Ion-pair-based assemblies comprising pyrrole-pyrazole hybrids

Article abstract of DOI:10.1002/chem.201300993

Modified 3,5-dipyrrolylpyrazole (DPP) derivatives in their protonated form produce planar [2+2]-type complexes with trifluoroacetate (TFA) ions. These complexes serve as constituent components of ion-pair-based assemblies. An essential strategy for the co

Full text of DOI:10.1002/chem.201300993

FULL PAPER
DOI: 10.1002/chem.201300993
Ion-Pair-Based Assemblies Comprising Pyrrole–Pyrazole Hybrids
Hiromitsu Maeda,*[a] Kengo Chigusa,[a] Tsuneaki Sakurai,[b] Kazuchika Ohta,[c]
Shinobu Uemura,[d] and Shu Seki[b]
Abstract: Modified 3,5-dipyrrolylpyrazole (DPP) derivatives in their protonated
form produce planar [2+2]-type complexes with trifluoroacetate (TFA) ions.
These complexes serve as constituent components of ion-pair-based assemblies.
An essential strategy for the construction of dimension-controlled organized struc-
tures based on these [2+2]-type complexes is the introduction of aryl rings bearing
long alkyl chains, which enables the formation of 2D patterns at interfaces, supra-
molecular gels, and mesophases.
Keywords: assembled structures
·
ion pairs · pi-conjugated molecules ·
pyrrole derivatives · soft materials ·
supramolecular chemistry
Introduction
Assemblies of p-conjugated molecules have attracted much
attention for the fabrication of functional materials.[1]
Among various protocols for assembling molecules, arrange-
ment of appropriately designed charged p-conjugated spe-
cies and counterions would enable the formation of dimen-
sion-controlled organized structures, such as crystals or soft
materials.[2–4] Ion pairs as components of supramolecular as-
semblies provide various modes of structural organization
according to the combination of cations and anions. Ex-
changing the components in the assemblies may then afford
a variety of ion-based electronic and optical materials.
Among ion-pair-based discrete assemblies, planar complexes
of cations and anions can also be considered as effective
subunits for the construction of highly organized structures
through stacking interactions. Planar geometries are also
suitable for the fabrication of 2D patterns on appropriate
surfaces. 3,5-Dipyrrolylpyrazoles (DPPs; e.g., 1a and 2a,
Figure 1a)[5] are potential precursor candidates for positively
charged p-conjugated units as they form planar [2+2]-type
[a] Prof. Dr. H. Maeda, K. Chigusa
College of Pharmaceutical Sciences, Ritsumeikan University
Kusatsu 525–8577 (Japan)
Fax : (+81)77-561-2659
E-mail: maedahir@ph.ritsumei.ac.jp
Figure 1. a) i) 3,5-Dipyrrolylpyrazoles (DPPs) and ii) their [2+2]-type
[b] Dr. T. Sakurai, Prof. Dr. S. Seki
ꢀ
complexes with CF3CO2 in their protonated form and b) solid-state
Department of Applied Chemistry, Graduate School of Engineering
Osaka University, Suita 565–0871 (Japan)
packing structures of i) 1a·H+ and ii) 2a·H+ as CF3CO2ꢀ salts.
[c] Prof. Dr. K. Ohta
Interdisciplinary Graduate School of Science and Technology
Shinshu University, Ueda 386–8567 (Japan)
complexes in their protonated forms (1a·H+ and 2a·H+) by
ꢀ
combination with trifluoroacetate (TFA; CF3CO2 ).[6] Al-
[d] Dr. S. Uemura
Department of Applied Chemistry and Biochemistry
Graduate School of Science and Technology
Kumamoto University, Kumamoto 860–8555 (Japan)
though DPPs are small and structurally very simple, their
[2+2]-type complexes may be envisaged as serving as con-
stituent subunits of a variety of ordered assembled struc-
tures. In our previous report,[6] [2+2]-type complexes of
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201300993.
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1a·H+ and 2a·H+ with CF3CO2 were shown to form her-
Planar [2+2]-type complexes of a-aryl-substituted DPPs
under the appropriate conditions were observed by scanning
tunneling microscopy (STM) measurements[11] at the inter-
face of a 1,2,4-trichlorobenzene (TCB) solution and a highly
oriented pyrolytic graphite (HOPG) substrate. Bright parts
and lamellar patterns in dark trough areas are ascribable to
p-conjugated core units and alkoxy side chains, respectively.
TFA-free hexadecyloxy-substituted 1 f showed an STM
image of offset dimers in a parallelogram pattern (Fig-
ure 3ai) with lattice parameters of 4.3ꢁ0.1 nm (a) and 3.3ꢁ
ringbone-like stacking assemblies in the solid state (Fig-
ure 1b). Therefore, appropriate arrangement of [2+2]-type
complexes of modified DPPs may lead to ordered structures,
such as stacked columnar assemblies, to give functional soft
materials. Herein, we report the synthesis, assembly behav-
ior, and charge-carrier transport properties of DPP deriva-
tives possessing aryl rings at the pyrrole a-positions.
Results and Discussion
a-Aryl-substituted DPPs 1b–f (Figure 1ai) were obtained in
38–78% yields from the corresponding 1,3-dipyrrolyl-1,3-
propanedione[7] by treatment with excess hydrazine in
AcOH at reflux. In addition, to examine the effect of pyr-
role b-substituents, as seen in 2a, b-fluorinated a-aryl-substi-
tuted 2b–f (Figure 1ai) were prepared from the dipyrrolyldi-
ketone derivatives through the corresponding BF2 com-
plexes.[8] Addition of TFA to solutions of the a-aryl-substi-
tuted DPPs (0.01 mm in CH2Cl2) at RT resulted in UV/Vis
spectral changes,[9] suggesting the formation of protonated
species. As observed in the a-unsubstituted derivatives, pro-
ꢀ
tonated DPPs form complexes with CF3CO2 in the bulk
state. Furthermore, the single-crystal X-ray structure of me-
thoxy-substituted 1c in the presence of TFA (1 equiv) re-
vealed the formation of unexpected tetrameric box-like
complexes held together by hydrogen bonding between the
ꢀ
pyrrole/pyrazole NH and CF3CO2 as well as between the
pyrrole/pyrazole NH and methoxy O atoms (Figure 2). The
solid-state structure of [1c·H+]
C
ꢀ
Figure 3. a) STM images (TCB, HOPG) and b) proposed model struc-
ACTHNUTRGNEUNG
tures of i) 1 f and ii) [1 f·H+][CF3CO2ꢀ]. Some of the alkyl chains that are
missing in b) can be considered to show weak interactions with the sur-
face.
ACTHNUTRGNEUNG
Figure 2. Single-crystal X-ray structure of [1c·H+][CF3CO2ꢀ] as a) a top
view and b) a side view of the tetrametric box-like complex.
ample of ion-pair-based assemblies, is far from a planar
[2+2]-type structure, presumably because of the methoxy
substituents, which act as hydrogen-bonding accepting units,
on the a-aryl moieties. The box-like complexes, possessing
inner cavities of 96 ꢁ3, form tube-like assemblies. The
single-crystal X-ray structure indicated the formation of the
0.1 nm (b; Figure 3bi).[12] On the other hand, in the presence
of TFA (1 equiv), rectangular patterns consisting of dimers
arranged in parallel were observed (Figure 3aii). The paral-
lel pairs of bright rods were in contrast to the pairs of TFA-
free 1 f. The lattice parameters of 3.7ꢁ0.3 nm (a) and 3.5ꢁ
0.3 nm (b) strongly suggested the formation of a [2+2]-type
ꢀ
ꢀ
complex of 1c·H+ and CF3CO2 in a 1:1 ratio from a mix-
assembly of [1 f·H+]
U
ture of 1c and TFA. On the other hand, longer alkoxy
chains would interfere with the formation of such a box-like
structure. In addition, aliphatic chains on the a-aryl moieties
would interact with one another, resulting in the formation
of columnar structures based on the [2+2]-type ion-pair
complexes, as discussed below.[10]
face. The observed difference between the 2D patterns of 1 f
ꢀ
and 1 f·H+ as a CF3CO2 complex was induced by protona-
tion and subsequent anion binding.
In addition to the extension of the [2+2]-type planar
structures in the direction parallel to the planes, as observed
by STM, their stacking behaviors were also examined.[13]
Longer alkyl chains attached to aryl rings can serve as van
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vealed monotropic mesophases at 84–134, 69–110, and 63–
1098C, respectively, during the heating processes. On the
ꢀ
other hand, 1 f·H+ and 2 f·H+ as CF3CO2 complexes, which
were purified as precipitates from octane,[16] exhibited enan-
tiotropic mesophases at 66–858C (M1) and 85–968C (M2;
ꢀ
ꢀ
[1 f·H+][CF3CO2 ]) and at 68–1318C ([2 f·H+]
ACHTNUTRGENNUG CAHTUNGTREN[NUGN CF3CO2 ])
during cooling processes from isotropic liquids (Iso).[17]
POM measurements of 1 f·H+ as a CF3CO2 complex also
ꢀ
suggested two types of mesophases, showing a broken-fan-
like texture and no texture for M1 and M2, respectively,
ꢀ
whereas [2 f·H+]
N
sand-like POM texture (Figure 5a). Synchrotron XRD anal-
ysis of TFA-free 2d–f showed Colh phases (Zꢂ2 for 1=1),
with a=3.04 (1108C), 3.54 (908C), and 4.00 nm (808C), re-
spectively, which were formed from disk-like units consisting
of two rod-like molecules. Furthermore, upon cooling from
ꢀ
Iso, [1 f·H+]
N
¯
Cub (Pn3m) phase, which is consistent with the POM result,
with a=10.9 nm (Figure 5bi). [1 f·H+]
808C showed a slightly complicated phase as a mixed state
Figure 4. a) Photographs (under UV365 nm light) of i) 1 f as a precipitate
and ii) 2 f as a supramolecular gel from 1,4-dioxane (20 mgmLꢀ1) exhibit-
ing the changes upon the addition of 1 equivalent of TFA, b) SEM
images of xerogels of i) [1 f·H+][CF3CO2ꢀ] and ii) [2 f·H+]
ACTHNUGTRENNUGN ACHTUNGTRENNNUG
c) synchrotron XRD pattern of [1 f·H+]
dioxane) at 258C.
