Synthesis and physical properties of ferrocene derivatives (XXIII): Phase transition and unique molecular structure of monosubstituted ferrocene derivatives

Article abstract of DOI:10.1080/15421400903400829

The monosubstituted ferrocene derivatives, -[4-(4-methoxyphenoxycarbonyl) phenoxy]alkoxycarbonyl ferrocene, were synthesized in order to compare the liquid crystallinity to that of disubstituted ferrocene derivatives, 1,1'-bis[-[4-(4-methoxy-phenoxycarbonyl)phenoxy]alkoxycarbonyl]ferrocene. Some of the monosubstituted ferrocene derivatives containing relatively longer flexible spacer showed the liquid crystalline phase, nematic and/or smectic phases. The crystal structure of 2-[4-(4-methoxyphenoxycarbonyl)phenoxy] ethoxycarbonyl ferrocene was determined by X-ray diffraction method using a single crystal. The molecular structure revealed a bent structure that is almost a half of "Z" shaped molecular structure of 1,1'-bis[2-[4-(4- methoxyphenoxycarbonyl)phenoxy]ethoxycarbonyl]ferrocene.

Full text of DOI:10.1080/15421400903400829

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Synthesis and Physical Properties of
Ferrocene Derivatives (XXIII) Phase
Transition and Unique Molecular
Structure of Monosubstituted Ferrocene
Derivatives
a
Naotake Nakamura a , Kazuya Hiro∗ a , Masako Nishikawa∗∗
Takashi Okabe∗∗∗ a & Kenjiro Uno a
,
a Department of Applied Chemistry, College of Science and
Engineering , Ritsumeikan University , Kusatsu, Shiga, Japan
Published online: 22 Feb 2010.
To cite this article: Naotake Nakamura , Kazuya Hiro∗ , Masako Nishikawa∗∗ , Takashi Okabe∗∗∗ &
Kenjiro Uno (2010) Synthesis and Physical Properties of Ferrocene Derivatives (XXIII) Phase Transition
and Unique Molecular Structure of Monosubstituted Ferrocene Derivatives, Molecular Crystals and
Liquid Crystals, 516:1, 122-131, DOI: 10.1080/15421400903400829
To link to this article: http://dx.doi.org/10.1080/15421400903400829
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Mol. Cryst. Liq. Cryst., Vol. 516: pp. 122–131, 2010
Copyright # Taylor & Francis Group, LLC
ISSN: 1542-1406 print=1563-5287 online
DOI: 10.1080/15421400903400829
Synthesis and Physical Properties of Ferrocene
Derivatives (XXIII): Phase Transition and Unique
Molecular Structure of Monosubstituted
Ferrocene Derivatives
NAOTAKE NAKAMURA, KAZUYA HIROꢀ,
MASAKO NISHIKAWAꢀꢀ, TAKASHI OKABEꢀꢀꢀ
AND KENJIRO UNO
,
Department of Applied Chemistry, College of Science and Engineering,
Ritsumeikan University, Kusatsu, Shiga, Japan
The monosubstituted ferrocene derivatives, x-[4-(4-methoxyphenoxycarbonyl)
phenoxy]alkoxycarbonyl ferrocene, were synthesized in order to compare the liquid
crystallinity to that of disubstituted ferrocene derivatives, 1,10-bis[x-[4-(4-methoxy-
phenoxycarbonyl)phenoxy]alkoxycarbonyl]ferrocene. Some of the monosubstituted
ferrocene derivatives containing relatively longer flexible spacer showed the liquid
crystalline phase, nematic and=or smectic phases. The crystal structure of 2-[4-(4-
methoxyphenoxycarbonyl)phenoxy]ethoxycarbonyl ferrocene was determined by
X-ray diffraction method using a single crystal. The molecular structure revealed
a bent structure that is almost a half of ‘‘Z’’ shaped molecular structure of 1,10-
bis[2-[4-(4-methoxyphenoxycarbonyl)phenoxy]ethoxycarbonyl]ferrocene.
Keywords Crystal structure; ferrocene; liquid crystal; metallomesogen; mono-
substituted ferrocene derivative
Introduction
Ferrocene, one of the metallocenes, contains an iron atom. As it has a thermal
stability and an aromaticity, the substitution reaction easily occurs under a mild
reaction condition. If a mesogenic group is introduced in the ferrocene molecule,
ꢀPresent address: TOYOBO Co., Ltd. 2-8, Dojima Hama 2-chome, Kita-ku, Osaka
530-8230, Japan.
ꢀꢀPresent address: Molex Japan Co., Ltd. 1-5-4, Fukami-higashi, Yamato, Kanagawa
242–8585, Japan.
ꢀꢀꢀPresent address: Unitika LTD, 31-3, Uji-hinojiri, Uji-city, Kyoto 611-0021, Japan.
A High-Tech Research Center Project for Private Universities matching fund subsidy
from Ministry of Education, Culture, Sports, Science and Technology, 2006–2010 is gratefully
acknowledged for partial financial support of the present work. We are grateful to Assoc.
Prof. T. Hanasaki, Ritsumeikan University for his useful discussion on the molecular design,
and Mr. T. Takamatsu, Ritsumeikan University for his support of structure analysis.
Address correspondence to Naotake Nakamura, Department of Applied Chemistry,
College of Science and Engineering, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu,
Shiga 525-8577, Japan. E-mail: nakamura@sk.ritsumei.ac.jp
122

