Self-assembly of hybrid dendrons with complex primary structure into functional helical pores

Article abstract of DOI:10.1002/chem.200601582

The synthesis of three libraries of self-assembling hybrid dendrons containing a primary structure based on the sequence (4-3,4-3,5)12G2-CO ₂CH₃ generated from benzyl ether, biphenyl-4-methyl ether, and AB₂ repeat units co

Full text of DOI:10.1002/chem.200601582

FULL PAPER
DOI: 10.1002/chem.200601582
Self-Assembly of Hybrid Dendrons with Complex Primary Structure Into
Functional Helical Pores
Virgil Percec,*[a] Jan Smidrkal,[a] Mihai Peterca,[a, b] Catherine M. Mitchell,[a]
Sami Nummelin,[a] AndrØs E. Dulcey,[a] Monika J. Sienkowska,[a] and Paul A. Heiney[b]
Abstract: The synthesis of three libra-
ries of self-assembling hybrid dendrons
containing a primary structure based
on the sequence (4-3,4-3,5)12G2-
CO2CH3 generated from benzyl ether,
biphenyl-4-methyl ether, and AB2
pores. The self-assembly of an example
of hybrid dendron containing -H,
strategy for the design and synthesis of
porous columns containing a diversity
of hydrophilic and hydrophobic func-
tional groups in the inner part of the
pore. The results reported here expand
the scope and limitations of dendrons
available for the self-assembly of func-
tional pores that previously were gen-
erated mostly from dendritic dipepti-
des, to simpler architectures based on
hybrid dendrons.
-CO2CH3,
-COOK, -CONH2, -CONHCH3, -CO2-
(CH2)2OCH3, -(R) and -(S)-CONHCH-
(CH3)C2H5 as X-groups at the apex
-CH2OH,
-COOH,
AHCTREUNG
AHCTREUNG
ꢀ
repeat units constructed from (AB)y
demonstrated that these self-assem-
bling dendrons provide the simplest
AB2 combinations of benzyl ethers, is
reported. The structural and retrostruc-
tural analysis of their supramolecular
dendrimers facilitated the discovery of
new architectural principles that lead
to the assembly of functional helical
Keywords: functional
pores
·
helical chirality · hybrid dendrons ·
liquid crystals · self-assembly
Introduction
classes of self-assembling dendrons, we have discovered sev-
eral examples of dendrons without a dipeptide at their apex
that self-assemble into helical pores.[3a,e,4a,b] Of particular in-
terest were nonfunctionalized hybrid dendrons with a pri-
Natural porous proteins function as viral helical coats,[1a,b]
transmembrane channels,[1c,d] antibiotics,[1e] patogens,[1f] and
mediate protein folding.[1g] Their remodeled structures are
used for reversible encapsulation[1h] and for stochastic sen-
sing.[1i] Various strategies to mimic the structure and func-
tions of natural porous proteins have been elaborated.[2]
Our laboratory reported a general strategy for the design,
synthesis, and self-assembly of helical pores from dendritic
dipeptides.[3] During investigations on the principles, the
scope, and the limitations of self-assembly of helical pores
from dendritic dipeptides, and on the development of new
ꢀ
mary structure based on combinations of (AB)y AB3 and
[3a,4c]
ꢀ
(AB)y AB2 benzyl ether building blocks
that resemble
AB3 and AB2 biphenyl-4-methyl ether[4b,8] dendritic repeat
units. Both hybrid benzyl ether[4c] and biphenyl-4-methyl
ether[4b,8] based dendrons provided several examples of
porous assemblies.[3a,5a] Therefore, we decided to search for
potential helical-pore-forming dendrons with various archi-
tectures incorporated in the (4-3,4-3,5)12G2-X primary
structure that was employed in the design of dendritic di-
peptides.[3] The supramolecular column self-assembled from
the sequence (4-3,4-3,5)12G2-X generated from benzyl
ether repeat units with X=CH2OH and CO2CH3 does not
exhibit a hollow center.[3e] However, the same building
blocks based on biphenylmethyl ether repeat units self-as-
semble both into porous columns and in spheres.[4b] Conse-
quently, we decided to investigate even more complex archi-
tectures generated from hybrid dendrons based on the same
sequence of the primary structure and compositions that
[a] Prof. V. Percec, J. Smidrkal, Dr. M. Peterca, Dr. C. M. Mitchell,
S. Nummelin, Dr. A. E. Dulcey, Dr. M. J. Sienkowska
Roy & Diana Vagelos Laboratories
Department of Chemistry
Laboratory for Research on the Structure of Matter
University of Pennsylvania, Philadelphia, PA 19104-6323 (USA)
Fax : (+1)215-573-7888
E-mail: percec@sas.upenn.edu
[b] Dr. M. Peterca, Prof. P. A. Heiney
ꢀ
consist of repeat units generated from: (AB)y AB2 combi-
Department of Physics and Astronomy
Laboratory for Research on the Structure of Matter
University of Pennsylvania, Philadelphia, PA 19104-6396 (USA)
nations of 4- and 3,4-benzyl ethers as AB2 units,[4d] 4’-, 3’,4’-
and 3’,5’-biphenyl-4-methyl ethers as AB and AB2 units,[4b]
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and 4-benzyl ether as AB and 3,4-and 3,5-benzyl ethers as
AB2 repeat units. The 3,4,5-benzyl and 3’,4’,5’-biphenyl-4-
methyl ether structures were excluded from this study, since
these architectural motifs provide mostly dendrons that self-
assemble in spherical assemblies.[5] The results of this study
are reported here and are rewarding. These complex hybrid
dendrons based on (4-3,4-3,5)12G2-X primary structure
demonstrated a second general architectural motif, in addi-
tion to the dendritic dipeptides with the same primary se-
quence, that self-assemble into helical pores with pore diam-
eter and functionality that are complementary to those ac-
cessible from the dendritic dipeptide[3] building blocks.
The synthesis of the first library of hybrid dendrons based
on 4’-, 3’,4’-, and 3’,5’-biphenylmethyl ether and 4-, 3,4-, and
3,5-benzyl ether repeat units is outlined in Schemes 1 and 2.
Etherification of 2[4b] with 1[4d] in DMF at 908C (20 h), in
the presence of K2CO3 produced 3 in 76% yield. The first-
generation hybrid dendron 6 was obtained in 89% yield by
the etherification of 4[4b] with 5[4d] in DMF at 908C (15 h)
under Ar. Reduction of 6 with LiAlH4 in THF produced 7
(84% yield). Chlorination of 7 with SOCl2 in CH2Cl2 at
258C (3h) in the presence of 2,6-di- tert-butyl-4-methylpyri-
dine (DTBMP) proton trap[10] afforded 8 (74% yield).
The second-generation hybrid dendron 10 (74% yield)
was prepared by the etherification of 9[4d] with 8 in DMF at
908C (15 h) under Ar.
Results and Discussion
The second-generation dendron 16 was synthesized by fol-
lowing a similar sequence of reactions as the one described
above. Thus, etherification of 11 with 12 in DMF at 908C for
15 h under Ar produced 13 in 91% yield. Reduction of 13
with LiAlH4 in THF yielded alcohol 14 (93%), which was
chlorinated with SOCl2 in CH2Cl2 at 258C (2 h) in the pres-
ence DTBMP to produce 15 in 42% yield. Etherification of
9 with 15 in DMF at 908C (20 h) afforded the second-gener-
Synthesis of the self-assembling hybrid dendrons: The syn-
thesis of the self-assembling dendrons, and the structural
and the retrostructural analysis of their supramolecular as-
semblies were performed according to methods elaborated
in our laboratory.[3,4] The short nomenclature of the den-
drons is similar to that used in previous publications.[4b–d]
Scheme 1. Synthesis of hybrid dendrons based on 4-, 3,4, and 3,5-benzyl ether and 4’-, 3’,4’- and 3’-5’-biphenyl-4-methyl ether repeat units. Conditions:
i) K2CO3, DMF, 70–908C; ii) LiAlH4, THF; iii) SOCl2, DTBMP, CH2Cl2.
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Dendrimers
FULL PAPER
ation hybrid dendron 16 in 37% yield. The first-generation
13 and 14 and the second-generation 16 were isolated as
pure products after recrystallization from acetone.
the presence of K2CO3 afforded the second-generation den-
drons 23, 25, 27, 29 in 76, 68, 61, and 84% yields, respective-
ly.
The synthesis of the second library of hybrid dendrons
based on 4’-, 3’,4’-, and 3’,5’-biphenyl-4-methyl ether and 4-,
3,4-, and 3,5-benzyl ether repeat units is described in
Scheme 2. Etherification of 2 with 8 and with 15 in DMF at
908C under Ar in the presence of K2CO3 afforded 17 and 18
in 69 and 72% yields, respectively. Similarly, 20 (62% yield)
was prepared by the etherification of 9 with 19.
The last hybrid dendron of this series, which bears a hy-
drogen atom at the apex, was obtained by etherification of
3,5-dimethoxybiphenyl (21) with 28 under usual conditions
to produce 30 (70% yield). All second-generation dendrons
from Scheme 3were purified by column chromatography.
Synthesis of self-assembling hybrid dendrons with functional
groups athte apex : Scheme 4 shows the synthesis of eight
additional dendrons based on (4-3,4-4-3,5Bp)12G2-X (29,
30; Scheme 3). They contain a diversity of functional groups
at their apex: X=H, CH2OH, COOK, COOH, CO2-
ꢀ
The synthesis of the library containing five (AB)y AB2
hybrid dendrons based on 4-benzyl ether as AB and 3,4-
benzyl ether as well as 3’,4’- and 3’,5’-biphenyl-4-methyl
ether as AB2 repeat units is outlined in Scheme 3. Etherifi-
cation of 2 with 22, 24, 26, 28 in DMF at 908C under Ar in
A
CONH2,
CONHCH3,
(CH3)C2H5,
(S)-CONHCH-
(R)-CONHCH-
AHCTREUNG
AHCTREUNG
CH2OH (31) in 90% yield.
Saponification of the ester 29
in THF/H2O mixture with
KOH produced the potassium
salt
(4-3,4-4-3,5Bp)12G2-
COOK (32) in quantitative
yield. The salt 32 was acidified
with acetic acid to generate
the corresponding acid (4-3,4-
4-3,5Bp)12G2-COOH (33) in
80% yield after recrystalliza-
tion from acetone. Esterifica-
tion of 32 with 2-methoxyetha-
nol by using N,N’-dicyclohexyl-
carbodiimide (DCC) as an ac-
tivating agent and 4-(dimethyl-
amino)pyridinium-4-toluene-
sulfonate (DPTS) as catalyst
provided
ester
(4-3,4-4-
3,5Bp)12G2-CO
AHCTREUNG
(34) in 87% yield. Chlorina-
tion of 32 with SOCl2 in
CH2Cl2 at 258C (2 h) in the
presence of a DTBMP proton
trap, followed by the reaction
with NH3 produced the amide
(4-3,4-4-3,5Bp)12G2-CONH2
(35) in 61% yield. Both 34 and
35 were purified by column
chromatography with CH2Cl2/
MeOH (25:1 and 15:1 ratio,
respectively) mixture as eluent
followed by recrystallization
from acetone. The amide (4-
3,4-4-3,5Bp)12G2-CONHCH3
(36) was synthesized in 62%
yield by the reaction of 32
with methylammonium chlo-
Scheme 2. Synthesis of hybrid dendrons based on 4-, 3,4- and 3,5-benzyl ether and 4’-, 3’,4’- and 3’,5’-biphenyl-
4-methyl ether repeat units. Conditions: i) K2CO3, DMF, 70–908C.
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V. Percec et al.
Scheme 3. Synthesis of (AB)y-AB2 hybrid dendrons based on 4-benzyl ether as AB repeat unit and 3,4-benzyl ether and 3’,5’-biphenyl-4-methyl ether as
AB2 repeat units.
ride in the presence of carbon-
yl diimidazoline (CDI), DPTS,
and NEt3. Pure 36 was ob-
tained by recrystallization
from acetone. Chlorination of
32 with SOCl2 in CH2Cl2 at
258C in the presence of
DTBMP, followed by the ami-
nation with (S)-sec-butylamine
or (R)-sec-butylamine afforded
(S)-(4-3,4-4-3,5Bp)12G2-
CONHCH
(R)-(4-3,4-4-3,5Bp)12G2-
CONHCH(CH3)C2H5 (38), re-
(CH3)C2H5 (37) and
AHCTREUNG
spectively. Dendrons 37 and 38
were obtained in 65 and 70%
yields, respectively, after chro-
matographic purification on
basic alumina with CH2Cl2/ace-
tone mixture (20:1 ratio) as
eluent.
Scheme 4. Functionalization of the apex of (4-3,4-4-3,5Bp)12G2-X dendron and the retrostructural analysis of
the corresponding supramolecular dendrimers.
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Dendrimers
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The structures of all dendrons from Schemes 1–4 were
confirmed by a combination of analytical methods including
500 MHz 1H NMR and 125 MHz 13C NMR spectroscopy,
matrix-assisted laser desorption/ionization-time of flight
(MALDI-TOF) mass spectrometry, high-pressure liquid
chromatography (HPLC), and elemental analysis. In all
cases their purity was >99%.
The self-assembly in enantiomeric helical columns was
demonstrated in cyclohexane by CD experiments performed
with
(S)-
and
(R)-(4-3,4-4-3,5Bp)12G2-CONHCH-
AHCTREUNG
shows that all the supramolecular columns self-assembled
from achiral dendrons exhibit a helical structure in solid
state. Therefore, these CD experiments demonstrate that
the stereocenter attached to the apex of the (4-3,4-4-
Helical structure by XRD and CD experiments: Wide-angle
XRD obtained on aligned fibers of (S)-(4-3,4-4-
3,5Bp)12G2-CONHCH(CH3)C2H5 dendron only selects the
C
3,5Bp)12G2-CONHCH
A
The helical structure of the supramolecular columns is in-
duced by the noninteger number of dendrons (m) required
to form the column stratum. The value of m varies from 6.3
to 13.4 for the supramolecular columns (Table 4; see later).
This result is similar to that observed for the case of helical
pores self-assembled from dendritic dipeptides.[3]
208C after 9 h annealing at 908C were used to indicate the
helical structure of the porous columns in solid state
(Figure 1). Figure 1a shows the appearance of X-shaped dif-
fractions (t), which are correlated to the tilt angle of the
dendritic molecules (408). In addition, X-shaped diffractions
(i) with very high intensity represent short-range intracolum-
nar helical correlation with a repeat distance of 4.5 Š.
