From terphenyl-dendronized macromonomers to aromatic-aliphatic polyethers bearing two pendant dendrons per repeating unit

Article abstract of DOI:10.1021/ma020255s

Novel side chain dendritic aromatic-aliphatic polyethers are synthesized from aromatic terphenyl diols, disubstituted with Frechet-type dendrons of the first and second generation and aliphatic dibromides of various lengths. High-molecular-weight soluble

Full text of DOI:10.1021/ma020255s

5808
Macromolecules 2002, 35, 5808-5815
From Terphenyl-Dendronized Macromonomers to Aromatic-Aliphatic
Polyethers Bearing Two Pendant Dendrons per Repeating Unit
A. K. An d r eop ou lou a n d J . K. Ka llitsis*
Department of Chemistry, University of Patras, GR-265 00 Patras, Greece, and Foundation for
Research and Technology-Hellas, Institute of Chemical Engineering and High-Temperature Chemical
Processes, P.O. Box 1414, GR-265 00 Patras, Greece
Received February 19, 2002; Revised Manuscript Received April 11, 2002
ABSTRACT: Novel side chain dendritic aromatic-aliphatic polyethers are synthesized from aromatic
terphenyl diols, disubstituted with Fre´chet-type dendrons of the first and second generation and aliphatic
dibromides of various lengths. High-molecular-weight soluble polymers were obtained in all cases. The
bulk properties of the polymers were examined by means of thermal analyses (DSC), dynamic mechanical
analyses (DMA), and X-ray diffractometry. Separation between the main chain and the dendritic side
chains was evident due to the existence of two well-resolved glass transition temperatures, observed by
both DSC and DMA measurements.
In tr od u ction
sequences and two Fre´chet-type poly(benzyl ether)
dendritic moieties13a on every repeating unit. The
general concept of our approach toward side chain
dendritic polymers is to reduce the steric effect due to
the space demanding dendrons. This was accomplished
with the use of monomers that carry the polymerizable
functionalities in less crowded sites that, moreover, do
not undergo cleavage under the polymerization condi-
tions. The introduction of the rigid terphenyl moieties
along the main chain in combination with the aliphatic
spacers, however, should allow less hindered conforma-
tions to be adopted, facilitating the completion of
polymerization. Moreover, aliphatic segments with a
variety in length were used, and together with the
increase in dendrons’ generation, their effect on the
thermal and mechanical properties of these new den-
dronized polymers was tested. All following monomers,
macromonomers, and dendronized polyethers were fully
Some of the most interesting macromolecular struc-
tures have appeared during the past years due to the
unique combination of traditional polymers with the
well-defined, monodisperse dendritic molecules.1 Such
dendronized or side chain dendritic polymers, bearing
pendant dendritic wedges on every single repeating
unit,2 have mainly been constructed through grafting
of the dendritic side groups on preformed linear poly-
meric chains,3 divergently developing the dendritic
fragments onto suitable side groups of the polymeric
backbones4 or polymerizing monomer units bearing the
desired dendrons prior to polymerization.2a The latter
case accepted as the “macromonomer” approach has
preferably been adopted for a variety of polymerization
techniques,5-10 leading to the formation of perfectly
substituted polymeric materials carrying dendrons onto
each repeating unit, thus allowing the visualization of
single macromolecular chains11,4b as well as understand-
ing the principles of stiffening classical polymers through
the attachment of these bulky three-dimensional sub-
stituents.12 Consequently, the final size, shape, rigidity,
and conformation of these macromolecular systems
should be directly controlled with the size or chemical
structure of the pendant dendritic moieties. The best
results have so far appeared in the literature either
when a spacer has been introduced between the side
dendrons and the polymerizable group, when self-
organization of the dendritic monomers occurs, or when
long reaction times have been adopted.2 On the other
hand, only a limited number of studies have, until now,
dealt with the properties of these new polymeric fea-
tures.10 Since high-molecular-weight polymers are al-
ways desirable, especially if solid-state properties of
such unique macromolecules are to be examined, easily
performed polymerization reactions should be employed
with monomers that facilitate chain growth, without
enhancing the overall rigidity, shape, and conformation
of the final polymeric chains.
