Swallow-tail substituted liquid crystalline perylene bisimides: Synthesis and thermotropic properties

Article abstract of DOI:10.1021/ja905260c

Tailor-made synthesis and structure-property relationship of several swallow-tail N-substituted perylene bisimide (PBI) dyes are presented. PBI derivatives were synthesized by two distinct synthetic approaches, the details being evaluated herein. All the PBIs carry either alkyl swallow-tail or oligoethylenglycolether (OEG) swallow-tail moieties as N-substituents, and many of them are unsymmetrically substituted. We avoided substitution at bay positions of the perylene core to maintain the planarity and strong π-π interactions, which favor intermolecular order and charge carrier transport. The thermotropic behavior, which is strongly influenced by the nature of the substituents was investigated using differential scanning calorimetry (DSC), polarization optical microscopy (POM), and X-ray diffraction measurements (XRD). The introduction of OEG swallow-tail units facilitates thermotropic liquid crystalline behavior in most cases and the unsymmetrical substitution allowed the tuning of the mesophase-width. The mesophases exhibit characteristic columnar hexagonal (Colh) packing arising from π-π interactions between cofacially orientated perylene molecules. Thus, the inherent tendency of PBI molecules for crystallization could be effectively suppressed by incorporating flexible OEG swallow-tail units only at imide positions. This molecular design was crucial to obtain liquid crystallinity and intracolumnar long-range order. The substituents did not influence the electronic energy levels such as HOMO and LUMO.

Full text of DOI:10.1021/ja905260c

Published on Web 09/18/2009
Swallow-Tail Substituted Liquid Crystalline Perylene
Bisimides: Synthesis and Thermotropic Properties
Andre´ Wicklein, Andreas Lang, Mathis Muth, and Mukundan Thelakkat*
Department of Macromolecular Chemistry I, Applied Functional Polymers, UniVersita¨t Bayreuth,
UniVersita¨tsstraꢀe 30, 95440 Bayreuth, Germany
Received June 26, 2009; E-mail: mukundan.thelakkat@uni-bayreuth.de
Abstract: Tailor-made synthesis and structure-property relationship of several swallow-tail N-substituted
perylene bisimide (PBI) dyes are presented. PBI derivatives were synthesized by two distinct synthetic
approaches, the details being evaluated herein. All the PBIs carry either alkyl swallow-tail or oligoethyl-
englycolether (OEG) swallow-tail moieties as N-substituents, and many of them are unsymmetrically
substituted. We avoided substitution at bay positions of the perylene core to maintain the planarity and
strong π-π interactions, which favor intermolecular order and charge carrier transport. The thermotropic
behavior, which is strongly influenced by the nature of the substituents was investigated using differential
scanning calorimetry (DSC), polarization optical microscopy (POM), and X-ray diffraction measurements
(XRD). The introduction of OEG swallow-tail units facilitates thermotropic liquid crystalline behavior in most
cases and the unsymmetrical substitution allowed the tuning of the mesophase-width. The mesophases
exhibit characteristic columnar hexagonal (Colh) packing arising from π-π interactions between cofacially
orientated perylene molecules. Thus, the inherent tendency of PBI molecules for crystallization could be
effectively suppressed by incorporating flexible OEG swallow-tail units only at imide positions. This molecular
design was crucial to obtain liquid crystallinity and intracolumnar long-range order. The substituents did
not influence the electronic energy levels such as HOMO and LUMO.
achieved by increased ordering of PBI molecules.12,13 In general,
inducing liquid crystallinity is an elegant way of improving
Introduction
Perylene bisimide1,2 (PBI, perylene tetracarboxylic acid
bisimide) derivatives represent an important class of n-type
semiconductor materials exhibiting a relatively high electron
affinity among large-band gap materials.3-5 PBIs are readily
available inexpensive robust compounds, and they combine high
quantum yields of photoluminescence with excellent photo-
chemical and thermal stability.6,7 PBIs are promising compounds
for application in organic electronic devices.8-11 The solid-state
packing of the perylene bisimides determines the morphology
in thin films, which plays a major role in improving the device
performance. For instance, an increase in exciton diffusion
length and an improvement in charge carrier mobilities can be
supramolecular organization, as it promotes π-π stacking,
allows for dynamic reorganization, and facilitates the processing
of thin films, which is not feasible with highly crystalline
materials.14-17 The unique structural and electronic properties
of especially discotic liquid crystals,18,19 also open completely
different aspects of possible applications in topical research
fields such as molecular electronics and high-efficiency organic
photovoltaics.8,20-22 Most semiconducting discotics are good
hole transporting materials (p-type), while only a limited number
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Swallow-Tail Substituted Liquid Crystalline PBIs
A R T I C L E S
of good electron transporting materials (n-type) have been
reported.23
devices.32,33 A change from alkyl to oligooxyethylene substit-
uents provides higher conformational flexibility of the C-O
bond compared to the C-C bond. Other physical properties,
such as optical or redox properties should not be affected by
N-substitution, as the nodes in the HOMO and LUMO at the
imide nitrogen reduce electronic coupling of the perylene
bisimide core and the imide substituents to a minimum.34 This
is extremely advantageous if only the thermotropic properties
of PBIs should be tailored without altering the electronic
properties.
For this purpose, three different types of N-substitution
patterns were studied (Scheme 1): type I with a symmetric
substitution pattern, utilizing different alkyl or OEG swallow-
tail substituents. This approach is used to study the influence
of substituents with different spatial requirements or polarity
on thermotropic behavior of symmetrically N-substituted PBIs.
Type II uses an unsymmetrical substitution pattern comprising
different alkyl swallow-tail substituents in combination with
OEG swallow-tail or alkyl swallow-tail with distinct spatial
demands. Here an asymmetric substitution is used to study the
impact of asymmetry of the substitution profile on thermotropic
behavior. Type III consists of unsymmetrical substitution pattern,
utilizing swallow-tail in combination with linear alkyl or OEG
substituents. Here the influence of a reduction of branched
swallow-tail substituents to linear ones is investigated.
In general, the self-assembly process of PBI in bulk is a
complex balance between molecular stacking arising from π-π
interaction of the perylene core moiety and the flexible nature
of appropriate side chains. Thus an optimum balance of rigidy
and flexibility that is crucial for inducing liquid crystallinity
has to be found. For electronic device applications, the side
chains also should be favorably small, so that the dilution of
the electronically active perylene moiety with the electronically
inactive, insulating side groups is minimal. Hence, a compromise
between active chromophore content and side groups that
influence the morphology has to be met.
To the best of our knowledge, all of the thermotropic liquid
crystalline perylene bisimide derivatives reported in literature
are symmetrically substituted. Cormier and Gregg report on
liquid crystalline PBIs with branched propylimid-oligo(oxyeth-
ylene) or phenethylimide-oligo(oxyethylene) side-chains.24,25
Pioneering work of Wu¨rthner and co-workers involves columnar
hexagonal PBIs, with tridodecylphenyl or tridodecyloxyphenyl
substituents, also in combination with perylene bay substitu-
tion.26,27 Other reports on symmetrically substituted liquid
crystalline PBIs deal with tridodecyloxy gallic acid substituted
derivatives6,28 and PBIs with simple aliphatic chains.3 Very
recently Mu¨llen et al. reported on cooperative molecular motion
phenomenon within a symmetrically substituted PBI exhibiting
liquid crystalline properties.29 It has been observed that for
various phthalocyanines and triphenylenes, an unsymmetrical
substitution pattern broadens the mesophase and strongly
influences liquid crystalline packing.20,30,31 But this has not been
studied in the case of PBIs. In fact there are no unsymmetrically
N-substituted liquid crystalline PBIs published up to date and
therefore, this substitution pattern is also investigated here.
A fundamental question here is, how to efficiently weaken
the strong degree of crystallinity which is inherent in PBIs using
a suitable synthetic strategy for unsymmetrical N-substitution.
We report here our successful approach of swallow-tail N-
substitution employing oligoethylenglycol units (OEG) to ac-
complish this goal. Thus we report for the first time a systematic
study on the effect of an asymmetric N-substitution pattern of
PBIs on the thermotropic behavior. The present approach is
aimed at understanding the molecular design requirements to
introduce liquid crystalline phases in PBIs without any bay
substitution. It can be expected that by introducing two swallow-
tail N-side chains having different spatial dimensions and
additionally different polarities, the thermotropic behavior of
PBIs may be tailored. Furthermore, alkyl swallow-tail groups
are well-known to induce high solubility in perylene bisimides
which allows for the fabrication of solution-processable
Results And Discussion
Synthesis. An overview of the synthesized PBIs 1 to 11 is
given in Scheme 1 and the respective synthetic pathway in
Scheme 2. The synthesis of PBIs 1-11 is based on perylene-
3,4,9,10-tetracarboxylic dianhydride PTCDA as starting material.
Generally two different synthetic strategies are feasible for
asymmetric N-substitution of PBIs (Scheme 2, Route A and B).
The common method consists of the condensation of monoim-
ides 12 as key intermediates with some primary amine to
unsymmetrical PBIs (Route A).35,36 Generally, condensation
reaction of the dianhydride PTCDA with excess of primary
amines in molten imidazole or quinoline and zinc acetate as
Lewis acid catalyst exclusively allows access to symmetrical
bisimides (1-4) in high yields but not to key monoimide
intermediates 12. Even substoichometric amounts of amines
usually result in the formation of symmetric bisimides and
unreacted perylene dianhydride PTCDA. Likewise, the utiliza-
tion of a mixture of primary amines provides a mixture of two
symmetric and one unsymmetric perylene bisimide that is hardly
to separate.35 Nagao and Misono depict a partial saponification
of the symmetric bisimides to monoimides 12 with conc.
sulphuric acid at high temperatures.37,38 On the other hand,
Langhals describes a partial saponification under strong basic
conditions with KOH in t-BuOH as reaction medium.35 In the
following, we prepared PBIs 1-4 and 6-9 using Route A, by
saponification of bisimides with KOH and subsequent conden-
sation with a second amine. Additionally a microwave-assisted
(23) Chesterfield, R. J.; McKeen, J. C.; Newman, C. R.; Ewbank, P. C.;
da Silva Filho, D. A.; Bredas, J.-L.; Miller, L. L.; Mann, K. R.; Frisbie,
C. D. J. Phys. Chem. B 2004, 108, 19281–19292.
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11006.
