2
152 Spiliopoulos and Mikroyannidis
Macromolecules, Vol. 35, No. 6, 2002
solution of KOH (1.66 g, 41.16 mmol) in water over a period
of 30 min at room temperature. A white precipitate was
formed, and stirring was continued overnight. The precipitate
was filtered, washed with water and then with ethanol, and
dried to afford 5 as a white solid (6.20 g, 78%). It was
recrystallized from ethanol. Mp: 63-65 °C.
-
1
IR (KBr, cm ): 2918, 2842 (C-H stretching of CH
CdO); 1600, 1576, 1512 (aromatic and double bond); 1264,
212 (ether bond).
3
); 1658
(
1
1
H NMR (CDCl
double bond); 3.87 (s, 3H, OCH
-(4-Met h oxyp h en yl)-2-(4-b r om op h en yl)-6-p h en ylp y-
r yliu m tetr a flu or obor a te (6). Boron trifluoride etherate
2.64 mL, 21.01 mmol) was added to a solution of 5 (2.00 g,
.40 mmol) and acetophenone (0.84 g, 4.20 mmol) in 1,2-
dichloroethane (15 mL). The solution was heated at 80 °C for
h under N . It was subsequently concentrated under reduced
3
), ppm: 7.98-6.94 (m, 9H aromatic and 2H
3
).
4
(
8
3
2
F igu r e 1. 1H NMR spectrum of P Vb in CDCl
solution.
3
pressure, and the residue was triturated with dioxane. The
resulting solid was filtered, washed with dioxane, and dried,
yielding 6 as a yellow solid (1.42 g, 67%). It was recrystallized
from acetic acid. Mp: 181-182 °C.
monomers. This method has been developed in our
laboratory and has been used for the preparation of
-
1
24,25
IR (KBr, cm ): 2919, 2854 (C-H stretching of CH
3
); 1616,
other photonic polymers.
The key step is the syn-
1
588, 1510, 1490 (aromatic and pyrylium structure); 1246
thesis of the pyrylium salt and its reaction with sub-
stituted acetic acid anhydride. More particularly, the
reaction of 4-methoxybenzaldehyde with 4-bromo-
acetophenone in the presence of BF3‚Et2O yielded
pyrylium salt 1. The latter was condensated with
-
(
ether bond); 1074 (BF
4
).
), ppm: 8.32 (s, 2H, aromatic meta to O );
.90-7.40 (m, 4H, aromatic ortho and meta to Br); 7.21-6.88
).
-Br om o-2′,5′-d i(4-m et h oxyp h en yl)-m -t er p h en yl (7).
Compound 7 was prepared in 62% yield by reacting 6 with
-methoxyphenylacetic acid sodium salt according to the
1
+
H NMR (DMSO-d
6
7
(m, 9H, other aromatic); 4.38 (s, 3H, OCH
3
4
4
-methoxyphenylacetic acid anhydride, generated in
situ from 4-methoxyphenylacetic acid sodium salt and
acetic anhydride, to afford compound 2. The methoxy
groups of 2 were hydrolyzed by means of hydrobromic
acid to the corresponding bisphenol 3. Dialkoxy-substi-
tuted dibromides 4 were synthesized by the Williamson
reaction of 3 with bromoalkanes.
Compounds 4 were used as starting materials for the
preparation of the polymers (Scheme 2). The Heck
reaction of 4 with p-divinylbenzene yielded polymers
P Va and P Vb. The polymers were obtained in high
yields (95-97%) and the molecular weights (Mn) ranged
from 3100 to 3400. It is known that in the most cases
the molecular weights of the polymers obtained via Heck
coupling are relatively low.
4
procedure described for 2. It was recrystallized from CH
Mp: 170-172 °C.
3
CN.
-
1
IR (KBr, cm ): 3030 (C-H stretching of aromatic); 2930,
2
832 (C-H stretching of CH
3
); 1608, 1516 (aromatic); 1242
(ether bond).
1
H NMR (CDCl
3
), ppm: 8.02 (s, 2H, aromatic at positions
4
2
8
′,6′ of m-terphenyl); 7.85-7.42 (m, 9H, aromatic at positions
, 3, 5, 6, 2′′′, 3′′′, 4′′′, 5′′′,6′′′ of m-terphenyl); 7.25-7.08 (m,
H, aromatic of side phenyls); 4.41, 4.34 (d, 6H, OCH ).
