Page 7 of 9
Journal Name
Physical Chemistry Chemical Physics
DOI: 10.1039/C4CP05829A
13C NMR (100 MHz, Acetone) δ 179.72, 156.06, 148.25, In a similar manner described above, chromophore y3 was
147.96, 146.26, 145.75, 137.31, 131.05, 128.97, 128.72, synthesized from 4c and acceptor 5, as a dark solid (40%).
125.07, 121.23, 112.14, 111.10, 110.93, 74.29, 74.22, 44.04, 1H NMR (400 MHz, Acetone) δ 7.64 (d,
J
J
= 15.1 Hz, 1H), 7.13
= 8.7 Hz, 2H), 6.73
= 9.0 Hz, 2H), 6.18 (d, J=15.1 Hz
44.01, 31.60, 31.40, 30.03, 29.80, 25.86, 25.40, 22.55, 22.39, (d,
13.50, 13.42, 12.08, 12.00. (d,
J
J
= 9.0 Hz, 2H), 7.04 (s, 1H), 6.89 (d,
= 8.7 Hz, 2H), 6.57 (d,
J
MALDIꢀTOF: m/z calcd for C39H56N2O3S: 632.94 [M]+; 1H), 4.39 (m, 2H), 4.32 (m, 2H), 3.41 – 3.28 (m, 8H), 1.60 (s,
found:632.89.
3.2.5 Synthesis of chromophore y2
6H), 1.08 (m, 12H).
13C NMR (100 MHz, Acetone) δ 184.70, 176.72, 111.69,
A mixture of aldehydic bridge 4b (0.632 g, 1 mmol) and 111.08, 109.54, 104.58, 100.89, 97.14, 62.11, 62.04, 56.48,
acceptor 5 (0.24 g, 1.2 mmol) in ethanol (20 mL) in the 43.39, 43.34, 27.07, 25.87, 25.11, 25.03, 23.33, 16.15, 16.10,
presence of a catalytic amount of piperidine was stirred at 70 11.51.
°C for 3 h. After removal of the solvent, the residue was MALDIꢀTOF: m/z calcd for C40H41N5O3S: 671.85 [M]+;
purified by column chromatography on silica gel (hexane/ethyl found:672.12.
acetate, v/v, 5:1), a dark solid was obtained (0.27 g, 33%).
1H NMR (400 MHz, Acetone) δ 7.91 (d,
J
= 15.6 Hz, 1H), 7.30
= 8.6 Hz, 2H), 6.85 (d,
= 9.0 Hz, 2H), 6.21 (d, = 15.6 Hz,
– 7.25 (m, 2H), 7.25 (s, 1H), 7.00 (d,
= 8.6 Hz, 2H), 6.69 (d,
J
J
Conclusions
J
J
In this research, a series of NLO chromophores based on
thiophene bridge bearing on different substituted groups with
the same bis(N,Nꢀdiethylaniline) donors and electron acceptor
(TCF) have been synthesized and systematically investigated
by NMR, MS and UVꢀvis absorption spectra. The energy gap
between ground state and excited state together with molecular
nonlinearity were studied by UVꢀvis absorption spectroscopy,
DFT calculations and CV measurements. Theoretical and
experimental investigations suggest that the isolation group
play a critical role in affecting the linear and nonlinear
properties of dipolar chromophores. In general, the energy gap
of y2 and y3chromophore is 1.03 and 1.02 eV respectively,
which is much lower than y1 chromophore without isolation
group on thiophene ring. These results confirmed that
chromophores with double donors and with different isolation
groups on the thiophene bridge exhibiting good thermal
stability and large molecular hyperpolarizabilities, which can be
effectively translated into very large EO coefficients in poled
polymers. The poling results of guestꢀhost EO polymers with
25 wt% of these chromophores showed that polymers with
chromophores y1ꢀ y3 afforded the large r33 values of 149, 139
and 125 pm/V respectively. Moreover, the stability of poled
APC/25% y1, y2 and y3 film could retain 78% ,81% and 76%
1H), 4.32 (m, 2H), 4.10 (m, 2H), 3.46 (m, 8H), 1.88 – 1.76 (m,
4H), 1.73 (s, 6H), 1.54 (m, 4H), 1.42 – 1.31 (m, 8H), 1.27 –
1.13 (m, 12H), 0.91 (m, 6H).
