Effects of ortho-phenyl substitution on molecular arrangements of octadehydrodibenzo[12]annulene

Article abstract of DOI:10.1246/bcsj.20130279

To modulate assembly manners of octadehydrodibenzo[12]annulene ([12]DBA) core in solid state, we first synthesized ortho-phenyl-substituted derivative 2 and investigated the effects of the substituents on the molecular stacking manner of the [12]DBA core. [12]DBA 2 yielded four types of crystals, which differ from that of the parent compound: Namely, the guest-free crystal possessing an offset stacking manner (I-GF), the solvate with a edge-to-face arrangement (II), the solvates with zigzag π-stacked arrangements (III and III'), and the solvate with 1D π-stacked columnar arrangements (IV). In the crystals, the phenyl groups contribute to limiting the stacking geometry of the [12]DBA cores and to forming void spaces accommodating various guest species, allowing versatile molecular assembly manners hitherto known for [12]DBA derivatives. We revealed that the crystals showed structure dependent fluorescence and charge carrier behaviors.

Full text of DOI:10.1246/bcsj.20130279

© 2013 The Chemical Society of Japan
Bull. Chem. Soc. Jpn. Vol. 87, No. 2, 323-333 (2014)
323
Effects of ortho-Phenyl Substitution on Molecular
Arrangements of Octadehydrodibenzo[12]annulene
Ichiro Hisaki,*1 Noriko Manabe,1 Keisuke Osaka,1 Akinori Saeki,2
Shu Seki,2 Norimitsu Tohnai,1 and Mikiji Miyata*1
1Department of Material and Life Science, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871
2Department of Applied Chemistry, Graduate School of Engineering, Osaka University,
2-1 Yamadaoka, Suita, Osaka 565-0871
Received October 9, 2013; E-mail: hisaki@mls.eng.osaka-u.ac.jp
To modulate assembly manners of octadehydrodibenzo[12]annulene ([12]DBA) core in solid state, we first syn-
thesized ortho-phenyl-substituted derivative 2 and investigated the effects of the substituents on the molecular stacking
manner of the [12]DBA core. [12]DBA 2 yielded four types of crystals, which differ from that of the parent compound:
Namely, the guest-free crystal possessing an offset stacking manner (I-GF), the solvate with a edge-to-face arrangement
(II), the solvates with zigzag π-stacked arrangements (III and III¤), and the solvate with 1D π-stacked columnar
arrangements (IV). In the crystals, the phenyl groups contribute to limiting the stacking geometry of the [12]DBA cores
and to forming void spaces accommodating various guest species, allowing versatile molecular assembly manners
hitherto known for [12]DBA derivatives. We revealed that the crystals showed structure dependent fluorescence and
charge carrier behaviors.
It is a critical issue for developing organic and supra-
molecular electronic materials to regulate stacking manner of
π-counjugated molecules.1 Peripheric aryl substitution of π-
conjugated molecules is one effective way to modulate and
control assembly of the molecules, because the substituents can
force the π-conjugated cores to be packed into certain specific
Scheme 1. [12]DBA
derivative 2.
1 and its ortho-phenyl-substituted
structures which are not achieved by the parent compounds. For
example, tetracene crystallizes in herringbone fashion through
CH-π interactions,2 while rubrene (5,6,11,12-tetraphenyltetra-
cene) crystallizes into π-stacked and herringbone structure,3
in which good π-overlap with interplanar distance of 3.7 ¡ is
responsible for high mobility.4 Nuckolls and co-workers also
investigated the assembly in the crystalline state of a series
of pentacenes that are substituted along their long edges with
one to six aromatic rings.5 More progressively, Okamoto,
Matsuo, and co-workers achieved face-to-face π-stacking
structures of phenyl- and perfluorophenyl-substituted tetracene
to enhance charge carrier properties, where phenyl-perfluoro-
phenyl stacking and C-H£F interaction effectively worked
between neighboring molecules.6 Furthermore, Jin, Fukushima,
Aida, and co-workers revealed that two phenyl groups attached
to one side of the hexabenzocoronene unit are essential for
formation of exotic graphene tubes composed of amphiphilic
hexabenzocoronene derivatives.7
the guest molecules are accommodated in the void spaces
composed of the aryl groups.8 We also reported aryl-substituted
hexadehydrotribenzo[12]annulene derivatives formed crystal-
line supramolecular architectures possessing both 1D π-stack-
ing columns and inclusion channels (1D-πSIC structure)
accommodative aryl guest species.9
In this study, we planned to investigate aryl substitution
effect on molecular arrangements of octadehydrodibenzo[12]-
annulene ([12]DBA) (Scheme 1).10 The parent compound 1
was first synthesized by Eglinton and co-workers.11 After that,
a number of its derivatives were reported for motifs of carbon-
rich materials,12 for a platform of optically and electronically
functional systems conjugated with phthalocyanine,13 Ru(II)-
coordinated dipyridophenazine,14 and dimethoxynaphthalene,15
for a building block of supramolecular architectures such as
crystalline charge-transfer complexes,16 gels,17 supramolecular
nanofibers,18 and 2D-networked assemblies on a surface,19 and
for a potential monomer of topochemical polymerization in the
solid state.16,19,20 However, the [12]DBA derivative substitu-
ted by four phenyl groups at the ortho-positions of butadiyne
moieties has not been known although the trimethylsilyl-sub-
stituted one was reported by Kira and co-workers.21 Contrary to
the parent [12]DBA 1 which assembles into only one inherent
Rigid, sterically-hindered aryl substituents can also provide
an inclusion space capable of accommodating guest species,
allowing lattice host-guest systems. In such systems, structures
of the host framework often vary depending on the guest
species. For example, Moorthy and co-workers demonstrated
that tetraarylpyrene is capable of forming various solvates
and cocrystals with different molecular arrangements, in which
Published on the web November 29, 2013; doi:10.1246/bcsj.20130279

324
(a)
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
Molecular Arrangements of Octadehydrodibenzo[12]annulene
yields,23 the present reaction resulted in moderate yield.
