propane-1-sulfonate
(2b). Yield: 94%. 1H-NMR (500 MHz, DMSO-d6, d (ppm)): 2.09–
2.16 m (2H, CH2), 2.4 t (2H, J3 HH = 6.3 Hz, CH2SO3ꢁ), 2.51 s
(3H, CH3), 2.65 s (3H, CH3), 4.87 t (2H, J3 HH = 8.0 Hz, CH2N+),
7.64 s (1H, Ar), 8.25–8.29 m (2H, Ar).
4-(2-Methylbenzo[d]thiazol-3-ium-3-yl)butane-1-sulfonate
(2c). Yield 93%. 1H-NMR (500 MHz, DMSO-d6, d (ppm)):
1.75–1.83 m (2H, CH2), 1.95–2.02 m (2H, CH2), 2.54 t (2H,
J3 HH = 7.2 Hz, CH2SO3ꢁ), 3.23 s (3H, CH3), 4.75 t (2H, J3 HH =
8.1 Hz, CH2N+), 7.78–7.82 m (1H, Ar), 7.88–7.91 m (1H, Ar),
8.42–8.44 m (2H, Ar).
Synthesis of dyes 4a–4d
The dyes 4a–4d were prepared by a previously described
procedure.5 All the analytical data completely corresponded to
that already published.
This journal is © The Royal Society of Chemistry 2021
J. Mater. Chem. C, 2021, 9, 7119–7126 | 7125