1
characterized through GPC, H NMR, and 13C NMR,
and their thermal and mechanical properties were
investigated using DSC and DMA measurements.
Resu lts a n d Discu ssion
Mon om er a n d P olym er Syn th eses. The synthetic
procedure to macromonomers 8a and 8b, carrying first-
and second-generation Fre´chet-type dendrons, can be
viewed in Schemes 1 and 2. The choice of the particular
dendritic fragments relies on their well-established
syntheses and the fact that their properties have been
investigated probably more than any other homologous,
and moreover they have been used preferably in most
dendronized macromolecular systems allowing for safe
correlations. The preparation of the doubly substituted
aromatic dibromides 4a and 4b, and of the dendronized
macromonomers themselves, can be performed in gram
scale quantities, in an analogous procedure as in the
convergent method for dendrimers.13b Thus, polymeri-
zation can provide dendronized polymers in significant
quantities.
The need for a compound that could be employed in
Suzuki coupling14 with the dibromides 4a and 4b
producing the desired macromonomers was fulfilled by
the tetrahydropyranyl ether of p-bromophenol. In par-
ticular, the tetrahydropyranyl group remained intact
Herein we wish to report a synthetic pathway to
dendronized polyethers consisting of aromatic-aliphatic
* To whom correspondence should be addressed.
10.1021/ma020255s CCC: $22.00 © 2002 American Chemical Society
Published on Web 06/14/2002

Macromolecules, Vol. 35, No. 15, 2002
Macromonomers and Polyethers 5809
Sch em e 1a
a
(a) K2CO3, acetone, reflux for 18 h, 97 and 80%.
Sch em e 2a
quired applications, among other silyl ones, such as
triiopropylsilyl chloride and tert-butyldiphenylsilyl chlo-
ride that produced aromatic boronic acids difficult to
crystallize. On the other hand, selective cleavage of the
protective groups, with the use of PTSA (p-toluene-
sulfonic acid), in the presence of the side dendrons was
quantitative, as evident by the absence of their char-
acteristic peaks in the 1H NMR of the terphenyldiol
macromonomer 8a (Figure 1).
Polymerizations of dendronized macromonomers 8a
and 8b with R,ω-aliphatic dibromides were conducted
under phase transfer conditions in a mixture of o-DCB/
NaOH (10 N) containing TBAH (tert-butylammonium
hydrogen sulfate) as the phase transfer catalyst (Scheme
3).16 Polymerization conditions were only optimized for
the polymerization time of the second-generation den-
dron-carrying polymers. Moreover, effort was devoted
in accomplishing the correct stoichiometries due to great
differences between the monomers’ molecular weights.
High-molecular-weight polymers were obtained in most
cases (Tables 1 and 2) for both series PETH-G1 and
PETH-G2, respectively. The molecular weights were
initially determined by GPC using polystyrene stan-
dards, which is known to underestimate the molecular
weight of dendronized polymers.12 Thus, further mea-
surements for those polyethers carrying second-genera-
tion dendrons, PETH-G2, involved molecular weight
determination through GPC equipped with a light
scattering detector, which indeed measured higher
molecular weights for all polymeric samples, compared
to the GPC-UV detector system, as can be seen
throughout the second column of Table 2. For PETH-
a
(a) DHP, CH2Cl2, CSA, rt for 24 h. (b) n-BuLi, THF, -40
°C for 3 h, B(OMe)3, rt for 18 h, H2O, 88%. (c) 3 mol %
Pd(PPh3)4, Na2CO3 2 M, toluene, reflux for 18 h, 92%. (d) 4
mol % PdCl2(dppf), NaOH 3 M, THF, reflux 48 h, 85%. (e)
PTSA, DMA, MeOH, 80 °C, 42 h, 99%. (f) PTSA, THF, MeOH,
50 °C, 3 days, 80%.
both in the preparation of the corresponding boronic
ester (6) and during the Suzuki coupling even when
prolonged heating was required, as can be seen in
Figure 1, where in the inset 1H NMR of the THP-
protected terphenyldiol-carrying dendrons of the second
generation (7b), the characteristic peaks of the tetra-
hydropyranyl protective groups are clearly viewed at
1.5-2, 3.55, 3.85, and 5.35 ppm. This protective group
(3,4-dihydro-2H-pyran)15 gave best results, for the re-

5810 Andreopoulou and Kallitsis
Macromolecules, Vol. 35, No. 15, 2002
F igu r e 1. 1H NMR spectra of the THP-protected macromonomer 7b (inset) and of the dihydroxy-functionalized macromonomer
8b.