Reaction of 4 with trimethylsilylacetylene in the presence
of Pd(0) and ZnCl2 at 100 °C gave diethynyl derivative 5 in
67% yield.24 Desilylation of 5, followed by Cu(II)-mediated
oxidation cyclization gave dimer 2 together with trimer 6 in
51% and 28% yields, respectively.
Solutions of 2 dissolved in various organic solvents were
evaporated slowly to give crystals with and without included
solvent molecules. Their crystal data are listed in Table 1. The
obtained twelve crystals can be classified into the following
four forms according to [12]DBA’s frameworks; I-GF: a guest-
free crystal with an offset stacking manner, II(solv.): a solvate
with an edge-to-face arrangement, III(solv.) and III¤(solv.):
solvates with zigzag π-stacked arrangements, and IV(solv.):
a solvate with 1D π-stacked columnar arrangements, where
included solvents are shown in the parenthesis. The detailed
structures of the forms are described as follows.
(b)
Conformation of 2 in the Crystals.
Regarding the
conformation of the four phenyl groups, the crystals involve
in total three conformers as shown in Figure 2: Conformers
with (A) four phenyl groups twist into the same direction, (B)
two phenyl groups bound to the same side of the long edge of
[12]DBA core twist into the same direction, while the other two
twist into the opposite direction, and (C) two phenyl groups
bonding to the same phenylene ring twist in the same direction.
Such various conformations of the phenyl groups allows 2
to access versatile packing arrangements. Table 2 lists the
twisted angles of the phenyl groups of the conformers. Because
of packing force, the observed angles become slightly smaller
than the calculated value (46.7°) for D2-symmetric conformer
optimized at the B3LYP/6-31G* level. The smallest averaged
angle is observed in I-GF.
Crystal Structure of I-GF. [12]DBA 2 itself is packed with
an offset stacking manner to yield guest-free (GF) crystal (I-GF)
belonging to the space group P21/n (Figure 3a). The crystals
were obtained by slow evaporation of chloroform, ethyl acetate,
or mesitylene solution, although formation occurred acciden-
tally and depended on the crystallization batches. It is surprising
for us that 2 experiences the unexpected offset stacking, instead
of slipped stacking along the long molecular axis as shown in
Figure 1a, even though the [12]DBA core carries sterically-
hindered phenyl groups. The substituted phenyl groups, which
are staggered by 38.2-48.1° from the [12]DBA plane, are
located on the adjacent [12]DBA planes (dihedral angles of the
phenyl and the neighboring [12]DBA planes: 13.2°) to prevent
the [12]DBA moieties from stacking with each other. The
substituted phenyl groups are also contacted intermolecularly
in twofold helical herringbone fashion (dihedral angle of the
adjacent phenyl groups: 57.8°) as shown in Figure 3b.
Figure 1. Assembly of (a) parent π-system and (b) aryl-
substituted π-system. The former yields only an inherent
assembly structure, while the latter can provide versatile,
unusual supramolecular architectures via (1) aggregation
in a geometrically restricted manner and (2) inclusion of
guest molecules, which would give lattice frameworks
depending on the guest species.
form (Figure 1a), we expected that ortho-phenyl-substituted
[12]DBA 2 could provide versatile, unusual supramolecular
architectures via (1) aggregation in a geometrically-limited
manner, such as stacking only along the long molecular axis
with good π-overlap as observed for rubrene (Figure 1b-1),
and/or (2) inclusion of guest molecules which would give
various lattice frameworks depending on the guest species
(Figure 1b-2).
Herein, we describe synthesis of the ortho-aryl-substituted
[12]DBA 2, its crystal structures with or without guest molec-
ules and structure-dependent optical and electrical properties.
The present system is the first example for the [12]DBA
derivatives to give such versatile molecular assembly manner,
implying a rational way to modulate molecular arrangements
not only of the [12]DBA but also of a wide range of π-conju-
gated molecules.
Crystal Structure of the Form II. Recrystallization from
a chloroform solution gave a solvate II(CHCl3) belonging to
the space group P21/c, concomitantly with the crystals I-GF.