The self-assembly in cyclohexane of (S)- and (R)-(4-3,4-4-
3,5Bp)12G2-CONHCH(CH3)C2H5 (37 and 38, respectively)
G
enantiomeric pairs is demonstrated by the CD and UV/Vis
spectra shown in Figure 2. The CD spectra of the supra-
molecular columns assembled from the two stereoisomers
are concentration and temperature dependent and also are
mirror images (Figure 2a, b). This is indicated by the values
and the signs of the ellipticity of the Cotton effects at 223,
237, and 280 nm. The Cotton effects at 223 and 237 nm (Fig-
ure 2a, b) show the signature of an exciton coupling, as sug-
gested by their zero crossover that corresponds to the maxi-
mum of the 227 nm from the UV/Vis absorption spectrum
(Figure 2c, d). Both left- and right- handed supramolecular
structures are stable in solution up to 368C (lower right side
insets in Figure 2a and b). The high-temperature stability of
the supramolecular structures in solution is desirable for
practical applications as membrane channels.[3a] Such experi-
ments will be reported elsewhere. These results demonstrate
the helical arrangement of the (4-3,4-4,3,5Bp)12G2-
CONHCH(CH3)C2H5 dendrons in their supramolecular
G
structure.
Electron-density maps of the porous hexagonal periodic
array: A representative example for the calculation of the
Dpore of the supramolecular columns self-organized in the
hexagonal columnar phase is provided for (S)-(4-3,4-4-
3,5Bp)12G2-CONHCH
general method were published.[3f] Electron-density distribu-
tion maps were reconstructed from the F(hkl) peak ampli-
(CH3)C2H5 (37). The details of this
AHCTREUNG
tudes, which were extracted from the small-angle powder
XRD (Figure 3). The enhanced amplitudes of the (11) and
(20) diffractions indicate a porous column.[3a] The XRD pat-
tern from Figure 3c shows seven diffraction peaks in the Fh
phase. All peaks were used in the calculation of the elec-
tron-density maps. Table 1 summarizes the experimental
small-angle XRD data collected at 908C along with the fol-
lowing parameters: p6mm lattice peak indices (hk), peak
multiplicity (m), experimental scattering vector (qmeas), cal-
Figure 1. Wide-angle XRD patterns of aligned fibers of (S)-(4-3,4-4-
3,5Bp)12G2-CONHCH(CH3)C2H5 collected a) at 348C and b) at 208C
A
after 9 h of annealing at 908C (the inset depicts also the small angle fiber
pattern), and the corresponding azimuthal angle Chi plots (c). e=4.3Š
diffuse equatorial feature; s=4.3Š stacking along the column axis fea-
ture; l=helical layer line; (hkl): high-order (hk0) reflections; (10), (11):
(hk) reflections of the hexagonal lattice; t=dendron tilt angle feature
(ꢁ408); i=short range helical feature (ꢁ4.5 Š).
culated scattering vector (qcalcd), measured d-spacings (d),
pffiffiffiffiffiffiffiffiffiffiffiffiffi
peak area (A), peak amplitude ( qA=m) and scaled ampli-
tude (Amplitude).
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V. Percec et al.
Figure 4a demonstrates three
separated regions. The periph-
ery of the column (marked in
dark gray) indicates the low
electron density that corre-
sponds to the aliphatic part of
the dendron. A lower electron
density than that found for the
aliphatic region is observed at
the center of the columns
(marked in darker gray). A
high electron-density area gen-
erated by the aromatic part of
the dendron surrounds this
region. The electron-density
maps from Figure 4 indicate
that the self-assembly of (S)-
(4-3,4-4-3,5Bp)12G2-
CONHCH
A
den-
drons generates porous col-
umns. However, the electron-
density maps from Figure 4 do
not allow the calculation of the
pore diameter (Dpore).
Calculation of Dpore of the
porous columns: The pore di-
mensions were determined by
using a simplified three-level
model of self-assembled supra-
molecular columns[3a,f] repre-
sented by three concentric cy-
lindrical shells. Each shell is
approximated by
a constant
electron-density level. This
model was used to reconstruct
the peak amplitudes of the
powder XRD pattern by
means of a least-square fitting
of calculated values to the ex-
perimental peak amplitudes.
The three-level model is con-
structed from a hollow core
that has the lowest electron-
density level, a high electron-
density region surrounding the
pore that corresponds to the
aromatic part of the (S)-(4-3,4-
4-3,5Bp)12G2-CONHCH-
Figure 2. CD spectra of a) (R)-(4-3,4-4-3,5Bp)12G2-CONHCH
CONHCH
(CH3)C2H5 in cyclohexane (1.6”10ꢀ4 m): a plot of q at 280 nm is shown as a bottom inset in both a)
and b); UV spectra of c) (R)-(4-3,4-4-3,5Bp)12G2-CONHCH(CH3)C2H5 and d) (S)-(4-3,4-4-3,5Bp)12G2-
CONHCH
(CH3)C2H5 in cyclohexane (1.6”10ꢀ4 m) exhibiting an isosbestic points at 222 and 244 nm; bottom
insets shows the plots of A230 as a function of temperature.
A
ACHTREUNG
AHCTREUNG
ACHTREUNG
A
a low
Reconstructed electron-density maps were generated by
P
using the equation 1(r)=
Fhkleꢀ2pi(hx+ky+lz)
,
in which
The electron densities in each level of the model are cal-
culated from the number of electrons present in the aromat-
ic and aliphatic parts of the chemical structure of the (S)-(4-
h,k,l
pffiffiffiffi
jFhkl jꢁ A and A is the peak area.[3a,f]
The gray-scale code on the electron-density distribution
3,4-4-3,5Bp)12G2-CONHCH
A
map with boundaries of electron-density values presented in
that is, Narom =612 and Naliph =388.[3a,f] Figure 5a shows the
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Dendrimers
FULL PAPER
Figure 3. a) Small-angle XRD pattern and plots in b) linear scale and c) log scale for the (S)-(4-3,4-4-3,5Bp)12G2-CONHCH(CH3)C2H5 in the porous
A
hexagonal columnar phase. In b) and c) the dotted lines indicate the expected (hk) peak positions based on the Fh with the lattice dimension a=80.97 Š
(Table 1).
Figure 4. a) 2D view and b) 3D surface view of the reconstructed electron-density maps generated by the measured amplitudes from Table 1.
Figure 5. a) The agreement between the measured (filled circles) and three-level fitted (empty squares) amplitudes for the (S)-(4-3,4-4-3,5Bp)12G2-
CONHCH
A
G
(x,y)ꢀ1fitted
(x,y); the overall dif-
ference is less than 5%, with a maximum difference of about 15% localized in the aliphatic region along the direction of the column close-contact.
accuracy of the fit between the experimental and the model
amplitudes. As observed from Figure 5b the overall differ-
ence between electron densities calculated from the experi-
mental and fitted amplitudes is less than 5%. The maximum
difference of ꢁ15% is located in the aliphatic region of the
columns along the direction of their close-contact (Fig-
ure 5b).
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V. Percec et al.
Amplitude[g]
Table 1. Powder XRD data for (S)-(4-3,4-4-3,5Bp)12G2-CONHCH(CH3)C2H5 collected at 908C.
A
pffiffiffiffiffiffiffiffiffiffiffiffiffi
[c]
ꢀ1
[d]
ꢀ1
h[a]
k[a]
m[b]
qmeas [Š
]
qcalc [Š
]
d[e] [Š]
A[f]
qA=m
1
1
2
2
3
2
3
0
1
0
1
0
2
1
1
1
1
2
1
1
2
0.0893
0.1553
0.1796
0.2378
0.2688
0.3108
0.3240
0.0896
0.1552
0.1792
0.2370
0.2688
0.3104
0.3230
70.343
40.461
34.984
26.424
23.375
20.214
19.393
779.858
204.391
174.678
3.300
0.326
1.284
8.346
5.634
5.601
0.626
0.296
0.632
0.671
38.275
25.836
25.686
2.872
1.357
2.897
3.077
2.779
pffiffiffiffiffiffiffiffiffiffiffiffiffiffi
h2 þk2
[a] p6mm lattice peak index. [b] Peak multiplicity. [c] Experimental scattering vector. [d] Calculated scattering vector using q(hk)=4p
þhk, with the
pffiffiffi
ꢀ
3a
ꢀ
ꢁ
pffiffi
4p1
3
3
1
3
2
2p
pffiffi
lattice parameter a given by a¯ =
+
+
=80.97 Š. [e] Measured (hk) peak d-spacing computed using d=q . [f] (hk) peak area. [g] Scaled
qð10Þ
qð11Þ
qð20Þ
meas
qffiffiffiffiffiffiffiffiffiffiffi
P
Area
ðhkÞ
amplitude calculated using the scaling factor given by S=
=21.806.
qhk
m
ðhkÞ
ðhkÞ
Structural and retrostructural analysis: All hybrid dendrons
self-assemble in columnar supramolecular dendrimers that
self-organize in various periodic arrays. The phase behavior
of all supramolecular dendrimers was analyzed by a combi-
nation of thermal optical polarized microscopy (TOPM),
differential scanning calorimetry (DSC), and small- and
wide-angle XRD performed as a function of temperature on
powder and oriented fibers. The powder XRD experiments
were carried out during first and second heating cycles up to
the isotropic state and on cooling scans.
The fiber experiments were performed below the isotropic
state. Structural and retrostructural analysis was performed
by using methods elaborated previously.[3] The transition
temperatures (8C) and the corresponding enthalpy changes
(kcalmolꢀ1) were determined by DSC with heating and
cooling rates of 108Cminꢀ1. DSC traces obtained from the
first and second heating and from the first cooling scans for
the hybrid dendrons from Schemes 1–3are shown in
Figure 6.
Figure 6. DSC traces (108Cminꢀ1) of supramolecular dendrimers self-assembled from hybrid dendrons. Transition temperatures (8C) and enthalpy
changes (in parantheses, kcalmolꢀ1) are marked in the figure: a) first heating scan; b) first cooling scan; c) second heating scan. Peak intensities are not
scaled.
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Dendrimers
FULL PAPER
Figure 7 shows the DSC traces collected on the first and
second heating and the first cooling scans for (4-3,4-4-
3,5Bp)12G2-X, in which X represents the functional groups
at the apex of the self-assembling dendrons (Scheme 4). The
DSC traces marked “blend” at the bottom of Figure 7 show
the thermal behavior of a mixture of seven hybrid dendrons
(4-3,4-4-3,5Bp)12G2-X bearing -H, -CO2CH3, -CH2OH,
dendrons. They self-organize in a variety of liquid crystal-
line, crystalline, and ordered glassy phases.
All columnar phases were analyzed and assigned by XRD
experiments. The d-spacing, their indices, and lattice symme-
tries are reported in Table 3.
Table 4 summarizes the lattice parameters (a) for the hex-
agonal columnar (Fh) or (a,b) for the columnar rectangular-
centered (Fr-c) and columnar rectangular simple (Fr-s) latti-
ces; the column diameters (Dcol, Da, Db); the pore diameters
(Dpore) for columnar hexagonal phases; the experimental
densities (120); the number of dendrons per 4.7 Š supra-
molecular column stratum (m); and the projection of the
solid angle of the dendron (a’).[4a,c,d]
-CO
A
-CONH2,
-CONHCH3
or -(S)-
CONHCH
ACHTREUNG
mixed in 1:1:1:1:1:1:1 weight ratio and their DSC provided a
remarkable result. They are miscible, and their mixture pro-
vides a new mechanism to assemble supramolecular pores
containing statistically distributed functional groups in the
pore.
Table 2 summarizes the transition temperatures and corre-
sponding enthalpy changes obtained from Figures 6 and 7
for all supramolecular structures self-assembled from hybrid
The most representative results of the structural and ret-
rostructural analysis are summarized in Figures 8 and in
Scheme 4.
Figure 8a summarizes the self-assembly of six second-gen-
eration dendrons that have various combinations of 4’-, 3’,4’-
Figure 7. DSC traces (108Cminꢀ1) of (3-3,4-4-3,5Bp)12G2-X. Transition temperatures (8C) and enthalpy changes (in parantheses, kcalmolꢀ1) are marked
in the figure: a) first heating scan; b) first cooling scan; c) second heating scan. Peak intensities are not scaled. * Enthalpy change was calculated based
on overlapped peaks. ** Blend is a mixture of (3-3,4-4-3,5Bp)12G2-X, in which X=H, CO2CH3, CH2OH, CO2
A
CONHCH(CH3)C2H5 in 1:1:1:1:1:1:1 ratio.
ACHTREUNG
Chem. Eur. J. 2007, 13, 3989 – 4007
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
3997

V. Percec et al.
and 3’,5’-substituted biphenyl-4-methyl ether and 4-; 3,4-;
and 3,5-benzyl ether repeat units incorporated in the (4-3,4-
3,5)12G2-X primary structure that was employed previously
in the synthesis of dendritic dipeptides.[3]
D
pore =8.2 Š. Similarly, when the 3’,5’-biphenyl-4-carboxyl-
ate was attached to the apex and the 3’,4’- biphenyl-4-
methyl ether in the inner part generated (4-3,4Bp-
3,5Bp)12G2-CO2CH3 (17), which self-assembles into porous
columns. Alternatively, when 4’-substituted biphenyl-4-
methyl ether were incorporated on the periphery generated
(4Bp-3,4-3,5Bp)12G2-CO2CH3 (18) that self-assemble into
porous columns. The Dcol of (4-3,4Bp-3,5Bp)12G2-CO2CH3
The primary structures containing the 3’,5’-disubstituted
biphenyl-4-carboxylate at the apex ((4-3,4-3,5Bp)12G2-
CO2CH3, 3), the 4’-substituted biphenyl-4-methyl ether at
the periphery ((4Bp-3,4-3,5)12G2-CO2CH3, 16),and the 4’-
substituted biphenyl-4-methyl ether at the periphery togeth-
er with 3’,4’-disubstituted biphenyl-4-carboxylate in the
inner part of the dendron ((4Bp-3,4Bp-3,5)12G2-CO2CH3,
20) assemble into nonporous columns. However, the incor-
poration of the 3’,4’- biphenyl-4-methyl ether in the inner
part of a benzyl ether dendron that does not assemble into
porous columns generated (4-3,4Bp-3,5)12G2-CO2CH3 (10),
which does assemble into porous columns that self-organize
into an enantiotropic Fh phase with Dcol =68.1 Š and
and (4Bp-3,4-3,5Bp)12G2-CO2CH3 are similar: Dcol
=
73.5 Š and Dcol =72.5 Š, respectively. However, surprisingly,
Dpore is almost twice as small for (4Bp-3,4-3,5Bp)12G2-
CO2CH3 dendron Dpore =6.4 Š relative to Dpore =11.5 Š for
(4-3,4Bp-3,5Bp)12G2-CO2CH3. In addition, DSC analysis
of
(4-3,4-3,5Bp)12G2-CO2CH3,
(4-3,4Bp-3,5Bp)12G2-
CO2CH3, and (4Bp-3,4-3,5Bp)12G2-CO2CH3 supramolec-
ular dendrimers showed the following increasing trend of
Table 2. Thermal transitions of supramolecular dendrimers self-assembled from hybrid dendrons.