Synthesis and Physical Properties of Ferrocene Derivatives (XXIII)
123
Figure 1. General structure of bMAF-n.
Figure 2. General structure of mMAF-n.
the ferrocene derivative may show a liquid crystallinity. The derivative is one of the
metallomesogens, which shows unique physical properties [1,2].
In our laboratory, a series of disubstituted ferrocene derivatives, 1,10-bis[x-[4-(4-
methoxyphenoxycarbonyl)phenoxy]alkoxycarbonyl]ferrocene (abbreviated hereafter
as bMAF-n, n ¼ 2ꢀ12, where n is the number of carbon atoms in the methylene chain)
were prepared [3,4]. A general structure of bMAF-n is shown in Figure 1. In the homo-
logues, bMAF-3 and 5ꢀ12 show liquid crystalline phases. In contrast, bMAF-2 and 4
have no liquid crystalline phase [3,4]. We have already determined the crystal structures
of bMAF-2 [5], 3 [6], 5 [7], 9 [8] and 10 [9]. The molecular structure of bMAF-2 [5] was
‘‘Z’’ shaped conformation, bMAF-3 [6] was ‘‘U’’ shaped one, and that of bMAF-5 [7]
was ‘‘S’’ shaped one, whereas the molecular structures of bMAF-9ꢀ10 were ‘‘U’’ shaped
one. The two substituents in the ‘‘Z’’ and ‘‘S’’ shaped conformations exist in the opposite
sides with respect to the ferrocenyl moiety. On the other hand, the two substituents in the
‘‘U’’ shaped one exist in the same side of the ferrocenyl moiety. It could be considered
that the ‘‘Z’’ shaped conformation is the modified ‘‘S’’ shaped conformation.
In this study, monosubstituted ferrocene derivatives containing the same
substituent of bMAF-n (n ¼ 2ꢀ12) are prepared in order to compare the liquid crys-
tallinity between the disubstituted ferrocene derivatives and the monosubstituted
ones. A general structure of the monosubstituted ferrocene derivatives is shown in
Figure 2. The name of the compound studied here is x-[4-(4-methoxyphenoxycarbo-
nyl)phenoxy]alkoxycarbonyl ferrocene (abbreviated hereafter as mMAF-n, where n
means the same as that of bMAF-n).
In addition, a crystal structure analysis of mMAF-2 is carried out using single
crystal X-ray diffraction method, because the structure analysis enables us to know
interrelations between the crystal structure and some physical properties.
Experimental
A synthetic route of mMAF-n is shown in Figure 3. After purification using an open
column chromatography, the products were identified as the objective compounds
1
by H-NMR (JEOL, ALPHA-400 (400 MHz)) spectrometer.
NMR data are as follows;
mMAF-2
1H-NMR (CDCl3) d: 8.16 (d, 2H, J ¼ 8.8 Hz), 7.11 (td, 2H, J ¼ 6.2, 4.1 Hz), 7.05
(d, 2H, J ¼ 8.8 Hz), 6.95–6.92 (m, 2H), 4.84 (t, 2H, J ¼ 1.7 Hz), 4.62 (t, 2H,