Contrary to I-GF, II(CHCl3) has a phase-separated structure:
namely, the crystal has a layer composed of the [12]DBA
core and that of the substituted phenyl parts (Figure 4a). The
[12]DBA cores form a porous sheet motif through face-to-edge
(CH-π) interactions at the short edges of the [12]DBA core
(angle between [12]DBA planes: 73.8°) (Figure 4b). The void
spaces accommodate chloroform molecules with a 1:1 host/
Results and Discussion
Preparation and Crystallization of [12]DBA 2. [12]DBA
2 was synthesized according to Scheme 2. Cross-coupling
reaction of 1,2,3,4-tetrabromobenzene (3)22 with phenylboronic
acid gave 1,4-disubstituted product 4 in 39% yield. Although
Vollhardt and co-workers reported selective Sonogashira reac-
tion of 3 with acetylene derivatives at 1,4-positions in high

I. Hisaki et al.
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
325
Scheme 2. Synthetic route of [12]DBA 2.
(b)
(a)
(e)
(c)
(d)
Figure 2. Molecular conformations of 2 in crystals of (a) I-GF, (b) II(CHCl3), (c) III(DCM), and (d) IV(DCM). The signs +
and ¹ indicate the rotation direction of the substituted phenyl groups as shown in (e). The crystals II(CHCl3) and IV(DCM) contain
two crystallographically independent molecules (molecules 1 and 2). Conformer A, in which four phenyl groups twist into the same
direction. Comformer B, in which two phenyl groups bonded to the same side of the long edge of the [12]DBA core twist into the
same direction, while the other two twist into the opposite direction. Conformer C, in which two phenyl groups bonded to the same
phenylene ring twist into the same direction. The structures are drawn with thermal ellipsoids with 50% probability except for
(b) II(CHCl3), which is with 75% probability.
guest ratio. It is well known that significant dispersion force
works between chlorine atoms of the chloroform and π-conju-
gated plane.25 Therefore, such interaction is one of the factors
to give the present structure. The substituted phenyl groups
form densely-packed sheet motif as shown in Figure 4c. The
phenyl groups bonded to one [12]DBA layer, colored with

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Molecular Arrangements of Octadehydrodibenzo[12]annulene

I. Hisaki et al.
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
327
(a)
Table 2. Conformation of the Substituted Phenyl Groups
Crystal
Twisted anglesa)
Conformerb)
I-GF
38.23-48.11 (43.21)
37.45-56.55 (48.45)
44.79-46.79 (45.75)
44.15-46.57 (45.36)
42.73-46.46 (44.59)
45.65-46.23 (45.94)
44.61-45.63 (45.12)
44.28-45.27 (44.78)
44.20-46.40 (45.19)
42.05-45.98 (44.51)
41.86-45.35 (43.59)
40.87-46.77 (43.91)
C
II(CH3Cl)
III(DCM)
III(Tol)
A, Bc)
B
B
B
B
B
B
B
C, Cc)
C, Cc)
C, Cc)
III(o-Xyl)
III(m-Xyl)
III(p-Xyl)
III(Mes)
III¤(THF)
IV(DCM)
IV(AcOEt)
IV(DCE)
(b)
a) Averaged values are shown in parentheses. b) Detailed
structures of the conformers are given in Figure 2. c) Two
crystallographically independent molecules are included in the
unite cell.
(a)
(b)
(c)
Figure 4. Crystal structure of II(CHCl3). (a) Packing
diagram viewed from the b axis, (b) the [12]DBA layer,
and (c) the phenyl layer, in which the phenyl groups bound
to the [12]DBA layer (green) and those to the next DBA
layer (yellow) are densely packed in orthogonal fashion.
The guest molecule is disordered in two positions, one of
which is shown in orange.
Figure 3. Crystal structure of I-GF. (a) Packing diagrams
viewed from the b and c axes. (b) Twofold helical arrange-
ments of the substituent phenyl groups.
between the layers. Besides crystal III(DCM), 2 yields crystals
III including toluene, o-xylene, m-xylene, p-xylene, 1,3,5-
trimethylbenzene (mesitylene), and tetrahydrofuran [III(Tol),
III(o-Xyl), III(m-Xyl), III(p-Xyl), III(Mes), and III¤(THF),
respectively] as shown in Figure 6. III(DCM) includes di-
chloromethane with a 1:2 host/guest ratio, while III(Tol),
III(o-Xyl), III(m-Xyl), and III(p-Xyl) with a 1:1 host/guest
ratio. These crystals belong to the same space group P21/c
and exhibit nearly identical lattice parameters including the
a axis (14.1-14.5 ¡) which corresponds to distance between
layers. These results indicate that the void space did not strictly
recognize molecular shapes of mono- or disubstituted benzene.
Solvate of trisubstituted benzene III(Mes), which includes
mesitylene with a DBA/guest ratio of 1:2 similar with
III(DCM), belongs to the space group P21/c, while the lattice
parameters differ from the formers. Particularly the a axis is
elongated up to 18.8 ¡. The solvate of THF also has the same
zigzag layer motif with a 1:1 host/guest ratio. However, the
green, are in meshing engagement with those bonded to the
next [12]DBA layer, colored with yellow, to form the densely-
packed sheet structure. The nearly orthogonal contact of the
phenyl groups (the dihedral angle and distance between centers
of the phenyl groups are 81.8-87.1° and 4.86-5.06 ¡, respec-
tively) should contribute the stabilization of the crystal.26
Crystal Structure of the Forms III and III¤. Crystal-
lization from dichoromethane gave crystals III(DCM) and
IV(DCM) concomitantly or either of them depending on the
crystallization batches. III(DCM) belongs to the space group
P21/c. The [12]DBA molecules stack into a zigzag fashion
through π-π interaction between the fused benzene moieties
(the closest stacking distance: 3.40 ¡) as shown in Figure 5a,
and through face-to-edge (CH-π) interactions between sub-
stituted phenyl groups (dihedral angle: 74.5°) as shown in
Figure 5b. Dichloromethane molecules are accommodated
between the layers with a host/guest ratio of 1:2.
