Red and blue liquid-crystalline borondipyrromethene dendrimers

Article abstract of DOI:10.1021/cm503577y

We have designed a series of modular and fluorescent poly(arylester) dendrimers functionalized with cyanobiphenyl subunits and fluorescent borondipyrromethene (Bodipy) dyes. The green emitter is a Bodipy with four methyl groups, and the Bodipy dye possess

Full text of DOI:10.1021/cm503577y

Article
pubs.acs.org/cm
Red and Blue Liquid-Crystalline Borondipyrromethene Dendrimers
Soumyaditya Mula,†,‡ Stephane Frein,# Virginie Russo,# Gilles Ulrich,† Raymond Ziessel,*,†
́
Joaquín Barbera,*,§ and Robert Deschenaux*,#
́
†ICPEES-LCOSA, CNRS, UMR 7515, Ecole de Chimie, Polymer
̀
es, Mater
́
iaux de Strasbourg (ECPM), 25 rue Becquerel, 67087
, Universidad de
Strasbourg, Cedex 02, France
§Departamento de Química Organ
Zaragoza-CSIC, 50009 Zaragoza, Spain
#Institut de Chimie, Universite
de Neuchatel, Avenue de Bellevaux 51, 2000 Neuchatel, Switzerland
́ ̂ ̂
́
ica, Facultad de Ciencias-Instituto de Ciencia de Materiales de Aragon
́
S
* Supporting Information
ABSTRACT: We have designed a series of modular and fluorescent
poly(arylester) dendrimers functionalized with cyanobiphenyl
subunits and fluorescent borondipyrromethene (Bodipy) dyes. The
green emitter is a Bodipy with four methyl groups, and the Bodipy
dye possessing extended conjugation with two methyl and two vinyl
groups acts as a red emitter. The design element of these
architectures relates to a secondary amide linkers interposed between
the conventional Bodipy and the dendrons. The second- and third-
generation dendrimers give rise to nematic and/or smectic A phases,
whereas the first-generation dendrimers show smectic A and C phases or an unidentified mesophase. The novel materials are
highly fluorescent in solution and in the as-obtained powders but not in the mesophase. Dilution of the dendritic dyes with the
nonfluorescent acid dendron in the solid phase shifted the fluorescence to higher energy, and demonstrated the presence of
aggregates in the solid state. Mixing the red and blue materials in a solid phase led to the observation of effective electronic
energy transfer from the red dye to the blue one. Increasing the proportion of the red dye (energy donor) from 1 to 250 molar
with respect to the blue dye (energy acceptor) resulted in the observation of residual emission of the red dye in the solid state
mixture. Increasing the proportion from 1 to 1000 resulted in equal emission in the 540 to 760 nm range.
use of external stimuli (e.g., photon15 or mechanical stress11,16
)
INTRODUCTION
■
might find interesting applications in optoelectronic devices and
sensors. Recently, photoresponsible self-assembly of vesicles
prone by a host−guest azobenzene/β-cyclodextrin interaction,
and dismantled by the trans/cis azo isomerization under
photonic stimulation, has been studied.17 Phosphorescent
liquid-crystalline platinum and iridium complexes18,19 have also
been studied and show the importance of the geometry and space
filling of the chromophore in the packing of the molecules within
the mesophases and on the luminescence properties. Thermo-
tropic luminescent palladium(II) ortho-metallated imine20 or N-
benzoylthiourea complexes,21 and luminescent molybdenum
nanoclusters also exhibit interesting liquid-crystalline proper-
ties.22
We have previously shown that borondipyrromethene dyes
adequately substituted with a 3,5-diacylamidotoluene platform
equipped with two lateral aromatic rings each bearing three
appended aliphatic chains give rise to fluorescent organogels23
and liquid-crystalline materials with columnar organization.24 At
that time, the synthetic procedure was known to prepare 4,4′-
difluoro-4-bora-3a,4a-diaza-s-indacene (F-Bodipy) derivatives
Much attention is devoted to the design of amphiphilic
dendrimers because of their potential applications in nano-
sciences1 and biomedicine.2,3 Contrary to conventional liquid-
crystalline (LC) materials, dendritic platforms tolerate various
functional groups whose shape, molecular volume, and physical
properties can be counterbalanced by the size (generation) of the
dendrimers as well as by the nature of the functional groups
required to favor microsegregation within the mesophases.4
Several modular and self-assembled systems have been reported,
including liquid-crystalline [60]fullerenes,5 ferrocenes,6 [60]-
fullerene-ferrocene dyads,7 diruthenium clusters,8 flat fluorescent
dyes,9 and gold nanoparticles.10 Recently, libraries of amphiphilic
dendrimers carrying monosaccharides (D-mannose and D-
galactose) and disaccharides (D-lactose) in their hydrophilic
parts, have been engineered, and their ligand bioactivity
demonstrated.3
Luminescent liquid-crystalline materials have recently gained
much importance because of their novel and specific utilizations,
such as (i) to tune the mesophase arrangements by photo-
isomerization of specific items (e.g., azo or vinyl functions), (ii)
to favor charge mobility and charge separation along columnar
organization, and (iii) to promote sensing properties in the gel
phase or mesophases.11−14 The introduction of packing changes
in a luminescent self-assembled condensed phase through the
Received: September 29, 2014
Revised: February 24, 2015
© XXXX American Chemical Society
A
DOI: 10.1021/cm503577y
Chem. Mater. XXXX, XXX, XXX−XXX

Chemistry of Materials
Article
Chart 1
Chart 2
a
Scheme 1
a
Reagents and conditions: (i) CH3OCH2CH2OCH2CCMgBr, dry THF, 60 °C, 12 h; (ii) Et3N, H2NCH2CH2NH2, CO, [Pd(PPh3)2Cl2], toluene,
70 °C, 24 h.
(structure A in Chart 1) with red color (λabs about 520 nm) only.
These mesophases display remarkable optolectronic properties
B
DOI: 10.1021/cm503577y
Chem. Mater. XXXX, XXX, XXX−XXX

Chemistry of Materials
Article
a
Scheme 2
a
Reagents and conditions: (i) p-methoxybenzaldehyde, piperidine, toluene, reflux. (ii) CH3OCH2CH2OCH2CCMgBr, dry THF, 60 °C, 12 h. (iii)
Et3N, H2NCH2CH2NH2, CO, [Pd(PPh3)2Cl2], toluene, 70 °C, 24 h.
a
Scheme 3
a
Reagents and conditions: (i) EDCI, DMAP, CH2Cl2, 48 h.
with strong absorption in the visible region, high fluorescence
quantum yields and relatively narrow emission bandwidths with
high peak intensities.9b,25
fluorescence energy transfer from the central red dye to the
external blue dye occurs in solution and in the columnar
phases.25 However, the materials tend to decompose above 200
The recent engineering of blue Bodipy dyes (structures C and
D in Chart 1) constructed from the red dye B (Chart 1) by an
extended divinyl central core opens the doors to the preparation
of liquid-crystalline materials with different colors. We have
exploited this concept by constructing Bodipy dyes with opposite
charges: the blue dye carries an ammonium function while the
red dye is made of two sulfonate anions. The ionic-self-assembly
of these dyes in a 2:1 blue-to-red stoichiometry affords liquid-
crystalline materials with columnar phases in which very efficient
°C, and the isotropic melt could not be reached.
In this account, we report the successful preparation and
characterization of dendritic red and blue liquid-crystalline
materials and demonstrate efficient energy transfer from the red
to blue dyes in the condensed phase prepared by mixing both
materials. However, these materials are not fluorescent in the
mesophases.
C
DOI: 10.1021/cm503577y
Chem. Mater. XXXX, XXX, XXX−XXX

Chemistry of Materials
Article
a
Scheme 4
a
Reagents and conditions: (i) EDCI, DMAP, CH2Cl2, 48 h.
derivatives (Schemes 3 and 4).31 The structures were confirmed
by spectroscopic methods. For example, the IR peaks at 1644 and
3332 cm−1 and the 13C NMR peaks at δ 41.3, δ 42.2, and δ 167.0
ppm confirmed the molecular structure of 6. It was anticipated
that the additional tiny styryl groups in 9 would not change the
basic assembly structure of the liquid crystals obtained from the
same generation of dendrimer and the red dye 6.