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2001, 7, 2245–2253.
(32) Langhals, H.; Ismael, R.; Yu¨ru¨k, O. Tetrahedron 2000, 56, 5435–
5441.
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2007, 13, 450–465.
(33) Langhals, H.; Demmig, S.; Potrawa, T. J. Prakt. Chem. 1991, 333,
733–748.
(28) Jancy, B.; Asha, S. K. Chem. Mater. 2008, 20, 169–181.
(29) Hansen, M. R.; Schnitzler, T.; Pisula, W.; Graf, R.; Mu¨llen, K.; Spiess,
H. W. Angew. Chem., Int. Ed. 2009, 48, 4621–4624.
(30) Clarkson, G. J.; Cook, A.; McKeown, N. B.; Treacher, K. E.; Ali-
Adib, Z. Macromolecules 1996, 29, 913–917.
(34) Langhals, H.; Demmig, S.; Huber, H. Spectrochim. Acta A 1988, 44A,
1189–1193.
(35) Kaiser, H.; Lindner, J.; Langhals, H. Chem. Ber. 1991, 124, 529–
535.
(36) Langhals, H.; Saulich, S. Chem. Eur. J. 2002, 8, 5630–5643.
(37) Nagao, Y.; Misono, T. Dyes Pigm. 1984, 5, 171–188.
(38) Nagao, Y.; Misono, T. Bull. Chem. Soc. Jpn. 1981, 54, 1191–1194.
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9
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A R T I C L E S
Wicklein et al.
Scheme 1. Overview of Symmetrically and Unsymmetrically N-Substituted Perylene Bisimides (PBIs) Classified According to the Nature of
Respective Substituentsa
a PBIs were prepared either by synthetic route A or B.
Scheme 2. Main Synthetic Pathways for Unsymmetrical N-Substitution of Perylene Bisimidesa
a (i) Imidazole, Zn(OAc)2, 2-4 h, 160 °C; (ii) KOH, t-BuOH, 90°C 1-1.5 h; (iii) DMAc, Zn(OAc)2, 20 min, 160 °C, 200 W; (iv) 1. KOH, 2. AcOH;
(v) NH4OH, K2CO3; (vi) DMF, K2CO3, KI, 80 °C, 3-5 d; (vii) DMF, NaH, 80 °C, 48 h. Route A: 1-4 and 6-9; Route B: 5, 10 and 11.
method for the condensation reaction of monoimide monoan-
hydride 12 with amines was also developed.
moiety allows for condensation reactions with amines in a first
step, whereas the imide moiety offers the possibility for
introduction of a second N-substituent via nucleophilic substitu-
tion SN2 under basic conditions with alkylhalides in a second
An alternative method (Route B) makes use of imide
anhydride 13 as asymmetric building block.39,40 The anhydride
9
14444 J. AM. CHEM. SOC. VOL. 131, NO. 40, 2009

Swallow-Tail Substituted Liquid Crystalline PBIs
A R T I C L E S
step. Thus Route B employing asymmetric synthon 13 to attain
asymmetric N-substituted PBIs was pursued as synthetic strategy
for PBIs 5, 10 and 11.
side chain amine in the bisimide hydrolysis step. Additionally
the comparatively mild reaction conditions (<60 °C) for the
nucleophilic substitution allow for introduction of N-substituents
that are unstable at higher temperatures. A high level of purity
was achieved for all PBI compounds by repeated column
chromatography purification until they all showed a single
chromatogram in gel permeation chromatography (GPC).
All PBIs were fully characterized by means of 1H, 13C NMR
spectroscopy, IR, GPC, MS and Microanalyses. These PBIs can
be regarded as a closed chromophoric system due to the nodes
of the HOMO and LUMO orbitals at imide nitrogens.34
Accordingly, the PBIs under investigation with different sub-
stituents show identical absorption behavior. The UV-vis
spectra of these compounds in very dilute solutions exhibit the
characteristic fingerprint vibronic fine structure of PBI with
peaks at about 525, 490, 460, and 430 nm respectively. In order
to elucidate the electronic energy levels which determine the
energy and electron transfer processes, and the reversibility of
redox processes, cyclic voltammetry (CV) was used. CV is a
common method for studying electrochemical behavior and to
evaluate the relative HOMO and LUMO levels using ferrocene
as internal calibration. PBIs possess good electron affinity and
so they are easy to be reduced and rather difficult to be oxidized.
All PBIs investigated herewith, exhibit two reversible reduction
peaks. In order to calculate the absolute values of HOMO and
LUMO levels, the redox data was calibrated with respect to
ferrocene-ferrocenium couple Fc/Fc+, which has a quasi-
calculated HOMO-energy level of 4.8 eV.50 The LUMO energy
levels of PBIs were obtained from the half-wave reduction
potentials. However, the oxidation potentials of most compounds
were not observed in the CV measurements window up to +1
V vs Ag/AgNO3. Hence the HOMO levels of PBIs were
estimated from the optical band gap and the LUMO levels. The
optical band gaps of all PBIs were determined from the
absorption edge of absorption spectra of diluted solutions. Thus,
all compounds exhibit a LUMO of about -3.8 eV and a HOMO
value of -6.0 eV with respect to the zero energy level. As
expected the differences in electronic properties are negligible
for these substitution patterns. This is due to the electronic
decoupling of the perylene bisimide core and the imide
substituents.34
All the required linear and swallow-tail amines and halides
were prepared according to conventional synthetic methods
already reported in literature. Alkyl swallow-tail amines were
accessible by reductive amination of the corresponding ketones
with ammonia and NaBH3CN as reducing agent in high
yields.41,42 Alkyl swallow-tail bromide was synthesized by
bromination of the respective alcohol, which was obtained by
a double grignard reaction of the respective alkyl bromide with
ethyl formiate.43 OEG swallow-tail amines were derived by a
4 step sequence: OEG swallow-tail secondary alcohols were
prepared according to reported procedures,44,45 converted to the
corresponding tosylates46,47 and then transformed to the azides
by nucleophilic substitution.48 The azides were finally reduced
by LiAlH4 to the corresponding amines. Linear oligooxyethyl-
ene-bromides were obtained by bromination of the respective
alcohol according to literature procedure.49
The symmetrically substituted PBIs 1-4 (Type I) were
synthesized by simple conversion of perylene dianhydride
PTCDA with the respective swallow-tail amine (Route A first
step). This well-established method allows for high yields of
the bisimide products. Due to swallow-tail substituents, the
bisimides obtained are highly soluble. For an unsymmetrical
substitution, to obtain type II derivatives, the disubstituted PBIs
1 and 2 were partially hydrolyzed to the monoimide monoan-
hydrides 12a, b respectively by treatment with an excess KOH
in t-BuOH. Finally these unsymmetrical alkyl swallow-tail OEG
swallow-tail PBIs 6, 7, 8 and 9 were obtained by conversion of
the respective monoimide monoanhydrides (12a or 12b) with
the respective OEG swallow-tail amine. The intermediate 12a
was converted to 6 and 7, whereas 12b resulted in 8 and 9. For
this synthetic step, microwave irradiation conditions were
applied. Under microwave conditions, the reaction time could
be reduced drastically from 4 h to 20 min and high yields were
generally obtained (for example, 96% for PBI 6). On the other
hand, unsymmetrically substituted PBIs 5, 10 and 11 were
obtained via the asymmetric building block 13 according to
Route B. After condensation reaction of 13 with the respective
alkyl swallow-tail amine, the second substituent was introduced
via nucleophilic substitution using the respective bromide in a
subsequent step to get 5, 10 and 11. Both synthetic routes allow
for satisfactory yields of the final unsymmetrical PBI products,
described under type II and III. The advantage of Route B is
that it is straightforward and there is no unnecessary loss of
In the following, a detailed study of the structure-property
relationship of the different substitution patterns type I-III with
respect to thermotropic liquid crystalline behavior is presented.
This elucidates the structural requirements for inducing liquid
crystalline phases in PBIs.
Thermal and Thermotropic Properties. The thermal stability
of the PBIs was analyzed by means of thermogravimetric
analysis (TGA) under nitrogen atmosphere. All compounds are
stable up to 300 °C (Table 1). Thermotropic behavior of the
different derivatives was investigated by a combination of
differential scanning calorimetry (DSC) and polarization optical
microscopy (POM). Additionally the molecular order within
observed mesophases was determined using X-ray diffraction
studies (XRD). The TGA data and phase transition temperatures
with associated enthalpy values obtained from DSC for all PBIs
discussed herein are summarized in Table 1. The DSC data was
obtained at a scanning rate of 10 K min-1 unless indicated
otherwise. The first heating cycles of DSC were neglected to
exclude influences of the thermal history of the samples.
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2002, 18, 952–954.
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(45) Vacus, J.; Simon, J. AdV. Mater. 1995, 7, 797–800.
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Liq. Cryst. Sci. 2000, 338, 75–97.
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699.
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38, 1673–1678.
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A R T I C L E S
Wicklein et al.
