Hierarchical self-assembly, coassembly, and self-organization of novel liquid crystalline lattices and superlattices from a twin-tapered dendritic benzamide and its four-cylinder-bundle supramolecular polymer

Article abstract of DOI:10.1002/chem.200390114

The synthesis and structural analysis of the twin-dendritic benzamide 10, based on the first-generation, self-assembling, tapered dendrons 3,4,5- tris(4′-dodecyloxybenzyloxy)benzoic acid and 3,4,5-tris(4′-dodecyloxybenzyl- oxy)-1-aminobenzene, and the pol

Full text of DOI:10.1002/chem.200390114

FULL PAPER
Hierarchical Self-Assembly, Coassembly, and Self-Organization of Novel
Liquid Crystalline Lattices and Superlattices from a Twin-Tapered Dendritic
Benzamide and Its Four-Cylinder-Bundle Supramolecular Polymer
Virgil Percec,*[a, c] Tushar K. Bera,[a] Martin Glodde,[a, c] Qiongying Fu,[a]
Venkatachalapathy S. K. Balagurusamy,[a, b, c] and Paul A. Heiney[b, c]
Abstract: The synthesis and structural
analysis of the twin-dendritic benzamide
10, based on the first-generation, self-
assembling, tapered dendrons 3,4,5-
tris(4'-dodecyloxybenzyloxy)benzoic
acid and 3,4,5-tris(4'-dodecyloxybenzyl-
oxy)-1-aminobenzene, and the polyme-
thacrylate, 20, which contains 10 as side
groups, are presented.Benzamide 10
self-assembles into a supramolecular
cylindrical dendrimer that self-organizes
into a columnar hexagonal (Fh) liquid
crystalline (LC) phase.Polymer 20 self-
assembles into an imperfect four-cylin-
der-bundle supramolecular dendrimer,
and creates a giant vesicular supercylin-
der that self-organizes into a columnar
nematic (Nc) LC phase which displays
short-range hexagonal order.In mix-
tures of 20 and 10, 10 acts as a guest and
20 as a host to create a perfect four-
cylinder-bundle host guest supramo-
lecular dendrimer that coorganizes with
10.A diversity of Fh, simple rectangular
columnar (Fr-s) and centered rectangu-
lar columnar (Fr-c), superlattices are
produced at different ratios between 20
and 10.This diversity of LC lattices and
superlattices is facilitated by the archi-
tecture of the twin-dendritic building
block, polymethacrylate, the host guest
supramolecular assembly, and by hydro-
gen bonding along the center of the
supramolecular cylinders generated
from 10 and 20.
Keywords: dendrimers ¥ four-cylin-
der-bundle ¥ liquid crystals ¥ self-
assembly ¥ superlattices ¥
functional self-assembling dendritic building blocks,[4] and of
macromolecules based on them.[5] The supramolecular den-
drimers and dendritic macromolecules, generated from the
self-assembly of these molecular and macromolecular den-
dritic building blocks, have the shape perfection to allow self-
organization into a large variety of 2D and 3D liquid-
crystalline[4c] lattices, such as: p6mm hexagonal colum-
nar,[4a,e,g,n] c2mm rectangular columnar,[4p] various smectic
Introduction
Dendrimers, dendrons, and more complex dendritic building
blocks provided some of the most influential architectural
motifs and have had a remarkable impact on the field of
science at the interface between chemistry, biology, physics,
and complex ordered soft-condensed matter.[1 Our labora-
tory is involved in the elaboration of synthetic strategies for
the preparation of self-assembling dendrons, more complex
3]
[4f,n]
[4n, 5j, k]
phases,[4q, 6] Pm3n cubic,
Im3n cubic,
cybotactic
≈
≈
nematic phases,[6] and others.The research on the discovery
of new LC lattices from self-assembling dendritic building
blocks continues, both in our, and in other laboratories.[7]
Previously, we have reported on a novel architectural
concept and a strategy derived from it, which we believe will
provide a universal approach to the design of a diversity of
new LC superlattices.[4i] This concept is based on twin-
dendritic benzamides and polymers containing twin-dendritic
benzamide side groups.Previously, [4i] we have shown that the
simplest twin-dendritic benzamide based on the AB3 mini-
dendritic building block,(3,4,5-tris(n-alkan-1-yloxy)benzoic
acid and 3,4,5-tris(n-alkan-1-yloxy)-1-aminobenzene),[4n]
self-assembles into supramolecular cylindrical dendrimers
that self-organize into a 2D hexagonal columnar (Fh) LC
phase.The corresponding polymethacrylate containing the
same twin-dendritic side-groups self-assembles into a three-
[a] Prof.V.Percec, Dr.T.K.Bera, Dr.M.Glodde, Q.Fu,
Dr.V.S.K.Balagurusamy
Roy & Diana Vagelos Laboratories
Department of Chemistry, University of Pennsylvania
Philadelphia, 19104-6323 (USA)
Fax : (‡1)215-573-7888
E-mail: percec@sas.upenn.edu
[b] Dr.V.S.K.Balagurusamy, Prof.P.A.Heiney
Department of Physics and Astronomy
University of Pennsylvania
Philadelphia, 19104-6323 (USA)
[c] Prof.V.Percec, Dr.M.Glodde, Dr.V.S.K.Balagurusamy,
Prof.P.A.Heiney
Laboratory for Research on the Structure of Matter
University of Pennsylvania
Philadelphia, 19104-6323 (USA)
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V.Percec et al.
FULL PAPER
cylinder-bundle supramolecular dendrimer, which self-organ-
izes into a nematic phase.The co-assembly of the 20 and
60 mol% of twin-dendritic benzamide, with up to 80 mol% of
the three-cylinder-bundle supramolecular dendrimer, pro-
duced a novel hexagonal columnar LC superlattice.[4i]Hydro-
gen bonding along the center of the supramolecular column is
an important structural parameter that determines the self-
assembly and coassembly of these twin-dentritic building
blocks.This result was rewarding, since it demonstrated the
potential use of this new and simple concept for the
elaboration of other novel LC superlattices from twin-
columnar superlattice (Fr-c), and a Fh lattice.During these
co-assembly processes, the four-cylinder-bundle supramolec-
ular dendrimer undergoes structural changes from a vesicular
supercylinder, generated from an imperfect to a perfect four-
cylinder bundle supramolecular dendrimer.The transition
from an imperfect four to a perfect four-cylinder-bundle
supramolecular dendrimer is facilitated by the host guest
interactions between the empty spaces of the imperfect four-
cylinder bundle, which acts as a host, and the twin-dendritic
benzamide, which acts as a guest.The diversity of novel
architectural motifs and superlattices reported here demon-
strates that the twin-dendritic benzamide concept has great
potential to contribute to the enrichment of functional
complex and ordered soft condensed matter, derived from
self-assembling dendritic building blocks.[8]
dendritic building blocks.In our laboratory we have access
[4n]
to a library of self-assembling dendrons;
therefore,
strategies derived from symmetric twin-, and asymmetric di-
dendritic building blocks, based on this library, could provide
easy access to novel dendritic architectural motifs, without
using the synthetic effort involved in the design and prepa-
ration of novel self-assembling dendrons.
Results and Discussion
This present publication is the second on this topic and
addresses the generality and universality of this concept.
Therefore, in the series of experiments reported here we have
employed the second most frequently studied, AB3 first
generation self-assembling dendrons (3,4,5-tris(4'-dodecyloxy-
benzyloxy)benzoic acid and
Synthesis of twin-dendritic benzamide 10 and twin-dendritic
benzamide monomer 19: Schemes 1 and 2 show the synthesis
of the twin-dendritic benzamide N-[3,4,5-tris(4'-dodecyloxy-
benzyloxy)phenyl]-3,4,5-tris(4'-dodecyloxybenzyloxy) benz-
H3CO
H3CO
HO
H3CO
3,4,5-tris(4'-dodecyloxybenzyl-
i
ii
oxy)-1-aminobenzene) in our
NO2
HO
NO2
H3CO
laboratory[4a,e,g,n] to synthesize
H3CO
2, 33 %
HO
H3CO
the corresponding twin-den-
1
3, 69 %
dritic benzamide and polyme-
thacrylate, containing the twin-
dendritic benzamide as side
groups.As expected, the new
twin-dendritic benzamide re-
ported here self-assembles into
H(CH2)12O
a
supramolecular cylindrical
O
O
3
dendrimer, which self-organiz-
es into a Fh LC lattice by
similar principles to those pre-
viously reported.
H(CH2)12
O
CH2Cl
H(CH2)12O
O
NO2
iii
4
[4i]
Its corre-
sponding polymer self-assem-
bles into an imperfect four,
rather than a three-cylinder-
bundle supramolecular den-
drimer, as the previous system
did.[4i] The imperfect four-cylin-
H(CH2)12
O
5, 76 %
der-bundle
supramolecular
H(CH2)12O
dendrimer resembles a vesicu-
lar supercylinder that self-or-
ganizes into a columnar nem-
atic (Nc) phase and displays
short-range hexagonal order.
Co-assembly of the twin-den-
dritic benzamide with its corre-
sponding polymer provides, de-
pending on the molar ratio
between the two components,
a Fh superlattice, a simple-rec-
tangular columnar superlattice
O
O
iv
H(CH2)12
O
5
O
NH2
H(CH2)12
O
6, 82 %
Scheme 1.i) CH 2Cl2, SiO2 ¥ HNO3, 208C; ii) Py ¥ HCl, 2008C, 1 h; iii) K2CO3, DMF, 708C ; iv) NH2NH2 ¥ H2O,
(Fr-s),
a centered-rectangular
graphite, EtOH, reflux.
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Liquid Crystalline Lattices and Superlattices
921 935
yield; Scheme 2).[4a] Amidation
H(CH2)12O
of 9 with 6 was carried out
under
neutral
conditions
(DCC/DPTS)[5d] to produce 10
in 87% yield.