ACHTUNGTRENNUNG
der Waals interaction sites, supporting the formation of co-
ACHTUNGTRENNUNGlumnar structures based on the [2+2]-type complexes. The
DPPs 1d,e and 2d,e proved to be soluble in 1,4-dioxane
both in the absence and presence of TFA, whereas 1 f
formed a precipitate. On the other hand, TFA-free 2 f, along
with 1 f·H+ and 2 f·H+ as CF3CO2 complexes, afforded 1,4-
ꢀ
dioxane gels (Figure 4a), suggesting the formation of dimen-
sion-controlled organized structures. SEM measurements of
the xerogels indicated the formation of structures with the
appearance of crumpled paper (Figure 4b).[14] Furthermore,
synchrotron XRD analysis of the xerogels of 2 f, [1 f·H+]-
ꢀ
ꢀ
ACHTUNGTRENNUNG ACHTUNGTRNEN[UGN CF3CO2 ] revealed the formation
[CF3CO2 ], and [2 f·H+]
of lamellar structures with repeat distances of 5.46, 5.46, and
5.63 nm, respectively (Figure 4c). The observed distances in
the xerogels are consistent with AM1-estimated lengths in
the long-axis directions of 2 f, 1 f·H+, and 2 f·H+ (ca. 5.7, 5.5,
and 5.7 nm, respectively),[15] suggesting that the building
units are aligned almost vertically with respect to the layer
structures.
Next, the mesophases of DPPs 1d–f and 2d–f and their
ꢀ
protonated species as CF3CO2 complexes were investigated
Figure 5. a) POM images and b) synchrotron XRD patterns with pro-
by differential scanning calorimetry (DSC) and polarized
optical microscopy (POM) measurements. In contrast to
1d–f, which show no mesophases, the DSC data for 2d–f re-
ACTHNUTRGNEUNG
posed assembling models (insets) of i) [1 f·H+][CF3CO2ꢀ] and ii) [2 f·H+]-
AHCTUNGTRENNUNG
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H. Maeda et al.
of a Colr phase (a=7.32, b=3.52 nm, Zꢂ2 for 1=1) and
another phase such as Cub. The M1 mesophase can be con-
sidered as a transient state from Cub to a crystal state at
lower temperature. These mesophases differed from the
lamelACHTUNGTRENNUNGlar structures seen in the xerogel from 1,4-dioxane and
the precipitate from octane. On the other hand, [2 f·H+]-
ꢀ
N
(a=3.91 nm at 1208C) based on a [2+2]-type complex (Z
ꢂ2 for 1=1; Figure 5bii). These observations for 1 f and 2 f
suggest anion-driven control of the assembled structures. In
ꢀ
this case, the anion (CF3CO2 ) serves as a bridging unit con-
necting two cationic p-conjugated species, resulting in the
formation of a larger planar area as a building subunit of
the columnar structures. Furthermore, the differences be-
tween 1 f and 2 f can be attributed to the planarity of the p-
conjugated systems and the differences in the dipole mo-
ments in the presence and absence of electron-withdrawing
groups.
When assembled with TFA in the bulk state, 1 f and 2 f
change not only their structural order, but also their elec-
tronic states. Analogous to the absorption spectral changes
ꢀ
in solution upon addition of TFA, [1 f·H+]
G
[2 f·H+]
[CF3CO2 ] in the solid state exhibited redshifted ab-
ꢀ
Figure 6. Conductivity transients observed for a) 1 f and [1 f·H+]-
ACHUTNGRENNUG CAHTUNGTRENNUGN
[CF3CO2ꢀ] and b) 2 f and [2 f·H+][CF3CO2ꢀ] in the solid state at RT.
sorption bands, indicating smaller band gaps than those of
1 f and 2 f alone.[9] Photoelectron yield spectroscopy of
ꢀ
ꢀ
[1 f·H+][CF3CO2 ] and [2 f·H+]
ACHTUNGTRENNUNG ACHTUNGTRNE[NUGN CF3CO2 ] in the solid state
indicated shallow HOMO energy levels of ꢀ5.3 and
ꢀ5.2 eV, respectively.[9] Based on the advantageous HOMO
energy levels and low band gap for positive-charge-conduct-
ing pathways, we performed flash-photolysis time-resolved
microwave conductivity (FP-TRMC)[18,19] measurements to
investigate the effect of ion-pair-based directional assembly
on hole mobility. This method allows us to evaluate the
local-scale motion of the photochemically generated charge-
carrier species. When photoexcited by a 355 nm laser pulse
at RT, powder samples of 1 f and 2 f on a quartz plate
showed transient conductivity, with maximum signal values
of (0.7ꢁ0.2)ꢂ10ꢀ5 and (1.1ꢁ0.2)ꢂ10ꢀ5 cm2 Vꢀ1 sꢀ1, respec-
tively (Figure 6). Upon complexation with TFA, the solid-
with TFA anions in [2+2]-type ion-pair complexes. b-Substi-
tution of DPPs can be used to control the assembly of the
[2+2]-type complexes into structures such as Cub and Colh
mesophases. Furthermore, improved charge-transfer charac-
ter has been observed for DPP units upon ion-pair complex-
ation. Protonated DPP is a useful moiety that achieves hy-
drogen-bonding-based ion-pair formation and provides
highly ordered organized structures. Even more highly or-
dered arrangement of DPP units with a view to obtaining
functional materials is currently being investigated.
Experimental Section
ꢀ
ꢀ
state structures of [1 f·H+][CF3CO2 ] and [2 f·H+]
ACHTNUTRGENNUG CAHTUNGTREN[NUGN CF3CO2 ]
exhibited higher conductivities of (1.2ꢁ0.2)ꢂ10ꢀ5 and
(1.4ꢁ0.2)ꢂ10ꢀ5 cm2 Vꢀ1 sꢀ1, respectively (Figure 6).[9] In
these cases, it was challenging to examine the electrical con-
ductivities in the mesophases, since they were susceptible to
partial loss of TFA upon heating. Considering the increase
in TRMC signals as a result of ion-pair assembly for both 1 f
and 2 f, we can conclude that directional assembly achieved
by modifying side chains and one-step ion-pair complexation
is effective for harnessing the semiconducting properties of
nonplanar p-conjugated units such as DPP.
General procedures: Starting materials were purchased from Wako Pure
Chemical Industries Ltd., Nacalai Tesque Inc., and Sigma–Aldrich Co.
and were used without further purification unless otherwise stated. UV/
Vis spectra were recorded on a Hitachi U-3500 spectrometer. Fluores-
cence spectra of solutions were recorded on a Hitachi F-4500 fluores-
cence spectrometer. NMR spectra used to characterize the products were
recorded on a JEOL ECA-600 600 MHz spectrometer. All NMR spectra
were referenced to the solvent used. Matrix-assisted laser desorption ion-
ization time-of-flight mass spectra (MALDI-TOF-MS) were recorded on
a Shimadzu Axima-CFRplus operating in negative-ion mode. TLC analy-
ses were carried out on aluminum sheets coated with silica gel 60 (Merck
5554). Fast atom bombardment mass spectrometric (FAB-MS) studies
were carried out on a JEOL-HX110 instrument in positive-ion mode by
using a 3-nitrobenzyl alcohol matrix, with the help of Prof. Tomohiro
Miyatake, Ryukoku University. Column chromatography was performed
on Sumitomo alumina KCG-1525, Wakogel C-200/C-300, or Merck silica
gel 60/60H.
Conclusion
Modified 3,5-dipyrrolylpyrazole (DPP) derivatives in their
protonated forms have been found to fabricate supramolec-
ular structures such as gels and mesophases by combining
3,5-Di(5-phenylpyrrol-2-yl)pyrazole (1b): Following a literature proce-
dure,[6] hydrazine monohydrate (450 mL, 8.73 mmol) was added to a
solution of 1,3-di(5-phenylpyrrol-2-yl)-1,3-propanedione[7] (43.0 mg,
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0.12 mmol) in AcOH (9 mL) and the mixture was stirred at reflux for
9 h. When TLC monitoring showed complete consumption of the starting
diketone, the solvent was removed and the residue was chromatographed
on a column of silica gel (Wakogel C-300; eluent: 5% MeOH/CH2Cl2).
Concentration of the appropriate fraction and recrystallization of the res-
idue from CH2Cl2/n-hexane gave 1b as a pale-yellow solid (32.9 mg,
0.094 mmol, 78%). Rf =0.28 (eluent: 5% MeOH/CH2Cl2); 1H NMR
(600 MHz, [D6]DMSO, 208C): d=12.79 (brs, 1H; pyrazole-NH), 11.40
(brs, 2H; pyrrole-NH), 7.79–7.72 (m, 4H; Ar-H), 7.41–7.33 (m, 4H; Ar-
H), 7.22–7.14 (m, 2H; Ar-H), 6.87 (s, 1H; pyrazole-CH), 6.63 (brs, 1H;
pyrrole-H), 6.59 (brs, 1H; pyrrole-H), 6.57 (brs, 1H; pyrrole-H),
6.42 ppm (brs, 1H; pyrrole-H); UV/Vis (CH2Cl2): lmax (e)=325.5 nm
(3.8ꢂ104 mꢀ1 cmꢀ1); fluorescence (CH2Cl2): lex =326 nm; lem =375,
446 nm (sh); MALDI-TOF-MS: m/z (%): calcd for C23H18N4: 350.15
[M]+; found: 350.1 (100), 351.2 (82).
OCH2CH2), 1.77–1.73 (m, 4H; OCH2CH2), 1.48–1.47 (m, 12H;
OCH2CH2CH2), 1.36–1.26 (m, 96H; OC3H6C8H16CH3), 0.89–0.87 ppm
(m, 18H; OC11H22CH3); UV/Vis (CH2Cl2): lmax (e)=329.5 nm (7.0ꢂ
104 mꢀ1 cmꢀ1); fluorescence (CH2Cl2): lex =330 nm; lem =363, 379, 501 nm;
MALDI-TOF-MS: m/z (%) calcd for C95H162N4O6: 1455.25 [M]+; found:
1455.3 (100).
3,5-Bis[5-(3,4,5-trihexadecyloxyphenyl)pyrrol-2-yl]pyrazole (1 f): Hydra-
zine monohydrate (50 mL, 1.03 mmol) was added to
a solution of
1,3-bis[5-(3,4,5-trihexadecyloxyphenyl)pyrrol-2-yl]-1,3-propanedione[7]
(89.5 mg, 0.05 mmol) in AcOH (3 mL) and the mixture was stirred at
reflux for 5 h. When TLC monitoring showed complete consumption of
the starting diketone, the solvent was removed and the residue was flash
chromatographed on a column of silica gel (eluent: 1% MeOH/CH2Cl2).
