Synthesis and properties of highly soluble third-order optically nonlinear chromophores and methacrylate monomer based on distyrylbenzene

Article abstract of DOI:10.1039/a803229g

A novel series of highly soluble distyrylbenzenes bearing poly(alkyleneoxy) and/or alkylsulfonyl solubilizing substituents has been synthesized using the stereoselective Wadsworth-Emmons reaction as a key step. The corresponding poly(alkyleneoxy) alkylsulfonyl 4,4′-disubstituted distyrylbenzene has been covalently incorporated into an acrylic monomer which has also been successfully co-polymerized with methyl methacrylate (MMA). All the 4,4′-disubstituted distyrylbenzenes and the polyacrylate based co-polymer show excellent solubility, processibility and thermal stability. Importantly, 2-(2-butoxyethoxy)ethoxy-hexylsulfonyl 4,4′-disubstituted distyrylbenzene exhibits only a minor bathochromic shift of the absorption maximum compared to those of the corresponding symmetrically 4,4′-disubstituted distyrylbenzenes; however, its third-order optical nonlinearity derived from Z-scan measurements at 800 nm is approximately twice as large as those of its symmetrically 4,4′-disubstituted counterparts.

Full text of DOI:10.1039/a803229g

J O U R N A L O F
Synthesis and properties of highly soluble third-order optically
nonlinear chromophores and methacrylate monomer based on
distyrylbenzene
M. S. Wong,*a,b† M. Samoc,a A. Samoc,a B. Luther-Daviesa and M. G. Humphreyb
C H E M I S T R Y
aAustralian Photonics Cooperative Research Centre, L aser Physics Centre, Research School of
Physical Sciences and Engineering, T he Australian National University, Canberra, ACT 0200,
Australia
bDepartment of Chemistry, T he Australian National University, Canberra, ACT 0200, Australia
A novel series of highly soluble distyrylbenzenes bearing poly(alkyleneoxy) and/or alkylsulfonyl solubilizing substituents has been
synthesized using the stereoselective Wadsworth–Emmons reaction as a key step. The corresponding poly(alkyleneoxy)
alkylsulfonyl 4,4∞-disubstituted distyrylbenzene has been covalently incorporated into an acrylic monomer which has also been
successfully co-polymerized with methyl methacrylate (MMA). All the 4,4∞-disubstituted distyrylbenzenes and the polyacrylate
based co-polymer show excellent solubility, processibility and thermal stability. Importantly, 2-(2-butoxyethoxy)ethoxy-
hexylsulfonyl 4,4∞-disubstituted distyrylbenzene exhibits only a minor bathochromic shift of the absorption maximum compared to
those of the corresponding symmetrically 4,4∞-disubstituted distyrylbenzenes; however, its third-order optical nonlinearity derived
from Z-scan measurements at 800 nm is approximately twice as large as those of its symmetrically 4,4∞-disubstituted counterparts.
Poly(phenylenevinylene) (PPV) is one of the widely
investigated p-conjugated polymeric materials exhibiting tech-
nologically useful multi-functional properties such as a large
third-order optical nonlinearity,1 an efficient electroluminesc-
ent response,2 a high conductivity upon doping and a laser
emission.4 Unsubstituted PPV is insoluble in organic solvents
and thin-films of this polymer are traditionally prepared by
spin-casting of a water soluble polysulfonium precursor fol-
lowed by pyrolysis.5,6 However, the polydispersity and the
poor structural perfection that are incurred in this preparation
procedure may affect the optical and electrochemical properties
of the polymeric thin-film. Over the last few years, various
soluble PPV derivatives and copolymers have been synthesized
to enhance the solubility and processibility as well as to tune
the desirable properties.7–9 With the solubilizing substituents
influencing the electronic properties of the PPV chain, e.g. via
induction and steric effects, and with the various compositions
of the copolymers, the physical properties of the PPV-based
materials are greatly varied. As a result, the exploration and
development of efficient and useful PPV-based materials for a
specific application still present a great challenge for the
scientific communities.