The dye 6 was coupled with dendrons 1, 2, or 3 via peptide
coupling reaction using 1-ethyl-3-(3-(dimethylamino)propyl)-
carbodiimide (EDCI) and 4,4′-dimethylaminopyridine (DMAP)
to furnish 10, 11 and 12, respectively (Scheme 3). Coupling of
dye 9 with 1, 2, or 3 yielded 13, 14, and 15, respectively (Scheme
4). The NMR spectra of all compounds contain the characteristic
peaks of the Bodipy and dendron moieties.
Liquid-Crystalline and Thermal Properties. The meso-
morphic and thermal properties were investigated by polarized
optical microscopy (POM) and differential scanning calorimetry
(DSC). All the compounds reported herein show liquid-
crystalline properties. The phase-transition temperatures and
enthalpies are reported in Table 1. By DSC, melting points were
obtained (except for compound 14) during the first heating run
only indicating partial crystalline character of the samples. From
the first cooling run, glass transition temperatures were observed
for compounds 11 and 12.
First-Generation Dendrimers. No typical texture was
obtained for 13 even when the sample was annealed for several
hours near the clearing temperature. Only a birefringent liquid
was observed both on heating and cooling the sample. On
cooling compound 10 from the isotropic liquid, focal-conic fan
RESULTS AND DISCUSSION
■
Materials and Syntheses. The design is based on first-,
second-, and third-generation dendrons bearing a carboxylic acid
function (Chart 2)9b and Bodipy dyes having a flexible amino
function.26 The use of a tiny linker between the dendron and the
dye is required because of the poor nucleophilicity of the meso-
anilino blue dyes,27 which did not allow coupling with dendrons
of different generations. The use of diethylenediamine as a linker
allows Schotten−Baumann cross-linking between the dendrons
and the dyes under mild reaction conditions after activation of
the acid.28
The key Bodipy dyes were prepared as illustrated in Schemes 1
and 2. The red dye 4 was synthesized by the condensation of 2,4-
dimethylpyrrole and p-iodobenzoyl chloride followed by ring
closure with BF3·Et2O.29 The blue dye 7 was synthesized via
Knoevenagel condensation of 4 and p-methoxybenzaldehyde in
concentrated solution and at high temperature.30 Substitution of
both fluorides of 4 and 7 was feasible using the Grignard reagent
of 2,5-dioxaoctyne. The reaction proceeded smoothly and
furnished compounds 5 and 8, respectively. The new peaks at
δ 81.1 and 91.5 ppm for the alkyne carbons in the 13C NMR
spectrum, and a singlet at δ −10.00 ppm in the 11B NMR
spectrum confirmed the formation of 5. Similar characteristic
peaks in the spectrum of 8 were also observed. Then, a Pd
catalyzed carboamidation reaction of 5 and 8 in the presence of a
flux of CO and an excess of ethylenediamine furnished the red
Bodipy 6 and blue Bodipy 9 with primary amine residues which
were necessary for the subsequent coupling with the acid
D
DOI: 10.1021/cm503577y
Chem. Mater. XXXX, XXX, XXX−XXX

Chemistry of Materials
Article
Table 1. Thermal and Liquid-Crystalline Properties with
a
Enthalpy Changes for the Studied Compounds.
b
Tg
Tm
ΔH
T
ΔH
compd (°C) (°C) (kJ mol−1
)
transition
M → I
(°C) (kJ mol−1
)
c
13
10
95
91
35
53
129
105
125
147
149
156
197
199
13
-
SmC → SmA
SmA → I
SmA → N
N → I
13
14
d
6
11
15
12
55
75
89
102
102
56
25
21
SmA → I
SmA → I
SmA → I
14
28
28
a
Tg, glass-transition temperature; Tm, melting point (obtained during
Figure 2. Thermal-polarized optical micrograph of the focal-conic fan
texture displayed by 14 in the smectic A phase at 139 °C.
the first heating run only); M, unidentified mesophase; SmC, smectic
C phase; SmA, smectic A phase; N, nematic phase; I, isotropization
b
temperature. Temperatures are given as the onset of the peaks
Such mesogens have a strong tendency to align parallel one to
each other and give rise to the formation of layers as observed for
various materials, including liquid-crystalline fullerenes,33 pillar-
[n]arenes (n = 5 or 6),34 gold nanoparticles,10b and side-chain
polymers.35−37 Finally, the liquid-crystalline properties observed
for the compounds described herein are in agreement with the
properties obtained in our former study based on liquid-
crystalline borondipyrromethene dyes.9b
c
obtained during the second heating run. With decomposition.
d
Combined enthalpies.
and homeotropic textures were identified that indicated the
formation of the smectic A phase (Figure 1). On further cooling,
X-RAY DIFFRACTION STUDIES
■
X-ray experiments were carried out on materials submitted to a
thermal treatment consisting of heating up the samples into the
isotropic liquid and cooling them down slowly into the
mesophase or mesomorphic glass (room temperature).
The X-ray patterns of compounds 12, 14, and 15 are
consistent with the formation of smectic phases (Figure 3).
Figure 1. Thermal-polarized optical micrograph of the focal-conic fan
texture displayed by 10 in the smectic A phase at 124 °C.
modification of the textures was observed by POM at 105 °C
indicating a phase transition. No typical texture was obtained for
the low-temperature mesophase even after annealing the sample
for several hours. As no transition was observed by DSC for this
modification, this transition is of second order, and suggests a
smectic A-to-smectic C phase transition.
Second-Generation Dendrimers. Nematic (Figure S1 in the
Supporting Information, schlieren texture) and smectic A phases
(Figure 2, focal-conic fan texture) were observed for 14, and a
smectic A phase was obtained for 11. An increase in the clearing
point on going from the first- to the second-generation
dendrimer is observed as a consequence of stronger
intermolecular interactions because of a higher number of
mesogens when the dendrimer generation increases.
Third-Generation Dendrimers. Compounds 15 and 12
displayed smectic A phases that were identified from the
formation of focal-conic fan textures. The latter appeared only
when the samples were annealed several hours near the clearing
point. Compounds 15 and 12 display the highest clearing points
among the materials reported here. The stabilization of
mesophases as a function of the number of mesogens is often
observed for this kind of dendrimers.32
Figure 3. X-ray pattern of 14 recorded at room temperature after
thermal treatment. The sample spontaneously aligned inside the glass
capillary by a wall effect on cooling from the isotropic liquid. The
capillary axis was horizontal and the image shows that the molecules
oriented parallel to the capillary wall yielding a well-aligned pattern.
The patterns contain one or two sharp maxima in the low-angle
region and a diffuse halo in the high-angle region. When there are
two low-angle maxima, their reciprocal spacing ratio is 1:2,
characteristic of a layered structure. The diffuse character of the
high-angle halo is typical of disordered SmA and SmC phases.
The latter phases are difficult to distinguish on the basis of XRD
only, and the determination of the optical textures by POM is a
reliable method to assign the actual type of the mesophases.38
For compounds 13, 11, and 10, the X-ray diffractograms do not
contain sharp maxima but only diffuse scattering is detected (an
illustrative example is shown in Figure S2 in the Supporting
Information).
The liquid-crystalline phases obtained for compounds 10−15
are in agreement with the structure and nature of the
poly(arylester)dendrimers carrying cyanobiphenyl mesogens.
