Macrocyclic effects in the mesomorphic properties of liquid-crystalline pillar[5]- and pillar[6]arenes

Article abstract of DOI:10.1002/ejoc.201300356

Whereas the reaction of 1,4-bis(2-bromoethyloxy)benzene (4) with paraformaldehyde in the presence of BF₃·Et₂O afforded exclusively the cyclopentameric pillar[5]arene derivative (5), both cyclopenta- and cyclohexameric macrocycles 5 and 6 were obtained when the reaction of 4 with paraformaldehyde was performed at 45 °C in CHCl ₃ with FeCl₃ as the catalyst. Treatment of compounds 4-6 with sodium azide provided the corresponding polyazides, to which a cyanobiphenyl building block was subsequently grafted to generate model compound 1, pillar[5]arene 2, and pillar[6]arene 3, bearing two, ten and twelve mesomorphic subunits, respectively. The liquid-crystalline and thermal properties of the compounds were investigated by polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). Comparison of the liquid-crystalline properties of macrocycles 2 and 3 with those of 1 revealed the strong influence of the macrocyclic pillar[n]arene core on the mesomorphic properties. Whereas only a monotropic mesophase was observed for 1, a broad enantiotropic mesophase was evidenced for both pillar[n]arene derivatives. Pillar[n]arene (n = 5 or 6) derivatives substituted with peripheral mesogenic moieties gave rise to an enantiotropic smectic A phase over a very broad temperature range, whereas only a monotropic mesophase was observed for the corresponding constitutive acyclic monomeric subunit. Copyright

Full text of DOI:10.1002/ejoc.201300356

Job/Unit: O30356
/KAP1
Date: 29-04-13 10:47:17
Pages: 11
FULL PAPER
Liquid Crystals
Pillar[n]arene (n = 5 or 6) derivatives sub-
stituted with peripheral mesogenic moieties
gave rise to an enantiotropic smectic A
phase over a very broad temperature range,
whereas only a monotropic mesophase was
observed for the corresponding constitutive
acyclic monomeric subunit.
I. Nierengarten, S. Guerra, M. Holler,
L. Karmazin-Brelot, J. Barberá,*
R. Deschenaux,* J.-
F. Nierengarten* ............................. 1–11
Macrocyclic Effects in the Mesomorphic
Properties of Liquid-Crystalline Pillar[5]-
and Pillar[6]arenes
Keywords: Nanostructures / Macrocycles /
Liquid crystals / Structure elucidation /
Click chemistry
0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1

Job/Unit: O30356
/KAP1
Date: 29-04-13 10:47:17
Pages: 11
J. Barberá, R. Deschenaux, J.-F. Nierengarten et al.
FULL PAPER
DOI: 10.1002/ejoc.201300356
Macrocyclic Effects in the Mesomorphic Properties of Liquid-Crystalline
Pillar[5]- and Pillar[6]arenes
Iwona Nierengarten,[a] Sebastiano Guerra,[a,b] Michel Holler,[a] Lydia Karmazin-Brelot,[c]
Joaquín Barberá,*[d] Robert Deschenaux,*[b] and Jean-François Nierengarten*[a]
Dedicated to Dr. Raymond Ziessel on the occasion of his 60th birthday
Keywords: Nanostructures / Macrocycles / Liquid crystals / Structure elucidation / Click chemistry
Whereas the reaction of 1,4-bis(2-bromoethyloxy)benzene (4)
with paraformaldehyde in the presence of BF3·Et2O afforded
exclusively the cyclopentameric pillar[5]arene derivative (5),
both cyclopenta- and cyclohexameric macrocycles 5 and 6
were obtained when the reaction of 4 with paraformaldehyde
was performed at 45 °C in CHCl3 with FeCl3 as the catalyst.
Treatment of compounds 4–6 with sodium azide provided the
corresponding polyazides, to which a cyanobiphenyl build-
ten and twelve mesomorphic subunits, respectively. The li-
quid-crystalline and thermal properties of the compounds
were investigated by polarized optical microscopy (POM),
differential scanning calorimetry (DSC), and X-ray diffrac-
tion (XRD). Comparison of the liquid-crystalline properties of
macrocycles 2 and 3 with those of 1 revealed the strong influ-
ence of the macrocyclic pillar[n]arene core on the mesomor-
phic properties. Whereas only a monotropic mesophase was
ing block was subsequently grafted to generate model com- observed for 1, a broad enantiotropic mesophase was evi-
pound 1, pillar[5]arene 2, and pillar[6]arene 3, bearing two,
denced for both pillar[n]arene derivatives.
of one or more molecular entities to easily generate sophis-
ticated nanomolecules has attracted enormous interest.[2–5]
The recent development of efficient synthetic tools, namely
the so-called ‘click’ reactions,[6] greatly facilitated the emer-
gence of this field. As part of this research, we recently be-
came interested in the use of a pillar[5]arene core as a nano-
scaffold for the preparation of nanomaterials with a con-
trolled distribution of functional groups on the macrocyclic
framework.[7] Pillar[5]arenes are unique tubular-shaped
compounds composed of 1,4-disubstituted hydroquinone
subunits linked by methylene bridges in their 2,5-posi-
tions.[8–9] They are conveniently prepared from 1,4-dialk-
oxybenzene derivatives and paraformaldehyde in the pres-
ence of a Lewis acid catalyst.[10] Owing to the reversibility
of the Friedel–Crafts reaction, the cyclooligomerization is
thermodynamically driven, thus allowing pillar[5]arenes to
be obtained in high yields.[11] The reaction conditions are,
however, not compatible with a large variety of functional
groups and the direct synthesis of pillar[5]arenes bearing
sophisticated substituents is often not possible. The cycliza-
tion reaction is also sensitive to steric effects, and the pres-
ence of large substituents on the starting 1,4-dialkoxybenz-
ene considerably lowers the yields.[10] This major problem
was addressed by producing readily accessible pillar[5]arene
derivatives bearing ten terminal groups, allowing their fur-
ther functionalization to generate structurally more com-
plex systems.[7,12] For example, we have developed a pillar-
[5]arene building block bearing ten peripheral azide func-
Introduction
One important aspect of modern chemistry is the synthe-
sis of complex nanomolecules that exhibit specific proper-
ties for applications in materials science and biology.[1] It is
clear that synthetic chemistry has played a major role in
the recent advances of nanosciences and nanomedicine.[1]
However, the preparation of complex nanostructures com-
bining the required functional groups often remains diffi-
cult and requires a large number of synthetic steps, limiting
both their accessibility and applicability. In this light, the
design of versatile nanoscaffolds allowing for the grafting
[a] Laboratoire de Chimie des Matériaux Moléculaires, Université
de Strasbourg et CNRS (UMR 7509), Ecole Européenne de
Chimie, Polymères et Matériaux,
25 rue Becquerel, 67087 Strasbourg Cedex 2, France
E-mail: nierengarten@unistra.fr
Homepage: http://www-ecpm.u-strasbg.fr/umr7509/
WebLaboNierengarten.htm
[b] Institut de Chimie, Université de Neuchâtel,
Av. de Bellevaux 51, 2000 Neuchâtel, Switzerland
E-mail: robert.deschenaux@unine.ch
Homepage: http://www2.unine.ch/macrochem/page-6502.html
[c] Service de Radiocristallographie, Institut de Chimie, Université
de Strasbourg,
1 rue Blaise Pascal, B.P. 296/R8, 67008 Strasbourg Cedex,
France
[d] Departamento de Química Orgánica, Instituto de Ciencia de
Materiales de Arágon, Universidad de Zaragoza – CSIC,
50009 Zaragoza, Spain
E-mail: jbarbera@unizar.es
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201300356.