ꢀ
layers are arranged in slightly slipped manner to give P1
crystal III¤(THF). These results indicate that the zigzag layer
composed of 2 can be applied for a platform of new crystalline
host-guest systems.
Interestingly, the zigzag-stacked layer structure observed
here are revealed to be tolerant for guest species included

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The P1 crystal
Molecular Arrangements of Octadehydrodibenzo[12]annulene
ꢀ
Crystal Structure of the Form IV.
to-edge contact (the dihedral angle: 85.2-87.1°). This type of
molecular arrangement was also obtained when ethyl acetate
and dichloroethane were applied as solvents: III(AcOEt) and
III(DCE), respectively. The crystal structures are shown in
Figures S4 and S5.
IV(DCM) accommodates dichloromethane in a 1:1 host/guest
ratio. Two crystallographically independent molecules of 2 are
alternately π-stacked to give a 1D columnar motif (Figure 7a).
The DBAs in the column show slippage in the long axis direc-
tion and no significant slippage in the short axis due to steric
effect of the phenyl groups (Figure 7b), in which dichloro-
methane molecules are accommodated in void spaces of the
layer to form a densely packed layer structure similar to that in
II(CHCl3) as shown in Figure 7c. In the layer, the adjacent
phenyl groups are arranged nearly perpendicular with face-
Examination of Topochemical Polymerization in Crystals
IV. Cyclic compounds containing more than one butadiyne
(a)
(a)
(b)
(b)
(c)
Figure 7. Crystal structure of IV(DCM). (a) Packing dia-
grams viewed from the a and c axes, (b) relative orien-
tation of DBA 2 molecules in the column, (c) the layer
structure composed of the phenyl groups colored green and
guest molecules (dichloromethane) colored orange. The
guest molecule is disordered in two positions, one of which
is shown in orange.
Figure 5. Crystal structure of III(DCM). (a) Packing dia-
grams viewed from the a and c axes. (b) Arrangements of
the substituted phenyl groups. The guest molecule is disor-
dered in two positions, one of which is shown in orange.
(a)
(b)
(c)
(d)
(e)
(f)
(g)
Figure 6. Pacing diagrams of (a) III(DCM), (b) III(Tol), (c) III(o-Xyl), (d) III(m-Xyl), (e) III(p-Xyl), (f) III(Mes), and
(g) III¤(THF), in which the guest molecules are shown with the space-fill models colored orange. The guest molecule in III(DCM),
III(Tol), III(o-Xyl), III(m-Xyl), and III(p-Xyl) is disordered in two positions, one of which is shown in orange.

I. Hisaki et al.
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
329
(a)
(b)
(c)
Scheme 3. (a) Proposed ene-yne ladder polymer formed by topochemical polymerization of [12]DBA. Stacking manner of [12]DBA
with slippage both in short and long axes directions (b) and only in long axis direction (c).
Table 3. Geometric Parameters of Crystals IV(DCM),
IV(AcOEt), and IV(DCE)a)
are close to the ideal values for topochemical polymerization;
i.e., d = 4.9 ¡, ª = 45°, d1-4 = 3.4 ¡. Therefore, we examined
topochemical polymerization on the crystals IV(DCM) and
IV(AcOEt). First, to investigate heat-induced polymerization,
the crystals IV(DCM) and IV(AcOEt), as well as III(DCM) as
a reference, are subjected to differential scanning calorimetry
(DSC), showing weak endothermic peaks at 108, 103, and
90 °C, respectively, and significant exothermic peaks at 294,
300, and 289 °C, respectively (Figure 8a). Thermal gravimetric
(TG) analysis of the crystals indicates that the former peaks
correspond to structural transformation due to guest desorption
(Figure 8b). Furthermore, powder X-ray diffraction (PXRD)
patterns of the crystals after the transformation agreed with that
of I-GF (Figure S6). These results indicate that the crystals
released the guest molecules upon heating, to transform into the
guest-free form unsuitable for topochemical polymerization.
The exothermic peaks at around 300 °C are probably attri-
buted to thermal decomposition of the compound. Indeed, the
resultant black materials show no PXRD signals and were
insoluble in common organic solvents, preventing solution
NMR analysis. Next, the polymerization at room temperature
Ideal
IV(DCM)
IV(AcOEt)
IV(DCE)
db)/¡
ªc)/°
d1-4d)/¡
4.9
45
3.4
4.84-4.99
49.4-48.9
3.76-3.74
4.79-4.95
48.0-47.6
3.62-3.64
4.86-4.99
51.4-52.1
3.91-3.92
a) The respective value of parameters have ranges, because the
crystals involve two crystallographically independent mole-
cules. b) d: Stacking distance. c) ª: slipping angle. d) d1-4: C1-4
distance.
in the cycle are intensively investigated because topochem-
ical polymerization27-29 occurring in their one-dimensionally
stacked architectures can provide ladder- or tube-type ene-yne
polymeric materials. The topochemical polymerization of a
cyclic system is first achieved by Vollhardt, Youngs, and co-
workers for crystals of octadehydrotribenzo[14]annulene in
1995.30 Subsequently, construction of 1D-stacked assemblies
and their topochemical polymerization were reported by
Shimizu’s,29a Lauher’s,29d and Morin’s29e groups. [12]DBA is
also a candidate for the monomer of the reaction (Scheme 3a).
