hydrazine: a three-dimensional framework containing four types of hydrogen bond

Instituto de Tecnologia em Fármacos, Far-Manguinhos, FIOCRUZ, 21041-250 Rio de Janeiro, RJ, Brazil, Instituto de Quı́mica, Departamento de Quı́mica Inorgânica, Universidade Federal do Rio de Janeiro, CP 68563, 21945-970 Rio de Janeiro, RJ, Brazil, Department of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen AB24 3UE, Scotland, and School of Chemistry, University of St Andrews, Fife KY16 9ST, Scotland

Compound (I) crystallizes with Z 0 = 2 in space group Fdd2, with a unit cell of markedly tabular shape, as shown by the axial ratios a:b:c of 1.958:1:0.134, so that the ratio c/a is only 0.0686. The two independent molecules adopt significantly different conformations, as shown by the leading torsion angles (Table 1).
The molecules of (I) are linked by a combination of four types of hydrogen bond (Table 2) to form a fairly complex three-dimensional framework, whose formation is nonetheless readily analysed in terms of three distinct substructures. Within the selected asymmetric unit, the two molecules are linked by an N-HÁ Á ÁN hydrogen bond, possibly weakly augmented by a C-HÁ Á ÁN hydrogen bond, and these bimolecular units are linked by two N-HÁ Á ÁO hydrogen bonds into a chain of edge-fused R 4 4 (26) (Bernstein et al., 1995) rings generated by translation along the [001] direction (Fig. 2). In the second substructure, the bimolecular units are linked by the second N-HÁ Á ÁN hydrogen bond, in which atom N37 at (x, y, z) acts as donor to atom N11 at ( 3 4 À x, À 1 4 + y, 1 4 + z), so forming a C 2 2 (14) chain running parallel to the [011] direction and generated by the d-glide plane at x = 0.375 (Fig. 3). This chain may be weakly reinforced by a second C-HÁ Á ÁN hydrogen bond. In the final substructure, atom C44 at (x, y, z) acts as hydrogen-bond donor to atom O1 at ( 1 4 + x, 3 4 À y, 7 4 + z), so forming a C 2 2 (17) chain running parallel to the [107] direction and generated by the d-glide plane at y = 0.375 (Fig. 4) Experimental 5-Chloro-2-nitrobenzoyl chloride was prepared from the corresponding carboxylic acid (1 g) using thionyl chloride (3 molar equivalents) and N,N-dimethylformamide (0.1 equivalent) in dichloromethane (20 ml) at ambient temperature with stirring and in a dinitrogen atmosphere. After 6 h, the excess of thionyl chloride was removed under reduced pressure to leave the crude acyl chloride, which was used without purification in a reaction with isonicotinoylhydrazine (isoniazid, 1 molar equivalent) in refluxing tetrahydrofuran (20 ml). The mixture was then cooled and the solvent removed under reduced pressure. The crude solid product, (I), was purified by column chromatography on silica gel, using as eluant a hexane-ethyl acetate gradient. Recrystallization from ethanol gave crystals suitable for single-crystal X-ray diffraction [yield 75%, m.p.  The structures of the two independent molecules of compound (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level.

Figure 2
A stereoscopic view of part of the crystal structure of compound (I), showing the formation of a hydrogen-bonded (dashed lines) chain of R 4 4 (26) rings generated by translation along [001]. For the sake of clarity, the unit-cell outline and H atoms bonded to C atoms have been omitted.

Figure 3
A stereoscopic view of part of the crystal structure of compound (I), showing the formation of a hydrogen-bonded (dashed lines) C 2 2 (14) chain along [011]. For the sake of clarity, H atoms bonded to C atoms have been omitted.

Figure 4
A stereoscopic view of part of the crystal structure of compound (I), showing the formation of a hydrogen-bonded (dashed lines) C 2 2 (17) chain along [107]. For the sake of clarity, H atoms bonded to C atoms but not involved in the motif shown have been omitted.
All H atoms were located in difference maps and then treated as riding, with C-H = 0.95 Å and N-H = 0.88 Å , and with U iso (H) = 1.2U eq (C,N). The unit-cell dimensions posed some difficulties during the data collection, and there was effectively no scattering beyond = 22 .