Control of the solid-state chiral optical properties of a supramolecular organic fluorophore containing 4-(2-Arylethynyl)-benzoic acid

Article abstract of DOI:10.1002/asia.201000780

The solid-state chiral optical properties of a 4-(2-arylethynyl)-benzoic acid/amine supramolecular organic fluorophore can be controlled by changing the arylethynyl group of the achiral 4-(2-arylethynyl)-benzoic acid component molecule rather than the chirality of the amine component molecule. So solid crew: The solid-state CD and CPL properties of a 4-(2-arylethynyl)-benzoic acid/amine supramolecular organic fluorophore can be controlled by changing the arylethynyl group of the achiral 4-(2-arylethynyl)-benzoic acid component molecule.

Full text of DOI:10.1002/asia.201000780

FULL PAPERS
DOI: 10.1002/asia.201000780
Control of the Solid-State Chiral Optical Properties of a Supramolecular
Organic Fluorophore Containing 4-(2-Arylethynyl)-Benzoic Acid
Noriaki Nishiguchi,[a] Takafumi Kinuta,[a] Yoko Nakano,[b] Takunori Harada,[c]
Nobuo Tajima,[d] Tomohiro Sato,[a] Michiya Fujiki,[b] Reiko Kuroda,[c]
Yoshio Matsubara,*[a] and Yoshitane Imai*[a]
Abstract: The solid-state chiral optical properties of a 4-(2-arylethynyl)-benzoic
Keywords: chirality
·
circular
acid/amine supramolecular organic fluorophore can be controlled by changing the
arylethynyl group of the achiral 4-(2-arylethynyl)-benzoic acid component mole-
cule rather than the chirality of the amine component molecule.
dichroism circularly polarized
·
luminescence · crystal-engineering ·
fluorescence
Introduction
can be easily controlled by changing the component mole-
cules.[2] Furthermore, most of the previously reported supra-
molecular organic fluorophores do not exhibit chirality, and
therefore do not show solid-state chiral optical properties,
such as solid-state circular dichroism (CD) and circularly
polarized luminescence (CPL).
The solid-state optical property of organic compounds is a
very important property in the development of new func-
tional organic materials. In particular, solid-state organic flu-
orophores have attracted considerable attention in the field
of optoelectronics for applications in organic electrolumines-
cence (EL) devices and optical sensors.[1] Thus far, many
solid-state organic fluorophores have been reported that are
composed of a single organic molecule. However, recently,
two-component supramolecular organic fluorophores have
been attracting attention because their optical properties
We recently developed a solid-state p-conjugated chiral
supramolecular organic fluorophore that was composed of
chiral 1-phenylethylamine (1) as the chiral unit and 4-[2-(4-
methylphenyl)ethynyl]-benzoic acid (2) as the p-conjugated
fluorescent unit.[3] The structural characteristics of this chiral
supramolecular organic fluorophore is that it is composed of
a 21-helical columnar hydrogen-bonded and ionic-bonded
network structure formed by the association of the carboxyl-
ate oxygen of a carboxylic acid anion with the ammonium
hydrogen of a protonated amine. In addition, this fluoro-
phore typically exhibits stronger solid-state CPL on com-
plexation. In general, molecules are more-rigidly constrain-
ed in the solid state than in the solution state because of the
greater influence of neighboring molecules in the solid state.