Concentration of the appropriate fraction and recrystallization of the res-
idue from CH2Cl2/MeOH gave 1 f as
a pale-yellow solid (44.0 mg,
3,5-Bis[5-(3,4,5-trimethoxyphenyl)pyrrol-2-yl]pyrazole (1c): Hydrazine
monohydrate (267 mL, 5.50 mmol) was added to a solution of 1,3-bis-
0.025 mmol, 77%). Rf =0.43 (eluent: 1% MeOH/CH2Cl2); 1H NMR
(600 MHz, CDCl3, 208C; the pyrazole-NH signal could not be observed
at this temperature because of fast proton exchange between the adja-
cent N atoms): d=9.11 (brs, 2H; pyrrole-NH), 6.70 (s, 4H; Ar-H), 6.55
(s, 1H; pyrazole-CH), 6.52 (s, 2H; pyrrole-CH), 6.45 (s, 2H; pyrrole-
CH), 4.00–3.94 (m, 12H; OCH2), 1.82–1.80 (m, 8H; OCH2CH2), 1.77–
1.72 (m, 4H; OCH2CH2), 1.47–1.46 (m, 12H; OC2H4CH2), 1.34–1.25 (m,
144H; OC3H6C12H24CH3), 0.89–0.86 ppm (m, 18H; OC15H30CH3); UV/
Vis (CH2Cl2): lmax (e)=329.0 nm (6.2ꢂ104 mꢀ1 cmꢀ1); fluorescence
(CH2Cl2): lex =330 nm; lem =381, 508 nm; MALDI-TOF-MS: m/z (%)
calcd for C119H210N4O6: 1792.63 [M+H]+; found: 1791.6 (98), 1792.6
(100).
[5-(3,4,5-trimethoxyphenyl)pyrrol-2-yl]-1,3-propanedione[7]
(115.8 mg,
0.22 mmol) in AcOH (4 mL) and the mixture was stirred at reflux for
15 h. When TLC monitoring showed complete consumption of the start-
ing diketone, the solvent was removed and the residue was flash chroma-
tographed on a column of silica gel (eluent: 2% MeOH/CH2Cl2). Con-
centration of the appropriate fraction and recrystallization of the residue
from CH2Cl2/n-hexane gave 1c as
a pale-yellow solid (49.1 mg,
0.093 mmol, 42%). Rf =0.37 (eluent: 5% MeOH/CH2Cl2); 1H NMR
(600 MHz, [D6]DMSO, 208C): d=12.83 (brs, 1H; pyrazole-NH), 11.37
(brs, 2H; pyrrole-NH), 7.05 (s, 4H; Ar-H), 6.80 (s, 1H; pyrazole-CH),
6.60 (s, 3H; pyrrole-CH), 6.43 (brs, 1H; pyrrole-CH), 3.90–3.82 (m, 12H;
OCH3), 3.77–3.72 ppm (m, 6H; OCH3); UV/Vis (CH2Cl2): lmax (e)=
4-Bromo-1,2,3-trihexadecyloxybenzene:
A mixture of K2CO3 (6.11 g,
44.2 mmol), 4-bromo-1,2,3-trihydroxybenzene[20] (1.30 g, 6.32 mmol), and
1-bromohexadecane (6.56 g, 21.5 mmol) in dry DMF (50 mL) was stirred
at reflux for 3 days. After cooling, the solvent was evaporated. The crude
product was taken up in CH2Cl2, and the solution was washed with
water, dried over MgSO4, and concentrated to dryness. The residue was
then chromatographed on a column of silica gel (Wakogel C-300; eluent:
CH2Cl2/n-hexane, 1:5) to give 4-bromo-1,2,3-trihexadecyloxybenzene as a
white solid (4.65 g, 5.29 mmol, 84%). Rf =0.45 (eluent: CH2Cl2/n-hexane,
1:5); 1H NMR (600 MHz, CDCl3, 208C): d=7.15 (d, J=9.0 Hz, 1H; Ar-
H), 6.54 (d, J=9.0 Hz, 1H; Ar-H), 4.02 (t, J=6.0 Hz, 2H; OCH2), 3.96
(t, J=6.0 Hz, 2H; OCH2), 3.92 (t, J=6.0 Hz, 2H; OCH2), 1.83–1.72 (m,
6H; OCH2CH2), 1.50–1.43 (m, 6H; OC2H4CH2), 1.34–1.25 (m, 72H;
OC3H6C12H24CH3), 0.89–0.87 ppm (m, 9H; OC15H30CH3); MALDI-TOF-
MS: m/z (%) calcd for C54H101BrO3: 876.69 [M]+; found: 876.7 (100).
329.0 nm (4.7ꢂ104 mꢀ1 cmꢀ1); fluorescence (CH2Cl2): lex =329 nm; lem
=
364, 378, 494 nm; MALDI-TOF-MS: m/z (%) calcd for C29H30N4O6:
530.22 [M]+; found: 530.2 (100), 531.2 (28).
3,5-Bis[5-(3,4,5-trioctyloxyphenyl)pyrrol-2-yl]pyrazole (1d): Hydrazine
monohydrate (1.63 mL, 33.6 mmol) was added to a solution of 1,3-bis-
[5-(3,4,5-trioctyloxyphenyl)pyrrol-2-yl]-1,3-propanedione[7]
(467 mg,
0.42 mmol) in AcOH (4 mL) and the mixture was stirred at reflux for
35 h. When TLC monitoring showed complete consumption of the start-
ing diketone, the solvent was removed and the residue was flash chroma-
tographed on a column of silica gel (eluent: 1% MeOH/CH2Cl2). Con-
centration of the appropriate fraction and recrystallization of the residue
from CH2Cl2/MeOH gave 1d as a brown solid (309.1 mg, 0.28 mmol,
67%). Rf =0.22 (eluent: 1% MeOH/CH2Cl2); 1H NMR (600 MHz,
[D6]DMSO, 208C): d=12.79 (brs, 1H; pyrazole-NH), 11.33 (brs, 1H;
pyrrole-NH), 11.27 (brs, 1H; pyrrole-NH), 7.00 (s, 4H; Ar-H), 6.80 (s,
1H; pyrazole-CH), 6.55 (s, 3H; pyrrole-CH), 6.40 (brs, 1H; pyrrole-CH),
4.02 (t, J=6.6 Hz, 8H; OCH2), 3.83 (t, J=6.0 Hz, 4H; OCH2), 1.75–1.73
(tt, J=7.8, 6.6 Hz, 8H; OCH2CH2), 1.65–1.63 (tt, J=7.8, 6.6 Hz, 4H;
OCH2CH2), 1.48–1.42 (m, 12H; OC2H4CH2), 1.36–1.26 (m, 48H;
OC3H6C4H8CH3), 0.86–0.84 ppm (m, 18H; OC7H14CH3); UV/Vis
(CH2Cl2): lmax (e)=329.5 nm (6.1ꢂ104 mꢀ1 cmꢀ1); fluorescence (CH2Cl2):
lex =329 nm; lem =363, 380, 497 nm; MALDI-TOF-MS: m/z (%) calcd
for C71H115N4O6: 1119.88 [M+H]+; found: 1119.9 (100).
1-tert-Butoxycarbonyl-2-(2,3,4-trihexadecyloxyphenyl)pyrrole
and
2-(2,3,4-trihexadecyloxyphenyl)pyrrole: A solution of Na2CO3 (1.98 g,
18.7 mmol) in water (4 mL) was added to a solution of 4-bromo-1,2,3-tri-
hexadecyloxybenzene (4.55 g, 5.18 mmol), 1-tert-butoxycarbonylpyrrole-
2-boronic acid (1.31 g, 6.22 mmol), and [PdACHTNURTGNEUNG(PPh3)4] (370.0 mg,
0.32 mmol) in 1,2-dimethoxyethane (40 mL) at RT under nitrogen. The
mixture was heated at reflux for 6 h, cooled, and then partitioned be-
tween water and CH2Cl2. The organic phase was dried over anhydrous
MgSO4 and concentrated to give an oil, which was chromatographed on
a column of silica gel (Wakogel C-300; eluent: CH2Cl2/n-hexane, 1:2) to
give 1-tert-butoxycarbonyl-2-(2,3,4-trihexadecyloxyphenyl)pyrrole (1.91 g,
1.98 mmol, 38%) as a colorless oil. Rf =0.31 (eluent: CH2Cl2/n-hexane,
1:2); 1H NMR (600 MHz, CDCl3, 208C): d=7.31–7.30 (m, 1H; pyrrole-
CH), 6.92 (d, J=9.0 Hz, 1H; Ar-H), 6.62 (d, J=8.4 Hz, 1H; Ar-H), 6.19–
6.18 (m, 1H; pyrrole-CH), 6.09–6.08 (m, 1H; pyrrole-CH), 4.00–3.94 (m,
6H; OCH2), 1.81–1.74 (m, 6H; OCH2CH2), 1.50–1.42 (m, 6H;
OC2H4CH2), 1.36 (s, 9H; Boc), 1.34–1.25 (m, 72H; OC3H6C12H24CH3),
0.89–0.86 ppm (m, 9H; OC15H30CH3); MALDI-TOF-MS: m/z (%) calcd
for C63H113NO5: 963.86 [M]+; found: 963.3 (100). The product 1-tert-bu-
toxycarbonyl-2-(2,3,4-trihexadecyloxyphenyl)pyrrole (1.91 g, 1.98 mmol)
was heated at 1908C for 30 min. The residue was then chromatographed
on a column of silica gel (Wakogel C-300; eluent: CH2Cl2/n-hexane, 1:3)
to give 2-(2,3,4-trihexadecyloxyphenyl)pyrrole as a white solid (1.24 g,
1.43 mmol, 73%). Rf =0.33 (eluent: CH2Cl2/n-hexane, 1:3); 1H NMR
(600 MHz, CDCl3, 208C): d=9.78 (s, 1H; pyrrole-NH), 7.25 (d, J=
9.0 Hz, 1H; Ar-H), 6.81–6.80 (m, 1H; pyrrole-CH), 6.67 (d, J=9.0 Hz,
3,5-Bis[5-(3,4,5-tridodecyloxyphenyl)pyrrol-2-yl]pyrazole (1e): Hydrazine
monohydrate (953 mL, 19.6 mmol) was added to a solution of 1,3-bis-
[5-(3,4,5-tridodecyloxyphenyl)pyrrol-2-yl]-1,3-propanedione[7] (817.2 mg,
0.56 mmol) in AcOH (3 mL) and the mixture was stirred at reflux for
7 h. When TLC monitoring showed complete consumption of the starting
diketone, the solvent was removed and the residue was flash chromato-
graphed on a column of silica gel (eluent: 0.5% MeOH/CH2Cl2). Con-
centration of the appropriate fraction and recrystallization of the residue
from CH2Cl2/MeOH gave 1e as a brown solid (305.8 mg, 0.21 mmol,
38%). Rf =0.20 (eluent: 0.5% MeOH/CH2Cl2); 1H NMR (600 MHz,
CDCl3, 208C; the pyrazole-NH signal could not be observed at this tem-
perature because of fast proton exchange between the adjacent N atoms;
other solvents such as [D6]DMSO make the pyrazole-NH signal more
evident, as observed for 1b–d and 2d): d=8.87 (brs, 2H; pyrrole-NH),
6.70 (s, 4H; Ar-H), 6.55 (s, 1H; pyrazole-CH), 6.52 (s, 2H; pyrrole-CH),
6.46 (s, 2H; pyrrole-CH), 4.03–3.95 (m, 12H; OCH2), 1.84–1.80 (m, 8H;
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H. Maeda et al.