E
DOI: 10.1021/cm503577y
Chem. Mater. XXXX, XXX, XXX−XXX

Chemistry of Materials
Article
Supramolecular Organization. For compound 14, the
pattern contains two low-angle sharp maxima and a high-angle
diffuse halo. Although of relatively weak intensity, low-angle
spots are clearly visible and correspond to the first- and second-
order reflections from the smectic layers. The measured spacing
is 51.4 Å (d001) and 26.0 Å (d002), respectively, and the layer
thickness is deduced by the equation d = (51.4 + 26.0 × 2)/2 =
51.7 Å. This value is reasonable for the size of compound 14
packed in a smectic A phase, and is comparable with the smectic
layer thickness measured on the smectic A phase of the analogous
compound lacking the substituents on the Bodipy ring.9b
For compounds 12 and 15, the results of the XRD studies are
very similar. In both cases, one single low-angle sharp reflection
and a high-angle diffuse band are observed in the patterns taken
on thermally treated samples. As mentioned above, this kind of
pattern is consistent with a smectic phase and is in agreement
with the POM observations. For compound 12, the
experimentally measured spacing is 29 Å. This value cannot
correspond to the layer thickness because it is too small
compared to the length of the molecule. Therefore, the
experimentally observed maximum must be the second-order
reflection (d002), and thus the layer thickness for compound 12 is
58 Å. For compound 15 (d002 = 26 Å, layer thickness =52 Å), the
results are qualitatively similar and the conclusions are the same
as for compound 12. The layer thickness values found for these
two compounds compare well with the smectic layer thickness
measured on the smectic A phase of the analogous compound
that has the same structure as 12 and 15 but lacking the
substituents on the Bodipy ring.9b
The absence of the first-order reflection for the smectic phase
of these two compounds is most likely due to their structures
based on alternating sublayers containing the dendritic core
(including the Bodipy unit) and the mesogenic units. These two
high-generation dendrimers contain eight mesogenic units
statistically oriented in both senses with the dendritic core and
Bodipy units in the middle. This alternating structure, described
for other dendritic systems containing the same mesogenic
units,8a,9b,39 creates a modulation of the electron density with a
period equal to half the full layer thickness. The same
phenomenon was reported for liquid-crystalline side-chain
polymers,40 and was accounted for by the confinement of the
polymer backbones in a thin sublayer with the mesogenic units to
both sides, so that the backbones (the dendritic core in our case)
create an electron density maximum comparable to that of the
mesogenic cores.
Figure 4. Postulated supramolecular organization of third-generation
dendrimers 12 and 15 within the smectic A phase. The interdigitation is
illustrated by the yellow and blue cyanobiphenyl units: the blue units
belong to the dendrimers which are displayed on the drawing, and the
yellow units belong to dendrimers of adjacent layers. Because of the
lypophilicity of the Bodipy core, some of the latter groups can also be
localized in the sublayers containing the mesogenic units.
family 10, 11, and 1241 and at 643 nm for the blue family 13, 14,
and 15,42 characteristic of the Bodipy dyes connected to the
dendrimers. In the UV part of the spectra, the contributions of
the phenyl groups of the dendrimers are observed with a
common hyperchromic shift with increasing the generation of
the dendrimers (Figures 5 and 6). The spectral profile is weakly
sensitive to solvent polarity (THF, dichloromethane, toluene,
dioxane, or DMF) and in keeping with singlet excited states.
Excitation of all compounds in solution in their S0 → S1
transition induces classical emission of the singlet excited state of
the central Bodipy dye. The red compounds emit in solution at
511 nm and the blue dyes at 658 nm with a high quantum yields
(ca. 60% for the red dyes and about 58% for the blue dyes) and a
nanosecond lifetime regime (ca. 4 ns). The low nonradiative rate
(kNR), the short lifetime and the shape of the steady-state
emission are in good agreement with singlet emitters.43 It is
important to mention that the fluorescence was completely
quenched in the mesophase: to generate liquid-crystalline
phases, heating is required, which most likely favors nonradiative
deactivation because of thermal motion enhancement of the
molecules.
Solid state emission of pristine compounds 12 and 15 are
observed at 576 and 775 nm, respectively (Figures 7 and 8). They
are strongly bathochromically shifted and significantly broader
versus the same dyes in fluid solution. These spectral shapes are
consistent with luminescence of emissive aggregates obtained by
stacking the molecules in the solid state (Figures 7 and 8).45
When dyes 12 or 15 are diluted in acid 3 (10% weight), a less
bathochromically shifted emission is observed. In this solid-
solution, the thin and structured emissions observed at 537 and
688 nm, respectively, are likely due to the association of two
molecules forming dimers. Such a behavior has previously been
observed in thin films of OLED devices engineered from Bodipy
dyes.46 The dilution of the dye at the solid state induces an
enhancement of the fluorescence likely due to the formation of
less nonfluorescent aggregates. The solid-state quantum yields
measured using an integration sphere at: (i) 0.10 0.02 for 12 as
pristine solid at λem 576 nm and 0.42 0.10 for 12 dispersed at
The absence of X-ray reflections in the diffractograms of 11
and 10 is surprising at first glance, because these compounds
show smectic phases as revealed by POM, and this type of
mesophases has a long-range interlayer periodicity. However,
this phenomenon is not totally unexpected and in fact such a
behavior was already observed in our former study.9b The
absence of Bragg reflections is accounted for by a poor layering
due to a diffuse interface between the smectic layers. The diffuse
character of the interface finds its origin in the interdigitation of
the cyanobiphenyl units, and this prevents clear diffractograms to
be obtained. However, the compounds for which clear diffraction
peaks were obtained led to a structural model for the
supramolecular organization within the smectic phases (Figure
4).
Spectroscopic Properties and Energy Transfer in the
Condensed Phase. The spectroscopic data of the compounds
in solution are collected in Table 2. In solution, all compounds
show a strong S0 → S1 (π−π*) transition at 500 nm for the red
F
DOI: 10.1021/cm503577y
Chem. Mater. XXXX, XXX, XXX−XXX

Chemistry of Materials
Article
a
Table 2. Spectroscopic Data for the Red and Blue Mesomorphic Compounds
b
c
c
compd
λabs (nm)
ε (× 103 M−1 cm−1
)
λem (nm)
Φf
τs (ns)
kr (× 10−8 s−1
)
knr (× 10−8 s−1
)
10
11
12
13
14
15
502 278
500 277
500 278
643 269
643 276
644 277
83.6 173
76.6 230
75.1 409
122 111
511
511
511
658
658
658
0.60
0.61
0.67
0.58
0.56
0.60
3.77
3.78
4.10
4.63
4.28
4.56
1.59
1.61
1.63
1.25
1.31
1.32
1.06
1.03
0.81
0.91
1.03
0.87
102 240
115 392
a
b
Measured in THF at 25 °C. Determined in THF solution, ca. 5 × 10−7 M, using Cresyl Violet as reference (ϕF = 0.50 in ethanol).44 All ΦF are
c
corrected for changes in refractive index. Calculated using the following equation: kr = ΦF /τF, knr = (1 − ΦF)/τF, assuming that the emitting state is
produced with unit quantum efficiency.
Figure 8. Normalized emission spectra of 15 in 1 × 10−6 M solution in
Figure 5. Absorption spectra of compounds 10 (black trace), 11 (blue
trace), and 12 (red trace) in THF at room temperature.
THF (red trace), in the solid state (blue trace), and in 10% solid solution
in acid 3 (black trace) at 5 × 10−5 molar.
10% in acid 3 at λem 537 nm (Figure 7); (ii) <0.01 for 15 as
pristine solid at λem 775 nm and 0.40 0.10 for 15 dispersed at
10% in acid 3 at λem 688 nm match well the values found in
solution (Table 2; 67% for 12 in solution compared to 42% in the
solid state, and 60% for 15 in solution compared to 40% in the
solid state).
An interesting behavior is observed in the solid-state emission
for the 12/15 mixture with decreasing the proportion of dye 15
(energy acceptor) when excited in the absorption band of dye 12
at 480 nm. With a 1:1 to 1:2 ratio of dyes 15/12, no residual
emission of donor 12 is detected between 530 and 600 nm, but
an intense emission at 736 nm is observed, which is attributed to
the 15-aggregates (vide supra). When the ratio of 15 versus 12 is
progressively reduced to 1:10, a large emission peak clearly
composed of two overlapping emissive bands is observed, leading
to the conclusion that different dye arrangements in the solid
state are obtained under these conditions (Figure 9). By
increasing the dilution process from 1:20 to 1:50, the wavelength
shift is less pronounced and the emission profile resembles the
one obtained above for the solid-solution of 15 diluted in acid 3
at 10% in weight (Figure 8). Interestingly, when the amount of
blue dye is further reduced with respect to the red dye, the energy
transfer process is less efficient as observed by the increase in the
residual emission of the aggregated dye 12 in the 520 to 620 nm
range (Figure 9). For weight proportions of 1 to 1000 (dye 15 to
dye 12), dual emission of the aggregated dye 12, aggregated dye
15, and nonaggregated dye 15 appears clearly (green traces in
Figure 9).
Figure 6. Absorption spectra of compounds 13 (black trace), 14 (blue
trace), and 15 (red trace) in THF at room temperature.
Figure 7. Normalized emission spectra of 12 in 1 × 10−6 M solution in
THF (red trace), in the solid state (blue trace) and in 10% solid solution
in acid 3 (black trace) at 5 × 10−5 molar.