This influence affords another characteristic of solid-state
two-component supramolecular organic fluorophores, with
novel functionality resulting from synergy of the two-com-
ponent molecules. Thus, it is expected that the chiral optical
properties of two-component supramolecular organic fluoro-
phores can be controlled by changing the packing structure
of the complex. Usually, to control the sign of the chiral op-
tical properties, a chiral compound with opposite chirality is
used. However, chiral compounds with opposite chiralities
may not be easily available. Therefore, controlling the sign
of the chiral optical properties of a chiral fluorophore with-
[a] N. Nishiguchi, T. Kinuta, T. Sato, Prof. Dr. Y. Matsubara, Dr. Y. Imai
Department of Applied Chemistry
Faculty of Science and Engineering, Kinki University
3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502 (Japan)
Fax : (+81)6-6727-2024
E-mail: y-imai@apch.kindai.ac.jp
y-matsu@apch.kindai.ac.jp
[b] Y. Nakano, Prof. Dr. M. Fujiki
Graduate School of Materials Science
Nara Institute of School and Technology
Takayama, Ikoma, Nara, 630-0192 (Japan)
[c] Dr. T. Harada, Prof. Dr. R. Kuroda
Department of Life Sciences
Graduate School of Arts and Sciences
The University of Tokyo
3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan)
[d] Dr. N. Tajima
Computational Materials Science Center
National Institute for Materials Science
1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)
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Chem. Asian J. 2011, 6, 1092 – 1098

out using a chiral compound with opposite chirality is instru-
mental in the development of novel chiral fluorescent sys-
tems.
emission wavelength.[4] Hence, the HOMO–LUMO gaps of
2, 3, and 4 in the isolated state were studied theoretically.
The theoretically calculated HOMO–LUMO gaps of the
gas-phase molecules of 2, 3, and 4 were 3.98, 4.04, and
3.98 eV, respectively; these HOMO–LUMO gaps have a
similar value.
However, the values of the solid-state lem of the com-
plexes differ according to the type of 4-(2-arylethynyl)-ben-
zoic acid. The solid-state lem decreases in the order: II
(lem =423 nm)>III (lem =416 nm)>I (lem =379 nm). This
trend indicates that in this fluorescent system, the difference
in solid-state lem, which depends on the type of arylethynyl
group, may have been mainly caused by the difference in
the crystal packing of these complexes.
In order to study the trends in the solid-state chiral opti-
cal properties (CD and CPL properties) of 4-(2-arylethyn-
yl)-benzoic acid/amine supramolecular fluorophore, the
solid-state CD spectra of fluorescent complexes II and III
were measured using KBr pellets; these were also used for
similar measurements in the case of complex I. The solid-
state CD and absorption spectra of complexes I,[3] II, and III
(black lines) are shown in Figure 1.
Herein, we report the control of the solid-state chiral opti-
cal properties of a chiral two-component supramolecular or-
ganic fluorophore—4-(2-arylethynyl)-benzoic acid/amine
supramolecular fluorophore—by changing the type of the
arylethynyl group in the achiral 4-(2-arylethynyl)-benzoic
acid component molecule, and not the chirality of the chiral
amine component molecule. (R)-(+)-1-phenylethylamine
[(R)-1] was used as the chiral amine component molecule.
Two types of 4-(2-arylethynyl)-benzoic acids—4-[2-(4-fluoro-
phenyl)ethynyl]-benzoic acid (3) and 4-[2-(4-bromopheny-
l)ethynyl]-benzoic acid (4)—that contain different substitu-
ents were used as the achiral 4-(2-arylethynyl)-benzoic acid
component molecule in place of 2.
The shapes of the CD spectra are similar. Characteristic
peaks of the ethynylphenylene unit are observed between
Results and Discussion
294 and 323 nm. The circular anisotropy factors, jgCD
=
DOD/ODj, of the last Cotton effect (lCD =320 nm for I,
313 nm for II, and 323 nm for III) for I, II, and III are ap-
proximately 1.0ꢁ10ꢀ3, 4.1ꢁ10ꢀ3, and 1.5ꢁ10ꢀ3, respectively.
In order to check whether complexes I–III introduced any
artifacts into the spectrum, complexes I’–III’ were prepared
in which (R)-1 was replaced with (S)-(ꢀ)-1-phenylethyla-
mine, (S)-1. The solid-state CD spectra of complexes I’,[3] II’,
and III’ were then measured (Figure 1, gray lines). These
CD spectra were found to be mirror images of the CD spec-
tra of complexes I–III, which indicates that effective chiral
transfer occurs from chiral 1 to complexes II and III through
complexation, as in the case of complex I.
The (R)-1/3 [or (R)-1/4] chiral supramolecular organic fluo-
rophore was prepared by crystallization from an ethanol
(EtOH) solution in the same manner as that used for the
preparation of (R)-1/2 supramolecular organic fluorophore
I. (R)-1 and 3 (or 4) were dissolved in ethanol and left to
stand at room temperature. After a week, a large number of
crystals of II, composed of (R)-1 and 3 (or crystals of III
composed of (R)-1 and 4) were obtained.