[a]
Dendron
Thermal transitions [8C] and corresponding enthalpy changes [kcalmolꢀ1
]
Heating
Cooling
(4-3,4-3,5Bp)12G2-CO2CH3
(4-3,4Bp-3,5)12G2-CO2CH3
(4Bp-3,4-3,5)12G2-CO2CH3
(4-3,4Bp-3,5Bp)12G2-CO2CH3
(4Bp-3,4-3,5Bp)12G2-CO2CH3
(4Bp-3,4Bp-3,5)12G2-CO2CH3
(4-3,4-42-3,5Bp)12G2-CO2CH3
(42-3,4-3,5Bp)12G2-CO2CH3
(42-3,4-4-3,5Bp)12G2-CO2CH3
(4-3,4-4-3,5Bp)12G2-H[c]
k 48.4 (0.91) Fr-s 84.4 (10.13) i
g 32.5 Fr-s 87.5 (5.55) i
g 43.4 69.0 (1.09) Fh 126.6 (5.56) i
g 43.5 Fh 126.5 (5.53) i
Fr-s 56.5 Fr-s 94.9 (13.93) Fh
g 81.1 Fh
g 50.9 Fh 92.0 (-6.95) Fh 112.9 (14.7) i
g 32.5 Fh 109.4 112.5 (8.31) i
k 90.8 (19.40) Fh 192.2 (7.83) i
g 51.5 Fh 191.6 (10.24) i
k 87.2 (14.56) Fr-c
g 90.7 (1.72) Fr-c
g 52.9 Fh 112.9 (0.98) Fr-s 120.3(4.69) i
g 52.2 Fh 112.8 (1.01) Fr-s 120.4 (4.53) i
g 48.6 Fh 143.5 (10.53) i
i 83.1 (5.28) Fr-s 29.4 g
i 121.6 (6.14) Fh 36.8 g
128.7 Fh 72.2 g
i 103.8 (5.12)Fh 45.0 g
i 186.8 (6.75)Fh 53.2 g
Fr-c 55.9 g
i 116.5 (4.83) Fr-s 109.9 (0.97) Fh 45.4 g
i 137.7 (10.31)Fh 44.5 g
i 147.7 (11.62)Fh 53.3 g
i 99.4 (7.00)Fh 44.8 g
g 44.0 Fh 142.9 (10.33) i
k 69.4 (7.51) Fh 152.4 (11.97) i
g 53.5 Fh 152.2 (11.85) i
k 50.9 (1.36) Fh 101.5 (6.73) i
g 45.7 Fh 101.4 (6.63) i
[c]
(4-3,4-4-3,5Bp)12G2-CO2CH3
(4-3,4-4-3,5Bp)12G2-CH2OH[c]
(4-3,4-4-3,5Bp)12G2-COOH
(4-3,4-4-3,5Bp)12G2-COOK
k 56.4 (1.88) Fh 97.9 99.9 (5.99)[b]
g 48.6 Fh 97.399.5 (5.64) [b] i
g 45.7 Fh 129.1 (6.07) i
g 49.9 Fh 128.9 (6.57) i
g 48.0 Fh 142.3(6.10) i
g 69.5 Fh 140.1 (5.91) i
k 58.9 (8.76) Fh 155.5 (0.19)
g 41.6 Fh 96.5 (6.29) i
i
i 99.5 (5.47)[b] 97.3 Fh 43.9 g
i 125.8 (6.59)Fh 47.3g
i 140.0 (5.91)Fh 60.8 g
[c]
(4-3,4-4-3,5Bp)12G2-CO2
(4-3,4-4-3,5Bp)12G2-CONH2
(4-3,4-4-3,5Bp)12G2-CONHCH3
(CH2)2OCH3
i 96.4 (6.31)[b] 94.5 Fh 36.2 g
i 156.6 (4.94)[b] 155.0 Fh 81.6 g
i 135.0 (4.97) Fh 60.7 g
i 114.1 (6.15) Fh 60.8 g
i 114.1 (6.28) Fh 60.2 g
i 110.7 (6.37)Fh 47.5 g
g 41.5 Fh 96.4 (6.31) i
[c]
g 71.8 Fh 156.7 158.2 (5.01)[b]
i
g 70.9 Fh 156.3157.7 (4.83) [b] i
[c]
Fr-s 64.4 (5.90) Fr-s 115.0 (9.44) Fh 139.9 (4.60) i
g 67.0 Fh 135.9 (4.53) i
g 60.9 Fh 115.3(6.38) i
g 66.7 Fh 115.1 (6.36) i
g 62.6 Fh 115.6 (6.65) i
[c]
(S)-(4-3,4-4-3,5Bp)12G2-CONHCH
(R)-(4-3,4-4-3,5Bp)12G2-CONHCH
blend[c]
G
G
g 66.7 Fh 115.3(6.50) i
g 48.0 Fh 112.3(5.92) i
g 54.0 Fh 113.5 (6.21) i
[a] Thermal transitions and enthalpy changes (in parantheses) were determined by DSC (108Cminꢀ1), data from the first heating and the first cooling is
on the first line, and the data from the second heating is on the second line. [b] Enthalpy changes based on overlapped peaks. [c] Dendrons included in
Blend in the 1:1:1:1:1:1:1 ratio; Fr-c =c2mm centered rectangular columnar lattice; Fr-s =p2mm simple rectangular columnar lattice; Fh =p6mm hexago-
nal columnar lattice; k=crystalline; g=glassy; i=isotropic.
3998
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Chem. Eur. J. 2007, 13, 3989 – 4007

Dendrimers
FULL PAPER
Figure 8. Retrostructural analysis of supramolecular dendrimers self-assembled from a) (4-3,4Bp)12G1-X, in which X=CO2CH3, CH2OH, and (4-3,4-
G
3,5)12G2-CO2CH3 hybrid dendrons containing benzyl ether and biphenyl-4-methyl ether repeat units and b) (4-3,4-3,5)12G2-X hybrid dendrons contain-
ing 4-, 3,4-benzyl, 3’,5’-biphenyl-4-methyl, and combinations of (AB)y-AB2 4-benzyl ether hybrid dendrons.
Chem. Eur. J. 2007, 13, 3989 – 4007
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
3999

V. Percec et al.
Table 3. Measured d-spacing [in Š] of p2mm simple rectangular columnar (Fr-s), c2mm centered rectangular columnar (Fr-c), and p6mm hexagonal col-
umnar (Fh) lattices generated by biphenyl–benzyl ether combined dendrons.
Dendron
T [8C]
Lattice
LC phase
d-spacings [Š] and their indices
[a]
[b]
[c]
d10
d20
d10
d11
d11
d11
d20
d31
d03
d21
d40
d20
d30
d02
d30
d22
d22
d01
d31
d21
(4-3,4-3,5Bp)12G2-CO2CH3
(4-3,4Bp-3,5)12G2-CO2CH3
(4Bp-3,4-3,5)12G2-CO2CH3
55
80
85
100
80
150
65
p2mm
p6mm
p2mm
p6mm
p6mm
p6mm
c2mm
p6mm
p2mm
p6mm
p6mm
p6mm
p6mm
p6mm
p6mm
p6mm
p6mm
p6mm
p2mm
p6mm
p6mm
p6mm
p6mm
Fr-s
Fh
Fr-s
Fh
Fh
Fh
Fr-c
Fh
Fr-s
Fh
Fh
Fh
Fh
Fh
Fh
Fh
Fh
Fh
Fr-s
Fh
Fh
Fh
Fh
53.7[c]
22.3
36.5
32.6
28.2
59.0[a]
63.0[c]
65.6[a]
63.4[a]
62.8[a]
87.4[b]
76.8[a]
64.3[c]
65.8[a]
79.7[a]
64.1[a]
66.1[a]
64.0[a]
61.5[a]
60.7[a]
67.5[a]
67.3[a]
66.4[a]
62.9[a]
70.6[a]
70.0[a]
64.2[a]
34.0
29.5
31.5
36.8
36.3
59.8
44.0
27.5
31.8
31.4
32.6
38.2
32.2
(4-3,4Bp-3,5Bp)12G2-CO2CH3
(4Bp-3,4-3,5Bp)12G2-CO2CH3
(4Bp-3,4Bp-3,5)12G2-CO2CH3
(4-3,4-42-3,5Bp)12G2-CO2CH3
24.1
30.5
28.8
90
21.1
114
115
100
80
32.1
21.9
(42-3,4-3,5Bp)12G2-CO2CH3
(42-3,4-4-3,5Bp)12G2-CO2CH3
(4-3,4-4-3,5Bp)12G2-H[d]
(4-3,4-4-3,5Bp)12G2-CO2CH3
(4-3,4-4-3,5Bp)12G2-CH2OH[d]
(4-3,4-4-3,5Bp)12G2-COOH
(4-3,4-4-3,5Bp)12G2-COOK
38.1
45.8
36.9
38.3
36.9
35.4
34.9
38.8
38.6
56.6
36.2
40.6
40.2
37.6
33.0
39.6
32.0
33.1
32.0
30.6
30.3
33.6
33.6
38.2
31.3
35.1
34.9
32.5
25.0
29.8
24.2
25.0
24.2
23.2
22.9
24.4
25.3
33.1
23.7
26.6
26.4
24.6
22.9
20.2
[d]
75
100
132
170
90
[d]
(4-3,4-4-3,5Bp)12G2-CO2
(4-3,4-4-3,5Bp)12G2-CONH2
(4-3,4-4-3,5Bp)12G2-CONHCH3
A
76
[d]
100
125
90
100
100
[d]
(S)-(4-3,4-4-3,5Bp)12G2-CONHCH
(R)-(4-3,4-4-3,5Bp)12G2-CONHCH
blend[d]
ACHTREUNG
A
[a] Hexagonal lattice p6mm (Fh). [b] Rectangular center lattice (Fr-c). [c] Rectangular simple lattice (Fr-s). [d] Dendrons included in Blend in the
1:1:1:1:1:1:1 ratio.
Table 4. Structural and retrostructural analysis of supramolecular dendrimers self-assembled from hybrid dendrons.
[a]
[g]
Dendron
T
[8C]
Lattice LC
hd100
i
a (a, b)
[Š]
Dcol (Da, Db) Dpore 120
m
a’[k]
Phase [Š]
[Š]
[Š]
A
(4-3,4-3,5Bp)12G2-CO2CH3
(4-3,4Bp-3,5)12G2-CO2CH3
(4Bp-3,4-3,5)12G2-CO2CH3
55
80
85
105
80
150
65
p2mm
p6mm
p2mm
p6mm
p6mm
p6mm
c2mm
p6mm
p2mm
p6mm
p6mm
p6mm
p6mm
p6mm
p6mm
p6mm
p6mm
p6mm
p2mm
p6mm
p6mm
p6mm
p6mm
Fr-s
109.5, 32.7[b]
68.1[a]
109.5, 32.7[f]
68.1[d]
1.09*
1.05
1.11
7.0[j]
7.2[h]
51.4
50.0
Fh
Fr-s
Fh
Fh
Fh
Fr-c
Fh
Fr-s
Fh
Fh
Fh
Fh
Fh
Fh
Fh
Fh
Fh
Fr-s
Fh
Fh
Fh
Fh
59.0
8.2
63.0, 32.2[b]
63.6[a]
63.0, 32.2[f]
63.6[d]
3.5[j] 102.5
55.1
63.6
62.8
6.3[h]
8.1[h]
7.5[h]
8.8[j]
57.1
44.4
48.0
40.9
34.6
(4-3,4Bp-3,5Bp)12G2-CO2CH3
(4Bp-3,4-3,5Bp)12G2-CO2CH3
(4Bp-3,4Bp-3,5)12G2-CO2CH3
(4-3,4-42-3,5Bp)12G2-CO2CH3
73.5[a]
73.5[d]
11.5
6.4
1.07
1.07
1.09
1.10
72.5[a]
72.5[d]
173.3, 65.0[c]
88.2[a]
100.1, 65.0[e]
88.2[d]
90
76.4
66.0
79.391.5
64.1
66.2
64.0
61.370.8
60.6
66.6
13.2
10.4[h]
114
115
100
80
64.3, 32.1[b]
64.3, 32.1[f]
76.2[d]
3.2[j] 112.5
(42-3,4-3,5Bp)12G2-CO2CH3
(42-3,4-4-3,5Bp)12G2-CO2CH3
(4-3,4-4-3,5Bp)12G2-H[m]
(4-3,4-4-3,5Bp)12G2-CO2CH3
(4-3,4-4-3,5Bp)12G2-CH2OH[m]
(4-3,4-4-3,5Bp)12G2-COOH
(4-3,4-4-3,5Bp)12G2-COOK
76.2[a]
10.4
11.1
11.6
11.5
10.6
9.2
5.5
12.0
10.1
1.09
1.10
1.09
1.08
1.09*
1.09*
1.09*
1.09*
1.09*
1.09*
7.7[h]
10.2[h]
8.4[h]
8.6[h]
8.2[h]
7.5[h]
7.2[h]
8.6[h]
9.0[h]
12.6[j]
7.8[h]
9.6[h]
9.4[h]
8.3[h]
46.6
35.3
42.9
41.9
43.4
48.0
50.0
41.9
40.0
28.64
6.2
[a]
91.5[d]
73.3[a]
76.4[a]
73.3[d]
[m]
75
76.4[d]
100
132
170
90
73.9[a]
73.9[d]
[a]
70.8[d]
70.0[a]
70.0[d]
[m]
(4-3,4-4-3,5Bp)12G2-CO2
(4-3,4-4-3,5Bp)12G2-CONH2
(4-3,4-4-3,5Bp)12G2-CONHCH3
A
76.9[a]
76.9[d]
[m]
76
67.1
77.4[a]
77.4[a]
[m]
100
125
90
100
100
66.1, 111.5[b]
72.4[a]
66.1, 111.5[f] 10.0
72.4[d]
62.7
70.4
69.8
64.9
[m]
(S)-(4-3,4-4-3,5Bp)12G2-CONHCH
(R)-(4-3,4-4-3,5Bp)12G2-CONHCH
blend
A
81.3[a]
81.3[d]
80.6[d]
74.9[d]
10.4
11.0
11.0
1.09*
1.09*
1.09*
37.5
38.3
13.4
U
80.6[a]
74.9[a]
pffiffi
pffiffiffiffiffiffiffiffiffiffi pffiffiffiffiffiffiffiffiffiffi pffiffiffiffiffiffiffiffiffiffi
[a] For p6mm hexagonal columnar lattice parameter a=2hd100
i
3; hd100i=(d100
+ 3d110 + 4d200 + 7d210)/4. [b] p2mm=simple rectangular columnar
lattice parameters a and b; a=hd, b=kd; (h0) and (k0) from diffractions. [c] c2mm=centered rectangular columnar lattice parameters a and b; a=hd,
pffiffiffi
b=kd; (h0) and (k0) from diffractions. [d] Experimental column diameter of p6mm hexagonal columnar lattice D=2hd100i/ 3. [e] Experimental elliptical
pffiffiffi
column diameters of c2mm centered rectangular columnar lattice Da =a/ 3 and Db =b. [f] Experimental elliptical column diameters of p2mm simple rec-
tangular columnar lattice. [g] 120=Experimental density at 208C. * In cases in which 1 was not measured, it is assumed to be 1.09 [gmLꢀ1]. [h] Number of
pffiffiffi
dendrons per p6mm hexagonal column stratum m=( 3NAD2t1)/2M. [i] Number of dendrons per elliptical c2mm centered rectangular column stratum m-
G
A
dendron a’=360/m [8]. Avogadroꢁs number NA =6.0220455”1023 molꢀ1, the average height of the column stratum t=4.7 Š, and M=molecular weight of
dendron. [m] Dendrons included in Blend in the 1:1:1:1:1:1:1 ratio.