2
www.eurjoc.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O30356
/KAP1
Date: 29-04-13 10:47:17
Pages: 11
Macrocyclic Effects in Pillar[5]- and Pillar[6]arenes
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3

Job/Unit: O30356
/KAP1
Date: 29-04-13 10:47:17
Pages: 11
J. Barberá, R. Deschenaux, J.-F. Nierengarten et al.
FULL PAPER
Scheme 1. Preparation of the azide building blocks. Reagents and conditions: (i) (CH2O)n, BF3·Et2O, CH2ClCH2Cl, room temp. (5: 40%);
(ii) (CH2O)n, FeCl3, CHCl3, 45 °C (5: 15%; 6: 30%); (iii) NaN3, DMF, room temp. (7: 97%; 8: 98%; 9: 92%).
tions and shown that the copper-mediated Huisgen 1,3-di- thus systematically investigated in the particular case of
polar cycloaddition of azides and alkynes resulting in 1,2,3- starting material 4. FeCl3 and CHCl3 appeared to be suit-
triazoles is an ideal tool with which to efficiently produce able, but both the temperature and the reaction time played
functionalized pillar[5]arenes.[7] This building block was an important role in the outcome of the reaction. The high-
decorated with cyanobiphenyl moieties, thus providing the est yields in pillar[6]arene were obtained when the reaction
first example of a liquid-crystalline pillar[5]arene (com- mixture was stirred for more than 3 d at temperatures
pound 2).[7] Importantly, comparison of its mesomorphic higher than 45 °C. Furthermore, it was also noticed that the
properties with those of model compound 1 revealed a dra- use of an excess of paraformaldehyde favored the formation
matic influence of the pillar[5]arene core. Indeed, whereas of the cyclohexamer. Under optimized conditions, the reac-
only a monotropic mesophase was observed for 1, a broad tion of 4 (1 equiv.) with a large excess of paraformaldehyde
enantiotropic mesophase was evidenced by linking together (5 equiv.) in the presence of FeCl3 (0.2 equiv.) in CHCl3 at
five linear subunits through the central macrocyclic pillar- 45 °C for 3 d gave both 5 and 6. After work-up, compounds
[5]arene core in 2. Clearly, the macrocyclic core unit is cap- 5 and 6 were conveniently separated by column chromatog-
able of providing orientational and/or positional disorder raphy on SiO2 and were isolated in 15 and 30% yield,
1
within the smectic layers to prevent crystallization but also respectively. The H and 13C NMR spectra of 5 and 6 are
intermolecular π–π interactions between neighboring cores similar, but mass spectrometry provided definitive struc-
to stabilize the lamellar phase. An important question re- tural assignments.
mains open however: Is this a general macrocyclic effect or
For compound 6, crystals suitable for X-ray crystal struc-
does it result from the peculiar fivefold symmetry[13] of the ture analysis were obtained by slow diffusion of hexane into
pillar[5]arene core? To answer to this question, we now re- a CHCl3/PhCN (2:1) solution of 6. As shown in Figure 1,
port a full account on this work, including the preparation 6 has a hexagon-like cyclic structure with two benzonitrile
of the corresponding sixfold symmetrical pillar[6]arene de- molecules included in its cavity. Interestingly, the relative
rivative 3.
orientation of the two PhCN molecules located in the same
macrocycle is not antiparallel. The dipole moment thus
generated may play an important role in the supramolecular
organization within the crystal lattice (see above). The
average bond angle for the methylene bridge in 6 is 114.2°,
and differs significantly from both the ideal 109.5° angle for
sp3 hybridized carbons and the theoretical 120° internal an-
gle for an unstrained hexagon. As a result, all the six aro-
matic subunits of 6 are slightly bent by about 1.6 to 4.2°.
To further accommodate the strain across the methylene
bridges, the six CH2 moieties are not located in the same
plane. Indeed, a deviation of 0.395 and 0.513 Å is observed
for two methylene centers from the plane encompassing the
four other centers. With its D6-symmetrical structure, com-
pound 6 is chiral and crystallizes as a racemate. Close in-
spection of the packing down the crystallographic a axis
reveals alternating layers of both enantiomers (Figure 1, b).
Layers a–b are related to the aЈ–bЈ layers by a crystallo-
Results and Discussion
Synthesis
As shown in Scheme 1, pillar[5]arene derivative 5 was ob-
tained from compound 4. Treatment of 4 and paraform-
aldehyde with BF3·Et2O in 1,2-dichloroethane gave pillar-
[5]arene 5 in 40% yield.[14] Under these conditions, no trace
of the corresponding pillar[6]arene derivative 6 could be de-
tected.
Our initial attempts to prepare compound 6 from 4 un-
der the conditions recently reported for the preferential
preparation of pillar[6]arenes[15] (FeCl3/CHCl3) gave, at
best, pillar[5]arene 5, but no trace of the corresponding pil-
lar[6]arene derivative 6. The reaction conditions (solvent,
catalyst, stoichiometry, temperature, reaction time) were
4
www.eurjoc.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O30356
/KAP1
Date: 29-04-13 10:47:17
Pages: 11
Macrocyclic Effects in Pillar[5]- and Pillar[6]arenes
graphic glide plane. The macrocycles are not oriented paral- able alkynes 10a–b (Scheme 2). The clicked derivatives 11a–
lel to these planes but are significantly tilted. In this way, b and 12a–b were obtained in good yields. The structures
the PhCN molecules within one layer are oriented antipar- of compounds 11a–b and 12a–b were confirmed by their
allel with respect to the PhCN molecules of the neighboring 1H and 13C NMR spectra as well as by mass spectrometry.
layer. It is thus believed that the tilt of the pillar[6]arene Inspection of the 1H NMR spectra indicates the disappear-
cores results from interlayer dipole-dipole interactions. ance of the CH2 azide signal at δ = 3.67–3.50 ppm (see the
Within the layers, it can be noted that the pillar[6]arene mo- Supporting Information). IR data also confirmed that no
lecules are organized in a hexagonal lattice (Figure 1, c). azide residues (2089 cm–1) remain in the final products (see
Even though the tilted orientation of the macrocycles pre- the Supporting Information). Importantly, the 1H NMR
vents optimal overlap of the aromatic subunits, the estab- spectra of 11a–b and 12a–b show the typical singlet of the
lishment of notable intermolecular π–π interactions be- 1,2,3-triazole unit at δ = 7.8–7.9 ppm (see the Supporting
tween neighboring macrocycles is clearly observed.
Information).
Figure 1. (a) ORTEP plot of the structure of 6·(PhCN)2 (thermal
ellipsoids are shown at 50% probability level; C: gray; O: black,
Br: pale gray; N: dark gray, H: white). (b) Stacking within the
6·(PhCN)2 lattice showing successive a/b/aЈ/bЈ layers (view down
the crystallographic a axis; the H atoms and the PhCN molecules
are omitted for clarity). (c) Stacking within the 6·(PhCN)2 lattice
revealing the hexagonal packing of the pillar[6]arene molecules
within one layer (view down the crystallographic b axis; H are omit-
ted for clarity).
The clickable pillar[5]- and pillar[6]arene building blocks
7[16] and 8 were obtained by reaction of 5 and 6, respec-
tively, with sodium azide in N,N-dimethylformamide
(DMF) at room temperature (Scheme 1). Similarly, treat-
ment of 4 with NaN3 afforded 9, the precursor of 1. Owing
to the high number of azide residues, compounds 7–9 were
handled with special care: upon evaporation, these poly-
azides were not dried under high vacuum and the use of
metallic spatula was strictly avoided. Furthermore, these
compounds were always prepared on small scales
(Ͻ500 mg).
Scheme 2. Model CuAAC reactions from the pillar[n]arene build-
ing blocks 7 and 8. Reagents and conditions: (i) CuSO4·5H2O, so-
dium ascorbate, CH2Cl2/H2O, room temp. (11a: 60%; 11b: 88%;
12a: 84%; 12b: 78%).
