Four nitrobenzaldehyde isonicotinoylhydrazones at 120 K: four different supramolecular structures in two and three dimensions.

The molecules of 2-nitrobenzaldehyde isonicotinoylhydrazone, C13H10N4O3, (I), are linked into a three-dimensional framework by a combination of one N-H...N and three C-H...O hydrogen bonds. In the isomeric compound 3-nitrobenzaldehyde isonicotinoylhydrazone, (II), the molecules are linked into complex sheets by a combination of three hydrogen bonds, one each of the N-H...N, C-H...N and C-H...O types. The molecules of the third isomer, namely 4-nitrobenzaldehyde isonicotinoylhydrazone, (III), are linked into bilayers by a combination of one N-H...N, one C-H...N and two C-H...O hydrogen bonds. 2,4-Dinitrobenzaldehyde isonicotinoylhydrazone, (IV), crystallizes as a stoichiometric monohydrate, C13H9N5O5.H2O, and the molecular components are linked into a three-dimensional framework by a combination of O-H...O, O-H...N, N-H...O and three independent C-H...O hydrogen bonds.