(non)linear optical and thermal properties of PPV-based mate-
rials are greatly dependent upon the degree of p-conjugation,
the co-planarity of the conjugated system and the electronic
properties of the substituents. Towards the goal of understand-
ing and establishing the structure–property relationship of
OPVs, we report here our initial studies on the synthesis of a
novel series of highly soluble three-phenyl-ring OPVs (distyryl-
benzenes) bearing poly(alkyleneoxy) electron-donor(s) and/or
hexylsulfonyl electron-acceptor(s). In addition, the influence of
substitution on various physical properties including the
absorption spectroscopic properties, the third-order nonlinear
optical properties and the thermal behaviour will be discussed.
For practical applications, the active chromophores or OPVs
are required to be developed in the form of either side-
chain or main-chain polymers in order to obtain better misci-
bility, a larger chromophore density and a higher thermal
stability. Towards this end, we also report the synthesis of the
acrylic monomer and polyacrylate bearing the corresponding
donor–acceptor disubstituted distyrylbenzene unit.
Results and Discussion
It has recently been shown that highly p-conjugated PPV
thin-films possess a large effective nonlinear refractive index
and a desirable two-photon merit factor for all-optical switch-
ing.10 This suggests that PPV-based materials may be potential
candidates for applications in all-optical signal processing. It
has also been shown that the third-order nonlinear optical
properties of PPV originate from the relatively short p-
conjugated chain segments of the polymer.11 Therefore, it is of
interest to understand and establish the structure–property
relationship of the well-defined oligo-phenylenevinylenes
(OPV) in order to further explore and optimize the PPV-based
materials for photonic applications. Unfortunately, there are
still no reliable guidelines for optimizing the second molecular
hyperpolarizability, c, of an organic molecule, in contrast to
the first molecular hyperpolarizability, b. In addition, the
In general, any solubilizing substituent grafted on the lateral
side of the main chain of an oligomer (including a vinylic
linkage) will greatly distort the co-planarity of the p-conjugated
system, leading to a decrease in conjugation and in desirable
physical properties. Therefore, in this study, the solubilizing
substituents will only be placed at the ends of the main chain
of an oligomer. Although several symmetrically disubstituted
distyrylbenzenes were previously synthesized for spectroscopic
studies we have found that their solubilities were often too
low to perform any reliable nonlinear optical measurement in
solution [e.g. the solubility of 1,4-bis(-4-bromostyryl)benzene
in chloroform is less than 0.1% w/w). To overcome this, the
poly(alkyleneoxy) and alkylsulfonyl moieties were incorporated
into the ends of the main chain to act as solubilizing as well
as electron-donating and electron-withdrawing substituents,
respectively.
The stereoselective Wadsworth–Emmons reaction was used
to construct the trans carbon–carbon double bonds. The
†Present address: Department of Chemistry, Hong Kong Baptist
University, Hong Kong.
J. Mater. Chem., 1998, 8(9), 2005–2009
2005

O
P
O
P
i
BrCH2
CH2Br + P(OC2H5)3
(C2H5O)2
C
C
(OC2H5)2
H2
H2
2
1
3
ii
iii
+
R
H
F
CHO
R
CHO
R′
CHO
9 R′ = C6H13SO2
6
4 R = C6H13
S
7 R = C6H13S
8 R = C4H9O(C2H4O)2
5 R = C4H9O(C2H4O)2
C4H9O(C2H4O)2
iv
3 + 8
(OC2H4)2OC4H9
10
C6H13O2S
iv
3 + 9
SO2C6H13
11
O
C4H9O(C2H4O)2
+
9
C
P
(OC2H5)2
H2
iv
12
C4H9O(C2H4O)2
SO2C6H13
13
Scheme 1 Reagents and conditions: i, 150 °C; ii, K CO , DMSO, 150 °C; iii, MCPBA, CH Cl , 0 °C; iv, NaH, DME, room temp.
2
3
2 2
general scheme for the synthesis of symmetrically and unsym-
metrically 4,4∞-disubstituted distyrylbenzenes is summarized in
Scheme 1. The bis-phosphonate 3 was prepared by the
Michaelis–Arbuzov reaction using a,a∞-dibromo-p-xylene 1 and
triethyl phosphite 2. The solubilizing hexylsulfanyl and 2-(2-
butoxyethoxy)ethoxy substituents, were introduced by aro-
matic nucleophilic substitution of 4-fluorobenzaldehyde 6
affording the corresponding aldehydes 7 and 8, respectively.
