Synthesis and solid-state organization of coil-ring-coil block copolymers

Article abstract of DOI:10.1002/chem.200304796

Shape-persistent macrocycles based on the phenyl-ethynyl-butadienyl backbone containing two extraannular hydroxyl groups were prepared by the oxidative coupling of the appropriate phenylethynyl oligomers. Carbodiimide-directed coupling with independently synthesized polystyrene carboxylic acid oligomers led to ABA coil-ring-coil block copolymers in which the central macrocycle serves as rigid and the polystyrene oligomers as flexible elements. Depending on the size of the coil blocks, these structures aggregate in cyclohexane into supramolecular hollow cylindrical brushes in which the rigid core is surrounded by the flexible matrix. However, in the solid state it is not possible to identify a morphology in which isolated channels based on aggregated macrocycles are embedded in a matrix of polystyrene. Detailed X-ray and electron diffraction studies on samples prepared from a solution in cyclohexane under equilibrium conditions show that the material adopts a lamellar morphology in the solid state in which columns of macrocycles are aggregated into layers which are separated by polystyrene.

Full text of DOI:10.1002/chem.200304796

G. Lieser, S. Hˆger et al.
Chem. Eur. J. 2003, 9, 3481 3491
DOI: 10.1002/chem.200304796
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3481

FULL PAPER
Synthesis and Solid-State Organization of
Coil Ring Coil Block Copolymers
Silvia Rosselli,[a] Anne-De¬sire¬e Ramminger,[a] Thomas Wagner,[a]
G¸nter Lieser,*[a] and Sigurd Hˆger*[a,b]
Dedicated to Professor Manfred T. Reetz on the occasion of his 60th birthday
Abstract: Shape-persistent macrocycles
based on the phenyl-ethynyl-butadienyl
backbone containing two extraannular
hydroxyl groups were prepared by the
oxidative coupling of the appropriate
phenylethynyl oligomers. Carbodiimide-
directed coupling withindependently
synthesized polystyrene carboxylic acid
oligomers led to ABA coil ring coil
block copolymers in which the central
macrocycle serves as rigid and the poly-
styrene oligomers as flexible elements.
Depending on the size of the coil blocks,
these structures aggregate in cyclohex-
ane into supramolecular hollow cylin-
drical brushes in which the rigid core is
surrounded by the flexible matrix. How-
ever, in the solid state it is not possible to
identify a morphology in which isolated
channels based on aggregated macro-
cycles are embedded in a matrix of
polystyrene. Detailed X-ray and elec-
tron diffraction studies on samples pre-
pared from a solution in cyclohexane
under equilibrium conditions show that
the material adopts a lamellar morphol-
ogy in the solid state in which columns of
macrocycles are aggregated into layers
which are separated by polystyrene.
Keywords:
nanostructures
macrocycles
polymers
¥
¥
¥
supramolecular chemistry
arising from the microphase separation of the rod and the coil
blocks.[1] The aggregation of the rigid segments into liquid-
crystalline domains that is observed even at relatively low
degrees of polymerization is a result of the high incompati-
bility of the different blocks. The kind of nanostructure that is
actually formed depends on the nature of the blocks, the total
molecular weight of the polymer and the volume fraction of
the rigid and the flexible blocks, respectively.[2]
Recently, we described a new class of rod coil block
copolymers in which the rigid segment is a nanometer-sized
shape-persistent macrocycle to which two polystyrene (PS)
blocks are covalently attached leading to coil ring coil
block copolymers (Figure 1).[3, 4]
Introduction
The understanding of the design principles for molecular
building blocks that can self-assemble into well-defined
structures is the basis for the construction of aggregates with
a high degree of complexity. In the field of polymer science,
the synthesis, investigation, and theoretical description of
block copolymers composed of two or more flexible blocks
that phase separate into a variety of morphologies has made
significant progress over the last decades. It is the basis for
many materials used today.
During the last decade, the aggregation behavior of block
copolymers in which at least one block is more or less rigid
and another is rather flexible (rod coil block copolymers)
has attracted increasing attention. This provides an oppor-
tunity for the formation of supramolecular nanostructures
[a] Prof.Dr. S. Hˆger, Dr. G. Lieser, Dr. S. Rosselli,
A.-D. Ramminger, T. Wagner
Figure 1. Schematic presentation of coil ring coil block copolymers.
Max Planck Institute for Polymer Research
Ackermannweg10, 55128 Mainz (Germany)
Fax : (‡49)6131-379-100
E-mail: lieser@mpip-mainz.mpg.de
Due to its structure, the rigid part of the molecule can no
longer be described as one-imensional but has a similar
expansion in the second dimension. In contrast to disklike
molecules, these noncollapsed macrocycles have a nanoscale
hollow interior that allows the arrangement of functional
[b] Prof.Dr. S. Hˆger,
New address: Universit‰t Karlsruhe
Polymer-Institut, Hertzstrasse16, 76187 Karlsruhe (Germany)
Fax : (‡49)721-608-4421
E-mail: hoeger@chemie.uni-karlsruhe.de.
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DOI: 10.1002/chem.200304796
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Coil Ring Coil Block Copolymers
3481 3491
groups in a convergent way.[5, 6] In addition, a columnar
arrangement of the macrocycles could lead to the formation
of supramolecular (intraannular functionalized) channel
structures.[7]
Owing to the attachment of the flexible side groups, the
solubility of the otherwise only moderately soluble rigid block
is largely enhanced. As reported previously, some of the coil
ring coil triblock copolymers 1 are even soluble in the non-
polar solvent cyclohexane, a V-solvent for polystyrene but not
for the rigid core.[8] Of course, the solubilizing influence of the
polystyrene block increases withincreasing molecular
weight.[9]
gated. With reference to ™hairy rod molecules∫, in which the
central rod is bound covalently, models of the aggregation
behavior could either be tubes of aggregated macrocycles
formed by the supramolecular cylindrical aggregates within a
polystyrene matrix (model 1, Figure 3a), or layered structures
of planar regular arrays of tubes interchanging with layers of
amorphous polystyrene (model 2, Figure 3b).[10] Predictions
as to which model better describes the aggregation behavior
cannot be made easily.
Here we describe the synthesis of 1 and the detailed
investigation of the solid-state structure of samples of 1c
prepared under equilibrium conditions.