Table 1. Summary of the Thermal Behaviour, Phase Transitiona Temperatures with Corresponding Transitions Enthalpies and Mesophases
of Investigated PBIs 1-11 (Obtained from TGA and DSC)
phase transitions and corresponding enthalpies ∆H (in parentheses) °C/(kJ mol-1
2 heating cycle 1 cooling cycle
)
b
PBI
Tdec °C
Type I
1
2
3
4
5
6
332.9
296.2
323.5
325.4
329.0
314.6
339.3
323.1
318.7
324.9
334.9
Cr 133.2 (19.5) f I
I 118.3 (-5.0) f Colh 110.7 (-11.6) f Cr
I 59.3(-6.2) f Cr2 27.2 (-5.2) f Cr1
I 141.7 (-3.3) f Colh 39.8 (-1.8) f Cr2 21.9 (-3.7) f Cr1
I 121.1 (-3.7) f Colh
Cr1 53.8 (6.9) f Cr2 76.8 (6.6) f I
Cr1 78.2 (15.8) f Colh 145.8 (3.5) I
Cr 67.8 (24.0) f Colh 126.9 (3.9) f I
Cr 98.8 (8.5) f I
Cr 77.6 (14.8) f Colh 154.4 (3.9) f I
Cr 65.5 (15.0) f Colh 148.7 (5.9) f I
Cr 51.0 (10.7) f Colh 107.7 (3.0) f I
Cr 54.3 (12.1) f Colh 111.8 (3.3) f I
Cr 140.1 (10.6) f I
Type II
I 36.3 (-3.7) f Cr
I 146.1 (-3.8) f Colh
7
I 142.0 (-5.7) f Colh 1.7 (-2.2) f Cr
I 105.0 (-2.9) f Colh 23.5 (-7.6) f Cr
I 102.1 (-3.3) f Colh 1.6 (-3.2) f Cr
I 129.3 (-10.6) f Cr
8c
9
Type III
10
11
Cr 151.8 (14.3) f I
I 142.0 (-14.0) f Cr
a Cr ) crystal phase; Colh ) columnar hexagonal mesophase; I ) isotropic. b Temperature represents 5% weight loss in TGA measurements at a
c
heating rate of 10 K min-1 under nitrogen atmosphere. Measured for a heating and cooling rate at 2.0 K min-1
.
Transition from an isotropic liquid to crystalline or liquid
crystalline phases can be monitored by the evolution of
characteristic textures. Additionally, liquid-crystalline phases are
anisotropic fluids which in general are optically birefringent.
The characteristic textures of liquid crystalline materials result
not only from the symmetry-dependent elasticity of the liquid-
crystalline phase in combination with defects and surface
conditions,18 but also from thickness and cooling rate of the
sample, under investigation. Optical polarization microscopic
textures for all the compounds are consistent with the phase
transition behavior observed in DSC. All unsymmetrical PBIs
carrying one alkyl swallow-tail and one OEG swallow-tail
exhibit thermotropic liquid crystalline behavior. In contrast, a
reduction of the branched substituents to linear ones results in
materials without mesophase bahviour. The evidence of a
hexagonal ordered stacking (Colh) with a high order in the
individual columns, was supported by XRD-measurements. The
influence of the three different substitution patterns of PBIs
under investigation in type I-III are discussed individually in
the following paragraphs.
Thermotropic Behavior of Type I, PBIs 1-4. DSC thermo-
gramms of type I PBIs are summarized in Figure 1. In literature
there is a controversial discussion, if symmetrically substituted
1 exhibits liquid crystalline behavior.51-53 It could be shown
here, that the symmetrical molecule 1 carrying alkyl substituents
exhibits a narrow monotropic hexagonal columnar Colh me-
sophase upon cooling from the isotropic melt at 118.3 °C with
a phase-width of only 8 °C and crystallizes upon further cooling
at 110.7 °C. The evidence of a Colh ordering was confirmed by
polarization microscopy, here typical focal conic textures can
be observed under crossed polarizers (Figure 2a). Also a
Figure 1. DSC thermograms of symmetrical type I PBIs 1, 2, 3 and 4
showing the second heating and first cooling cycle at a heating rate of 10
K min-1 with respective transition temperatures (°C). Red curves represent
the second heating cycle and blue curves represent the first cooling cycle.
a simple increase in substituent length does not help to increase
the mesophase temperature-width of compound 1, but even
results in crystalline behavior.
symmetrical analogue 2 with longer alkyl chains (R1
)
-C11H23), shows two phase transitions upon heating, and cooling
cycle. But here, the first transition in cooling cycle corresponds
to a crystallization process that cannot be attributed to a liquid
crystalline phase as evidenced by polarization microscopy,
where needle-like crystalline aggregates are formed upon
annealing the sample at 61 °C (Figure 2b). The second transition
at 27 °C corresponds to a crystalline-crystalline transition, but
no difference in the optical texture can be observed here. Hence
On the other hand, a change from alkyl swallow-tail to OEG
swallow-tail substituents in case of PBIs 3 and 4, results in liquid
crystalline behavior. This can be attributed to the higher
conformational freedom of the C-O bond compared to C-C
bond allowing for a better space filling around the discotic
mesogen. In contrast to symmetrical dialkyl swallow-tail PBI
1, the compounds 3 and 4 have a much broader liquid crystalline
phase which is not monotropic. Additionally, the length of the
OEG swallow-tail substituent influences the clearing temperature
of PBIs (3: Tiso ) 145.8 °C; 4: Tiso ) 126.9 °C). As expected
compound 4 with longer OEG substituent exhibits a lower
(51) Pisula, W.; Kastler, M.; Wasserfallen, D.; Robertson, J. W. F.; Nolde,
F.; Kohl, C.; Muellen, K. Angew. Chem., Int. Ed. 2006, 45, 819–823.
(52) Marcon, V.; Kirkpatrick, J.; Pisula, W.; Andrienko, D. Phys. Status
Solidi 2008, 245, 820–824.
clearing temperature, whereas the enthalpy ∆HCol fiso remains
(53) Hansen, M. R.; Graf, R.; Sekharan, S.; Sebastiani, D. J. Am. Chem.
Soc. 2009, 131, 5251–5256.
h
almost the same. The transition temperature from the crystalline
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Swallow-Tail Substituted Liquid Crystalline PBIs
A R T I C L E S
Figure 2. Optical microscopic images of textures of PBIs type I (under
crossed polarizers) of (a) 1 annealed in the mesophase at 118 °C showing
typical focal conic texture of Colh phase, (b) long needle-like crystals of 2
at 61.2 °C, (c) 3 in mesophase at 144 °C showing dendritic growth
aggregates of Colh phase and (d) 4 at 142 °C showing fan-shaped focal
conic textures. The textures were obtained upon cooling the sample from
the isotropic phase and annealing at the respective temperatures slightly
above phase-transition temperature.
phase to the liquid crystalline phase Cr f Colh is shifted only
slightly from 78.2 °C for 3 to 67.8 °C for 4. But here the
enthalpy of the melting process to the liquid crystalline phase
is with 24.0 kJ mol-1 for 4 much higher than 15.8 kJ mol-1 for
3. In the heating cycle, the LC phase-width is 68 °C for 3 and
59 °C for 4, and in the cooling cycle the LC phase-width for 3
is with 102 °C larger, due to supercooling of crystallization.
For PBI 4, the crystallization transition upon cooling cycle could
not be detected in DSC (10 K min-1), but here XRD-
measurements at RT showed typical multiple crystalline reflec-
tions. Also the texture observed in POM was not shearable at
room temperature anymore. Transition from an isotropic liquid
to columnar hexagonal mesophase (Colh) for both 3 and 4 was
observed in POM as indicated by the formation of typical
dendritic growth aggregates or fan-shaped focal conic textures
upon cooling the sample from the isotropic melt under crossed
polarizers (Figure 2c, d). The straight linear defects observed
in several textures are also characteristic for an ordered columnar
mesophase.18,19 These textures are highly shearable in the
mesophase range and no crystallization was observed upon
cooling, only the viscosity of the LC-phase increases upon
cooling to room temperature. For 3 an additional crystalline-
crystalline transition at 22 °C can be observed upon cooling
the sample in DSC. For this transition no textural changes could
be observed in polarization microscopy and X-ray scattering
experiments could not be performed at temperatures below room
temperature, but the XRD-pattern at room temperature showed
multiple reflections typical for a crystalline material. Due to
the high viscosity of the mesophase the crystallization is
supercooled in DSC (even at slow scanning rates) and partial
recrystallization occurs for both materials upon heating the
sample again. In short, a simple increase in the alkyl substituent
length does not result in liquid crystalline behavior, but a change
in the nature of the substituent from alkyl to OEG helps to
induce liquid crystallinity in the case of symmetrically substi-
tuted swallow-tail PBI of type I.
Figure 3. DSC thermograms of unsymmetrical type II PBIs 5, 6, 8, 9 (10
K min-1) and 7 (2 K min-1) showing the second heating and first cooling
cycle with respective transition temperatures (°C). Red curves show the
second heating cycle and blue curves represent the first cooling cycle.
Thermotropic Behavior of Type II, PBIs 5-9. DSC thermo-
grams of type II PBIs are summarized in Figure 3. The
unsymmetrical compound 5 carrying two different alkyl swal-
low-tail substituents remains crystalline. Also a comparison of
1, 2 and 5 clearly shows that the LC-phase observed in 1 could
not be broadened in 2 or 5, both by extending the length of
substituents or by introducing unsymmetrical substitution.
However, the unsymmetrical PBIs with one OEG swallow-tail
substituent and one alkyl swallow-tail substituent (6-9) resulted
in thermotropic liquid crystalline derivatives. Moreover, in the
unsymmetrical molecules 6-9, an increase in alkyl chain length
has only a marginal influence in decreasing the clearing
temperature, whereas a corresponding increase in OEG length
decreases the clearing temperature considerably. Thus for
instance 6 with two oxyethylene repeating units clears at 154.9
°C and 7 carrying three oxyethylene repeating units shows a
clearing temperature of 108.5 °C; a difference of 46 °C.