CONCLUSIONS
■
Our studies demonstrate that by judicious design of the dendritic
platform and Bodipy linker liquid-crystalline materials can be
prepared effectively. Because of the nature of the liquid-
crystalline promoters, nematic and disordered smectic phases
G
DOI: 10.1021/cm503577y
Chem. Mater. XXXX, XXX, XXX−XXX

Chemistry of Materials
Article
C35H30BF2IN2O2: C, 61.25; H, 4.41; N, 4.08. Found: C, 60.89; H, 4.12;
N, 3.72.
Typical Procedure for the Grignard Reaction. To a solution of
4,7-dioxaoct-1-yne (234 mg, 2.05 mmol) in dry THF (30 mL) was
added ethylmagnesium bromide (1.71 mL of 1 M THF solution, 1.71
mmol). The mixture was heated at 60 °C during 2 h, cooled to 25 °C,
and transferred via canula to a solution of 4/7 (0.68 mmol) in dry THF
(20 mL). The mixture was stirred at 25 °C until complete consumption
of the starting material was observed by TLC (12 h). Aqueous saturated
NH4Cl (20 mL) was then added into it and the mixture was extracted
with CH2Cl2 (30 mL). The organic layer was washed with water (20
mL) and brine (20 mL), dried, and evaporated. The residue was purified
by column chromatography (flash silica gel, petroleum ether/ethyl
acetate) to furnish 5/8.
Compound 5. Orange powder (303 mg, 70%). IR: 1543, 2882, 2921
cm−1. 1H NMR: δ 1.40 (s, 6H), 2.72 (s, 6H), 3.36 (s, 6H), 3.52−3.56
(m, 4H), 3.64−3.67 (m, 4H), 4.19 (s, 4H), 6.01 (s, 2H), 7.05 (d, J = 8.5
Hz, 2H), 7.81 (d, J = 8.5 Hz, 2H). 13C NMR: δ 15.0, 16.2, 59.1, 59.8,
68.7, 71.9, 91.0, 94.6, 121.8, 129.4, 130.4, 135.3, 138.4, 140.1, 141.0,
155.7. 11B NMR: δ −10.00 (s). EI-MS (m/z, %): 638.3 (M+, 100). Anal.
Calcd For C31H36BIN2O4: C, 58.33; H, 5.68; N, 4.39. Found: C, 58.53;
H, 5.74; N, 4.19.
Compound 8. Blue powder (383 mg, 65%). IR: 1537, 1599, 2835,
2917 cm−1. 1H NMR: δ 1.47 (s, 6H), 3.12−3.18 (m, 4H), 3.21 (s, 6H),
3.49−3.55 (m, 4H), 3.87 (s, 6H), 4.18 (s, 4H), 6.64 (s, 2H), 6.91−7.01
(m, 4H), 7.10−7.19 (m, 4H), 7.58 (d, J = 8.9 Hz, 4H), 7.84 (d, J = 8.5
Hz, 2H), 8.06 (d, J = 16.3 Hz, 2H). 13C NMR: δ 15.1, 55.4, 58.7, 59.4,
68.1, 71.5, 91.5, 94.5, 114.3, 114.4, 118.0, 119.0, 128.8, 128.9, 130.0,
130.7, 131.2, 134.0, 134.4, 135.3, 136.7, 138.1, 140.0, 152.1, 153.0, 160.3.
11B NMR: δ −10.00 (s). EI-MS (m/z, %): 874.6 (M+, 100). Anal. Calcd
For C47H48BIN2O6: C, 64.54; H, 5.53; N, 3.20. Found: C, 64.69; H,
5.23; N, 3.35.
Typical Procedure for the Carboamidation Reaction. A stirred
solution of 5/8 (0.36 mmol), Et3N (1.3 mL), ethylenediamine (1.3 mL),
and [Pd(PPh3)2Cl2] (48 mg, 0.07 mmol) in toluene (13 mL) was heated
at 70 °C under a CO atmosphere until complete consumption of the
starting material. H2O (20 mL) was then added into the mixture and it
was extracted with CH2Cl2 (50 mL). The organic extract was washed
with H2O (20 mL) and brine (20 mL), dried, and concentrated. The
residue was purified by column chromatography (silica gel, CH2Cl2/
EtOH; 80:20) to furnish 6/9.
Compound 6. Red powder (170 mg, 79%). IR: 1547, 1644, 2871,
2925, 3332 cm−1. 1H NMR: δ 1.34 (s, 6H), 2.72 (s, 6H), 3.02 (t, J = 5.6
Hz, 2H), 3.36 (s, 6H), 3.52−3.61 (m, 6H), 3.63−3.68 (m, 4H), 4.20 (s,
4H), 6.00 (s, 2H), 6.98 (t, J = 5.6 Hz, 1H), 7.40 (d, J = 8.3 Hz, 2H), 7.94
(d, J = 8.3 Hz, 2H). 13C NMR: δ 15.0, 16.2, 41.3, 42.2, 59.1, 59.8, 69.0,
71.9, 90.6, 100.5, 121.9, 127.9, 128.8, 129.4, 134.9, 139.1, 140.4, 141.0,
155.7, 167.0. EI-MS (m/z, %): 598.5 (M+, 100). Anal. Calcd For
C34H43BN4O5: C, 68.23; H, 7.24; N, 9.36; Found: C, 68.42; H, 7.51; N,
9.06. Note amino protons (2H) are not observed, probably because of
fast exchange with residual water in the solvent.
Compound 9. Blue powder (177 mg, 59%). IR: 1540, 1598, 2926,
3291 cm−1. 1H NMR: δ 1.37 (s, 6H), 3.00−3.20 (m, 12H), 3.48−3.60
(m, 6H), 3.85 (s, 6H), 4.16 (s, 4H), 6.60 (s, 2H), 6.93 (d, J = 8.2 Hz,
4H), 7.03 (t, J = 5.8 Hz, 1H), 7.07 (d, J = 16.7 Hz, 2H), 7.40 (d, J = 7.8
Hz, 2H), 7.56 (d, J = 8.2 Hz, 4H), 7.96−8.14 (m, 4H). 13C NMR: δ 15.2,
38.9, 41.2, 55.5, 58.9, 59.5, 68.3, 71.6, 91.7, 114.6, 118.2, 119.1, 127.9,
129.0, 129.3, 130.1, 131.3, 134.3, 134.8, 137.1, 139.2, 140.1, 152.3, 160.5,
167.2. EI-MS (m/z, %): 834.8 (M+, 100). Anal. Calcd For
C50H55BN4O7: C, 71.94; H, 6.64; N, 6.71. Found: C, 71.99; H, 6.81;
N, 6.93. Note amino protons (2H) are not observed, probably because
of fast exchange with residual water in the solvent.
Typical Procedure for the Schotten−Baumann Cross-Linking.
A mixture of dendron 1/2/3 (0.06 mmol), dye 6/9 (0.07 mmol), EDCI
(28 mg, 0.15 mmol), and DMAP (18 mg, 0.15 mmol) in CH2Cl2 (70
mL) was stirred at 25 °C until completion of the reaction. The organic
layer was thoroughly washed with H2O (2 × 10 mL), dried (MgSO4),
and concentrated. The crude product was purified by column
chromatography (silica gel, CH2Cl2/MeOH, 100/0 to 99/1) and
crystallized from CH2Cl2/CH3CN to furnish 10-15.
Figure 9. Normalized emission spectra in the solid state of a mixture of
12 (kept constant at 1 molar) and 15 at various ratios, with excitation at
480 nm (filter at 490 nm).
are observed. Interestingly, the pure red and blue materials are
fluorescent in the solid state, forming fluorescent aggregates that
are bathochromically shifted with respect to the same dyes in
solution. Dispersion of the pure materials with the corresponding
nonfluorescent acid enhanced the fluorescence quantum yields
and shifted the fluorescence to higher energies. High efficiency of
energy transfer in the condensed state within films of dyes
bearing large dendrimers is clearly evidenced. However, in the
liquid-crystalline phases, these materials are completely
quenched due to the need of heating of the material.
Nonradiative deactivation often appears in a condensed state
due to nonradiative deactivation channels favored by motion of
the molecules in a hot stage. The role of the dendritic framework
to properly disperse the Bodipy dyes in the solid state avoiding
formation of nonfluorescent aggregates is evidenced, and
quantum yields of about 40% were determined in the solid
state under dispersed conditions at ambient temperature.