Results and Discussion
Synthesis: Over the past several years we have prepared a
variety of different shape-persistent macrocycles based on the
phenyl-ethynyl-butadienyl backbone.[11] The cyclization reac-
tion is the CuI/CuII-mediated Glaser coupling of rather rigid
bisacetylenic precursors (™half-rings∫).[12] Their structure is
designed in sucha way taht teh coupling of only two
bisacetylenes gives the shape-persistent cyclic structure. This
is a compromise between the yield in the cyclization step and
the effort required in the preparation of the precursor. Their
preparation is routinely performed by a number of repetitive
Hagihara coupling and silyl-deprotecting steps of appropriate
monoprotected bisacetylenes. Synthesis of both the cycliza-
tion precursors and of the monoprotected bisacetylenes rely
on the combination of side selectivity in the palladium
catalyzed aryl acetylene coupling and the different depro-
tection kinetics of silyl groups of different bulk. Aromatic
bromoiodo compounds can first be selectively coupled with
terminal acetylenes at the iodo position. Subsequent addition
of a second acetylene will then lead to a coupling reaction at
the bromo position.[13] Furthermore, both coupling reactions
can be performed in a one-pot reaction to give unsymmetri-
cally substituted bisacetylenes in high yields. Since bisacety-
lenes protected with trimethylsilyl (TMS) or triethylsilyl
(TES) groups and triisopropylsilyl (TIPS) groups can be
selectively deprotected at the TMS or TES position, respec-
tively, monoprotected bisacetylenes are easily available from
bromoiodo compounds (Scheme 1).[14]
While 1e is easily soluble in cyclohexane and the solution
shows no unusual viscosity or birefringence, 1a in warm
cyclohexane forms only a suspension. Of special interest is 1c
(Mw of eachPS block ꢀ500 gmolÀ1) which dissolves well in
warm cyclohexane and upon cooling to room temperature
rapidly forms a very viscous solution. At the same time the
solution becomes strongly birefringent. These observations
were the starting point for a more detailed investigation into
solutions of 1c in cyclohexane. Scattering experiments in
solution as well as investigations on solid samples prepared
under ™nonequilibrium conditions∫ (i.e. by fast solvent
evaporation) revealed that the block copolymer aggregates
in solution into supramolecular hollow cylinderical brushes
withan external diameter of about 10 nm and a lumen of
about 2 nm. It can be assumed
Scheme 2 illustrates the synthesis of the half rings and their
cyclization. Bromo-4-iodobenzene (2) was treated withTES-
acetylene at room temperature overnight, and for an addi-
tional hour at 508C. Subsequently, a slight excess of 1-ethynyl-
3-(2-triisopropylsilylethynyl)-5-tert-butylbenzene[11a] was add-
that in solution the rigid core of
the brushes is isotropically sur-
rounded by the flexible PS co-
rona (Figure 2).
However, the solid-state
structure of samples of these
block copolymers prepared un-
der ™equilibrium conditions∫
(i.e. by slow solvent evapora-
tion) has not yet been investi- Figure 2. Aggregation of the coil ring coil block copolymers into hollow cylindrical brushes.
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G. Lieser, S. Hˆger et al.
FULL PAPER
Figure 3. Possible aggregation of the cylindrical brushes in the solid state.
yield after chromatography. The purity of the macrocycle was
determined by NMR spectroscopy and mass spectrometry as
well as by gel permeation chromatography (GPC), and
showed the absence of trimers and higher oligomers. As we
have explored previously, this elevated cyclization temper-
ature is a compromise between the increased coupling rate
favoring the dimer formation and the decreased product
stability.[15] Base-catalyzed hydrolysis of the benzoate groups
generated the macrocyclic diol 9.
The synthesis of the polystyrene carboxylic acid oligomer
(PS-COOH) 10 was done by anionic polymerization of
styrene in cyclohexane and subsequently adding the oligo-
styrene anion solution to a large excess of CO2-saturated
THF.[16] The oligomeric crude product could be purified
Scheme 1. Monoprotected bisacetylenes are prepared from the bromo-
iodo compounds.
ed, and the mixture was stirred for an additional four days at
the same temperature before workup. Deprotection of the
TES group of 3 was performed by stirring withpotassium
carbonate in methanol/THF (1:1) for four days. Palladium-
catalyzed coupling of 4 withthe diiodide 5, and desilylation of
6 by reaction withBu 4NF gave 7. CuCl/CuCl2-promoted
coupling of the half ring 7 was performed under pseudo-high-
dilution conditions at 558C and gave the macrocycle 8 in 50%
Scheme 2. a) 1. TES acetylene, Pd0 (cat.), CuI (cat.), piperidine; 2. ethynyl-3-(2-triisopropylsilylethynyl)-5-tert-butylbenzene, 91%; b) K2CO3, MeOH, THF,
83%; c) Pd0 (cat.), CuI (cat.), piperidine, 78%; d) Bu4NF, THF, 93%; e) CuCl, CuCl2, pyridine, 50%; f) KOH; H2O, THF, 87%; g) DMAP/p-TsOH,
diisopropyl carbodiimide, 32 86%.
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Coil Ring Coil Block Copolymers
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easily by column chromatography. Eluting with toluene
removed all side products (mostly PS and di-PS ketone) and
the PS-COOH was obtained by changing the eluent to
THF.
Attachment of the PS-COOH to the macrocyclic diol was
performed by the 4-dimethylaminopyridine (DMAP)/p-tol-
uenesulfonic acid (p-TsOH)-catalyzed carbodiimide coupling
overnight and purification of the crude reaction product by
column chromatography.[17] The coupling could also be
performed by esterification of 9 withthe corresponding PS-
carboxylic acid chloride or by reacting the macrocyclic diol
withPS-COOH using diethylazodicarboxylate (DEAD)/PPh
3
(Mitsunobu conditions) as condensating reagents. However,
in the first case the yield of the desired copolymer was very
low (according to the GPC data, about 10%) and we were not
able to purify the material by column chromatography or
precipitation. In the latter case the copolymer was formed in
high yields but the material contained an impurity with double
the molecular weight as observed by GPC. Again, pure ester 1
could not be obtained by simple column chromatography.
Various amounts of a side product of similar molecular weight
were also observed (GPC data) when an aqueous workup was
carried out on the reaction mixture of the DMAP/p-TsOH-
catalyzed carbodiimide coupling prior to the chromatographic
purification. The nature and the origin of this side product
could not be discovered. Nevertheless, changing the workup
procedure solved this problem. After the carbodiimide
coupling reaction was performed, the reaction solvent
(CH2Cl2) was removed under reduced pressure and the solid
residue chromatographed over silica gel. This operation
turned out to be essential and gave the block copolymers 1
in reproducible purity.
Figure 4. GPC and MALDI-TOF data of 1c.
All block copolymers 1 are readily soluble in chloroform,
dichloromethane, THF, and toluene and were characterized
by NMR spectroscopy, GPC, and matrix-assisted laser
desorption ionization time-of-flight spectroscopy (MALDI-
TOF). Figure 4 displays the GPC and MALDI-TOF data for
the block copolymer 1c. The distribution of molecular weights
is clearly a result of the anionic styrene polymerization and
the MALDI-TOF spectra show that even a polymer with a
polydispersity(PD) < 1.05 contains a variety of different
molecular species withmolecular weights ranging from 5500
up to 8000 gmolÀ1 in this case.
Solid-state organization: Despite the superstructure forma-
tion of 1c in cyclohexane, we were not able to observe the
formation of any superstructure by thermal treatment of this
material (i.e. slow or fast cooling from the melt). However, if
solid samples of 1c were prepared by slow evaporation of a
cyclohexane solution (i.e. under equilibrium conditions),
superstructure formation could be observed on different
length scales. Figure 5a shows the optical micrograph of a thin
film of 1c taken in differential interference contrast (DIC)
indicating the formation of a ribbon-like structure. Trans-
mission electron microscopy (TEM) studies could not extend
our knowledge significantly. They showed that these extended
moieties are composed of bundles of ribbons slightly tilted
round the predominant direction (Figure 5b). In particular,
an aggregation of supramolecular cylinders suchthat isolated
Figure 5. a) Optical micrographof ribbon-like structures of 1c imaged by
differential interference contrast in reflected light. b) Electron micrograph
of a similar sample (image taken at an electron energy loss of 235 eV for
enhanced contrast).
