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D. Guo et al. / Dyes and Pigments 98 (2013) 384e392
2.1.6. Trans-1-[p-(N,N-dimethylamino)styryl]-3-
methylimidozalium hexafluorophosphate (DIHFP)
2.1.12. Trans-1-[p-(N,N-dimethylamino)styryl]-3-
methylimidozalium 4-amino-1-naphthalenesulfonate (DIANS)
1H NMR (400 MHz, DMSO-d6)
J ¼ 8.2 Hz), 8.13 (s, 1H), 8.03e8.01 (d, 1H, J ¼ 8.2 Hz), 7.82 (s, 1H),
7.68e7.64 (m, 2H), 7.40e7.31 (m, 4H), 7.25e7.21 (d, 1H, J ¼ 14.5 Hz),
6.76e6.73 (d, 2H, J ¼ 8.8 Hz), 6.52e6.50 (d, 1H, J ¼ 7.9 Hz), 5.79 (s,
2H), 3.89 (s, 3H), 2.95 (s, 6H). 13C NMR (400 MHz, DMSO-d6)
1H NMR (400 MHz, DMSO-d6)
d
¼ 9.33 (s, 1H), 8.14 (t, 1H,
d
¼ 9.35 (s, 1H), 8.73 (d, 1H,
J ¼ 1.4 Hz), 7.83 (s, 1H), 7.70e7.66 (d, 1H, J ¼ 14.5 Hz), 7.40e7.37 (d,
2H, J ¼ 8.8 Hz), 7.25e7.21 (d, 1H, J ¼ 14.5 Hz), 6.77e6.75 (d, 2H,
J ¼ 8.8 Hz), 3.89 (s, 3H), 2.96 (s, 6H). 13C NMR (400 MHz, DMSO-d6)
d
¼ 36.5, 112.6, 118.1, 119.7, 120.6, 124.7, 125.1, 128.5, 135.4, 151.2.
Calcd for C14H18F6N3P: C, 45.05; H, 4.86; N, 11.26%. Found: C, 44.9;
H, 4.63; N, 11.07%.
d
¼ 36.5, 105.4, 112.6, 118.1, 119.8, 120.6, 122.4, 123.1, 123.7, 124.7,
125.1, 125.4, 126.5, 128.3, 128.5, 130.8, 132.8, 135.4, 146.1, 151.2.
2.1.7. Trans-1-[p-(N,N-dimethylamino)styryl]-3-
methylimidozalium 1-naphthalenesulfonate (DINS-1)
2.2. X-ray crystal structure analysis
1H NMR (400 MHz, DMSO-d6)
d
¼ 9.34 (s, 1H), 8.86e8.84 (m,
Single crystal X-ray analysis was carried out on a Bruker SMART
APEX-II equipped with CCD area-detector diffractometer at 296 K
using graphite-monochromated Mo K
with the f and w scans method. The structures were solved by direct
methods and refined by full-matrix least-squares technique on F2
using SHELX programs. The crystallographic data of all crystals
have been deposited in the Cambridge Crystal-lographic Data
centre.
1H), 8.13 (t, 1H, J ¼ 1.6 Hz), 7.95e7.93 (m, 1H), 7.90e7.86 (m, 2H),
7.82 (s, 1H), 7.68e7.64 (d, 1H, J ¼ 14.5 Hz), 7.50e7.47 (m, 2H), 7.44e
7.40 (m, 1H), 7.39e7.37 (d, 2H, J ¼ 8.8 Hz), 7.25e7.21 (d, 1H,
J ¼ 14.5 Hz), 6.76e6.74 (d, 2H, J ¼ 8.8 Hz), 3.89 (s, 3H), 2.95 (s, 6H).