HO
O
O
O
4
H(CH2)12O
O
HO
The synthesis of monometha-
crylate functionalized twin-
dendritic benzamide monomer
19 is outlined in Scheme 3 and
4.The first step requires the
protection of two phenol
groups from the 4- and 5-posi-
tions of methyl gallate (7)
(Scheme 3).The cleavage of
the protecting group had to be
performed under neutral con-
ditions, since the benzyl ether
group of 13 does not tolerate
acidic conditions.A benzo[1,3]-
dioxole group was employed
for this purpose.[13] This protect-
ing group was cleaved under
neutral conditions without af-
fecting the integrity of the ben-
zyl ether group from 13.Thus,
2-ethoxy-7-hydroxybenzo[1,3]-
dioxole-5-carboxylic acid meth-
yl ester (11) was synthesized in
57% yield by condensing ethyl
ortho-ester with 7 in the pres-
ence of Amberlyst-120 resin as
a catalyst at 1308C for 18 h.The
hydroxy group of 11 was sub-
sequently etherified with 4-(11-
hydroxyundecyloxy)benzyl
O
i
OCH3
OCH3
HO
7
H(CH2)12
O
8, 90 %
H(CH2)12O
O
O
ii, iii
H(CH2)12
O
O
8
O
OH
H(CH2)12
O
9, 96 %
H(CH2)12
O
O(CH2)12
H
O
O
H(CH2)12
O
O
N
O
6
O
9
O
iv
O(CH2)12
H
H
O
chloride (12) in DMF at 708C,
by using K2CO3 as a base to
H(CH2)12
O
O(CH2)12H
10, 87%
Scheme 2.i) K 2CO3, DMF, 708C; ii) KOH/H2O, EtOH; iii) HCl, THF; iv) DCC, DPTS, CH2Cl2.
yield
2-ethoxy-7-[4'-(11'-hy-
droxyundecyloxy)benzyloxy]-
benzo[1,3]-dioxole-5-carboxylic
acid methyl ester (13) in 72%
amide (10).1,2,3-Trimethoxybenzene ( 1) was nitrated with
yield.The dioxole protecting group was cleaved in SiO by
2
[4i, 8 11]
HNO3 supported on SiO2
at 208C for 15 minutes to
refluxing MeOH to produce 3,4-dihydroxy-5-[4'-(11'-hydrox-
yundecanoxy)benzyloxy]methyl benzoate (14) in 91% yield.
In the subsequent step (Scheme 3), the alkylation of 4 with 14,
using similar conditions (K2CO3/DMF) to those employed in
the synthesis of 5, yielded 3,4-bis(4'-dodecyloxybenzyloxy)-5-
[4'-(11'-hydroxyundecyloxy)benzyloxy]methyl benzoate (15)
in 79% yield.The basic hydrolysis of 15 with aqueous KOH in
refluxing MeOH yielded the corresponding benzoic acid 16 in
91% yield.Compound 16 was esterified with methacryloyl
chloride using Et3N in CH2Cl2 at 0 58C to produce the
methacrylate-functionalized twin-dendritic monomer 3,4-
bis(4'-dodecyloxybenzyloxy)-5-[4'-(11'-methacryloxyundecy-
loxy)benzyloxy]benzoic acid (18).The intermediate, mixed
benzoic methacryloyl anhydride (17), was hydrolyzed with Py/
H2O at 1308C (Scheme 4).Amidation of 18 with 6 was carried
out in THF at 208C by using DCC/DPTS[5d] to produce the
monomethacrylate functionalized twin-dendritic benzamide
produce 3,4,5-trimethoxy-1-nitrobenzene (2) in 33% yield.
This nitration procedure eliminates the oxidative demethyla-
tion and selectively places the nitro group at the 5-position of
1.[4i, 10, 11] Demethylation of 2 with Py ¥ HCl salt in melt state
(2008C) for 1 h produced 3,4,5-trihydroxy-(1-nitrobenzene)
(3) in 69% yield.Compound 3 was alkylated with 4-dodecyl-
oxy(benzyl chloride) (4) by using anhydrous K2CO3 as a base
in DMF at 708C to produce 3,4,5-tris(4'-dodecanoxybenzyl-
oxy)-1-nitrobenzene (5) in 76% yield.Reduction of 5 with
12]
NH2NH2 ¥ H2O over graphite powder[4i, 10
in ethanol gen-
erated 3,4,5-tris(4'-dodecyloxybenzyloxy)-1-aminobenzene
(6) (82% yield).
3,4,5-Tris(4'-dodecyloxybenzyloxy) benzoic acid (9) was
synthesized by the alkylation of methyl-3,4,5-trihydroxyben-
zoate (methyl gallate) (7) with 4, followed by the hydrolysis of
the resulting compound 8 with KOH in EtOH at reflux (96%
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V.Percec et al.
FULL PAPER
done by a combination of XRD and TOPM according to
standard methods employed in our laboratory.[4i,n]
C2H5O
HO
O
O
O
i
HO
O
Table 1 summarizes the transition temperatures and the
corresponding enthalpy changes for 10, 19, and 20.Both twin-
dendritic benzamides 10 and 19 exhibit an enantiotropic
hexagonal columnar (Fh) liquid crystalline (LC) phase.In
both cases, the Fh phase was confirmed by XRD.The degree
of supercooling of Ti-Fh is, as expected, low: 98C for 10 and
7.5 8C for 19.Introduction of a methacryloyl group on the
periphery of 10 decreases the thermal stability of the
mesophase and reduces the isotropization temperature of 19
by 148C.This destabilization is due to the unsymmetric
substitution of 19 (Table 1).
OCH3
HO
OCH3
HO
7
11, 57 %
C2H5O
O
HO(CH2)11
O
CH2Cl
O
12
O
11
OCH3
ii
O
During heating, polymer 20 exhibits an LC phase that
undergoes isotropization at 1638C.A columnar nematic ( Nc)
LC phase was assigned by a combination of TOPM and XRD
studies for this phase.A detailed discussion of the XRD
analysis will be presented later.Due to the slow dynamics of
polymer 20, the isotropization peak is not seen during the
second heating and cooling DSC scans.However, on all
heating and cooling scans, the isotropization temperature was
detected by TOPM and XRD experiments.
HO(CH2)11
O
13, 72%
HO
O
HO
iii
OCH3
13
O
14, 91 %
HO(CH2)11
O
Structural analysis of 10, 19, and 20: Powder samples of 10, 19,
and 20 were studied both at room temperature, and in the
temperature range over which they form the LC phase.In the
work described here, we use the convention q ˆ (4p/l) ¥
sin(q) ˆ 2p/d, in which 2q is the scattering angle and d is the
interplanar spacing.Due to the appearance of weaker peaks
on top of the diffuse scattering, and the background scatter-
ing, the peak positions were determined after curve fitting all
the diffraction patterns.Figure 1 shows the powder diffraction
patterns of 10, 19, and 20.
H(CH2)12
O
O
4
14
H(CH2)12
O
O
O
iv
OCH3
O
Structural analysis of twin-dendritic benzamide 10: The twin-
tapered dendritic molecule 10 exhibits one strong and one
weak, but sharp, diffraction peak in the LC phase (20/10
(0:100) in Figure 1; Table 2).The calculated ratio of the
HO(CH2)11
O
15, 79 %
Scheme 3.i) (EtO) 3CH, Amberlyst-120, 1308C, 18 h; ii) K2CO3, DMF,
708C; iii) SiO2, MeOH, reflux, 24 h; iv) K2CO3, DMF, 708C.
interplanar spacing of the strong peak to that of the weak
p
peak is d10/d11 ˆ 1.70 (ꢀ 3).Thus, these peaks arise from the
N-[3,4,5-tris(4'-dodecanoxybenzyloxy)phenyl]-3,4-bis(4'-do-
decanoxybenzyloxy)-5-[4'-(11'-methacryloxyundecanoxy) benz-
yloxy]benzamide (19), in 70% yield after purification by
column chromatography (SiO2, hexanes/EtOAc 9:1).
Fh lattice formed by the twin-dendritic supramolecular
cylinder self-assembled from 10 and were indexed as (10)
and (11).The (10) peak is superimposed on a relatively weak
diffuse maximum at approximately the same peak position.
This diffuse scattering cannot arise from any static structural
disorder, since it does not show any noticeable change upon
annealing at high temperature.Most probably, it arises from
column undulations like that observed in the Fh phases
obtained from discotic molecules, such as alkoxy-substituted
triphenylene.[14] The (11) peak does not show any detectable
diffuse scattering underneath.Additionally, a very broad
diffuse peak in the wide angle was observed; this corresponds
to the liquidlike short-range order of the melted alkyl tails.
The simplified molecular model of 10 containing only
methoxy tails, generated with the aid of the Macro Model
version 6.5 software (Columbia University) on a Silicon
Graphics O2, is shown in Figure 2 (middle section).The twin-
dendritic benzamide 10 produces a criss-crossed stack as
illustrated in the top view of the model (Figure 2, mid right).
Polymerization of 19: Radical polymerization of 19 initiated
by AIBN was carried out under N2 in benzene at 608C
(Scheme 5) for 18 h to achieve a high conversion (93%).The
resulting polymer was purified by column chromatography
(Al2O3, hexanes) to separate the unreacted monomer. Mn ˆ
49.813 and Mw/Mn ˆ 1.62 (GPC with polystyrene standards).
Thermal analysis of 10, 19, and 20: All compounds were
analyzed by a combination of differential scanning calorim-
etry (DSC), thermal optical polarized microscopy (TOPM),
and X-ray diffraction (XRD) experiments.The transition
temperatures and the corresponding enthalpy changes
(kcalmolÀ1) were determined by DSC with a heating/cooling
rate of 108C minÀ1.The assignment of various phases was
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Liquid Crystalline Lattices and Superlattices
921 935
H(CH2)12O
H(CH2)12O
O
O
O
H(CH2)12O
i, ii
O
H(CH2)12O
O
O
iii
CH3
C
O
O
15
CH2
OH
CO
O
CH3
H2C
HO(CH2)11
O
O
CO2-(CH2)11
C
16, 91%
17
H(CH2)12
O
H(CH2)12O
O(CH2)12H
O
O
iv
6
H(CH2)12O
O
O
16
H(CH2)12
O
O
O
O
O
v
O
H
N
O
O
O
O(CH2)12
H
H
CH3
CH3
H2C
O
CO2-(CH2)11
C
H2C
O
C
CO2-(CH2)11
O(CH2)12
H
18, 75%
19, 70%
Scheme 4.i) KOH/H 2O, EtOH; ii) HCl, THF; iii) methacryloyl chloride, CH2Cl2, Et3N; iv) pyridine/H2O, 1308C; v) DCC, DPTS, THF.
H(CH2)12O
in a crystal, but has some devi-
ation from the crystallike order
in terms of the intermolecular
separation, and the orientation
of similarly oriented molecules.
This disorder is indicative of the
liquidlike short-range order
along the cylinders present in
a 2D Fh LC phase.The average
separation of similarly oriented
molecules 10 in this stack is
7.2 ä.
