Received 14 October 2005
2-(3-Nitrophenylaminocarbonyl)benzoic acid: hydrogen-bonded sheets of R44(22) rings
aSchool of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland,bDepartment of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen AB24 3UE, Scotland, and cInstituto de Química, Departamento de Química Inorgânica, Universidade Federal do Rio de Janeiro, 21945-970 Rio de Janeiro, RJ, Brazil
In the title compound, C14H10N2O5, the molecules are linked by a combination of one N-HO and one O-HO hydrogen bond into sheets containing a single type of R44(22) ring.
We recently reported the molecular and supramolecular structures of 2-(2-nitrophenylaminocarbonyl)benzoic acid, (I), and two polymorphs, one orthorhombic with space group P212121 and the other monoclinic with space group P21/n, of 2-(4-nitrophenylaminocarbonyl)benzoic acid, (III) (Glidewell et al., 2004). In the 2-nitro isomer, compound (I), the molecules form R22(8) carboxylic acid dimers, which are linked into sheets by - stacking interactions, but intermolecular N-HO hydrogen bonds are absent. In the orthorhombic polymorph of the 4-nitro isomer, (III), the molecules are linked into sheets of R44(22) rings built from a combination of two C(7) chains, formed by N-HO and O-HO hydrogen bonds, respectively. In the monoclinic polymorph of (III), where Z' = 2, the molecules are linked into a continuous, which, although it crystallizes in a monoclinic space group, P21, with unit-cell dimensions very different from those of the orthorhombic polymorph of (III), nonetheless forms a supramolecular structure very similar to that of orthorhombic (III).
In compound (II), the C-O bond distances (Table 1) within the carboxyl group are consistent with the location of the carboxyl H atom as deduced from a difference map. The torsion angles (Table 1 and Fig. 1) indicate that the molecules of (II) have no internal symmetry and hence they are chiral. Thus, in the absence of any inversion twinning, each crystal will contain just a single enantiomorph of (II). However, this chirality in the solid state has no chemical significance.
The molecules of (II) (Fig. 1) are linked into sheets by a combination of one N-HO hydrogen bond and one O-HO hydrogen bond, and the formation of the sheet is most readily analysed in terms of the one-dimensional substructures generated by the two individual hydrogen bonds.
Amino atom N1 in the molecule at (x, y, z) acts as hydrogen-bond donor to carboxyl atom O22 in the molecule at (-1 + x, y, z), so generating by translation a C(7) (Bernstein et al., 1995) chain running parallel to the  direction (Fig. 2). At the same time, carboxyl atom O21 at (x, y, z) acts as donor to amide atom O1 in the molecule at (2 - x, - + y, 1 - z), so forming a second C(7) chain, this time running parallel to the  direction and generated by the 21 screw axis along (1, y, ) (Fig. 3). It is noteworthy that the C(4) motif so characteristic of simple amides is absent. Likewise, the motifs characteristic of simple carboxylic acids, namely the C(4) chain and the R22(8) cyclic dimer motif, are both absent.
The combination of these two simple chains along  and  generates an (001) sheet in the form of a (4,4)-net built from a single type of R44(22) (Bernstein et al., 1995) ring (Fig. 4). Despite the presence of two independent aryl rings, there are neither C-H(arene) hydrogen bonds nor aromatic - stacking interactions present in the structure of isomer (II), and there are, in fact, no direction-specific interactions between adjacent (001) sheets.
It is of interest to note that, despite their different space groups and unit-cell dimensions, isomer (II) as reported here, and the orthorhombic polymer of isomer (III) (Glidewell et al., 2004) form exactly the same two types of C(7) chain built from N-HO and O-HO hydrogen bonds, generated by translation along  and by a 21 screw axis along , respectively, with the combination of these two chains producing a sheet of R44(22) rings in both structures. Not only do the nitro groups play no direct role in the hydrogen-bonding scheme, but in these two examples they appear to exert no significant influence on the overall supramolecular aggregation.
| || Figure 1 |
The molecule of compound (II), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.
| || Figure 2 |
Part of the crystal structure of (II), showing the formation of a C(7) chain along . Atoms marked with an asterisk (*) or a hash (#) are at the symmetry positions (-1 + x, y, z) and (1 + x, y, z), respectively.
| || Figure 3 |
Part of the crystal structure of (II), showing the formation of a C(7) chain along . Atoms marked with an asterisk (*) or a hash (#) are at the symmetry positions (2 - x, - + y, 1 - z) and (2 - x, + y, 1 - z), respectively.
| || Figure 4 |
Stereoview of part of the crystal structure of (II), showing the formation of an (001) sheet of R44(22) rings.
The title compound was prepared by the reaction of equimolar quantities of 3-nitroaniline and phthalic anhydride (2 mmol of each) in chloroform solution (20 ml), following the procedure used for the preparation of the 2-nitro and 4-nitro isomers (Glidewell et al., 2004). Crystals of (II) suitable for single-crystal X-ray diffraction were grown by slow evaporation of a solution in ethanol (m.p. 440-442 K).
For compound (II), the systematic absences permitted P21 and P21/m as possible space groups; P21 was selected and confirmed by the successful structure analysis. All H atoms were located in difference maps, but they were subsequently treated as riding atoms, with C-H = 0.95 Å, N-H = 0.88 Å and O-H = 0.84 Å, and with Uiso(H) = 1.2Ueq(C,N) or 1.5Ueq(O). In the absence of significant anomalous scattering, the Flack (1983) parameter was indeterminate (Flack & Bernardinelli, 2000). Accordingly, it was not possible to determine the absolute configuration of the molecules in the crystal selected for data collection, although this has no chemical significance. Friedel-equivalent reflections were merged prior to the final refinement.
Data collection: COLLECT (Nonius, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: OSCAIL (McArdle, 2003) and SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: OSCAIL and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).
Supplementary data for this paper are available from the IUCr electronic archives (Reference: SK1880 ). Services for accessing these data are described at the back of the journal.
The X-ray data were collected at the EPSRC X-ray Crystallographic Service, University of Southampton, England; the authors thank the staff for all their help and advice. JLW thanks CNPq and FAPERJ for financial support.
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