EXPERIMENTAL SECTION
■
Synthesis and Characterization of the Compounds. Com-
pound 4. A mixture of 2,4-dimethylpyrrole (1.000 g, 10.50 mmol) and
p-iodobenzoyl chloride (1.370 g, 5.20 mmol) in dry CH2Cl2 (50 mL)
was stirred at 25 °C for 72 h. The mixture was then treated with Et3N
(0.5 mL), and stirred for another hour. Finally, BF3·Et2O (2.29 mL, 13.8
mmol) was added to the mixture and the solution stirred at 25 °C
overnight. The resulting dark mixture was washed with aqueous
saturated NaHCO3 (100 mL), water (50 mL), brine (50 mL) and dried.
Removal of solvent in vacuo followed by column chromatography of the
residue (flash silica gel, petroleum ether/ethyl acetate) furnished 4 (0.76
g, 32%) as a red powder. IR: 1553, 2880, 2927 cm−1. 1H NMR: δ 1.40 (s,
6H), 2.72 (s, 6H), 6.01 (s, 2H), 7.05 (d, J = 8.5 Hz, 2H), 7.81 (d, J = 8.5
Hz, 2H). 13C NMR: δ 14.9, 16.2, 121.8, 129.4, 130.3, 135.2, 138.3, 140.1,
140.9, 155.6. 11B NMR: δ 3.87 (t). EI-MS (m/z, %): 450.06 (M+, 100).
Anal. Calcd for C19H18BF2IN2: C, 50.70; H, 4.03; N, 6.22. Found: C,
50.79; H, 4.17; N, 6.35.
Compound 7. Compound 4 (304 mg, 0.68 mmol), p-methox-
ybenzaldehyde (92 mg, 0.68 mmol) and piperidine (5 mL) were mixed
in toluene (35 mL) and heated under reflux for 3 h. Any water formed
during the reaction was removed azeotropically by means of a Dean−
Stark trap. Then, the solvent was removed under reduced pressure and
the crude product was purified by column chromatography (flash silica
gel, petroleum ether/ethyl acetate) to furnish a blue solid 7 (380 mg,
82%). IR: 1598, 2947 cm−1. 1H NMR: δ 1.48 (s, 6H), 3.86 (s, 6H), 6.62
(s, 2H), 6.92 (d, J = 8.9 Hz, 4H), 7.09 (d, J = 8.3 Hz, 2H), 7.19 (d, J =
16.8 Hz, 2H), 7.55−7.64 (m, 6H), 7.84 (d, J = 8.3 Hz, 2H). 13C NMR: δ
14.9, 55.4, 113.6, 114.3, 117.7, 129.1, 129.5, 130.6, 136.1, 138.2, 160.5.
11B NMR: δ 3.87 (t). EI-MS (m/z, %): 686.1 (M+, 100); Anal. Calcd for:
H
DOI: 10.1021/cm503577y
Chem. Mater. XXXX, XXX, XXX−XXX

Chemistry of Materials
Article
Compound 10. Red powder (100 mg, 80%). IR: 1605, 1724, 2228,
114.5, 114.6, 114.7, 118.2, 119.0, 119.1, 120.4, 120.8, 121.4, 122.7, 127.1,
127.2, 127.8, 128.4, 128.5, 129.0, 129.2, 129.4, 129.9, 130.1, 131.2, 131.3,
132.3, 132.4, 132.7, 132.8, 133.4, 134.2, 134.3, 136.8, 137.8, 140.0, 145.0,
150.7, 151.7, 152.4, 160.5, 163.2, 163.8, 164.2, 164.6, 164.9, 165.0, 165.9,
168.0, 168.3. MALDI-TOF (m/z, %): 3606.2 (M+, 100). Anal. Calcd for
C219H219BN8O37·H2O: C, 73.39; H, 6.22; N, 3.13. Found: C, 73.09; H,
6.45; N, 3.25.
Compound 15. Blue powder (148 mg, 41%). IR: 1602, 1725, 2232,
2858, 2929, 3330 cm−1. 1H NMR: δ 1.34 (m, 52H), 1.46 (m, 32H), 1.79
(m, 24H), 3.20 (s, 6H), 3.52 (m, 14H), 3.86 (s, 6H), 4.03 (m, 26H),
4.17 (s, 6H), 4.35 (m, 32H), 6.61 (s, 2H), 6.96 (d, J = 8.9 Hz, 24H), 7.12
(d, J = 16.1 Hz, 2H), 7.31 (d, J = 8.1 Hz, 24H), 7.45 (d, J = 8.1 Hz, 3H),
7.62 (d, J = 8.6 Hz, 22H), 7.70 (ABq, J = 7.6 Hz, 32H), 7.91 (d, J = 8.1
Hz, 6H), 8.12 (m, 32H), 8.40 (s, 6H), 8.63 (s, 5H), 8.98 (s, 3H). 13C
NMR: δ 14.9, 25.9, 26.0, 28.7, 29.1, 29.3, 29.4, 29.5, 29.5, 55.4, 58.8,
59.5, 65.5, 65.9, 68.2, 68.4, 71.6, 111.0, 114.4, 114.5, 114.6, 118.0, 118.9,
119.0, 121.2, 122.6, 127.0, 127.1, 127.7, 128.4, 128.5, 128.8, 129.3, 129.6,
129.9, 130.0, 130.9, 131.1, 132.4, 132.4, 132.7, 134.2, 136.7, 139.9, 144.9,
150.5, 151.0, 151.6, 152.2, 160.4, 162.9, 163.0, 163.7, 164.8, 164.9, 165.9,
167.8, 168.1. Anal. Calcd for C371H359BN12O65·H2O: C, 73.60; H, 6.01;
N, 2.78. Found: C, 73.53; H, 5.25; N, 2.54.
1
2852, 2924, 3322 cm−1. H NMR: δ 1.26−1.53 (m, 42H), 1.71−1.87
(m, 12H), 2.73 (s, 6H), 3.36 (s, 6H), 3.50−3.58 (m, 4H), 3.61−3.70 (m,
4H), 3.76 (s, 4H), 3.80−4.09 (m, 8H), 4.20 (s, 4H), 4.29−4.40 (m, 6H),
6.00 (s, 2H), 6.96 (d, J = 8.7 Hz, 6H), 7.31 (d, J = 8.7 Hz, 4H), 7.40 (d, J
= 8.3 Hz, 2H), 7.56−7.76 (m, 12H), 7.88 (d, J = 8.3 Hz, 2H), 7.93 (d, J =
8.3 Hz, 2H), 8.05 (d, J = 1.5 Hz, 2H), 8.14−8.17 (m, 8H), 8.59 (t, J = 1.5
Hz, 1H). 13C NMR: δ 14.8, 16.1, 26.0, 28.7, 29.1, 29.2, 29.3, 29.4, 29.5,
30.9, 41.2, 41.3, 58.9, 59.7, 65.5, 65.8, 68.4, 68.6, 71.8, 90.9, 111.0, 114.4,
114.5, 118.9, 120.8, 121.2, 121.8, 122.6, 127.2, 127.3, 127.7, 127.9, 128.3,
128.8, 129.2, 129.8, 132.3, 132.4, 132.7, 133.2, 134.3, 136.7, 137.8, 139.1,
140.3, 140.8, 144.9, 151.2, 151.7, 155.6, 163.8, 163.9, 164.6, 164.9, 165.1,
165.9, 167.8, 167.9. MALDI-TOF (m/z, %): 2114.4 (M+, 100). Anal.
Calcd for C127H137BN6O21·H2O: C, 72.21; H, 6.63; N, 3.98. Found: C,
72.32; H, 6.98; N, 4.12.