4000
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Chem. Eur. J. 2007, 13, 3989 – 4007

Dendrimers
FULL PAPER
their isotropisation temperatures, 87.5, 112.5, and 191.68C,
respectively.
The (4-3,4-4-3,5Bp)12G2-CO2CH3 (29) dendron from
Figure 4 was selected to investigate the role of the nature of
the functional group from its apex on self-assembly. The
synthesis of dendrons (4-3,4-4-3,5Bp)12G2-X containing ten
different functional groups at the apex together with the
structural and the retrostructural analysis of their supra-
molecular dendrimers are summarized in Scheme 4.
Table 5 gives reaction conditions and lattice parameters
generated from the structural and retrostructural analysis of
the library of supramolecular dendrimers self-assembled
from the (4-3,4-4-3,5Bp)12G2-X dendrons. A large diversity
of functional groups that are able to promote hydrogen
bonding (-CH2OH, -COOH, -CONH2, -CONHCH3); ionic
interactions (-COOK); and achiral nonpolar (-H, -CO2CH3),
Second-generation hybrid dendrons obtained from combi-
nations of biphenyl-4-methyl ether and benzyl ether repeat
units tend to self-assemble exclusively into columns rather
than spheres. Supramolecular speres were commonly ob-
served in the case of biphenyl-4-methyl ether dendrons.[4b]
Figure 8b summarizes the self-assembly of the last group
of hybrid dendrons. They contain 3’,5’-disubstituted biphen-
yl-4-methyl ester at the apex and various combinations of
(AB)y-AB2 benzyl ether repeat units in the inner part of the
dendron such as in the case of (4-3,4-4-3,5Bp)12G2-
CO2CH3 (29) and (4-3,4-42-3,5Bp)12G2-CO2CH3 (27), on
the periphery of the dendron as in (42-3,4-3,5Bp)12G2-
CO2CH3 (25), and both in the inner part and on the periph-
ery of the dendron as in (42-3,4-4-3,5Bp)12G2-CO2CH3
(23). In this library of hybrid dendrons, the 4-biphenyl-4-
methyl ether-like repeat units were constructed from (AB)2
dimers generated from 4-benzyl ether as AB repeat units.
This is the most rewarding group of dendrons, since all of
them self-assemble into porous columns.
It is interesting to recall at this point that (4-3,4-
3,5)12G2-X[3a,e] self-assembles into nonporous columns. At
the same time, (4Bp-3,4Bp-3,5Bp)12G2-X self-assembles
into porous columns and supramolecular spheres.[4b] Howev-
er, the incorporation of hybrid repeat units from each of
them into the same (4-3,4-3,5)12G2-X primary structure in-
duces the assembly of porous columns and eliminates the
formation of supramolecular spheres. This is a remarkable
example of the influence of the nature of the repeat units of
an identical sequence of the primary structure of the den-
dron on the tertiary structure of its supramolecular assem-
bly. The molecular mechanism that generates this change is
not yet known.
achiral polar (-CO
ACHTREUNG
CONHCH(CH3)C2H5, -(S)-CONHCH
A
ACHTREUNG
tions are tolerated by this self-assembly process. This indi-
cates pathways to assemble a large diversity of functional
pores through very simple architectural principles.
The dependence of d-spacings and their amplitudes on
the structure of the functional group X from the apex of the
dendron is illustrated by the XRD plots in Figure 9. The in-
creased intensities of the higher order 11, 20, and 12 diffrac-
tion peaks indicate that the Fh phase is generated from
porous columns.[3,4a,b] These XRD data also demonstrate
that a mixture of seven dendritic dipeptides with the general
primary structure (4-3,4-4-3,5Bp)12G2-X containing a di-
versity of different X groups at the apex, X=H, CO2CH3,
CH2OH, CO2
CONHCH(CH3)C2H5 in a 1:1:1:1:1:1:1 (mass ratio) co-as-
semble in a porous structure with Dcol =74.9 Š and Dpore
A
AHCTREUNG
=
11.0 Š. This simple strategy opens new pathways to func-
tionalize the internal structure of the pore.
Table 5. Synthesis of the (4-3,4-4-3,5Bp)12G2-X library. The error of the Dpore is ꢂ1.2 Š.
Starting material
(4-3,4-4)12G2-CH2Cl
(4-3,4-4)12G2-CH2Cl
Reaction conditions
X
Yield
[%]
T[b]
[8C]
Lattice
parameters
G
21, K2CO3, DMF, 908C
2, K2CO3, DMF, 908C
LiAlH4, THF[a]
H
70
80
D
col =73.3 Š, Dpore =11.6 Š,
m=8.4 a’=42.98
col =76.4 Š, Dpore =11.5 Š,
m=8.6 a’=41.98
col =73.9 Š, Dpore =10.6 Š,
m=8.2 a’=43.48
col =70.0 Š, Dpore =5.5 Š,
m=7.2 a’=50.08
col =70.8 Š, Dpore =9.2 Š,
m=7.5 a’=48.08
col =76.9 Š, Dpore =12.0 Š,
m=8.6 a’=41.98
col =77.4 Š, Dpore =10.1 Š,
m=9.0 a’=40.08
col =72.4 Š, Dpore =10.0 Š,
m=7.8 a’=46.28
col =81.3Š, Dpore =10.4 Š,
m=9.6 a’=37.58
col =80.6 Š, Dpore =11.0 Š,
m=9.4 a’=38.38
G
CO2CH3
CH2OH
COOK
COOH
84
75
D
(4-3,4-4-3,5Bp)12G2-CO2CH3
(4-3,4-4-3,5Bp)12G2-CO2CH3
(4-3,4-4-3,5Bp)12G2-COOK
(4-3,4-4-3,5Bp)12G2-COOK
(4-3,4-4-3,5Bp)12G2-COOK
(4-3,4-4-3,5Bp)12G2-COOK
(4-3,4-4-3,5Bp)12G2-COOK
(4-3,4-4-3,5Bp)12G2-COOK
90
100
170
132
90
D
KOH, THF, EtOH, H2O, 60 8C
CH3CO2H, THF[a]
100
80
D
D
2-methoxyethanol, DCC, DPTS[a]
CO2
U
87
D
1. SOCl2, CH2Cl2
CONH2
61
76
D
[c]
2. NH3(g), CH2Cl2
NH2CH3.HCl, CDI, DPTS, Et3N[a]
CONHCH3
(S)-CONHCH
62
125
90
D
[a]
1. SOCl2, CH2Cl2
G
65
D
[a]
2. (S)-C2H5
1. SOCl2, CH2Cl2
2. (R)-C2H5
A
[a]
(R)-CONHCH
G
70
100
D
[a]
A
[a] The reaction was performed at 258C. [b] Temperature of XRD measurement. The error of m is 10%.
Chem. Eur. J. 2007, 13, 3989 – 4007
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
4001

V. Percec et al.
Assembling hybrid dendrons into phospholipids bilayers:
Figure 11 shows the UV spectra recorded during the self-as-
sembly in cyclohexane. Cyclohexane resembles the structure
Figure 9. Small-angle XRD plots of (4-3,4-4-3,5Bp)12G2-X dendrons
with the X-groups shown in the figure and of a blend of (4-3,4-4-
3,5Bp)12G2-X, with X=H, CO2CH3, CH2OH, CO2
ACHTREUNG
Figure 11. Small-angle XRD stack plots of the (4-3,4-4-3,5Bp)12G2-
CO2CH3/l-phosphatidylcholine mixture (1:7 mass ratio) at the indicated
temperatures. The peaks of the Fh phase generated from supramolecular
columns and the lipid peaks are indicated.
CONH2, CONHCH3, (S)-COHNCH
ACHTREUNG
ratio.
Model of supramolecular porous column: Molecular models
of a single porous column layer, the top view of the column,
the hydrogen-bonding network, and the cross-section of the
porous column for supramolecular porous dendrimer self-as-
of the aliphatic part of the phospholipid bilayers. Therefore,
by analogy to the case of dendritic dipeptides,[3a] it is expect-
ed that these dendrons self-assemble into porous columns in
the presence of phospholipids. This was indeed demonstrat-
ed by the XRD analysis of a mixture of 1/7 (mass ratio) of
(4,3,4-4-3,5Bp)12G2-CO2CH3 (29) with l-phosphatidylcho-
line (Figure 11).
sembled
from
(S)-(4-3,4-4-3,5Bp)12G2-CONHCH-
ACHTREUNG
and wide-angle fiber XRD experimental results are shown
in Figure 10.
X-ray diffraction patterns for the mixture at 25 and 808C
show the presence of the diffraction peaks resembling the
pattern defining the Fh lattice exhibited by the pure den-
dron at 808C, along with diffraction peaks characteristic for
the lipid. This demonstrates the microphase segregation of
hexagonal domains of supramolecular porous columns con-
sisting of 8ꢂ2 columns in a continuous phospholipid bilayer
containing 14ꢂ2 layers, as determined from the powder
XRD half-maxima peak widths. The domain size of the pure
columnar hexagonal phase generated from the same porous
columns is approximately two times larger.
Conclusion
In conclusion, the results reported here demonstrate that for
the same dendron primary structure, the sequence and struc-
ture of its repeat units provide a simple, powerful, and gen-
eral approach to the design and synthesis of hybrid den-
drons that self-assemble into helical pores. The range of
Dpore accomplished with the experiments reported here vary
between 6.4 and 12.0 Š. Therefore, this concept is comple-
mentary to that of dendritic dipeptides that produced
D
pore =8.7 to 15.8 Š.[3] These building blocks tolerate a large
Figure 10. (S)-(4-3,4-4-3,5Bp)12G2-CONHCH
model: a) one column stratum top view, b) detail of the pore region hy-
drogen-bonding network, c) pore cross-section, and d) top view.
A
molecular
diversity of functional groups at their apex and therefore,
provide the simplest method to assemble functional helical
4002
www.chemeurj.org
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2007, 13, 3989 – 4007

Dendrimers
FULL PAPER
compounds (M-H-W Laboratories, Phoenix, AZ) agree with the calculat-
pores. The principles by which the complex primary struc-
ture of hybrid dendrons determines the supramolecular
structure are not yet elucidated. However, the self-assembly
of hybrid dendrons with complex primary structure reported
here expands the scope and the limitations of the self-as-
sembling dendritic architectural motifs.[7]
ed value within ꢂ 0.4%.
Synthesis: The synthesis of
(4-3,4)12G1-CH2Cl (1),[4d] 3’,5’-dihydroxybi-
A
phenyl-4-carboxylic acid methyl ester (2),[4b] 3’,4’-dihydroxybiphenyl-4-
carboxylic acid methyl ester (4),[4b] 1-chloromethyl-4-(dodecyloxy)ben-
zene (5),[4d] 3,5-dihydroxybenzoic acid methyl ester (9),[4d] 3,4-dihydroxy-
benzoic acid methyl ester (11),[4d] 4-chloromethyl-4’-(dodecyloxy)biphenyl
(12),[4b] (4Bp-3,4Bp)12G1-CH2Cl (19),[4b] 3,5-dimethoxybiphenyl (21),[8]
A
(42-3,4)12G1-CH2Cl (24),[4c]
G
AHCTREUNG
Experimental Section
according to literature procedures. All new dendrons were synthesized
using the previously reported convergent iterative strategy.[3a, 4b–d,5a,8,9]
Materials: Al2O3 (activated, basic, Brokmann I, standard grade,
ꢁ150 mesh, 58 Š) and silica gel (ICN EcoChrom SiliTech 23-63D 60 Š)
were used as received. THF, dioxane and Et2O (Fisher, A.C.S. reagents)
were refluxed over sodium ketyl and freshly distilled before use. CH2Cl2
(Fisher, A.C.S. reagent) was refluxed over CaH2 and freshly distilled
before use. MeOH, EtOH, DMSO, CHCl3, DMF, toluene, Na2S2O3,
KOH, MgSO4, K2CO3, acetic acid (Fisher, A.C.S. reagents) were used as
received. Pyridine and 2,6-di-tert-butyl-4-methyl pyridine (DTBMP)
(from Lancaster) were used as received. Neutral chromatographic Al2O3,
SOCl2 (97%), LiAlH4 (95+ %), (from Aldrich) were used as received. 2-
Methoxy-ethanol, N,N’-dicyclohexylcarbodiimide (DCC), carbonyl diimi-
dazolide (CDI), and methylammonium chloride were purchased from
Acros, and (R)-(ꢀ)-sec-butylamine, (S)-(+)-sec-butylamine and DPTS
were purchased from Aldrich.