O(CH2)12H
O
O
i
H(CH2)12O
O
O
O
19
O
N
O
O(CH2)12
H
H
CH3
CH2
C
n
O
CO2(CH2)11
O(CH2)12
H
The lattice parameter of the
Fh phase of 10 is a ˆ 34.1 ä
(Figure 2, bottom).This value is
significantly smaller than the
length of 10, 56.5 ä, which has
a fully extended all-trans con-
formation of its alkyl tails.This
difference is due to the shrink-
20
Mn = 50,000
Mw/Mn = 1.6
Scheme 5.i) Benzene, AIBN, 60 8C, 93%.
The stack was subjected to energy minimization by using a
MM2 molecular force field without enforcing periodic
age of alkyl tails through a mixture of trans and gauche
conformers in the Fh LC phase.[4i] The measured cylinder
diameter, 34.1 ä, shows that there is a 76% reduction in the
all-trans length of the alkyl tails in the LC phase.The number
of molecules (m) within a 7.2 ä stratum of the cylinder,
calculated from the experimental density (120) of 10 and its
diameter, determined by XRD, is 2.2 (Table 2). Thus, a single
cylinder is formed by the criss-cross stacking of twin-dendritic
benzamide 10 along the center of the cylinder by the
boundary conditions along the stack.By replacing the C
12
chain with a methyl group, the calculated diameter of the rigid
aromatic region of a cylinder formed by 10, is 28.2 ä.
Compound 10 forms hydrogen bonds between the amide
groups along the center of the stack at a distance in the range
of 1.9 2.2 ä (Figure 2, mid left). It was further found that the
stack does not form a very regular cylinder of molecules, like
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Table 1.Thermal characterization of 10, 19, 20, and of the binary mixtures of 20
with 10 by DSC.
20/10
Phase transitions [8C] and
corresponding enthalpy changes [kcalmolÀ1
Cooling[a]
]
mol/mol
100/0
Heating[a]
k 64 (2.3) k 119 (0.15) Nc 163 (1.0) i
k 56 (1.8) Nc 171[b] i
k 73 (1.2) k 112 (0.17) Nc 164 (0.6) i
k 57 (5.0) Nc 173[b] i
i 162[b] Nc 54 (2.0) k
i 163[b] Nc 48 (2.16) k
i 166[b] Fh 46 (2.0) k
90/10
80/20
70/30
60/40
50/50
40/60
30/70
20/80
10/90
0/100
19
k 70 (1.2) k 108 (0.25) Fh 165 (1.2) i
k 53 (5) Fh 177[b]
i
k 66 (2.8) k 106 (0.3) Fh 166 (1.03) i
k 67 (5.7) Fh 153[b]
k 83 (3.2) k 102 (0.34) Fr-s 166 (1.2) i
k 84 (4.5) Fr-s 159[b]
k 87 (6.0) Fr-c 168 (1.1) i
k 73 Fr-c 176[b]
k 90 (7.8) Fr-c 170 (1.34) i
k 61 (2.2) Fr-c 167[b]
k 93 (8.9) Fh 173 (1.3) i
k 60 (3.5) Fh 165[b]
i 136[b] Fh 45 (1.62) k
i
[b]
i 146
i 168
i 156
F
r-s
F
r-c
F
r-c
70 (2.5) k
70 (2.0) k
67 (3.8) k
i
[b]
[b]
i
i
i 152[b] 66 (1.7) k
i
k 95 (9.9) Fh 173.5 (1.66) i
k 90 (0.5) Fh 149 (0.67) i
k 98 (11) Fh 175 (1.85) i
i 145 (0.92) Fh 71 (0.6) k
i 156 (0.8) Fh 72 k
k 75 (À5) k 94 (5.5) Fh 161 i
k 103 (13) Fh 178 (1.75) i
i 169 (1.63) Fh 73 (0.8) k
i 156 (1.4) Fh 53 (9.0) k
k 60 (À8) k 100 (11) Fh 172 (1.66) i
k 57 (20.8) k 93 (11) Fh 163.5 (2.0) i
k 92 (10.5) Fh 160.5 (1.53) i
Figure 1.XRD patterns of 10, 19, 20, and of 20/10 mixtures (mol/molÀ1).
[a] Data from the first heating and cooling scans are on the first line.Data from
the second heating scan are on the second line.[b] Determined by TOPM as
onset temperature of phase transition; k ˆ crystalline, Nc ˆ nematic columnar,
i ˆ isotropic, Fh ˆ hexagonal columnar, Fr-s ˆ simple rectangular columnar,
Fr-c ˆ centered rectangular columnar.
are nearly identical to those observed in the diffraction
pattern of 10 (Figure 1).Thus, compound 19 forms a 2D Fh
LC phase with a column diameter of a ˆ 35.4 ä at Tˆ 988C.
The diameter of the supramolecular cylinder generated from
19 is nearly identical to that of the cylinder generated from 10.
However, the intensity of the diffuse scattering is, interest-
ingly, much smaller relative to that of the sharp (10) peak.
Hence, the molecular organization within the supramolecular
cylinders generated from 19 must be similar to that within the
supramolecular cylinders generated from 10, except for the
difference in the feature that gives rise to the diffuse
scattering around the strong (10) peak.Similarly, this diffuse
scattering arises from dynamic rather than static disorder.
formation of the hydrogen bonds.The alkyl chains shrink to
fill the space around the twin-tapered aromatic core, and
produce the well-defined cylinder, which self-organizes into
the 2D hexagonal columnar lattice (Figure 2, bottom).This
model is similar to that previously reported for a related twin-
dendritic benzamide.[4i, 15]
Structural analysis of twin-dendritic monomer 19: The
diffraction pattern of monomer 19 shows sharp peaks that
Table 2.XRD data for 19, 10, 20, and for the binary mixtures of 20 with 10.
LC phase
(T [8C])
Peak d spacings [ä] and their indices[a]
a [ä][b]
Dcol[ä][c]
Rhombic unit cell
surface area [ä2][d]
1 [gcmÀ3
]
m[e]
d10
d11
d20
d21
d31
10
19
20
Fh(94)
Fh(98)
Nc(86)
29.2
(s)
30.7
(s)
17.2
(vw)
17.6
(vw)
32.6
(s,b)
34.1 Æ 0.5
35.4 Æ 0.2
65.6 Æ 0.5
70 Æ 3
34.1 Æ 0.5
35.4 Æ 0.2
65.6 Æ 0.5
35.1 Æ 0.4
35.2 Æ 0.5
34.7 Æ 0.2
34.8 Æ 0.1
p
1007
1085
3727
4244
4490
4366
1049
0.93
2.2
[f]
57.1
(w,b)
58.2
(w,b)
58.2
(w,b)
62.8
(w,b)
30.2
(s)
24.6
(v,b)
0.84
0.91
6.8
2.1
20/10
(80:20)
20/10
(70:30)
20/10
(30:70)
20/10
Fh(127)
Fh(128)
Fh(115)
Fh(115)
30.6
(s)
30.7
(s)
30.2
(s)
17.4
(vw)
17.5
(vw)
17.3
(vw)
72 Æ 2
71 Æ 2
17.4
(vw)
34.8 Æ 0.1
(20:80)
p
p
[a] The d spacing ratios are as expected for the 2D hexagonal columnar lattice, d10:d11:d20:d21:d31 ˆ 1:(1/ 3):(1/2):(1/ 7):(1/ 13).[b] a ˆ lattice dimension.
p
[c] Dcol ˆ column diameter.[d] Surface area of the rhombic unit cell of the 2D hexagonal lattice is given by ( a2 3)/2.[e] Number of molecules occupying a
single column over a 7.2 ä stratum. [f] s: strong, w: weak, vw: very weak, b: broad.
926
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Chem. Eur. J. 2003, 9, No. 4

Liquid Crystalline Lattices and Superlattices
921 935
cylinder self-assembled with
fully-extended alkyl tails.Fur-
ther, and more importantly, the
high intensity of the (11) peak
of 20 suggests that this polymer
self-assembles with its polymer
backbone in the core of the
cylinder.In other words, the
interior region of the cylinder
contains aliphatic segments of
its twin-tapered dendritic side-
groups, surrounding one or
more polymer backbones in
the central region.The exterior
of the cylinder contains only
aliphatic tails fanning out from
the twin-tapered dendritic side
groups, with the space between
the exterior, and interior occu-
pied by the aromatic region.
Hence, the polymer backbone
drives the formation of a vesic-
ular arrangement of the mole-
cules in a cylinder that subse-
quently self-organize into an Nc
phase with short-range hexago-
nal arrangement (Figure 4).It
can now be seen that the (10)
peak in the diffraction pattern
of 20 arises due to the polymer
backbone segregated in the
core of the vesicular supercy-
linders.
Figure 2.Schematic representation of the self-assembly of 10 into supramolecular cylindrical dendrimers that
self-organize in a Fh lattice.The surface of the supramolecular cylinder is liquidlike.The exaggerated order of the
supramolecular cylinder is shown to illustrate the mechanism of self-assembly.This schematic pattern is used in all
figures of this manuscript.
It may be noted that the
experimental density of poly-
mer 20 (120 ˆ 0.84 gcmÀ3, Ta-
ble 2) is lower than that of the
twin-tapered dendrimer 10
Structural analysis of polymer 20: In contrast to 10 and 19,
polymer 20 shows only very broad peaks in the XRD pattern.
In the diffraction pattern of 20, a strong peak with d ˆ 32.6 ä
(q ˆ 0.193 äÀ1), a weak peak with d ˆ 57.1 ä (q ˆ 0.110 äÀ1),
and a very weak peak with d ˆ 24.6 ä (q ˆ 0.255 äÀ1) are
observed (20/10 (100:0) in Figure 1; Table 2).These peaks
were indexed to the (11), (10), and (21) reflections of a 2D
(120 ˆ 0.93 gcmÀ3).Since polymer 20 has short-range hexag-
onal arrangement in the Nc phase, its unit cell is the same as
the rhombic unit cell of the hexagonal lattice.The surface area
of the unit cell is 3a2/2, in which a is the lattice dimension.
p
p
p
hexagonal lattice as their ratio is d10:d11:d21 ꢀ1:(1/ 3):(1/ 7).
The broadness of the peaks indicates that this 2D hexagonal
lattice has only short-range structural order.These peaks did
not sharpen, even after long annealing at high temperature,
suggesting that their broadness is intrinsic to the structure of
the LC phase.This behavior is also consistent with the texture
observed by TOPM, which suggests that 20 forms a columnar
nematic (Nc) phase.A characteristic texture of the Nc phase of
20 is shown in Figure 3.
The average lattice dimension a, calculated from the peak-
positions of 20, is 65.6 ä. This value is slightly smaller than
double of the corresponding values for 10 and 19 in their Fh
phase (Table 2).The a value of 20 is also significantly larger
than the molecular diameter calculated for a supramolecular
Figure 3.Optical polarized micrograph of the Nc mesophase of 20
observed at 328C on cooling with 0.58C minÀ1 from isotropic melt.