1H; Ar-H), 6.46–6.45 (m, 1H; pyrrole-CH), 6.26–6.24 (m, 1H; pyrrole-
CH), 4.02–3.95 (m, 6H; OCH2), 1.84–1.73 (m, 6H; OCH2CH2), 1.51–1.39
(m, 6H; OC2H4CH2), 1.38–1.25 (m, 72H; OC3H6C12H24CH3), 0.89–
0.86 ppm (m, 9H; OC15H30CH3); MALDI-TOF-MS: m/z (%) calcd for
C58H105NO5: 863.81 [M]+; found: 863.8 (100).
MALDI-TOF-MS: m/z (%) calcd for C23H13F4N2O2: 425.09 [MꢀH]ꢀ;
found: 425.1 (100).
3,5-Bis(3,4-difluoro-5-phenylpyrrol-2-yl)pyrazole (2b): Hydrazine mono-
hydrate (10 mL, 0.21 mmol) was added to a solution of 2b’ (3.8 mg,
8.9 mmol) in AcOH (1 mL) and the mixture was stirred at reflux for 10 h.
When TLC monitoring showed complete consumption of the starting di-
ketone, the solvent was removed and the residue was flash chromato-
graphed on a column of silica gel (eluent: 3% MeOH/CH2Cl2). Concen-
tration of the appropriate fraction and recrystallization of the residue
from CH2Cl2/n-hexane gave 2b as a brown solid (2.1 mg, 5.0 mmol, 56%).
Rf =0.15 (eluent: 3% MeOH/CH2Cl2); 1H NMR (600 MHz, CDCl3,
208C; the pyrazole-NH signal could not be observed at this temperature
because of fast proton exchange between the adjacent N atoms): d=8.31
(brs, 2H; pyrrole-NH), 7.58 (d, J=7.8 Hz, 4H; Ar-H), 7.42 (t, J=7.8 Hz,
4H; Ar-H), 7.28 (d, J=7.2 Hz, 4H; Ar-H), 6.67 ppm (s, 1H; pyrazole-
CH); UV/Vis (CH2Cl2): lmax (e)=321.0 nm (3.4ꢂ104 mꢀ1 cmꢀ1); fluores-
cence (CH2Cl2): lex =321 nm; lem =374, 444 nm (sh); MALDI-TOF-MS:
m/z (%) calcd for C23H14F4N4: 423.12 [M+H]+; found: 423.1 (100).
1,3-Bis[5-(2,3,4-trihexadecyloxyphenyl)pyrrol-2-yl]-1,3-propanedione
(1g’): Malonyl chloride (62.4 mg, 0.44 mmol) was added to a solution of
2-(2,3,4-trihexadecyloxyphenyl)pyrrole (633.1 mg, 0.73 mmol) in CH2Cl2
(20 mL) at RT and the mixture was stirred for 10 min at the same tem-
perature. After TLC monitoring showed complete consumption of the
starting pyrrole, the mixture was washed with saturated aqueous Na2CO3
and water, dried over anhydrous MgSO4, filtered, and concentrated to
dryness. The residue was then chromatographed on a column of silica gel
(Wakogel C-300; eluent: CH2Cl2/n-hexane, 2:1) to give 1g’ (361.1 mg,
0.20 mmol, 55%) as an orange solid. Rf =0.30 (eluent: CH2Cl2/n-hexane,
2:1); 1H NMR (600 MHz, CDCl3, 208C; the diketone was obtained as a
mixture of keto and enol tautomers in a ratio of 1:0.41): keto form: d=
10.66 (s, 2H; pyrrole-NH), 7.28 (d, J=9.0 Hz, 2H; Ar-H), 7.11–7.10 (m,
2H; pyrrole-CH), 6.67 (d, J=9.0 Hz, 2H; Ar-H), 6.52–6.51 (m, 2H; pyr-
role-CH), 4.19 (s, 2H; CH), 4.02–3.96 (m, 12H; OCH2), 1.87–1.75 (m,
12H; OCH2CH2), 1.50–1.44 (m, 12H; OCH2CH2CH2), 1.39–1.23 (m,
144H; OC3H6C8H16CH3), 0.88–0.85 ppm (m, 18H; OC15H30CH3); enol
form: d=10.63 (s, 2H; pyrrole-NH), 7.30 (d, J=9.0 Hz, 2H; Ar-H), 6.90–
6.89 (m, 2H; pyrrole-H), 6.69 (d, J=9.0 Hz, 2H; Ar-H), 6.55–6.54 (m,
2H; pyrrole-H), 6.31 (s, 1H; CH), 4.12–4.06 (m, 12H; OCH2), 1.87–1.75
(m, 12H; OCH2CH2), 1.50–1.44 (m, 12H; OC2H4CH2), 1.39–1.23 (m,
144H; OC3H6C8H16CH3), 0.88–0.85 ppm (m, 18H; OC15H30CH3);
MALDI-TOF-MS: m/z (%) calcd for C119H210N2O8: 1795.61 [M]+; found:
1795.6 (100).
3,4,5-Trimethoxyphenylboronic acid pinacol ester: A two-necked flask
containing 5-bromo-1,2,3-trimethoxybenzene (686 mg, 2.78 mmol),
[PdCl2ACTHNUGTRNE(UGN PPh3)2] (64.4 mg, 0.03 mmol), bis(pinacolato)diboron (1.06 g,
4.17 mmol), and KOAc (818 mg, 8.34 mmol) was flushed with nitrogen
and charged with degassed 1,4-dioxane (35 mL). The mixture was heated
at 808C for 18 h, cooled, and then partitioned between water and
CH2Cl2. The organic phase was dried over anhydrous MgSO4 and concen-
trated. The residue was flash chromatographed on a column of silica gel
(eluent: 1% MeOH/CH2Cl2) to give the desired product (661 mg,
2.25 mmol, 81%) as a white solid. Rf =0.27 (eluent: 1% MeOH/CH2Cl2);
1H NMR (600 MHz, CDCl3, 208C): d=7.03 (s, 2H; Ar-H), 3.90 (s, 6H;
OCH3), 3.87 (s, 3H; OCH3), 1.34 ppm (s, 12H; pinacol-CH3); FAB-MS:
m/z (%) calcd for C15H23BO5: 294.16 [M]+; found: 294.1 (100).
3,5-Bis[5-(2,3,4-trihexadecyloxyphenyl)pyrrol-2-yl]pyrazole (1g): Hydra-
zine monohydrate (258 mL, 5.3 mmol) was added to a solution of 1g’
(106.9 mg, 0.06 mmol) in AcOH (3 mL) and the mixture was stirred at
reflux for 46 h. When TLC monitoring showed complete consumption of
the starting diketone, the solvent was removed and the residue was flash
chromatographed on a column of silica gel (eluent: CH2Cl2/n-hexane,
4:1). Concentration of the appropriate fraction and recrystallization of
the residue from CH2Cl2/MeOH gave 1g as a white solid (34.9 mg,
0.019 mmol, 33%). Rf =0.28 (eluent: CH2Cl2/n-hexane, 4:1); 1H NMR
(600 MHz, CDCl3, 208C; the pyrazole-NH signal could not be observed
at this temperature because of fast proton exchange between the adja-
cent N atoms): d=10.22 (brs, 2H; pyrrole-NH), 7.28 (d, J=8.4 Hz, 2H;
Ar-H), 6.67 (d, J=8.4 Hz, 2H; Ar-H), 6.50–6.49 (m, 2H; pyrrole-CH),
6.48–6.47 (m, 2H; pyrrole-CH), 6.44 (s, 1H; pyrazole-CH), 4.08 (t, J=
6.6 Hz, 4H; OCH2), 4.02 (t, J=6.6 Hz, 4H; OCH2), 3.98 (t, J=6.6 Hz,
4H; OCH2), 1.87–1.77 (m, 12H; OCH2CH2), 1.52–1.43 (m, 12H;
OC2H4CH2), 1.36–1.21 (m, 144H; OC3H6C12H24CH3), 0.89–0.86 ppm (m,
18H; OC15H30CH3); UV/Vis (CH2Cl2): lmax (e)=329.0 nm (1.1ꢂ
104 mꢀ1 cmꢀ1); fluorescence (CH2Cl2): lex =329 nm; lem =376 nm;
MALDI-TOF-MS: m/z (%) calcd for C119H210N4O6: 1791.63 [M]+; found:
1791.6 (100).
BF2 complex of 1,3-bis[3,4-difluoro-5-(3,4,5-trimethoxyphenyl)pyrrol-2-
yl]-1,3-propanedione (2c’’):
complex of 1,3-bis(3,4-difluoro-5-iodopyrrol-2-yl)-1,3-propanedione[8]
(146 mg, 0.25 mmol), 3,4,5-trimethoxyphenyl boronic acid pinacol ester
(185 mg, 0.63 mmol), [Pd(PPh3)4] (28.9 mg, 0.03 mmol), and Na2CO3
A two-necked flask containing the BF2
AHCTUNGTRENNUNG
AHCTUNGTRENNUNG
(489 mg, 1.50 mmol) was flushed with nitrogen and charged with DMF
(5.0 mL). The mixture was heated at reflux for 4 h, cooled, and then par-
titioned between water and CH2Cl2. The organic phase was dried over
anhydrous MgSO4 and concentrated. The residue was flash chromato-
graphed on a column of silica gel (eluent: 1% MeOH/CH2Cl2). Evapora-
tion of the solvent from the appropriate fraction gave 2c’’ (52.3 mg,
0.08 mmol, 32%) as a red solid. Rf =0.27 (eluent: 1% MeOH/CH2Cl2);
1H NMR (600 MHz, CDCl3, 208C): d=8.84 (s, 2H; pyrrole-NH), 6.88 (s,
4H; Ar-H), 6.73 (s, 1H; CH), 3.97 (s, 12H; OCH3), 3.92 ppm (s, 6H;
OCH3); UV/Vis (CH2Cl2): lmax (e)=512.0 nm (1.3ꢂ104 mꢀ1 cmꢀ1);
MALDI-TOF-MS: m/z (%) calcd for C29H24BF6N2O8: 653.15 [MꢀH]ꢀ;
found: 653.2 (100).