The most-serious complication associated with solid-state
organic fluorophores is the occurrence of fluorescence
quenching in the crystalline state. In order to study the
solid-state optical properties of obtained complexes II and
III, their solid-state fluorescence spectra were first mea-
sured. Both complexes exhibited fluorescence. The solid-
state fluorescence maximum (lem) of complex II was ob-
served at 423 nm, and the absolute value of the photolumi-
nescence quantum yield (FF) was 0.32 in the solid state. On
the other hand, the solid-state lem and FF of complex III
were 416 nm and 0.21, respectively. In both the complexes,
the solid-state lem value shifted to a longer wavelength rela-
tive to that of complex I (lem =379 nm). It is well known
that a small HOMO–LUMO gap induces a red shift of the
Interestingly, the signs of the CD spectra of chiral com-
plexes I–III (or I’–III’) were different to one another, even
though they are composed of amine component molecules
with the same chirality. That is, the signs of the CD spectra
of complexes I and III at the longest wavelength are positive
(+; Figure 1a and c, black lines) whereas that of complex II
is negative (ꢀ; Figure 1b, black lines). This observation
shows that the solid-state CD property of 4-(2-arylethynyl)-
benzoic acid/amine supramolecular organic fluorophore can
be controlled by changing the arylethynyl unit in the achiral
4-(2-arylethynyl)-benzoic acid component molecule.
To study the origin of the solid-state CD property of
these complexes, X-ray crystallographic analyses of com-
plexes II and III were carried out, and the crystal structures
of complexes I,[3] II, and III were compared. The crystal
structure of I is shown in Figure 2. The stoichiometry of I is
(R)-1/2=1:1, and its space group is P21. This complex has a
characteristic 21-helical columnar network structure along
the b axis (Figure 2a and 2b). This column is mainly com-
posed of the carboxylate oxygen atoms from the carboxylic
Abstract in Japanese:
Chem. Asian J. 2011, 6, 1092 – 1098
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Y. Matsubara, Y. Imai et al.
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Figure 2. Crystal structure of I. a) 21-helical columnar network structure
observed along the b axis. Solid arrows A indicate the intracolumnar ben-
zene–benzene edge-to-face interactions. b) View along the a axis. c) Pack-
ing structure along the b axis. Solid arrows B–D indicate the intercolum-
nar benzene-benzene edge-to-face interactions. d) View along the a axis.
The crystal structure of II is shown in Figure 3. The stoi-
chiometry of II is (R)-1/3=1:1, and its space group is
P212121. This complex also has a 21-helical columnar network
structure along the a axis, as in complex I (Figure 3a and
3b). In complex II, intracolumnar benzene–benzene edge-
to-face interactions (2.94 ꢂ, indicated by solid arrows A in
Figure 3a) between the hydrogen atom of the benzene ring
in 3 and the benzene ring of (R)-1 were also observed.[5] II
was formed by the self-assembly of these 21-helical columns
through three intercolumnar benzene–benzene edge-to-face
interactions (2.81, 2.76, and 2.79 ꢂ, Figure 3a, solid arrows
B–D, respectively, and Figure 3b).[5] In addition, two inter-
columnar F···H interactions (2.60 ꢂ; indicated by solid
arrows E and F, in Figure 3a) were also observed.[5] Interest-
Figure 1. CD and absorption spectra of complexes a) I, b) II, and c) III
(black lines) and complexes I’–III’ (gray lines) in the solid state (KBr pel-
lets).