Compound 11. Red powder (156 mg, 78%). IR: 1604, 1727, 2227,
1
2854, 2924, 3322 cm−1. H NMR: δ 1.24−1.47 (m, 66H), 1.77−1.85
(m, 20H), 2.73 (s, 6H), 3.35 (s, 6H), 3.50−3.56 (m, 4H), 3.62−3.69 (m,
4H), 3.73 (s, 4H), 3.98−4.06 (m, 12H), 4.19 (s, 4H), 4.29−4.40 (m,
12H), 5.99 (s, 2H), 6.95 (d, J = 8.7 Hz, 10H), 7.29 (d, J = 8.3 Hz, 8H),
7.36 (d, J = 7.9 Hz, 2H), 7.57−7.74 (m, 24H), 7.88 (d, J = 8.3 Hz, 2H),
7.94 (d, J = 8.3 Hz, 2H), 8.04−8.19 (m, 14H), 8.35 (d, J = 1.5 Hz, 2H),
8.63 (t, J = 1.5 Hz, 2H), 8.93 (t, J = 1.5 Hz, 1H). 13C NMR: δ 14.8, 16.2,
26.0, 26.1, 28.7, 29.2, 29.3, 29.4, 29.5, 29.6, 31.0, 41.2, 41.4, 59.0, 59.7,
65.6, 65.9, 68.4, 68.7, 71.8, 91.0, 111.1, 114.5, 114.7, 118.9, 120.4, 121.3,
121.8, 122.6, 127.1, 127.2, 127.7, 127.9, 128.4, 128.5, 128.8, 129.1, 129.2,
129.9, 133.2, 134.2, 136.7, 137.8, 139.2, 140.2, 140.8, 144.9, 150.7, 151.7,
151.8, 155.7, 163.1, 163.8, 164.2, 164.5, 164.8, 164.9, 165.9, 167.9, 168.1.
MALDI-TOF (m/z, %): 3370.0 (M+, 100). Anal. Calcd for
C203H207BN8O35·H2O: C, 73.83; H, 6.29; N, 3.35. Found: C, 72.54;
H, 6.61; N, 3.40.
ASSOCIATED CONTENT
* Supporting Information
■
S
Techniques, instruments, and analytical data of the new
compounds. This material is available free of charge via the
Internet at http://pubs.acs.org/.
AUTHOR INFORMATION
Corresponding Authors
*E-mail: ziessel@unistra.fr.
■
Compound 12. Red powder (185 mg, 53%). IR: 1606, 1725, 2230,
2850, 2936, 3331 cm−1. 1H NMR: δ 1.32 (m, 80H), 1.78 (m, 40H), 2.73
(s, 6H), 3.36 (s, 6H), 3.54 (m, 4H), 3.66 (m, 4H), 3.74 (s, 4H), 4.03 (m,
22H), 4.20 (s, 6H), 4.37 (m, 20H), 6.00 (s, 2H), 6.96 (d, J = 8.9 Hz,
18H), 6.98 (d, J = 8.1 Hz, 3H), 7.28 (d, J = 8.6 Hz, 18H), 7.38 (d, J = 8.1
Hz, 3H), 7.61 (d, J = 8.6 Hz, 20H), 7.70 (ABq, J = 7.6 Hz, 38H), 7.92 (d,
J = 8.1 Hz, 6H), 8.13 (m, 33H), 8.41 (s, 6H), 8.64 (s, 5H), 8.98 (s, 3H).
13C NMR: δ 14.8, 16.1, 25.9, 26.0, 28.7, 29.2, 29.3, 29.4, 29.5, 29.6, 59.0,
59.7, 65.9, 68.4, 68.6, 71.8, 111.0, 114.4, 114.6, 118.9, 121.2, 121.8,
122.6, 127.0, 127.2, 127.7, 127.8, 128.4, 128.5, 128.8, 129.2, 129.8, 131.4,
132.4, 132.7, 136.7, 140.8, 140.8, 150.5, 150.6, 155.6, 162.9, 163.7, 164.2,
164.4, 164.8, 164.9, 165.9, 167.8, 168.1. MALDI-TOF (m/z, %): 5816.2
(M+, 100). Anal. Calcd for C355H347BN12O63·H2O: C, 73.28; H, 6.05; N,
2.89. Found: C, 73.69; H, 6.51; N, 3.15.
*E-mail: jbarbera@unizar.es.
*E-mail: robert.deschenaux@unine.ch.
Present Address
‡S.M. is currently at Bio-Organic Division, Bhabha Atomic
Research Centre, Mumbai 400085, India
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
R.D. thanks the Swiss National Science Foundation (Grants
200020-140298 and 200020-152716) for financial support. J.B.
thanks the MINECO, Spain, for financial support under the
project CTQ2012-35692, which included FEDER funding. We
Compound 13. Blue powder (71 mg, 51%). IR: 1601, 1722, 2226,
1
2854, 2925, 3301 cm−1. H NMR: δ 1.28−1.49 (m, 42H), 1.72−1.84
(m, 12H), 3.13−3.20 (m, 12H), 3.49−3.55 (m, 4H), 3.72 (s, 4H), 3.85
(s, 6H), 3.99−4.08 (m, 6H), 4.16 (s, 4H), 4.29−4.39 (m, 6H), 6.59 (s,
2H), 6.93−7.00 (m, 10H), 7.10 (d, J = 16.2 Hz, 2H), 7.30 (d, J = 8.3 Hz,
4H), 7.40 (d, J = 7.9 Hz, 2H), 7.56−7.75 (m, 16H), 7.89 (d, J = 8.3 Hz,
2H), 7.94 (d, J = 8.3 Hz, 2H), 8.03−8.17(m, 12H), 8.59 (t, J = 1.5 Hz,
1H). 13C NMR: δ 15.1, 26.1, 28.8, 29.2, 29.3, 29.4, 29.5, 29.6, 41.3, 41.5,
55.5, 58.9, 59.5, 65.6, 65.9, 68.4, 68.5, 71.6, 91.7, 111.1, 114.5, 114.6,
118.2, 119.0, 119.1, 120.9, 121.4, 122.7, 127.2, 127.4, 127.8, 128.0, 128.4,
129.0, 129.4, 129.9, 130.1, 131.2, 132.4, 132.5, 132.6, 132.8, 133.4, 134.3,
136.8, 137.0, 137.8, 139.5, 140.0, 151.2, 151.7, 152.3, 160.5, 163.8, 164.0,
164.7, 164.9, 165.2, 166.0, 167.9. MALDI-TOF (m/z, %): 2350.7 (M+,
100). Anal. Calcd for C143H149BN6O23·H2O: C, 73.13; H, 6.48; N, 3.58.
Found: C, 73.29; H, 6.41; N, 3.65.
acknowledge the CNRS and the Minister
̀
e de l′Enseignement
Superieur de la Recherche for providing research facilities and
́
some financial support. S.M. is very grateful to the French
Embassy in India for the award of a Sandwich-PhD scholarship
and to the Bhabha Atomic Research Center for permission to
conduct research in France. We also thank Delphine Hablot and
Dr. Jean-Hubert Olivier for providing Bodipy Starting materials.
REFERENCES
■
(1) (a) Hosomizu, K.; Imahori, H.; Hahn, U.; Nierengarten, J.-F.;
Listorti, A.; Armaroli, N.; Nemoto, T.; Isoda, S. J. Phys. Chem. C 2007,
111, 2777−2786. (b) Lin, B. F.; Marullo, R. S.; Robb, M. J.; Krogstad, D.
V.; Antoni, P.; Hawker, C. J.; Campos, L. M.; Tirrell, M. V. Nano Lett.
2011, 11, 3946−3950. (c) Tomalia, D. A. New. J. Chem. 2012, 36, 264−
281. (d) Mignani, S.; Majoral, J.-P. New J. Chem. 2013, 37, 3337−3357.
(2) Tekade, R. K.; Kumar, P. V.; Jain, N. K. Chem. Rev. 2009, 109, 49−
87.
Compound 14. Blue powder (108 mg, 50%). IR: 1604, 1727, 2227,
1
2854, 2924, 3322 cm−1. H NMR: δ 1.24−1.51 (m, 66H), 1.72−1.86
(m, 24H), 3.14−3.20 (m, 10H), 3.50−3.54 (m, 4H), 3.75 (s, 4H), 3.85
(s, 6H), 3.98−4.06 (m, 10H), 4.16 (s, 4H), 4.28−4.40 (m, 10H), 6.60 (s,
2H), 6.93−7.01 (m, 12H), 7.10 (d, J = 16.2 Hz, 2H), 7.29 (d, J = 8.5 Hz,
8H), 7.40 (d, J = 8.1 Hz, 2H), 7.56−7.74 (m, 30H), 7.89 (d, J = 8.5 Hz,
2H), 7.95 (d, J = 8.1 Hz, 2H), 8.05−8.23 (m, 16H), 8.35 (d, J = 1.3 Hz,
2H), 8.63 (t, J = 1.3 Hz, 2H), 8.93 (t, J = 1.3 Hz, 1H). 13C NMR: δ 15.1,
26.0, 26.1, 28.8, 29.2, 29.3, 29.3, 29.4, 29.5, 29.6, 31.0, 41.2, 41.5, 55.5,
58.9, 59.5, 65.6, 66.0, 68.3, 68.4, 68.5, 68.6, 71.6, 91.0, 111.0, 111.1,
(3) Percec, V.; Leowanawat, P.; Sun, H.-J.; Kulikov, O.; Nusbaum, C.