1,3-Bis[3,4-difluoro-5-(3,4,5-trimethoxyphenyl)pyrrol-2-yl]-1,3-propane-
dione (2c’): AlCl3 (40.0 mg, 0.30 mmol) was added to a solution of 2c’’
(19.9 mg, 0.030 mmol) in THF (6 mL) and the mixture was stirred at
reflux for 30 min. It was then cooled to RT, whereupon tert-butyl alcohol
(704 mL, 7.5 mmol) was added and the resulting mixture was stirred at
the same temperature for 10 min. Water (1.4 mL) was then added and
the mixture was stirred at the same temperature for 1 h. It was then par-
titioned between water and CH2Cl2. The organic phase was dried over
anhydrous MgSO4 and concentrated. The residue was flash chromato-
graphed on a column of silica gel (eluent: 2% MeOH/CH2Cl2) to give
2c’ (6.0 mg, 9.9 mmol, 33%) as an orange solid. Rf =0.33 (eluent: 2%
1,3-Bis(3,4-difluoro-5-phenylpyrrol-2-yl)-1,3-propanedione (2b’): AlCl3
(38.7 mg, 0.29 mmol) was added to a solution of the BF2 complex of 2b’
(2b’’)[8] (27.5 mg, 0.058 mmol) in CH2Cl2 (3 mL) and the mixture was stir-
red at reflux for 10 min. After cooling to RT, tert-butyl alcohol (1.36 mL,
14.5 mmol) was added and the resulting mixture was stirred at the same
temperature for 10 min. Water (2.72 mL) was then added and the mixture
was stirred at the same temperature for 26 h. It was then partitioned be-
tween water and CH2Cl2. The organic phase was dried over anhydrous
MgSO4 and concentrated. The residue was then chromatographed on a
column of silica gel (Wakogel C-300; eluent: 1% MeOH/CH2Cl2). Con-
centration of the appropriate fraction and removal of impurities by re-
peated rinsing with n-hexane gave 2b’ (6.0 mg, 0.014 mmol, 24%) as an
1
MeOH/CH2Cl2); H NMR (600 MHz, CDCl3, 208C; the diketone was ob-
tained as a mixture of keto and enol tautomers in a ratio of 0.71:1): keto
form: d=8.87 (brs, 2H; pyrrole-NH), 6.82 (s, 4H; Ar-H), 4.30 (s, 2H;
CH), 3.93 (s, 12H; OCH3), 3.92 ppm (s, 6H; OCH3); enol form: d=8.65
(brs, 2H; pyrrole-NH), 6.81 (s, 4H; Ar-H), 6.51 (s, 1H; CH), 3.93 (s,
12H; OCH3), 3.92 ppm (s, 6H; OCH3); MALDI-TOF-MS: m/z (%)
calcd for C29H25F4N2O8: 605.15 [MꢀH]ꢀ; found: 605.2 (100).
1
orange solid. Rf =0.27 (eluent: 1% MeOH/CH2Cl2); H NMR (600 MHz,
CDCl3, 208C; the diketone was obtained as a mixture of keto and enol
tautomers in a ratio of 0.78:1): keto form: d=8.77 (brs, 2H; pyrrole-
NH), 7.83–7.37 (m, 10H; Ar-H), 4.31 ppm (s, 2H; CH); enol form: d=
8.61 (brs, 2H; NH), 7.83–7.37 (m, 10H; Ar-H), 6.50 ppm (s, 1H; CH);
3,5-Bis[3,4-difluoro-5-(3,4,5-trimethoxyphenyl)pyrrol-2-yl]pyrazole (2c):
Hydrazine monohydrate (78 mL, 1.6 mmol) was added to a solution of 2c’
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Ion-Pair-Based Supramolecular Assemblies
FULL PAPER
(6.0 mg, 9.9 mmol) in AcOH (1 mL) and the mixture was stirred at reflux
for 29 h. When TLC monitoring showed complete consumption of the
starting diketone, the solvent was removed and the residue was chroma-
tographed on a column of silica gel (eluent: 2% MeOH/CH2Cl2). Con-
centration of the appropriate fraction and recrystallization of the residue
from CH2Cl2/MeOH gave 2c as a brown solid (1.4 mg, 2.3 mmol, 23%).
Rf =0.07 (eluent: 2% MeOH/CH2Cl2); 1H NMR (600 MHz, CDCl3,
208C; the pyrazole-NH signal could not be observed at this temperature
because of fast proton exchange between the adjacent N atoms): d=8.42
(brs, 2H; pyrrole-NH), 6.78 (s, 4H; Ar-H), 6.70 (s, 1H; pyrazole-CH),
3.92 (s, 12H; OCH3), 3.87 ppm (s, 6H; OCH3); UV/Vis (CH2Cl2): lmax
(e)=327.0 nm (5.5ꢂ104 mꢀ1 cmꢀ1); fluorescence (CH2Cl2): lex =327 nm;
lem =387 nm; MALDI-TOF-MS: m/z (%) calcd for C29H26F4N4O6: 602.18
[M]+; found: 602.2 (100).
OC3H6C4H8CH3), 0.90–0.87 ppm (m, 18H; OC7H14CH3); MALDI-TOF-
MS: m/z (%) calcd for C71H109F4N2O8: 1195.83 [M+H]+; found: 1195.8
(100).
3,5-Bis[3,4-difluoro-5-(3,4,5-trioctyloxyphenyl)pyrrol-2-yl]pyrazole (2d):
Hydrazine monohydrate (423 mL, 8.73 mmol) was added to a solution of
2d’ (116 mg, 0.097 mmol) in AcOH (0.5 mL) and the mixture was stirred
at reflux for 63 h. When TLC monitoring showed complete consumption
of the starting diketone, the solvent was removed and the residue was
flash chromatographed on a column of silica gel (eluent: 1% MeOH/
CH2Cl2). Concentration of the appropriate fraction and recrystallization
of the residue from CH2Cl2/MeOH gave 2d as a brown solid (36.5 mg,
0.031 mmol, 32%). Rf =0.15 (eluent: 1% MeOH/CH2Cl2); 1H NMR
(600 MHz, [D6]DMSO, 508C): d=13.02 (brs, 1H; pyrazole-NH), 11.23
(brs, 1H; pyrrole-NH), 11.12 (brs, 1H; pyrrole-NH), 7.00 (s, 2H; Ar-H),
6.93 (s, 2H; Ar-H), 6.77 (s, 1H; pyrazole-CH), 4.02–4.00 (m, 8H; OCH2),
3.90–3.86 (m, 4H; OCH2), 1.77–1.72 (m, 8H; OCH2CH2), 1.70–1.62 (m,
4H; OCH2CH2), 1.49–1.43 (m, 12H; OC2H4CH2), 1.36–1.27 (m, 48H;
OC3H6C4H8CH3), 0.87–0.85 ppm (m, 18H; OC7H14CH3); UV/Vis
(CH2Cl2): lmax (e)=327.5 nm (6.8ꢂ104 mꢀ1 cmꢀ1); fluorescence (CH2Cl2):
lex =328 nm; lem =385 nm; MALDI-TOF-MS: m/z (%) calcd for
C71H110F4N4O6 [M+H]+: 1191.84; found: 1191.8 (100).
3,4,5-Trioctyloxyphenylboronic acid pinacol ester: A two-necked flask
containing 5-bromo-1,2,3-trioctyloxybenzene (1.79 g, 3.30 mmol), [PdCl2-
ACHTUNGTRENNUNG(PPh3)2] (122 mg, 0.17 mmol), bis(pinacolato)diboron (1.26 g, 4.95 mmol),
and KOAc (972 mg, 9.90 mmol) was flushed with nitrogen and charged
with degassed 1,4-dioxane (45 mL). The mixture was heated at 808C for
48 h, cooled, and then partitioned between water and CHCl3. The organic
phase was dried over anhydrous MgSO4 and concentrated. The residue
was flash chromatographed on a column of silica gel (eluent: CHCl3/n-
hexane, 1:1) to give the desired product (1.78 g, 3.02 mmol, 92%) as a
colorless oil. Rf =0.17 (eluent: CHCl3/n-hexane, 1:1); 1H NMR
(600 MHz, CDCl3, 208C): d=6.99 (s, 2H; Ar-H), 4.01 (t, J=6.6 Hz, 4H;
OCH2), 3.97 (t, J=6.6 Hz, 2H; OCH2), 1.81–1.71 (m, 6H; OCH2CH2),
1.49–1.44 (m, 6H; OC2H4CH2), 1.35–1.22 (m, 24H; OC3H6C4H8), 1.33 (s,
12H; pinacol-CH3), 0.89–0.87 ppm (m, 9H; OC7H14CH3); MALDI-TOF-
MS: m/z (%) calcd for C36H65BO5: 588.49 [M+]; found: 588.5 (100).
3,4,5-Tridodecyloxyphenylboronic acid pinacol ester: A two-necked flask
containing 5-bromo-1,2,3-tridodecyloxybenzene (2.34 g, 3.30 mmol),
[PdCl2ACTHNUGTRNE(NUG PPh3)2] (122 mg, 0.17 mmol), bis(pinacolato)diboron (1.26 g,
4.95 mmol), and KOAc (972 mg, 9.90 mmol) was flushed with nitrogen
and charged with degassed 1,4-dioxane (45 mL). The mixture was heated
at 808C for 48 h, cooled, and then partitioned between water and CHCl3.
The organic phase was dried over anhydrous MgSO4 and concentrated.
The residue was flash chromatographed on a column of silica gel (eluent:
5% EtOAc/n-hexane) to give the desired product (2.39 g, 3.16 mmol,
96%) as a white solid. Rf =0.39 (eluent: CHCl3/n-hexane, 1:1); 1H NMR
(600 MHz, CDCl3, 208C): d=6.99 (s, 2H; Ar-H), 4.00 (t, J=6.6 Hz, 4H;
OCH2), 3.97 (t, J=6.6 Hz, 2H; OCH2), 1.80–1.72 (m, 6H; OCH2CH2),
1.46–1.43 (m, 6H; OC2H4CH2), 1.33 (s, 12H; pinacol-CH3), 1.31–1.28 (m,
48H; OC3H6C8H16CH3), 0.88 ppm (t, J=6.6 Hz, 9H; OC11H22CH3);
MALDI-TOF-MS: m/z (%) calcd for C36H65BO5: 756.68 [M+]; found:
756.7 (100).