Sch em e 3a
Ta ble 1. GP C Da ta a n d Viscosim etr ic Ch a r a cter iza tion of
P ETH-G1 Sa m p les
time
(h)
[n]b
(dL/g)
a
a
a
Mn
50 000 227 000
30 500 60 200
34 500 167 200
Mw
Mn/Mw
PETH-G1-x)12
PETH-G1-x)11
16
12
16
12
192
16
4.5
2
1.2
0.7
4.7
2.1
2.4
3.8
2.6
27 000
28 900
25 000
13 300
55 000
69 500
96 000
34 600
PETH-G1-x)10
PETH-G1-x)9
PETH-G1-x)8
PETH-G1-x)7
0.61
0.35
0.4
16
16
16
16
15 600
13 700
37 160
29 370
2.4
2.2
a
Determined by GPC with a UV detector, CHCl3 as eluent, and
a
b
(a) o-DCB, NaOH 10 N, TBAH, 100 °C, 18 h. (b) Like (a),
polystyrene standards. In 1,1,2,2-tetrachloroethane at 30 °C.
7-12 days.
were initially dissolved in TCE and afterward diluted
with CHCl3, which was used as eluent. However, PETH-
G1-x)8 formed a stable gel under these conditions. On
the other hand, all polyethers PETH-G2 showed in-
creased solubilities in common chlorinated solvents like
chloroform.
G1 polymers intrinsic viscosity measurements also
revealed high values, especially for those polyethers
having high molecular weights (Table 1). Polyethers
PETH-G1 were completely soluble, at room temperature,
in chlorinated solvents like 1,1,2,2-tetrachloroethane
(TCE) while their solubility increased with the length
of the aliphatic segment along the main polymeric chain.
For the GPC characterization of PETH-G1, the samples
Dendronized polyethers from both series, even those
appendant with second-generation dendrons, were fully
1
characterized by H NMR, as can be viewed in Figure

Macromolecules, Vol. 35, No. 15, 2002
Macromonomers and Polyethers 5811
Ta ble 2. GP C Da ta for P ETH-G2 Sa m p les
a
b
b
b
time (h)
Mw
Mn
Mw
Mn/Mw
PETH-G2-x)12
16
16
96
24 300 13 600
47 850 16 600
119 300 18 100
18 950
25 500
74 300
1.8
1.6
4
PETH-G2-x)11
PETH-G2-x)10
168
60
240
60
240
192
288
281 000 48 600 135 070
2.8
2.7
2.3
2.7
2.5
2.7
3.5
23 700
64 430 19 650
26 900
64 500
43 650
72 800
PETH-G2-x)9
283 900 53 600 132 000
195 000 47 300 127 900
PETH-G2-x)8
PETH-G2-x)7
155 500 15 100
52 600
a
Determined by GPC with a LS detector and CHCl3 as eluent.
Determined by GPC with a UV detector, CHCl3 as eluent, and
b
polystyrene standards.
F igu r e 3. DSC thermograms for PETH-G1 samples: second
heating runs (a) and after annealing at room temperature for
4 months (b).
The polyethers’ thermal properties are presented in
Figures 3 and 4. Polyethers pendant with dendrons of
the first generation, PETH-G1, revealed complex DSC
thermograms with multiple transitions during the
second heating runs (Figure 3a). In particular, those
polymers having shorter spacers along the main chain
revealed multiple endotherms in the temperature region
from 100 to 170 °C, while only one endotherm at about
120 °C is present in the DSC traces of polyethers with
longer spacers (x ) 11, 12). Preliminary X-ray examina-
tion of the polyethers carrying first-generation dendrons
supports the presence of ordered structures. Thus, the
diffraction pattern of a film of PETH-G1-x ) 8 displays
at ambient temperature reflections at 2θ: 9.62, 12.915,
19.45, 22.52, and 26° corresponding to d ) 9.183, 6.848,
4.558, 3.943, and 3.423 Å, respectively, as shown in
Figure 5.
