Cocrystals of 2,3,5,6-tetra-fluoro-benzene-1,4-diol with diaza aromatic compounds

Article abstract of DOI:10.1107/S0108270110021736

2,3,5,6-Tetra-fluoro-benzene-1,4-diol easily forms cocrystals with heteroaromatic bases containing the pyrazine unit. In the 1:1 complexes with pyrazine, C₆H₂4₆O₂·C ₄H₄N₂, (I), and quinoxaline, C ₆H₂F₄O₂·C₈H ₆N₂, (II), the crystal components are linked via O - H...N hydrogen bonds into one-dimensional chains. With the largest base, phenazine, the 1:2 benzenediol-phenazine complex, C₆H ₂F₄O₂·2C₁₂H₈N ₂, (III), was obtained, with the mol-ecules linked via O - H...N inter-actions into a discrete heterotrimer. In all three cocrystals, the two types of mol-ecules are organized into layers via softer C - H...O and C - H...F inter-actions and π-π stacking inter-actions, with stronger hydrogen bonds linking mol-ecules of adjacent layers. In (II) and (III), mol-ecules are arranged into heterostacks, whereas in (I) separate stacks are formed by the heterocyclic base and the benzene-diol molecule.

Full text of DOI:10.1107/S0108270110021736

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
molecular substrates. For example, Thalladi et al. (2000) have
shown that PHZ cocrystallizes with hydroquinone (HQ) in a
2:1 molar ratio to form a square-grid type host network
constructed from stacks of PHZ with the diphenol guest
molecules accommodated in channels, where they interact
with PHZ via hard hydrogen bonds, weak hydrogen bonds and
edge-to-face aromatic interactions. Some other diphenols give
a similar packing arrangement and their stoichiometries also
do not conform with the simple considerations of hydrogen-
bond requirements (Thalladi et al., 2000). Reducing the size of
the aromatic-ring system and lowering the symmetry of the
hetorocyclic base has basically no influence on the overall
packing mode, as shown by the structure of QX–HQ (2/1)
(Kadzewski & Gdaniec, 2006).
ISSN 0108-2701
Cocrystals of 2,3,5,6-tetrafluoro-
benzene-1,4-diol with diaza aromatic
compounds
Agnieszka Czapik and Maria Gdaniec*
´
Faculty of Chemistry, Adam Mickiewicz University, 60-780 Poznan, Poland
Correspondence e-mail: magdan@amu.edu.pl
Cocrystals of the three above-mentioned diaza heterocycles
with 3,6-dihydroxy-1,4-benzoquinones have been extensively
studied in relation to the interesting ferroelectric properties
exhibited by some members of this new group of materials
(Horiuchi, Ishii et al., 2005; Horiuchi, Kumai & Tokura, 2005;
Gotoh, Asaji & Ishida, 2007). They generally differ both in the
stoichiometry and in the packing mode observed in the
cocrystals compared with those with HQ. 2,5-Dibromo-3,6-
dihydroxy-1,4-benzoquinone (bromanilic acid, BrA; Tomura
& Yamashita, 2000) and 2,5-chloro-3,6-dihydroxy-1,4-benzo-
quinone (chloranilic acid, ClA; Gotoh, Asaji & Ishida, 2007;
Gotoh, Nagoshi & Ishida, 2007) cocrystallize with PHZ or QX
in a 1:1 ratio and the component molecules are connected
alternately by O—Hꢀ ꢀ ꢀN hydrogen bonds into robust poly-
meric chains. In addition, the aromatic heterobases and
diacids are arranged into segregated stacks via offset face-to-
face ꢀ–ꢀ stacking interactions. In the case of the cocrystal
PYZ–ClA (2/1), partial proton transfer from ClA to the base
influences the stoichiometry of the complex (Gotoh et al.,
2008).