ꢀ
a
radiation (
l
¼ 0.71073 A)
13C NMR (400 MHz, DMSO-d6)
124.7, 124.8, 124.9, 125.0, 125.9, 128.1, 128.2, 128.5, 129.5, 129.8,
133.9, 135.4, 144.5, 151.2.
d
¼ 36.5, 112.6, 118.1, 119.7, 120.6,
2.1.8. Trans-1-[p-(N,N-dimethylamino)styryl]-3-
methylimidozalium mesitylenesulfonate (DITMS)
2.3. Powder SHG test
1H NMR (400 MHz, DMSO-d6, 313K)
d
¼ 9.35 (s, 1H), 8.11 (s, 1H),
The SHG measurements of DITMS and DINS-1(II) were per-
formed on a modified KurtzeNLO [42] system. The powder sam-
ple’s SHG efficiency has been shown to depend strongly on particle
size, so, polycrystalline samples of DINS-1(II), DITMS and DAST
were ground and sieved into distinct grain size ranges (40e49, 50e
59, 60e74, 75e84, 85e99, 100e124, 125e149, 150e199 and 200e
7.80 (s, 1H), 7.65-7.62 (d, 1H, J ¼ 14.5 Hz), 7.39e7.37 (d, 2H,
J ¼ 8.8 Hz), 7.24e7.20 (d, 1H, J ¼ 14.5 Hz), 6.76e6.74 (d, 2H,
J ¼ 8.8 Hz), 6.73 (s, 2H), 3.90 (s, 3H), 2.95 (s, 6H), 2.50 (s, 6H), 2.16 (s,
3H). 13C NMR (400 MHz, DMSO-d6)
119.8, 120.7, 124.7, 124.9, 128.5, 130.3, 135.4, 136.3, 136.7, 143.3,
151.2.
d
¼ 20.7, 23.2, 36.5, 112.6, 118.1,
299 mm). The sieved DAST powders of the same size ranges were
used as reference. The samples were pressed between glass mi-
croscope cover slides and secured with tape in 0.45 mm thick
aluminium holders containing a 3 mm diameter hole. Then they
were placed in a light-tight box and irradiated with a pulsed
infrared beam of wavelength 2100 nm, which is pumped from a Q-
switched CrTmHo: YAG laser. A cut-off filter was used to limit
background flash-lamp light on the samples and an interference
filter (1050 ꢀ 10 nm) was used to select the second harmonic for
detection with a photomultiplier tube attached to a Tektronix 4000
500-MHz oscilloscope.
2.1.9. Trans-1-[p-(N,N-dimethylamino)styryl]-3-
methylimidozalium 2-naphthalenesulfonate (DINS-2)
1H NMR (400 MHz, DMSO-d6)
d
¼ 9.33 (s, 1H), 8.14 (t, 2H,
J ¼ 1.7 Hz), 7.98e7.96 (m, 1H), 7.91e7.85 (m, 2H), 7.84e7.83 (t, 1H,
J ¼ 1.5 Hz), 7.72e7.66 (m, 2H), 7.54e7.51 (m, 2H), 7.39e7.37 (d, 2H,
J ¼ 8.8 Hz), 7.25e7.22 (d, 1H, J ¼ 14.5 Hz), 6.76e6.74 (d, 2H,
J ¼ 8.8 Hz), 3.9 (s, 3H), 2.95 (s, 6H). 13C NMR (400 MHz, DMSO-d6)
d
¼ 36.5, 112.6, 118.1, 119.7, 120.6, 124.4, 124.5, 124.7, 125.0, 126.7,
126.9, 127.7, 127.9, 128.5, 128.9, 132.6, 133.2, 135.4, 146.1, 151.2. Calcd
for C24H25N3O3S: C, 61.13; H, 5.30; N, 8.91; S, 6.80%. Found: C, 61.43;
H, 5.26; N, 8.65; S, 6.77%.