The Wadsworth–Emmons reaction of the bis-phosphonate 3
with 2 equiv. of aldehyde 8 yielded the corresponding symmetri-
cal distyrylbenzene 10. Surprisingly, the yellow product
obtained from the Wadsworth–Emmons reaction of 3 and 2
equiv. of 7 was not soluble enough to be characterized analyti-
cally by the conventional spectroscopic techniques. However,
the oxidation of this yellow solid with 3-chloroperoxybenzoic
acid (MCPBA) afforded the highly soluble distyrylbenzene 11.
Alternatively, the hexylsulfanyl functionality of 7 could be
converted into the hexylsulfonyl functionality by means of
MCPBA oxidation. Subsequent double Wadsworth–Emmons
reactions also gave the desired distyrylbenzene 11. To synthe-
size the donor–acceptor disubstituted distyrylbenzene 13, the
precursor mono-phosphonate 12 was first prepared from the
reaction of the aldehyde 8 and excess of the bis-phosphonate
3, followed by Wadsworth–Emmons reaction with aldehyde 9.
It was found that reversing the reaction sequence did not
afford the desired product, as the corresponding mono-
phosphonate could not be prepared directly from this method.
The synthetic route for the preparation of the methacrylate
monomer bearing the poly(alkyleneoxy) alkylsulfonyl 4,4∞-
disubstituted distyrylbenzene is outlined in Scheme 2. A similar
synthetic approach as used above was adopted to prepare the
functionalized poly(alkyleneoxy) alkylsulfonyl 4,4∞-disubsti-
tuted distyrylbenzene 18. The reaction of the chromophore 18
with methacrylic anhydride in the presence of dimethylamino-
pyridine (DMAP) as catalyst and triethylamine as base
afforded the methacrylate monomer 19. To demonstrate the
ability of this monomer to be polymerized, thermal radical
polymerization conditions were employed to co-polymerize
the methacrylate monomer 19 with MMA using the procedure
described by Robello.13 With an 8.3% w/w dye content in the
feed composition, the estimated weight average of copolymer
derived from gel permeation chromatography (GPC) is
35 000 g mol−1 with T =124 °C. More detailed characteriz-
reported elsewhere.
g
ation and the physical properties of the copolymer will be
The results of the electronic absorption measurements, the
third-order nonlinearities determined by Z-scan measurements
using 800 nm irradiation wavelength and the thermal proper-
ties are summarized in Table 1. As seen from the electronic
absorption spectra (Fig. 1), all the compounds show strong
and intense low-lying absorption bands which indicate a highly
p-conjugated system. Unlike the donor–acceptor 4,4∞-disubsti-
tuted distyrylbenzene 13, the low-lying absorption bands of
the symmetrically 4,4∞-disubstituted distyrylbenzenes 10 and
11 are apparently composed of several vibronic electronic
transitions.14 There are also significant bathochromic shifts of
the absorption maxima l
of the 4,4∞-disubstituted distyryl-
max
benzenes compared to that of the unsubstituted distyrylbenzene
(Dl=12–19 nm),12 in spite of the moderate donating and
withdrawing strength of the 2-(2-butoxyethoxy)ethoxy and
hexylsulfonyl functionalities, respectively. Such a red shift is
consistent with the fact that the donating and withdrawing
substituents at the para-positions of distyrylbenzene enhance
the p-electron delocalization along the entire unsaturated
system. On the other hand, the donor–acceptor 4,4∞-disubsti-
tuted distyrylbenzene 13 exhibits only a small bathochromic
2006
J. Mater. Chem., 1998, 8(9), 2005–2009

O
P
C10H21
S
i
C
10H21
S
CHO
+
3
C
(OC2H5)2
H2
14
15
ii
O
P
+
C10H21SO2
HO (C2H4O)2
CHO
C
(OC2H5)2
H2
17
16
i
HO (C2H4O)2
SO2C10H21
18
iii
O
O
(C2H4O)2
SO2C10H21
19
Scheme 2 Reagents and conditions: i, NaH, DME, room temp.; ii, MCPBA, CH Cl ; iii, DMAP, Et N, methacrylic anhydride, room temp.
2
2
3
shift of l
max
compared to those of the symmetrically 4,4∞-
disubstituted analogues (Dl=5–7 nm). This is presumably due
to the strong inductive nature of the hexylsulfonyl group.