124
N. Nakamura et al.
Figure 3. Synthetic route of mMAF-n, where n is the number of carbon atoms in the methyl-
ene chain.
J ¼ 4.6 Hz), 4.42 (t, 2H, J ¼ 2.0 Hz), 4.37 (t, 2H, J ¼ 4.6 Hz), 4.19 (s, 5H), 3.82
(s, 3H).
mMAF-3
1H-NMR (CDCl3) d: 8.15 (d, 2H, J ¼ 8.8 Hz), 7.11 (dd, 2H, J ¼ 6.8, 2.0 Hz), 7.01
(d, 2H, J ¼ 8.8 Hz), 6.95–6.92 (m, 2H), 4.81 (t, 2H, J ¼ 2.0 Hz), 4.43 (dt, 4H, J ¼ 13.2,
4.1 Hz), 4.22 (t, 2H, J ¼ 6.1 Hz), 4.18 (d, 5H, J ¼ 4.4 Hz), 3.82 (s, 3H), 2.30–2.24
(m, 2H).
mMAF-4
1H-NMR (CDCl3) d: 8.14 (d, 2H, J ¼ 8.8 Hz), 7.12 (t, 2H, J ¼ 4.4 Hz), 6.99 (d,
2H, J ¼ 8.8 Hz), 6.93 (d, 2H, J ¼ 8.8 Hz), 4.81 (t, 2H, J ¼ 2.0 Hz), 4.41 (t, 2H,
J ¼ 2.0 Hz), 4.32 (t, 2H, J ¼ 6.1 Hz), 4.21 (s, 4H), 4.14 (t, 2H, J ¼ 5.9 Hz), 3.83 (s,
3H), 2.02–1.95 (m, 4H).
mMAF-5
1H-NMR (CDCl3) d: 8.14–8.12 (m, 2H), 7.13–7.09 (m, 2H), 7.00–6.92 (m, 4H),
4.81 (t, 2H, J ¼ 1.8 Hz), 4.40 (t, 2H, J ¼ 1.8 Hz), 4.27 (t, 2H, J ¼ 6.5 Hz), 4.21 (s, 5H),
4.09 (t, 2H, J ¼ 6.3 Hz), 3.82 (s, 3H), 1.92 (q, 2H, J ¼ 7.2 Hz), 1.82 (dd, 2H, J ¼ 14.6,
6.6 Hz), 1.66 (q, 2H, J ¼ 5.4 Hz).