Received 27 May 2010
Accepted 7 June 2010
Online 11 June 2010
2,3,5,6-Tetrafluorobenzene-1,4-diol easily forms cocrystals
with heteroaromatic bases containing the pyrazine unit. In
the 1:1 complexes with pyrazine, C6H2F4O2ꢀC4H4N2, (I), and
quinoxaline, C6H2F4O2ꢀC8H6N2, (II), the crystal components
are linked via O—Hꢀ ꢀ ꢀN hydrogen bonds into one-dimen-
sional chains. With the largest base, phenazine, the 1:2
benzenediol–phenazine complex, C6H2F4O2ꢀ2C12H8N2, (III),
was obtained, with the molecules linked via O—Hꢀ ꢀ ꢀN
interactions into a discrete heterotrimer. In all three
cocrystals, the two types of molecules are organized into
layers via softer C—Hꢀ ꢀ ꢀO and C—Hꢀ ꢀ ꢀF interactions and
ꢀ–ꢀ stacking interactions, with stronger hydrogen bonds
linking molecules of adjacent layers. In (II) and (III),
molecules are arranged into heterostacks, whereas in (I)
separate stacks are formed by the heterocyclic base and the
benzenediol molecule.
2,3,5,6-Tetrafluorobenzene-1,4-diol (TFHQ) has a similar
hydrogen-bond potential to HQ, but the electron density of
the aromatic ring is substantially reduced due to the presence
of the four electron-withdrawing F substituents. This has to
have an impact on the ability of the TFHQ aromatic ring to
participate in the edge-to-face interactions that are of primary
importance in the formation of channel-type structures in
cocrystals of HQ with PHZ or QX (Thalladi et al., 2000;
Kadzewski & Gdaniec, 2006). On the other hand, the lowered
electron density of the benzene ring in TFHQ should promote
the formation of mixed ꢀ stacks by interaction of TFHQ with
aromatic heterobases, by analogy with the robust packing
motif found in the arene–perfluoroarene systems (Collings et
al., 2002, and references therein). To see how the substitution
of hydroquinone C—H groups by C—F groups affects the
intermolecular interactions and crystal packing modes in two-
component systems composed of a diaza aromatic base and
hydroquinone, three cocrystals, namely TFHQ–PYZ (1/1), (I),
TFHQ–QX (1/1), (II), and TFQX–PHZ (1/2), (III), were
obtained and their structures studied by X-ray analyses.
The molecular structures of cocrystals (I)–(III), together
with their atom-numbering schemes, are shown in Fig. 1.
TFHQ cocrystallizes with PYZ and QX in a 1:1 molar ratio, as
Comment
Among the intermolecular interactions used to guide supra-
molecular synthesis are conventional (hard) hydrogen bonds,
weak (soft) hydrogen bonds, halogen bonds, aromatic-ring
interactions and electrostatic interactions. Very early on,
strong hydrogen bonds were recognized as a powerful orga-
nizing force determining the structure of many molecular
crystals. However, the formation of any supramolecular
structure is the result of a large number of interactions, and
the much weaker forces, often numerous and acting co-
operatively, can play a decisive role in determinining the
overall structure and stability of a supramolecular assembly.
The diaza aromatic weak bases phenazine (PHZ), quin-
oxaline (QX) and pyrazine (PYZ) have a similar potential to
form molecular complexes through hard hydrogen bonds.
However, the recognition process, which also involves weaker
interactions with the aromatic ꢀ system and the C—H groups,
can proceed differently, influencing the stoichiometry and the
packing mode of the substrates in the crystal structures. These
three aromatic heterocycles are considered as good supra-
o356 # 2010 International Union of Crystallography
doi:10.1107/S0108270110021736
Acta Cryst. (2010). C66, o356–o360

organic compounds
could be predicted from the number of hydrogen-bond donor
and acceptor groups. The cocrystal of PHZ and TFHQ
contains the two components in a 2:1 ratio, i.e. the stoichiom-
etry is the same as in the cocrystal of PHZ and HQ (Thalladi et
al., 2000). In (I), both crystal components lie on inversion
hydrogen bond formed with the weak organic bases and the
geometry of these hydrogen bonds, with Oꢀ ꢀ ꢀN distances in
˚
the range 2.7257 (14)–2.791 (3) A (Tables 2, 4 and 6), points to
a strong interaction. This should increase significantly the
electron density at the phenolic donor group, resulting in the
observed geometric changes in the molecular structure of
TFHQ. The O—Hꢀ ꢀ ꢀN hydrogen bonds observed in the three
cocrystals with TFHQ are also shorter than the hydrogen
˚
bonds formed by HQ with PHZ (2.815 A; Thalladi et al., 2000)
˚
and by HQ with QX [2.8425 (18) A; Kadzewski & Gdaniec,
2006], in accord with the increased acidity of TFHQ relative to
HQ.