13C NMR (100 MHz, Acetone) δ 176.22, 172.76, 154.58,
148.20, 148.04, 147.82, 146.82, 139.35, 135.77, 131.60,
130.57, 129.27, 128.79, 120.15, 112.24, 111.57, 110.60,
110.36, 107.34, 96.31, 73.95, 73.43, 43.61, 43.53, 31.16, 30.77,
29.45, 25.17, 25.11, 25.01, 22.02, 21.86, 12.85, 11.57.
MALDIꢀTOF: m/z calcd for C50H66N5O3S: 814.13 [M]+;
found:814.75.
3.2.6 Synthesis of compound 2c
In a similar manner described above, 2c was synthesized from
1c as yellow solid (92%).
1H NMR (400 MHz, Acetone) δ 9.89 (d,
J
= 0.9 Hz, 1H), 7.03
(d,
J
= 0.9 Hz, 1H), 4.45 (dd,
J
= 5.2, 3.0 Hz, 2H), 4.34 (dd, J =
5.2, 3.0 Hz, 2H).
13C NMR (100 MHz, Acetone) δ 179.92, 149.97, 143.11,
118.97, 110.96, 66.47, 65.37.
MS (EI): m/z calcd for C7H6O3S: 170.19; found: 170.21.
3.2.7 Synthesis of compound 3c
In a similar manner described above, 3c was synthesized from
2c as yellow solid (74%).
1H NMR (400 MHz, Acetone) δ 7.15 (d,
J
= 9.0 Hz, 2H), 7.05
(s, 1H), 7.00 (d,
(d,
2H), 3.44 (m, 8H), 1.19 (m, 12H).
J = 8.7 Hz, 2H), 6.80 (d, J = 8.7 Hz, 2H), 6.65
= 9.0 Hz, 2H), 6.08 (s, 1H), 4.28 (m, 2H), 4.23 – 4.18 (m,
(100h) of the initial values at 85
℃
respectively.Those
J
consequences indicate that these chromophores with double
N,Nꢀdiethylaniline donors and isolated groups on the thiophene
bridge could efficiently reduce the interchromophore
electrostatic interactions and enhance the macroscopic optical
nonlinearity. These novel chromophores showed promising
applications in NLO chromophore synthesis. We believe that
these novel chromophores can be used in exploring highꢀ
performance organic EO and photorefractive materials where
both thermal stability and optical nonlinearity are of equal
importance.
13C NMR (100 MHz, Acetone) δ 147.84, 147.21, 141.40,
139.56, 138.63, 131.42, 130.22, 127.78, 126.48, 117.45,
112.27, 111.66, 111.51, 98.11, 64.90, 64.62, 44.07, 12.13,
12.08.
MALDIꢀTOF: m/z calcd for C28H34N2O2S: 462.65 [M]+;
found:462.61.
3.2.8 Synthesis of compound 4c
In a similar manner described above, 4c was synthesized from
3c as red solid (83%).
1H NMR (400 MHz, CDCl3) δ 9.70 (s, 1H), 7.24 (d,
J
J
= 8.8 Hz,
= 8.6 Hz,
Acknowledgements
We are grateful to the National Nature Science Foundation of
China (no. 61101054) for financial support.
2H), 7.06 (s, 1H), 7.03 (d,
2H), 6.58 (d,
J = 8.6 Hz, 2H), 6.72 (d,
J
= 8.8 Hz, 2H), 4.33 (m, 2H), 4.31 (m, 2H), 3.46
– 3.32 (m, 8H), 1.19 (m, 12H).
13C NMR (100 MHz, CDCl3) δ 178.26, 147.30, 146.89, 146.73,
144.66, 137.61, 130.14, 129.37, 128.15, 127.97, 123.94,
114.25, 111.20, 110.02, 109.37, 64.41, 63.52, 43.37, 43.33,
11.62.
Notes and references
a
Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and
Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China
b University of Chinese Academy of Sciences, Beijing 100043, PR China
* Corresponding authors. Tel.: +86-01-82543528; Fax: +86-01-62554670
MALDIꢀTOF: m/z calcd for C29H34N2O3S: 490.66 [M]+;
found:491.19.
.
3.2.9 Synthesis of chromophore y3
E-mail address: xinhouliu@foxmail.com and xhliu@mail.ipc.ac.cn (X. Liu)
This journal is © The Royal Society of Chemistry 2014
J. Name., 2014, 00, 1-3 | 7