Techniques: 1H NMR (200, 250 and 500 MHz) spectra were recorded on
a Bruker DRX500 instrument. 13C NMR (90 MHz, 125 MHz) spectra
were recorded on a Bruker DRX 500 spectrometer. Melting points were
measured by using a uni-melt capillary melting point apparatus (Arthur
H. Thomas Company, Philadelphia, USA) and are uncorrected. Thin-
layer chromatography (TLC) was performed on precoated TLC plates
(silica gel with F254 indicator; layer thickness, 200 mm; particle size, 5–
25 mm; pore size, 60 Š, SIGMA-Aldrich). HPLC analyses were per-
formed on a Shimadzu LC-10 AT high-pressure liquid chromatograph
equipped with CTO-10 A column oven (408C), PE Nelson Analytical 900
Series integrator data station, Shimadzu RID-10 A RI detector, SPD-
10 A UV-Vis detector (254 nm), and a PL gel column (5 mm, 100 Š).
Methyl 3,5-bis
boxylate [(4-3,4-3,5Bp)12G2-CO2CH3] (3):
ACHTREUNG
A
(0.42 g, 3.00 mmol) in DMF (10 mL) was thoroughly degassed. Com-
pounds 2 (122 mg, 0.5 mmol) and 1 (714 mg, 1.01 mmol) were added. The
reaction mixture was heated to 908C under Ar for 20 h, then allowed to
cool to 258C and poured into water (100 mL). The formed precipitate
was filtered, dissolved in CH2Cl2 and precipitated with MeOH. A color-
less solid (0.60 g, 76%) was obtained by recrystallization from acetone.
Purity (HPLC): 99+ %; Rf =0.75 (hexane/EtOAc 4:1); 1H NMR
(500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=6.3Hz, 12H), 1.27 (m,
64H), 1.43(m, 8H), 1.79 (m, 8H), 3.94 (overlapped m, 11H), 4.98 (s,
4H), 5.07 (s, 8H), 6.62 (t, J=2.2 Hz, 1H), 6.83(d, J=2.1 Hz, 2H), 6.86
(m, 8H), 6.95 (s, 4H), 7.07 (s, 2H), 7.32 (d, J=4.6 Hz, 8H), 7.61 (d, J=
8.2 Hz, 2H), 8.09 ppm (d, J=8.2 Hz, 2H); 13C NMR (500 MHz, CDCl3,
258C, TMS): d=14.3, 22.9, 26.3, 29.6, 29.7, 29.8, 29.9, 32.2, 52.3, 68.3,
70.5, 71.6, 102.0, 107.1, 114.7, 115.3, 115.8, 121.2, 127.3, 129.2, 129.3,
129.4, 130.2, 130.3, 142.4, 145.7, 149.4, 149.7, 159.2, 160.6 ppm; MS
(MALDI-TOF): m/z calcd for C104H144O12
: 1585.1; found: 1608.3
[M+Na]+; elemental analysis calcd (%) for C104H144O12: C 78.68, H 9.15;
found: C 78.68, H 9.27.
Methyl
3,4Bp)12G1-CO2CH3] (6): A suspension of K2CO3 (2.14 g, 15.45 mmol)
in DMF (150 mL) was thoroughly degassed. Compounds (1.26 g,
3,4-bis(4-dodecyloxybenzyloxy)biphenyl-4-carboxylate
[(4-
4
5.15 mmol) and 5 (3.20 g, 10.29 mmol) were added. The reaction mixture
was heated to 908C under Ar for 15 h, then allowed to cool to 258C and
poured into water (300 mL). The formed precipitate was filtered, dis-
solved in CH2Cl2 and precipitated with MeOH. A colorless solid (3.64 g,
89%) was obtained by recrystallization from acetone. Purity (HPLC):
THF (Fisher HPLC grade) was used as eluent at
a flow rate of
4 mLminꢀ1. GC analysis was performed on a Hewlett–Packard HP68 gas
chromatograph. Thermal transitions were measured on a TA Instruments
2920 modulated differential scanning calorimeter (DSC). In all cases,
heating and cooling rates were 108Cminꢀ1. 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 opti-
cal polarized microscope (100”magnification) equipped with a Mettler
FP 82 hot stage and a Mettler FP 80 central processor was used to verify
thermal transitions. Small- and wide-angle X-ray diffraction measure-
ments were carried out with CuKa radiation from a Bruker-Nonius FR-
591 rotating anode X-ray source with a 0.2”2.0 mm2 filament operated
at 3.4 kW. The beam was collimated and focused by a single bent mirror
1
99+ %; Rf =0.40 (CH2Cl2); H NMR (500 MHz, CDCl3, 258C, TMS): d=
0.89 (t, J=6.3 Hz, 6H), 1.28 (m, 32H), 1.47 (m, 4H), 1.80 (m, 4H), 3.94
(s, 3H), 3.97 (t, J=6.6 Hz, 4H), 5.12 (s, 2H), 5.14 (s, 2H), 6.89 (d, J=
8.7 Hz, 4H), 7.01 (d, J=8.3Hz, 1H), 7.16 (d, J=8.3Hz, 1H), 7.22 (s,
1H), 7.36 (m, 4H), 7.56 (d, J=8.3Hz, 2H), 8.06 ppm (d, J=8.3Hz, 2H);
13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.3, 22.9, 26.3, 29.6, 29.7,
29.9, 32.2, 52.3, 68.3, 71.5, 71.9, 114.8, 115.1, 115.8, 120.8, 126.8, 129.2,
129.3, 129.4, 130.3, 145.5, 149.8, 159.3, 167.3 ppm; elemental analysis
calcd (%) for C52H72O6: C 78.75, H 9.15; found: C 78.60, H 9.25.
[3’,4’-Bis(4’-dodecyloxybenzyloxy)biphenyl-4-yl]methanol
[(4-
3,4Bp)12G1-CH2OH] (7): Dendron 6 (2.80 g, 3.22 mmol) was added to a
suspension of LiAlH4 (0.30 g, 7.82 mmol) in THF (100 mL). Reaction
mixture was stirred at 258C for 2 h, quenched by addition of water and
15% (w/v) NaOH, filtered through Celite, concentrated, and precipitated
with MeOH. The precipitate was filtered. The product (2.52 g, 84%) was
obtained by recrystallization from acetone. Purity (HPLC): 99+ %; Rf =
0.40 (CHCl3); 1H NMR (500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=
6.3 Hz, 6H), 1.29 (m, 32H), 1.47 (m, 4H), 1.80 (m, 4H), 3.96 (t, J=
6.6 Hz, 4H), 4.73(d, J=6.0 Hz, 2H), 5.11 (s, 2H), 5.14 (s, 2H), 6.89 (d,
J=8.7 Hz, 4H), 7.01 (d, J=8.3Hz, 1H), 7.12 (d, J=8.3Hz, 1H), 7.20 (s,
1H), 7.36 (m, 4H), 7.41 (d, J=8.3Hz, 2H), 7.50 ppm (d, J=8.3Hz, 2H);
13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.4, 22.9, 26.3, 29.6, 29.6,
29.7, 29.8, 29.9, 32.2, 65.4, 68.3, 71.6, 71.8, 114.8, 115.1, 116.0, 120.4, 127.2,
127.7, 129.3, 129.4, 134.7, 139.7, 140.6, 149.2, 149.6, 159.2 ppm; elemental
analysis calcd (%) for C51H72O5: C 80.06, H 9.49; found: C 80.22, H 9.45.
and sagitally focusing Ge(111) monochromator, resulting in a 0.2”
A
0.2 mm2 spot on a multiwire detector 125 cm from the sample. To mini-
mize 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 (ꢂ 0.18C)
oven. Matrix-assisted laser desorption/ionization-time of flight (MALDI-
TOF) mass spectra were recorded on a PerSpective Biosystems Voyager
DE spectrometer by using 2-(4-hydroxyphenylazo)-benzoic acid as
matrix. Angiotensin I and des-Arg1-Bradykinin were used as standards.
Sample preparation was as follows. The matrix (ca. 10 mg) was dissolved
in THF (1 mL). The sample (ca. 10 mg) was also dissolved in THF
(1 mL). The matrix solution (50 mL) and the sample solution (10 mL)
were mixed. To the mixture, a solution of AgTFA in THF (10 mL;
1 mgmLꢀ1) was added, and the mixture was mixed well. The mixture
(5 mL) was loaded on a MALDI plate, and air-dried before inserting into
the vacuum chamber of the MALDI instrument. Mass spectra were run
by direct sample introduction on a LCMS (Micromass) platform (elec-
tron spray ionizer, electron energy 70 eV). Elemental analyses of all new
4-Chloromethyl-3’,4’-bis(4’-dodecyloxybenzyloxy)biphenyl
[(4-
3,4Bp)12G1-CH2Cl] (8): Dendron 7 (2.25 g, 2.94 mmol) and DTBMP
(1.21 g, 5.88 mmol) were dissolved in CH2Cl2 (120 mL). SOCl2 (0.32 mL,
Chem. Eur. J. 2007, 13, 3989 – 4007
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
4003

V. Percec et al.
4.41 mmol) was added. The reaction mixture was stirred at 258C for 3h,
concentrated on rotary evaporator at 258C to 20 mL and precipitated by
MeOH at 08C. The precipitate was filtered and quickly purified by
column chromatography (SiO2, CH2Cl2/hexane 2:1) to give a colorless
136.0, 136.0, 140.8, 149.1, 149.7, 159.2 ppm; elemental analysis calcd (%)
for C57H76O5: C 81.380, H 9.11; found: C 81.18, H 9.00.
3,4-Bis(4’-dodecyloxybiphenyl-4-ylmethoxy)benzyl
chloride
[(4Bp-
3,4)12G1-CH2Cl] (15): Dendron 14 (0.95 g , 1.13mmol) and DTBMP
(0.37 g, 1.81 mmol) were dissolved in CHCl3 (200 mL). SOCl2 (2.6 mL of
0.57m solution, 1.47 mmol) dissolved in dry CH2Cl2 was added. The reac-
tion mixture was stirred at 258C for 2 h, concentrated on rotary evapora-
tor at 258C to 20 mL, and precipitated with MeOH at 08C. The precipi-
tate was filtered and quickly purified by column chromatography (SiO2,
CH2Cl2) to give a colorless solid (0.40 g, 42%). Purity (HPLC): 99+ %;
Rf =0.95 (CH2Cl2); 1H NMR (500 MHz, CDCl3, 258C, TMS): d=0.89 (t,
J=6.3Hz, 6H), 1.29 (m, 32H), 1.47 (m, 4H), 1.82 (m, 4H), 4.01 (t, J=
6.5 Hz, 4H), 4.64 (s, 2H), 5.20 (s, 4H), 6.90–7.00 (overlapped m, 6H),
7.03(s, 1H), 7.46–7.56 ppm (overlapped m, 12H); 13C NMR (500 MHz,
CDCl3, 258C, TMS): d=14.5, 23.1, 26.5, 29.8, 30.0, 30.1, 32.3, 65.7, 68.6,
71.6, 71.8, 114.7, 115.2, 115.9, 120.7, 127.2, 128.2, 128.5, 133.5, 134.9,
136.0, 136.0, 140.8, 149.1, 149.7 ppm.
1
solid (1.67 g, 74%). Purity (HPLC): 99+ %; Rf =0.95 (CH2Cl2); H NMR
(500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=6.3Hz, 6H), 1.29 (m,
32H), 1.47 (m, 4H), 1.80 (m, 4H), 3.96 (t, J=6.6 Hz, 4H), 4.63(s, 2H),
5.11 (s, 2H), 5.14 (s, 2H), 6.89 (d, J=8.7 Hz, 4H), 7.00 (d, J=8.3Hz,
1H), 7.11 (d, J=8.3Hz, 1H), 7.18 (s, 1H), 7.36 (m, 4H), 7.42 (d, J=
8.3Hz, 2H), 7.49 ppm (d, J=8.3Hz, 2H); 13C NMR (500 MHz, CDCl3,
258C, TMS): d=14.4, 22.9, 26.3, 29.6, 29.7, 29.9, 32.2, 68.3, 71.6, 71.8,
114.8, 115.1, 115.3, 116.0, 120.4, 127.2, 127.7, 129.3, 134.7, 139.7, 140.6,
149.2, 149.6, 159.2 ppm; elemental analysis calcd (%) for C51H71ClO4: C
78.17, H 9.13; found: C 78.65, H 9.31.
3’,5’-Bis[3’,4’-bis(4’-dodecyloxybenzyloxy)biphenyl-4-ylmethoxy] benzoic
acid methyl ester [(4-3,4Bp-3,5)12G2-CO2CH3] (10): A suspension of
K2CO3 (0.60 g, 4.36 mmol) in DMF (50 mL) was thoroughly degassed.
Compound 9 (92 mg, 0.54 mmol) and dendron 8 (810 mg, 1.09 mmol)
were added. The reaction mixture was heated to 908C under Ar for 15 h,
then allowed to cool to 258C and poured into water (150 mL) and ex-
tracted with CH2Cl2 (2”100 mL) and with CHCl3 (2”100 mL). The or-
ganic extracts were washed with water (100 mL), concentrated, and pre-
cipitated by MeOH. The precipitate was filtered, dried, and purified by
column chromatography (SiO2, CH2Cl2) to yield a colorless solid (0.67 g,
74%). Purity (HPLC): 99+ %; Rf =0.40 (CH2Cl2); 1H NMR (500 MHz,
CDCl3, 258C, TMS): d=0.89 (t, J=6.3H, 12Hz), 1.27 (m, 64H), 1.43(m,
8H), 1.79 (m, 8H), 3.92 (s, 3H), 3.97 (t, J=6.7 Hz, 8H), 5.11 (s, 8H),
5.13(s, 4H), 6.84 (t, J=2.2 Hz, 1H), 6.89 (d, J=8.7 Hz, 8H), 7.00 (d, J=
8.5 Hz, 2H), 7.12 (d, J=2.2 Hz, 2H), 7.20 (s, 2H), 7.33 (d, J=2.9 Hz,
2H), 7.37 (overlapped m, 8H), 7.46 (d, J=8.3Hz, 4H), 7.52 ppm (d, J=
8.3Hz, 4H); 13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.4, 23.0,
26.4, 29.6, 29.7, 29.9, 30.0, 32.2, 52.6, 68.4, 70.5, 71.7, 71.9, 107.7, 108.8,
114.8, 114.9, 115.1, 116.0, 120.6, 127.3, 128.3, 129.3, 129.5, 132.4, 134.6,
135.3, 141.1, 149.3, 149.7, 159.3, 160.2, 167.1 ppm; MS (MALDI-TOF): m/z
calcd for C110H148O12: 1661.1; found: 1684.8 [M+Na]+; elemental analysis
calcd (%) for C110H148O12: C 79.48, H 8.97; found: C 79.29, H 8.78.