To evaluate the third-order molecular nonlinearities, the
Z-scan technique15 was employed as it can determine the sign,
Table 1 Summary of the measured physical properties of 10, 11, and 13
l
/nm
transition
temperature/
°C
max
(e/10−4 −1
c
/
c
/
real
imag
Compound
cm−1)
10−36 esu
10−36 esu
the real part of the molecular nonlinearity c
real
to the refractive nonlinearity) and the imaginary part of the
molecular nonlinearity c (due to the multi-photon absorp-
tion). All the 4,4∞-disubstituted distyrylbenzenes exhibit positive
(which relates
10
11
13
368 (7.78)
370 (7.62)
375 (5.97)
200
250
420
54
95
200
46, 225
231, 259
216
imag
c
the 2-(2-butoxyethoxy)ethoxy and hexylsulfonyl functionali-
values. In spite of the very different electronic nature of
real
ties, both of the symmetrically 4,4∞-disubstituted distyrylbenz-
enes 10 and 11 show comparable c
values. On the other
real
hand, the donor–acceptor 4,4∞-disubstituted distyrylbenzene 13
exhibits an enhanced c compared to those of its symmetri-
cally disubstituted counterparts 10 and 11. This confirms the
real
advantage of using conjugated donor and acceptor substituents
to enhance c,16 in particular the poly(alkyleneoxy) alkylsulfonyl
pair which have been shown to provide an excellent trans-
parency–nonlinearity trade-off. In contrast to their c values,
bis(hexylsulfonylstyryl)benzene 11 shows
higher c
real
a
than that of bis[2-(2-butoxyethoxy)ethoxystyryl]-
substantially
imag
benzene 10. The c
value of the donor–acceptor 4,4∞-disubsti-
imag
tuted distyrylbenzene 13 is also relatively large, presumably
due to the relatively strong two-photon absorption at
irradiation wavelength.
With the incorporation of the solubilizing substituents, the
distyrylbenzene derivatives and the corresponding metha-
crylate monomer show enhanced solubility in various solvents;
in particular, the donor–acceptor 4,4∞-disubstituted distyryl-
benzene 13 has a solubility of more than 6% w/w in chloroform.
The solubilizing substituents also induce liquid crystalline
phases of the symmetrically 4,4∞-disubstituted distyrybenzenes
(10 and 11).
Experimental
All the new compounds were fully characterized with standard
spectroscopic techniques. All the physical measurements were
Fig. 1 Electronic absorption spectra of (+) 10, (#) 11 and (6) 13
measured in chloroform
J. Mater. Chem., 1998, 8(9), 2005–2009
2007

performed in CHCl . 1H NMR spectra were recorded using a
Varian Gemini-300 FT NMR spectrometer and are referenced
170 mg, 0.34 mmol) in anhydrous DME was slowly added 1.2
equiv. of NaH (15 mg, 0.42 mmol) at 0 °C. After stirring for
0.5 h at 0 °C, the reaction mixture was slowly warmed up to
room temp. After stirring for 2 h at room temp., the solution
was quenched with water. The crude product was either
collected by suction filtration or extracted twice with CH Cl ,
3
to the residual CHCl (7.24 ppm). Infrared spectra were
recorded using a Perkin-Elmer System 2000 FT-IR spec-
3
trometer. Electronic absorption (UV–VIS) spectra were
recorded using a Shimadzu UV-3101PC Spectrophotometer.
Thermal properties were determined by differential scanning
calorimetry (DSC) using a Shimadzu Thermal Analysis System
TA-50ASI with a heating rate of 10 °C min−1. The reported
temperatures were the peak temperature of the traces obtained
from the rerun. Molecular weight of the co-polymer was
estimated by gel permeation chromatography (GPC) using a
Spectra Physics HPLC instrument equipped with a Jordi
Mixed-Bed GPC column. THF was used as the eluent with
toluene as an internal standard. The polystyrene standards
were used for the calibration.
2
2
dried over anhydrous MgSO and evaporated to dryness. The
crude product was then purified by silica gel chromatography
using the gradient elution technique with CH Cl –ethyl acetate
4
2
2
as eluent [affording 110 g (54%) of 13]. For the double
Wadsworth–Emmons reactions, a 251 mixture of aldehyde (i.e.
9: 350 mg, 1.37 mmol) and phosphonate ester (i.e. 3: 260 mg,
0.69 mmol) was used [affording 170 mg (43%) of 11].