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G. Lieser, S. Hˆger et al.
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channels are formed within a PS matrix (Figure 3a, model 1)
could not be demonstrated by the TEM images.
Therefore, scattering experiments were conducted on
samples of 1c prepared under the same conditions (slow
solvent evaporation) to investigate the solid-state structure of
the material.
X-ray scattering of films (slow solvent evaporation) of 1c
performed in a powder diffractometer on a glass substrate
show very strong first- (n ˆ 1) and second-order (n ˆ 2)
reflections (Figure 6). Higher order reflections (n ˆ 4, 6, 10)
Figure 7. Electron diffraction pattern at perpendicular beam incidence.
Table 1. Observed and calculated reflections from X-ray data at room
temperature, electron diffraction data at T<À 508C.
h k l
dobs [ä]
dcalcd [ä]
h k l
dobs[b] [ä]
dcalcd [ä]
X-ray, powder diffraction
electron diffraction, 1st layer line
0 1 0
0 2 0
0 4 0
0 6 0
0.10.0
71.0
35.7
17.8
11.9
7.2
71.60
35.80
17.90
11.93
7.16
0 0 1
2 0 1
4 0 1
5 0 1
0 1 1
2 1 1
4 1 1
5 1 1
5 2 1
0 3 1
3 3 1
6 3 1
7 3 1
8 3 1
4 4 1
6 4 1
6.22
5.99
5.51
5.15
6.18
5.94
5.46
5.10
5.09
6.00
5.58
4.72
4.45
4.18
5.23
4.64
6.20
5.99
5.46
5.15
6.18
5.97
5.45
5.13
5.09
6.00
5.59
4.73
4.44
4.16
5.22
4.66
Figure 6. X-ray scattering of films of 1c (the intensity scale of the
scattering curve beyond 38 (right) is magnified by a factor of 5).
electron diffraction, equator
)
2 0 0
2 1 0
2 2 0
4 0 0
4 1 0
4 2 0
6 0 0
6 1 0
6 2 0
8 0 0
8 1 0
8 2 0
23.1
22.0
19.4
11.6
11.4
11.0
7.71
7.66
7.53
5.78
5.76
5.71
are present withmuchlower intensity as well as a diffuse
reflection originating from both the amorphous PS matrix and
the glass substrate. Because the scattering curve is recorded in
reflection the occurring reflections can be assigned to a
periodic lattice of layers oriented parallel to the substrate. The
layer distance determined from these reflections is d ˆ 71.6 ä.
Reflections for additional directions of beam incidence
were explored by complementary electron diffraction studies.
However, the proper preparation of the samples used for
electron diffraction turned out to be an essential task. During
the investigations it became evident that solvent was retained
in the samples and evaporated in the high vacuum of the
transmission electron microscope (TEM), a fact confirmed by
NMR spectroscopy (see below). The evaporating solvent left
a volume deficiency in the sample destroying any order in the
solid. Reproducible results were obtained only when the
samples were inserted into the high vacuum of the electron
microscope in a cryo-transfer holder at temperatures below
08C. The electron microscopic investigation was then carried
out at temperatures below À508C to avoid the escape of the
trapped solvent. With this technique a number of similar
electron diffraction patterns of samples cast from cyclohexane
could be obtained. As a common feature, an oriented set of
point reflections was observed, resembling on first sight fiber
diagrams consisting of an equator and a first layer line,
superimposed by a diffuse isotropic halo that originates from
the amorphous polystyrene. A typical diffraction pattern is
shown in Figure 7. In some cases additional reflections are
observed on a second layer line (Table 1).[18]
present[a]
present[a]
present[a]
present[a]
)
)
)
electron diffraction, 2nd layer line
0 2 2
0 3 2
0 5 2
3.08
3.07
3.03
3.09
3.07
3.03
[a] d spacings from reflections on the equator cannot be evaluated with
sufficient precision owing to superposition. [b] Average value of the data
taken from various diffraction patterns.
Although the reflections on the equator are less affected from
the superimposition by the amorphous halo their positions
cannot be measured withsufficient precision. Teh corre-
sponding data were therefore neglected for the data refine-
ment. Reflections on the layer lines are more distinct and
turned out to be appropriate for data evaluation.
For indexing the electron diffraction patterns it is assumed
that the reciprocal lattice vector a* is oriented along the
equator (ignoring an eventual superposition of several
adjacent reflections) and c* (equivalent to the repeat unit
along the oriented strands) along the meridian. In this system
of coordinates the X-ray reflections (Figure 6) have to be
indexed as 0k0. The predominant electron diffraction pattern
(Figure 7) therefore contains the h0l reflections. The sequence
of the reflections along a layer line point to a value in the
region of 45 ä for the a parameter. With this value in mind the
The meridian in the fiber-like diffraction patterns coincides
in all cases withteh axial direction of oriented strands
recognizable in the corresponding electron micrographs.
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Coil Ring Coil Block Copolymers
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innermost equatorial reflection is the 200 reflection. The
position of the maximum of intensity may vary by super-
imposition of adjacent reflections.[19] Close inspection of the
electron diffraction patterns, in particular of the sequence of
reflections along the ™layer lines∫, shows that the diffraction
patterns differ from fiber diagrams. They are diffraction
patterns of single crystals withsuperimpositions of a varying
number of reflections of adjacent zones.
The position of the first layer line varies between 5.9 and
6.2 ä corresponding to the prevailing index k for the meri-
dional reflection. The d spacings from the X-ray diffractogram
and from the reflections on the first and second layer in the
electron diffraction patterns were used in a least-squares
analysis to refine the lattice parameters (Table 1). The
observed reflections are compatible with an orthorhombic
cell withthe lattice constants
forms a lamellar morphology and that in solution the initially
formed supramolecular cylindrical brushes do not form
isolated channels within the amorphous PS matrix. The ability
of the block copolymers to form a lamellar superstructure is a
result of the attachment of the PS side chains at only two
positions of the ring.
As shown previously, the rings in adjacent stacks are tilted
with respect to each other so that herringbone packing is the
result. This tilt is remarkable with respect to the solid-state
structures of rod coil block copolymers. In a solvent,
preferential to the coil block, the aggregation block copoly-
mer can lead to a tilt of the rod blocks with respect to the
interface separating the rod and the coil blocks.[21] This gives
the coil blocks a larger area per junction to the rod blocks and
leads to reduced chain stretching of the coil blocks. At the
same time the interface between the rod and the coil block is
increased by the tilt so that the experimentally observed tilt
angle is a minimum of the energetic penalties associated with
chain stretching and interface separating (Figure 9a).[22]
In case of the coil ring coil block copolymers described
here, the tilt of the macrocycles with respect to the stack axis
does not give the coil blocks a larger area per junction to the
ring blocks. The increased separation of the junctions along
the stacking axis (c axis) is accompanied by a decreased
separation of the junction points along the a axis (Figure 9b).