The functionalization of 7 and 8 with terminal alkynes
under the typical copper-catalyzed alkyne-azide cycload-
dition (CuAAC) conditions used for the functionalization
The reaction conditions used for the preparation of 11a–
of multi-azide cores[3] (CuSO4·5H2O, sodium ascorbate, b and 12a–b were then applied to the mesomorphic subunit
CH2Cl2/H2O) was first attempted from commercially avail- 15 (Scheme 3). Compound 15 was prepared by esterifica-
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5

Job/Unit: O30356
/KAP1
Date: 29-04-13 10:47:17
Pages: 11
J. Barberá, R. Deschenaux, J.-F. Nierengarten et al.
FULL PAPER
tion of 6-heptynoic acid (14) with alcohol 13 using 4-(di- Table 1. Thermal properties of compounds 1–3 and 15 deduced
from the POM and DSC investigations.
methylamino)pyridinium p-toluenesulfonate (DPTS) and
Compd. Phase transition[a][b]
Temp.
[°C][b]
Enthalpy changes ΔH
N,NЈ-dicyclohexylcarbodiimide (DCC). A mixture of 7
(1 equiv.), 15 (11 equiv.), CuSO4·5H2O (0.1 equiv.) and so-
dium ascorbate (0.3 equiv.) in CH2Cl2/H2O (1:1) was vigor-
ously stirred at room temperature for 24 h. After work-up
and purification by column chromatography on SiO2 fol-
lowed by gel permeation chromatography (Biobeads SX-1,
CH2Cl2), 2 was obtained in 81% yield. Similarly, reaction
of polyazide 8 with alkyne 15 gave pillar[6]arene derivative
3 in 90% yield. Finally, model compound 1 was obtained
in 91% yield from 9 and 15. The structures of compounds
1–3 were confirmed by IR, 1H and 13C NMR spectroscopy,
and by mass spectrometry. For all these compounds, the 1H
NMR spectra revealed one set of signals for the peripheral
[kJmol–1]
1
IǞSmA
SmAǞCr
(Tg: 32 °C); SmAǞI
(Tg: 28 °C); SmAǞI
CrǞSmA
SmAǞN
NǞI
149
125
201
209
114
156
158
5.8
119
53
60
64
0.5
0.1
2
3
15
[a] Cr: crystalline solid; SmA: smectic A phase; N: nematic phase;
I: isotropic liquid, Tg: glass transition temperature. [b] Tempera-
tures are given as the onset of the peak obtained during the second
heating run. Tg values are determined during the first cooling run.
mesogenic moieties thus showing that they are all equiva- (114–156 °C) and nematic (156–158 °C) phases. Compari-
lent, in agreement with the symmetrical structures of com- son of the thermal behavior of 1 and 15 reveals interesting
pounds 1–3 (see the Supporting Information).
features. Model compound 1 was isolated in a crystalline
form, suggesting favorable intermolecular π-π interactions
between the central aromatic parts of neighboring mole-
cules. As a consequence of the strong intermolecular π-π
interactions, the crystalline phase is stabilized and only a
monotropic mesophase could form.
By linking together five or six linear subunits through a
central macrocyclic pillar[n]arene core, the liquid-crystalline
properties changed dramatically. Indeed, pillar[n]arene de-
rivatives 2 and 3 gave rise to a broad enantiotropic smectic
A phase (focal-conic fan texture and homeotropic areas, see
the Supporting Information). Moreover, both 2 and 3 were
obtained as glassy products and not as crystalline solids.
Clearly, when compared with model compound 1, crystalli-
zation is prevented by the macrocyclic structures linking the
linear dimeric substructures. At the same time, the broad
enantiotropic mesophases observed for 2 and 3 show that
the macrocyclic core plays an important role regardless of
its shape, i.e., pentagonal vs. hexagonal. It appears that the
observed effect is not related to the fivefold symmetry of
the central scaffold but is a general macrocyclic effect.[17]
To gain further understanding of this effect, high-tem-
perature XRD measurements were carried out on the me-
sophases of cyclopentameric (2) and cyclohexameric (3)
compounds and of precursor 15. A full angular range 2θ
= 1–40° was recorded and, for comparative purposes, the
experiments were carried out in the three cases at the same
temperature (130 °C). XRD measurements of the meso-
phase of 1 could not be performed due to its monotropic
Scheme 3. Preparation of compounds 1–3. Reagents and conditions:
(i) DCC, DPTS, CH2Cl2, 0 °C to room temp. (91%);
(ii) CuSO4·5H2O, sodium ascorbate, CH2Cl2/H2O, room temp. (1:
91%; 2: 81%; 3: 90%).
Liquid-Crystalline Properties
The liquid-crystalline and thermal properties of com- character and tendency to crystallize.
pounds 1–3 and 15 were investigated by polarized optical
The X-ray patterns of the three compounds are consis-
microscopy (POM), differential scanning calorimetry tent with a smectic A phase, as they contain a small-angle
(DSC), and X-ray diffraction (XRD). Their thermal prop- sharp maximum and a large-angle diffuse band. The sharp
erties are summarized in Table 1.
maximum is related to the layer order and from its angular
On heating, model compound 1 melted at 145 °C from position it is possible to deduce the interlayer spacing by
the crystalline state into the isotropic liquid. The formation using Bragg’s law. The diffuse band arises from the lateral
of a monotropic smectic A phase (focal-conic fan texture, interferences between conformationally disordered hydro-
see the Supporting Information) was observed during the carbon chains and denotes the absence of positional order
cooling run followed by crystallization of the sample. In of the mesogenic units within the layers.
contrast, the corresponding monomer 15 gave rise to an
Table 2 collects the spacing deduced from the XRD ex-
enantiotropic behavior with the observation of smectic A periments for each compound. For 15, the experimental
6
www.eurjoc.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O30356
/KAP1
Date: 29-04-13 10:47:17
Pages: 11
Macrocyclic Effects in Pillar[5]- and Pillar[6]arenes
value (50 Å) is larger than the molecule length estimated mation of 2 and 3 is about 100 Å (Figure 2, b). Two conclu-
from stereomodels for a fully-extended conformation (45 Å; sions arise from these results: (i) it is clear that some kind
Figure 2, a). A segment of 21 Å of that length corresponds of interdigitation between molecules in neighboring layers
to the rigid mesogenic unit and 24 Å corresponds to the takes place and that this reduces the effective layer thick-
hydrocarbon chains. However, the hydrocarbon chains are ness; (ii) the small-angle X-ray maximum corresponds to
known not to be in their most-extended conformation in the second order layer reflection and thus the actual layer
the mesomorphic state, and therefore the actual length of thickness is twice the value directly deduced from Bragg’s
the molecule must be shorter than the theoretical value of law, that is 56 Å. This behavior in XRD has been previously
45 Å. To account for the experimental value of 50 Å, the reported and is related to the existence of some peculiarities
molecules must adopt some kind of bilayer arrangement. in the supramolecular arrangement (see below).
This can be achieved if the molecules in the smectic layers
Interdigitation in the mesophases of 2 and 3 must be a
adopt an alternating antiparallel orientation, so that the ali- consequence of the particular molecular features of these
phatic regions are interpenetrated (Figure 2, a). It is prob- mesomorphic compounds, in which the macrocyclic struc-
able that additional interdigitation takes place between ad- ture must provide a large space to accommodate the mesog-
jacent layers due to the dipole–dipole interactions between enic units of the upper and lower layers. Considering that
the terminal cyano groups, a phenomenon described pre- the mesogenic units in the pillar[n]arenes are able to mutu-
viously.[18]
ally interpenetrate as described above for compound 15, a
fully-interdigitated structure can be proposed for the smec-
tic layers of 2 and 3. This high degree of interdigitation
means that the mesogenic units of one particular layer are
interpenetrated beyond the mesogenic units of the adjacent
layer and are embedded in the aliphatic region of this adja-
cent layer (Figure 2, b).
