organic compounds
ring orientation with respect to the pyridine ring (Fig. 4). The
dihedral angles between the best planes of the pyridyl and
Glidewell et al. (2004), and references therein] is, however, not
observed for (I), but only for the structures of (II) and (III).
In contrast with (I), where the C(4) and C(6) chains are
helical, the C(6) chains in compound (II) are formed by pure
translation parallel to the a axis (Fig. 6), whereby the N34Ð
H341Á Á ÁN1 hydrogen bond connects the molecules (denoted
A, B, C, D, etc.). The second chain is built up from molecules
ꢀ
benzene rings are 93.95 (7), 117.75 (5) and 122.40 (5) in (I),
(
II) and (III), respectively. The conformation of the 4-amino-
pyridine-3-sulfonamide part of the molecule is conserved by
an intramolecular N4ÐH4Á Á ÁO32 hydrogen bond and a C2Ð
H2Á Á ÁO33 interaction in all three isomers. The C4ÐC3Ð
0
0
0
0
S31ÐN34 torsion angles are 65.22 (17), 77.27 (13) and
(denoted A , B , C , D , etc.) related to the ®rst chain by
0
ꢀ
5
8.82 (17) in (I), (II) and (III), respectively.
Although the same intermolecular hydrogen-bonding types
inversion. Centrosymmetrically related molecules B/B , etc.,
are connected by intermolecular N4ÐH4Á Á ÁO32 hydrogen
2
2
(
sulfonamide NH groups as donors to sulfonamide O or
2
bonds to form dimers involving R (4) rings. By these inter-
actions, two antiparallel C(6) chains form one ribbon through
pyridine N atoms) are observed in all three structures (Tables
±3), their supramolecular structures are appreciably
different.
In compound (I), two major chains, viz. C(4) and C(6), are
1
formed via N34ÐH342Á Á ÁO33 and N34ÐH341Á Á ÁN1
hydrogen bonds, respectively. Both chains run parallel to the b
4
axis and combine to form a tetramolecular R (18) motif.
4
Additional linking across these 18-membered rings is realised
by weak C6ÐH6Á Á ÁO32 interactions forming a C(7) chain
parallel to the a axis. These three chains combine to form
layers parallel to (001) (Fig. 5).
The observed C(4) chain motif is characteristic of simple
sulfonamides. The most characteristic hydrogen-bond motif of
2
2
sulfonamides, the R (8) ring [for a discussion of both types, see
Figure 6
Part of the unit-cell packing in (II), viewed perpendicular to the ab plane,
1
showing the hydrogen-bonded layer in the region around z = . Dashed
0
2
lines indicate hydrogen bonds. Molecules A, B , etc., are as de®ned in the
Comment. Methylphenyl C atoms, and H atoms not involved in hydrogen
bonds, have been omitted for clarity. Atoms marked with an asterisk (*),
hash (#) or dollar sign ($) are at the symmetry positions (1 + x, y, z),
(
2 � x, 1 � y, 1 � z) and (2 � x, 1 � y, 1 � z), respectively.
Figure 4
Superimposition of (I), (II) and (III), showing the different benzene-ring
orientations. Compound (I) is shown with solid lines, (II) with dashed
lines and (III) with dotted lines (WebLab ViewerPro; Accelrys, 2000).
Figure 5
Part of the unit-cell packing in (I), viewed perpendicular to the ab plane,
Figure 7
Part of the unit-cell packing in (III), viewed perpendicular to the bc plane,
showing the hydrogen-bonded layer in the region around x = 1. Dashed
lines indicate hydrogen bonds. Methylphenyl C atoms, and H atoms not
involved in hydrogen bonds, have been omitted for clarity. Atoms marked
with an asterisk (*), hash (#) or dollar sign ($) are at the symmetry
1
showing the hydrogen-bonded layer in the region around z = . Dashed
4
lines indicate hydrogen bonds. Methylphenyl C atoms, and H atoms not
involved in hydrogen bonds, have been omitted for clarity. Atoms marked
with an asterisk (*), hash (#) or dollar sign ($) are at the symmetry
5
1
2
1
3
2
1
2
1
1
2
1
2
1
2
3
2
positions ( � x, + y, 2 � z), ( � x, + y, 2 � z) and (x � 1, y, z),
positions (2 � x, � y, 1 � z), (x, � y, + z) and (2 � x, + y, � z),
2
respectively.
respectively.
Acta Cryst. (2005). C61, o648±o651
Ko Ïs uti c Hulita et al.
ꢁ
Three isomers of C12
13 3 2
H N O S
o649