Chem. Eur. J. 2003, 9, No. 4
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927

V.Percec et al.
FULL PAPER
In a previous study of a
polymer with the same back-
bone, but with smaller twin-
dendritic side groups, one su-
perlattice and one sublattice
reflection were observed in the
XRD pattern.These reflections
were indexed as (10) and
(20).[4i] This is in contrast to
the (10), (11), and (21) reflec-
tions observed from the present
polymer 20.Based on the XRD
features, and the above discus-
sion, it is proposed that polymer
20 exhibits the novel type of
vesicular Nc phase shown in
Figure 4.This supramolecular
structure is based on a four-
cylinder bundle, with one or
more polymer backbones in
the interior, and can pack into
an Nc phase with short-range
hexagonal order.Therefore, a
larger cylinder consisting of
more than one polymer back-
bone segregated in the center
and surrounded by a bundle of
four polymeric cylinders is pro-
duced (Figure 4).
Structural analysis of binary
mixtures of polymer 20 with
twin-dendritic benzamide 10:
Binary mixtures of 20 with 10
Figure 4.Schematic representation of the self-assembly of 20 into giant supramolecular cylindrical dendrimers
generated from imperfect four-cylinder-bundle supramolecular dendrimers that self-organize in a Nc liquid
crystalline phase with short-range hexagonal order.
(20/10 (x:y) where x:y ˆ
molmolÀ1 ratio of the repeat
unit of 20 with 10) were pre-
pared in THF and dried at 208C
The surface area of the rhombic unit cell of polymer 20
(3727 ä2) is 3.7 times larger than that of the twin-dendritic
molecule 10 (1007 ä2).This indicates that nearly four twin-
dendritic cylinders occupy the rhombic unit cell of polymer
20.The number of repeat units of 20 that occupy a 7.2 ä
stratum of a single rhombic unit cell of the short-range
hexagonal arrangement of the Nc phase, calculated using the
experimental density (120 ˆ 0.84 gcmÀ3) and the lattice di-
mension (a ˆ 65.6 ä), is 6.8 (Table 2). An attempt to arrange
the molecules of the twin-tapered dendrimer 10 into the
rhombic unit cell, with the same dimension as that of polymer
20, but with the density of 10 (120 ˆ 0.93 gcmÀ3), yields a value
of 7.5. This value is higher than the 6.8 repeat units of polymer
20 that are contained in the same unit cell.These results show
that there is some amount of empty space in the supra-
molecular cylinders that form the Nc phase of the polymer 20
as indicated by the white layers of the cylinders in Figure 4.
Therefore, this polymer has three different structural disor-
ders: the polymer backbone region located between the
supramolecular cylinders, the position of these cylinders, and
the empty space within them.
under vacuum.The thermal transitions and their correspond-
ing enthalpy changes are summarized in Table 1.All binary
mixtures exhibit homogeneous isotropizations with corre-
sponding transition temperatures lying between that of the
parent components 20 and 10.
A Fh LC phase is formed by mixtures containing more than
70 mol% of 10.Mixtures containing less than 20 mol% of 10
form an Nc phase (Table 2), and therefore, behave similarly to
the pure polymer 20.Mixtures of 20/10 containing between 20
and 70 mol% of 10 exhibit several new phases.Their structure
is dictated by the amount of 10 present in the 20/10 mixture.
Analysis of 20/10 (80:20 and 70:30): Mixtures containing 20
and 30 mol% of 10 show one strong sharp peak at d ˆ 30.6 ä
(q ˆ 0.205 äÀ1) and a very weak sharp peak at d ˆ 17.1 ä (q ˆ
0.367 äÀ1) (Table 2, Figure 1).In addition, 20/10 (80:20) and
20/10 (70:30) compositions show a broad peak of low intensity
at d ˆ 58.2 ä (q ˆ 0.108 äÀ1).The d spacings of these peaks,
p
58.2, 30.6, and 17.1 ä are in the ratio (1):(1/2):(1/ 13).This
ratio corresponds to the d10, d20, and d31 reflections of a 2D
hexagonal lattice, and, therefore, this is a 2D Fh LC phase.
928
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Chem. Eur. J. 2003, 9, No. 4

Liquid Crystalline Lattices and Superlattices
921 935
These mixtures also show diffuse scattering centered nearly at
the same position as the sharp strong peak observed in the Fh
phase of 10 (Figure 1).Therefore, the observed diffraction
pattern of 20/10 (80:20 and 70:30) is very similar to that of 10
except for the broad (10) peak at q ˆ 0.108 äÀ1 (d ˆ 58.2 ä).
The position and width of the broad peak in these mixtures is
almost the same as that observed in polymer 20.The
appearance of the sharp peaks in these 20/10 mixtures are
almost in the same position as in the case of the twin-tapered
dendritic molecule 10, and their very similar widths suggest
that the twin-tapered dendritic side groups of the polymer
molecule self-assemble easier in the presence of the twin-
tapered dendritic molecules 10.Therefore, the side-groups of
20 must co-assemble with 10, which is similar in size to the
missing side groups of 20 and fills the empty space in the
imperfect four-cylinder-bundle supramolecular dendrimer
that results from 20 (Figure 5).Therefore, during this process
20 acts as a host and 10 as a guest, and their mixtures produce
host guest complexes.When all the empty guest places of 20
occupy the core of the four-cylinder-bundles, and the twin-
tapered dendritic molecules 10 correct the structural defects,
such as, empty spaces of the disordered bundle of pure 20
(Figures 4 and 5).Also, correcting these structural defects
enables the side-groups of the polymer 20 to form well-
ordered individual cylinders through the host guest com-
plexes described above.However, the near equivalence of the
(10) peak to that seen in polymer 20 demonstrates that the
polymer backbone region of the supramolecular cylinder
continues to be as disordered as in the parent 20.A top view
of the Fh superlattice, formed by the polymer backbone
bundles of these mixtures, and the subcells formed by the
twin-dendritic cylinders are shown in Figure 6a.
Figure 6.Top views of the cross-sections of the superlattices formed by
binary mixtures 20/10 (80:20 to 40:60).
Analysis of 20/10 (60:40): There are two narrower peaks for
the mixture 20/10 (60:40) in the q ꢀ 0.1 äÀ1 region.This is in
contrast to the single broad peak observed in the same region
for 20/10 (70:30).Similarly, in the q ꢀ 0.2 äÀ1 region, there are
two slightly broader peaks rather than a single sharp peak for
the mixture 20/10 (60:40).In addition, two slightly broader
weak peaks appear at q ˆ 0.224 äÀ1 (d ˆ 28.1 ä), and q ˆ
0.252 äÀ1 (d ˆ 24.9 ä), respectively. For the same mixture,
there is a very strong peak at q ˆ 0.204 äÀ1 (30.8 ä), and a
weak peak at q ˆ 0.357 äÀ1 (17.6 ä). These two peaks occur at
almost the same position as those observed for the mixture 20/
10 (70:30).All the peaks could be indexed to a simple
rectangular superlattice Fr-s with the dimensions a ˆ 61.4 ä
and b ˆ 55.1 ä (Figure 6b). Thus, the peak with q ˆ 0.108 äÀ1
indexed as (10), in the case of 20/10 (80:20 to 70:30), becomes
two peaks in 20/10 (60:40) with the indices (10) and (01).The
index for the most intense peak is (20) and for the peak at q ˆ
0.224 äÀ1 is (02).The (20) and (02) peaks are the second order
peaks arising from (10) and (01), respectively.The fact that
the (20) peak is stronger than the (10) peak and appears at
Figure 5.Schematic representation of the co-assembly of binary mixtures
20/10 (80:20 to 70:30) into perfect four-cylinder-bundle supramolecular
dendrimers that self-organize in a Fh superlattice.
are filled with 10, the imperfect four-cylinder-bundle 20
becomes a perfect four-cylinder-bundle supramolecular den-
drimer.Subsequently, the self-organization of the four-
cylinder-bundle of 20/10 (80/20 and 70/30) mixtures forms a
Fh superlattice with a lattice dimension a ˆ 70 ä and 72 ä,
respectively.In this superlattice, the polymer backbones
Chem. Eur. J. 2003, 9, No. 4
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929

V.Percec et al.
FULL PAPER
almost the same position as the (10) peak observed in the
twin-dendrimer 10, suggests that the shapes of the individual
supramolecular cylinders forming the Fr-s phase are very
similar to those of the twin-dendrimer 10 in its Fh phase.
However, in this 20/10 (60:40) mixture (Figure 6b), the
average position of the centers of the individual cylinders
vary slightly from one unit cell to another.The ratio a/b ˆ 1.11
shows it is only slightly distorted from being a simple square
lattice.Alternatively, this structure can be considered as an
oblique lattice, with a' ˆ 61.4 ä, b' ˆ 82.5 ä, and an included
angle of a ˆ 41.98 (thin dotted line in Figure 6b).It should be
noted that the lattice dimensions of the Fr-s superlattice (a ˆ
61.4 ä and b ˆ 55.1 ä) are only slightly different from the
diameter of the supercylinder (65.6 ä) formed in the Nc phase
of polymer 20.This shows that the four-cylinder-bundles of
the polymer self-organize into the Fr-s lattice upon the
addition of 40 mol% of 10, which induces changes in the
relative positions of the supramolecular cylinders of the
dendritic units surrounding the polymer backbone.This
change favors a simple rectangular arrangement rather than
a hexagonal one, which is preferred by the pure polymer 20 in
the Nc phase, as well as by the mixtures 20/10 (80:20 to 70:30)
in the superlattice LC phase.
are the second order peaks arising from (11) and (20) peaks
respectively.Similar to 20/10 (60:40), the (22) peak is stronger
than the (11) peak and appears at almost the same position as
the (10) peak of 10; this leads again to the conclusion that the
individual supramolecular cylinders forming the Fr-c phase are
very similar to those of the twin-dendrimer 10 in its Fh phase.
The ratio of the centered rectangular lattice dimensions a/b is
p
1.54. This value is close to the value 3, expected for an
undistorted hexagonal lattice indexed to a centered rectan-
gular lattice.Alternatively, this structure can be considered as
an oblique lattice with a' ˆ b' ˆ 67.7 ä and an included angle
of a ˆ 66.18 (thin dotted line in Figure 6c).The angle a ˆ 66.18
corresponds to only a slight distortion of a ˆ 60.08 which is the
ideal value for an undistorted hexagonal lattice.In other
words, the Fr-c superlattice of 20/10 (55:45 to 50:50) can be
considered as the distorted version of the columnar hexagonal
superlattice, exhibited by 20/10 (80:20 and 70:30).