The hydrogen-bonding O—Hꢀ ꢀ ꢀN interaction between the
two cocrystal components is the strongest specific interaction
that organizes the molecules into polymeric chains [(I) and
(II)] or into discrete heterotrimers [(III)]. To avoid repulsive
Hꢀ ꢀ ꢀF interactions between molecules brought close together
by hydrogen bonding, they have to twist substantially along
the Oꢀ ꢀ ꢀN line of the intermolecular O—Hꢀ ꢀ ꢀN hydrogen
bond. The dihedral angle between interacting molecules
increases slightly with the increase of the aromatic system of
the base and ranges from 43.97 (7)ꢁ in (I) through 48.50 (4)
and 47.63 (4)ꢁ in (II) to 49.32 (2)ꢁ in (III), whereas the shortest
Hꢀ ꢀ ꢀF distance between the hydrogen-bonded components
centres. In (III), only the TFHQ molecule is located on a
special position of Ci symmetry, whereas in (II), all the mol-
ecules are in general positions. The geometry of TFHQ in the
three cocrystals is virtually the same (Tables 1, 3 and 5), with
the C—O bond lengths ranging from 1.3504 (15) to
˚
1.352 (3) A, and the endocyclic angles at the C atoms attached
to the OH groups in the range 115.6 (2)–115.76 (12)ꢁ. A value
smaller than 120ꢁ for this bond angle is consistent with the
electron-donating character of the hydroxy groups (Domeni-
cano et al., 1975). Nevertheless, the observed values are ca 1.5ꢁ
smaller than in the TFHQ molecule in its anhydrous and
hydrated forms (117.1–117.5ꢁ; Thalladi et al., 1999; Rusak &
Gdaniec, 2006). Significant differences are also found in the
C—O bond lengths, which in the above-mentioned crystalline
changes from 2.62 A in (II) to 2.81 A in (III). Similar twist
angles were observed in the cocrystals of BrA with QX (49.8ꢁ)
and PHZ (45.3ꢁ), leading to Hꢀ ꢀ ꢀO distances between
˚
˚
˚
hydrogen-bonded partners of 2.80 and 2.57 A, respectively
(Tomura & Yamashita, 2000).
The crystal packing in (I), together with the most important
intermolecular synthons, is illustrated in Fig. 2. Alternating
PYZ and TFHQ molecules, connected via O—Hꢀ ꢀ ꢀN
hydrogen bonds (Table 2), form polymeric chains extending
along [111]. Another chain is formed in the [111] direction via
softer C—Hꢀ ꢀ ꢀO and C—Hꢀ ꢀ ꢀF interactions. The latter
corrugated chains stack one above the other in a manner
˚
forms of TFHQ are longer (1.362–1.367 A). All these changes
in the molecular geometry can be attributed to hydrogen-bond
interactions involving the hydroxy group. In cocrystals (I)–
(III), the OH groups donate an H atom to the O—Hꢀ ꢀ ꢀN
Figure 1
The molecular structures of (a) (I), (b) (II) and (c) (III), showing the atom-numbering schemes. Displacement ellipsoids are drawn at the 50%
probability level and H atoms are shown as small spheres of arbitrary radii. Hydrogen bonds are shown as dashed lines. [Symmetry codes: (i) 1 ꢃ x, 1 ꢃ y,
1 ꢃ z: (ii) 2 ꢃ x, ꢃy, ꢃz.]