Table 2. Structural data of compounds 2, 3 and 15 deduced from
the XRD measurements.
Compd. Temp. Mesophase Measured spacing Layer thickness
[°C]
[Å]
[Å]
2
3
15
130
130
130
SmA
SmA
SmA
28
28
50
56
56
50
The effective layer thickness estimated for the proposed
structure can be as short as 58 Å (the molecule length,
100 Å, less twice the mesogenic unit length, 21 Å). Con-
sidering an additional shortening due to the conformational
freedom of the aliphatic chains, which would reduce the
effective periodicity to 56 Å, this is consistent with the ob-
servation of the second order reflection at 28 Å. The ab-
sence of the first order reflection may be related to the exis-
tence of a modulation of the electron density wave with a
period equal to half the layer periodicity. Indeed, in the
structure proposed for the smectic A phase of 2 and 3, there
are two maxima of the electron density along the normal
to the layers, one of which corresponds to the macrocycles
and the second corresponding to the interdigitated meso-
genic units. The two regions are mutually spaced by half
the full layer thickness. The same phenomenon has been
described for side-chain polymers[19] and dendritic sys-
tems[20] with liquid crystal properties and is accounted for
by the confinement of the polymer backbones or dendritic
cores in a thin sublayer, thus producing an electron density
maximum comparable to that of the mesogenic units. It is
interesting to note that no differences are found between
the supramolecular arrangement of 2 and 3. It can be con-
cluded that in both compounds a high degree of interpen-
etration between adjacent layers produces a good space fill-
ing and yields an efficient lateral arrangement of the mesog-
enic units in the SmA structure.
Figure 2. (a) Theoretical molecule length of 15 and postulated ar-
rangement in the SmA phase. (b) Theoretical molecule length of 2
and postulated arrangement in the SmA phase; a similar organiza-
tion is also postulated for 3.
Conclusions
For compounds 2 and 3, the experimentally-measured
spacing was 28 Å. This value is too low for the layer thick-
We have described the synthesis of pillar[5]arene 2 and
ness, taking into account that these molecules are much pillar[6]arene 3, bearing ten and twelve mesomorphic sub-
longer than molecules of 15. Indeed the molecule length units, respectively. A broad enantiotropic mesophase has
estimated with stereomodels for the fully-extended confor- been evidenced for both macrocyclic compounds. The spe-
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
7

Job/Unit: O30356
/KAP1
Date: 29-04-13 10:47:17
Pages: 11
J. Barberá, R. Deschenaux, J.-F. Nierengarten et al.
FULL PAPER
Compound 7: A mixture of 5 (370 mg, 0.22 mmol) and NaN3
(172 mg, 2.64 mmol) in DMF (10 mL) was stirred for 24 h at room
temperature under Ar, then H2O (45 mL) was added. The aqueous
layer was extracted with Et2O (3ϫ). The combined organic layers
were washed with water, dried with MgSO4, filtered, and concen-
trated. Column chromatography (SiO2; CH2Cl2) gave 7[16] (278 mg,
97%) as a colorless solid that was used as received in the next step.
Caution: Owing to its high number of azide residues, this compound
must be handled with special care. Upon evaporation, compound 7
has never been dried under high vacuum and the use of metallic spat-
cific orientation of the cyanobiphenyl moieties attached on
both rims of the macrocyclic core forces the system to
adopt a supramolecular organization in which each smectic
layer is interdigitated with its two neighboring layers. In this
way, the mesophase is stable over a broad temperature
range, which explains the macrocyclic effect observed for 2
and 3 when compared with model compounds 1 or 15. Fi-
nally, it can be noted that pillar[n]arene derivatives are chi-
ral. The present work paves the way for the preparation of
optically pure derivatives with ferroelectric liquid crystalline ula should be avoided. Furthermore, this compound has always been
1
prepared on a small scale. IR (neat): ν = 2089 (N ) cm–1. H NMR
˜
properties. Work in this direction is underway in our
laboratories.
3
(CD2Cl2, 300 MHz): δ = 6.94 (s, 10 H), 4.11 (t, J = 6 Hz, 20 H),
3.82 (s, 10 H), 3.67 (t, J = 6 Hz, 20 H) ppm.
Compound 8: A mixture of 6 (295 mg, 0.146 mmol) and NaN3
(133 mg, 2.05 mmol) in DMF (10 mL) was stirred for 24 h at room
temperature under Ar, then H2O (50 mL) was added. The aqueous
layer was extracted with Et2O (3ϫ60) and the combined organic
layers were washed with water (2ϫ), dried with MgSO4, filtered
and concentrated. Column chromatography (SiO2; CH2Cl2) gave 8
(225 mg, 98%) as a colorless solid that was used as received in the
next step. Caution: Owing to its high number of azide residues, this
compound must be handled with special care. Upon evaporation, com-
pound 8 has never been dried under high vacuum and the use of met-
allic spatula should be avoided. Furthermore, this compound has al-
Experimental Section
General: All reagents were used as purchased from commercial
sources without further purification. Compounds 4[14] and 13[21]
were prepared according to previously reported procedures. Evapo-
ration and concentration were performed at water aspirator pres-
sure and drying in vacuo at 10–2 Torr. Column chromatography
was performed with silica gel 60 (230–400 mesh, 0.040–0.063 mm)
purchased from E. Merck. Thin-layer chromatography (TLC) was
performed on glass sheets coated with silica gel 60 F254 purchased
from E. Merck (visualization by UV light). NMR spectra were re-
corded with a Bruker AC300 or AC400 with solvent peaks as refer-
ence. IR spectra were recorded with a Perkin–Elmer Spectrum One.
Elemental analyses were performed by the analytical service of the
ETH Zürich (Switzerland). MALDI-TOF and ESI mass spectra
were recorded by the analytical service of the School of Chemistry
(Strasbourg, France).
ways been prepared on a small scale. IR (neat): ν = 2089 (N ) cm–1.
˜
3
1H NMR (CD2Cl2, 300 MHz): δ = 6.77 (s, 12 H), 3.99 (t, J = 6 Hz,
24 H), 3.91 (s, 12 H), 3.50 (t, J = 6 Hz, 24 H) ppm.
Compound 9: Prepared as described for 7 starting from 4 (389 mg,
1.2 mmol) and NaN3 (195 mg, 3.0 mmol) in DMF (8 mL). Column
chromatography (SiO2; CH2Cl2) gave 9 (273 mg, 92%) as a color-
less oil that was used as received in the next step. Caution: Owing
to its high nitrogen content, this compound must be handled with
special care. Upon evaporation, compound 9 has never been dried
under high vacuum and the use of metallic spatula should be avoided.