acid anions and the ammonium hydrogen atoms from the
protonated amines. Moreover, the intracolumnar benzene–
benzene edge-to-face interactions (2.96 ꢂ, Figure 2a, solid
arrows A) between the hydrogen atom of the benzene ring
in 2 and the benzene ring of (R)-1 are also observed.[5] I is
formed by the self assembly of these 21-helical columns by
three intercolumnar benzene–benzene edge-to-face interac-
tions (2.93, 2.73, and 2.75 ꢂ; indicated by Figure 2c, solid
arrows B–D, and Figure 2d).[5]
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Solid-State Chiral Optical Properties of a Supramolecular Organic Fluorophore
Figure 4. Crystal structure of III. a) Packing structure of 21-helical colum-
nar network structure observed along the b axis. Solid arrows A indicate
the intracolumnar benzene–benzene edge-to-face interactions. Solid
arrows B–D indicate the intercolumnar benzene–benzene edge-to-face
interactions. Solid arrow E indicates the intercolumnar Br···H interaction.
b) View along the a axis.
Figure 3. Crystal structure of II. a) Packing structure of 21-helical colum-
nar network structure observed along the a axis. Solid arrows A indicate
the intracolumnar benzene–benzene edge-to-face interactions. Solid
arrows B–D indicate the intercolumnar benzene–benzene edge-to-face
interactions. Solid arrows E and F indicate intercolumnar F···H interac-
tions. (b) View along the b axis.
gate the origin of the observed CD intensities, the excited
states of the molecular pairs of 2 and 3 in crystals I and II,
respectively, were calculated theoretically. For this purpose,
the nearest molecular pairs were selected, as shown in
Figure 5, and their excitation energies and rotational
strengths were calculated by Zernerꢃs intermediate neglect
of differential overlap (ZINDO) method using the Gaussian
03 program.[10] Table 1 lists the calculated properties of the
ingly, X-ray crystallographic analyses revealed that although
the structures of the 21-helical columns in complexes I and
II are the same, the packing structures of the shared 21-heli-
cal columns are considerably different (indicated by solid
rectangles in Figure 2d and 3b).
The crystal structure of III is shown in Figure 4. The stoi-
chiometry of III is (R)-1/4=1:1, and its space group is P21,
which is the same as that of complex I. The shared 21-helical
columnar network structure, formed by intracolumnar ben-
zene–benzene edge-to-face interactions (2.93 ꢂ, Figure 4a,
solid arrows A), was observed in this complex (Figure 4a
and 4b).[5] As expected, the packing structures of the shared
21-helical columns in complexes I and III were identical
(rectangles in Figure 2d and 4b); on the other hand, those
in complexes II and III were different (rectangles in Fig-
ure 3b and 4b). In III, there are three intercolumnar ben-
zene–benzene edge-to-face interactions between the 21-heli-
cal columns (2.97, 2.73, and 2.71 ꢂ, Figure 4a, solid arrows
B–D, respectively, and Figure 4b).[5] In addition, one inter-
columnar Br···H interaction (3.00 ꢂ; Figure 4a, solid arrow
E) were also observed.[5]
Complexes I and II have a set of positive and negative
CD intensities in 250–330 nm, which originate from the elec-
tronic absorption in this region of molecules 2 and 3, respec-
tively. CD intensities of this type are likely to arise from the
coupling of monomer electronic transitions between the
neighboring molecules in crystals. The CD intensity of com-
plex I in this wavelength region is +/ꢀ from the longer-
wavelength side whereas that of complex II has the opposite
sign; i.e., ꢀ/+ from the longer-wavelength side. To investi-
Figure 5. Molecular pairs in a) complex I and b) complex II whose excit-
ed states were calculated theoretically (indicated by arrows).
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Y. Matsubara, Y. Imai et al.
FULL PAPERS
Table 1. Calculated excited states of monomer molecules of 2 and 3 and
their molecular dimers in complexes I and II, respectively.[a]
E [eV] l [nm]
f
R x10ꢀ40 [erg esu cm Gaussꢀ1
]
Complex I
Monomer[b]
3.71
333.8
328.9
327.2
330.7
327.3
0.3207
0.2077
0.3885
0.4165
0.1961
71.3
86.2
51.0
237.4
ꢀ61.5
Dimer A–B[c] 3.77
3.79
Dimer B–C[c] 3.75
3.79
Complex II
Monomer[b]
3.67
337.9
332.3
329.9
333.7
330.3
333.8
330.4
0.2939
0.0196
0.5585
0.6020
0.0721
34.6
ꢀ47.9
128.6
23.6
Dimer A–B[c] 3.73
3.76
Dimer B–C[c] 3.72
3.75
66.4
Dimer A–D[c] 3.71
3.75
0.0212 ꢀ187.2
0.5152 216.4
[a] E=excitation energy, l=excitation wavelength, f=oscillator strength
(dimensionless), R=rotational strength. [b] The strongest electronic tran-
sition of monomer molecules, which correspond to the electronic absorp-
tion bands of complexes I and II, occur in the 250–330 nm region. The
molecular geometries of the respective crystals were used in the calcula-
tions. [c] Excited states of molecular dimers that arise from the coupling
of monomer electronic transitions. See Figure 5 for the molecular ar-
rangement of the calculated dimers.