The glass transition temperatures of the Fre´chet-type
poly(benzyl ether) dendrons have been reported in the
temperature region from 30 to 50 °C.17a In our case, on
the other hand, there was some evidence of more than
one Tg, in the same region, during the second heating
runs. Thus, aging of the samples at room temperature
was employed in order to facilitate development of the
F igu r e 2. 1H NMR spectra of PETH-G2-x)12.
2, with complete assignment of all peaks, proving the
1
proposed structures. In the H NMR spectrum of both
polyethers’ groups, PETH-G1 and PETH-G2, respec-
tively, no end groups throughout the polymeric chains
were noticeable, since the aromatic protons neighboring
to the hydroxyl functionalities are easily distinguished
at 6.81 ppm moving up to 6.92 ppm for PETH-G1 (from
6.85 to 6.91 ppm for PETH-G2). Thus, the polymers’
molecular weights could not be calculated using end
group analyses, indicating at the same time their high
molecular weights and complete monomer consumption.
Th er m a l a n d Mech a n ica l P r op er ties. Polyethers
PETH-G1 and PETH-G2 were investigated for their
thermal and mechanical properties through differential
scanning calorimetry (DSC) and dynamic mechanical
analyses (DMA) measurements.

5812 Andreopoulou and Kallitsis
Macromolecules, Vol. 35, No. 15, 2002
F igu r e 4. DSC thermograms of the first heating runs for
PETH-G2 samples with x ) 12, 11, 10, and 9.
F igu r e 5. X-ray diffraction pattern for PETH-G1-x)8 in film
form.
enthalpy relaxations. This method has been employed
for the differentiation of the glass transition tempera-
tures in polymer blends in those cases where the Tg’s
of the two polymeric components are very close to each
other and overlapped.18 For that purpose the DSC
samples remained at room temperature for a period of
4 months, and their thermograms recorded afterward
are presented in Figure 3b, where clearly separated
enthalpy relaxation peaks can be seen for all polymeric
samples. From the above, it is also reasonable to assume
that the first transition at 35 °C is due to the dendron
substituents, since it seems to be independent of the
flexible spacer length and closer to the literature values.
On the other hand, the second one at about 50 °C shows
an “odd-even” effect, in agreement with our previous
findings for the same type of rigid-flexible alternating
polymers.19 This assignment of the two Tg’s is also
supported by the fact that the respective macromonomer
pendant with first-generation dendrons also exhibits a
glass transition at 35 °C.
F igu r e 6. DMA measurements for PETH-G1 (a) and PETH-
G2 (b) samples.
Although the influence of parameters like the molec-
ular weight, the chemical structure, and the type of
chain ends on Tg has been studied in the case of
dendrimers,17 so far there are no studies devoted to the
mechanical properties of dendronized polymers. Since
in our case we succeeded in synthesizing high-molecu-
lar-weight film forming dendronized polymers, it was a
unique opportunity to examine their dynamic mechan-
ical properties. Thus, the storage modules (E′) and the
loss modules (E′′) were recorded as a function of tem-
perature in the region from -50 °C and up to 80 °C.
The results for the first- and second-generation den-
dronized polyethers are presented in Figure 6. In the
case of the PETH-G1 polymers, the two transitions
previously detected during the DSC measurements are
also apparent here as two overlapping transitions. A
broad secondary transition at about 10 °C is also obvious
in most cases. On the basis of the assignment of the
two Tg’s to the side dendrons and the main chain from
DSC traces, more information can be obtained from the
DMA measurements, as far as the contribution of these
A similar behavior was observed for PETH-G2 poly-
mers during DSC measurements (Figure 4), which
presented multiple transitions during the first heating
runs of samples with no previous thermal treatment.