Furthermore, this compound has always been prepared on a small
Liquid-Crystalline Properties: Transition temperatures (peak transi-
tions) and enthalpies were determined with a differential scanning
Mettler Toledo DSC 1 STAR calorimeter, under N2, at a rate of
10 °C/min. The instrument was calibrated against indium. Optical
studies were conducted with a Zeiss-Axioscope polarizing micro-
scope equipped with a Linkam-THMS-600 variable-temperature
stage. XRD measurements were carried out at high temperatures
using a Pinhole camera (Anton-Paar) operating with a point fo-
cused Ni-filtered Cu-Kα beam. The sample was held in Lindemann
glass capillaries (0.9 mm diameter) heated with a variable-tempera-
ture attachment. The diffraction patterns were collected on a flat
photographic film mounted perpendicular to the X-ray beam.
scale. IR (neat): ν = 2105 (N ) cm–1. 1H NMR (CDCl , 300 MHz):
˜
3
3
δ = 6.88 (s, 4 H), 4.12 (t, J = 5 Hz, 4 H), 3.58 (t, J = 5 Hz,
4 H) ppm.
Compound 15: DCC (1.31 g, 6.36 mmol) was added to a solution of
13 (2.00 g, 4.24 mmol), 14 (640 mg, 5.09 mmol) and DPTS (1.25 g,
4.24 mmol) in anhydrous CH2Cl2 (100 mL) at 0 °C. After 1 h, the
mixture was warmed slowly to room temperature and then stirred
for 24 h at this temperature. The resulting mixture was evaporated
and column chromatography (SiO2; CH2Cl2) followed by precipi-
tation (the sample was dissolved in CH2Cl2 and the resulting solu-
tion added dropwise to MeOH) and filtration gave 15 (2.23 g, 91%)
Compound 5: BF3·Et2O (1.63 g, 11.5 mmol) was added to a stirred
solution of 4 (3.73 g, 11.5 mmol) and paraformaldehyde (1.04 g,
34.5 mmol) in 1,2-dichloroethane (200 mL) at room temperature.
After 3 h, the reaction mixture was concentrated. Column
chromatography (SiO2; cyclohexane/CH2Cl2, 1:1) gave 5 (1.54 g,
40%). The analytical data were identical to those reported in the
literature for compound 5.[14]
1
as a colorless solid. H NMR (CDCl3, 400 MHz): δ = 8.20 (d, J =
9 Hz, 2 H), 7.76 (AAЈXXЈ, JA,X = 9 Hz, 4 H), 7.68 (d, J = 9 Hz,
2 H), 7.38 (d, J = 9 Hz, 2 H), 7.03 (d, J = 9 Hz, 2 H), 4.11 (t, J =
7 Hz, 2 H), 4.10 (t, J = 6 Hz, 2 H), 2.38 (t, J = 7 Hz, 2 H), 2.26
(td, J = 7, 3 Hz, 2 H), 2.00 (t, J = 3 Hz, 1 H), 1.84 (m, 4 H), 1.61
(m, 4 H), 1.53 (m, 2 H), 1.37 (m, 10 H) ppm. 13C NMR (CDCl3,
100 MHz): δ = 173.5, 164.9, 163.7, 151.6, 144.9, 136.7, 132.7, 132.4,
128.4, 127.7, 122.61, 118.9, 114.4, 111.0, 84.0, 68.6, 68.4, 64.5, 33.8,
29.5, 29.45, 29.4, 29.2, 29.1, 28.7, 27.9, 26.0, 25.9, 24.1, 18.2 ppm.
ESI-MS: m/z calcd. for C37H41NO5Na [M + Na]+ 602.29; found
602.7. C37H41NO5 (579.30): calcd. C 76.66, H 7.13, N 2.42; found
C 76.42, H 7.17, N 2.39.
Compound 6: FeCl3 (0.20 g, 1.24 mmol) was added to a stirred solu-
tion of 4 (2.00 g, 6.17 mmol) and paraformaldehyde (926 mg,
30.85 mmol) in CHCl3 (90 mL) at 45 °C. After 72 h, the reaction
mixture was concentrated. Column chromatography (SiO2; cyclo-
hexane/CH2Cl2, 1:1) followed by gel permeation chromatography
(Biobeads SX-1; CH2Cl2) gave 5 (0.31 g, 15%) and 6 (0.62 g, 30%).
Data for 6: Colorless solid. 1H NMR (CD2Cl2, 300 MHz): δ = 6.75
(s, 12 H), 4.14 (t, J = 6 Hz, 24 H), 3.86 (s, 12 H), 3.55 (t, J = 6 Hz,
24 H) ppm. 13C NMR (CD2Cl2, 75 MHz): δ = 150.7, 129.0, 116.2,
69.5, 31.0, 30.9 ppm. MALDI-TOF-MS: m/z calcd. for General Procedure for the Click Reactions: CuSO4·5H2O and so-
C66H73O12Br12 [M + H]+ 2017.12; found 2017.2. C66H72Br12O12· dium ascorbate were added to a mixture of azide 7–9 and the ap-
CH2Cl2: calcd. C 38.30, H 3.55; found C 38.18, H 3.66.
propriate terminal alkyne in CH2Cl2/H2O (1:1). The resulting mix-
8
www.eurjoc.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O30356
/KAP1
Date: 29-04-13 10:47:17
Pages: 11
Macrocyclic Effects in Pillar[5]- and Pillar[6]arenes
ture was vigorously stirred at room temperature under Ar. After
24 h, H2O was added, the aqueous layer was extracted with CH2Cl2
(3ϫ), and the combined organic layers were dried (MgSO4), fil-
tered and concentrated. The product was then purified as outlined
in the following text.
163.7, 152.71, 151.6, 144.8, 136.7, 132.6, 132.3, 128.3, 127.7, 122.6,
121.2, 118.9, 115.8, 114.4, 111.0, 68.4, 67.1, 64.5, 34.0, 29.5, 29.4,
29.3, 29.2, 29.1, 28.6, 26.0, 25.9, 25.3, 24.5 ppm. ESI-TOF-MS: m/z
calcd. for C84H95N8O12 [M + H]+ 1407.7069; found 1407.8.
C84H95N8O12 (1407.71): calcd. C 71.67, H 6.73, N 7.96; found C
71.39, H 6.69, N 7.85.
Compound 11a: Prepared from 7 (166 mg, 0.13 mmol), 10a (146 mg,
1.43 mmol), CuSO4·5H2O (3.3 mg, 0.013 mmol) and sodium as-
corbate (7.9 mg, 0.04 mmol) in CH2Cl2/H2O (1:1, 6 mL). Column
chromatography (SiO2; CH2Cl2 containing 2% methanol) gave 11a
(180 mg, 60%) as a colorless glassy product. 1H NMR (CD2Cl2,
300 MHz): δ = 7.92 (s, 10 H), 7.79 (m, 20 H), 7.38 (m, 20 H), 7.30
(m, 10 H), 6.55 (s, 10 H), 4.72 (m, 10 H), 4.57 (m, 10 H), 4.19 (m,
10 H), 4.05 (m, 10 H), 3.33 (s, 10 H) ppm. 13C NMR (CDCl3,
75 MHz): δ = 149.6, 147.8, 130.6, 129.0, 128.6, 128.3, 125.7, 120.3,
115.7, 67.2, 50.3, 29.7 ppm. ESI-TOF-MS: m/z calcd. for
Compound 2: Prepared from 7 (83 mg, 0.064 mmol), 15 (408 mg,
0.704 mmol), CuSO4·5H2O (2.0 mg, 0.007 mmol) and sodium as-
corbate (4.0 mg, 0.019 mmol) in CH2Cl2/H2O (1:1, 8 mL). Column
chromatography (SiO2; CH2Cl2 containing 2.5% methanol) fol-
lowed by gel permeation chromatography (Biobeads SX-1; CH2Cl2)
gave 2 (369 mg, 81%) as a colorless glassy product. IR (neat): ν =
˜
2226 (CϵN), 1727 (C=O). 1H NMR (CD2Cl2, 300 MHz): δ = 8.04
(d, J = 7 Hz, 20 H), 7.64 (AAЈXXЈ, JA,X = 7 Hz, 40 H), 7.57 (d, J
= 7 Hz, 20 H), 7.53 (s, 10 H), 7.23 (d, J = 7 Hz, 20 H), 6.89 (d, J
= 7 Hz, 20 H), 6.56 (s, 10 H), 4.70 (m, 20 H), 4.20 (m, 10 H), 4.10
(m, 10 H), 3.94 (t, J = 6 Hz, 20 H), 3.91 (t, J = 6 Hz, 20 H), 3.21
(s, 10 H), 2.61 (m, 20 H), 2.19 (m, 20 H), 1.70 (m, 20 H), 1.56 (m,
60 H), 1.37 (m, 20 H), 1.22 (m, 100 H) ppm. 13C NMR (CDCl3,
75 MHz): δ = 173.5, 164.8, 163.7, 151.6, 149.4, 148.0, 144.8, 136.7,
132.6, 132.3, 131.5, 128.3, 127.7, 122.5, 121.3, 121.2, 118.8, 114.4,
111.0, 68.3, 67.1, 64.5, 50.1, 33.9, 29.7, 29.5, 29.4, 29.2, 29.1, 28.9,
28.6, 26.0, 25.9, 25.3, 24.5 ppm. MALDI-TOF-MS: m/z calcd. for
C
135H120N30O10 [M]+ 2320.9804; found 2320.9.