However, in spite of great efforts, there is no report of topo-
chemical polymerization of [12]DBA derivatives. We care-
fully evaluated crystal structures of the [12]DBA derivatives
reported, and consequently found in fact that the all [12]DBAs
slipped in the shorter axis direction of the molecules as well as
in the longer axis direction (Scheme 3b, also see Figure S1),
except for phenanthrene annelated [12]DBA reported quite
recently by Nakamura and co-workers.18 The slippage in the
short axis causes molecular assemblies unfavorable for top-
ochemical polymerization, judging from the optimized struc-
ture of the expected ene-yne polymer (Figure S2). On the
other hand, the IV crystals obtained in the present study
possess desired 1D π-stacked columnar architecture with no
slippage in the short axis direction but in longer axis direction
(Scheme 3c).
¹1
was attempted by γ-ray irradiation (81.1 Gy h for 24 h) or
UV (Xe-ramp 300 W for 48 h) to the crystals IV(DCM) and
IV(AcOEt). Surprisingly, however, the crystals showed no
reaction and their structures remained under the reaction
conditions. This significant stability implies that the reaction
would require more precise and strict geometric conditions
and/or that the phenyl groups densely-packed in the edge-to-
face fashion would not allow even subtle structural changes
caused by topochemical polymerization.
Structure-Dependent Optical and Electrical Properties of
the Crystals. Optical and electrical properties of the obtained
crystals were investigated because a π-stacked arrangement of
the [12]DBA core must strongly affect on them. Figure 9 and
Table 4 show optical data of I-GF, III(DCM), and IV(DCM),
as well as those of 2 in solution.31 The fluorescence spectrum of
crystal I-GF has an obvious vibrational structure with -em
=
max
Table 3 shows the geometric parameters of IV crystals,
particularly IV(AcOEt) and IV(DCM), whose d, ª, and d1-4
values are ranged in 4.79-4.99 ¡, 47.6-52.1°, and 3.62-3.92 ¡,
respectively, where d, ª, and d1-4 indicate stacking distance,
slipping angle, and intermolecular distance between C1 and
C4 atoms of butadyine moieties, respectively. These values
571 nm [ºF = 0.3%, ¸ = 1.5 ns (97%), and 9.8 ns (3%)], where
em
-
max, ºF, and ¸ denote wavelength at fluorescence maximum,
fluorescence quantum yield, and fluorescence lifetime, respec-
tively, similar to those observed in a solution state. Crystal
III(DCM) also has an unambiguous vibrational spectrum with
em
-
max = 564 nm [ºF = 1.3%, ¸ = 1.8 ns (22%), and 2.7 ns

330
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
(a)
Molecular Arrangements of Octadehydrodibenzo[12]annulene
Table 4. Optical Properties of 2 in Solution and Crystals
I-GF, III(DCM), and IV(DCM)
em
ex
-
-
¸
/ns
max
max
ºF
/nm
/nm
2a)
I-GF
III(DCM)
IV(DCM)
557
571
564
592
248
469
468
468
0.012b) 1.5 (96%), 4.2 (4%)
0.003
0.013
0.005
1.5 (97%), 9.8 (3%)
1.8 (22%), 2.7 (78%)
2.1 (60%), 3.2 (40%)
a) Measured in chloroform solution. b) Determined based on
that of rhodamine G6 with -ex = 375 nm.
(78%)]. Crystals IV(DCM), on the other hand, show weak,
structureless spectra with -emmax = 591 nm [ºF = 0.5%, ¸ =
2.1 ns (60%), and 3.2 ns (40%)], indicating that the molecular
arrangements of the crystals IV provides a more stable excited
state compared with the crystals I-GF and III, probably due to
generation of species such as excited oligomers.
(b)
Charge carrier behavior of IV(DCM) was also investigated
by flash-photolysis time-resolved microwave conductivity (FP-
TRMC) measurement,32 revealing that the crystal IV(DCM)
¹5
exhibited moderate photoconductivity (º-® = 2.9 © 10
cm2 V¹1 s¹1) along the crystallographic a axis, which corre-
sponds to the π-stacked direction of the [12]DBA. The value is
2.7 times larger than those in the orthogonal axis (º-® =
1.1 © 10¹5 cm2 V¹1 s¹1). The anisotropy of the conductivity
is smaller than the columnar assembly of tribenzohexade-
hydro[12]annulene derivatives reported previously by our
group,33 indicating that the phenyl substituents staggered from
the [12]DBA plane provide a pathway to charge carriers in the
orthogonal directions.
Figure 8. Thermal analyses of the crystals IV(DCM) and
IV(AcOEt), as well as III(DCM). (a) DSC curves, (b) TG
curves.