Regarding their glass transition temperature, it is also
probable that two Tg’s are present, though not clearly
distinguished in their DSC traces.

Macromolecules, Vol. 35, No. 15, 2002
Macromonomers and Polyethers 5813
and 1,1,2,2-tetrachloroethane with TMS as internal standard.
Gel permeation chromatography (GPC) measurements were
carried out using a Polymer Lab chromatographer with two
Ultra Styragel linear columns (104, 500 Å), UV detector (254
nm), polystyrene standards, and CHCl3 as eluent, while for
the PETH-G2 samples a Shimadzu-10A chromatographer was
also used, equipped with three Ultra Styragel linear columns
(105, 104, 500 Å), a Wyatt LS detector operating at 30°, 90°,
and 120°, and CHCl3 as eluent. Viscosity measurements of the
polymers were performed in 1,1,2,2-tetrachloroethane solu-
tions at 30 °C with an Ubbelohde-type viscometer in a Scott
Gerate AVS 310. Differential scanning calorimetry (DSC)
thermograms were obtained using an SP plus calorimeter
equipped with the Autocool accessory from Rheometrics Sci-
entific Ltd. The heating rate was 10 °C min-1, and the
temperature region was from -50 to 250 °C. DMA measure-
ments were carried out with a solid-state analyzer RSA II,
Rheometrics Scientific Ltd., at 10 Hz.
two glass transitions on the modulus of the materials
is concerned. As expected for a transition due to the side
chains, the first transition has a smaller effect on the
E′ decrease, while the second transition causes a more
pronounced decrease on the E′ value.
For the second-generation dendronized polyethers
both transitions are dependent on the flexible spacer’s
length (Figure 6b). Comparing polymers PETH-G1-x)8
and PETH-G2-x)8, we can easily notice the latter’s
lower Tg. For these poly(benzyl ether) dendrons a small
increase of the Tg has been observed with the generation
number; however, it is accepted that the variation of
Tg in the case of dendrimers can be unique, since it
simultaneously depends on a number of various fac-
tors.17 On the other hand, comparison of the main chain
Tg of these dendronized polyethers with substituted
terphenyl- or quinquephenyl-containing aromatic-
aliphatic polyethers shows a weak increase probably due
to the side dendritic moieties.19 Finally, on the basis of
the thermal and mechanical properties of these poly-
mers, we can see that, depending on the length of the
flexible spacer, there is a significant change in the
thermal properties. In all cases two low temperature
transitions are observed which can be attributed to
separately activated mobilities in the main chain and
in the dendritic side groups. These observations dem-
onstrate the effect the two side dendrons per repeating
unit impose on the mechanical properties of the final
polymers.
1,4-Di[3,5-bis(b en zyloxy)ben zyloxy]-2,5-d ib r om ob en -
zen e (4a ). A mixture of 1,4-dihydroxy-2,5-dibromobenzene (1)
(0.95 g, 3.545 mmol), 2 (3.4 g, 8.86 mmol), and K2CO3 (1.22 g,
8.86 mmol) in acetone (50 mL) was refluxed for18 h. Filtration
and washing with acetone and water gave a white solid, which
was recrystallized from toluene to give 4a as a white solid.
Yield 3 g (97%); mp 164-165 °C. Anal. Calcd for C48H40O6Br2
(872): C, 66.05; H, 4.58. Found: C, 66.18; H, 4.68. 1H NMR
(CDCl3): 5 (s, 4H), 5.05 (s, 8H), 6.57 (t, 2H), 6.7 (d, 4H), 7.13
(s, 2H), 7.29-7.38 (m, 20H). 13C NMR (CDCl3): 70.55,72.11,
102.26, 106.4, 112.0, 119.55, 127.94, 128.42, 129.0, 137.17,
138.98, 150.34, 160.59.