Therefore, the tilt is dominated by the crystallization of the
rigid parts of the block copolymer that try to minimize the
a ˆ 46.1, b ˆ 71.6, c ˆ 6.2 ä, Z ˆ 2 (Vˆ 20465 ä3).
The d values calculated for the equatorial reflections show
that the observed maxima of intensity are superpositions of at
least three adjacent reflections with varying index k (and
unknown intensity ratio). With the assumption that the block
copolymer has an average molecular weight of 6500 Dalton
and that three molecules of cyclohexane are attributed to one
macrocycle, a density of 1.10 gcmÀ3 can be calculated for two
molecules present in the unit cell. The presence of cyclo-
hexane in the solid state structure is supported by the
observation that films of the block copolymer cast from
cyclohexane and stored for seven days at ambient conditions
contain between two and four molecules of cyclohexane per
coil ring coil block copolymer molecule, as determined by
proton NMR analysis. In addition, the single-crystal X-ray
analysis of several similar macrocycles show that the com-
pounds crystallize as solvates to fill the empty interior of the
[23]
contact withthe cyclohexane.
The observation that upon evaporation of the cyclohexane
the periodicity of the columnar stacking is lost further
supports the assumption that the included cyclohexane
molecules are located in the crystalline layers. Again, this is
closely analogous to the crystal structures of various macro-
cycles. Moreover, the fact that the superstructure is formed
only in the presence of an appropriate solvent indicates that it
plays a crucial role not only for the aggregation of these
materials and the transition from the solution to the solid state
but also for the stabilization of the rigid parts of the block
copolymer in the crystalline state.
rings.[7g 20]
,
In all electron diffraction patterns high intensity is observed
near reflections 3k1, 4k1, and 5k1 and the corresponding
≈
reflections withteh Miller index
h instead of h. This
observation suggests that the macrocycles form a herring-
bone-like packing in the crystalline layers of the material.
These crystalline layers are separated by amorphous layers
that contain the polystyrene substituents. The thickness of one
double layer consisting of one crystalline layer (rings) and one
amorphous layer (PS) is 72 ä. A model for the state of order
in the investigated samples is shown in Figure 8. It shows that
the coil ring coil block copolymer 1c in the solid state
Conclusion
We have shown that the coil ring coil block copolymer 1c
aggregates by slow solvent evaporation under equilibrium
conditions into a (solvated) material witha lamellar morphol-
ogy. The rigid cyclic domains
crystallize and are separated by
amorphous PS layers. Driving
forces are the microphase sep-
aration of the rigid and the coil
blocks and the solvophobic ag-
gregation of the macrocyclic
segments into crystalline do-
mains. This morphology is dif-
ferent from the aggregate struc-
ture in solution where individ-
ual stacks are covered by the PS
shell. These results show that a
Figure 8. Aggregation of supramolecular polymer brushes in the solid state into a lamellar superstructure.
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G. Lieser, S. Hˆger et al.
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*
Figure 9. a) In rod coil block copolymers the rod tilt increases the average separation between junctions (here ™ ∫) (adapted from ref. [21]). b) In 1c the
ring tilt increases the distance between junctions within a stack (c axis) but the distance between junctions of adjacent stacks (a axis) is reduced.
solution were added to 10 mL of a 0.1 molLÀ1 matrix solution, dissolved in
THF. In all cases 1,8,9-trihydroxyanthracene (Aldrich, Steinheim) was used
prediction of the solid state structure on the basis of the
solution structure and vice versa is not possible.
as matrix. A 1 mL portion of this mixture was applied to the multistage
Ongoing investigations on coil ring coil block copoly-
mers withdifferent numbers and kinds of coil segments will
show how these factors influence the superstructure of the
materials. Of special interest is the synthesis and investigation
of intraannular functionalized ring-coil block copolymers and
their aggregation to intraannular functionalized nanorods.
target and airdried.[24] Microanalysis was performed at the University of
Mainz. Melting points were measured with a Reichert hot stage apparatus
and are uncorrected.
Anionic polymerization: The anionic polymerizations were carried out in
cyclohexane under a nitrogen atmosphere in a glass ampoule. Cyclohexane
was purified by titration of diphenylethene using nBuLi until the color of
the solution turned red and was distilled under reduced pressure. Styrene
was purified by stirring withsolid fluorenyllithium (from fluorene and
nBuLi and removal of the solvent) for several minutes at room temperature
and distilled under reduced pressure. sec-Butyllithium (1.3m solution in
cyclohexane/hexane 92/2 v/v) and CO2 were used as received.
Experimental Section
General methods: Commercially available chemicals were used as
received. THF was distilled over potassium prior to use. Piperidine and
pyridine were distilled from CaH2 and stored under argon. Dichloro-
methane of quality ™water-free∫ was purchased and used as received.
4-(Dimethylamino)-pyridinium/p-toluenesulfonate (DMAP/p-TsOH) was
prepared by mixing equimolar amounts of the acid and the base in
dichloromethane and precipitation of the salt by the addition of diethyl
ether. After filtration and drying in vacuum the catalyst was used without
further purification. All other solvents (p.a. quality) and reagents were used
as received. Unless otherwise stated, acid, base, and salt solutions are
X-ray scattering: X-ray scattering was performed on a Philips PW 1820
X-ray diffractometer in reflection mode (CuKa, 1.541 ä). Samples were
prepared by drop casting a solution of 1c in cyclohexane on a glass slide and
slow evaporation of the solvent in the presence of additional cyclohexane
(in a slightly covered desiccator).
Electron diffraction: Electron diffraction was performed on a LEO912
transmission electron microscope operated at high voltage (120 kV). The
instrument was equipped withan integrated electron energyloss spectrom-
eter. The width of the energy window was set to dE ˆ 15 eV. The camera
lengthwas calibrated by using a TlCl powder sample. Once it was evident
that solvent was retained in the samples which could escape in the high
vacuum of the TEM, the samples were cast onto carbon-coated glass slides.
Sample preparation was performed as described above. The carbon films
with the sample were floated off the glass and transferred onto copper
specimen grids. They were inserted into the high vacuum of the electron
microscope in a GATAN cryo-transfer holder, Model626, at temperatures
below 08C. The electron microscopic investigation was then carried out at
temperatures below À508C.