Analysis of 20/10 (40:60): The diffraction pattern of the
mixtures 20/10 (40:60) is very similar to that of 20/10 (60:40).
Thus, all the peaks were indexed to a simple rectangular
superlattice (Fr-s ; Figure 6b with the lattice dimensions a ˆ
60.9 ä and b ˆ 54.9 ä, with the same indices for the corre-
sponding peaks.Therefore, the supramolecular self-organiza-
tion is very similar to that for the mixture 20/10 (60:40).
Analysis of 20/10 (55:45 and 50:50): The 20/10 mixtures
containing from 45 to 50 mol% of 10 (i.e., 0/10 (55:45 to
50:50)) exhibit more diffraction peaks than the mixtures
containing 40 mol% of 10 (i.e., 20/10 (60:40), Table 3, Fig-
ure 1).The intensity of the additional peaks increases as the
concentration of 10 increases from 45 to 50 mol%.We discuss
the diffraction results for 20/10 (50:50), since its peaks are
most prominent in the XRD pattern.The diffraction pattern
of 20/10 (50:50) shows two close peaks at q ꢀ 0.1 äÀ1 ((11) and
(20) in Figure 1), which are narrower than the single broad
(10) peak observed in 20/10 (70:30).The peak positions of 20/
10 (50:50) are indexed to a centered rectangular (Fr-c)
superlattice with dimensions a ˆ 113.5 ä and b ˆ 73.8 ä (Fig-
ure 6c).The indices for the peaks with q ꢀ 0.1 äÀ1 are (11) and
(20), and the most intense peaks are indexed as (22) and (40).
These most intense peaks occur nearly at the same position as
the strong (10) peak observed for 10.The (22) and (40) peaks
Analysis of 20/10 (30:70): Most of the reflections observed in
20/10 (60:40 to 40:60) are not observed in 20/10 (30:70)
(Table 2, Figure 1).Instead 20/10 (30:70) exhibits only a single
broad peak at q ˆ 0.100 äÀ1 ((10) peak for 30:70 mixture in
Figure 1), at nearly the same position as that observed in 20/10
(60:40 to 40:60).However, the (10) peak of 20/10 (30:70)
becomes narrower and is shifted towards lower q values than
the (10) peak observed in the same region for the mixtures of
20/10 (80:20 and 70:30), as well as for the polymer 20 (20/10
(100:0) in Figure 1).In addition to the broad (10) peak, 20/10
(30:70) shows sharp peaks at q ˆ 0.208 äÀ1 and q ˆ 0.363 äÀ1.
They are nearly at the same position as those observed in 20/
10 (70:30).The d10 ˆ 62.8 ä (q ˆ 0.100 äÀ1) peak of 20/10
(30:70) is about 7% larger than the d spacing of the (10) peak
of 20/10 (70:30), and is also narrower.This suggests that the
Table 3.XRD data for the binary mixtures of the polymer 20 with 10 in the centered rectangular columnar (Fr-c) and simple rectangular columnar
(Fr-s) LC phases.
LC phase (T [8C])
Peak d spacings [ä] and their indices
a and b[c]
[ä]
1
m[d]
[a]
[b]
[a]
[b]
[a]
[a]
[a]
[a]
[b]
d10
d11
d01
d20
d20
d22
d02
d40
d12
d13
d13
d24
[gcmÀ3
]
[b]
[b]
[b]
[b]
[b]
[b]
[b]
d02
d31
d42
d51
[e]
20/10
(60:40)
20/10
(55:45)
20/10
(50:50)
20/10
Fr-s
62.2
62.2
62.8
62.2
55.1
55.1
56.1
54.6
30.8
30.5
30.8
30.7
28.1
28.8
28.6
28.1
24.9
24.5
24.5
24.5
17.6
17.7
17.5
17.6
a ˆ 61.4
b ˆ 55.1
a ˆ 113.0
b ˆ 74.3
a ˆ 113.5
b ˆ 73.8
a ˆ 60.9
b ˆ 54.9
(115)
[f]
Fr-c
36.7
22.3
0.91[g]
0.91
--
2.1
2.0
(121)
[f]
Fr-c
33.6
21.7
(121)
[e]
Fr-s
(40:60)
(121)
[a] d spacings with indices for simple rectangular columnar LC superlattice (Fr-s).[b] d spacings with indices for centered rectangular columnar LC
superlattice (Fr-c).[c] Lattice dimensions.[d] Number of molecules occupying a single column over a 72. ä stratum.[e] For the simple rectangular lattices
reported here, the d spacing ratios are (within 2%): d10:d01:d20:d02:d12:d13 ˆ 1.00:(1/1.13):(1/2.02):(1/2.22):(1/2.50):(1/3.54). [f] For the centered rectangular
lattices reported here, the d spacing ratios are (within 2%): d11/d20/d02/d31/d22/d40/d13/d51/d24 ˆ 1.00:(1/1.09):(1/1.67):(1/1.83):(1/1.99): (1/2.18):(1/2.56):
(1/2.84):(1/3.51). [g] The density is assumed to be 0.91 gcmÀ3, since the measured density for the mixtures containing 50 mol% and 70 mol% of 10 are the same.
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Liquid Crystalline Lattices and Superlattices
921 935
lower concentration of polymer 20 in 20/10 (30:70) increases
the average distance between the polymer backbone bundles.
The regions occupied by the polymer backbone are less
disordered than in the mixtures containing larger amounts of
20.It is conceivable that the number of polymer strands varies
along the center of the supramolecular cylinders (Figure 7b)
resulting in regions of empty space that are filled by short
distribution of polymer 20, which is very similar in size and
shape to 10, and replaces 10 in its lattice.Since polymer 20
does not form any ordered superlattice structure, it destabil-
izes the isotropization temperature of the mixture 20/10
(20:80) by 24.58C during the second heating scan of the DSC
(Table 1).
In summary, the LC phase behavior of the binary mixtures
of the polymer 20 with the twin-tapered dendritic benzamide
10 (20/10 (x:y)) follows the composition trend shown in
Figure 8: for y < 20: Nc, 20 ꢁ y ꢁ 30: Fh superlattice, formed
by four-cylinder-bundle supramolecular dendrimer 20; for
30 < y < 45: Fr-s superlattice, formed by distorted four-cylin-
der-bundle supramolecular dendrimer 20; for 45 ꢁ y < 60: Fr-c
superlattice; for 60 ꢁ y < 70: Fr-s superlattice; for 70 ꢁ y <
80 < : Fh superlattice, and for y ꢂ 80 Fh lattice with no
superlattice ordering.
Figure 8.Hierarchical formation of lattices and superlattices self-organ-
ized and co-organized from the supramolecular architectures generated
from 10, 20, and from mixtures 20/10 (x:y) and their thermal stability range.
Figure 7.Schematic representation of the self-assembly of binary mixtures
20 (30:70) into a Fh superlattice, either by maintaining the four-cylinder-
bundle supramolecular dendrimers, but with having larger regions of 10 in
the individual cylinders (a/b) or by a combination of a three-cylinder-
bundle supramolecular dendrimer polymer and non-uniformly distributed
individual dendritic cylinders (c).
Conclusion
stacks of twin-dendritic benzamide 10 (Figure 7a).Thus, the
mixture 20/10 (70:30) forms a Fh superlattice with a lattice
dimension double that of the pure 10.Alternatively, this can
be viewed as a result of displacing one or two polymer strands
along the center of the supramolecular cylinders by a certain
distance, which would create empty regions in the cylinders
that can be filled by short stacks of 10.At low enough
concentrations of polymer 20, this can give rise to the repeat
units of the polymer 20 occupying only three neighboring
columns surrounding the backbones (Figure 7c).
The twin-dendritic benzamide 10 self-assembles into supra-
molecular cylinders that self-organize in a Fh lattice.The
same twin-tapered dendritic molecules attached to a poly-
methacrylate backbone (20) and self-assemble into an im-
perfect four-cylinder-bundle supramolecular dendrimer that
forms a novel giant vesicular supercylinder that self-organizes
in a Nc phase with short range hexagonal order.The imperfect
four-cylinder-bundle supramolecular dendrimer 20 serves as a
host to form long-range ordered hexagonal and different
types of rectangular columnar 2D superlattices when it is
mixed with 10, which acts as a guest.The host guest complex
of 20 with 10 generates a perfect four-cylinder-bundle supra-
molecular dendrimer.The Fh superlattice contains disordered
regions of segregated polymer backbones, while the Fr-s and
Fr-c superlattices contain less disordered regions of segregated
polymer backbones.The nature of the superlattices formed is
determined by the concentration of 10 in the 20/10 mixtures.
The concept used to generate these novel superlattices can be
elaborated to design novel functional and complex ordered
soft condensed matter with potential applications in surface
Analysis of 20/10 (20:80): Once the concentration of the twin-
tapered dendrimer 10 in the mixture reaches 80 mol% (i.e. 20/
10 (20:80)), we no longer observe any features in the q ꢀ
0.1 äÀ1 region.Only two sharp peaks at q ˆ 0.208 äÀ1 and q ˆ
0.361 äÀ1 are observed.They are at almost the same position
as in the case of the twin-tapered dendrimer 10.The polymer
20 concentration is insufficient to form an ordered super-
lattice, and, therefore, we assume that this mixture forms a 2D
Fh lattice similar to that of pure 10, but with a nonuniform
Chem. Eur. J. 2003, 9, No. 4
¹ 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
0947-6539/03/0904-0931 $ 20.00+.50/0
931

V.Percec et al.
FULL PAPER
(HPLC); m.p. 98 998C (lit[17]: 99 1008C); 1H NMR (200 MHz, CDCl3,
208C, TMS): d ˆ 3.94 (s, 9H; CH3OPh), 7.52 ppm (s, 2H; ArH).
nanopatterning, membranes, nanoelectronics, and molecular-
recognition-based processes.In addition, the twin-dendritic
benzamide concept based on two identical tapered dendrons
can be extended to benzamides based on dissimilar tapered
and other dendritic shapes.Research along this line is in
progress in our laboratory.