Synthesis and Physical Properties of Ferrocene Derivatives (XXIII)
mMAF-6
125
1H-NMR (CDCl3) d: 8.13 (d, 2H, J ¼ 8.8 Hz), 7.12 (d, 2H, J ¼ 9.3 Hz), 6.95
(dd, 4H, J ¼ 13.2, 8.8 Hz), 4.81 (t, 2H, J ¼ 2.0 Hz), 4.39 (t, 2H, J ¼ 1.7 Hz),
4.24–4.22 (m, 7H), 4.10 (dd, 2H, J ¼ 18.5, 12.2 Hz), 3.83 (s, 3H), 1.87 (d, 2H,
J ¼ 8.8 Hz), 1.79 (t, 2H, J ¼ 7.3 Hz), 1.55 (s, 4H).
mMAF-7
1H-NMR (CDCl3) d: 8.13 (d, 2H, J ¼ 8.3 Hz), 7.12 (d, 2H, J ¼ 8.8 Hz), 6.95 (dd,
4H, J ¼ 11.2, 8.8 Hz), 4.81 (d, 2H, J ¼ 1.5 Hz), 4.40 (d, 2H, J ¼ 1.5 Hz), 4.22 (q, 7H,
J ¼ 5.7 Hz), 4.06 (t, 2H, J ¼ 6.3 Hz), 3.83 (s, 3H), 1.86 (t, 2H, J ¼ 7.1 Hz), 1.76 (t, 2H,
J ¼ 7.1 Hz), 1.51–1.48 (m, 6H).
mMAF-8
1H-NMR (CDCl3) d: 8.13 (t, 2H, J ¼ 4.4 Hz), 7.13–7.10 (m, 2H), 6.97–6.92 (m,
4H), 4.81 (t, 2H, J ¼ 2.0 Hz), 4.39 (t, 2H, J ¼ 2.0 Hz), 4.22 (q, 7H, J ¼ 5.2 Hz), 4.04 (t,
2H, J ¼ 6.6 Hz), 3.83 (s, 3H), 1.83 (q, 2H, J ¼ 7.0 Hz), 1.74 (t, 2H, J ¼ 7.1 Hz), 1.47
(d, 8H, J ¼ 21.0 Hz).
mMAF-9
1H-NMR (CDCl3) d: 8.13 (d, 2H, J ¼ 8.3 Hz), 7.12 (d, 2H, J ¼ 8.3 Hz), 6.95 (t,
4H, J ¼ 9.5 Hz), 4.81 (d, 2H, J ¼ 1.5 Hz), 4.39 (d, 2H, J ¼ 2.0 Hz), 4.22 (q, 7H,
J ¼ 4.4 Hz), 4.04 (t, 2H, J ¼ 6.6 Hz), 3.83 (s, 3H), 1.83 (t, 2H, J ¼ 7.6 Hz), 1.74 (t,
2H, J ¼ 7.3 Hz), 1.43 (d, 10H, J ¼ 33.2 Hz).
mMAF-10
1H-NMR (CDCl3) d: 8.13 (d, 2H, J ¼ 9.3 Hz), 7.12 (t, 2H, J ¼ 4.4 Hz), 6.95 (td,
4H, J ¼ 7.3, 3.4 Hz), 4.81 (t, 2H, J ¼ 2.0 Hz), 4.39 (t, 2H, J ¼ 2.0 Hz), 4.22 (t, 7H,
J ¼ 6.1 Hz), 4.03 (t, 2H, J ¼ 6.6 Hz), 3.82 (s, 3H), 1.85–1.79 (m, 2H), 1.72 (q, 2H,
J ¼ 7.0 Hz), 1.41 (d, 12H, J ¼ 44.9 Hz).
mMAF-11
1H-NMR (CDCl3) d: 8.13 (d, 2H, J ¼ 8.3 Hz), 7.11 (d, 2H, J ¼ 8.8 Hz), 6.95 (t,
4H, J ¼ 9.8 Hz), 4.81 (d, 2H, J ¼ 2.0 Hz), 4.39 (d, 2H, J ¼ 10.0 Hz), 4.22–4.20 (m,
7H), 4.03 (t, 2H, J ¼ 6.6 Hz), 3.82 (s, 3H), 1.82 (t, 2H, J ¼ 7.1 Hz), 1.73 (t, 2H,
J ¼ 7.1 Hz), 1.45–1.34 (m, 12H).
mMAF-12
1H-NMR (CDCl3) d: 8.13 (d, 2H, J ¼ 8.8 Hz), 7.12 (d, 2H, J ¼ 8.8 Hz), 6.95 (dd,
4H, J ¼ 11.2, 8.8 Hz), 4.81 (s, 2H), 4.39 (s, 2H), 4.22–4.21 (m, 7H), 4.04 (t, 2H,
J ¼ 6.3 Hz), 3.83 (s, 3H), 1.82 (t, 1H, J ¼ 7.1 Hz), 1.73 (t, 1H, J ¼ 7.3 Hz),
1.45–1.31 (m, 13H).
Phase transition phenomena of mMAF-n were measured using Diamond
DSC (Perkin Elmer) with heating and cooling rates of 5ꢁC=min. The textures
in the liquid crystalline phases were observed by a Nikon ECLIPSE E600 optical
polarizing microscope equipped with a heating stage (Mettler Toledo FP90)
of which heating and cooling rates are 5ꢁC=min, as same as those of DSC
measurements.
Single crystals of mMAF-2 were grown by the slow evaporation method from a
mixed solvent solution of methylene chloride and ethanol (5:3). The single crystals
obtained were block-like and orange in color. The sample, of which the dimensions
were 0.50 ꢂ 0.32 ꢂ 0.17 mm, was mounted on a goniometer.