excited states of the dimmers; these properties arise from
the coupling of the strongest monomer electronic transi-
tions. The calculated results suggest that the sign of the CD
intensity of complex I (+/ꢀ from the longer wavelength
side) results from molecular pair B–C rather than molecular
pair A–B, and the sign of the CD intensity of complex II
(ꢀ/+ from the longer wavelength side) results from molecu-
lar pairs A–B and A–D rather than B–C. It should also be
noted that the electronic transition of the monomer mole-
cule in each crystal has significant rotational strength be-
ꢀ
cause of the twisted molecular conformation around the C
COO bonds. Thus, the experimentally observed CD intensi-
ties are caused by this monomer distortion as well as by the
coupling of monomer electronic transitions.
Next, the solid-state CPL spectrum of complex II was
measured using KBr pellets and compared to that of com-
plex I. The solid-state CPL and fluorescence spectra of com-
plexes I[3] and II are shown in Figure 6. The fluorescence
spectrum of complex II, measured using KBr pellets is simi-
lar to that of complex II obtained without using KBr matri-
ces. This result shows that the KBr matrix does not play any
role in the measurement of spectra. A positive CPL spec-
trum was obtained for complex II. The circular anisotropy
Figure 6. Solid-state CPL and fluorescence spectra of complexes a) I and
b) II (KBr pellets).
factor, gem =2 (ILꢀIR)/
ACHTUGNRTNE(NUGN IL+IR), of complex II is approximate-
ly +4.8ꢁ10ꢀ4. As expected, a comparison of the CPL prop-
erty of chiral complex I with that of chiral complex II indi-
cated that the sign of the CPL spectra changes from nega-
tive (ꢀ) for I to positive (+) for II. To the best of our
knowledge, this is the first time that the sign of solid-state
CD and CPL in a chiral supramolecular organic fluorophore
has been controlled by changing the type of the arylethynyl
unit in the achiral 4-(2-arylethynyl)-benzoic acid component
molecule.
Conclusions
A chiral supramolecular organic fluorophore was successful-
ly synthesized by using achiral fluorescent 4-[2-(4-fluorophe-
nyl)ethynyl]-benzoic acid, or 4-[2-(4-bromophenyl)ethynyl]-
benzoic acid, and chiral (R)-(+)-1-phenylethylamine. By
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Chem. Asian J. 2011, 6, 1092 – 1098

Solid-State Chiral Optical Properties of a Supramolecular Organic Fluorophore
Measurement of Solid-State CD and Absorption Spectra
changing the arylethynyl unit in achiral 4-(2-arylethynyl)-
benzoic acid from 4-methylbenzene to 4-fluorobenzene, the
packing structure of the arylethynyl unit changed from a
planar structure for I to an intersection structure for II. As a
result, the signs of the solid-state CD and CPL spectra of
these supramolecular fluorophores were reversed despite
using the same chiral-amine component molecule. These re-
sults indicate that the solid-state chiral optical properties of
4-(2-arylethynyl)-benzoic acid/amine supramolecular organic
fluorophore can be controlled by changing the type of the
arylethynyl unit in the achiral 4-(2-arylethynyl)-benzoic acid
component molecule (that is, by changing the packing struc-
ture of the arylethynyl unit) instead of changing the chirality
of the chiral amine component molecule in the solid state.