(a)
Conclusion
In this study, we synthesized an ortho-phenyl-substituted
derivative of octadehydrodibenzo[12]annulene ([12]DBA 2)
and investigated the effects of the aryl substituents on molec-
ular stacking manner of the [12]DBA core. [12]DBA 2 yielded
four types of crystalline lattices including a hitherto unknown
form: the guest-free crystal possessing an offset stacking
manner (I-GF), the solvate with an edge-to-face arrangement
(II), the solvates with zigzag π-stacked arrangements of
[12]DBA (III and III¤), and the solvate with 1D π-stacked
columnar arrangements of [12]DBA (IV). The substituted
phenyl groups provided void spaces, in which various guest
species are accommodated. Particularly, the zigzag π-stacked
motif formed in III and III¤ is tolerant of guest species
included between the layers, and therefore, can be a platform
for a new crystalline host-guest system. Moreover, aggregation
of [12]DBA cores is restricted by the phenyl groups, giving
an unusual assembly in the crystal IV, that is, 1D π-stacked
columnar architecture with no slippage in the short axis direc-
tion but in the longer axis direction. The structure has nearly
ideal geometry for the topochemical polymerization. However,
the anticipated polymeric material has not been obtained yet.
The crystal with the 1D π-stacked motif exhibits broaden, red-
shifted fluorescence spectral profiles and anisotropic charge
carrier behaviors ascribable to strong interaction between the
π-orbitals of the adjacent [12]DBA cores. Finally, we conclude
that ortho-substitution with phenyl groups, which provided
(b)
Figure 9. Structure-dependent optical and electrical proper-
ties. (a) Fluorescence spectra of I-GF, III(DCM), and
IV(DCM), as well as 2 in chloroform solution. (b) Aniso-
tropic charge carrier behavior of IV(DCM) in π stacked
and orthogonal direction (red and blue lines, respectively).

I. Hisaki et al.
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
331
(1) aggregation with geometrically-restricted, unusual manner
different from that of the parent [12]DBA and (2) inclusion of
guest molecules which bring about formation of lattice frame-
works depending on the guest species, can be a rational way to
modulate molecular arrangements of the [12]DBA.
resolved microwave conductivity (TRMC) measurements, the
microwave frequency and power were set at ca. 9.1 GHz and
3 mW, respectively, so that the motion of the charge carriers
was not disturbed by the low electric field of the microwaves.
The TRMC signal picked up by a diode (rise time <1 ns) is
monitored with a digital oscilloscope. All the above experi-
ments were carried out at room temperature. The photoconduc-
tivity is given by the equation º-® = (1/eAI0Flight)(¦Pr/Pr),
where º, -®, e, A, I0, Flight, Pr, and ¦Pr denote photocarrier
generation yield, the sum of the charge carrier mobilities, the
unit charge of a single electron, the sensitivity factor (S¹1 cm),
the incident photon density of an excitation laser (photon
cm¹2), the filling factor (cm¹1), and the reflected microwave
power and its change, respectively.
Experimental
General. 1H and 13C spectra were measured with a JEOL
1
spectrometer (270 or 400 MHz for H and 67.5, 100, or 150
MHz for 13C). Mass spectra data were obtained with a JEOL
JMS-700 instrument or autoflex III Bruker. UV-vis spectra in
solution were measured using a JASCO V-550 spectrometer.
Emission spectra in solution were measured using a JASCO
FP-6500 spectrofluorometer. The fluorescence decay times
and lifetimes were obtained using HORIBA FluoroCube and
the software (Data Station v.2.4 and DAS 6) supplied in the
apparatus.
Synthesis of Terphenyl Derivative 4.
A mixture of
1,2,3,4-tetrabromobenzene (3)22 (2.00 g, 5.08 mmol), phenyl-
boronic acid (1.55 g, 2.7 mmol), [Pd(PPh3)4] (0.298 g, 0.254
mmol), Na2CO3 (1.09 g, 10.1 mmol) in degassed 1,4-dioxane
(15 mL), toluene (15 mL), and water (15 mL) was stirred for
24 h under reflux. The reaction mixture was extracted with
CH2Cl2, washed with brine, and dried over anhydrous MgSO4.
The product was purified by column chromatography (silica
gel, hexane/CH2Cl2 = 4/1), followed by rinsing with hexane
to give 4 (759 mg, 39%) as a while solid.
Single-Crystal X-ray Analysis. For crystals I-GF, III(Tol),
III(Mes), III¤(THF), and IV(DCM), diffraction data were
collected on a Rigaku R-AXIS RAPID diffractometer with a
2D area detector using graphite-monochromatized Cu Kα radia-
tion (- = 1.54187 ¡). The cell refinements were performed
with software equipped in a Rigaku R-AXIS RAPID system.
For crystals II(CHCl3), III(DCM), III(o-Xyl), III(p-Xyl)
III(m-Xyl), IV(AcOEt), IV(DCE), and 6, diffraction data were
collected on a CCD (Q315, ADSC) with the synchrotron radia-
tion (- = 0.7000 or 0.8000 ¡) monochromated by a fixed exit
Si(111) double crystal. The cell refinements were performed
with HKL2000 software.34 Direct methods (SIR-200435 or
SIR200836) were used for the structure solution of the crystals.
All calculations were performed with the observed reflections
[I > 2·(I)] with the program CrystalStructure crystallographic
software packages,37 except for refinement, which was per-
formed using SHELXL-97.38 All non-hydrogen atoms were
refined with anisotropic displacement parameters, and hydro-
gen atoms were placed in idealized positions and refined as
rigid atoms with the relative isotropic displacement parameters.