126
N. Nakamura et al.
All measurements were carried out at the temperature, 296(2) K, using a Rigaku
AFC-5R diffractometer with graphite-monochromated Cu Ka radiation. The inten-
sity data were corrected for Lorentz and polarization effects. Absorption corrections
by Gaussian from the crystal shape [10] and decay corrections were applied. Second-
ary extinction corrections were also applied [11].
All non-hydrogen atoms were refined anisotropically. Isotropic displacement
parameters of aromatic- and methylene-H atoms were set to be 1.2 Ueq of the parent
atom, and those of methyl-H atoms were set to be 1.5 Ueq. The aromatic- and
methylene-H atoms were located at idealized positions and were allowed to ride
˚
˚
on the parent carbon atom (CꢃH ¼ 0.93 A for the aromatic parts, CꢃH ¼ 0.97 A
for the methylene parts). The methyl-H atoms were located with idealized torsion
angles by a rotating group refinement, and were allowed to ride on the parent carbon
atom (CꢃH ¼ 0.96 A).
˚
Computing Details
Data collection: MSC=AFC Diffractometer Control Software [12]; cell refinement:
MSC=AFC Diffractometer Control Software; data reduction: CrystalStructure [13];
program(s) used to solve structure: SIR92 [14]; program(s) used to refine structure:
SHELXL97 [11]; molecular graphics: ORTEP-3 for Windows [15]; software used to
prepare material for publication: WinGX [16].
Results and Discussion
Phase Transition Behavior
Phase transition temperatures of mMAF-n (n ¼ 2ꢀ12) obtained on cooling are
shown in Figure 4. Only 4 members, that is mMAF-9ꢀ12, exhibited liquid crystalline
phases, while the others were not shown. Every liquid crystalline member has two
phases. The identification of liquid crystalline phases by polarizing microscopic
observation is difficult, but it suggests that L.C.1 and L.C.2 are nematic phase
and smectic one, respectively. These liquid crystalline phases are located around
room temperature region and the temperature range is about 25–37ꢁC.
Figure 5 shows a phase transition diagram of bMAF-n (n ¼ 2ꢀ12) already
reported [4]. Except bMAF-2 and 4, all the members showed a liquid crystalline
phase. The bMAF-3 showed only nematic phase (L.C.1 in Figure 5) identified by
polarizing microscopic observation in addition to X-ray measurement. The members
of bMAF-5ꢀ10 exhibited two phases, L.C.1 and L.C.2, while the members of
bMAF-11ꢀ12 had L.C.3 in addition to L.C.1 and L.C.2. From the polarizing micro-
scopic observations and the X-ray measurements, L.C.2 and L.C.3 are regarded as
smectic C and smectic F or I phases, respectively [4]. Here, pay attention that
L.C.1 and L.C.2 in the Figures 4 and 5 are not the same.
From the results obtained by X-ray structure analyses of bMAF-n, it is con-
sidered that an aspect ratio of these liquid crystalline molecules is large enough to
exhibit a liquid crystalline phase. The ratio is one of the most important factors to
appear a liquid crystalline phase. Therefore, the members of bMAF-5ꢀ12 have
the stable liquid crystalline phase of which temperature range is wider than that of
the liquid crystalline mMAF-n. The liquid crystalline phase of the bMAF-n is
located in rather higher region compared with that of the mMAF-n. In the case of

Synthesis and Physical Properties of Ferrocene Derivatives (XXIII)
127
Figure 4. Phase transition behavior of mMAF-n (on cooling). I: Isotropic liquid; L.C.1:
Liquid crystalline phase (ꢀNematic); L.C.2: Liquid crystalline phase (ꢀSmectic); G: Glass
state.
Figure 5. Phase transition behavior of bMAF-n (on cooling). I: Isotropic liquid; L.C.1: Liquid
crystalline phase (Nematic); L.C.2: Liquid crystalline phase (Smectic C); L.C.3: Liquid crystal-
line phase (Smectic F or I); G: Glass state.