3’,5’-Bis[3’,4’-bis(4’-dodecyloxybiphenyl-4-ylmethoxy)benzyloxy] benzoic
acid methyl ester [(4Bp-3,4-3,5)12G2-CO2CH3] (16): A suspension of
K2CO3 (48 mg, 0.348 mmol) in DMF (30 mL) was thoroughly degassed.
Compound 9 (19 mg, 0.116 mmol) and dendron 15 (200 mg, 0.233 mmol)
were added. The reaction mixture was heated to 908C under Ar for 20 h,
then allowed to cool to 258C and poured into water (100 mL) and ex-
tracted with CH2Cl2 (4”150 mL). The organic extracts were washed with
water (100 mL), concentrated, and precipitated with MeOH. The precipi-
tate was filtered, dried, and purified by column chromatography (SiO2,
CHCl3) to yield a colorless solid (77 mg, 37%). Purity (HPLC): 99+ %;
Rf =0.20 (CHCl3); 1H NMR (500 MHz, CDCl3, 258C, TMS): d=0.89 (t,
J=6.3Hz, 12H), 1.27 (m, 64H), 1.43 (m, 8H), 1.79 (m, 8H), 3.90 (s,
3H), 4.00 (m, 8H), 4.96 (s, 4H), 5.19 (s, 8H), 6.75 (t, J=2.3Hz, 1H),
6.96 (overlapped m, 12H), 7.08 (m, 2H), 7.45–7.55 ppm (overlapped m,
26H); 13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.4, 23.0, 26.4, 29.6,
29.7, 29.9, 30.0, 32.2, 52.6, 68.4, 70.5, 71.7, 71.9, 107.7, 108.8, 114.8, 114.9,
115.1, 116.0, 120.6, 127.3, 128.3, 129.3, 129.5, 132.4, 134.6, 135.3, 141.1,
149.3, 149.7, 159.3, 160.2, 167.1 ppm; MS (MALDI-TOF): m/z calcd for
C122H156O12: 1813.2; found: 1837.0 [M+Na]+; elemental analysis calcd
(%) for C121H156O12: C 81.35, H 8.80; found: C 81.16, H 8.62.
3,4-Bis(4’-dodecyloxy-biphenyl-4-yl-methoxy)benzoic acid methyl ester
[(4Bp-3,4)12G1-CO2CH3] (13):
A
suspension of K2CO3 (1.61 g,
Methyl 3’,5’-bis[3’,4’-bis(4’-dodecyloxybenzyloxy)biphenyl-4-yl-methoxy]-
biphenyl-4-carboxylate [(4-3,4Bp-3,5Bp)12G2-CO2CH3] (17): A suspen-
sion of K2CO3 (0.60 g, 4.36 mmol) in DMF (50 mL) was thoroughly de-
11.63mmol) in DMF (120 mL) was thoroughly degassed. Compounds 11
(0.65 g, 3.88 mmol) and 12 (3.00 g, 7.75 mmol) were added. The reaction
mixture was heated to 908C under Ar for 15 h, then allowed to cool to
258C and poured into water (300 mL). The precipitate formed was fil-
tered, dissolved in CH2Cl2, and precipitated with MeOH. A colorless
solid (3.08 g, 91%) was obtained by recrystallization from acetone. Purity
(HPLC): 99+ %; Rf =0.80 (CH2Cl2); 1H NMR (500 MHz, CDCl3, 258C,
TMS): d=0.89 (t, J=6.3Hz, 6H), 1.29 (m, 32H), 1.47 (m, 4H), 1.82 (m,
4H), 3.89 (s, 3H), 4.01 (m, 4H), 5.22 (s, 2H), 5.26 (s, 2H), 6.95–7.00
(overlapped m, 5H), 7.45–7.57 (overlapped m, 12H), 7.66 (d, J=8.5 Hz,
1H), 7.70 ppm (s, 1H); 13C NMR (500 MHz, CDCl3, 258C, TMS): d=
14.3, 22.9, 26.3, 29.5, 29.6, 29.8, 29.9, 32.1, 51.1, 52.1, 68.3, 71.0, 71.4,
113.7, 115.0, 116.0, 123.4, 124.3, 127.0, 127.0, 127.8, 128.1, 128.2, 133.2,
133.3, 135.0, 135.3, 140.8, 140.8, 148.7, 153.2, 159.1, 165.4, 166.7,
167.0 ppm; elemental analysis calcd (%) for C58H76O6: C 80.14, H 8.81;
found: C 79.86, H 8.66.
gassed. Compound
2 (133 mg, 0.54 mmol) and denrdon 8 (810 mg,
1.09 mmol) were added. The reaction mixture was heated to 908C under
Ar for 15 h; it was then allowed to cool to 258C, was poured into water
(150 mL), and was extracted with CH2Cl2 (2”100 mL) and CHCl3 (2”
100 mL). The organic extracts were washed with water (100 mL), concen-
trated, and precipitated with MeOH. The precipitate was filtered, dried,
and purified by column chromatography (SiO2, CH2Cl2) to yield a color-
less solid (0.65 g, 69%). Purity (HPLC): 99+ %; Rf =0.50 (CH2Cl2);
1H NMR (500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=6.3Hz, 12H),
1.27 (m, 64H), 1.43(m, 8H), 1.79 (m, 8H), 3.96 (overlapped m, 11H),
5.11 (s, 4H), 5.13(s, 4H), 5.14 (s, 4H), 6.70 (t, J=2.2 Hz, 1H), 6.89 (m,
10H), 7.01 (d, J=8.4 Hz, 2H), 7.12 (d, J=8.4 Hz, 2H), 7.20 (s, 2H), 7.36
(m, 8H), 7.48 (d, J=8.2 Hz, 2H), 7.53(d, J=8.2 Hz, 2H), 7.64 (d, J=
8.3Hz, 2H), 8.10 ppm (d, J=8.3Hz, 2H); 13C NMR (500 MHz, CDCl3,
258C, TMS): d=14.5, 23.1, 26.5, 29.7, 29.8, 30.0, 30.1, 32.3, 68.5, 71.8,
72.0, 94.7, 97.6, 107.3, 114.9, 127.5, 128.4, 129.4, 129.6, 130.5, 135.6, 137.3,
141.2, 149.4, 149.8, 159.4, 160.8, 164.8 ppm; MS (MALDI-TOF): m/z
calcd for C116H152O12: 1737.1; found: 1777.6 [M+K]+; elemental analysis
calcd (%) for C128H160O12: C 81.32, H 8.53; found: C 81.11, H 8.39.
A
[(4Bp-
3,4)12G1-CH2OH] (14): Dendron 13 (2.80 g, 3.22 mmol) was added into
a suspension of LiAlH4 (0.25 g, 6.44 mmol) in THF (100 mL). The reac-
tion mixture was stirred at 258C for 3h, quenched by addition of water
and 15% (w/v) NaOH, filtered through Celite, concentrated, and precipi-
tated with MeOH. The precipitate was filtered. The product (2.54 g,
93%) was obtained by recrystallization from acetone. Purity (HPLC):
99+ %; Rf =0.50 (CHCl3); 1H NMR (500 MHz, CDCl3, 258C, TMS): d=
0.89 (t, J=6.3Hz, 6H), 1.29 (m, 32H), 1.47 (m, 4H), 1.82 (m, 4H), 4.01
(t, J=6.5 Hz, 4H), 4.60 (d, J=6.6 Hz, 2H), 5.20 (s, 2H), 5.21 (s, 2H),
6.89 (d, J=7.1 Hz, 1H), 6.97 (m, 5H), 7.05 (d, J=1.8 Hz, 1H), 7.46–
7.56 ppm (overlapped m, 12H); 13C NMR (500 MHz, CDCl3, 258C,
TMS): d=0.89 14.5, 23.1, 26.5, 29.8, 29.8, 30.0, 30.1, 32.3, 65.7, 68.6, 71.6,
71.8, 114.7, 115.2, 115.9, 120.7, 127.2, 128.2, 128.3, 128.5, 133.5, 134.9,
3’,5’-Bis[3’,4’-bis(4’-dodecyloxybiphenyl-4-ylmethoxy)benzyloxy]biphenyl-
4-carboxylate [(4Bp-3,4-3,5Bp)12G2-CO2CH3] (18):
A suspension of
K2CO3 (48 mg, 0.348 mmol) in DMF (30 mL) was thoroughly degassed.
Compound 2 (28 mg, 0.116 mmol) and dendron 15 (200 mg, 0.233 mmol)
were added. The reaction mixture was heated to 908C under Ar for 20 h;
it was then allowed to cool to 258C, was poured into water (100 mL),
and was extracted with CH2Cl2 (4”150 mL). The organic extracts were
washed with water (100 mL), concentrated, and precipitated with MeOH.
The precipitate was filtered, dried, and purified by column chromatogra-
4004
www.chemeurj.org
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2007, 13, 3989 – 4007

Dendrimers
FULL PAPER
phy (SiO2, CHCl3) to yield a colorless solid (156 mg, 72%). Purity
(HPLC): 99+ %; Rf =0.15 (CHCl3); 1H NMR (500 MHz, CDCl3, 258C,
TMS): d=0.89 (t, J=6.3Hz, 12H), 1.27 (m, 64H), 1.43(m, 8H), 1.79 (m,
8H), 3.94 (s, 3H), 4.00 (m, 8H), 4.99 (s, 4H), 5.20 (s, 8H), 6.62 (t, J=
2.2 Hz, 1H), 6.83(m, 2H), 6.90–7.00 (overlapped m, 12H), 7.10 (m, 2H),
7.45–7.55 (overlapped m, 24H), 7.60 (d, J=8.2 Hz, 2H), 8.08 ppm (d, J=
8.2 Hz, 2H); 13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.4, 22.9,
26.3, 29.6, 29.7, 29.8, 29.9, 32.2, 52.3, 68.4, 70.4, 71.5, 101.9, 107.1, 115.1,
115.5, 121.3, 127.0, 127.3, 128.0, 128.1, 128.3, 129.4, 130.3, 133.3, 135.7,
135.8, 140.7, 145.7, 149.3, 149.5, 159.0, 160.5 ppm; MS (MALDI-TOF): m/z
calcd for C128H160O12: 1889.2; found: 1912.1 [M+Na]+; elemental analysis
calcd (%) for C134H164O12: C 81.83, H 8.40; found: C 81.60, H 8.22.
J=2.2 Hz, 1H), 6.84 (d, J=2.2 Hz, 2H), 6.88–6.97 (overlapped m, 20H),
7.07 (s, 2H), 7.30–7.36 (overlapped m, 16H), 7.62 (d, J=8.3Hz, 2H),
8.09 ppm (d, J=8.3Hz, 2H); 13C NMR (500 MHz, CDCl3, 258C, TMS):
d=14.3, 22.9, 26.3, 29.5, 29.6, 29.7, 29.8, 29.9, 32.2, 52.3, 68.3, 70.2, 70.4,
71.5, 102.0, 107.1, 114.8, 115.1, 115.3, 115.7, 121.2, 127.3 129.0, 129.2,
129.3, 129.4, 129.7, 129.8, 130.2, 130.3, 142.4, 145.7, 149.3, 149.6, 158.9,
159.3, 160.6, 167.1 ppm; MS (MALDI-TOF): m/z calcd for C132H168O16
:
2009.2; found: 2032.1 [M+Na]+; elemental analysis calcd (%) for
C132H168O16: C 78.85, H 8.42; found: C 78.58, H 8.19.
Methyl 3,5-bis(4-{4-
ACHTREUNG
y}benzyloxy)biphenyl-4’-carboxylate
(27): A suspension of K2CO3 (34 mg, 0.243 mmol) in DMF (10 mL) was
thoroughly degassed. Compound 2 (20 mg, 0.081 mmol) and dendron 26
(150 mg, 0.163mmol) were added. The reaction mixture was heated to
908C under Ar for 15 h; it was then allowed to cool to 258C, was poured
into water (50 mL), and was extracted with CH2Cl2 (5”50 mL). The or-
ganic extracts were washed with water (100 mL), concentrated, and pre-
cipitated by MeOH. The precipitate was filtered, dried, and purified by
column chromatography (SiO2, CH2Cl2/hexane 10:1) to yield a colorless
solid (100 mg, 61%). Purity (HPLC): 99+ %; Rf =0.60 (CH2Cl2);
1H NMR (500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=6.3Hz, 12H),
1.27 (m, 64H), 1.43(m, 8H), 1.79 (m, 8H), 3.95 (overlapped m, 11H),
4.95 (s, 4H), 5.01 (s, 4H), 5.03(s, 4H), 5.07 (s, 8H), 6.65 (t, J=2.2 Hz,
1H), 6.85 (d, J=2.2 Hz, 2H), 6.88 (d, J=8.5 Hz, 8H), 6.93(s, 4H), 6.96
(d, J=8.7 Hz, 4H), 7.00 (d, J=8.7 Hz, 2H), 7.05 (s, 2H), 7.31–7.39 (over-
lapped m, 16H), 7.62 (d, J=8.3Hz, 2H), 8.09 ppm (d, J=8.3Hz, 2H);
13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.5, 23.1, 26.5, 29.7, 29.8,
29.9, 30.0, 30.1, 32.4, 52.5, 68.5, 70.3, 70.4, 70.5, 71.7, 96.2, 107.2, 114.9,
115.4, 115.8, 121.3, 127.5, 129.4, 129.5, 129.6, 129.7, 130.5, 137.0, 149.4,
149.7, 159.1, 159.3, 160.8 ppm; MS (MALDI-TOF): m/z calcd for
Methyl 3’,5’-bis[3’,4’-bis(4’-dodecyloxybiphenyl-4-ylmethoxy)biphenyl-4-
ylmethoxy]biphenyl-4-carboxylate [(4Bp-3,4Bp-3,5)12G2-CO2CH3] (20):
A suspension of K2CO3 (134 mg, 0.972 mmol) in DMF (50 mL) was thor-
oughly degassed. Compound 9 (27 mg, 0.162 mmol) and dendron 19
(330 mg, 0.328 mmol) were added. The reaction mixture was heated to
808C under Ar for 24 h; it was then allowed to cool to 258C and was
poured into water (300 mL). The precipitate was filtered, dried, and puri-
fied by column chromatography (SiO2, CHCl3) to yield a colorless solid
(200 mg, 62%). Purity (HPLC): 99+ %; Rf =0.90 (CHCl3); 1H NMR
(500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=6.3Hz, 12H), 1.27 (m,
64H), 1.43(m, 8H), 1.79 (m, 8H), 3.92 (s, 3H), 4.00 (m, 8H), 5.11 (s,
4H), 5.24 (s, 4H), 5.26 (s, 4H), 6.84 (t, J=2.2 Hz, 1H), 6.96 (m, 8H),
7.05 (d, J=8.4 Hz, 2H), 7.14 (d, J=8.4, 2H), 7.25 (d, J=2.1 Hz, 2H),
7.33 (d, J=2.3Hz, 2H), 7.44–7.60 ppm (overlapped m, 32H); 13C NMR
(500 MHz, CDCl3, 258C, TMS): d=14.3, 22.9, 26.3, 29.6, 29.7, 29.9, 32.2,
52.5, 68.4, 70.4, 71.6, 71.8, 107.6, 108.8, 114.9, 115.1, 115.8, 120.6, 127.0,
127.3, 128.1, 128.2, 128.3, 132.4, 133.4, 134.7, 135.3, 135.8, 140.7, 140.8,
141.0, 149.2, 149.6, 159.1, 160.1, 167.0 ppm; MS (MALDI-TOF): m/z
calcd for C134H164O12: 1965.2; found: 1988.4 [M+Na]+; elemental analysis
calcd (%) for C134H164O12: C 81.83, H 8.40; found: C 81.60, H 8.22.