3. Results and discussion
2.1.10. Trans-1-[p-(N,N-dimethylamino)styryl]-3-
methylimidozalium tetraphenylborate (DITPB)
3.1. Synthesis of imidozolium salts
1H NMR (400 MHz, DMSO-d6)
d
¼ 9.34 (s, 1H), 8.14 (t, 1H,
The chemical structures of the imidazolium salts designed as well
as the synthetic route are shown in Scheme 1. It is known that the
general synthesis routes of DAST and its analogues are through a
Knoevenagel reaction of 4-methyl-N-methylpyridinium salt and a
donor-substituted aromatic aldehyde. The hydrogen of methyl
group at position-4 of pyridinium is highly active, which makes
hydrogen easily leave from the carbon atom to create a C]C bond
[13]. However, for our system, the Knoevenagel reaction is not
effective in creating C]C bond when N,N-Dimethylbenzaldehyde
reacts with 1-methyl-3-methylimidazolium. The possible reason is
that the electron withdrawing activity of nitrogen cation in
position-3 of imidazolium is weaker than that in methyl substituted
pyridinium. Hence, we choose Heck reaction to synthesize the in-
termediate conjugated compound D1 as shown in Scheme 1. 4-Iodo-
N,N-dimethyl-Aniline reacts with 1-vinylimidazole smoothly under
the catalysis of palladium (II) acetate and tri-o-tolylphosphine [43e
45]. In addition, tetrabutyl ammonium bromide was added as a
phase transfer catalyst to get a homogeneous reaction. The yield of
D1 is about 20%. By contrast, the yield of the same reaction using
bromo-substituted aniline is less than 1%. Then D1 was transformed
J ¼ 1.5 Hz), 7.83 (s, 1H), 7.70e7.66 (d, 1H, J ¼ 14.5 Hz), 7.40e7.37 (d,
2H, J ¼ 8.7 Hz), 7.25e7.22 (d, 1H, J ¼ 14.5 Hz), 7.17 (m, 9H), 6.94e
6.90 (t, 7H, J ¼ 7.4 Hz), 6.80e6.75 (m, 6H), 3.89 (s, 3H), 2.96 (s, 6H).
13C NMR (400 MHz, DMSO-d6)
120.6, 121.9, 124.7, 125.2, 125.7, 125.8, 128.5, 135.4, 136.0, 151.3,
163.1, 163.6, 164.1, 164.6. Calcd for C38H38BN3: C, 83.36; H, 7.00; N,
7.67%. Found: C, 82.82; H, 6.82; N, 7.46%.
d
¼ 36.5, 56.9, 112.6, 118.1, 119.8,
2.1.11. Trans-1-[p-(N,N-dimethylamino)styryl]-3-
methylimidozalium diphenylamine-4-sulfonate (DIDAS)
1H NMR (400 MHz, DMSO-d6)
d
¼ 9.35(s,1H), 8.21 (s,1H), 8.13 (s,
1H), 7.82 (s, 1H), 7.68e7.65 (d, 1H, J ¼ 14.5 Hz), 7.46e7.43 (d, 2H,
J ¼ 8.5 Hz), 7.39e7.37 (d, 2H, J ¼ 8.8 Hz), 7.25e7.21 (t, 3H, J ¼ 7.3 Hz),
7.09e7.07 (d, 2H, J ¼ 7.8 Hz), 6.97e6.95 (d, 2H, J ¼ 8.5 Hz), 6.85e
6.81 (t,1H, J ¼ 7.3 Hz), 6.76e6.74 (d, 2H, J ¼ 8.8 Hz), 3.90 (s, 3H), 2.95
(s, 6H). 13C NMR (400 MHz, DMSO-d6)
d
¼ 36.5, 112.6, 115.5, 117.6,
118.1, 119.8, 120.4, 120.6, 124.7, 125.0, 127.2, 128.5, 129.6, 135.5,
140.4, 143.5, 143.9, 151.2. Calcd for C26H28N4O3S: C, 63.14; H, 6.11; N,
11.33; S, 6.48%. Found: C, 62.77; H, 6.13; N, 11.15; S, 6.74%.