Received 22 August 2012
Eight isostructural 4,4'-disubstituted N-phenylbenzenesulfonamides
aInstitute of Pharmacy, University of Innsbruck, Innrain 52, 6020 Innsbruck, Austria,bSchool of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, England, and cDepartment of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah 21588, Saudi Arabia
The isostructural crystals of 4-cyano-N-(4-methoxyphenyl)benzenesulfonamide, C14H12N2O3S, (I), N-(4-methoxyphenyl)-4-(trifluoromethyl)benzenesulfonamide, C14H12F3NO3S, (II), 4-iodo-N-(4-methoxyphenyl)benzenesulfonamide, C13H12INO3S, (III), 4-bromo-N-(4-methoxyphenyl)benzenesulfonamide, C13H12BrNO3S, (IV), 4-chloro-N-(4-methoxyphenyl)benzenesulfonamide, C13H12ClNO3S, (V), 4-fluoro-N-(4-methoxyphenyl)benzenesulfonamide, C13H12FNO3S, (VI), N-(4-chlorophenyl)-4-methoxybenzenesulfonamide, C13H12ClNO3S, (VII), and 4-cyano-N-phenylbenzenesulfonamide, C13H10N2O2S, (VIII), contain infinite chains composed of N-HO(sulfonyl) hydrogen-bonded molecules. The crystal structures of (I)-(VIII) have been compared using the XPac software and quantitative descriptors of isostructurality were generated [Gelbrich, Threlfall & Hursthouse (2012). CrystEngComm, 14, 5454-5464]. Certain isostructural relationships in this series involve molecules with substantially different spatial demands, e.g. (VI) and (VIII) are related by the simultaneous interchange of FCN on the benzenesulfonamide ring and OMeH on the N-phenyl ring, which indicates that the geometry of the three-dimensional crystal-packing mode of (I)-(VIII) is unusually adaptable to different molecular shapes.
We have investigated families of crystal structures of closely related organic compounds in order to examine the effect of incremental changes in molecular shape, van der Waals interactions and other, more directed, intermolecular forces on the crystal packing (Hursthouse, 2004; Gelbrich & Hursthouse, 2006; Gelbrich et al., 2007, 2012; Hursthouse et al., 2010, 2011). One such family comprises a 10 × 10 matrix of 4,4'-disubstituted N-phenylbenzenesulfonamides of formula XC6H4-SO2-NH-C6H4Y, denoted X/Y, where X and Y are NO2, CN, CF3, I, Br, Cl, F, Me, OMe or H. A general overview of this set has been given previously (Gelbrich et al., 2007) and it was reported that all crystal structures investigated contain N-HA hydrogen-bonded molecules (A = hydrogen-bond acceptor). The crystal structures of the X/Y set were classified according to: (i) the type of A site employed; (ii) the connectivity type of the resulting N-HA bonded structure; (iii) the spatial arrangement of the molecules forming this hydrogen-bonded structure; and (iv) the complete three-dimensional crystal-packing arrangement (`structure type'). A subset of 22 isostructural X/Y compounds has been discussed in detail (Gelbrich et al., 2007). This particular structure type, denoted A1.1, is characterized by the presence of centrosymmetric N-HO(sulfonyl) hydrogen-bonded dimers, which are arranged around a axis.
In this contribution, we report another eight crystal structures of the X/Y matrix: CN/OMe, (I), CF3/OMe, (II), I/OMe, (III), Br/OMe, (IV), Cl/OMe, (V), F/OMe, (VI), OMe/Cl, (VII), and CN/H, (VIII). The crystals of (I)-(VIII) investigated here all have the space group Pna21. The asymmetric units of (I)-(VIII) each contain a single molecule (Fig. 1). The overlay in Fig. 2 illustrates that the molecular geometries are very similar throughout the series, except for the X and Y substituents. The most significant conformational differences between individual members may be described in terms of a slight rotation of the aromatic rings about the pseudo-axes S1-C1C4-X and N1-C7C10-Y. In the following we discuss details of the molecular and crystal structure of Cl/OMe, (V), which is representative of the entire series of structures (I)-(VIII), denoted previously as type B1.10 (Gelbrich et al., 2007), where `B' indicates the presence of N-HO(sulfonyl) bonded chains, `1' indicates their specific geometry and `10' is the running number of structure types exhibiting these characteristics.
The V-shaped molecular geometry is characterized by the three torsion angles C2-C1-S1-N1 = -88.2 (3)°, C1-S1-N1-C7 = -67.9 (3)° and S1-N1-C7-C8 = 101.1 (3)°. The centroids of the two aromatic rings of (V) are 4.983 (4) Å apart and the mean planes of these two rings form an angle of 42.8 (1)°. The methoxy substituents Y in (I)-(VI) and X in (VII) are oriented in such a way that the OMe group is approximately coplanar with the attached aromatic ring. In (I)-(VI), the terminal O3-C bond is oriented approximately parallel to the C7-C12 bond of the ring, and in (VII) it lies parallel to the C1-C2 bond.
Each molecule is linked to two other molecules via an N1-HO1(sulfonyl) interaction (Table 1). The resulting hydrogen-bonded chain (Fig. 3) has a V-shaped cross section and propagates parallel to the c axis. Neighbouring chains of this kind are arranged into a layer structure, which lies parallel to the bc plane and possesses n-glide symmetry (Fig. 4). The stacking of these two-dimensional structures along  is such that the molecules of neighbouring layers are related by 21 and glide-symmetry operations.