C
132H168O16: 2009.2; found: 2048.1 [M+K]+.
Methyl 3,5-bis{4-[3,4-bis(4-dodecyloxybenzyloxy)benzyloxy]benzyloxy}bi-
AHCTREUNG
Methyl 3,5-bis(4-
y}benzyloxy)biphenyl-4’-carboxylate
G
phenyl-4’-carboxylate [(4-3,4-4-3,5Bp)12G2-CO2CH3] (29): A suspension
of K2CO3 (0.50 g, 3.64 mmol) in DMF (50 mL) was thoroughly degassed
and heated to 508C. Compound 2 (0.30 g, 1.21 mmol) and dendron 28
(1.98 mg, 2.43mmol) were added. The reaction mixture was heated to
908C under Ar for 15 h; it was then allowed to cool to 258C, was poured
into water (300 mL), and was extracted with CH2Cl2 (3”250 mL) and
with CHCl3 (2”200 mL). The organic extracts were washed with water
(100 mL), concentrated, and precipitated by MeOH. The precipitate was
filtered, dried, and purified by column chromatography (SiO2, CH2Cl2/
hexane 5:1) to yield a colorless solid (1.83g, 84%). Purity (HPLC): 99 +
%; Rf =0.65 (CH2Cl2/hexane 5:1); 1H NMR (500 MHz, CDCl3, 258C,
TMS): d=0.89 (t, J=6.3Hz, 12H), 1.27 (m, 64H), 1.43(m, 8H), 1.79 (m,
8H), 3.95 (overlapped m, 11H), 4.96 (s, 4H), 5.03 (s, 4H), 5.07 (s, 8H),
6.65 (t, J=2.2 Hz, 1H), 6.85 (d, J=2.2 Hz, 2H), 6.87 (d, J=8.1 Hz, 8H),
6.94 (s, 2H), 6.98 (d, J=8.6 Hz, 4H), 7.05 (s, 2H), 7.31–7.38 (overlapped
m, 14H), 7.63(d, J=8.4 Hz, 2H), 8.09 ppm (d, J=8.4 Hz, 2H); 13C NMR
(500 MHz, CDCl3, 258C, TMS): d=14.3, 22.9, 26.3, 29.6, 29.7, 29.8, 29.9,
32.2, 52.3, 68.3, 70.3, 71.6, 101.9, 107.0, 114.7, 115.3, 115.7, 121.1, 127.3,
129.2, 129.3, 129.4, 129.5, 130.3, 142.4, 145.8, 149.3, 149.6, 159.0, 159.2,
160.6, 167.2 ppm; MS (MALDI-TOF): m/z calcd for C118H156O14: 1797.1;
found: 1820.7 [M+Na]+; elemental analysis calcd (%) C132H168O16: C
78.80, H 8.74; found: C 78.60, H 8.16.
(23): A suspension of K2CO3 (96 mg, 0.696 mmol) in DMF (20 mL) was
thoroughly degassed. Compound 2 (28 mg, 0.116 mmol) and dendron 22
(240 mg, 0.236 mmol) were added. The reaction mixture was heated to
908C under Ar for 20 h; it was then allowed to cool to 258C, was poured
into water (60 mL), and was extracted with CH2Cl2 (3”70 mL). The or-
ganic extracts were washed with water (50 mL), concentrated, and pre-
cipitated with MeOH. The precipitate was filtered, dried, and purified by
column chromatography (SiO2, CH2Cl2) to yield
a colorless solid
(195 mg, 76%). Purity (HPLC): 99+ %; Rf =0.60 (CH2Cl2); 1H NMR
(500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=6.3Hz, 12H), 1.27 (m,
64H), 1.43(m, 8H), 1.79 (m, 8H), 3.94 (overlapped m, 11H), 4.96 (s,
4H), 4.98 (s, 8H), 5.02 (s, 4H), 5.07 (s, 8H), 6.65 (t, J=2.0 Hz, 1H), 6.85
(d, J=2.2 Hz, 2H), 6.88–7.00 (overlapped m, 24H), 7.05 (s, 2H), 7.31–
7.37 (overlapped m, 20H), 7.62 (d, J=8.6 Hz, 2H), 8.08 ppm (d, J=
8.6 Hz, 2H); 13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.4, 22.9,
26.3, 29.5, 29.6, 29.7, 29.8, 29.9, 32.2, 68.3, 70.2, 70.3, 71.5, 71.6, 114.9,
115.1, 115.3, 121.1, 127.3, 129.0, 129.2, 129.4, 129.5, 129.7, 129.8, 130.3,
149.3,149.6, 158.9, 159.3, 167.0 ppm; MS (MALDI-TOF): m/z calcd for
C
146H180O18: 2221.3; found: 2245.3 [ M+Na]+; elemental analysis calcd
(%) for C146H180O18: C 78.88, H 8.16; found: C 78.63, H 8.09.
Methyl 3,5-bis
C
3,5-Bis{4-
[(4-3,4-4-3,5Bp)12G2-H] (30):
ACHTREUNG
A
sion of K2CO3 (124 mg, 0.897 mmol) in DMF (25 mL) was thoroughly de-
0.551 mmol) in DMF (20 mL) was thoroughly degassed. Compound 21
(35 mg, 0.188 mmol) and dendron 28 (306 mg, 0.376 mmol) were added.
The reaction mixture was heated to 808C under Ar for 15 h; it was then
allowed to cool to 258C, was poured into water (300 mL), and was ex-
tracted with CH2Cl2 (3”50 mL). The organic extracts were washed with
water (100 mL), concentrated, and precipitated by MeOH. The precipi-
tate was filtered, dried, and purified by column chromatography (SiO2,
CH2Cl2) to yield a colorless solid (230 mg, 70%). Purity (HPLC): 99+
%; Rf =0.20 (CH2Cl2); 1H NMR (500 MHz, CDCl3, 258C, TMS): d=0.89
(t, J=6.3Hz, 12H), 1.27 (m, 64H), 1.43(m, 8H), 1.79 (m, 8H), 3.96 (t,
J=6.6 Hz, 8H), 4.96 (s, 4H), 5.03(s, 4H), 5.07 (s, 8H), 6.62 (t, J=2.4 Hz,
1H), 6.83(d, J=2.3Hz, 2H), 6.88 (d, J=8.1 Hz, 8H), 6.94 (s, 4H), 6.98
gassed. Compound
2 (73mg, 0.299 mmol) and dendron 24 (550 mg,
0.598 mmol) were added. The reaction mixture was heated to 908C under
Ar for 12 h; it was then allowed to cool to 258C, was poured into of
water (100 mL), and was extracted with CH2Cl2 (5”150 mL) and with
CHCl3 (150 mL). The organic extracts were washed with water (100 mL),
concentrated, and precipitated with MeOH. The precipitate was filtered,
dried, and purified by column chromatography (SiO2, CH2Cl2) to yield a
colorless solid (410 mg, 68%). Purity (HPLC): 99+ %; Rf =0.50
(CH2Cl2); 1H NMR (500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=
6.3Hz, 12H), 1.27 (m, 64H), 1.43(m, 8H), 1.79 (m, 8H), 3.95 (overlap-
ped m, 11H), 4.95 (s, 4H), 4.98 (s, 4H), 4.99 (s, 4H), 5.07 (s, 8H), 6.62 (t,
Chem. Eur. J. 2007, 13, 3989 – 4007
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
4005

V. Percec et al.
(d, J=8.6 Hz, 4H), 7.05 (s, 2H), 7.31–7.38 (overlapped m, 15H),
7.57 ppm (d, J=8.4 Hz, 2H); 13C NMR (500 MHz, CDCl3, 258C, TMS):
d=14.4, 22.9, 26.3, 29.5, 29.6, 29.7, 29.9, 32.2, 32.5, 68.3, 70.2, 70.3, 71.5,
71.6, 101.2, 106.8, 114.7, 115.2, 115.3, 115.7, 121.1, 127.4, 128.9, 129.2,
129.3, 129.5, 130.3, 149.2, 149.5, 159.1, 160.5 ppm; MS (MALDI-TOF):
m/z calcd for C116H154O12: 1739.1; found: 1763.2 [M+Na]+.
8H), 3.45 (s, 3H), 3.76 (t, J=4.2 Hz, 2H), 3.95 (t, J=4.3Hz, 8H), 4.51 (t,
J=4.2 Hz, 2H), 4.96 (s, 4H), 5.03(s, 4H), 5.07 (s, 8H), 6.65 (m, 1H),
6.85 (d, J=8.2 Hz, 2H), 6.87 (d, J=8.1 Hz, 8H), 6.94 (s, 4H), 6.98 (d, J=
8.6 Hz, 4H), 7.05 (s, 2H), 7.32–7.37 (overlapped m, 12H), 7.62 (d, J=
8.4 Hz, 2H), 8.12 ppm (d, J=8.4 Hz, 2H); 13C NMR (500 MHz, CDCl3,
258C, TMS): d=14.3, 22.9, 26.3, 29.6, 29.7, 29.8, 29.9, 32.2, 52.3, 58.8,
63.8, 68.3, 70.4, 71.6, 101.9, 107.0, 115.3, 115.7, 121.1, 127.3, 129.3, 129.4,
130.3, 142.4, 145.8, 149.3, 149.6, 159.0, 159.2, 160.6, 167.2 ppm; MS
A
N
yl-4’-yl} methanol [(4-3,4-4-3,5Bp)12G2-CH2OH] (31): Dendron 29
(200 g, 0.111 mmol) was added into suspension of LiAlH4 (13mg,
0.333 mmol) in THF (5 mL). The reaction mixture was stirred at 258C
for 1 h, quenched by addition of water and 15% (w/v) NaOH, filtered
through Celite, concentrated, and precipitated with MeOH. The precipi-
tate was filtered and a colorless solid was obtained (180 g, 90%). Purity
(HPLC): 99+ %; Rf =0.50 (CH2Cl2); 1H NMR (500 MHz, CDCl3, 258C,
TMS): d=0.89 (t, J=6.3Hz, 12H), 1.27 (m, 64H), 1.43(m, 8H), 1.79 (m,
8H), 3.95 (m, 8H), 4.74 (d, J=5.8 Hz, 2H), 4.96 (s, 4H), 5.02 (s, 4H),
5.07 (s, 8H), 6.62 (t, J=2.2 Hz, 1H), 6.82 (d, J=2.2 Hz, 2H), 6.88 (d, J=
8.1 Hz, 8H), 6.94 (s, 4H), 6.98 (d, J=8.6 Hz, 4H), 7.05 (s, 2H), 7.31–7.38
(overlapped m, 12H), 7.43(d, J=7.9 Hz, 2H), 7.55 ppm (d, J=7.9 Hz,
2H); 13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.6, 23.1, 26.5, 29.2,
29.5, 29.6, 29.7, 29.8, 29.9, 30.0, 30.1, 30.2, 31.9, 32.4, 65.5, 68.5, 70.4, 71.7,
71.8, 101.4, 107.0, 114.9, 115.4, 115.5, 115.9, 121.3, 127.7, 127.8, 129.4,
129.5, 129.5, 129.7, 130.5, 140.6, 140.9, 143.4, 149.4, 149.7, 159.2, 159.3,
160.7 ppm; MS (MALDI-TOF): m/z calcd for C117H156O13: 1765.1; found:
1792.8 [M+Na]+; elemental analysis calcd (%) for C132H168O16: C 78.80,
H 8.74; found: C 78.60, H 8.16.
(MALDI-TOF): m/z calcd for
[M+Na]+.