Compound 11b: Prepared from 7 (198 mg, 0.152 mmol), 10b
(221 mg, 1.67 mmol), CuSO4·5H2O (3.8 mg, 0.015 mmol) and so-
dium ascorbate (9.0 mg, 0.046 mmol) in CH2Cl2/H2O (1:1, 8 mL).
Column chromatography (SiO2; CH2Cl2 containing 2% methanol)
gave 11b (350 mg, 88%) as a colorless glassy product. 1H NMR
(CD2Cl2, 300 MHz): δ = 7.83 (s, 10 H), 7.72 (d, J = 7 Hz, 20 H),
6.93 (d, J = 7 Hz, 20 H), 6.57 (s, 10 H), 4.72 (m, 10 H), 4.58 (m,
10 H), 4.19 (m, 10 H), 4.04 (m, 10 H), 3.78 (s, 30 H), 3.36 (s,
10 H) ppm. 13C NMR (CDCl3, 75 MHz): δ = 159.6, 149.5, 147.6,
128.6, 127.0, 123.3, 119.5, 115.6, 114.4, 67.2, 55.2, 50.3, 29.4 ppm.
ESI-TOF-MS: m/z calcd. for C145H140N30O20 [M]+ 2621.086; found
2621.1.
C
425H470N40O60Na3 [M +
3Na]3+ 2389.167; found 2388.8.
C425H470N40O60 (7098.62): calcd. C 71.91, H 6.67, N 7.89; found
C 71.66, H 6.84, N 7.62.
Compound 3: Prepared from 8 (70 mg, 0.045 mmol), 15 (60 mg,
0.59 mmol), CuSO4·5H2O (1.0 mg, 0.005 mmol) and sodium as-
corbate (5.0 mg, 0.014 mmol) in CH2Cl2/H2O (1:1, 14 mL). Col-
umn chromatography (SiO2; CH2Cl2 containing 2.4% methanol)
followed by gel permeation chromatography (Biobeads SX-1;
CH2Cl2) gave 3 (345 mg, 90%) as a colorless glassy product. IR
Compound 12a: Prepared from 8 (77 mg, 0.05 mmol), 10a (66 mg,
0.65 mmol), CuSO4·5H2O (1.3 mg, 0.005 mmol) and sodium as-
corbate (3.0 mg, 0.015 mmol) in CH2Cl2/H2O (1:1, 8 mL). Column
chromatography (SiO2; CH2Cl2 containing 1.6% methanol) gave
12a (114 mg, 84%) as a colorless glassy product. 1H NMR
(CD2Cl2, 300 MHz): δ = 7.91 (s, 12 H), 7.76 (d, J = 7 Hz, 24 H),
7.38 (m, 36 H), 6.55 (s, 12 H), 4.45 (br. s, 24 H), 4.06 (br. s, 24 H),
3.42 (s, 12 H) ppm. 13C NMR (CDCl3, 75 MHz): δ = 150.0, 147.8,
130.5, 128.9, 128.2, 127.8, 125.6, 120.6, 115.5, 67.1, 49.9, 31.0 ppm.
MALDI-TOF-MS: m/z calcd. for C162H144N36O12 [M]+ 2785.177;
found 2785.9.
(neat): ν = 2226 (CϵN), 1726 (C=O). 1H NMR (CD2Cl2,
˜
300 MHz): δ = 8.10 (d, J = 7 Hz, 24 H), 7.71 (AAЈXXЈ, JA,X
=
7 Hz, 48 H), 7.64 (d, J = 7 Hz, 24 H), 7.51 (s, 12 H), 7.29 (d, J =
7 Hz, 24 H), 7.00 (d, J = 7 Hz, 24 H), 6.59 (br. s, 12 H), 4.55 (m,
24 H), 4.12 (m, 24 H), 4.00 (m, 48 H), 3.33 (br. s, 12 H), 2.61 (m,
24 H), 2.26 (m, 24 H), 1.79 (m, 24 H), 1.56 (m, 72 H), 1.44 (m,
24 H), 1.29 (m, 120 H) ppm. 13C NMR (CDCl3, 100 MHz): δ =
173.6, 164.9, 163.7, 151.6, 150.1, 148.0, 144.8, 136.7, 132.7, 132.4,
128.4, 127.7, 122.6, 121.2, 118.9, 114.4, 114.1, 111.0, 68.4, 67.3,
64.6, 49.9, 34.0, 29.5, 29.4, 29.3, 29.2, 29.0, 28.7, 26.1, 26.0, 25.4,
24.6 ppm. MALDI-TOF-MS: m/z calcd. for C510H565N48O72 [M +
H]+ 8519.241; found 8520.5. C510H564N48O72 (8518.23): calcd. C
71.91, H 6.67, N 7.89; found C 71.62, H 6.70, N 7.83.
Compound 12b: Prepared from 8 (73 mg, 0.047 mmol), 10b (81 mg,
0.61 mmol), CuSO4·5H2O (1.3 mg, 0.005 mmol) and sodium as-
corbate (2.8 mg, 0.014 mmol) in CH2Cl2/H2O (1:1, 8 mL). Column
chromatography (SiO2; CH2Cl2 containing 1.5% methanol) gave
12b (115 mg, 78%) as a colorless glassy product. 1H NMR
(CD2Cl2, 300 MHz): δ = 7.81 (s, 12 H), 7.63 (d, J = 7 Hz, 24 H),
6.85 (d, J = 7 Hz, 24 H), 6.51 (br. s, 12 H), 4.46 (m, 24 H), 4.04
(m, 24 H), 3.75 (s, 36 H), 3.38 (s, 12 H) ppm. 13C NMR (CD2Cl2,
75 MHz): δ = 160.0, 150.5, 147.8, 128.3, 127.0, 123.8, 120.3, 115.9,
114.6, 67.6, 55.6, 50.3, 29.8 ppm. MALDI-TOF-MS: m/z calcd. for
C174H168N36O24 [M + H]+ 3146.311; found 3146.0.