-Br om o-2′,5′-d i(4-h yd r oxyp h en yl)-m -t er p h en yl (8).
3
4
Compound 8 was prepared according to the procedure de-
scribed for 3 as a white solid in 86% yield. It was recrystallized
from o-dichlorobenzene. Mp: 165-167 °C.
-
1
IR (KBr, cm ): 3334 (O-H stretching); 1610, 1593, 1518
(
aromatic); 1256 (O-H deformation).
Scheme 3 depicts the synthetic route applied for the
preparation of model compound 10. The method for the
synthesis of monobromo compound 9 was similar to that
used for monomers 4. The only difference was the two-
step synthesis of pyrylium salt 6. Specifically, the latter
was prepared by the condensation of 4-methoxybanzal-
dehyde with acetophenone to yield 5, which subse-
quently afforded 6 by reacting with 4-bromoacetophe-
none in the presence of BF ‚Et O. Compound 10 was
1
H NMR (DMSO-d ), ppm: 9.58, 9.31 (d, 2H, OH); 7.71-
6
7
.25 (m, 11H, aromatic of m-terphenyl); 6.91-6.53 (m, 8H,
aromatic of side phenyls).
-Br om o-2′,5′-d i[4-(2-e t h ylh e xyloxy)p h e n yl]-m -t e r -
4
p h en yl (9). Compound 9 was synthesized in 77% yield
according to the method described for 4a . It was recrystallized
from CCl . Mp: 122-124 °C.
4
IR (KBr, cm-1): 2924, 2856 (C-H stretching of the aliphatic
segments); 1608, 1516, 1488 (aromatic); 1454 (C-C stretching
3
2
of the aliphatic segments); 1242 (ether bond).
prepared by the Heck reaction of p-divinylbenzene with
a double molar amount of 9.
1
H NMR (CDCl ), ppm: 7.48-6.96 (m, 11H, aromatic of
3
m-terphenyl); 6.62-6.51 (d, 8H, aromatic of side phenyls); 3.95,
.84 (d, 4H, OCH ); 1.75-0.80 (m, 30H, other aliphatic).
,4-Bis{4-[2,5-d i(4-(2-eth ylh exyloxy)p h en yl)-3-p h en yl]-
Ch a r a ct er iza t ion of P olym er s. The structural
characterization of polymers was accomplished by el-
7
2
1
1
13
emental analysis and FT-IR, H NMR, and C NMR
p h en ylstyr yl}ben zen e (10). Model compound 10 was pre-
pared as a yellowish solid in 90% yield by reacting p-divinyl-
benzene with double molar amount of 9 according to the
method described for polymer P Va . It was recrystallized from
ethyl acetate. Mp: 165-167 °C.
1
spectroscopy as well as X-ray. Figure 1 shows the H
NMR spectra of polymer P Vb and the assignments of
peaks. The spectrum was in agreement with the pro-
posed structure. It showed multiplets at the regions of
3.94-3.77 and 1.74-0.80 ppm assigned to the aliphatic
protons. Aromatic and olefinic protons were overlapped
and appeared in the region of 7.55-6.49 ppm. The
olefinic protons resonated at 7.00 ppm, thus supporting
the formation of a trans olefinic bond. This observation
is consisted to the FT-IR spectrum of polymer, which
-
1
IR (KBr, cm ): 3026 (C-H stretching of aromatic); 2956,
926, 2870 (C-H stretching of the aliphatic segments); 1608,
516 (aromatic); 1454, 1434 (C-C stretching of the aliphatic
2
1
segments); 1242 (ether bond); 964 (HCdCH trans).
1
H NMR (CDCl ), ppm: 7.61-7.48 (m, 38H aromatic and 4H
3
olefinic); 3.95-3.76 (d, 8H, OCH ); 1.78-0.76 (m, 60H, other
2
aliphatic).
-
1
presented an absorption at 964 cm characteristic of
Resu lts a n d Discu ssion
1
,2-disubstituted trans-vinylene unit.
P r ep a r a tion of Mon om er s a n d P olym er s. Scheme
outlines the method applied for the preparation of
The introduction of side aliphatic groups along the
polymers backbone aimed to produce soluble polymers.
1