C120H160O15: 1841.2; found: 1864.9
3,5-Bis{4-[3,4-bis(4-dodecyloxy-benzyloxy)benzyloxy]benzyloxy}biphenyl-
A
4-carboxylic acid amide [(4-3,4-4-3,5Bp)12G2-CONH2] (35): Dendron 32
(200 mg, 0.110 mmol) and DTBMP (22 mg, 0.110 mmol) were dissolved
in dry CH2Cl2 (5 mL). SOCl2 (12 mL, 0.165) dissolved in dry CH2Cl2
(0.5 mL). The reaction mixture was stirred for 2 h. NH3(g) was bubbled
through the reaction mixture for 5 min. The reaction mixture was then
stirred at 258C for another hour, concentrated, and precipitated with
MeOH. The precipitate was purified by column chromatography (basic
alumina, CH2Cl2/MeOH 15:1). Recrystallization from acetone yielded a
colorless solid (123mg, 61%). Purity (HPLC): 99 +; Rf =0.80 (CH2Cl2/
MeOH 15:1); 1H NMR (500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=
6.3Hz, 12H), 1.27 (m, 64H), 1.43 (m, 8H), 1.79 (m, 8H), 3.95 (t, J=
6.5 Hz, 8H), 4.98 (s, 4H), 5.04 (s, 4H), 5.05 (s, 4H), 5.06 (s, 4H), 5.79
(brs, 2H), 6.66 (t, J=2.1 Hz, 1H), 6.82 (d, J=2.1 Hz, 2H), 6.87 (d, J=
8.1 Hz, 8H), 6.94 (s, 4H), 6.98 (d, J=8.4 Hz, 4H), 7.06 (s, 2H), 7.31–7.38
(overlapped m, 12H), 7.59 (d, J=8.4 Hz, 2H), 7.85 ppm (d, J=8.4 Hz,
2H); 13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.4, 22.9, 26.3, 27.0,
29.5, 29.6, 29.7, 29.9, 32.3, 70.2, 70.3, 71.5, 101.8, 106.9, 108.3, 114.7, 115.1,
115.3, 115.6, 121.1, 124.6, 127.4, 127.5, 129.2, 129.3, 130.3, 146.6, 149.3,
149.5, 159.0, 159.2, 160.6, 164.6 ppm; MS (MALDI-TOF): m/z calcd for
Potassium 3,5-bis{4-[3,4-bis(4-dodecyloxybenzyloxy)benzyloxy]benzylox-
N
y}biphenyl-4’-carboxylate [(4-3,4-4-3,5Bp)12G2-CO2K] (32): Dendron 29
(2.10 g, 1.17 mmol) was dissolved in of THF/H2O mixture (20:1, 21 mL).
KOH (0.33 g, 5.84 mmol) was added. The reaction mixture was heated to
658C for 15 h, concentrated, and precipitated with MeOH. Filtration and
drying yielded a colorless solid (2.10 g, 100%). Purity (HPLC): 99+ %;
C
117H155NO12: 1782.1; found: 1806.8 [M+Na]+; elemental analysis calcd
(%) for C132H168O16: C 78.80, H 8.74; found: C 78.60, H 8.16).
3,5-Bis{4-[3,4-bis(4-dodecyloxybenzyloxy)benzyloxy]benzyloxy}biphenyl-
1
Rf =0.65 (CH2Cl2/MeOH 15:1); H NMR (500 MHz, CDCl3, 508C, TMS):
AHCTREUNG
d=0.89 (t, J=6.3Hz, 12H), 1.27 (m, 64H), 1.43(m, 8H), 1.79 (m, 8H),
3.96 (t, J=6.6 Hz, 8H), 4.83(s, 4H), 4.87 (s, 4H), 4.96 (s, 4H), 4.98 (s,
4H), 6.50 (s, 1H), 6.69 (s, 2H), 6.83(m, 8H), 6.90 (m, 8H), 7.04 (s, 2H),
7.25 (m, 8H), 7.35 (d, J=7.2 Hz, 2H), 7.92 ppm (d, J=7.0 Hz, 2H);
13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.4, 22.8, 26.4, 29.7, 29.8,
29.9, 32.2, 52.4, 68.1, 70.5, 71.7, 101.3, 106.9, 113.8, 115.0, 121.2, 127.3,
129.2, 129.3, 129.4, 129.5, 130.1, 142.1, 145.8, 149.3, 149.4, 159.0,
159.1 ppm.
4-carboxylic acid methylamide [(4-3,4-4-3,5Bp)12G2-CONHCH3] (36):
Dendron 32 (200 mg, 0.110 mmol), CDI (36 mg, 0.220 mmol), and DPTS
(7 mg, 0.022 mmol) were dissolved in dry CH2Cl2 (5 mL). The reaction
mixture was stirred at 258C for 2 h. Triethylamine (29 mg, 0.275 mmol)
and methylammonium chloride (19 mg, 0.275 mmol) were dissolved in
dry CH2Cl2 (1 mL) and added to reaction mixture. The reaction mixture
was stirred at 258C for 20 h to achieve 30% conversion by TLC. CDI
(71 mg, 0.440 mmol) and methylammonium chloride (30 mg, 0.440 mmol)
were added to reaction mixture. The reaction mixture was stirred at 258C
for another 24 h, concentrated, and precipitated with MeOH. A colorless
solid (125 mg, 62%) was obtained after recrystallization from acetone.
Purity (HPLC): 99+ %; Rf =0.90 (CH2Cl2/MeOH 15:1); 1H NMR
(500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=6.3Hz, 12H), 1.27 (m,
64H), 1.43(m, 8H), 1.79 (m, 8H), 3.95 (t, J=6.6 Hz, 8H), 4.97 (s, 4H),
5.03(s, 4H), 5.05 (s, 4H), 5.07 (s, 4H), 6.20 (2s, 2H), 6.65 (m, 1H), 6.81
(d, J=2.1 Hz, 2H), 6.87 (d, J=8.1 Hz, 8H), 6.93(s, 4H), 6.97 (d, J=
8.4 Hz, 4H), 7.05 (s, 2H), 7.31–7.38 (overlapped m, 12H), 7.56 (d, J=
8.4 Hz, 2H), 7.80 ppm (d, J=8.4 Hz, 2H); 13C NMR (500 MHz, CDCl3,
258C, TMS): d=14.4, 22.9, 26.3, 27.0, 29.5, 29.6, 29.7, 29.9, 32.2, 68.3,
70.2, 70.3, 71.5, 101.8, 106.9, 108.3, 110.7, 114.7, 115.1, 115.3, 115.6, 121.1,
124.6, 127.4, 127.5, 129.2, 129.3, 129.4, 130.3, 142.8, 146.6, 149.2, 149.5,
158.9, 159.2, 160.6, 164.6, 175.4 ppm; MS (MALDI-TOF): m/z calcd for
3,5-Bis{4-[3,4-bis(4-dodecyloxybenzyloxy)benzyloxy]benzyloxy}biphenyl-
N
4’-carboxylic acid [(4-3,4-4-3,5Bp)12G2-COOH] (33): Dendron 32
(150 mg, 0.082 mmol) was dissolved in THF (4 mL). Acetic acid (1 mL)
was added. The reaction mixture was stirred at 258C for 5 min and was
then precipitated with MeOH. The precipitate was filtered and recrystal-
lized from acetone to yield a colorless solid (120 mg, 80%). Purity
(HPLC): 99+ %; Rf =0.95 (CH2Cl2/MeOH 15:1); 1H NMR (500 MHz,
CDCl3, 258C, TMS): d=0.89 (t, J=6.3Hz, 12H), 1.27 (m, 64H), 1.43(m,
8H), 1.79 (m, 8H), 3.95 (overlapped m, 11H), 4.96 (s, 4H), 5.03 (s, 4H),
5.07 (s, 8H), 6.67 (s, 1H), 6.87 (d, J=2.2 Hz, 2H), 6.88 (d, J=8.1 Hz,
8H), 6.94 (s, 2H), 7.05 (d, J=8.6 Hz, 4H), 7.05 (s, 2H), 7.33–7.38 (over-
lapped m, 12H), 7.66 (d, J=8.4 Hz, 2H), 8.16 ppm (d, J=8.4 H, 2Hz);
13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.3, 22.8, 26.3, 29.6, 29.7,
29.9, 32.1, 52.2, 68.2, 70.4, 71.6, 101.7, 107.0, 114.0, 115.3,121.2, 127.3,
129.3, 129.3, 129.5, 129.6, 130.3, 142.3, 145.9, 149.3, 149.6, 159.0, 159.2,
160.6 ppm; MS (MALDI-TOF): m/z calcd for C117H154O14: 1783.1; found:
1822.9 [M+K]+.
C
118H157NO13: 1796.2; found: 1818.9 [M+Na]+.
(S)-3,5-Bis{4-[3,4-bis(4-dodecyloxybenzyloxy)benzyloxy]benzyloxy}bi-
phenyl-4-carboxylic acid sec-butylamide [(S)-(4-3,4-4-3,5Bp)12G2-
CONHCH(CH3)C2H5] (37): Dendron 32 (400 mg, 0.219 mmol) and
AHCTREUNG
AHCTREUNG
2-Methoxy-ethyl
benzyloxy}biphenyl-4’-carboxylate
(CH2)2OCH3] (34): Dendron 32 (200 mg, 0.110 mmol), 2-methoxy-etha-
3,5-bis{4-
ACHTREUNG
DTBMP (67 mg, 0.329 mmol) were dissolved in dry CH2Cl2 (5 mL).
DMF (1 drop) and SOCl2 (52 mg, 0.437 mmol) were added to reaction
mixture, which was then stirred at 258C under Ar for 2 h; (S)-sec-butyla-
mine (192 mg, 2.625 mmol) was then added. The reaction mixture was
stirred at 258C under Ar for a further 15 h, was concentrated by heating
to 508C, and was precipitated with MeOH. Column chromatography
(Al2O3, CH2Cl2/acetone 20:1) yielded a colorless solid (260 mg, 65%).
Purity (HPLC): 99+ %; Rf =0.80 (CH2Cl2/MeOH 15:1); 1H NMR
(500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=6.2 Hz, 12H), 0.99 (t, J=
ACHTREUNG
nol (17 mg, 0.220 mmol), DCC (34 mg, 0.165 mmol), and DPTS (32 mg,
0.110 mol) were dissolved in dry CH2Cl2 (5 mL) under Ar. The reaction
mixture was stirred at 258C for 5 h, concentrated, and purified by column
chromatography (SiO2, CH2Cl2/methanol 25:1). Recrystallization from
acetone yielded a colorless solid (175 mg, 87%). Purity (HPLC): 99+ %;
Rf =0.90 (CH2Cl2/methanol 25:1); 1H NMR (500 MHz, CDCl3, 258C,
TMS): d=0.89 (t, J=6.3Hz, 12H), 1.27 (m, 64H), 1.43(m, 8H), 1.79 (m,
4006
www.chemeurj.org
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2007, 13, 3989 – 4007

Dendrimers
FULL PAPER
7.2 Hz, 3H), 1.27 (m, 66H), 1.43 (m, 8H), 1.52 (m, 2H), 1.79 (m, 8H),
3.95 (t, J=4.3Hz, 8H), 4.17 (m, 1H), 4.96 (s, 4H), 5.02 (s, 4H), 5.07 (s,
8H), 5.88 (d, J=5.3Hz, 2H), 6.64 (t, J=2.2 Hz, 1H), 6.85 (s, 2H), 6.87
(d, J=8.1 Hz, 8H), 6.94 (s, 4H), 6.98 (d, J=8.6 Hz, 4H), 7.05 (s, 2H),
7.32–7.37 (overlapped m, 12H), 7.62 (d, 2H, J=8.4 Hz), 7.81 ppm (d, J=
8.4 Hz, 2H); 13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.3, 20.8,
22.8, 26.3, 29.4, 29.9, 30.0, 30.1, 32.1, 47.2, 68.2, 70.3, 71.5, 114.8, 115.1,
115.2, 115.4, 115.5, 115.6, 121.2, 127.5, 127.6, 129.3, 129.6, 130.1, 158.9,
Mayer, S. C. Zimmerman, Angew. Chem. 2003, 115, 1153–1158;
Angew. Chem. Int. Ed. 2003, 42, 1121–1126; j) S. Hecht, A. Khan,
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42, 6021–6024; k) S. Rosselli, A.-D. Ramminger, T. Wagner, B.
Silier, S. Wiegand, W. Hꢂussler, G. Lieser, V. Scheumann, S. Hçger,
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159.1, 159.2 ppm; MS (MALDI-TOF): m/z calcd for C121H163NO13
:
1838.2; found: 1861.4 [M+Na]+.
(R)-3,5-Bis{4-
phenyl-4-carboxylic acid sec-butylamide [(R)-(4-3,4-4-3,5Bp)12G2-
CONHCH(CH3)C2H5] (38): Dendron 32 (400 mg, 0.219 mmol) and
A
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ACHTREUNG
DTBMP (67 mg, 0.329 mmol) were dissolved in dry CH2Cl2 (5 mL).
DMF (1 drop) and SOCl2 (52 mg, 0.437 mmol) were added to reaction
mixture, which was then stirred at 258C under Ar for 3h; then ( R)-sec-
butylamine (192 mg, 2.625 mmol) was added. The reaction mixture was
stirred at 258C under Ar for a further 20 h, was concentrated by heating
to 508C, and was precipitated with MeOH. Column chromatography
(Al2O3, CH2Cl2/acetone 20:1) yielded a colorless solid (280 mg, 70%).
Purity (HPLC): 99+ %; Rf =0.80 (CH2Cl2/MeOH 15:1); 1H NMR
(500 MHz, CDCl3, 258C, TMS): d=0.89 (t, J=6.2 Hz, 12H), 1.00 (t, J=
7.1 Hz, 3H), 1.27 (m, 66H), 1.43 (m, 8H), 1.52 (m, 2H), 1.79 (m, 8H),
3.95 (t, J=4.3Hz, 8H), 4.18 (m, 1H), 4.96 (s, 4H), 5.02 (s, 4H), 5.06 (s,
8H), 5.80 (d, J=5.2 Hz, 2H), 6.64 (t, J=2.2 Hz, 1H), 6.85 (s, 2H), 6.87
(d, J=8.1 Hz, 8H), 6.95 (s, 4H), 7.00 (d, J=8.6 Hz, 4H), 7.05 (s, 2H),
7.31–7.36 (overlapped m, 12H), 7.63 (d, J=8.4 Hz, 2H), 7.82 ppm (d, J=
8.4 Hz, 2H). 13C NMR (500 MHz, CDCl3, 258C, TMS): d=14.3, 20.8,
22.9, 26.3, 29.5, 29.6, 29.8, 29.9, 30.0, 32.1, 47.3, 68.3, 70.2, 71.5, 114.7,
115.2, 115.3, 115.6, 115.7, 121.1, 127.4, 127.5, 129.3, 129.5, 130.2, 159.0,
159.1 ppm; MS (MALDI-TOF): m/z calcd for C121H163NO13
: 1838.2;
found: 1862.1 [M+Na]+.
Acknowledgements
Financial support by the National Science Foundation (DMR-0548559)
and the Office of Navel Research is greatly appreciated. J.S. acknowledg-
es an Isabel and Alfred Bader graduate fellowship and S.N. the National
Technology Agency of Finland (TEKES) and the Ellen and Artturi Nyys-
sçnen Foundation.
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Received: November 6, 2006
Published online: February 16, 2007
Chem. Eur. J. 2007, 13, 3989 – 4007
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