D.; Tran, T. M.; Bertin, A.; Wilson, D. A.; Peterca, M.; Zhang, S.; Karnat,
N. P.; Vargo, K.; Moock, D.; Johnston, E. D.; Hammer, D. A.; Pochan, D.
́
J.; Chen, Y.; Chabre, Y. M.; Shiao, T. C.; Bergeron-Brlek, M.; Andre, S.;
I
DOI: 10.1021/cm503577y
Chem. Mater. XXXX, XXX, XXX−XXX

Chemistry of Materials
Article
Roy, R.; Gabius, H.-J.; Heiney, P. A. J. Am. Chem. Soc. 2013, 135, 9055−
9077 and references cited therein.
(4) Roche, C.; Percec, V. Isr. J. Chem. 2013, 53, 30−44.
Jing, A. J.; Jeong, K. U.; Van Horn, R. M.; Sun, B.; Zhu, M.; Kaafarani, B.
R.; Cheng, S. Z. D. J. Phys. Chem. B 2009, 113, 5403−5411. (f) Chen, S.;
Raad, F. S.; Ahmida, M.; Kaafarani, B. R.; Eichhorn, S. H. Org. Lett. 2013,
15, 558−561. (g) Chen, C.-C.; Hinoue, T.; Hisaki, I.; Miyata, M.;
Tohnai, N. Tetrahedron Lett. 2013, 54, 1649−1653.
(5) Selected publications on fullerene-containing liquid crystals:
(a) Lincker, F.; Bourgun, P.; Stoeckli-Evans, H.; Saez, I. M.; Goodby,
J. W.; Deschenaux, R. Chem. Commun. 2010, 46, 7522−7524.
(b) Campidelli, S.; Bourgun, P.; Guintchin, B.; Furrer, J.; Stoeckli-
Evans, H.; Saez, I. M.; Goodby, J. W.; Deschenaux, R. J. Am. Chem. Soc.
2010, 132, 3574−3581. (c) Hoang, T. N. Y.; Pociecha, D.; Salamonczyk,
M.; Gorecka, E.; Deschenaux, R. Soft Matter 2011, 7, 4948−4953. (d) Li,
(15) (a) Jin, H.; Zheng, Y.; Liu, Y.; Cheng, H.; Zhou, Y.; Yan, D. Angew.
Chem., Int. Ed. 2011, 50, 10352−10356. (b) Nalluri, S. K. M.; Voskuhl,
J.; Bultema, J. B.; Boekema, E. J.; Ravoo, B. J. Angew. Chem., Int. Ed. 2011,
50, 9747−9751.
(16) Kozhevnikov, V. N.; Donnio, B.; Bruce, D. W. Angew. Chem., Int.
Ed. 2008, 47, 6286−6289.
H.; Hollamby, M. J.; Seki, T.; Yagai, S.; Mohwald, H.; Nakanishi, T.
̈
Langmuir 2011, 27, 7493−7501. (e) Vergara, J.; Barbera,
L.; Ros, M. B.; Sebastian, N.; de la Fuente, R.; Lopez, D. O.; Fernan
G.; Sanchez, L.; Martín, N. Angew. Chem., Int. Ed. 2011, 50, 12523−
12528. (f) Ince, M.; Martínez-Díaz, M. V.; Barbera, J.; Torres, T. J.
́
J.; Serrano, J.
(17) Liu, Y.; Yu, C.; Jin, H.; Jiang, B.; Zhu, X.; Zhou, Y.; Lu, Z.; Yan, D.
J. Am. Chem. Soc. 2013, 135, 4765−4770.
́
́
́
dez,
́
(18) (a) Santoro, A.; Whitwood, A. C.; Williams, J. A. G.; Kozhevnikov,
V. N.; Bruce, D. W. Chem. Mater. 2009, 21, 3871−3882. (b) Spencer,
́
Mater. Chem. 2011, 21, 1531−1536. (g) Mamlouk-Chaouachi, H.;
Heinrich, B.; Bourgogne, C.; Guillon, D.; Donnio, B.; Felder-Flesch, D.
J. Mater. Chem. 2011, 21, 9121−9129. (h) Zhang, X.; Hsu, C.-H.; Ren,
X.; Gu, Y.; Song, B.; Sun, H.-J.; Yang, S.; Chen, E.; Tu, Y.; Li, X.; Yang,
X.; Li, Y.; Zhu, X. Angew. Chem., Int. Ed. 2015, 54, 114−117.
́
M.; Santoro, A.; Freeman, G. R.; Díez, A.; Murray, P. R.; Torroba, J.;
Whitwood, A. C.; Yellowlees, L. J.; Williams, J. A. G.; Bruce, D. W.
Dalton Trans. 2012, 41, 14244−14256.
(19) Prokhorov, A. M.; Santoro, A.; Williams, J. A. G.; Bruce, D. W.
Angew. Chem., Int. Ed. 2012, 51, 95−98.
(i) Lehmann, M.; Hugel, M.; Angew. Chem., Int. Ed. 2015, 54, DOI:
̈
(20) Micutz, M.; Ilis, M.; Staicu, T.; Dumitrascu, F.; Pasuk, I.; Molard,
Y.; Roisnel, T.; Cîrcu. Dalton Trans. 2014, 43, 1151−1161.
(21) Ilis, M.; Micutz, M.; Dumitrascu, F.; Pasuk, I.; Molard, Y.; Roisnel,
T.; Cîrcu, V. Polyhedron 2014, 69, 31−39.
10.1002/anie.201410662.
(6) Review on ferrocene-containing liquid crystals: Kadkin, O. N.;
Galyametdinov, Y. G. Russ. Chem. Rev. 2012, 81, 675−699.
́
(7) Campidelli, S.; Severac, M.; Scanu, D.; Deschenaux, R.; Vazquez,
(22) Cortes, M. A.; Dorson, F.; Prev
́ ̂
ot, M.; Ghoufi, A.; Fontaine, B.;
E.; Milic, D.; Prato, M.; Carano, M.; Marcaccio, M.; Paolucci, F.;
Rahman, G. M. A.; Guldi, D. M. J. Mater. Chem. 2008, 18, 1504−1509.
(8) (a) Frein, S.; Auzias, M.; Sondenecker, A.; Vieille-Petit, L.;
Goujon, F.; Gautier, R.; Cîrcu, V.; Meriadec, C.; Artzner, F.; Folliot, H.;
́
Cordier, S.; Molard, Y. Chem.Eur. J. 2014, 20, 8561−8565.
(23) Camerel, F.; Bonardi, L.; Schmutz, M.; Ziessel, R. J. Am. Chem.
Soc. 2006, 128, 4548−4549.
́
Guintchin, B.; Maringa, N.; Suss-Fink, G.; Barbera, J.; Deschenaux, R.
̈
Chem. Mater. 2008, 20, 1340−1343. (b) Chaia, Z. D.; Rusjan, M. C.;
Castro, M. A.; Donnio, B.; Heinrich, B.; Guillon, D.; Baggio, R. F.;
Cukiernik, F. D. J. Mater. Chem. 2009, 19, 4981−4991. (c) Bottazzi, T.;
Cecchi, F.; Zelcer, A.; Heinrich, B.; Donnio, B.; Guillon, D.; Cukiernik,
F. D. J. Coord. Chem. 2013, 66, 3380−3390.
̀
(24) Camerel, F.; Bonardi, L.; Ulrich, G.; Charbonniere, L.; Donnio,
B.; Bourgogne, C.; Guillon, D.; Retailleau, P.; Ziessel, R. Chem. Mater.
2006, 18, 5009−5021.
́
(25) Olivier, J.-H.; Barbera, J.; Bahaidarah, E.; Harriman, A.; Ziessel, R.
J. Am. Chem. Soc. 2012, 134, 6100−6103.
(9) (a) Chen, Z.; Swager, T. M. Org. Lett. 2007, 9, 997−1000.
(26) Ziessel, R.; Bonardi, L.; Retailleau, P.; Ulrich, G. J. Org. Chem.
2006, 71, 3093−3102.