Similarly compound 8 with a shorter OEG substituent clears at
148.4 °C compared to 9 carrying a longer OEG substituent at
111.8 °C, the difference being 37 °C. Thus the clearing
temperature can be tuned by appropriate substituent length.
Generally the transition from Colh phase to crystalline phase is
strongly supercooled here and recrystallization could be ob-
served upon heating cycles. The crystallization processes can
be observed more clearly at a heating rate of 2 K min-1. The
effect of supercooling, for example observed in 6, 8 or 9, allows
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A R T I C L E S
Wicklein et al.
Figure 4. Optical microscopic images of textures of PBIs 5-9 (under crossed polarizers) of (a) crystals of 5 fromed upon annealing at 63 °C, (b) texture
of 6 at 153 °C showing dendritic growth snowflake-like aggregates of Colh phase but also ribbons with straight linear defects that are characteristic for
ordered columnar mesophases, (c) 7 at 108 °C showing spherulitic texture with maltese crosses of Colh phase, (d) 8 at 141 °C showing large spherulitic
texture of Colh phase formed upon fast cooling from isotropic melt and (e) 8 large dendritic growth aggregates of Colh phase formed upon annealing at 149
°C. (f) 8 annealed at 149 °C at different film region showing dendritic growth agreggates, here a λ/4 plate is utilized to visualize partial homeotropic
ordering, (g) PBI 9 annealed in the mesophase at 108 °C showing typical dendritic-growth aggregates of the Colh phase and (h) 9 sheared-film at same film
position. The textures were obtained upon cooling the sample from the isotropic phase and annealing at the respective temperatures slightly above phase-
transition temperature.
for freezing in the mesophase. This finding is of great relevance
when these PBIs are employed in electronic devices.
and occurs at 36 °C (Figure 3). Also the crystallization process
of 5 upon annealing at 63 °C can be observed in POM (Figure
4a). On the other hand PBI 6 exhibits Colh mesophase which
can be attributed to the presence of OEG substituent. Thus, the
introduction of two different alkyl swallow-tail substituents with
different spatial demands does not result in liquid crystalline
behavior. In contrast, in 6, employing a combination of alkyl
swallow-tail substituents with OEG swallow-tail substituents,
broad liquid crystalline mesophases can be observed (77 °C
mesophase window in the heating cycle). In short, the com-
parison of 5 and 6 clearly indicates the ability of ether
substituents to suppress the crystallization tendency of the
perylene bisimide moiety.
Thermotropic Behaviour of Type III, PBIs 10 and 11. A
reduction of the size of the N-substituents is of fundamental
interest in designing PBI semiconductors for device applications
in order to keep the content of the electronically active perylene
chromophore high. To this end, one of the swallow-tail
substituents was replaced with a linear one in type III com-
pounds. Thus unsymmetrical PBIs 10 and 11 with one swallow-
tail and one linear substituent were synthesized. Both 10 and
11 are crystalline materials as can be seen from DSC-
thermograms (Figure 5) and POM textures (Figure 6a, b). PBI
10 melts at 140 °C whereas 11 shows a melting peak at 152
°C. Both compounds recrystallize on cooling and do not exhibit
any supercooling effect. The absence of any mesophase indicates
that the linear substituents are spatially less demanding and may
not be able to fill the space sufficiently around the columnar
stacked PBI molecules.
For these PBIs 6-9 the evidence of Colh liquid crystalline
behavior was further confirmed by POM (Figure 4). The
unsymmetrical type II PBIs 6-9 carrying one OEG swallow-
tail substituent show characteristic Colh textures. Figure 4a
depicts the crystalline texture of PBI 5 which does not exhibit
any liquid crystalline behavior. In contrast, for PBI 6, large
snowflake-like dendritic-growth aggregates of Colh phase as well
as ribbons with straight linear defects that are characteristic for
ordered columnar mesophases can be observed at 153 °C (Figure
4b). Figure 4c represents the texture of 7 at 108 °C showing
spherulitic textures with maltese crosses, also typical for a Colh
ordering. Figure 4d shows compound 8 at 141 °C showing large
spherulitic textures of Colh phase formed upon fast cooling from
isotropic melt, whereas extremely large dendritic aggregates of
the Colh phase are formed upon annealing 8 at 149 °C (Figure
4e). Additionally domains with homeotropic alignment can be
observed for 8 if a λ/4-plate is employed in front of the analyzer
for the slowly cooled sample (Figure 4f). This indicates an
ordering parallel to the substrate surface (homeotropic align-
ment) at low cooling velocities. Figure 4g shows the texture of
9 annealed in the mesophase at 108 °C displaying typical
dendritic aggregates of Colh phase and Figure 4h represents the
texture upon shearing the sample at the same film position,
illustrating the high viscosity of these systems.
It is highly interesting to compare PBIs 5 and 6, both bearing
an identical number of side chain atoms. The only difference
here lies in the flexibility of the respective substituents. For both
PBIs, R1 is -C7H15, but R2 differs in flexibility. In 5 an alkyl
swallow-tail substituent is used, in contrast to an OEG swallow-
tail substituent in 6. It can be observed that 5 melts from the
crystalline state into the isotropic phase at 99 °C and the
respective crystallization upon cooling is strongly supercooled
X-Ray Diffraction Experiments on Liquid Crystalline
PBIs. Additionally X-ray diffraction experiments were carried
out to clearly elucidate the order parameters and to confirm the
nature of the mesophases of the liquid crystalline PBIs 1, 3, 4,
6, 7, 8 and 9 unequivocally. This also helps to understand the
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14448 J. AM. CHEM. SOC. VOL. 131, NO. 40, 2009

Swallow-Tail Substituted Liquid Crystalline PBIs
A R T I C L E S
Figure 7. Schematic representation of discotic columnar hexagonal packing
parameters in liquid crystalline mesophases. Intercolumnar layer spacing
d100, hexagonal lattice parameter ahex and intracolumnar repeat distance c
(d001) for discotic molecules. More geometric considerations result in the
1
1
1
1
1
1
characteristic ratios of 1:
:
:
:
:
:
for the d spacings of the
√
3
√
4
√
7
√
9
√ √
12 13
(100), (110), (200), (210), (300), (220), and (310) reflections of a hexagonal
lattice in the small-angle regime.
Table 2. Hexagonal Lattice Parameters: Intercolumnar Layer
Spacing d100 [Å], Hexagonal Lattice Parameter ahex [Å] and
Intracolumnar Repeat Distance c [Å] for PBIs 1, 3, 4, 6, 7, 8 and 9
in the Liquid Crystalline Mesophase, as Determined from
Temperature Dependent X-Ray Diffraction Experiments
a
PBI
R1/R2
T [°C] phase d100 [Å] ahex [Å] c [Å]
1
3
4
6
R1 ) R2 ) C7H15
120 Colh 18.02 20.81 3.51
R1 ) R2 ) CH2(OCH2CH2)2OMe 100 Colh 18.02 20.81 3.48
Figure 5. DSC thermograms of unsymmetrical type III PBIs, 10 and 11,
showing the second heating and first cooling cycle at a heating rate of 10
K min-1 with respective transition temperatures (°C). Red curves show the
second heating cycle and blue curves represent the first cooling cycle.
R1 ) R2 ) CH2(OCH2CH2)3OMe 80 Colh 19.89 22.97 3.48
R1 ) C7H15
R2 ) CH2(OCH2CH2)2OMe
R1 ) C7H15
R2 ) CH2(OCH2CH2)3OMe
R1 ) C11H23
R2 ) CH2(OCH2CH2)2OMe
R1 ) C11H23
R2 ) CH2(OCH2CH2)3OMe
120 Colh 18.39 21.23 3.48
120 Colh 19.19 22.16 3.49
90 Colh 19.89 22.97 3.46
90 Colh 20.73 23.94 3.47
7
8
9
a Hexagonal lattice parameter ahex
)
ꢀ(4/3 d2100).
2
expected, 4 with the larger OEG-substituent also has the biggest
unit cell ahex ) 22.97 Å. Interestingly PBI 1 carrying only alkyl
substituents has the same hexagonal packing parameter ahex
)
20.81 Å as PBI 3 with a comparatively larger OEG N-
substituent. This fact also implies a higher conformational
freedom in the packing behavior of the OEG-substituents
compared to alkyl substituents.
Also for the unsymmetrically substituted type II PBIs 6, 7, 8
and 9, the diffractogramm (Figure 9) exhibits the typical liquid
Figure 6. Optical microscopic images of crystalline of type III PBIs (under
crossed polarizers). (a) Very long crystals of 11 formed upon annealing at
145 °C and (b) crystals of 10 formed upon annealing at 135 °C. The textures
were obtained upon cooling the sample from the isotropic phase and
annealing at the respective temperatures slightly above phase-transition
temperature.
crystalline columnar hexagonal Colh reflections d100 and d110
.
The differences in d100 are about 0.8 Å on changing the
oxyethylene repeating units from two to three in compounds 6
vs 7 as well as 8 vs 9. On the other hand, a change of about 1.5
Å in d100 spacing was observed for compounds 6 vs 8 as well
as 7 vs 9, in which the alkyl substituent length was varied from
R1 ) -C7H15 to -C11H23 respectively, maintaining the OEG
length the same. Also on comparison, compound 4 carrying only
OEG swallow-tail substituents exhibits a smaller d100 value of
19.89 Å than 9 with alkyl and OEG substituents with compa-
rable length (d100 ) 20.73 Å). This shows that the ether side
chains pack more tightly than alkyl substituents due to higher
conformational freedom of the C-O bond in OEG.
effect of the different substituents on hexagonal lattice param-
eters. Figure 7 presents the geometry and packing paramaters
for the columnar hexagonal liquid crystalline mesophase
(Colh).18 Packing parameters for PBIs under investigation as
determined from X-ray diffraction experiments are summarized
in Table 2.