3,4,5-Trihydroxy-1-nitrobenzene (3): Compound 2 (5 g, 23 mmol) was
mixed with pyridine hydrochloride (20 g).The mixture was stirred at 200 8C
for 40 min.The reaction mixture was extracted with EtOAc three times and
washed with dilute HCl, H2O, and finally with brine.The organic phase was
dried over anhydrous MgSO4 and evaporated to yield 2.75 g (69%) of 3 as
yellow crystals.The product was used for the next reaction without further
purification.Mp. .195 197 8C (194 1968C).[18]
:
3,4,5-Tris(4'-dodecyloxybenzyloxy)-1-nitrobenzene (5): Compound
3
Experimental Section
(2.75 g, 16 mmol), K2CO3, and DMF (100 mL) was added to a 500 mL
two-necked round bottomed flask, and N2 was bubbled through the
solution for 20 min.After the addition of 4 (15.3 g, 49 mmol), the reaction
mixture was stirred at 708C for 24 h under N2.The reaction mixture was
cooled to 208C and poured into an ice-water mixture.The crude product
was separated as a white solid, filtered, and dried under vacuum.The crude
product was passed through a short column of silica gel using Et2O as
eluent.The obtained product was purified by column chromatography
(EtOAc/hexanes 1:9) and recrystallized from acetone to obtain 11.4 g
(76%) of 5 as white crystals.Purity: 99% (HPLC); mp. .76 77 8C; Rf ˆ
Materials: 11-Bromoundecanoic acid (99%), methyl-4-hydroxybenzoate
(99%), 1,2,3-trimethoxybenzene (98%), methyl-3,4,5-trihydroxybenzoate
(98%), SOCl2 (99%), LiAlH4 (95%), pyridine (99%), graphite, Amber-
lite-120 (all from Aldrich), borane-THF complex (1.0m solution), 1-bro-
mododecan (98%), hydrazine hydrate (98%), triethyl orthoformate
(98%), catechol (99%), 3,4-dihydroxybenoic acid (97%), K2CO3 (99%),
MgSO4, DMF (Lancaster), HCl, H2SO4, HNO3, KOH; Na2SO4, NaHCO3
(Fisher), methacryloyl chloride (97%) (Acros), silica gel (Natland) were
used as received.The nitrating agent (25% HNO 3 on silica gel by titration
with 1N NaOH using phenolphthalein as an indicator) was prepared
according to a literature procedure,[16] and was used after drying in air for
seven days.Benzene (thiophene-free, Fisher) used for the free radical
polymerizations was washed three times with concentrated H2SO4 and
dried over MgSO4. 4'-Dodecyloxybenzyl chloride (4) and 4'-(11'-hydroxy-
undecyloxy)benzylchloride (12) were synthesized according to literature
procedures.[5n]
Techniques: 1H (200 MHz) NMR spectra were recorded on a Bruker AC-
200. 13C (90 MHz, 125 MHz) NMR spectra were recorded on a Bruker AC-
360 and Bruker DRX 500.Thin layer chromatography (TLC) was
performed on precoated TLC plates (silica gel with F254 indicator; layer
thickness, 200 mm; particle size, 5 ꢃ 25 mm; pore size, 60 ä, SIGMA-
Aldrich).Melting points were measured using a uni-melt capillary melting
point apparatus, (Thomas) and are uncorrected.
1
0.65 (hexanes/EtOAc 4:1); H NMR (200 MHz, CDCl3, 208C, TMS): d ˆ
0.88 (t, 3J(H,H) ˆ 6.4 Hz, 9H; CH3,), 1.27 (overlapped m, 54H; (CH2)9,
1.77 (m, 6H; CH2CH2OPh), 3.95 (m, 6H; CH2OPh), 5.06 (d, 3J(H,H) ˆ
2.4 Hz, 6H; PhCH2OPh), 6.75 (d, 2H; meta to CH2OPh, 4-position), 6.89
(d, 3J(H,H) ˆ 8.7 Hz, 4H; meta to CH2OPh, 3,5-position,), 7.20 7.34 (m,
6H; ortho to CH2OPh), 7.55 ppm (s, 2H; ortho to NO2); 13C NMR
(90 MHz, CDCl3, 208C, TMS): d ˆ 14.3, 22.9, 26.3, 29.7, 32.1, 68.2, 71.5, 75.1,
103.5, 114.6, 127.9 130.5, 143.0, 144.0, 152.7, 159.4 ppm; elemental analysis
calcd (%) for C63H95NO8 MW: C 76.08, H 9.62, N 1.40; found: C 75.93, H
9.58, N 1.46.
3,4,5-Tris(4'-dodecyloxybenzyloxy)-1-aminobenzene (6): Compound 5 (4 g,
4 mmol), NH2NH2 ¥ H2O (1 mL, 20 mmol), and graphite (3.5 g) were heated
in refluxing EtOH (50 mL) for 24 h under Ar.The reaction mixture was
cooled to 208C and was diluted with CH2Cl2 (50 mL).Graphite was filtered
and washed several times with CH2Cl2.The colorless organic phase was
concentrated and precipitated in MeOH .The solid was filtered and
recrystallization from acetone produced 3.18 g (82%) of 6 as white crystals.
Purity: 99% (HPLC); m.p. 84 868C; Rf ˆ 0.11 (hexanes/EtOAc 4:1);
1H NMR (200 MHz, CDCl3, 208C, TMS): d ˆ 0.88 (t, 3J(H,H) ˆ 6.4 Hz,
9H; CH3), 1.27 (overlapped m, 54H; (CH2)9, 1.76 (m, 6H; CH2CH2OPh),
3.94 (m, 6H; CH2OPh), 4.93 (d, 3J(H,H) ˆ 22.3 Hz, 6H; PhCH2OPh), 5.99
(s, 2H; ortho to NH2), 6.75 (d, 3J(H,H) ˆ 8.7 Hz, 2H; meta to CH2OPh,
4-position), 6.87 (d, 3J(H,H) ˆ 8.7 Hz, 4H; meta to CH2OPh, 3,5-position),
7.28 ppm (m, 6H; ortho to CH2OPh); 13C NMR (90 MHz, CDCl3, 208C,
TMS): d ˆ 14.3, 22.9, 26.3, 29.7, 32.1, 68.2, 71.2, 75.2, 96.0, 114.4, 129.2
131.5, 142.6, 153.7, 159.0 ppm; elemental analysis calcd (%) for C63H97NO6:
C 78.45, H 10.13, N 1.45; found: C 78.20, H 10.47, N 1.41.
GPC analysis was performed on a Shimadzu LC-10AT high pressure liquid
chromatograph equipped with CTO-10A column oven (408C), a PE Nelson
Analytical 900 Series integrator data station, Shimadzu RID-10A RI
detector, SPD-10A UV-Vis detector (254 nm), and two columns AM gel
(10 mm, 500 ä and 10 mm, 104 ä).THF (Fisher HPLC grade) was used as
eluent at a flow rate of 1 mLminÀ1.Number and weight average molecular
weights were determined using calibration plots constructed with poly-
styrene standards.
Thermal transitions were measured on a Perkin Elmer DSC-7 differential
scanning calorimeter (DSC).In all cases, the heating and the cooling rates
were 108CminÀ1.The transition temperatures were reported as the maxima
and minima of their endothermic and exothermic peaks.Indium was used
as calibration standard.An Olympus BX-40 optical polarized microscope
(100 Â magnification) equipped with a Mettler FP 82 hot stage and a
Mettler FP 80 central processor was used to verify thermal transitions and
characterize anisotropic textures.
Methyl 3,4,5-Tris(4'-dodecyloxybenzyloxy)benzoate (8): Compound 8 was
synthesized by using a similar procedure as the one used for the synthesis of
5.Starting from compounds 7 (1.55 g, 8.4 mmol), 4 (7.86 g, 25.3 mmol), and
K2CO3 (7 g, 50.7 mmol) in DMF (50 mL), 7.65 g (90%) of 8 was obtained as
white crystals after recrystallization from acetone.Purity: 99% (HPLC);
m.p. 67 688C; Rf ˆ 0.78 (hexanes/EtOAc 4:1); 1H NMR (200 MHz,
CDCl3, 208C, TMS): d ˆ 0.89 (t, 3J(H,H) ˆ 6.1 Hz, 9H; CH3), 1.27 (over-
lapped m, 54H; (CH2)9), 1.79 (m, 6H; CH2CH2OPh), 3.89 3.97 (over-
lapped m, 9H; CH2OPh, CO2Me), 5.05 (d, 3J(H,H) ˆ 7.6 Hz, 6H;
PhCH2OPh), 6.75 (d, 3J(H,H) ˆ 8.4 Hz, 2H; meta to CH2OPh, 4-position),
6.89 (d, 3J(H,H) ˆ 8.4 Hz, 4H; meta to CH2OPh, 3,5-position), 7.23
7.36 ppm, (m, 8H; ortho to CH2OPh, ortho to CO2Me); 13C NMR
(90 MHz, CDCl3, 208C, TMS): d ˆ 14.3, 22.9, 26.3, 29.7, 32.1, 52.4, 68.2,
71.2, 74.9, 109.3, 114.6, 125.2, 128.7 130.5, 142.6, 152.8, 159.2, 166.9 ppm.
X-ray diffraction measurements were carried out with CuKa radiation from
a Bruker-Nonius FR-591 rotating anode X-ray source with a 0.2 Â 2.0 mm2
filament operated at 3.4 kW. The beam was collimated and focused by a
single bent mirror and sagitally focusing Ge(111) monochromator, result-
ing in a 0.2 Â 0.2 mm2 spot on a multiwire detector 125 cm from the sample.
To minimize attenuation and background scattering, an integral vacuum
was maintained along the length of the flight tube and within the sample
chamber.The samples were held in a temperature-controlled ( Æ0.18C)
oven.Densities ( 120) were determined by flotation in gradient columns at
208C.Elemental analyses of all new compounds (M-H-W Laboratories,
Phoenix, AZ) agree with the calculated value within Æ 0.4%.
3,4,5-Tris(4'-dodecyloxybenzyloxy)benzoic acid (9): Compound 8 (7.5 g,
7.5 mmol), EtOH (80 mL), and KOH solution (1 g dissolved in 10 mL H2O)
was placed into a 200 mL round flask containing a Teflon coated magnetic
stirring bar.The mixture was refluxed for 2 h under constant stirring.The
extent of reaction was followed by TLC.After the reaction was complete,
the reaction mixture was cooled to 208C.The reaction mixture was diluted
with THF (100 mL), and was acidified with dilute HCl to pH 1 at 08C.The
reaction mixture was poured into an ice–water mixture.The precipitated
white solid was collected by filtration and dried.Recrystallization of the
3,4,5-Trimethoxy-1-nitrobenzene (2): Compound (1) (40 g, 0.238 mol) in
CH2Cl2 (100 mL) was added rapidly to a stirred suspension of SiO2 ¥ HNO3
(132 g, 0.354 mol) in CH2Cl2 (400 mL) at 208C.The resulting red solution
was stirred at 208C for 15 min.SiO 2 was filtered and washed several times
with CH2Cl2.The organic phases were combined, concentrated, and
precipitated in MeOH.The yellow crude product was filtered and extracted
with hot MeOH.Purification by column chromatography (SiO 2, EtOAc/
hexane 1:4) produced 16.5 g (33%) of 2 as yellow crystals.Purity: 99%
932
¹ 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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Chem. Eur. J. 2003, 9, No. 4

Liquid Crystalline Lattices and Superlattices
921 935
crude product from acetone produced 7.10 g (96%) of 9 as white crystals.