Supramolecular organic fluorophores offering these func-
tionalities are expected to be useful in the development of
novel solid-state chiral supramolecular fluorophores.
The CD and absorption spectra were measured using a Jasco J-800KCM
spectrophotometer. The solid-state samples were prepared according to
the standard procedure for obtaining glassy KBr matrices.[11]
X-ray Crystallographic Study of Crystal II
X-ray diffraction data for single crystals were collected using a BRUKER
APEX. The crystal structures were solved by the direct method[12] and re-
fined by full-matrix least-squares using SHELXL97.[12] The diagrams
were prepared using PLATON.[13] Absorption corrections were per-
formed using SADABS.[14] Nonhydrogen atoms were refined with aniso-
tropic displacement parameters, and hydrogen atoms were included in
the models in their calculated positions in the riding model approxima-
tion. Crystallographic data for II: C23H20F1N1O2, M=361.40, space group
3
P212121, a=6.0758(3), b=7.1227(4), c=42.735(2) ꢂ, V=1849.39(17) ꢂ
1cald =1.298 gcmꢀ1ꢀ3, z=4, m
sured, 4198 unique, final R(F2)=0.0377 using 4020 reflections with I>
2.0 s(I), R(all data)=0.0397, T=115(2) K. CCDC 769653 (II) and 769654
,
AHCTUNGTRENNUNG
(MoKa)=0.089 mmꢀ1, 11408 reflections mea-
AHCTUNGTRENNUNG
(III) contains the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge Crystal-
lographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
X-ray Crystallographic Study of Crystal III
Experimental Section
Crystallographic data for III: C23H20Br1N1O2, M=386.28, space group
P21, a=7.1753(5), b=5.9312(4), c=23.1522(15) ꢂ, b=97.5860(10)8, V=
General Methods
ACTHNUTRGNEUNG
976.69(11) ꢂ 3, 1cald =1.313 gcmꢀ1ꢀ3, z=2, m(MoKa)=2.115 mmꢀ1, 8501 re-
Component molecule (R)-1 was purchased from Tokyo Kasei Kogyo Co.
Crystallization solvent was purchased from Wako Pure Chemical Indus-
try. This solvent was used directly as obtained commercially.
flections measured, 4249 unique, final R(F2)=0.0298 using 3972 reflec-
tions with I>2.0 s(I), R(all data)=0.0320, T=115(2) K.
AHCTUNGTRENNUNG
Measurement of the Solid-State CPL Spectrum
Synthesis of Compounds 3 and 4
The CPL spectrum was measured using a Jasco CPL-200 spectrophotom-
eter. The excited wavelength is 350 nm. The solid-state samples were pre-
pared according to the standard procedure for obtaining glassy KBr ma-
trices. The power of an incident beam of the CPL spectrometer is 8.0
mW/0.04 cm2 at the installation position of sample. The CPL spectrum is
approached by Simple Moving Average (SMA).
Component molecules 3 and 4 were prepared by a typical Sonogashira
electronic cross-coupling reaction.[6] Component molecule 3: 1H NMR
(300 MHz, CD3COCD3): d=8.07 (d, J=8.1 Hz, 2H), 7.68 (d, J=8.1 Hz,
2H), 7.66 (d, J=8.7 Hz, 2H), 7.24 ppm (d, J=8.7 Hz, 2H). HRMS (EI):
m/z [M]+ Calcd for C15H9FO2: 240.0587; found: 240.0651. Component
molecule 4: 1H NMR (300 MHz, CD3COCD3): d=8.08 (d, J=8.4 Hz,
2H), 7.69 (d, J=10.2 Hz, 2H), 7.65 (d, J=8.4 Hz, 2H), 7.55 ppm (d, J=
10.2 Hz, 2H). HRMS (EI): m/z [M]+ Calcd for C15H9BrO2: 299.9786;
found: 299.9932.
Acknowledgements
Formation of a Complex by Crystallization from Ethanol
(R)-1 (11 mg, 0.10 mmol) and
3 (19 mg, 0.08 mmol) or 4 (24 mg,
This study was supported by a Grant-in-Aid for Scientific Research (No.