The crystal structures of (I)-(VIII) were compared with each other using the program XPac (Gelbrich & Hursthouse, 2005), using geometric parameters generated from a set of 16 non-H atomic positions for each molecule, not including those of substituents X and Y. Each crystal structure was represented by a cluster consisting of a central molecule and its 14 closest neighbours. The complete clusters representing (I)-(VIII) were found to possess fundamentally the same geometry, indicating isostructurality. The isostructurality of the X/OMe series with X = CN, CF3, I, Br and Cl, i.e. (I)-(V), is not unusual, since the molecular shape varies relatively little in this group. However, each of (VI), (VII) and (VIII) differs quite substantially from these five compounds in the size of either or both of their X and Y substituents, so that their isostructurality with (I)-(V) is rather surprising.
To quantify the isostructural relationships in this set, the XPac dissimilarity index x (Gelbrich et al., 2012) and distance parameter d were calculated for all 28 comparisons between two individual structures. The results of these calculations are collected in Fig. 5; the dissimilarity parameters refer to clusters composed of a central molecule and its 14 closest neighbours, which represent complete crystal structures. As expected, the lowest x values ( 3.1), indicating the highest degree of similarity, were found for the X/OMe subset (I)-(V). The inclusion of the fluoro analogue, (VI), resulted in somewhat higher values (x 4.9) because F is considerably smaller than the other X substituents present in this subset. Even larger molecular-shape differences exist between (I)-(V) on the one hand and OMe/Cl, (VII), and in particular CN/H, (VIII), on the other. The modifications of the packing geometry are therefore more pronounced and the dissimilarity parameters for comparisons involving (VII) and (VIII) are systematically higher, at 3.7 x 5.2 and 6.8 x 7.9, respectively. Overall, the dissimilarity indices x for the B1.10 series are broadly consistent with trends identified in a recent study of close chemical analogues of (I)-(VIII) (Gelbrich et al., 2012).
OMe/Cl, (VII), and CN/H, (VIII), have the two least closely related packing arrangements in this group (x = 10.1). For a more detailed analysis, an individual dissimilarity parameter xi was calculated for each unit consisting of two next-neighbour molecules in the structures of (VII) and (VIII). The lowest xi value of 3.2 was obtained for the assembly of two N-HO-linked molecules, while for all other two-molecule units the values were considerably higher (10.0 xi 14.3). This indicates that the geometry of the hydrogen-bonded chain is very rigid. Therefore, adjustment for the different shape requirements of the various X and Y substituents consists mainly of a subtle change in the alignment of neighbouring N-HO hydrogen-bonded chains relative to one another.
| || Figure 1 |
The asymmetric units of (I)-(VIII), showing the atom-numbering schemes. Displacement ellipsoids are drawn at the 50% probability level.
| || Figure 2 |
An overlay of the molecular structures of (I) (red in the electronic version of the paper), (II) (orange), (III) (purple), (IV) (yellow), (V) (grey), (VI) (dark blue), (VII) (light blue) and (VIII) (green), based on a least-squares fit of 16 atomic positions (all non-H atoms, except those of the X and Y substituents). H atoms have been omitted for clarity.
| || Figure 3 |
The N-HO hydrogen-bonded chain in the crystal structure of Cl/OMe, (V). O, N and H atoms directly involved in hydrogen bonding are drawn as spheres.
| || Figure 4 |
The crystal packing of (V), (VII) and (VIII), viewed parallel to the c axis, with X and Y substituents drawn as spheres. N-HO hydrogen-bonded chains, which propagate parallel to , are represented by a single molecule. The layer structure highlighted by dot-dashed lines (left diagram) is the result of the stacking of these chains via a glide operation. Note that OMe/Cl, (VII), and CN/H, (VIII), show the largest differences (dissimilarity index x = 10.1) of all investigated structures.
| || Figure 5 |
An XPac map (Gelbrich & Hursthouse, 2005; Gelbrich et al., 2012), showing the dissimilarity indices x (lower left section of the matrix) and distance parameters d (upper right section) for the 28 binary structure comparisons in the investigated set.
The structure models of (I) and (IV)-(VIII) were refined using matching sets of atomic coordinates, with the z coordinate of atom S1 at approximately 0.5. The corresponding inverted model was used in the cases of (II) and (III). All H atoms were identified in a difference map. Methyl H atoms were idealized and included as rigid groups allowed to rotate but not tip, with C-H = 0.98 Å, and refined with Uiso(H) = 1.5Ueq(C). H atoms attached to aromatic C atoms were positioned geometrically, with C-H = 0.95 Å, and refined with Uiso(H) = 1.2Ueq(C). H atoms attached to the N atoms were refined with restrained distances [N-H = 0.86 (2) Å], and their Uiso(H) parameters were refined freely.
For all compounds, data collection: COLLECT (Nonius, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: XP (Bruker, 1998) and Mercury (Macrae et al., 2008); software used to prepare material for publication: publCIF (Westrip, 2010).
Supplementary data for this paper are available from the IUCr electronic archives (Reference: UK3052 ). Services for accessing these data are described at the back of the journal.
MBH thanks the Leverhulme Trust for the award of an Emeritus Fellowship.
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