Purity: 99% (HPLC); m.p. 142 1438C; 1H NMR (200 MHz, CDCl3, 208C,
TMS): d ˆ 0.88 (t, J(H,H) ˆ 6.4 Hz, 9H; CH3), 1.27 (overlapped m, 54H;
reaction was followed by TLC.After the reaction was completed, the
temperature of the reaction mixture was cooled to 208C.The silica gel was
filtered and rinsed with MeOH and CH2Cl2.The solvent was evaporated
and the solids were precipitated in H2O from MeOH, and dried in air to
obtain 14 (2.55 g, 91%) as a light yellow solid, which was used in the next
step without further purification. Rf ˆ 0 (hexanes/EtOAc 7:3); m.p. 105
3
(CH2)9), 1.79 (m, 6H; CH2CH2OPh), 3.95 (m, 6H; CH2OPh), 5.05 (d,
3J(H,H) ˆ 5.3 Hz, 6H; PhCH2OPh), 6.75 (d, 3J(H,H) ˆ 8.6 Hz, 2H; meta to
CH2OPh, 4-position), 6.90 (d, 3J(H,H) ˆ 8.6 Hz, 4H; meta to CH2OPh, 3,5-
position), 7.23 7.36 (m, 6H; ortho to CH2OPh), 7.42 ppm (s, 2H; ortho to
CO2H); 13C NMR (90 MHz, CDCl3, 208C, TMS): d ˆ 14.3, 22.9, 26.3, 29.7,
32.1, 68.2, 71.3, 74.9, 109.9, 114.5, 124.2, 128.6 130.5, 143.4, 152.9, 159.2,
171.8 ppm.
1
1088C; H NMR (200 MHz, CDCl3, 208C, TMS): d ˆ 1.30 (overlapped m,
16H; (CH2)8), 1.77 (m, 2H; CH2CH2OPh), 3.65 (t, 2H; CH2OH), 3.88 (s,
3H; CO2Me), 3.97 (t, 2H; CH2OPh), 5.04 (s, 2H; PhCH2OPh), 6.92 ppm
(d, 2H; meta to CH2OPh), 7.25 7.36 ppm (overlapped m, 4H; ortho to
CH2OPh, ortho to CO2Me); 13C NMR (125 MHz, CDCl3 and a few drops of
DMSO, 208C, TMS): d ˆ 25.7 25.9 (m), 29 29.4 (m), 32.7, 51.7, 62.4, 68,
71, 106.8, 111.1., 114.4, 120.7, 128.2, 129.6, 138.8, 144.7, 146.3, 159,
166.7 ppm; elemental analysis calcd (%) for C26H36O7: C 67.79, H 7.87;
found: C 68.01, H 7.95.
N-[3,4,5-Tris(4'-dodecyloxybenzyloxy)phenyl]-3,4,5-tris(4'-dodecyloxy-
benzyloxy)benzamide (10): Compound
9 (1.0 g, 1.0 mmol), 6 (0.97 g,
1.0 mmol), DCC (624 mg, 3.0 mmol), DPTS (89 mg, 0.3 mmol), and dry
CH2Cl2 (20 mL) under N2 were placed in a 50 mL three-necked round
bottomed flask containing a Teflon coated magnetic stirring bar.The
reaction mixture was stirred at 208C for 24 h.The extent of the reaction was
followed by TLC.After the reaction was completed, the reaction mixture
was precipitated in MeOH.The solid was collected by filtration and dried
in air.Purification of the crude product by column chromatography
(EtOAc/hexanes 1:9), and recrystallization from acetone produced 1.69 g
(87%) white crystals of 10.Purity: 99% (HPLC); Rf ˆ 0.94 (hexanes/
EtOAc 4:1); 1H NMR (200 MHz, CDCl3, 208C, TMS): d ˆ 0.88 (t,
3J(H,H) ˆ 6.4 Hz, 18H; CH3), 1.26 (overlapped m, 108H; (CH2)9), 1.78
(m, 12H; CH2CH2OPh), 3.94 (m, 12H; CH2OPh), 5.0 (d, 3J(H,H) ˆ
17.6 Hz, 12H; PhCH2OPh), 6.76 (d, 3J(H,H) ˆ 8.6 Hz, 4H; meta to
CH2OPh, 4-position), 6.88 (d, 3J(H,H) ˆ 8.5 Hz, 8H; meta to CH2OPh,
3.5-position), 6.98 (s, 2H; ortho to NHCO), 7.08 (s, 2H; ortho to CONH),
7.24 7.35 (m, 12H; ortho to CH2OPh), 7.57 ppm (s, 1H; CONH); 13C NMR
(90 MHz, CDCl3, 208C, TMS): d ˆ 14.3, 22.9, 26.3, 29.7, 32.1, 68.2, 71.3, 75.0,
100.3, 107.1, 114.4, 128.6 130.5, 134.0,135.3,141.7, 153.2, 159.2, 165.6 ppm;
elemental analysis calcd (%) for C127H191NO13 (MW): C 78.62, H 9.92;
found: C 78.43, H 10.20.
Methyl 3,4-bis(4'-dodecyloxybenzyloxy)-5-[4'-(11'-hydroxyundecyloxy)-
benzyloxy]benzoate (15): Compound 15 was synthesized by the same
general procedure as the one used for the synthesis of compound 5.The
reagents used were 14 (2.55 g, 5.5 mmol), 4 (3.51 g, 11 mmol), and K2CO3
(4.70 g, 34 mmol) in DMF (20 mL). Compound 15 (4.41 g, 79%) was
obtained as white crystals after recrystallization from acetone twice.Purity:
99% (HPLC); m.p. 70 718C; Rf ˆ 0.12 (hexanes/EtOAc 4:1); 1H NMR
(200 MHz, CDCl3, 208C, TMS): d ˆ 0.88 (t, 3J(H,H) ˆ 6.4 Hz, 6H; CH3),
1.27 (overlapped m, 52H; (CH2)x), 1.76 (m, 6H; CH2CH2OPh), 3.63 (t,
3J(H,H) ˆ 5.9 Hz, 2H; CH2OH), 3.89 4.00 (overlapped m, 9H; CH2OPh,
CO2Me), 5.03 (d, 3J(H,H) ˆ 6.9 Hz, 6H; PhCH2OPh), 6.74 (d, 3J(H,H) ˆ
6.7 Hz, 2H; meta to CH2OPh, 4 position), 6.89 3J(H,H) ˆ 6.6 Hz, 4H; meta
to CH2OPh, 3,5 position), 7.23 7.35 ppm (m, 8H; ortho to CH2OPh, ortho
to CO2Me); 13C NMR (90 MHz, CDCl3, 208C, TMS): d ˆ 14.3, 22.9, 25.9
26.3 (m), 29.7, 32.1, 33.0, 52.4, 63.3, 68.2, 71.3, 74.9, 109.3, 114.5, 125.2,
128.7 130.5, 142.4, 152.8, 159.2, 166.9 ppm; elemental analysis calcd (%)
for C29H40O8: C 67.41, H 7.80; found: C 67.64, H 7.63.
2-Ethoxy-7-hydroxy-benzo[1,3]dioxole-5-carboxylic acid methyl ester (11):
Compound 7 (50 g, 0.27 mol), triethyl orthoformate (150 mL) and a few
grains of Amberline-120 resin under N2 were added to a 250 mL three-
necked round bottomed flask containing a Teflon coated magnetic stirring
bar.The reaction mixture was heated at 130 8C for 18 h, cooled to 208C, and
then diluted with 250 mL of CHCl3.The grains of Amberline-120 were
removed from the reaction mixture by filtration.The organic phase was
collected, washed with saturated NaHCO3 solution, H2O and brine, and
dried over anhydrous Na2SO4.The solvent was evaporated and the white
solid was precipitated in hexane from CH2Cl2 solution.The crude product
was purified by recrystallization from CHCl3/hexanes to produce 37 g
(57%) of 11 as white crystals. Rf ˆ 0.4 (hexanes/EtOAc 7:3); 11 decom-
poses before melting; 1H NMR (200 MHz, CDCl3, 208C, TMS): d ˆ 1.27 (t,
3J(H,H) ˆ 7.1 Hz, 3 H ; CH 3), 3.75 (q, 3J(H,H) ˆ 7.1 Hz, 2H; CH2O), 3.89 (s,
3H; CO2Me), 5.82 (s, 1H; OH), 6.95 (s, 1H; CH(OR)3, 7.18 (d, 3J(H,H) ˆ
1.6 Hz, 1H; ortho to OH), 7.41 ppm (d, 3J(H,H) ˆ 1.5 Hz, 1H; para to OH);
13C NMR (125 MHz, CDCl3 and a few drops of DMSO, 208C, TMS): d ˆ
14.8, 51.7, 52, 59.3, 101.6, 109.5, 114, 119.6, 137.2, 144.8, 167 ppm; elemental
analysis calcd (%) for C11H12O6: C 54.98, H 5.03; found: C 55.24, H 5.20.