22750133) from the Ministry of Education, Culture, Sports, Science and
Technology, Japan, and MST.
0.08 mmol) were dissolved in EtOH (3 mL) and left to stand at room
temperature. After a week, a large number of crystals of II (14 mg) were
obtained, composed of (R)-1 and 3 (or III (16 mg), composed of (R)-1
and 4). The weight reported is the total yield of the crystals obtained in a
single batch.
[1] a) J. Shinar, Organic Light-Emitting Devices, Springer, New York,
2004; b) K. Mꢄllen, U. Scherf, Organic Light-Emitting Devices,
Wiley-VCH, Weinheim, 2006; c) C. Jeanne, R. Regis, Dalton Trans.
2008, 6865–6876; d) S. Kappaun, C. Slugovc, J. M. Emil, Int. J. Mol.
Sci. 2008, 9, 1527–1547; e) K. Milan, O. Franc, Acc. Chem. Res.
2009, 42, 235–248; f) W-Y. Wong, C-L. Ho, J. Mater. Chem. 2009,
19, 4457–4482; g) K-L. Chan, P. Sonar, A. Sellinge, J. Mater. Chem.
2009, 19, 9103–9120; h) F. Laquai, Y-S. Park, J-J. Kim, T. Basche,
Macromol. Rapid Commun. 2009, 30, 1203–1231; i) C. Wang, J.
Zhang, K. Ryu, A. Badmaev, L. G. D. Arco, C. Zhou, Nano. Lett.
2009, 9, 4285–4291; j) M-K. Wei, C-W. Lin, C-C. Yang, Y-W. Kiang,
J-H. Lee, H-Y. Lin, Int. J. Mol. Sci. 2010, 11, 1527–1545 and the ref-
erences therein.
[2] a) Y. Mizobe, N. Tohnai, M. Miyata, Y. Hasegawa, Chem. Commun.
2005, 1839–1841; b) Y. Mizobe, H. Ito, I. Hisaki, M. Miyata, Y. Ha-
segawa, N. Tohnai, Chem. Commun. 2006, 2126–2128; c) S. Oshita,
A. Matsumoto, Langmuir 2006, 22, 1943–1945; d) Y. Mizobe, M.
Miyata, I. Hisaki, Y. Hasegawa, N. Tohnai, Org Lett. 2006, 8, 4295–
4298; e) Y. Imai, K. Kawaguchi, T. Harada, T. Sato, M. Ishikawa, M.
Fujiki, R. Kuroda, Y. Matsubara, Tetrahedron Lett. 2007, 48, 2927–
2930; f) Y. Imai, K. Murata, K. Kawaguchi, T. Sato, R. Kuroda, Y.
Theoretical Calculations
The HOMO–LUMO band gaps were calculated using hybrid density
functional theory (B3LYP functional[7]) with the cc-pVDZ basis set.[8]
The excitation energies and rotational strengths of molecules and molec-
ular pairs were calculated by the Zernerꢃs intermediate neglect of differ-
ential overlap (ZINDO) method.[9] These quantum chemical calculations
were carried out using the Gaussian 03 program.[10]
Measurement of Solid-State Fluorescence Spectra
Solid-state fluorescence and the absolute photo-luminescence quantum
yield were measured by Absolute PL Quantum Yield Measurement
System (C9920-02, HAMAMATSU PHOTONICS K. K.) under an air at-
mosphere at room temperature. The excited wavelength is 332, 355, and
365 nm for complexes I, II, and III, respectively.
Chem. Asian J. 2011, 6, 1092 – 1098
ꢀ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemasianj.org
1097

Y. Matsubara, Y. Imai et al.
FULL PAPERS
Matsubara, Org Lett. 2007, 9, 3457–3460; g) Y. Mizobe, T. Hinoue,
M. Miyata, I. Hisaki, Y. Hasegawa, N. Tohnai, Bull. Chem. Soc. Jpn.
2007, 80, 1162–1172; h) Y. Imai, K. Murata, K. Kawaguchi, T. Sato,
N. Tajima, R. Kuroda, Y. Matsubara, Chem. Asian J. 2008, 3, 625–
629; i) Y. Imai, K. Nagasaki, K. Murata, K. Kawaguchi, T. Harada,
Y. Nakano, T. Sato, M. Fujiki, R. Kuroda, Y. Matsubara, CrystEng-
Comm 2008, 10, 951–953; j) Y. Imai, K. Kamon, K. Murata, T.