1,4-Bis{4-[2-(2-butoxyethoxy)ethoxy]styryl}benzene 10. 1H
NMR (300 MHz, CDCl ) d 7.44 (s, 4H), 7.42 (d, J 8.91 Hz,
4H), 7.05 (d, J 16.20 Hz, 2H), 6.94 (d, J 16.30 Hz, 2H), 6.89 (d,
3
Z-Scan measurements were performed with
a
system
consisting of a Coherent Mira Ar-pumped Ti-sapphire laser
generating a mode-locked train of approximately 100 fs 800 nm
pulses and a Ti-sapphire regenerative amplifier pumped by a
Q-switched pulsed YAG laser at 30 Hz. The open- and closed-
aperture Z-scans were recorded at two or three concentrations
for each compound, and the real and imaginary part of the
nonlinear phase shift was determined by numerical fitting. The
real and imaginary parts of the hyperpolarizability of the
solute were calculated by assuming a linear concentration
dependence of the solution susceptibility. The nonlinearities
and light intensities were calibrated using measurements of a
1 mm thick silica plate for which the nonlinear refractive index
J 8.79 Hz, 4H), 4.15 (t, J 4.88 Hz, 4H), 3.86 (t, J 4.88 Hz, 4H),
3.71 (m, 4H), 3.60 (m, 4H), 3.46 (t, J 6.72 Hz, 4H), 1.55 (m,
4H), 1.35 (m, 4H), 0.90 (t, J 7.28 Hz, 6H). MS (EI) m/z 602.3
(M+). HRMS (EI) C H O : calc. 602.3607 found, 602.3628.
38 50
6
n
(CH Cl )/cm−1 3029, 2934, 2875, 1605, 1516, 1457, 1250,
max
2 2
1176, 1111, 1065. Crystal–mesophase=46 °C, mesophase–
isotropic=225 °C. Found: C, 75.60; H, 8.59. C H O requires
C, 75.72; H, 8.34%.
38 50
6
1,4-Bis[4-(hexylsulfonyl)styryl]benzene 11. 1H NMR
(300 MHz, CDCl ) d 7.87 (d, J 8.46 Hz, 4H), 7.66 (d, J 8.52 Hz,
3
4H), 7.55 (s, 4H), 7.25 (d, J 16.32 Hz, 2H), 7.15 (d, J 16.26 Hz,
2H), 3.08 (t, J 8.1 Hz, 4H), 1.70 (m, 4H), 1.34 (m, 4H), 1.24
(m, 8H), 0.84 (t, J 6.84 Hz, 6H). MS (EI) m/z 578.2 (M+).
n =3×10−16 cm2 W−1 was assumed.
General procedure for the aromatic nucleophic substitution
2
HRMS (EI) C H O S : calc. 578.2525, found 578.2523.
(CH Cl )/cm−1 3018, 2930, 2859, 1592, 1511, 1466,
34 42 4 2
n
To an equimolar solution of 4-fluorobenzaldehyde 6 (2 ml,
18.6 mmol) and the corresponding solubilizing substituent (e.g.
4: 2.6 ml, 18.6 mmol) in DMSO was added 2 equiv. of Na CO
max
2 2
1310, 1142, 1089. Crystal–mesophase=231 °C, mesophase–
isotropic=259 °C. Found: C, 70.47; H, 7.17; S, 10.94.
C H O S requires C, 70.55; H, 7.31; S, 11.08%.
2
3
(i.e. 5.2 g, 37.3 mmol). The mixture was heated at 150 °C for
24 h under N . After cooling to room temp., the reaction
34 42 4 2
2
Diethyl 4-{4-[2-(2-butoxyethoxy)ethoxy]styryl}benzylphos-
phonate 12. 1H NMR (300 MHz, CDCl ) d 7.40 (d, J 8.79 Hz,
4H), 7.24 (dd, J 8.19 Hz, J 2.40 Hz, 2H), 7.01 (d, J 16.47 Hz,
mixture was poured into water and extracted twice with
CH Cl , dried over anhydrous MgSO and evaporated to
3
2
2
4
dryness. The crude product was then purified by silica gel
chromatography using the gradient elution technique with
CH Cl –ethyl acetate as eluent [affording 3.79 g (91%) of 7].