Crystallographic data have been deposited with Cambridge
Crystallographic Data Centre: Deposition numbers CCDC-
940772 for I-GF, CCDC-964560 for II(CHCl3), CCDC-
940773 for III(DCM), CCDC-964566 for III(Tol), CCDC-
964563 for III(o-Xyl), CCDC-964562 for III(m-Xyl), CCDC-
964564 for III(p-Xyl), CCDC-964561 for III(Mes), CCDC-
964565 for III¤(THF), CCDC-940774 for IV(DCM), CCDC-
940775 for IV(AcOEt), CCDC-940776 for IV(DCE), and
CCDC-940777 for compound 6. Copies of the data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/conts/
retrieving.html (or from the Cambridge Crystallographic Data
Centre, 12, Union Road, Cambridge, CB2 1EZ, U.K.; Fax:
+44 1223 336033; e-mail: deposit@ccdc.cam.ac.uk).
4: mp: 121 °C. 1H NMR (270 MHz, CDCl3): ¤ 7.48-7.39
(m, 10H), 7.29 (s, 2H). 13C NMR (67.5 MHz, CDCL3): ¤ 144.5,
142.3, 129.7, 129.6, 128.4, 128.2, 127.0. HR-MS(FAB): calcd
for C18H12Br2 [M]+ 387.9285; found 387.9280.
Synthesis of Diethynylterphenyl Derivative 5. A mixture
of 4 (2.60 g, 6.70 mmol), [Pd(PPh3)4] (778 mg, 0.674 mmol),
PPh3 (370 mg, 1.41 mmol), ZnCl2 (273 mg, 2.00 mmol), tri-
methylsilylacetylene (4.73 mL, 3.29 g, 33.5 mmol) in degassed
piperidine (30 mL) and triethylamine (30 mL) was placed in a
pressure glass tube, purged by N2 gas, and sealed. After stirred
for 17 h at 100 °C, the solvent was removed in vacuo and
the reaction mixture was extracted with CH2Cl2, washed with
brine, and dried over anhydrous MgSO4. The product was
purified by column chromatography (silica gel, CH2Cl2),
followed by rinsing with MeOH to give 5 (1.89 g, 67%) as a
white solid.
5: mp: 144 °C. 1H NMR (270 MHz, CDCl3): ¤ 7.63-7.60
(m, 4H), 7.45-7.37 (s, 8H), 0.14 (s, 18H). 13C NMR (67.5
MHz, CDCl3): ¤ 144.0, 140.4, 129.7, 129.6, 128.1, 127.9,
125.2, 103.4, 103.0, 0.06. HR-MS(FAB): calcd for C28H30Si2
[M]+ 422.1886; found 422.1889.
Synthesis of [12]DBA 2. A mixture of 5 (802 mg, 1.90
mmol) and K2CO3 (5.25 g, 38.0 mmol) in THF (40 mL) and
MeOH (40 mL) was stirred at room temperature for 2 h. The
reaction mixture was extracted with CH2Cl2, washed with
water and brine, and dried over anhydrous MgSO4. The product
was used in the following step without further purification.
To a solution of copper acetate monohydrate (8.20 g, 41.2
mmol) dissolved in pyridine (300 mL) and methanol (300 mL)
was added dropwise the above product dissolved in pyridine
(100 mL) over 1 h with stirring at 60 °C and stirred for 12 h
at this temperature. The reaction mixture was extracted with
CH2Cl2, washed with 5% HCl and brine, and dried over anhy-
drous MgSO4. The product was purified by column chroma-
tography (silica gel, CH2Cl2) and preparative HPLC (CHCl3) to
Powder Diffraction X-ray Analysis. PXRD data were
collected on a Rigaku RINT-2000 using graphite-monochrom-
atized Cu Kα radiation (- = 1.54187 ¡) at room temperature.
Flash-Photolysis Time-Resolved Microwave Conductivi-
ty (FP-TRMC) Measurement.32 Nanosecond laser pulses
from a Nd:YAG laser (third harmonic generation, THG
(355 nm) from Spectra Physics, INDI, FWHM 5-8 ns) were
used as excitation sources. The incident photon density of
the laser was set at 9.1 © 1015 photons/cm2/pulse. For time-

332
Bull. Chem. Soc. Jpn. Vol. 87, No. 2 (2014)
Molecular Arrangements of Octadehydrodibenzo[12]annulene
6
T. Okamoto, K. Nakahara, A. Saeki, S. Seki, J. H. Oh, H. B.
give dimer 2 (267 mg, 51%) as a yellow solid and trimer 6
(149 mg, 28%) as a pale yellow solid.
2: mp (dec.) 296 °C. H NMR (400 MHz, CDCl3, 25 °C): ¤
Akkerman, Z. Bao, Y. Matsuo, Chem. Mater. 2011, 23, 1646.
1
7
W. Jin, Y. Yamamoto, T. Fukushima, N. Ishii, J. Kim, K.
Kato, M. Takata, T. Aida, J. Am. Chem. Soc. 2008, 130, 9434.
a) J. N. Moorthy, P. Natarajan, P. Venugopalan, J. Org.