Symmetrical type I PBIs 1, 3 and 4 show the d100 and d110
reflections displaying a columnar hexagonal mesophase with
the characteristic perylene-perylene stacking-distance of c )
3.4-3.5 Å (from d001 reflection at about 25.5°) in the columns
(Figure 8). Additionally, the sharp d001 reflexes at approximately
25.5° for all LC compounds are typical for a high order in the
intracolumnar packing of the discotic molecules. For 1, the d100
and d200 reflections can be observed. The diffuse halo at bigger
angles (>10°) arises from the liquid-like N-substituents. As
The unsymmetrical type III PBIs 10 and 11 with one linear side
chain and one swallowtail side chain show several crystalline
reflections in XRD, typical for polycrystalline materials.
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A R T I C L E S
Wicklein et al.
Figure 8. X-ray diffraction patterns of Colh perylene bisimides 1 (at 120
°C), 3 (at 100 °C) and 4 (at 80 °C) measured in the Colh mesophase.
Conclusion
Several symmetrically and unsymmetrically N-substituted
perylene bisimides have been successfully synthesized by two
different synthetic strategies. The substituents used involved
swallow-tail and linear alkyl- or oligooxyethylene (OEG)
substituents. The focus of investigation was directed toward
designing tailor-made liquid crystalline PBIs and to elucidate a
structure-property relationship with respect to thermotropic
behavior in N-substituted derivatives of PBIs. To this end, only
N-substitution was considered and bay substitution was avoided
to keep the optical and electronical properties similar. Ther-
motropic behavior was examined by DSC, POM and XRD
measurements in the mesophase temperature range. Several PBIs
exhibiting columnar hexagonal liquid crystalline Colh behavior
with broad LC temperature window were obtained by this
approach. It could be shown that OEG swallow-tail substituents
efficiently support Colh behavior and that both N-substituents
have to be branched in nature. A reduction to linear N-
substituents resulted in strongly crystalline behavior. By an
unsymmetrical substitution pattern, the melting point to the
liquid crystalline phase as well as clearing temperature could
be controlled very efficiently. Upon cooling the LC phase, the
crystallization process of these PBIs is strongly supercooled.
Thus, these novel liquid crystalline PBIs are highly promising
candidates to be applied in organic electronics like field-effect
transistors or photovoltaic devices. Our current investigations
toward devices deal with substrate/molecule interaction and
orientation of these molecules on alignment layers deposited
on device substrates. Preliminary results indicate uniaxial edge-
on to the surface orientation of molecules, which is ideal for
OFETs. The detailed device results will be published later.
Figure 9. X-ray diffraction patterns of perylene bisimides 6 (at 120 °C),
7 (at 120 °C), 8 (at 90 °C) and 9 (at 90 °C) measured in the Colh mesophase.
(Inset) d100 intercolumnar reflections with respective repeat distances.
ylenglycol monomethyl ether, tetraethyleneglycol monomethyl ether
and solvents, were purchased from Merck, Aldrich, Fluka or TCI
and used without any further purification. Solvents used for
precipitation and column chromatography were distilled under
normal atmosphere. For the synthesis of perylene intermediates
12a,b35,54 and 14a-c,36 see Supporting Information. All swallow-
tail and linear bromides43,49 or amines41,42,44-48 respectively were
synthesized according to published procedures.
1H- and 13C NMR spectra were recorded on a Bruker AC 250
spectrometer (250 MHz). Chemical shifts are reported in ppm at
room temperature using CDCl3 as solvent and tetramethylsilane as
internal standard unless indicated otherwise. Abbreviations used
for splitting patterns are s ) singlet, d ) dublett, t ) triplet, qui )
quintet, m ) multiplet. Gel permeation chromatography (GPC) was
performed on a Waters size exclusion chromatography system for
oligomers (analytical columns: cross-linked polystyrene gel, length
2 × 60 cm, width 0.8 cm, particle size 5 µm, pore size 100 Å,
eluent THF (0.5 mL min-1, 80 bar), and polystyrene calibration).
IR spectroscopy was carried out with a BioRad Digilab FTS-40
(FT-IR) in the range of 400-4000 cm-1. Mass spectroscopic data
were obtained from a FINNIGAN MAT 8500 instrument. Mi-
croanalyses were carried out with a PERKIN-ELMER 2400 CHN
elemental analyzer. The thermal degradation of PBI derivatives was
studied using a Mettler Toledo TGA/SDTA 851e with a heating
rate of 10 K min-1 under N2 atmosphere. Differential scanning
calorimetry (DSC) was carried out with a Perkin-Elmer Diamond
DSC with a heating rate of 10 K min-1 unless otherwise indicated
under N2-atmosphere. The instrument was calibrated with indium
Experimental Section
Materials and Methods. The starting materials, perylenetetra-
carboxylic acid dianhydride PTCDA, pentadecane-8-one, tricosan-
12-one, 1-bromononane, diethylenglycol monomethyl ether, trieth-
(54) Wescott, L. D.; Mattern, D. L. J. Org. Chem. 2003, 68, 10058–10066.
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Swallow-Tail Substituted Liquid Crystalline PBIs
A R T I C L E S
standards before measurements. Phase transitions were also exam-
ined by a polarization optical microscop (POM) Nikon Diaphot
300 with a Mettler FP 90 temperature-controlled hot stage. X-ray
diffraction measurements were performed on a Huber Guinier
Diffraktometer 6000 equipped with a Huber quartz monochromator
611 with Cu-KR1: 1.54051 Å. For cyclic voltammetry (CV)
experiments, a conventional three-electrode assembly using a Ag/
AgNO3 reference electrode was used. CH2Cl2 containing 0.1 M
Bu4NPF6 was used as solvent. All measurements were carried out
under N2-atmosphere at a scan rate of 0.05 V s-1 at 25 °C and all
redox potentials were calibrated to ferrocene/ferrocenium couple
(Fc/Fc+).
General Procedure for the Preparation of Symmetrical
N,N′-Di(1-alkyl swallow-tail)-perylene-3,4,9,10-tetracarboxylic
Bisimides 1 and 2.35,54 A mixture of perylene-3,4,9,10-tetracar-
boxylic dianhydride PTCDA (1.0 mmol), Zn(OAc)2 (0.75 mmol),
imidazole (4.0 g) and the respective alkyl swallow-tail amine (3.0
mmol) was vigorously stirred at 160 °C for 2 h. After cooling to
r.t., the mixture was dissolved in minimum amount of THF and
precipitated in 300 mL 2N HCl/MeOH 2:1 V/V. The precipitate was
collected by filtration, washed with H2O followed by MeOH and
dried at 80 °C in vacuum. The crude product was further purified
by column chromatography.
N,N′-Di(1-octylheptyl)-perylene-3,4,9,10-tetracarboxylic Bi-
simide 1. Perylene-3,4,9,10-tetracarboxylic dianhydride (1.96 g, 5.0
mmol) and 8-octylheptylamine (3.41 g, 15.0 mmol) were allowed
to react according to the above general procedure. The crude product
was further purified by silica flash-column chromatography with
n-hexane/CHCl3 2:1 V/V. The final product was freeze-dried from
benzene and was obtained as a red solid (2.68 g, 66.1%). Mp 135.5
°C. Calcd for C54H70N2O4: C 79.96, H 8.70, N 3.45. Found: C 79.84,
H 8.59, N 3.32. EI-MS (70 eV): m/z 811.0 [M+, 70.78%]. IR (ATR):
ν ) 2952 m, 2922 m, 2853 m, 1697 s, 1654 s, 1593 s, 1578 m,
1505 w, 1460 m, 1433 m, 1404 m, 1335 s, 1251 m, 1207 m,
1172 m, 1123 w, 1108 w, 962 w, 850 w, 809 m, 795 w, 745 m,
723 cm-1 m. 1H NMR (250 MHz, CDCl3, 298K): δ ) 0.82 (t, J )
6.8 Hz, 12H, 4CH3), 1.12-1.41 (m, 40H, 20CH2), 1.77-1.96 (m,
4H, 2RCH2), 2.15-2.36 (m, 4H, 2RCH2), 5.10-5.27 (m, 2H,
N-CH), 8.52-8.76 (m, 8H, 8ArH) ppm. 13C NMR (62.5 MHz,
CDCl3, 298K): δ ) 14.40 (4C, CH3), 22.95, 27.32, 29.56, 29.85,
32.14, 32.71 (24C, CH2), 55.11 (2C, N-CH), 123.35, 123.54,
124.28, 131.46, 132.23, 126.77, 129.93, 134.83 (20C, CAr), 163.90,
164.99 (4C, CONR) ppm.
amine (27.0 mmol) was stirred at 140 °C for 48 h. The resulting
burgundy colored mixture was cooled, diluted with methylene
chloride, and filtered through Celite to remove excess dianhydride.
The filtrate was dried over MgSO4 and concentrated under reduced
pressure. The crude product was further purified by flash column
chromatography.