2H), 6.89 (d, J 16.41 Hz, 1H), 6.88 (d, J 8.70 Hz, 2H), 4.12 (t,
J 5.22 Hz, 2H), 3.99 (m, 4H), 3.84 (t, J 4.98 Hz, 2H), 3.70 (m,
2H), 3.58 (m, 4H), 3.58 (m, 2H), 3.44 (t, J 6.72 Hz, 2H), 3.12
(d, J 21.69 Hz, 1H), 1.55 (m, 2H), 1.32 (m, 2H), 1.22 (t, J
6.99 Hz, 6H), 0.89 (t, J 7.41 Hz, 3H).
2
2
4-Hexylsulfanylbenzaldehyde 7. 1H NMR (300 MHz, CDCl )
d 9.89 (s, 1H), 7.73 (d, J 8.55 Hz, 2H), 7.31 (d, J 8.31 Hz, 2H),
3
2.97 (t, J 7.37 Hz, 2H), 1.68 (m, 2H), 1.29 (m, 2H), 1.28 (m,
4H), 0.86 (t, J 7.11 Hz, 3H).
1-{4-[2-(2-Butoxyethoxy)ethoxy]styryl}-4-(4-hexylsulfonyls-
tyryl)benzene 13. 1H NMR (300 MHz, CDCl ) d 7.85 (d, J
8.49 Hz, 2H), 7.64 (d, J 8.52 Hz, 2H), 7.49 (s, 4H), 7.43 (d, J
3
4-[2-(2-Butoxyethoxy)ethoxy]benzaldehyde 8. 1H NMR
(300 MHz, CDCl ) d 9.85 (s, 1H), 7.79 (d, J 8.64 Hz, 2H), 6.99
8.79 Hz, 2H), 7.23 (d, J 16.38 Hz, 1H), 7.10 (d, J 16.41 Hz,
1H), 7.09 (d, J 16.41 Hz, 1H), 6.95 (d, J 16.26 Hz, 1H), 6.90 (d,
J 8.79 Hz, 2H), 4.14 (t, J 4.92 Hz, 2H), 3.86 (t, J 4.94 Hz, 2H),
3.71 (m, 2H), 3.59 (m, 2H), 3.46 (t, J 6.72 Hz, 2H), 3.07 (t, J
8.10 Hz, 2H), 1.70 (m, 2H), 1.56 (m, 2H), 1.33 (m, 4H), 1.24
(m, 4H), 0.90 (t, J 7.35 Hz, 3H), 0.84 (t, J 6.87 Hz, 3H). MS
(EI) m/z 590.2 (M+). HRMS (EI) C H O S: calc. 590.3066,
3
(d, J 8.82 Hz, 2H), 4.19 (t, J 4.79 Hz, 2H), 3.86 (t, J 4.79 Hz,
2H), 3.70 (m, 2H), 3.58 (m, 2H), 3.43 (t, J 6.72 Hz, 2H), 1.53
(m, 2H), 1.32 (m, 2H), 0.87 (t, J 7.80 Hz, 3H).
4-Hexylsulfonylbenzaldehyde, 9
36 46
5
To a stirred solution of 7 (400 mg, 1.8 mmol) in CH Cl at
found 590.3077. n (CH Cl )/cm−1 3029, 2960, 2933, 1591,
2
2
max
2 2
0 °C was slowly added MCPBA (650 mg, 3.6 mmol). After
stirring for 1 h, the white suspension was filtered off and the
filtrate was washed with Na CO solution, dried over anhy-
1514, 1459, 1307, 1250, 1176, 1143, 1111, 1089. Mp=216 °C.
Found: C, 73.20; H, 8.12; S, 5.16. C H O S requires C, 73.19;
H, 7.85; S, 5.43%.
36 46
5
2
3
drous MgSO and evaporated to dryness. The crude product
was then purified by silica gel chromatography using the
gradient elution technique with CH Cl –ethyl acetate as eluent
4
Diethyl 4-(4-decylsulfanylstyryl)benzylphosphonate 15. 1H
NMR (300 MHz, CDCl ) d 7.43 (d, J 8.79 Hz, 2H), 7.40 (d, J
8.61 Hz, 2H), 7.27 (d, J 8.37 Hz, 2H), 7.02 (s, 2H), 4.00 (m,
2
2
3
affording 350 g of 9 in 76% yield. 1H NMR (300 MHz, CDCl )
d 10.12 (s, 1H), 8.07 (s, 4H), 3.10 (t, J 8.09 Hz, 2H), 1.69 (m,
2H), 1.34 (m, 2H), 1.23 (m, 4H), 0.83 (t, J 6.78 Hz, 3H).
