J. Ma et al.
Dyes and Pigments 188 (2021) 109225
7.94 (d, 1H, J = 7.9 Hz), 7.84 (s, 1H),7.74 (d, 1H, J = 2.0 Hz), 7.53 (t,
1H, J = 7.2 Hz), 7.44 (t, 1H, J = 7.2 Hz), 7.15 (d, 1H, J = 7.5 Hz), 4.66 (t,
2H, J = 6.6 Hz), 4.15–4.04 (m, 4H), 3.74–3.71 (m, 2H), 2.57–2.53 (m,
2H), 1.95–1.86 (m, 2H), 1.38–1.28 (m, 16H), 0.93–0.86 (m, 12H). 13C
NMR (150 MHz, CDCl3): 168.84, 166.46, 163.53, 163.07, 157.95,
151.93, 151.58, 147.12, 132.57, 131.38, 130.07, 129.16, 127.87,
126.81, 126.03, 125.73, 125.28, 124.82, 123.50, 122.19, 121.55,
119.39, 119.34, 119.03, 118.34, 116.86, 100.37, 47.77, 44.49, 43.91,
40.12, 37.78, 30.72, 29.86, 28.68, 28.64, 24.03, 23.04, 14.11, 10.69.
MALDI-HRMS: m/z calcd for [C48H53N7O5S–H]- 839.3823; found:
839.3814.
2.2.5. Synthesis of compound N-5
Under Ar atmosphere, 7 (43.0 mg, 0.06 mmol) and 8 (15.0 mg, 0.06
mmol) were dissolved in the mixed solvent (14 mL, CHCl3: EtOH: H2O =
12 : 1: 1, v/v). Then CuSO4⋅5H2O (4.5 mg) and sodium ascorbate (7.2
mg) was added respectively. The resulting mixture was stirred at 35 ◦C
for 48 h. Then the reaction mixture was washed with brine and extracted
with CH2Cl2. Organic layer was dried over anhydrous Na2SO4 and
evaporated under reduced pressure. The crude product was purified by
column chromatography (silica gel, CH2Cl2: CH3OH = 100 : 1, v/v) to
1
give purple solid. Yield: 50 mg, 86.2%. H NMR (400 MHz, CDCl3): δ
12.71 (s, 1H), 9.45–9.39 (m, 2H), 8.17 (s, 1H), 8.10 (s, 1H), 8.06 (s, 1H),
8.00 (d, 1H, J = 8.1 Hz), 7.92 (d, 1H, J = 7.9 Hz), 7.84 (s, 1H), 7.73 (d,
1H, J = 8.2 Hz), 7.52 (t, 1H, J = 7.2 Hz), 7.43 (t, 1H, J = 7.3 Hz), 7.13 (d,
1H, J = 8.5 Hz), 4.64 (t, 2H, J = 6.6 Hz), 4.11–4.05 (m, 4H), 3.64–3.60
(m, 2H), 3.36 (t, 1H, J = 5.7 Hz), 2.53–2.49 (m, 2H), 1.77–1.71 (m, 1H),
1.53–1.48 (m, 2H), 1.45–1.43 (m, 2H), 1.37–1.28 (m, 20H), 0.98–0.86
(m, 18H). 13C NMR (150 MHz, CDCl3): 169.06, 169.03, 166.53, 166.30,
163.23, 163.17, 157.94, 151.66, 149.49, 148.42, 146.93, 132.68,
130.12, 126.73, 125.65, 125.56, 125.35, 122.34, 122.17, 121.57,
121.28, 120.85, 118.79, 118.33, 117.37, 116.92, 102.44, 101.35, 48.01,
46.36, 43.96, 40.01, 39,17, 37.85, 31.21, 30.78, 29.76, 28.85, 28.82,
28.70, 28.86, 24.56, 24.07, 23.13, 23.02, 14.12, 10,98, 10.63. MALDI-
HRMS: m/z calcd for [C56H70N8O5S–H]- 966.5184; found: 966.5174.
Fig. 1. UV–vis absorption of N-1~N-5. c = 1.0 × 10ꢀ 5 M in PhCH3, 20 ◦C.
(t, 2H, J = 7.8 Hz), 2.03–1.93 (m, 2H), 1.82–1.78 (m, 1H), 1.55–1.30 (m,
24H), 1.01–0.88 (m, 18H). 13C NMR (150 MHz, CDCl3): 167.91, 165.78,
162.36, 162.08, 161.48, 158.12, 151.51, 150.96, 136.41, 135.96,
132.12, 131.85, 126.89, 126.24, 125.23, 124.35, 121.89, 121.64,
121.05, 120.12, 119.34, 117.77, 116.24, 114.03, 99.44, 97.05, 88.60,
46.00, 44.04, 43.31, 38.79, 37.39, 37.25, 30.65, 30,18, 29.17, 28.33,
28.14, 24.03, 23.63, 23.53, 22.67, 22.61, 22.52, 13.55, 10.45, 10.22.