1,4-Di[3,5-bis(3,5-bis(ben zyloxy)ben zyloxy)ben zyloxy]-
2,5-d ibr om oben zen e (4b). A mixture of 1 (0.4 g, 1.5 mmol),
3 (3.01 g, 3.73 mmol), K2CO3 (0.515 g, 3.73 mmol), and 18-
crown-6 (0.08 g, 0.3 mmol) in acetone (70 mL) was refluxed
for 18 h. The suspension was filtrated and washed with
acetone. The solvent was evaporated under reduce pressure,
and the brownish glassy solid recrystallized from toluene to
give a white powder. Yield 2.05 g (80%); mp 112-114. Anal.
Calcd for C104H88O14Br2 (1720): C, 72.55; H, 5.12. Found: C,
Con clu sion s
Side chain dendritic aromatic-aliphatic polyethers
bearing two Fre´chet-type dendrons of the first and
second generation have been synthesized from terphen-
yldiols carrying the dendritic moieties and R,ω-aliphatic
dibromides under phase transfer polymerization condi-
tions. High molecular weights and complete monomer
consumption were detected from GPC and NMR. The
thermal and dynamic mechanical properties of the
polymers were investigated, which revealed a phase
separation tendency between the dendritic fragments
and the main polymeric chains. Two distinct Tg’s were
noticeable during DSC measurements, with the first one
attributed to the side dendrons and the second one to
the main chain. The above assignment is in agreement
with the DMA measurements of the film-forming
samples, where the former Tg had a smaller effect on
the E′ decrease while the latter one a more pronounced
effect on the loss modules. Moreover, for the PETH-G2
polymers two well-distinguished E′′ transitions were
observed in contrast to the PETH-G1 samples, pointing
out the increased effect these larger dendritic groups
impose on the polymer properties. Preliminary X-ray
characterization further supported the existence of
ordered structures, which was initially indicated by the
complexity of the DSC thermograms.
1
71.94; H, 5.3. H NMR (CDCl3): 4.98 (s, 12H), 5.03 (s, 16H),
6.55 (m, 6H), 6.67 (m, 12H), 7.12 (s, 2H), 7.28-7.42 (m, 40H).
13C NMR (CDCl3): 70.42, 70.52, 72.03, 102.02, 102.27, 106.7,
106.8, 111.87, 119.45, 127.97, 128.4, 128.98, 137.19, 138.98,
139.64, 150.3, 160.47, 160.59.
1,3-P r op a n ed iol Ester of 2-Tetr a h yd r op yr a n yloxy-4-
p h en ylbor on ic Acid (6). To a solution of 4-bromophenol (5)
(8.2 g, 47.4 mmol) and 3,4-dihydro-2H-pyran (DHP) (8.65 mL,
94.8 mmol) in 40 mL of CH2Cl2 at 0 °C was added camphoro-
sulfonic acid (CSA) (0.05 g, 0.22 mmol). The solution was
stirred at room temperature for 24 h, diluted with ether,
washed several times with water and NaOH (1 N),and dried
over MgSO4, and the organic layer evaporated to dryness. The
crude product was purified by silica gel column chromatogra-
phy with hexane/ether 5:1 as eluent to give the 2-tetrahydro-
pyranyloxy-4-bromobenzene as white crystals; mp 56-57 °C
(Commercial product mp 56-58 °C). 1H NMR (CDCl3): 1.55-2
(three m, 6H), 3.5 (m, 1H), 3.8 (m, 1H), 5.3 (t, 1H), 6.94 (d,
2H), 7.35 (d, 2H). 13C NMR (CDCl3): 19.05, 25.54, 30.65, 62.4,
96.68, 114.22, 118.7, 132.4, 156.57.