ꢂ
Acta Cryst. (2010). C66, o356–o360
Czapik and Gdaniec
C6H2F4O2ꢀC4H4N2, C6H2F4O2ꢀC8H6N2 and C6H2F4O2ꢀ2C12H8N2 o357

organic compounds
Figure 3
The crystal packing of (II), showing the intermolecular synthons. O, Fand
N atoms are represented as spheres of arbitrary radii. Hydrogen bonds
are shown as dashed lines.
Figure 2
The crystal packing of (I), showing the intermolecular synthons. O, F and
N atoms are represented as spheres of arbitrary radii. Hydrogen bonds
are shown as dashed lines.
leading to the formation of separate stacks of PZ and TFHQ
via offset face-to-face ꢀ–ꢀ stacking interactions. In effect, the
softer interactions assemble the molecules into (011) layers,
whereas the hard O—Hꢀ ꢀ ꢀN interactions connect molecules
from adjacent layers.
As illustrated in Fig. 3, the polymeric chains formed via O—
Hꢀ ꢀ ꢀN hydrogen bonds in (II) differ in shape from those in (I),
as the two chains have different rod group symmetries.
Whereas the chains in (I) are centrosymmetric and belong to
the P1 rod group, in (II) the hydrogen-bonded chains exhibit a
noncrystallographic centrosymmetric structure belonging to
the P121/m1 rod group, with the twofold screw axis directed
along the c axis; the pseudo-mirror plane is perpendicular to
the QX aromatic system and the pseudo-inversion centre is at
the centroid of the TFHQ benzene ring. The structure and
symmetry of this chain resemble very closely those of the
hydrogen-bonded chain of the QNX–BrA (1/1) cocrystal
(Tomura & Yamashita, 2000). Nevertheless, the packing
modes of these centrosymmetric assemblies are different,
because in (II) the crystal structure is chiral, as shown by the
P212121 space-group symmetry. Unlike in cocrystals of QX
with HQ, ClA or BrA, ꢀ–ꢀ stacking interactions between QX
and TFHQ result in heterostacks that are formed along the b
axis, with alternating aromatic bases and benzenediol mol-
ecules. Within the stack, the distances between the centroid of
TFHQ and the centroids of the pyrazine (symmetry code:
Figure 4
The crystal packing of (III), showing the intermolecular synthons. O, F
and N atoms are represented as spheres of arbitrary radii. Hydrogen
bonds are shown as dashed lines.
layers by soft C—Hꢀ ꢀ ꢀO and C—Hꢀ ꢀ ꢀF interactions to form
heterodimers. Again, the molecules are arranged via soft
interactions into layer-type assemblies, whereas the strongest
O—Hꢀ ꢀ ꢀN interactions operate between molecules from
adjacent layers. In addition to the O—Hꢀ ꢀ ꢀN hydrogen bonds,
molecules from adjacent layers are also connected via C—
Hꢀ ꢀ ꢀF interactions (Table 4).
Despite the change in stoichiometry, layers formed via
softer C—Hꢀ ꢀ ꢀO and C—Hꢀ ꢀ ꢀF hydrogen bonds and offset
face-to-face stacking interactions are also found in (III). The
molecules are connected via soft C—Hꢀ ꢀ ꢀO and C—Hꢀ ꢀ ꢀF
hydrogen bonds into heterotrimers that stack into (001) layers
via ꢀ–ꢀ interactions (Fig. 4, lower left; Table 6). The hetero-
stacks thus formed are extended along the b axis and each
TFHQ molecule is surrounded by two PHZ molecules, with a
1
1 ꢃ x, 12 + y, 32 ꢃ z) and benzene (symmetry code: 1 ꢃ x, ꢃ + y,
2
3
˚
ꢃ z) rings of QX are 3.824 (2) and 3.640 (2) A, respectively.