́
(b) Frein, S.; Camerel, F.; Ziessel, R.; Barbera, J.; Deschenaux, R. Chem.
Mater. 2009, 21, 3950−3959. (c) Kendhale, A. M.; Schenning, A. P. H:
J.; Debije, M. G. J. Mater. Chem. A 2013, 1, 229−232.
(27) Mula, S.; Elliot, K.; Harriman, A.; Ziessel, R. J. Phys. Chem. A 2010,
114, 10515−10522.
́
(10) (a) Donnio, B.; García-Vazquez, P.; Gallani, J.-L.; Guillon, D.;
(28) Kolmakov, K.; Belov, V. N.; Wurm, C. A.; Harke, B.; Leutenegger,
M.; Eggeling, C.; Hell, S. W. Eur. J. Org. Chem. 2010, 3593−3610.
(29) Rousseau, T.; Cravino, A.; Bura, T.; Ulrich, G.; Ziessel, R.;
Roncali, J. Chem. Commun. 2009, 1673−1675.
Terrazi, E. Adv. Matter. 2007, 19, 3534−3539. (b) Mischler, S.; Guerra,
S.; Deschenaux, R. Chem. Commun. 2012, 48, 2183−2185. (c) Yu, C. H.;
Schubert, C. P. J.; Welch, C.; Tang, B. J.; Tamba, M.-G.; Mehl, G. H. J.
Am. Chem. Soc. 2012, 134, 5076−5079. (d) Kanie, K.; Matsubara, M.;
Zeng, X.; Liu, F.; Ungar, G.; Nakamura, H.; Muramatsu, A. J. Am. Chem.
Soc. 2012, 134, 808−811. (e) Lewandowski, W.; Jatczak, K.; Pociecha,
D.; Mieczkowski, J. Langmuir 2013, 29, 3404−3410. (f) Lewandowski,
(30) Ziessel, R.; Bura, T.; Olivier, J.-H. Synlett. 2010, 2304−2310.
(31) El-ghayoury, A.; Ziessel, R. J. Org. Chem. 2000, 65, 7757−7763.
(32) Dardel, B.; Guillon, D.; Heinrich, B.; Deschenaux, R. J. Mater.
Chem. 2001, 11, 2814−2831.
(33) Lenoble, J.; Campidelli, S.; Maringa, N.; Donnio, B.; Guillon, D.;
Yevlampieva, N.; Deschenaux, R. J. Am. Chem. Soc. 2007, 129, 9941−
9952.
(34) (a) Nierengarten, I.; Guerra, S.; Holler, M.; Nierengarten, J.-F.;
Deschenaux, R. Chem. Commun. 2012, 48, 8072−8074. (b) Nierengart-
en, I.; Guerra, S.; Holler, M.; Karmazin-Brelot, L.; Barbera, J.;
́
Deschenaux, R.; Nierengarten, J.-F. Eur. J. Org. Chem. 2013, 3675−3684.
(35) Kawakami, T.; Kato, T. Macromolecules 1998, 31, 4475−4479.
(36) Yamada, M.; Itoh, T.; Nakagawa, R.; Hirao, A.; Nakahama, S.-i.;
Watanabe, J. Macromolecules 1999, 32, 282−289.
(37) Barmatov, E. B.; Filippov, A. P.; Shibaev, V. P. Liq. Cryst. 2001, 28,
511−523.
(38) (a) Cowling, S. J. Optical Microscopy Studies of Liquid Crystals.
In Handbook of Liquid Crystals; Goodby, J. W., Collings, P. J., Kato, T.,
Tschierske, C., Gleeson, H. F., Raynes, P., Eds.; Wiley−VCH:
Weinheim, Germany, 2014; Vol. 1, Chapter 9. (b) Agra-Kooijman, D.
M., Kumar, S. X-ray Investigations of Liquid Crystals. In Handbook of
Liquid Crystals; Goodby, J. W., Collings, P. J., Kato, T., Tschierske, C.,
Gleeson, H. F., Raynes, P., Eds.; Wiley−VCH: Weinheim, Germany,
2014; Vol. 1, Chapter 10.
W.; Constantin, D.; Walicka, K.; Pociecha, D.; Mieczkowski, J.; Gor
E. Chem. Commun. 2013, 49, 7845−7847. (g) Romiszewski, J.;
Puterova-Tokarova, Z.; Mieczkowski, J.; Gorecka, E. New. J. Chem.
2014, 38, 2927−2934. (h) Wolska, J. M.; Pociecha, D.; Mieczkowski, J.;
Gor
́
ecka,
́
́
́
ecka, E. Chem. Commun. 2014, 50, 7975−7978.
(11) Sagara, Y.; Kato, T. Angew. Chem., Int. Ed. 2008, 47, 5175−5178.
(12) Wang, Y.; Chen, Q.; Li, Y.; Liu, Y.; Tan, H.; Yu, J.; Zhu, M.; Wu,
H.; Zhu, W.; Cao, Y. J. Phys. Chem. C 2012, 116, 5908−5914.
(13) (a) Venkatesan, K.; Kouwer, P. H. J.; Yagi, S.; Muller, P.; Swager,
̈
T. M. J. Mater. Chem. 2008, 18, 400−407. (b) Thomas, S. W.; Yagi, S.;
Swager, T. M. J. Mater. Chem. 2005, 15, 2829−2835. (c) Damm, C.;
Israel, G.; Hegmann, T.; Tschierske, C. J. Mater. Chem. 2006, 16, 1808−
1816. (d) Santoro, A.; Whitwood, A. C.; Williams, J. A. G.; Kozhevnikov,
V. N.; Bruce, D. W. Chem. Mater. 2009, 21, 3871−3882.
(14) (a) Hu, J.; Zhang, D.; Jin, S.; Cheng, S. Z. D.; Harris, F. W. Chem.
Mater. 2004, 16, 4912−4915. (b) Leng, S.; Chan, L. H.; Jing, J.; Hu, J.;
Moustafa, R. M.; Van Horn, R. M.; Graham, M. J.; Sun, B.; Zhu, M.;
Jeong, K. U.; Kaafarani, B. R.; Zhang, W.; Harris, F. W.; Cheng, S. Z. D.
Soft Matter 2010, 6, 100−112. (c) Gao, B.; Wang, M.; Cheng, Y.; Wang,
L.; Jing, X.; Wang, F. J. Am. Chem. Soc. 2008, 130, 8297−8306.
(d) Lucas, L. A.; De Longchamp, D. M.; Richter, L. J.; Kline, R. J.;
Fischer, D. A.; Kaafarani, B. R.; Jabbour, G. E. Chem. Mater. 2008, 20,
5743−5749. (e) Leng, S.; Wex, B.; Chan, L. H.; Graham, M. J.; Jin, S.;
́
(39) Campidelli, S.; Lenoble, J.; Barbera, J.; Paolucci, F.; Marcaccio,
M.; Paolucci, D.; Deschenaux, R. Macromolecules 2005, 38, 7915−7925.
J
DOI: 10.1021/cm503577y
Chem. Mater. XXXX, XXX, XXX−XXX

Chemistry of Materials
Article
(40) (a) Davidson, P.; Levelut, A. M.; Achard, M. F.; Hardouin, F. Liq.
́
Cryst. 1989, 4, 561−571. (b) Barbera, J.; Giorgini, L.; Paris, F.; Salatelli,
E.; Tejedor, R. M.; Angiloini, L. Chem.Eur. J. 2008, 14, 11209−11221.
(41) Ziessel, R.; Ulrich, G.; Harriman, A. New J. Chem. 2007, 31, 496−
501.
(42) Ulrich, G.; Ziessel, R.; Harriman, A. Angew. Chem., Int. Ed. 2008,
47, 1184−1201.
(43) Karolin, J.; Johansson, L. B.-A.; Strandberg, L.; Ny, T. J. Am. Chem.
Soc. 1994, 116, 7801−7806.
(44) Olmsted, J., III J. Phys. Chem. 1979, 83, 2581−2584.
(45) Olivier, J.-H.; Widmaier, J.; Ziessel, R. Chem.Eur. J. 2011, 17,
11709−11714.
(46) Bonardi, L.; Kanaan, H.; Camerel, F.; Jolinat, P.; Retailleau, P.;
Ziessel, R. Adv. Funct. Mater. 2008, 18, 401−413.
K
DOI: 10.1021/cm503577y
Chem. Mater. XXXX, XXX, XXX−XXX