128
N. Nakamura et al.
liquid crystalline bMAF-3 of which the length of substituent is not long enough,
another reason may exist to show a liquid crystallinity.
In the series of bMAF-n, longer members tended to show a liquid crystalline
phase, but shorter ones didn’t, and the similar tendency was observed in the series
of mMAF-n. Figure 6 showed a carbon number dependence of clearing temperatures
of bMAF-n and mMAF-n. The clearing temperatures of bMAF-n increase with
increasing the carbon number accompanying with a typical odd-even effect. The
odd-even effect of bMAF-n became less remarkable with increasing the carbon num-
ber, and finally it converges to about 60ꢁC [4]. In other word, no odd-even effect
around bMAF-11ꢀ12 was observed, though 11 is odd and 12 is even.
On the other hand, no odd-even effect was observed in the series of mMAF-n.
The longer members, mMAF-9ꢀ12, showed liquid crystalline phases. The mMAF-
n has only two phenyl rings in the one mesogenic group, though the phenyl group
of bMAF-n is a double because the number of mesogenic groups is two. As an
existence of the phenyl ring is one of the most important factors to appear a liquid
crystalline phase. Therefore, the mMAF-n is disadvantageous compared with the
bMAF-n. Although a carbon number dependence of glass transition temperatures
is not shown in Figure 6, it indicates a linear relation from 7.8ꢁC of mMAF-2
through ꢃ17ꢁC of mMAF-8. The glass transition temperatures of higher members,
mMAF-9ꢀ12, are about ꢃ18ꢁC. If the curve of clearing points is extrapolated to
lower members, it seems likely to appear a liquid crystalline phase around
mMAF-7ꢀ8. In fact, slightly small peaks were observed successively on a cooling
DSC curve of mMAF-8 around 5ꢁC. Although no texture change was detected in
the polarizing microscopic observation around 5ꢁC, these slightly small peaks may
Figure 6. Carbon number dependence of clearing temperatures (Tcl) of bMAF-n and mMAF-
n (on cooling).

Synthesis and Physical Properties of Ferrocene Derivatives (XXIII)
129
Table 1. The summarized crystallographic data and the
results of the final refinement of mMAF-2
Empirical formula
Formula weight
Crystal system
Space group
C27H24FeO6
500.31
triclinic
P-1
˚
a=A
5.9118 (7)
13.7485 (9)
14.4799 (12)
86.019 (7)
87.113 (10)
78.399 (7)
1149.28 (18)
2
˚
b=A
˚
c=A
a=ꢁ
b=ꢁ
c=ꢁ
3
˚
Volume=A
Z value
D
calc=gcmꢃ3
Measured reflections
1.446
4647
Independent reflections
Parameters
4191
309
Extinction coefficient
R
wR(F2)
0.0069(4)
0.033
0.091
S
1.06
CCDC 707627 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge via www.
ccdc.cam.ac.uk/data_request/cif, or by emailing data request@
ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic
Data Centre, 12, Union Road, Cambridge CB2 1EZ, UK; fax: þ44
1223 336033.
correspond to the clearing and glass transition points. As a result, it needs to con-
tinue a careful survey on the liquid crystalline phase transition in mMAF-7ꢀ8.
In order to discuss about the phase transition phenomena including the liquid
crystalline phase transition in detail, the structure analysis of mMAF-2 was carried
out as an example. The summarized crystallographic data and the results of the final
refinement are shown in Table 1.
Molecular Structure
ORTEP-3 [15] drawing, the molecular structure of mMAF-2 with numbering for
each atom is presented in Figure 6 where the hydrogen atoms are omitted for a
simplification, together with that of bMAF-2 [5, (reproduced with the permission
of Chemistry Letters, Copyright 2005, The Chemical Society of Japan.)] as a
reference.
In the ferrocenyl moiety of mMAF-2, two cyclopentadienyl rings were almost
parallel but not complete because the dihedral angle was calculated at 2.59(16)ꢁ.
Two cyclopentadienyl rings assumed almost eclipsed conformation rather than stag-
gered one. The eclipsed one has been found in monosubstituted ferrocene derivatives
[17–21] of which the substituent structures are different from those of mMAF-n.