MALDI-HRMS: m/z calcd for [C38H54BrN3O4 + H ]+ 867.4514; found:
867.4525.
2.2.3. Synthesis of compound N-3
3. Results and discussion
N-3 was obtained according to the following the procedure similar to
that of N-1, except 9 (30 mg, 0.13 mmol) was used instead of 8. Orange
solid (35 mg), yield: 42.4% [1]. H NMR (600 MHz, CDCl3): δ 8.92 (d, 1H,
J = 2.1 Hz), 8.86 (s, 1H), 8.76 (d, 1H, J = 7.6 Hz), 8.69 (d, 1H, J = 7.6
Hz), 8.14 (d, 1H, J = 8.1 Hz), 7.97 (d, 1H, J = 7.8 Hz), 7.85 (m, 1H), 7.85
(m, 1H), 7.53 (t, 1H, J = 7.2 Hz), 7.41 (t, 1H, J = 7.2 Hz), 7.11 (d, 1H, J
= 8.6 Hz), 4.29 (t, 2H, J = 6.5 Hz), 4.24–4.09 (m, 4H), 2.08–2.02 (m,
3H), 1.96–1.91 (m, 1H), 1.71–1.64 (m, 2H), 1.43–1.31 (m, 16H), 1.08 (t,
3H, J = 7.3 Hz), 0.99–0.88 (m, 12H). 13C NMR (150 MHz, CDCl3):
162.00, 162.80, 162.58, 161.65, 161.61, 161.24, 161.18, 157.47,
151.89, 136.84, 136.11, 135.91, 133.75, 130.91, 130.03, 127.70,
127.38, 126.05, 125.30, 125.13, 124.95, 124.83, 123.04, 122.27,
122.20, 121.22, 115.20, 112.22, 111.76, 102.71, 89.79, 69.43, 44.53,
37.89, 31.18, 30.72, 28.64, 24.04, 23.06, 19.54, 14.16, 14.12, 13.94,
10.67. MALDI-HRMS: m/z calcd for [C49H53N3O5S–H]- 795.3700;
found: 795.3713.
3.1. Design and synthesis
We prepared the dyes (N-1 and N-2) of NDI conjugated with HBT by
Pd (0) catalyzed Sonogashira coupling reaction. The acetylenic bond
–
–
(-C C-) linker was introduced into the molecules. With introduction of
–
alkylamino group into NDI core, N-2 was prepared to access larger ab-
sorption compared with N-1. In order to compare the difference of the
conjugation and non-conjugation structures, we also prepared the dyads
(N-4 and N-5) by click reaction catalyzed by Cu(0). The key procedure is
that bromo-atom in NDI is substituted by 3-azidopropan-1-amine. All
the compounds were obtained in moderate to satisfying yields. (see
experimental section and ESI† for details). The synthetic route was
described in Scheme 1.
3.2. Uv–vis absorption and fluorescence emission spectrums
2.2.4. Synthesis of compound N-4
The UV–Vis absorption spectra of the compounds (N-1~N-5) were
studied (Fig. 1). The absorption band at about 300–320 nm is probably
attributed to the enol-form of HBT moieties. The absorption maximums
of all the compounds are not very sensitive to solvent polarity, which
suggested proton transfer process doesn’t occur in the ground state. N-1
Under Ar atmosphere, 6 (50.0 mg, 0.085 mmol) and 8 (30.0 mg,
0.12 mmol) were dissolved in the mixed solvent (14 mL, CHCl3:EtOH:
H2O = 12:1:1, v/v). Then CuSO4⋅5H2O (4.5 mg) and sodium ascorbate
(7.2 mg) was added respectively. The resulting mixture was stirred at
35 ◦C for 24 h. Then the reaction mixture was washed with brine and
extracted with CH2Cl2. Organic layer was dried over anhydrous Na2SO4
and evaporated under reduced pressure. The crude product was purified
by column chromatography (silica gel, CH2Cl2: CH3OH = 100 : 1, v/v) to
give red solid. Yield: 48 mg, 67.3%. 1H NMR (400 MHz, CDCl3): δ 12.71
(s, 1H), 10.22 (t, 1H, J = 7.8 Hz), 8.64 (d, 1H, J = 7.8 Hz), 8.35 (d, 1H, J
= 7.8 Hz), 8.20 (d, 1H, J = 1.9 Hz), 8.17 (s, 1H), 8.02 (d, 1H, J = 8.1 Hz),
gives the absorption maximum at 483 nm in toluene (
ε = 16900
Mꢀ 1cmꢀ 1). Compared to N-1, stronger absorption band of N-2 shows
dramatically red-shift (λ = 560 nm,
ε
= 22500 Mꢀ 1cmꢀ 1) due to the
abs
substitution of alkylamino group [33].
By click reaction, the compounds of non-conjugation with HBT (N-4
and N-5) were also studied [46,47]. With introduction of one or two
alkylamino groups, absorption bands of N-4 and N-5 move to 515 and
3