1-tert-Butyl-3-[2-{4-(2-triethylsilylethynyl)phenyl}ethynyl]-5-(2-triisopro-
pylsilylethynyl)benzene (3): 4-Bromoiodobenzene (10.0 g, 35.3 mmol) and
triphenylposphine (0.38 g) were dissolved in piperidine (245 mL) under
argon. The solution was cooled to 08C and 2-triethylsilylacetylene (5.44 g,
38.7 mmol), [PdCl2(PPh3)2] (0.38 g) and CuI (0.19 g) were added. The
mixture was stirred overnight at room temperature. The solution was then
heated to 508C for 1 h and 1-ethynyl-3-(2-triisopropylsilylethynyl)-5-tert-
butylbenzene[11a] (14.13 g, 41.72 mmol) was added and the solution stirred
at this temperature for four days. After the mixture was cooled to room
temperature, diethyl ether and water were added, the organic phase was
1
aqueous. H NMR and 13C NMR spectra were recorded on a Bruker AC-
300 (300 MHz for proton, 75.48 MHz for carbon). Thin-layer chromatog-
raphy was performed on aluminum plates pre-coated with Merck 5735
silica gel 60 F254. Column chromatography was performed with Merck silica
gel 60 (230 400 mesh). Radial chromatography was performed with Merck
silica gel 60 PF254 containing CaSO4. The gel permeation chromatograms
were measured in THF (flow rate 1 mLminÀ1) at room temperature, using a
combination of three styragel columns (porosity 103, 105, and 106), an RI
detector and an UV detector operating at l ˆ 254 nm. The molecular
weight was obtained from polystyrene-calibrated SEC columns. The
matrix-assisted laser desorption ionization time-of-flight measurements
were carried out on a Bruker reflex spectrometer (Bruker, Bremen),
6
incorporating a 337 nm nitrogen laser witha 3 ns pulse duration (10
107 WcmÀ1, 100 mm spot diameter). The instrument was operated in a linear
mode withan accelerating potential of 33.65 kV. The mass scale was
calibrated withpolystyrene ( Mp ˆ 4700), using a number of resolved
oligomers. Samples were prepared by dissolving the macrocycle in THFat a
concentration of 10À4 molLÀ1. A 10 mL portion of this solution and 10 mL of
a 10À3 molLÀ1 silver trifluoroacetate (lithium trifluoroacetate, respectively)
3488
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
Chem. Eur. J. 2003, 9, 3481 3491

Coil Ring Coil Block Copolymers
3481 3491
separated, and washed with water, 10% acetic acid, 10% sodium
hydroxide, and saturated NaCl solution. After the solution was dried over
MgSO4 and the solvent was evaporated, the crude product was purified by
column chromatography using petroleum ether as eluent (Rf ˆ 0.38) to give
3 (17.5 g, 91%) as a white powder. 1H NMR (CDCl3): d ˆ 0.66 (q, J ˆ
7.99 Hz, 6H), 1.03 (t, J ˆ 7.62 Hz, 9H), 1.13 (s, 21H), 1.31 (s, 9H), 7.40
7.50 ppm (m, 7H); 13C NMR (CDCl3): d ˆ 4.43, 7.47, 11.36, 31.10, 34.68,
88.96, 90.64, 90.97, 93.87, 105.92, 106.72, 122.82, 123.11, 123.25, 123.54,
128.79, 129.04, 131.40, 131.98, 132.39, 151.53 ppm; MS(FD): m/z: 552.7
using petroleum ether/dichloromethane (2:1) as eluent (Rf ˆ 0.53). After
evaporation of the solvent and drying under vacuum, 6 was obtained as an
almost white powder (3.0 g, 78%). M.p.: 728C; 1H NMR (CDCl3): d ˆ 1.12
(s, 42H), 1.32 (s, 18H), 1.50 1.60 (m, 4H), 1.75 1.90 (m, 4H), 3.99 (t, J ˆ
6.32 Hz, 2H), 4.34 (t, J ˆ 6.62 Hz, 2H), 7.02 (d, J ˆ 1.27 Hz, 2H), 7.29 (t, J ˆ
1.25 Hz, 1H), 7.38 7.55 (m, 17H), 8.03 ppm (m, 2H); 13C NMR (CDCl3):
d ˆ 11.32, 18.67, 25.75, 25.84, 28.68, 29.04, 31.08, 34.67, 64.90, 68.09, 88.91,
89.42, 90.42, 90.65, 91.10, 106.65, 117.90, 122.74, 122.82, 123.18, 123.50,
124.29, 128.33, 128.79, 129.08, 129.52, 129.98, 131.59, 132.38, 132.83, 151.52,
‡
‡
‡
[M ], 1105.1 [2M ]; elemental analysis calcd (%) for C37H52Si2 (552.98): C
152.29 ppm; MS (FD): m/z: 1169.8 [M ]; elemental analysis calcd (%) for
80.36, H 9.48; found: C 80.31, H 9.59.
C81H94O3Si2 (1171.78): C 83.02, H 8.09; found: C 82.81, H 8.13.
1-tert-Butyl-3-[2-(4-ethynylphenyl)ethynyl]-5-(2-triisopropylsilylethynyl)-
benzene (4): K2CO3 (18.6 g, 134 mmol) was added to a solution of 3
(17.55 g, 32 mmol) in THF/methanol (2:1) (250 mL) and stirred for four
days at room temperature. Diethyl ether and water were added, the organic
phase was separated and washed with water and saturated NaCl solution.
After the solution was dried over MgSO4 and the solvent was evaporated,
the crude product was purified by recrystallization from a mixture of
methanol/ethanol (3:1) to give 4 as a white powder (11.8 g, 83%). M.p.:
758C; 1H NMR (CDCl3): d ˆ 1.13 (s, 21H), 1.31 (s, 9H), 3.16 (s, 1H), 7.40
7.50 ppm (m, 7H); 13C NMR (CDCl3): d ˆ 11.36, 18.69, 31.10, 34.69, 78.92,
88.71, 90.70, 91.12, 106.69, 121.99, 122.74, 123.56, 128.79, 129.12, 131.50,
6-[3,5-Bis(2-{4-[2-(3-tert-butyl-5-ethynyl)phenylethynyl]phenylethynyl})-
phenoxy]hexyl benzoate (7): A solution of Bu4NF in THF (1m, 5.5 mL,
5.5 mmol) was added to a solution of 6 (3.0 g, 2.57 mmol) in THF (10 mL).
After the mixture was stirred overnight at room temperature, diethyl ether
and water were added. The organic phase was separated and washed with
water and saturated NaCl solution, and then dried over MgSO4. After
evaporation of the solvent, the crude product was purified by column
chromatography using petroleum ether/dichloromethane (1:1) as eluent
(Rf ˆ 0.55). After evaporation of the solvent and drying under vacuum, 7
was obtained as a white powder (2.03 g, 93%). M.p.: 528C; 1H NMR
(CDCl3): d ˆ 1.31 (s, 18H), 1.50 1.60 (m, 4H), 1.75 1.90 (m, 4H), 3.06
(s.2H), 3.99 (t, J ˆ 6.15 Hz, 2H), 4.33 (t, J ˆ 6.47 Hz, 2H), 7.02 (d, J ˆ
1.42 Hz, 2H), 7.29 (t, J ˆ 1.42 Hz, 1H), 7.35 7.55 (m, 17H), 8.00
8.05 ppm (m, 2H); 13C NMR (CDCl3): d ˆ 25.76, 25.84, 28.68, 29.04,
31.05, 34.69, 64.90, 68.09, 77.18, 89.07, 89.41, 90.47, 90.89, 117.92, 122.09,
122.91, 123.10, 124.29, 128.33, 129.26, 129.45, 131.60, 132.25, 132.83, 151.52,
‡
‡
132.08, 132.39, 151.56 ppm; MS (FD): m/z: 438.2 [M ], 879.3 [2M ], 1318.3
‡
[3M ]; elemental analysis calcd (%) for C31H38Si (438.72): C 84.87, H 8.73;
found: C 84.88, H 8.69.