130
N. Nakamura et al.
Figure 7. ORTEP-3 [15] views of the molecular structures excluding hydrogen atoms in (a)
mMAF-2 and (b) bMAF-2 [5, (reproduced with the permission of Chemistry Letters, Copy-
right 2005, The Chemical Society of Japan.)]. Thermal ellipsoids are drawn at 50% probability.
The average values of the Fe-C and C-C bond distances in the ferrocenyl moiety of
˚
˚
mMAF-2 were 2.036(7)A and 1.408(13)A, respectively. The C-C-C bond angles in the
cyclopentadienyl rings were 108.0(8)ꢁ on average. These values are good agreement
with those of ferrocene reported by Dunitz et al. [22] within an experimental error.
In the molecular structure of mMAF-2, the torsion angles of C(11)-O(1)-
C(12)-C(13) and O(1)-C(12)-C(13)-O(3) showed the gauche conformation. As a
result, the molecule bent over around the gauche conformation. This kind of bent
structure is disadvantageous to showing a liquid crystalline phase. In fact, mMAF-2
didn’t show a liquid crystalline phase as well as bMAF-2 [5]. As a topic of a great
interest, the molecular structure of mMAF-2 is almost a half of that of bMAF-2,
as is easily seen in Figure 7.
Crystal structure analyses of mMAF-n except mMAF-2 are now in progress.
The results obtained will be discussed from a viewpoint of the phase transition
behavior including that of mMAF-2.
References
[1] Carano, M., Chuard, T., Deschenaux, R., Even, M., Maraccio, M., Paolucci, F., Parato,
M., & Roffia, S. (2002). J. Matter. Chem., 12, 829.
[2] Even, M., Heinrich, B., Guillon, D., Guldi, D. M., Parato, M., & Deschenaux, R. (2001).
Chem. Eur. J., 7, 2595.

Synthesis and Physical Properties of Ferrocene Derivatives (XXIII)
131
[3] Hanasaki, T., Ueda, M., & Nakamura, N. (1994). Mol. Cryst. Liq. Cryst., 250, 257.
[4] Nakamura, N., Mizoguchi, R., Ueda, M., & Hanasaki, T. (1998). Mol. Cryst. Liq. Cryst.,
312, 127.
[5] Nakamura, N. & Nishikawa, M. (2005). Chem. Lett., 34, 1544.
[6] Okabe, T., Nakazaki, K., Igaue, T., Nakamura, N., Donnio, B., Guillon, D., & Gallani,
J.-L. (2008). J. Appl. Cryst., to be submitted.
[7] Nakamura, N., Okabe, T., & Takahashi, T. (2005). Mol. Cryst. Liq. Cryst., 441, 243.
[8] Nakamura, N., Nio, T., Okabe, T., Donnio, B., Guillon, D., & Gallani, J.-L. (2007). Mol.
Cryst. Liq. Cryst., 466, 3.
[9] Nakamura, N. & Okabe, T. (2004). Chem. Lett., 33, 358.
[10] Coppens, P., Leiserowitz, L., & Rabinovich, D. (1965). Acta Cryst., 18, 1035–1038.
[11] Sheldrick, G. M. (2008). Acta Cryst., A64, 112.
[12] Molecular Structure Corporation (1992). MSC=AFC Diffractometer Control Software.
MSC, The Woodlands, Texas, USA.
[13] Molecular Structure Corporation & Rigaku. (2001). CrystalStructure. Version 3.8.1.
MSC, The Woodlands, Texas, USA & Rigaku Corporation, Tokyo, Japan.
[14] Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G.,
& Camalli, M. (1994). J. Appl. Cryst., 27, 435.
[15] Farrugia, L. J. (1997). J. Appl. Cryst., 30, 565.
[16] Farrugia, L. J. (1999). J. Appl. Cryst., 32, 837–838.
[17] Nakamura, N. & Setodoi, S. (1999). Mol. Cryst. Liq. Cryst., 326, 177.
[18] Nakamura, N. & Setodoi, S. (1998). Mol. Cryst. Liq. Cryst., 319, 173.
[19] Nakamura, N., Takahashi, T., Uno, K., & Hanasaki, T. (2002). Mol. Cryst. Liq. Cryst.,
383, 27.
[20] Nakamura, N. & Setodoi, S. (1999). Mol. Cryst. Liq. Cryst., 333, 151.
[21] Nakamura, N., Setodoi, S., & Takayama, T. (2000). Mol. Cryst. Liq. Cryst., 346, 19.
[22] Dunitz, J. D., Orgel, L. E., & Rich, A. (1956). Acta. Cryst., 9, 373.