BF2 complex of 1,3-bis[3,4-difluoro-5-(3,4,5-trioctyloxyphenyl)pyrrol-2-
yl]-1,3-propanedione (2d’’):
complex of 1,3-bis(3,4-difluoro-5-iodopyrrol-2-yl)-1,3-propanedione[8]
(247 mg, 0.43 mmol), 3,4,5-trioctyloxyphenyl boronic acid pinacol ester
(633 mg, 1.08 mmol), [Pd(PPh3)4] (104 mg, 0.09 mmol), and Na2CO3
A two-necked flask containing the BF2
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
(365 mg, 3.44 mmol) was flushed with nitrogen and charged with a mix-
ture of degassed 1,2-dimethoxyethane (6 mL) and water (0.6 mL). The
mixture was heated at reflux for 18 h, cooled, and then partitioned be-
tween water and CH2Cl2. The organic phase was dried over anhydrous
MgSO4 and concentrated. The residue was flash chromatographed on a
column of silica gel (eluent: CHCl3/n-hexane, 3:1) to give 2d’’ (26.7 mg,
0.02 mmol, 5%) as a red solid. The deboronated compound 2d’ was also
obtained (116 mg, 0.10 mmol, 23%; see below). Rf =0.24 (eluent: CHCl3/
n-hexane, 3:1); 1H NMR (600 MHz, CDCl3, 208C): d=8.72 (s, 2H; pyr-
role-NH), 6.83 (s, 4H; Ar-H), 6.70 (s, 1H; CH), 4.05 (t, J=6.6 Hz, 8H;
OCH2), 4.02 (t, J=6.6 Hz, 4H; OCH2), 1.88–1.74 (m, 12H; OCH2CH2),
1.52–1.46 (m, 12H; OC2H4CH2), 1.38–1.30 (m, 48H; OC3H6C4H8CH3),
0.89 ppm (t, J=6.6 Hz, 18H; OC7H14CH3); UV/Vis (CH2Cl2): lmax (e)=
518.0 nm (1.1ꢂ104 mꢀ1 cmꢀ1); MALDI-TOF-MS: m/z (%) calcd for
C71H109BF6N2O8: 1241.81 [MꢀH]ꢀ; found: 1241.8 (100).
BF2 complex of 1,3-bis[3,4-difluoro-5-(3,4,5-tridodecyloxyphenyl)pyrrol-
2-yl]-1,3-propanedione (2e’’): A two-necked flask containing the BF2
complex of 1,3-bis(3,4-difluoro-5-iodopyrrol-2-yl)-1,3-propanedione[8]
(625 mg, 1.09 mmol), 3,4,5-tridodecyloxyphenyl boronic acid pinacol ester
(2.09 g, 2.76 mmol), [PdACTHNUTRGNEU(GN PPh3)4] (254 mg, 0.22 mmol), and Na2CO3
(936 mg, 8.83 mmol) was flushed with nitrogen and charged with a mix-
ture of degassed 1,2-dimethoxyethane (15 mL) and water (1.5 mL). The
resulting mixture was heated at reflux for 17 h, cooled, and then parti-
tioned between water and CH2Cl2. The organic phase was dried over an-
hydrous MgSO4 and concentrated. The residue was flash chromatograph-
ed on a column of silica gel (eluent: CHCl3/n-hexane, 2:1) to give 2e’’
(78.8 mg, 0.05 mmol, 5%) as a red solid. The deboronated compound 2e’
was also obtained (112 mg, 0.09 mmol, 9%; see below). Rf =0.29 (eluent:
CHCl3/n-hexane, 2:1); 1H NMR (600 MHz, CDCl3, 208C): d=8.74 (s,
2H; pyrrole-NH), 6.83 (s, 4H; Ar-H), 6.70 (s, 1H; CH), 4.05 (t, J=
6.6 Hz, 4H; OCH2), 4.02 (t, J=6.6 Hz, 2H; OCH2), 1.86–1.74 (m, 12H;
OCH2CH2), 1.52–1.48 (m, 12H; OC2H4CH2), 1.38–1.26 (m, 96H;
OC3H6C8H16CH3), 0.88 ppm (t, J=6.6 Hz, 18H; OC11H22CH3); UV/Vis
(CH2Cl2): lmax (e)=518.0 nm (8.4ꢂ104 mꢀ1 cmꢀ1); MALDI-TOF-MS: m/z
(%) calcd for C95H157BF6N2O8: 1578.19 [MꢀH]ꢀ; found: 1578.2 (100).
1,3-Bis[3,4-difluoro-5-(3,4,5-trioctyloxyphenyl)pyrrol-2-yl]-1,3-propane
ACHTUNGERTNdNUNG i-
ACHTUNGTRENNUNGone (2d’): AlCl3 (14.7 mg, 0.11 mmol) was added to a solution of 2d’’
(26.7 mg, 0.021 mmol) in CH2Cl2 (3 mL) and the mixture was stirred at
reflux for 10 min. After cooling to RT, tert-butyl alcohol (490 mL,
5.23 mmol) was added and the resulting mixture was stirred at the same
temperature for 10 min. Water (0.98 mL) was then added and the mixture
was stirred at the same temperature for 26 h. It was then partitioned be-
tween water and CH2Cl2. The organic phase was dried over anhydrous
MgSO4 and concentrated. The residue was flash chromatographed on a
column of silica gel (eluent: CHCl3/n-hexane, 3:1) to give 2d’ (7.1 mg,
5.9 mmol, 28%) as an orange solid. Rf =0.13 (eluent: CHCl3/n-hexane,
3:1); 1H NMR (600 MHz, CDCl3, 208C; the diketone was obtained as a
mixture of keto and enol tautomers in a ratio of 0.81:1): keto form: d=
8.64 (brs, 2H; pyrrole-NH), 6.77 (s, 4H; Ar-H), 4.29 (s, 2H; CH), 4.03–
3.98 (m, 12H; OCH2), 1.86–1.73 (m, 12H; OCH2CH2), 1.51–1.46 (m,
12H; OC2H4CH2), 1.36–1.29 (m, 48H; OC3H6C4H8CH3), 0.90–0.87 (m,
18H; OC7H14CH3); enol form: d=8.50 (brs, 2H; NH), 6.77 (s, 4H; Ar-
H), 6.48 (s, 1H; CH), 4.03–3.98 (m, 12H; OCH2), 1.86–1.73 (m, 12H;
OCH2CH2), 1.51–1.46 (m, 12H; OC2H4CH2), 1.36–1.29 (m, 48H;
1,3-Bis[3,4-difluoro-5-(3,4,5-tridodecyloxyphenyl)pyrrol-2-yl]-1,3-pro-
ACHUTNGERNUNpG aneCAHTUGNTRENdNGUN ione (2e’): AlCl3 (33.3 mg, 0.25 mmol) was added to a solution of
2e’’ (75.0 mg, 0.050 mmol) in CH2Cl2 (3 mL) and the mixture was stirred
at reflux for 10 min. It was then cooled to RT, whereupon tert-butyl alco-
hol (1.17 mL, 12.5 mmol) was added and the resulting mixture was stirred
at the same temperature for 10 min. Water (2.34 mL) was then added
and the mixture was stirred at the same temperature for 24 h. It was then
partitioned between water and CH2Cl2. The organic phase was dried over
anhydrous MgSO4 and concentrated. The residue was flash chromato-
graphed on a column of silica gel (eluent: CHCl3/n-hexane, 3:1) to give
2e’ (54.6 mg, 0.036 mmol, 72%) as an orange solid. Rf =0.20 (eluent:
Chem. Eur. J. 2013, 00, 0 – 0
ꢀ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
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H. Maeda et al.
CHCl3/n-hexane, 3:1); 1H NMR (600 MHz, CDCl3, 208C; the diketone
was obtained as a mixture of keto and enol tautomers in a ratio of
0.77:1): keto form: d=8.63 (brs, 2H; pyrrole-NH), 6.77 (s, 4H; Ar-H),
4.29 (s, 2H; CH), 4.03–3.98 (m, 12H; OCH2), 1.85–1.73 (m, 12H;
OCH2CH2), 1.51–1.46 (m, 12H; OC2H4CH2), 1.37–1.26 (m, 96H;
OC3H6C8H16CH3), 0.89–0.86 ppm (m, 18H; OC7H14CH3); enol form: d=
8.48 (brs, 2H; pyrrole-NH), 6.77 (s, 4H; Ar-H), 6.48 (s, 1H; CH), 4.03–
3.98 (m, 12H; OCH2), 1.85–1.73 (m, 12H; OCH2CH2), 1.51–1.46 (m,
12H; OC2H4CH2), 1.37–1.26 (m, 96H; OC3H6C8H16CH3), 0.89–0.86 ppm
(m, 18H; OC7H14CH3); MALDI-TOF-MS: m/z (%) calcd for
C95H157BF6N2O8: 1532.20 [M+H]+; found: 1532.2 (100).
18H; OC15H30CH3); UV/Vis (CH2Cl2): lmax (e)=327.5 nm (4.7ꢂ
104 mꢀ1 cmꢀ1); fluorescence (CH2Cl2): lex =328 nm; lem =387 nm;
MALDI-TOF-MS: m/z (%) calcd for C119H206F4N4O6: 1864.60 [M+H]+;
found: 1864.6 (100).
Method for single-crystal X-ray diffraction analysis: Crystallographic
data for the TFA complex of dipyrrolylpyrazole are summarized in
ACTHNUTRGNEUNG
Table 1. Single crystals of [1c·H+][CF3CO2ꢀ] were obtained by vapor dif-
fusion of heptane into a solution in CH2Cl2 containing a small amount of
toluene. The crystal selected for data collection was a brown prism of ap-
proximate dimensions 0.50ꢂ0.30ꢂ0.10 mm. Data were collected at 93 K
on a Rigaku RAXIS-RAPID diffractometer by using graphite-monochro-
mated CuKa radiation (l=1.54187 ꢁ), and the structure was solved by
direct methods. Nonhydrogen atoms were refined anisotropically. The
calculations were performed by using the Crystal Structure crystallo-
graphic software package from Molecular Structure Corporation.[21]
3,5-Bis[3,4-difluoro-5-(3,4,5-tridodecyloxyphenyl)pyrrol-2-yl]pyrazole
(2e): Hydrazine monohydrate (414 mL, 8.46 mmol) was added to a solu-
tion of 2e’ (112 mg, 0.094 mmol) in AcOH (0.5 mL) and the mixture was
stirred at reflux for 64 h. When TLC monitoring showed complete con-
sumption of the starting diketone, the solvent was removed and the resi-
due was flash chromatographed on a column of silica gel (eluent: 1%
MeOH/CH2Cl2). Concentration of the appropriate fraction and recrystal-
lization of the residue from CH2Cl2/MeOH gave 2e as a brown solid
(41.3 mg, 0.027 mmol, 29%). Rf =0.18 (eluent: 1% MeOH/CH2Cl2);
1H NMR (600 MHz, CDCl3, 208C; the pyrazole-NH signal could not be
observed at this temperature because of fast proton exchange between
the adjacent N atoms): d=8.04 (brs, 2H; pyrrole-NH), 6.73 (s, 4H; Ar-
H), 6.66 (s, 1H; pyrazole-CH), 4.02 (t, J=6.0 Hz, 8H; OCH2), 3.97 (t, J=
6.0 Hz, 4H; OCH2), 1.85–1.80 (m, 8H; OCH2CH2), 1.78–1.73 (m, 4H;
OCH2CH2), 1.51–1.45 (m, 12H; OC2H4CH2), 1.37–1.26 (m, 96H;
OC3H6C8H16CH3), 0.89–0.87 ppm (m, 18H; OC11H22CH3); UV/Vis
(CH2Cl2): lmax (e)=327.0 nm (5.1ꢂ104 mꢀ1 cmꢀ1); fluorescence (CH2Cl2):
lex =327 nm; lem =386 nm; MALDI-TOF-MS: m/z (%) calcd for
C95H157BF6N2O8: 1527.20 [M+H]+; found: 1527.2 (100).