6-(3,5-Diiodophenoxy)hexyl benzoate (5): 3,5-Diiodophenol (5.28 g,
15.0 mmol), 6-bromo-1-hexanol (2.78 g, 15.0 mmol), and K2CO3 (4.26 g,
30.0 mmol) were stirred in DMF (30 mL) at 608C overnight under argon.
After the mixture was cooled to room temperature, diethyl ether and water
were added to the brown suspension and the organic phase was separated
and washed four times with water, and then saturated NaCl solution and
dried over MgSO4. After filtration of the solution and evaporation of the
solvent, the crude product was purified by column chromatography using
diethyl ether/petroleum ether (3:1) as eluent (Rf ˆ 0.48). After evaporation
of the solvent and drying under vacuum, 6-(3,5-diiodophenoxy)-hexan-1-ol
was obtained as a white powder (6.5 g, 79%). M.p.: 468C; 1H NMR
(CDCl3): d ˆ 1.34 1.47 (m, 4H), 1.57 (m, 2H), 1.74 (m, 2H), 3.63 (t, J ˆ
6.65 Hz, 2H), 3.86 (t, J ˆ 6.65 Hz, 2H), 7.17 (d, J ˆ 1.27 Hz, 2H), 7.58 ppm
(t, J ˆ 1.27 Hz, 1H); 13C NMR (CDCl3): d ˆ 25.42, 25.72, 28.95, 32.57, 62.79,
‡
158.79 ppm; MS (FD): m/z: 858.0 [M ]; elemental analysis calcd (%) for
C63H54O3 (859.10): C 88.08, H 6.34; found: C 88.06, H 6.28.
Macrocycle 8: A solution of 7 (0.60 g, 0.64 mmol) in pyridine (15 mL) was
added to a suspension of CuCl (3.82 g) and CuCl2 (0.75 g) in pyridine
(120 mL) over 96 hat 55 8C. After completion of the addition, CH2Cl2 and
water were added and the organic phase was separated and washed with
water, 25% aqueous NH3 solution (until the aqueous phase remained
nearly colorless), 10% acetic acid, 10% sodium hydroxide, and saturated
NaCl solution, and dried over MgSO4. After evaporation of the solvent to
about 20 mL, the coupling products were precipitated by the addition of
methanol (100 mL) and collected by filtration. The crude product was
purified by double column chromatography. The first used a mixture of
petroleum ether/dichloromethane (1:3) as eluent (Rf ˆ 0.83), the second
used a mixture of petroleum ether/dichloromethane (1:2) as eluent (Rf ˆ
0.69). After evaporation of the solvent and drying under vacuum, pure 8
was obtained as a white powder (0.30 g, 50%). M.p.: >2508C (decomp);
1H NMR (CDCl3): d ˆ 1.32 (s, 36H), 1.50 1.60 (m, 8H), 1.75 1.90 (m,
8H), 3.99 (t, J ˆ 6.15 Hz, 4H), 4.33 (t, J ˆ 6.47 Hz, 4H), 7.01 (d, J ˆ 1.40 Hz,
4H), 7.33 (t, J ˆ 1.25 Hz, 2H), 7.33 7.58 (m, 34H), 8.00 8.08 ppm (m, 4H);
13C NMR (CDCl3): d ˆ 25.78, 25.86, 28.71, 29.07, 31.07, 34.80, 64.92, 68.09,
73.93, 81.32, 89.39, 89.46, 90.53, 90.75, 117.71, 121.84, 123.07, 123.25, 124.34,
128.35, 129.55, 131.65, 132.83, 133.13, 151.92, 158.89 ppm; GPC: single peak
‡
68.29, 94.54, 123.40, 137.30, 159.84 ppm; MS (FD): m/z: 445.6 [M ];
elemental analysis calcd (%) for C12H16I2O2 (446.06): C 32.31, H 3.62;
found: C 33.11, H 3.73.
6-(3,5-Diiodophenoxy)hexan-1-ol (6.49 g, 14.5 mmol) and benzoyl chloride
(2.1 g, 14.9 mmol) were dissolved in THF (20 mL) under argon. The
mixture was cooled to 08C and pyridine (1.5 g, 18.9 mmol) was slowly
added (accompanied with the formation of a white precipitate). After the
mixture was stirred overnight at room temperature, diethyl ether and water
were added and the organic phase was separated and washed with water,
10% acetic acid, 10% sodium hydroxide, and saturated NaCl solution. The
organic phase was dried over MgSO4 and after filtration and evaporation of
the solvent, the crude product was purified by column chromatography
using a mixture of dichloromethane/petroleum ether (1:1) as eluent (Rf ˆ
0.36). After evaporation of the solvent and drying under vacuum, 5 was
‡
at Mw ˆ 2700; MS (FD): m/z: 1713.9 [M ]; elemental analysis calcd (%) for
C126H104O6 (1714.17): C 88.28, H 6.12; found: C 88.29, H 6.19.
Macrocycle 9: 10% potassium hydroxide (3 mL) was added to a solution of
8 (0.4 g, 0.23 mmol) in THF (20 mL). The mixture was refluxed at 668C
overnight. The solvent volume was reduced to about 5 mL and the
macrocycle was precipitated by the addition of methanol. After filtration
and drying under vacuum, 9 was obtained as a white powder (0.3 g, 87%).
1
obtained as a white powder (7.0 g, 88%). M.p.: 568C; H NMR (CDCl3):
d ˆ 1.45 1.55 (m, 4H), 1.70 1.85 (m, 4H), 3.87 (t, J ˆ 6.32 Hz, 2H), 4.32 (t,
J ˆ 6.32 Hz, 2H), 7.16 (d, J ˆ 1.25 Hz, 2H), 7.35 7.45 (m, 2H), 7.50 7.60
(m, 2H), 7.95 8.05 ppm (m, 2H); 13C NMR (CDCl3): d ˆ 25.63, 25.75,
28.60, 28.88, 64.82, 68.20, 94.56, 123.35, 128.31, 129.48, 130.38, 132.81,
1
M.p.: >2508C (decomp); H NMR (CDCl3): d ˆ 1.32 (s, 36H), 1.35 1.68
(m, 12H), 1.75 1.88 (m, 4H), 3.66 (t, J ˆ 6.3 Hz, 4H), 3.98 (t, J ˆ 6.57 Hz,
4H), 7.01 (d, J ˆ 1.35 Hz, 4H), 7.33 (t, J ˆ 1.25 Hz, 2H), 7.51 (s, 20H), 7.52
7.55 ppm (m, 8H); 13C NMR (CDCl3): d ˆ 25.57, 25.90, 29.20, 31.10, 32.76,
34.82, 62.92, 68.37, 74.03, 81.40, 89.46, 89.51, 90.59, 90.81, 117.85, 121.97,
123.14, 123.39, 124.45, 127.97, 129.45, 131.68, 133.19, 152.01, 159.03 ppm;
‡
137.29, 159.79, 166.59 ppm; MS (FD): m/z: 549.6 [M ]; elemental analysis
calcd (%) for C19H20I2O3 (549.8): C 41.48, H 3.66; found: C 41.32, H 3.83.