3
4H), 3.14 (d, J 21.72 Hz, 2H), 2.91 (t, J 7.38 Hz, 2H), 1.62 (m,
2H), 1.40 (m, 2H), 1.23 (m, 20H), 0.86 (d, J 6.74 Hz, 3H). MS
(EI) m/z 502.1 (M+).
General procedure for the Wadsworth–Emmons reaction
To an equimolar solution of an aldehyde (i.e. 9: 89 mg,
0.34 mmol) and the corresponding phosphonate ester (i.e. 12:
Diethyl 4-(4-decylsulfonylstyryl)benzylphosphonate 16. 1H
NMR (300 MHz, CDCl ) d 7.85 (d, J 8.46 Hz, 2H), 7.63 (d, J
3
2008
J. Mater. Chem., 1998, 8(9), 2005–2009

8.55 Hz, 2H), 7.47 (d, J 7.92 Hz, 2H), 7.30 (dd, J 8.31 Hz, J
2.46 Hz, 2H), 7.21 (d, J 16.47 Hz, 1H), 7.08 (d, J 16.26 Hz,
1H), 4.01 (m, 4H), 3.14 (d, J 21.96 Hz, 2H), 3.06 (t, J
8.01 Hz, 2H), 1.69 (m, 2H), 1.23 (m, 22H), 0.86 (d, J 6.75 Hz,
3H). MS (EI) m/z 534.1 (M+).
developed. The thermal free-radical copolymerization of distyr-
ylbenzene-derived methacrylate monomer with MMA has been
shown to be achievable. All distyrylbenzene derivatives show
excellent solubility, processibility and thermal stability. In
addition to enhanced third-order nonlinearity, the 2-(2-butoxy-
ethoxy)ethoxyhexylsulfonyl 4,4∞-disubstituted distyrylbenzene
exhibits an excellent transparency–nonlinearity trade-off
compared to those of the symmetrically 4,4∞-disubstituted
distyrylbenzenes.
1-{4-[2-(2-Hydroxyethoxy)ethoxy]styryl}-4-(4-decyl-
sulfonylstyryl)benzene 18. 1H NMR (300 MHz, CDCl ) d 7.85
(d, J 8.46 Hz, 2H), 7.65 (d, J 8.46 Hz, 2H), 7.50 (s, 4H), 7.45
3
(d, J 8.64 Hz, 2H), 7.23 (d, J 16.24 Hz, 1H), 7.11 (d, J 16.20 Hz,
1H), 7.09 (d, J 16.26 Hz, 1H), 6.96 (d, J 16.41 Hz, 1H), 6.91 (d,
J 8.82 Hz, 2H), 4.15 (s, 2H), 3.87 (s, 2H), 3.76 (m, 2H), 3.67
(m, 2H), 3.07 (t, J 7.80 Hz, 2H), 1.70 (m, 2H), 1.21 (m, 16H),
0.85 (t, J 6.69 Hz, 3H). MS (FAB) m/z 590.1 (M+).
We gratefully acknowledge the Australian Photonics
Cooperative Research Centre for financial support and
N. T. Lucas for the GPC analysis. M.G.H. is an ARC
Australian Research Fellow.
Synthesis of 19
References
To a stirred solution of 18 (240 mg, 0.41 mmol), freshly distilled
methacrylic anhydride (75 mg, 0.49 mmol) and 3-tert-butyl-4-
hydroxy-5-methylphenyl sulfide (15 mg, 0.04 mmol) in anhy-
drous CH Cl at room temp. was slowly added a solution of
1
2
3
B. Luther-Davies and M. Samoc, Curr. Opin. Solid State Phys.,
1997, 2, 213.
J. Burroughs, D. D.Bradley, A. R. Brown, R. N. Marks, K. Mackey,
R. H. Friend, P. L. Burns and A. B. Holmes, Nature, 1990, 347, 539.
M. Hirooka, I. Murase, T. Ohnishi and T. Noguchi, in Frontiers of
Macromolecular Science, ed. T. Saegusa, Blackwell Scientific
Publications, Oxford, UK, 1989, p. 425.