2-Tetrahydropyranyloxy-4-bromobenzene (5 g, 19.46 mmol)
was placed under a continues stream of argon in a previously
flamed round flask and diluted with THF (50 mL), distilled
prior to use. The solution was cooled to -80 °C, and a solution
of n-BuLi 1.6 M in hexane (30.4 mL, 48.64 mmol) was added
dropwise. The solution was then stirred at -40 °C for 3 h,
cooled again to -80 °C for the addition of B(OMe)3 (21.76 mL,
194.46 mmol), and afterward stirred at room temperature for
18 h. Addition of H2O (40 mL), stirring for 2 h, extraction with
ethyl acetate, evaporation of the organic layer under reduced
pressure, and subsequent work-up with hexane gave 6 as a
Exp er im en ta l Section
Ma ter ia ls. Dendrons 2 and 3,13a 1,4-dihydroxy-2,5-dibro-
mobenzene (1),20 and catalysts Pd(PPh3)4 and PdCl2(dppf)22
21
were prepared according to literature procedures. Trimeth-
ylborate was dried over lithium chloride and distilled prior to
use. Tetrahydrofuran (THF) was distilled from sodium in the
presence of benzophenone prior to use. All chemicals and
solvents were purchased from Aldrich or Merck and used
without purification unless otherwise noted. All reactions were
1
white powder.23 Yield 2.3 g (88%). H NMR (CDCl3): 1.55-2
1
carried out under an atmosphere of argon. H and 13C NMR
(three m, 6H), 3.64 (m, 1H), 3.9 (m, 1H), 5.46 (t, 1H), 6.98 (d,
2H), 7.69 (d, 2H). 13C NMR (CDCl3): 19.10, 25.58, 30.67, 62.47,
96.36, 116.19, 135.54, 137.78, 161.11.
spectra were obtained on a Bruker Avance DPX 400 and 100
MHz, respectively, spectrometer with deuterated CHCl3, DMSO,

5814 Andreopoulou and Kallitsis
Macromolecules, Vol. 35, No. 15, 2002
Compound 6 was further treated with 1.04 equiv of 1,3-
propanediol, producing the corresponding 1,3-propanediol ester
of 2-tetrahydropyranyloxy-4-phenylboronic acid.24
P ETH-G2-x)12. 1H NMR (CDCl3): 1.1-1.3 (broad, 16H),
1.65 (broad, 4H), 3.8 (broad, 4H), 4.85 (s, 8H), 4.94 (s, 4H),
4.99 (s, 16H), 6.45 (s, 2H), 6.54 (s, 8H), 6.64 (s, 8H), 6.91 (d,
4H), 7.02 (s, 2H), 7.26-7.37 (m, 40H), 7.54 (d, 4H). 13C NMR
(CDCl3): 26.47, 29.72-30.07, 68.43, 70.32, 70.47, 71.76, 101.97,
106, 106.8, 114.45, 117.23, 127.94-128.96, 130.74-131.1,
137.18, 139.66, 140.35, 150.54, 158.84, 160.29, 160.54.
2′,5′-Di[3,5-bis(ben zyloxy)ben zyloxy]-p-tr ip h en ylen e-
4′,4′′-d i(tetr a h yd r op yr a n yloxy) (7a ). To a carefully de-
gassed mixture of 4a (1.6 g, 1.84 mmol), 6 (1.63 g, 7.34 mmol),
and Pd(PPh3)4 (0.09 g, 0.078 mmol) were added toluene (25
mL) and Na2CO3 (2 M) (3.7 mL, 7.4 mmol) under a continuous
stream of argon. The mixture was vigorously stirred at reflux
for 18 h. Subsequent addition of MeOH precipitated a white
solid, which was then filtrated, washed carefully with MeOH
and hexane, and dried, providing 7a which was used without
further purification. Yield 1.8 g (92%); mp 213-215 °C. 1H
NMR (CDCl3): 1.5-2 (three m, 12H), 3.55 (m, 2H), 3.85 (m,
2H), 4.96 (d, 12H), 5.36 (t, 2H), 6.5 (t, 2H), 6.57 (d, 4H), 7.03
(s, 2H), 7.1 (d, 4H), 7.3-7.4 (m, 20H), 7.55 (d, 4H). 13C NMR
(CDCl3): 19.12, 25.6, 30.7, 62.33, 70.46, 71.7, 96.68, 102.05,
105.98, 116.4, 117.2, 127.99-128.94, 131.06-131.92, 137.28,
140.81, 150.48, 156.73, 160.4.
