Isomeric iodo-N-(nitrobenzyl)anilines: interplay of hard and soft hydrogen bonds, iodo...nitro interactions and aromatic pi...pi stacking interactions.

Molecules of 2-iodo-N-(4-nitrobenzyl)aniline, 4-O2NC6H4CH2NHC6H4I-2' (1) are linked into chains by C-H...O hydrogen bonds. In the isomeric compound 3-iodo-N-(4-nitrobenzyl)aniline (2) a combination of N-H...O and C-H...O hydrogen bonds and iodo...nitro and aromatic pi...pi stacking interactions links the molecules into a three-dimensional framework structure. The two-dimensional supramolecular structure of 4-iodo-N-(4-nitrobenzyl)aniline (6) is built from a combination of C-H...O and N-H...pi(arene) hydrogen bonds and aromatic pi...pi stacking interactions. 2-Iodo-N-(2-nitrobenzyl)aniline (7) crystallizes with two molecules in the asymmetric unit and these molecules are linked into ladders by a combination of N-H...O and C-H...O hydrogen bonds and iodo...nitro and aromatic pi...pi stacking interactions. Comparisons are made between the supramolecular structures of these compounds and those of other isomers, in terms both of the types of direction-specific intermolecular interactions exhibited and the dimensionality of the resulting supramolecular structures.