7.50-7.48 (m, 8H), 7.42-7.36 (m, 12H), 7.18 (s, 4H). 13C NMR
(100 MHz, CDCl3 55 °C): ¤ 141.6, 139.5, 130.3, 129.9, 128.5,
128.4, 128.2, 91.6, 86.7. HR-MS(FAB): calcd for C44H24 [M]+
552.1878; found 552.1884.
8
Chem. 2009, 74, 8566. b) J. N. Moorthy, P. Natarajan, P.
Venugopalan, Chem. Commun. 2010, 46, 3574.
9
I. Hisaki, H. Senga, H. Shigemitsu, N. Tohnai, M. Miyata,
1
6: mp (dec.) 200 °C. H NMR (400 MHz, CDCl3 25 °C): ¤
Chem.®Eur. J. 2011, 17, 14348.
7.59-7.56 (m, 12H), 7.49-7.46 (m, 12H), 7.41-7.38 (m, 12H).
13C NMR (150 MHz, pyridine-d5, 80 °C): ¤ 145.6, 139.7, 130.7,
129.6, 129.0, 128.7, 124.6, 82.3, 82.1. HR-MS(MALDI-TOF):
calcd for C66H36Na [M + Na]+ 851.2709; found 851.2685.
Crystal data for 6: C66H36, Mr = 829.01, a = 27.5291(3) ¡,
b = 20.3658(2) ¡, c = 15.8144(2) ¡, V = 8866.38(18) ¡3, T =
100 K, orthorhombic, space group Pbca, Z = 8, dcalcd = 1.242
g cm¹3, 42030 collected, 8894 unique (Rint = 0.042) reflec-
tions, the final R1 and wR2 values 0.0450 (I > 2.0·(I)) and
0.1249 (all data), respectively. CCDC-940777. Also see
Figure S3 in the Supporting Information.
10 For recent reviews of dehydrobenzoannulenes, see: a) I.
Hisaki, M. Sonoda, Y. Tobe, Eur. J. Org. Chem. 2006, 833. b) E. L.
Spitler, C. A. Johnson, II, M. M. Haley, Chem. Rev. 2006, 106,
5344.
11 O. M. Behr, G. Eglinton, R. A. Raphael, Chem. Ind. 1959,
699.
12 a) J. D. Tovar, N. Jux, T. Jarrosson, S. I. Khan, Y. Rubin,
J. Org. Chem. 1997, 62, 3432. b) M. E. Gallagher, J. E. Anthony,
Tetrahedron Lett. 2001, 42, 7533. c) J. A. Marsden, M. J.
O’Connor, M. M. Haley, Org. Lett. 2004, 6, 2385.
13 a) M. J. Cook, M. J. Heeney, Chem.®Eur. J. 2000, 6, 3958.
b) E. M. García-Frutos, F. Fernández-Lázaro, E. M. Maya, P.
Vázquez, T. Torres, J. Org. Chem. 2000, 65, 6841. c) M. J. Cook,
M. J. Heeney, Chem. Commun. 2000, 969.
14 S. Ott, R. Faust, Chem. Commun. 2004, 388.
15 T. Nishinaga, H. Nakayama, N. Nodera, K. Komatsu,
Tetrahedron Lett. 1998, 39, 7139.
16 a) U. H. F. Bunz, V. Enkelmann, Chem.®Eur. J. 1999, 5,
263. b) T. Nishinaga, N. Nodera, Y. Miyata, K. Komatsu, J. Org.
Chem. 2002, 67, 6091.
This work was supported by Grant-in-Aid for Young
Scientists (A) (No. 24685026) for Challenging Exploratory
Research (No. 24655031) from MEXT Japan. This work is
partly supported by JSPS and NSF under the JSPS-NSF Inter-
national Collaborations in Chemistry (ICC). We thank Ms. S.
Tojo at The Institute of Scientific and Industrial Reasearch
(ISIR), Osaka University for γ-ray irradiation. Crystallographic
data was partly collected using a synchrotron radiation at the
BL38B1 in the SPring-8 with approval of JASRI (proposal
Nos. 2010B1370, 2011A1341, 2011B1587, and 2013A1104).
17 I. Hisaki, H. Shigemitsu, Y. Sakamoto, Y. Hasegawa, Y.
Okajima, K. Nakano, N. Tohnai, M. Miyata, Angew. Chem., Int.
Ed. 2009, 48, 5465.
18 a) H. Shigemitsu, I. Hisaki, H. Senga, D. Yasumiya, T. S.
Thakur, A. Saeki, S. Seki, N. Tohnai, M. Miyata, Chem.®Asian
J. 2013, 8, 1372. b) S.-i. Kato, N. Takahashi, H. Tanaka, A.
Kobayashi, T. Yoshihara, S. Tobita, T. Yamanobe, H. Uehara, Y.
Nakamura, Chem.®Eur. J. 2013, 19, 12138. c) H. Shigemitsu, I.
Hisaki, E. Kometani, D. Yasumiya, Y. Sakamoto, K. Osaka, T. S.
Thakur, A. Saeki, S. Seki, F. Kimura, T. Kimura, N. Tohnai, M.
Miyata, Chem.®Eur. J. 2013, 19, 15366.
Supporting Information
Spectral data, Crystallographic data of 6, IV(AcOEt), and
IV(DCE), and theoretical calculations. This material is avail-
able free of charge on the web at http://www.csj.jp/journals/
bcsj/.
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