2
Molecules from neighbouring stacks are connected into (001)
ꢂ
o358 Czapik and Gdaniec
C6H2F4O2ꢀC4H4N2, C6H2F4O2ꢀC8H6N2 and C6H2F4O2ꢀ2C12H8N2
Acta Cryst. (2010). C66, o356–o360

organic compounds
Table 1
Selected geometric parameters (A, ) for (I).
distance between the TFHQ centroid and the centroid of the
˚
PHZ pyrazine unit of 3.7053 (7) A. In turn, each PHZ mol-
ꢁ
˚
ecule in the stack is surrounded by TFHQ and PHZ molecules,
and the distance between the centroids of the benzene and
pyrazine fragments (symmetry code: ꢃx, 1 ꢃ y, ꢃz) of the two
O1—C1
1.352 (2)
O1—C1—C2
O1—C1—C3
125.50 (15)
118.87 (14)
C2—C1—C3
115.62 (15)
˚
PHZ molecules is 3.6059 (8) A. As in the cocrystals (I) and
(II), hard O—Hꢀ ꢀ ꢀN hydrogen bonds link molecules from
adjacent layers (Fig. 4, upper left), but only discrete hetero-
trimers are formed. There is also a weak interlayer C—Hꢀ ꢀ ꢀN
interaction involving PHZ molecules.
Table 2
Hydrogen-bond geometry (A, ) for (I).
ꢁ
˚
D—Hꢀ ꢀ ꢀA
D—H
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
D—Hꢀ ꢀ ꢀA
In summary, layer-type assemblies generated by weak
hydrogen bonds and ꢀ–ꢀ stacking interactions, with stronger
hydrogen bonds acting between the layers, are a common
structural feature of the cocrystals formed by the benzenediols
HQ or TFHQ with the diaza aromatic heterobases QX or
PHZ. In cocrystals with HQ, the layer-type assemblies are
similarly constructed, with face-to-face stacking interactions
arranging the heterocyclic molecules into homostacks, and
HQ molecules, involved in edge-to-face interactions with the
heterobase and in weak hydrogen bonds, inserted between the
stacks. In turn, TFHQ molecules, with reduced electron
density of the aromatic ꢀ system and increased electron
density of the lateral groups, prefer to form heterostacks and
weak hydrogen bonds with the heterobase. Nevertheless, the
layer-type assemblies composed from the aromatic hetero-
cycles and TFHQ involved in a similar ‘set’ of intermolecular
interactions have a different structure in the case of cocrystals
with QX and PHZ.
O1—H1Oꢀ ꢀ ꢀN1A
C2A—H2Aꢀ ꢀ ꢀF3i
C3A—H3Aꢀ ꢀ ꢀO1ii
Symmetry codes: (i) x þ 1; y ꢃ 1; z; (ii) ꢃx þ 1; ꢃy þ 1; ꢃz.
0.85
0.96
0.96
1.90
2.64
2.62
2.7343 (19)
3.350 (2)
3.538 (2)
167
131
159
Compound (II)
Crystal data
3
˚
C6H2F4O2ꢀC8H6N2
V = 1263.2 (7) A
Z = 4
Mo Kꢁ radiation
ꢄ = 0.15 mmꢃ1
T = 294 K
Mr = 312.22
Orthorhombic, P212121
˚
a = 7.2094 (5) A
˚
b = 7.4290 (4) A
˚
c = 23.585 (13) A
0.60 ꢄ 0.40 ꢄ 0.40 mm
Data collection
Kuma KM-4 CCD diffractometer in
ꢅ geometry
6629 measured reflections
1324 independent reflections
1208 reflections with I > 2ꢆ(I)
Rint = 0.037
Table 3
Selected geometric parameters (A, ) for (II).
ꢁ
˚
Experimental
Cocrystals (I)–(III) were obtained by dissolving 2,3,5,6-tetrafluoro-
benzene-1,4-diol and the corresponding aromatic diaza heterocycles
(Aldrich) in a 1:1 molar ratio in cold [for (I) and (II)] or hot [for (III)]
ethanol. The solutions were allowed to evaporate slowly and the
precipitated crystals, suitable for X-ray analysis, were separated by
filtration.