Harada, Y. Nakano, T. Sato, M. Fujiki, R. Kuroda, Y. Matsubara,
Org. Biomol. Chem. 2008, 6, 3471–3475; k) Y. Ooyama, K. Yoshida,
Eur. J. Org. Chem. 2008, 2564–2570; l) J. Luo, T. Lei, L. Wang, Y.
Ma, Y. Cao, J. Wang, J. Pei, J. Am. Chem. Soc. 2009, 131, 2076–
2077; m) N. Shiota, T. Kinuta, T. Sato, N. Tajima, R. Kuroda, Y. Mat-
subara, Y. Imai, Cryst. Growth Des. 2010, 10, 1341–1345.
[9] a) J. E. Ridley, M. C. Zerner, Theor. Chim. Acta 1973, 32, 111–134;
b) J. E. Ridley, M. C. Zerner, Theor. Chim. Acta 1976, 42, 223–236;
c) M. C. Zerner, G. H. Lowe, R. F. Kirchner, U. T. Mueller-Westerh-
off, J. Am. Chem. Soc. 1980, 102, 589–599.
[10] Gaussian 03, RevisionE.01, M. J. Frisch, G. W. Trucks, H. B. Schle-
gel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgom-
ery, Jr., T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S.
Iyengar, 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-
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.
[3] T. Kinuta, K. Kamon, T. Harada, Y. Nakano, N. Tajima, T. Sato, M.
Fujiki, R. Kuroda, Y. Matsubara, Y. Imai, Eur. J. Org. Chem. 2009,
5760–5764.
[4] a) B. Valeur, Molecular Fluorescence, Wiley-VCH, Weinheim, 2005;
b) H. Langhals, T. Potrawa, H. Nçth, G. Linti, Angew. Chem. 1989,
101, 497–499; Angew. Chem. Int. Ed. Engl. 1989, 28, 478–480; c) H.
Langhals, R. Ismael, O. Yꢄrꢄk, Tetrahedron 2000, 56, 5435–5441;
d) K. Yoshida, Y. Ooyama, H. Miyazaki, S. Watanabe, J. Chem. Soc.
Perkin Trans. 2 2002, 700–707; e) H.-C. Yeh, W.-C. Wu, Y.-S. Wen,
D.-C. Dai, J.-K. Wang, C.-T. Chen, J. Org. Chem. 2004, 69, 6455–
6462; f) Y. Ooyama, T. Okamoto, T. Yamaguchi, T. Suzuki, A. Haya-
shi, K. Yoshida, Chem. Eur. J. 2006, 12, 7827–7838; g) Y. Ooyama,
K. Yoshida, Eur. J. Org. Chem. 2008, 2564–2570.
[11] R. Kuroda, Y. Saito, Bull. Chem. Soc. Jpn. 1976, 49, 433–436.
[12] G. M. Sheldrick, SHELXL97, Acta Crystallogr. Sect. A 2008, 64,
112–122.
[13] A. L. Spek, PLATON,
A Multipurpose Crystallographic Tool,
Utrecht University, Utrecht, Netherlands; 2010.
[14] G. M. Sheldrick, SADABS, Program for Empirical Absorption Cor-
rection of Area Detector Data, University of Gçttingen, Germany,
1996.
[5] Determined by PLATON geometry calculation.
[6] C. Rafel, N. Carmen, Chem. Rev. 2007, 107, 874–922.
[7] A. D. Becke, J. Chem. Phys. 1993, 98, 5648–5652.
[8] a) T. H. Dunning, Jr., J. Chem. Phys. 1989, 90, 1007–1023; b) D. E.
Woon, T. H. Dunning Jr, J. Chem. Phys. 1993, 98, 1358–1371.
Received: October 26, 2010
Published online: January 24, 2011
1098
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Chem. Asian J. 2011, 6, 1092 – 1098