3,4-Bis(4'-dodecyloxybenzyloxy)-5-[4'-(11'-hydroxyundecyloxy)benzyloxy]
benzoic acid (16): Compound 16 was synthesized by the same general
procedure as the one described for the synthesis of 9, from compouund 15
(3.8 g) in EtOH (50 mL), 3.42 g (91%) of 16 was obtained as white crystals
after recrystallization from acetone.Purity: 99% (HPLC).mp. .85 86 8C;
Rf ˆ 0.1 (hexanes/EtOAc 4:1); 1H NMR (200 MHz, CDCl3, 208C, TMS):
d ˆ 0.88 (t, 3J(H,H) ˆ 6.1 Hz, 6H; CH3), 1.26 (overlapped m, 52H; (CH2)x),
3
1.77 (m, 6H; CH2CH2OPh), 3.63 (t, J(H,H) ˆ 6.5 Hz, 2H; CH2OH), 3.93
(m, 6H; CH2OPh), 5.00 (d, 3J(H,H) ˆ 4.8 Hz, 6H; PhCH2OPh), 6.73 (d,
3J(H,H) ˆ 8.3 Hz, 2H; meta to CH2OPh,
4 position), 6.86 ppm (d,
3J(H,H) ˆ 8.3 Hz, 4H; meta to CH2OPh, 3,5 position), 7.21 7.40 ppm
(overlapped m, 8H; ortho to CH2OPh, ortho to CO2H); 13C NMR
(90 MHz, CDCl3, 208C, TMS): d ˆ 14.3, 22.9, 25.9 26.3 (m), 29.7, 32.1,
32.9, 63.3, 68.2, 71.2, 74.9, 109.3, 114.5, 124.3, 128.6 130.5 (m), 143.3, 152.8,
159.2, 171.2 ppm
3,4-Bis(4'-dodecyloxybenzyloxy)-5-[4'-(11'-methacryloxyundecyloxy)ben-
zyloxy]benzoic acid (18): Compound 16 (3.2 g, 3.22 mmol), dry Et3N
(1.40 mL, 10 mmol), and dry CH2Cl2 (20 mL) were added under N2 to a
100 mL flask.Methacryloyl chloride (1 g, 9.6 mmol) was added drop wise at
08C, and the reaction was stirred at 208C overnight.The reaction mixture
was concentrated and precipitated in MeOH.After filtration, the light
yellow solids were dissolved in pyridine (30 mL) and H2O (4 mL).The
mixture was heated to 1308C for 2 h to cleave the mixed ester anhydride 17.
After acidification with dilute HCl at 08C, the reaction mixture was
extracted with Et2O.The organic layer was washed with NaHCO 3 solution
(5%) and dried over anhydrous MgSO4.The solvent was evaporated, and
the crude product was purified by column chromatography (SiO2, hexanes/
EtOAc 4:1) to yield 18 (2.56 g, 75%) as white crystals after recrystallization
from acetone.Purity: 99% (HPLC); Rf ˆ 0.2 (hexanes/EtOAc 4:1);
1H NMR (200 MHz, CDCl3, 208C, TMS): d ˆ 0.88 (t, 3J(H,H) ˆ 6.4 Hz,
6H; CH3), 1.27 (overlapped m, 50H; (CH2)x), 1.75 (m, 8H; CH2CH2OPh,
CH2CH2OCOR), 1.94 (m, 3H; CH3C ˆ CH2), 3.94 (m, 6H; CH2OPh), 4.14
(t, 3J(H,H) ˆ 6.6 Hz, 2H; CH2OCOR), 5.04 (d, 3J(H,H) ˆ 5.0 Hz, 6H;
PhCH2OPh), 5.54 (m, 1H; H2C ˆ CR2, trans), 6.09 (m, 1H; H2C ˆ CR2,
cis), 6.75 (d, 3J(H,H) ˆ 8.5 Hz, 2H; meta to CH2OPh, 4-position), 6.89 ppm
(d, 3J(H,H) ˆ 8.7 Hz, 4H; meta to CH2OPh, 3,5-position), 7.23 7.42 ppm
(overlapped m, 8H; ortho to CH2OPh, ortho to CO2H); 13C NMR
(90 MHz, CDCl3, 208C, TMS): d ˆ 14.3, 18.5, 22.9, 26.2, 29.6, 32.1, 65.1,
68.2, 71.2, 74.9, 109.9, 114.5, 124.2, 125.4, 128.6 130.5 (m), 136.7, 143.4,
2-Ethoxy-7-[4'-(11'-hydroxyundecyloxy)benzyloxy]benzo[1,3]dioxole-5-
carboxylic acid methyl ester (13): Compound 13 was synthesized by using a
similar procedure as the one used for the synthesis of 5.The reagents used
were 11 (3.06 g, 13 mmol), 12 (4.18 g, 13 mmol),and K2CO3 (5.18 g,
37 mmol) in DMF (45 mL).Compound 13 (4.73 g, 72%) was obtained as
white crystals after recrystallization from acetone.Purity: (HPLC), 99%.
m.p. 59 608C; Rf ˆ 0.33 (hexanes/EtOAc 7:3); 1H NMR (200 MHz,
CDCl3, 208C, TMS): d ˆ 1.31 (overlapped m, 19H; (CH2)8, CH3), 1.77
(m, 2H; CH2CH2OPh), 3.62 3.75 (m, 4H; CH2OH; CH3CH2O), 3.89 3.99
(m, 5H; CH2OPh, CO2Me), 5.15 ppm(s, 2H; PhCH2OPh), 6.88 6.96 (m,
3H; meta to CH2OPh, CH(OR)3), 7.25 7.44 ppm (overlapped m, 4H;
ortho to CH2OPh, ortho to CO2Me); 13C NMR (125 MHz, CDCl3, 208C,
TMS): d ˆ 25.9 26.2 (m), 29.4 29.8 (m), 33, 52.2, 63.3, 68.2, 71.5, 97.8,
104.1, 111.9, 114.7, 120, 123.6, 128.5, 129.7, 148.6, 159.4, 166.8 ppm;
elemental analysis calcd (%) for C29H40O8: C 67.41, H 7.80; found: C
67.64, H 7.63.
Methyl 3,4-dihydroxy-5-[4'-(11'-hydroxy-undecyloxy)benzyloxy]benzoate
(14):Compound 13 (3.15 g), silica gel (18 g), and MeOH (80 mL) were
placed into a 200 mL round-bottomed flask containing a Teflon coated
magnetic stir bar.The mixture was refluxed for 20 h.The progress of the
Chem. Eur. J. 2003, 9, No. 4
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V.Percec et al.
FULL PAPER
152.8, 159.2, 167.8, 171.7 ppm; elemental analysis calcd (%) for C67H98O10s
C 76.14, H 9.58; found: C 75.98, H 9.43.
:
[4] a) V.Percec, G.Johansson, J.Heck, G.Ungar, S.V.Batty,
J. Chem.
Soc. Perkin Trans. 1 1993, 1411; b) G.Johansson, V.Percec, G.Ungar,
D.Abramic, J. Chem. Soc. Perkin Trans. 1 1994, 447; c) G.Ungar, S.V.
N-[3,4,5-Tris(4'-dodecyloxybenzyloxy)phenyl]-3,4-bis(4'-dodecyloxyben-
Batty, V.Percec, J.Heck, G.Johansson,
Adv. Mater. Opt. Electron.
zyloxy)-5-[4'-(11'-methacryloxyundecyloxy)benzyloxy]benzamide
(19):
1994, 4, 303; d) D.Tomazos, G.Out, J.Heck, G.Johansson, V.Percec,
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1997, 119, 1539; g) S.D.Hudson, H.T.Jung, V.Percec, W.D.Cho, G.
Compound 19 was synthesized by the same procedure as the one described
for the synthesis of compound 10.Starting from 18 (1.25 g, 1.18 mmol), 6
(1.13 g, 1.18 mmol), DCC (485.7mg, 2.35 mmol), and DPTS (69.2 mg,
0.24 mmol) in dry THF (20 ml), 19 (1.65 g, 70%) was obtained as white
crystals after purification by column chromatography (SiO2, hexanes/
EtOAc 9:1), and recrystallization from acetone.Purity: 99% (HPLC);
Johansson, G.Ungar, V.S.K.Balagurusamy,
Science 1997, 278, 449;
1
h) V.Percec, W.D.Cho, P.E.Mosier, G.Ungar, D.J.P.Yeardley,
J.
Rf ˆ 0.72 (hexanes/EtOAc 4:1); H NMR (200 MHz, CDCl3, 208C, TMS):
d ˆ 0.88 (t, 3J(H,H) ˆ 6.3 Hz, 15H; CH3), 1.26 (overlapped m, 104H;
(CH2)9), 1.74 (m, 14H; CH2CH2OPh, CH2CH2OCOR), 1.94 (s, 3H;
CH3C ˆ CH2), 3.94 (m, 12H; CH2OPh), 4.13 (t, 3J(H,H) ˆ 6.6 Hz, 2H;
CH2OCOR), 5.02 (m, 12H; PhCH2OPh), 5.54 (s, 1H; H2C ˆ CR2, trans),
6.09 (s, 1H; H2C ˆ CR2, cis), 6.76 (d, 3J(H,H) ˆ 8.1 Hz, 4H; meta to
CH2OPh, 4 position), 6.88 (d, 3J(H,H) ˆ 8.1 Hz, 8H; meta to CH2OPh, 3,5
position), 6.99 (s, 2H; ortho to NHCO), 7.09 (s, 2H; ortho to CONH), 7.24
7.35 (overlapped m, 12H; ortho to CH2OPh), 7.51 ppm (s, 1H; CONH);
13C NMR (90 MHz, CDCl3, 208C, TMS): d ˆ 14.3, 18.5, 22.9, 26.2, 29.7, 32.0,
65.0, 68.2, 71.3, 75.0, 100.3, 107.1, 114.5, 125.4, 128.6 130.5 (m), 134.1,135.3,
136.7, 141.7, 153.2, 159.2, 165.7, 167.8 ppm; elemental analysis calcd (%) for
C130H193O15N: C 77.67, H 9.67; found: C 77.51, H 9.80.
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Polymerization of 19: Monomer 19 was polymerized as 50% (w/v) solution
in benzene under argon at 608C for 18 h.AIBN (1% w/w) was used as
radical initiator.The polymerization solution was degassed by three freeze-
pump-thaw cycles before the polymerization was initiated.Polymer 20 was
then separated from unreacted monomer by column chromatography
(neutral alumina, hexanes).Finally, the purified polymer 20 was dissolved
in CH2Cl2 and precipitated in cold methanol to yield 20 (0.95 g, 79%) as a
light yellow solid; Mn ˆ 49813 and Mw/Mn ˆ 1.62 (GPC with polystyrene
standards).
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mixture of 20 with 10 (20/10 (x:y)) was prepared by weighing the individual
components in a glass vial and then adding dry THF to give an equal final
volume of a homogeneous solution.Solvent was removed under a gentle
stream of dry N2 and the mixture was dried under vacuum for 12 h at 208C.
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Acknowledgement
Ungar, V.Percec, M.N.Holerca, G.Johansson,
J. Am. Chem. Soc.
2000, 122, 1684; k) H.Duan, S.D.Hudson, G.Ungar, M.N.Holerca,
V.Percec, Chem. Eur. J. 2001, 7, 4134; l) V.Percec, M.N.Holerca, S.
Uchida, S.N.Magonov, D.J.P.Yeardley, G.Ungar, H.Duan, S.D.
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Financial support by ONR and the National Science Foundation (DMR-
9996288 and DMR-0102459) is gratefully acknowledged.We are also
grateful to Professor S.Z.D.Cheng of the University of Akron for density
measurements.
Holerca, S.Uchida, D.J.P.Yeardley, G.Ungar,
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