O1—C1
1.352 (3)
O4—C4
1.355 (3)
O1—C1—C2
O1—C1—C6
C2—C1—C6
124.73 (19)
119.7 (2)
115.6 (2)
O4—C4—C5
O4—C4—C3
C5—C4—C3
124.83 (18)
119.6 (2)
115.5 (2)
Table 4
Hydrogen-bond geometry (A, ) for (II).
Compound (I)
ꢁ
˚
Crystal data
D—Hꢀ ꢀ ꢀA
D—H
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
D—Hꢀ ꢀ ꢀA
C6H2F4O2ꢀC4H4N2
ꢃ = 77.41 (2)ꢁ
V = 259.34 (11) A
Z = 1
Mo Kꢁ radiation
ꢄ = 0.17 mmꢃ1
T = 294 K
0.60 ꢄ 0.15 ꢄ 0.05 mm
3
˚
O1—H1Oꢀ ꢀ ꢀN1A
O4—H4Oꢀ ꢀ ꢀN4Ai
C2A—H2Aꢀ ꢀ ꢀF3ii
C3A—H3Aꢀ ꢀ ꢀO4ii
C7A—H7Aꢀ ꢀ ꢀF2iii
C6A—H6Aꢀ ꢀ ꢀF5iv
0.85
0.85
0.96
0.96
0.96
0.96
1.94
1.98
2.45
2.61
2.53
2.54
2.776 (3)
2.791 (3)
3.399 (3)
3.282 (3)
3.156 (3)
3.068 (3)
168
160
169
127
123
114
Mr = 262.17
Triclinic, P1
˚
a = 3.6671 (10) A
˚
b = 7.585 (2) A
˚
c = 9.582 (2) A
ꢁ = 88.14 (2)ꢁ
ꢂ = 85.67 (2)ꢁ
3
2
1
2
1
2
3
2
Symmetry codes: (i) ꢃx þ ; ꢃy þ 1; z þ ; (ii) ꢃx þ 2; y ꢃ ; ꢃz þ ; (iii) x ꢃ 1; y; z; (iv)
1
2
1
2
ꢃx þ ; ꢃy þ 1; z ꢃ .
Data collection
Kuma KM-4 CCD diffractometer in
ꢅ geometry
1921 measured reflections
917 independent reflections
791 reflections with I > 2ꢆ(I)
Rint = 0.041
Table 5
Selected geometric parameters (A, ) for (III).
ꢁ
˚
O1—C1
1.3504 (15)
Refinement
R[F2 > 2ꢆ(F2)] = 0.048
wR(F2) = 0.132
S = 1.08
82 parameters
H-atom parameteꢃrs3 constrained
O1—C1—C2
O1—C1—C3i
125.05 (12)
119.19 (11)
C2—C1—C3i
115.76 (12)
˚
Áꢇmax = 0.37 e A
ꢃ3
˚
917 reflections
Áꢇmin = ꢃ0.31 e A
Symmetry code: (i) ꢃx þ 1; ꢃy þ 1; ꢃz þ 1.
ꢂ
Acta Cryst. (2010). C66, o356–o360
Czapik and Gdaniec
C6H2F4O2ꢀC4H4N2, C6H2F4O2ꢀC8H6N2 and C6H2F4O2ꢀ2C12H8N2 o359

organic compounds
˚
lated postions and treated as riding atoms, with O—H = 0.85 A and
˚
C—H = 0.96 A, and with Uiso(H) = 1.2Ueq(O,C).
Table 6
Hydrogen-bond geometry (A, ) for (III).
ꢁ
˚
For all compounds, data collection: CrysAlis CCD (Oxford
Diffraction, 2004); cell refinement: CrysAlis CCD; data reduction:
CrysAlis RED (Oxford Diffraction, 2004); program(s) used to solve
structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine
structure: SHELXL97 (Sheldrick, 2008); molecular graphics:
ORTEP-3 for Windows (Farrugia, 1997) and Mercury (Macrae et al.,
2006); software used to prepare material for publication:
SHELXL97.