Ack n ow led gm en t. This work was partially sup-
ported by the Operational Programme for Education and
Initial Vocational Training on “Polymer Science and
Technology” 3.2a, 33H6, administered through the
Ministry of Education in Greece. The authors are
indebted to Prof. S. Anastasiadis and M. Lygeraki for
the X-ray measurements (FORTH-Institute of Elec-
tronic Structure and Laser, Heraklion Greece). We also
thank Prof. A. D. Schlu¨ter (F. U. Berlin) for helpful
discussions.
2′,5′-Di[3,5-bis(3,5-bis(ben zyloxy)ben zyloxy)ben zyloxy]-
p-tr ip h en ylen e-4′,4′′-d i(tetr a h yd r op yr a n yloxy) (7b). With
the same procedure as in 7a , 4b (2 g, 1.16 mmol), 6 (1.03 g,
4.64 mmol), PdCl2(dppf) (0.07 g, 0.093 mmol), THF (50 mL),
and NaOH (3 N) (4 mL, 0.012 mmol) were refluxed with
vigorous stirring for 48 h. The resulting mixture was diluted
with THF and filtrated before the addition of MeOH that
precipitated a white solid, which was then filtrated, dried, and
used without further purification. Yield 1.88 g (85%); mp 163-
165 °C. 1H NMR (CDCl3): 1.5-2 (three m, 12H), 3.55 (m, 2H),
3.85 (m, 2H), 4.9 (s, 8H), 4.98 (s, 4H), 5.04 (s, 16H), 5.35 (t,
2H), 6.52 (s, 2H), 6.58 (s, 8H), 6.68 (s, 8H), 7.05 (s, 2H), 7.12
(d, 4H), 7.3-7.45 (m, 40H), 7.55 (d, 4H). 13C NMR (CDCl3):
19.14, 25.58, 30.66, 62.38, 70.36, 70.51, 71.72, 96.72, 101.97,
102.1, 105.92, 106.84, 116.42, 117.19, 127.98-128.98, 130.99-
131.98, 137.2, 139.69, 140.33, 150.5, 156.76, 160.31, 160.55.
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2′,5′-Di[3,5-bis(ben zyloxy)ben zyloxy]-p-tr ip h en ylen e-
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1
(898): C, 80.18; H, 5.568. Found: C, 80.3; H, 5.445. H NMR
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7.03 (s, 2H), 7.28-7.4 (m, 20H), 7.43 (d, 4H). 13C NMR (DMSO-
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137.83, 140.94, 150.27, 157.49, 160.37.
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C, 78.9; H, 5.57. 1H NMR (DMSO-d6): 4.93 (s, 8H), 5.01 (s,
4H), 5.05 (s, 16H), 6.52 (s, 2H), 6.6 (s, 8H), 6.66 (s, 8H), 6.82
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116.78, 128.56-129.25, 130.37-131.36, 137.76, 140.19, 140.91,
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Gen er a l P r oced u r e for P h a se Tr a n sfer P olym er iza -
tion . A mixture of aliphatic dibromide (0.1 mmol), dendronized
macromonomer (0.1 mmol), and TBAH (0.04 mmol) was
carefully degassed before o-DCB (0.5 mL) and NaOH (10 N)
(0.5 mL) were added. The mixture is vigorously stirred at 100
°C for 18 h or up to 10 days. 1,1,2,2-Tetrachloroethane or
CHCl3 was then added, and the solution was filtrated, pre-
cipitated into a 10-fold amount of MeOH, and dried under
vacuum.
1
P ETH-G1-x)12. H NMR (TCE-d2): 1.2-1.4 (broad, 16H),
1.66 (broad, 4H), 3.8 (broad, 4H), 4.89 (s, 8H), 4.95 (s, 4H),
6.5 (s, 2H), 6.57 (s, 4H), 6.92 (d, 4H), 7.01 (s, 2H), 7.26-7.4
(m, 20H), 7.55 (d, 4H). 13C NMR (TCE-d2): 25.93, 31.13-31.4,
69.87, 71.89, 73.12, 103.55, 107.6, 115.95, 118.6, 129.4-130.47,
132.08-132.48, 138.63, 141.8, 151.9, 160.2, 161.8.

Macromolecules, Vol. 35, No. 15, 2002
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MA020255S