X-ray Crystal Structure of Compound 6: Crystals suitable for X-ray
crystal structure analysis were obtained by slow diffusion of hexane
into a CHCl3/PhCN solution of 6. Data were collected at 173 K
with a Bruker APEX-II Duo KappaCCD diffractometer (Mo-Kα
radiation, λ = 0.71073 Å). The structure was solved by direct meth-
Compound 1: Prepared from 9 (72 mg, 0.288 mmol), 15 (418 mg, ods (SHELXS-97) and refined against F2 using the SHELXL-97
0.720 mmol), CuSO4·5H2O (7 mg, 0.029 mmol) and sodium as-
corbate (17 mg, 0.086 mmol) in CH2Cl2/H2O (1:1, 10 mL). Column
chromatography (SiO2; CH2Cl2 containing 1.7% methanol) gave 1
software. The non-hydrogen atoms were refined anisotropically
using weighted full-matrix least-squares on F2. The H-atoms were
included in calculated positions and treated as riding atoms using
SHELXL default parameters. A semiempirical absorption correc-
tion was applied using SADABS in APEX2; transmission factors:
(370 mg, 91%) as a colorless solid. IR (neat): ν = 2226 (CϵN),
˜
1
1725 (C=O) cm–1. H NMR (CD2Cl2, 300 MHz): δ = 8.07 (d, J =
7 Hz, 4 H), 7.67 (AAЈXXЈ, JA,X = 7 Hz, 8 H), 7.61 (d, J = 7 Hz,
4 H), 7.42 (s, 2 H), 7.26 (d, J = 7 Hz, 4 H), 6.93 (d, J = 7 Hz, 4 H),
6.73 (s, 4 H), 4.59 (t, J = 6 Hz, 4 H), 4.20 (t, J = 6 Hz, 4 H), 3.98
Tmin/Tmax = 0.2341/0.3227. Crystallographic data: formula:
C66H72O12Br12·(C7H5N)2 (M = 2222.40 gmol–1); colorless crystal;
0.35ϫ 0.30ϫ 0.25 mm; crystal system: monoclinic; space group
(t, J = 6 Hz, 4 H), 3.96 (t, J = 6 Hz, 4 H), 2.63 (m, 4 H), 2.25 (m, P21/c; a = 13.8558(7) Å; b = 50.521(3) Å; c = 13.5767(7) Å; β =
4 H), 1.75 (m, 4 H), 1.60 (m, 8 H), 1.53 (m, 4 H), 1.41 (m, 4 H), 119.0850(10)°; V = 8305.4(7) Å3; Z = 4; F(000) = 4368; a total of
1.25 (m, 20 H) ppm. 13C NMR (CDCl3, 75 MHz): δ = 173.6, 164.8, 71506 reflections collected; 1.90° Ͻ θ Ͻ 27.97°, 18075 independent
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
9

Job/Unit: O30356
/KAP1
Date: 29-04-13 10:47:17
Pages: 11
J. Barberá, R. Deschenaux, J.-F. Nierengarten et al.
FULL PAPER
Chiara, Chem. Eur. J. 2010, 16, 3833–3841; d) S. Fabritz, D.
Heyl, V. Bagutski, M. Empting, E. Rikowski, H. Frauendorf,
I. Balog, W.-D. Fessner, J. J. Schneider, O. Avrutina, H. Kolnar,
Org. Biomol. Chem. 2010, 8, 2212–2218; e) M. Lo Conte, S.
Staderini, A. Chambery, N. Berthet, P. Dumy, O. Renaudet, A.
Marra, A. Dondoni, Org. Biomol. Chem. 2012, 10, 3269–3277;
f) A. Marra, S. Staderini, N. Berthet, P. Dumy, O. Renaudet,
A. Dondoni, Eur. J. Org. Chem. 2013, 1144–1149.
For examples constructed on a macrocyclic core, see: a) E.-H.
Ryu, Y. Zhao, Org. Lett. 2005, 7, 1035–1038; b) S. P. Bew, P.
Brimage, N. L’Hermite, S. Sharma, Org. Lett. 2007, 9, 3713–
3716; c) J. Morales-Sanfrutos, M. Ortega-Munoz, J. Lopez-Jar-
amillo, J. Hernandez-Mateo, F. Santayo-Gonzales, J. Org.
Chem. 2008, 73, 7768–7771; d) S. Cecioni, S. Faure, U. Dar-
bost, I. Bonnamour, H. Parrot-Lopez, O. Roy, C. Taillefumier,
M. Wimmerova, J.-P. Praly, A. Imberty, S. Vidal, Chem. Eur. J.
2011, 17, 2146–2159.
For selected reviews, see: a) H. C. Kolb, M. G. Finn, K. B.
Sharpless, Angew. Chem. 2001, 113, 2056; Angew. Chem. Int.
Ed. 2001, 40, 2004–2021; b) C. Remzi Becer, R. Hoogenboom,
U. S. Schubert, Angew. Chem. 2009, 121, 4998; Angew. Chem.
Int. Ed. 2009, 48, 4900–4908; c) C. E. Hoyle, C. N. Bowman,
Angew. Chem. 2010, 122, 1584; Angew. Chem. Int. Ed. 2010,
49, 1540–1573; d) G. Franc, A. K. Kakkar, Chem. Soc. Rev.
2010, 39, 1536–1544; e) C. E. Hoyle, A. B. Lowe, C. N. Bow-
man, Chem. Soc. Rev. 2010, 39, 1355–1387.
reflections with 13909 having IϾ2σ(I); 955 parameters; Final re-
sults: R1(F2) = 0.0653; wR2(F2) = 0.1217, Goof = 1.113. CCDC-
923081 contains the supplementary crystallographic data for this
paper. These data can be obtained free of charge from The Cam-
bridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
Supporting Information (see footnote on the first page of this arti-
cle): Spectroscopic data and HPLC traces for the new compounds,
DSC thermograms, and POM pictures of the liquid crystalline de-
rivatives.
[5]
[6]
Acknowledgments
This research was supported by the University of Strasbourg, the
Centre Nationale de la Recherche Scientifique (CNRS), the Span-
ish project CTQ2012-35692, the FEDER founds and the Swiss
National Science Foundation (grant number 200020-140298). I. N.
thanks the Agence National de la Recherche (ANR) and S. G. the
Swiss National Science Foundation for postdoctoral fellowships.
The authors further thank M. Schmitt for the NMR measurements.
[1] K. E. Geckeler, H. Nishide (Eds.), Advanced Nanomaterials,
Wiley-VCH, Weinheim, Germany, 2010.
[7]
[8]
[9]
I. Nierengarten, S. Guerra, M. Holler, J.-F. Nierengarten, R.
Deschenaux, Chem. Commun. 2012, 48, 8072–8074.
[2] For general examples, see: a) L. M. Campos, K. L. Killops, R.
Sakai, J. M. J. Paulusse, D. Damiron, D. E. Drockenmuller,
B. M. Messmore, C. J. Hawker, Macromolecules 2008, 41,
7063–7070; b) A. S. Goldmann, A. Walther, L. Nebhani, R.
Joso, D. Ernst, K. Loos, C. Barner-Kowollik, L. Berner,
A. H. E. Muller, Macromolecules 2009, 42, 3707–3714; c) L.
Nurmi, J. Lindqvist, R. Randev, J. Syrett, D. M. Haddleton,
Chem. Commun. 2009, 2727–2729; d) S. Mischler, S. Guerra,
R. Deschenaux, Chem. Commun. 2012, 48, 2183–2185.
T. Ogoshi, S. Kanai, S. Fujinami, T. Yamagishi, Y. Nakamoto,
J. Am. Chem. Soc. 2008, 130, 5022–5023.
For reviews on pillar[n]arenes, see: a) P. J. Cragg, K. Sharma,
Chem. Soc. Rev. 2012, 41, 597–607; b) M. Xue, Y. Yang, X.
Chi, Z. Zhang, F. Huang, Acc. Chem. Res. 2012, 45, 1294–
1308; c) T. Ogoshi, J. Inclusion Phenom. Macrocyclic Chem.
2012, 72, 247–262.
a) T. Ogoshi, T. Aoki, K. Kitajima, S. Fujinami, T.-a. Yamagi-
shi, Y. Nakamoto, J. Org. Chem. 2011, 76, 328–331; b) D. Cao,
Y. Kou, J. Liang, Z. Chen, L. Wang, H. Meier, Angew. Chem.
2009, 121, 9901; Angew. Chem. Int. Ed. 2009, 48, 9721–9723;
c) Y. Kou, H. Tao, D. Cao, Z. Fu, D. Schollmeyer, H. Meier,
Eur. J. Org. Chem. 2010, 6464–6470; d) Y. Ma, Z. Zhang, X.
