Supramolecular structures of three isomeric (E,E)-1-(2-iodophenyl)-4-(nitrophenyl)-2,3-diaza-1,3-butadienes:: changes in intermolecular interactions consequent upon changes of substituent location

The supramolecular structures of the three isomeric (E,E)-1-(2-iodophenyl)-4-(2/3/4-nitrophenyl)-2,3-diaza-1,3-butadienes, C14H10IN3O2, are compared. In the 2-nitro isomer, the molecules are disordered across centres of inversion in space group C2/c and are linked into chains by a two-centre iodo-nitro interaction. The molecules of the 3-nitro isomer are linked into a three-dimensional framework by a combination of C-H center dot center dot center dot O and C-H center dot center dot center dot I hydrogen bonds and aromatic, pi-pi stacking interactions, while molecules of the 4-nitro isomer are linked into sheets by a C-H center dot center dot center dot O hydrogen bond and a two-centre iodo-nitro interaction.