6-[3,5-Bis{2-(4-{2-[3-tert-butyl-5-(2-triisopropylsilylethynyl)]phenylethy-
nyl}phenylethynyl)}phenoxy]hexyl benzoate (6): [Pd2(dba)3] (85 mg;
dba ˆ dibenzylideneacetone) and CuI (43 mg) were added to a solution
of 4 (2.9 g, 6.6 mmol), 5 (1.82 g, 3.3 mmol), and triphenylphosphine (85 mg)
in triethylamine (20 mL) and the mixture was stirred at room temperature
under argon for three days. Then, the solution was heated for an additional
hour to 508C. After the mixture was cooled to room temperature, diethyl
ether and water were added, and the organic phase was separated and
washed with water, 10% acetic acid, 10% sodium hydroxide, and saturated
NaCl solution. After the solution was dried over MgSO4 and the solvent
was evaporated, the crude product was purified by column chromatography
‡
GPC: single peak at Mw ˆ 2200; MS (FD): m/z: 1504.4 [M ]; elemental
analysis calcd (%) for C112H96O4 (1506.08): C 89.33, H 6.43; found: C 88.78;
H 6.37.
PS-COOH (10): Cyclohexane (100 mL) and styrene (10 mL) were placed
in an ampoule and the appropriate amount of sec-butyllithium was added
through a syringe. After 3 h at room temperature, a small amount (ꢀ1 mL)
of the solution was quenched with methanol (10 mL) and the molecular
weight (peak molecular weight Mp is given here) and the polydispersity D
of the polystyrene was determined by GPC analysis. The rest of the solution
Chem. Eur. J. 2003, 9, 3481 3491
www.chemeurj.org
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3489

G. Lieser, S. Hˆger et al.
FULL PAPER
was transferred into THF (500 mL) saturated withCO and the resulting
[2] Reviews about rod coil block copolymers: a) M. Lee, B.-K. Cho, W.-
C. Zin, Chem. Rev. 2001, 101, 3869 3892; b) H.-A. Klok, S.
Lecommandoux, Adv. Mater. 2001, 13, 1217 1229; c) G. Mao, C. K.
Ober, Acta Polymer. 1997, 48, 405 422.
[3] a) S. Rosselli, A.-D. Ramminger, T. Wagner, B. Silier, S. Wiegand, W.
H‰u˚ler, G. Lieser, V. Scheumann, S. Hˆger, Angew. Chem. 2001, 113,
3234 3237; Angew. Chem. Int. Ed. 2001, 40, 3138 3141; b) S. Hˆger,
K. Bonrad, S. Rosselli, A.-D. Ramminger, T. Wagner, B. Silier, S.
Wiegand, W. H‰u˚ler, G. Lieser, V. Scheumann, Macromol. Symp.
2002, 177, 185 191.
[4] Reviews about shape-persistent macrocycles: a) J. S. Moore, Acc.
Chem. Res. 1997, 30, 402 413; b) S. Hˆger, J. Polym. Sci, PartA 1999,
37, 2685 2698; c) M. M. Haley, J. J. Pak, S. C. Brand, Topic Curr.
Chem. 1999, 201, 81 130; d) C. Grave, A. D. Schl¸ter, Eur. J. Org.
Chem. 2002, 3075 3098.
[5] For the concept of intraannular functional groups, see, for example:
a) F. Vˆgtle, P. Neumann, Tetrahedron 1970, 26, 5299 5318; b) E.
Weber, F. Vˆgtle, Chem. Ber. 1976, 109, 1803 1831.
[6] For shape-persistent macrocycles containing intraannular functional
groups, see, for example: a) H. L. Anderson, J. K. M. Sanders, J.
Chem. Soc. Chem. Commun. 1992, 946 947; b) S. Anderson, U.
Neidlein, V. Gramlich, F. Diederich, Angew. Chem. 1995, 107, 1722
1726; Angew. Chem. Int. Ed. Engl. 1995, 34, 1596 1600; c) D. L.
Morrison, S. Hˆger, J. Chem. Soc. Chem. Commun. 1996, 2313 2314;
d) Y. Tobe, N. Utsumi, K. Kawabata, A. Nagano, K. Naemura, Angew.
Chem. 1998, 110, 1347 1349; Angew. Chem. Int. Ed. Engl. 1998, 37,
1285 1287; e) S. Hˆger, A.-D. Meckenstock, Chem. Eur. J. 1999, 5,
1686 1691; f) U. Lehman, A. D. Schl¸ter, Eur. J. Org. Chem. 2000,
3483 3487; g) Y. Hosokawa, T. Kawase, M. Oda, J. Chem. Soc. Chem.
Commun. 2001, 1948 1949; h) M. Fischer, S. Hˆger, Eur. J. Org.
Chem. 2003, 441 446.
2
solution was acidified with methanolic HCl. After evaporation of the
solvent the PS-carboxylic acid was purified by column chromatography
using toluene as eluent to remove all impurities (Rf ꢀ 0.9). The free acid
was obtained by elution withTHF and evaporation of the solvent (isolated
yields:
60 80%).
1H
NMR
(CDCl3):
d ˆ 0.6 0.8
(br,
CH3CH2CH(PS)CH3, 6H), 0.8 2.6 (br), 3.3 3.5 (br, (PS)PhCH-COOH,
1H), 6.3 7.5 ppm (br). From the MALDI-TOF data of the acid the degree
of polymerization (n) for the most intensive peak can be calculated.
10a: GPC (methanol-quenched anion): Mw ˆ 1030 gmolÀ1
;
D ˆ 1.19;
MS(MALDI-TOF) (PS-COOH, most intensive peak): m/z: 1145.2
‡
[M‡Ag ] (n ˆ 9); elemental analysis calcd (%) for C77H82O2 (1039.59): C
88.96, H 7.97; found: C 88.05, H 8.14.
10b: GPC (methanol-quenched anion): Mw ˆ 1580 gmolÀ1
;
D ˆ 1.16;
MS(MALDI-TOF) (PS-COOH, most intensive peak): m/z: 1665.4
‡
[M‡Ag ] (n ˆ 14); elemental analysis calcd (%) for C117H122O2 (1560.39):
C 90.05, H 7.90; found: C 88.89, H, 8.22.
10c: GPC (methanol-quenched anion): Mw ˆ 2430 gmolÀ1
;
D ˆ 1.06;
MS(MALDI-TOF) (PS-COOH, most intensive peak): m/z: 2607.5
‡
[M‡Ag ] (n ˆ 23); elemental analysis calcd (%) for C189H194O2 (2497.83):
C 90.88, H 7.84, found: C 90.34, H 7.72.
10d: GPC (methanol-quenched anion): Mw ˆ 3650 gmolÀ1
;
D ˆ 1.10;
MS(MALDI-TOF) (PS-COOH, most intensive peak): m/z ˆ 3543.6
‡
[M‡Ag ] (n ˆ 32); elemental analysis calcd (%) for C261H266O2 (3435.27):
C 91.25, H 7.82; found: C 91.30, H 7.45.