D—Hꢀ ꢀ ꢀA
D—H
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
D—Hꢀ ꢀ ꢀA
O1—H1Oꢀ ꢀ ꢀN1A
C3A—H3ꢀ ꢀ ꢀN8Aii
C5A—H5ꢀ ꢀ ꢀO1iii
C4A—H4ꢀ ꢀ ꢀF3iv
0.85
0.96
0.96
0.96
1.89
2.60
2.48
2.53
2.7257 (14)
3.4958 (18)
3.4203 (18)
3.3445 (17)
166
155
165
143
1
2
1
2
1
2
1
2
1
2
1
2
3
2
Symmetry codes: (ii) x þ ; ꢃy þ ; z þ ; (iii) x þ ; ꢃy þ ; z ꢃ ; (iv) ꢃx þ ,
1
2
1
2
y ꢃ ; ꢃz þ .
The authors thank Mr Paweł Rusak for assistance at the
start of this project.
Refinement
R[F2 > 2ꢆ(F2)] = 0.031
wR(F2) = 0.084
S = 1.06
200 parameters
H-atom parameteꢃrs3 constrained
˚
Áꢇmax = 0.17 e A
ꢃ3
˚
1324 reflections
Áꢇmin = ꢃ0.15 e A
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: SU3047). Services for accessing these data are
described at the back of the journal.
Compound (III)
Crystal data
References
3
˚
V = 1224.01 (12) A
Z = 2
Mo Kꢁ radiation
ꢄ = 0.12 mmꢃ1
T = 294 K
C6H2F4O2ꢀ2C12H8N2
Mr = 542.48
Monoclinic, P21=n
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a = 9.1482 (5) A
b = 11.0393 (6) A
˚
c = 12.4185 (8) A
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ꢂ = 102.585 (5)ꢁ
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Gotoh, K., Asaji, T. & Ishida, H. (2008). Acta Cryst. C64, o550–o553.
Gotoh, K., Nagoshi, H. & Ishida, H. (2007). Acta Cryst. E63, o4295.
Horiuchi, S., Ishii, F., Kumai, R., Okimoto, Y., Tachibana, H., Nagaosa, N. &
Tokura, Y. (2005). Nat. Mater. 4, 163–166.
Data collection
Kuma KM-4 CCD diffractometer in
ꢅ geometry
8327 measured reflections
2476 independent reflections
1862 reflections with I > 2ꢆ(I)
Rint = 0.024
Horiuchi, S. F., Kumai, R. & Tokura, Y. (2005). J. Am. Chem. Soc. 127, 5010–
5011.
Refinement
Kadzewski, A. & Gdaniec, M. (2006). Acta Cryst. E62, o3498–o3500.
Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor,
R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.
Oxford Diffraction (2004). CrysAlis CCD and CrysAlis RED. Versions 1.171.
Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.
Rusak, P. & Gdaniec, M. (2006). Acta Cryst. E62, o1650–o1651.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
R[F2 > 2ꢆ(F2)] = 0.041
wR(F2) = 0.125
S = 1.07
182 parameters
H-atom parameteꢃrs3 constrained
˚
Áꢇmax = 0.23 e A
ꢃ3
˚
2476 reflections
Áꢇmin = ꢃ0.20 e A
Thalladi, V. R., Smolka, T., Boese, R. & Sustmann, R. (2000). CrystEngComm,
2, 96–101.
Thalladi, V. R., Weiss, H.-C., Boese, R., Nangia, A. & Desiraju, G. R. (1999).
Acta Cryst. B55, 1005–1013.
Tomura, M. & Yamashita, Y. (2000). CrystEngComm, 2, 92–95.
In (II), in the absence of significant anomalous scattering effects,
Friedel pairs were averaged. The H atoms from the O—H groups
were located in electron-density difference maps. In the final cycles of
refinement, they and the C-bound H atoms were included in calcu-
ꢂ
o360 Czapik and Gdaniec
C6H2F4O2ꢀC4H4N2, C6H2F4O2ꢀC8H6N2 and C6H2F4O2ꢀ2C12H8N2
Acta Cryst. (2010). C66, o356–o360