F. Hide, M. A. Diaz-Garcia, B. J. Schwartz and A. I. Heeger, Acc.
Chem. Res., 1997, 30, 430.
D. R. Gagnon, J. D. Capistran, F. E. Karasz and R. W. Lenz,
Polym. Bull., 1984, 12, 293.
S. Antoun, F. E. Karasz and R. W. Lenz, J. Polym. Sci., Part A,
1988, 26, 1809.
Z. Bao, Y. Chen, R. Cai and L. Yu, Macromolecules, 1993, 26, 5281.
R. M. Gurge, A. Sarker, P. M. Lahti, B. Hu and F. E. Karasz,
Macromolecules, 1996, 29, 4287.
2
2
DMAP (6 mg, 0.04 mmol) and Et N (49 mg, 0.49 mmol) in
CH Cl . The reaction was monitored by TLC. After complete
3
2
2
disappearance of 18 via TLC, the reaction mixture was
quenched with water and extracted twice with CH Cl , dried
4
5
6
2
2
over anhydrous MgSO and evaporated to dryness. The crude
product was purified by silica gel chromatography using the
gradient elution technique with CH Cl –ethyl acetate as eluent,
4
2
2
affording 125 mg (47%). 1H NMR (300 MHz, CDCl ) d 7.85
(d, J 8.46 Hz, 2H), 7.65 (d, J 8.55 Hz, 2H), 7.50 (s, 4H), 7.44
3
7
8
(d, J 8.79 Hz, 2H), 7.23 (d, J 16.38, 1H), 7.11 (d, J 16.47, 1H),
7.09 (d, J 16.41, 1H), 6.96 (d, J 16.35 Hz, 1H), 6.90 (d, J
8.82 Hz, 2H), 6.12 (m, 1H), 5.56 (m, 1H), 4.33 (t, J 4.80 Hz,
2H), 4.14 (t, J 4.59 Hz, 2H), 3.87 (t, J 4.77 Hz, 2H), 3.82 (t, J
4.86 Hz, 2H), 3.07 (t, J 7.95 Hz, 2H), 1.93 (m, 3H), 1.70 (m,
2H), 1.21 (m, 16H), 0.85 (t, J 6.42 Hz, 3H). MS (EI) m/z 658.3
(M+). HRMS (EI) C H O S: calc. 658.3328, found 658.3336.
9
T. Maddux, W. Li and L. Yu, J. Am. Chem. Soc., 1997, 119, 844.
10 A. Samoc, M. Samoc, M. Woodruff and B. Luther-Davies, Opt.
L ett., 1995, 20, 1241.
11 C. Bubeck, in Organic T hin Films for Waveguiding Nonlinear
Optics, ed. F. Kajzar and J. D. Swalen, Gordon and Breach
Publishers, Amsterdam, The Netherlands, 1996, p. 137.
12 S. Nakatsuji, K. Matsuda, Y. Uesugi, K. Nakashima, S. Akiyama,
G. Katzer and W. Fabian, J. Chem. Soc., Perkin T rans. 2, 1991, 861.
13 D. R. Robello, J. Polym. Sci., Part A: Polym. Chem., 1990, 28, 1.
14 N. N. Barashkov, D. J. Guerrero, H. J. Olivos and J. P. Ferrais,
Synth. Met., 1995, 75, 153.
60 50
6
n
(CH Cl )/cm−1 3029, 2929, 2857, 1718, 1591, 1514, 1299,
max
2 2
1250, 1176, 1141, 1089. Mp=213 °C; decomp. temp.=290 °C.
Conclusions
15 M. Samoc, A. Samoc, B. Luther-Davies, Z. Bao, L. Yu, B. Hsieh
and U. Scherf, J. Opt. Soc. Am. B, 1998, 15, 817.
A novel series of poly(alkyleneoxy) and/or alkylsulfonyl 4,4∞-
disubstituted distyrylbenzenes has been synthesized.
Furthermore, the distyrylbenzene-derived methacrylate mon-
omer has been synthesized by adopting the synthetic route
16 C. Bosshard, R. Spreiter, P. Gunter, R. R. Tykwinski, M. Schreiber
¨
and F. Diederich, Adv. Mater., 1996, 8, 231.
Paper 8/03229G; Received 29th April, 1998
J. Mater. Chem., 1998, 8(9), 2005–2009
2009