Table 1. Crystallographic details for compound [1c·H+]
[1c·H+]
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
R
formula
Mr
crystal size [mm]
crystal system
space group
a [ꢁ]
b [ꢁ]
c [ꢁ]
a [8]
C29H31N4O6·C2F3O2·H2O
664.60
0.50ꢂ0.30ꢂ0.10
tetragonal
I41/a (no. 88)
27.2555(5)
27.2555(5)
16.2957(3)
90
b [8]
90
g [8]
90
1,3-Bis[3,4-difluoro-5-(3,4,5-trihexadecyloxyphenyl)pyrrol-2-yl]-1,3-pro-
panedione (2 f’): AlCl3 (26.0 mg, 0.20 mmol) was added to a solution of
the BF2 complex of 2 f’ (2 f’’)[8] (73.5 mg, 0.039 mmol) in CH2Cl2 (3 mL)
and the mixture was stirred at reflux for 10 min. After cooling to RT,
tert-butyl alcohol (915 mL, 9.75 mmol) was added and the resulting mix-
ture was stirred at the same temperature for 10 min. Water (1.83 mL)
was then added and the mixture was stirred at the same temperature for
19 h. It was then partitioned between water and CH2Cl2. The organic
phase was dried over anhydrous MgSO4 and concentrated. The residue
was chromatographed on a column of silica gel (eluents: 8% EtOAc/n-
hexane and 5% EtOAc/n-hexane) to give 2 f’ (42.4 mg, 0.023 mmol,
27%) as an orange solid. Rf =0.27 (eluent: CHCl3/n-hexane, 3:1);
1H NMR (600 MHz, CDCl3, 208C; the diketone was obtained as a mix-
ture of keto and enol tautomers in a ratio of 0.81:1): keto form: d=8.80
(brs, 2H; pyrrole-NH), 6.78 (s, 4H; Ar-H), 4.29 (s, 2H; CH), 4.03–3.98
(m, 12H; OCH2), 1.85–1.74 (m, 12H; OCH2CH2), 1.51–1.45 (m, 12H;
OC2H4CH2), 1.36–1.23 (m, 144H; OC3H6C12H24CH3), 0.89–0.86 ppm (m,
18H; OC15H30CH3); enol form: d=8.59 (brs, 2H; pyrrole-NH), 6.77 (s,
4H; Ar-H), 6.49 (s, 1H; CH), 4.03–3.98 (m, 12H; OCH2), 1.85–1.74 (m,
12H; OCH2CH2), 1.51–1.45 (m, 12H; OC2H4CH2), 1.36–1.23 (m, 144H;
OC3H6C12H24CH3), 0.89–0.86 ppm (m, 18H; OC15H30CH3); MALDI-
TOF-MS: m/z (%) calcd for C119H206F4N2O8: 1867.57 [M]ꢀ; found: 1867.9
(100).
V [ꢁ3]
12105.5(4)
1.450
16
93(2)
1.022
63199
5556
432
1.54187
0.0756
0.1980
1.148
1calcd [gcmꢀ3
Z
T [K]
]
m
N
]
no. of reflns
no. of unique reflns
variables
l
N
R1 (I>2s(I))
wR2 (I>2s(I))
GOF
CCDC-897964 contains the supplementary crystallographic data for this
paper. These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
DFT and AM1 calculations: Ab initio and semi-empirical calculations on
the p-conjugated molecules were carried out by using the Gaussian 03
program[15] and an HP Compaq dc5100 SFF computer.
Scanning tunneling microscopy (STM): All STM investigations were car-
ried out with a Nanoscope IIIa (Veeco Instruments, Santa Barbara, CA)
at the solution/HOPG interface. Mechanically cut Pt/Ir (90:10) wires
(0.25 mm) were used as STM tips. Solutions for STM investigation (ca.
1ꢂ10ꢀ3 m) were prepared by first dropping an appropriate volume of the
original solution in CH2Cl2 into a vial. After evaporation of the CH2Cl2,
an appropriate volume of solvent (anhydrous 1,2,4-trichlorobenzene) was
dropped into the same vial. The scales of the images were calibrated
after every investigation by using the visualized lattice of the underlying
HOPG.
3,5-Bis[3,4-difluoro-5-(3,4,5-trihexadecyloxyphenyl)pyrrol-2-yl]pyrazole
(2 f): Hydrazine monohydrate (48 mL, 0.99 mmol) was added to a solution
of 2 f’ (47.1 mg, 0.03 mmol) in AcOH (0.5 mL) and the mixture was stir-
red at reflux for 24 h. When TLC monitoring showed complete consump-
tion of the starting diketone, the solvent was removed and the residue
was flash chromatographed on
a column of silica gel (eluent: 1%
MeOH/CH2Cl2). Concentration of the appropriate fraction and recrystal-
lization of the residue from CH2Cl2/MeOH gave 2 f as a brown solid
(16.7 mg, 9.0 mmol, 36%). Rf =0.36 (eluent: 1% MeOH/CH2Cl2);
1H NMR (600 MHz, CDCl3, 208C; the pyrazole-NH signal could not be
observed at this temperature because of fast proton exchange between
the adjacent N atoms): d=8.04 (brs, 2H; pyrrole-NH), 6.74 (s, 4H; Ar-
H), 6.66 (s, 1H; pyrazole-CH), 4.04–3.97 (m, 12H; OCH2), 1.85–1.81 (m,
8H; OCH2CH2), 1.78–1.73 (m, 4H; OCH2CH2), 1.50–1.48 (m, 12H;
OC2H4CH2), 1.38–1.26 (m, 144H; OC3H6C12H24CH3), 0.89–0.86 ppm (m,
Scanning electron microscopy (SEM): SEM images were obtained with a
Hitachi S-4800 scanning electron microscope at an acceleration voltage
of 10 kV by using a silicon (100) substrate. A platinum coating was ap-
plied by using a Hitachi E-1030 ion sputter apparatus.
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ꢀ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 0000, 00, 0 – 0
ÝÝ
These are not the final page numbers!

Ion-Pair-Based Supramolecular Assemblies
FULL PAPER
Differential scanning calorimetry (DSC): The phase-transition points
were observed by means of differential scanning calorimetry (Perkin–
Elmer Diamond DSC).
Prof. Atsuhiro Osuka and Tomohiro Higashino, Kyoto University, for
single-crystal X-ray analysis, Dr. Noboru Ohta, JASRI/SPring-8, for syn-
chrotron XRD analysis, Dr. Takashi Nakanishi, NIMS, for SEM measure-
ments, Prof. Norimitsu Tohnai, Osaka University, for the estimation of
the solid-state cavity, Prof. Tomonori Hanasaki, Ritsumeikan University,
for DSC and POM measurements, and Prof. Hitoshi Tamiaki, Ritsumei-
kan University, for various measurements.
Polarizing optical microscopy (POM): POM measurements were carried
out with a Nikon OPTIPHOT-POL polarizing optical microscope equip-
ped with a Mettler FP82 HT hot stage.
Synchrotron X-ray diffraction analysis (XRD): High-resolution XRD
analyses were carried out by using a synchrotron radiation X-ray beam
with a wavelength of 1.00 ꢁ on BL40B2 at SPring-8 (Hyogo, Japan). A
large Debye–Scherrer camera with camera lengths of 535.481 mm for
XRD of 2 f (solid (from CH2Cl2/MeOH), Figure S16b in the Supporting
Information), VT-XRD of 2 f (Figure S17c in the Supporting Informa-
[1] Selected books and a review: a) Supramolecular Polymers (Ed.: A.
Ciferri), Marcel Dekker, New York, 2000; b) G. A. Ozin, A. C. Ar-
senault, Nanochemistry: A Chemical Approach to Nanomaterials,
RSC, Cambridge, 2005; c) Topics in Current Chemistry, Vol. 258, Su-
pramolecular Dye Chemistry (Ed.: F. Wꢃrthner), Springer, Berlin,
2005, pp. 1–324; d) S. S. Babu, S. Prasanthkumar, A. Ajayaghosh,
Angew. Chem. 2012, 124, 1800–1810; Angew. Chem. Int. Ed. 2012,
51, 1766–1776.
[2] Selected reviews of ionic liquid crystals: a) K. Binnemans, Chem.
Rev. 2005, 105, 4148–4204; b) T. Kato, N. Mizoshita, K. Kishimoto,
Angew. Chem. 2006, 118, 44–74; Angew. Chem. Int. Ed. 2006, 45,
38–68.
[3] Selected examples of ionic liquid crystals: a) T. Ichikawa, M.
Yoshio, A. Hamasaki, T. Mukai, H. Ohno, T. Kato, J. Am. Chem.
Soc. 2007, 129, 10662–10663; b) H. Shimura, M. Yoshio, K. Hoshi-
no, T. Mukai, H. Ohno, T. Kato, J. Am. Chem. Soc. 2008, 130, 1759–
1765; c) K. Goossens, K. Lava, P. Nockemann, V. Van Hecke, L. Van
Meervelt, K. Driesen, C. Gçrller-Walrand, K. Binnemans, T. Cardi-
naels, Chem. Eur. J. 2009, 15, 656–674; d) K. Lava, K. Binnemans,
T. Cardinaels, J. Phys. Chem. B 2009, 113, 9506–9511; e) X. H.
Cheng, X. Q. Bai, S. Jing, H. Ebert, M. Prehm, C. Tschierske, Chem.
Eur. J. 2010, 16, 4588–4601; f) J.-H. Olivier, F. Camerel, G. Ulrich, J.
Barberꢄ, R. Ziessel, Chem. Eur. J. 2010, 16, 7134–7142; g) S.