N,N′-Di(2-(1,3-bis(2-(2-(2-methoxyl)ethoxyl)ethoxyl)propyl))-
perylene-3,4,9,10-tetracarboxylic Bisimide 3. Perylene-3,4,9,10-
tetracarboxylic dianhydride (5.12 g, 13.03 mmol) and 1,3-bis(2-
(2-methoxyethoxy)ethoxy) propane-2-amine (10.34 g, 35.2 mmol)
were allowed to react according to the general procedure. The crude
product was further purified by silica flash-column chromatography
with CHCl3 and then CHCl3/MeOH 98:2 V/V. The final product
was freeze-dried from benzene and was obtained as a red solid
(10.7 g, 81.6%). Mp 145.8 °C. Calcd for C50H62N2O16: C 63.41, H
6.60, N 2.96. Found C 63.19, H 6.63, N 2.85. EI-MS (70 eV): m/z
946.7 [M+, 10.70%]. IR (ATR): ν ) 2984 w, 2920 m, 2870 m,
2825 w, 1695 s, 1653 s, 1593 s, 1575 m, 1508 w, 1459 w, 1435 w,
1359 m, 1341 s, 1305 w, 1284 w, 1253 m, 1196 w, 1182 w, 1092 s,
1052 m, 1026 m, 962 m, 947 m, 850 m, 810 s, 796 m, 745 s,
1
711 w cm-1. H NMR (250 MHz, CDCl3, 298K): δ ) 3.27 (s,
12H, 4OCH3-OEG), 3.38-3.45 (m, 8H, 4OCH2-OEG), 3.52-3.78
(m, 24H, 12OCH2-OEG) 3.98 (dd, J ) 10.6 Hz, J ) 5.9 Hz, 4H,
2ROCH2-OEG), 4.19 (dd, J ) 10.6 Hz, J ) 7.8 Hz, 4H, 2ROCH2-
OPEG), 5.63-5.79 (m, 2H, 2N-CH-OEG), 8.46-8.72 (m, 8H,
8ArH in perylene ring) ppm. 13C NMR (62.5 MHz, CDCl3, 298K):
δ ) 52.51 (2C, N-CH), 59.28 (4C, OCH3), 69.66, 70.70, 70.80,
70.85, 72.17 (10C, OCH2), 123.20, 123.63, 126.31, 129.57, 131.64,
134.50 (20C, CAr), 164.03 (4C, CONR) ppm.
N,N′-Di(2-(1,3-bis(2-(2-(2-(2-methoxyl)ethoxyl)ethoxyl)ethoxyl)-
propyl))-perylene-3,4,9,10-tetracarboxylic Bisimide 4. Perylene-
3,4,9,10-tetracarboxylic dianhydride (785 mg, 2.0 mmol) and 1,3-
bis(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)propane-2-amine (2.07 g,
5.4 mmol) were allowed to react according to the general procedure.
The crude product was further purified by silica flash-column
chromatography with CHCl3 and then CHCl3/MeOH 98:2 V/V. The
final product was freeze-dried from benzene and was obtained as
a red solid (1.79 g, 79.6%). Mp 126.9 °C. Calcd for C58H78N2O20:
C 62.02, H 7.00, N 2.49. Found: C 61.58, H 6.69, N 2.28. IR (ATR):
ν ) 2976 w, 2912 w, 2868 m, 2821 w, 1694 s, 1653 s, 1593 m,
1575 m, 1448 w, 1435 w, 1404 m, 1355 m, 1343 s, 1307 w, 1250 m,
1197 w, 1181 w, 1135 m, 1098 s, 1052 m, 1026 m, 967, m, 875 w,
1
858 m, 809 s, 797 w, 745 s, 711 w cm-1. H NMR (250 MHz,
CDCl3, 298K): δ (ppm) ) 3.32 (s, 12H, 4OCH3-OEG), 3.42-3.78
(m, 48H, 12OCH2-PEG), 3.97 (dd, J ) 10.6 Hz, J ) 5.8 Hz, 4H,
2ROCH2-OEG), 4.20 (dd, J ) 10.6 Hz, J ) 7.8 Hz, 4H, 2ROCH2-
OEG), 5.64-5.76 (m, 2H, 2N-CH-OEG), 8.41-8.60 (m, 8H,
8ArH). 13C NMR (62.5 MHz, CDCl3, 298K): δ ) 52.46 (2C,
N-CH), 59.32 (4C, OCH3), 69.66, 70.67, 70.79, 70.82, 70.87, 72.21
(28C, OCH2), 123.35, 123.74, 126.56, 129.77, 131.79, 134.74 (20C,
CAr), 164.13 (4C, CONR).
General Procedure for the Preparation of Unsymmetrical
N-(1-Alkyl swallow-tail)-N′-(1-OEG swallow-tail)-perylene-
3,4,9,10-tetracarboxylic Bisimides 6, 7, 8, and 9 via Condensa-
tion Reaction. A mixture of the respective N-(1-alkyl swallow-
tail)-perylene-3,4,9,10-tetracarboxylic-3,4-anhydride-9,10-imide (1.0
mmol), Zn(OAc)2 (1.5 mmol) in dry DMAc (6.0 mL) and the
respective amine (1.8 mmol) was stirred in a microwave pressure
reactor for 20 min at 160 °C and 200 W. After cooling to r.t. the
mixture was dissolved in minimum amount of THF and precipitated
in 300 mL 2N HCl/MeOH 2:1 V/V. After standing overnight, the
precipitate was collected by filtration, washed with H2O, then
MeOH and dried at 60 °C in vacuum. The crude product was further
purified by column chromatography on silica flash-gel (see respec-
tive compound for details).
N,N′-Di(1-dodecylundecyl)-perylene-3,4,9,10-tetracarboxyl-
ic Bisimide 2. Perylene-3,4,9,10-tetracarboxylic dianhydride (3.92
g, 10 mmol) and 12-dodecylundecylamine (10.19 g, 30.0 mmol)
were allowed to react according to the general procedure. The crude
product was further purified by silica flash-column chromatography
with CHCl3. The final product was freeze-dried from benzene and
was obtained as an orange solid (9.76 g, 94.3%). Mp 76.8 °C. Calcd
for C70H102N2O4: C 81.19, H 9.93, N 2.71. Found C 80.93, H 9.56,
N 2.47. EI-MS (70 eV): m/z 1033.8 [M+, 76.14%]. IR (ATR): ν )
2952 m, 2919 s, 2849 s, 1694 s, 1650 s, 1592 s, 1577 m, 1507 w,
1466 m, 1434 w, 1405 m, 1335 s, 1273 w, 1252 s, 1211 w, 1194 w,
1175 w, 1156 w, 1125 w, 1100 w, 959 w, 866 w, 856 w, 844 w,
1
813 s, 796 w, 773 w, 750 s, 721 m cm-1. H NMR (250 MHz,
CDCl3, 298K): δ ) 0.83 (t, J ) 6.8 Hz, 12H, 4CH3), 1.01-1.44
(m, 72H, 36CH2), 1.76-1.96 (m, 4H, 2RCH2), 2.15-2.34 (m, 4H,
2RCH2), 5.09-5.26 (m, 2H, N-CH), 8.52-8.76 (m, 8H, 8ArH)
ppm. 13C NMR (62.5 MHz, CDCl3, 298K): δ ) 14.43 (4C, CH3),
23.00, 27.30, 29.66, 29.88, 29.92, 29.94, 29.95, 32.24, 32.70 (36C,
CH2), 55.11 (2C, N-CH), 123.32, 131.45, 132.21, 123.54, 124.30,
126.76, 129.92, 134.80 (20C, CAr), 163.90, 164.97 (4C, CONR)
ppm.
General Procedure for the Preparation of Symmetrical
N,N′-Di(1-OEG swallow-tail)-perylene-3,4,9,10-tetracarboxy-
lic Bisimides 3 and 4:24 A mixture of perylene-3,4,9,10-tetracar-
boxylic dianhydride PTCDA (10.0 mmol), Zn(OAc)2 (7.5 mmol)
in dry pyridine (75.0 mL) and the respective OEG swallow-tail
N-(1-octylheptyl)-N′-(2-(1,3-bis(2-(2-(2-methoxyl)ethoxyl)ethoxyl)-
propyl))-perylene-3,4,9,10-tetracarboxylic Bisimide 6. N-(1-octyl-
heptyl)-perylene-3,4,9,10-tetracarboxylic-3,4-anhydride-9,10-imi-
de 12a (602 mg, 1 mmol) and 1,3-bis(2-(2-methoxyethoxy)ethoxy)
9
J. AM. CHEM. SOC. VOL. 131, NO. 40, 2009 14451

A R T I C L E S
Wicklein et al.
propane-2-amine (532 mg, 1.8 mmol) were allowed to react
according to the general procedure. The crude product was further
purified by silica flash-column chromatography with CHCl3/AcOH
10:1 V/V to elute impurities and then CHCl3/MeOH 95:5 V/V to elute
6. The final product was freeze-dried from benzene and was
obtained as a red solid (840 mg, 95.6%). Mp 154.4 °C. Calcd for
C52H66N2O10: C 71.05, H 7.57, N 3.19. Found C 70.83, H 7.03, N
3.13. EI-MS (70 eV): m/z 878.7 [M+, 22.89%]. IR (ATR): ν )
2952 w, 2923 m, 2854 m, 1694 s, 1653 s, 1593 m, 1576 m, 1455 m,
1434 m, 1404 m, 1335 s, 1249 m, 1197 w, 1178 w, 1123 m,
1102 m, 1078 m, 1042 m, 1018 m, 963 w, 850 m, 808 s, 797 m,
745 s, 724 w cm-1. 1H NMR (250 MHz, CDCl3, 298K): δ ) 0.82
(t, J ) 6.8 Hz, 6H, 2CH3), 1.10-1.45 (m, 20H, 10CH2), 1.78-1.96
(m, 2H, RCH2), 2.15-2.35 (m, 2H, RCH2), 3.27 (s, 6H,
2OCH3-PEG), 3.38-3.45 (m, 4H, 2OCH2-PEG), 3.51-3.80 (m,
12H, 6OCH2-PEG), 3.97 (dd, J ) 10.5 Hz, J ) 5.8 Hz, 2H,
ROCH2-OEG), 4.19 (dd, J ) 10.5 Hz, J ) 7.8 Hz, 2H,
ROCH2-OEG), 5.10-5.27 (m, 1H, N-CH), 5.63-5.79 (m, 1H,
N-CH-OEG), 8.44-8.75 (m, 8H, 8ArH) ppm. 13C NMR (62.5
MHz, CDCl3, 298K): δ ) 14.39 (2C, CH3), 22.94, 27.34, 29.56,
29.85, 32.13, 32.70 (12C, CH2), 52.50 (1C, N-CH-OEG), 55.11
(1C, N-CH), 59.29 (2C, OCH3-OEG), 69.64, 70.71, 70.81, 70.86,
72.18 (10C, OCH2-OEG), 123.12, 123.31, 123.63, 124.26, 126.48,
126.55, 129.73, 129.76, 131.39, 131.63, 132.16, 134.53, 134.70
(20C, CAr), 163.76 (C, CONR), 164.06 (2C, CONR-OEG), 164.86
(C, CONR) ppm.