Ji, C. Han, J. He, Z. Abliz, W. Chen, F. Huang, Eur. J. Org.
Chem. 2011, 5331–5335; e) T. Boinski, A. Szumma, Tetrahe-
dron 2012, 68, 9419–9422.
[10]
[3] For examples constructed on a fullerene scaffold, see: a) J. Iehl,
R. Pereira de Freitas, B. Delavaux-Nicot, J.-F. Nierengarten,
Chem. Commun. 2008, 2450–2452; b) J. Iehl, J.-F. Nierengarten,
Chem. Eur. J. 2009, 15, 7306–7309; c) P. Pierrat, S. Vand-
erheiden, T. Muller, S. Bräse, Chem. Commun. 2009, 1748–
1750; d) J. Iehl, J.-F. Nierengarten, Chem. Commun. 2010, 46,
4160–4162; e) J.-F. Nierengarten, J. Iehl, V. Oerthel, M. Holler,
B. M. Illescas, A. Muñoz, N. Martín, J. Rojo, M. Sánchez-Nav-
arro, S. Cecioni, S. Vidal, K. Buffet, M. Durka, S. P. Vincent,
Chem. Commun. 2010, 46, 3860–3862; f) P. Compain, C.
Decroocq, J. Iehl, M. Holler, D. Hazelard, T. Mena Barragán,
C. Ortiz Mellet, J.-F. Nierengarten, Angew. Chem. 2010, 122,
5889; Angew. Chem. Int. Ed. 2010, 49, 5753–5756; g) M.
Durka, K. Buffet, J. Iehl, M. Holler, J.-F. Nierengarten, J. Ta-
ganna, J. Bouckaert, S. P. Vincent, Chem. Commun. 2011, 47,
1321–1323; h) S. Cecioni, V. Oerthel, J. Iehl, M. Holler, D. Go-
yard, J.-P. Praly, A. Imberty, J.-F. Nierengarten, S. Vidal, Chem.
Eur. J. 2011, 17, 3252–3261; i) P. Fortgang, E. Maisonhaute, C.
Amatore, B. Delavaux-Nicot, J. Iehl, J.-F. Nierengarten, Angew.
Chem. 2011, 123, 2412; Angew. Chem. Int. Ed. 2011, 50, 2364–
2367; j) J. Iehl, M. Holler, J.-F. Nierengarten, K. Yoosaf, J. M.
Malicka, N. Armaroli, J.-M. Strub, A. Van Dorsselaer, B. Dela-
vaux-Nicot, Aust. J. Chem. 2011, 64, 153–159; k) M. Sanchez-
Navarro, A. Munoz, B. M. Illescas, J. Rojo, N. Martin, Chem.
Eur. J. 2011, 17, 766–769; l) J. Iehl, J.-F. Nierengarten, A. Har-
riman, T. Bura, R. Ziessel, J. Am. Chem. Soc. 2012, 134, 988–
998; m) J. Iehl, M. Frasconi, H.-P. Jacquot de Rouville, N. Re-
naud, S. M. Dyar, N. L. Strutt, R. Carmieli, M. R. Wasielew-
ski, M. A. Ratner, J.-F. Nierengarten, J. F. Stoddart, Chem. Sci.
2013, 4, 1462–1469.
[11]
[12]
M. Holler, N. Allenbach, J. Sonet, J.-F. Nierengarten, Chem.
Commun. 2012, 48, 2576–2578.
a) T. Ogoshi, R. Shiga, M. Hashizume, T.-A. Yamagishi, Chem.
Commun. 2011, 47, 6927–6929; b) H. Zhang, N. L. Strutt, R. S.
Stoll, H. Li, Z. Zhu, J. F. Stoddart, Chem. Commun. 2011, 47,
11420–11422; c) N. L. Strutt, R. S. Forgan, J. M. Spruell, Y. Y.
Botros, J. F. Stoddart, J. Am. Chem. Soc. 2011, 133, 5668–5671;
d) H. Deng, X. Shu, X. Hu, J. Li, X. Jia, C. Li, Tetrahedron
Lett. 2012, 53, 4609–4612; e) I. Nierengarten, K. Buffet, M.
Holler, S. P. Vincent, J.-F. Nierengarten, Tetrahedron Lett.
2013, 54, 2398–2402.
It is known that isolated molecules with point groups dis-
playing fivefold symmetry must reduce their symmetry when
forming crystalline monolayers, see: T. Bauert, L. Merz, D.
Bandera, M. Parschau, J. S. Siegel, K.-H. Ernst, J. Am. Chem.
Soc. 2009, 131, 3460–3461.
Y. Ma, X. Ji, F. Xiang, X. Chi, C. Han, J. He, Z. Abliz, W.
Chen, F. Huang, Chem. Commun. 2011, 47, 12340–12342.
H. Tao, D. Cao, L. Liu, Y. Kou, L. Wang, H. Meier, Sci. China
Chem. 2012, 55, 223–228.
Compound 7 has already been prepared by following another
synthetic route, see: X.-B. Hu, L. Chen, W. Si, Y. Yu, J.-L. Hou,
Chem. Commun. 2011, 47, 4694–4696.
[13]
[14]
[15]
[16]
[4] For examples constructed on a polyhedral oligomeric silses-
quioxane (POSS) scaffold, see: a) Y. Gao, A. Eguchi, K.
Kakehi, Y. C. Lee, Org. Lett. 2004, 6, 3457–3460; b) Z. Ge, D.
Wang, Y. Zhou, H. Liu, S. Liu, Macromolecules 2009, 42,
2903–2910; c) B. Trastoy, M. E. Pérez-Ojeda, R. Sastre, J. L.
[17]
Related stabilization of mesophases has also been observed for
metallomesogens, see: a) K. Binemans, Y. G. Galymetdinov, R.
Van Deun, D. W. Bruce, S. R. Collinson, A. P. Polishchuk, I.
10
www.eurjoc.org
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 0000, 0–0

Job/Unit: O30356
/KAP1
Date: 29-04-13 10:47:17
Pages: 11
Macrocyclic Effects in Pillar[5]- and Pillar[6]arenes
Bikchantaev, W. Haase, A. V. Prosvirin, L. Tinchunira, I. Litvi-
nov, A. Gubajdullin, A. Rakhmatullin, K. Uyttterhoeven, L.
Van Meerlet, J. Am. Chem. Soc. 2000, 122, 4335–4344; b) J.-F.
Eckert, U. Maciejczuk, D. Guillon, J.-F. Nierengarten, Chem.
Commun. 2001, 1278–1279; c) K. Binnemas, K. Lodewyckx,
Angew. Chem. 2001, 113, 248; Angew. Chem. Int. Ed. 2001, 40,
242–244; d) K. Binnemas, C. Gorller-Walrand, Chem. Rev.
2002, 102, 2303–2345.
[19]
[20]
a) P. Davidson, A. M. Levelut, M. F. Achard, F. Hardouin, Liq.
Cryst. 1989, 4, 561–571; b) J. Barberá, L. Giorgini, F. Paris, E.
Salatelli, R. M. Tejedor, L. Angiolini, Chem. Eur. J. 2008, 14,
11209–11221.
S. Frein, F. Camerel, R. Ziessel, J. Barberá, R. Deschenaux,
Chem. Mater. 2009, 21, 3950–3959.
[21] B. Dardel, D. Guillon, B. Heinrich, R. Deschenaux, J. Mater.
Chem. 2001, 11, 2814–2831.
[18] a) G. J. Brownsey, A. J. Leadbetter, J. Phys. Lett. 1981, 42, 135–
140; b) B. Dardel, D. Guillon, B. Heinrich, R. Deschenaux, J.
Mater. Chem. 2001, 11, 2814–2831.
Received: March 8, 2013
Published Online: ᭿
Eur. J. Org. Chem. 0000, 0–0
© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
11