Yazaki, M. Funahashi, J. Kagimoto, H. Ohno, T. Kato, J. Am. Chem.
Soc. 2010, 132, 7702–7708; h) T. Ichikawa, M. Yoshio, A. Hamasaki,
J. Kagimoto, H. Ohno, T. Kato, J. Am. Chem. Soc. 2011, 133, 2163–
2169.
[4] Soft materials based on charge-balanced assemblies of cations and
anions: a) Y. Haketa, S. Sasaki, N. Ohta, H. Masunaga, H. Ogawa,
N. Mizuno, F. Araoka, H. Takezoe, H. Maeda, Angew. Chem. 2010,
122, 10277–10281; Angew. Chem. Int. Ed. 2010, 49, 10079–10083;
b) H. Maeda, K. Naritani, Y. Honsho, S. Seki, J. Am. Chem. Soc.
2011, 133, 8896–8899; c) B. Dong, Y. Terashima, Y. Haketa, H.
Maeda, Chem. Eur. J. 2012, 18, 3460–3463; d) Y. Haketa, Y.
Honsho, S. Seki, H. Maeda, Chem. Eur. J. 2012, 18, 7016–7020;
e) B. Dong, T. Sakurai, Y. Honsho, S. Seki, H. Maeda, J. Am. Chem.
Soc. 2013, 135, 1284–1287.
ACHTUNGTRENNUNG
tion) and [2 f·H+][CF3CO2ꢀ] (precipitate, Figure S19b in the Supporting
ꢀ
Information); 532.704 mm for VT-XRD of [2 f·H+]
ACHTUGNTRENN[UG CF3CO2 ] (Fig-
ure S19c in the Supporting Information); 531.034 mm for XRD of 1 f
(solid (from 1,4-dioxane), Figure S16a in the Supporting Information),
VT-XRD of 2d (Figure S17a in the Supporting Information), 2e (Fig-
ure S17b in the Supporting Information), and 2 f (xerogel, Figure S17d in
ꢀ
the Supporting Information); 531.679 mm for XRD of [1 f·H+]
[CF3CO2
]
(xerogel, Figure S18a in the Supporting Information) and [2 f·H+]-
ꢀ
G
]
(xerogel, Figure S19a in the Supporting Information);
541.500 mm for VT-XRD of [1 f·H+]
porting Information); and 540.180 mm for XRD of [1 f·H+]
(precipitate, Figure S18b in the Supporting Information) and VT-XRD of
[1 f·H+][CF3CO2ꢀ) (Figure S18d–f in the Supporting Information) for the
ACHTUNGTRENNUNG
ꢀ
AHCTUNGETRG[NNUN CF3CO2 ]
ACHTUNGTRENNUNG
heating process by using a quartz capillary were used with an imaging
plate as a detector. The diffraction pattern was obtained with a 0.018 step
in 2q. The exposure time to the X-ray beam was 10–60 s.
Photoelectron yield spectroscopy (PYS): The highest occupied molecular
orbital (HOMO) was estimated by UV photoelectron yield spectroscopy
(PYS). PYS measurements were performed on a Sumitomo Heavy Indus-
try model PCR-102 spectrometer, with the photon energy being adjusted
from 4.0 to 7.0 eV in increments of 0.1 eV. Thin-film samples were pre-
pared from [1 f·H+][CF3CO2ꢀ] and [2 f·H+][CF3CO2ꢀ] smeared on ITO-
ACHTUNGTRENNUNG ACHTUNGTRENNUGN
coated glass plates and loaded into the vacuum chamber evacuated to
about 5ꢂ10ꢀ4 Pa. An anode was installed beside the sample holder to
collect electrons emitted from the respective films. A deuterium lamp
was used as an excitation source and the anode voltage was fixed at 10 V.
The threshold photon energy was estimated from the photoelectron yield
spectrum.
Flash-photolysis time-resolved microwave conductivity (FP-TRMC):
Charge carrier mobility was measured by the FP-TRMC technique. Sam-
ples were prepared by attaching solid 1 f, [1 f·H+]
[CF3CO2ꢀ], 2 f, and
ꢀ
[2 f·H+]
[CF3CO2
]
to
a
quartz plate with double-sided sticky tape.
Charge carriers were photochemically generated by using the third har-
monic (l=355 nm) of a Spectra Physics model GCR-130 Nd:YAG laser
with a pulse duration of 5–8 ns. The photon density of a 355 nm pulse
was 0.9ꢂ1016 photonscmꢀ2. The microwave frequency and power were
set at ꢂ9.1 GHz and 3 mW, respectively. The TRMC signal, picked up
by a diode (rise time <1 ns), was monitored by a Tektronics model
TDS3052B digital oscilloscope. The observed conductivities were nor-
malized, and are given in terms of the photocarrier generation yield (f)
multiplied by the sum of the charge carrier mobilities (Sm), according to
Equation (1), in which e, A, I0, Flight, Pr, and DPr are the unit charge of a
single electron, a sensitivity factor [Sꢀ1 cm], the incident photon density
of the excitation laser [photoncmꢀ2], a correction (or filling) factor
[cmꢀ1], and the reflected microwave power and its change, respectively.
The experiments were carried out at RT.
[5] B. Oddo, C. Dainotti, Gazz. Chim. Ital. 1912, 42, 716–726.
[6] H. Maeda, Y. Ito, Y. Kusunose, T. Nakanishi, Chem. Commun. 2007,
1136–1138.
[7] H. Maeda, Y. Haketa, T. Nakanishi, J. Am. Chem. Soc. 2007, 129,
13661–13674.
[8] a) H. Maeda, Y. Ito, Inorg. Chem. 2006, 45, 8205–8210; b) Y.
Haketa, S. Sakamoto, K. Chigusa, N. Nakanishi, H. Maeda, J. Org.
Chem. 2011, 76, 5177–5184.
[9] See the Supporting Information.
[10] a) See the Supporting Information for crystallographic details;
b) the volume of the cavity was estimated by using the software
PLATON/VOID, A. L. Spek, Acta Crystallogr. Sect. D 2009, 65,
148–155.
[11] A review and selected articles on STM: a) S.-S. Li, B. H. Northrop,
Q.-H. Yuan, L.-J. Wan, P. J. Stang, Acc. Chem. Res. 2009, 42, 249–
259; b) A. Ciesielski, S. Lena, S. Masiero, G. P. Spada, P. Samorꢅ,
Angew. Chem. 2010, 122, 2007–2010; Angew. Chem. Int. Ed. 2010,
49, 1963–1966; c) D. Gonzꢄlez-Rodrꢆguez, P. G. A. Janssen, R.
Martꢆn-Rapffln, I. De Cat, S. De Feyter, A. P. H. J. Schenning, E. W.
Meijer, J. Am. Chem. Soc. 2010, 132, 4710–4719.
ꢀSm ¼ ð1=eAI0FlightÞðDPr=PrÞ
ð1Þ
Acknowledgements
This work was supported by PRESTO/JST (2007–2011), Grants-in-Aid
for Young Scientists (B; No. 21750155) and (A; No. 23685032) from the
MEXT, and the Ritsumeikan R-GIRO project (2008–2013). We thank
[12] The self-assembled dimer is constructed through intermolecular hy-
drogen-bonding and dipole–dipole interactions between two mole-
Chem. Eur. J. 2013, 00, 0 – 0
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H. Maeda et al.
cules of 1 f in the appropriate conformation. See the Supporting In-
formation.
mi, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng,
A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson, W.
Chen, M. W. Wong, C. Gonzalez, J. A. Pople, Gaussian, Inc., Wall-
ingford CT, 2004.
[13] The derivative 1g bearing hexadecyloxy chains at the 2,3,4-positions
did not show the formation of a [2+2]-type complex and a columnar
structure in the presence of 1 equivalent of TFA because of intramo-
lecular hydrogen bonding between the ortho-alkoxy-O and the pyr-
role NH groups.
ꢀ
ꢀ
[16] Precipitates of [1 f·H+] and [2 f·H+]
ACTHUNGTERN[NNUG CF3CO2 ] ACHTUNGERTNN[GUN CF3CO2 ] from
octane form lamellar structures with repeat distances of 5.39 and
5.40 nm, respectively, corresponding to the lengths of the [2+2]-type
complexes.
[14] Similar morphologies have been observed: A. Gopal, R. Varghese,
A. Ajayaghosh, Chem. Asian J. 2012, 7, 2061–2067.
[17] It is challenging to prepare purified samples of 1d,e and 2d,e as 1:1
complexes with TFA, suggesting that 1 f and 2 f are appropriate
building subunits of the assemblies in combination with TFA.
[18] a) A. Saeki, S. Seki, T. Sunagawa, K. Ushida, S. Tagawa, Philos.
Mag. 2006, 86, 1261–1276; b) A. Saeki, Y. Koizumi, T. Aida, S. Seki,
Acc. Chem. Res. 2012, 45, 1193–1202.
[19] S. Prasanthkumar, A. Saeki, S. Seki, A. Ajayaghosh, J. Am. Chem.
Soc. 2010, 132, 8866–8867.
[20] D. Pla, F. Albericio, Eur. J. Org. Chem. 2007, 1921–1924.
[21] CrystalStructure, Version 3.8, Single-Crystal Structure Analysis Soft-
ware, Rigaku/MSC and Rigaku Corporation, 2006.
[15] Gaussian 03, Revision C.01, M. J. Frisch, G. W. Trucks, H. B. Schle-
gel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomer-
y, Jr., T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S. Iyen-
gar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N.
Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K.
Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda,
O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian,
J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E.
Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W.
Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J.
Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D. Daniels, M. C.
Strain, O. Farkas, D. K. Malick, A. D. Rabuck, K. Raghavachari,
J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford, J. Cio-
slowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaro-
Received: March 15, 2013
Published online: && &&, 0000
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Ion-Pair-Based Supramolecular Assemblies
FULL PAPER
Supramolecular ion-pair assemblies:
Modified 3,5-dipyrrolylpyrazole (DPP)
derivatives in their protonated form
produce planar [2+2]-type complexes
with trifluoroacetate ions as the con-
stituent components of ion-pair-based
assemblies. An essential strategy for
the construction of dimension-control-
led organized structures based on the
[2+2]-type complexes is the introduc-
tion of aryl rings bearing long alkyl
chains, which enables the formation of
2D patterns at interfaces, supramolecu-
lar gels, and mesophases (see figure).
Supramolecular Chemistry
H. Maeda,* K. Chigusa, T. Sakurai,
K. Ohta, S. Uemura, S. Seki &&&& — &&&&
Ion-Pair-Based Assemblies Comprising
Pyrrole–Pyrazole Hybrids
Chem. Eur. J. 2013, 00, 0 – 0
ꢀ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
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