N-(1-Octylheptyl)-N′-(2-(1,3-bis(2-(2-(2-(2-methoxyl)ethoxyl)-
ethoxyl)ethoxyl)propyl))-perylene-3,4,9,10-tetracarboxylic Bi-
simide 7. N-(1-octylhepty)-perylene-3,4,9,10-tetracarboxylic-3,4-
anhydride-9,10-imide (1.2 g, 2.0 mmol) and 1,3-bis(2-(2-(2-
methoxyethoxy)ethoxy)ethoxy) propane-2-amine 19d (1.38 g, 3.6
mmol) were allowed to react according to the general procedure.
The crude product was further purified by silica flash-column
chromatography with CHCl3/AcOH 99:1 to 9:1 V/V to elute
impurities and then CHCl3/MeOH 95:5 V/V to elute 7. The final
product was freeze-dried from benzene and was obtained as a red
solid (1.52 g, 78.6%). Mp 148.7 °C. Calcd for C56H74N2O12: C
69.54, H 7.71, N 2.90. Found C 69.33, H 7.81, N 2.77. EI-MS (70
eV): m/z 966.4 [M+, 20.18%]. IR (ATR): ν ) 2956 w, 2923 m,
2855 m, 2813 w, 1694 s, 1653 s, 1593 s, 1576 m, 1506 w, 1455 w,
1435 w, 1404 m, 1337 s, 1302 m, 1250 m, 1197 w, 1178 w, 1139 m,
1102 s, 1078 m, 1034 m, 964 w, 851 m, 809 s, 797 w, 746 s,
724 w cm-1. 1H NMR (250 MHz, CDCl3, 298K): δ ) 0.81 (t, J )
6.8 Hz, 6H, 2CH3), 1.07-1.46 (m, 20H, 10CH2), 1.77-1.95 (m,
2H, RCH2), 2.16-2.34 (m, 2H, RCH2), 3.31 (s, 6H, 2OCH3-OEG),
3.44-3.77 (m, 24H, 12OCH2-OEG), 3.96 (dd, J ) 10.6 Hz, J )
5.8 Hz, 2H, ROCH2-OEG), 4.20 (dd, J ) 10.6 Hz, J ) 7.8 Hz,
2H, ROCH2-OEG), 5.12-5.25 (m, 1H, N-CH), 5.64-5.76 (m,
1H, N-CH-OEG), 8.39-8.72 (m, 8H, 8ArH) ppm. 13C NMR (62.5
MHz, CDCl3, 298K): δ ) 14.41 (2C, CH3), 22.94, 27.31, 29.56,
29.85, 32.12, 32.67 (12C, CH2), 52.35 (1C, N-CH-OEG), 55.09
(1C, N-CH), 59.33 (2C, OCH3-OEG), 69.60, 70.64, 70.78, 70.80,
70.84, 72.18 (14C, OCH2-OEG), 123.20, 123.37, 123.62, 124.24,
126.53, 126.59, 129.77, 131.42, 132.20, 134.59, 134.78 (20C, CAr),
163.83 (C, CONR), 164.09 (2C, CONR-OEG), 164.92 (C, CONR)
ppm.
1576 m, 1456 w, 1434 w, 1404 m, 1338 s, 1250 m, 1197 w, 1176 w,
1107 s, 1082 m, 1018 m, 963 w, 849 m, 809 s, 795 w, 745 s,
720 w cm-1. 1H NMR (250 MHz, CDCl3, 298K): δ ) 0.83 (t, J )
6.8 Hz, 6H, 2CH3), 1.07-1.42 (m, 36H, 18CH2), 1.80-1.95 (m,
2H, RCH2), 2.18-2.33 (m, 2H, RCH2), 3.27 (s, 6H, 2OCH3-OEG),
3.39-3.44 (m, 4H, 2OCH2-OEG), 3.52-3.78 (m, 12H,
6OCH2-OEG), 3.97 (dd, J ) 10.6 Hz, J ) 5.8 Hz, 2H,
ROCH2-OEG), 4.20 (dd, J ) 10.6 Hz, J ) 7.8 Hz, 2H,
ROCH2-OEG), 5.12-5.25 (m, 1H, N-CH), 5.65-5.77 (m, 1H,
N-CH-OEG), 8.42-8.70 (m, 8H, 8ArH) ppm. 13C NMR (62.5
MHz, CDCl3, 298K): δ ) 14.41 (2C, CH3), 22.97, 27.33, 29.64,
29.89, 29.91, 29.94, 32.21, 32.69 (20C, CH2), 52.50 (1C, N-CH-
OEG), 55.11 (1C, N-CH), 59.28 (2C, OCH3-OEG), 69.65, 70.71,
70.80, 70.85, 72.18 (10C, OCH2-OEG), 123.08, 123.29, 123.59,
124.25, 126.42, 126.50, 129.68, 129.72, 131.36, 131.60, 132.14,
134.48, 134.65 (20C, CAr), 163.77 (C, CONR), 164.04 (2C, CONR-
OEG), 164.86 (C, CONR) ppm.
N-(1-Dodecylundecyl)-N′-(2-(1,3-bis(2-(2-(2-(2-methoxyl)ethoxyl)-
ethoxyl)ethoxyl)propyl))-perylene-3,4,9,10-tetracarboxylic Bisim-
ide 9. N-(1-dodecylundecyl)-perylene-3,4,9,10-tetracarboxylic-3,4-
anhydride-9,10-imide 12b (1.0 g, 1.4 mmol) and 1,3-bis(2-(2-(2-
methoxyethoxy)ethoxy)ethoxy) propane-2-amine (970 mg, 2.5
mmol) were allowed to react according to the general procedure.
The crude product was further purified by silica flash-column
chromatography with CHCl3/AcOH 99:1 to 9:1 V/V to elute
impurities and then with CHCl3/MeOH 95:5 V/V to elute 9. The
final product was freeze-dried from benzene and was obtained as
a red solid (652 mg, 43.1%). Mp 111.2 °C. Calcd for C64H90N2O12:
C 71.21, H 8.40, N 2.60. Found: C 70.87, H 8.67, N 2.41. EI-MS
(70 eV): m/z 1080.3 [M+, 34.38%]. IR (ATR): ν ) 2952 w, 2921 m,
2852 m, 2813 w, 1694 s, 1654 s, 1593 s, 1576 m, 1507 w, 1456 m,
1435 m, 1404 m, 1337 s, 1251 m. 1197 w, 1180 w, 1139 m, 1104 s,
1078 m, 1030m, 963 w, 849 m, 809 s, 797 w, 746 s, 722 w cm-1
.
1H NMR (250 MHz, CDCl3, 298K): δ ) 0.82 (t, J ) 6.8 Hz, 6H,
2CH3), 1.06-1.43 (m, 36H, 18CH2), 1.78-1.94 (m, 2H, RCH2),
2.16-2.34 (m, 2H, RCH2), 3.31 (s, 6H, 2OCH3-OEG), 3.40-3.78
(m, 24H, 12OCH2-OEG), 3.96 (dd, J ) 10.6 Hz, J ) 5.8 Hz, 2H,
ROCH2-OEG), 4.20 (dd, J ) 10.6 Hz, J ) 7.8 Hz, 2H,
ROCH2-OEG), 5.12-5.25 (m, 1H, N-CH), 5.64-5.76 (m, 1H,
N-CH-OEG), 8.36-8.78 (m, 8H, 8ArH) ppm. 13C NMR (62.5
MHz, CDCl3, 298K): δ ) 14.44 (2C, CH3), 22.99, 27.30, 29.65,
29.88, 29.92, 29.94, 32.21, 32.66 (20C, CH2), 52.35 (1C, N-CH-
OEG), 55.08 (1C, N-CH), 59.33 (2C, OCH3-OEG), 69.60, 70.64,
70.78, 70.80, 70.84, 72.18 (14C, OCH2-OEG), 123.20, 123.36,
123.58, 124.24, 126.53, 126.59, 129.77, 131.44, 132.18, 134.59,
134.79 (20C, CAr), 163.84 (C, CONR), 164.11 (2C, CONR-OEG),
164.91 (C, CONR) ppm.
General Procedure for the Preparation of unsymmetrical
Perylene-3,4,9,10-tetracarboxylic Bisimides 5, 10, and 11 via
Nucleophilic Substitution. Method A. A mixture of the respective
N-(1-swallow-tail)-perylene-3,4,9,10-tetracarboxylic-3,4-anhydride-
9,10-imide (1.0 mmol), K2CO3 (1.8 mmol), KI (0.2 mmol) and the
respective bromide (1.8 mmol) in 20 mL absolute DMF was stirred
at 80 °C for 3-7 d. The conversion was monitored via TLC or
GPC. Purification procedures are described for each compound
separately.
Method B. To a suspension of the respective N-(1-swallow-tail)-
perylene-3,4,9,10-tetracarboxylic-3,4-anhydride-9,10-imide (1.0 mmol)
in dry DMF (30 mL) was added NaH (1.2 mmol), as 60%
suspension in mineral oil, at 0 °C. The mixture was stirred and
allowed to reach RT, then the respective bromide (2.5 mmol) was
added and heated to 80 °C. After 48 h, the reaction was cooled to
room temperature and quenched by addition of saturated NH4Cl
solution (2.5 mL). Purification procedures are described in the
corresponding compound section.
