organic compounds
other site. Detailed analysis of the molecular geometry in (II)
is, of course, complicated by the orientational disorder.
Nonetheless, the pattern of the CÐC bond distances in the
aryl rings coupled with the dimensions of the nitro groups
provides evidence for some contribution from the polarized
form (IIa).
Molecules of (I) are linked into sheets by a combination of
NÐHÁ Á ÁO and CÐHÁ Á ÁO hydrogen bonds (Table 2), which
act in pairs to form two distinct one-dimensional substruc-
tures. Atoms N1 and C2 in the molecule at (x, y, z) both act as
donors to atom O41 in the molecule at (12 + x, 23 y, 21 + z), so
forming a C(6)C(6)[R12(6)] (Bernstein et al., 1995) chain of
rings running parallel to the [101] direction and generated by
the n-glide plane at y = 34 (Fig. 3). Similarly, atoms C6 and C16
by the 21 screw axis along (43, y, 14 ) (Fig. 5). If all the donor sites
within this chain were of the same atomic type, the chain
would be of C(10) type; on the other hand, if the site-occu-
pancies occur at random within each chain, as seems probable,
no periodically repeating motif can be de®ned.
In a similar manner, atoms N1B and C17A in the molecule
at (x, y, z) both act as hydrogen-bond donors to atom O41 in
1
2
the molecule at (12 + x,
y, 12 + z), so producing a chain
running parallel to the [101] direction and generated by the
1
4
n-glide plane at y = (Fig. 6). Again, this chain would be of
C(10) type if all donor sites were of the same type. The
combination of the [010] and [101] chains then generates a
(101) sheet, and adjacent sheets are linked by a third
hydrogen-bond motif in which a chain of centrosymmetric
rings is formed by two further CÐHÁ Á ÁO hydrogen bonds.
Atoms C3 and C6 in the molecule at (x, y, z) act as donors,
respectively, to atoms O42 and O43 in the molecules at
( 1 x, y, 1 z) and (2 x, 1 y, 1 z), so generating a
chain of alternating R22(10) and R22(24) rings running parallel
to the [310] direction, in which both types of ring are
centrosymmetric (Fig. 7). The combination of (101) sheets and
[310] chains generates a continuous three-dimensional
framework. Despite the effective planarity of the molecules,
intermolecular ꢀ±ꢀ stacking interactions are absent.
It is of interest to compare the structures reported here with
those of the analogous compounds benzaldehyde 4-nitro-
phenylhydrazone, (III) (Vickery et al., 1985), and benz-
aldehyde 2-nitrophenylhydrazone, (IV) (Drew et al., 1984). In
(III), the molecules are linked by one NÐHÁ Á ÁO hydrogen
bond and one CÐHÁ Á ÁO hydrogen bond into C(6)C(8)[R22(8)]
chains of rings, while in (IV), pairs of NÐHÁ Á ÁO hydrogen
bonds generate isolated R22(4) dimers. Thus, no two of the
compounds discussed here, whether nitrobenzaldehyde
hydrazones, nitrobenzaldehyde nitrophenylhydrazones or
benzaldehyde nitrophenylhydrazones, show similar patterns
of supramolecular aggregation.
at (x, y, z) both act as donors, albeit rather weakly, to atom
1
O22 in the molecule at ( 12 + x,
y, 12 + z), so forming a
2
second [101] chain, this time of C(9)C(10)[R12(10)] type,
generated by the n-glide plane at y = 14 (Fig. 4). The combined
action of the two types of [101] chain generates a (101) sheet.
Two sheets of this type, related to one another by inversion,
pass through each unit cell, but there are no signi®cant
direction-speci®c interactions between adjacent sheets.
The molecules of (II) are linked by an extensive series of
hydrogen bonds (Table 4), and the pattern of intermolecular
aggregation is independent of the molecular orientation at any
particular site. Atoms N1A and C17B in the molecule at (x, y,
z), which are alternative occupants of the same site, both act as
hydrogen-bond donors to atom O44 in the molecule at (32 x,
12 + y, 12 z), and propagation of these interactions produces
a chain running parallel to the [010] direction and generated
Figure 6
Part of the crystal structure of (II), showing the formation of a hydrogen-
bonded chain along [101]. The atom site denoted Y1 is occupied by
(0.5C + 0.5N) atoms (see Comment). For clarity, H atoms not involved in
the motif shown have been omitted. Atoms marked with an asterisk (*) or
a hash (#) are at the symmetry positions (12 + x, 21 y, 21 + z) and ( 21 + x,
Figure 7
A stereoview of part of the crystal structure of (II), showing the
formation of a [310] chain of alternating R22(10) and R22(24) rings. For
clarity, H atoms not involved in the motifs shown have been omitted.
1
2
y, 12 + z), respectively.
ꢀ
o12 James L. Wardell et al.
C13H10N4O4
Acta Cryst. (2005). C61, o10±o14
Wardell, James L.