10e: GPC (methanol-quenched anion): Mw ˆ 5600 gmolÀ1
;
D ˆ 1.03;
MS(MALDI-TOF) (PS-COOH, most intensive peak): m/z: 5319.5
‡
[M‡Li ] (n ˆ 50); elemental analysis calcd (%) for C405H410O2 (5310.15):
C 91.60, H 7.80, found: C 91.24, H 7.94.
Block copolymers 1: Compounds
9
(50 mg, 0.0332 mmol), 10
[7] For channel structures based on shape-persistent macrocycles see for
example: a) D. Venkataraman, S. Lee, J. Zhang, J. S. Moore, Nature
1994, 371, 591 593; b) D. T. Bong, T. D. Clark, J. R. Granja, M. R.
Ghadiri, Angew. Chem. 2001, 113, 1016 1041; Angew. Chem. Int. Ed.
Engl. 2001, 40, 988 1011; c) G. Gattuso, S. Menzer, S. A. Nepogodiev,
J. F. Stoddart, D. J. Wiliams, Angew. Chem. 1997, 107, 1615 1617;
Angew. Chem. Int. Ed. Engl. 1997, 36, 1451 1454; d) O. Henze, D.
Lentz, A. D. Schl¸ter, Chem. Eur. J. 2000, 6, 2362 2367; e) P. M¸ller,
(0.0731 mmol), and DMAP/p-TsOH (43 mg, 0.15 mmol) were dissolved
in dry CH2Cl2 (15 mL) by gentle warming. After the mixture was cooled to
room temperature, diisopropyl carbodiimide (18 mg, 0.15 mmol) was
added and the mixture stirred for three days. The solvent was evaporated
and the crude product was purified by column chromatography using
dichloromethane as eluent (Rf ˆ 0.93). After evaporation of the solvent and
drying under vacuum, 1 was obtained as a white powder. 1H NMR (CDCl3):
d ˆ 0.6 0.8 (br, CH3CH2CH(PS)CH3, 6H), 0.8 2.6 (br), 1.32 (s, 36H)
3.0 3.2 (br, (PS)PhCH-COOH, 1H), 3.7 4.0 (br, Ar-O-CH2-; CH2-
OCO(PS)) 6.3 7.4 (br), 7.33 (m, 2H), 7.51 (s, 20H), 7.54 ppm (m, 8H).
From the MALDI-TOF data the degree of polymerization (n‡n) of th e
styrene for the most intensive peak can be calculated.
¬
I. Uson, V. Hensel, A. D. Schl¸ter, G. M. Sheldrick, Helv. Chim. Acta
2001, 84, 778 785; f) R. A. Pascal, Jr., L. Barnett, X. Qiao, D. M. Ho,
J. Org. Chem. 2000, 65, 7711 7717; g) S. Hˆger, D. L. Morrison, V.
Enkelmann, J. Am. Chem. Soc. 2002, 124, 6734 6736.
[8] This is remarkable in the context that shape-persistent macrocycles of
similar structure witholigo-alkyl side chains of defined lengthdo not
dissolve in this solvent. This shows the superior solubilizing properties
of PS oligomers over oligo-alkyl substituents.
[9] The investigation of the exact nature of the driving force for the
aggregation of the ring-coil block copolymers is currently under way.
[10] U. Lauter, W. H. Meyer, G. Wegner, Maromolecules 1997, 30, 2092
2102.
[11] For a template-directed approachtowards these structures, see also:
a) S. Hˆger, A.-D. Meckenstock, H. Pellen, J. Org. Chem. 1997, 62,
4556 4567; b) S. Hˆger, A.-D. Meckenstock, Tetrahedron Lett. 1998,
39, 1735 1736; c) S. Hˆger, Macromol. Symp. 1999, 142, 185 191.
[12] P. Siemsen, R. C. Livingston, F. Diederich, Angew. Chem. 2000, 112,
2740 2767; Angew. Chem. Int. Ed. 2000, 39, 2632 2657.
[13] P. Fitton, A. E. Rick, J. Organomet. Chem. 1971, 28, 287 291.
[14] a) C. Eaborn, D. R. M. Walton, J. Organomet. Chem. 1965, 4, 217
228; b) C. R¸cker, Chem. Rev. 1995, 95, 1009 1064.
1a: (32% yield) GPC: Mw ˆ 4710 gmolÀ1; D ˆ 1.05; MS(MALDI-TOF)
‡
(most intensive peak): m/z: 3464 [M‡Na ] (n‡n ˆ 17); elemental analysis
calcd (%) for C258H248O6 (3445.07): C 90.00, H 7.27; found: C 88.05, H 7.98.
1b: (86% yield) GPC: Mw ˆ 5460 gmolÀ1; D ˆ 1.09; MS(MALDI-TOF)
‡
(most intensive peak): m/z: 4194 [M‡Na ] (n‡n ˆ 27); elemental analysis
calcd (%) for C322H312O6 (4278.34): C 90.43, H 7.37; found: C 87.69, H 8.01.
1c: (84% yield) GPC: Mw ˆ 8320 gmolÀ1; D ˆ 1.05; MS(MALDI-TOF)
‡
(most intensive peak): m/z: 6587 [M‡Na ] (n‡n ˆ 47); elemental analysis
calcd (%) for C498H488O6 (6569.86): C 91.04, H 7.50; found: C 90.74, H 7.72.
1d: (64% yield) GPC: Mw ˆ 10100 gmolÀ1; D ˆ 1.04; MS(MALDI-TOF)
‡
(most intensive peak): m/z: 8360 [M‡Na ] (n‡n ˆ 64); elemental analysis
calcd (%) for C634H624O6 (8340,58): C 91.29, H 7.56; found: C 90.59, H 7.99.
1e: (39% yield) GPC: Mw ˆ 13470 gmolÀ1; D ˆ 1.06; MS(MALDI-TOF)
‡
(most intensive peak): m/z: 11880 [M‡Ag ] (n‡n ˆ 97); elemental analysis
calcd (%) for C898H888O6 (11777.86): C 91.57 H 7.62; found: C 91.32, H 7.88.
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¬
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[18] Occasionally the layer lines show continuous intensity with some
sampling. We cannot exclude the fact that this feature is an indication
of partially evaporated solvent.
[19] As mentioned before, the reflections on the equator are smeared out
due to the overlap of reflection spikes owing to the necessarily small
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www.chemeurj.org
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Coil Ring Coil Block Copolymers
3481 3491
sample thickness and the small distance between adjacent planes in b*
direction (i.e. the superposition of h10 and h20 with h00 reflections).
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[23] It can be assumed that the pore size of the columns decreases with
increasing tilt angle of the macrocycles reducing the amount of
cyclohexane occupying the empty space.
[24] S. Hˆger, J. Spickermann, D. L Morrison, P. Dziezok, H. J. R‰der,
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Received: January 31, 2003 [F4796]
Chem. Eur. J. 2003, 9, 3481 3491
www.chemeurj.org
¹ 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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