N-(1-Decylnonyl)-N′-(1-octylheptyl)-perylene-3,4,9,10-tetra-
carboxylic Bisimide 5. N-(1-octylheptyl)-perylene-3,4,9,10-tetra-
carboxylic bisimide 14a (901 mg, 1.5 mmol) and 10-bromonona-
decane (938 mg, 2.7 mmol) were allowed to react according to the
N-(1-Dodecylundecyl)-N′-(2-(1,3-bis(2-(2-(2-methoxyl)ethoxyl)-
ethoxyl)propyl))-perylene-3,4,9,10-tetracarboxylic Bisimide 8. N-(1-
dodecylundecyl)-perylene-3,4,9,10-tetracarboxylic-3,4-anhydride-
9,10-imide 12b (714 mg, 1 mmol) and 1,3-bis(2-(2-methoxyethox-
y)ethoxy) propane-2-amine (532 mg, 1.8 mmol) were allowed to
react according to the general procedure. The crude product was
further purified by silica flash-column chromatography with CHCl3/
AcOH 10:1 V/V to elute impurities and then CHCl3/MeOH 95:5
V/V to elute 8. The final product was freeze-dried from benzene
and was obtained as a red solid (620 mg, 62.1%). Mp 107.7 °C.
Calcd for C60H82N2O10: C 72.70, H 8.34, N 2.83. Found C 72.37,
H 8.34, N 2.83. EI-MS (70 eV): m/z 990.1 [M+, 25.66%]. IR (ATR):
ν ) 2952 w, 2921 m, 2852 m, 2817 w, 1694 s, 1653 s, 1593 s,
9
14452 J. AM. CHEM. SOC. VOL. 131, NO. 40, 2009

Swallow-Tail Substituted Liquid Crystalline PBIs
A R T I C L E S
general procedure Method A for 7 d. After cooling to r.t., the
product was precipitated in 300 mL 2N HCl/MeOH 2:1 V/V. After
standing overnight, the precipitate was collected by filtration,
washed with H2O, then MeOH and dried at 60 °C in vacuum. The
crude product was further purified by column chromatography on
silica flash-gel (petrolether/CHCl3 1:1 to 1:4 V/V). The final product
was freeze-dried from benzene and was obtained as a red solid
(762 mg, 58.6%). Mp 98.8 °C. Calcd for C58H78N2O4: C 80.33, H
9.07 N 3.23. Found C 79.98, H 10.27, N 3.34. EI-MS (70 eV): m/z
866.6 ([M+], 81.27%). IR (ATR): ν ) 2956 w, 2922 m, 2853 m,
1695 s, 1651 s, 1593 s, 1578 m, 1460 w, 1434 w, 1405 m, 1335 s,
1251 m, 1209 w, 1172 m, 1124 w, 1108 w, 850 w, 809 m, 795 m,
746 m, 722 w cm-1. 1H NMR (250 MHz, CDCl3, 298K): δ ) 0.82
(t, J ) 6.2 Hz, 12H, 4CH3), 1.10-1.42 (m, 48H, 24CH2), 1.76-1.95
(m, 4H, 2RCH2), 2.14-2.35 (m, 4H, 2RCH2), 5.10-5.26 (m, 2H,
N-CH), 8.53-8.76 (m, 8H, 8ArH) ppm. 13C NMR (62.5 MHz,
CDCl3, 298K): δ ) 14.45, 14.48 (4C, CH3), 23.00, 23.03, 27.36,
29.61, 29.65, 29.93, 32.18, 32.24, 32.74 (28C, CH2), 55.14 (2C,
N-CH), 123.36, 123.57, 124.28, 131.47, 132.21, 126.78, 129.95,
134.83 (20C, CAr), 163.95, 165.03 (4C, CONR) ppm.
4HAr) ppm. 13C NMR (62.5 MHz, CDCl3, 298K): δ ) 14.45 (1C,
CH3), 23.02, 27.52, 28.46, 29.68, 29.73, 29.92, 29.97, 29.99 (9C,
CH2), 32.25 (1C, ꢀ-CH2), 41.05 (1C, N-CH2), 52.48 (1C, N-CH-
OEG), 59.32 (2C, OCH3-OEG), 69.66, 70.68, 70.83, 70.87, 72.21
(14C, OCH2-OEG), 123.16, 123.22, 123.48, 123.70, 126.03,
126.45, 129.39, 129.63, 131.49, 134.51, 134.57 (20C, CAr), 163.50,
164.00 (4C, CONR) ppm.
N-(1-Dodecylundecyl)-N′-(1-(2-(2-(2-(2-methoxy)ethoxy)ethoxy)-
ethoxy)ethyl)-perylene-3,4,9,10-tetracarboxylic Bisimide 11. N-(1-
dodecylundecyl)-perylene-3,4,9,10-tetracarboxylic bisimide 14b
(901 mg, 1.5 mmol) and 1-Bromo-tetraethyleneglycol monomethyl
ether (881 mg, 3.25 mmol) were allowed to react according to the
general procedure Method B for 48 h. After cooling to r.t., the
product was precipitated in 300 mL 2N HCl/MeOH 3:1 V/V. After
standing overnight, the precipitate was collected by filtration,
washed with H2O, then MeOH and dried at 60 °C in vacuum. The
crude product was further purified by column chromatography on
silica flash-gel (THF/hexane 1:1 V/V). The final product was freeze-
dried from benzene and was obtained as a red solid (631 mg,
53.7%). Mp 151.8 °C. Calcd for C56H74N2O8: C 74.47, H 8.26, N
3.10. Found: C 74.10, H 8.90, N 3.13. EI-MS (70 eV): m/z 902.3
([M+], 87.5%). IR (ATR): ν ) 2956 w, 2921 m, 2852 m, 1693 s,
1645 s, 1594 s, 1577 m, 1506 w, 1437 m, 1403 m, 1343 s, 1249 m,
1197 w, 1178 m, 1107 m, 1060 m, 1060 m, 1040 w, 857 m, 809 s,
794 m, 745 s, 720 w cm-1. 1H NMR (250 MHz, CDCl3, 298K): δ
) 0.84 (t, J ) 6.7 Hz, 6H, 2CH3), 1.07-1.43 (m, 36H, 18CH2),
1.78-1.97 (m, 2H, RCH2), 2.15-2.35 (m, 2H, RCH2), 3.34 (s, 3H,
OCH3), 3.47-3.54 (m, 2H, OCH2), 3.54-3.67 (m, 8H, OCH2),
3.69-3.76 (m, 2H, OCH2), 3.86 (t, J ) 5.9 Hz, 2H, OCH2), 4.47
(t, J ) 5.9 Hz, 2H, N-CH2), 5.10-5.26 (m, 1H, N-CH),
8.52-8.74 (m, 8H, 8ArH) ppm. 13C NMR (62.5 MHz, CDCl3,
298K): δ ) 14.48 (2C, CH3), 23.04, 27.41, 29.71, 29.96, 30.00,
32.28, 32.74 (20C, CH2), 39.61 (1C, N-CH2), 55.22 (1C, N-CH),
59.39 (1C, OCH3), 68.25, 70.44, 70.86, 70.94, 71.03, 72.28 (7C,
OCH2), 123.07, 123.24, 131.41, 126.36, 129.44, 129.69, 134.31,
134.63 (20C, CAr), 163.47 (4C, CONR) ppm.
N-(2-(1,3-Bis(2-(2-(2-(2-methoxyl)ethoxyl)ethoxyl)ethoxyl)propyl))-
N′-(1-dodecyl)-perylene-3,4,9,10-tetracarboxylic Bisimide 10. N-(2-
(1,3-bis(2-(2-(2-(2-methoxyl)ethoxyl)ethoxyl)ethoxyl)propyl))-
perylene-3,4,9,10-tetracarboxylic bisimide 14c (946 mg, 1.25 mmol)
and 12-bromododecane (561 mg, 2.25 mmol) were allowed to react
according to the general procedure Method A for 3 d. After cooling
to r.t. the mixture was poured into saturated NaCl solution and was
extracted with CHCl3. After drying over MgSO4 and removal of
solvent in vacuo, the crude product was further purified by column
chromatography on silica flash-gel (CHCl3/MeOH 98:2 V/V). The
final product was freeze-dried from benzene to afford 10 as a dark-
red solid (547 mg, 47.3%). Mp 140.1 °C. Calcd for C53H68N2O12:
C 68.81, H 7.41, N 3.01. Found: C 68.99, H 7.35, N 3.03. EI-MS
(70 eV): m/z 924.0 ([M+], 32.38%). IR (ATR): ν ) 2960 w,
2922 m, 2854 m, 2821 w, 1693 s, 1651 s, 1593s 1577 m, 1507 w,
1460 w, 1438 m, 1403 m, 1355m, 1343 s, 1249 m, 1198 w, 1180 w,
1
1104 s, 1030 m, 857 m, 809 s, 794 w, 745 s, 722 w cm-1. H
NMR (250 MHz, CDCl3, 298K): δ ) 0.87 (s, 3H, CH3), 1.12-1.53
(m, 18H, 9CH2), 1.67-1.84 (m, 2H, ꢀ-CH2), 3.31 (s, 6H, 2OCH3),
3.44-3.78 (m, 24H, 12OCH2), 3.94-4.02 (dd, J ) 10.5 Hz, J )
5.8 Hz, 2H, OEG-R-OCH2), 4.14-4.25 (m, 4H, OEG-R-OCH2,
N-CH2), 5.64-5.75 (m, 1H, N-CH-OEG), 8.41 (dd, J ) 8.2 Hz,
J ) 4.4 Hz, 4H, 4HAr), 8.54 (dd, J ) 14.4 Hz, J ) 8.0 Hz, 4H,
Supporting Information Available: Synthesis and character-
ization of perylene-intermediates. This material is available free
of charge via the Internet at http://pubs.acs.org.
JA905260C
9
J. AM. CHEM. SOC. VOL. 131, NO. 40, 2009 14453